fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "math.h"
  37 #include "sysfs.h"
  38 #include "qgroup.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_trans_handle *trans,
  78                               struct btrfs_root *root, u64 bytenr,
  79                               u64 num_bytes, int alloc);
  80 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  81                                 struct btrfs_root *root,
  82                                 u64 bytenr, u64 num_bytes, u64 parent,
  83                                 u64 root_objectid, u64 owner_objectid,
  84                                 u64 owner_offset, int refs_to_drop,
  85                                 struct btrfs_delayed_extent_op *extra_op,
  86                                 int no_quota);
  87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  88                                     struct extent_buffer *leaf,
  89                                     struct btrfs_extent_item *ei);
  90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  91                                       struct btrfs_root *root,
  92                                       u64 parent, u64 root_objectid,
  93                                       u64 flags, u64 owner, u64 offset,
  94                                       struct btrfs_key *ins, int ref_mod);
  95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  96                                      struct btrfs_root *root,
  97                                      u64 parent, u64 root_objectid,
  98                                      u64 flags, struct btrfs_disk_key *key,
  99                                      int level, struct btrfs_key *ins,
 100                                      int no_quota);
 101 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 102                           struct btrfs_root *extent_root, u64 flags,
 103                           int force);
 104 static int find_next_key(struct btrfs_path *path, int level,
 105                          struct btrfs_key *key);
 106 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 107                             int dump_block_groups);
 108 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 109                                        u64 num_bytes, int reserve,
 110                                        int delalloc);
 111 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 112                                u64 num_bytes);
 113 int btrfs_pin_extent(struct btrfs_root *root,
 114                      u64 bytenr, u64 num_bytes, int reserved);
 115
 116 static noinline int
 117 block_group_cache_done(struct btrfs_block_group_cache *cache)
 118 {
 119         smp_mb();
 120         return cache->cached == BTRFS_CACHE_FINISHED ||
 121                 cache->cached == BTRFS_CACHE_ERROR;
 122 }
 123
 124 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 125 {
 126         return (cache->flags & bits) == bits;
 127 }
 128
 129 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         atomic_inc(&cache->count);
 132 }
 133
 134 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 135 {
 136         if (atomic_dec_and_test(&cache->count)) {
 137                 WARN_ON(cache->pinned > 0);
 138                 WARN_ON(cache->reserved > 0);
 139                 kfree(cache->free_space_ctl);
 140                 kfree(cache);
 141         }
 142 }
 143
 144 /*
 145  * this adds the block group to the fs_info rb tree for the block group
 146  * cache
 147  */
 148 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 149                                 struct btrfs_block_group_cache *block_group)
 150 {
 151         struct rb_node **p;
 152         struct rb_node *parent = NULL;
 153         struct btrfs_block_group_cache *cache;
 154
 155         spin_lock(&info->block_group_cache_lock);
 156         p = &info->block_group_cache_tree.rb_node;
 157
 158         while (*p) {
 159                 parent = *p;
 160                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 161                                  cache_node);
 162                 if (block_group->key.objectid < cache->key.objectid) {
 163                         p = &(*p)->rb_left;
 164                 } else if (block_group->key.objectid > cache->key.objectid) {
 165                         p = &(*p)->rb_right;
 166                 } else {
 167                         spin_unlock(&info->block_group_cache_lock);
 168                         return -EEXIST;
 169                 }
 170         }
 171
 172         rb_link_node(&block_group->cache_node, parent, p);
 173         rb_insert_color(&block_group->cache_node,
 174                         &info->block_group_cache_tree);
 175
 176         if (info->first_logical_byte > block_group->key.objectid)
 177                 info->first_logical_byte = block_group->key.objectid;
 178
 179         spin_unlock(&info->block_group_cache_lock);
 180
 181         return 0;
 182 }
 183
 184 /*
 185  * This will return the block group at or after bytenr if contains is 0, else
 186  * it will return the block group that contains the bytenr
 187  */
 188 static struct btrfs_block_group_cache *
 189 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 190                               int contains)
 191 {
 192         struct btrfs_block_group_cache *cache, *ret = NULL;
 193         struct rb_node *n;
 194         u64 end, start;
 195
 196         spin_lock(&info->block_group_cache_lock);
 197         n = info->block_group_cache_tree.rb_node;
 198
 199         while (n) {
 200                 cache = rb_entry(n, struct btrfs_block_group_cache,
 201                                  cache_node);
 202                 end = cache->key.objectid + cache->key.offset - 1;
 203                 start = cache->key.objectid;
 204
 205                 if (bytenr < start) {
 206                         if (!contains && (!ret || start < ret->key.objectid))
 207                                 ret = cache;
 208                         n = n->rb_left;
 209                 } else if (bytenr > start) {
 210                         if (contains && bytenr <= end) {
 211                                 ret = cache;
 212                                 break;
 213                         }
 214                         n = n->rb_right;
 215                 } else {
 216                         ret = cache;
 217                         break;
 218                 }
 219         }
 220         if (ret) {
 221                 btrfs_get_block_group(ret);
 222                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 223                         info->first_logical_byte = ret->key.objectid;
 224         }
 225         spin_unlock(&info->block_group_cache_lock);
 226
 227         return ret;
 228 }
 229
 230 static int add_excluded_extent(struct btrfs_root *root,
 231                                u64 start, u64 num_bytes)
 232 {
 233         u64 end = start + num_bytes - 1;
 234         set_extent_bits(&root->fs_info->freed_extents[0],
 235                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 236         set_extent_bits(&root->fs_info->freed_extents[1],
 237                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 238         return 0;
 239 }
 240
 241 static void free_excluded_extents(struct btrfs_root *root,
 242                                   struct btrfs_block_group_cache *cache)
 243 {
 244         u64 start, end;
 245
 246         start = cache->key.objectid;
 247         end = start + cache->key.offset - 1;
 248
 249         clear_extent_bits(&root->fs_info->freed_extents[0],
 250                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 251         clear_extent_bits(&root->fs_info->freed_extents[1],
 252                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 253 }
 254
 255 static int exclude_super_stripes(struct btrfs_root *root,
 256                                  struct btrfs_block_group_cache *cache)
 257 {
 258         u64 bytenr;
 259         u64 *logical;
 260         int stripe_len;
 261         int i, nr, ret;
 262
 263         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 264                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 265                 cache->bytes_super += stripe_len;
 266                 ret = add_excluded_extent(root, cache->key.objectid,
 267                                           stripe_len);
 268                 if (ret)
 269                         return ret;
 270         }
 271
 272         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 273                 bytenr = btrfs_sb_offset(i);
 274                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 275                                        cache->key.objectid, bytenr,
 276                                        0, &logical, &nr, &stripe_len);
 277                 if (ret)
 278                         return ret;
 279
 280                 while (nr--) {
 281                         u64 start, len;
 282
 283                         if (logical[nr] > cache->key.objectid +
 284                             cache->key.offset)
 285                                 continue;
 286
 287                         if (logical[nr] + stripe_len <= cache->key.objectid)
 288                                 continue;
 289
 290                         start = logical[nr];
 291                         if (start < cache->key.objectid) {
 292                                 start = cache->key.objectid;
 293                                 len = (logical[nr] + stripe_len) - start;
 294                         } else {
 295                                 len = min_t(u64, stripe_len,
 296                                             cache->key.objectid +
 297                                             cache->key.offset - start);
 298                         }
 299
 300                         cache->bytes_super += len;
 301                         ret = add_excluded_extent(root, start, len);
 302                         if (ret) {
 303                                 kfree(logical);
 304                                 return ret;
 305                         }
 306                 }
 307
 308                 kfree(logical);
 309         }
 310         return 0;
 311 }
 312
 313 static struct btrfs_caching_control *
 314 get_caching_control(struct btrfs_block_group_cache *cache)
 315 {
 316         struct btrfs_caching_control *ctl;
 317
 318         spin_lock(&cache->lock);
 319         if (!cache->caching_ctl) {
 320                 spin_unlock(&cache->lock);
 321                 return NULL;
 322         }
 323
 324         ctl = cache->caching_ctl;
 325         atomic_inc(&ctl->count);
 326         spin_unlock(&cache->lock);
 327         return ctl;
 328 }
 329
 330 static void put_caching_control(struct btrfs_caching_control *ctl)
 331 {
 332         if (atomic_dec_and_test(&ctl->count))
 333                 kfree(ctl);
 334 }
 335
 336 /*
 337  * this is only called by cache_block_group, since we could have freed extents
 338  * we need to check the pinned_extents for any extents that can't be used yet
 339  * since their free space will be released as soon as the transaction commits.
 340  */
 341 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 342                               struct btrfs_fs_info *info, u64 start, u64 end)
 343 {
 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 noinline void caching_thread(struct btrfs_work *work)
 380 {
 381         struct btrfs_block_group_cache *block_group;
 382         struct btrfs_fs_info *fs_info;
 383         struct btrfs_caching_control *caching_ctl;
 384         struct btrfs_root *extent_root;
 385         struct btrfs_path *path;
 386         struct extent_buffer *leaf;
 387         struct btrfs_key key;
 388         u64 total_found = 0;
 389         u64 last = 0;
 390         u32 nritems;
 391         int ret = -ENOMEM;
 392
 393         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 394         block_group = caching_ctl->block_group;
 395         fs_info = block_group->fs_info;
 396         extent_root = fs_info->extent_root;
 397
 398         path = btrfs_alloc_path();
 399         if (!path)
 400                 goto out;
 401
 402         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 403
 404         /*
 405          * We don't want to deadlock with somebody trying to allocate a new
 406          * extent for the extent root while also trying to search the extent
 407          * root to add free space.  So we skip locking and search the commit
 408          * root, since its read-only
 409          */
 410         path->skip_locking = 1;
 411         path->search_commit_root = 1;
 412         path->reada = 1;
 413
 414         key.objectid = last;
 415         key.offset = 0;
 416         key.type = BTRFS_EXTENT_ITEM_KEY;
 417 again:
 418         mutex_lock(&caching_ctl->mutex);
 419         /* need to make sure the commit_root doesn't disappear */
 420         down_read(&fs_info->commit_root_sem);
 421
 422 next:
 423         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 424         if (ret < 0)
 425                 goto err;
 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                                 caching_ctl->progress = last;
 446                                 btrfs_release_path(path);
 447                                 up_read(&fs_info->commit_root_sem);
 448                                 mutex_unlock(&caching_ctl->mutex);
 449                                 cond_resched();
 450                                 goto again;
 451                         }
 452
 453                         ret = btrfs_next_leaf(extent_root, path);
 454                         if (ret < 0)
 455                                 goto err;
 456                         if (ret)
 457                                 break;
 458                         leaf = path->nodes[0];
 459                         nritems = btrfs_header_nritems(leaf);
 460                         continue;
 461                 }
 462
 463                 if (key.objectid < last) {
 464                         key.objectid = last;
 465                         key.offset = 0;
 466                         key.type = BTRFS_EXTENT_ITEM_KEY;
 467
 468                         caching_ctl->progress = last;
 469                         btrfs_release_path(path);
 470                         goto next;
 471                 }
 472
 473                 if (key.objectid < block_group->key.objectid) {
 474                         path->slots[0]++;
 475                         continue;
 476                 }
 477
 478                 if (key.objectid >= block_group->key.objectid +
 479                     block_group->key.offset)
 480                         break;
 481
 482                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 483                     key.type == BTRFS_METADATA_ITEM_KEY) {
 484                         total_found += add_new_free_space(block_group,
 485                                                           fs_info, last,
 486                                                           key.objectid);
 487                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 488                                 last = key.objectid +
 489                                         fs_info->tree_root->nodesize;
 490                         else
 491                                 last = key.objectid + key.offset;
 492
 493                         if (total_found > (1024 * 1024 * 2)) {
 494                                 total_found = 0;
 495                                 wake_up(&caching_ctl->wait);
 496                         }
 497                 }
 498                 path->slots[0]++;
 499         }
 500         ret = 0;
 501
 502         total_found += add_new_free_space(block_group, fs_info, last,
 503                                           block_group->key.objectid +
 504                                           block_group->key.offset);
 505         caching_ctl->progress = (u64)-1;
 506
 507         spin_lock(&block_group->lock);
 508         block_group->caching_ctl = NULL;
 509         block_group->cached = BTRFS_CACHE_FINISHED;
 510         spin_unlock(&block_group->lock);
 511
 512 err:
 513         btrfs_free_path(path);
 514         up_read(&fs_info->commit_root_sem);
 515
 516         free_excluded_extents(extent_root, block_group);
 517
 518         mutex_unlock(&caching_ctl->mutex);
 519 out:
 520         if (ret) {
 521                 spin_lock(&block_group->lock);
 522                 block_group->caching_ctl = NULL;
 523                 block_group->cached = BTRFS_CACHE_ERROR;
 524                 spin_unlock(&block_group->lock);
 525         }
 526         wake_up(&caching_ctl->wait);
 527
 528         put_caching_control(caching_ctl);
 529         btrfs_put_block_group(block_group);
 530 }
 531
 532 static int cache_block_group(struct btrfs_block_group_cache *cache,
 533                              int load_cache_only)
 534 {
 535         DEFINE_WAIT(wait);
 536         struct btrfs_fs_info *fs_info = cache->fs_info;
 537         struct btrfs_caching_control *caching_ctl;
 538         int ret = 0;
 539
 540         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 541         if (!caching_ctl)
 542                 return -ENOMEM;
 543
 544         INIT_LIST_HEAD(&caching_ctl->list);
 545         mutex_init(&caching_ctl->mutex);
 546         init_waitqueue_head(&caching_ctl->wait);
 547         caching_ctl->block_group = cache;
 548         caching_ctl->progress = cache->key.objectid;
 549         atomic_set(&caching_ctl->count, 1);
 550         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 551                         caching_thread, NULL, NULL);
 552
 553         spin_lock(&cache->lock);
 554         /*
 555          * This should be a rare occasion, but this could happen I think in the
 556          * case where one thread starts to load the space cache info, and then
 557          * some other thread starts a transaction commit which tries to do an
 558          * allocation while the other thread is still loading the space cache
 559          * info.  The previous loop should have kept us from choosing this block
 560          * group, but if we've moved to the state where we will wait on caching
 561          * block groups we need to first check if we're doing a fast load here,
 562          * so we can wait for it to finish, otherwise we could end up allocating
 563          * from a block group who's cache gets evicted for one reason or
 564          * another.
 565          */
 566         while (cache->cached == BTRFS_CACHE_FAST) {
 567                 struct btrfs_caching_control *ctl;
 568
 569                 ctl = cache->caching_ctl;
 570                 atomic_inc(&ctl->count);
 571                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 572                 spin_unlock(&cache->lock);
 573
 574                 schedule();
 575
 576                 finish_wait(&ctl->wait, &wait);
 577                 put_caching_control(ctl);
 578                 spin_lock(&cache->lock);
 579         }
 580
 581         if (cache->cached != BTRFS_CACHE_NO) {
 582                 spin_unlock(&cache->lock);
 583                 kfree(caching_ctl);
 584                 return 0;
 585         }
 586         WARN_ON(cache->caching_ctl);
 587         cache->caching_ctl = caching_ctl;
 588         cache->cached = BTRFS_CACHE_FAST;
 589         spin_unlock(&cache->lock);
 590
 591         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 592                 mutex_lock(&caching_ctl->mutex);
 593                 ret = load_free_space_cache(fs_info, cache);
 594
 595                 spin_lock(&cache->lock);
 596                 if (ret == 1) {
 597                         cache->caching_ctl = NULL;
 598                         cache->cached = BTRFS_CACHE_FINISHED;
 599                         cache->last_byte_to_unpin = (u64)-1;
 600                         caching_ctl->progress = (u64)-1;
 601                 } else {
 602                         if (load_cache_only) {
 603                                 cache->caching_ctl = NULL;
 604                                 cache->cached = BTRFS_CACHE_NO;
 605                         } else {
 606                                 cache->cached = BTRFS_CACHE_STARTED;
 607                                 cache->has_caching_ctl = 1;
 608                         }
 609                 }
 610                 spin_unlock(&cache->lock);
 611                 mutex_unlock(&caching_ctl->mutex);
 612
 613                 wake_up(&caching_ctl->wait);
 614                 if (ret == 1) {
 615                         put_caching_control(caching_ctl);
 616                         free_excluded_extents(fs_info->extent_root, cache);
 617                         return 0;
 618                 }
 619         } else {
 620                 /*
 621                  * We are not going to do the fast caching, set cached to the
 622                  * appropriate value and wakeup any waiters.
 623                  */
 624                 spin_lock(&cache->lock);
 625                 if (load_cache_only) {
 626                         cache->caching_ctl = NULL;
 627                         cache->cached = BTRFS_CACHE_NO;
 628                 } else {
 629                         cache->cached = BTRFS_CACHE_STARTED;
 630                         cache->has_caching_ctl = 1;
 631                 }
 632                 spin_unlock(&cache->lock);
 633                 wake_up(&caching_ctl->wait);
 634         }
 635
 636         if (load_cache_only) {
 637                 put_caching_control(caching_ctl);
 638                 return 0;
 639         }
 640
 641         down_write(&fs_info->commit_root_sem);
 642         atomic_inc(&caching_ctl->count);
 643         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 644         up_write(&fs_info->commit_root_sem);
 645
 646         btrfs_get_block_group(cache);
 647
 648         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 649
 650         return ret;
 651 }
 652
 653 /*
 654  * return the block group that starts at or after bytenr
 655  */
 656 static struct btrfs_block_group_cache *
 657 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 658 {
 659         struct btrfs_block_group_cache *cache;
 660
 661         cache = block_group_cache_tree_search(info, bytenr, 0);
 662
 663         return cache;
 664 }
 665
 666 /*
 667  * return the block group that contains the given bytenr
 668  */
 669 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 670                                                  struct btrfs_fs_info *info,
 671                                                  u64 bytenr)
 672 {
 673         struct btrfs_block_group_cache *cache;
 674
 675         cache = block_group_cache_tree_search(info, bytenr, 1);
 676
 677         return cache;
 678 }
 679
 680 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 681                                                   u64 flags)
 682 {
 683         struct list_head *head = &info->space_info;
 684         struct btrfs_space_info *found;
 685
 686         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 687
 688         rcu_read_lock();
 689         list_for_each_entry_rcu(found, head, list) {
 690                 if (found->flags & flags) {
 691                         rcu_read_unlock();
 692                         return found;
 693                 }
 694         }
 695         rcu_read_unlock();
 696         return NULL;
 697 }
 698
 699 /*
 700  * after adding space to the filesystem, we need to clear the full flags
 701  * on all the space infos.
 702  */
 703 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 704 {
 705         struct list_head *head = &info->space_info;
 706         struct btrfs_space_info *found;
 707
 708         rcu_read_lock();
 709         list_for_each_entry_rcu(found, head, list)
 710                 found->full = 0;
 711         rcu_read_unlock();
 712 }
 713
 714 /* simple helper to search for an existing data extent at a given offset */
 715 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 716 {
 717         int ret;
 718         struct btrfs_key key;
 719         struct btrfs_path *path;
 720
 721         path = btrfs_alloc_path();
 722         if (!path)
 723                 return -ENOMEM;
 724
 725         key.objectid = start;
 726         key.offset = len;
 727         key.type = BTRFS_EXTENT_ITEM_KEY;
 728         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 729                                 0, 0);
 730         btrfs_free_path(path);
 731         return ret;
 732 }
 733
 734 /*
 735  * helper function to lookup reference count and flags of a tree block.
 736  *
 737  * the head node for delayed ref is used to store the sum of all the
 738  * reference count modifications queued up in the rbtree. the head
 739  * node may also store the extent flags to set. This way you can check
 740  * to see what the reference count and extent flags would be if all of
 741  * the delayed refs are not processed.
 742  */
 743 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 744                              struct btrfs_root *root, u64 bytenr,
 745                              u64 offset, int metadata, u64 *refs, u64 *flags)
 746 {
 747         struct btrfs_delayed_ref_head *head;
 748         struct btrfs_delayed_ref_root *delayed_refs;
 749         struct btrfs_path *path;
 750         struct btrfs_extent_item *ei;
 751         struct extent_buffer *leaf;
 752         struct btrfs_key key;
 753         u32 item_size;
 754         u64 num_refs;
 755         u64 extent_flags;
 756         int ret;
 757
 758         /*
 759          * If we don't have skinny metadata, don't bother doing anything
 760          * different
 761          */
 762         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 763                 offset = root->nodesize;
 764                 metadata = 0;
 765         }
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         if (!trans) {
 772                 path->skip_locking = 1;
 773                 path->search_commit_root = 1;
 774         }
 775
 776 search_again:
 777         key.objectid = bytenr;
 778         key.offset = offset;
 779         if (metadata)
 780                 key.type = BTRFS_METADATA_ITEM_KEY;
 781         else
 782                 key.type = BTRFS_EXTENT_ITEM_KEY;
 783
 784         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 785                                 &key, path, 0, 0);
 786         if (ret < 0)
 787                 goto out_free;
 788
 789         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 790                 if (path->slots[0]) {
 791                         path->slots[0]--;
 792                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 793                                               path->slots[0]);
 794                         if (key.objectid == bytenr &&
 795                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 796                             key.offset == root->nodesize)
 797                                 ret = 0;
 798                 }
 799         }
 800
 801         if (ret == 0) {
 802                 leaf = path->nodes[0];
 803                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 804                 if (item_size >= sizeof(*ei)) {
 805                         ei = btrfs_item_ptr(leaf, path->slots[0],
 806                                             struct btrfs_extent_item);
 807                         num_refs = btrfs_extent_refs(leaf, ei);
 808                         extent_flags = btrfs_extent_flags(leaf, ei);
 809                 } else {
 810 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 811                         struct btrfs_extent_item_v0 *ei0;
 812                         BUG_ON(item_size != sizeof(*ei0));
 813                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 814                                              struct btrfs_extent_item_v0);
 815                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 816                         /* FIXME: this isn't correct for data */
 817                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 818 #else
 819                         BUG();
 820 #endif
 821                 }
 822                 BUG_ON(num_refs == 0);
 823         } else {
 824                 num_refs = 0;
 825                 extent_flags = 0;
 826                 ret = 0;
 827         }
 828
 829         if (!trans)
 830                 goto out;
 831
 832         delayed_refs = &trans->transaction->delayed_refs;
 833         spin_lock(&delayed_refs->lock);
 834         head = btrfs_find_delayed_ref_head(trans, bytenr);
 835         if (head) {
 836                 if (!mutex_trylock(&head->mutex)) {
 837                         atomic_inc(&head->node.refs);
 838                         spin_unlock(&delayed_refs->lock);
 839
 840                         btrfs_release_path(path);
 841
 842                         /*
 843                          * Mutex was contended, block until it's released and try
 844                          * again
 845                          */
 846                         mutex_lock(&head->mutex);
 847                         mutex_unlock(&head->mutex);
 848                         btrfs_put_delayed_ref(&head->node);
 849                         goto search_again;
 850                 }
 851                 spin_lock(&head->lock);
 852                 if (head->extent_op && head->extent_op->update_flags)
 853                         extent_flags |= head->extent_op->flags_to_set;
 854                 else
 855                         BUG_ON(num_refs == 0);
 856
 857                 num_refs += head->node.ref_mod;
 858                 spin_unlock(&head->lock);
 859                 mutex_unlock(&head->mutex);
 860         }
 861         spin_unlock(&delayed_refs->lock);
 862 out:
 863         WARN_ON(num_refs == 0);
 864         if (refs)
 865                 *refs = num_refs;
 866         if (flags)
 867                 *flags = extent_flags;
 868 out_free:
 869         btrfs_free_path(path);
 870         return ret;
 871 }
 872
 873 /*
 874  * Back reference rules.  Back refs have three main goals:
 875  *
 876  * 1) differentiate between all holders of references to an extent so that
 877  *    when a reference is dropped we can make sure it was a valid reference
 878  *    before freeing the extent.
 879  *
 880  * 2) Provide enough information to quickly find the holders of an extent
 881  *    if we notice a given block is corrupted or bad.
 882  *
 883  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 884  *    maintenance.  This is actually the same as #2, but with a slightly
 885  *    different use case.
 886  *
 887  * There are two kinds of back refs. The implicit back refs is optimized
 888  * for pointers in non-shared tree blocks. For a given pointer in a block,
 889  * back refs of this kind provide information about the block's owner tree
 890  * and the pointer's key. These information allow us to find the block by
 891  * b-tree searching. The full back refs is for pointers in tree blocks not
 892  * referenced by their owner trees. The location of tree block is recorded
 893  * in the back refs. Actually the full back refs is generic, and can be
 894  * used in all cases the implicit back refs is used. The major shortcoming
 895  * of the full back refs is its overhead. Every time a tree block gets
 896  * COWed, we have to update back refs entry for all pointers in it.
 897  *
 898  * For a newly allocated tree block, we use implicit back refs for
 899  * pointers in it. This means most tree related operations only involve
 900  * implicit back refs. For a tree block created in old transaction, the
 901  * only way to drop a reference to it is COW it. So we can detect the
 902  * event that tree block loses its owner tree's reference and do the
 903  * back refs conversion.
 904  *
 905  * When a tree block is COW'd through a tree, there are four cases:
 906  *
 907  * The reference count of the block is one and the tree is the block's
 908  * owner tree. Nothing to do in this case.
 909  *
 910  * The reference count of the block is one and the tree is not the
 911  * block's owner tree. In this case, full back refs is used for pointers
 912  * in the block. Remove these full back refs, add implicit back refs for
 913  * every pointers in the new block.
 914  *
 915  * The reference count of the block is greater than one and the tree is
 916  * the block's owner tree. In this case, implicit back refs is used for
 917  * pointers in the block. Add full back refs for every pointers in the
 918  * block, increase lower level extents' reference counts. The original
 919  * implicit back refs are entailed to the new block.
 920  *
 921  * The reference count of the block is greater than one and the tree is
 922  * not the block's owner tree. Add implicit back refs for every pointer in
 923  * the new block, increase lower level extents' reference count.
 924  *
 925  * Back Reference Key composing:
 926  *
 927  * The key objectid corresponds to the first byte in the extent,
 928  * The key type is used to differentiate between types of back refs.
 929  * There are different meanings of the key offset for different types
 930  * of back refs.
 931  *
 932  * File extents can be referenced by:
 933  *
 934  * - multiple snapshots, subvolumes, or different generations in one subvol
 935  * - different files inside a single subvolume
 936  * - different offsets inside a file (bookend extents in file.c)
 937  *
 938  * The extent ref structure for the implicit back refs has fields for:
 939  *
 940  * - Objectid of the subvolume root
 941  * - objectid of the file holding the reference
 942  * - original offset in the file
 943  * - how many bookend extents
 944  *
 945  * The key offset for the implicit back refs is hash of the first
 946  * three fields.
 947  *
 948  * The extent ref structure for the full back refs has field for:
 949  *
 950  * - number of pointers in the tree leaf
 951  *
 952  * The key offset for the implicit back refs is the first byte of
 953  * the tree leaf
 954  *
 955  * When a file extent is allocated, The implicit back refs is used.
 956  * the fields are filled in:
 957  *
 958  *     (root_key.objectid, inode objectid, offset in file, 1)
 959  *
 960  * When a file extent is removed file truncation, we find the
 961  * corresponding implicit back refs and check the following fields:
 962  *
 963  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 964  *
 965  * Btree extents can be referenced by:
 966  *
 967  * - Different subvolumes
 968  *
 969  * Both the implicit back refs and the full back refs for tree blocks
 970  * only consist of key. The key offset for the implicit back refs is
 971  * objectid of block's owner tree. The key offset for the full back refs
 972  * is the first byte of parent block.
 973  *
 974  * When implicit back refs is used, information about the lowest key and
 975  * level of the tree block are required. These information are stored in
 976  * tree block info structure.
