fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "tree-log.h"
  20 #include "disk-io.h"
  21 #include "print-tree.h"
  22 #include "volumes.h"
  23 #include "raid56.h"
  24 #include "locking.h"
  25 #include "free-space-cache.h"
  26 #include "free-space-tree.h"
  27 #include "math.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31
  32 #undef SCRAMBLE_DELAYED_REFS
  33
  34 /*
  35  * control flags for do_chunk_alloc's force field
  36  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  37  * if we really need one.
  38  *
  39  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  40  * if we have very few chunks already allocated.  This is
  41  * used as part of the clustering code to help make sure
  42  * we have a good pool of storage to cluster in, without
  43  * filling the FS with empty chunks
  44  *
  45  * CHUNK_ALLOC_FORCE means it must try to allocate one
  46  *
  47  */
  48 enum {
  49         CHUNK_ALLOC_NO_FORCE = 0,
  50         CHUNK_ALLOC_LIMITED = 1,
  51         CHUNK_ALLOC_FORCE = 2,
  52 };
  53
  54 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  55                                struct btrfs_delayed_ref_node *node, u64 parent,
  56                                u64 root_objectid, u64 owner_objectid,
  57                                u64 owner_offset, int refs_to_drop,
  58                                struct btrfs_delayed_extent_op *extra_op);
  59 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  60                                     struct extent_buffer *leaf,
  61                                     struct btrfs_extent_item *ei);
  62 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  63                                       u64 parent, u64 root_objectid,
  64                                       u64 flags, u64 owner, u64 offset,
  65                                       struct btrfs_key *ins, int ref_mod);
  66 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  67                                      struct btrfs_delayed_ref_node *node,
  68                                      struct btrfs_delayed_extent_op *extent_op);
  69 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
  70                           int force);
  71 static int find_next_key(struct btrfs_path *path, int level,
  72                          struct btrfs_key *key);
  73 static void dump_space_info(struct btrfs_fs_info *fs_info,
  74                             struct btrfs_space_info *info, u64 bytes,
  75                             int dump_block_groups);
  76 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  77                                u64 num_bytes);
  78 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
  79                                      struct btrfs_space_info *space_info,
  80                                      u64 num_bytes);
  81 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
  82                                      struct btrfs_space_info *space_info,
  83                                      u64 num_bytes);
  84
  85 static noinline int
  86 block_group_cache_done(struct btrfs_block_group_cache *cache)
  87 {
  88         smp_mb();
  89         return cache->cached == BTRFS_CACHE_FINISHED ||
  90                 cache->cached == BTRFS_CACHE_ERROR;
  91 }
  92
  93 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  94 {
  95         return (cache->flags & bits) == bits;
  96 }
  97
  98 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  99 {
 100         atomic_inc(&cache->count);
 101 }
 102
 103 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 104 {
 105         if (atomic_dec_and_test(&cache->count)) {
 106                 WARN_ON(cache->pinned > 0);
 107                 WARN_ON(cache->reserved > 0);
 108
 109                 /*
 110                  * If not empty, someone is still holding mutex of
 111                  * full_stripe_lock, which can only be released by caller.
 112                  * And it will definitely cause use-after-free when caller
 113                  * tries to release full stripe lock.
 114                  *
 115                  * No better way to resolve, but only to warn.
 116                  */
 117                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 118                 kfree(cache->free_space_ctl);
 119                 kfree(cache);
 120         }
 121 }
 122
 123 /*
 124  * this adds the block group to the fs_info rb tree for the block group
 125  * cache
 126  */
 127 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 128                                 struct btrfs_block_group_cache *block_group)
 129 {
 130         struct rb_node **p;
 131         struct rb_node *parent = NULL;
 132         struct btrfs_block_group_cache *cache;
 133
 134         spin_lock(&info->block_group_cache_lock);
 135         p = &info->block_group_cache_tree.rb_node;
 136
 137         while (*p) {
 138                 parent = *p;
 139                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 140                                  cache_node);
 141                 if (block_group->key.objectid < cache->key.objectid) {
 142                         p = &(*p)->rb_left;
 143                 } else if (block_group->key.objectid > cache->key.objectid) {
 144                         p = &(*p)->rb_right;
 145                 } else {
 146                         spin_unlock(&info->block_group_cache_lock);
 147                         return -EEXIST;
 148                 }
 149         }
 150
 151         rb_link_node(&block_group->cache_node, parent, p);
 152         rb_insert_color(&block_group->cache_node,
 153                         &info->block_group_cache_tree);
 154
 155         if (info->first_logical_byte > block_group->key.objectid)
 156                 info->first_logical_byte = block_group->key.objectid;
 157
 158         spin_unlock(&info->block_group_cache_lock);
 159
 160         return 0;
 161 }
 162
 163 /*
 164  * This will return the block group at or after bytenr if contains is 0, else
 165  * it will return the block group that contains the bytenr
 166  */
 167 static struct btrfs_block_group_cache *
 168 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 169                               int contains)
 170 {
 171         struct btrfs_block_group_cache *cache, *ret = NULL;
 172         struct rb_node *n;
 173         u64 end, start;
 174
 175         spin_lock(&info->block_group_cache_lock);
 176         n = info->block_group_cache_tree.rb_node;
 177
 178         while (n) {
 179                 cache = rb_entry(n, struct btrfs_block_group_cache,
 180                                  cache_node);
 181                 end = cache->key.objectid + cache->key.offset - 1;
 182                 start = cache->key.objectid;
 183
 184                 if (bytenr < start) {
 185                         if (!contains && (!ret || start < ret->key.objectid))
 186                                 ret = cache;
 187                         n = n->rb_left;
 188                 } else if (bytenr > start) {
 189                         if (contains && bytenr <= end) {
 190                                 ret = cache;
 191                                 break;
 192                         }
 193                         n = n->rb_right;
 194                 } else {
 195                         ret = cache;
 196                         break;
 197                 }
 198         }
 199         if (ret) {
 200                 btrfs_get_block_group(ret);
 201                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 202                         info->first_logical_byte = ret->key.objectid;
 203         }
 204         spin_unlock(&info->block_group_cache_lock);
 205
 206         return ret;
 207 }
 208
 209 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 210                                u64 start, u64 num_bytes)
 211 {
 212         u64 end = start + num_bytes - 1;
 213         set_extent_bits(&fs_info->freed_extents[0],
 214                         start, end, EXTENT_UPTODATE);
 215         set_extent_bits(&fs_info->freed_extents[1],
 216                         start, end, EXTENT_UPTODATE);
 217         return 0;
 218 }
 219
 220 static void free_excluded_extents(struct btrfs_block_group_cache *cache)
 221 {
 222         struct btrfs_fs_info *fs_info = cache->fs_info;
 223         u64 start, end;
 224
 225         start = cache->key.objectid;
 226         end = start + cache->key.offset - 1;
 227
 228         clear_extent_bits(&fs_info->freed_extents[0],
 229                           start, end, EXTENT_UPTODATE);
 230         clear_extent_bits(&fs_info->freed_extents[1],
 231                           start, end, EXTENT_UPTODATE);
 232 }
 233
 234 static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
 235 {
 236         struct btrfs_fs_info *fs_info = cache->fs_info;
 237         u64 bytenr;
 238         u64 *logical;
 239         int stripe_len;
 240         int i, nr, ret;
 241
 242         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 243                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 244                 cache->bytes_super += stripe_len;
 245                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 246                                           stripe_len);
 247                 if (ret)
 248                         return ret;
 249         }
 250
 251         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 252                 bytenr = btrfs_sb_offset(i);
 253                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 254                                        bytenr, &logical, &nr, &stripe_len);
 255                 if (ret)
 256                         return ret;
 257
 258                 while (nr--) {
 259                         u64 start, len;
 260
 261                         if (logical[nr] > cache->key.objectid +
 262                             cache->key.offset)
 263                                 continue;
 264
 265                         if (logical[nr] + stripe_len <= cache->key.objectid)
 266                                 continue;
 267
 268                         start = logical[nr];
 269                         if (start < cache->key.objectid) {
 270                                 start = cache->key.objectid;
 271                                 len = (logical[nr] + stripe_len) - start;
 272                         } else {
 273                                 len = min_t(u64, stripe_len,
 274                                             cache->key.objectid +
 275                                             cache->key.offset - start);
 276                         }
 277
 278                         cache->bytes_super += len;
 279                         ret = add_excluded_extent(fs_info, start, len);
 280                         if (ret) {
 281                                 kfree(logical);
 282                                 return ret;
 283                         }
 284                 }
 285
 286                 kfree(logical);
 287         }
 288         return 0;
 289 }
 290
 291 static struct btrfs_caching_control *
 292 get_caching_control(struct btrfs_block_group_cache *cache)
 293 {
 294         struct btrfs_caching_control *ctl;
 295
 296         spin_lock(&cache->lock);
 297         if (!cache->caching_ctl) {
 298                 spin_unlock(&cache->lock);
 299                 return NULL;
 300         }
 301
 302         ctl = cache->caching_ctl;
 303         refcount_inc(&ctl->count);
 304         spin_unlock(&cache->lock);
 305         return ctl;
 306 }
 307
 308 static void put_caching_control(struct btrfs_caching_control *ctl)
 309 {
 310         if (refcount_dec_and_test(&ctl->count))
 311                 kfree(ctl);
 312 }
 313
 314 #ifdef CONFIG_BTRFS_DEBUG
 315 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 316 {
 317         struct btrfs_fs_info *fs_info = block_group->fs_info;
 318         u64 start = block_group->key.objectid;
 319         u64 len = block_group->key.offset;
 320         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 321                 fs_info->nodesize : fs_info->sectorsize;
 322         u64 step = chunk << 1;
 323
 324         while (len > chunk) {
 325                 btrfs_remove_free_space(block_group, start, chunk);
 326                 start += step;
 327                 if (len < step)
 328                         len = 0;
 329                 else
 330                         len -= step;
 331         }
 332 }
 333 #endif
 334
 335 /*
 336  * this is only called by cache_block_group, since we could have freed extents
 337  * we need to check the pinned_extents for any extents that can't be used yet
 338  * since their free space will be released as soon as the transaction commits.
 339  */
 340 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 341                        u64 start, u64 end)
 342 {
 343         struct btrfs_fs_info *info = block_group->fs_info;
 344         u64 extent_start, extent_end, size, total_added = 0;
 345         int ret;
 346
 347         while (start < end) {
 348                 ret = find_first_extent_bit(info->pinned_extents, start,
 349                                             &extent_start, &extent_end,
 350                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 351                                             NULL);
 352                 if (ret)
 353                         break;
 354
 355                 if (extent_start <= start) {
 356                         start = extent_end + 1;
 357                 } else if (extent_start > start && extent_start < end) {
 358                         size = extent_start - start;
 359                         total_added += size;
 360                         ret = btrfs_add_free_space(block_group, start,
 361                                                    size);
 362                         BUG_ON(ret); /* -ENOMEM or logic error */
 363                         start = extent_end + 1;
 364                 } else {
 365                         break;
 366                 }
 367         }
 368
 369         if (start < end) {
 370                 size = end - start;
 371                 total_added += size;
 372                 ret = btrfs_add_free_space(block_group, start, size);
 373                 BUG_ON(ret); /* -ENOMEM or logic error */
 374         }
 375
 376         return total_added;
 377 }
 378
 379 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 380 {
 381         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 382         struct btrfs_fs_info *fs_info = block_group->fs_info;
 383         struct btrfs_root *extent_root = fs_info->extent_root;
 384         struct btrfs_path *path;
 385         struct extent_buffer *leaf;
 386         struct btrfs_key key;
 387         u64 total_found = 0;
 388         u64 last = 0;
 389         u32 nritems;
 390         int ret;
 391         bool wakeup = true;
 392
 393         path = btrfs_alloc_path();
 394         if (!path)
 395                 return -ENOMEM;
 396
 397         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 398
 399 #ifdef CONFIG_BTRFS_DEBUG
 400         /*
 401          * If we're fragmenting we don't want to make anybody think we can
 402          * allocate from this block group until we've had a chance to fragment
 403          * the free space.
 404          */
 405         if (btrfs_should_fragment_free_space(block_group))
 406                 wakeup = false;
 407 #endif
 408         /*
 409          * We don't want to deadlock with somebody trying to allocate a new
 410          * extent for the extent root while also trying to search the extent
 411          * root to add free space.  So we skip locking and search the commit
 412          * root, since its read-only
 413          */
 414         path->skip_locking = 1;
 415         path->search_commit_root = 1;
 416         path->reada = READA_FORWARD;
 417
 418         key.objectid = last;
 419         key.offset = 0;
 420         key.type = BTRFS_EXTENT_ITEM_KEY;
 421
 422 next:
 423         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 424         if (ret < 0)
 425                 goto out;
 426
 427         leaf = path->nodes[0];
 428         nritems = btrfs_header_nritems(leaf);
 429
 430         while (1) {
 431                 if (btrfs_fs_closing(fs_info) > 1) {
 432                         last = (u64)-1;
 433                         break;
 434                 }
 435
 436                 if (path->slots[0] < nritems) {
 437                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 438                 } else {
 439                         ret = find_next_key(path, 0, &key);
 440                         if (ret)
 441                                 break;
 442
 443                         if (need_resched() ||
 444                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 445                                 if (wakeup)
 446                                         caching_ctl->progress = last;
 447                                 btrfs_release_path(path);
 448                                 up_read(&fs_info->commit_root_sem);
 449                                 mutex_unlock(&caching_ctl->mutex);
 450                                 cond_resched();
 451                                 mutex_lock(&caching_ctl->mutex);
 452                                 down_read(&fs_info->commit_root_sem);
 453                                 goto next;
 454                         }
 455
 456                         ret = btrfs_next_leaf(extent_root, path);
 457                         if (ret < 0)
 458                                 goto out;
 459                         if (ret)
 460                                 break;
 461                         leaf = path->nodes[0];
 462                         nritems = btrfs_header_nritems(leaf);
 463                         continue;
 464                 }
 465
 466                 if (key.objectid < last) {
 467                         key.objectid = last;
 468                         key.offset = 0;
 469                         key.type = BTRFS_EXTENT_ITEM_KEY;
 470
 471                         if (wakeup)
 472                                 caching_ctl->progress = last;
 473                         btrfs_release_path(path);
 474                         goto next;
 475                 }
 476
 477                 if (key.objectid < block_group->key.objectid) {
 478                         path->slots[0]++;
 479                         continue;
 480                 }
 481
 482                 if (key.objectid >= block_group->key.objectid +
 483                     block_group->key.offset)
 484                         break;
 485
 486                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 487                     key.type == BTRFS_METADATA_ITEM_KEY) {
 488                         total_found += add_new_free_space(block_group, last,
 489                                                           key.objectid);
 490                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 491                                 last = key.objectid +
 492                                         fs_info->nodesize;
 493                         else
 494                                 last = key.objectid + key.offset;
 495
 496                         if (total_found > CACHING_CTL_WAKE_UP) {
 497                                 total_found = 0;
 498                                 if (wakeup)
 499                                         wake_up(&caching_ctl->wait);
 500                         }
 501                 }
 502                 path->slots[0]++;
 503         }
 504         ret = 0;
 505
 506         total_found += add_new_free_space(block_group, last,
 507                                           block_group->key.objectid +
 508                                           block_group->key.offset);
 509         caching_ctl->progress = (u64)-1;
 510
 511 out:
 512         btrfs_free_path(path);
 513         return ret;
 514 }
 515
 516 static noinline void caching_thread(struct btrfs_work *work)
 517 {
 518         struct btrfs_block_group_cache *block_group;
 519         struct btrfs_fs_info *fs_info;
 520         struct btrfs_caching_control *caching_ctl;
 521         int ret;
 522
 523         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 524         block_group = caching_ctl->block_group;
 525         fs_info = block_group->fs_info;
 526
 527         mutex_lock(&caching_ctl->mutex);
 528         down_read(&fs_info->commit_root_sem);
 529
 530         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 531                 ret = load_free_space_tree(caching_ctl);
 532         else
 533                 ret = load_extent_tree_free(caching_ctl);
 534
 535         spin_lock(&block_group->lock);
 536         block_group->caching_ctl = NULL;
 537         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 538         spin_unlock(&block_group->lock);
 539
 540 #ifdef CONFIG_BTRFS_DEBUG
 541         if (btrfs_should_fragment_free_space(block_group)) {
 542                 u64 bytes_used;
 543
 544                 spin_lock(&block_group->space_info->lock);
 545                 spin_lock(&block_group->lock);
 546                 bytes_used = block_group->key.offset -
 547                         btrfs_block_group_used(&block_group->item);
 548                 block_group->space_info->bytes_used += bytes_used >> 1;
 549                 spin_unlock(&block_group->lock);
 550                 spin_unlock(&block_group->space_info->lock);
 551                 fragment_free_space(block_group);
 552         }
 553 #endif
 554
 555         caching_ctl->progress = (u64)-1;
 556
 557         up_read(&fs_info->commit_root_sem);
 558         free_excluded_extents(block_group);
 559         mutex_unlock(&caching_ctl->mutex);
 560
 561         wake_up(&caching_ctl->wait);
 562
 563         put_caching_control(caching_ctl);
 564         btrfs_put_block_group(block_group);
 565 }
 566
 567 static int cache_block_group(struct btrfs_block_group_cache *cache,
 568                              int load_cache_only)
 569 {
 570         DEFINE_WAIT(wait);
 571         struct btrfs_fs_info *fs_info = cache->fs_info;
 572         struct btrfs_caching_control *caching_ctl;
 573         int ret = 0;
 574
 575         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 576         if (!caching_ctl)
 577                 return -ENOMEM;
 578
 579         INIT_LIST_HEAD(&caching_ctl->list);
 580         mutex_init(&caching_ctl->mutex);
 581         init_waitqueue_head(&caching_ctl->wait);
 582         caching_ctl->block_group = cache;
 583         caching_ctl->progress = cache->key.objectid;
 584         refcount_set(&caching_ctl->count, 1);
 585         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 586                         caching_thread, NULL, NULL);
 587
 588         spin_lock(&cache->lock);
 589         /*
 590          * This should be a rare occasion, but this could happen I think in the
 591          * case where one thread starts to load the space cache info, and then
 592          * some other thread starts a transaction commit which tries to do an
 593          * allocation while the other thread is still loading the space cache
 594          * info.  The previous loop should have kept us from choosing this block
 595          * group, but if we've moved to the state where we will wait on caching
 596          * block groups we need to first check if we're doing a fast load here,
 597          * so we can wait for it to finish, otherwise we could end up allocating
 598          * from a block group who's cache gets evicted for one reason or
 599          * another.
 600          */
 601         while (cache->cached == BTRFS_CACHE_FAST) {
 602                 struct btrfs_caching_control *ctl;
 603
 604                 ctl = cache->caching_ctl;
 605                 refcount_inc(&ctl->count);
 606                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 607                 spin_unlock(&cache->lock);
 608
 609                 schedule();
 610
 611                 finish_wait(&ctl->wait, &wait);
 612                 put_caching_control(ctl);
 613                 spin_lock(&cache->lock);
 614         }
 615
 616         if (cache->cached != BTRFS_CACHE_NO) {
 617                 spin_unlock(&cache->lock);
 618                 kfree(caching_ctl);
 619                 return 0;
 620         }
 621         WARN_ON(cache->caching_ctl);
 622         cache->caching_ctl = caching_ctl;
 623         cache->cached = BTRFS_CACHE_FAST;
 624         spin_unlock(&cache->lock);
 625
 626         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 627                 mutex_lock(&caching_ctl->mutex);
 628                 ret = load_free_space_cache(fs_info, cache);
 629
 630                 spin_lock(&cache->lock);
 631                 if (ret == 1) {
 632                         cache->caching_ctl = NULL;
 633                         cache->cached = BTRFS_CACHE_FINISHED;
 634                         cache->last_byte_to_unpin = (u64)-1;
 635                         caching_ctl->progress = (u64)-1;
 636                 } else {
 637                         if (load_cache_only) {
 638                                 cache->caching_ctl = NULL;
 639                                 cache->cached = BTRFS_CACHE_NO;
 640                         } else {
 641                                 cache->cached = BTRFS_CACHE_STARTED;
 642                                 cache->has_caching_ctl = 1;
 643                         }
 644                 }
 645                 spin_unlock(&cache->lock);
 646 #ifdef CONFIG_BTRFS_DEBUG
 647                 if (ret == 1 &&
 648                     btrfs_should_fragment_free_space(cache)) {
 649                         u64 bytes_used;
 650
 651                         spin_lock(&cache->space_info->lock);
 652                         spin_lock(&cache->lock);
 653                         bytes_used = cache->key.offset -
 654                                 btrfs_block_group_used(&cache->item);
 655                         cache->space_info->bytes_used += bytes_used >> 1;
 656                         spin_unlock(&cache->lock);
 657                         spin_unlock(&cache->space_info->lock);
 658                         fragment_free_space(cache);
 659                 }
 660 #endif
 661                 mutex_unlock(&caching_ctl->mutex);
 662
 663                 wake_up(&caching_ctl->wait);
 664                 if (ret == 1) {
 665                         put_caching_control(caching_ctl);
 666                         free_excluded_extents(cache);
 667                         return 0;
 668                 }
 669         } else {
 670                 /*
 671                  * We're either using the free space tree or no caching at all.
 672                  * Set cached to the appropriate value and wakeup any waiters.
 673                  */
 674                 spin_lock(&cache->lock);
 675                 if (load_cache_only) {
 676                         cache->caching_ctl = NULL;
 677                         cache->cached = BTRFS_CACHE_NO;
 678                 } else {
 679                         cache->cached = BTRFS_CACHE_STARTED;
 680                         cache->has_caching_ctl = 1;
 681                 }
 682                 spin_unlock(&cache->lock);
 683                 wake_up(&caching_ctl->wait);
 684         }
 685
 686         if (load_cache_only) {
 687                 put_caching_control(caching_ctl);
 688                 return 0;
 689         }
 690
 691         down_write(&fs_info->commit_root_sem);
 692         refcount_inc(&caching_ctl->count);
 693         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 694         up_write(&fs_info->commit_root_sem);
 695
 696         btrfs_get_block_group(cache);
 697
 698         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 699
 700         return ret;
 701 }
 702
 703 /*
 704  * return the block group that starts at or after bytenr
 705  */
 706 static struct btrfs_block_group_cache *
 707 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 708 {
 709         return block_group_cache_tree_search(info, bytenr, 0);
 710 }
 711
 712 /*
 713  * return the block group that contains the given bytenr
 714  */
 715 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 716                                                  struct btrfs_fs_info *info,
 717                                                  u64 bytenr)
 718 {
 719         return block_group_cache_tree_search(info, bytenr, 1);
 720 }
 721
 722 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 723                                                   u64 flags)
 724 {
 725         struct list_head *head = &info->space_info;
 726         struct btrfs_space_info *found;
 727
 728         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 729
 730         rcu_read_lock();
 731         list_for_each_entry_rcu(found, head, list) {
 732                 if (found->flags & flags) {
 733                         rcu_read_unlock();
 734                         return found;
 735                 }
 736         }
 737         rcu_read_unlock();
 738         return NULL;
 739 }
 740
 741 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 742                              bool metadata, u64 root_objectid)
 743 {
 744         struct btrfs_space_info *space_info;
 745         u64 flags;
 746
 747         if (metadata) {
 748                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 749                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 750                 else
 751                         flags = BTRFS_BLOCK_GROUP_METADATA;
 752         } else {
 753                 flags = BTRFS_BLOCK_GROUP_DATA;
 754         }
 755
 756         space_info = __find_space_info(fs_info, flags);
 757         ASSERT(space_info);
 758         percpu_counter_add_batch(&space_info->total_bytes_pinned, num_bytes,
 759                     BTRFS_TOTAL_BYTES_PINNED_BATCH);
 760 }
 761
 762 /*
 763  * after adding space to the filesystem, we need to clear the full flags
 764  * on all the space infos.
 765  */
 766 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 767 {
 768         struct list_head *head = &info->space_info;
 769         struct btrfs_space_info *found;
 770
 771         rcu_read_lock();
 772         list_for_each_entry_rcu(found, head, list)
 773                 found->full = 0;
 774         rcu_read_unlock();
 775 }
 776
 777 /* simple helper to search for an existing data extent at a given offset */
 778 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 779 {
 780         int ret;
 781         struct btrfs_key key;
 782         struct btrfs_path *path;
 783
 784         path = btrfs_alloc_path();
 785         if (!path)
 786                 return -ENOMEM;
 787
 788         key.objectid = start;
 789         key.offset = len;
 790         key.type = BTRFS_EXTENT_ITEM_KEY;
 791         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 792         btrfs_free_path(path);
 793         return ret;
 794 }
 795
 796 /*
 797  * helper function to lookup reference count and flags of a tree block.
 798  *
 799  * the head node for delayed ref is used to store the sum of all the
 800  * reference count modifications queued up in the rbtree. the head
 801  * node may also store the extent flags to set. This way you can check
 802  * to see what the reference count and extent flags would be if all of
 803  * the delayed refs are not processed.
 804  */
 805 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 806                              struct btrfs_fs_info *fs_info, u64 bytenr,
 807                              u64 offset, int metadata, u64 *refs, u64 *flags)
 808 {
 809         struct btrfs_delayed_ref_head *head;
 810         struct btrfs_delayed_ref_root *delayed_refs;
 811         struct btrfs_path *path;
 812         struct btrfs_extent_item *ei;
 813         struct extent_buffer *leaf;
 814         struct btrfs_key key;
 815         u32 item_size;
 816         u64 num_refs;
 817         u64 extent_flags;
 818         int ret;
 819
 820         /*
 821          * If we don't have skinny metadata, don't bother doing anything
 822          * different
 823          */
 824         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 825                 offset = fs_info->nodesize;
 826                 metadata = 0;
 827         }
 828
 829         path = btrfs_alloc_path();
 830         if (!path)
 831                 return -ENOMEM;
 832
 833         if (!trans) {
 834                 path->skip_locking = 1;
 835                 path->search_commit_root = 1;
 836         }
 837
 838 search_again:
 839         key.objectid = bytenr;
 840         key.offset = offset;
 841         if (metadata)
 842                 key.type = BTRFS_METADATA_ITEM_KEY;
 843         else
 844                 key.type = BTRFS_EXTENT_ITEM_KEY;
 845
 846         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 847         if (ret < 0)
 848                 goto out_free;
 849
 850         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 851                 if (path->slots[0]) {
 852                         path->slots[0]--;
 853                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 854                                               path->slots[0]);
 855                         if (key.objectid == bytenr &&
 856                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 857                             key.offset == fs_info->nodesize)
 858                                 ret = 0;
 859                 }
 860         }
 861
 862         if (ret == 0) {
 863                 leaf = path->nodes[0];
 864                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 865                 if (item_size >= sizeof(*ei)) {
 866                         ei = btrfs_item_ptr(leaf, path->slots[0],
 867                                             struct btrfs_extent_item);
 868                         num_refs = btrfs_extent_refs(leaf, ei);
 869                         extent_flags = btrfs_extent_flags(leaf, ei);
 870                 } else {
 871                         ret = -EINVAL;
 872                         btrfs_print_v0_err(fs_info);
 873                         if (trans)
 874                                 btrfs_abort_transaction(trans, ret);
 875                         else
 876                                 btrfs_handle_fs_error(fs_info, ret, NULL);
 877
 878                         goto out_free;
 879                 }
 880
 881                 BUG_ON(num_refs == 0);
 882         } else {
 883                 num_refs = 0;
 884                 extent_flags = 0;
 885                 ret = 0;
 886         }
 887
 888         if (!trans)
 889                 goto out;
 890
 891         delayed_refs = &trans->transaction->delayed_refs;
 892         spin_lock(&delayed_refs->lock);
 893         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 894         if (head) {
 895                 if (!mutex_trylock(&head->mutex)) {
 896                         refcount_inc(&head->refs);
 897                         spin_unlock(&delayed_refs->lock);
 898
 899                         btrfs_release_path(path);
 900
 901                         /*
 902                          * Mutex was contended, block until it's released and try
 903                          * again
 904                          */
 905                         mutex_lock(&head->mutex);
 906                         mutex_unlock(&head->mutex);
 907                         btrfs_put_delayed_ref_head(head);
 908                         goto search_again;
 909                 }
 910                 spin_lock(&head->lock);
 911                 if (head->extent_op && head->extent_op->update_flags)
 912                         extent_flags |= head->extent_op->flags_to_set;
 913                 else
 914                         BUG_ON(num_refs == 0);
 915
 916                 num_refs += head->ref_mod;
 917                 spin_unlock(&head->lock);
 918                 mutex_unlock(&head->mutex);
 919         }
 920         spin_unlock(&delayed_refs->lock);
 921 out:
 922         WARN_ON(num_refs == 0);
 923         if (refs)
 924                 *refs = num_refs;
 925         if (flags)
 926                 *flags = extent_flags;
 927 out_free:
 928         btrfs_free_path(path);
 929         return ret;
 930 }
 931
 932 /*
 933  * Back reference rules.  Back refs have three main goals:
 934  *
 935  * 1) differentiate between all holders of references to an extent so that
 936  *    when a reference is dropped we can make sure it was a valid reference
 937  *    before freeing the extent.
 938  *
 939  * 2) Provide enough information to quickly find the holders of an extent
 940  *    if we notice a given block is corrupted or bad.
 941  *
 942  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 943  *    maintenance.  This is actually the same as #2, but with a slightly
 944  *    different use case.
 945  *
 946  * There are two kinds of back refs. The implicit back refs is optimized
 947  * for pointers in non-shared tree blocks. For a given pointer in a block,
 948  * back refs of this kind provide information about the block's owner tree
 949  * and the pointer's key. These information allow us to find the block by
 950  * b-tree searching. The full back refs is for pointers in tree blocks not
 951  * referenced by their owner trees. The location of tree block is recorded
 952  * in the back refs. Actually the full back refs is generic, and can be
 953  * used in all cases the implicit back refs is used. The major shortcoming
 954  * of the full back refs is its overhead. Every time a tree block gets
 955  * COWed, we have to update back refs entry for all pointers in it.
 956  *
 957  * For a newly allocated tree block, we use implicit back refs for
 958  * pointers in it. This means most tree related operations only involve
 959  * implicit back refs. For a tree block created in old transaction, the
 960  * only way to drop a reference to it is COW it. So we can detect the
 961  * event that tree block loses its owner tree's reference and do the
 962  * back refs conversion.
 963  *
 964  * When a tree block is COWed through a tree, there are four cases:
 965  *
 966  * The reference count of the block is one and the tree is the block's
 967  * owner tree. Nothing to do in this case.
 968  *
 969  * The reference count of the block is one and the tree is not the
 970  * block's owner tree. In this case, full back refs is used for pointers
 971  * in the block. Remove these full back refs, add implicit back refs for
 972  * every pointers in the new block.
 973  *
 974  * The reference count of the block is greater than one and the tree is
 975  * the block's owner tree. In this case, implicit back refs is used for
 976  * pointers in the block. Add full back refs for every pointers in the
 977  * block, increase lower level extents' reference counts. The original
 978  * implicit back refs are entailed to the new block.
 979  *
 980  * The reference count of the block is greater than one and the tree is
 981  * not the block's owner tree. Add implicit back refs for every pointer in
 982  * the new block, increase lower level extents' reference count.
 983  *
 984  * Back Reference Key composing:
 985  *
 986  * The key objectid corresponds to the first byte in the extent,
 987  * The key type is used to differentiate between types of back refs.
 988  * There are different meanings of the key offset for different types
 989  * of back refs.
 990  *
 991  * File extents can be referenced by:
 992  *
 993  * - multiple snapshots, subvolumes, or different generations in one subvol
 994  * - different files inside a single subvolume
 995  * - different offsets inside a file (bookend extents in file.c)
 996  *
 997  * The extent ref structure for the implicit back refs has fields for:
 998  *
 999  * - Objectid of the subvolume root
1000  * - objectid of the file holding the reference
1001  * - original offset in the file
1002  * - how many bookend extents
1003  *
1004  * The key offset for the implicit back refs is hash of the first
1005  * three fields.
1006  *
1007  * The extent ref structure for the full back refs has field for:
1008  *
1009  * - number of pointers in the tree leaf
1010  *
1011  * The key offset for the implicit back refs is the first byte of
1012  * the tree leaf
1013  *
1014  * When a file extent is allocated, The implicit back refs is used.
1015  * the fields are filled in:
1016  *
1017  *     (root_key.objectid, inode objectid, offset in file, 1)
1018  *
1019  * When a file extent is removed file truncation, we find the
1020  * corresponding implicit back refs and check the following fields:
1021  *
1022  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1023  *
1024  * Btree extents can be referenced by:
1025  *
1026  * - Different subvolumes
1027  *
1028  * Both the implicit back refs and the full back refs for tree blocks
1029  * only consist of key. The key offset for the implicit back refs is
1030  * objectid of block's owner tree. The key offset for the full back refs
1031  * is the first byte of parent block.
1032  *
1033  * When implicit back refs is used, information about the lowest key and
1034  * level of the tree block are required. These information are stored in
1035  * tree block info structure.
1036  */
1037
1038 /*
1039  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1040  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1041  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1042  */
1043 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1044                                      struct btrfs_extent_inline_ref *iref,
1045                                      enum btrfs_inline_ref_type is_data)
1046 {
1047         int type = btrfs_extent_inline_ref_type(eb, iref);
1048         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1049
1050         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1051             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1052             type == BTRFS_SHARED_DATA_REF_KEY ||
1053             type == BTRFS_EXTENT_DATA_REF_KEY) {
1054                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1055                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1056                                 return type;
1057                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1058                                 ASSERT(eb->fs_info);
1059                                 /*
1060                                  * Every shared one has parent tree
1061                                  * block, which must be aligned to
1062                                  * nodesize.
1063                                  */
1064                                 if (offset &&
1065                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1066                                         return type;
1067                         }
1068                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1069                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1070                                 return type;
1071                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1072                                 ASSERT(eb->fs_info);
1073                                 /*
1074                                  * Every shared one has parent tree
1075                                  * block, which must be aligned to
1076                                  * nodesize.
1077                                  */
1078                                 if (offset &&
1079                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1080                                         return type;
1081                         }
1082                 } else {
1083                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1084                         return type;
1085                 }
1086         }
1087
1088         btrfs_print_leaf((struct extent_buffer *)eb);
1089         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1090                   eb->start, type);
1091         WARN_ON(1);
1092
1093         return BTRFS_REF_TYPE_INVALID;
1094 }
1095
1096 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1097 {
1098         u32 high_crc = ~(u32)0;
1099         u32 low_crc = ~(u32)0;
1100         __le64 lenum;
1101
1102         lenum = cpu_to_le64(root_objectid);
1103         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1104         lenum = cpu_to_le64(owner);
1105         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1106         lenum = cpu_to_le64(offset);
1107         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1108
1109         return ((u64)high_crc << 31) ^ (u64)low_crc;
1110 }
1111
1112 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1113                                      struct btrfs_extent_data_ref *ref)
1114 {
1115         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1116                                     btrfs_extent_data_ref_objectid(leaf, ref),
1117                                     btrfs_extent_data_ref_offset(leaf, ref));
1118 }
1119
1120 static int match_extent_data_ref(struct extent_buffer *leaf,
1121                                  struct btrfs_extent_data_ref *ref,
1122                                  u64 root_objectid, u64 owner, u64 offset)
1123 {
1124         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1125             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1126             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1127                 return 0;
1128         return 1;
1129 }
1130
1131 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1132                                            struct btrfs_path *path,
1133                                            u64 bytenr, u64 parent,
1134                                            u64 root_objectid,
1135                                            u64 owner, u64 offset)
1136 {
1137         struct btrfs_root *root = trans->fs_info->extent_root;
1138         struct btrfs_key key;
1139         struct btrfs_extent_data_ref *ref;
1140         struct extent_buffer *leaf;
1141         u32 nritems;
1142         int ret;
1143         int recow;
1144         int err = -ENOENT;
1145
1146         key.objectid = bytenr;
1147         if (parent) {
1148                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1149                 key.offset = parent;
1150         } else {
1151                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1152                 key.offset = hash_extent_data_ref(root_objectid,
1153                                                   owner, offset);
1154         }
1155 again:
1156         recow = 0;
1157         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1158         if (ret < 0) {
1159                 err = ret;
1160                 goto fail;
1161         }
1162
1163         if (parent) {
1164                 if (!ret)
1165                         return 0;
1166                 goto fail;
1167         }
1168
1169         leaf = path->nodes[0];
1170         nritems = btrfs_header_nritems(leaf);
1171         while (1) {
1172                 if (path->slots[0] >= nritems) {
1173                         ret = btrfs_next_leaf(root, path);
1174                         if (ret < 0)
1175                                 err = ret;
1176                         if (ret)
1177                                 goto fail;
1178
1179                         leaf = path->nodes[0];
1180                         nritems = btrfs_header_nritems(leaf);
1181                         recow = 1;
1182                 }
1183
1184                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1185                 if (key.objectid != bytenr ||
1186                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1187                         goto fail;
1188
1189                 ref = btrfs_item_ptr(leaf, path->slots[0],
1190                                      struct btrfs_extent_data_ref);
1191
1192                 if (match_extent_data_ref(leaf, ref, root_objectid,
1193                                           owner, offset)) {
1194                         if (recow) {
1195                                 btrfs_release_path(path);
1196                                 goto again;
1197                         }
1198                         err = 0;
1199                         break;
1200                 }
1201                 path->slots[0]++;
1202         }
1203 fail:
1204         return err;
1205 }
1206
1207 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1208                                            struct btrfs_path *path,
1209                                            u64 bytenr, u64 parent,
1210                                            u64 root_objectid, u64 owner,
1211                                            u64 offset, int refs_to_add)
1212 {
1213         struct btrfs_root *root = trans->fs_info->extent_root;
1214         struct btrfs_key key;
1215         struct extent_buffer *leaf;
1216         u32 size;
1217         u32 num_refs;
1218         int ret;
1219
1220         key.objectid = bytenr;
1221         if (parent) {
1222                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1223                 key.offset = parent;
1224                 size = sizeof(struct btrfs_shared_data_ref);
1225         } else {
1226                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1227                 key.offset = hash_extent_data_ref(root_objectid,
1228                                                   owner, offset);
1229                 size = sizeof(struct btrfs_extent_data_ref);
1230         }
1231
1232         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1233         if (ret && ret != -EEXIST)
1234                 goto fail;
1235
1236         leaf = path->nodes[0];
1237         if (parent) {
1238                 struct btrfs_shared_data_ref *ref;
1239                 ref = btrfs_item_ptr(leaf, path->slots[0],
1240                                      struct btrfs_shared_data_ref);
1241                 if (ret == 0) {
1242                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1243                 } else {
1244                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1245                         num_refs += refs_to_add;
1246                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1247                 }
1248         } else {
1249                 struct btrfs_extent_data_ref *ref;
1250                 while (ret == -EEXIST) {
1251                         ref = btrfs_item_ptr(leaf, path->slots[0],
1252                                              struct btrfs_extent_data_ref);
1253                         if (match_extent_data_ref(leaf, ref, root_objectid,
1254                                                   owner, offset))
1255                                 break;
1256                         btrfs_release_path(path);
1257                         key.offset++;
1258                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1259                                                       size);
1260                         if (ret && ret != -EEXIST)
1261                                 goto fail;
1262
1263                         leaf = path->nodes[0];
1264                 }
1265                 ref = btrfs_item_ptr(leaf, path->slots[0],
1266                                      struct btrfs_extent_data_ref);
1267                 if (ret == 0) {
1268                         btrfs_set_extent_data_ref_root(leaf, ref,
1269                                                        root_objectid);
1270                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1271                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1272                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1273                 } else {
1274                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1275                         num_refs += refs_to_add;
1276                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1277                 }
1278         }
1279         btrfs_mark_buffer_dirty(leaf);
1280         ret = 0;
1281 fail:
1282         btrfs_release_path(path);
1283         return ret;
1284 }
1285
1286 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1287                                            struct btrfs_path *path,
1288                                            int refs_to_drop, int *last_ref)
1289 {
1290         struct btrfs_key key;
1291         struct btrfs_extent_data_ref *ref1 = NULL;
1292         struct btrfs_shared_data_ref *ref2 = NULL;
1293         struct extent_buffer *leaf;
1294         u32 num_refs = 0;
1295         int ret = 0;
1296
1297         leaf = path->nodes[0];
1298         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1299
1300         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1301                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1302                                       struct btrfs_extent_data_ref);
1303                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1304         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1305                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1306                                       struct btrfs_shared_data_ref);
1307                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1308         } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
1309                 btrfs_print_v0_err(trans->fs_info);
1310                 btrfs_abort_transaction(trans, -EINVAL);
1311                 return -EINVAL;
1312         } else {
1313                 BUG();
1314         }
1315
1316         BUG_ON(num_refs < refs_to_drop);
1317         num_refs -= refs_to_drop;
1318
1319         if (num_refs == 0) {
1320                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1321                 *last_ref = 1;
1322         } else {
1323                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1324                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1325                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1326                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1327                 btrfs_mark_buffer_dirty(leaf);
1328         }
1329         return ret;
1330 }
1331
1332 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1333                                           struct btrfs_extent_inline_ref *iref)
1334 {
1335         struct btrfs_key key;
1336         struct extent_buffer *leaf;
1337         struct btrfs_extent_data_ref *ref1;
1338         struct btrfs_shared_data_ref *ref2;
1339         u32 num_refs = 0;
1340         int type;
1341
1342         leaf = path->nodes[0];
1343         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1344
1345         BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
1346         if (iref) {
1347                 /*
1348                  * If type is invalid, we should have bailed out earlier than
1349                  * this call.
1350                  */
1351                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1352                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1353                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1354                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1355                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1356                 } else {
1357                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1358                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1359                 }
1360         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1361                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1362                                       struct btrfs_extent_data_ref);
1363                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1364         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1365                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1366                                       struct btrfs_shared_data_ref);
1367                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1368         } else {
1369                 WARN_ON(1);
1370         }
1371         return num_refs;
1372 }
1373
1374 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1375                                           struct btrfs_path *path,
1376                                           u64 bytenr, u64 parent,
1377                                           u64 root_objectid)
1378 {
1379         struct btrfs_root *root = trans->fs_info->extent_root;
1380         struct btrfs_key key;
1381         int ret;
1382
1383         key.objectid = bytenr;
1384         if (parent) {
1385                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1386                 key.offset = parent;
1387         } else {
1388                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1389                 key.offset = root_objectid;
1390         }
1391
1392         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1393         if (ret > 0)
1394                 ret = -ENOENT;
1395         return ret;
1396 }
1397
1398 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1399                                           struct btrfs_path *path,
1400                                           u64 bytenr, u64 parent,
1401                                           u64 root_objectid)
1402 {
1403         struct btrfs_key key;
1404         int ret;
1405
1406         key.objectid = bytenr;
1407         if (parent) {
1408                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1409                 key.offset = parent;
1410         } else {
1411                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1412                 key.offset = root_objectid;
1413         }
1414
1415         ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
1416                                       path, &key, 0);
1417         btrfs_release_path(path);
1418         return ret;
1419 }
1420
1421 static inline int extent_ref_type(u64 parent, u64 owner)
1422 {
1423         int type;
1424         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1425                 if (parent > 0)
1426                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1427                 else
1428                         type = BTRFS_TREE_BLOCK_REF_KEY;
1429         } else {
1430                 if (parent > 0)
1431                         type = BTRFS_SHARED_DATA_REF_KEY;
1432                 else
1433                         type = BTRFS_EXTENT_DATA_REF_KEY;
1434         }
1435         return type;
1436 }
1437
1438 static int find_next_key(struct btrfs_path *path, int level,
1439                          struct btrfs_key *key)
1440
1441 {
1442         for (; level < BTRFS_MAX_LEVEL; level++) {
1443                 if (!path->nodes[level])
1444                         break;
1445                 if (path->slots[level] + 1 >=
1446                     btrfs_header_nritems(path->nodes[level]))
1447                         continue;
1448                 if (level == 0)
1449                         btrfs_item_key_to_cpu(path->nodes[level], key,
1450                                               path->slots[level] + 1);
1451                 else
1452                         btrfs_node_key_to_cpu(path->nodes[level], key,
1453                                               path->slots[level] + 1);
1454                 return 0;
1455         }
1456         return 1;
1457 }
1458
1459 /*
1460  * look for inline back ref. if back ref is found, *ref_ret is set
1461  * to the address of inline back ref, and 0 is returned.