 977  */
 978
 979 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 980 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 981                                   struct btrfs_root *root,
 982                                   struct btrfs_path *path,
 983                                   u64 owner, u32 extra_size)
 984 {
 985         struct btrfs_extent_item *item;
 986         struct btrfs_extent_item_v0 *ei0;
 987         struct btrfs_extent_ref_v0 *ref0;
 988         struct btrfs_tree_block_info *bi;
 989         struct extent_buffer *leaf;
 990         struct btrfs_key key;
 991         struct btrfs_key found_key;
 992         u32 new_size = sizeof(*item);
 993         u64 refs;
 994         int ret;
 995
 996         leaf = path->nodes[0];
 997         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 998
 999         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1000         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1001                              struct btrfs_extent_item_v0);
1002         refs = btrfs_extent_refs_v0(leaf, ei0);
1003
1004         if (owner == (u64)-1) {
1005                 while (1) {
1006                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1007                                 ret = btrfs_next_leaf(root, path);
1008                                 if (ret < 0)
1009                                         return ret;
1010                                 BUG_ON(ret > 0); /* Corruption */
1011                                 leaf = path->nodes[0];
1012                         }
1013                         btrfs_item_key_to_cpu(leaf, &found_key,
1014                                               path->slots[0]);
1015                         BUG_ON(key.objectid != found_key.objectid);
1016                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1017                                 path->slots[0]++;
1018                                 continue;
1019                         }
1020                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1021                                               struct btrfs_extent_ref_v0);
1022                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1023                         break;
1024                 }
1025         }
1026         btrfs_release_path(path);
1027
1028         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1029                 new_size += sizeof(*bi);
1030
1031         new_size -= sizeof(*ei0);
1032         ret = btrfs_search_slot(trans, root, &key, path,
1033                                 new_size + extra_size, 1);
1034         if (ret < 0)
1035                 return ret;
1036         BUG_ON(ret); /* Corruption */
1037
1038         btrfs_extend_item(root, path, new_size);
1039
1040         leaf = path->nodes[0];
1041         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1042         btrfs_set_extent_refs(leaf, item, refs);
1043         /* FIXME: get real generation */
1044         btrfs_set_extent_generation(leaf, item, 0);
1045         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1046                 btrfs_set_extent_flags(leaf, item,
1047                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1048                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1049                 bi = (struct btrfs_tree_block_info *)(item + 1);
1050                 /* FIXME: get first key of the block */
1051                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1052                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1053         } else {
1054                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1055         }
1056         btrfs_mark_buffer_dirty(leaf);
1057         return 0;
1058 }
1059 #endif
1060
1061 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1062 {
1063         u32 high_crc = ~(u32)0;
1064         u32 low_crc = ~(u32)0;
1065         __le64 lenum;
1066
1067         lenum = cpu_to_le64(root_objectid);
1068         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1069         lenum = cpu_to_le64(owner);
1070         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1071         lenum = cpu_to_le64(offset);
1072         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1073
1074         return ((u64)high_crc << 31) ^ (u64)low_crc;
1075 }
1076
1077 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1078                                      struct btrfs_extent_data_ref *ref)
1079 {
1080         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1081                                     btrfs_extent_data_ref_objectid(leaf, ref),
1082                                     btrfs_extent_data_ref_offset(leaf, ref));
1083 }
1084
1085 static int match_extent_data_ref(struct extent_buffer *leaf,
1086                                  struct btrfs_extent_data_ref *ref,
1087                                  u64 root_objectid, u64 owner, u64 offset)
1088 {
1089         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1090             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1091             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1092                 return 0;
1093         return 1;
1094 }
1095
1096 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1097                                            struct btrfs_root *root,
1098                                            struct btrfs_path *path,
1099                                            u64 bytenr, u64 parent,
1100                                            u64 root_objectid,
1101                                            u64 owner, u64 offset)
1102 {
1103         struct btrfs_key key;
1104         struct btrfs_extent_data_ref *ref;
1105         struct extent_buffer *leaf;
1106         u32 nritems;
1107         int ret;
1108         int recow;
1109         int err = -ENOENT;
1110
1111         key.objectid = bytenr;
1112         if (parent) {
1113                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1114                 key.offset = parent;
1115         } else {
1116                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1117                 key.offset = hash_extent_data_ref(root_objectid,
1118                                                   owner, offset);
1119         }
1120 again:
1121         recow = 0;
1122         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1123         if (ret < 0) {
1124                 err = ret;
1125                 goto fail;
1126         }
1127
1128         if (parent) {
1129                 if (!ret)
1130                         return 0;
1131 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1132                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1133                 btrfs_release_path(path);
1134                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1135                 if (ret < 0) {
1136                         err = ret;
1137                         goto fail;
1138                 }
1139                 if (!ret)
1140                         return 0;
1141 #endif
1142                 goto fail;
1143         }
1144
1145         leaf = path->nodes[0];
1146         nritems = btrfs_header_nritems(leaf);
1147         while (1) {
1148                 if (path->slots[0] >= nritems) {
1149                         ret = btrfs_next_leaf(root, path);
1150                         if (ret < 0)
1151                                 err = ret;
1152                         if (ret)
1153                                 goto fail;
1154
1155                         leaf = path->nodes[0];
1156                         nritems = btrfs_header_nritems(leaf);
1157                         recow = 1;
1158                 }
1159
1160                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1161                 if (key.objectid != bytenr ||
1162                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1163                         goto fail;
1164
1165                 ref = btrfs_item_ptr(leaf, path->slots[0],
1166                                      struct btrfs_extent_data_ref);
1167
1168                 if (match_extent_data_ref(leaf, ref, root_objectid,
1169                                           owner, offset)) {
1170                         if (recow) {
1171                                 btrfs_release_path(path);
1172                                 goto again;
1173                         }
1174                         err = 0;
1175                         break;
1176                 }
1177                 path->slots[0]++;
1178         }
1179 fail:
1180         return err;
1181 }
1182
1183 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1184                                            struct btrfs_root *root,
1185                                            struct btrfs_path *path,
1186                                            u64 bytenr, u64 parent,
1187                                            u64 root_objectid, u64 owner,
1188                                            u64 offset, int refs_to_add)
1189 {
1190         struct btrfs_key key;
1191         struct extent_buffer *leaf;
1192         u32 size;
1193         u32 num_refs;
1194         int ret;
1195
1196         key.objectid = bytenr;
1197         if (parent) {
1198                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1199                 key.offset = parent;
1200                 size = sizeof(struct btrfs_shared_data_ref);
1201         } else {
1202                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1203                 key.offset = hash_extent_data_ref(root_objectid,
1204                                                   owner, offset);
1205                 size = sizeof(struct btrfs_extent_data_ref);
1206         }
1207
1208         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1209         if (ret && ret != -EEXIST)
1210                 goto fail;
1211
1212         leaf = path->nodes[0];
1213         if (parent) {
1214                 struct btrfs_shared_data_ref *ref;
1215                 ref = btrfs_item_ptr(leaf, path->slots[0],
1216                                      struct btrfs_shared_data_ref);
1217                 if (ret == 0) {
1218                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1219                 } else {
1220                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1221                         num_refs += refs_to_add;
1222                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1223                 }
1224         } else {
1225                 struct btrfs_extent_data_ref *ref;
1226                 while (ret == -EEXIST) {
1227                         ref = btrfs_item_ptr(leaf, path->slots[0],
1228                                              struct btrfs_extent_data_ref);
1229                         if (match_extent_data_ref(leaf, ref, root_objectid,
1230                                                   owner, offset))
1231                                 break;
1232                         btrfs_release_path(path);
1233                         key.offset++;
1234                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1235                                                       size);
1236                         if (ret && ret != -EEXIST)
1237                                 goto fail;
1238
1239                         leaf = path->nodes[0];
1240                 }
1241                 ref = btrfs_item_ptr(leaf, path->slots[0],
1242                                      struct btrfs_extent_data_ref);
1243                 if (ret == 0) {
1244                         btrfs_set_extent_data_ref_root(leaf, ref,
1245                                                        root_objectid);
1246                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1247                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1248                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1249                 } else {
1250                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1251                         num_refs += refs_to_add;
1252                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1253                 }
1254         }
1255         btrfs_mark_buffer_dirty(leaf);
1256         ret = 0;
1257 fail:
1258         btrfs_release_path(path);
1259         return ret;
1260 }
1261
1262 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1263                                            struct btrfs_root *root,
1264                                            struct btrfs_path *path,
1265                                            int refs_to_drop, int *last_ref)
1266 {
1267         struct btrfs_key key;
1268         struct btrfs_extent_data_ref *ref1 = NULL;
1269         struct btrfs_shared_data_ref *ref2 = NULL;
1270         struct extent_buffer *leaf;
1271         u32 num_refs = 0;
1272         int ret = 0;
1273
1274         leaf = path->nodes[0];
1275         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1276
1277         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1278                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1279                                       struct btrfs_extent_data_ref);
1280                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1281         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1282                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1283                                       struct btrfs_shared_data_ref);
1284                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1285 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1286         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1287                 struct btrfs_extent_ref_v0 *ref0;
1288                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1289                                       struct btrfs_extent_ref_v0);
1290                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1291 #endif
1292         } else {
1293                 BUG();
1294         }
1295
1296         BUG_ON(num_refs < refs_to_drop);
1297         num_refs -= refs_to_drop;
1298
1299         if (num_refs == 0) {
1300                 ret = btrfs_del_item(trans, root, path);
1301                 *last_ref = 1;
1302         } else {
1303                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1304                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1305                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1306                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1307 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1308                 else {
1309                         struct btrfs_extent_ref_v0 *ref0;
1310                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1311                                         struct btrfs_extent_ref_v0);
1312                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1313                 }
1314 #endif
1315                 btrfs_mark_buffer_dirty(leaf);
1316         }
1317         return ret;
1318 }
1319
1320 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1321                                           struct btrfs_path *path,
1322                                           struct btrfs_extent_inline_ref *iref)
1323 {
1324         struct btrfs_key key;
1325         struct extent_buffer *leaf;
1326         struct btrfs_extent_data_ref *ref1;
1327         struct btrfs_shared_data_ref *ref2;
1328         u32 num_refs = 0;
1329
1330         leaf = path->nodes[0];
1331         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1332         if (iref) {
1333                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1334                     BTRFS_EXTENT_DATA_REF_KEY) {
1335                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1336                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1337                 } else {
1338                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1339                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1340                 }
1341         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1342                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1343                                       struct btrfs_extent_data_ref);
1344                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1345         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1346                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1347                                       struct btrfs_shared_data_ref);
1348                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1349 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1350         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1351                 struct btrfs_extent_ref_v0 *ref0;
1352                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1353                                       struct btrfs_extent_ref_v0);
1354                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1355 #endif
1356         } else {
1357                 WARN_ON(1);
1358         }
1359         return num_refs;
1360 }
1361
1362 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1363                                           struct btrfs_root *root,
1364                                           struct btrfs_path *path,
1365                                           u64 bytenr, u64 parent,
1366                                           u64 root_objectid)
1367 {
1368         struct btrfs_key key;
1369         int ret;
1370
1371         key.objectid = bytenr;
1372         if (parent) {
1373                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1374                 key.offset = parent;
1375         } else {
1376                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1377                 key.offset = root_objectid;
1378         }
1379
1380         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1381         if (ret > 0)
1382                 ret = -ENOENT;
1383 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1384         if (ret == -ENOENT && parent) {
1385                 btrfs_release_path(path);
1386                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1387                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1388                 if (ret > 0)
1389                         ret = -ENOENT;
1390         }
1391 #endif
1392         return ret;
1393 }
1394
1395 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1396                                           struct btrfs_root *root,
1397                                           struct btrfs_path *path,
1398                                           u64 bytenr, u64 parent,
1399                                           u64 root_objectid)
1400 {
1401         struct btrfs_key key;
1402         int ret;
1403
1404         key.objectid = bytenr;
1405         if (parent) {
1406                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1407                 key.offset = parent;
1408         } else {
1409                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1410                 key.offset = root_objectid;
1411         }
1412
1413         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1414         btrfs_release_path(path);
1415         return ret;
1416 }
1417
1418 static inline int extent_ref_type(u64 parent, u64 owner)
1419 {
1420         int type;
1421         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1422                 if (parent > 0)
1423                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1424                 else
1425                         type = BTRFS_TREE_BLOCK_REF_KEY;
1426         } else {
1427                 if (parent > 0)
1428                         type = BTRFS_SHARED_DATA_REF_KEY;
1429                 else
1430                         type = BTRFS_EXTENT_DATA_REF_KEY;
1431         }
1432         return type;
1433 }
1434
1435 static int find_next_key(struct btrfs_path *path, int level,
1436                          struct btrfs_key *key)
1437
1438 {
1439         for (; level < BTRFS_MAX_LEVEL; level++) {
1440                 if (!path->nodes[level])
1441                         break;
1442                 if (path->slots[level] + 1 >=
1443                     btrfs_header_nritems(path->nodes[level]))
1444                         continue;
1445                 if (level == 0)
1446                         btrfs_item_key_to_cpu(path->nodes[level], key,
1447                                               path->slots[level] + 1);
1448                 else
1449                         btrfs_node_key_to_cpu(path->nodes[level], key,
1450                                               path->slots[level] + 1);
1451                 return 0;
1452         }
1453         return 1;
1454 }
1455
1456 /*
1457  * look for inline back ref. if back ref is found, *ref_ret is set
1458  * to the address of inline back ref, and 0 is returned.
1459  *
1460  * if back ref isn't found, *ref_ret is set to the address where it
1461  * should be inserted, and -ENOENT is returned.
1462  *
1463  * if insert is true and there are too many inline back refs, the path
1464  * points to the extent item, and -EAGAIN is returned.
1465  *
1466  * NOTE: inline back refs are ordered in the same way that back ref
1467  *       items in the tree are ordered.
1468  */
1469 static noinline_for_stack
1470 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1471                                  struct btrfs_root *root,
1472                                  struct btrfs_path *path,
1473                                  struct btrfs_extent_inline_ref **ref_ret,
1474                                  u64 bytenr, u64 num_bytes,
1475                                  u64 parent, u64 root_objectid,
1476                                  u64 owner, u64 offset, int insert)
1477 {
1478         struct btrfs_key key;
1479         struct extent_buffer *leaf;
1480         struct btrfs_extent_item *ei;
1481         struct btrfs_extent_inline_ref *iref;
1482         u64 flags;
1483         u64 item_size;
1484         unsigned long ptr;
1485         unsigned long end;
1486         int extra_size;
1487         int type;
1488         int want;
1489         int ret;
1490         int err = 0;
1491         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1492                                                  SKINNY_METADATA);
1493
1494         key.objectid = bytenr;
1495         key.type = BTRFS_EXTENT_ITEM_KEY;
1496         key.offset = num_bytes;
1497
1498         want = extent_ref_type(parent, owner);
1499         if (insert) {
1500                 extra_size = btrfs_extent_inline_ref_size(want);
1501                 path->keep_locks = 1;
1502         } else
1503                 extra_size = -1;
1504
1505         /*
1506          * Owner is our parent level, so we can just add one to get the level
1507          * for the block we are interested in.
1508          */
1509         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1510                 key.type = BTRFS_METADATA_ITEM_KEY;
1511                 key.offset = owner;
1512         }
1513
1514 again:
1515         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1516         if (ret < 0) {
1517                 err = ret;
1518                 goto out;
1519         }
1520
1521         /*
1522          * We may be a newly converted file system which still has the old fat
1523          * extent entries for metadata, so try and see if we have one of those.
1524          */
1525         if (ret > 0 && skinny_metadata) {
1526                 skinny_metadata = false;
1527                 if (path->slots[0]) {
1528                         path->slots[0]--;
1529                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1530                                               path->slots[0]);
1531                         if (key.objectid == bytenr &&
1532                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1533                             key.offset == num_bytes)
1534                                 ret = 0;
1535                 }
1536                 if (ret) {
1537                         key.objectid = bytenr;
1538                         key.type = BTRFS_EXTENT_ITEM_KEY;
1539                         key.offset = num_bytes;
1540                         btrfs_release_path(path);
1541                         goto again;
1542                 }
1543         }
1544
1545         if (ret && !insert) {
1546                 err = -ENOENT;
1547                 goto out;
1548         } else if (WARN_ON(ret)) {
1549                 err = -EIO;
1550                 goto out;
1551         }
1552
1553         leaf = path->nodes[0];
1554         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1555 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1556         if (item_size < sizeof(*ei)) {
1557                 if (!insert) {
1558                         err = -ENOENT;
1559                         goto out;
1560                 }
1561                 ret = convert_extent_item_v0(trans, root, path, owner,
1562                                              extra_size);
1563                 if (ret < 0) {
1564                         err = ret;
1565                         goto out;
1566                 }
1567                 leaf = path->nodes[0];
1568                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1569         }
1570 #endif
1571         BUG_ON(item_size < sizeof(*ei));
1572
1573         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1574         flags = btrfs_extent_flags(leaf, ei);
1575
1576         ptr = (unsigned long)(ei + 1);
1577         end = (unsigned long)ei + item_size;
1578
1579         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1580                 ptr += sizeof(struct btrfs_tree_block_info);
1581                 BUG_ON(ptr > end);
1582         }
1583
1584         err = -ENOENT;
1585         while (1) {
1586                 if (ptr >= end) {
1587                         WARN_ON(ptr > end);
1588                         break;
1589                 }
1590                 iref = (struct btrfs_extent_inline_ref *)ptr;
1591                 type = btrfs_extent_inline_ref_type(leaf, iref);
1592                 if (want < type)
1593                         break;
1594                 if (want > type) {
1595                         ptr += btrfs_extent_inline_ref_size(type);
1596                         continue;
1597                 }
1598
1599                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1600                         struct btrfs_extent_data_ref *dref;
1601                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1602                         if (match_extent_data_ref(leaf, dref, root_objectid,
1603                                                   owner, offset)) {
1604                                 err = 0;
1605                                 break;
1606                         }
1607                         if (hash_extent_data_ref_item(leaf, dref) <
1608                             hash_extent_data_ref(root_objectid, owner, offset))
1609                                 break;
1610                 } else {
1611                         u64 ref_offset;
1612                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1613                         if (parent > 0) {
1614                                 if (parent == ref_offset) {
1615                                         err = 0;
1616                                         break;
1617                                 }
1618                                 if (ref_offset < parent)
1619                                         break;
1620                         } else {
1621                                 if (root_objectid == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < root_objectid)
1626                                         break;
1627                         }
1628                 }
1629                 ptr += btrfs_extent_inline_ref_size(type);
1630         }
1631         if (err == -ENOENT && insert) {
1632                 if (item_size + extra_size >=
1633                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1634                         err = -EAGAIN;
1635                         goto out;
1636                 }
1637                 /*
1638                  * To add new inline back ref, we have to make sure
1639                  * there is no corresponding back ref item.
1640                  * For simplicity, we just do not add new inline back
1641                  * ref if there is any kind of item for this block
1642                  */
1643                 if (find_next_key(path, 0, &key) == 0 &&
1644                     key.objectid == bytenr &&
1645                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1646                         err = -EAGAIN;
1647                         goto out;
1648                 }
1649         }
1650         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1651 out:
1652         if (insert) {
1653                 path->keep_locks = 0;
1654                 btrfs_unlock_up_safe(path, 1);
1655         }
1656         return err;
1657 }
1658
1659 /*
1660  * helper to add new inline back ref
1661  */
1662 static noinline_for_stack
1663 void setup_inline_extent_backref(struct btrfs_root *root,
1664                                  struct btrfs_path *path,
1665                                  struct btrfs_extent_inline_ref *iref,
1666                                  u64 parent, u64 root_objectid,
1667                                  u64 owner, u64 offset, int refs_to_add,
1668                                  struct btrfs_delayed_extent_op *extent_op)
1669 {
1670         struct extent_buffer *leaf;
1671         struct btrfs_extent_item *ei;
1672         unsigned long ptr;
1673         unsigned long end;
1674         unsigned long item_offset;
1675         u64 refs;
1676         int size;
1677         int type;
1678
1679         leaf = path->nodes[0];
1680         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1681         item_offset = (unsigned long)iref - (unsigned long)ei;
1682
1683         type = extent_ref_type(parent, owner);
1684         size = btrfs_extent_inline_ref_size(type);
1685
1686         btrfs_extend_item(root, path, size);
1687
1688         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1689         refs = btrfs_extent_refs(leaf, ei);
1690         refs += refs_to_add;
1691         btrfs_set_extent_refs(leaf, ei, refs);
1692         if (extent_op)
1693                 __run_delayed_extent_op(extent_op, leaf, ei);
1694
1695         ptr = (unsigned long)ei + item_offset;
1696         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1697         if (ptr < end - size)
1698                 memmove_extent_buffer(leaf, ptr + size, ptr,
1699                                       end - size - ptr);
1700
1701         iref = (struct btrfs_extent_inline_ref *)ptr;
1702         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1703         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1704                 struct btrfs_extent_data_ref *dref;
1705                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1706                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1707                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1708                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1709                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1710         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1711                 struct btrfs_shared_data_ref *sref;
1712                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1713                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1714                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1715         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1716                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1717         } else {
1718                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1719         }
1720         btrfs_mark_buffer_dirty(leaf);
1721 }
1722
1723 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1724                                  struct btrfs_root *root,
1725                                  struct btrfs_path *path,
1726                                  struct btrfs_extent_inline_ref **ref_ret,
1727                                  u64 bytenr, u64 num_bytes, u64 parent,
1728                                  u64 root_objectid, u64 owner, u64 offset)
1729 {
1730         int ret;
1731
1732         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1733                                            bytenr, num_bytes, parent,
1734                                            root_objectid, owner, offset, 0);
1735         if (ret != -ENOENT)
1736                 return ret;
1737
1738         btrfs_release_path(path);
1739         *ref_ret = NULL;
1740
1741         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1742                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1743                                             root_objectid);
1744         } else {
1745                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1746                                              root_objectid, owner, offset);
1747         }
1748         return ret;
1749 }
1750
1751 /*
1752  * helper to update/remove inline back ref
1753  */
1754 static noinline_for_stack
1755 void update_inline_extent_backref(struct btrfs_root *root,
1756                                   struct btrfs_path *path,
1757                                   struct btrfs_extent_inline_ref *iref,
1758                                   int refs_to_mod,
1759                                   struct btrfs_delayed_extent_op *extent_op,
1760                                   int *last_ref)
1761 {
1762         struct extent_buffer *leaf;
1763         struct btrfs_extent_item *ei;
1764         struct btrfs_extent_data_ref *dref = NULL;
1765         struct btrfs_shared_data_ref *sref = NULL;
1766         unsigned long ptr;
1767         unsigned long end;
1768         u32 item_size;
1769         int size;
1770         int type;
1771         u64 refs;
1772
1773         leaf = path->nodes[0];
1774         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1775         refs = btrfs_extent_refs(leaf, ei);
1776         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1777         refs += refs_to_mod;
1778         btrfs_set_extent_refs(leaf, ei, refs);
1779         if (extent_op)
1780                 __run_delayed_extent_op(extent_op, leaf, ei);
1781
1782         type = btrfs_extent_inline_ref_type(leaf, iref);
1783
1784         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1785                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1786                 refs = btrfs_extent_data_ref_count(leaf, dref);
1787         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1788                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1789                 refs = btrfs_shared_data_ref_count(leaf, sref);
1790         } else {
1791                 refs = 1;
1792                 BUG_ON(refs_to_mod != -1);
1793         }
1794
1795         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1796         refs += refs_to_mod;
1797
1798         if (refs > 0) {
1799                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1800                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1801                 else
1802                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1803         } else {
1804                 *last_ref = 1;
1805                 size =  btrfs_extent_inline_ref_size(type);
1806                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1807                 ptr = (unsigned long)iref;
1808                 end = (unsigned long)ei + item_size;
1809                 if (ptr + size < end)
1810                         memmove_extent_buffer(leaf, ptr, ptr + size,
1811                                               end - ptr - size);
1812                 item_size -= size;
1813                 btrfs_truncate_item(root, path, item_size, 1);
1814         }
1815         btrfs_mark_buffer_dirty(leaf);
1816 }
1817
1818 static noinline_for_stack
1819 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1820                                  struct btrfs_root *root,
1821                                  struct btrfs_path *path,
1822                                  u64 bytenr, u64 num_bytes, u64 parent,
1823                                  u64 root_objectid, u64 owner,
1824                                  u64 offset, int refs_to_add,
1825                                  struct btrfs_delayed_extent_op *extent_op)
1826 {
1827         struct btrfs_extent_inline_ref *iref;
1828         int ret;
1829
1830         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1831                                            bytenr, num_bytes, parent,
1832                                            root_objectid, owner, offset, 1);
1833         if (ret == 0) {
1834                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1835                 update_inline_extent_backref(root, path, iref,
1836                                              refs_to_add, extent_op, NULL);
1837         } else if (ret == -ENOENT) {
1838                 setup_inline_extent_backref(root, path, iref, parent,
1839                                             root_objectid, owner, offset,
1840                                             refs_to_add, extent_op);
1841                 ret = 0;
1842         }
1843         return ret;
1844 }
1845
1846 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1847                                  struct btrfs_root *root,
1848                                  struct btrfs_path *path,
1849                                  u64 bytenr, u64 parent, u64 root_objectid,
1850                                  u64 owner, u64 offset, int refs_to_add)
1851 {
1852         int ret;
1853         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1854                 BUG_ON(refs_to_add != 1);
1855                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1856                                             parent, root_objectid);
1857         } else {
1858                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1859                                              parent, root_objectid,
1860                                              owner, offset, refs_to_add);
1861         }
1862         return ret;
1863 }
1864
1865 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1866                                  struct btrfs_root *root,
1867                                  struct btrfs_path *path,
1868                                  struct btrfs_extent_inline_ref *iref,
1869                                  int refs_to_drop, int is_data, int *last_ref)
1870 {
1871         int ret = 0;
1872
1873         BUG_ON(!is_data && refs_to_drop != 1);
1874         if (iref) {
1875                 update_inline_extent_backref(root, path, iref,
1876                                              -refs_to_drop, NULL, last_ref);
1877         } else if (is_data) {
1878                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1879                                              last_ref);
1880         } else {
1881                 *last_ref = 1;
1882                 ret = btrfs_del_item(trans, root, path);
1883         }
1884         return ret;
1885 }
1886
1887 static int btrfs_issue_discard(struct block_device *bdev,
1888                                 u64 start, u64 len)
1889 {
1890         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1891 }
1892
1893 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1894                          u64 num_bytes, u64 *actual_bytes)
1895 {
1896         int ret;
1897         u64 discarded_bytes = 0;
1898         struct btrfs_bio *bbio = NULL;
1899
1900
1901         /* Tell the block device(s) that the sectors can be discarded */
1902         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1903                               bytenr, &num_bytes, &bbio, 0);
1904         /* Error condition is -ENOMEM */
1905         if (!ret) {
1906                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1907                 int i;
1908
1909
1910                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1911                         if (!stripe->dev->can_discard)
1912                                 continue;
1913
1914                         ret = btrfs_issue_discard(stripe->dev->bdev,
1915                                                   stripe->physical,
1916                                                   stripe->length);
1917                         if (!ret)
1918                                 discarded_bytes += stripe->length;
1919                         else if (ret != -EOPNOTSUPP)
1920                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1921
1922                         /*
1923                          * Just in case we get back EOPNOTSUPP for some reason,
1924                          * just ignore the return value so we don't screw up
1925                          * people calling discard_extent.
1926                          */
1927                         ret = 0;
1928                 }
1929                 btrfs_put_bbio(bbio);
1930         }
1931
1932         if (actual_bytes)
1933                 *actual_bytes = discarded_bytes;
1934
1935
1936         if (ret == -EOPNOTSUPP)
1937                 ret = 0;
1938         return ret;
1939 }
1940
1941 /* Can return -ENOMEM */
1942 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1943                          struct btrfs_root *root,
1944                          u64 bytenr, u64 num_bytes, u64 parent,
1945                          u64 root_objectid, u64 owner, u64 offset,
1946                          int no_quota)
1947 {
1948         int ret;
1949         struct btrfs_fs_info *fs_info = root->fs_info;
1950
1951         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1952                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1953
1954         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1955                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1956                                         num_bytes,
1957                                         parent, root_objectid, (int)owner,
1958                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1959         } else {
1960                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1961                                         num_bytes,
1962                                         parent, root_objectid, owner, offset,
1963                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1964         }
1965         return ret;
1966 }
1967
1968 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1969                                   struct btrfs_root *root,
1970                                   u64 bytenr, u64 num_bytes,
1971                                   u64 parent, u64 root_objectid,
1972                                   u64 owner, u64 offset, int refs_to_add,
1973                                   int no_quota,
1974                                   struct btrfs_delayed_extent_op *extent_op)
1975 {
1976         struct btrfs_fs_info *fs_info = root->fs_info;
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         struct btrfs_key key;
1981         u64 refs;
1982         int ret;
1983         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_ADD_EXCL;
1984
1985         path = btrfs_alloc_path();
1986         if (!path)
1987                 return -ENOMEM;
1988
1989         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
1990                 no_quota = 1;
1991
1992         path->reada = 1;
1993         path->leave_spinning = 1;
1994         /* this will setup the path even if it fails to insert the back ref */
1995         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
1996                                            bytenr, num_bytes, parent,
1997                                            root_objectid, owner, offset,
1998                                            refs_to_add, extent_op);
1999         if ((ret < 0 && ret != -EAGAIN) || (!ret && no_quota))
2000                 goto out;
2001         /*
2002          * Ok we were able to insert an inline extent and it appears to be a new
2003          * reference, deal with the qgroup accounting.
2004          */
2005         if (!ret && !no_quota) {
2006                 ASSERT(root->fs_info->quota_enabled);
2007                 leaf = path->nodes[0];
2008                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2009                 item = btrfs_item_ptr(leaf, path->slots[0],
2010                                       struct btrfs_extent_item);
2011                 if (btrfs_extent_refs(leaf, item) > (u64)refs_to_add)
2012                         type = BTRFS_QGROUP_OPER_ADD_SHARED;
2013                 btrfs_release_path(path);
2014
2015                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2016                                               bytenr, num_bytes, type, 0);
2017                 goto out;
2018         }
2019
2020         /*
2021          * Ok we had -EAGAIN which means we didn't have space to insert and
2022          * inline extent ref, so just update the reference count and add a
2023          * normal backref.