1462  *
1463  * if back ref isn't found, *ref_ret is set to the address where it
1464  * should be inserted, and -ENOENT is returned.
1465  *
1466  * if insert is true and there are too many inline back refs, the path
1467  * points to the extent item, and -EAGAIN is returned.
1468  *
1469  * NOTE: inline back refs are ordered in the same way that back ref
1470  *       items in the tree are ordered.
1471  */
1472 static noinline_for_stack
1473 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1474                                  struct btrfs_path *path,
1475                                  struct btrfs_extent_inline_ref **ref_ret,
1476                                  u64 bytenr, u64 num_bytes,
1477                                  u64 parent, u64 root_objectid,
1478                                  u64 owner, u64 offset, int insert)
1479 {
1480         struct btrfs_fs_info *fs_info = trans->fs_info;
1481         struct btrfs_root *root = fs_info->extent_root;
1482         struct btrfs_key key;
1483         struct extent_buffer *leaf;
1484         struct btrfs_extent_item *ei;
1485         struct btrfs_extent_inline_ref *iref;
1486         u64 flags;
1487         u64 item_size;
1488         unsigned long ptr;
1489         unsigned long end;
1490         int extra_size;
1491         int type;
1492         int want;
1493         int ret;
1494         int err = 0;
1495         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1496         int needed;
1497
1498         key.objectid = bytenr;
1499         key.type = BTRFS_EXTENT_ITEM_KEY;
1500         key.offset = num_bytes;
1501
1502         want = extent_ref_type(parent, owner);
1503         if (insert) {
1504                 extra_size = btrfs_extent_inline_ref_size(want);
1505                 path->keep_locks = 1;
1506         } else
1507                 extra_size = -1;
1508
1509         /*
1510          * Owner is our level, so we can just add one to get the level for the
1511          * block we are interested in.
1512          */
1513         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1514                 key.type = BTRFS_METADATA_ITEM_KEY;
1515                 key.offset = owner;
1516         }
1517
1518 again:
1519         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1520         if (ret < 0) {
1521                 err = ret;
1522                 goto out;
1523         }
1524
1525         /*
1526          * We may be a newly converted file system which still has the old fat
1527          * extent entries for metadata, so try and see if we have one of those.
1528          */
1529         if (ret > 0 && skinny_metadata) {
1530                 skinny_metadata = false;
1531                 if (path->slots[0]) {
1532                         path->slots[0]--;
1533                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1534                                               path->slots[0]);
1535                         if (key.objectid == bytenr &&
1536                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1537                             key.offset == num_bytes)
1538                                 ret = 0;
1539                 }
1540                 if (ret) {
1541                         key.objectid = bytenr;
1542                         key.type = BTRFS_EXTENT_ITEM_KEY;
1543                         key.offset = num_bytes;
1544                         btrfs_release_path(path);
1545                         goto again;
1546                 }
1547         }
1548
1549         if (ret && !insert) {
1550                 err = -ENOENT;
1551                 goto out;
1552         } else if (WARN_ON(ret)) {
1553                 err = -EIO;
1554                 goto out;
1555         }
1556
1557         leaf = path->nodes[0];
1558         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1559         if (unlikely(item_size < sizeof(*ei))) {
1560                 err = -EINVAL;
1561                 btrfs_print_v0_err(fs_info);
1562                 btrfs_abort_transaction(trans, err);
1563                 goto out;
1564         }
1565
1566         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1567         flags = btrfs_extent_flags(leaf, ei);
1568
1569         ptr = (unsigned long)(ei + 1);
1570         end = (unsigned long)ei + item_size;
1571
1572         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1573                 ptr += sizeof(struct btrfs_tree_block_info);
1574                 BUG_ON(ptr > end);
1575         }
1576
1577         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1578                 needed = BTRFS_REF_TYPE_DATA;
1579         else
1580                 needed = BTRFS_REF_TYPE_BLOCK;
1581
1582         err = -ENOENT;
1583         while (1) {
1584                 if (ptr >= end) {
1585                         WARN_ON(ptr > end);
1586                         break;
1587                 }
1588                 iref = (struct btrfs_extent_inline_ref *)ptr;
1589                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1590                 if (type == BTRFS_REF_TYPE_INVALID) {
1591                         err = -EUCLEAN;
1592                         goto out;
1593                 }
1594
1595                 if (want < type)
1596                         break;
1597                 if (want > type) {
1598                         ptr += btrfs_extent_inline_ref_size(type);
1599                         continue;
1600                 }
1601
1602                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1603                         struct btrfs_extent_data_ref *dref;
1604                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1605                         if (match_extent_data_ref(leaf, dref, root_objectid,
1606                                                   owner, offset)) {
1607                                 err = 0;
1608                                 break;
1609                         }
1610                         if (hash_extent_data_ref_item(leaf, dref) <
1611                             hash_extent_data_ref(root_objectid, owner, offset))
1612                                 break;
1613                 } else {
1614                         u64 ref_offset;
1615                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1616                         if (parent > 0) {
1617                                 if (parent == ref_offset) {
1618                                         err = 0;
1619                                         break;
1620                                 }
1621                                 if (ref_offset < parent)
1622                                         break;
1623                         } else {
1624                                 if (root_objectid == ref_offset) {
1625                                         err = 0;
1626                                         break;
1627                                 }
1628                                 if (ref_offset < root_objectid)
1629                                         break;
1630                         }
1631                 }
1632                 ptr += btrfs_extent_inline_ref_size(type);
1633         }
1634         if (err == -ENOENT && insert) {
1635                 if (item_size + extra_size >=
1636                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1637                         err = -EAGAIN;
1638                         goto out;
1639                 }
1640                 /*
1641                  * To add new inline back ref, we have to make sure
1642                  * there is no corresponding back ref item.
1643                  * For simplicity, we just do not add new inline back
1644                  * ref if there is any kind of item for this block
1645                  */
1646                 if (find_next_key(path, 0, &key) == 0 &&
1647                     key.objectid == bytenr &&
1648                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1649                         err = -EAGAIN;
1650                         goto out;
1651                 }
1652         }
1653         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1654 out:
1655         if (insert) {
1656                 path->keep_locks = 0;
1657                 btrfs_unlock_up_safe(path, 1);
1658         }
1659         return err;
1660 }
1661
1662 /*
1663  * helper to add new inline back ref
1664  */
1665 static noinline_for_stack
1666 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1667                                  struct btrfs_path *path,
1668                                  struct btrfs_extent_inline_ref *iref,
1669                                  u64 parent, u64 root_objectid,
1670                                  u64 owner, u64 offset, int refs_to_add,
1671                                  struct btrfs_delayed_extent_op *extent_op)
1672 {
1673         struct extent_buffer *leaf;
1674         struct btrfs_extent_item *ei;
1675         unsigned long ptr;
1676         unsigned long end;
1677         unsigned long item_offset;
1678         u64 refs;
1679         int size;
1680         int type;
1681
1682         leaf = path->nodes[0];
1683         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1684         item_offset = (unsigned long)iref - (unsigned long)ei;
1685
1686         type = extent_ref_type(parent, owner);
1687         size = btrfs_extent_inline_ref_size(type);
1688
1689         btrfs_extend_item(fs_info, path, size);
1690
1691         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1692         refs = btrfs_extent_refs(leaf, ei);
1693         refs += refs_to_add;
1694         btrfs_set_extent_refs(leaf, ei, refs);
1695         if (extent_op)
1696                 __run_delayed_extent_op(extent_op, leaf, ei);
1697
1698         ptr = (unsigned long)ei + item_offset;
1699         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1700         if (ptr < end - size)
1701                 memmove_extent_buffer(leaf, ptr + size, ptr,
1702                                       end - size - ptr);
1703
1704         iref = (struct btrfs_extent_inline_ref *)ptr;
1705         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1706         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1707                 struct btrfs_extent_data_ref *dref;
1708                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1709                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1710                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1711                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1712                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1713         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1714                 struct btrfs_shared_data_ref *sref;
1715                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1716                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1717                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1718         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1719                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1720         } else {
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1722         }
1723         btrfs_mark_buffer_dirty(leaf);
1724 }
1725
1726 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1727                                  struct btrfs_path *path,
1728                                  struct btrfs_extent_inline_ref **ref_ret,
1729                                  u64 bytenr, u64 num_bytes, u64 parent,
1730                                  u64 root_objectid, u64 owner, u64 offset)
1731 {
1732         int ret;
1733
1734         ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1735                                            num_bytes, parent, root_objectid,
1736                                            owner, offset, 0);
1737         if (ret != -ENOENT)
1738                 return ret;
1739
1740         btrfs_release_path(path);
1741         *ref_ret = NULL;
1742
1743         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1744                 ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1745                                             root_objectid);
1746         } else {
1747                 ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1748                                              root_objectid, owner, offset);
1749         }
1750         return ret;
1751 }
1752
1753 /*
1754  * helper to update/remove inline back ref
1755  */
1756 static noinline_for_stack
1757 void update_inline_extent_backref(struct btrfs_path *path,
1758                                   struct btrfs_extent_inline_ref *iref,
1759                                   int refs_to_mod,
1760                                   struct btrfs_delayed_extent_op *extent_op,
1761                                   int *last_ref)
1762 {
1763         struct extent_buffer *leaf = path->nodes[0];
1764         struct btrfs_fs_info *fs_info = leaf->fs_info;
1765         struct btrfs_extent_item *ei;
1766         struct btrfs_extent_data_ref *dref = NULL;
1767         struct btrfs_shared_data_ref *sref = NULL;
1768         unsigned long ptr;
1769         unsigned long end;
1770         u32 item_size;
1771         int size;
1772         int type;
1773         u64 refs;
1774
1775         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1776         refs = btrfs_extent_refs(leaf, ei);
1777         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1778         refs += refs_to_mod;
1779         btrfs_set_extent_refs(leaf, ei, refs);
1780         if (extent_op)
1781                 __run_delayed_extent_op(extent_op, leaf, ei);
1782
1783         /*
1784          * If type is invalid, we should have bailed out after
1785          * lookup_inline_extent_backref().
1786          */
1787         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1788         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 *last_ref = 1;
1811                 size =  btrfs_extent_inline_ref_size(type);
1812                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1813                 ptr = (unsigned long)iref;
1814                 end = (unsigned long)ei + item_size;
1815                 if (ptr + size < end)
1816                         memmove_extent_buffer(leaf, ptr, ptr + size,
1817                                               end - ptr - size);
1818                 item_size -= size;
1819                 btrfs_truncate_item(fs_info, path, item_size, 1);
1820         }
1821         btrfs_mark_buffer_dirty(leaf);
1822 }
1823
1824 static noinline_for_stack
1825 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1836                                            num_bytes, parent, root_objectid,
1837                                            owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(path, iref, refs_to_add,
1841                                              extent_op, NULL);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_path *path,
1853                                  u64 bytenr, u64 parent, u64 root_objectid,
1854                                  u64 owner, u64 offset, int refs_to_add)
1855 {
1856         int ret;
1857         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1858                 BUG_ON(refs_to_add != 1);
1859                 ret = insert_tree_block_ref(trans, path, bytenr, parent,
1860                                             root_objectid);
1861         } else {
1862                 ret = insert_extent_data_ref(trans, path, bytenr, parent,
1863                                              root_objectid, owner, offset,
1864                                              refs_to_add);
1865         }
1866         return ret;
1867 }
1868
1869 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1870                                  struct btrfs_path *path,
1871                                  struct btrfs_extent_inline_ref *iref,
1872                                  int refs_to_drop, int is_data, int *last_ref)
1873 {
1874         int ret = 0;
1875
1876         BUG_ON(!is_data && refs_to_drop != 1);
1877         if (iref) {
1878                 update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
1879                                              last_ref);
1880         } else if (is_data) {
1881                 ret = remove_extent_data_ref(trans, path, refs_to_drop,
1882                                              last_ref);
1883         } else {
1884                 *last_ref = 1;
1885                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1886         }
1887         return ret;
1888 }
1889
1890 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1891 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1892                                u64 *discarded_bytes)
1893 {
1894         int j, ret = 0;
1895         u64 bytes_left, end;
1896         u64 aligned_start = ALIGN(start, 1 << 9);
1897
1898         if (WARN_ON(start != aligned_start)) {
1899                 len -= aligned_start - start;
1900                 len = round_down(len, 1 << 9);
1901                 start = aligned_start;
1902         }
1903
1904         *discarded_bytes = 0;
1905
1906         if (!len)
1907                 return 0;
1908
1909         end = start + len;
1910         bytes_left = len;
1911
1912         /* Skip any superblocks on this device. */
1913         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1914                 u64 sb_start = btrfs_sb_offset(j);
1915                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1916                 u64 size = sb_start - start;
1917
1918                 if (!in_range(sb_start, start, bytes_left) &&
1919                     !in_range(sb_end, start, bytes_left) &&
1920                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1921                         continue;
1922
1923                 /*
1924                  * Superblock spans beginning of range.  Adjust start and
1925                  * try again.
1926                  */
1927                 if (sb_start <= start) {
1928                         start += sb_end - start;
1929                         if (start > end) {
1930                                 bytes_left = 0;
1931                                 break;
1932                         }
1933                         bytes_left = end - start;
1934                         continue;
1935                 }
1936
1937                 if (size) {
1938                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1939                                                    GFP_NOFS, 0);
1940                         if (!ret)
1941                                 *discarded_bytes += size;
1942                         else if (ret != -EOPNOTSUPP)
1943                                 return ret;
1944                 }
1945
1946                 start = sb_end;
1947                 if (start > end) {
1948                         bytes_left = 0;
1949                         break;
1950                 }
1951                 bytes_left = end - start;
1952         }
1953
1954         if (bytes_left) {
1955                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1956                                            GFP_NOFS, 0);
1957                 if (!ret)
1958                         *discarded_bytes += bytes_left;
1959         }
1960         return ret;
1961 }
1962
1963 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1964                          u64 num_bytes, u64 *actual_bytes)
1965 {
1966         int ret;
1967         u64 discarded_bytes = 0;
1968         struct btrfs_bio *bbio = NULL;
1969
1970
1971         /*
1972          * Avoid races with device replace and make sure our bbio has devices
1973          * associated to its stripes that don't go away while we are discarding.
1974          */
1975         btrfs_bio_counter_inc_blocked(fs_info);
1976         /* Tell the block device(s) that the sectors can be discarded */
1977         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
1978                               &bbio, 0);
1979         /* Error condition is -ENOMEM */
1980         if (!ret) {
1981                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1982                 int i;
1983
1984
1985                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1986                         u64 bytes;
1987                         struct request_queue *req_q;
1988
1989                         if (!stripe->dev->bdev) {
1990                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1991                                 continue;
1992                         }
1993                         req_q = bdev_get_queue(stripe->dev->bdev);
1994                         if (!blk_queue_discard(req_q))
1995                                 continue;
1996
1997                         ret = btrfs_issue_discard(stripe->dev->bdev,
1998                                                   stripe->physical,
1999                                                   stripe->length,
2000                                                   &bytes);
2001                         if (!ret)
2002                                 discarded_bytes += bytes;
2003                         else if (ret != -EOPNOTSUPP)
2004                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2005
2006                         /*
2007                          * Just in case we get back EOPNOTSUPP for some reason,
2008                          * just ignore the return value so we don't screw up
2009                          * people calling discard_extent.
2010                          */
2011                         ret = 0;
2012                 }
2013                 btrfs_put_bbio(bbio);
2014         }
2015         btrfs_bio_counter_dec(fs_info);
2016
2017         if (actual_bytes)
2018                 *actual_bytes = discarded_bytes;
2019
2020
2021         if (ret == -EOPNOTSUPP)
2022                 ret = 0;
2023         return ret;
2024 }
2025
2026 /* Can return -ENOMEM */
2027 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2028                          struct btrfs_root *root,
2029                          u64 bytenr, u64 num_bytes, u64 parent,
2030                          u64 root_objectid, u64 owner, u64 offset)
2031 {
2032         struct btrfs_fs_info *fs_info = root->fs_info;
2033         int old_ref_mod, new_ref_mod;
2034         int ret;
2035
2036         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2037                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2038
2039         btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
2040                            owner, offset, BTRFS_ADD_DELAYED_REF);
2041
2042         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2043                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
2044                                                  num_bytes, parent,
2045                                                  root_objectid, (int)owner,
2046                                                  BTRFS_ADD_DELAYED_REF, NULL,
2047                                                  &old_ref_mod, &new_ref_mod);
2048         } else {
2049                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
2050                                                  num_bytes, parent,
2051                                                  root_objectid, owner, offset,
2052                                                  0, BTRFS_ADD_DELAYED_REF,
2053                                                  &old_ref_mod, &new_ref_mod);
2054         }
2055
2056         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0) {
2057                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
2058
2059                 add_pinned_bytes(fs_info, -num_bytes, metadata, root_objectid);
2060         }
2061
2062         return ret;
2063 }
2064
2065 /*
2066  * __btrfs_inc_extent_ref - insert backreference for a given extent
2067  *
2068  * @trans:          Handle of transaction
2069  *
2070  * @node:           The delayed ref node used to get the bytenr/length for
2071  *                  extent whose references are incremented.
2072  *
2073  * @parent:         If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
2074  *                  BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
2075  *                  bytenr of the parent block. Since new extents are always
2076  *                  created with indirect references, this will only be the case
2077  *                  when relocating a shared extent. In that case, root_objectid
2078  *                  will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
2079  *                  be 0
2080  *
2081  * @root_objectid:  The id of the root where this modification has originated,
2082  *                  this can be either one of the well-known metadata trees or
2083  *                  the subvolume id which references this extent.
2084  *
2085  * @owner:          For data extents it is the inode number of the owning file.
2086  *                  For metadata extents this parameter holds the level in the
2087  *                  tree of the extent.
2088  *
2089  * @offset:         For metadata extents the offset is ignored and is currently
2090  *                  always passed as 0. For data extents it is the fileoffset
2091  *                  this extent belongs to.
2092  *
2093  * @refs_to_add     Number of references to add
2094  *
2095  * @extent_op       Pointer to a structure, holding information necessary when
2096  *                  updating a tree block's flags
2097  *
2098  */
2099 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2100                                   struct btrfs_delayed_ref_node *node,
2101                                   u64 parent, u64 root_objectid,
2102                                   u64 owner, u64 offset, int refs_to_add,
2103                                   struct btrfs_delayed_extent_op *extent_op)
2104 {
2105         struct btrfs_path *path;
2106         struct extent_buffer *leaf;
2107         struct btrfs_extent_item *item;
2108         struct btrfs_key key;
2109         u64 bytenr = node->bytenr;
2110         u64 num_bytes = node->num_bytes;
2111         u64 refs;
2112         int ret;
2113
2114         path = btrfs_alloc_path();
2115         if (!path)
2116                 return -ENOMEM;
2117
2118         path->reada = READA_FORWARD;
2119         path->leave_spinning = 1;
2120         /* this will setup the path even if it fails to insert the back ref */
2121         ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
2122                                            parent, root_objectid, owner,
2123                                            offset, refs_to_add, extent_op);
2124         if ((ret < 0 && ret != -EAGAIN) || !ret)
2125                 goto out;
2126
2127         /*
2128          * Ok we had -EAGAIN which means we didn't have space to insert and
2129          * inline extent ref, so just update the reference count and add a
2130          * normal backref.
2131          */
2132         leaf = path->nodes[0];
2133         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2134         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2135         refs = btrfs_extent_refs(leaf, item);
2136         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2137         if (extent_op)
2138                 __run_delayed_extent_op(extent_op, leaf, item);
2139
2140         btrfs_mark_buffer_dirty(leaf);
2141         btrfs_release_path(path);
2142
2143         path->reada = READA_FORWARD;
2144         path->leave_spinning = 1;
2145         /* now insert the actual backref */
2146         ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
2147                                     owner, offset, refs_to_add);
2148         if (ret)
2149                 btrfs_abort_transaction(trans, ret);
2150 out:
2151         btrfs_free_path(path);
2152         return ret;
2153 }
2154
2155 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2156                                 struct btrfs_delayed_ref_node *node,
2157                                 struct btrfs_delayed_extent_op *extent_op,
2158                                 int insert_reserved)
2159 {
2160         int ret = 0;
2161         struct btrfs_delayed_data_ref *ref;
2162         struct btrfs_key ins;
2163         u64 parent = 0;
2164         u64 ref_root = 0;
2165         u64 flags = 0;
2166
2167         ins.objectid = node->bytenr;
2168         ins.offset = node->num_bytes;
2169         ins.type = BTRFS_EXTENT_ITEM_KEY;
2170
2171         ref = btrfs_delayed_node_to_data_ref(node);
2172         trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
2173
2174         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2175                 parent = ref->parent;
2176         ref_root = ref->root;
2177
2178         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2179                 if (extent_op)
2180                         flags |= extent_op->flags_to_set;
2181                 ret = alloc_reserved_file_extent(trans, parent, ref_root,
2182                                                  flags, ref->objectid,
2183                                                  ref->offset, &ins,
2184                                                  node->ref_mod);
2185         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2186                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2187                                              ref->objectid, ref->offset,
2188                                              node->ref_mod, extent_op);
2189         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2190                 ret = __btrfs_free_extent(trans, node, parent,
2191                                           ref_root, ref->objectid,
2192                                           ref->offset, node->ref_mod,
2193                                           extent_op);
2194         } else {
2195                 BUG();
2196         }
2197         return ret;
2198 }
2199
2200 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2201                                     struct extent_buffer *leaf,
2202                                     struct btrfs_extent_item *ei)
2203 {
2204         u64 flags = btrfs_extent_flags(leaf, ei);
2205         if (extent_op->update_flags) {
2206                 flags |= extent_op->flags_to_set;
2207                 btrfs_set_extent_flags(leaf, ei, flags);
2208         }
2209
2210         if (extent_op->update_key) {
2211                 struct btrfs_tree_block_info *bi;
2212                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2213                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2214                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2215         }
2216 }
2217
2218 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2219                                  struct btrfs_delayed_ref_head *head,
2220                                  struct btrfs_delayed_extent_op *extent_op)
2221 {
2222         struct btrfs_fs_info *fs_info = trans->fs_info;
2223         struct btrfs_key key;
2224         struct btrfs_path *path;
2225         struct btrfs_extent_item *ei;
2226         struct extent_buffer *leaf;
2227         u32 item_size;
2228         int ret;
2229         int err = 0;
2230         int metadata = !extent_op->is_data;
2231
2232         if (trans->aborted)
2233                 return 0;
2234
2235         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2236                 metadata = 0;
2237
2238         path = btrfs_alloc_path();
2239         if (!path)
2240                 return -ENOMEM;
2241
2242         key.objectid = head->bytenr;
2243
2244         if (metadata) {
2245                 key.type = BTRFS_METADATA_ITEM_KEY;
2246                 key.offset = extent_op->level;
2247         } else {
2248                 key.type = BTRFS_EXTENT_ITEM_KEY;
2249                 key.offset = head->num_bytes;
2250         }
2251
2252 again:
2253         path->reada = READA_FORWARD;
2254         path->leave_spinning = 1;
2255         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2256         if (ret < 0) {
2257                 err = ret;
2258                 goto out;
2259         }
2260         if (ret > 0) {
2261                 if (metadata) {
2262                         if (path->slots[0] > 0) {
2263                                 path->slots[0]--;
2264                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2265                                                       path->slots[0]);
2266                                 if (key.objectid == head->bytenr &&
2267                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2268                                     key.offset == head->num_bytes)
2269                                         ret = 0;
2270                         }
2271                         if (ret > 0) {
2272                                 btrfs_release_path(path);
2273                                 metadata = 0;
2274
2275                                 key.objectid = head->bytenr;
2276                                 key.offset = head->num_bytes;
2277                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2278                                 goto again;
2279                         }
2280                 } else {
2281                         err = -EIO;
2282                         goto out;
2283                 }
2284         }
2285
2286         leaf = path->nodes[0];
2287         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2288
2289         if (unlikely(item_size < sizeof(*ei))) {
2290                 err = -EINVAL;
2291                 btrfs_print_v0_err(fs_info);
2292                 btrfs_abort_transaction(trans, err);
2293                 goto out;
2294         }
2295
2296         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2297         __run_delayed_extent_op(extent_op, leaf, ei);
2298
2299         btrfs_mark_buffer_dirty(leaf);
2300 out:
2301         btrfs_free_path(path);
2302         return err;
2303 }
2304
2305 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2306                                 struct btrfs_delayed_ref_node *node,
2307                                 struct btrfs_delayed_extent_op *extent_op,
2308                                 int insert_reserved)
2309 {
2310         int ret = 0;
2311         struct btrfs_delayed_tree_ref *ref;
2312         u64 parent = 0;
2313         u64 ref_root = 0;
2314
2315         ref = btrfs_delayed_node_to_tree_ref(node);
2316         trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
2317
2318         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2319                 parent = ref->parent;
2320         ref_root = ref->root;
2321
2322         if (node->ref_mod != 1) {
2323                 btrfs_err(trans->fs_info,
2324         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2325                           node->bytenr, node->ref_mod, node->action, ref_root,
2326                           parent);
2327                 return -EIO;
2328         }
2329         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2330                 BUG_ON(!extent_op || !extent_op->update_flags);
2331                 ret = alloc_reserved_tree_block(trans, node, extent_op);
2332         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2333                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2334                                              ref->level, 0, 1, extent_op);
2335         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2336                 ret = __btrfs_free_extent(trans, node, parent, ref_root,
2337                                           ref->level, 0, 1, extent_op);
2338         } else {
2339                 BUG();
2340         }
2341         return ret;
2342 }
2343
2344 /* helper function to actually process a single delayed ref entry */
2345 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2346                                struct btrfs_delayed_ref_node *node,
2347                                struct btrfs_delayed_extent_op *extent_op,
2348                                int insert_reserved)
2349 {
2350         int ret = 0;
2351
2352         if (trans->aborted) {
2353                 if (insert_reserved)
2354                         btrfs_pin_extent(trans->fs_info, node->bytenr,
2355                                          node->num_bytes, 1);
2356                 return 0;
2357         }
2358
2359         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2360             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2361                 ret = run_delayed_tree_ref(trans, node, extent_op,
2362                                            insert_reserved);
2363         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2364                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2365                 ret = run_delayed_data_ref(trans, node, extent_op,
2366                                            insert_reserved);
2367         else
2368                 BUG();
2369         if (ret && insert_reserved)
2370                 btrfs_pin_extent(trans->fs_info, node->bytenr,
2371                                  node->num_bytes, 1);
2372         return ret;
2373 }
2374
2375 static inline struct btrfs_delayed_ref_node *
2376 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2377 {
2378         struct btrfs_delayed_ref_node *ref;
2379
2380         if (RB_EMPTY_ROOT(&head->ref_tree))
2381                 return NULL;
2382
2383         /*
2384          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2385          * This is to prevent a ref count from going down to zero, which deletes
2386          * the extent item from the extent tree, when there still are references
2387          * to add, which would fail because they would not find the extent item.
2388          */
2389         if (!list_empty(&head->ref_add_list))
2390                 return list_first_entry(&head->ref_add_list,
2391                                 struct btrfs_delayed_ref_node, add_list);
2392
2393         ref = rb_entry(rb_first(&head->ref_tree),
2394                        struct btrfs_delayed_ref_node, ref_node);
2395         ASSERT(list_empty(&ref->add_list));
2396         return ref;
2397 }
2398
2399 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2400                                       struct btrfs_delayed_ref_head *head)
2401 {
2402         spin_lock(&delayed_refs->lock);
2403         head->processing = 0;
2404         delayed_refs->num_heads_ready++;
2405         spin_unlock(&delayed_refs->lock);
2406         btrfs_delayed_ref_unlock(head);
2407 }
2408
2409 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2410                              struct btrfs_delayed_ref_head *head)
2411 {
2412         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2413         int ret;
2414
2415         if (!extent_op)
2416                 return 0;
2417         head->extent_op = NULL;
2418         if (head->must_insert_reserved) {
2419                 btrfs_free_delayed_extent_op(extent_op);
2420                 return 0;
2421         }
2422         spin_unlock(&head->lock);
2423         ret = run_delayed_extent_op(trans, head, extent_op);
2424         btrfs_free_delayed_extent_op(extent_op);
2425         return ret ? ret : 1;
2426 }
2427
2428 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2429                             struct btrfs_delayed_ref_head *head)
2430 {
2431
2432         struct btrfs_fs_info *fs_info = trans->fs_info;
2433         struct btrfs_delayed_ref_root *delayed_refs;
2434         int ret;
2435
2436         delayed_refs = &trans->transaction->delayed_refs;
2437
2438         ret = cleanup_extent_op(trans, head);
2439         if (ret < 0) {
2440                 unselect_delayed_ref_head(delayed_refs, head);
2441                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2442                 return ret;
2443         } else if (ret) {
2444                 return ret;
2445         }
2446
2447         /*
2448          * Need to drop our head ref lock and re-acquire the delayed ref lock
2449          * and then re-check to make sure nobody got added.
2450          */
2451         spin_unlock(&head->lock);
2452         spin_lock(&delayed_refs->lock);
2453         spin_lock(&head->lock);
2454         if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) {
2455                 spin_unlock(&head->lock);
2456                 spin_unlock(&delayed_refs->lock);
2457                 return 1;
2458         }
2459         delayed_refs->num_heads--;
2460         rb_erase(&head->href_node, &delayed_refs->href_root);
2461         RB_CLEAR_NODE(&head->href_node);
2462         spin_unlock(&head->lock);
2463         spin_unlock(&delayed_refs->lock);
2464         atomic_dec(&delayed_refs->num_entries);
2465
2466         trace_run_delayed_ref_head(fs_info, head, 0);
2467
2468         if (head->total_ref_mod < 0) {
2469                 struct btrfs_space_info *space_info;
2470                 u64 flags;
2471
2472                 if (head->is_data)
2473                         flags = BTRFS_BLOCK_GROUP_DATA;
2474                 else if (head->is_system)
2475                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
2476                 else
2477                         flags = BTRFS_BLOCK_GROUP_METADATA;
2478                 space_info = __find_space_info(fs_info, flags);
2479                 ASSERT(space_info);
2480                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
2481                                    -head->num_bytes,
2482                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
2483
2484                 if (head->is_data) {
2485                         spin_lock(&delayed_refs->lock);
2486                         delayed_refs->pending_csums -= head->num_bytes;
2487                         spin_unlock(&delayed_refs->lock);
2488                 }
2489         }
2490
2491         if (head->must_insert_reserved) {
2492                 btrfs_pin_extent(fs_info, head->bytenr,
2493                                  head->num_bytes, 1);
2494                 if (head->is_data) {
2495                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2496                                               head->num_bytes);
2497                 }
2498         }
2499
2500         /* Also free its reserved qgroup space */
2501         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2502                                       head->qgroup_reserved);
2503         btrfs_delayed_ref_unlock(head);
2504         btrfs_put_delayed_ref_head(head);
2505         return 0;
2506 }
2507
2508 /*
2509  * Returns 0 on success or if called with an already aborted transaction.
2510  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2511  */
2512 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2513                                              unsigned long nr)
2514 {
2515         struct btrfs_fs_info *fs_info = trans->fs_info;
2516         struct btrfs_delayed_ref_root *delayed_refs;
2517         struct btrfs_delayed_ref_node *ref;
2518         struct btrfs_delayed_ref_head *locked_ref = NULL;
2519         struct btrfs_delayed_extent_op *extent_op;
2520         ktime_t start = ktime_get();
2521         int ret;
2522         unsigned long count = 0;
2523         unsigned long actual_count = 0;
2524         int must_insert_reserved = 0;
2525
2526         delayed_refs = &trans->transaction->delayed_refs;
2527         while (1) {
2528                 if (!locked_ref) {
2529                         if (count >= nr)
2530                                 break;
2531
2532                         spin_lock(&delayed_refs->lock);
2533                         locked_ref = btrfs_select_ref_head(trans);
2534                         if (!locked_ref) {
2535                                 spin_unlock(&delayed_refs->lock);
2536                                 break;
2537                         }
2538
2539                         /* grab the lock that says we are going to process
2540                          * all the refs for this head */
2541                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2542                         spin_unlock(&delayed_refs->lock);
2543                         /*
2544                          * we may have dropped the spin lock to get the head
2545                          * mutex lock, and that might have given someone else
2546                          * time to free the head.  If that's true, it has been
2547                          * removed from our list and we can move on.
2548                          */
2549                         if (ret == -EAGAIN) {
2550                                 locked_ref = NULL;
2551                                 count++;
2552                                 continue;
2553                         }
2554                 }
2555
2556                 /*
2557                  * We need to try and merge add/drops of the same ref since we
2558                  * can run into issues with relocate dropping the implicit ref
2559                  * and then it being added back again before the drop can
2560                  * finish.  If we merged anything we need to re-loop so we can
2561                  * get a good ref.
2562                  * Or we can get node references of the same type that weren't
2563                  * merged when created due to bumps in the tree mod seq, and
2564                  * we need to merge them to prevent adding an inline extent
2565                  * backref before dropping it (triggering a BUG_ON at
2566                  * insert_inline_extent_backref()).
2567                  */
2568                 spin_lock(&locked_ref->lock);
2569                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2570
2571                 ref = select_delayed_ref(locked_ref);
2572
2573                 if (ref && ref->seq &&
2574                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
2575                         spin_unlock(&locked_ref->lock);
2576                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2577                         locked_ref = NULL;
2578                         cond_resched();
2579                         count++;
2580                         continue;
2581                 }
2582
2583                 /*
2584                  * We're done processing refs in this ref_head, clean everything
2585                  * up and move on to the next ref_head.
2586                  */
2587                 if (!ref) {
2588                         ret = cleanup_ref_head(trans, locked_ref);
2589                         if (ret > 0 ) {
2590                                 /* We dropped our lock, we need to loop. */
2591                                 ret = 0;
2592                                 continue;
2593                         } else if (ret) {
2594                                 return ret;
2595                         }
2596                         locked_ref = NULL;
2597                         count++;
2598                         continue;
2599                 }
2600
2601                 actual_count++;
2602                 ref->in_tree = 0;
2603                 rb_erase(&ref->ref_node, &locked_ref->ref_tree);
2604                 RB_CLEAR_NODE(&ref->ref_node);
2605                 if (!list_empty(&ref->add_list))
2606                         list_del(&ref->add_list);
2607                 /*
2608                  * When we play the delayed ref, also correct the ref_mod on
2609                  * head
2610                  */
2611                 switch (ref->action) {
2612                 case BTRFS_ADD_DELAYED_REF:
2613                 case BTRFS_ADD_DELAYED_EXTENT:
2614                         locked_ref->ref_mod -= ref->ref_mod;
2615                         break;
2616                 case BTRFS_DROP_DELAYED_REF:
2617                         locked_ref->ref_mod += ref->ref_mod;
2618                         break;
2619                 default:
2620                         WARN_ON(1);
2621                 }
2622                 atomic_dec(&delayed_refs->num_entries);
2623
2624                 /*
2625                  * Record the must-insert_reserved flag before we drop the spin
2626                  * lock.
2627                  */
2628                 must_insert_reserved = locked_ref->must_insert_reserved;
2629                 locked_ref->must_insert_reserved = 0;
2630
2631                 extent_op = locked_ref->extent_op;
2632                 locked_ref->extent_op = NULL;
2633                 spin_unlock(&locked_ref->lock);
2634
2635                 ret = run_one_delayed_ref(trans, ref, extent_op,
2636                                           must_insert_reserved);
2637
2638                 btrfs_free_delayed_extent_op(extent_op);
2639                 if (ret) {
2640                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2641                         btrfs_put_delayed_ref(ref);
2642                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2643                                     ret);
2644                         return ret;
2645                 }
2646
2647                 btrfs_put_delayed_ref(ref);
2648                 count++;
2649                 cond_resched();
2650         }
2651
2652         /*
2653          * We don't want to include ref heads since we can have empty ref heads
2654          * and those will drastically skew our runtime down since we just do
2655          * accounting, no actual extent tree updates.
2656          */
2657         if (actual_count > 0) {
2658                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2659                 u64 avg;
2660
2661                 /*
2662                  * We weigh the current average higher than our current runtime
2663                  * to avoid large swings in the average.
2664                  */
2665                 spin_lock(&delayed_refs->lock);
2666                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2667                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2668                 spin_unlock(&delayed_refs->lock);
2669         }
2670         return 0;
2671 }
2672
2673 #ifdef SCRAMBLE_DELAYED_REFS
2674 /*
2675  * Normally delayed refs get processed in ascending bytenr order. This
2676  * correlates in most cases to the order added. To expose dependencies on this
2677  * order, we start to process the tree in the middle instead of the beginning
2678  */
2679 static u64 find_middle(struct rb_root *root)
2680 {
2681         struct rb_node *n = root->rb_node;
2682         struct btrfs_delayed_ref_node *entry;
2683         int alt = 1;
2684         u64 middle;
2685         u64 first = 0, last = 0;
2686
2687         n = rb_first(root);
2688         if (n) {
2689                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2690                 first = entry->bytenr;
2691         }
2692         n = rb_last(root);
2693         if (n) {
2694                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2695                 last = entry->bytenr;
2696         }
2697         n = root->rb_node;
2698
2699         while (n) {
2700                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2701                 WARN_ON(!entry->in_tree);
2702
2703                 middle = entry->bytenr;
2704
2705                 if (alt)
2706                         n = n->rb_left;
2707                 else
2708                         n = n->rb_right;
2709
2710                 alt = 1 - alt;
2711         }
2712         return middle;
2713 }
2714 #endif
2715
2716 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2717 {
2718         u64 num_bytes;
2719
2720         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2721                              sizeof(struct btrfs_extent_inline_ref));
2722         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2723                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2724
2725         /*
2726          * We don't ever fill up leaves all the way so multiply by 2 just to be
2727          * closer to what we're really going to want to use.
2728          */
2729         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2730 }
2731
2732 /*
2733  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2734  * would require to store the csums for that many bytes.
2735  */
2736 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2737 {
2738         u64 csum_size;
2739         u64 num_csums_per_leaf;
2740         u64 num_csums;
2741
2742         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2743         num_csums_per_leaf = div64_u64(csum_size,
2744                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2745         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2746         num_csums += num_csums_per_leaf - 1;
2747         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2748         return num_csums;
2749 }
2750
2751 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2752                                        struct btrfs_fs_info *fs_info)
2753 {
2754         struct btrfs_block_rsv *global_rsv;
2755         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2756         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2757         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2758         u64 num_bytes, num_dirty_bgs_bytes;
2759         int ret = 0;
2760
2761         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2762         num_heads = heads_to_leaves(fs_info, num_heads);
2763         if (num_heads > 1)
2764                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2765         num_bytes <<= 1;
2766         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2767                                                         fs_info->nodesize;
2768         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2769                                                              num_dirty_bgs);
2770         global_rsv = &fs_info->global_block_rsv;
2771
2772         /*
2773          * If we can't allocate any more chunks lets make sure we have _lots_ of
2774          * wiggle room since running delayed refs can create more delayed refs.
2775          */
2776         if (global_rsv->space_info->full) {
2777                 num_dirty_bgs_bytes <<= 1;
2778                 num_bytes <<= 1;
2779         }
2780
2781         spin_lock(&global_rsv->lock);
2782         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2783                 ret = 1;
2784         spin_unlock(&global_rsv->lock);
2785         return ret;
2786 }
2787
2788 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2789                                        struct btrfs_fs_info *fs_info)
2790 {
2791         u64 num_entries =
2792                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2793         u64 avg_runtime;
2794         u64 val;
2795
2796         smp_mb();
2797         avg_runtime = fs_info->avg_delayed_ref_runtime;
2798         val = num_entries * avg_runtime;
2799         if (val >= NSEC_PER_SEC)
2800                 return 1;
2801         if (val >= NSEC_PER_SEC / 2)
2802                 return 2;
2803
2804         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2805 }
2806
2807 struct async_delayed_refs {
2808         struct btrfs_root *root;
2809         u64 transid;
2810         int count;
2811         int error;
2812         int sync;
2813         struct completion wait;
2814         struct btrfs_work work;
2815 };
2816
2817 static inline struct async_delayed_refs *
2818 to_async_delayed_refs(struct btrfs_work *work)
2819 {
2820         return container_of(work, struct async_delayed_refs, work);
2821 }
2822
2823 static void delayed_ref_async_start(struct btrfs_work *work)
2824 {
2825         struct async_delayed_refs *async = to_async_delayed_refs(work);
2826         struct btrfs_trans_handle *trans;
2827         struct btrfs_fs_info *fs_info = async->root->fs_info;
2828         int ret;
2829
2830         /* if the commit is already started, we don't need to wait here */
2831         if (btrfs_transaction_blocked(fs_info))
2832                 goto done;
2833
2834         trans = btrfs_join_transaction(async->root);
2835         if (IS_ERR(trans)) {
2836                 async->error = PTR_ERR(trans);
2837                 goto done;
2838         }
2839
2840         /*
2841          * trans->sync means that when we call end_transaction, we won't
2842          * wait on delayed refs
2843          */
2844         trans->sync = true;
2845
2846         /* Don't bother flushing if we got into a different transaction */
2847         if (trans->transid > async->transid)
2848                 goto end;
2849
2850         ret = btrfs_run_delayed_refs(trans, async->count);
2851         if (ret)
2852                 async->error = ret;
2853 end:
2854         ret = btrfs_end_transaction(trans);
2855         if (ret && !async->error)
2856                 async->error = ret;
2857 done:
2858         if (async->sync)
2859                 complete(&async->wait);
2860         else
2861                 kfree(async);
2862 }
2863
2864 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2865                                  unsigned long count, u64 transid, int wait)
2866 {
2867         struct async_delayed_refs *async;
2868         int ret;
2869
2870         async = kmalloc(sizeof(*async), GFP_NOFS);
2871         if (!async)
2872                 return -ENOMEM;
2873
2874         async->root = fs_info->tree_root;
2875         async->count = count;
2876         async->error = 0;
2877         async->transid = transid;
2878         if (wait)
2879                 async->sync = 1;
2880         else
2881                 async->sync = 0;
2882         init_completion(&async->wait);
2883
2884         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2885                         delayed_ref_async_start, NULL, NULL);
2886
2887         btrfs_queue_work(fs_info->extent_workers, &async->work);
2888
2889         if (wait) {
2890                 wait_for_completion(&async->wait);
2891                 ret = async->error;
2892                 kfree(async);
2893                 return ret;
2894         }
2895         return 0;
2896 }
2897
2898 /*
2899  * this starts processing the delayed reference count updates and
2900  * extent insertions we have queued up so far.  count can be
2901  * 0, which means to process everything in the tree at the start
2902  * of the run (but not newly added entries), or it can be some target
2903  * number you'd like to process.