2024          */
2025         leaf = path->nodes[0];
2026         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2027         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2028         refs = btrfs_extent_refs(leaf, item);
2029         if (refs)
2030                 type = BTRFS_QGROUP_OPER_ADD_SHARED;
2031         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2032         if (extent_op)
2033                 __run_delayed_extent_op(extent_op, leaf, item);
2034
2035         btrfs_mark_buffer_dirty(leaf);
2036         btrfs_release_path(path);
2037
2038         if (!no_quota) {
2039                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2040                                               bytenr, num_bytes, type, 0);
2041                 if (ret)
2042                         goto out;
2043         }
2044
2045         path->reada = 1;
2046         path->leave_spinning = 1;
2047         /* now insert the actual backref */
2048         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2049                                     path, bytenr, parent, root_objectid,
2050                                     owner, offset, refs_to_add);
2051         if (ret)
2052                 btrfs_abort_transaction(trans, root, ret);
2053 out:
2054         btrfs_free_path(path);
2055         return ret;
2056 }
2057
2058 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2059                                 struct btrfs_root *root,
2060                                 struct btrfs_delayed_ref_node *node,
2061                                 struct btrfs_delayed_extent_op *extent_op,
2062                                 int insert_reserved)
2063 {
2064         int ret = 0;
2065         struct btrfs_delayed_data_ref *ref;
2066         struct btrfs_key ins;
2067         u64 parent = 0;
2068         u64 ref_root = 0;
2069         u64 flags = 0;
2070
2071         ins.objectid = node->bytenr;
2072         ins.offset = node->num_bytes;
2073         ins.type = BTRFS_EXTENT_ITEM_KEY;
2074
2075         ref = btrfs_delayed_node_to_data_ref(node);
2076         trace_run_delayed_data_ref(node, ref, node->action);
2077
2078         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2079                 parent = ref->parent;
2080         ref_root = ref->root;
2081
2082         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2083                 if (extent_op)
2084                         flags |= extent_op->flags_to_set;
2085                 ret = alloc_reserved_file_extent(trans, root,
2086                                                  parent, ref_root, flags,
2087                                                  ref->objectid, ref->offset,
2088                                                  &ins, node->ref_mod);
2089         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2090                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2091                                              node->num_bytes, parent,
2092                                              ref_root, ref->objectid,
2093                                              ref->offset, node->ref_mod,
2094                                              node->no_quota, extent_op);
2095         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2096                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2097                                           node->num_bytes, parent,
2098                                           ref_root, ref->objectid,
2099                                           ref->offset, node->ref_mod,
2100                                           extent_op, node->no_quota);
2101         } else {
2102                 BUG();
2103         }
2104         return ret;
2105 }
2106
2107 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2108                                     struct extent_buffer *leaf,
2109                                     struct btrfs_extent_item *ei)
2110 {
2111         u64 flags = btrfs_extent_flags(leaf, ei);
2112         if (extent_op->update_flags) {
2113                 flags |= extent_op->flags_to_set;
2114                 btrfs_set_extent_flags(leaf, ei, flags);
2115         }
2116
2117         if (extent_op->update_key) {
2118                 struct btrfs_tree_block_info *bi;
2119                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2120                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2121                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2122         }
2123 }
2124
2125 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2126                                  struct btrfs_root *root,
2127                                  struct btrfs_delayed_ref_node *node,
2128                                  struct btrfs_delayed_extent_op *extent_op)
2129 {
2130         struct btrfs_key key;
2131         struct btrfs_path *path;
2132         struct btrfs_extent_item *ei;
2133         struct extent_buffer *leaf;
2134         u32 item_size;
2135         int ret;
2136         int err = 0;
2137         int metadata = !extent_op->is_data;
2138
2139         if (trans->aborted)
2140                 return 0;
2141
2142         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2143                 metadata = 0;
2144
2145         path = btrfs_alloc_path();
2146         if (!path)
2147                 return -ENOMEM;
2148
2149         key.objectid = node->bytenr;
2150
2151         if (metadata) {
2152                 key.type = BTRFS_METADATA_ITEM_KEY;
2153                 key.offset = extent_op->level;
2154         } else {
2155                 key.type = BTRFS_EXTENT_ITEM_KEY;
2156                 key.offset = node->num_bytes;
2157         }
2158
2159 again:
2160         path->reada = 1;
2161         path->leave_spinning = 1;
2162         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2163                                 path, 0, 1);
2164         if (ret < 0) {
2165                 err = ret;
2166                 goto out;
2167         }
2168         if (ret > 0) {
2169                 if (metadata) {
2170                         if (path->slots[0] > 0) {
2171                                 path->slots[0]--;
2172                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2173                                                       path->slots[0]);
2174                                 if (key.objectid == node->bytenr &&
2175                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2176                                     key.offset == node->num_bytes)
2177                                         ret = 0;
2178                         }
2179                         if (ret > 0) {
2180                                 btrfs_release_path(path);
2181                                 metadata = 0;
2182
2183                                 key.objectid = node->bytenr;
2184                                 key.offset = node->num_bytes;
2185                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2186                                 goto again;
2187                         }
2188                 } else {
2189                         err = -EIO;
2190                         goto out;
2191                 }
2192         }
2193
2194         leaf = path->nodes[0];
2195         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2196 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2197         if (item_size < sizeof(*ei)) {
2198                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2199                                              path, (u64)-1, 0);
2200                 if (ret < 0) {
2201                         err = ret;
2202                         goto out;
2203                 }
2204                 leaf = path->nodes[0];
2205                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2206         }
2207 #endif
2208         BUG_ON(item_size < sizeof(*ei));
2209         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2210         __run_delayed_extent_op(extent_op, leaf, ei);
2211
2212         btrfs_mark_buffer_dirty(leaf);
2213 out:
2214         btrfs_free_path(path);
2215         return err;
2216 }
2217
2218 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2219                                 struct btrfs_root *root,
2220                                 struct btrfs_delayed_ref_node *node,
2221                                 struct btrfs_delayed_extent_op *extent_op,
2222                                 int insert_reserved)
2223 {
2224         int ret = 0;
2225         struct btrfs_delayed_tree_ref *ref;
2226         struct btrfs_key ins;
2227         u64 parent = 0;
2228         u64 ref_root = 0;
2229         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2230                                                  SKINNY_METADATA);
2231
2232         ref = btrfs_delayed_node_to_tree_ref(node);
2233         trace_run_delayed_tree_ref(node, ref, node->action);
2234
2235         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2236                 parent = ref->parent;
2237         ref_root = ref->root;
2238
2239         ins.objectid = node->bytenr;
2240         if (skinny_metadata) {
2241                 ins.offset = ref->level;
2242                 ins.type = BTRFS_METADATA_ITEM_KEY;
2243         } else {
2244                 ins.offset = node->num_bytes;
2245                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2246         }
2247
2248         BUG_ON(node->ref_mod != 1);
2249         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2250                 BUG_ON(!extent_op || !extent_op->update_flags);
2251                 ret = alloc_reserved_tree_block(trans, root,
2252                                                 parent, ref_root,
2253                                                 extent_op->flags_to_set,
2254                                                 &extent_op->key,
2255                                                 ref->level, &ins,
2256                                                 node->no_quota);
2257         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2258                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2259                                              node->num_bytes, parent, ref_root,
2260                                              ref->level, 0, 1, node->no_quota,
2261                                              extent_op);
2262         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2263                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2264                                           node->num_bytes, parent, ref_root,
2265                                           ref->level, 0, 1, extent_op,
2266                                           node->no_quota);
2267         } else {
2268                 BUG();
2269         }
2270         return ret;
2271 }
2272
2273 /* helper function to actually process a single delayed ref entry */
2274 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2275                                struct btrfs_root *root,
2276                                struct btrfs_delayed_ref_node *node,
2277                                struct btrfs_delayed_extent_op *extent_op,
2278                                int insert_reserved)
2279 {
2280         int ret = 0;
2281
2282         if (trans->aborted) {
2283                 if (insert_reserved)
2284                         btrfs_pin_extent(root, node->bytenr,
2285                                          node->num_bytes, 1);
2286                 return 0;
2287         }
2288
2289         if (btrfs_delayed_ref_is_head(node)) {
2290                 struct btrfs_delayed_ref_head *head;
2291                 /*
2292                  * we've hit the end of the chain and we were supposed
2293                  * to insert this extent into the tree.  But, it got
2294                  * deleted before we ever needed to insert it, so all
2295                  * we have to do is clean up the accounting
2296                  */
2297                 BUG_ON(extent_op);
2298                 head = btrfs_delayed_node_to_head(node);
2299                 trace_run_delayed_ref_head(node, head, node->action);
2300
2301                 if (insert_reserved) {
2302                         btrfs_pin_extent(root, node->bytenr,
2303                                          node->num_bytes, 1);
2304                         if (head->is_data) {
2305                                 ret = btrfs_del_csums(trans, root,
2306                                                       node->bytenr,
2307                                                       node->num_bytes);
2308                         }
2309                 }
2310                 return ret;
2311         }
2312
2313         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2314             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2315                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2316                                            insert_reserved);
2317         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2318                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2319                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2320                                            insert_reserved);
2321         else
2322                 BUG();
2323         return ret;
2324 }
2325
2326 static noinline struct btrfs_delayed_ref_node *
2327 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2328 {
2329         struct rb_node *node;
2330         struct btrfs_delayed_ref_node *ref, *last = NULL;;
2331
2332         /*
2333          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2334          * this prevents ref count from going down to zero when
2335          * there still are pending delayed ref.
2336          */
2337         node = rb_first(&head->ref_root);
2338         while (node) {
2339                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2340                                 rb_node);
2341                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2342                         return ref;
2343                 else if (last == NULL)
2344                         last = ref;
2345                 node = rb_next(node);
2346         }
2347         return last;
2348 }
2349
2350 /*
2351  * Returns 0 on success or if called with an already aborted transaction.
2352  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2353  */
2354 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2355                                              struct btrfs_root *root,
2356                                              unsigned long nr)
2357 {
2358         struct btrfs_delayed_ref_root *delayed_refs;
2359         struct btrfs_delayed_ref_node *ref;
2360         struct btrfs_delayed_ref_head *locked_ref = NULL;
2361         struct btrfs_delayed_extent_op *extent_op;
2362         struct btrfs_fs_info *fs_info = root->fs_info;
2363         ktime_t start = ktime_get();
2364         int ret;
2365         unsigned long count = 0;
2366         unsigned long actual_count = 0;
2367         int must_insert_reserved = 0;
2368
2369         delayed_refs = &trans->transaction->delayed_refs;
2370         while (1) {
2371                 if (!locked_ref) {
2372                         if (count >= nr)
2373                                 break;
2374
2375                         spin_lock(&delayed_refs->lock);
2376                         locked_ref = btrfs_select_ref_head(trans);
2377                         if (!locked_ref) {
2378                                 spin_unlock(&delayed_refs->lock);
2379                                 break;
2380                         }
2381
2382                         /* grab the lock that says we are going to process
2383                          * all the refs for this head */
2384                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2385                         spin_unlock(&delayed_refs->lock);
2386                         /*
2387                          * we may have dropped the spin lock to get the head
2388                          * mutex lock, and that might have given someone else
2389                          * time to free the head.  If that's true, it has been
2390                          * removed from our list and we can move on.
2391                          */
2392                         if (ret == -EAGAIN) {
2393                                 locked_ref = NULL;
2394                                 count++;
2395                                 continue;
2396                         }
2397                 }
2398
2399                 /*
2400                  * We need to try and merge add/drops of the same ref since we
2401                  * can run into issues with relocate dropping the implicit ref
2402                  * and then it being added back again before the drop can
2403                  * finish.  If we merged anything we need to re-loop so we can
2404                  * get a good ref.
2405                  */
2406                 spin_lock(&locked_ref->lock);
2407                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2408                                          locked_ref);
2409
2410                 /*
2411                  * locked_ref is the head node, so we have to go one
2412                  * node back for any delayed ref updates
2413                  */
2414                 ref = select_delayed_ref(locked_ref);
2415
2416                 if (ref && ref->seq &&
2417                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2418                         spin_unlock(&locked_ref->lock);
2419                         btrfs_delayed_ref_unlock(locked_ref);
2420                         spin_lock(&delayed_refs->lock);
2421                         locked_ref->processing = 0;
2422                         delayed_refs->num_heads_ready++;
2423                         spin_unlock(&delayed_refs->lock);
2424                         locked_ref = NULL;
2425                         cond_resched();
2426                         count++;
2427                         continue;
2428                 }
2429
2430                 /*
2431                  * record the must insert reserved flag before we
2432                  * drop the spin lock.
2433                  */
2434                 must_insert_reserved = locked_ref->must_insert_reserved;
2435                 locked_ref->must_insert_reserved = 0;
2436
2437                 extent_op = locked_ref->extent_op;
2438                 locked_ref->extent_op = NULL;
2439
2440                 if (!ref) {
2441
2442
2443                         /* All delayed refs have been processed, Go ahead
2444                          * and send the head node to run_one_delayed_ref,
2445                          * so that any accounting fixes can happen
2446                          */
2447                         ref = &locked_ref->node;
2448
2449                         if (extent_op && must_insert_reserved) {
2450                                 btrfs_free_delayed_extent_op(extent_op);
2451                                 extent_op = NULL;
2452                         }
2453
2454                         if (extent_op) {
2455                                 spin_unlock(&locked_ref->lock);
2456                                 ret = run_delayed_extent_op(trans, root,
2457                                                             ref, extent_op);
2458                                 btrfs_free_delayed_extent_op(extent_op);
2459
2460                                 if (ret) {
2461                                         /*
2462                                          * Need to reset must_insert_reserved if
2463                                          * there was an error so the abort stuff
2464                                          * can cleanup the reserved space
2465                                          * properly.
2466                                          */
2467                                         if (must_insert_reserved)
2468                                                 locked_ref->must_insert_reserved = 1;
2469                                         locked_ref->processing = 0;
2470                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2471                                         btrfs_delayed_ref_unlock(locked_ref);
2472                                         return ret;
2473                                 }
2474                                 continue;
2475                         }
2476
2477                         /*
2478                          * Need to drop our head ref lock and re-aqcuire the
2479                          * delayed ref lock and then re-check to make sure
2480                          * nobody got added.
2481                          */
2482                         spin_unlock(&locked_ref->lock);
2483                         spin_lock(&delayed_refs->lock);
2484                         spin_lock(&locked_ref->lock);
2485                         if (rb_first(&locked_ref->ref_root) ||
2486                             locked_ref->extent_op) {
2487                                 spin_unlock(&locked_ref->lock);
2488                                 spin_unlock(&delayed_refs->lock);
2489                                 continue;
2490                         }
2491                         ref->in_tree = 0;
2492                         delayed_refs->num_heads--;
2493                         rb_erase(&locked_ref->href_node,
2494                                  &delayed_refs->href_root);
2495                         spin_unlock(&delayed_refs->lock);
2496                 } else {
2497                         actual_count++;
2498                         ref->in_tree = 0;
2499                         rb_erase(&ref->rb_node, &locked_ref->ref_root);
2500                 }
2501                 atomic_dec(&delayed_refs->num_entries);
2502
2503                 if (!btrfs_delayed_ref_is_head(ref)) {
2504                         /*
2505                          * when we play the delayed ref, also correct the
2506                          * ref_mod on head
2507                          */
2508                         switch (ref->action) {
2509                         case BTRFS_ADD_DELAYED_REF:
2510                         case BTRFS_ADD_DELAYED_EXTENT:
2511                                 locked_ref->node.ref_mod -= ref->ref_mod;
2512                                 break;
2513                         case BTRFS_DROP_DELAYED_REF:
2514                                 locked_ref->node.ref_mod += ref->ref_mod;
2515                                 break;
2516                         default:
2517                                 WARN_ON(1);
2518                         }
2519                 }
2520                 spin_unlock(&locked_ref->lock);
2521
2522                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2523                                           must_insert_reserved);
2524
2525                 btrfs_free_delayed_extent_op(extent_op);
2526                 if (ret) {
2527                         locked_ref->processing = 0;
2528                         btrfs_delayed_ref_unlock(locked_ref);
2529                         btrfs_put_delayed_ref(ref);
2530                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2531                         return ret;
2532                 }
2533
2534                 /*
2535                  * If this node is a head, that means all the refs in this head
2536                  * have been dealt with, and we will pick the next head to deal
2537                  * with, so we must unlock the head and drop it from the cluster
2538                  * list before we release it.
2539                  */
2540                 if (btrfs_delayed_ref_is_head(ref)) {
2541                         if (locked_ref->is_data &&
2542                             locked_ref->total_ref_mod < 0) {
2543                                 spin_lock(&delayed_refs->lock);
2544                                 delayed_refs->pending_csums -= ref->num_bytes;
2545                                 spin_unlock(&delayed_refs->lock);
2546                         }
2547                         btrfs_delayed_ref_unlock(locked_ref);
2548                         locked_ref = NULL;
2549                 }
2550                 btrfs_put_delayed_ref(ref);
2551                 count++;
2552                 cond_resched();
2553         }
2554
2555         /*
2556          * We don't want to include ref heads since we can have empty ref heads
2557          * and those will drastically skew our runtime down since we just do
2558          * accounting, no actual extent tree updates.
2559          */
2560         if (actual_count > 0) {
2561                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2562                 u64 avg;
2563
2564                 /*
2565                  * We weigh the current average higher than our current runtime
2566                  * to avoid large swings in the average.
2567                  */
2568                 spin_lock(&delayed_refs->lock);
2569                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2570                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2571                 spin_unlock(&delayed_refs->lock);
2572         }
2573         return 0;
2574 }
2575
2576 #ifdef SCRAMBLE_DELAYED_REFS
2577 /*
2578  * Normally delayed refs get processed in ascending bytenr order. This
2579  * correlates in most cases to the order added. To expose dependencies on this
2580  * order, we start to process the tree in the middle instead of the beginning
2581  */
2582 static u64 find_middle(struct rb_root *root)
2583 {
2584         struct rb_node *n = root->rb_node;
2585         struct btrfs_delayed_ref_node *entry;
2586         int alt = 1;
2587         u64 middle;
2588         u64 first = 0, last = 0;
2589
2590         n = rb_first(root);
2591         if (n) {
2592                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2593                 first = entry->bytenr;
2594         }
2595         n = rb_last(root);
2596         if (n) {
2597                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2598                 last = entry->bytenr;
2599         }
2600         n = root->rb_node;
2601
2602         while (n) {
2603                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2604                 WARN_ON(!entry->in_tree);
2605
2606                 middle = entry->bytenr;
2607
2608                 if (alt)
2609                         n = n->rb_left;
2610                 else
2611                         n = n->rb_right;
2612
2613                 alt = 1 - alt;
2614         }
2615         return middle;
2616 }
2617 #endif
2618
2619 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2620 {
2621         u64 num_bytes;
2622
2623         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2624                              sizeof(struct btrfs_extent_inline_ref));
2625         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2626                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2627
2628         /*
2629          * We don't ever fill up leaves all the way so multiply by 2 just to be
2630          * closer to what we're really going to want to ouse.
2631          */
2632         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2633 }
2634
2635 /*
2636  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2637  * would require to store the csums for that many bytes.
2638  */
2639 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2640 {
2641         u64 csum_size;
2642         u64 num_csums_per_leaf;
2643         u64 num_csums;
2644
2645         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2646         num_csums_per_leaf = div64_u64(csum_size,
2647                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2648         num_csums = div64_u64(csum_bytes, root->sectorsize);
2649         num_csums += num_csums_per_leaf - 1;
2650         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2651         return num_csums;
2652 }
2653
2654 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2655                                        struct btrfs_root *root)
2656 {
2657         struct btrfs_block_rsv *global_rsv;
2658         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2659         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2660         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2661         u64 num_bytes, num_dirty_bgs_bytes;
2662         int ret = 0;
2663
2664         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2665         num_heads = heads_to_leaves(root, num_heads);
2666         if (num_heads > 1)
2667                 num_bytes += (num_heads - 1) * root->nodesize;
2668         num_bytes <<= 1;
2669         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2670         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2671                                                              num_dirty_bgs);
2672         global_rsv = &root->fs_info->global_block_rsv;
2673
2674         /*
2675          * If we can't allocate any more chunks lets make sure we have _lots_ of
2676          * wiggle room since running delayed refs can create more delayed refs.
2677          */
2678         if (global_rsv->space_info->full) {
2679                 num_dirty_bgs_bytes <<= 1;
2680                 num_bytes <<= 1;
2681         }
2682
2683         spin_lock(&global_rsv->lock);
2684         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2685                 ret = 1;
2686         spin_unlock(&global_rsv->lock);
2687         return ret;
2688 }
2689
2690 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2691                                        struct btrfs_root *root)
2692 {
2693         struct btrfs_fs_info *fs_info = root->fs_info;
2694         u64 num_entries =
2695                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2696         u64 avg_runtime;
2697         u64 val;
2698
2699         smp_mb();
2700         avg_runtime = fs_info->avg_delayed_ref_runtime;
2701         val = num_entries * avg_runtime;
2702         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2703                 return 1;
2704         if (val >= NSEC_PER_SEC / 2)
2705                 return 2;
2706
2707         return btrfs_check_space_for_delayed_refs(trans, root);
2708 }
2709
2710 struct async_delayed_refs {
2711         struct btrfs_root *root;
2712         int count;
2713         int error;
2714         int sync;
2715         struct completion wait;
2716         struct btrfs_work work;
2717 };
2718
2719 static void delayed_ref_async_start(struct btrfs_work *work)
2720 {
2721         struct async_delayed_refs *async;
2722         struct btrfs_trans_handle *trans;
2723         int ret;
2724
2725         async = container_of(work, struct async_delayed_refs, work);
2726
2727         trans = btrfs_join_transaction(async->root);
2728         if (IS_ERR(trans)) {
2729                 async->error = PTR_ERR(trans);
2730                 goto done;
2731         }
2732
2733         /*
2734          * trans->sync means that when we call end_transaciton, we won't
2735          * wait on delayed refs
2736          */
2737         trans->sync = true;
2738         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2739         if (ret)
2740                 async->error = ret;
2741
2742         ret = btrfs_end_transaction(trans, async->root);
2743         if (ret && !async->error)
2744                 async->error = ret;
2745 done:
2746         if (async->sync)
2747                 complete(&async->wait);
2748         else
2749                 kfree(async);
2750 }
2751
2752 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2753                                  unsigned long count, int wait)
2754 {
2755         struct async_delayed_refs *async;
2756         int ret;
2757
2758         async = kmalloc(sizeof(*async), GFP_NOFS);
2759         if (!async)
2760                 return -ENOMEM;
2761
2762         async->root = root->fs_info->tree_root;
2763         async->count = count;
2764         async->error = 0;
2765         if (wait)
2766                 async->sync = 1;
2767         else
2768                 async->sync = 0;
2769         init_completion(&async->wait);
2770
2771         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2772                         delayed_ref_async_start, NULL, NULL);
2773
2774         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2775
2776         if (wait) {
2777                 wait_for_completion(&async->wait);
2778                 ret = async->error;
2779                 kfree(async);
2780                 return ret;
2781         }
2782         return 0;
2783 }
2784
2785 /*
2786  * this starts processing the delayed reference count updates and
2787  * extent insertions we have queued up so far.  count can be
2788  * 0, which means to process everything in the tree at the start
2789  * of the run (but not newly added entries), or it can be some target
2790  * number you'd like to process.
2791  *
2792  * Returns 0 on success or if called with an aborted transaction
2793  * Returns <0 on error and aborts the transaction
2794  */
2795 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2796                            struct btrfs_root *root, unsigned long count)
2797 {
2798         struct rb_node *node;
2799         struct btrfs_delayed_ref_root *delayed_refs;
2800         struct btrfs_delayed_ref_head *head;
2801         int ret;
2802         int run_all = count == (unsigned long)-1;
2803
2804         /* We'll clean this up in btrfs_cleanup_transaction */
2805         if (trans->aborted)
2806                 return 0;
2807
2808         if (root == root->fs_info->extent_root)
2809                 root = root->fs_info->tree_root;
2810
2811         delayed_refs = &trans->transaction->delayed_refs;
2812         if (count == 0)
2813                 count = atomic_read(&delayed_refs->num_entries) * 2;
2814
2815 again:
2816 #ifdef SCRAMBLE_DELAYED_REFS
2817         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2818 #endif
2819         ret = __btrfs_run_delayed_refs(trans, root, count);
2820         if (ret < 0) {
2821                 btrfs_abort_transaction(trans, root, ret);
2822                 return ret;
2823         }
2824
2825         if (run_all) {
2826                 if (!list_empty(&trans->new_bgs))
2827                         btrfs_create_pending_block_groups(trans, root);
2828
2829                 spin_lock(&delayed_refs->lock);
2830                 node = rb_first(&delayed_refs->href_root);
2831                 if (!node) {
2832                         spin_unlock(&delayed_refs->lock);
2833                         goto out;
2834                 }
2835                 count = (unsigned long)-1;
2836
2837                 while (node) {
2838                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2839                                         href_node);
2840                         if (btrfs_delayed_ref_is_head(&head->node)) {
2841                                 struct btrfs_delayed_ref_node *ref;
2842
2843                                 ref = &head->node;
2844                                 atomic_inc(&ref->refs);
2845
2846                                 spin_unlock(&delayed_refs->lock);
2847                                 /*
2848                                  * Mutex was contended, block until it's
2849                                  * released and try again
2850                                  */
2851                                 mutex_lock(&head->mutex);
2852                                 mutex_unlock(&head->mutex);
2853
2854                                 btrfs_put_delayed_ref(ref);
2855                                 cond_resched();
2856                                 goto again;
2857                         } else {
2858                                 WARN_ON(1);
2859                         }
2860                         node = rb_next(node);
2861                 }
2862                 spin_unlock(&delayed_refs->lock);
2863                 cond_resched();
2864                 goto again;
2865         }
2866 out:
2867         ret = btrfs_delayed_qgroup_accounting(trans, root->fs_info);
2868         if (ret)
2869                 return ret;
2870         assert_qgroups_uptodate(trans);
2871         return 0;
2872 }
2873
2874 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2875                                 struct btrfs_root *root,
2876                                 u64 bytenr, u64 num_bytes, u64 flags,
2877                                 int level, int is_data)
2878 {
2879         struct btrfs_delayed_extent_op *extent_op;
2880         int ret;
2881
2882         extent_op = btrfs_alloc_delayed_extent_op();
2883         if (!extent_op)
2884                 return -ENOMEM;
2885
2886         extent_op->flags_to_set = flags;
2887         extent_op->update_flags = 1;
2888         extent_op->update_key = 0;
2889         extent_op->is_data = is_data ? 1 : 0;
2890         extent_op->level = level;
2891
2892         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2893                                           num_bytes, extent_op);
2894         if (ret)
2895                 btrfs_free_delayed_extent_op(extent_op);
2896         return ret;
2897 }
2898
2899 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2900                                       struct btrfs_root *root,
2901                                       struct btrfs_path *path,
2902                                       u64 objectid, u64 offset, u64 bytenr)
2903 {
2904         struct btrfs_delayed_ref_head *head;
2905         struct btrfs_delayed_ref_node *ref;
2906         struct btrfs_delayed_data_ref *data_ref;
2907         struct btrfs_delayed_ref_root *delayed_refs;
2908         struct rb_node *node;
2909         int ret = 0;
2910
2911         delayed_refs = &trans->transaction->delayed_refs;
2912         spin_lock(&delayed_refs->lock);
2913         head = btrfs_find_delayed_ref_head(trans, bytenr);
2914         if (!head) {
2915                 spin_unlock(&delayed_refs->lock);
2916                 return 0;
2917         }
2918
2919         if (!mutex_trylock(&head->mutex)) {
2920                 atomic_inc(&head->node.refs);
2921                 spin_unlock(&delayed_refs->lock);
2922
2923                 btrfs_release_path(path);
2924
2925                 /*
2926                  * Mutex was contended, block until it's released and let
2927                  * caller try again
2928                  */
2929                 mutex_lock(&head->mutex);
2930                 mutex_unlock(&head->mutex);
2931                 btrfs_put_delayed_ref(&head->node);
2932                 return -EAGAIN;
2933         }
2934         spin_unlock(&delayed_refs->lock);
2935
2936         spin_lock(&head->lock);
2937         node = rb_first(&head->ref_root);
2938         while (node) {
2939                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2940                 node = rb_next(node);
2941
2942                 /* If it's a shared ref we know a cross reference exists */
2943                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2944                         ret = 1;
2945                         break;
2946                 }
2947
2948                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2949
2950                 /*
2951                  * If our ref doesn't match the one we're currently looking at
2952                  * then we have a cross reference.