2904  *
2905  * Returns 0 on success or if called with an aborted transaction
2906  * Returns <0 on error and aborts the transaction
2907  */
2908 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2909                            unsigned long count)
2910 {
2911         struct btrfs_fs_info *fs_info = trans->fs_info;
2912         struct rb_node *node;
2913         struct btrfs_delayed_ref_root *delayed_refs;
2914         struct btrfs_delayed_ref_head *head;
2915         int ret;
2916         int run_all = count == (unsigned long)-1;
2917
2918         /* We'll clean this up in btrfs_cleanup_transaction */
2919         if (trans->aborted)
2920                 return 0;
2921
2922         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2923                 return 0;
2924
2925         delayed_refs = &trans->transaction->delayed_refs;
2926         if (count == 0)
2927                 count = atomic_read(&delayed_refs->num_entries) * 2;
2928
2929 again:
2930 #ifdef SCRAMBLE_DELAYED_REFS
2931         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2932 #endif
2933         ret = __btrfs_run_delayed_refs(trans, count);
2934         if (ret < 0) {
2935                 btrfs_abort_transaction(trans, ret);
2936                 return ret;
2937         }
2938
2939         if (run_all) {
2940                 if (!list_empty(&trans->new_bgs))
2941                         btrfs_create_pending_block_groups(trans);
2942
2943                 spin_lock(&delayed_refs->lock);
2944                 node = rb_first(&delayed_refs->href_root);
2945                 if (!node) {
2946                         spin_unlock(&delayed_refs->lock);
2947                         goto out;
2948                 }
2949                 head = rb_entry(node, struct btrfs_delayed_ref_head,
2950                                 href_node);
2951                 refcount_inc(&head->refs);
2952                 spin_unlock(&delayed_refs->lock);
2953
2954                 /* Mutex was contended, block until it's released and retry. */
2955                 mutex_lock(&head->mutex);
2956                 mutex_unlock(&head->mutex);
2957
2958                 btrfs_put_delayed_ref_head(head);
2959                 cond_resched();
2960                 goto again;
2961         }
2962 out:
2963         return 0;
2964 }
2965
2966 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2967                                 struct btrfs_fs_info *fs_info,
2968                                 u64 bytenr, u64 num_bytes, u64 flags,
2969                                 int level, int is_data)
2970 {
2971         struct btrfs_delayed_extent_op *extent_op;
2972         int ret;
2973
2974         extent_op = btrfs_alloc_delayed_extent_op();
2975         if (!extent_op)
2976                 return -ENOMEM;
2977
2978         extent_op->flags_to_set = flags;
2979         extent_op->update_flags = true;
2980         extent_op->update_key = false;
2981         extent_op->is_data = is_data ? true : false;
2982         extent_op->level = level;
2983
2984         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
2985                                           num_bytes, extent_op);
2986         if (ret)
2987                 btrfs_free_delayed_extent_op(extent_op);
2988         return ret;
2989 }
2990
2991 static noinline int check_delayed_ref(struct btrfs_root *root,
2992                                       struct btrfs_path *path,
2993                                       u64 objectid, u64 offset, u64 bytenr)
2994 {
2995         struct btrfs_delayed_ref_head *head;
2996         struct btrfs_delayed_ref_node *ref;
2997         struct btrfs_delayed_data_ref *data_ref;
2998         struct btrfs_delayed_ref_root *delayed_refs;
2999         struct btrfs_transaction *cur_trans;
3000         struct rb_node *node;
3001         int ret = 0;
3002
3003         spin_lock(&root->fs_info->trans_lock);
3004         cur_trans = root->fs_info->running_transaction;
3005         if (cur_trans)
3006                 refcount_inc(&cur_trans->use_count);
3007         spin_unlock(&root->fs_info->trans_lock);
3008         if (!cur_trans)
3009                 return 0;
3010
3011         delayed_refs = &cur_trans->delayed_refs;
3012         spin_lock(&delayed_refs->lock);
3013         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3014         if (!head) {
3015                 spin_unlock(&delayed_refs->lock);
3016                 btrfs_put_transaction(cur_trans);
3017                 return 0;
3018         }
3019
3020         if (!mutex_trylock(&head->mutex)) {
3021                 refcount_inc(&head->refs);
3022                 spin_unlock(&delayed_refs->lock);
3023
3024                 btrfs_release_path(path);
3025
3026                 /*
3027                  * Mutex was contended, block until it's released and let
3028                  * caller try again
3029                  */
3030                 mutex_lock(&head->mutex);
3031                 mutex_unlock(&head->mutex);
3032                 btrfs_put_delayed_ref_head(head);
3033                 btrfs_put_transaction(cur_trans);
3034                 return -EAGAIN;
3035         }
3036         spin_unlock(&delayed_refs->lock);
3037
3038         spin_lock(&head->lock);
3039         /*
3040          * XXX: We should replace this with a proper search function in the
3041          * future.
3042          */
3043         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
3044                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3045                 /* If it's a shared ref we know a cross reference exists */
3046                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3047                         ret = 1;
3048                         break;
3049                 }
3050
3051                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3052
3053                 /*
3054                  * If our ref doesn't match the one we're currently looking at
3055                  * then we have a cross reference.
3056                  */
3057                 if (data_ref->root != root->root_key.objectid ||
3058                     data_ref->objectid != objectid ||
3059                     data_ref->offset != offset) {
3060                         ret = 1;
3061                         break;
3062                 }
3063         }
3064         spin_unlock(&head->lock);
3065         mutex_unlock(&head->mutex);
3066         btrfs_put_transaction(cur_trans);
3067         return ret;
3068 }
3069
3070 static noinline int check_committed_ref(struct btrfs_root *root,
3071                                         struct btrfs_path *path,
3072                                         u64 objectid, u64 offset, u64 bytenr)
3073 {
3074         struct btrfs_fs_info *fs_info = root->fs_info;
3075         struct btrfs_root *extent_root = fs_info->extent_root;
3076         struct extent_buffer *leaf;
3077         struct btrfs_extent_data_ref *ref;
3078         struct btrfs_extent_inline_ref *iref;
3079         struct btrfs_extent_item *ei;
3080         struct btrfs_key key;
3081         u32 item_size;
3082         int type;
3083         int ret;
3084
3085         key.objectid = bytenr;
3086         key.offset = (u64)-1;
3087         key.type = BTRFS_EXTENT_ITEM_KEY;
3088
3089         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3090         if (ret < 0)
3091                 goto out;
3092         BUG_ON(ret == 0); /* Corruption */
3093
3094         ret = -ENOENT;
3095         if (path->slots[0] == 0)
3096                 goto out;
3097
3098         path->slots[0]--;
3099         leaf = path->nodes[0];
3100         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3101
3102         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3103                 goto out;
3104
3105         ret = 1;
3106         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3107         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3108
3109         if (item_size != sizeof(*ei) +
3110             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3111                 goto out;
3112
3113         if (btrfs_extent_generation(leaf, ei) <=
3114             btrfs_root_last_snapshot(&root->root_item))
3115                 goto out;
3116
3117         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3118
3119         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3120         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3121                 goto out;
3122
3123         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3124         if (btrfs_extent_refs(leaf, ei) !=
3125             btrfs_extent_data_ref_count(leaf, ref) ||
3126             btrfs_extent_data_ref_root(leaf, ref) !=
3127             root->root_key.objectid ||
3128             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3129             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3130                 goto out;
3131
3132         ret = 0;
3133 out:
3134         return ret;
3135 }
3136
3137 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3138                           u64 bytenr)
3139 {
3140         struct btrfs_path *path;
3141         int ret;
3142         int ret2;
3143
3144         path = btrfs_alloc_path();
3145         if (!path)
3146                 return -ENOMEM;
3147
3148         do {
3149                 ret = check_committed_ref(root, path, objectid,
3150                                           offset, bytenr);
3151                 if (ret && ret != -ENOENT)
3152                         goto out;
3153
3154                 ret2 = check_delayed_ref(root, path, objectid,
3155                                          offset, bytenr);
3156         } while (ret2 == -EAGAIN);
3157
3158         if (ret2 && ret2 != -ENOENT) {
3159                 ret = ret2;
3160                 goto out;
3161         }
3162
3163         if (ret != -ENOENT || ret2 != -ENOENT)
3164                 ret = 0;
3165 out:
3166         btrfs_free_path(path);
3167         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3168                 WARN_ON(ret > 0);
3169         return ret;
3170 }
3171
3172 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3173                            struct btrfs_root *root,
3174                            struct extent_buffer *buf,
3175                            int full_backref, int inc)
3176 {
3177         struct btrfs_fs_info *fs_info = root->fs_info;
3178         u64 bytenr;
3179         u64 num_bytes;
3180         u64 parent;
3181         u64 ref_root;
3182         u32 nritems;
3183         struct btrfs_key key;
3184         struct btrfs_file_extent_item *fi;
3185         int i;
3186         int level;
3187         int ret = 0;
3188         int (*process_func)(struct btrfs_trans_handle *,
3189                             struct btrfs_root *,
3190                             u64, u64, u64, u64, u64, u64);
3191
3192
3193         if (btrfs_is_testing(fs_info))
3194                 return 0;
3195
3196         ref_root = btrfs_header_owner(buf);
3197         nritems = btrfs_header_nritems(buf);
3198         level = btrfs_header_level(buf);
3199
3200         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3201                 return 0;
3202
3203         if (inc)
3204                 process_func = btrfs_inc_extent_ref;
3205         else
3206                 process_func = btrfs_free_extent;
3207
3208         if (full_backref)
3209                 parent = buf->start;
3210         else
3211                 parent = 0;
3212
3213         for (i = 0; i < nritems; i++) {
3214                 if (level == 0) {
3215                         btrfs_item_key_to_cpu(buf, &key, i);
3216                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3217                                 continue;
3218                         fi = btrfs_item_ptr(buf, i,
3219                                             struct btrfs_file_extent_item);
3220                         if (btrfs_file_extent_type(buf, fi) ==
3221                             BTRFS_FILE_EXTENT_INLINE)
3222                                 continue;
3223                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3224                         if (bytenr == 0)
3225                                 continue;
3226
3227                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3228                         key.offset -= btrfs_file_extent_offset(buf, fi);
3229                         ret = process_func(trans, root, bytenr, num_bytes,
3230                                            parent, ref_root, key.objectid,
3231                                            key.offset);
3232                         if (ret)
3233                                 goto fail;
3234                 } else {
3235                         bytenr = btrfs_node_blockptr(buf, i);
3236                         num_bytes = fs_info->nodesize;
3237                         ret = process_func(trans, root, bytenr, num_bytes,
3238                                            parent, ref_root, level - 1, 0);
3239                         if (ret)
3240                                 goto fail;
3241                 }
3242         }
3243         return 0;
3244 fail:
3245         return ret;
3246 }
3247
3248 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3249                   struct extent_buffer *buf, int full_backref)
3250 {
3251         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3252 }
3253
3254 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3255                   struct extent_buffer *buf, int full_backref)
3256 {
3257         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3258 }
3259
3260 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3261                                  struct btrfs_fs_info *fs_info,
3262                                  struct btrfs_path *path,
3263                                  struct btrfs_block_group_cache *cache)
3264 {
3265         int ret;
3266         struct btrfs_root *extent_root = fs_info->extent_root;
3267         unsigned long bi;
3268         struct extent_buffer *leaf;
3269
3270         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3271         if (ret) {
3272                 if (ret > 0)
3273                         ret = -ENOENT;
3274                 goto fail;
3275         }
3276
3277         leaf = path->nodes[0];
3278         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3279         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3280         btrfs_mark_buffer_dirty(leaf);
3281 fail:
3282         btrfs_release_path(path);
3283         return ret;
3284
3285 }
3286
3287 static struct btrfs_block_group_cache *
3288 next_block_group(struct btrfs_fs_info *fs_info,
3289                  struct btrfs_block_group_cache *cache)
3290 {
3291         struct rb_node *node;
3292
3293         spin_lock(&fs_info->block_group_cache_lock);
3294
3295         /* If our block group was removed, we need a full search. */
3296         if (RB_EMPTY_NODE(&cache->cache_node)) {
3297                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3298
3299                 spin_unlock(&fs_info->block_group_cache_lock);
3300                 btrfs_put_block_group(cache);
3301                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3302         }
3303         node = rb_next(&cache->cache_node);
3304         btrfs_put_block_group(cache);
3305         if (node) {
3306                 cache = rb_entry(node, struct btrfs_block_group_cache,
3307                                  cache_node);
3308                 btrfs_get_block_group(cache);
3309         } else
3310                 cache = NULL;
3311         spin_unlock(&fs_info->block_group_cache_lock);
3312         return cache;
3313 }
3314
3315 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3316                             struct btrfs_trans_handle *trans,
3317                             struct btrfs_path *path)
3318 {
3319         struct btrfs_fs_info *fs_info = block_group->fs_info;
3320         struct btrfs_root *root = fs_info->tree_root;
3321         struct inode *inode = NULL;
3322         struct extent_changeset *data_reserved = NULL;
3323         u64 alloc_hint = 0;
3324         int dcs = BTRFS_DC_ERROR;
3325         u64 num_pages = 0;
3326         int retries = 0;
3327         int ret = 0;
3328
3329         /*
3330          * If this block group is smaller than 100 megs don't bother caching the
3331          * block group.
3332          */
3333         if (block_group->key.offset < (100 * SZ_1M)) {
3334                 spin_lock(&block_group->lock);
3335                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3336                 spin_unlock(&block_group->lock);
3337                 return 0;
3338         }
3339
3340         if (trans->aborted)
3341                 return 0;
3342 again:
3343         inode = lookup_free_space_inode(fs_info, block_group, path);
3344         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3345                 ret = PTR_ERR(inode);
3346                 btrfs_release_path(path);
3347                 goto out;
3348         }
3349
3350         if (IS_ERR(inode)) {
3351                 BUG_ON(retries);
3352                 retries++;
3353
3354                 if (block_group->ro)
3355                         goto out_free;
3356
3357                 ret = create_free_space_inode(fs_info, trans, block_group,
3358                                               path);
3359                 if (ret)
3360                         goto out_free;
3361                 goto again;
3362         }
3363
3364         /*
3365          * We want to set the generation to 0, that way if anything goes wrong
3366          * from here on out we know not to trust this cache when we load up next
3367          * time.
3368          */
3369         BTRFS_I(inode)->generation = 0;
3370         ret = btrfs_update_inode(trans, root, inode);
3371         if (ret) {
3372                 /*
3373                  * So theoretically we could recover from this, simply set the
3374                  * super cache generation to 0 so we know to invalidate the
3375                  * cache, but then we'd have to keep track of the block groups
3376                  * that fail this way so we know we _have_ to reset this cache
3377                  * before the next commit or risk reading stale cache.  So to
3378                  * limit our exposure to horrible edge cases lets just abort the
3379                  * transaction, this only happens in really bad situations
3380                  * anyway.
3381                  */
3382                 btrfs_abort_transaction(trans, ret);
3383                 goto out_put;
3384         }
3385         WARN_ON(ret);
3386
3387         /* We've already setup this transaction, go ahead and exit */
3388         if (block_group->cache_generation == trans->transid &&
3389             i_size_read(inode)) {
3390                 dcs = BTRFS_DC_SETUP;
3391                 goto out_put;
3392         }
3393
3394         if (i_size_read(inode) > 0) {
3395                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3396                                         &fs_info->global_block_rsv);
3397                 if (ret)
3398                         goto out_put;
3399
3400                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3401                 if (ret)
3402                         goto out_put;
3403         }
3404
3405         spin_lock(&block_group->lock);
3406         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3407             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3408                 /*
3409                  * don't bother trying to write stuff out _if_
3410                  * a) we're not cached,
3411                  * b) we're with nospace_cache mount option,
3412                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3413                  */
3414                 dcs = BTRFS_DC_WRITTEN;
3415                 spin_unlock(&block_group->lock);
3416                 goto out_put;
3417         }
3418         spin_unlock(&block_group->lock);
3419
3420         /*
3421          * We hit an ENOSPC when setting up the cache in this transaction, just
3422          * skip doing the setup, we've already cleared the cache so we're safe.
3423          */
3424         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3425                 ret = -ENOSPC;
3426                 goto out_put;
3427         }
3428
3429         /*
3430          * Try to preallocate enough space based on how big the block group is.
3431          * Keep in mind this has to include any pinned space which could end up
3432          * taking up quite a bit since it's not folded into the other space
3433          * cache.
3434          */
3435         num_pages = div_u64(block_group->key.offset, SZ_256M);
3436         if (!num_pages)
3437                 num_pages = 1;
3438
3439         num_pages *= 16;
3440         num_pages *= PAGE_SIZE;
3441
3442         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3443         if (ret)
3444                 goto out_put;
3445
3446         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3447                                               num_pages, num_pages,
3448                                               &alloc_hint);
3449         /*
3450          * Our cache requires contiguous chunks so that we don't modify a bunch
3451          * of metadata or split extents when writing the cache out, which means
3452          * we can enospc if we are heavily fragmented in addition to just normal
3453          * out of space conditions.  So if we hit this just skip setting up any
3454          * other block groups for this transaction, maybe we'll unpin enough
3455          * space the next time around.
3456          */
3457         if (!ret)
3458                 dcs = BTRFS_DC_SETUP;
3459         else if (ret == -ENOSPC)
3460                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3461
3462 out_put:
3463         iput(inode);
3464 out_free:
3465         btrfs_release_path(path);
3466 out:
3467         spin_lock(&block_group->lock);
3468         if (!ret && dcs == BTRFS_DC_SETUP)
3469                 block_group->cache_generation = trans->transid;
3470         block_group->disk_cache_state = dcs;
3471         spin_unlock(&block_group->lock);
3472
3473         extent_changeset_free(data_reserved);
3474         return ret;
3475 }
3476
3477 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3478                             struct btrfs_fs_info *fs_info)
3479 {
3480         struct btrfs_block_group_cache *cache, *tmp;
3481         struct btrfs_transaction *cur_trans = trans->transaction;
3482         struct btrfs_path *path;
3483
3484         if (list_empty(&cur_trans->dirty_bgs) ||
3485             !btrfs_test_opt(fs_info, SPACE_CACHE))
3486                 return 0;
3487
3488         path = btrfs_alloc_path();
3489         if (!path)
3490                 return -ENOMEM;
3491
3492         /* Could add new block groups, use _safe just in case */
3493         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3494                                  dirty_list) {
3495                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3496                         cache_save_setup(cache, trans, path);
3497         }
3498
3499         btrfs_free_path(path);
3500         return 0;
3501 }
3502
3503 /*
3504  * transaction commit does final block group cache writeback during a
3505  * critical section where nothing is allowed to change the FS.  This is
3506  * required in order for the cache to actually match the block group,
3507  * but can introduce a lot of latency into the commit.
3508  *
3509  * So, btrfs_start_dirty_block_groups is here to kick off block group
3510  * cache IO.  There's a chance we'll have to redo some of it if the
3511  * block group changes again during the commit, but it greatly reduces
3512  * the commit latency by getting rid of the easy block groups while
3513  * we're still allowing others to join the commit.
3514  */
3515 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3516 {
3517         struct btrfs_fs_info *fs_info = trans->fs_info;
3518         struct btrfs_block_group_cache *cache;
3519         struct btrfs_transaction *cur_trans = trans->transaction;
3520         int ret = 0;
3521         int should_put;
3522         struct btrfs_path *path = NULL;
3523         LIST_HEAD(dirty);
3524         struct list_head *io = &cur_trans->io_bgs;
3525         int num_started = 0;
3526         int loops = 0;
3527
3528         spin_lock(&cur_trans->dirty_bgs_lock);
3529         if (list_empty(&cur_trans->dirty_bgs)) {
3530                 spin_unlock(&cur_trans->dirty_bgs_lock);
3531                 return 0;
3532         }
3533         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3534         spin_unlock(&cur_trans->dirty_bgs_lock);
3535
3536 again:
3537         /*
3538          * make sure all the block groups on our dirty list actually
3539          * exist
3540          */
3541         btrfs_create_pending_block_groups(trans);
3542
3543         if (!path) {
3544                 path = btrfs_alloc_path();
3545                 if (!path)
3546                         return -ENOMEM;
3547         }
3548
3549         /*
3550          * cache_write_mutex is here only to save us from balance or automatic
3551          * removal of empty block groups deleting this block group while we are
3552          * writing out the cache
3553          */
3554         mutex_lock(&trans->transaction->cache_write_mutex);
3555         while (!list_empty(&dirty)) {
3556                 cache = list_first_entry(&dirty,
3557                                          struct btrfs_block_group_cache,
3558                                          dirty_list);
3559                 /*
3560                  * this can happen if something re-dirties a block
3561                  * group that is already under IO.  Just wait for it to
3562                  * finish and then do it all again
3563                  */
3564                 if (!list_empty(&cache->io_list)) {
3565                         list_del_init(&cache->io_list);
3566                         btrfs_wait_cache_io(trans, cache, path);
3567                         btrfs_put_block_group(cache);
3568                 }
3569
3570
3571                 /*
3572                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3573                  * if it should update the cache_state.  Don't delete
3574                  * until after we wait.
3575                  *
3576                  * Since we're not running in the commit critical section
3577                  * we need the dirty_bgs_lock to protect from update_block_group
3578                  */
3579                 spin_lock(&cur_trans->dirty_bgs_lock);
3580                 list_del_init(&cache->dirty_list);
3581                 spin_unlock(&cur_trans->dirty_bgs_lock);
3582
3583                 should_put = 1;
3584
3585                 cache_save_setup(cache, trans, path);
3586
3587                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3588                         cache->io_ctl.inode = NULL;
3589                         ret = btrfs_write_out_cache(fs_info, trans,
3590                                                     cache, path);
3591                         if (ret == 0 && cache->io_ctl.inode) {
3592                                 num_started++;
3593                                 should_put = 0;
3594
3595                                 /*
3596                                  * The cache_write_mutex is protecting the
3597                                  * io_list, also refer to the definition of
3598                                  * btrfs_transaction::io_bgs for more details
3599                                  */
3600                                 list_add_tail(&cache->io_list, io);
3601                         } else {
3602                                 /*
3603                                  * if we failed to write the cache, the
3604                                  * generation will be bad and life goes on
3605                                  */
3606                                 ret = 0;
3607                         }
3608                 }
3609                 if (!ret) {
3610                         ret = write_one_cache_group(trans, fs_info,
3611                                                     path, cache);
3612                         /*
3613                          * Our block group might still be attached to the list
3614                          * of new block groups in the transaction handle of some
3615                          * other task (struct btrfs_trans_handle->new_bgs). This
3616                          * means its block group item isn't yet in the extent
3617                          * tree. If this happens ignore the error, as we will
3618                          * try again later in the critical section of the
3619                          * transaction commit.
3620                          */
3621                         if (ret == -ENOENT) {
3622                                 ret = 0;
3623                                 spin_lock(&cur_trans->dirty_bgs_lock);
3624                                 if (list_empty(&cache->dirty_list)) {
3625                                         list_add_tail(&cache->dirty_list,
3626                                                       &cur_trans->dirty_bgs);
3627                                         btrfs_get_block_group(cache);
3628                                 }
3629                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3630                         } else if (ret) {
3631                                 btrfs_abort_transaction(trans, ret);
3632                         }
3633                 }
3634
3635                 /* if its not on the io list, we need to put the block group */
3636                 if (should_put)
3637                         btrfs_put_block_group(cache);
3638
3639                 if (ret)
3640                         break;
3641
3642                 /*
3643                  * Avoid blocking other tasks for too long. It might even save
3644                  * us from writing caches for block groups that are going to be
3645                  * removed.
3646                  */
3647                 mutex_unlock(&trans->transaction->cache_write_mutex);
3648                 mutex_lock(&trans->transaction->cache_write_mutex);
3649         }
3650         mutex_unlock(&trans->transaction->cache_write_mutex);
3651
3652         /*
3653          * go through delayed refs for all the stuff we've just kicked off
3654          * and then loop back (just once)
3655          */
3656         ret = btrfs_run_delayed_refs(trans, 0);
3657         if (!ret && loops == 0) {
3658                 loops++;
3659                 spin_lock(&cur_trans->dirty_bgs_lock);
3660                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3661                 /*
3662                  * dirty_bgs_lock protects us from concurrent block group
3663                  * deletes too (not just cache_write_mutex).
3664                  */
3665                 if (!list_empty(&dirty)) {
3666                         spin_unlock(&cur_trans->dirty_bgs_lock);
3667                         goto again;
3668                 }
3669                 spin_unlock(&cur_trans->dirty_bgs_lock);
3670         } else if (ret < 0) {
3671                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3672         }
3673
3674         btrfs_free_path(path);
3675         return ret;
3676 }
3677
3678 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3679                                    struct btrfs_fs_info *fs_info)
3680 {
3681         struct btrfs_block_group_cache *cache;
3682         struct btrfs_transaction *cur_trans = trans->transaction;
3683         int ret = 0;
3684         int should_put;
3685         struct btrfs_path *path;
3686         struct list_head *io = &cur_trans->io_bgs;
3687         int num_started = 0;
3688
3689         path = btrfs_alloc_path();
3690         if (!path)
3691                 return -ENOMEM;
3692
3693         /*
3694          * Even though we are in the critical section of the transaction commit,
3695          * we can still have concurrent tasks adding elements to this
3696          * transaction's list of dirty block groups. These tasks correspond to
3697          * endio free space workers started when writeback finishes for a
3698          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3699          * allocate new block groups as a result of COWing nodes of the root
3700          * tree when updating the free space inode. The writeback for the space
3701          * caches is triggered by an earlier call to
3702          * btrfs_start_dirty_block_groups() and iterations of the following
3703          * loop.
3704          * Also we want to do the cache_save_setup first and then run the
3705          * delayed refs to make sure we have the best chance at doing this all
3706          * in one shot.
3707          */
3708         spin_lock(&cur_trans->dirty_bgs_lock);
3709         while (!list_empty(&cur_trans->dirty_bgs)) {
3710                 cache = list_first_entry(&cur_trans->dirty_bgs,
3711                                          struct btrfs_block_group_cache,
3712                                          dirty_list);
3713
3714                 /*
3715                  * this can happen if cache_save_setup re-dirties a block
3716                  * group that is already under IO.  Just wait for it to
3717                  * finish and then do it all again
3718                  */
3719                 if (!list_empty(&cache->io_list)) {
3720                         spin_unlock(&cur_trans->dirty_bgs_lock);
3721                         list_del_init(&cache->io_list);
3722                         btrfs_wait_cache_io(trans, cache, path);
3723                         btrfs_put_block_group(cache);
3724                         spin_lock(&cur_trans->dirty_bgs_lock);
3725                 }
3726
3727                 /*
3728                  * don't remove from the dirty list until after we've waited
3729                  * on any pending IO
3730                  */
3731                 list_del_init(&cache->dirty_list);
3732                 spin_unlock(&cur_trans->dirty_bgs_lock);
3733                 should_put = 1;
3734
3735                 cache_save_setup(cache, trans, path);
3736
3737                 if (!ret)
3738                         ret = btrfs_run_delayed_refs(trans,
3739                                                      (unsigned long) -1);
3740
3741                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3742                         cache->io_ctl.inode = NULL;
3743                         ret = btrfs_write_out_cache(fs_info, trans,
3744                                                     cache, path);
3745                         if (ret == 0 && cache->io_ctl.inode) {
3746                                 num_started++;
3747                                 should_put = 0;
3748                                 list_add_tail(&cache->io_list, io);
3749                         } else {
3750                                 /*
3751                                  * if we failed to write the cache, the
3752                                  * generation will be bad and life goes on
3753                                  */
3754                                 ret = 0;
3755                         }
3756                 }
3757                 if (!ret) {
3758                         ret = write_one_cache_group(trans, fs_info,
3759                                                     path, cache);
3760                         /*
3761                          * One of the free space endio workers might have
3762                          * created a new block group while updating a free space
3763                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3764                          * and hasn't released its transaction handle yet, in
3765                          * which case the new block group is still attached to
3766                          * its transaction handle and its creation has not
3767                          * finished yet (no block group item in the extent tree
3768                          * yet, etc). If this is the case, wait for all free
3769                          * space endio workers to finish and retry. This is a
3770                          * a very rare case so no need for a more efficient and
3771                          * complex approach.
3772                          */
3773                         if (ret == -ENOENT) {
3774                                 wait_event(cur_trans->writer_wait,
3775                                    atomic_read(&cur_trans->num_writers) == 1);
3776                                 ret = write_one_cache_group(trans, fs_info,
3777                                                             path, cache);
3778                         }
3779                         if (ret)
3780                                 btrfs_abort_transaction(trans, ret);
3781                 }
3782
3783                 /* if its not on the io list, we need to put the block group */
3784                 if (should_put)
3785                         btrfs_put_block_group(cache);
3786                 spin_lock(&cur_trans->dirty_bgs_lock);
3787         }
3788         spin_unlock(&cur_trans->dirty_bgs_lock);
3789
3790         /*
3791          * Refer to the definition of io_bgs member for details why it's safe
3792          * to use it without any locking
3793          */
3794         while (!list_empty(io)) {
3795                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3796                                          io_list);
3797                 list_del_init(&cache->io_list);
3798                 btrfs_wait_cache_io(trans, cache, path);
3799                 btrfs_put_block_group(cache);
3800         }
3801
3802         btrfs_free_path(path);
3803         return ret;
3804 }
3805
3806 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3807 {
3808         struct btrfs_block_group_cache *block_group;
3809         int readonly = 0;
3810
3811         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3812         if (!block_group || block_group->ro)
3813                 readonly = 1;
3814         if (block_group)
3815                 btrfs_put_block_group(block_group);
3816         return readonly;
3817 }
3818
3819 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3820 {
3821         struct btrfs_block_group_cache *bg;
3822         bool ret = true;
3823
3824         bg = btrfs_lookup_block_group(fs_info, bytenr);
3825         if (!bg)
3826                 return false;
3827
3828         spin_lock(&bg->lock);
3829         if (bg->ro)
3830                 ret = false;
3831         else
3832                 atomic_inc(&bg->nocow_writers);
3833         spin_unlock(&bg->lock);
3834
3835         /* no put on block group, done by btrfs_dec_nocow_writers */
3836         if (!ret)
3837                 btrfs_put_block_group(bg);
3838
3839         return ret;
3840
3841 }
3842
3843 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3844 {
3845         struct btrfs_block_group_cache *bg;
3846
3847         bg = btrfs_lookup_block_group(fs_info, bytenr);
3848         ASSERT(bg);
3849         if (atomic_dec_and_test(&bg->nocow_writers))
3850                 wake_up_var(&bg->nocow_writers);
3851         /*
3852          * Once for our lookup and once for the lookup done by a previous call
3853          * to btrfs_inc_nocow_writers()
3854          */
3855         btrfs_put_block_group(bg);
3856         btrfs_put_block_group(bg);
3857 }
3858
3859 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3860 {
3861         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
3862 }
3863
3864 static const char *alloc_name(u64 flags)
3865 {
3866         switch (flags) {
3867         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3868                 return "mixed";
3869         case BTRFS_BLOCK_GROUP_METADATA:
3870                 return "metadata";
3871         case BTRFS_BLOCK_GROUP_DATA:
3872                 return "data";
3873         case BTRFS_BLOCK_GROUP_SYSTEM:
3874                 return "system";
3875         default:
3876                 WARN_ON(1);
3877                 return "invalid-combination";
3878         };
3879 }
3880
3881 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
3882 {
3883
3884         struct btrfs_space_info *space_info;
3885         int i;
3886         int ret;
3887
3888         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
3889         if (!space_info)
3890                 return -ENOMEM;
3891
3892         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
3893                                  GFP_KERNEL);
3894         if (ret) {
3895                 kfree(space_info);
3896                 return ret;
3897         }
3898
3899         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3900                 INIT_LIST_HEAD(&space_info->block_groups[i]);
3901         init_rwsem(&space_info->groups_sem);
3902         spin_lock_init(&space_info->lock);
3903         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3904         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3905         init_waitqueue_head(&space_info->wait);
3906         INIT_LIST_HEAD(&space_info->ro_bgs);
3907         INIT_LIST_HEAD(&space_info->tickets);
3908         INIT_LIST_HEAD(&space_info->priority_tickets);
3909
3910         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
3911                                     info->space_info_kobj, "%s",
3912                                     alloc_name(space_info->flags));
3913         if (ret) {
3914                 percpu_counter_destroy(&space_info->total_bytes_pinned);
3915                 kfree(space_info);
3916                 return ret;
3917         }
3918
3919         list_add_rcu(&space_info->list, &info->space_info);
3920         if (flags & BTRFS_BLOCK_GROUP_DATA)
3921                 info->data_sinfo = space_info;
3922
3923         return ret;
3924 }
3925
3926 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
3927                              u64 total_bytes, u64 bytes_used,
3928                              u64 bytes_readonly,
3929                              struct btrfs_space_info **space_info)
3930 {
3931         struct btrfs_space_info *found;
3932         int factor;
3933
3934         factor = btrfs_bg_type_to_factor(flags);
3935
3936         found = __find_space_info(info, flags);
3937         ASSERT(found);
3938         spin_lock(&found->lock);
3939         found->total_bytes += total_bytes;
3940         found->disk_total += total_bytes * factor;
3941         found->bytes_used += bytes_used;
3942         found->disk_used += bytes_used * factor;
3943         found->bytes_readonly += bytes_readonly;
3944         if (total_bytes > 0)
3945                 found->full = 0;
3946         space_info_add_new_bytes(info, found, total_bytes -
3947                                  bytes_used - bytes_readonly);
3948         spin_unlock(&found->lock);
3949         *space_info = found;
3950 }
3951
3952 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3953 {
3954         u64 extra_flags = chunk_to_extended(flags) &
3955                                 BTRFS_EXTENDED_PROFILE_MASK;
3956
3957         write_seqlock(&fs_info->profiles_lock);
3958         if (flags & BTRFS_BLOCK_GROUP_DATA)
3959                 fs_info->avail_data_alloc_bits |= extra_flags;
3960         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3961                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3962         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3963                 fs_info->avail_system_alloc_bits |= extra_flags;
3964         write_sequnlock(&fs_info->profiles_lock);
3965 }
3966
3967 /*
3968  * returns target flags in extended format or 0 if restripe for this
3969  * chunk_type is not in progress
3970  *
3971  * should be called with balance_lock held
3972  */
3973 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3974 {
3975         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3976         u64 target = 0;
3977
3978         if (!bctl)
3979                 return 0;
3980
3981         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3982             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3983                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3984         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3985                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3986                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3987         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3988                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3989                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3990         }
3991
3992         return target;
3993 }
3994
3995 /*
3996  * @flags: available profiles in extended format (see ctree.h)
3997  *
3998  * Returns reduced profile in chunk format.  If profile changing is in
3999  * progress (either running or paused) picks the target profile (if it's
4000  * already available), otherwise falls back to plain reducing.
4001  */
4002 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4003 {
4004         u64 num_devices = fs_info->fs_devices->rw_devices;
4005         u64 target;
4006         u64 raid_type;
4007         u64 allowed = 0;
4008
4009         /*
4010          * see if restripe for this chunk_type is in progress, if so
4011          * try to reduce to the target profile
4012          */
4013         spin_lock(&fs_info->balance_lock);
4014         target = get_restripe_target(fs_info, flags);
4015         if (target) {
4016                 /* pick target profile only if it's already available */
4017                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4018                         spin_unlock(&fs_info->balance_lock);
4019                         return extended_to_chunk(target);
4020                 }
4021         }
4022         spin_unlock(&fs_info->balance_lock);
4023
4024         /* First, mask out the RAID levels which aren't possible */
4025         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4026                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4027                         allowed |= btrfs_raid_array[raid_type].bg_flag;
4028         }
4029         allowed &= flags;
4030
4031         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4032                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4033         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4034                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4035         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4036                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4037         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4038                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4039         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4040                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4041
4042         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4043
4044         return extended_to_chunk(flags | allowed);
4045 }
4046
4047 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4048 {
4049         unsigned seq;
4050         u64 flags;
4051
4052         do {
4053                 flags = orig_flags;
4054                 seq = read_seqbegin(&fs_info->profiles_lock);
4055
4056                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4057                         flags |= fs_info->avail_data_alloc_bits;
4058                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4059                         flags |= fs_info->avail_system_alloc_bits;
4060                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4061                         flags |= fs_info->avail_metadata_alloc_bits;
4062         } while (read_seqretry(&fs_info->profiles_lock, seq));
4063
4064         return btrfs_reduce_alloc_profile(fs_info, flags);
4065 }
4066
4067 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4068 {
4069         struct btrfs_fs_info *fs_info = root->fs_info;
4070         u64 flags;
4071         u64 ret;
4072
4073         if (data)
4074                 flags = BTRFS_BLOCK_GROUP_DATA;
4075         else if (root == fs_info->chunk_root)
4076                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4077         else
4078                 flags = BTRFS_BLOCK_GROUP_METADATA;
4079
4080         ret = get_alloc_profile(fs_info, flags);
4081         return ret;
4082 }
4083
4084 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4085 {
4086         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4087 }
4088
4089 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4090 {
4091         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4092 }
4093
4094 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4095 {
4096         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4097 }
4098
4099 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4100                                  bool may_use_included)
4101 {
4102         ASSERT(s_info);
4103         return s_info->bytes_used + s_info->bytes_reserved +
4104                 s_info->bytes_pinned + s_info->bytes_readonly +
4105                 (may_use_included ? s_info->bytes_may_use : 0);
4106 }
4107
4108 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4109 {
4110         struct btrfs_root *root = inode->root;
4111         struct btrfs_fs_info *fs_info = root->fs_info;
4112         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4113         u64 used;
4114         int ret = 0;
4115         int need_commit = 2;
4116         int have_pinned_space;
4117
4118         /* make sure bytes are sectorsize aligned */
4119         bytes = ALIGN(bytes, fs_info->sectorsize);
4120
4121         if (btrfs_is_free_space_inode(inode)) {
4122                 need_commit = 0;
4123                 ASSERT(current->journal_info);
4124         }
4125
4126 again:
4127         /* make sure we have enough space to handle the data first */
4128         spin_lock(&data_sinfo->lock);
4129         used = btrfs_space_info_used(data_sinfo, true);
4130
4131         if (used + bytes > data_sinfo->total_bytes) {
4132                 struct btrfs_trans_handle *trans;
4133
4134                 /*
4135                  * if we don't have enough free bytes in this space then we need
4136                  * to alloc a new chunk.
4137                  */
4138                 if (!data_sinfo->full) {
4139                         u64 alloc_target;
4140
4141                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4142                         spin_unlock(&data_sinfo->lock);
4143
4144                         alloc_target = btrfs_data_alloc_profile(fs_info);
4145                         /*
4146                          * It is ugly that we don't call nolock join
4147                          * transaction for the free space inode case here.
4148                          * But it is safe because we only do the data space
4149                          * reservation for the free space cache in the
4150                          * transaction context, the common join transaction
4151                          * just increase the counter of the current transaction
4152                          * handler, doesn't try to acquire the trans_lock of
4153                          * the fs.
4154                          */
4155                         trans = btrfs_join_transaction(root);
4156                         if (IS_ERR(trans))
4157                                 return PTR_ERR(trans);
4158
4159                         ret = do_chunk_alloc(trans, alloc_target,
4160                                              CHUNK_ALLOC_NO_FORCE);
4161                         btrfs_end_transaction(trans);
4162                         if (ret < 0) {
4163                                 if (ret != -ENOSPC)
4164                                         return ret;
4165                                 else {
4166                                         have_pinned_space = 1;
4167                                         goto commit_trans;
4168                                 }
4169                         }
4170
4171                         goto again;
4172                 }
4173
4174                 /*
4175                  * If we don't have enough pinned space to deal with this
4176                  * allocation, and no removed chunk in current transaction,
4177                  * don't bother committing the transaction.
4178                  */
4179                 have_pinned_space = __percpu_counter_compare(
4180                         &data_sinfo->total_bytes_pinned,
4181                         used + bytes - data_sinfo->total_bytes,
4182                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
4183                 spin_unlock(&data_sinfo->lock);
4184
4185                 /* commit the current transaction and try again */
4186 commit_trans:
4187                 if (need_commit) {
4188                         need_commit--;
4189
4190                         if (need_commit > 0) {
4191                                 btrfs_start_delalloc_roots(fs_info, -1);
4192                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4193                                                          (u64)-1);
4194                         }
4195
4196                         trans = btrfs_join_transaction(root);
4197                         if (IS_ERR(trans))
4198                                 return PTR_ERR(trans);
4199                         if (have_pinned_space >= 0 ||
4200                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4201                                      &trans->transaction->flags) ||
4202                             need_commit > 0) {
4203                                 ret = btrfs_commit_transaction(trans);
4204                                 if (ret)
4205                                         return ret;
4206                                 /*
4207                                  * The cleaner kthread might still be doing iput
4208                                  * operations. Wait for it to finish so that
4209                                  * more space is released.
4210                                  */
4211                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4212                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4213                                 goto again;
4214                         } else {
4215                                 btrfs_end_transaction(trans);
4216                         }
4217                 }
4218
4219                 trace_btrfs_space_reservation(fs_info,
4220                                               "space_info:enospc",
4221                                               data_sinfo->flags, bytes, 1);
4222                 return -ENOSPC;
4223         }
4224         data_sinfo->bytes_may_use += bytes;
4225         trace_btrfs_space_reservation(fs_info, "space_info",
4226                                       data_sinfo->flags, bytes, 1);
4227         spin_unlock(&data_sinfo->lock);
4228
4229         return 0;
4230 }
4231
4232 int btrfs_check_data_free_space(struct inode *inode,
4233                         struct extent_changeset **reserved, u64 start, u64 len)
4234 {
4235         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4236         int ret;
4237
4238         /* align the range */
4239         len = round_up(start + len, fs_info->sectorsize) -
4240               round_down(start, fs_info->sectorsize);
4241         start = round_down(start, fs_info->sectorsize);
4242
4243         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4244         if (ret < 0)
4245                 return ret;
4246
4247         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4248         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4249         if (ret < 0)
4250                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4251         else
4252                 ret = 0;
4253         return ret;
4254 }
4255
4256 /*
4257  * Called if we need to clear a data reservation for this inode
4258  * Normally in a error case.
4259  *
4260  * This one will *NOT* use accurate qgroup reserved space API, just for case
4261  * which we can't sleep and is sure it won't affect qgroup reserved space.
4262  * Like clear_bit_hook().
4263  */
4264 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4265                                             u64 len)
4266 {
4267         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4268         struct btrfs_space_info *data_sinfo;
4269
4270         /* Make sure the range is aligned to sectorsize */
4271         len = round_up(start + len, fs_info->sectorsize) -
4272               round_down(start, fs_info->sectorsize);
4273         start = round_down(start, fs_info->sectorsize);
4274
4275         data_sinfo = fs_info->data_sinfo;
4276         spin_lock(&data_sinfo->lock);
4277         if (WARN_ON(data_sinfo->bytes_may_use < len))
4278                 data_sinfo->bytes_may_use = 0;
4279         else
4280                 data_sinfo->bytes_may_use -= len;
4281         trace_btrfs_space_reservation(fs_info, "space_info",
4282                                       data_sinfo->flags, len, 0);
4283         spin_unlock(&data_sinfo->lock);
4284 }
4285
4286 /*
4287  * Called if we need to clear a data reservation for this inode
4288  * Normally in a error case.
4289  *
4290  * This one will handle the per-inode data rsv map for accurate reserved
4291  * space framework.
4292  */
4293 void btrfs_free_reserved_data_space(struct inode *inode,
4294                         struct extent_changeset *reserved, u64 start, u64 len)
4295 {
4296         struct btrfs_root *root = BTRFS_I(inode)->root;
4297
4298         /* Make sure the range is aligned to sectorsize */
4299         len = round_up(start + len, root->fs_info->sectorsize) -
4300               round_down(start, root->fs_info->sectorsize);
4301         start = round_down(start, root->fs_info->sectorsize);
4302
4303         btrfs_free_reserved_data_space_noquota(inode, start, len);
4304         btrfs_qgroup_free_data(inode, reserved, start, len);
4305 }
4306
4307 static void force_metadata_allocation(struct btrfs_fs_info *info)
4308 {
4309         struct list_head *head = &info->space_info;
4310         struct btrfs_space_info *found;
4311
4312         rcu_read_lock();
4313         list_for_each_entry_rcu(found, head, list) {
4314                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4315                         found->force_alloc = CHUNK_ALLOC_FORCE;
4316         }
4317         rcu_read_unlock();
4318 }
4319
4320 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4321 {
4322         return (global->size << 1);
4323 }
4324
4325 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4326                               struct btrfs_space_info *sinfo, int force)
4327 {
4328         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4329         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4330         u64 thresh;
4331
4332         if (force == CHUNK_ALLOC_FORCE)
4333                 return 1;
4334
4335         /*
4336          * We need to take into account the global rsv because for all intents
4337          * and purposes it's used space.  Don't worry about locking the
4338          * global_rsv, it doesn't change except when the transaction commits.
4339          */
4340         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4341                 bytes_used += calc_global_rsv_need_space(global_rsv);
4342
4343         /*
4344          * in limited mode, we want to have some free space up to
4345          * about 1% of the FS size.
4346          */
4347         if (force == CHUNK_ALLOC_LIMITED) {
4348                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4349                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4350
4351                 if (sinfo->total_bytes - bytes_used < thresh)
4352                         return 1;
4353         }
4354
4355         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4356                 return 0;
4357         return 1;
4358 }
4359
4360 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4361 {
4362         u64 num_dev;
4363
4364         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4365                     BTRFS_BLOCK_GROUP_RAID0 |
4366                     BTRFS_BLOCK_GROUP_RAID5 |
4367                     BTRFS_BLOCK_GROUP_RAID6))
4368                 num_dev = fs_info->fs_devices->rw_devices;
4369         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4370                 num_dev = 2;
4371         else
4372                 num_dev = 1;    /* DUP or single */
4373
4374         return num_dev;
4375 }
4376
4377 /*
4378  * If @is_allocation is true, reserve space in the system space info necessary
4379  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4380  * removing a chunk.
4381  */
4382 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4383 {
4384         struct btrfs_fs_info *fs_info = trans->fs_info;
4385         struct btrfs_space_info *info;
4386         u64 left;
4387         u64 thresh;
4388         int ret = 0;
4389         u64 num_devs;
4390
4391         /*
4392          * Needed because we can end up allocating a system chunk and for an
4393          * atomic and race free space reservation in the chunk block reserve.
4394          */
4395         lockdep_assert_held(&fs_info->chunk_mutex);
4396
4397         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4398         spin_lock(&info->lock);
4399         left = info->total_bytes - btrfs_space_info_used(info, true);
4400         spin_unlock(&info->lock);
4401
4402         num_devs = get_profile_num_devs(fs_info, type);
4403
4404         /* num_devs device items to update and 1 chunk item to add or remove */
4405         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4406                 btrfs_calc_trans_metadata_size(fs_info, 1);
4407
4408         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4409                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4410                            left, thresh, type);
4411                 dump_space_info(fs_info, info, 0, 0);
4412         }
4413
4414         if (left < thresh) {
4415                 u64 flags = btrfs_system_alloc_profile(fs_info);
4416
4417                 /*
4418                  * Ignore failure to create system chunk. We might end up not
4419                  * needing it, as we might not need to COW all nodes/leafs from
4420                  * the paths we visit in the chunk tree (they were already COWed
4421                  * or created in the current transaction for example).
4422                  */
4423                 ret = btrfs_alloc_chunk(trans, flags);
4424         }
4425
4426         if (!ret) {
4427                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4428                                           &fs_info->chunk_block_rsv,
4429                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4430                 if (!ret)
4431                         trans->chunk_bytes_reserved += thresh;
4432         }
4433 }
4434
4435 /*
4436  * If force is CHUNK_ALLOC_FORCE:
4437  *    - return 1 if it successfully allocates a chunk,
4438  *    - return errors including -ENOSPC otherwise.
4439  * If force is NOT CHUNK_ALLOC_FORCE:
4440  *    - return 0 if it doesn't need to allocate a new chunk,
4441  *    - return 1 if it successfully allocates a chunk,
4442  *    - return errors including -ENOSPC otherwise.
4443  */
4444 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4445                           int force)
4446 {
4447         struct btrfs_fs_info *fs_info = trans->fs_info;
4448         struct btrfs_space_info *space_info;
4449         bool wait_for_alloc = false;
4450         bool should_alloc = false;
4451         int ret = 0;
4452
4453         /* Don't re-enter if we're already allocating a chunk */
4454         if (trans->allocating_chunk)
4455                 return -ENOSPC;
4456
4457         space_info = __find_space_info(fs_info, flags);
4458         ASSERT(space_info);
4459
4460         do {
4461                 spin_lock(&space_info->lock);
4462                 if (force < space_info->force_alloc)
4463                         force = space_info->force_alloc;
4464                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4465                 if (space_info->full) {
4466                         /* No more free physical space */
4467                         if (should_alloc)
4468                                 ret = -ENOSPC;
4469                         else
4470                                 ret = 0;
4471                         spin_unlock(&space_info->lock);
4472                         return ret;
4473                 } else if (!should_alloc) {
4474                         spin_unlock(&space_info->lock);
4475                         return 0;
4476                 } else if (space_info->chunk_alloc) {
4477                         /*
4478                          * Someone is already allocating, so we need to block
4479                          * until this someone is finished and then loop to
4480                          * recheck if we should continue with our allocation
4481                          * attempt.
4482                          */
4483                         wait_for_alloc = true;
4484                         spin_unlock(&space_info->lock);
4485                         mutex_lock(&fs_info->chunk_mutex);
4486                         mutex_unlock(&fs_info->chunk_mutex);
4487                 } else {
4488                         /* Proceed with allocation */
4489                         space_info->chunk_alloc = 1;
4490                         wait_for_alloc = false;
4491                         spin_unlock(&space_info->lock);
4492                 }
4493
4494                 cond_resched();
4495         } while (wait_for_alloc);
4496
4497         mutex_lock(&fs_info->chunk_mutex);
4498         trans->allocating_chunk = true;
4499
4500         /*
4501          * If we have mixed data/metadata chunks we want to make sure we keep
4502          * allocating mixed chunks instead of individual chunks.
4503          */
4504         if (btrfs_mixed_space_info(space_info))
4505                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4506
4507         /*
4508          * if we're doing a data chunk, go ahead and make sure that
4509          * we keep a reasonable number of metadata chunks allocated in the
4510          * FS as well.
4511          */
4512         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4513                 fs_info->data_chunk_allocations++;
4514                 if (!(fs_info->data_chunk_allocations %
4515                       fs_info->metadata_ratio))
4516                         force_metadata_allocation(fs_info);
4517         }
4518
4519         /*
4520          * Check if we have enough space in SYSTEM chunk because we may need
4521          * to update devices.
4522          */
4523         check_system_chunk(trans, flags);
4524
4525         ret = btrfs_alloc_chunk(trans, flags);
4526         trans->allocating_chunk = false;
4527
4528         spin_lock(&space_info->lock);
4529         if (ret < 0) {
4530                 if (ret == -ENOSPC)
4531                         space_info->full = 1;
4532                 else
4533                         goto out;
4534         } else {
4535                 ret = 1;
4536                 space_info->max_extent_size = 0;
4537         }
4538
4539         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4540 out:
4541         space_info->chunk_alloc = 0;
4542         spin_unlock(&space_info->lock);
4543         mutex_unlock(&fs_info->chunk_mutex);
4544         /*
4545          * When we allocate a new chunk we reserve space in the chunk block
4546          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4547          * add new nodes/leafs to it if we end up needing to do it when
4548          * inserting the chunk item and updating device items as part of the
4549          * second phase of chunk allocation, performed by
4550          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4551          * large number of new block groups to create in our transaction
4552          * handle's new_bgs list to avoid exhausting the chunk block reserve
4553          * in extreme cases - like having a single transaction create many new
4554          * block groups when starting to write out the free space caches of all
4555          * the block groups that were made dirty during the lifetime of the
4556          * transaction.
4557          */
4558         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
4559                 btrfs_create_pending_block_groups(trans);
4560
4561         return ret;
4562 }
4563
4564 static int can_overcommit(struct btrfs_fs_info *fs_info,
4565                           struct btrfs_space_info *space_info, u64 bytes,
4566                           enum btrfs_reserve_flush_enum flush,
4567                           bool system_chunk)
4568 {
4569         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4570         u64 profile;
4571         u64 space_size;
4572         u64 avail;
4573         u64 used;
4574         int factor;
4575
4576         /* Don't overcommit when in mixed mode. */
4577         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4578                 return 0;
4579
4580         if (system_chunk)
4581                 profile = btrfs_system_alloc_profile(fs_info);
4582         else
4583                 profile = btrfs_metadata_alloc_profile(fs_info);
4584
4585         used = btrfs_space_info_used(space_info, false);
4586
4587         /*
4588          * We only want to allow over committing if we have lots of actual space
4589          * free, but if we don't have enough space to handle the global reserve
4590          * space then we could end up having a real enospc problem when trying
4591          * to allocate a chunk or some other such important allocation.
4592          */
4593         spin_lock(&global_rsv->lock);
4594         space_size = calc_global_rsv_need_space(global_rsv);
4595         spin_unlock(&global_rsv->lock);
4596         if (used + space_size >= space_info->total_bytes)
4597                 return 0;
4598
4599         used += space_info->bytes_may_use;
4600
4601         avail = atomic64_read(&fs_info->free_chunk_space);
4602
4603         /*
4604          * If we have dup, raid1 or raid10 then only half of the free
4605          * space is actually useable.  For raid56, the space info used
4606          * doesn't include the parity drive, so we don't have to
4607          * change the math
4608          */
4609         factor = btrfs_bg_type_to_factor(profile);
4610         avail = div_u64(avail, factor);
4611
4612         /*
4613          * If we aren't flushing all things, let us overcommit up to
4614          * 1/2th of the space. If we can flush, don't let us overcommit
4615          * too much, let it overcommit up to 1/8 of the space.
4616          */
4617         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4618                 avail >>= 3;
4619         else
4620                 avail >>= 1;
4621
4622         if (used + bytes < space_info->total_bytes + avail)
4623                 return 1;
4624         return 0;
4625 }
4626
4627 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4628                                          unsigned long nr_pages, int nr_items)
4629 {
4630         struct super_block *sb = fs_info->sb;
4631
4632         if (down_read_trylock(&sb->s_umount)) {
4633                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4634                 up_read(&sb->s_umount);
4635         } else {
4636                 /*
4637                  * We needn't worry the filesystem going from r/w to r/o though
4638                  * we don't acquire ->s_umount mutex, because the filesystem
4639                  * should guarantee the delalloc inodes list be empty after
4640                  * the filesystem is readonly(all dirty pages are written to
4641                  * the disk).
4642                  */
4643                 btrfs_start_delalloc_roots(fs_info, nr_items);
4644                 if (!current->journal_info)
4645                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4646         }
4647 }
4648
4649 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4650                                         u64 to_reclaim)
4651 {
4652         u64 bytes;
4653         u64 nr;
4654
4655         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4656         nr = div64_u64(to_reclaim, bytes);
4657         if (!nr)
4658                 nr = 1;
4659         return nr;
4660 }
4661
4662 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4663
4664 /*
4665  * shrink metadata reservation for delalloc
4666  */
4667 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4668                             u64 orig, bool wait_ordered)
4669 {
4670         struct btrfs_space_info *space_info;
4671         struct btrfs_trans_handle *trans;
4672         u64 delalloc_bytes;
4673         u64 max_reclaim;
4674         u64 items;
4675         long time_left;
4676         unsigned long nr_pages;
4677         int loops;
4678
4679         /* Calc the number of the pages we need flush for space reservation */
4680         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4681         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4682
4683         trans = (struct btrfs_trans_handle *)current->journal_info;
4684         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4685
4686         delalloc_bytes = percpu_counter_sum_positive(
4687                                                 &fs_info->delalloc_bytes);
4688         if (delalloc_bytes == 0) {
4689                 if (trans)
4690                         return;
4691                 if (wait_ordered)
4692                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4693                 return;
4694         }
4695
4696         loops = 0;
4697         while (delalloc_bytes && loops < 3) {
4698                 max_reclaim = min(delalloc_bytes, to_reclaim);
4699                 nr_pages = max_reclaim >> PAGE_SHIFT;
4700                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4701                 /*
4702                  * We need to wait for the async pages to actually start before
4703                  * we do anything.
4704                  */
4705                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4706                 if (!max_reclaim)
4707                         goto skip_async;
4708
4709                 if (max_reclaim <= nr_pages)
4710                         max_reclaim = 0;
4711                 else
4712                         max_reclaim -= nr_pages;
4713
4714                 wait_event(fs_info->async_submit_wait,
4715                            atomic_read(&fs_info->async_delalloc_pages) <=
4716                            (int)max_reclaim);
4717 skip_async:
4718                 spin_lock(&space_info->lock);
4719                 if (list_empty(&space_info->tickets) &&
4720                     list_empty(&space_info->priority_tickets)) {
4721                         spin_unlock(&space_info->lock);
4722                         break;
4723                 }
4724                 spin_unlock(&space_info->lock);
4725
4726                 loops++;
4727                 if (wait_ordered && !trans) {
4728                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4729                 } else {
4730                         time_left = schedule_timeout_killable(1);
4731                         if (time_left)
4732                                 break;
4733                 }
4734                 delalloc_bytes = percpu_counter_sum_positive(
4735                                                 &fs_info->delalloc_bytes);
4736         }
4737 }
4738
4739 struct reserve_ticket {
4740         u64 bytes;
4741         int error;
4742         struct list_head list;
4743         wait_queue_head_t wait;
4744 };
4745
4746 /**
4747  * maybe_commit_transaction - possibly commit the transaction if its ok to
4748  * @root - the root we're allocating for
4749  * @bytes - the number of bytes we want to reserve
4750  * @force - force the commit
4751  *
4752  * This will check to make sure that committing the transaction will actually
4753  * get us somewhere and then commit the transaction if it does.  Otherwise it
4754  * will return -ENOSPC.
4755  */
4756 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4757                                   struct btrfs_space_info *space_info)
4758 {
4759         struct reserve_ticket *ticket = NULL;
4760         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4761         struct btrfs_trans_handle *trans;
4762         u64 bytes;
4763
4764         trans = (struct btrfs_trans_handle *)current->journal_info;
4765         if (trans)
4766                 return -EAGAIN;
4767
4768         spin_lock(&space_info->lock);
4769         if (!list_empty(&space_info->priority_tickets))
4770                 ticket = list_first_entry(&space_info->priority_tickets,
4771                                           struct reserve_ticket, list);
4772         else if (!list_empty(&space_info->tickets))
4773                 ticket = list_first_entry(&space_info->tickets,
4774                                           struct reserve_ticket, list);
4775         bytes = (ticket) ? ticket->bytes : 0;
4776         spin_unlock(&space_info->lock);
4777
4778         if (!bytes)
4779                 return 0;
4780
4781         /* See if there is enough pinned space to make this reservation */
4782         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4783                                    bytes,
4784                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0)
4785                 goto commit;
4786
4787         /*
4788          * See if there is some space in the delayed insertion reservation for
4789          * this reservation.
4790          */
4791         if (space_info != delayed_rsv->space_info)
4792                 return -ENOSPC;
4793
4794         spin_lock(&delayed_rsv->lock);
4795         if (delayed_rsv->size > bytes)
4796                 bytes = 0;
4797         else
4798                 bytes -= delayed_rsv->size;
4799         spin_unlock(&delayed_rsv->lock);
4800
4801         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4802                                    bytes,
4803                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0) {
4804                 return -ENOSPC;
4805         }
4806
4807 commit:
4808         trans = btrfs_join_transaction(fs_info->extent_root);
4809         if (IS_ERR(trans))
4810                 return -ENOSPC;
4811
4812         return btrfs_commit_transaction(trans);
4813 }
4814
4815 /*
4816  * Try to flush some data based on policy set by @state. This is only advisory
4817  * and may fail for various reasons. The caller is supposed to examine the
4818  * state of @space_info to detect the outcome.
4819  */
4820 static void flush_space(struct btrfs_fs_info *fs_info,
4821                        struct btrfs_space_info *space_info, u64 num_bytes,
4822                        int state)
4823 {
4824         struct btrfs_root *root = fs_info->extent_root;
4825         struct btrfs_trans_handle *trans;
4826         int nr;
4827         int ret = 0;
4828
4829         switch (state) {
4830         case FLUSH_DELAYED_ITEMS_NR:
4831         case FLUSH_DELAYED_ITEMS:
4832                 if (state == FLUSH_DELAYED_ITEMS_NR)
4833                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4834                 else
4835                         nr = -1;
4836
4837                 trans = btrfs_join_transaction(root);
4838                 if (IS_ERR(trans)) {
4839                         ret = PTR_ERR(trans);
4840                         break;
4841                 }
4842                 ret = btrfs_run_delayed_items_nr(trans, nr);
4843                 btrfs_end_transaction(trans);
4844                 break;
4845         case FLUSH_DELALLOC:
4846         case FLUSH_DELALLOC_WAIT:
4847                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4848                                 state == FLUSH_DELALLOC_WAIT);
4849                 break;
4850         case ALLOC_CHUNK:
4851                 trans = btrfs_join_transaction(root);
4852                 if (IS_ERR(trans)) {
4853                         ret = PTR_ERR(trans);
4854                         break;
4855                 }
4856                 ret = do_chunk_alloc(trans,
4857                                      btrfs_metadata_alloc_profile(fs_info),
4858                                      CHUNK_ALLOC_NO_FORCE);
4859                 btrfs_end_transaction(trans);
4860                 if (ret > 0 || ret == -ENOSPC)
4861                         ret = 0;
4862                 break;
4863         case COMMIT_TRANS:
4864                 ret = may_commit_transaction(fs_info, space_info);
4865                 break;
4866         default:
4867                 ret = -ENOSPC;
4868                 break;
4869         }
4870
4871         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
4872                                 ret);
4873         return;
4874 }
4875
4876 static inline u64
4877 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
4878                                  struct btrfs_space_info *space_info,
4879                                  bool system_chunk)
4880 {
4881         struct reserve_ticket *ticket;
4882         u64 used;
4883         u64 expected;
4884         u64 to_reclaim = 0;
4885
4886         list_for_each_entry(ticket, &space_info->tickets, list)
4887                 to_reclaim += ticket->bytes;
4888         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4889                 to_reclaim += ticket->bytes;
4890         if (to_reclaim)
4891                 return to_reclaim;
4892
4893         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4894         if (can_overcommit(fs_info, space_info, to_reclaim,
4895                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4896                 return 0;
4897
4898         used = btrfs_space_info_used(space_info, true);
4899
4900         if (can_overcommit(fs_info, space_info, SZ_1M,
4901                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4902                 expected = div_factor_fine(space_info->total_bytes, 95);
4903         else
4904                 expected = div_factor_fine(space_info->total_bytes, 90);
4905
4906         if (used > expected)
4907                 to_reclaim = used - expected;
4908         else
4909                 to_reclaim = 0;
4910         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4911                                      space_info->bytes_reserved);
4912         return to_reclaim;
4913 }
4914
4915 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
4916                                         struct btrfs_space_info *space_info,
4917                                         u64 used, bool system_chunk)
4918 {
4919         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4920
4921         /* If we're just plain full then async reclaim just slows us down. */
4922         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4923                 return 0;
4924
4925         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4926                                               system_chunk))
4927                 return 0;
4928
4929         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4930                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4931 }
4932
4933 static void wake_all_tickets(struct list_head *head)
4934 {
4935         struct reserve_ticket *ticket;
4936
4937         while (!list_empty(head)) {
4938                 ticket = list_first_entry(head, struct reserve_ticket, list);
4939                 list_del_init(&ticket->list);
4940                 ticket->error = -ENOSPC;
4941                 wake_up(&ticket->wait);
4942         }
4943 }
4944
4945 /*
4946  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4947  * will loop and continuously try to flush as long as we are making progress.
4948  * We count progress as clearing off tickets each time we have to loop.
4949  */
4950 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4951 {
4952         struct btrfs_fs_info *fs_info;
4953         struct btrfs_space_info *space_info;
4954         u64 to_reclaim;
4955         int flush_state;
4956         int commit_cycles = 0;
4957         u64 last_tickets_id;
4958
4959         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4960         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4961
4962         spin_lock(&space_info->lock);
4963         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4964                                                       false);
4965         if (!to_reclaim) {
4966                 space_info->flush = 0;
4967                 spin_unlock(&space_info->lock);
4968                 return;
4969         }
4970         last_tickets_id = space_info->tickets_id;
4971         spin_unlock(&space_info->lock);
4972
4973         flush_state = FLUSH_DELAYED_ITEMS_NR;
4974         do {
4975                 flush_space(fs_info, space_info, to_reclaim, flush_state);
4976                 spin_lock(&space_info->lock);
4977                 if (list_empty(&space_info->tickets)) {
4978                         space_info->flush = 0;
4979                         spin_unlock(&space_info->lock);
4980                         return;
4981                 }
4982                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
4983                                                               space_info,
4984                                                               false);
4985                 if (last_tickets_id == space_info->tickets_id) {
4986                         flush_state++;
4987                 } else {
4988                         last_tickets_id = space_info->tickets_id;
4989                         flush_state = FLUSH_DELAYED_ITEMS_NR;
4990                         if (commit_cycles)
4991                                 commit_cycles--;
4992                 }
4993
4994                 if (flush_state > COMMIT_TRANS) {
4995                         commit_cycles++;
4996                         if (commit_cycles > 2) {
4997                                 wake_all_tickets(&space_info->tickets);
4998                                 space_info->flush = 0;
4999                         } else {
5000                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5001                         }
5002                 }
5003                 spin_unlock(&space_info->lock);
5004         } while (flush_state <= COMMIT_TRANS);
5005 }
5006
5007 void btrfs_init_async_reclaim_work(struct work_struct *work)
5008 {
5009         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5010 }
5011
5012 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5013                                             struct btrfs_space_info *space_info,
5014                                             struct reserve_ticket *ticket)
5015 {
5016         u64 to_reclaim;
5017         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5018
5019         spin_lock(&space_info->lock);
5020         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5021                                                       false);
5022         if (!to_reclaim) {
5023                 spin_unlock(&space_info->lock);
5024                 return;
5025         }
5026         spin_unlock(&space_info->lock);
5027
5028         do {
5029                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5030                 flush_state++;
5031                 spin_lock(&space_info->lock);
5032                 if (ticket->bytes == 0) {
5033                         spin_unlock(&space_info->lock);
5034                         return;
5035                 }
5036                 spin_unlock(&space_info->lock);
5037
5038                 /*
5039                  * Priority flushers can't wait on delalloc without
5040                  * deadlocking.
5041                  */
5042                 if (flush_state == FLUSH_DELALLOC ||
5043                     flush_state == FLUSH_DELALLOC_WAIT)
5044                         flush_state = ALLOC_CHUNK;
5045         } while (flush_state < COMMIT_TRANS);
5046 }
5047
5048 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5049                                struct btrfs_space_info *space_info,
5050                                struct reserve_ticket *ticket, u64 orig_bytes)
5051
5052 {
5053         DEFINE_WAIT(wait);
5054         int ret = 0;
5055
5056         spin_lock(&space_info->lock);
5057         while (ticket->bytes > 0 && ticket->error == 0) {
5058                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5059                 if (ret) {
5060                         ret = -EINTR;
5061                         break;
5062                 }
5063                 spin_unlock(&space_info->lock);
5064
5065                 schedule();
5066
5067                 finish_wait(&ticket->wait, &wait);
5068                 spin_lock(&space_info->lock);
5069         }
5070         if (!ret)
5071                 ret = ticket->error;
5072         if (!list_empty(&ticket->list))
5073                 list_del_init(&ticket->list);
5074         if (ticket->bytes && ticket->bytes < orig_bytes) {
5075                 u64 num_bytes = orig_bytes - ticket->bytes;
5076                 space_info->bytes_may_use -= num_bytes;
5077                 trace_btrfs_space_reservation(fs_info, "space_info",
5078                                               space_info->flags, num_bytes, 0);
5079         }
5080         spin_unlock(&space_info->lock);
5081
5082         return ret;
5083 }
5084
5085 /**
5086  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5087  * @root - the root we're allocating for
5088  * @space_info - the space info we want to allocate from
5089  * @orig_bytes - the number of bytes we want
5090  * @flush - whether or not we can flush to make our reservation
5091  *
5092  * This will reserve orig_bytes number of bytes from the space info associated
5093  * with the block_rsv.  If there is not enough space it will make an attempt to
5094  * flush out space to make room.  It will do this by flushing delalloc if
5095  * possible or committing the transaction.  If flush is 0 then no attempts to
5096  * regain reservations will be made and this will fail if there is not enough
5097  * space already.
5098  */
5099 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5100                                     struct btrfs_space_info *space_info,
5101                                     u64 orig_bytes,
5102                                     enum btrfs_reserve_flush_enum flush,
5103                                     bool system_chunk)
5104 {
5105         struct reserve_ticket ticket;
5106         u64 used;
5107         int ret = 0;
5108
5109         ASSERT(orig_bytes);
5110         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5111
5112         spin_lock(&space_info->lock);
5113         ret = -ENOSPC;
5114         used = btrfs_space_info_used(space_info, true);
5115
5116         /*
5117          * If we have enough space then hooray, make our reservation and carry
5118          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5119          * If not things get more complicated.
5120          */
5121         if (used + orig_bytes <= space_info->total_bytes) {
5122                 space_info->bytes_may_use += orig_bytes;
5123                 trace_btrfs_space_reservation(fs_info, "space_info",
5124                                               space_info->flags, orig_bytes, 1);
5125                 ret = 0;
5126         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5127                                   system_chunk)) {
5128                 space_info->bytes_may_use += orig_bytes;
5129                 trace_btrfs_space_reservation(fs_info, "space_info",
5130                                               space_info->flags, orig_bytes, 1);
5131                 ret = 0;
5132         }
5133
5134         /*
5135          * If we couldn't make a reservation then setup our reservation ticket
5136          * and kick the async worker if it's not already running.
5137          *
5138          * If we are a priority flusher then we just need to add our ticket to
5139          * the list and we will do our own flushing further down.
5140          */
5141         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5142                 ticket.bytes = orig_bytes;
5143                 ticket.error = 0;
5144                 init_waitqueue_head(&ticket.wait);
5145                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5146                         list_add_tail(&ticket.list, &space_info->tickets);
5147                         if (!space_info->flush) {
5148                                 space_info->flush = 1;
5149                                 trace_btrfs_trigger_flush(fs_info,
5150                                                           space_info->flags,
5151                                                           orig_bytes, flush,
5152                                                           "enospc");
5153                                 queue_work(system_unbound_wq,
5154                                            &fs_info->async_reclaim_work);
5155                         }
5156                 } else {
5157                         list_add_tail(&ticket.list,
5158                                       &space_info->priority_tickets);
5159                 }
5160         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5161                 used += orig_bytes;
5162                 /*
5163                  * We will do the space reservation dance during log replay,
5164                  * which means we won't have fs_info->fs_root set, so don't do
5165                  * the async reclaim as we will panic.
5166                  */
5167                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5168                     need_do_async_reclaim(fs_info, space_info,
5169                                           used, system_chunk) &&
5170                     !work_busy(&fs_info->async_reclaim_work)) {
5171                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5172                                                   orig_bytes, flush, "preempt");
5173                         queue_work(system_unbound_wq,
5174                                    &fs_info->async_reclaim_work);
5175                 }
5176         }
5177         spin_unlock(&space_info->lock);
5178         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5179                 return ret;
5180
5181         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5182                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5183                                            orig_bytes);
5184
5185         ret = 0;
5186         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5187         spin_lock(&space_info->lock);
5188         if (ticket.bytes) {
5189                 if (ticket.bytes < orig_bytes) {
5190                         u64 num_bytes = orig_bytes - ticket.bytes;
5191                         space_info->bytes_may_use -= num_bytes;
5192                         trace_btrfs_space_reservation(fs_info, "space_info",
5193                                                       space_info->flags,
5194                                                       num_bytes, 0);
5195
5196                 }
5197                 list_del_init(&ticket.list);
5198                 ret = -ENOSPC;
5199         }
5200         spin_unlock(&space_info->lock);
5201         ASSERT(list_empty(&ticket.list));
5202         return ret;
5203 }
5204
5205 /**
5206  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5207  * @root - the root we're allocating for
5208  * @block_rsv - the block_rsv we're allocating for
5209  * @orig_bytes - the number of bytes we want
5210  * @flush - whether or not we can flush to make our reservation
5211  *
5212  * This will reserve orgi_bytes number of bytes from the space info associated
5213  * with the block_rsv.  If there is not enough space it will make an attempt to
5214  * flush out space to make room.  It will do this by flushing delalloc if
5215  * possible or committing the transaction.  If flush is 0 then no attempts to
5216  * regain reservations will be made and this will fail if there is not enough
5217  * space already.
5218  */
5219 static int reserve_metadata_bytes(struct btrfs_root *root,
5220                                   struct btrfs_block_rsv *block_rsv,
5221                                   u64 orig_bytes,
5222                                   enum btrfs_reserve_flush_enum flush)
5223 {
5224         struct btrfs_fs_info *fs_info = root->fs_info;
5225         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5226         int ret;
5227         bool system_chunk = (root == fs_info->chunk_root);
5228
5229         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5230                                        orig_bytes, flush, system_chunk);
5231         if (ret == -ENOSPC &&
5232             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5233                 if (block_rsv != global_rsv &&
5234                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5235                         ret = 0;
5236         }
5237         if (ret == -ENOSPC) {
5238                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5239                                               block_rsv->space_info->flags,
5240                                               orig_bytes, 1);
5241
5242                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5243                         dump_space_info(fs_info, block_rsv->space_info,
5244                                         orig_bytes, 0);
5245         }
5246         return ret;
5247 }
5248
5249 static struct btrfs_block_rsv *get_block_rsv(
5250                                         const struct btrfs_trans_handle *trans,
5251                                         const struct btrfs_root *root)
5252 {
5253         struct btrfs_fs_info *fs_info = root->fs_info;
5254         struct btrfs_block_rsv *block_rsv = NULL;
5255
5256         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5257             (root == fs_info->csum_root && trans->adding_csums) ||
5258             (root == fs_info->uuid_root))
5259                 block_rsv = trans->block_rsv;
5260
5261         if (!block_rsv)
5262                 block_rsv = root->block_rsv;
5263
5264         if (!block_rsv)
5265                 block_rsv = &fs_info->empty_block_rsv;
5266
5267         return block_rsv;
5268 }
5269
5270 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5271                                u64 num_bytes)
5272 {
5273         int ret = -ENOSPC;
5274         spin_lock(&block_rsv->lock);
5275         if (block_rsv->reserved >= num_bytes) {
5276                 block_rsv->reserved -= num_bytes;
5277                 if (block_rsv->reserved < block_rsv->size)
5278                         block_rsv->full = 0;
5279                 ret = 0;
5280         }
5281         spin_unlock(&block_rsv->lock);
5282         return ret;
5283 }
5284
5285 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5286                                 u64 num_bytes, int update_size)
5287 {
5288         spin_lock(&block_rsv->lock);
5289         block_rsv->reserved += num_bytes;
5290         if (update_size)
5291                 block_rsv->size += num_bytes;
5292         else if (block_rsv->reserved >= block_rsv->size)
5293                 block_rsv->full = 1;
5294         spin_unlock(&block_rsv->lock);
5295 }
5296
5297 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5298                              struct btrfs_block_rsv *dest, u64 num_bytes,
5299                              int min_factor)
5300 {
5301         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5302         u64 min_bytes;
5303
5304         if (global_rsv->space_info != dest->space_info)
5305                 return -ENOSPC;
5306
5307         spin_lock(&global_rsv->lock);
5308         min_bytes = div_factor(global_rsv->size, min_factor);
5309         if (global_rsv->reserved < min_bytes + num_bytes) {
5310                 spin_unlock(&global_rsv->lock);
5311                 return -ENOSPC;
5312         }
5313         global_rsv->reserved -= num_bytes;
5314         if (global_rsv->reserved < global_rsv->size)
5315                 global_rsv->full = 0;
5316         spin_unlock(&global_rsv->lock);
5317
5318         block_rsv_add_bytes(dest, num_bytes, 1);
5319         return 0;
5320 }
5321
5322 /*
5323  * This is for space we already have accounted in space_info->bytes_may_use, so
5324  * basically when we're returning space from block_rsv's.
5325  */
5326 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5327                                      struct btrfs_space_info *space_info,
5328                                      u64 num_bytes)
5329 {
5330         struct reserve_ticket *ticket;
5331         struct list_head *head;
5332         u64 used;
5333         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5334         bool check_overcommit = false;
5335
5336         spin_lock(&space_info->lock);
5337         head = &space_info->priority_tickets;
5338
5339         /*
5340          * If we are over our limit then we need to check and see if we can
5341          * overcommit, and if we can't then we just need to free up our space
5342          * and not satisfy any requests.
5343          */
5344         used = btrfs_space_info_used(space_info, true);
5345         if (used - num_bytes >= space_info->total_bytes)
5346                 check_overcommit = true;
5347 again:
5348         while (!list_empty(head) && num_bytes) {
5349                 ticket = list_first_entry(head, struct reserve_ticket,
5350                                           list);
5351                 /*
5352                  * We use 0 bytes because this space is already reserved, so
5353                  * adding the ticket space would be a double count.
5354                  */
5355                 if (check_overcommit &&
5356                     !can_overcommit(fs_info, space_info, 0, flush, false))
5357                         break;
5358                 if (num_bytes >= ticket->bytes) {
5359                         list_del_init(&ticket->list);
5360                         num_bytes -= ticket->bytes;
5361                         ticket->bytes = 0;
5362                         space_info->tickets_id++;
5363                         wake_up(&ticket->wait);
5364                 } else {
5365                         ticket->bytes -= num_bytes;
5366                         num_bytes = 0;
5367                 }
5368         }
5369
5370         if (num_bytes && head == &space_info->priority_tickets) {
5371                 head = &space_info->tickets;
5372                 flush = BTRFS_RESERVE_FLUSH_ALL;
5373                 goto again;
5374         }
5375         space_info->bytes_may_use -= num_bytes;
5376         trace_btrfs_space_reservation(fs_info, "space_info",
5377                                       space_info->flags, num_bytes, 0);
5378         spin_unlock(&space_info->lock);
5379 }
5380
5381 /*
5382  * This is for newly allocated space that isn't accounted in
5383  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5384  * we use this helper.
5385  */
5386 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5387                                      struct btrfs_space_info *space_info,
5388                                      u64 num_bytes)
5389 {
5390         struct reserve_ticket *ticket;
5391         struct list_head *head = &space_info->priority_tickets;
5392
5393 again:
5394         while (!list_empty(head) && num_bytes) {
5395                 ticket = list_first_entry(head, struct reserve_ticket,
5396                                           list);
5397                 if (num_bytes >= ticket->bytes) {
5398                         trace_btrfs_space_reservation(fs_info, "space_info",
5399                                                       space_info->flags,
5400                                                       ticket->bytes, 1);
5401                         list_del_init(&ticket->list);
5402                         num_bytes -= ticket->bytes;
5403                         space_info->bytes_may_use += ticket->bytes;
5404                         ticket->bytes = 0;
5405                         space_info->tickets_id++;
5406                         wake_up(&ticket->wait);
5407                 } else {
5408                         trace_btrfs_space_reservation(fs_info, "space_info",
5409                                                       space_info->flags,
5410                                                       num_bytes, 1);
5411                         space_info->bytes_may_use += num_bytes;
5412                         ticket->bytes -= num_bytes;
5413                         num_bytes = 0;
5414                 }
5415         }
5416
5417         if (num_bytes && head == &space_info->priority_tickets) {
5418                 head = &space_info->tickets;
5419                 goto again;
5420         }
5421 }
5422
5423 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5424                                     struct btrfs_block_rsv *block_rsv,
5425                                     struct btrfs_block_rsv *dest, u64 num_bytes,
5426                                     u64 *qgroup_to_release_ret)
5427 {
5428         struct btrfs_space_info *space_info = block_rsv->space_info;
5429         u64 qgroup_to_release = 0;
5430         u64 ret;
5431
5432         spin_lock(&block_rsv->lock);
5433         if (num_bytes == (u64)-1) {
5434                 num_bytes = block_rsv->size;
5435                 qgroup_to_release = block_rsv->qgroup_rsv_size;
5436         }
5437         block_rsv->size -= num_bytes;
5438         if (block_rsv->reserved >= block_rsv->size) {
5439                 num_bytes = block_rsv->reserved - block_rsv->size;
5440                 block_rsv->reserved = block_rsv->size;
5441                 block_rsv->full = 1;
5442         } else {
5443                 num_bytes = 0;
5444         }
5445         if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
5446                 qgroup_to_release = block_rsv->qgroup_rsv_reserved -
5447                                     block_rsv->qgroup_rsv_size;
5448                 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
5449         } else {
5450                 qgroup_to_release = 0;
5451         }
5452         spin_unlock(&block_rsv->lock);
5453
5454         ret = num_bytes;
5455         if (num_bytes > 0) {
5456                 if (dest) {
5457                         spin_lock(&dest->lock);
5458                         if (!dest->full) {
5459                                 u64 bytes_to_add;
5460
5461                                 bytes_to_add = dest->size - dest->reserved;
5462                                 bytes_to_add = min(num_bytes, bytes_to_add);
5463                                 dest->reserved += bytes_to_add;
5464                                 if (dest->reserved >= dest->size)
5465                                         dest->full = 1;
5466                                 num_bytes -= bytes_to_add;
5467                         }
5468                         spin_unlock(&dest->lock);
5469                 }
5470                 if (num_bytes)
5471                         space_info_add_old_bytes(fs_info, space_info,
5472                                                  num_bytes);
5473         }
5474         if (qgroup_to_release_ret)
5475                 *qgroup_to_release_ret = qgroup_to_release;
5476         return ret;
5477 }
5478
5479 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5480                             struct btrfs_block_rsv *dst, u64 num_bytes,
5481                             int update_size)
5482 {
5483         int ret;
5484
5485         ret = block_rsv_use_bytes(src, num_bytes);
5486         if (ret)
5487                 return ret;
5488
5489         block_rsv_add_bytes(dst, num_bytes, update_size);
5490         return 0;
5491 }
5492
5493 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5494 {
5495         memset(rsv, 0, sizeof(*rsv));
5496         spin_lock_init(&rsv->lock);
5497         rsv->type = type;
5498 }
5499
5500 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5501                                    struct btrfs_block_rsv *rsv,
5502                                    unsigned short type)
5503 {
5504         btrfs_init_block_rsv(rsv, type);
5505         rsv->space_info = __find_space_info(fs_info,
5506                                             BTRFS_BLOCK_GROUP_METADATA);
5507 }
5508
5509 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5510                                               unsigned short type)
5511 {
5512         struct btrfs_block_rsv *block_rsv;
5513
5514         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5515         if (!block_rsv)
5516                 return NULL;
5517
5518         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5519         return block_rsv;
5520 }
5521
5522 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5523                           struct btrfs_block_rsv *rsv)
5524 {
5525         if (!rsv)
5526                 return;
5527         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5528         kfree(rsv);
5529 }
5530
5531 int btrfs_block_rsv_add(struct btrfs_root *root,
5532                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5533                         enum btrfs_reserve_flush_enum flush)
5534 {
5535         int ret;
5536
5537         if (num_bytes == 0)
5538                 return 0;
5539
5540         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5541         if (!ret) {
5542                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5543                 return 0;
5544         }
5545
5546         return ret;
5547 }
5548
5549 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5550 {
5551         u64 num_bytes = 0;
5552         int ret = -ENOSPC;
5553
5554         if (!block_rsv)
5555                 return 0;
5556
5557         spin_lock(&block_rsv->lock);
5558         num_bytes = div_factor(block_rsv->size, min_factor);
5559         if (block_rsv->reserved >= num_bytes)
5560                 ret = 0;
5561         spin_unlock(&block_rsv->lock);
5562
5563         return ret;
5564 }
5565
5566 int btrfs_block_rsv_refill(struct btrfs_root *root,
5567                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5568                            enum btrfs_reserve_flush_enum flush)
5569 {
5570         u64 num_bytes = 0;
5571         int ret = -ENOSPC;
5572
5573         if (!block_rsv)
5574                 return 0;
5575
5576         spin_lock(&block_rsv->lock);
5577         num_bytes = min_reserved;
5578         if (block_rsv->reserved >= num_bytes)
5579                 ret = 0;
5580         else
5581                 num_bytes -= block_rsv->reserved;
5582         spin_unlock(&block_rsv->lock);
5583
5584         if (!ret)
5585                 return 0;
5586
5587         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5588         if (!ret) {
5589                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5590                 return 0;
5591         }
5592
5593         return ret;
5594 }
5595
5596 /**
5597  * btrfs_inode_rsv_refill - refill the inode block rsv.
5598  * @inode - the inode we are refilling.
5599  * @flush - the flusing restriction.
5600  *
5601  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5602  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5603  * or return if we already have enough space.  This will also handle the resreve
5604  * tracepoint for the reserved amount.