2953                  */
2954                 if (data_ref->root != root->root_key.objectid ||
2955                     data_ref->objectid != objectid ||
2956                     data_ref->offset != offset) {
2957                         ret = 1;
2958                         break;
2959                 }
2960         }
2961         spin_unlock(&head->lock);
2962         mutex_unlock(&head->mutex);
2963         return ret;
2964 }
2965
2966 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2967                                         struct btrfs_root *root,
2968                                         struct btrfs_path *path,
2969                                         u64 objectid, u64 offset, u64 bytenr)
2970 {
2971         struct btrfs_root *extent_root = root->fs_info->extent_root;
2972         struct extent_buffer *leaf;
2973         struct btrfs_extent_data_ref *ref;
2974         struct btrfs_extent_inline_ref *iref;
2975         struct btrfs_extent_item *ei;
2976         struct btrfs_key key;
2977         u32 item_size;
2978         int ret;
2979
2980         key.objectid = bytenr;
2981         key.offset = (u64)-1;
2982         key.type = BTRFS_EXTENT_ITEM_KEY;
2983
2984         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2985         if (ret < 0)
2986                 goto out;
2987         BUG_ON(ret == 0); /* Corruption */
2988
2989         ret = -ENOENT;
2990         if (path->slots[0] == 0)
2991                 goto out;
2992
2993         path->slots[0]--;
2994         leaf = path->nodes[0];
2995         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2996
2997         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2998                 goto out;
2999
3000         ret = 1;
3001         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3002 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3003         if (item_size < sizeof(*ei)) {
3004                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3005                 goto out;
3006         }
3007 #endif
3008         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3009
3010         if (item_size != sizeof(*ei) +
3011             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3012                 goto out;
3013
3014         if (btrfs_extent_generation(leaf, ei) <=
3015             btrfs_root_last_snapshot(&root->root_item))
3016                 goto out;
3017
3018         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3019         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3020             BTRFS_EXTENT_DATA_REF_KEY)
3021                 goto out;
3022
3023         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3024         if (btrfs_extent_refs(leaf, ei) !=
3025             btrfs_extent_data_ref_count(leaf, ref) ||
3026             btrfs_extent_data_ref_root(leaf, ref) !=
3027             root->root_key.objectid ||
3028             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3029             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3030                 goto out;
3031
3032         ret = 0;
3033 out:
3034         return ret;
3035 }
3036
3037 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3038                           struct btrfs_root *root,
3039                           u64 objectid, u64 offset, u64 bytenr)
3040 {
3041         struct btrfs_path *path;
3042         int ret;
3043         int ret2;
3044
3045         path = btrfs_alloc_path();
3046         if (!path)
3047                 return -ENOENT;
3048
3049         do {
3050                 ret = check_committed_ref(trans, root, path, objectid,
3051                                           offset, bytenr);
3052                 if (ret && ret != -ENOENT)
3053                         goto out;
3054
3055                 ret2 = check_delayed_ref(trans, root, path, objectid,
3056                                          offset, bytenr);
3057         } while (ret2 == -EAGAIN);
3058
3059         if (ret2 && ret2 != -ENOENT) {
3060                 ret = ret2;
3061                 goto out;
3062         }
3063
3064         if (ret != -ENOENT || ret2 != -ENOENT)
3065                 ret = 0;
3066 out:
3067         btrfs_free_path(path);
3068         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3069                 WARN_ON(ret > 0);
3070         return ret;
3071 }
3072
3073 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3074                            struct btrfs_root *root,
3075                            struct extent_buffer *buf,
3076                            int full_backref, int inc)
3077 {
3078         u64 bytenr;
3079         u64 num_bytes;
3080         u64 parent;
3081         u64 ref_root;
3082         u32 nritems;
3083         struct btrfs_key key;
3084         struct btrfs_file_extent_item *fi;
3085         int i;
3086         int level;
3087         int ret = 0;
3088         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3089                             u64, u64, u64, u64, u64, u64, int);
3090
3091
3092         if (btrfs_test_is_dummy_root(root))
3093                 return 0;
3094
3095         ref_root = btrfs_header_owner(buf);
3096         nritems = btrfs_header_nritems(buf);
3097         level = btrfs_header_level(buf);
3098
3099         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3100                 return 0;
3101
3102         if (inc)
3103                 process_func = btrfs_inc_extent_ref;
3104         else
3105                 process_func = btrfs_free_extent;
3106
3107         if (full_backref)
3108                 parent = buf->start;
3109         else
3110                 parent = 0;
3111
3112         for (i = 0; i < nritems; i++) {
3113                 if (level == 0) {
3114                         btrfs_item_key_to_cpu(buf, &key, i);
3115                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3116                                 continue;
3117                         fi = btrfs_item_ptr(buf, i,
3118                                             struct btrfs_file_extent_item);
3119                         if (btrfs_file_extent_type(buf, fi) ==
3120                             BTRFS_FILE_EXTENT_INLINE)
3121                                 continue;
3122                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3123                         if (bytenr == 0)
3124                                 continue;
3125
3126                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3127                         key.offset -= btrfs_file_extent_offset(buf, fi);
3128                         ret = process_func(trans, root, bytenr, num_bytes,
3129                                            parent, ref_root, key.objectid,
3130                                            key.offset, 1);
3131                         if (ret)
3132                                 goto fail;
3133                 } else {
3134                         bytenr = btrfs_node_blockptr(buf, i);
3135                         num_bytes = root->nodesize;
3136                         ret = process_func(trans, root, bytenr, num_bytes,
3137                                            parent, ref_root, level - 1, 0,
3138                                            1);
3139                         if (ret)
3140                                 goto fail;
3141                 }
3142         }
3143         return 0;
3144 fail:
3145         return ret;
3146 }
3147
3148 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3149                   struct extent_buffer *buf, int full_backref)
3150 {
3151         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3152 }
3153
3154 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3155                   struct extent_buffer *buf, int full_backref)
3156 {
3157         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3158 }
3159
3160 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3161                                  struct btrfs_root *root,
3162                                  struct btrfs_path *path,
3163                                  struct btrfs_block_group_cache *cache)
3164 {
3165         int ret;
3166         struct btrfs_root *extent_root = root->fs_info->extent_root;
3167         unsigned long bi;
3168         struct extent_buffer *leaf;
3169
3170         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3171         if (ret) {
3172                 if (ret > 0)
3173                         ret = -ENOENT;
3174                 goto fail;
3175         }
3176
3177         leaf = path->nodes[0];
3178         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3179         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3180         btrfs_mark_buffer_dirty(leaf);
3181 fail:
3182         btrfs_release_path(path);
3183         if (ret)
3184                 btrfs_abort_transaction(trans, root, ret);
3185         return ret;
3186
3187 }
3188
3189 static struct btrfs_block_group_cache *
3190 next_block_group(struct btrfs_root *root,
3191                  struct btrfs_block_group_cache *cache)
3192 {
3193         struct rb_node *node;
3194
3195         spin_lock(&root->fs_info->block_group_cache_lock);
3196
3197         /* If our block group was removed, we need a full search. */
3198         if (RB_EMPTY_NODE(&cache->cache_node)) {
3199                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3200
3201                 spin_unlock(&root->fs_info->block_group_cache_lock);
3202                 btrfs_put_block_group(cache);
3203                 cache = btrfs_lookup_first_block_group(root->fs_info,
3204                                                        next_bytenr);
3205                 return cache;
3206         }
3207         node = rb_next(&cache->cache_node);
3208         btrfs_put_block_group(cache);
3209         if (node) {
3210                 cache = rb_entry(node, struct btrfs_block_group_cache,
3211                                  cache_node);
3212                 btrfs_get_block_group(cache);
3213         } else
3214                 cache = NULL;
3215         spin_unlock(&root->fs_info->block_group_cache_lock);
3216         return cache;
3217 }
3218
3219 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3220                             struct btrfs_trans_handle *trans,
3221                             struct btrfs_path *path)
3222 {
3223         struct btrfs_root *root = block_group->fs_info->tree_root;
3224         struct inode *inode = NULL;
3225         u64 alloc_hint = 0;
3226         int dcs = BTRFS_DC_ERROR;
3227         u64 num_pages = 0;
3228         int retries = 0;
3229         int ret = 0;
3230
3231         /*
3232          * If this block group is smaller than 100 megs don't bother caching the
3233          * block group.
3234          */
3235         if (block_group->key.offset < (100 * 1024 * 1024)) {
3236                 spin_lock(&block_group->lock);
3237                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3238                 spin_unlock(&block_group->lock);
3239                 return 0;
3240         }
3241
3242         if (trans->aborted)
3243                 return 0;
3244 again:
3245         inode = lookup_free_space_inode(root, block_group, path);
3246         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3247                 ret = PTR_ERR(inode);
3248                 btrfs_release_path(path);
3249                 goto out;
3250         }
3251
3252         if (IS_ERR(inode)) {
3253                 BUG_ON(retries);
3254                 retries++;
3255
3256                 if (block_group->ro)
3257                         goto out_free;
3258
3259                 ret = create_free_space_inode(root, trans, block_group, path);
3260                 if (ret)
3261                         goto out_free;
3262                 goto again;
3263         }
3264
3265         /* We've already setup this transaction, go ahead and exit */
3266         if (block_group->cache_generation == trans->transid &&
3267             i_size_read(inode)) {
3268                 dcs = BTRFS_DC_SETUP;
3269                 goto out_put;
3270         }
3271
3272         /*
3273          * We want to set the generation to 0, that way if anything goes wrong
3274          * from here on out we know not to trust this cache when we load up next
3275          * time.
3276          */
3277         BTRFS_I(inode)->generation = 0;
3278         ret = btrfs_update_inode(trans, root, inode);
3279         if (ret) {
3280                 /*
3281                  * So theoretically we could recover from this, simply set the
3282                  * super cache generation to 0 so we know to invalidate the
3283                  * cache, but then we'd have to keep track of the block groups
3284                  * that fail this way so we know we _have_ to reset this cache
3285                  * before the next commit or risk reading stale cache.  So to
3286                  * limit our exposure to horrible edge cases lets just abort the
3287                  * transaction, this only happens in really bad situations
3288                  * anyway.
3289                  */
3290                 btrfs_abort_transaction(trans, root, ret);
3291                 goto out_put;
3292         }
3293         WARN_ON(ret);
3294
3295         if (i_size_read(inode) > 0) {
3296                 ret = btrfs_check_trunc_cache_free_space(root,
3297                                         &root->fs_info->global_block_rsv);
3298                 if (ret)
3299                         goto out_put;
3300
3301                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3302                 if (ret)
3303                         goto out_put;
3304         }
3305
3306         spin_lock(&block_group->lock);
3307         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3308             !btrfs_test_opt(root, SPACE_CACHE) ||
3309             block_group->delalloc_bytes) {
3310                 /*
3311                  * don't bother trying to write stuff out _if_
3312                  * a) we're not cached,
3313                  * b) we're with nospace_cache mount option.
3314                  */
3315                 dcs = BTRFS_DC_WRITTEN;
3316                 spin_unlock(&block_group->lock);
3317                 goto out_put;
3318         }
3319         spin_unlock(&block_group->lock);
3320
3321         /*
3322          * Try to preallocate enough space based on how big the block group is.
3323          * Keep in mind this has to include any pinned space which could end up
3324          * taking up quite a bit since it's not folded into the other space
3325          * cache.
3326          */
3327         num_pages = div_u64(block_group->key.offset, 256 * 1024 * 1024);
3328         if (!num_pages)
3329                 num_pages = 1;
3330
3331         num_pages *= 16;
3332         num_pages *= PAGE_CACHE_SIZE;
3333
3334         ret = btrfs_check_data_free_space(inode, num_pages, num_pages);
3335         if (ret)
3336                 goto out_put;
3337
3338         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3339                                               num_pages, num_pages,
3340                                               &alloc_hint);
3341         if (!ret)
3342                 dcs = BTRFS_DC_SETUP;
3343         btrfs_free_reserved_data_space(inode, num_pages);
3344
3345 out_put:
3346         iput(inode);
3347 out_free:
3348         btrfs_release_path(path);
3349 out:
3350         spin_lock(&block_group->lock);
3351         if (!ret && dcs == BTRFS_DC_SETUP)
3352                 block_group->cache_generation = trans->transid;
3353         block_group->disk_cache_state = dcs;
3354         spin_unlock(&block_group->lock);
3355
3356         return ret;
3357 }
3358
3359 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3360                             struct btrfs_root *root)
3361 {
3362         struct btrfs_block_group_cache *cache, *tmp;
3363         struct btrfs_transaction *cur_trans = trans->transaction;
3364         struct btrfs_path *path;
3365
3366         if (list_empty(&cur_trans->dirty_bgs) ||
3367             !btrfs_test_opt(root, SPACE_CACHE))
3368                 return 0;
3369
3370         path = btrfs_alloc_path();
3371         if (!path)
3372                 return -ENOMEM;
3373
3374         /* Could add new block groups, use _safe just in case */
3375         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3376                                  dirty_list) {
3377                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3378                         cache_save_setup(cache, trans, path);
3379         }
3380
3381         btrfs_free_path(path);
3382         return 0;
3383 }
3384
3385 /*
3386  * transaction commit does final block group cache writeback during a
3387  * critical section where nothing is allowed to change the FS.  This is
3388  * required in order for the cache to actually match the block group,
3389  * but can introduce a lot of latency into the commit.
3390  *
3391  * So, btrfs_start_dirty_block_groups is here to kick off block group
3392  * cache IO.  There's a chance we'll have to redo some of it if the
3393  * block group changes again during the commit, but it greatly reduces
3394  * the commit latency by getting rid of the easy block groups while
3395  * we're still allowing others to join the commit.
3396  */
3397 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3398                                    struct btrfs_root *root)
3399 {
3400         struct btrfs_block_group_cache *cache;
3401         struct btrfs_transaction *cur_trans = trans->transaction;
3402         int ret = 0;
3403         int should_put;
3404         struct btrfs_path *path = NULL;
3405         LIST_HEAD(dirty);
3406         struct list_head *io = &cur_trans->io_bgs;
3407         int num_started = 0;
3408         int loops = 0;
3409
3410         spin_lock(&cur_trans->dirty_bgs_lock);
3411         if (list_empty(&cur_trans->dirty_bgs)) {
3412                 spin_unlock(&cur_trans->dirty_bgs_lock);
3413                 return 0;
3414         }
3415         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3416         spin_unlock(&cur_trans->dirty_bgs_lock);
3417
3418 again:
3419         /*
3420          * make sure all the block groups on our dirty list actually
3421          * exist
3422          */
3423         btrfs_create_pending_block_groups(trans, root);
3424
3425         if (!path) {
3426                 path = btrfs_alloc_path();
3427                 if (!path)
3428                         return -ENOMEM;
3429         }
3430
3431         /*
3432          * cache_write_mutex is here only to save us from balance or automatic
3433          * removal of empty block groups deleting this block group while we are
3434          * writing out the cache
3435          */
3436         mutex_lock(&trans->transaction->cache_write_mutex);
3437         while (!list_empty(&dirty)) {
3438                 cache = list_first_entry(&dirty,
3439                                          struct btrfs_block_group_cache,
3440                                          dirty_list);
3441                 /*
3442                  * this can happen if something re-dirties a block
3443                  * group that is already under IO.  Just wait for it to
3444                  * finish and then do it all again
3445                  */
3446                 if (!list_empty(&cache->io_list)) {
3447                         list_del_init(&cache->io_list);
3448                         btrfs_wait_cache_io(root, trans, cache,
3449                                             &cache->io_ctl, path,
3450                                             cache->key.objectid);
3451                         btrfs_put_block_group(cache);
3452                 }
3453
3454
3455                 /*
3456                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3457                  * if it should update the cache_state.  Don't delete
3458                  * until after we wait.
3459                  *
3460                  * Since we're not running in the commit critical section
3461                  * we need the dirty_bgs_lock to protect from update_block_group
3462                  */
3463                 spin_lock(&cur_trans->dirty_bgs_lock);
3464                 list_del_init(&cache->dirty_list);
3465                 spin_unlock(&cur_trans->dirty_bgs_lock);
3466
3467                 should_put = 1;
3468
3469                 cache_save_setup(cache, trans, path);
3470
3471                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3472                         cache->io_ctl.inode = NULL;
3473                         ret = btrfs_write_out_cache(root, trans, cache, path);
3474                         if (ret == 0 && cache->io_ctl.inode) {
3475                                 num_started++;
3476                                 should_put = 0;
3477
3478                                 /*
3479                                  * the cache_write_mutex is protecting
3480                                  * the io_list
3481                                  */
3482                                 list_add_tail(&cache->io_list, io);
3483                         } else {
3484                                 /*
3485                                  * if we failed to write the cache, the
3486                                  * generation will be bad and life goes on
3487                                  */
3488                                 ret = 0;
3489                         }
3490                 }
3491                 if (!ret)
3492                         ret = write_one_cache_group(trans, root, path, cache);
3493
3494                 /* if its not on the io list, we need to put the block group */
3495                 if (should_put)
3496                         btrfs_put_block_group(cache);
3497
3498                 if (ret)
3499                         break;
3500
3501                 /*
3502                  * Avoid blocking other tasks for too long. It might even save
3503                  * us from writing caches for block groups that are going to be
3504                  * removed.
3505                  */
3506                 mutex_unlock(&trans->transaction->cache_write_mutex);
3507                 mutex_lock(&trans->transaction->cache_write_mutex);
3508         }
3509         mutex_unlock(&trans->transaction->cache_write_mutex);
3510
3511         /*
3512          * go through delayed refs for all the stuff we've just kicked off
3513          * and then loop back (just once)
3514          */
3515         ret = btrfs_run_delayed_refs(trans, root, 0);
3516         if (!ret && loops == 0) {
3517                 loops++;
3518                 spin_lock(&cur_trans->dirty_bgs_lock);
3519                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3520                 /*
3521                  * dirty_bgs_lock protects us from concurrent block group
3522                  * deletes too (not just cache_write_mutex).
3523                  */
3524                 if (!list_empty(&dirty)) {
3525                         spin_unlock(&cur_trans->dirty_bgs_lock);
3526                         goto again;
3527                 }
3528                 spin_unlock(&cur_trans->dirty_bgs_lock);
3529         }
3530
3531         btrfs_free_path(path);
3532         return ret;
3533 }
3534
3535 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3536                                    struct btrfs_root *root)
3537 {
3538         struct btrfs_block_group_cache *cache;
3539         struct btrfs_transaction *cur_trans = trans->transaction;
3540         int ret = 0;
3541         int should_put;
3542         struct btrfs_path *path;
3543         struct list_head *io = &cur_trans->io_bgs;
3544         int num_started = 0;
3545
3546         path = btrfs_alloc_path();
3547         if (!path)
3548                 return -ENOMEM;
3549
3550         /*
3551          * We don't need the lock here since we are protected by the transaction
3552          * commit.  We want to do the cache_save_setup first and then run the
3553          * delayed refs to make sure we have the best chance at doing this all
3554          * in one shot.
3555          */
3556         while (!list_empty(&cur_trans->dirty_bgs)) {
3557                 cache = list_first_entry(&cur_trans->dirty_bgs,
3558                                          struct btrfs_block_group_cache,
3559                                          dirty_list);
3560
3561                 /*
3562                  * this can happen if cache_save_setup re-dirties a block
3563                  * group that is already under IO.  Just wait for it to
3564                  * finish and then do it all again
3565                  */
3566                 if (!list_empty(&cache->io_list)) {
3567                         list_del_init(&cache->io_list);
3568                         btrfs_wait_cache_io(root, trans, cache,
3569                                             &cache->io_ctl, path,
3570                                             cache->key.objectid);
3571                         btrfs_put_block_group(cache);
3572                 }
3573
3574                 /*
3575                  * don't remove from the dirty list until after we've waited
3576                  * on any pending IO
3577                  */
3578                 list_del_init(&cache->dirty_list);
3579                 should_put = 1;
3580
3581                 cache_save_setup(cache, trans, path);
3582
3583                 if (!ret)
3584                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3585
3586                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3587                         cache->io_ctl.inode = NULL;
3588                         ret = btrfs_write_out_cache(root, trans, cache, path);
3589                         if (ret == 0 && cache->io_ctl.inode) {
3590                                 num_started++;
3591                                 should_put = 0;
3592                                 list_add_tail(&cache->io_list, io);
3593                         } else {
3594                                 /*
3595                                  * if we failed to write the cache, the
3596                                  * generation will be bad and life goes on
3597                                  */
3598                                 ret = 0;
3599                         }
3600                 }
3601                 if (!ret)
3602                         ret = write_one_cache_group(trans, root, path, cache);
3603
3604                 /* if its not on the io list, we need to put the block group */
3605                 if (should_put)
3606                         btrfs_put_block_group(cache);
3607         }
3608
3609         while (!list_empty(io)) {
3610                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3611                                          io_list);
3612                 list_del_init(&cache->io_list);
3613                 btrfs_wait_cache_io(root, trans, cache,
3614                                     &cache->io_ctl, path, cache->key.objectid);
3615                 btrfs_put_block_group(cache);
3616         }
3617
3618         btrfs_free_path(path);
3619         return ret;
3620 }
3621
3622 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3623 {
3624         struct btrfs_block_group_cache *block_group;
3625         int readonly = 0;
3626
3627         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3628         if (!block_group || block_group->ro)
3629                 readonly = 1;
3630         if (block_group)
3631                 btrfs_put_block_group(block_group);
3632         return readonly;
3633 }
3634
3635 static const char *alloc_name(u64 flags)
3636 {
3637         switch (flags) {
3638         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3639                 return "mixed";
3640         case BTRFS_BLOCK_GROUP_METADATA:
3641                 return "metadata";
3642         case BTRFS_BLOCK_GROUP_DATA:
3643                 return "data";
3644         case BTRFS_BLOCK_GROUP_SYSTEM:
3645                 return "system";
3646         default:
3647                 WARN_ON(1);
3648                 return "invalid-combination";
3649         };
3650 }
3651
3652 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3653                              u64 total_bytes, u64 bytes_used,
3654                              struct btrfs_space_info **space_info)
3655 {
3656         struct btrfs_space_info *found;
3657         int i;
3658         int factor;
3659         int ret;
3660
3661         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3662                      BTRFS_BLOCK_GROUP_RAID10))
3663                 factor = 2;
3664         else
3665                 factor = 1;
3666
3667         found = __find_space_info(info, flags);
3668         if (found) {
3669                 spin_lock(&found->lock);
3670                 found->total_bytes += total_bytes;
3671                 found->disk_total += total_bytes * factor;
3672                 found->bytes_used += bytes_used;
3673                 found->disk_used += bytes_used * factor;
3674                 found->full = 0;
3675                 spin_unlock(&found->lock);
3676                 *space_info = found;
3677                 return 0;
3678         }
3679         found = kzalloc(sizeof(*found), GFP_NOFS);
3680         if (!found)
3681                 return -ENOMEM;
3682
3683         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3684         if (ret) {
3685                 kfree(found);
3686                 return ret;
3687         }
3688
3689         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3690                 INIT_LIST_HEAD(&found->block_groups[i]);
3691         init_rwsem(&found->groups_sem);
3692         spin_lock_init(&found->lock);
3693         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3694         found->total_bytes = total_bytes;
3695         found->disk_total = total_bytes * factor;
3696         found->bytes_used = bytes_used;
3697         found->disk_used = bytes_used * factor;
3698         found->bytes_pinned = 0;
3699         found->bytes_reserved = 0;
3700         found->bytes_readonly = 0;
3701         found->bytes_may_use = 0;
3702         found->full = 0;
3703         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3704         found->chunk_alloc = 0;
3705         found->flush = 0;
3706         init_waitqueue_head(&found->wait);
3707         INIT_LIST_HEAD(&found->ro_bgs);
3708
3709         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3710                                     info->space_info_kobj, "%s",
3711                                     alloc_name(found->flags));
3712         if (ret) {
3713                 kfree(found);
3714                 return ret;
3715         }
3716
3717         *space_info = found;
3718         list_add_rcu(&found->list, &info->space_info);
3719         if (flags & BTRFS_BLOCK_GROUP_DATA)
3720                 info->data_sinfo = found;
3721
3722         return ret;
3723 }
3724
3725 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3726 {
3727         u64 extra_flags = chunk_to_extended(flags) &
3728                                 BTRFS_EXTENDED_PROFILE_MASK;
3729
3730         write_seqlock(&fs_info->profiles_lock);
3731         if (flags & BTRFS_BLOCK_GROUP_DATA)
3732                 fs_info->avail_data_alloc_bits |= extra_flags;
3733         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3734                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3735         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3736                 fs_info->avail_system_alloc_bits |= extra_flags;
3737         write_sequnlock(&fs_info->profiles_lock);
3738 }
3739
3740 /*
3741  * returns target flags in extended format or 0 if restripe for this
3742  * chunk_type is not in progress
3743  *
3744  * should be called with either volume_mutex or balance_lock held
3745  */
3746 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3747 {
3748         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3749         u64 target = 0;
3750
3751         if (!bctl)
3752                 return 0;
3753
3754         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3755             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3756                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3757         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3758                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3759                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3760         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3761                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3762                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3763         }
3764
3765         return target;
3766 }
3767
3768 /*
3769  * @flags: available profiles in extended format (see ctree.h)
3770  *
3771  * Returns reduced profile in chunk format.  If profile changing is in
3772  * progress (either running or paused) picks the target profile (if it's
3773  * already available), otherwise falls back to plain reducing.
3774  */
3775 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3776 {
3777         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3778         u64 target;
3779         u64 tmp;
3780
3781         /*
3782          * see if restripe for this chunk_type is in progress, if so
3783          * try to reduce to the target profile
3784          */
3785         spin_lock(&root->fs_info->balance_lock);
3786         target = get_restripe_target(root->fs_info, flags);
3787         if (target) {
3788                 /* pick target profile only if it's already available */
3789                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3790                         spin_unlock(&root->fs_info->balance_lock);
3791                         return extended_to_chunk(target);
3792                 }
3793         }
3794         spin_unlock(&root->fs_info->balance_lock);
3795
3796         /* First, mask out the RAID levels which aren't possible */
3797         if (num_devices == 1)
3798                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3799                            BTRFS_BLOCK_GROUP_RAID5);
3800         if (num_devices < 3)
3801                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3802         if (num_devices < 4)
3803                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3804
3805         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3806                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3807                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3808         flags &= ~tmp;
3809
3810         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3811                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3812         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3813                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3814         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3815                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3816         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3817                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3818         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3819                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3820
3821         return extended_to_chunk(flags | tmp);
3822 }
3823
3824 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3825 {
3826         unsigned seq;
3827         u64 flags;
3828
3829         do {
3830                 flags = orig_flags;
3831                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3832
3833                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3834                         flags |= root->fs_info->avail_data_alloc_bits;
3835                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3836                         flags |= root->fs_info->avail_system_alloc_bits;
3837                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3838                         flags |= root->fs_info->avail_metadata_alloc_bits;
3839         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3840
3841         return btrfs_reduce_alloc_profile(root, flags);
3842 }
3843
3844 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3845 {
3846         u64 flags;
3847         u64 ret;
3848
3849         if (data)
3850                 flags = BTRFS_BLOCK_GROUP_DATA;
3851         else if (root == root->fs_info->chunk_root)
3852                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3853         else
3854                 flags = BTRFS_BLOCK_GROUP_METADATA;
3855
3856         ret = get_alloc_profile(root, flags);
3857         return ret;
3858 }
3859
3860 /*
3861  * This will check the space that the inode allocates from to make sure we have
3862  * enough space for bytes.
3863  */
3864 int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes)
3865 {
3866         struct btrfs_space_info *data_sinfo;
3867         struct btrfs_root *root = BTRFS_I(inode)->root;
3868         struct btrfs_fs_info *fs_info = root->fs_info;
3869         u64 used;
3870         int ret = 0;
3871         int need_commit = 2;
3872         int have_pinned_space;
3873
3874         /* make sure bytes are sectorsize aligned */
3875         bytes = ALIGN(bytes, root->sectorsize);
3876
3877         if (btrfs_is_free_space_inode(inode)) {
3878                 need_commit = 0;
3879                 ASSERT(current->journal_info);
3880         }
3881
3882         data_sinfo = fs_info->data_sinfo;
3883         if (!data_sinfo)
3884                 goto alloc;
3885
3886 again:
3887         /* make sure we have enough space to handle the data first */
3888         spin_lock(&data_sinfo->lock);
3889         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3890                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3891                 data_sinfo->bytes_may_use;
3892
3893         if (used + bytes > data_sinfo->total_bytes) {
3894                 struct btrfs_trans_handle *trans;
3895
3896                 /*
3897                  * if we don't have enough free bytes in this space then we need
3898                  * to alloc a new chunk.