5605  */
5606 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5607                                   enum btrfs_reserve_flush_enum flush)
5608 {
5609         struct btrfs_root *root = inode->root;
5610         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5611         u64 num_bytes = 0;
5612         u64 qgroup_num_bytes = 0;
5613         int ret = -ENOSPC;
5614
5615         spin_lock(&block_rsv->lock);
5616         if (block_rsv->reserved < block_rsv->size)
5617                 num_bytes = block_rsv->size - block_rsv->reserved;
5618         if (block_rsv->qgroup_rsv_reserved < block_rsv->qgroup_rsv_size)
5619                 qgroup_num_bytes = block_rsv->qgroup_rsv_size -
5620                                    block_rsv->qgroup_rsv_reserved;
5621         spin_unlock(&block_rsv->lock);
5622
5623         if (num_bytes == 0)
5624                 return 0;
5625
5626         ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_num_bytes, true);
5627         if (ret)
5628                 return ret;
5629         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5630         if (!ret) {
5631                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5632                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5633                                               btrfs_ino(inode), num_bytes, 1);
5634
5635                 /* Don't forget to increase qgroup_rsv_reserved */
5636                 spin_lock(&block_rsv->lock);
5637                 block_rsv->qgroup_rsv_reserved += qgroup_num_bytes;
5638                 spin_unlock(&block_rsv->lock);
5639         } else
5640                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5641         return ret;
5642 }
5643
5644 /**
5645  * btrfs_inode_rsv_release - release any excessive reservation.
5646  * @inode - the inode we need to release from.
5647  * @qgroup_free - free or convert qgroup meta.
5648  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5649  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5650  *   @qgroup_free is true for error handling, and false for normal release.
5651  *
5652  * This is the same as btrfs_block_rsv_release, except that it handles the
5653  * tracepoint for the reservation.
5654  */
5655 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5656 {
5657         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5658         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5659         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5660         u64 released = 0;
5661         u64 qgroup_to_release = 0;
5662
5663         /*
5664          * Since we statically set the block_rsv->size we just want to say we
5665          * are releasing 0 bytes, and then we'll just get the reservation over
5666          * the size free'd.
5667          */
5668         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0,
5669                                            &qgroup_to_release);
5670         if (released > 0)
5671                 trace_btrfs_space_reservation(fs_info, "delalloc",
5672                                               btrfs_ino(inode), released, 0);
5673         if (qgroup_free)
5674                 btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release);
5675         else
5676                 btrfs_qgroup_convert_reserved_meta(inode->root,
5677                                                    qgroup_to_release);
5678 }
5679
5680 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5681                              struct btrfs_block_rsv *block_rsv,
5682                              u64 num_bytes)
5683 {
5684         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5685
5686         if (global_rsv == block_rsv ||
5687             block_rsv->space_info != global_rsv->space_info)
5688                 global_rsv = NULL;
5689         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes, NULL);
5690 }
5691
5692 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5693 {
5694         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5695         struct btrfs_space_info *sinfo = block_rsv->space_info;
5696         u64 num_bytes;
5697
5698         /*
5699          * The global block rsv is based on the size of the extent tree, the
5700          * checksum tree and the root tree.  If the fs is empty we want to set
5701          * it to a minimal amount for safety.
5702          */
5703         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5704                 btrfs_root_used(&fs_info->csum_root->root_item) +
5705                 btrfs_root_used(&fs_info->tree_root->root_item);
5706         num_bytes = max_t(u64, num_bytes, SZ_16M);
5707
5708         spin_lock(&sinfo->lock);
5709         spin_lock(&block_rsv->lock);
5710
5711         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5712
5713         if (block_rsv->reserved < block_rsv->size) {
5714                 num_bytes = btrfs_space_info_used(sinfo, true);
5715                 if (sinfo->total_bytes > num_bytes) {
5716                         num_bytes = sinfo->total_bytes - num_bytes;
5717                         num_bytes = min(num_bytes,
5718                                         block_rsv->size - block_rsv->reserved);
5719                         block_rsv->reserved += num_bytes;
5720                         sinfo->bytes_may_use += num_bytes;
5721                         trace_btrfs_space_reservation(fs_info, "space_info",
5722                                                       sinfo->flags, num_bytes,
5723                                                       1);
5724                 }
5725         } else if (block_rsv->reserved > block_rsv->size) {
5726                 num_bytes = block_rsv->reserved - block_rsv->size;
5727                 sinfo->bytes_may_use -= num_bytes;
5728                 trace_btrfs_space_reservation(fs_info, "space_info",
5729                                       sinfo->flags, num_bytes, 0);
5730                 block_rsv->reserved = block_rsv->size;
5731         }
5732
5733         if (block_rsv->reserved == block_rsv->size)
5734                 block_rsv->full = 1;
5735         else
5736                 block_rsv->full = 0;
5737
5738         spin_unlock(&block_rsv->lock);
5739         spin_unlock(&sinfo->lock);
5740 }
5741
5742 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5743 {
5744         struct btrfs_space_info *space_info;
5745
5746         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5747         fs_info->chunk_block_rsv.space_info = space_info;
5748
5749         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5750         fs_info->global_block_rsv.space_info = space_info;
5751         fs_info->trans_block_rsv.space_info = space_info;
5752         fs_info->empty_block_rsv.space_info = space_info;
5753         fs_info->delayed_block_rsv.space_info = space_info;
5754
5755         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5756         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5757         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5758         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5759         if (fs_info->quota_root)
5760                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5761         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5762
5763         update_global_block_rsv(fs_info);
5764 }
5765
5766 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5767 {
5768         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5769                                 (u64)-1, NULL);
5770         WARN_ON(fs_info->trans_block_rsv.size > 0);
5771         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5772         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5773         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5774         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5775         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5776 }
5777
5778
5779 /*
5780  * To be called after all the new block groups attached to the transaction
5781  * handle have been created (btrfs_create_pending_block_groups()).
5782  */
5783 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5784 {
5785         struct btrfs_fs_info *fs_info = trans->fs_info;
5786
5787         if (!trans->chunk_bytes_reserved)
5788                 return;
5789
5790         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5791
5792         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5793                                 trans->chunk_bytes_reserved, NULL);
5794         trans->chunk_bytes_reserved = 0;
5795 }
5796
5797 /*
5798  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5799  * root: the root of the parent directory
5800  * rsv: block reservation
5801  * items: the number of items that we need do reservation
5802  * use_global_rsv: allow fallback to the global block reservation
5803  *
5804  * This function is used to reserve the space for snapshot/subvolume
5805  * creation and deletion. Those operations are different with the
5806  * common file/directory operations, they change two fs/file trees
5807  * and root tree, the number of items that the qgroup reserves is
5808  * different with the free space reservation. So we can not use
5809  * the space reservation mechanism in start_transaction().
5810  */
5811 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5812                                      struct btrfs_block_rsv *rsv, int items,
5813                                      bool use_global_rsv)
5814 {
5815         u64 qgroup_num_bytes = 0;
5816         u64 num_bytes;
5817         int ret;
5818         struct btrfs_fs_info *fs_info = root->fs_info;
5819         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5820
5821         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5822                 /* One for parent inode, two for dir entries */
5823                 qgroup_num_bytes = 3 * fs_info->nodesize;
5824                 ret = btrfs_qgroup_reserve_meta_prealloc(root,
5825                                 qgroup_num_bytes, true);
5826                 if (ret)
5827                         return ret;
5828         }
5829
5830         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5831         rsv->space_info = __find_space_info(fs_info,
5832                                             BTRFS_BLOCK_GROUP_METADATA);
5833         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5834                                   BTRFS_RESERVE_FLUSH_ALL);
5835
5836         if (ret == -ENOSPC && use_global_rsv)
5837                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5838
5839         if (ret && qgroup_num_bytes)
5840                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5841
5842         return ret;
5843 }
5844
5845 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5846                                       struct btrfs_block_rsv *rsv)
5847 {
5848         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5849 }
5850
5851 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
5852                                                  struct btrfs_inode *inode)
5853 {
5854         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5855         u64 reserve_size = 0;
5856         u64 qgroup_rsv_size = 0;
5857         u64 csum_leaves;
5858         unsigned outstanding_extents;
5859
5860         lockdep_assert_held(&inode->lock);
5861         outstanding_extents = inode->outstanding_extents;
5862         if (outstanding_extents)
5863                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
5864                                                 outstanding_extents + 1);
5865         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
5866                                                  inode->csum_bytes);
5867         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
5868                                                        csum_leaves);
5869         /*
5870          * For qgroup rsv, the calculation is very simple:
5871          * account one nodesize for each outstanding extent
5872          *
5873          * This is overestimating in most cases.
5874          */
5875         qgroup_rsv_size = outstanding_extents * fs_info->nodesize;
5876
5877         spin_lock(&block_rsv->lock);
5878         block_rsv->size = reserve_size;
5879         block_rsv->qgroup_rsv_size = qgroup_rsv_size;
5880         spin_unlock(&block_rsv->lock);
5881 }
5882
5883 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
5884 {
5885         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5886         unsigned nr_extents;
5887         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5888         int ret = 0;
5889         bool delalloc_lock = true;
5890
5891         /* If we are a free space inode we need to not flush since we will be in
5892          * the middle of a transaction commit.  We also don't need the delalloc
5893          * mutex since we won't race with anybody.  We need this mostly to make
5894          * lockdep shut its filthy mouth.
5895          *
5896          * If we have a transaction open (can happen if we call truncate_block
5897          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5898          */
5899         if (btrfs_is_free_space_inode(inode)) {
5900                 flush = BTRFS_RESERVE_NO_FLUSH;
5901                 delalloc_lock = false;
5902         } else {
5903                 if (current->journal_info)
5904                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
5905
5906                 if (btrfs_transaction_in_commit(fs_info))
5907                         schedule_timeout(1);
5908         }
5909
5910         if (delalloc_lock)
5911                 mutex_lock(&inode->delalloc_mutex);
5912
5913         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5914
5915         /* Add our new extents and calculate the new rsv size. */
5916         spin_lock(&inode->lock);
5917         nr_extents = count_max_extents(num_bytes);
5918         btrfs_mod_outstanding_extents(inode, nr_extents);
5919         inode->csum_bytes += num_bytes;
5920         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5921         spin_unlock(&inode->lock);
5922
5923         ret = btrfs_inode_rsv_refill(inode, flush);
5924         if (unlikely(ret))
5925                 goto out_fail;
5926
5927         if (delalloc_lock)
5928                 mutex_unlock(&inode->delalloc_mutex);
5929         return 0;
5930
5931 out_fail:
5932         spin_lock(&inode->lock);
5933         nr_extents = count_max_extents(num_bytes);
5934         btrfs_mod_outstanding_extents(inode, -nr_extents);
5935         inode->csum_bytes -= num_bytes;
5936         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5937         spin_unlock(&inode->lock);
5938
5939         btrfs_inode_rsv_release(inode, true);
5940         if (delalloc_lock)
5941                 mutex_unlock(&inode->delalloc_mutex);
5942         return ret;
5943 }
5944
5945 /**
5946  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5947  * @inode: the inode to release the reservation for.
5948  * @num_bytes: the number of bytes we are releasing.
5949  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
5950  *
5951  * This will release the metadata reservation for an inode.  This can be called
5952  * once we complete IO for a given set of bytes to release their metadata
5953  * reservations, or on error for the same reason.
5954  */
5955 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
5956                                      bool qgroup_free)
5957 {
5958         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5959
5960         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5961         spin_lock(&inode->lock);
5962         inode->csum_bytes -= num_bytes;
5963         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5964         spin_unlock(&inode->lock);
5965
5966         if (btrfs_is_testing(fs_info))
5967                 return;
5968
5969         btrfs_inode_rsv_release(inode, qgroup_free);
5970 }
5971
5972 /**
5973  * btrfs_delalloc_release_extents - release our outstanding_extents
5974  * @inode: the inode to balance the reservation for.
5975  * @num_bytes: the number of bytes we originally reserved with
5976  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
5977  *
5978  * When we reserve space we increase outstanding_extents for the extents we may
5979  * add.  Once we've set the range as delalloc or created our ordered extents we
5980  * have outstanding_extents to track the real usage, so we use this to free our
5981  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
5982  * with btrfs_delalloc_reserve_metadata.
5983  */
5984 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
5985                                     bool qgroup_free)
5986 {
5987         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5988         unsigned num_extents;
5989
5990         spin_lock(&inode->lock);
5991         num_extents = count_max_extents(num_bytes);
5992         btrfs_mod_outstanding_extents(inode, -num_extents);
5993         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5994         spin_unlock(&inode->lock);
5995
5996         if (btrfs_is_testing(fs_info))
5997                 return;
5998
5999         btrfs_inode_rsv_release(inode, qgroup_free);
6000 }
6001
6002 /**
6003  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6004  * delalloc
6005  * @inode: inode we're writing to
6006  * @start: start range we are writing to
6007  * @len: how long the range we are writing to
6008  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6009  *            current reservation.
6010  *
6011  * This will do the following things
6012  *
6013  * o reserve space in data space info for num bytes
6014  *   and reserve precious corresponding qgroup space
6015  *   (Done in check_data_free_space)
6016  *
6017  * o reserve space for metadata space, based on the number of outstanding
6018  *   extents and how much csums will be needed
6019  *   also reserve metadata space in a per root over-reserve method.
6020  * o add to the inodes->delalloc_bytes
6021  * o add it to the fs_info's delalloc inodes list.
6022  *   (Above 3 all done in delalloc_reserve_metadata)
6023  *
6024  * Return 0 for success
6025  * Return <0 for error(-ENOSPC or -EQUOT)
6026  */
6027 int btrfs_delalloc_reserve_space(struct inode *inode,
6028                         struct extent_changeset **reserved, u64 start, u64 len)
6029 {
6030         int ret;
6031
6032         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6033         if (ret < 0)
6034                 return ret;
6035         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6036         if (ret < 0)
6037                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6038         return ret;
6039 }
6040
6041 /**
6042  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6043  * @inode: inode we're releasing space for
6044  * @start: start position of the space already reserved
6045  * @len: the len of the space already reserved
6046  * @release_bytes: the len of the space we consumed or didn't use
6047  *
6048  * This function will release the metadata space that was not used and will
6049  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6050  * list if there are no delalloc bytes left.
6051  * Also it will handle the qgroup reserved space.
6052  */
6053 void btrfs_delalloc_release_space(struct inode *inode,
6054                                   struct extent_changeset *reserved,
6055                                   u64 start, u64 len, bool qgroup_free)
6056 {
6057         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6058         btrfs_free_reserved_data_space(inode, reserved, start, len);
6059 }
6060
6061 static int update_block_group(struct btrfs_trans_handle *trans,
6062                               struct btrfs_fs_info *info, u64 bytenr,
6063                               u64 num_bytes, int alloc)
6064 {
6065         struct btrfs_block_group_cache *cache = NULL;
6066         u64 total = num_bytes;
6067         u64 old_val;
6068         u64 byte_in_group;
6069         int factor;
6070
6071         /* block accounting for super block */
6072         spin_lock(&info->delalloc_root_lock);
6073         old_val = btrfs_super_bytes_used(info->super_copy);
6074         if (alloc)
6075                 old_val += num_bytes;
6076         else
6077                 old_val -= num_bytes;
6078         btrfs_set_super_bytes_used(info->super_copy, old_val);
6079         spin_unlock(&info->delalloc_root_lock);
6080
6081         while (total) {
6082                 cache = btrfs_lookup_block_group(info, bytenr);
6083                 if (!cache)
6084                         return -ENOENT;
6085                 factor = btrfs_bg_type_to_factor(cache->flags);
6086
6087                 /*
6088                  * If this block group has free space cache written out, we
6089                  * need to make sure to load it if we are removing space.  This
6090                  * is because we need the unpinning stage to actually add the
6091                  * space back to the block group, otherwise we will leak space.
6092                  */
6093                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6094                         cache_block_group(cache, 1);
6095
6096                 byte_in_group = bytenr - cache->key.objectid;
6097                 WARN_ON(byte_in_group > cache->key.offset);
6098
6099                 spin_lock(&cache->space_info->lock);
6100                 spin_lock(&cache->lock);
6101
6102                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6103                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6104                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6105
6106                 old_val = btrfs_block_group_used(&cache->item);
6107                 num_bytes = min(total, cache->key.offset - byte_in_group);
6108                 if (alloc) {
6109                         old_val += num_bytes;
6110                         btrfs_set_block_group_used(&cache->item, old_val);
6111                         cache->reserved -= num_bytes;
6112                         cache->space_info->bytes_reserved -= num_bytes;
6113                         cache->space_info->bytes_used += num_bytes;
6114                         cache->space_info->disk_used += num_bytes * factor;
6115                         spin_unlock(&cache->lock);
6116                         spin_unlock(&cache->space_info->lock);
6117                 } else {
6118                         old_val -= num_bytes;
6119                         btrfs_set_block_group_used(&cache->item, old_val);
6120                         cache->pinned += num_bytes;
6121                         cache->space_info->bytes_pinned += num_bytes;
6122                         cache->space_info->bytes_used -= num_bytes;
6123                         cache->space_info->disk_used -= num_bytes * factor;
6124                         spin_unlock(&cache->lock);
6125                         spin_unlock(&cache->space_info->lock);
6126
6127                         trace_btrfs_space_reservation(info, "pinned",
6128                                                       cache->space_info->flags,
6129                                                       num_bytes, 1);
6130                         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6131                                            num_bytes,
6132                                            BTRFS_TOTAL_BYTES_PINNED_BATCH);
6133                         set_extent_dirty(info->pinned_extents,
6134                                          bytenr, bytenr + num_bytes - 1,
6135                                          GFP_NOFS | __GFP_NOFAIL);
6136                 }
6137
6138                 spin_lock(&trans->transaction->dirty_bgs_lock);
6139                 if (list_empty(&cache->dirty_list)) {
6140                         list_add_tail(&cache->dirty_list,
6141                                       &trans->transaction->dirty_bgs);
6142                         trans->transaction->num_dirty_bgs++;
6143                         btrfs_get_block_group(cache);
6144                 }
6145                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6146
6147                 /*
6148                  * No longer have used bytes in this block group, queue it for
6149                  * deletion. We do this after adding the block group to the
6150                  * dirty list to avoid races between cleaner kthread and space
6151                  * cache writeout.
6152                  */
6153                 if (!alloc && old_val == 0)
6154                         btrfs_mark_bg_unused(cache);
6155
6156                 btrfs_put_block_group(cache);
6157                 total -= num_bytes;
6158                 bytenr += num_bytes;
6159         }
6160         return 0;
6161 }
6162
6163 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6164 {
6165         struct btrfs_block_group_cache *cache;
6166         u64 bytenr;
6167
6168         spin_lock(&fs_info->block_group_cache_lock);
6169         bytenr = fs_info->first_logical_byte;
6170         spin_unlock(&fs_info->block_group_cache_lock);
6171
6172         if (bytenr < (u64)-1)
6173                 return bytenr;
6174
6175         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6176         if (!cache)
6177                 return 0;
6178
6179         bytenr = cache->key.objectid;
6180         btrfs_put_block_group(cache);
6181
6182         return bytenr;
6183 }
6184
6185 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6186                            struct btrfs_block_group_cache *cache,
6187                            u64 bytenr, u64 num_bytes, int reserved)
6188 {
6189         spin_lock(&cache->space_info->lock);
6190         spin_lock(&cache->lock);
6191         cache->pinned += num_bytes;
6192         cache->space_info->bytes_pinned += num_bytes;
6193         if (reserved) {
6194                 cache->reserved -= num_bytes;
6195                 cache->space_info->bytes_reserved -= num_bytes;
6196         }
6197         spin_unlock(&cache->lock);
6198         spin_unlock(&cache->space_info->lock);
6199
6200         trace_btrfs_space_reservation(fs_info, "pinned",
6201                                       cache->space_info->flags, num_bytes, 1);
6202         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6203                     num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6204         set_extent_dirty(fs_info->pinned_extents, bytenr,
6205                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6206         return 0;
6207 }
6208
6209 /*
6210  * this function must be called within transaction
6211  */
6212 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6213                      u64 bytenr, u64 num_bytes, int reserved)
6214 {
6215         struct btrfs_block_group_cache *cache;
6216
6217         cache = btrfs_lookup_block_group(fs_info, bytenr);
6218         BUG_ON(!cache); /* Logic error */
6219
6220         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6221
6222         btrfs_put_block_group(cache);
6223         return 0;
6224 }
6225
6226 /*
6227  * this function must be called within transaction
6228  */
6229 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6230                                     u64 bytenr, u64 num_bytes)
6231 {
6232         struct btrfs_block_group_cache *cache;
6233         int ret;
6234
6235         cache = btrfs_lookup_block_group(fs_info, bytenr);
6236         if (!cache)
6237                 return -EINVAL;
6238
6239         /*
6240          * pull in the free space cache (if any) so that our pin
6241          * removes the free space from the cache.  We have load_only set
6242          * to one because the slow code to read in the free extents does check
6243          * the pinned extents.
6244          */
6245         cache_block_group(cache, 1);
6246
6247         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6248
6249         /* remove us from the free space cache (if we're there at all) */
6250         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6251         btrfs_put_block_group(cache);
6252         return ret;
6253 }
6254
6255 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6256                                    u64 start, u64 num_bytes)
6257 {
6258         int ret;
6259         struct btrfs_block_group_cache *block_group;
6260         struct btrfs_caching_control *caching_ctl;
6261
6262         block_group = btrfs_lookup_block_group(fs_info, start);
6263         if (!block_group)
6264                 return -EINVAL;
6265
6266         cache_block_group(block_group, 0);
6267         caching_ctl = get_caching_control(block_group);
6268
6269         if (!caching_ctl) {
6270                 /* Logic error */
6271                 BUG_ON(!block_group_cache_done(block_group));
6272                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6273         } else {
6274                 mutex_lock(&caching_ctl->mutex);
6275
6276                 if (start >= caching_ctl->progress) {
6277                         ret = add_excluded_extent(fs_info, start, num_bytes);
6278                 } else if (start + num_bytes <= caching_ctl->progress) {
6279                         ret = btrfs_remove_free_space(block_group,
6280                                                       start, num_bytes);
6281                 } else {
6282                         num_bytes = caching_ctl->progress - start;
6283                         ret = btrfs_remove_free_space(block_group,
6284                                                       start, num_bytes);
6285                         if (ret)
6286                                 goto out_lock;
6287
6288                         num_bytes = (start + num_bytes) -
6289                                 caching_ctl->progress;
6290                         start = caching_ctl->progress;
6291                         ret = add_excluded_extent(fs_info, start, num_bytes);
6292                 }
6293 out_lock:
6294                 mutex_unlock(&caching_ctl->mutex);
6295                 put_caching_control(caching_ctl);
6296         }
6297         btrfs_put_block_group(block_group);
6298         return ret;
6299 }
6300
6301 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6302                                  struct extent_buffer *eb)
6303 {
6304         struct btrfs_file_extent_item *item;
6305         struct btrfs_key key;
6306         int found_type;
6307         int i;
6308         int ret = 0;
6309
6310         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6311                 return 0;
6312
6313         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6314                 btrfs_item_key_to_cpu(eb, &key, i);
6315                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6316                         continue;
6317                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6318                 found_type = btrfs_file_extent_type(eb, item);
6319                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6320                         continue;
6321                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6322                         continue;
6323                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6324                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6325                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
6326                 if (ret)
6327                         break;
6328         }
6329
6330         return ret;
6331 }
6332
6333 static void
6334 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6335 {
6336         atomic_inc(&bg->reservations);
6337 }
6338
6339 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6340                                         const u64 start)
6341 {
6342         struct btrfs_block_group_cache *bg;
6343
6344         bg = btrfs_lookup_block_group(fs_info, start);
6345         ASSERT(bg);
6346         if (atomic_dec_and_test(&bg->reservations))
6347                 wake_up_var(&bg->reservations);
6348         btrfs_put_block_group(bg);
6349 }
6350
6351 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6352 {
6353         struct btrfs_space_info *space_info = bg->space_info;
6354
6355         ASSERT(bg->ro);
6356
6357         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6358                 return;
6359
6360         /*
6361          * Our block group is read only but before we set it to read only,
6362          * some task might have had allocated an extent from it already, but it
6363          * has not yet created a respective ordered extent (and added it to a
6364          * root's list of ordered extents).
6365          * Therefore wait for any task currently allocating extents, since the
6366          * block group's reservations counter is incremented while a read lock
6367          * on the groups' semaphore is held and decremented after releasing
6368          * the read access on that semaphore and creating the ordered extent.
6369          */
6370         down_write(&space_info->groups_sem);
6371         up_write(&space_info->groups_sem);
6372
6373         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
6374 }
6375
6376 /**
6377  * btrfs_add_reserved_bytes - update the block_group and space info counters
6378  * @cache:      The cache we are manipulating
6379  * @ram_bytes:  The number of bytes of file content, and will be same to
6380  *              @num_bytes except for the compress path.
6381  * @num_bytes:  The number of bytes in question
6382  * @delalloc:   The blocks are allocated for the delalloc write
6383  *
6384  * This is called by the allocator when it reserves space. If this is a
6385  * reservation and the block group has become read only we cannot make the
6386  * reservation and return -EAGAIN, otherwise this function always succeeds.
6387  */
6388 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6389                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6390 {
6391         struct btrfs_space_info *space_info = cache->space_info;
6392         int ret = 0;
6393
6394         spin_lock(&space_info->lock);
6395         spin_lock(&cache->lock);
6396         if (cache->ro) {
6397                 ret = -EAGAIN;
6398         } else {
6399                 cache->reserved += num_bytes;
6400                 space_info->bytes_reserved += num_bytes;
6401
6402                 trace_btrfs_space_reservation(cache->fs_info,
6403                                 "space_info", space_info->flags,
6404                                 ram_bytes, 0);
6405                 space_info->bytes_may_use -= ram_bytes;
6406                 if (delalloc)
6407                         cache->delalloc_bytes += num_bytes;
6408         }
6409         spin_unlock(&cache->lock);
6410         spin_unlock(&space_info->lock);
6411         return ret;
6412 }
6413
6414 /**
6415  * btrfs_free_reserved_bytes - update the block_group and space info counters
6416  * @cache:      The cache we are manipulating
6417  * @num_bytes:  The number of bytes in question
6418  * @delalloc:   The blocks are allocated for the delalloc write
6419  *
6420  * This is called by somebody who is freeing space that was never actually used
6421  * on disk.  For example if you reserve some space for a new leaf in transaction
6422  * A and before transaction A commits you free that leaf, you call this with
6423  * reserve set to 0 in order to clear the reservation.
6424  */
6425
6426 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6427                                      u64 num_bytes, int delalloc)
6428 {
6429         struct btrfs_space_info *space_info = cache->space_info;
6430         int ret = 0;
6431
6432         spin_lock(&space_info->lock);
6433         spin_lock(&cache->lock);
6434         if (cache->ro)
6435                 space_info->bytes_readonly += num_bytes;
6436         cache->reserved -= num_bytes;
6437         space_info->bytes_reserved -= num_bytes;
6438         space_info->max_extent_size = 0;
6439
6440         if (delalloc)
6441                 cache->delalloc_bytes -= num_bytes;
6442         spin_unlock(&cache->lock);
6443         spin_unlock(&space_info->lock);
6444         return ret;
6445 }
6446 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6447 {
6448         struct btrfs_caching_control *next;
6449         struct btrfs_caching_control *caching_ctl;
6450         struct btrfs_block_group_cache *cache;
6451
6452         down_write(&fs_info->commit_root_sem);
6453
6454         list_for_each_entry_safe(caching_ctl, next,
6455                                  &fs_info->caching_block_groups, list) {
6456                 cache = caching_ctl->block_group;
6457                 if (block_group_cache_done(cache)) {
6458                         cache->last_byte_to_unpin = (u64)-1;
6459                         list_del_init(&caching_ctl->list);
6460                         put_caching_control(caching_ctl);
6461                 } else {
6462                         cache->last_byte_to_unpin = caching_ctl->progress;
6463                 }
6464         }
6465
6466         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6467                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6468         else
6469                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6470
6471         up_write(&fs_info->commit_root_sem);
6472
6473         update_global_block_rsv(fs_info);
6474 }
6475
6476 /*
6477  * Returns the free cluster for the given space info and sets empty_cluster to
6478  * what it should be based on the mount options.
6479  */
6480 static struct btrfs_free_cluster *
6481 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6482                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6483 {
6484         struct btrfs_free_cluster *ret = NULL;
6485
6486         *empty_cluster = 0;
6487         if (btrfs_mixed_space_info(space_info))
6488                 return ret;
6489
6490         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6491                 ret = &fs_info->meta_alloc_cluster;
6492                 if (btrfs_test_opt(fs_info, SSD))
6493                         *empty_cluster = SZ_2M;
6494                 else
6495                         *empty_cluster = SZ_64K;
6496         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6497                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6498                 *empty_cluster = SZ_2M;
6499                 ret = &fs_info->data_alloc_cluster;
6500         }
6501
6502         return ret;
6503 }
6504
6505 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6506                               u64 start, u64 end,
6507                               const bool return_free_space)
6508 {
6509         struct btrfs_block_group_cache *cache = NULL;
6510         struct btrfs_space_info *space_info;
6511         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6512         struct btrfs_free_cluster *cluster = NULL;
6513         u64 len;
6514         u64 total_unpinned = 0;
6515         u64 empty_cluster = 0;
6516         bool readonly;
6517
6518         while (start <= end) {
6519                 readonly = false;
6520                 if (!cache ||
6521                     start >= cache->key.objectid + cache->key.offset) {
6522                         if (cache)
6523                                 btrfs_put_block_group(cache);
6524                         total_unpinned = 0;
6525                         cache = btrfs_lookup_block_group(fs_info, start);
6526                         BUG_ON(!cache); /* Logic error */
6527
6528                         cluster = fetch_cluster_info(fs_info,
6529                                                      cache->space_info,
6530                                                      &empty_cluster);
6531                         empty_cluster <<= 1;
6532                 }
6533
6534                 len = cache->key.objectid + cache->key.offset - start;
6535                 len = min(len, end + 1 - start);
6536
6537                 if (start < cache->last_byte_to_unpin) {
6538                         len = min(len, cache->last_byte_to_unpin - start);
6539                         if (return_free_space)
6540                                 btrfs_add_free_space(cache, start, len);
6541                 }
6542
6543                 start += len;
6544                 total_unpinned += len;
6545                 space_info = cache->space_info;
6546
6547                 /*
6548                  * If this space cluster has been marked as fragmented and we've
6549                  * unpinned enough in this block group to potentially allow a
6550                  * cluster to be created inside of it go ahead and clear the
6551                  * fragmented check.
6552                  */
6553                 if (cluster && cluster->fragmented &&
6554                     total_unpinned > empty_cluster) {
6555                         spin_lock(&cluster->lock);
6556                         cluster->fragmented = 0;
6557                         spin_unlock(&cluster->lock);
6558                 }
6559
6560                 spin_lock(&space_info->lock);
6561                 spin_lock(&cache->lock);
6562                 cache->pinned -= len;
6563                 space_info->bytes_pinned -= len;
6564
6565                 trace_btrfs_space_reservation(fs_info, "pinned",
6566                                               space_info->flags, len, 0);
6567                 space_info->max_extent_size = 0;
6568                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
6569                             -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6570                 if (cache->ro) {
6571                         space_info->bytes_readonly += len;
6572                         readonly = true;
6573                 }
6574                 spin_unlock(&cache->lock);
6575                 if (!readonly && return_free_space &&
6576                     global_rsv->space_info == space_info) {
6577                         u64 to_add = len;
6578
6579                         spin_lock(&global_rsv->lock);
6580                         if (!global_rsv->full) {
6581                                 to_add = min(len, global_rsv->size -
6582                                              global_rsv->reserved);
6583                                 global_rsv->reserved += to_add;
6584                                 space_info->bytes_may_use += to_add;
6585                                 if (global_rsv->reserved >= global_rsv->size)
6586                                         global_rsv->full = 1;
6587                                 trace_btrfs_space_reservation(fs_info,
6588                                                               "space_info",
6589                                                               space_info->flags,
6590                                                               to_add, 1);
6591                                 len -= to_add;
6592                         }
6593                         spin_unlock(&global_rsv->lock);
6594                         /* Add to any tickets we may have */
6595                         if (len)
6596                                 space_info_add_new_bytes(fs_info, space_info,
6597                                                          len);
6598                 }
6599                 spin_unlock(&space_info->lock);
6600         }
6601
6602         if (cache)
6603                 btrfs_put_block_group(cache);
6604         return 0;
6605 }
6606
6607 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6608 {
6609         struct btrfs_fs_info *fs_info = trans->fs_info;
6610         struct btrfs_block_group_cache *block_group, *tmp;
6611         struct list_head *deleted_bgs;
6612         struct extent_io_tree *unpin;
6613         u64 start;
6614         u64 end;
6615         int ret;
6616
6617         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6618                 unpin = &fs_info->freed_extents[1];
6619         else
6620                 unpin = &fs_info->freed_extents[0];
6621
6622         while (!trans->aborted) {
6623                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6624                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6625                                             EXTENT_DIRTY, NULL);
6626                 if (ret) {
6627                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6628                         break;
6629                 }
6630
6631                 if (btrfs_test_opt(fs_info, DISCARD))
6632                         ret = btrfs_discard_extent(fs_info, start,
6633                                                    end + 1 - start, NULL);
6634
6635                 clear_extent_dirty(unpin, start, end);
6636                 unpin_extent_range(fs_info, start, end, true);
6637                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6638                 cond_resched();
6639         }
6640
6641         /*
6642          * Transaction is finished.  We don't need the lock anymore.  We
6643          * do need to clean up the block groups in case of a transaction
6644          * abort.
6645          */
6646         deleted_bgs = &trans->transaction->deleted_bgs;
6647         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6648                 u64 trimmed = 0;
6649
6650                 ret = -EROFS;
6651                 if (!trans->aborted)
6652                         ret = btrfs_discard_extent(fs_info,
6653                                                    block_group->key.objectid,
6654                                                    block_group->key.offset,
6655                                                    &trimmed);
6656
6657                 list_del_init(&block_group->bg_list);
6658                 btrfs_put_block_group_trimming(block_group);
6659                 btrfs_put_block_group(block_group);
6660
6661                 if (ret) {
6662                         const char *errstr = btrfs_decode_error(ret);
6663                         btrfs_warn(fs_info,
6664                            "discard failed while removing blockgroup: errno=%d %s",
6665                                    ret, errstr);
6666                 }
6667         }
6668
6669         return 0;
6670 }
6671
6672 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6673                                struct btrfs_delayed_ref_node *node, u64 parent,
6674                                u64 root_objectid, u64 owner_objectid,
6675                                u64 owner_offset, int refs_to_drop,
6676                                struct btrfs_delayed_extent_op *extent_op)
6677 {
6678         struct btrfs_fs_info *info = trans->fs_info;
6679         struct btrfs_key key;
6680         struct btrfs_path *path;
6681         struct btrfs_root *extent_root = info->extent_root;
6682         struct extent_buffer *leaf;
6683         struct btrfs_extent_item *ei;
6684         struct btrfs_extent_inline_ref *iref;
6685         int ret;
6686         int is_data;
6687         int extent_slot = 0;
6688         int found_extent = 0;
6689         int num_to_del = 1;
6690         u32 item_size;
6691         u64 refs;
6692         u64 bytenr = node->bytenr;
6693         u64 num_bytes = node->num_bytes;
6694         int last_ref = 0;
6695         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6696
6697         path = btrfs_alloc_path();
6698         if (!path)
6699                 return -ENOMEM;
6700
6701         path->reada = READA_FORWARD;
6702         path->leave_spinning = 1;
6703
6704         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6705         BUG_ON(!is_data && refs_to_drop != 1);
6706
6707         if (is_data)
6708                 skinny_metadata = false;
6709
6710         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
6711                                     parent, root_objectid, owner_objectid,
6712                                     owner_offset);
6713         if (ret == 0) {
6714                 extent_slot = path->slots[0];
6715                 while (extent_slot >= 0) {
6716                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6717                                               extent_slot);
6718                         if (key.objectid != bytenr)
6719                                 break;
6720                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6721                             key.offset == num_bytes) {
6722                                 found_extent = 1;
6723                                 break;
6724                         }
6725                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6726                             key.offset == owner_objectid) {
6727                                 found_extent = 1;
6728                                 break;
6729                         }
6730                         if (path->slots[0] - extent_slot > 5)
6731                                 break;
6732                         extent_slot--;
6733                 }
6734
6735                 if (!found_extent) {
6736                         BUG_ON(iref);
6737                         ret = remove_extent_backref(trans, path, NULL,
6738                                                     refs_to_drop,
6739                                                     is_data, &last_ref);
6740                         if (ret) {
6741                                 btrfs_abort_transaction(trans, ret);
6742                                 goto out;
6743                         }
6744                         btrfs_release_path(path);
6745                         path->leave_spinning = 1;
6746
6747                         key.objectid = bytenr;
6748                         key.type = BTRFS_EXTENT_ITEM_KEY;
6749                         key.offset = num_bytes;
6750
6751                         if (!is_data && skinny_metadata) {
6752                                 key.type = BTRFS_METADATA_ITEM_KEY;
6753                                 key.offset = owner_objectid;
6754                         }
6755
6756                         ret = btrfs_search_slot(trans, extent_root,
6757                                                 &key, path, -1, 1);
6758                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6759                                 /*
6760                                  * Couldn't find our skinny metadata item,
6761                                  * see if we have ye olde extent item.
6762                                  */
6763                                 path->slots[0]--;
6764                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6765                                                       path->slots[0]);
6766                                 if (key.objectid == bytenr &&
6767                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6768                                     key.offset == num_bytes)
6769                                         ret = 0;
6770                         }
6771
6772                         if (ret > 0 && skinny_metadata) {
6773                                 skinny_metadata = false;
6774                                 key.objectid = bytenr;
6775                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6776                                 key.offset = num_bytes;
6777                                 btrfs_release_path(path);
6778                                 ret = btrfs_search_slot(trans, extent_root,
6779                                                         &key, path, -1, 1);
6780                         }
6781
6782                         if (ret) {
6783                                 btrfs_err(info,
6784                                           "umm, got %d back from search, was looking for %llu",
6785                                           ret, bytenr);
6786                                 if (ret > 0)
6787                                         btrfs_print_leaf(path->nodes[0]);
6788                         }
6789                         if (ret < 0) {
6790                                 btrfs_abort_transaction(trans, ret);
6791                                 goto out;
6792                         }
6793                         extent_slot = path->slots[0];
6794                 }
6795         } else if (WARN_ON(ret == -ENOENT)) {
6796                 btrfs_print_leaf(path->nodes[0]);
6797                 btrfs_err(info,
6798                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6799                         bytenr, parent, root_objectid, owner_objectid,
6800                         owner_offset);
6801                 btrfs_abort_transaction(trans, ret);
6802                 goto out;
6803         } else {
6804                 btrfs_abort_transaction(trans, ret);
6805                 goto out;
6806         }
6807
6808         leaf = path->nodes[0];
6809         item_size = btrfs_item_size_nr(leaf, extent_slot);
6810         if (unlikely(item_size < sizeof(*ei))) {
6811                 ret = -EINVAL;
6812                 btrfs_print_v0_err(info);
6813                 btrfs_abort_transaction(trans, ret);
6814                 goto out;
6815         }
6816         ei = btrfs_item_ptr(leaf, extent_slot,
6817                             struct btrfs_extent_item);
6818         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6819             key.type == BTRFS_EXTENT_ITEM_KEY) {
6820                 struct btrfs_tree_block_info *bi;
6821                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6822                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6823                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6824         }
6825
6826         refs = btrfs_extent_refs(leaf, ei);
6827         if (refs < refs_to_drop) {
6828                 btrfs_err(info,
6829                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
6830                           refs_to_drop, refs, bytenr);
6831                 ret = -EINVAL;
6832                 btrfs_abort_transaction(trans, ret);
6833                 goto out;
6834         }
6835         refs -= refs_to_drop;
6836
6837         if (refs > 0) {
6838                 if (extent_op)
6839                         __run_delayed_extent_op(extent_op, leaf, ei);
6840                 /*
6841                  * In the case of inline back ref, reference count will
6842                  * be updated by remove_extent_backref
6843                  */
6844                 if (iref) {
6845                         BUG_ON(!found_extent);
6846                 } else {
6847                         btrfs_set_extent_refs(leaf, ei, refs);
6848                         btrfs_mark_buffer_dirty(leaf);
6849                 }
6850                 if (found_extent) {
6851                         ret = remove_extent_backref(trans, path, iref,
6852                                                     refs_to_drop, is_data,
6853                                                     &last_ref);
6854                         if (ret) {
6855                                 btrfs_abort_transaction(trans, ret);
6856                                 goto out;
6857                         }
6858                 }
6859         } else {
6860                 if (found_extent) {
6861                         BUG_ON(is_data && refs_to_drop !=
6862                                extent_data_ref_count(path, iref));
6863                         if (iref) {
6864                                 BUG_ON(path->slots[0] != extent_slot);
6865                         } else {
6866                                 BUG_ON(path->slots[0] != extent_slot + 1);
6867                                 path->slots[0] = extent_slot;
6868                                 num_to_del = 2;
6869                         }
6870                 }
6871
6872                 last_ref = 1;
6873                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6874                                       num_to_del);
6875                 if (ret) {
6876                         btrfs_abort_transaction(trans, ret);
6877                         goto out;
6878                 }
6879                 btrfs_release_path(path);
6880
6881                 if (is_data) {
6882                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
6883                         if (ret) {
6884                                 btrfs_abort_transaction(trans, ret);
6885                                 goto out;
6886                         }
6887                 }
6888
6889                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
6890                 if (ret) {
6891                         btrfs_abort_transaction(trans, ret);
6892                         goto out;
6893                 }
6894
6895                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
6896                 if (ret) {
6897                         btrfs_abort_transaction(trans, ret);
6898                         goto out;
6899                 }
6900         }
6901         btrfs_release_path(path);
6902
6903 out:
6904         btrfs_free_path(path);
6905         return ret;
6906 }
6907
6908 /*
6909  * when we free an block, it is possible (and likely) that we free the last
6910  * delayed ref for that extent as well.  This searches the delayed ref tree for
6911  * a given extent, and if there are no other delayed refs to be processed, it
6912  * removes it from the tree.
6913  */
6914 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6915                                       u64 bytenr)
6916 {
6917         struct btrfs_delayed_ref_head *head;
6918         struct btrfs_delayed_ref_root *delayed_refs;
6919         int ret = 0;
6920
6921         delayed_refs = &trans->transaction->delayed_refs;
6922         spin_lock(&delayed_refs->lock);
6923         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
6924         if (!head)
6925                 goto out_delayed_unlock;
6926
6927         spin_lock(&head->lock);
6928         if (!RB_EMPTY_ROOT(&head->ref_tree))
6929                 goto out;
6930
6931         if (head->extent_op) {
6932                 if (!head->must_insert_reserved)
6933                         goto out;
6934                 btrfs_free_delayed_extent_op(head->extent_op);
6935                 head->extent_op = NULL;
6936         }
6937
6938         /*
6939          * waiting for the lock here would deadlock.  If someone else has it
6940          * locked they are already in the process of dropping it anyway
6941          */
6942         if (!mutex_trylock(&head->mutex))
6943                 goto out;
6944
6945         /*
6946          * at this point we have a head with no other entries.  Go
6947          * ahead and process it.
6948          */
6949         rb_erase(&head->href_node, &delayed_refs->href_root);
6950         RB_CLEAR_NODE(&head->href_node);
6951         atomic_dec(&delayed_refs->num_entries);
6952
6953         /*
6954          * we don't take a ref on the node because we're removing it from the
6955          * tree, so we just steal the ref the tree was holding.