3899                  */
3900                 if (!data_sinfo->full) {
3901                         u64 alloc_target;
3902
3903                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3904                         spin_unlock(&data_sinfo->lock);
3905 alloc:
3906                         alloc_target = btrfs_get_alloc_profile(root, 1);
3907                         /*
3908                          * It is ugly that we don't call nolock join
3909                          * transaction for the free space inode case here.
3910                          * But it is safe because we only do the data space
3911                          * reservation for the free space cache in the
3912                          * transaction context, the common join transaction
3913                          * just increase the counter of the current transaction
3914                          * handler, doesn't try to acquire the trans_lock of
3915                          * the fs.
3916                          */
3917                         trans = btrfs_join_transaction(root);
3918                         if (IS_ERR(trans))
3919                                 return PTR_ERR(trans);
3920
3921                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3922                                              alloc_target,
3923                                              CHUNK_ALLOC_NO_FORCE);
3924                         btrfs_end_transaction(trans, root);
3925                         if (ret < 0) {
3926                                 if (ret != -ENOSPC)
3927                                         return ret;
3928                                 else {
3929                                         have_pinned_space = 1;
3930                                         goto commit_trans;
3931                                 }
3932                         }
3933
3934                         if (!data_sinfo)
3935                                 data_sinfo = fs_info->data_sinfo;
3936
3937                         goto again;
3938                 }
3939
3940                 /*
3941                  * If we don't have enough pinned space to deal with this
3942                  * allocation, and no removed chunk in current transaction,
3943                  * don't bother committing the transaction.
3944                  */
3945                 have_pinned_space = percpu_counter_compare(
3946                         &data_sinfo->total_bytes_pinned,
3947                         used + bytes - data_sinfo->total_bytes);
3948                 spin_unlock(&data_sinfo->lock);
3949
3950                 /* commit the current transaction and try again */
3951 commit_trans:
3952                 if (need_commit &&
3953                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3954                         need_commit--;
3955
3956                         trans = btrfs_join_transaction(root);
3957                         if (IS_ERR(trans))
3958                                 return PTR_ERR(trans);
3959                         if (have_pinned_space >= 0 ||
3960                             trans->transaction->have_free_bgs ||
3961                             need_commit > 0) {
3962                                 ret = btrfs_commit_transaction(trans, root);
3963                                 if (ret)
3964                                         return ret;
3965                                 /*
3966                                  * make sure that all running delayed iput are
3967                                  * done
3968                                  */
3969                                 down_write(&root->fs_info->delayed_iput_sem);
3970                                 up_write(&root->fs_info->delayed_iput_sem);
3971                                 goto again;
3972                         } else {
3973                                 btrfs_end_transaction(trans, root);
3974                         }
3975                 }
3976
3977                 trace_btrfs_space_reservation(root->fs_info,
3978                                               "space_info:enospc",
3979                                               data_sinfo->flags, bytes, 1);
3980                 return -ENOSPC;
3981         }
3982         ret = btrfs_qgroup_reserve(root, write_bytes);
3983         if (ret)
3984                 goto out;
3985         data_sinfo->bytes_may_use += bytes;
3986         trace_btrfs_space_reservation(root->fs_info, "space_info",
3987                                       data_sinfo->flags, bytes, 1);
3988 out:
3989         spin_unlock(&data_sinfo->lock);
3990
3991         return ret;
3992 }
3993
3994 /*
3995  * Called if we need to clear a data reservation for this inode.
3996  */
3997 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3998 {
3999         struct btrfs_root *root = BTRFS_I(inode)->root;
4000         struct btrfs_space_info *data_sinfo;
4001
4002         /* make sure bytes are sectorsize aligned */
4003         bytes = ALIGN(bytes, root->sectorsize);
4004
4005         data_sinfo = root->fs_info->data_sinfo;
4006         spin_lock(&data_sinfo->lock);
4007         WARN_ON(data_sinfo->bytes_may_use < bytes);
4008         data_sinfo->bytes_may_use -= bytes;
4009         trace_btrfs_space_reservation(root->fs_info, "space_info",
4010                                       data_sinfo->flags, bytes, 0);
4011         spin_unlock(&data_sinfo->lock);
4012 }
4013
4014 static void force_metadata_allocation(struct btrfs_fs_info *info)
4015 {
4016         struct list_head *head = &info->space_info;
4017         struct btrfs_space_info *found;
4018
4019         rcu_read_lock();
4020         list_for_each_entry_rcu(found, head, list) {
4021                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4022                         found->force_alloc = CHUNK_ALLOC_FORCE;
4023         }
4024         rcu_read_unlock();
4025 }
4026
4027 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4028 {
4029         return (global->size << 1);
4030 }
4031
4032 static int should_alloc_chunk(struct btrfs_root *root,
4033                               struct btrfs_space_info *sinfo, int force)
4034 {
4035         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4036         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4037         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4038         u64 thresh;
4039
4040         if (force == CHUNK_ALLOC_FORCE)
4041                 return 1;
4042
4043         /*
4044          * We need to take into account the global rsv because for all intents
4045          * and purposes it's used space.  Don't worry about locking the
4046          * global_rsv, it doesn't change except when the transaction commits.
4047          */
4048         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4049                 num_allocated += calc_global_rsv_need_space(global_rsv);
4050
4051         /*
4052          * in limited mode, we want to have some free space up to
4053          * about 1% of the FS size.
4054          */
4055         if (force == CHUNK_ALLOC_LIMITED) {
4056                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4057                 thresh = max_t(u64, 64 * 1024 * 1024,
4058                                div_factor_fine(thresh, 1));
4059
4060                 if (num_bytes - num_allocated < thresh)
4061                         return 1;
4062         }
4063
4064         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
4065                 return 0;
4066         return 1;
4067 }
4068
4069 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
4070 {
4071         u64 num_dev;
4072
4073         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4074                     BTRFS_BLOCK_GROUP_RAID0 |
4075                     BTRFS_BLOCK_GROUP_RAID5 |
4076                     BTRFS_BLOCK_GROUP_RAID6))
4077                 num_dev = root->fs_info->fs_devices->rw_devices;
4078         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4079                 num_dev = 2;
4080         else
4081                 num_dev = 1;    /* DUP or single */
4082
4083         /* metadata for updaing devices and chunk tree */
4084         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
4085 }
4086
4087 static void check_system_chunk(struct btrfs_trans_handle *trans,
4088                                struct btrfs_root *root, u64 type)
4089 {
4090         struct btrfs_space_info *info;
4091         u64 left;
4092         u64 thresh;
4093
4094         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4095         spin_lock(&info->lock);
4096         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4097                 info->bytes_reserved - info->bytes_readonly;
4098         spin_unlock(&info->lock);
4099
4100         thresh = get_system_chunk_thresh(root, type);
4101         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4102                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4103                         left, thresh, type);
4104                 dump_space_info(info, 0, 0);
4105         }
4106
4107         if (left < thresh) {
4108                 u64 flags;
4109
4110                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4111                 btrfs_alloc_chunk(trans, root, flags);
4112         }
4113 }
4114
4115 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4116                           struct btrfs_root *extent_root, u64 flags, int force)
4117 {
4118         struct btrfs_space_info *space_info;
4119         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4120         int wait_for_alloc = 0;
4121         int ret = 0;
4122
4123         /* Don't re-enter if we're already allocating a chunk */
4124         if (trans->allocating_chunk)
4125                 return -ENOSPC;
4126
4127         space_info = __find_space_info(extent_root->fs_info, flags);
4128         if (!space_info) {
4129                 ret = update_space_info(extent_root->fs_info, flags,
4130                                         0, 0, &space_info);
4131                 BUG_ON(ret); /* -ENOMEM */
4132         }
4133         BUG_ON(!space_info); /* Logic error */
4134
4135 again:
4136         spin_lock(&space_info->lock);
4137         if (force < space_info->force_alloc)
4138                 force = space_info->force_alloc;
4139         if (space_info->full) {
4140                 if (should_alloc_chunk(extent_root, space_info, force))
4141                         ret = -ENOSPC;
4142                 else
4143                         ret = 0;
4144                 spin_unlock(&space_info->lock);
4145                 return ret;
4146         }
4147
4148         if (!should_alloc_chunk(extent_root, space_info, force)) {
4149                 spin_unlock(&space_info->lock);
4150                 return 0;
4151         } else if (space_info->chunk_alloc) {
4152                 wait_for_alloc = 1;
4153         } else {
4154                 space_info->chunk_alloc = 1;
4155         }
4156
4157         spin_unlock(&space_info->lock);
4158
4159         mutex_lock(&fs_info->chunk_mutex);
4160
4161         /*
4162          * The chunk_mutex is held throughout the entirety of a chunk
4163          * allocation, so once we've acquired the chunk_mutex we know that the
4164          * other guy is done and we need to recheck and see if we should
4165          * allocate.
4166          */
4167         if (wait_for_alloc) {
4168                 mutex_unlock(&fs_info->chunk_mutex);
4169                 wait_for_alloc = 0;
4170                 goto again;
4171         }
4172
4173         trans->allocating_chunk = true;
4174
4175         /*
4176          * If we have mixed data/metadata chunks we want to make sure we keep
4177          * allocating mixed chunks instead of individual chunks.
4178          */
4179         if (btrfs_mixed_space_info(space_info))
4180                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4181
4182         /*
4183          * if we're doing a data chunk, go ahead and make sure that
4184          * we keep a reasonable number of metadata chunks allocated in the
4185          * FS as well.
4186          */
4187         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4188                 fs_info->data_chunk_allocations++;
4189                 if (!(fs_info->data_chunk_allocations %
4190                       fs_info->metadata_ratio))
4191                         force_metadata_allocation(fs_info);
4192         }
4193
4194         /*
4195          * Check if we have enough space in SYSTEM chunk because we may need
4196          * to update devices.
4197          */
4198         check_system_chunk(trans, extent_root, flags);
4199
4200         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4201         trans->allocating_chunk = false;
4202
4203         spin_lock(&space_info->lock);
4204         if (ret < 0 && ret != -ENOSPC)
4205                 goto out;
4206         if (ret)
4207                 space_info->full = 1;
4208         else
4209                 ret = 1;
4210
4211         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4212 out:
4213         space_info->chunk_alloc = 0;
4214         spin_unlock(&space_info->lock);
4215         mutex_unlock(&fs_info->chunk_mutex);
4216         return ret;
4217 }
4218
4219 static int can_overcommit(struct btrfs_root *root,
4220                           struct btrfs_space_info *space_info, u64 bytes,
4221                           enum btrfs_reserve_flush_enum flush)
4222 {
4223         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4224         u64 profile = btrfs_get_alloc_profile(root, 0);
4225         u64 space_size;
4226         u64 avail;
4227         u64 used;
4228
4229         used = space_info->bytes_used + space_info->bytes_reserved +
4230                 space_info->bytes_pinned + space_info->bytes_readonly;
4231
4232         /*
4233          * We only want to allow over committing if we have lots of actual space
4234          * free, but if we don't have enough space to handle the global reserve
4235          * space then we could end up having a real enospc problem when trying
4236          * to allocate a chunk or some other such important allocation.
4237          */
4238         spin_lock(&global_rsv->lock);
4239         space_size = calc_global_rsv_need_space(global_rsv);
4240         spin_unlock(&global_rsv->lock);
4241         if (used + space_size >= space_info->total_bytes)
4242                 return 0;
4243
4244         used += space_info->bytes_may_use;
4245
4246         spin_lock(&root->fs_info->free_chunk_lock);
4247         avail = root->fs_info->free_chunk_space;
4248         spin_unlock(&root->fs_info->free_chunk_lock);
4249
4250         /*
4251          * If we have dup, raid1 or raid10 then only half of the free
4252          * space is actually useable.  For raid56, the space info used
4253          * doesn't include the parity drive, so we don't have to
4254          * change the math
4255          */
4256         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4257                        BTRFS_BLOCK_GROUP_RAID1 |
4258                        BTRFS_BLOCK_GROUP_RAID10))
4259                 avail >>= 1;
4260
4261         /*
4262          * If we aren't flushing all things, let us overcommit up to
4263          * 1/2th of the space. If we can flush, don't let us overcommit
4264          * too much, let it overcommit up to 1/8 of the space.
4265          */
4266         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4267                 avail >>= 3;
4268         else
4269                 avail >>= 1;
4270
4271         if (used + bytes < space_info->total_bytes + avail)
4272                 return 1;
4273         return 0;
4274 }
4275
4276 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4277                                          unsigned long nr_pages, int nr_items)
4278 {
4279         struct super_block *sb = root->fs_info->sb;
4280
4281         if (down_read_trylock(&sb->s_umount)) {
4282                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4283                 up_read(&sb->s_umount);
4284         } else {
4285                 /*
4286                  * We needn't worry the filesystem going from r/w to r/o though
4287                  * we don't acquire ->s_umount mutex, because the filesystem
4288                  * should guarantee the delalloc inodes list be empty after
4289                  * the filesystem is readonly(all dirty pages are written to
4290                  * the disk).
4291                  */
4292                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4293                 if (!current->journal_info)
4294                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4295         }
4296 }
4297
4298 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4299 {
4300         u64 bytes;
4301         int nr;
4302
4303         bytes = btrfs_calc_trans_metadata_size(root, 1);
4304         nr = (int)div64_u64(to_reclaim, bytes);
4305         if (!nr)
4306                 nr = 1;
4307         return nr;
4308 }
4309
4310 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4311
4312 /*
4313  * shrink metadata reservation for delalloc
4314  */
4315 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4316                             bool wait_ordered)
4317 {
4318         struct btrfs_block_rsv *block_rsv;
4319         struct btrfs_space_info *space_info;
4320         struct btrfs_trans_handle *trans;
4321         u64 delalloc_bytes;
4322         u64 max_reclaim;
4323         long time_left;
4324         unsigned long nr_pages;
4325         int loops;
4326         int items;
4327         enum btrfs_reserve_flush_enum flush;
4328
4329         /* Calc the number of the pages we need flush for space reservation */
4330         items = calc_reclaim_items_nr(root, to_reclaim);
4331         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4332
4333         trans = (struct btrfs_trans_handle *)current->journal_info;
4334         block_rsv = &root->fs_info->delalloc_block_rsv;
4335         space_info = block_rsv->space_info;
4336
4337         delalloc_bytes = percpu_counter_sum_positive(
4338                                                 &root->fs_info->delalloc_bytes);
4339         if (delalloc_bytes == 0) {
4340                 if (trans)
4341                         return;
4342                 if (wait_ordered)
4343                         btrfs_wait_ordered_roots(root->fs_info, items);
4344                 return;
4345         }
4346
4347         loops = 0;
4348         while (delalloc_bytes && loops < 3) {
4349                 max_reclaim = min(delalloc_bytes, to_reclaim);
4350                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4351                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4352                 /*
4353                  * We need to wait for the async pages to actually start before
4354                  * we do anything.
4355                  */
4356                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4357                 if (!max_reclaim)
4358                         goto skip_async;
4359
4360                 if (max_reclaim <= nr_pages)
4361                         max_reclaim = 0;
4362                 else
4363                         max_reclaim -= nr_pages;
4364
4365                 wait_event(root->fs_info->async_submit_wait,
4366                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4367                            (int)max_reclaim);
4368 skip_async:
4369                 if (!trans)
4370                         flush = BTRFS_RESERVE_FLUSH_ALL;
4371                 else
4372                         flush = BTRFS_RESERVE_NO_FLUSH;
4373                 spin_lock(&space_info->lock);
4374                 if (can_overcommit(root, space_info, orig, flush)) {
4375                         spin_unlock(&space_info->lock);
4376                         break;
4377                 }
4378                 spin_unlock(&space_info->lock);
4379
4380                 loops++;
4381                 if (wait_ordered && !trans) {
4382                         btrfs_wait_ordered_roots(root->fs_info, items);
4383                 } else {
4384                         time_left = schedule_timeout_killable(1);
4385                         if (time_left)
4386                                 break;
4387                 }
4388                 delalloc_bytes = percpu_counter_sum_positive(
4389                                                 &root->fs_info->delalloc_bytes);
4390         }
4391 }
4392
4393 /**
4394  * maybe_commit_transaction - possibly commit the transaction if its ok to
4395  * @root - the root we're allocating for
4396  * @bytes - the number of bytes we want to reserve
4397  * @force - force the commit
4398  *
4399  * This will check to make sure that committing the transaction will actually
4400  * get us somewhere and then commit the transaction if it does.  Otherwise it
4401  * will return -ENOSPC.
4402  */
4403 static int may_commit_transaction(struct btrfs_root *root,
4404                                   struct btrfs_space_info *space_info,
4405                                   u64 bytes, int force)
4406 {
4407         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4408         struct btrfs_trans_handle *trans;
4409
4410         trans = (struct btrfs_trans_handle *)current->journal_info;
4411         if (trans)
4412                 return -EAGAIN;
4413
4414         if (force)
4415                 goto commit;
4416
4417         /* See if there is enough pinned space to make this reservation */
4418         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4419                                    bytes) >= 0)
4420                 goto commit;
4421
4422         /*
4423          * See if there is some space in the delayed insertion reservation for
4424          * this reservation.
4425          */
4426         if (space_info != delayed_rsv->space_info)
4427                 return -ENOSPC;
4428
4429         spin_lock(&delayed_rsv->lock);
4430         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4431                                    bytes - delayed_rsv->size) >= 0) {
4432                 spin_unlock(&delayed_rsv->lock);
4433                 return -ENOSPC;
4434         }
4435         spin_unlock(&delayed_rsv->lock);
4436
4437 commit:
4438         trans = btrfs_join_transaction(root);
4439         if (IS_ERR(trans))
4440                 return -ENOSPC;
4441
4442         return btrfs_commit_transaction(trans, root);
4443 }
4444
4445 enum flush_state {
4446         FLUSH_DELAYED_ITEMS_NR  =       1,
4447         FLUSH_DELAYED_ITEMS     =       2,
4448         FLUSH_DELALLOC          =       3,
4449         FLUSH_DELALLOC_WAIT     =       4,
4450         ALLOC_CHUNK             =       5,
4451         COMMIT_TRANS            =       6,
4452 };
4453
4454 static int flush_space(struct btrfs_root *root,
4455                        struct btrfs_space_info *space_info, u64 num_bytes,
4456                        u64 orig_bytes, int state)
4457 {
4458         struct btrfs_trans_handle *trans;
4459         int nr;
4460         int ret = 0;
4461
4462         switch (state) {
4463         case FLUSH_DELAYED_ITEMS_NR:
4464         case FLUSH_DELAYED_ITEMS:
4465                 if (state == FLUSH_DELAYED_ITEMS_NR)
4466                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4467                 else
4468                         nr = -1;
4469
4470                 trans = btrfs_join_transaction(root);
4471                 if (IS_ERR(trans)) {
4472                         ret = PTR_ERR(trans);
4473                         break;
4474                 }
4475                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4476                 btrfs_end_transaction(trans, root);
4477                 break;
4478         case FLUSH_DELALLOC:
4479         case FLUSH_DELALLOC_WAIT:
4480                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4481                                 state == FLUSH_DELALLOC_WAIT);
4482                 break;
4483         case ALLOC_CHUNK:
4484                 trans = btrfs_join_transaction(root);
4485                 if (IS_ERR(trans)) {
4486                         ret = PTR_ERR(trans);
4487                         break;
4488                 }
4489                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4490                                      btrfs_get_alloc_profile(root, 0),
4491                                      CHUNK_ALLOC_NO_FORCE);
4492                 btrfs_end_transaction(trans, root);
4493                 if (ret == -ENOSPC)
4494                         ret = 0;
4495                 break;
4496         case COMMIT_TRANS:
4497                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4498                 break;
4499         default:
4500                 ret = -ENOSPC;
4501                 break;
4502         }
4503
4504         return ret;
4505 }
4506
4507 static inline u64
4508 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4509                                  struct btrfs_space_info *space_info)
4510 {
4511         u64 used;
4512         u64 expected;
4513         u64 to_reclaim;
4514
4515         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4516                                 16 * 1024 * 1024);
4517         spin_lock(&space_info->lock);
4518         if (can_overcommit(root, space_info, to_reclaim,
4519                            BTRFS_RESERVE_FLUSH_ALL)) {
4520                 to_reclaim = 0;
4521                 goto out;
4522         }
4523
4524         used = space_info->bytes_used + space_info->bytes_reserved +
4525                space_info->bytes_pinned + space_info->bytes_readonly +
4526                space_info->bytes_may_use;
4527         if (can_overcommit(root, space_info, 1024 * 1024,
4528                            BTRFS_RESERVE_FLUSH_ALL))
4529                 expected = div_factor_fine(space_info->total_bytes, 95);
4530         else
4531                 expected = div_factor_fine(space_info->total_bytes, 90);
4532
4533         if (used > expected)
4534                 to_reclaim = used - expected;
4535         else
4536                 to_reclaim = 0;
4537         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4538                                      space_info->bytes_reserved);
4539 out:
4540         spin_unlock(&space_info->lock);
4541
4542         return to_reclaim;
4543 }
4544
4545 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4546                                         struct btrfs_fs_info *fs_info, u64 used)
4547 {
4548         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4549
4550         /* If we're just plain full then async reclaim just slows us down. */
4551         if (space_info->bytes_used >= thresh)
4552                 return 0;
4553
4554         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4555                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4556 }
4557
4558 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4559                                        struct btrfs_fs_info *fs_info,
4560                                        int flush_state)
4561 {
4562         u64 used;
4563
4564         spin_lock(&space_info->lock);
4565         /*
4566          * We run out of space and have not got any free space via flush_space,
4567          * so don't bother doing async reclaim.
4568          */
4569         if (flush_state > COMMIT_TRANS && space_info->full) {
4570                 spin_unlock(&space_info->lock);
4571                 return 0;
4572         }
4573
4574         used = space_info->bytes_used + space_info->bytes_reserved +
4575                space_info->bytes_pinned + space_info->bytes_readonly +
4576                space_info->bytes_may_use;
4577         if (need_do_async_reclaim(space_info, fs_info, used)) {
4578                 spin_unlock(&space_info->lock);
4579                 return 1;
4580         }
4581         spin_unlock(&space_info->lock);
4582
4583         return 0;
4584 }
4585
4586 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4587 {
4588         struct btrfs_fs_info *fs_info;
4589         struct btrfs_space_info *space_info;
4590         u64 to_reclaim;
4591         int flush_state;
4592
4593         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4594         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4595
4596         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4597                                                       space_info);
4598         if (!to_reclaim)
4599                 return;
4600
4601         flush_state = FLUSH_DELAYED_ITEMS_NR;
4602         do {
4603                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4604                             to_reclaim, flush_state);
4605                 flush_state++;
4606                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4607                                                  flush_state))
4608                         return;
4609         } while (flush_state < COMMIT_TRANS);
4610 }
4611
4612 void btrfs_init_async_reclaim_work(struct work_struct *work)
4613 {
4614         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4615 }
4616
4617 /**
4618  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4619  * @root - the root we're allocating for
4620  * @block_rsv - the block_rsv we're allocating for
4621  * @orig_bytes - the number of bytes we want
4622  * @flush - whether or not we can flush to make our reservation
4623  *
4624  * This will reserve orgi_bytes number of bytes from the space info associated
4625  * with the block_rsv.  If there is not enough space it will make an attempt to
4626  * flush out space to make room.  It will do this by flushing delalloc if
4627  * possible or committing the transaction.  If flush is 0 then no attempts to
4628  * regain reservations will be made and this will fail if there is not enough
4629  * space already.
4630  */
4631 static int reserve_metadata_bytes(struct btrfs_root *root,
4632                                   struct btrfs_block_rsv *block_rsv,
4633                                   u64 orig_bytes,
4634                                   enum btrfs_reserve_flush_enum flush)
4635 {
4636         struct btrfs_space_info *space_info = block_rsv->space_info;
4637         u64 used;
4638         u64 num_bytes = orig_bytes;
4639         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4640         int ret = 0;
4641         bool flushing = false;
4642
4643 again:
4644         ret = 0;
4645         spin_lock(&space_info->lock);
4646         /*
4647          * We only want to wait if somebody other than us is flushing and we
4648          * are actually allowed to flush all things.
4649          */
4650         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4651                space_info->flush) {
4652                 spin_unlock(&space_info->lock);
4653                 /*
4654                  * If we have a trans handle we can't wait because the flusher
4655                  * may have to commit the transaction, which would mean we would
4656                  * deadlock since we are waiting for the flusher to finish, but
4657                  * hold the current transaction open.
4658                  */
4659                 if (current->journal_info)
4660                         return -EAGAIN;
4661                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4662                 /* Must have been killed, return */
4663                 if (ret)
4664                         return -EINTR;
4665
4666                 spin_lock(&space_info->lock);
4667         }
4668
4669         ret = -ENOSPC;
4670         used = space_info->bytes_used + space_info->bytes_reserved +
4671                 space_info->bytes_pinned + space_info->bytes_readonly +
4672                 space_info->bytes_may_use;
4673
4674         /*
4675          * The idea here is that we've not already over-reserved the block group
4676          * then we can go ahead and save our reservation first and then start
4677          * flushing if we need to.  Otherwise if we've already overcommitted
4678          * lets start flushing stuff first and then come back and try to make
4679          * our reservation.
4680          */
4681         if (used <= space_info->total_bytes) {
4682                 if (used + orig_bytes <= space_info->total_bytes) {
4683                         space_info->bytes_may_use += orig_bytes;
4684                         trace_btrfs_space_reservation(root->fs_info,
4685                                 "space_info", space_info->flags, orig_bytes, 1);
4686                         ret = 0;
4687                 } else {
4688                         /*
4689                          * Ok set num_bytes to orig_bytes since we aren't
4690                          * overocmmitted, this way we only try and reclaim what
4691                          * we need.
4692                          */
4693                         num_bytes = orig_bytes;
4694                 }
4695         } else {
4696                 /*
4697                  * Ok we're over committed, set num_bytes to the overcommitted
4698                  * amount plus the amount of bytes that we need for this
4699                  * reservation.
4700                  */
4701                 num_bytes = used - space_info->total_bytes +
4702                         (orig_bytes * 2);
4703         }
4704
4705         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4706                 space_info->bytes_may_use += orig_bytes;
4707                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4708                                               space_info->flags, orig_bytes,
4709                                               1);
4710                 ret = 0;
4711         }
4712
4713         /*
4714          * Couldn't make our reservation, save our place so while we're trying
4715          * to reclaim space we can actually use it instead of somebody else
4716          * stealing it from us.
4717          *
4718          * We make the other tasks wait for the flush only when we can flush
4719          * all things.
4720          */
4721         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4722                 flushing = true;
4723                 space_info->flush = 1;
4724         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4725                 used += orig_bytes;
4726                 /*
4727                  * We will do the space reservation dance during log replay,
4728                  * which means we won't have fs_info->fs_root set, so don't do
4729                  * the async reclaim as we will panic.
4730                  */
4731                 if (!root->fs_info->log_root_recovering &&
4732                     need_do_async_reclaim(space_info, root->fs_info, used) &&
4733                     !work_busy(&root->fs_info->async_reclaim_work))
4734                         queue_work(system_unbound_wq,
4735                                    &root->fs_info->async_reclaim_work);
4736         }
4737         spin_unlock(&space_info->lock);
4738
4739         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4740                 goto out;
4741
4742         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4743                           flush_state);
4744         flush_state++;
4745
4746         /*
4747          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4748          * would happen. So skip delalloc flush.