6956          */
6957         delayed_refs->num_heads--;
6958         if (head->processing == 0)
6959                 delayed_refs->num_heads_ready--;
6960         head->processing = 0;
6961         spin_unlock(&head->lock);
6962         spin_unlock(&delayed_refs->lock);
6963
6964         BUG_ON(head->extent_op);
6965         if (head->must_insert_reserved)
6966                 ret = 1;
6967
6968         mutex_unlock(&head->mutex);
6969         btrfs_put_delayed_ref_head(head);
6970         return ret;
6971 out:
6972         spin_unlock(&head->lock);
6973
6974 out_delayed_unlock:
6975         spin_unlock(&delayed_refs->lock);
6976         return 0;
6977 }
6978
6979 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6980                            struct btrfs_root *root,
6981                            struct extent_buffer *buf,
6982                            u64 parent, int last_ref)
6983 {
6984         struct btrfs_fs_info *fs_info = root->fs_info;
6985         int pin = 1;
6986         int ret;
6987
6988         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6989                 int old_ref_mod, new_ref_mod;
6990
6991                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
6992                                    root->root_key.objectid,
6993                                    btrfs_header_level(buf), 0,
6994                                    BTRFS_DROP_DELAYED_REF);
6995                 ret = btrfs_add_delayed_tree_ref(trans, buf->start,
6996                                                  buf->len, parent,
6997                                                  root->root_key.objectid,
6998                                                  btrfs_header_level(buf),
6999                                                  BTRFS_DROP_DELAYED_REF, NULL,
7000                                                  &old_ref_mod, &new_ref_mod);
7001                 BUG_ON(ret); /* -ENOMEM */
7002                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7003         }
7004
7005         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7006                 struct btrfs_block_group_cache *cache;
7007
7008                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7009                         ret = check_ref_cleanup(trans, buf->start);
7010                         if (!ret)
7011                                 goto out;
7012                 }
7013
7014                 pin = 0;
7015                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7016
7017                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7018                         pin_down_extent(fs_info, cache, buf->start,
7019                                         buf->len, 1);
7020                         btrfs_put_block_group(cache);
7021                         goto out;
7022                 }
7023
7024                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7025
7026                 btrfs_add_free_space(cache, buf->start, buf->len);
7027                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7028                 btrfs_put_block_group(cache);
7029                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7030         }
7031 out:
7032         if (pin)
7033                 add_pinned_bytes(fs_info, buf->len, true,
7034                                  root->root_key.objectid);
7035
7036         if (last_ref) {
7037                 /*
7038                  * Deleting the buffer, clear the corrupt flag since it doesn't
7039                  * matter anymore.
7040                  */
7041                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7042         }
7043 }
7044
7045 /* Can return -ENOMEM */
7046 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7047                       struct btrfs_root *root,
7048                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7049                       u64 owner, u64 offset)
7050 {
7051         struct btrfs_fs_info *fs_info = root->fs_info;
7052         int old_ref_mod, new_ref_mod;
7053         int ret;
7054
7055         if (btrfs_is_testing(fs_info))
7056                 return 0;
7057
7058         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7059                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7060                                    root_objectid, owner, offset,
7061                                    BTRFS_DROP_DELAYED_REF);
7062
7063         /*
7064          * tree log blocks never actually go into the extent allocation
7065          * tree, just update pinning info and exit early.
7066          */
7067         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7068                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7069                 /* unlocks the pinned mutex */
7070                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7071                 old_ref_mod = new_ref_mod = 0;
7072                 ret = 0;
7073         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7074                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
7075                                                  num_bytes, parent,
7076                                                  root_objectid, (int)owner,
7077                                                  BTRFS_DROP_DELAYED_REF, NULL,
7078                                                  &old_ref_mod, &new_ref_mod);
7079         } else {
7080                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
7081                                                  num_bytes, parent,
7082                                                  root_objectid, owner, offset,
7083                                                  0, BTRFS_DROP_DELAYED_REF,
7084                                                  &old_ref_mod, &new_ref_mod);
7085         }
7086
7087         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0) {
7088                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
7089
7090                 add_pinned_bytes(fs_info, num_bytes, metadata, root_objectid);
7091         }
7092
7093         return ret;
7094 }
7095
7096 /*
7097  * when we wait for progress in the block group caching, its because
7098  * our allocation attempt failed at least once.  So, we must sleep
7099  * and let some progress happen before we try again.
7100  *
7101  * This function will sleep at least once waiting for new free space to
7102  * show up, and then it will check the block group free space numbers
7103  * for our min num_bytes.  Another option is to have it go ahead
7104  * and look in the rbtree for a free extent of a given size, but this
7105  * is a good start.
7106  *
7107  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7108  * any of the information in this block group.
7109  */
7110 static noinline void
7111 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7112                                 u64 num_bytes)
7113 {
7114         struct btrfs_caching_control *caching_ctl;
7115
7116         caching_ctl = get_caching_control(cache);
7117         if (!caching_ctl)
7118                 return;
7119
7120         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7121                    (cache->free_space_ctl->free_space >= num_bytes));
7122
7123         put_caching_control(caching_ctl);
7124 }
7125
7126 static noinline int
7127 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7128 {
7129         struct btrfs_caching_control *caching_ctl;
7130         int ret = 0;
7131
7132         caching_ctl = get_caching_control(cache);
7133         if (!caching_ctl)
7134                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7135
7136         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7137         if (cache->cached == BTRFS_CACHE_ERROR)
7138                 ret = -EIO;
7139         put_caching_control(caching_ctl);
7140         return ret;
7141 }
7142
7143 enum btrfs_loop_type {
7144         LOOP_CACHING_NOWAIT = 0,
7145         LOOP_CACHING_WAIT = 1,
7146         LOOP_ALLOC_CHUNK = 2,
7147         LOOP_NO_EMPTY_SIZE = 3,
7148 };
7149
7150 static inline void
7151 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7152                        int delalloc)
7153 {
7154         if (delalloc)
7155                 down_read(&cache->data_rwsem);
7156 }
7157
7158 static inline void
7159 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7160                        int delalloc)
7161 {
7162         btrfs_get_block_group(cache);
7163         if (delalloc)
7164                 down_read(&cache->data_rwsem);
7165 }
7166
7167 static struct btrfs_block_group_cache *
7168 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7169                    struct btrfs_free_cluster *cluster,
7170                    int delalloc)
7171 {
7172         struct btrfs_block_group_cache *used_bg = NULL;
7173
7174         spin_lock(&cluster->refill_lock);
7175         while (1) {
7176                 used_bg = cluster->block_group;
7177                 if (!used_bg)
7178                         return NULL;
7179
7180                 if (used_bg == block_group)
7181                         return used_bg;
7182
7183                 btrfs_get_block_group(used_bg);
7184
7185                 if (!delalloc)
7186                         return used_bg;
7187
7188                 if (down_read_trylock(&used_bg->data_rwsem))
7189                         return used_bg;
7190
7191                 spin_unlock(&cluster->refill_lock);
7192
7193                 /* We should only have one-level nested. */
7194                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7195
7196                 spin_lock(&cluster->refill_lock);
7197                 if (used_bg == cluster->block_group)
7198                         return used_bg;
7199
7200                 up_read(&used_bg->data_rwsem);
7201                 btrfs_put_block_group(used_bg);
7202         }
7203 }
7204
7205 static inline void
7206 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7207                          int delalloc)
7208 {
7209         if (delalloc)
7210                 up_read(&cache->data_rwsem);
7211         btrfs_put_block_group(cache);
7212 }
7213
7214 /*
7215  * walks the btree of allocated extents and find a hole of a given size.
7216  * The key ins is changed to record the hole:
7217  * ins->objectid == start position
7218  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7219  * ins->offset == the size of the hole.
7220  * Any available blocks before search_start are skipped.
7221  *
7222  * If there is no suitable free space, we will record the max size of
7223  * the free space extent currently.
7224  */
7225 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7226                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7227                                 u64 hint_byte, struct btrfs_key *ins,
7228                                 u64 flags, int delalloc)
7229 {
7230         int ret = 0;
7231         struct btrfs_root *root = fs_info->extent_root;
7232         struct btrfs_free_cluster *last_ptr = NULL;
7233         struct btrfs_block_group_cache *block_group = NULL;
7234         u64 search_start = 0;
7235         u64 max_extent_size = 0;
7236         u64 max_free_space = 0;
7237         u64 empty_cluster = 0;
7238         struct btrfs_space_info *space_info;
7239         int loop = 0;
7240         int index = btrfs_bg_flags_to_raid_index(flags);
7241         bool failed_cluster_refill = false;
7242         bool failed_alloc = false;
7243         bool use_cluster = true;
7244         bool have_caching_bg = false;
7245         bool orig_have_caching_bg = false;
7246         bool full_search = false;
7247
7248         WARN_ON(num_bytes < fs_info->sectorsize);
7249         ins->type = BTRFS_EXTENT_ITEM_KEY;
7250         ins->objectid = 0;
7251         ins->offset = 0;
7252
7253         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7254
7255         space_info = __find_space_info(fs_info, flags);
7256         if (!space_info) {
7257                 btrfs_err(fs_info, "No space info for %llu", flags);
7258                 return -ENOSPC;
7259         }
7260
7261         /*
7262          * If our free space is heavily fragmented we may not be able to make
7263          * big contiguous allocations, so instead of doing the expensive search
7264          * for free space, simply return ENOSPC with our max_extent_size so we
7265          * can go ahead and search for a more manageable chunk.
7266          *
7267          * If our max_extent_size is large enough for our allocation simply
7268          * disable clustering since we will likely not be able to find enough
7269          * space to create a cluster and induce latency trying.
7270          */
7271         if (unlikely(space_info->max_extent_size)) {
7272                 spin_lock(&space_info->lock);
7273                 if (space_info->max_extent_size &&
7274                     num_bytes > space_info->max_extent_size) {
7275                         ins->offset = space_info->max_extent_size;
7276                         spin_unlock(&space_info->lock);
7277                         return -ENOSPC;
7278                 } else if (space_info->max_extent_size) {
7279                         use_cluster = false;
7280                 }
7281                 spin_unlock(&space_info->lock);
7282         }
7283
7284         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7285         if (last_ptr) {
7286                 spin_lock(&last_ptr->lock);
7287                 if (last_ptr->block_group)
7288                         hint_byte = last_ptr->window_start;
7289                 if (last_ptr->fragmented) {
7290                         /*
7291                          * We still set window_start so we can keep track of the
7292                          * last place we found an allocation to try and save
7293                          * some time.
7294                          */
7295                         hint_byte = last_ptr->window_start;
7296                         use_cluster = false;
7297                 }
7298                 spin_unlock(&last_ptr->lock);
7299         }
7300
7301         search_start = max(search_start, first_logical_byte(fs_info, 0));
7302         search_start = max(search_start, hint_byte);
7303         if (search_start == hint_byte) {
7304                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7305                 /*
7306                  * we don't want to use the block group if it doesn't match our
7307                  * allocation bits, or if its not cached.
7308                  *
7309                  * However if we are re-searching with an ideal block group
7310                  * picked out then we don't care that the block group is cached.
7311                  */
7312                 if (block_group && block_group_bits(block_group, flags) &&
7313                     block_group->cached != BTRFS_CACHE_NO) {
7314                         down_read(&space_info->groups_sem);
7315                         if (list_empty(&block_group->list) ||
7316                             block_group->ro) {
7317                                 /*
7318                                  * someone is removing this block group,
7319                                  * we can't jump into the have_block_group
7320                                  * target because our list pointers are not
7321                                  * valid
7322                                  */
7323                                 btrfs_put_block_group(block_group);
7324                                 up_read(&space_info->groups_sem);
7325                         } else {
7326                                 index = btrfs_bg_flags_to_raid_index(
7327                                                 block_group->flags);
7328                                 btrfs_lock_block_group(block_group, delalloc);
7329                                 goto have_block_group;
7330                         }
7331                 } else if (block_group) {
7332                         btrfs_put_block_group(block_group);
7333                 }
7334         }
7335 search:
7336         have_caching_bg = false;
7337         if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
7338                 full_search = true;
7339         down_read(&space_info->groups_sem);
7340         list_for_each_entry(block_group, &space_info->block_groups[index],
7341                             list) {
7342                 u64 offset;
7343                 int cached;
7344
7345                 /* If the block group is read-only, we can skip it entirely. */
7346                 if (unlikely(block_group->ro))
7347                         continue;
7348
7349                 btrfs_grab_block_group(block_group, delalloc);
7350                 search_start = block_group->key.objectid;
7351
7352                 /*
7353                  * this can happen if we end up cycling through all the
7354                  * raid types, but we want to make sure we only allocate
7355                  * for the proper type.
7356                  */
7357                 if (!block_group_bits(block_group, flags)) {
7358                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
7359                                 BTRFS_BLOCK_GROUP_RAID1 |
7360                                 BTRFS_BLOCK_GROUP_RAID5 |
7361                                 BTRFS_BLOCK_GROUP_RAID6 |
7362                                 BTRFS_BLOCK_GROUP_RAID10;
7363
7364                         /*
7365                          * if they asked for extra copies and this block group
7366                          * doesn't provide them, bail.  This does allow us to
7367                          * fill raid0 from raid1.
7368                          */
7369                         if ((flags & extra) && !(block_group->flags & extra))
7370                                 goto loop;
7371                 }
7372
7373 have_block_group:
7374                 cached = block_group_cache_done(block_group);
7375                 if (unlikely(!cached)) {
7376                         have_caching_bg = true;
7377                         ret = cache_block_group(block_group, 0);
7378                         BUG_ON(ret < 0);
7379                         ret = 0;
7380                 }
7381
7382                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7383                         goto loop;
7384
7385                 /*
7386                  * Ok we want to try and use the cluster allocator, so
7387                  * lets look there
7388                  */
7389                 if (last_ptr && use_cluster) {
7390                         struct btrfs_block_group_cache *used_block_group;
7391                         unsigned long aligned_cluster;
7392                         /*
7393                          * the refill lock keeps out other
7394                          * people trying to start a new cluster
7395                          */
7396                         used_block_group = btrfs_lock_cluster(block_group,
7397                                                               last_ptr,
7398                                                               delalloc);
7399                         if (!used_block_group)
7400                                 goto refill_cluster;
7401
7402                         if (used_block_group != block_group &&
7403                             (used_block_group->ro ||
7404                              !block_group_bits(used_block_group, flags)))
7405                                 goto release_cluster;
7406
7407                         offset = btrfs_alloc_from_cluster(used_block_group,
7408                                                 last_ptr,
7409                                                 num_bytes,
7410                                                 used_block_group->key.objectid,
7411                                                 &max_extent_size);
7412                         if (offset) {
7413                                 /* we have a block, we're done */
7414                                 spin_unlock(&last_ptr->refill_lock);
7415                                 trace_btrfs_reserve_extent_cluster(
7416                                                 used_block_group,
7417                                                 search_start, num_bytes);
7418                                 if (used_block_group != block_group) {
7419                                         btrfs_release_block_group(block_group,
7420                                                                   delalloc);
7421                                         block_group = used_block_group;
7422                                 }
7423                                 goto checks;
7424                         }
7425
7426                         WARN_ON(last_ptr->block_group != used_block_group);
7427 release_cluster:
7428                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7429                          * set up a new clusters, so lets just skip it
7430                          * and let the allocator find whatever block
7431                          * it can find.  If we reach this point, we
7432                          * will have tried the cluster allocator
7433                          * plenty of times and not have found
7434                          * anything, so we are likely way too
7435                          * fragmented for the clustering stuff to find
7436                          * anything.
7437                          *
7438                          * However, if the cluster is taken from the
7439                          * current block group, release the cluster
7440                          * first, so that we stand a better chance of
7441                          * succeeding in the unclustered
7442                          * allocation.  */
7443                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7444                             used_block_group != block_group) {
7445                                 spin_unlock(&last_ptr->refill_lock);
7446                                 btrfs_release_block_group(used_block_group,
7447                                                           delalloc);
7448                                 goto unclustered_alloc;
7449                         }
7450
7451                         /*
7452                          * this cluster didn't work out, free it and
7453                          * start over
7454                          */
7455                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7456
7457                         if (used_block_group != block_group)
7458                                 btrfs_release_block_group(used_block_group,
7459                                                           delalloc);
7460 refill_cluster:
7461                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7462                                 spin_unlock(&last_ptr->refill_lock);
7463                                 goto unclustered_alloc;
7464                         }
7465
7466                         aligned_cluster = max_t(unsigned long,
7467                                                 empty_cluster + empty_size,
7468                                               block_group->full_stripe_len);
7469
7470                         /* allocate a cluster in this block group */
7471                         ret = btrfs_find_space_cluster(fs_info, block_group,
7472                                                        last_ptr, search_start,
7473                                                        num_bytes,
7474                                                        aligned_cluster);
7475                         if (ret == 0) {
7476                                 /*
7477                                  * now pull our allocation out of this
7478                                  * cluster
7479                                  */
7480                                 offset = btrfs_alloc_from_cluster(block_group,
7481                                                         last_ptr,
7482                                                         num_bytes,
7483                                                         search_start,
7484                                                         &max_extent_size);
7485                                 if (offset) {
7486                                         /* we found one, proceed */
7487                                         spin_unlock(&last_ptr->refill_lock);
7488                                         trace_btrfs_reserve_extent_cluster(
7489                                                 block_group, search_start,
7490                                                 num_bytes);
7491                                         goto checks;
7492                                 }
7493                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7494                                    && !failed_cluster_refill) {
7495                                 spin_unlock(&last_ptr->refill_lock);
7496
7497                                 failed_cluster_refill = true;
7498                                 wait_block_group_cache_progress(block_group,
7499                                        num_bytes + empty_cluster + empty_size);
7500                                 goto have_block_group;
7501                         }
7502
7503                         /*
7504                          * at this point we either didn't find a cluster
7505                          * or we weren't able to allocate a block from our
7506                          * cluster.  Free the cluster we've been trying
7507                          * to use, and go to the next block group
7508                          */
7509                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7510                         spin_unlock(&last_ptr->refill_lock);
7511                         goto loop;
7512                 }
7513
7514 unclustered_alloc:
7515                 /*
7516                  * We are doing an unclustered alloc, set the fragmented flag so
7517                  * we don't bother trying to setup a cluster again until we get
7518                  * more space.
7519                  */
7520                 if (unlikely(last_ptr)) {
7521                         spin_lock(&last_ptr->lock);
7522                         last_ptr->fragmented = 1;
7523                         spin_unlock(&last_ptr->lock);
7524                 }
7525                 if (cached) {
7526                         struct btrfs_free_space_ctl *ctl =
7527                                 block_group->free_space_ctl;
7528
7529                         spin_lock(&ctl->tree_lock);
7530                         if (ctl->free_space <
7531                             num_bytes + empty_cluster + empty_size) {
7532                                 max_free_space = max(max_free_space,
7533                                                      ctl->free_space);
7534                                 spin_unlock(&ctl->tree_lock);
7535                                 goto loop;
7536                         }
7537                         spin_unlock(&ctl->tree_lock);
7538                 }
7539
7540                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7541                                                     num_bytes, empty_size,
7542                                                     &max_extent_size);
7543                 /*
7544                  * If we didn't find a chunk, and we haven't failed on this
7545                  * block group before, and this block group is in the middle of
7546                  * caching and we are ok with waiting, then go ahead and wait
7547                  * for progress to be made, and set failed_alloc to true.
7548                  *
7549                  * If failed_alloc is true then we've already waited on this
7550                  * block group once and should move on to the next block group.
7551                  */
7552                 if (!offset && !failed_alloc && !cached &&
7553                     loop > LOOP_CACHING_NOWAIT) {
7554                         wait_block_group_cache_progress(block_group,
7555                                                 num_bytes + empty_size);
7556                         failed_alloc = true;
7557                         goto have_block_group;
7558                 } else if (!offset) {
7559                         goto loop;
7560                 }
7561 checks:
7562                 search_start = round_up(offset, fs_info->stripesize);
7563
7564                 /* move on to the next group */
7565                 if (search_start + num_bytes >
7566                     block_group->key.objectid + block_group->key.offset) {
7567                         btrfs_add_free_space(block_group, offset, num_bytes);
7568                         goto loop;
7569                 }
7570
7571                 if (offset < search_start)
7572                         btrfs_add_free_space(block_group, offset,
7573                                              search_start - offset);
7574
7575                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7576                                 num_bytes, delalloc);
7577                 if (ret == -EAGAIN) {
7578                         btrfs_add_free_space(block_group, offset, num_bytes);
7579                         goto loop;
7580                 }
7581                 btrfs_inc_block_group_reservations(block_group);
7582
7583                 /* we are all good, lets return */
7584                 ins->objectid = search_start;
7585                 ins->offset = num_bytes;
7586
7587                 trace_btrfs_reserve_extent(block_group, search_start, num_bytes);
7588                 btrfs_release_block_group(block_group, delalloc);
7589                 break;
7590 loop:
7591                 failed_cluster_refill = false;
7592                 failed_alloc = false;
7593                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7594                        index);
7595                 btrfs_release_block_group(block_group, delalloc);
7596                 cond_resched();
7597         }
7598         up_read(&space_info->groups_sem);
7599
7600         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7601                 && !orig_have_caching_bg)
7602                 orig_have_caching_bg = true;
7603
7604         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7605                 goto search;
7606
7607         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7608                 goto search;
7609
7610         /*
7611          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7612          *                      caching kthreads as we move along
7613          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7614          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7615          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7616          *                      again
7617          */
7618         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7619                 index = 0;
7620                 if (loop == LOOP_CACHING_NOWAIT) {
7621                         /*
7622                          * We want to skip the LOOP_CACHING_WAIT step if we
7623                          * don't have any uncached bgs and we've already done a
7624                          * full search through.
7625                          */
7626                         if (orig_have_caching_bg || !full_search)
7627                                 loop = LOOP_CACHING_WAIT;
7628                         else
7629                                 loop = LOOP_ALLOC_CHUNK;
7630                 } else {
7631                         loop++;
7632                 }
7633
7634                 if (loop == LOOP_ALLOC_CHUNK) {
7635                         struct btrfs_trans_handle *trans;
7636                         int exist = 0;
7637
7638                         trans = current->journal_info;
7639                         if (trans)
7640                                 exist = 1;
7641                         else
7642                                 trans = btrfs_join_transaction(root);
7643
7644                         if (IS_ERR(trans)) {
7645                                 ret = PTR_ERR(trans);
7646                                 goto out;
7647                         }
7648
7649                         ret = do_chunk_alloc(trans, flags, CHUNK_ALLOC_FORCE);
7650
7651                         /*
7652                          * If we can't allocate a new chunk we've already looped
7653                          * through at least once, move on to the NO_EMPTY_SIZE
7654                          * case.
7655                          */
7656                         if (ret == -ENOSPC)
7657                                 loop = LOOP_NO_EMPTY_SIZE;
7658
7659                         /*
7660                          * Do not bail out on ENOSPC since we
7661                          * can do more things.
7662                          */
7663                         if (ret < 0 && ret != -ENOSPC)
7664                                 btrfs_abort_transaction(trans, ret);
7665                         else
7666                                 ret = 0;
7667                         if (!exist)
7668                                 btrfs_end_transaction(trans);
7669                         if (ret)
7670                                 goto out;
7671                 }
7672
7673                 if (loop == LOOP_NO_EMPTY_SIZE) {
7674                         /*
7675                          * Don't loop again if we already have no empty_size and
7676                          * no empty_cluster.
7677                          */
7678                         if (empty_size == 0 &&
7679                             empty_cluster == 0) {
7680                                 ret = -ENOSPC;
7681                                 goto out;
7682                         }
7683                         empty_size = 0;
7684                         empty_cluster = 0;
7685                 }
7686
7687                 goto search;
7688         } else if (!ins->objectid) {
7689                 ret = -ENOSPC;
7690         } else if (ins->objectid) {
7691                 if (!use_cluster && last_ptr) {
7692                         spin_lock(&last_ptr->lock);
7693                         last_ptr->window_start = ins->objectid;
7694                         spin_unlock(&last_ptr->lock);
7695                 }
7696                 ret = 0;
7697         }
7698 out:
7699         if (ret == -ENOSPC) {
7700                 if (!max_extent_size)
7701                         max_extent_size = max_free_space;
7702                 spin_lock(&space_info->lock);
7703                 space_info->max_extent_size = max_extent_size;
7704                 spin_unlock(&space_info->lock);
7705                 ins->offset = max_extent_size;
7706         }
7707         return ret;
7708 }
7709
7710 static void dump_space_info(struct btrfs_fs_info *fs_info,
7711                             struct btrfs_space_info *info, u64 bytes,
7712                             int dump_block_groups)
7713 {
7714         struct btrfs_block_group_cache *cache;
7715         int index = 0;
7716
7717         spin_lock(&info->lock);
7718         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7719                    info->flags,
7720                    info->total_bytes - btrfs_space_info_used(info, true),
7721                    info->full ? "" : "not ");
7722         btrfs_info(fs_info,
7723                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7724                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7725                 info->bytes_reserved, info->bytes_may_use,
7726                 info->bytes_readonly);
7727         spin_unlock(&info->lock);
7728
7729         if (!dump_block_groups)
7730                 return;
7731
7732         down_read(&info->groups_sem);
7733 again:
7734         list_for_each_entry(cache, &info->block_groups[index], list) {
7735                 spin_lock(&cache->lock);
7736                 btrfs_info(fs_info,
7737                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7738                         cache->key.objectid, cache->key.offset,
7739                         btrfs_block_group_used(&cache->item), cache->pinned,
7740                         cache->reserved, cache->ro ? "[readonly]" : "");
7741                 btrfs_dump_free_space(cache, bytes);
7742                 spin_unlock(&cache->lock);
7743         }
7744         if (++index < BTRFS_NR_RAID_TYPES)
7745                 goto again;
7746         up_read(&info->groups_sem);
7747 }
7748
7749 /*
7750  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7751  *                        hole that is at least as big as @num_bytes.
7752  *
7753  * @root           -    The root that will contain this extent
7754  *
7755  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7756  *                      is used for accounting purposes. This value differs
7757  *                      from @num_bytes only in the case of compressed extents.
7758  *
7759  * @num_bytes      -    Number of bytes to allocate on-disk.
7760  *
7761  * @min_alloc_size -    Indicates the minimum amount of space that the
7762  *                      allocator should try to satisfy. In some cases
7763  *                      @num_bytes may be larger than what is required and if
7764  *                      the filesystem is fragmented then allocation fails.
7765  *                      However, the presence of @min_alloc_size gives a
7766  *                      chance to try and satisfy the smaller allocation.
7767  *
7768  * @empty_size     -    A hint that you plan on doing more COW. This is the
7769  *                      size in bytes the allocator should try to find free
7770  *                      next to the block it returns.  This is just a hint and
7771  *                      may be ignored by the allocator.
7772  *
7773  * @hint_byte      -    Hint to the allocator to start searching above the byte
7774  *                      address passed. It might be ignored.
7775  *
7776  * @ins            -    This key is modified to record the found hole. It will
7777  *                      have the following values:
7778  *                      ins->objectid == start position
7779  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7780  *                      ins->offset == the size of the hole.
7781  *
7782  * @is_data        -    Boolean flag indicating whether an extent is
7783  *                      allocated for data (true) or metadata (false)
7784  *
7785  * @delalloc       -    Boolean flag indicating whether this allocation is for
7786  *                      delalloc or not. If 'true' data_rwsem of block groups
7787  *                      is going to be acquired.
7788  *
7789  *
7790  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7791  * case -ENOSPC is returned then @ins->offset will contain the size of the
7792  * largest available hole the allocator managed to find.
7793  */
7794 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7795                          u64 num_bytes, u64 min_alloc_size,
7796                          u64 empty_size, u64 hint_byte,
7797                          struct btrfs_key *ins, int is_data, int delalloc)
7798 {
7799         struct btrfs_fs_info *fs_info = root->fs_info;
7800         bool final_tried = num_bytes == min_alloc_size;
7801         u64 flags;
7802         int ret;
7803
7804         flags = get_alloc_profile_by_root(root, is_data);
7805 again:
7806         WARN_ON(num_bytes < fs_info->sectorsize);
7807         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7808                                hint_byte, ins, flags, delalloc);
7809         if (!ret && !is_data) {
7810                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7811         } else if (ret == -ENOSPC) {
7812                 if (!final_tried && ins->offset) {
7813                         num_bytes = min(num_bytes >> 1, ins->offset);
7814                         num_bytes = round_down(num_bytes,
7815                                                fs_info->sectorsize);
7816                         num_bytes = max(num_bytes, min_alloc_size);
7817                         ram_bytes = num_bytes;
7818                         if (num_bytes == min_alloc_size)
7819                                 final_tried = true;
7820                         goto again;
7821                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7822                         struct btrfs_space_info *sinfo;
7823
7824                         sinfo = __find_space_info(fs_info, flags);
7825                         btrfs_err(fs_info,
7826                                   "allocation failed flags %llu, wanted %llu",
7827                                   flags, num_bytes);
7828                         if (sinfo)
7829                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
7830                 }
7831         }
7832
7833         return ret;
7834 }
7835
7836 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7837                                         u64 start, u64 len,
7838                                         int pin, int delalloc)
7839 {
7840         struct btrfs_block_group_cache *cache;
7841         int ret = 0;
7842
7843         cache = btrfs_lookup_block_group(fs_info, start);
7844         if (!cache) {
7845                 btrfs_err(fs_info, "Unable to find block group for %llu",
7846                           start);
7847                 return -ENOSPC;
7848         }
7849
7850         if (pin)
7851                 pin_down_extent(fs_info, cache, start, len, 1);
7852         else {
7853                 if (btrfs_test_opt(fs_info, DISCARD))
7854                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
7855                 btrfs_add_free_space(cache, start, len);
7856                 btrfs_free_reserved_bytes(cache, len, delalloc);
7857                 trace_btrfs_reserved_extent_free(fs_info, start, len);
7858         }
7859
7860         btrfs_put_block_group(cache);
7861         return ret;
7862 }
7863
7864 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7865                                u64 start, u64 len, int delalloc)
7866 {
7867         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
7868 }
7869
7870 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
7871                                        u64 start, u64 len)
7872 {
7873         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
7874 }
7875
7876 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7877                                       u64 parent, u64 root_objectid,
7878                                       u64 flags, u64 owner, u64 offset,
7879                                       struct btrfs_key *ins, int ref_mod)
7880 {
7881         struct btrfs_fs_info *fs_info = trans->fs_info;
7882         int ret;
7883         struct btrfs_extent_item *extent_item;
7884         struct btrfs_extent_inline_ref *iref;
7885         struct btrfs_path *path;
7886         struct extent_buffer *leaf;
7887         int type;
7888         u32 size;
7889
7890         if (parent > 0)
7891                 type = BTRFS_SHARED_DATA_REF_KEY;
7892         else
7893                 type = BTRFS_EXTENT_DATA_REF_KEY;
7894
7895         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7896
7897         path = btrfs_alloc_path();
7898         if (!path)
7899                 return -ENOMEM;
7900
7901         path->leave_spinning = 1;
7902         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7903                                       ins, size);
7904         if (ret) {
7905                 btrfs_free_path(path);
7906                 return ret;
7907         }
7908
7909         leaf = path->nodes[0];
7910         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7911                                      struct btrfs_extent_item);
7912         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7913         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7914         btrfs_set_extent_flags(leaf, extent_item,
7915                                flags | BTRFS_EXTENT_FLAG_DATA);
7916
7917         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7918         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7919         if (parent > 0) {
7920                 struct btrfs_shared_data_ref *ref;
7921                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7922                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7923                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7924         } else {
7925                 struct btrfs_extent_data_ref *ref;
7926                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7927                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7928                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7929                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7930                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7931         }
7932
7933         btrfs_mark_buffer_dirty(path->nodes[0]);
7934         btrfs_free_path(path);
7935
7936         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
7937         if (ret)
7938                 return ret;
7939
7940         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
7941         if (ret) { /* -ENOENT, logic error */
7942                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7943                         ins->objectid, ins->offset);
7944                 BUG();
7945         }
7946         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
7947         return ret;
7948 }
7949
7950 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7951                                      struct btrfs_delayed_ref_node *node,
7952                                      struct btrfs_delayed_extent_op *extent_op)
7953 {
7954         struct btrfs_fs_info *fs_info = trans->fs_info;
7955         int ret;
7956         struct btrfs_extent_item *extent_item;
7957         struct btrfs_key extent_key;
7958         struct btrfs_tree_block_info *block_info;
7959         struct btrfs_extent_inline_ref *iref;
7960         struct btrfs_path *path;
7961         struct extent_buffer *leaf;
7962         struct btrfs_delayed_tree_ref *ref;
7963         u32 size = sizeof(*extent_item) + sizeof(*iref);
7964         u64 num_bytes;
7965         u64 flags = extent_op->flags_to_set;
7966         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
7967
7968         ref = btrfs_delayed_node_to_tree_ref(node);
7969
7970         extent_key.objectid = node->bytenr;
7971         if (skinny_metadata) {
7972                 extent_key.offset = ref->level;
7973                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
7974                 num_bytes = fs_info->nodesize;
7975         } else {
7976                 extent_key.offset = node->num_bytes;
7977                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
7978                 size += sizeof(*block_info);
7979                 num_bytes = node->num_bytes;
7980         }
7981
7982         path = btrfs_alloc_path();
7983         if (!path)
7984                 return -ENOMEM;
7985
7986         path->leave_spinning = 1;
7987         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7988                                       &extent_key, size);
7989         if (ret) {
7990                 btrfs_free_path(path);
7991                 return ret;
7992         }
7993
7994         leaf = path->nodes[0];
7995         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7996                                      struct btrfs_extent_item);
7997         btrfs_set_extent_refs(leaf, extent_item, 1);
7998         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7999         btrfs_set_extent_flags(leaf, extent_item,
8000                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8001
8002         if (skinny_metadata) {
8003                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8004         } else {
8005                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8006                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
8007                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
8008                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8009         }
8010
8011         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
8012                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8013                 btrfs_set_extent_inline_ref_type(leaf, iref,
8014                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8015                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
8016         } else {
8017                 btrfs_set_extent_inline_ref_type(leaf, iref,
8018                                                  BTRFS_TREE_BLOCK_REF_KEY);
8019                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
8020         }
8021
8022         btrfs_mark_buffer_dirty(leaf);
8023         btrfs_free_path(path);
8024
8025         ret = remove_from_free_space_tree(trans, extent_key.objectid,
8026                                           num_bytes);
8027         if (ret)
8028                 return ret;
8029
8030         ret = update_block_group(trans, fs_info, extent_key.objectid,
8031                                  fs_info->nodesize, 1);
8032         if (ret) { /* -ENOENT, logic error */
8033                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8034                         extent_key.objectid, extent_key.offset);
8035                 BUG();
8036         }
8037
8038         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
8039                                           fs_info->nodesize);
8040         return ret;
8041 }
8042
8043 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8044                                      struct btrfs_root *root, u64 owner,
8045                                      u64 offset, u64 ram_bytes,
8046                                      struct btrfs_key *ins)
8047 {
8048         int ret;
8049
8050         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8051
8052         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8053                            root->root_key.objectid, owner, offset,
8054                            BTRFS_ADD_DELAYED_EXTENT);
8055
8056         ret = btrfs_add_delayed_data_ref(trans, ins->objectid,
8057                                          ins->offset, 0,
8058                                          root->root_key.objectid, owner,
8059                                          offset, ram_bytes,
8060                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8061         return ret;
8062 }
8063
8064 /*
8065  * this is used by the tree logging recovery code.  It records that
8066  * an extent has been allocated and makes sure to clear the free
8067  * space cache bits as well
8068  */
8069 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8070                                    u64 root_objectid, u64 owner, u64 offset,
8071                                    struct btrfs_key *ins)
8072 {
8073         struct btrfs_fs_info *fs_info = trans->fs_info;
8074         int ret;
8075         struct btrfs_block_group_cache *block_group;
8076         struct btrfs_space_info *space_info;
8077
8078         /*
8079          * Mixed block groups will exclude before processing the log so we only
8080          * need to do the exclude dance if this fs isn't mixed.
8081          */
8082         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8083                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8084                                               ins->offset);
8085                 if (ret)
8086                         return ret;
8087         }
8088
8089         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8090         if (!block_group)
8091                 return -EINVAL;
8092
8093         space_info = block_group->space_info;
8094         spin_lock(&space_info->lock);
8095         spin_lock(&block_group->lock);
8096         space_info->bytes_reserved += ins->offset;
8097         block_group->reserved += ins->offset;
8098         spin_unlock(&block_group->lock);
8099         spin_unlock(&space_info->lock);
8100
8101         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
8102                                          offset, ins, 1);
8103         btrfs_put_block_group(block_group);
8104         return ret;
8105 }
8106
8107 static struct extent_buffer *
8108 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8109                       u64 bytenr, int level, u64 owner)
8110 {
8111         struct btrfs_fs_info *fs_info = root->fs_info;
8112         struct extent_buffer *buf;
8113
8114         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8115         if (IS_ERR(buf))
8116                 return buf;
8117
8118         /*
8119          * Extra safety check in case the extent tree is corrupted and extent
8120          * allocator chooses to use a tree block which is already used and
8121          * locked.
8122          */
8123         if (buf->lock_owner == current->pid) {
8124                 btrfs_err_rl(fs_info,
8125 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
8126                         buf->start, btrfs_header_owner(buf), current->pid);
8127                 free_extent_buffer(buf);
8128                 return ERR_PTR(-EUCLEAN);
8129         }
8130
8131         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8132         btrfs_tree_lock(buf);
8133         clean_tree_block(fs_info, buf);
8134         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8135
8136         btrfs_set_lock_blocking(buf);
8137         set_extent_buffer_uptodate(buf);
8138
8139         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
8140         btrfs_set_header_level(buf, level);
8141         btrfs_set_header_bytenr(buf, buf->start);
8142         btrfs_set_header_generation(buf, trans->transid);
8143         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
8144         btrfs_set_header_owner(buf, owner);
8145         write_extent_buffer_fsid(buf, fs_info->fsid);
8146         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
8147         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8148                 buf->log_index = root->log_transid % 2;
8149                 /*
8150                  * we allow two log transactions at a time, use different
8151                  * EXENT bit to differentiate dirty pages.
8152                  */
8153                 if (buf->log_index == 0)
8154                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8155                                         buf->start + buf->len - 1, GFP_NOFS);
8156                 else
8157                         set_extent_new(&root->dirty_log_pages, buf->start,
8158                                         buf->start + buf->len - 1);
8159         } else {
8160                 buf->log_index = -1;
8161                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8162                          buf->start + buf->len - 1, GFP_NOFS);
8163         }
8164         trans->dirty = true;
8165         /* this returns a buffer locked for blocking */
8166         return buf;
8167 }
8168
8169 static struct btrfs_block_rsv *
8170 use_block_rsv(struct btrfs_trans_handle *trans,
8171               struct btrfs_root *root, u32 blocksize)
8172 {
8173         struct btrfs_fs_info *fs_info = root->fs_info;
8174         struct btrfs_block_rsv *block_rsv;
8175         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8176         int ret;
8177         bool global_updated = false;
8178
8179         block_rsv = get_block_rsv(trans, root);
8180
8181         if (unlikely(block_rsv->size == 0))
8182                 goto try_reserve;
8183 again:
8184         ret = block_rsv_use_bytes(block_rsv, blocksize);
8185         if (!ret)
8186                 return block_rsv;
8187
8188         if (block_rsv->failfast)
8189                 return ERR_PTR(ret);
8190
8191         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8192                 global_updated = true;
8193                 update_global_block_rsv(fs_info);
8194                 goto again;
8195         }
8196
8197         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8198                 static DEFINE_RATELIMIT_STATE(_rs,
8199                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8200                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8201                 if (__ratelimit(&_rs))
8202                         WARN(1, KERN_DEBUG
8203                                 "BTRFS: block rsv returned %d\n", ret);
8204         }
8205 try_reserve:
8206         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8207                                      BTRFS_RESERVE_NO_FLUSH);
8208         if (!ret)
8209                 return block_rsv;
8210         /*
8211          * If we couldn't reserve metadata bytes try and use some from
8212          * the global reserve if its space type is the same as the global
8213          * reservation.
8214          */
8215         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8216             block_rsv->space_info == global_rsv->space_info) {
8217                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8218                 if (!ret)
8219                         return global_rsv;
8220         }
8221         return ERR_PTR(ret);
8222 }
8223
8224 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8225                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8226 {
8227         block_rsv_add_bytes(block_rsv, blocksize, 0);
8228         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0, NULL);
8229 }
8230
8231 /*
8232  * finds a free extent and does all the dirty work required for allocation
8233  * returns the tree buffer or an ERR_PTR on error.