4749          */
4750         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4751             (flush_state == FLUSH_DELALLOC ||
4752              flush_state == FLUSH_DELALLOC_WAIT))
4753                 flush_state = ALLOC_CHUNK;
4754
4755         if (!ret)
4756                 goto again;
4757         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4758                  flush_state < COMMIT_TRANS)
4759                 goto again;
4760         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4761                  flush_state <= COMMIT_TRANS)
4762                 goto again;
4763
4764 out:
4765         if (ret == -ENOSPC &&
4766             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4767                 struct btrfs_block_rsv *global_rsv =
4768                         &root->fs_info->global_block_rsv;
4769
4770                 if (block_rsv != global_rsv &&
4771                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4772                         ret = 0;
4773         }
4774         if (ret == -ENOSPC)
4775                 trace_btrfs_space_reservation(root->fs_info,
4776                                               "space_info:enospc",
4777                                               space_info->flags, orig_bytes, 1);
4778         if (flushing) {
4779                 spin_lock(&space_info->lock);
4780                 space_info->flush = 0;
4781                 wake_up_all(&space_info->wait);
4782                 spin_unlock(&space_info->lock);
4783         }
4784         return ret;
4785 }
4786
4787 static struct btrfs_block_rsv *get_block_rsv(
4788                                         const struct btrfs_trans_handle *trans,
4789                                         const struct btrfs_root *root)
4790 {
4791         struct btrfs_block_rsv *block_rsv = NULL;
4792
4793         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4794                 block_rsv = trans->block_rsv;
4795
4796         if (root == root->fs_info->csum_root && trans->adding_csums)
4797                 block_rsv = trans->block_rsv;
4798
4799         if (root == root->fs_info->uuid_root)
4800                 block_rsv = trans->block_rsv;
4801
4802         if (!block_rsv)
4803                 block_rsv = root->block_rsv;
4804
4805         if (!block_rsv)
4806                 block_rsv = &root->fs_info->empty_block_rsv;
4807
4808         return block_rsv;
4809 }
4810
4811 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4812                                u64 num_bytes)
4813 {
4814         int ret = -ENOSPC;
4815         spin_lock(&block_rsv->lock);
4816         if (block_rsv->reserved >= num_bytes) {
4817                 block_rsv->reserved -= num_bytes;
4818                 if (block_rsv->reserved < block_rsv->size)
4819                         block_rsv->full = 0;
4820                 ret = 0;
4821         }
4822         spin_unlock(&block_rsv->lock);
4823         return ret;
4824 }
4825
4826 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4827                                 u64 num_bytes, int update_size)
4828 {
4829         spin_lock(&block_rsv->lock);
4830         block_rsv->reserved += num_bytes;
4831         if (update_size)
4832                 block_rsv->size += num_bytes;
4833         else if (block_rsv->reserved >= block_rsv->size)
4834                 block_rsv->full = 1;
4835         spin_unlock(&block_rsv->lock);
4836 }
4837
4838 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4839                              struct btrfs_block_rsv *dest, u64 num_bytes,
4840                              int min_factor)
4841 {
4842         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4843         u64 min_bytes;
4844
4845         if (global_rsv->space_info != dest->space_info)
4846                 return -ENOSPC;
4847
4848         spin_lock(&global_rsv->lock);
4849         min_bytes = div_factor(global_rsv->size, min_factor);
4850         if (global_rsv->reserved < min_bytes + num_bytes) {
4851                 spin_unlock(&global_rsv->lock);
4852                 return -ENOSPC;
4853         }
4854         global_rsv->reserved -= num_bytes;
4855         if (global_rsv->reserved < global_rsv->size)
4856                 global_rsv->full = 0;
4857         spin_unlock(&global_rsv->lock);
4858
4859         block_rsv_add_bytes(dest, num_bytes, 1);
4860         return 0;
4861 }
4862
4863 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4864                                     struct btrfs_block_rsv *block_rsv,
4865                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4866 {
4867         struct btrfs_space_info *space_info = block_rsv->space_info;
4868
4869         spin_lock(&block_rsv->lock);
4870         if (num_bytes == (u64)-1)
4871                 num_bytes = block_rsv->size;
4872         block_rsv->size -= num_bytes;
4873         if (block_rsv->reserved >= block_rsv->size) {
4874                 num_bytes = block_rsv->reserved - block_rsv->size;
4875                 block_rsv->reserved = block_rsv->size;
4876                 block_rsv->full = 1;
4877         } else {
4878                 num_bytes = 0;
4879         }
4880         spin_unlock(&block_rsv->lock);
4881
4882         if (num_bytes > 0) {
4883                 if (dest) {
4884                         spin_lock(&dest->lock);
4885                         if (!dest->full) {
4886                                 u64 bytes_to_add;
4887
4888                                 bytes_to_add = dest->size - dest->reserved;
4889                                 bytes_to_add = min(num_bytes, bytes_to_add);
4890                                 dest->reserved += bytes_to_add;
4891                                 if (dest->reserved >= dest->size)
4892                                         dest->full = 1;
4893                                 num_bytes -= bytes_to_add;
4894                         }
4895                         spin_unlock(&dest->lock);
4896                 }
4897                 if (num_bytes) {
4898                         spin_lock(&space_info->lock);
4899                         space_info->bytes_may_use -= num_bytes;
4900                         trace_btrfs_space_reservation(fs_info, "space_info",
4901                                         space_info->flags, num_bytes, 0);
4902                         spin_unlock(&space_info->lock);
4903                 }
4904         }
4905 }
4906
4907 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4908                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4909 {
4910         int ret;
4911
4912         ret = block_rsv_use_bytes(src, num_bytes);
4913         if (ret)
4914                 return ret;
4915
4916         block_rsv_add_bytes(dst, num_bytes, 1);
4917         return 0;
4918 }
4919
4920 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4921 {
4922         memset(rsv, 0, sizeof(*rsv));
4923         spin_lock_init(&rsv->lock);
4924         rsv->type = type;
4925 }
4926
4927 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4928                                               unsigned short type)
4929 {
4930         struct btrfs_block_rsv *block_rsv;
4931         struct btrfs_fs_info *fs_info = root->fs_info;
4932
4933         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4934         if (!block_rsv)
4935                 return NULL;
4936
4937         btrfs_init_block_rsv(block_rsv, type);
4938         block_rsv->space_info = __find_space_info(fs_info,
4939                                                   BTRFS_BLOCK_GROUP_METADATA);
4940         return block_rsv;
4941 }
4942
4943 void btrfs_free_block_rsv(struct btrfs_root *root,
4944                           struct btrfs_block_rsv *rsv)
4945 {
4946         if (!rsv)
4947                 return;
4948         btrfs_block_rsv_release(root, rsv, (u64)-1);
4949         kfree(rsv);
4950 }
4951
4952 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
4953 {
4954         kfree(rsv);
4955 }
4956
4957 int btrfs_block_rsv_add(struct btrfs_root *root,
4958                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4959                         enum btrfs_reserve_flush_enum flush)
4960 {
4961         int ret;
4962
4963         if (num_bytes == 0)
4964                 return 0;
4965
4966         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4967         if (!ret) {
4968                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4969                 return 0;
4970         }
4971
4972         return ret;
4973 }
4974
4975 int btrfs_block_rsv_check(struct btrfs_root *root,
4976                           struct btrfs_block_rsv *block_rsv, int min_factor)
4977 {
4978         u64 num_bytes = 0;
4979         int ret = -ENOSPC;
4980
4981         if (!block_rsv)
4982                 return 0;
4983
4984         spin_lock(&block_rsv->lock);
4985         num_bytes = div_factor(block_rsv->size, min_factor);
4986         if (block_rsv->reserved >= num_bytes)
4987                 ret = 0;
4988         spin_unlock(&block_rsv->lock);
4989
4990         return ret;
4991 }
4992
4993 int btrfs_block_rsv_refill(struct btrfs_root *root,
4994                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4995                            enum btrfs_reserve_flush_enum flush)
4996 {
4997         u64 num_bytes = 0;
4998         int ret = -ENOSPC;
4999
5000         if (!block_rsv)
5001                 return 0;
5002
5003         spin_lock(&block_rsv->lock);
5004         num_bytes = min_reserved;
5005         if (block_rsv->reserved >= num_bytes)
5006                 ret = 0;
5007         else
5008                 num_bytes -= block_rsv->reserved;
5009         spin_unlock(&block_rsv->lock);
5010
5011         if (!ret)
5012                 return 0;
5013
5014         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5015         if (!ret) {
5016                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5017                 return 0;
5018         }
5019
5020         return ret;
5021 }
5022
5023 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5024                             struct btrfs_block_rsv *dst_rsv,
5025                             u64 num_bytes)
5026 {
5027         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5028 }
5029
5030 void btrfs_block_rsv_release(struct btrfs_root *root,
5031                              struct btrfs_block_rsv *block_rsv,
5032                              u64 num_bytes)
5033 {
5034         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5035         if (global_rsv == block_rsv ||
5036             block_rsv->space_info != global_rsv->space_info)
5037                 global_rsv = NULL;
5038         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5039                                 num_bytes);
5040 }
5041
5042 /*
5043  * helper to calculate size of global block reservation.
5044  * the desired value is sum of space used by extent tree,
5045  * checksum tree and root tree
5046  */
5047 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5048 {
5049         struct btrfs_space_info *sinfo;
5050         u64 num_bytes;
5051         u64 meta_used;
5052         u64 data_used;
5053         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5054
5055         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5056         spin_lock(&sinfo->lock);
5057         data_used = sinfo->bytes_used;
5058         spin_unlock(&sinfo->lock);
5059
5060         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5061         spin_lock(&sinfo->lock);
5062         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5063                 data_used = 0;
5064         meta_used = sinfo->bytes_used;
5065         spin_unlock(&sinfo->lock);
5066
5067         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5068                     csum_size * 2;
5069         num_bytes += div_u64(data_used + meta_used, 50);
5070
5071         if (num_bytes * 3 > meta_used)
5072                 num_bytes = div_u64(meta_used, 3);
5073
5074         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5075 }
5076
5077 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5078 {
5079         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5080         struct btrfs_space_info *sinfo = block_rsv->space_info;
5081         u64 num_bytes;
5082
5083         num_bytes = calc_global_metadata_size(fs_info);
5084
5085         spin_lock(&sinfo->lock);
5086         spin_lock(&block_rsv->lock);
5087
5088         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
5089
5090         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5091                     sinfo->bytes_reserved + sinfo->bytes_readonly +
5092                     sinfo->bytes_may_use;
5093
5094         if (sinfo->total_bytes > num_bytes) {
5095                 num_bytes = sinfo->total_bytes - num_bytes;
5096                 block_rsv->reserved += num_bytes;
5097                 sinfo->bytes_may_use += num_bytes;
5098                 trace_btrfs_space_reservation(fs_info, "space_info",
5099                                       sinfo->flags, num_bytes, 1);
5100         }
5101
5102         if (block_rsv->reserved >= block_rsv->size) {
5103                 num_bytes = block_rsv->reserved - block_rsv->size;
5104                 sinfo->bytes_may_use -= num_bytes;
5105                 trace_btrfs_space_reservation(fs_info, "space_info",
5106                                       sinfo->flags, num_bytes, 0);
5107                 block_rsv->reserved = block_rsv->size;
5108                 block_rsv->full = 1;
5109         }
5110
5111         spin_unlock(&block_rsv->lock);
5112         spin_unlock(&sinfo->lock);
5113 }
5114
5115 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5116 {
5117         struct btrfs_space_info *space_info;
5118
5119         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5120         fs_info->chunk_block_rsv.space_info = space_info;
5121
5122         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5123         fs_info->global_block_rsv.space_info = space_info;
5124         fs_info->delalloc_block_rsv.space_info = space_info;
5125         fs_info->trans_block_rsv.space_info = space_info;
5126         fs_info->empty_block_rsv.space_info = space_info;
5127         fs_info->delayed_block_rsv.space_info = space_info;
5128
5129         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5130         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5131         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5132         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5133         if (fs_info->quota_root)
5134                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5135         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5136
5137         update_global_block_rsv(fs_info);
5138 }
5139
5140 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5141 {
5142         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5143                                 (u64)-1);
5144         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5145         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5146         WARN_ON(fs_info->trans_block_rsv.size > 0);
5147         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5148         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5149         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5150         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5151         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5152 }
5153
5154 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5155                                   struct btrfs_root *root)
5156 {
5157         if (!trans->block_rsv)
5158                 return;
5159
5160         if (!trans->bytes_reserved)
5161                 return;
5162
5163         trace_btrfs_space_reservation(root->fs_info, "transaction",
5164                                       trans->transid, trans->bytes_reserved, 0);
5165         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5166         trans->bytes_reserved = 0;
5167 }
5168
5169 /* Can only return 0 or -ENOSPC */
5170 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5171                                   struct inode *inode)
5172 {
5173         struct btrfs_root *root = BTRFS_I(inode)->root;
5174         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5175         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5176
5177         /*
5178          * We need to hold space in order to delete our orphan item once we've
5179          * added it, so this takes the reservation so we can release it later
5180          * when we are truly done with the orphan item.
5181          */
5182         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5183         trace_btrfs_space_reservation(root->fs_info, "orphan",
5184                                       btrfs_ino(inode), num_bytes, 1);
5185         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5186 }
5187
5188 void btrfs_orphan_release_metadata(struct inode *inode)
5189 {
5190         struct btrfs_root *root = BTRFS_I(inode)->root;
5191         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5192         trace_btrfs_space_reservation(root->fs_info, "orphan",
5193                                       btrfs_ino(inode), num_bytes, 0);
5194         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5195 }
5196
5197 /*
5198  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5199  * root: the root of the parent directory
5200  * rsv: block reservation
5201  * items: the number of items that we need do reservation
5202  * qgroup_reserved: used to return the reserved size in qgroup
5203  *
5204  * This function is used to reserve the space for snapshot/subvolume
5205  * creation and deletion. Those operations are different with the
5206  * common file/directory operations, they change two fs/file trees
5207  * and root tree, the number of items that the qgroup reserves is
5208  * different with the free space reservation. So we can not use
5209  * the space reseravtion mechanism in start_transaction().
5210  */
5211 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5212                                      struct btrfs_block_rsv *rsv,
5213                                      int items,
5214                                      u64 *qgroup_reserved,
5215                                      bool use_global_rsv)
5216 {
5217         u64 num_bytes;
5218         int ret;
5219         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5220
5221         if (root->fs_info->quota_enabled) {
5222                 /* One for parent inode, two for dir entries */
5223                 num_bytes = 3 * root->nodesize;
5224                 ret = btrfs_qgroup_reserve(root, num_bytes);
5225                 if (ret)
5226                         return ret;
5227         } else {
5228                 num_bytes = 0;
5229         }
5230
5231         *qgroup_reserved = num_bytes;
5232
5233         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5234         rsv->space_info = __find_space_info(root->fs_info,
5235                                             BTRFS_BLOCK_GROUP_METADATA);
5236         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5237                                   BTRFS_RESERVE_FLUSH_ALL);
5238
5239         if (ret == -ENOSPC && use_global_rsv)
5240                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5241
5242         if (ret) {
5243                 if (*qgroup_reserved)
5244                         btrfs_qgroup_free(root, *qgroup_reserved);
5245         }
5246
5247         return ret;
5248 }
5249
5250 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5251                                       struct btrfs_block_rsv *rsv,
5252                                       u64 qgroup_reserved)
5253 {
5254         btrfs_block_rsv_release(root, rsv, (u64)-1);
5255 }
5256
5257 /**
5258  * drop_outstanding_extent - drop an outstanding extent
5259  * @inode: the inode we're dropping the extent for
5260  * @num_bytes: the number of bytes we're relaseing.
5261  *
5262  * This is called when we are freeing up an outstanding extent, either called
5263  * after an error or after an extent is written.  This will return the number of
5264  * reserved extents that need to be freed.  This must be called with
5265  * BTRFS_I(inode)->lock held.
5266  */
5267 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5268 {
5269         unsigned drop_inode_space = 0;
5270         unsigned dropped_extents = 0;
5271         unsigned num_extents = 0;
5272
5273         num_extents = (unsigned)div64_u64(num_bytes +
5274                                           BTRFS_MAX_EXTENT_SIZE - 1,
5275                                           BTRFS_MAX_EXTENT_SIZE);
5276         ASSERT(num_extents);
5277         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5278         BTRFS_I(inode)->outstanding_extents -= num_extents;
5279
5280         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5281             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5282                                &BTRFS_I(inode)->runtime_flags))
5283                 drop_inode_space = 1;
5284
5285         /*
5286          * If we have more or the same amount of outsanding extents than we have
5287          * reserved then we need to leave the reserved extents count alone.
5288          */
5289         if (BTRFS_I(inode)->outstanding_extents >=
5290             BTRFS_I(inode)->reserved_extents)
5291                 return drop_inode_space;
5292
5293         dropped_extents = BTRFS_I(inode)->reserved_extents -
5294                 BTRFS_I(inode)->outstanding_extents;
5295         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5296         return dropped_extents + drop_inode_space;
5297 }
5298
5299 /**
5300  * calc_csum_metadata_size - return the amount of metada space that must be
5301  *      reserved/free'd for the given bytes.
5302  * @inode: the inode we're manipulating
5303  * @num_bytes: the number of bytes in question
5304  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5305  *
5306  * This adjusts the number of csum_bytes in the inode and then returns the
5307  * correct amount of metadata that must either be reserved or freed.  We
5308  * calculate how many checksums we can fit into one leaf and then divide the
5309  * number of bytes that will need to be checksumed by this value to figure out
5310  * how many checksums will be required.  If we are adding bytes then the number
5311  * may go up and we will return the number of additional bytes that must be
5312  * reserved.  If it is going down we will return the number of bytes that must
5313  * be freed.
5314  *
5315  * This must be called with BTRFS_I(inode)->lock held.
5316  */
5317 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5318                                    int reserve)
5319 {
5320         struct btrfs_root *root = BTRFS_I(inode)->root;
5321         u64 old_csums, num_csums;
5322
5323         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5324             BTRFS_I(inode)->csum_bytes == 0)
5325                 return 0;
5326
5327         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5328         if (reserve)
5329                 BTRFS_I(inode)->csum_bytes += num_bytes;
5330         else
5331                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5332         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5333
5334         /* No change, no need to reserve more */
5335         if (old_csums == num_csums)
5336                 return 0;
5337
5338         if (reserve)
5339                 return btrfs_calc_trans_metadata_size(root,
5340                                                       num_csums - old_csums);
5341
5342         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5343 }
5344
5345 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5346 {
5347         struct btrfs_root *root = BTRFS_I(inode)->root;
5348         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5349         u64 to_reserve = 0;
5350         u64 csum_bytes;
5351         unsigned nr_extents = 0;
5352         int extra_reserve = 0;
5353         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5354         int ret = 0;
5355         bool delalloc_lock = true;
5356         u64 to_free = 0;
5357         unsigned dropped;
5358
5359         /* If we are a free space inode we need to not flush since we will be in
5360          * the middle of a transaction commit.  We also don't need the delalloc
5361          * mutex since we won't race with anybody.  We need this mostly to make
5362          * lockdep shut its filthy mouth.
5363          */
5364         if (btrfs_is_free_space_inode(inode)) {
5365                 flush = BTRFS_RESERVE_NO_FLUSH;
5366                 delalloc_lock = false;
5367         }
5368
5369         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5370             btrfs_transaction_in_commit(root->fs_info))
5371                 schedule_timeout(1);
5372
5373         if (delalloc_lock)
5374                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5375
5376         num_bytes = ALIGN(num_bytes, root->sectorsize);
5377
5378         spin_lock(&BTRFS_I(inode)->lock);
5379         nr_extents = (unsigned)div64_u64(num_bytes +
5380                                          BTRFS_MAX_EXTENT_SIZE - 1,
5381                                          BTRFS_MAX_EXTENT_SIZE);
5382         BTRFS_I(inode)->outstanding_extents += nr_extents;
5383         nr_extents = 0;
5384
5385         if (BTRFS_I(inode)->outstanding_extents >
5386             BTRFS_I(inode)->reserved_extents)
5387                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5388                         BTRFS_I(inode)->reserved_extents;
5389
5390         /*
5391          * Add an item to reserve for updating the inode when we complete the
5392          * delalloc io.
5393          */
5394         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5395                       &BTRFS_I(inode)->runtime_flags)) {
5396                 nr_extents++;
5397                 extra_reserve = 1;
5398         }
5399
5400         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5401         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5402         csum_bytes = BTRFS_I(inode)->csum_bytes;
5403         spin_unlock(&BTRFS_I(inode)->lock);
5404
5405         if (root->fs_info->quota_enabled) {
5406                 ret = btrfs_qgroup_reserve(root, nr_extents * root->nodesize);
5407                 if (ret)
5408                         goto out_fail;
5409         }
5410
5411         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5412         if (unlikely(ret)) {
5413                 if (root->fs_info->quota_enabled)
5414                         btrfs_qgroup_free(root, nr_extents * root->nodesize);
5415                 goto out_fail;
5416         }
5417
5418         spin_lock(&BTRFS_I(inode)->lock);
5419         if (extra_reserve) {
5420                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5421                         &BTRFS_I(inode)->runtime_flags);
5422                 nr_extents--;
5423         }
5424         BTRFS_I(inode)->reserved_extents += nr_extents;
5425         spin_unlock(&BTRFS_I(inode)->lock);
5426
5427         if (delalloc_lock)
5428                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5429
5430         if (to_reserve)
5431                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5432                                               btrfs_ino(inode), to_reserve, 1);
5433         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5434
5435         return 0;
5436
5437 out_fail:
5438         spin_lock(&BTRFS_I(inode)->lock);
5439         dropped = drop_outstanding_extent(inode, num_bytes);
5440         /*
5441          * If the inodes csum_bytes is the same as the original
5442          * csum_bytes then we know we haven't raced with any free()ers
5443          * so we can just reduce our inodes csum bytes and carry on.
5444          */
5445         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5446                 calc_csum_metadata_size(inode, num_bytes, 0);
5447         } else {
5448                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5449                 u64 bytes;
5450
5451                 /*
5452                  * This is tricky, but first we need to figure out how much we
5453                  * free'd from any free-ers that occured during this
5454                  * reservation, so we reset ->csum_bytes to the csum_bytes
5455                  * before we dropped our lock, and then call the free for the
5456                  * number of bytes that were freed while we were trying our
5457                  * reservation.
5458                  */
5459                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5460                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5461                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5462
5463
5464                 /*
5465                  * Now we need to see how much we would have freed had we not
5466                  * been making this reservation and our ->csum_bytes were not
5467                  * artificially inflated.
5468                  */
5469                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5470                 bytes = csum_bytes - orig_csum_bytes;
5471                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5472
5473                 /*
5474                  * Now reset ->csum_bytes to what it should be.  If bytes is
5475                  * more than to_free then we would have free'd more space had we
5476                  * not had an artificially high ->csum_bytes, so we need to free
5477                  * the remainder.  If bytes is the same or less then we don't
5478                  * need to do anything, the other free-ers did the correct
5479                  * thing.
5480                  */
5481                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5482                 if (bytes > to_free)
5483                         to_free = bytes - to_free;
5484                 else
5485                         to_free = 0;
5486         }
5487         spin_unlock(&BTRFS_I(inode)->lock);
5488         if (dropped)
5489                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5490
5491         if (to_free) {
5492                 btrfs_block_rsv_release(root, block_rsv, to_free);
5493                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5494                                               btrfs_ino(inode), to_free, 0);
5495         }
5496         if (delalloc_lock)
5497                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5498         return ret;
5499 }
5500
5501 /**
5502  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5503  * @inode: the inode to release the reservation for
5504  * @num_bytes: the number of bytes we're releasing
5505  *
5506  * This will release the metadata reservation for an inode.  This can be called
5507  * once we complete IO for a given set of bytes to release their metadata
5508  * reservations.
5509  */
5510 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5511 {
5512         struct btrfs_root *root = BTRFS_I(inode)->root;
5513         u64 to_free = 0;
5514         unsigned dropped;
5515
5516         num_bytes = ALIGN(num_bytes, root->sectorsize);
5517         spin_lock(&BTRFS_I(inode)->lock);
5518         dropped = drop_outstanding_extent(inode, num_bytes);
5519
5520         if (num_bytes)
5521                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5522         spin_unlock(&BTRFS_I(inode)->lock);
5523         if (dropped > 0)
5524                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5525
5526         if (btrfs_test_is_dummy_root(root))
5527                 return;
5528
5529         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5530                                       btrfs_ino(inode), to_free, 0);
5531
5532         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5533                                 to_free);
5534 }
5535
5536 /**
5537  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5538  * @inode: inode we're writing to
5539  * @num_bytes: the number of bytes we want to allocate
5540  *
5541  * This will do the following things
5542  *
5543  * o reserve space in the data space info for num_bytes
5544  * o reserve space in the metadata space info based on number of outstanding
5545  *   extents and how much csums will be needed
5546  * o add to the inodes ->delalloc_bytes
5547  * o add it to the fs_info's delalloc inodes list.
5548  *
5549  * This will return 0 for success and -ENOSPC if there is no space left.
5550  */
5551 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5552 {
5553         int ret;
5554
5555         ret = btrfs_check_data_free_space(inode, num_bytes, num_bytes);
5556         if (ret)
5557                 return ret;
5558
5559         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5560         if (ret) {
5561                 btrfs_free_reserved_data_space(inode, num_bytes);
5562                 return ret;
5563         }
5564
5565         return 0;
5566 }
5567
5568 /**
5569  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5570  * @inode: inode we're releasing space for
5571  * @num_bytes: the number of bytes we want to free up
5572  *
5573  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5574  * called in the case that we don't need the metadata AND data reservations
5575  * anymore.  So if there is an error or we insert an inline extent.
5576  *
5577  * This function will release the metadata space that was not used and will
5578  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5579  * list if there are no delalloc bytes left.
5580  */
5581 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5582 {
5583         btrfs_delalloc_release_metadata(inode, num_bytes);
5584         btrfs_free_reserved_data_space(inode, num_bytes);
5585 }
5586
5587 static int update_block_group(struct btrfs_trans_handle *trans,
5588                               struct btrfs_root *root, u64 bytenr,
5589                               u64 num_bytes, int alloc)
5590 {
5591         struct btrfs_block_group_cache *cache = NULL;
5592         struct btrfs_fs_info *info = root->fs_info;
5593         u64 total = num_bytes;
5594         u64 old_val;
5595         u64 byte_in_group;
5596         int factor;
5597
5598         /* block accounting for super block */
5599         spin_lock(&info->delalloc_root_lock);
5600         old_val = btrfs_super_bytes_used(info->super_copy);
5601         if (alloc)
5602                 old_val += num_bytes;
5603         else
5604                 old_val -= num_bytes;
5605         btrfs_set_super_bytes_used(info->super_copy, old_val);
5606         spin_unlock(&info->delalloc_root_lock);
5607
5608         while (total) {
5609                 cache = btrfs_lookup_block_group(info, bytenr);
5610                 if (!cache)
5611                         return -ENOENT;
5612                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5613                                     BTRFS_BLOCK_GROUP_RAID1 |
5614                                     BTRFS_BLOCK_GROUP_RAID10))
5615                         factor = 2;
5616                 else
5617                         factor = 1;
5618                 /*
5619                  * If this block group has free space cache written out, we
5620                  * need to make sure to load it if we are removing space.  This
5621                  * is because we need the unpinning stage to actually add the
5622                  * space back to the block group, otherwise we will leak space.
5623                  */
5624                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5625                         cache_block_group(cache, 1);
5626
5627                 byte_in_group = bytenr - cache->key.objectid;
5628                 WARN_ON(byte_in_group > cache->key.offset);
5629
5630                 spin_lock(&cache->space_info->lock);
5631                 spin_lock(&cache->lock);
5632
5633                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5634                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5635                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5636
5637                 old_val = btrfs_block_group_used(&cache->item);
5638                 num_bytes = min(total, cache->key.offset - byte_in_group);
5639                 if (alloc) {
5640                         old_val += num_bytes;
5641                         btrfs_set_block_group_used(&cache->item, old_val);
5642                         cache->reserved -= num_bytes;
5643                         cache->space_info->bytes_reserved -= num_bytes;
5644                         cache->space_info->bytes_used += num_bytes;
5645                         cache->space_info->disk_used += num_bytes * factor;
5646                         spin_unlock(&cache->lock);
5647                         spin_unlock(&cache->space_info->lock);
5648                 } else {
5649                         old_val -= num_bytes;
5650                         btrfs_set_block_group_used(&cache->item, old_val);
5651                         cache->pinned += num_bytes;
5652                         cache->space_info->bytes_pinned += num_bytes;
5653                         cache->space_info->bytes_used -= num_bytes;
5654                         cache->space_info->disk_used -= num_bytes * factor;
5655                         spin_unlock(&cache->lock);
5656                         spin_unlock(&cache->space_info->lock);
5657
5658                         set_extent_dirty(info->pinned_extents,
5659                                          bytenr, bytenr + num_bytes - 1,
5660                                          GFP_NOFS | __GFP_NOFAIL);
5661                         /*
5662                          * No longer have used bytes in this block group, queue
5663                          * it for deletion.
5664                          */
5665                         if (old_val == 0) {
5666                                 spin_lock(&info->unused_bgs_lock);
5667                                 if (list_empty(&cache->bg_list)) {
5668                                         btrfs_get_block_group(cache);
5669                                         list_add_tail(&cache->bg_list,
5670                                                       &info->unused_bgs);
5671                                 }
5672                                 spin_unlock(&info->unused_bgs_lock);
5673                         }
5674                 }
5675
5676                 spin_lock(&trans->transaction->dirty_bgs_lock);
5677                 if (list_empty(&cache->dirty_list)) {
5678                         list_add_tail(&cache->dirty_list,
5679                                       &trans->transaction->dirty_bgs);
5680                                 trans->transaction->num_dirty_bgs++;
5681                         btrfs_get_block_group(cache);
5682                 }
5683                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5684
5685                 btrfs_put_block_group(cache);
5686                 total -= num_bytes;
5687                 bytenr += num_bytes;
5688         }
5689         return 0;
5690 }
5691
5692 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5693 {
5694         struct btrfs_block_group_cache *cache;
5695         u64 bytenr;
5696
5697         spin_lock(&root->fs_info->block_group_cache_lock);
5698         bytenr = root->fs_info->first_logical_byte;
5699         spin_unlock(&root->fs_info->block_group_cache_lock);
5700
5701         if (bytenr < (u64)-1)
5702                 return bytenr;
5703
5704         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5705         if (!cache)
5706                 return 0;
5707
5708         bytenr = cache->key.objectid;
5709         btrfs_put_block_group(cache);
5710
5711         return bytenr;
5712 }
5713
5714 static int pin_down_extent(struct btrfs_root *root,
5715                            struct btrfs_block_group_cache *cache,
5716                            u64 bytenr, u64 num_bytes, int reserved)
5717 {
5718         spin_lock(&cache->space_info->lock);
5719         spin_lock(&cache->lock);
5720         cache->pinned += num_bytes;
5721         cache->space_info->bytes_pinned += num_bytes;
5722         if (reserved) {
5723                 cache->reserved -= num_bytes;
5724                 cache->space_info->bytes_reserved -= num_bytes;
5725         }
5726         spin_unlock(&cache->lock);
5727         spin_unlock(&cache->space_info->lock);
5728
5729         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5730                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5731         if (reserved)
5732                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5733         return 0;
5734 }
5735
5736 /*
5737  * this function must be called within transaction
5738  */
5739 int btrfs_pin_extent(struct btrfs_root *root,
5740                      u64 bytenr, u64 num_bytes, int reserved)
5741 {
5742         struct btrfs_block_group_cache *cache;
5743
5744         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5745         BUG_ON(!cache); /* Logic error */
5746
5747         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5748
5749         btrfs_put_block_group(cache);
5750         return 0;
5751 }
5752
5753 /*
5754  * this function must be called within transaction
5755  */
5756 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5757                                     u64 bytenr, u64 num_bytes)
5758 {
5759         struct btrfs_block_group_cache *cache;
5760         int ret;
5761
5762         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5763         if (!cache)
5764                 return -EINVAL;
5765
5766         /*
5767          * pull in the free space cache (if any) so that our pin
5768          * removes the free space from the cache.  We have load_only set
5769          * to one because the slow code to read in the free extents does check
5770          * the pinned extents.
5771          */
5772         cache_block_group(cache, 1);
5773
5774         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5775
5776         /* remove us from the free space cache (if we're there at all) */
5777         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5778         btrfs_put_block_group(cache);
5779         return ret;
5780 }
5781
5782 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5783 {
5784         int ret;
5785         struct btrfs_block_group_cache *block_group;
5786         struct btrfs_caching_control *caching_ctl;
5787
5788         block_group = btrfs_lookup_block_group(root->fs_info, start);
5789         if (!block_group)
5790                 return -EINVAL;
5791
5792         cache_block_group(block_group, 0);
5793         caching_ctl = get_caching_control(block_group);
5794
5795         if (!caching_ctl) {
5796                 /* Logic error */
5797                 BUG_ON(!block_group_cache_done(block_group));
5798                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5799         } else {
5800                 mutex_lock(&caching_ctl->mutex);
5801
5802                 if (start >= caching_ctl->progress) {
5803                         ret = add_excluded_extent(root, start, num_bytes);
5804                 } else if (start + num_bytes <= caching_ctl->progress) {
5805                         ret = btrfs_remove_free_space(block_group,
5806                                                       start, num_bytes);
5807                 } else {
5808                         num_bytes = caching_ctl->progress - start;
5809                         ret = btrfs_remove_free_space(block_group,
5810                                                       start, num_bytes);
5811                         if (ret)
5812                                 goto out_lock;
5813
5814                         num_bytes = (start + num_bytes) -
5815                                 caching_ctl->progress;
5816                         start = caching_ctl->progress;
5817                         ret = add_excluded_extent(root, start, num_bytes);
5818                 }
5819 out_lock:
5820                 mutex_unlock(&caching_ctl->mutex);
5821                 put_caching_control(caching_ctl);
5822         }
5823         btrfs_put_block_group(block_group);
5824         return ret;
5825 }
5826
5827 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5828                                  struct extent_buffer *eb)
5829 {
5830         struct btrfs_file_extent_item *item;
5831         struct btrfs_key key;
5832         int found_type;
5833         int i;
5834
5835         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5836                 return 0;
5837
5838         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5839                 btrfs_item_key_to_cpu(eb, &key, i);
5840                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5841                         continue;
5842                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5843                 found_type = btrfs_file_extent_type(eb, item);
5844                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5845                         continue;
5846                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5847                         continue;
5848                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5849                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5850                 __exclude_logged_extent(log, key.objectid, key.offset);
5851         }
5852
5853         return 0;
5854 }
5855
5856 /**
5857  * btrfs_update_reserved_bytes - update the block_group and space info counters
5858  * @cache:      The cache we are manipulating
5859  * @num_bytes:  The number of bytes in question
5860  * @reserve:    One of the reservation enums
5861  * @delalloc:   The blocks are allocated for the delalloc write
5862  *
5863  * This is called by the allocator when it reserves space, or by somebody who is
5864  * freeing space that was never actually used on disk.  For example if you
5865  * reserve some space for a new leaf in transaction A and before transaction A
5866  * commits you free that leaf, you call this with reserve set to 0 in order to
5867  * clear the reservation.
5868  *
5869  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5870  * ENOSPC accounting.  For data we handle the reservation through clearing the
5871  * delalloc bits in the io_tree.  We have to do this since we could end up
5872  * allocating less disk space for the amount of data we have reserved in the
5873  * case of compression.
5874  *
5875  * If this is a reservation and the block group has become read only we cannot
5876  * make the reservation and return -EAGAIN, otherwise this function always
5877  * succeeds.
5878  */
5879 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5880                                        u64 num_bytes, int reserve, int delalloc)
5881 {
5882         struct btrfs_space_info *space_info = cache->space_info;
5883         int ret = 0;
5884
5885         spin_lock(&space_info->lock);
5886         spin_lock(&cache->lock);
5887         if (reserve != RESERVE_FREE) {
5888                 if (cache->ro) {
5889                         ret = -EAGAIN;
5890                 } else {
5891                         cache->reserved += num_bytes;
5892                         space_info->bytes_reserved += num_bytes;
5893                         if (reserve == RESERVE_ALLOC) {
5894                                 trace_btrfs_space_reservation(cache->fs_info,
5895                                                 "space_info", space_info->flags,
5896                                                 num_bytes, 0);
5897                                 space_info->bytes_may_use -= num_bytes;
5898                         }
5899
5900                         if (delalloc)
5901                                 cache->delalloc_bytes += num_bytes;
5902                 }
5903         } else {
5904                 if (cache->ro)
5905                         space_info->bytes_readonly += num_bytes;
5906                 cache->reserved -= num_bytes;
5907                 space_info->bytes_reserved -= num_bytes;
5908
5909                 if (delalloc)
5910                         cache->delalloc_bytes -= num_bytes;
5911         }
5912         spin_unlock(&cache->lock);
5913         spin_unlock(&space_info->lock);
5914         return ret;
5915 }
5916
5917 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5918                                 struct btrfs_root *root)
5919 {
5920         struct btrfs_fs_info *fs_info = root->fs_info;
5921         struct btrfs_caching_control *next;
5922         struct btrfs_caching_control *caching_ctl;
5923         struct btrfs_block_group_cache *cache;
5924
5925         down_write(&fs_info->commit_root_sem);
5926
5927         list_for_each_entry_safe(caching_ctl, next,
5928                                  &fs_info->caching_block_groups, list) {
5929                 cache = caching_ctl->block_group;
5930                 if (block_group_cache_done(cache)) {
5931                         cache->last_byte_to_unpin = (u64)-1;
5932                         list_del_init(&caching_ctl->list);
5933                         put_caching_control(caching_ctl);
5934                 } else {
5935                         cache->last_byte_to_unpin = caching_ctl->progress;
5936                 }
5937         }
5938
5939         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5940                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5941         else
5942                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5943
5944         up_write(&fs_info->commit_root_sem);
5945
5946         update_global_block_rsv(fs_info);
5947 }
5948
5949 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
5950                               const bool return_free_space)
5951 {
5952         struct btrfs_fs_info *fs_info = root->fs_info;
5953         struct btrfs_block_group_cache *cache = NULL;
5954         struct btrfs_space_info *space_info;
5955         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5956         u64 len;
5957         bool readonly;
5958
5959         while (start <= end) {
5960                 readonly = false;
5961                 if (!cache ||
5962                     start >= cache->key.objectid + cache->key.offset) {
5963                         if (cache)
5964                                 btrfs_put_block_group(cache);
5965                         cache = btrfs_lookup_block_group(fs_info, start);
5966                         BUG_ON(!cache); /* Logic error */
5967                 }
5968
5969                 len = cache->key.objectid + cache->key.offset - start;
5970                 len = min(len, end + 1 - start);
5971
5972                 if (start < cache->last_byte_to_unpin) {
5973                         len = min(len, cache->last_byte_to_unpin - start);
5974                         if (return_free_space)
5975                                 btrfs_add_free_space(cache, start, len);
5976                 }
5977
5978                 start += len;
5979                 space_info = cache->space_info;
5980
5981                 spin_lock(&space_info->lock);
5982                 spin_lock(&cache->lock);
5983                 cache->pinned -= len;
5984                 space_info->bytes_pinned -= len;
5985                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
5986                 if (cache->ro) {
5987                         space_info->bytes_readonly += len;
5988                         readonly = true;
5989                 }
5990                 spin_unlock(&cache->lock);
5991                 if (!readonly && global_rsv->space_info == space_info) {
5992                         spin_lock(&global_rsv->lock);
5993                         if (!global_rsv->full) {
5994                                 len = min(len, global_rsv->size -
5995                                           global_rsv->reserved);
5996                                 global_rsv->reserved += len;
5997                                 space_info->bytes_may_use += len;
5998                                 if (global_rsv->reserved >= global_rsv->size)
5999                                         global_rsv->full = 1;
6000                         }
6001                         spin_unlock(&global_rsv->lock);
6002                 }
6003                 spin_unlock(&space_info->lock);
6004         }
6005
6006         if (cache)
6007                 btrfs_put_block_group(cache);
6008         return 0;
6009 }
6010
6011 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6012                                struct btrfs_root *root)
6013 {
6014         struct btrfs_fs_info *fs_info = root->fs_info;
6015         struct extent_io_tree *unpin;
6016         u64 start;
6017         u64 end;
6018         int ret;
6019
6020         if (trans->aborted)
6021                 return 0;
6022
6023         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6024                 unpin = &fs_info->freed_extents[1];
6025         else
6026                 unpin = &fs_info->freed_extents[0];
6027
6028         while (1) {
6029                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6030                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6031                                             EXTENT_DIRTY, NULL);
6032                 if (ret) {
6033                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6034                         break;
6035                 }
6036
6037                 if (btrfs_test_opt(root, DISCARD))
6038                         ret = btrfs_discard_extent(root, start,
6039                                                    end + 1 - start, NULL);
6040
6041                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6042                 unpin_extent_range(root, start, end, true);
6043                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6044                 cond_resched();
6045         }
6046
6047         return 0;
6048 }
6049
6050 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6051                              u64 owner, u64 root_objectid)
6052 {
6053         struct btrfs_space_info *space_info;
6054         u64 flags;
6055
6056         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6057                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6058                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6059                 else
6060                         flags = BTRFS_BLOCK_GROUP_METADATA;
6061         } else {
6062                 flags = BTRFS_BLOCK_GROUP_DATA;
6063         }
6064
6065         space_info = __find_space_info(fs_info, flags);
6066         BUG_ON(!space_info); /* Logic bug */
6067         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6068 }
6069
6070
6071 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6072                                 struct btrfs_root *root,
6073                                 u64 bytenr, u64 num_bytes, u64 parent,
6074                                 u64 root_objectid, u64 owner_objectid,
6075                                 u64 owner_offset, int refs_to_drop,
6076                                 struct btrfs_delayed_extent_op *extent_op,
6077                                 int no_quota)
6078 {
6079         struct btrfs_key key;
6080         struct btrfs_path *path;
6081         struct btrfs_fs_info *info = root->fs_info;
6082         struct btrfs_root *extent_root = info->extent_root;
6083         struct extent_buffer *leaf;
6084         struct btrfs_extent_item *ei;
6085         struct btrfs_extent_inline_ref *iref;
6086         int ret;
6087         int is_data;
6088         int extent_slot = 0;
6089         int found_extent = 0;
6090         int num_to_del = 1;
6091         u32 item_size;
6092         u64 refs;
6093         int last_ref = 0;
6094         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_SUB_EXCL;
6095         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6096                                                  SKINNY_METADATA);
6097
6098         if (!info->quota_enabled || !is_fstree(root_objectid))
6099                 no_quota = 1;
6100
6101         path = btrfs_alloc_path();
6102         if (!path)
6103                 return -ENOMEM;
6104
6105         path->reada = 1;
6106         path->leave_spinning = 1;
6107
6108         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6109         BUG_ON(!is_data && refs_to_drop != 1);
6110
6111         if (is_data)
6112                 skinny_metadata = 0;
6113
6114         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6115                                     bytenr, num_bytes, parent,
6116                                     root_objectid, owner_objectid,
6117                                     owner_offset);
6118         if (ret == 0) {
6119                 extent_slot = path->slots[0];
6120                 while (extent_slot >= 0) {
6121                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6122                                               extent_slot);
6123                         if (key.objectid != bytenr)
6124                                 break;
6125                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6126                             key.offset == num_bytes) {
6127                                 found_extent = 1;
6128                                 break;
6129                         }
6130                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6131                             key.offset == owner_objectid) {
6132                                 found_extent = 1;
6133                                 break;
6134                         }
6135                         if (path->slots[0] - extent_slot > 5)
6136                                 break;
6137                         extent_slot--;
6138                 }
6139 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6140                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6141                 if (found_extent && item_size < sizeof(*ei))
6142                         found_extent = 0;
6143 #endif
6144                 if (!found_extent) {
6145                         BUG_ON(iref);
6146                         ret = remove_extent_backref(trans, extent_root, path,
6147                                                     NULL, refs_to_drop,
6148                                                     is_data, &last_ref);
6149                         if (ret) {
6150                                 btrfs_abort_transaction(trans, extent_root, ret);
6151                                 goto out;
6152                         }
6153                         btrfs_release_path(path);
6154                         path->leave_spinning = 1;
6155
6156                         key.objectid = bytenr;
6157                         key.type = BTRFS_EXTENT_ITEM_KEY;
6158                         key.offset = num_bytes;
6159
6160                         if (!is_data && skinny_metadata) {
6161                                 key.type = BTRFS_METADATA_ITEM_KEY;
6162                                 key.offset = owner_objectid;
6163                         }
6164
6165                         ret = btrfs_search_slot(trans, extent_root,
6166                                                 &key, path, -1, 1);
6167                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6168                                 /*
6169                                  * Couldn't find our skinny metadata item,
6170                                  * see if we have ye olde extent item.
6171                                  */
6172                                 path->slots[0]--;
6173                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6174                                                       path->slots[0]);
6175                                 if (key.objectid == bytenr &&
6176                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6177                                     key.offset == num_bytes)
6178                                         ret = 0;
6179                         }
6180
6181                         if (ret > 0 && skinny_metadata) {
6182                                 skinny_metadata = false;
6183                                 key.objectid = bytenr;
6184                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6185                                 key.offset = num_bytes;
6186                                 btrfs_release_path(path);
6187                                 ret = btrfs_search_slot(trans, extent_root,
6188                                                         &key, path, -1, 1);
6189                         }
6190
6191                         if (ret) {
6192                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6193                                         ret, bytenr);
6194                                 if (ret > 0)
6195                                         btrfs_print_leaf(extent_root,
6196                                                          path->nodes[0]);
6197                         }
6198                         if (ret < 0) {
6199                                 btrfs_abort_transaction(trans, extent_root, ret);
6200                                 goto out;
6201                         }
6202                         extent_slot = path->slots[0];
6203                 }
6204         } else if (WARN_ON(ret == -ENOENT)) {
6205                 btrfs_print_leaf(extent_root, path->nodes[0]);
6206                 btrfs_err(info,
6207                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6208                         bytenr, parent, root_objectid, owner_objectid,
6209                         owner_offset);
6210                 btrfs_abort_transaction(trans, extent_root, ret);
6211                 goto out;
6212         } else {
6213                 btrfs_abort_transaction(trans, extent_root, ret);
6214                 goto out;
6215         }
6216
6217         leaf = path->nodes[0];
6218         item_size = btrfs_item_size_nr(leaf, extent_slot);
6219 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6220         if (item_size < sizeof(*ei)) {
6221                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6222                 ret = convert_extent_item_v0(trans, extent_root, path,
6223                                              owner_objectid, 0);
6224                 if (ret < 0) {
6225                         btrfs_abort_transaction(trans, extent_root, ret);
6226                         goto out;
6227                 }
6228
6229                 btrfs_release_path(path);
6230                 path->leave_spinning = 1;
6231
6232                 key.objectid = bytenr;
6233                 key.type = BTRFS_EXTENT_ITEM_KEY;
6234                 key.offset = num_bytes;
6235
6236                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6237                                         -1, 1);
6238                 if (ret) {
6239                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6240                                 ret, bytenr);
6241                         btrfs_print_leaf(extent_root, path->nodes[0]);
6242                 }
6243                 if (ret < 0) {
6244                         btrfs_abort_transaction(trans, extent_root, ret);
6245                         goto out;
6246                 }
6247
6248                 extent_slot = path->slots[0];
6249                 leaf = path->nodes[0];
6250                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6251         }
6252 #endif
6253         BUG_ON(item_size < sizeof(*ei));
6254         ei = btrfs_item_ptr(leaf, extent_slot,
6255                             struct btrfs_extent_item);
6256         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6257             key.type == BTRFS_EXTENT_ITEM_KEY) {
6258                 struct btrfs_tree_block_info *bi;
6259                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6260                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6261                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6262         }
6263
6264         refs = btrfs_extent_refs(leaf, ei);
6265         if (refs < refs_to_drop) {
6266                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6267                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6268                 ret = -EINVAL;
6269                 btrfs_abort_transaction(trans, extent_root, ret);
6270                 goto out;
6271         }
6272         refs -= refs_to_drop;
6273
6274         if (refs > 0) {
6275                 type = BTRFS_QGROUP_OPER_SUB_SHARED;
6276                 if (extent_op)
6277                         __run_delayed_extent_op(extent_op, leaf, ei);
6278                 /*
6279                  * In the case of inline back ref, reference count will
6280                  * be updated by remove_extent_backref
6281                  */
6282                 if (iref) {
6283                         BUG_ON(!found_extent);
6284                 } else {
6285                         btrfs_set_extent_refs(leaf, ei, refs);
6286                         btrfs_mark_buffer_dirty(leaf);
6287                 }
6288                 if (found_extent) {
6289                         ret = remove_extent_backref(trans, extent_root, path,
6290                                                     iref, refs_to_drop,
6291                                                     is_data, &last_ref);
6292                         if (ret) {
6293                                 btrfs_abort_transaction(trans, extent_root, ret);
6294                                 goto out;
6295                         }
6296                 }
6297                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6298                                  root_objectid);
6299         } else {
6300                 if (found_extent) {
6301                         BUG_ON(is_data && refs_to_drop !=
6302                                extent_data_ref_count(root, path, iref));
6303                         if (iref) {
6304                                 BUG_ON(path->slots[0] != extent_slot);
6305                         } else {
6306                                 BUG_ON(path->slots[0] != extent_slot + 1);
6307                                 path->slots[0] = extent_slot;
6308                                 num_to_del = 2;
6309                         }
6310                 }
6311
6312                 last_ref = 1;
6313                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6314                                       num_to_del);
6315                 if (ret) {
6316                         btrfs_abort_transaction(trans, extent_root, ret);
6317                         goto out;
6318                 }
6319                 btrfs_release_path(path);
6320
6321                 if (is_data) {
6322                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6323                         if (ret) {
6324                                 btrfs_abort_transaction(trans, extent_root, ret);
6325                                 goto out;
6326                         }
6327                 }
6328
6329                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6330                 if (ret) {
6331                         btrfs_abort_transaction(trans, extent_root, ret);
6332                         goto out;
6333                 }
6334         }
6335         btrfs_release_path(path);
6336
6337         /* Deal with the quota accounting */
6338         if (!ret && last_ref && !no_quota) {
6339                 int mod_seq = 0;
6340
6341                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
6342                     type == BTRFS_QGROUP_OPER_SUB_SHARED)
6343                         mod_seq = 1;
6344
6345                 ret = btrfs_qgroup_record_ref(trans, info, root_objectid,
6346                                               bytenr, num_bytes, type,
6347                                               mod_seq);
6348         }
6349 out:
6350         btrfs_free_path(path);
6351         return ret;
6352 }
6353
6354 /*
6355  * when we free an block, it is possible (and likely) that we free the last
6356  * delayed ref for that extent as well.  This searches the delayed ref tree for
6357  * a given extent, and if there are no other delayed refs to be processed, it
6358  * removes it from the tree.
6359  */
6360 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6361                                       struct btrfs_root *root, u64 bytenr)
6362 {
6363         struct btrfs_delayed_ref_head *head;
6364         struct btrfs_delayed_ref_root *delayed_refs;
6365         int ret = 0;
6366
6367         delayed_refs = &trans->transaction->delayed_refs;
6368         spin_lock(&delayed_refs->lock);
6369         head = btrfs_find_delayed_ref_head(trans, bytenr);
6370         if (!head)
6371                 goto out_delayed_unlock;
6372
6373         spin_lock(&head->lock);
6374         if (rb_first(&head->ref_root))
6375                 goto out;
6376
6377         if (head->extent_op) {
6378                 if (!head->must_insert_reserved)
6379                         goto out;
6380                 btrfs_free_delayed_extent_op(head->extent_op);
6381                 head->extent_op = NULL;
6382         }
6383
6384         /*
6385          * waiting for the lock here would deadlock.  If someone else has it
6386          * locked they are already in the process of dropping it anyway
6387          */
6388         if (!mutex_trylock(&head->mutex))
6389                 goto out;
6390
6391         /*
6392          * at this point we have a head with no other entries.  Go
6393          * ahead and process it.
6394          */
6395         head->node.in_tree = 0;
6396         rb_erase(&head->href_node, &delayed_refs->href_root);
6397
6398         atomic_dec(&delayed_refs->num_entries);
6399
6400         /*
6401          * we don't take a ref on the node because we're removing it from the
6402          * tree, so we just steal the ref the tree was holding.
6403          */
6404         delayed_refs->num_heads--;
6405         if (head->processing == 0)
6406                 delayed_refs->num_heads_ready--;
6407         head->processing = 0;
6408         spin_unlock(&head->lock);
6409         spin_unlock(&delayed_refs->lock);
6410
6411         BUG_ON(head->extent_op);
6412         if (head->must_insert_reserved)
6413                 ret = 1;
6414
6415         mutex_unlock(&head->mutex);
6416         btrfs_put_delayed_ref(&head->node);
6417         return ret;
6418 out:
6419         spin_unlock(&head->lock);
6420
6421 out_delayed_unlock:
6422         spin_unlock(&delayed_refs->lock);
6423         return 0;
6424 }
6425
6426 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6427                            struct btrfs_root *root,
6428                            struct extent_buffer *buf,
6429                            u64 parent, int last_ref)
6430 {
6431         int pin = 1;
6432         int ret;
6433
6434         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6435                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6436                                         buf->start, buf->len,
6437                                         parent, root->root_key.objectid,
6438                                         btrfs_header_level(buf),
6439                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6440                 BUG_ON(ret); /* -ENOMEM */
6441         }
6442
6443         if (!last_ref)
6444                 return;
6445
6446         if (btrfs_header_generation(buf) == trans->transid) {
6447                 struct btrfs_block_group_cache *cache;
6448
6449                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6450                         ret = check_ref_cleanup(trans, root, buf->start);
6451                         if (!ret)
6452                                 goto out;
6453                 }
6454
6455                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6456
6457                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6458                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6459                         btrfs_put_block_group(cache);
6460                         goto out;
6461                 }
6462
6463                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6464
6465                 btrfs_add_free_space(cache, buf->start, buf->len);
6466                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6467                 btrfs_put_block_group(cache);
6468                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6469                 pin = 0;
6470         }
6471 out:
6472         if (pin)
6473                 add_pinned_bytes(root->fs_info, buf->len,
6474                                  btrfs_header_level(buf),
6475                                  root->root_key.objectid);
6476
6477         /*
6478          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6479          * anymore.
6480          */
6481         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6482 }
6483
6484 /* Can return -ENOMEM */
6485 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6486                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6487                       u64 owner, u64 offset, int no_quota)
6488 {
6489         int ret;
6490         struct btrfs_fs_info *fs_info = root->fs_info;
6491
6492         if (btrfs_test_is_dummy_root(root))
6493                 return 0;
6494
6495         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6496
6497         /*
6498          * tree log blocks never actually go into the extent allocation
6499          * tree, just update pinning info and exit early.
6500          */
6501         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6502                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6503                 /* unlocks the pinned mutex */
6504                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6505                 ret = 0;
6506         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6507                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6508                                         num_bytes,
6509                                         parent, root_objectid, (int)owner,
6510                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6511         } else {
6512                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6513                                                 num_bytes,
6514                                                 parent, root_objectid, owner,
6515                                                 offset, BTRFS_DROP_DELAYED_REF,
6516                                                 NULL, no_quota);
6517         }
6518         return ret;
6519 }
6520
6521 /*
6522  * when we wait for progress in the block group caching, its because
6523  * our allocation attempt failed at least once.  So, we must sleep
6524  * and let some progress happen before we try again.
6525  *
6526  * This function will sleep at least once waiting for new free space to
6527  * show up, and then it will check the block group free space numbers
6528  * for our min num_bytes.  Another option is to have it go ahead
6529  * and look in the rbtree for a free extent of a given size, but this
6530  * is a good start.
6531  *
6532  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6533  * any of the information in this block group.
6534  */
6535 static noinline void
6536 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6537                                 u64 num_bytes)
6538 {
6539         struct btrfs_caching_control *caching_ctl;
6540
6541         caching_ctl = get_caching_control(cache);
6542         if (!caching_ctl)
6543                 return;
6544
6545         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6546                    (cache->free_space_ctl->free_space >= num_bytes));
6547
6548         put_caching_control(caching_ctl);
6549 }
6550
6551 static noinline int
6552 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6553 {
6554         struct btrfs_caching_control *caching_ctl;
6555         int ret = 0;
6556
6557         caching_ctl = get_caching_control(cache);
6558         if (!caching_ctl)
6559                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6560
6561         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6562         if (cache->cached == BTRFS_CACHE_ERROR)
6563                 ret = -EIO;
6564         put_caching_control(caching_ctl);
6565         return ret;
6566 }
6567
6568 int __get_raid_index(u64 flags)
6569 {
6570         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6571                 return BTRFS_RAID_RAID10;
6572         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6573                 return BTRFS_RAID_RAID1;
6574         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6575                 return BTRFS_RAID_DUP;
6576         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6577                 return BTRFS_RAID_RAID0;
6578         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6579                 return BTRFS_RAID_RAID5;
6580         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6581                 return BTRFS_RAID_RAID6;
6582
6583         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6584 }
6585
6586 int get_block_group_index(struct btrfs_block_group_cache *cache)
6587 {
6588         return __get_raid_index(cache->flags);
6589 }
6590
6591 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6592         [BTRFS_RAID_RAID10]     = "raid10",
6593         [BTRFS_RAID_RAID1]      = "raid1",
6594         [BTRFS_RAID_DUP]        = "dup",
6595         [BTRFS_RAID_RAID0]      = "raid0",
6596         [BTRFS_RAID_SINGLE]     = "single",
6597         [BTRFS_RAID_RAID5]      = "raid5",
6598         [BTRFS_RAID_RAID6]      = "raid6",
6599 };
6600
6601 static const char *get_raid_name(enum btrfs_raid_types type)
6602 {
6603         if (type >= BTRFS_NR_RAID_TYPES)
6604                 return NULL;
6605
6606         return btrfs_raid_type_names[type];
6607 }
6608
6609 enum btrfs_loop_type {
6610         LOOP_CACHING_NOWAIT = 0,
6611         LOOP_CACHING_WAIT = 1,
6612         LOOP_ALLOC_CHUNK = 2,
6613         LOOP_NO_EMPTY_SIZE = 3,
6614 };
6615
6616 static inline void
6617 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6618                        int delalloc)
6619 {
6620         if (delalloc)
6621                 down_read(&cache->data_rwsem);
6622 }
6623
6624 static inline void
6625 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6626                        int delalloc)
6627 {
6628         btrfs_get_block_group(cache);
6629         if (delalloc)
6630                 down_read(&cache->data_rwsem);
6631 }
6632
6633 static struct btrfs_block_group_cache *
6634 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6635                    struct btrfs_free_cluster *cluster,
6636                    int delalloc)
6637 {
6638         struct btrfs_block_group_cache *used_bg;
6639         bool locked = false;
6640 again:
6641         spin_lock(&cluster->refill_lock);
6642         if (locked) {
6643                 if (used_bg == cluster->block_group)
6644                         return used_bg;
6645
6646                 up_read(&used_bg->data_rwsem);
6647                 btrfs_put_block_group(used_bg);
6648         }
6649
6650         used_bg = cluster->block_group;
6651         if (!used_bg)
6652                 return NULL;
6653
6654         if (used_bg == block_group)
6655                 return used_bg;
6656
6657         btrfs_get_block_group(used_bg);
6658
6659         if (!delalloc)
6660                 return used_bg;
6661
6662         if (down_read_trylock(&used_bg->data_rwsem))
6663                 return used_bg;
6664
6665         spin_unlock(&cluster->refill_lock);
6666         down_read(&used_bg->data_rwsem);
6667         locked = true;
6668         goto again;
6669 }
6670
6671 static inline void
6672 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6673                          int delalloc)
6674 {
6675         if (delalloc)
6676                 up_read(&cache->data_rwsem);
6677         btrfs_put_block_group(cache);
6678 }
6679
6680 /*
6681  * walks the btree of allocated extents and find a hole of a given size.