8234  */
8235 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8236                                              struct btrfs_root *root,
8237                                              u64 parent, u64 root_objectid,
8238                                              const struct btrfs_disk_key *key,
8239                                              int level, u64 hint,
8240                                              u64 empty_size)
8241 {
8242         struct btrfs_fs_info *fs_info = root->fs_info;
8243         struct btrfs_key ins;
8244         struct btrfs_block_rsv *block_rsv;
8245         struct extent_buffer *buf;
8246         struct btrfs_delayed_extent_op *extent_op;
8247         u64 flags = 0;
8248         int ret;
8249         u32 blocksize = fs_info->nodesize;
8250         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8251
8252 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8253         if (btrfs_is_testing(fs_info)) {
8254                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8255                                             level, root_objectid);
8256                 if (!IS_ERR(buf))
8257                         root->alloc_bytenr += blocksize;
8258                 return buf;
8259         }
8260 #endif
8261
8262         block_rsv = use_block_rsv(trans, root, blocksize);
8263         if (IS_ERR(block_rsv))
8264                 return ERR_CAST(block_rsv);
8265
8266         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8267                                    empty_size, hint, &ins, 0, 0);
8268         if (ret)
8269                 goto out_unuse;
8270
8271         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
8272                                     root_objectid);
8273         if (IS_ERR(buf)) {
8274                 ret = PTR_ERR(buf);
8275                 goto out_free_reserved;
8276         }
8277
8278         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8279                 if (parent == 0)
8280                         parent = ins.objectid;
8281                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8282         } else
8283                 BUG_ON(parent > 0);
8284
8285         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8286                 extent_op = btrfs_alloc_delayed_extent_op();
8287                 if (!extent_op) {
8288                         ret = -ENOMEM;
8289                         goto out_free_buf;
8290                 }
8291                 if (key)
8292                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8293                 else
8294                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8295                 extent_op->flags_to_set = flags;
8296                 extent_op->update_key = skinny_metadata ? false : true;
8297                 extent_op->update_flags = true;
8298                 extent_op->is_data = false;
8299                 extent_op->level = level;
8300
8301                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8302                                    root_objectid, level, 0,
8303                                    BTRFS_ADD_DELAYED_EXTENT);
8304                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
8305                                                  ins.offset, parent,
8306                                                  root_objectid, level,
8307                                                  BTRFS_ADD_DELAYED_EXTENT,
8308                                                  extent_op, NULL, NULL);
8309                 if (ret)
8310                         goto out_free_delayed;
8311         }
8312         return buf;
8313
8314 out_free_delayed:
8315         btrfs_free_delayed_extent_op(extent_op);
8316 out_free_buf:
8317         free_extent_buffer(buf);
8318 out_free_reserved:
8319         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8320 out_unuse:
8321         unuse_block_rsv(fs_info, block_rsv, blocksize);
8322         return ERR_PTR(ret);
8323 }
8324
8325 struct walk_control {
8326         u64 refs[BTRFS_MAX_LEVEL];
8327         u64 flags[BTRFS_MAX_LEVEL];
8328         struct btrfs_key update_progress;
8329         int stage;
8330         int level;
8331         int shared_level;
8332         int update_ref;
8333         int keep_locks;
8334         int reada_slot;
8335         int reada_count;
8336 };
8337
8338 #define DROP_REFERENCE  1
8339 #define UPDATE_BACKREF  2
8340
8341 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8342                                      struct btrfs_root *root,
8343                                      struct walk_control *wc,
8344                                      struct btrfs_path *path)
8345 {
8346         struct btrfs_fs_info *fs_info = root->fs_info;
8347         u64 bytenr;
8348         u64 generation;
8349         u64 refs;
8350         u64 flags;
8351         u32 nritems;
8352         struct btrfs_key key;
8353         struct extent_buffer *eb;
8354         int ret;
8355         int slot;
8356         int nread = 0;
8357
8358         if (path->slots[wc->level] < wc->reada_slot) {
8359                 wc->reada_count = wc->reada_count * 2 / 3;
8360                 wc->reada_count = max(wc->reada_count, 2);
8361         } else {
8362                 wc->reada_count = wc->reada_count * 3 / 2;
8363                 wc->reada_count = min_t(int, wc->reada_count,
8364                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8365         }
8366
8367         eb = path->nodes[wc->level];
8368         nritems = btrfs_header_nritems(eb);
8369
8370         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8371                 if (nread >= wc->reada_count)
8372                         break;
8373
8374                 cond_resched();
8375                 bytenr = btrfs_node_blockptr(eb, slot);
8376                 generation = btrfs_node_ptr_generation(eb, slot);
8377
8378                 if (slot == path->slots[wc->level])
8379                         goto reada;
8380
8381                 if (wc->stage == UPDATE_BACKREF &&
8382                     generation <= root->root_key.offset)
8383                         continue;
8384
8385                 /* We don't lock the tree block, it's OK to be racy here */
8386                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8387                                                wc->level - 1, 1, &refs,
8388                                                &flags);
8389                 /* We don't care about errors in readahead. */
8390                 if (ret < 0)
8391                         continue;
8392                 BUG_ON(refs == 0);
8393
8394                 if (wc->stage == DROP_REFERENCE) {
8395                         if (refs == 1)
8396                                 goto reada;
8397
8398                         if (wc->level == 1 &&
8399                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8400                                 continue;
8401                         if (!wc->update_ref ||
8402                             generation <= root->root_key.offset)
8403                                 continue;
8404                         btrfs_node_key_to_cpu(eb, &key, slot);
8405                         ret = btrfs_comp_cpu_keys(&key,
8406                                                   &wc->update_progress);
8407                         if (ret < 0)
8408                                 continue;
8409                 } else {
8410                         if (wc->level == 1 &&
8411                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8412                                 continue;
8413                 }
8414 reada:
8415                 readahead_tree_block(fs_info, bytenr);
8416                 nread++;
8417         }
8418         wc->reada_slot = slot;
8419 }
8420
8421 /*
8422  * helper to process tree block while walking down the tree.
8423  *
8424  * when wc->stage == UPDATE_BACKREF, this function updates
8425  * back refs for pointers in the block.
8426  *
8427  * NOTE: return value 1 means we should stop walking down.
8428  */
8429 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8430                                    struct btrfs_root *root,
8431                                    struct btrfs_path *path,
8432                                    struct walk_control *wc, int lookup_info)
8433 {
8434         struct btrfs_fs_info *fs_info = root->fs_info;
8435         int level = wc->level;
8436         struct extent_buffer *eb = path->nodes[level];
8437         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8438         int ret;
8439
8440         if (wc->stage == UPDATE_BACKREF &&
8441             btrfs_header_owner(eb) != root->root_key.objectid)
8442                 return 1;
8443
8444         /*
8445          * when reference count of tree block is 1, it won't increase
8446          * again. once full backref flag is set, we never clear it.
8447          */
8448         if (lookup_info &&
8449             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8450              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8451                 BUG_ON(!path->locks[level]);
8452                 ret = btrfs_lookup_extent_info(trans, fs_info,
8453                                                eb->start, level, 1,
8454                                                &wc->refs[level],
8455                                                &wc->flags[level]);
8456                 BUG_ON(ret == -ENOMEM);
8457                 if (ret)
8458                         return ret;
8459                 BUG_ON(wc->refs[level] == 0);
8460         }
8461
8462         if (wc->stage == DROP_REFERENCE) {
8463                 if (wc->refs[level] > 1)
8464                         return 1;
8465
8466                 if (path->locks[level] && !wc->keep_locks) {
8467                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8468                         path->locks[level] = 0;
8469                 }
8470                 return 0;
8471         }
8472
8473         /* wc->stage == UPDATE_BACKREF */
8474         if (!(wc->flags[level] & flag)) {
8475                 BUG_ON(!path->locks[level]);
8476                 ret = btrfs_inc_ref(trans, root, eb, 1);
8477                 BUG_ON(ret); /* -ENOMEM */
8478                 ret = btrfs_dec_ref(trans, root, eb, 0);
8479                 BUG_ON(ret); /* -ENOMEM */
8480                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8481                                                   eb->len, flag,
8482                                                   btrfs_header_level(eb), 0);
8483                 BUG_ON(ret); /* -ENOMEM */
8484                 wc->flags[level] |= flag;
8485         }
8486
8487         /*
8488          * the block is shared by multiple trees, so it's not good to
8489          * keep the tree lock
8490          */
8491         if (path->locks[level] && level > 0) {
8492                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8493                 path->locks[level] = 0;
8494         }
8495         return 0;
8496 }
8497
8498 /*
8499  * helper to process tree block pointer.
8500  *
8501  * when wc->stage == DROP_REFERENCE, this function checks
8502  * reference count of the block pointed to. if the block
8503  * is shared and we need update back refs for the subtree
8504  * rooted at the block, this function changes wc->stage to
8505  * UPDATE_BACKREF. if the block is shared and there is no
8506  * need to update back, this function drops the reference
8507  * to the block.
8508  *
8509  * NOTE: return value 1 means we should stop walking down.
8510  */
8511 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8512                                  struct btrfs_root *root,
8513                                  struct btrfs_path *path,
8514                                  struct walk_control *wc, int *lookup_info)
8515 {
8516         struct btrfs_fs_info *fs_info = root->fs_info;
8517         u64 bytenr;
8518         u64 generation;
8519         u64 parent;
8520         u32 blocksize;
8521         struct btrfs_key key;
8522         struct btrfs_key first_key;
8523         struct extent_buffer *next;
8524         int level = wc->level;
8525         int reada = 0;
8526         int ret = 0;
8527         bool need_account = false;
8528
8529         generation = btrfs_node_ptr_generation(path->nodes[level],
8530                                                path->slots[level]);
8531         /*
8532          * if the lower level block was created before the snapshot
8533          * was created, we know there is no need to update back refs
8534          * for the subtree
8535          */
8536         if (wc->stage == UPDATE_BACKREF &&
8537             generation <= root->root_key.offset) {
8538                 *lookup_info = 1;
8539                 return 1;
8540         }
8541
8542         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8543         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8544                               path->slots[level]);
8545         blocksize = fs_info->nodesize;
8546
8547         next = find_extent_buffer(fs_info, bytenr);
8548         if (!next) {
8549                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8550                 if (IS_ERR(next))
8551                         return PTR_ERR(next);
8552
8553                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8554                                                level - 1);
8555                 reada = 1;
8556         }
8557         btrfs_tree_lock(next);
8558         btrfs_set_lock_blocking(next);
8559
8560         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8561                                        &wc->refs[level - 1],
8562                                        &wc->flags[level - 1]);
8563         if (ret < 0)
8564                 goto out_unlock;
8565
8566         if (unlikely(wc->refs[level - 1] == 0)) {
8567                 btrfs_err(fs_info, "Missing references.");
8568                 ret = -EIO;
8569                 goto out_unlock;
8570         }
8571         *lookup_info = 0;
8572
8573         if (wc->stage == DROP_REFERENCE) {
8574                 if (wc->refs[level - 1] > 1) {
8575                         need_account = true;
8576                         if (level == 1 &&
8577                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8578                                 goto skip;
8579
8580                         if (!wc->update_ref ||
8581                             generation <= root->root_key.offset)
8582                                 goto skip;
8583
8584                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8585                                               path->slots[level]);
8586                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8587                         if (ret < 0)
8588                                 goto skip;
8589
8590                         wc->stage = UPDATE_BACKREF;
8591                         wc->shared_level = level - 1;
8592                 }
8593         } else {
8594                 if (level == 1 &&
8595                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8596                         goto skip;
8597         }
8598
8599         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8600                 btrfs_tree_unlock(next);
8601                 free_extent_buffer(next);
8602                 next = NULL;
8603                 *lookup_info = 1;
8604         }
8605
8606         if (!next) {
8607                 if (reada && level == 1)
8608                         reada_walk_down(trans, root, wc, path);
8609                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8610                                        &first_key);
8611                 if (IS_ERR(next)) {
8612                         return PTR_ERR(next);
8613                 } else if (!extent_buffer_uptodate(next)) {
8614                         free_extent_buffer(next);
8615                         return -EIO;
8616                 }
8617                 btrfs_tree_lock(next);
8618                 btrfs_set_lock_blocking(next);
8619         }
8620
8621         level--;
8622         ASSERT(level == btrfs_header_level(next));
8623         if (level != btrfs_header_level(next)) {
8624                 btrfs_err(root->fs_info, "mismatched level");
8625                 ret = -EIO;
8626                 goto out_unlock;
8627         }
8628         path->nodes[level] = next;
8629         path->slots[level] = 0;
8630         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8631         wc->level = level;
8632         if (wc->level == 1)
8633                 wc->reada_slot = 0;
8634         return 0;
8635 skip:
8636         wc->refs[level - 1] = 0;
8637         wc->flags[level - 1] = 0;
8638         if (wc->stage == DROP_REFERENCE) {
8639                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8640                         parent = path->nodes[level]->start;
8641                 } else {
8642                         ASSERT(root->root_key.objectid ==
8643                                btrfs_header_owner(path->nodes[level]));
8644                         if (root->root_key.objectid !=
8645                             btrfs_header_owner(path->nodes[level])) {
8646                                 btrfs_err(root->fs_info,
8647                                                 "mismatched block owner");
8648                                 ret = -EIO;
8649                                 goto out_unlock;
8650                         }
8651                         parent = 0;
8652                 }
8653
8654                 if (need_account) {
8655                         ret = btrfs_qgroup_trace_subtree(trans, next,
8656                                                          generation, level - 1);
8657                         if (ret) {
8658                                 btrfs_err_rl(fs_info,
8659                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8660                                              ret);
8661                         }
8662                 }
8663                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8664                                         parent, root->root_key.objectid,
8665                                         level - 1, 0);
8666                 if (ret)
8667                         goto out_unlock;
8668         }
8669
8670         *lookup_info = 1;
8671         ret = 1;
8672
8673 out_unlock:
8674         btrfs_tree_unlock(next);
8675         free_extent_buffer(next);
8676
8677         return ret;
8678 }
8679
8680 /*
8681  * helper to process tree block while walking up the tree.
8682  *
8683  * when wc->stage == DROP_REFERENCE, this function drops
8684  * reference count on the block.
8685  *
8686  * when wc->stage == UPDATE_BACKREF, this function changes
8687  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8688  * to UPDATE_BACKREF previously while processing the block.
8689  *
8690  * NOTE: return value 1 means we should stop walking up.
8691  */
8692 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8693                                  struct btrfs_root *root,
8694                                  struct btrfs_path *path,
8695                                  struct walk_control *wc)
8696 {
8697         struct btrfs_fs_info *fs_info = root->fs_info;
8698         int ret;
8699         int level = wc->level;
8700         struct extent_buffer *eb = path->nodes[level];
8701         u64 parent = 0;
8702
8703         if (wc->stage == UPDATE_BACKREF) {
8704                 BUG_ON(wc->shared_level < level);
8705                 if (level < wc->shared_level)
8706                         goto out;
8707
8708                 ret = find_next_key(path, level + 1, &wc->update_progress);
8709                 if (ret > 0)
8710                         wc->update_ref = 0;
8711
8712                 wc->stage = DROP_REFERENCE;
8713                 wc->shared_level = -1;
8714                 path->slots[level] = 0;
8715
8716                 /*
8717                  * check reference count again if the block isn't locked.
8718                  * we should start walking down the tree again if reference
8719                  * count is one.
8720                  */
8721                 if (!path->locks[level]) {
8722                         BUG_ON(level == 0);
8723                         btrfs_tree_lock(eb);
8724                         btrfs_set_lock_blocking(eb);
8725                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8726
8727                         ret = btrfs_lookup_extent_info(trans, fs_info,
8728                                                        eb->start, level, 1,
8729                                                        &wc->refs[level],
8730                                                        &wc->flags[level]);
8731                         if (ret < 0) {
8732                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8733                                 path->locks[level] = 0;
8734                                 return ret;
8735                         }
8736                         BUG_ON(wc->refs[level] == 0);
8737                         if (wc->refs[level] == 1) {
8738                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8739                                 path->locks[level] = 0;
8740                                 return 1;
8741                         }
8742                 }
8743         }
8744
8745         /* wc->stage == DROP_REFERENCE */
8746         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8747
8748         if (wc->refs[level] == 1) {
8749                 if (level == 0) {
8750                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8751                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8752                         else
8753                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8754                         BUG_ON(ret); /* -ENOMEM */
8755                         ret = btrfs_qgroup_trace_leaf_items(trans, eb);
8756                         if (ret) {
8757                                 btrfs_err_rl(fs_info,
8758                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8759                                              ret);
8760                         }
8761                 }
8762                 /* make block locked assertion in clean_tree_block happy */
8763                 if (!path->locks[level] &&
8764                     btrfs_header_generation(eb) == trans->transid) {
8765                         btrfs_tree_lock(eb);
8766                         btrfs_set_lock_blocking(eb);
8767                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8768                 }
8769                 clean_tree_block(fs_info, eb);
8770         }
8771
8772         if (eb == root->node) {
8773                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8774                         parent = eb->start;
8775                 else if (root->root_key.objectid != btrfs_header_owner(eb))
8776                         goto owner_mismatch;
8777         } else {
8778                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8779                         parent = path->nodes[level + 1]->start;
8780                 else if (root->root_key.objectid !=
8781                          btrfs_header_owner(path->nodes[level + 1]))
8782                         goto owner_mismatch;
8783         }
8784
8785         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8786 out:
8787         wc->refs[level] = 0;
8788         wc->flags[level] = 0;
8789         return 0;
8790
8791 owner_mismatch:
8792         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
8793                      btrfs_header_owner(eb), root->root_key.objectid);
8794         return -EUCLEAN;
8795 }
8796
8797 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8798                                    struct btrfs_root *root,
8799                                    struct btrfs_path *path,
8800                                    struct walk_control *wc)
8801 {
8802         int level = wc->level;
8803         int lookup_info = 1;
8804         int ret;
8805
8806         while (level >= 0) {
8807                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8808                 if (ret > 0)
8809                         break;
8810
8811                 if (level == 0)
8812                         break;
8813
8814                 if (path->slots[level] >=
8815                     btrfs_header_nritems(path->nodes[level]))
8816                         break;
8817
8818                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8819                 if (ret > 0) {
8820                         path->slots[level]++;
8821                         continue;
8822                 } else if (ret < 0)
8823                         return ret;
8824                 level = wc->level;
8825         }
8826         return 0;
8827 }
8828
8829 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8830                                  struct btrfs_root *root,
8831                                  struct btrfs_path *path,
8832                                  struct walk_control *wc, int max_level)
8833 {
8834         int level = wc->level;
8835         int ret;
8836
8837         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8838         while (level < max_level && path->nodes[level]) {
8839                 wc->level = level;
8840                 if (path->slots[level] + 1 <
8841                     btrfs_header_nritems(path->nodes[level])) {
8842                         path->slots[level]++;
8843                         return 0;
8844                 } else {
8845                         ret = walk_up_proc(trans, root, path, wc);
8846                         if (ret > 0)
8847                                 return 0;
8848                         if (ret < 0)
8849                                 return ret;
8850
8851                         if (path->locks[level]) {
8852                                 btrfs_tree_unlock_rw(path->nodes[level],
8853                                                      path->locks[level]);
8854                                 path->locks[level] = 0;
8855                         }
8856                         free_extent_buffer(path->nodes[level]);
8857                         path->nodes[level] = NULL;
8858                         level++;
8859                 }
8860         }
8861         return 1;
8862 }
8863
8864 /*
8865  * drop a subvolume tree.
8866  *
8867  * this function traverses the tree freeing any blocks that only
8868  * referenced by the tree.
8869  *
8870  * when a shared tree block is found. this function decreases its
8871  * reference count by one. if update_ref is true, this function
8872  * also make sure backrefs for the shared block and all lower level
8873  * blocks are properly updated.
8874  *
8875  * If called with for_reloc == 0, may exit early with -EAGAIN
8876  */
8877 int btrfs_drop_snapshot(struct btrfs_root *root,
8878                          struct btrfs_block_rsv *block_rsv, int update_ref,
8879                          int for_reloc)
8880 {
8881         struct btrfs_fs_info *fs_info = root->fs_info;
8882         struct btrfs_path *path;
8883         struct btrfs_trans_handle *trans;
8884         struct btrfs_root *tree_root = fs_info->tree_root;
8885         struct btrfs_root_item *root_item = &root->root_item;
8886         struct walk_control *wc;
8887         struct btrfs_key key;
8888         int err = 0;
8889         int ret;
8890         int level;
8891         bool root_dropped = false;
8892
8893         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
8894
8895         path = btrfs_alloc_path();
8896         if (!path) {
8897                 err = -ENOMEM;
8898                 goto out;
8899         }
8900
8901         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8902         if (!wc) {
8903                 btrfs_free_path(path);
8904                 err = -ENOMEM;
8905                 goto out;
8906         }
8907
8908         trans = btrfs_start_transaction(tree_root, 0);
8909         if (IS_ERR(trans)) {
8910                 err = PTR_ERR(trans);
8911                 goto out_free;
8912         }
8913
8914         err = btrfs_run_delayed_items(trans);
8915         if (err)
8916                 goto out_end_trans;
8917
8918         if (block_rsv)
8919                 trans->block_rsv = block_rsv;
8920
8921         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8922                 level = btrfs_header_level(root->node);
8923                 path->nodes[level] = btrfs_lock_root_node(root);
8924                 btrfs_set_lock_blocking(path->nodes[level]);
8925                 path->slots[level] = 0;
8926                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8927                 memset(&wc->update_progress, 0,
8928                        sizeof(wc->update_progress));
8929         } else {
8930                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8931                 memcpy(&wc->update_progress, &key,
8932                        sizeof(wc->update_progress));
8933
8934                 level = root_item->drop_level;
8935                 BUG_ON(level == 0);
8936                 path->lowest_level = level;
8937                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8938                 path->lowest_level = 0;
8939                 if (ret < 0) {
8940                         err = ret;
8941                         goto out_end_trans;
8942                 }
8943                 WARN_ON(ret > 0);
8944
8945                 /*
8946                  * unlock our path, this is safe because only this
8947                  * function is allowed to delete this snapshot
8948                  */
8949                 btrfs_unlock_up_safe(path, 0);
8950
8951                 level = btrfs_header_level(root->node);
8952                 while (1) {
8953                         btrfs_tree_lock(path->nodes[level]);
8954                         btrfs_set_lock_blocking(path->nodes[level]);
8955                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8956
8957                         ret = btrfs_lookup_extent_info(trans, fs_info,
8958                                                 path->nodes[level]->start,
8959                                                 level, 1, &wc->refs[level],
8960                                                 &wc->flags[level]);
8961                         if (ret < 0) {
8962                                 err = ret;
8963                                 goto out_end_trans;
8964                         }
8965                         BUG_ON(wc->refs[level] == 0);
8966
8967                         if (level == root_item->drop_level)
8968                                 break;
8969
8970                         btrfs_tree_unlock(path->nodes[level]);
8971                         path->locks[level] = 0;
8972                         WARN_ON(wc->refs[level] != 1);
8973                         level--;
8974                 }
8975         }
8976
8977         wc->level = level;
8978         wc->shared_level = -1;
8979         wc->stage = DROP_REFERENCE;
8980         wc->update_ref = update_ref;
8981         wc->keep_locks = 0;
8982         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
8983
8984         while (1) {
8985
8986                 ret = walk_down_tree(trans, root, path, wc);
8987                 if (ret < 0) {
8988                         err = ret;
8989                         break;
8990                 }
8991
8992                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8993                 if (ret < 0) {
8994                         err = ret;
8995                         break;
8996                 }
8997
8998                 if (ret > 0) {
8999                         BUG_ON(wc->stage != DROP_REFERENCE);
9000                         break;
9001                 }
9002
9003                 if (wc->stage == DROP_REFERENCE) {
9004                         level = wc->level;
9005                         btrfs_node_key(path->nodes[level],
9006                                        &root_item->drop_progress,
9007                                        path->slots[level]);
9008                         root_item->drop_level = level;
9009                 }
9010
9011                 BUG_ON(wc->level == 0);
9012                 if (btrfs_should_end_transaction(trans) ||
9013                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9014                         ret = btrfs_update_root(trans, tree_root,
9015                                                 &root->root_key,
9016                                                 root_item);
9017                         if (ret) {
9018                                 btrfs_abort_transaction(trans, ret);
9019                                 err = ret;
9020                                 goto out_end_trans;
9021                         }
9022
9023                         btrfs_end_transaction_throttle(trans);
9024                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9025                                 btrfs_debug(fs_info,
9026                                             "drop snapshot early exit");
9027                                 err = -EAGAIN;
9028                                 goto out_free;
9029                         }
9030
9031                         trans = btrfs_start_transaction(tree_root, 0);
9032                         if (IS_ERR(trans)) {
9033                                 err = PTR_ERR(trans);
9034                                 goto out_free;
9035                         }
9036                         if (block_rsv)
9037                                 trans->block_rsv = block_rsv;
9038                 }
9039         }
9040         btrfs_release_path(path);
9041         if (err)
9042                 goto out_end_trans;
9043
9044         ret = btrfs_del_root(trans, &root->root_key);
9045         if (ret) {
9046                 btrfs_abort_transaction(trans, ret);
9047                 err = ret;
9048                 goto out_end_trans;
9049         }
9050
9051         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9052                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9053                                       NULL, NULL);
9054                 if (ret < 0) {
9055                         btrfs_abort_transaction(trans, ret);
9056                         err = ret;
9057                         goto out_end_trans;
9058                 } else if (ret > 0) {
9059                         /* if we fail to delete the orphan item this time
9060                          * around, it'll get picked up the next time.
9061                          *
9062                          * The most common failure here is just -ENOENT.
9063                          */
9064                         btrfs_del_orphan_item(trans, tree_root,
9065                                               root->root_key.objectid);
9066                 }
9067         }
9068
9069         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9070                 btrfs_add_dropped_root(trans, root);
9071         } else {
9072                 free_extent_buffer(root->node);
9073                 free_extent_buffer(root->commit_root);
9074                 btrfs_put_fs_root(root);
9075         }
9076         root_dropped = true;
9077 out_end_trans:
9078         btrfs_end_transaction_throttle(trans);
9079 out_free:
9080         kfree(wc);
9081         btrfs_free_path(path);
9082 out:
9083         /*
9084          * So if we need to stop dropping the snapshot for whatever reason we
9085          * need to make sure to add it back to the dead root list so that we
9086          * keep trying to do the work later.  This also cleans up roots if we
9087          * don't have it in the radix (like when we recover after a power fail
9088          * or unmount) so we don't leak memory.
9089          */
9090         if (!for_reloc && !root_dropped)
9091                 btrfs_add_dead_root(root);
9092         if (err && err != -EAGAIN)
9093                 btrfs_handle_fs_error(fs_info, err, NULL);
9094         return err;
9095 }
9096
9097 /*
9098  * drop subtree rooted at tree block 'node'.
9099  *
9100  * NOTE: this function will unlock and release tree block 'node'
9101  * only used by relocation code
9102  */
9103 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9104                         struct btrfs_root *root,
9105                         struct extent_buffer *node,
9106                         struct extent_buffer *parent)
9107 {
9108         struct btrfs_fs_info *fs_info = root->fs_info;
9109         struct btrfs_path *path;
9110         struct walk_control *wc;
9111         int level;
9112         int parent_level;
9113         int ret = 0;
9114         int wret;
9115
9116         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9117
9118         path = btrfs_alloc_path();
9119         if (!path)
9120                 return -ENOMEM;
9121
9122         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9123         if (!wc) {
9124                 btrfs_free_path(path);
9125                 return -ENOMEM;
9126         }
9127
9128         btrfs_assert_tree_locked(parent);
9129         parent_level = btrfs_header_level(parent);
9130         extent_buffer_get(parent);
9131         path->nodes[parent_level] = parent;
9132         path->slots[parent_level] = btrfs_header_nritems(parent);
9133
9134         btrfs_assert_tree_locked(node);
9135         level = btrfs_header_level(node);
9136         path->nodes[level] = node;
9137         path->slots[level] = 0;
9138         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9139
9140         wc->refs[parent_level] = 1;
9141         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9142         wc->level = level;
9143         wc->shared_level = -1;
9144         wc->stage = DROP_REFERENCE;
9145         wc->update_ref = 0;
9146         wc->keep_locks = 1;
9147         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9148
9149         while (1) {
9150                 wret = walk_down_tree(trans, root, path, wc);
9151                 if (wret < 0) {
9152                         ret = wret;
9153                         break;
9154                 }
9155
9156                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9157                 if (wret < 0)
9158                         ret = wret;
9159                 if (wret != 0)
9160                         break;
9161         }
9162
9163         kfree(wc);
9164         btrfs_free_path(path);
9165         return ret;
9166 }
9167
9168 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9169 {
9170         u64 num_devices;
9171         u64 stripped;
9172
9173         /*
9174          * if restripe for this chunk_type is on pick target profile and
9175          * return, otherwise do the usual balance
9176          */
9177         stripped = get_restripe_target(fs_info, flags);
9178         if (stripped)
9179                 return extended_to_chunk(stripped);
9180
9181         num_devices = fs_info->fs_devices->rw_devices;
9182
9183         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9184                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9185                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9186
9187         if (num_devices == 1) {
9188                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9189                 stripped = flags & ~stripped;
9190
9191                 /* turn raid0 into single device chunks */
9192                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9193                         return stripped;
9194
9195                 /* turn mirroring into duplication */
9196                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9197                              BTRFS_BLOCK_GROUP_RAID10))
9198                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9199         } else {
9200                 /* they already had raid on here, just return */
9201                 if (flags & stripped)
9202                         return flags;
9203
9204                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9205                 stripped = flags & ~stripped;
9206
9207                 /* switch duplicated blocks with raid1 */
9208                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9209                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9210
9211                 /* this is drive concat, leave it alone */
9212         }
9213
9214         return flags;
9215 }
9216
9217 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9218 {
9219         struct btrfs_space_info *sinfo = cache->space_info;
9220         u64 num_bytes;
9221         u64 min_allocable_bytes;
9222         int ret = -ENOSPC;
9223
9224         /*
9225          * We need some metadata space and system metadata space for
9226          * allocating chunks in some corner cases until we force to set
9227          * it to be readonly.
9228          */
9229         if ((sinfo->flags &
9230              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9231             !force)
9232                 min_allocable_bytes = SZ_1M;
9233         else
9234                 min_allocable_bytes = 0;
9235
9236         spin_lock(&sinfo->lock);
9237         spin_lock(&cache->lock);
9238
9239         if (cache->ro) {
9240                 cache->ro++;
9241                 ret = 0;
9242                 goto out;
9243         }
9244
9245         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9246                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9247
9248         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9249             min_allocable_bytes <= sinfo->total_bytes) {
9250                 sinfo->bytes_readonly += num_bytes;
9251                 cache->ro++;
9252                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9253                 ret = 0;
9254         }
9255 out:
9256         spin_unlock(&cache->lock);
9257         spin_unlock(&sinfo->lock);
9258         return ret;
9259 }
9260
9261 int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
9262
9263 {
9264         struct btrfs_fs_info *fs_info = cache->fs_info;
9265         struct btrfs_trans_handle *trans;
9266         u64 alloc_flags;
9267         int ret;
9268
9269 again:
9270         trans = btrfs_join_transaction(fs_info->extent_root);
9271         if (IS_ERR(trans))
9272                 return PTR_ERR(trans);
9273
9274         /*
9275          * we're not allowed to set block groups readonly after the dirty
9276          * block groups cache has started writing.  If it already started,
9277          * back off and let this transaction commit
9278          */
9279         mutex_lock(&fs_info->ro_block_group_mutex);
9280         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9281                 u64 transid = trans->transid;
9282
9283                 mutex_unlock(&fs_info->ro_block_group_mutex);
9284                 btrfs_end_transaction(trans);
9285
9286                 ret = btrfs_wait_for_commit(fs_info, transid);
9287                 if (ret)
9288                         return ret;
9289                 goto again;
9290         }
9291
9292         /*
9293          * if we are changing raid levels, try to allocate a corresponding
9294          * block group with the new raid level.
9295          */
9296         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9297         if (alloc_flags != cache->flags) {
9298                 ret = do_chunk_alloc(trans, alloc_flags,
9299                                      CHUNK_ALLOC_FORCE);
9300                 /*
9301                  * ENOSPC is allowed here, we may have enough space
9302                  * already allocated at the new raid level to
9303                  * carry on
9304                  */
9305                 if (ret == -ENOSPC)
9306                         ret = 0;
9307                 if (ret < 0)
9308                         goto out;
9309         }
9310
9311         ret = inc_block_group_ro(cache, 0);
9312         if (!ret)
9313                 goto out;
9314         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9315         ret = do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9316         if (ret < 0)
9317                 goto out;
9318         ret = inc_block_group_ro(cache, 0);
9319 out:
9320         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9321                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9322                 mutex_lock(&fs_info->chunk_mutex);
9323                 check_system_chunk(trans, alloc_flags);
9324                 mutex_unlock(&fs_info->chunk_mutex);
9325         }
9326         mutex_unlock(&fs_info->ro_block_group_mutex);
9327
9328         btrfs_end_transaction(trans);
9329         return ret;
9330 }
9331
9332 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
9333 {
9334         u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
9335
9336         return do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9337 }
9338
9339 /*
9340  * helper to account the unused space of all the readonly block group in the
9341  * space_info. takes mirrors into account.
9342  */
9343 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9344 {
9345         struct btrfs_block_group_cache *block_group;
9346         u64 free_bytes = 0;
9347         int factor;
9348
9349         /* It's df, we don't care if it's racy */
9350         if (list_empty(&sinfo->ro_bgs))
9351                 return 0;
9352
9353         spin_lock(&sinfo->lock);
9354         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9355                 spin_lock(&block_group->lock);
9356
9357                 if (!block_group->ro) {
9358                         spin_unlock(&block_group->lock);
9359                         continue;
9360                 }
9361
9362                 factor = btrfs_bg_type_to_factor(block_group->flags);
9363                 free_bytes += (block_group->key.offset -
9364                                btrfs_block_group_used(&block_group->item)) *
9365                                factor;
9366
9367                 spin_unlock(&block_group->lock);
9368         }
9369         spin_unlock(&sinfo->lock);
9370
9371         return free_bytes;
9372 }
9373
9374 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9375 {
9376         struct btrfs_space_info *sinfo = cache->space_info;
9377         u64 num_bytes;
9378
9379         BUG_ON(!cache->ro);
9380
9381         spin_lock(&sinfo->lock);
9382         spin_lock(&cache->lock);
9383         if (!--cache->ro) {
9384                 num_bytes = cache->key.offset - cache->reserved -
9385                             cache->pinned - cache->bytes_super -
9386                             btrfs_block_group_used(&cache->item);
9387                 sinfo->bytes_readonly -= num_bytes;
9388                 list_del_init(&cache->ro_list);
9389         }
9390         spin_unlock(&cache->lock);
9391         spin_unlock(&sinfo->lock);
9392 }
9393
9394 /*
9395  * checks to see if its even possible to relocate this block group.
9396  *
9397  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9398  * ok to go ahead and try.
9399  */
9400 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9401 {
9402         struct btrfs_root *root = fs_info->extent_root;
9403         struct btrfs_block_group_cache *block_group;
9404         struct btrfs_space_info *space_info;
9405         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9406         struct btrfs_device *device;
9407         struct btrfs_trans_handle *trans;
9408         u64 min_free;
9409         u64 dev_min = 1;
9410         u64 dev_nr = 0;
9411         u64 target;
9412         int debug;
9413         int index;
9414         int full = 0;
9415         int ret = 0;
9416
9417         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9418
9419         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9420
9421         /* odd, couldn't find the block group, leave it alone */
9422         if (!block_group) {
9423                 if (debug)
9424                         btrfs_warn(fs_info,
9425                                    "can't find block group for bytenr %llu",
9426                                    bytenr);
9427                 return -1;
9428         }
9429
9430         min_free = btrfs_block_group_used(&block_group->item);
9431
9432         /* no bytes used, we're good */
9433         if (!min_free)
9434                 goto out;
9435
9436         space_info = block_group->space_info;
9437         spin_lock(&space_info->lock);
9438
9439         full = space_info->full;
9440
9441         /*
9442          * if this is the last block group we have in this space, we can't
9443          * relocate it unless we're able to allocate a new chunk below.
9444          *
9445          * Otherwise, we need to make sure we have room in the space to handle
9446          * all of the extents from this block group.  If we can, we're good
9447          */
9448         if ((space_info->total_bytes != block_group->key.offset) &&
9449             (btrfs_space_info_used(space_info, false) + min_free <
9450              space_info->total_bytes)) {
9451                 spin_unlock(&space_info->lock);
9452                 goto out;
9453         }
9454         spin_unlock(&space_info->lock);
9455
9456         /*
9457          * ok we don't have enough space, but maybe we have free space on our
9458          * devices to allocate new chunks for relocation, so loop through our
9459          * alloc devices and guess if we have enough space.  if this block
9460          * group is going to be restriped, run checks against the target
9461          * profile instead of the current one.
9462          */
9463         ret = -1;
9464
9465         /*
9466          * index:
9467          *      0: raid10
9468          *      1: raid1
9469          *      2: dup
9470          *      3: raid0
9471          *      4: single
9472          */
9473         target = get_restripe_target(fs_info, block_group->flags);
9474         if (target) {
9475                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9476         } else {
9477                 /*
9478                  * this is just a balance, so if we were marked as full
9479                  * we know there is no space for a new chunk
9480                  */
9481                 if (full) {
9482                         if (debug)
9483                                 btrfs_warn(fs_info,
9484                                            "no space to alloc new chunk for block group %llu",
9485                                            block_group->key.objectid);
9486                         goto out;
9487                 }
9488
9489                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9490         }
9491
9492         if (index == BTRFS_RAID_RAID10) {
9493                 dev_min = 4;
9494                 /* Divide by 2 */
9495                 min_free >>= 1;
9496         } else if (index == BTRFS_RAID_RAID1) {
9497                 dev_min = 2;
9498         } else if (index == BTRFS_RAID_DUP) {
9499                 /* Multiply by 2 */
9500                 min_free <<= 1;
9501         } else if (index == BTRFS_RAID_RAID0) {
9502                 dev_min = fs_devices->rw_devices;
9503                 min_free = div64_u64(min_free, dev_min);
9504         }
9505
9506         /* We need to do this so that we can look at pending chunks */
9507         trans = btrfs_join_transaction(root);
9508         if (IS_ERR(trans)) {
9509                 ret = PTR_ERR(trans);
9510                 goto out;
9511         }
9512
9513         mutex_lock(&fs_info->chunk_mutex);
9514         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9515                 u64 dev_offset;
9516
9517                 /*
9518                  * check to make sure we can actually find a chunk with enough
9519                  * space to fit our block group in.
9520                  */
9521                 if (device->total_bytes > device->bytes_used + min_free &&
9522                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9523                         ret = find_free_dev_extent(trans, device, min_free,
9524                                                    &dev_offset, NULL);
9525                         if (!ret)
9526                                 dev_nr++;
9527
9528                         if (dev_nr >= dev_min)
9529                                 break;
9530
9531                         ret = -1;
9532                 }
9533         }
9534         if (debug && ret == -1)
9535                 btrfs_warn(fs_info,
9536                            "no space to allocate a new chunk for block group %llu",
9537                            block_group->key.objectid);
9538         mutex_unlock(&fs_info->chunk_mutex);
9539         btrfs_end_transaction(trans);
9540 out:
9541         btrfs_put_block_group(block_group);
9542         return ret;
9543 }
9544
9545 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9546                                   struct btrfs_path *path,
9547                                   struct btrfs_key *key)
9548 {
9549         struct btrfs_root *root = fs_info->extent_root;
9550         int ret = 0;
9551         struct btrfs_key found_key;
9552         struct extent_buffer *leaf;
9553         struct btrfs_block_group_item bg;
9554         u64 flags;
9555         int slot;
9556
9557         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9558         if (ret < 0)
9559                 goto out;
9560
9561         while (1) {
9562                 slot = path->slots[0];
9563                 leaf = path->nodes[0];
9564                 if (slot >= btrfs_header_nritems(leaf)) {
9565                         ret = btrfs_next_leaf(root, path);
9566                         if (ret == 0)
9567                                 continue;
9568                         if (ret < 0)
9569                                 goto out;
9570                         break;
9571                 }
9572                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9573
9574                 if (found_key.objectid >= key->objectid &&
9575                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9576                         struct extent_map_tree *em_tree;
9577                         struct extent_map *em;
9578
9579                         em_tree = &root->fs_info->mapping_tree.map_tree;
9580                         read_lock(&em_tree->lock);
9581                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9582                                                    found_key.offset);
9583                         read_unlock(&em_tree->lock);
9584                         if (!em) {
9585                                 btrfs_err(fs_info,
9586                         "logical %llu len %llu found bg but no related chunk",
9587                                           found_key.objectid, found_key.offset);
9588                                 ret = -ENOENT;
9589                         } else if (em->start != found_key.objectid ||
9590                                    em->len != found_key.offset) {
9591                                 btrfs_err(fs_info,
9592                 "block group %llu len %llu mismatch with chunk %llu len %llu",
9593                                           found_key.objectid, found_key.offset,
9594                                           em->start, em->len);
9595                                 ret = -EUCLEAN;
9596                         } else {
9597                                 read_extent_buffer(leaf, &bg,
9598                                         btrfs_item_ptr_offset(leaf, slot),
9599                                         sizeof(bg));
9600                                 flags = btrfs_block_group_flags(&bg) &
9601                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
9602
9603                                 if (flags != (em->map_lookup->type &
9604                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9605                                         btrfs_err(fs_info,
9606 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
9607                                                 found_key.objectid,
9608                                                 found_key.offset, flags,
9609                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
9610                                                  em->map_lookup->type));
9611                                         ret = -EUCLEAN;
9612                                 } else {
9613                                         ret = 0;
9614                                 }
9615                         }
9616                         free_extent_map(em);
9617                         goto out;
9618                 }
9619                 path->slots[0]++;
9620         }
9621 out:
9622         return ret;
9623 }
9624
9625 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9626 {
9627         struct btrfs_block_group_cache *block_group;
9628         u64 last = 0;
9629
9630         while (1) {
9631                 struct inode *inode;
9632
9633                 block_group = btrfs_lookup_first_block_group(info, last);
9634                 while (block_group) {
9635                         wait_block_group_cache_done(block_group);
9636                         spin_lock(&block_group->lock);
9637                         if (block_group->iref)
9638                                 break;
9639                         spin_unlock(&block_group->lock);
9640                         block_group = next_block_group(info, block_group);
9641                 }
9642                 if (!block_group) {
9643                         if (last == 0)
9644                                 break;
9645                         last = 0;
9646                         continue;
9647                 }
9648
9649                 inode = block_group->inode;
9650                 block_group->iref = 0;
9651                 block_group->inode = NULL;
9652                 spin_unlock(&block_group->lock);
9653                 ASSERT(block_group->io_ctl.inode == NULL);
9654                 iput(inode);
9655                 last = block_group->key.objectid + block_group->key.offset;
9656                 btrfs_put_block_group(block_group);
9657         }
9658 }
9659
9660 /*
9661  * Must be called only after stopping all workers, since we could have block
9662  * group caching kthreads running, and therefore they could race with us if we
9663  * freed the block groups before stopping them.
9664  */
9665 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9666 {
9667         struct btrfs_block_group_cache *block_group;
9668         struct btrfs_space_info *space_info;
9669         struct btrfs_caching_control *caching_ctl;
9670         struct rb_node *n;
9671
9672         down_write(&info->commit_root_sem);
9673         while (!list_empty(&info->caching_block_groups)) {
9674                 caching_ctl = list_entry(info->caching_block_groups.next,
9675                                          struct btrfs_caching_control, list);
9676                 list_del(&caching_ctl->list);
9677                 put_caching_control(caching_ctl);
9678         }
9679         up_write(&info->commit_root_sem);
9680
9681         spin_lock(&info->unused_bgs_lock);
9682         while (!list_empty(&info->unused_bgs)) {
9683                 block_group = list_first_entry(&info->unused_bgs,
9684                                                struct btrfs_block_group_cache,
9685                                                bg_list);
9686                 list_del_init(&block_group->bg_list);
9687                 btrfs_put_block_group(block_group);
9688         }
9689         spin_unlock(&info->unused_bgs_lock);
9690
9691         spin_lock(&info->block_group_cache_lock);
9692         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9693                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9694                                        cache_node);
9695                 rb_erase(&block_group->cache_node,
9696                          &info->block_group_cache_tree);
9697                 RB_CLEAR_NODE(&block_group->cache_node);
9698                 spin_unlock(&info->block_group_cache_lock);
9699
9700                 down_write(&block_group->space_info->groups_sem);
9701                 list_del(&block_group->list);
9702                 up_write(&block_group->space_info->groups_sem);
9703
9704                 /*
9705                  * We haven't cached this block group, which means we could
9706                  * possibly have excluded extents on this block group.
9707                  */
9708                 if (block_group->cached == BTRFS_CACHE_NO ||
9709                     block_group->cached == BTRFS_CACHE_ERROR)
9710                         free_excluded_extents(block_group);
9711
9712                 btrfs_remove_free_space_cache(block_group);
9713                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9714                 ASSERT(list_empty(&block_group->dirty_list));
9715                 ASSERT(list_empty(&block_group->io_list));
9716                 ASSERT(list_empty(&block_group->bg_list));
9717                 ASSERT(atomic_read(&block_group->count) == 1);
9718                 btrfs_put_block_group(block_group);
9719
9720                 spin_lock(&info->block_group_cache_lock);
9721         }
9722         spin_unlock(&info->block_group_cache_lock);
9723
9724         /* now that all the block groups are freed, go through and
9725          * free all the space_info structs.  This is only called during
9726          * the final stages of unmount, and so we know nobody is
9727          * using them.  We call synchronize_rcu() once before we start,
9728          * just to be on the safe side.
9729          */
9730         synchronize_rcu();
9731
9732         release_global_block_rsv(info);
9733
9734         while (!list_empty(&info->space_info)) {
9735                 int i;
9736
9737                 space_info = list_entry(info->space_info.next,
9738                                         struct btrfs_space_info,
9739                                         list);
9740
9741                 /*
9742                  * Do not hide this behind enospc_debug, this is actually
9743                  * important and indicates a real bug if this happens.
9744                  */
9745                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9746                             space_info->bytes_reserved > 0 ||
9747                             space_info->bytes_may_use > 0))
9748                         dump_space_info(info, space_info, 0, 0);
9749                 list_del(&space_info->list);
9750                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9751                         struct kobject *kobj;
9752                         kobj = space_info->block_group_kobjs[i];
9753                         space_info->block_group_kobjs[i] = NULL;
9754                         if (kobj) {
9755                                 kobject_del(kobj);
9756                                 kobject_put(kobj);
9757                         }
9758                 }
9759                 kobject_del(&space_info->kobj);
9760                 kobject_put(&space_info->kobj);
9761         }
9762         return 0;
9763 }
9764
9765 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9766 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9767 {
9768         struct btrfs_space_info *space_info;
9769         struct raid_kobject *rkobj;
9770         LIST_HEAD(list);
9771         int index;
9772         int ret = 0;
9773
9774         spin_lock(&fs_info->pending_raid_kobjs_lock);
9775         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9776         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9777
9778         list_for_each_entry(rkobj, &list, list) {
9779                 space_info = __find_space_info(fs_info, rkobj->flags);
9780                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9781
9782                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9783                                   "%s", get_raid_name(index));
9784                 if (ret) {
9785                         kobject_put(&rkobj->kobj);
9786                         break;
9787                 }
9788         }
9789         if (ret)
9790                 btrfs_warn(fs_info,
9791                            "failed to add kobject for block cache, ignoring");
9792 }
9793
9794 static void link_block_group(struct btrfs_block_group_cache *cache)
9795 {
9796         struct btrfs_space_info *space_info = cache->space_info;
9797         struct btrfs_fs_info *fs_info = cache->fs_info;
9798         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9799         bool first = false;
9800
9801         down_write(&space_info->groups_sem);
9802         if (list_empty(&space_info->block_groups[index]))
9803                 first = true;
9804         list_add_tail(&cache->list, &space_info->block_groups[index]);
9805         up_write(&space_info->groups_sem);
9806
9807         if (first) {
9808                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9809                 if (!rkobj) {
9810                         btrfs_warn(cache->fs_info,
9811                                 "couldn't alloc memory for raid level kobject");
9812                         return;
9813                 }
9814                 rkobj->flags = cache->flags;
9815                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9816
9817                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9818                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9819                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9820                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9821         }
9822 }
9823
9824 static struct btrfs_block_group_cache *
9825 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9826                                u64 start, u64 size)
9827 {
9828         struct btrfs_block_group_cache *cache;
9829
9830         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9831         if (!cache)
9832                 return NULL;
9833
9834         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9835                                         GFP_NOFS);
9836         if (!cache->free_space_ctl) {
9837                 kfree(cache);
9838                 return NULL;
9839         }
9840
9841         cache->key.objectid = start;
9842         cache->key.offset = size;
9843         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9844
9845         cache->fs_info = fs_info;
9846         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
9847         set_free_space_tree_thresholds(cache);
9848
9849         atomic_set(&cache->count, 1);
9850         spin_lock_init(&cache->lock);
9851         init_rwsem(&cache->data_rwsem);
9852         INIT_LIST_HEAD(&cache->list);
9853         INIT_LIST_HEAD(&cache->cluster_list);
9854         INIT_LIST_HEAD(&cache->bg_list);
9855         INIT_LIST_HEAD(&cache->ro_list);
9856         INIT_LIST_HEAD(&cache->dirty_list);
9857         INIT_LIST_HEAD(&cache->io_list);
9858         btrfs_init_free_space_ctl(cache);
9859         atomic_set(&cache->trimming, 0);
9860         mutex_init(&cache->free_space_lock);
9861         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
9862
9863         return cache;
9864 }
9865
9866
9867 /*
9868  * Iterate all chunks and verify that each of them has the corresponding block
9869  * group
9870  */
9871 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
9872 {
9873         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
9874         struct extent_map *em;
9875         struct btrfs_block_group_cache *bg;
9876         u64 start = 0;
9877         int ret = 0;
9878
9879         while (1) {
9880                 read_lock(&map_tree->map_tree.lock);
9881                 /*
9882                  * lookup_extent_mapping will return the first extent map
9883                  * intersecting the range, so setting @len to 1 is enough to
9884                  * get the first chunk.
9885                  */
9886                 em = lookup_extent_mapping(&map_tree->map_tree, start, 1);
9887                 read_unlock(&map_tree->map_tree.lock);
9888                 if (!em)
9889                         break;
9890
9891                 bg = btrfs_lookup_block_group(fs_info, em->start);
9892                 if (!bg) {
9893                         btrfs_err(fs_info,
9894         "chunk start=%llu len=%llu doesn't have corresponding block group",
9895                                      em->start, em->len);
9896                         ret = -EUCLEAN;
9897                         free_extent_map(em);
9898                         break;
9899                 }
9900                 if (bg->key.objectid != em->start ||
9901                     bg->key.offset != em->len ||
9902                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
9903                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9904                         btrfs_err(fs_info,
9905 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
9906                                 em->start, em->len,
9907                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
9908                                 bg->key.objectid, bg->key.offset,
9909                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
9910                         ret = -EUCLEAN;
9911                         free_extent_map(em);
9912                         btrfs_put_block_group(bg);
9913                         break;
9914                 }
9915                 start = em->start + em->len;
9916                 free_extent_map(em);
9917                 btrfs_put_block_group(bg);
9918         }
9919         return ret;
9920 }
9921
9922 int btrfs_read_block_groups(struct btrfs_fs_info *info)
9923 {
9924         struct btrfs_path *path;
9925         int ret;
9926         struct btrfs_block_group_cache *cache;
9927         struct btrfs_space_info *space_info;
9928         struct btrfs_key key;
9929         struct btrfs_key found_key;
9930         struct extent_buffer *leaf;
9931         int need_clear = 0;
9932         u64 cache_gen;
9933         u64 feature;
9934         int mixed;
9935
9936         feature = btrfs_super_incompat_flags(info->super_copy);
9937         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
9938
9939         key.objectid = 0;
9940         key.offset = 0;
9941         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9942         path = btrfs_alloc_path();
9943         if (!path)
9944                 return -ENOMEM;
9945         path->reada = READA_FORWARD;
9946
9947         cache_gen = btrfs_super_cache_generation(info->super_copy);
9948         if (btrfs_test_opt(info, SPACE_CACHE) &&
9949             btrfs_super_generation(info->super_copy) != cache_gen)
9950                 need_clear = 1;
9951         if (btrfs_test_opt(info, CLEAR_CACHE))
9952                 need_clear = 1;
9953
9954         while (1) {
9955                 ret = find_first_block_group(info, path, &key);
9956                 if (ret > 0)
9957                         break;
9958                 if (ret != 0)
9959                         goto error;
9960
9961                 leaf = path->nodes[0];
9962                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9963
9964                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
9965                                                        found_key.offset);
9966                 if (!cache) {
9967                         ret = -ENOMEM;
9968                         goto error;
9969                 }
9970
9971                 if (need_clear) {
9972                         /*
9973                          * When we mount with old space cache, we need to
9974                          * set BTRFS_DC_CLEAR and set dirty flag.
9975                          *
9976                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9977                          *    truncate the old free space cache inode and
9978                          *    setup a new one.
9979                          * b) Setting 'dirty flag' makes sure that we flush
9980                          *    the new space cache info onto disk.
9981                          */
9982                         if (btrfs_test_opt(info, SPACE_CACHE))
9983                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9984                 }
9985
9986                 read_extent_buffer(leaf, &cache->item,
9987                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9988                                    sizeof(cache->item));
9989                 cache->flags = btrfs_block_group_flags(&cache->item);
9990                 if (!mixed &&
9991                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
9992                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
9993                         btrfs_err(info,
9994 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
9995                                   cache->key.objectid);
9996                         ret = -EINVAL;
9997                         goto error;
9998                 }
9999
10000                 key.objectid = found_key.objectid + found_key.offset;
10001                 btrfs_release_path(path);
10002
10003                 /*
10004                  * We need to exclude the super stripes now so that the space
10005                  * info has super bytes accounted for, otherwise we'll think
10006                  * we have more space than we actually do.
10007                  */
10008                 ret = exclude_super_stripes(cache);
10009                 if (ret) {
10010                         /*
10011                          * We may have excluded something, so call this just in
10012                          * case.
10013                          */
10014                         free_excluded_extents(cache);
10015                         btrfs_put_block_group(cache);
10016                         goto error;
10017                 }
10018
10019                 /*
10020                  * check for two cases, either we are full, and therefore
10021                  * don't need to bother with the caching work since we won't
10022                  * find any space, or we are empty, and we can just add all
10023                  * the space in and be done with it.  This saves us _alot_ of
10024                  * time, particularly in the full case.
10025                  */
10026                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10027                         cache->last_byte_to_unpin = (u64)-1;
10028                         cache->cached = BTRFS_CACHE_FINISHED;
10029                         free_excluded_extents(cache);
10030                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10031                         cache->last_byte_to_unpin = (u64)-1;
10032                         cache->cached = BTRFS_CACHE_FINISHED;
10033                         add_new_free_space(cache, found_key.objectid,
10034                                            found_key.objectid +
10035                                            found_key.offset);
10036                         free_excluded_extents(cache);
10037                 }
10038
10039                 ret = btrfs_add_block_group_cache(info, cache);
10040                 if (ret) {
10041                         btrfs_remove_free_space_cache(cache);
10042                         btrfs_put_block_group(cache);
10043                         goto error;
10044                 }
10045
10046                 trace_btrfs_add_block_group(info, cache, 0);
10047                 update_space_info(info, cache->flags, found_key.offset,
10048                                   btrfs_block_group_used(&cache->item),
10049                                   cache->bytes_super, &space_info);
10050
10051                 cache->space_info = space_info;
10052
10053                 link_block_group(cache);
10054
10055                 set_avail_alloc_bits(info, cache->flags);
10056                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10057                         inc_block_group_ro(cache, 1);
10058                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10059                         ASSERT(list_empty(&cache->bg_list));
10060                         btrfs_mark_bg_unused(cache);
10061                 }
10062         }
10063
10064         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10065                 if (!(get_alloc_profile(info, space_info->flags) &
10066                       (BTRFS_BLOCK_GROUP_RAID10 |
10067                        BTRFS_BLOCK_GROUP_RAID1 |
10068                        BTRFS_BLOCK_GROUP_RAID5 |
10069                        BTRFS_BLOCK_GROUP_RAID6 |
10070                        BTRFS_BLOCK_GROUP_DUP)))
10071                         continue;
10072                 /*
10073                  * avoid allocating from un-mirrored block group if there are
10074                  * mirrored block groups.
10075                  */
10076                 list_for_each_entry(cache,
10077                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10078                                 list)
10079                         inc_block_group_ro(cache, 1);
10080                 list_for_each_entry(cache,
10081                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10082                                 list)
10083                         inc_block_group_ro(cache, 1);
10084         }
10085
10086         btrfs_add_raid_kobjects(info);
10087         init_global_block_rsv(info);
10088         ret = check_chunk_block_group_mappings(info);
10089 error:
10090         btrfs_free_path(path);
10091         return ret;
10092 }
10093
10094 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10095 {
10096         struct btrfs_fs_info *fs_info = trans->fs_info;
10097         struct btrfs_block_group_cache *block_group;
10098         struct btrfs_root *extent_root = fs_info->extent_root;
10099         struct btrfs_block_group_item item;
10100         struct btrfs_key key;
10101         int ret = 0;
10102
10103         if (!trans->can_flush_pending_bgs)
10104                 return;
10105
10106         while (!list_empty(&trans->new_bgs)) {
10107                 block_group = list_first_entry(&trans->new_bgs,
10108                                                struct btrfs_block_group_cache,
10109                                                bg_list);
10110                 if (ret)
10111                         goto next;
10112
10113                 spin_lock(&block_group->lock);
10114                 memcpy(&item, &block_group->item, sizeof(item));
10115                 memcpy(&key, &block_group->key, sizeof(key));
10116                 spin_unlock(&block_group->lock);
10117
10118                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10119                                         sizeof(item));
10120                 if (ret)
10121                         btrfs_abort_transaction(trans, ret);
10122                 ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
10123                 if (ret)
10124                         btrfs_abort_transaction(trans, ret);
10125                 add_block_group_free_space(trans, block_group);
10126                 /* already aborted the transaction if it failed. */
10127 next:
10128                 list_del_init(&block_group->bg_list);
10129         }
10130         btrfs_trans_release_chunk_metadata(trans);
10131 }
10132
10133 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
10134                            u64 type, u64 chunk_offset, u64 size)
10135 {
10136         struct btrfs_fs_info *fs_info = trans->fs_info;
10137         struct btrfs_block_group_cache *cache;
10138         int ret;
10139
10140         btrfs_set_log_full_commit(fs_info, trans);
10141
10142         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10143         if (!cache)
10144                 return -ENOMEM;
10145
10146         btrfs_set_block_group_used(&cache->item, bytes_used);
10147         btrfs_set_block_group_chunk_objectid(&cache->item,
10148                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10149         btrfs_set_block_group_flags(&cache->item, type);
10150
10151         cache->flags = type;
10152         cache->last_byte_to_unpin = (u64)-1;
10153         cache->cached = BTRFS_CACHE_FINISHED;
10154         cache->needs_free_space = 1;
10155         ret = exclude_super_stripes(cache);
10156         if (ret) {
10157                 /*
10158                  * We may have excluded something, so call this just in
10159                  * case.
10160                  */
10161                 free_excluded_extents(cache);
10162                 btrfs_put_block_group(cache);
10163                 return ret;
10164         }
10165
10166         add_new_free_space(cache, chunk_offset, chunk_offset + size);
10167
10168         free_excluded_extents(cache);
10169
10170 #ifdef CONFIG_BTRFS_DEBUG
10171         if (btrfs_should_fragment_free_space(cache)) {
10172                 u64 new_bytes_used = size - bytes_used;
10173
10174                 bytes_used += new_bytes_used >> 1;
10175                 fragment_free_space(cache);
10176         }
10177 #endif
10178         /*
10179          * Ensure the corresponding space_info object is created and
10180          * assigned to our block group. We want our bg to be added to the rbtree
10181          * with its ->space_info set.
10182          */
10183         cache->space_info = __find_space_info(fs_info, cache->flags);
10184         ASSERT(cache->space_info);
10185
10186         ret = btrfs_add_block_group_cache(fs_info, cache);
10187         if (ret) {
10188                 btrfs_remove_free_space_cache(cache);
10189                 btrfs_put_block_group(cache);
10190                 return ret;
10191         }
10192
10193         /*
10194          * Now that our block group has its ->space_info set and is inserted in
10195          * the rbtree, update the space info's counters.
10196          */
10197         trace_btrfs_add_block_group(fs_info, cache, 1);
10198         update_space_info(fs_info, cache->flags, size, bytes_used,
10199                                 cache->bytes_super, &cache->space_info);
10200         update_global_block_rsv(fs_info);
10201
10202         link_block_group(cache);
10203
10204         list_add_tail(&cache->bg_list, &trans->new_bgs);
10205
10206         set_avail_alloc_bits(fs_info, type);
10207         return 0;
10208 }
10209
10210 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10211 {
10212         u64 extra_flags = chunk_to_extended(flags) &
10213                                 BTRFS_EXTENDED_PROFILE_MASK;
10214
10215         write_seqlock(&fs_info->profiles_lock);
10216         if (flags & BTRFS_BLOCK_GROUP_DATA)
10217                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10218         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10219                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10220         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10221                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10222         write_sequnlock(&fs_info->profiles_lock);
10223 }
10224
10225 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10226                              u64 group_start, struct extent_map *em)
10227 {
10228         struct btrfs_fs_info *fs_info = trans->fs_info;
10229         struct btrfs_root *root = fs_info->extent_root;
10230         struct btrfs_path *path;
10231         struct btrfs_block_group_cache *block_group;
10232         struct btrfs_free_cluster *cluster;
10233         struct btrfs_root *tree_root = fs_info->tree_root;
10234         struct btrfs_key key;
10235         struct inode *inode;
10236         struct kobject *kobj = NULL;
10237         int ret;
10238         int index;
10239         int factor;
10240         struct btrfs_caching_control *caching_ctl = NULL;
10241         bool remove_em;
10242
10243         block_group = btrfs_lookup_block_group(fs_info, group_start);
10244         BUG_ON(!block_group);
10245         BUG_ON(!block_group->ro);
10246
10247         trace_btrfs_remove_block_group(block_group);
10248         /*
10249          * Free the reserved super bytes from this block group before
10250          * remove it.
10251          */
10252         free_excluded_extents(block_group);
10253         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10254                                   block_group->key.offset);
10255
10256         memcpy(&key, &block_group->key, sizeof(key));
10257         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10258         factor = btrfs_bg_type_to_factor(block_group->flags);
10259
10260         /* make sure this block group isn't part of an allocation cluster */
10261         cluster = &fs_info->data_alloc_cluster;
10262         spin_lock(&cluster->refill_lock);
10263         btrfs_return_cluster_to_free_space(block_group, cluster);
10264         spin_unlock(&cluster->refill_lock);
10265
10266         /*
10267          * make sure this block group isn't part of a metadata
10268          * allocation cluster
10269          */
10270         cluster = &fs_info->meta_alloc_cluster;
10271         spin_lock(&cluster->refill_lock);
10272         btrfs_return_cluster_to_free_space(block_group, cluster);
10273         spin_unlock(&cluster->refill_lock);
10274
10275         path = btrfs_alloc_path();
10276         if (!path) {
10277                 ret = -ENOMEM;
10278                 goto out;
10279         }
10280
10281         /*
10282          * get the inode first so any iput calls done for the io_list
10283          * aren't the final iput (no unlinks allowed now)
10284          */
10285         inode = lookup_free_space_inode(fs_info, block_group, path);
10286
10287         mutex_lock(&trans->transaction->cache_write_mutex);
10288         /*
10289          * make sure our free spache cache IO is done before remove the
10290          * free space inode
10291          */
10292         spin_lock(&trans->transaction->dirty_bgs_lock);
10293         if (!list_empty(&block_group->io_list)) {
10294                 list_del_init(&block_group->io_list);
10295
10296                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10297
10298                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10299                 btrfs_wait_cache_io(trans, block_group, path);
10300                 btrfs_put_block_group(block_group);
10301                 spin_lock(&trans->transaction->dirty_bgs_lock);
10302         }
10303
10304         if (!list_empty(&block_group->dirty_list)) {
10305                 list_del_init(&block_group->dirty_list);
10306                 btrfs_put_block_group(block_group);
10307         }
10308         spin_unlock(&trans->transaction->dirty_bgs_lock);
10309         mutex_unlock(&trans->transaction->cache_write_mutex);
10310
10311         if (!IS_ERR(inode)) {
10312                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10313                 if (ret) {
10314                         btrfs_add_delayed_iput(inode);
10315                         goto out;
10316                 }
10317                 clear_nlink(inode);
10318                 /* One for the block groups ref */
10319                 spin_lock(&block_group->lock);
10320                 if (block_group->iref) {
10321                         block_group->iref = 0;
10322                         block_group->inode = NULL;
10323                         spin_unlock(&block_group->lock);
10324                         iput(inode);
10325                 } else {
10326                         spin_unlock(&block_group->lock);
10327                 }
10328                 /* One for our lookup ref */
10329                 btrfs_add_delayed_iput(inode);
10330         }
10331
10332         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10333         key.offset = block_group->key.objectid;
10334         key.type = 0;
10335
10336         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10337         if (ret < 0)
10338                 goto out;
10339         if (ret > 0)
10340                 btrfs_release_path(path);
10341         if (ret == 0) {
10342                 ret = btrfs_del_item(trans, tree_root, path);
10343                 if (ret)
10344                         goto out;
10345                 btrfs_release_path(path);
10346         }
10347
10348         spin_lock(&fs_info->block_group_cache_lock);
10349         rb_erase(&block_group->cache_node,
10350                  &fs_info->block_group_cache_tree);
10351         RB_CLEAR_NODE(&block_group->cache_node);
10352
10353         if (fs_info->first_logical_byte == block_group->key.objectid)
10354                 fs_info->first_logical_byte = (u64)-1;
10355         spin_unlock(&fs_info->block_group_cache_lock);
10356
10357         down_write(&block_group->space_info->groups_sem);
10358         /*
10359          * we must use list_del_init so people can check to see if they
10360          * are still on the list after taking the semaphore
10361          */
10362         list_del_init(&block_group->list);
10363         if (list_empty(&block_group->space_info->block_groups[index])) {
10364                 kobj = block_group->space_info->block_group_kobjs[index];
10365                 block_group->space_info->block_group_kobjs[index] = NULL;
10366                 clear_avail_alloc_bits(fs_info, block_group->flags);
10367         }
10368         up_write(&block_group->space_info->groups_sem);
10369         if (kobj) {
10370                 kobject_del(kobj);
10371                 kobject_put(kobj);
10372         }
10373
10374         if (block_group->has_caching_ctl)
10375                 caching_ctl = get_caching_control(block_group);
10376         if (block_group->cached == BTRFS_CACHE_STARTED)
10377                 wait_block_group_cache_done(block_group);
10378         if (block_group->has_caching_ctl) {
10379                 down_write(&fs_info->commit_root_sem);
10380                 if (!caching_ctl) {
10381                         struct btrfs_caching_control *ctl;
10382
10383                         list_for_each_entry(ctl,
10384                                     &fs_info->caching_block_groups, list)
10385                                 if (ctl->block_group == block_group) {
10386                                         caching_ctl = ctl;
10387                                         refcount_inc(&caching_ctl->count);
10388                                         break;
10389                                 }
10390                 }
10391                 if (caching_ctl)
10392                         list_del_init(&caching_ctl->list);
10393                 up_write(&fs_info->commit_root_sem);
10394                 if (caching_ctl) {
10395                         /* Once for the caching bgs list and once for us. */
10396                         put_caching_control(caching_ctl);
10397                         put_caching_control(caching_ctl);
10398                 }
10399         }
10400
10401         spin_lock(&trans->transaction->dirty_bgs_lock);
10402         if (!list_empty(&block_group->dirty_list)) {
10403                 WARN_ON(1);
10404         }
10405         if (!list_empty(&block_group->io_list)) {
10406                 WARN_ON(1);
10407         }
10408         spin_unlock(&trans->transaction->dirty_bgs_lock);
10409         btrfs_remove_free_space_cache(block_group);
10410
10411         spin_lock(&block_group->space_info->lock);
10412         list_del_init(&block_group->ro_list);
10413
10414         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10415                 WARN_ON(block_group->space_info->total_bytes
10416                         < block_group->key.offset);
10417                 WARN_ON(block_group->space_info->bytes_readonly
10418                         < block_group->key.offset);
10419                 WARN_ON(block_group->space_info->disk_total
10420                         < block_group->key.offset * factor);
10421         }
10422         block_group->space_info->total_bytes -= block_group->key.offset;
10423         block_group->space_info->bytes_readonly -= block_group->key.offset;
10424         block_group->space_info->disk_total -= block_group->key.offset * factor;
10425
10426         spin_unlock(&block_group->space_info->lock);
10427
10428         memcpy(&key, &block_group->key, sizeof(key));
10429
10430         mutex_lock(&fs_info->chunk_mutex);
10431         if (!list_empty(&em->list)) {
10432                 /* We're in the transaction->pending_chunks list. */
10433                 free_extent_map(em);
10434         }
10435         spin_lock(&block_group->lock);
10436         block_group->removed = 1;
10437         /*
10438          * At this point trimming can't start on this block group, because we
10439          * removed the block group from the tree fs_info->block_group_cache_tree
10440          * so no one can't find it anymore and even if someone already got this
10441          * block group before we removed it from the rbtree, they have already
10442          * incremented block_group->trimming - if they didn't, they won't find
10443          * any free space entries because we already removed them all when we
10444          * called btrfs_remove_free_space_cache().
10445          *
10446          * And we must not remove the extent map from the fs_info->mapping_tree
10447          * to prevent the same logical address range and physical device space
10448          * ranges from being reused for a new block group. This is because our
10449          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10450          * completely transactionless, so while it is trimming a range the
10451          * currently running transaction might finish and a new one start,
10452          * allowing for new block groups to be created that can reuse the same
10453          * physical device locations unless we take this special care.
10454          *
10455          * There may also be an implicit trim operation if the file system
10456          * is mounted with -odiscard. The same protections must remain
10457          * in place until the extents have been discarded completely when
10458          * the transaction commit has completed.
10459          */
10460         remove_em = (atomic_read(&block_group->trimming) == 0);
10461         /*
10462          * Make sure a trimmer task always sees the em in the pinned_chunks list
10463          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10464          * before checking block_group->removed).
10465          */
10466         if (!remove_em) {
10467                 /*
10468                  * Our em might be in trans->transaction->pending_chunks which
10469                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10470                  * and so is the fs_info->pinned_chunks list.
10471                  *
10472                  * So at this point we must be holding the chunk_mutex to avoid
10473                  * any races with chunk allocation (more specifically at
10474                  * volumes.c:contains_pending_extent()), to ensure it always
10475                  * sees the em, either in the pending_chunks list or in the
10476                  * pinned_chunks list.
10477                  */
10478                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10479         }
10480         spin_unlock(&block_group->lock);
10481
10482         if (remove_em) {
10483                 struct extent_map_tree *em_tree;
10484
10485                 em_tree = &fs_info->mapping_tree.map_tree;
10486                 write_lock(&em_tree->lock);
10487                 /*
10488                  * The em might be in the pending_chunks list, so make sure the
10489                  * chunk mutex is locked, since remove_extent_mapping() will
10490                  * delete us from that list.
10491                  */
10492                 remove_extent_mapping(em_tree, em);
10493                 write_unlock(&em_tree->lock);
10494                 /* once for the tree */
10495                 free_extent_map(em);
10496         }
10497
10498         mutex_unlock(&fs_info->chunk_mutex);
10499
10500         ret = remove_block_group_free_space(trans, block_group);
10501         if (ret)
10502                 goto out;
10503
10504         btrfs_put_block_group(block_group);
10505         btrfs_put_block_group(block_group);
10506
10507         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10508         if (ret > 0)
10509                 ret = -EIO;
10510         if (ret < 0)
10511                 goto out;
10512
10513         ret = btrfs_del_item(trans, root, path);
10514 out:
10515         btrfs_free_path(path);
10516         return ret;
10517 }
10518
10519 struct btrfs_trans_handle *
10520 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10521                                      const u64 chunk_offset)
10522 {
10523         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10524         struct extent_map *em;
10525         struct map_lookup *map;
10526         unsigned int num_items;
10527
10528         read_lock(&em_tree->lock);
10529         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10530         read_unlock(&em_tree->lock);
10531         ASSERT(em && em->start == chunk_offset);
10532
10533         /*
10534          * We need to reserve 3 + N units from the metadata space info in order
10535          * to remove a block group (done at btrfs_remove_chunk() and at
10536          * btrfs_remove_block_group()), which are used for:
10537          *
10538          * 1 unit for adding the free space inode's orphan (located in the tree
10539          * of tree roots).
10540          * 1 unit for deleting the block group item (located in the extent
10541          * tree).
10542          * 1 unit for deleting the free space item (located in tree of tree
10543          * roots).
10544          * N units for deleting N device extent items corresponding to each
10545          * stripe (located in the device tree).
10546          *
10547          * In order to remove a block group we also need to reserve units in the
10548          * system space info in order to update the chunk tree (update one or
10549          * more device items and remove one chunk item), but this is done at
10550          * btrfs_remove_chunk() through a call to check_system_chunk().
10551          */
10552         map = em->map_lookup;
10553         num_items = 3 + map->num_stripes;
10554         free_extent_map(em);
10555
10556         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10557                                                            num_items, 1);
10558 }
10559
10560 /*
10561  * Process the unused_bgs list and remove any that don't have any allocated
10562  * space inside of them.
10563  */
10564 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10565 {
10566         struct btrfs_block_group_cache *block_group;
10567         struct btrfs_space_info *space_info;
10568         struct btrfs_trans_handle *trans;
10569         int ret = 0;
10570
10571         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10572                 return;
10573
10574         spin_lock(&fs_info->unused_bgs_lock);
10575         while (!list_empty(&fs_info->unused_bgs)) {
10576                 u64 start, end;
10577                 int trimming;
10578
10579                 block_group = list_first_entry(&fs_info->unused_bgs,
10580                                                struct btrfs_block_group_cache,
10581                                                bg_list);
10582                 list_del_init(&block_group->bg_list);
10583
10584                 space_info = block_group->space_info;
10585
10586                 if (ret || btrfs_mixed_space_info(space_info)) {
10587                         btrfs_put_block_group(block_group);
10588                         continue;
10589                 }
10590                 spin_unlock(&fs_info->unused_bgs_lock);
10591
10592                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10593
10594                 /* Don't want to race with allocators so take the groups_sem */
10595                 down_write(&space_info->groups_sem);
10596                 spin_lock(&block_group->lock);
10597                 if (block_group->reserved || block_group->pinned ||
10598                     btrfs_block_group_used(&block_group->item) ||
10599                     block_group->ro ||
10600                     list_is_singular(&block_group->list)) {
10601                         /*
10602                          * We want to bail if we made new allocations or have
10603                          * outstanding allocations in this block group.  We do
10604                          * the ro check in case balance is currently acting on
10605                          * this block group.
10606                          */
10607                         trace_btrfs_skip_unused_block_group(block_group);
10608                         spin_unlock(&block_group->lock);
10609                         up_write(&space_info->groups_sem);
10610                         goto next;
10611                 }
10612                 spin_unlock(&block_group->lock);
10613
10614                 /* We don't want to force the issue, only flip if it's ok. */
10615                 ret = inc_block_group_ro(block_group, 0);
10616                 up_write(&space_info->groups_sem);
10617                 if (ret < 0) {
10618                         ret = 0;
10619                         goto next;
10620                 }
10621
10622                 /*
10623                  * Want to do this before we do anything else so we can recover
10624                  * properly if we fail to join the transaction.
10625                  */
10626                 trans = btrfs_start_trans_remove_block_group(fs_info,
10627                                                      block_group->key.objectid);
10628                 if (IS_ERR(trans)) {
10629                         btrfs_dec_block_group_ro(block_group);
10630                         ret = PTR_ERR(trans);
10631                         goto next;
10632                 }
10633
10634                 /*
10635                  * We could have pending pinned extents for this block group,
10636                  * just delete them, we don't care about them anymore.
10637                  */
10638                 start = block_group->key.objectid;
10639                 end = start + block_group->key.offset - 1;
10640                 /*
10641                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10642                  * btrfs_finish_extent_commit(). If we are at transaction N,
10643                  * another task might be running finish_extent_commit() for the
10644                  * previous transaction N - 1, and have seen a range belonging
10645                  * to the block group in freed_extents[] before we were able to
10646                  * clear the whole block group range from freed_extents[]. This
10647                  * means that task can lookup for the block group after we
10648                  * unpinned it from freed_extents[] and removed it, leading to
10649                  * a BUG_ON() at btrfs_unpin_extent_range().
10650                  */
10651                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10652                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10653                                   EXTENT_DIRTY);
10654                 if (ret) {
10655                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10656                         btrfs_dec_block_group_ro(block_group);
10657                         goto end_trans;
10658                 }
10659                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10660                                   EXTENT_DIRTY);
10661                 if (ret) {
10662                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10663                         btrfs_dec_block_group_ro(block_group);
10664                         goto end_trans;
10665                 }
10666                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10667
10668                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10669                 spin_lock(&space_info->lock);
10670                 spin_lock(&block_group->lock);
10671
10672                 space_info->bytes_pinned -= block_group->pinned;
10673                 space_info->bytes_readonly += block_group->pinned;
10674                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
10675                                    -block_group->pinned,
10676                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
10677                 block_group->pinned = 0;
10678
10679                 spin_unlock(&block_group->lock);
10680                 spin_unlock(&space_info->lock);
10681
10682                 /* DISCARD can flip during remount */
10683                 trimming = btrfs_test_opt(fs_info, DISCARD);
10684
10685                 /* Implicit trim during transaction commit. */
10686                 if (trimming)
10687                         btrfs_get_block_group_trimming(block_group);
10688
10689                 /*
10690                  * Btrfs_remove_chunk will abort the transaction if things go
10691                  * horribly wrong.
10692                  */
10693                 ret = btrfs_remove_chunk(trans, block_group->key.objectid);
10694
10695                 if (ret) {
10696                         if (trimming)
10697                                 btrfs_put_block_group_trimming(block_group);
10698                         goto end_trans;
10699                 }
10700
10701                 /*
10702                  * If we're not mounted with -odiscard, we can just forget
10703                  * about this block group. Otherwise we'll need to wait
10704                  * until transaction commit to do the actual discard.
10705                  */
10706                 if (trimming) {
10707                         spin_lock(&fs_info->unused_bgs_lock);
10708                         /*
10709                          * A concurrent scrub might have added us to the list
10710                          * fs_info->unused_bgs, so use a list_move operation
10711                          * to add the block group to the deleted_bgs list.
10712                          */
10713                         list_move(&block_group->bg_list,
10714                                   &trans->transaction->deleted_bgs);
10715                         spin_unlock(&fs_info->unused_bgs_lock);
10716                         btrfs_get_block_group(block_group);
10717                 }
10718 end_trans:
10719                 btrfs_end_transaction(trans);
10720 next:
10721                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10722                 btrfs_put_block_group(block_group);
10723                 spin_lock(&fs_info->unused_bgs_lock);
10724         }
10725         spin_unlock(&fs_info->unused_bgs_lock);
10726 }
10727
10728 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10729 {
10730         struct btrfs_super_block *disk_super;
10731         u64 features;
10732         u64 flags;
10733         int mixed = 0;
10734         int ret;
10735
10736         disk_super = fs_info->super_copy;
10737         if (!btrfs_super_root(disk_super))
10738                 return -EINVAL;
10739
10740         features = btrfs_super_incompat_flags(disk_super);
10741         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10742                 mixed = 1;
10743
10744         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10745         ret = create_space_info(fs_info, flags);
10746         if (ret)
10747                 goto out;
10748
10749         if (mixed) {
10750                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10751                 ret = create_space_info(fs_info, flags);
10752         } else {
10753                 flags = BTRFS_BLOCK_GROUP_METADATA;
10754                 ret = create_space_info(fs_info, flags);
10755                 if (ret)
10756                         goto out;
10757
10758                 flags = BTRFS_BLOCK_GROUP_DATA;
10759                 ret = create_space_info(fs_info, flags);
10760         }
10761 out:
10762         return ret;
10763 }
10764
10765 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10766                                    u64 start, u64 end)
10767 {
10768         return unpin_extent_range(fs_info, start, end, false);
10769 }
10770
10771 /*
10772  * It used to be that old block groups would be left around forever.
10773  * Iterating over them would be enough to trim unused space.  Since we
10774  * now automatically remove them, we also need to iterate over unallocated
10775  * space.
10776  *
10777  * We don't want a transaction for this since the discard may take a
10778  * substantial amount of time.  We don't require that a transaction be
10779  * running, but we do need to take a running transaction into account
10780  * to ensure that we're not discarding chunks that were released or
10781  * allocated in the current transaction.
10782  *
10783  * Holding the chunks lock will prevent other threads from allocating
10784  * or releasing chunks, but it won't prevent a running transaction
10785  * from committing and releasing the memory that the pending chunks
10786  * list head uses.  For that, we need to take a reference to the
10787  * transaction and hold the commit root sem.  We only need to hold
10788  * it while performing the free space search since we have already
10789  * held back allocations.
10790  */
10791 static int btrfs_trim_free_extents(struct btrfs_device *device,
10792                                    u64 minlen, u64 *trimmed)
10793 {
10794         u64 start = 0, len = 0;
10795         int ret;
10796
10797         *trimmed = 0;
10798
10799         /* Discard not supported = nothing to do. */
10800         if (!blk_queue_discard(bdev_get_queue(device->bdev)))
10801                 return 0;
10802
10803         /* Not writeable = nothing to do. */
10804         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10805                 return 0;
10806
10807         /* No free space = nothing to do. */
10808         if (device->total_bytes <= device->bytes_used)
10809                 return 0;
10810
10811         ret = 0;
10812
10813         while (1) {
10814                 struct btrfs_fs_info *fs_info = device->fs_info;
10815                 struct btrfs_transaction *trans;
10816                 u64 bytes;
10817
10818                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10819                 if (ret)
10820                         break;
10821
10822                 ret = down_read_killable(&fs_info->commit_root_sem);
10823                 if (ret) {
10824                         mutex_unlock(&fs_info->chunk_mutex);
10825                         break;
10826                 }
10827
10828                 spin_lock(&fs_info->trans_lock);
10829                 trans = fs_info->running_transaction;
10830                 if (trans)
10831                         refcount_inc(&trans->use_count);
10832                 spin_unlock(&fs_info->trans_lock);
10833
10834                 if (!trans)
10835                         up_read(&fs_info->commit_root_sem);
10836
10837                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10838                                                  &start, &len);
10839                 if (trans) {
10840                         up_read(&fs_info->commit_root_sem);
10841                         btrfs_put_transaction(trans);
10842                 }
10843
10844                 if (ret) {
10845                         mutex_unlock(&fs_info->chunk_mutex);
10846                         if (ret == -ENOSPC)
10847                                 ret = 0;
10848                         break;
10849                 }
10850
10851                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10852                 mutex_unlock(&fs_info->chunk_mutex);
10853
10854                 if (ret)
10855                         break;
10856
10857                 start += len;
10858                 *trimmed += bytes;
10859
10860                 if (fatal_signal_pending(current)) {
10861                         ret = -ERESTARTSYS;
10862                         break;
10863                 }
10864
10865                 cond_resched();
10866         }
10867
10868         return ret;
10869 }
10870
10871 /*
10872  * Trim the whole filesystem by:
10873  * 1) trimming the free space in each block group
10874  * 2) trimming the unallocated space on each device
10875  *
10876  * This will also continue trimming even if a block group or device encounters
10877  * an error.  The return value will be the last error, or 0 if nothing bad
10878  * happens.
10879  */
10880 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10881 {
10882         struct btrfs_block_group_cache *cache = NULL;
10883         struct btrfs_device *device;
10884         struct list_head *devices;
10885         u64 group_trimmed;
10886         u64 start;
10887         u64 end;
10888         u64 trimmed = 0;
10889         u64 bg_failed = 0;
10890         u64 dev_failed = 0;
10891         int bg_ret = 0;
10892         int dev_ret = 0;
10893         int ret = 0;
10894
10895         cache = btrfs_lookup_first_block_group(fs_info, range->start);
10896         for (; cache; cache = next_block_group(fs_info, cache)) {
10897                 if (cache->key.objectid >= (range->start + range->len)) {
10898                         btrfs_put_block_group(cache);
10899                         break;
10900                 }
10901
10902                 start = max(range->start, cache->key.objectid);
10903                 end = min(range->start + range->len,
10904                                 cache->key.objectid + cache->key.offset);
10905
10906                 if (end - start >= range->minlen) {
10907                         if (!block_group_cache_done(cache)) {
10908                                 ret = cache_block_group(cache, 0);
10909                                 if (ret) {
10910                                         bg_failed++;
10911                                         bg_ret = ret;
10912                                         continue;
10913                                 }
10914                                 ret = wait_block_group_cache_done(cache);
10915                                 if (ret) {
10916                                         bg_failed++;
10917                                         bg_ret = ret;
10918                                         continue;
10919                                 }
10920                         }
10921                         ret = btrfs_trim_block_group(cache,
10922                                                      &group_trimmed,
10923                                                      start,
10924                                                      end,
10925                                                      range->minlen);
10926
10927                         trimmed += group_trimmed;
10928                         if (ret) {
10929                                 bg_failed++;
10930                                 bg_ret = ret;
10931                                 continue;
10932                         }
10933                 }
10934         }
10935
10936         if (bg_failed)
10937                 btrfs_warn(fs_info,
10938                         "failed to trim %llu block group(s), last error %d",
10939                         bg_failed, bg_ret);
10940         mutex_lock(&fs_info->fs_devices->device_list_mutex);
10941         devices = &fs_info->fs_devices->devices;
10942         list_for_each_entry(device, devices, dev_list) {
10943                 ret = btrfs_trim_free_extents(device, range->minlen,
10944                                               &group_trimmed);
10945                 if (ret) {
10946                         dev_failed++;
10947                         dev_ret = ret;
10948                         break;
10949                 }
10950
10951                 trimmed += group_trimmed;
10952         }
10953         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
10954
10955         if (dev_failed)
10956                 btrfs_warn(fs_info,
10957                         "failed to trim %llu device(s), last error %d",
10958                         dev_failed, dev_ret);
10959         range->len = trimmed;
10960         if (bg_ret)
10961                 return bg_ret;
10962         return dev_ret;
10963 }
10964
10965 /*
10966  * btrfs_{start,end}_write_no_snapshotting() are similar to
10967  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10968  * data into the page cache through nocow before the subvolume is snapshoted,
10969  * but flush the data into disk after the snapshot creation, or to prevent
10970  * operations while snapshotting is ongoing and that cause the snapshot to be
10971  * inconsistent (writes followed by expanding truncates for example).
10972  */
10973 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
10974 {
10975         percpu_counter_dec(&root->subv_writers->counter);
10976         cond_wake_up(&root->subv_writers->wait);
10977 }
10978
10979 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
10980 {
10981         if (atomic_read(&root->will_be_snapshotted))
10982                 return 0;
10983
10984         percpu_counter_inc(&root->subv_writers->counter);
10985         /*
10986          * Make sure counter is updated before we check for snapshot creation.
10987          */
10988         smp_mb();
10989         if (atomic_read(&root->will_be_snapshotted)) {
10990                 btrfs_end_write_no_snapshotting(root);
10991                 return 0;
10992         }
10993         return 1;
10994 }
10995
10996 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
10997 {
10998         while (true) {
10999                 int ret;
11000
11001                 ret = btrfs_start_write_no_snapshotting(root);
11002                 if (ret)
11003                         break;
11004                 wait_var_event(&root->will_be_snapshotted,
11005                                !atomic_read(&root->will_be_snapshotted));
11006         }
11007 }
11008
11009 void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
11010 {
11011         struct btrfs_fs_info *fs_info = bg->fs_info;
11012
11013         spin_lock(&fs_info->unused_bgs_lock);
11014         if (list_empty(&bg->bg_list)) {
11015                 btrfs_get_block_group(bg);
11016                 trace_btrfs_add_unused_block_group(bg);
11017                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
11018         }
11019         spin_unlock(&fs_info->unused_bgs_lock);
11020 }