6682  * The key ins is changed to record the hole:
6683  * ins->objectid == start position
6684  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6685  * ins->offset == the size of the hole.
6686  * Any available blocks before search_start are skipped.
6687  *
6688  * If there is no suitable free space, we will record the max size of
6689  * the free space extent currently.
6690  */
6691 static noinline int find_free_extent(struct btrfs_root *orig_root,
6692                                      u64 num_bytes, u64 empty_size,
6693                                      u64 hint_byte, struct btrfs_key *ins,
6694                                      u64 flags, int delalloc)
6695 {
6696         int ret = 0;
6697         struct btrfs_root *root = orig_root->fs_info->extent_root;
6698         struct btrfs_free_cluster *last_ptr = NULL;
6699         struct btrfs_block_group_cache *block_group = NULL;
6700         u64 search_start = 0;
6701         u64 max_extent_size = 0;
6702         int empty_cluster = 2 * 1024 * 1024;
6703         struct btrfs_space_info *space_info;
6704         int loop = 0;
6705         int index = __get_raid_index(flags);
6706         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6707                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6708         bool failed_cluster_refill = false;
6709         bool failed_alloc = false;
6710         bool use_cluster = true;
6711         bool have_caching_bg = false;
6712
6713         WARN_ON(num_bytes < root->sectorsize);
6714         ins->type = BTRFS_EXTENT_ITEM_KEY;
6715         ins->objectid = 0;
6716         ins->offset = 0;
6717
6718         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6719
6720         space_info = __find_space_info(root->fs_info, flags);
6721         if (!space_info) {
6722                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6723                 return -ENOSPC;
6724         }
6725
6726         /*
6727          * If the space info is for both data and metadata it means we have a
6728          * small filesystem and we can't use the clustering stuff.
6729          */
6730         if (btrfs_mixed_space_info(space_info))
6731                 use_cluster = false;
6732
6733         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6734                 last_ptr = &root->fs_info->meta_alloc_cluster;
6735                 if (!btrfs_test_opt(root, SSD))
6736                         empty_cluster = 64 * 1024;
6737         }
6738
6739         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6740             btrfs_test_opt(root, SSD)) {
6741                 last_ptr = &root->fs_info->data_alloc_cluster;
6742         }
6743
6744         if (last_ptr) {
6745                 spin_lock(&last_ptr->lock);
6746                 if (last_ptr->block_group)
6747                         hint_byte = last_ptr->window_start;
6748                 spin_unlock(&last_ptr->lock);
6749         }
6750
6751         search_start = max(search_start, first_logical_byte(root, 0));
6752         search_start = max(search_start, hint_byte);
6753
6754         if (!last_ptr)
6755                 empty_cluster = 0;
6756
6757         if (search_start == hint_byte) {
6758                 block_group = btrfs_lookup_block_group(root->fs_info,
6759                                                        search_start);
6760                 /*
6761                  * we don't want to use the block group if it doesn't match our
6762                  * allocation bits, or if its not cached.
6763                  *
6764                  * However if we are re-searching with an ideal block group
6765                  * picked out then we don't care that the block group is cached.
6766                  */
6767                 if (block_group && block_group_bits(block_group, flags) &&
6768                     block_group->cached != BTRFS_CACHE_NO) {
6769                         down_read(&space_info->groups_sem);
6770                         if (list_empty(&block_group->list) ||
6771                             block_group->ro) {
6772                                 /*
6773                                  * someone is removing this block group,
6774                                  * we can't jump into the have_block_group
6775                                  * target because our list pointers are not
6776                                  * valid
6777                                  */
6778                                 btrfs_put_block_group(block_group);
6779                                 up_read(&space_info->groups_sem);
6780                         } else {
6781                                 index = get_block_group_index(block_group);
6782                                 btrfs_lock_block_group(block_group, delalloc);
6783                                 goto have_block_group;
6784                         }
6785                 } else if (block_group) {
6786                         btrfs_put_block_group(block_group);
6787                 }
6788         }
6789 search:
6790         have_caching_bg = false;
6791         down_read(&space_info->groups_sem);
6792         list_for_each_entry(block_group, &space_info->block_groups[index],
6793                             list) {
6794                 u64 offset;
6795                 int cached;
6796
6797                 btrfs_grab_block_group(block_group, delalloc);
6798                 search_start = block_group->key.objectid;
6799
6800                 /*
6801                  * this can happen if we end up cycling through all the
6802                  * raid types, but we want to make sure we only allocate
6803                  * for the proper type.
6804                  */
6805                 if (!block_group_bits(block_group, flags)) {
6806                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6807                                 BTRFS_BLOCK_GROUP_RAID1 |
6808                                 BTRFS_BLOCK_GROUP_RAID5 |
6809                                 BTRFS_BLOCK_GROUP_RAID6 |
6810                                 BTRFS_BLOCK_GROUP_RAID10;
6811
6812                         /*
6813                          * if they asked for extra copies and this block group
6814                          * doesn't provide them, bail.  This does allow us to
6815                          * fill raid0 from raid1.
6816                          */
6817                         if ((flags & extra) && !(block_group->flags & extra))
6818                                 goto loop;
6819                 }
6820
6821 have_block_group:
6822                 cached = block_group_cache_done(block_group);
6823                 if (unlikely(!cached)) {
6824                         ret = cache_block_group(block_group, 0);
6825                         BUG_ON(ret < 0);
6826                         ret = 0;
6827                 }
6828
6829                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6830                         goto loop;
6831                 if (unlikely(block_group->ro))
6832                         goto loop;
6833
6834                 /*
6835                  * Ok we want to try and use the cluster allocator, so
6836                  * lets look there
6837                  */
6838                 if (last_ptr) {
6839                         struct btrfs_block_group_cache *used_block_group;
6840                         unsigned long aligned_cluster;
6841                         /*
6842                          * the refill lock keeps out other
6843                          * people trying to start a new cluster
6844                          */
6845                         used_block_group = btrfs_lock_cluster(block_group,
6846                                                               last_ptr,
6847                                                               delalloc);
6848                         if (!used_block_group)
6849                                 goto refill_cluster;
6850
6851                         if (used_block_group != block_group &&
6852                             (used_block_group->ro ||
6853                              !block_group_bits(used_block_group, flags)))
6854                                 goto release_cluster;
6855
6856                         offset = btrfs_alloc_from_cluster(used_block_group,
6857                                                 last_ptr,
6858                                                 num_bytes,
6859                                                 used_block_group->key.objectid,
6860                                                 &max_extent_size);
6861                         if (offset) {
6862                                 /* we have a block, we're done */
6863                                 spin_unlock(&last_ptr->refill_lock);
6864                                 trace_btrfs_reserve_extent_cluster(root,
6865                                                 used_block_group,
6866                                                 search_start, num_bytes);
6867                                 if (used_block_group != block_group) {
6868                                         btrfs_release_block_group(block_group,
6869                                                                   delalloc);
6870                                         block_group = used_block_group;
6871                                 }
6872                                 goto checks;
6873                         }
6874
6875                         WARN_ON(last_ptr->block_group != used_block_group);
6876 release_cluster:
6877                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6878                          * set up a new clusters, so lets just skip it
6879                          * and let the allocator find whatever block
6880                          * it can find.  If we reach this point, we
6881                          * will have tried the cluster allocator
6882                          * plenty of times and not have found
6883                          * anything, so we are likely way too
6884                          * fragmented for the clustering stuff to find
6885                          * anything.
6886                          *
6887                          * However, if the cluster is taken from the
6888                          * current block group, release the cluster
6889                          * first, so that we stand a better chance of
6890                          * succeeding in the unclustered
6891                          * allocation.  */
6892                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6893                             used_block_group != block_group) {
6894                                 spin_unlock(&last_ptr->refill_lock);
6895                                 btrfs_release_block_group(used_block_group,
6896                                                           delalloc);
6897                                 goto unclustered_alloc;
6898                         }
6899
6900                         /*
6901                          * this cluster didn't work out, free it and
6902                          * start over
6903                          */
6904                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6905
6906                         if (used_block_group != block_group)
6907                                 btrfs_release_block_group(used_block_group,
6908                                                           delalloc);
6909 refill_cluster:
6910                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6911                                 spin_unlock(&last_ptr->refill_lock);
6912                                 goto unclustered_alloc;
6913                         }
6914
6915                         aligned_cluster = max_t(unsigned long,
6916                                                 empty_cluster + empty_size,
6917                                               block_group->full_stripe_len);
6918
6919                         /* allocate a cluster in this block group */
6920                         ret = btrfs_find_space_cluster(root, block_group,
6921                                                        last_ptr, search_start,
6922                                                        num_bytes,
6923                                                        aligned_cluster);
6924                         if (ret == 0) {
6925                                 /*
6926                                  * now pull our allocation out of this
6927                                  * cluster
6928                                  */
6929                                 offset = btrfs_alloc_from_cluster(block_group,
6930                                                         last_ptr,
6931                                                         num_bytes,
6932                                                         search_start,
6933                                                         &max_extent_size);
6934                                 if (offset) {
6935                                         /* we found one, proceed */
6936                                         spin_unlock(&last_ptr->refill_lock);
6937                                         trace_btrfs_reserve_extent_cluster(root,
6938                                                 block_group, search_start,
6939                                                 num_bytes);
6940                                         goto checks;
6941                                 }
6942                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6943                                    && !failed_cluster_refill) {
6944                                 spin_unlock(&last_ptr->refill_lock);
6945
6946                                 failed_cluster_refill = true;
6947                                 wait_block_group_cache_progress(block_group,
6948                                        num_bytes + empty_cluster + empty_size);
6949                                 goto have_block_group;
6950                         }
6951
6952                         /*
6953                          * at this point we either didn't find a cluster
6954                          * or we weren't able to allocate a block from our
6955                          * cluster.  Free the cluster we've been trying
6956                          * to use, and go to the next block group
6957                          */
6958                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6959                         spin_unlock(&last_ptr->refill_lock);
6960                         goto loop;
6961                 }
6962
6963 unclustered_alloc:
6964                 spin_lock(&block_group->free_space_ctl->tree_lock);
6965                 if (cached &&
6966                     block_group->free_space_ctl->free_space <
6967                     num_bytes + empty_cluster + empty_size) {
6968                         if (block_group->free_space_ctl->free_space >
6969                             max_extent_size)
6970                                 max_extent_size =
6971                                         block_group->free_space_ctl->free_space;
6972                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6973                         goto loop;
6974                 }
6975                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6976
6977                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6978                                                     num_bytes, empty_size,
6979                                                     &max_extent_size);
6980                 /*
6981                  * If we didn't find a chunk, and we haven't failed on this
6982                  * block group before, and this block group is in the middle of
6983                  * caching and we are ok with waiting, then go ahead and wait
6984                  * for progress to be made, and set failed_alloc to true.
6985                  *
6986                  * If failed_alloc is true then we've already waited on this
6987                  * block group once and should move on to the next block group.
6988                  */
6989                 if (!offset && !failed_alloc && !cached &&
6990                     loop > LOOP_CACHING_NOWAIT) {
6991                         wait_block_group_cache_progress(block_group,
6992                                                 num_bytes + empty_size);
6993                         failed_alloc = true;
6994                         goto have_block_group;
6995                 } else if (!offset) {
6996                         if (!cached)
6997                                 have_caching_bg = true;
6998                         goto loop;
6999                 }
7000 checks:
7001                 search_start = ALIGN(offset, root->stripesize);
7002
7003                 /* move on to the next group */
7004                 if (search_start + num_bytes >
7005                     block_group->key.objectid + block_group->key.offset) {
7006                         btrfs_add_free_space(block_group, offset, num_bytes);
7007                         goto loop;
7008                 }
7009
7010                 if (offset < search_start)
7011                         btrfs_add_free_space(block_group, offset,
7012                                              search_start - offset);
7013                 BUG_ON(offset > search_start);
7014
7015                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7016                                                   alloc_type, delalloc);
7017                 if (ret == -EAGAIN) {
7018                         btrfs_add_free_space(block_group, offset, num_bytes);
7019                         goto loop;
7020                 }
7021
7022                 /* we are all good, lets return */
7023                 ins->objectid = search_start;
7024                 ins->offset = num_bytes;
7025
7026                 trace_btrfs_reserve_extent(orig_root, block_group,
7027                                            search_start, num_bytes);
7028                 btrfs_release_block_group(block_group, delalloc);
7029                 break;
7030 loop:
7031                 failed_cluster_refill = false;
7032                 failed_alloc = false;
7033                 BUG_ON(index != get_block_group_index(block_group));
7034                 btrfs_release_block_group(block_group, delalloc);
7035         }
7036         up_read(&space_info->groups_sem);
7037
7038         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7039                 goto search;
7040
7041         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7042                 goto search;
7043
7044         /*
7045          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7046          *                      caching kthreads as we move along
7047          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7048          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7049          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7050          *                      again
7051          */
7052         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7053                 index = 0;
7054                 loop++;
7055                 if (loop == LOOP_ALLOC_CHUNK) {
7056                         struct btrfs_trans_handle *trans;
7057                         int exist = 0;
7058
7059                         trans = current->journal_info;
7060                         if (trans)
7061                                 exist = 1;
7062                         else
7063                                 trans = btrfs_join_transaction(root);
7064
7065                         if (IS_ERR(trans)) {
7066                                 ret = PTR_ERR(trans);
7067                                 goto out;
7068                         }
7069
7070                         ret = do_chunk_alloc(trans, root, flags,
7071                                              CHUNK_ALLOC_FORCE);
7072                         /*
7073                          * Do not bail out on ENOSPC since we
7074                          * can do more things.
7075                          */
7076                         if (ret < 0 && ret != -ENOSPC)
7077                                 btrfs_abort_transaction(trans,
7078                                                         root, ret);
7079                         else
7080                                 ret = 0;
7081                         if (!exist)
7082                                 btrfs_end_transaction(trans, root);
7083                         if (ret)
7084                                 goto out;
7085                 }
7086
7087                 if (loop == LOOP_NO_EMPTY_SIZE) {
7088                         empty_size = 0;
7089                         empty_cluster = 0;
7090                 }
7091
7092                 goto search;
7093         } else if (!ins->objectid) {
7094                 ret = -ENOSPC;
7095         } else if (ins->objectid) {
7096                 ret = 0;
7097         }
7098 out:
7099         if (ret == -ENOSPC)
7100                 ins->offset = max_extent_size;
7101         return ret;
7102 }
7103
7104 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7105                             int dump_block_groups)
7106 {
7107         struct btrfs_block_group_cache *cache;
7108         int index = 0;
7109
7110         spin_lock(&info->lock);
7111         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7112                info->flags,
7113                info->total_bytes - info->bytes_used - info->bytes_pinned -
7114                info->bytes_reserved - info->bytes_readonly,
7115                (info->full) ? "" : "not ");
7116         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7117                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7118                info->total_bytes, info->bytes_used, info->bytes_pinned,
7119                info->bytes_reserved, info->bytes_may_use,
7120                info->bytes_readonly);
7121         spin_unlock(&info->lock);
7122
7123         if (!dump_block_groups)
7124                 return;
7125
7126         down_read(&info->groups_sem);
7127 again:
7128         list_for_each_entry(cache, &info->block_groups[index], list) {
7129                 spin_lock(&cache->lock);
7130                 printk(KERN_INFO "BTRFS: "
7131                            "block group %llu has %llu bytes, "
7132                            "%llu used %llu pinned %llu reserved %s\n",
7133                        cache->key.objectid, cache->key.offset,
7134                        btrfs_block_group_used(&cache->item), cache->pinned,
7135                        cache->reserved, cache->ro ? "[readonly]" : "");
7136                 btrfs_dump_free_space(cache, bytes);
7137                 spin_unlock(&cache->lock);
7138         }
7139         if (++index < BTRFS_NR_RAID_TYPES)
7140                 goto again;
7141         up_read(&info->groups_sem);
7142 }
7143
7144 int btrfs_reserve_extent(struct btrfs_root *root,
7145                          u64 num_bytes, u64 min_alloc_size,
7146                          u64 empty_size, u64 hint_byte,
7147                          struct btrfs_key *ins, int is_data, int delalloc)
7148 {
7149         bool final_tried = false;
7150         u64 flags;
7151         int ret;
7152
7153         flags = btrfs_get_alloc_profile(root, is_data);
7154 again:
7155         WARN_ON(num_bytes < root->sectorsize);
7156         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7157                                flags, delalloc);
7158
7159         if (ret == -ENOSPC) {
7160                 if (!final_tried && ins->offset) {
7161                         num_bytes = min(num_bytes >> 1, ins->offset);
7162                         num_bytes = round_down(num_bytes, root->sectorsize);
7163                         num_bytes = max(num_bytes, min_alloc_size);
7164                         if (num_bytes == min_alloc_size)
7165                                 final_tried = true;
7166                         goto again;
7167                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7168                         struct btrfs_space_info *sinfo;
7169
7170                         sinfo = __find_space_info(root->fs_info, flags);
7171                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7172                                 flags, num_bytes);
7173                         if (sinfo)
7174                                 dump_space_info(sinfo, num_bytes, 1);
7175                 }
7176         }
7177
7178         return ret;
7179 }
7180
7181 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7182                                         u64 start, u64 len,
7183                                         int pin, int delalloc)
7184 {
7185         struct btrfs_block_group_cache *cache;
7186         int ret = 0;
7187
7188         cache = btrfs_lookup_block_group(root->fs_info, start);
7189         if (!cache) {
7190                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7191                         start);
7192                 return -ENOSPC;
7193         }
7194
7195         if (pin)
7196                 pin_down_extent(root, cache, start, len, 1);
7197         else {
7198                 if (btrfs_test_opt(root, DISCARD))
7199                         ret = btrfs_discard_extent(root, start, len, NULL);
7200                 btrfs_add_free_space(cache, start, len);
7201                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7202         }
7203
7204         btrfs_put_block_group(cache);
7205
7206         trace_btrfs_reserved_extent_free(root, start, len);
7207
7208         return ret;
7209 }
7210
7211 int btrfs_free_reserved_extent(struct btrfs_root *root,
7212                                u64 start, u64 len, int delalloc)
7213 {
7214         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7215 }
7216
7217 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7218                                        u64 start, u64 len)
7219 {
7220         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7221 }
7222
7223 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7224                                       struct btrfs_root *root,
7225                                       u64 parent, u64 root_objectid,
7226                                       u64 flags, u64 owner, u64 offset,
7227                                       struct btrfs_key *ins, int ref_mod)
7228 {
7229         int ret;
7230         struct btrfs_fs_info *fs_info = root->fs_info;
7231         struct btrfs_extent_item *extent_item;
7232         struct btrfs_extent_inline_ref *iref;
7233         struct btrfs_path *path;
7234         struct extent_buffer *leaf;
7235         int type;
7236         u32 size;
7237
7238         if (parent > 0)
7239                 type = BTRFS_SHARED_DATA_REF_KEY;
7240         else
7241                 type = BTRFS_EXTENT_DATA_REF_KEY;
7242
7243         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7244
7245         path = btrfs_alloc_path();
7246         if (!path)
7247                 return -ENOMEM;
7248
7249         path->leave_spinning = 1;
7250         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7251                                       ins, size);
7252         if (ret) {
7253                 btrfs_free_path(path);
7254                 return ret;
7255         }
7256
7257         leaf = path->nodes[0];
7258         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7259                                      struct btrfs_extent_item);
7260         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7261         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7262         btrfs_set_extent_flags(leaf, extent_item,
7263                                flags | BTRFS_EXTENT_FLAG_DATA);
7264
7265         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7266         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7267         if (parent > 0) {
7268                 struct btrfs_shared_data_ref *ref;
7269                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7270                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7271                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7272         } else {
7273                 struct btrfs_extent_data_ref *ref;
7274                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7275                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7276                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7277                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7278                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7279         }
7280
7281         btrfs_mark_buffer_dirty(path->nodes[0]);
7282         btrfs_free_path(path);
7283
7284         /* Always set parent to 0 here since its exclusive anyway. */
7285         ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7286                                       ins->objectid, ins->offset,
7287                                       BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7288         if (ret)
7289                 return ret;
7290
7291         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7292         if (ret) { /* -ENOENT, logic error */
7293                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7294                         ins->objectid, ins->offset);
7295                 BUG();
7296         }
7297         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7298         return ret;
7299 }
7300
7301 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7302                                      struct btrfs_root *root,
7303                                      u64 parent, u64 root_objectid,
7304                                      u64 flags, struct btrfs_disk_key *key,
7305                                      int level, struct btrfs_key *ins,
7306                                      int no_quota)
7307 {
7308         int ret;
7309         struct btrfs_fs_info *fs_info = root->fs_info;
7310         struct btrfs_extent_item *extent_item;
7311         struct btrfs_tree_block_info *block_info;
7312         struct btrfs_extent_inline_ref *iref;
7313         struct btrfs_path *path;
7314         struct extent_buffer *leaf;
7315         u32 size = sizeof(*extent_item) + sizeof(*iref);
7316         u64 num_bytes = ins->offset;
7317         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7318                                                  SKINNY_METADATA);
7319
7320         if (!skinny_metadata)
7321                 size += sizeof(*block_info);
7322
7323         path = btrfs_alloc_path();
7324         if (!path) {
7325                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7326                                                    root->nodesize);
7327                 return -ENOMEM;
7328         }
7329
7330         path->leave_spinning = 1;
7331         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7332                                       ins, size);
7333         if (ret) {
7334                 btrfs_free_path(path);
7335                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7336                                                    root->nodesize);
7337                 return ret;
7338         }
7339
7340         leaf = path->nodes[0];
7341         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7342                                      struct btrfs_extent_item);
7343         btrfs_set_extent_refs(leaf, extent_item, 1);
7344         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7345         btrfs_set_extent_flags(leaf, extent_item,
7346                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7347
7348         if (skinny_metadata) {
7349                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7350                 num_bytes = root->nodesize;
7351         } else {
7352                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7353                 btrfs_set_tree_block_key(leaf, block_info, key);
7354                 btrfs_set_tree_block_level(leaf, block_info, level);
7355                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7356         }
7357
7358         if (parent > 0) {
7359                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7360                 btrfs_set_extent_inline_ref_type(leaf, iref,
7361                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7362                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7363         } else {
7364                 btrfs_set_extent_inline_ref_type(leaf, iref,
7365                                                  BTRFS_TREE_BLOCK_REF_KEY);
7366                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7367         }
7368
7369         btrfs_mark_buffer_dirty(leaf);
7370         btrfs_free_path(path);
7371
7372         if (!no_quota) {
7373                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7374                                               ins->objectid, num_bytes,
7375                                               BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7376                 if (ret)
7377                         return ret;
7378         }
7379
7380         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7381                                  1);
7382         if (ret) { /* -ENOENT, logic error */
7383                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7384                         ins->objectid, ins->offset);
7385                 BUG();
7386         }
7387
7388         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7389         return ret;
7390 }
7391
7392 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7393                                      struct btrfs_root *root,
7394                                      u64 root_objectid, u64 owner,
7395                                      u64 offset, struct btrfs_key *ins)
7396 {
7397         int ret;
7398
7399         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7400
7401         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7402                                          ins->offset, 0,
7403                                          root_objectid, owner, offset,
7404                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7405         return ret;
7406 }
7407
7408 /*
7409  * this is used by the tree logging recovery code.  It records that
7410  * an extent has been allocated and makes sure to clear the free
7411  * space cache bits as well
7412  */
7413 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7414                                    struct btrfs_root *root,
7415                                    u64 root_objectid, u64 owner, u64 offset,
7416                                    struct btrfs_key *ins)
7417 {
7418         int ret;
7419         struct btrfs_block_group_cache *block_group;
7420
7421         /*
7422          * Mixed block groups will exclude before processing the log so we only
7423          * need to do the exlude dance if this fs isn't mixed.
7424          */
7425         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7426                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7427                 if (ret)
7428                         return ret;
7429         }
7430
7431         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7432         if (!block_group)
7433                 return -EINVAL;
7434
7435         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7436                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7437         BUG_ON(ret); /* logic error */
7438         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7439                                          0, owner, offset, ins, 1);
7440         btrfs_put_block_group(block_group);
7441         return ret;
7442 }
7443
7444 static struct extent_buffer *
7445 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7446                       u64 bytenr, int level)
7447 {
7448         struct extent_buffer *buf;
7449
7450         buf = btrfs_find_create_tree_block(root, bytenr);
7451         if (!buf)
7452                 return ERR_PTR(-ENOMEM);
7453         btrfs_set_header_generation(buf, trans->transid);
7454         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7455         btrfs_tree_lock(buf);
7456         clean_tree_block(trans, root->fs_info, buf);
7457         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7458
7459         btrfs_set_lock_blocking(buf);
7460         btrfs_set_buffer_uptodate(buf);
7461
7462         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7463                 buf->log_index = root->log_transid % 2;
7464                 /*
7465                  * we allow two log transactions at a time, use different
7466                  * EXENT bit to differentiate dirty pages.
7467                  */
7468                 if (buf->log_index == 0)
7469                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7470                                         buf->start + buf->len - 1, GFP_NOFS);
7471                 else
7472                         set_extent_new(&root->dirty_log_pages, buf->start,
7473                                         buf->start + buf->len - 1, GFP_NOFS);
7474         } else {
7475                 buf->log_index = -1;
7476                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7477                          buf->start + buf->len - 1, GFP_NOFS);
7478         }
7479         trans->blocks_used++;
7480         /* this returns a buffer locked for blocking */
7481         return buf;
7482 }
7483
7484 static struct btrfs_block_rsv *
7485 use_block_rsv(struct btrfs_trans_handle *trans,
7486               struct btrfs_root *root, u32 blocksize)
7487 {
7488         struct btrfs_block_rsv *block_rsv;
7489         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7490         int ret;
7491         bool global_updated = false;
7492
7493         block_rsv = get_block_rsv(trans, root);
7494
7495         if (unlikely(block_rsv->size == 0))
7496                 goto try_reserve;
7497 again:
7498         ret = block_rsv_use_bytes(block_rsv, blocksize);
7499         if (!ret)
7500                 return block_rsv;
7501
7502         if (block_rsv->failfast)
7503                 return ERR_PTR(ret);
7504
7505         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7506                 global_updated = true;
7507                 update_global_block_rsv(root->fs_info);
7508                 goto again;
7509         }
7510
7511         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7512                 static DEFINE_RATELIMIT_STATE(_rs,
7513                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7514                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7515                 if (__ratelimit(&_rs))
7516                         WARN(1, KERN_DEBUG
7517                                 "BTRFS: block rsv returned %d\n", ret);
7518         }
7519 try_reserve:
7520         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7521                                      BTRFS_RESERVE_NO_FLUSH);
7522         if (!ret)
7523                 return block_rsv;
7524         /*
7525          * If we couldn't reserve metadata bytes try and use some from
7526          * the global reserve if its space type is the same as the global
7527          * reservation.
7528          */
7529         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7530             block_rsv->space_info == global_rsv->space_info) {
7531                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7532                 if (!ret)
7533                         return global_rsv;
7534         }
7535         return ERR_PTR(ret);
7536 }
7537
7538 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7539                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7540 {
7541         block_rsv_add_bytes(block_rsv, blocksize, 0);
7542         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7543 }
7544
7545 /*
7546  * finds a free extent and does all the dirty work required for allocation
7547  * returns the key for the extent through ins, and a tree buffer for
7548  * the first block of the extent through buf.
7549  *
7550  * returns the tree buffer or NULL.
7551  */
7552 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7553                                         struct btrfs_root *root,
7554                                         u64 parent, u64 root_objectid,
7555                                         struct btrfs_disk_key *key, int level,
7556                                         u64 hint, u64 empty_size)
7557 {
7558         struct btrfs_key ins;
7559         struct btrfs_block_rsv *block_rsv;
7560         struct extent_buffer *buf;
7561         u64 flags = 0;
7562         int ret;
7563         u32 blocksize = root->nodesize;
7564         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7565                                                  SKINNY_METADATA);
7566
7567         if (btrfs_test_is_dummy_root(root)) {
7568                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7569                                             level);
7570                 if (!IS_ERR(buf))
7571                         root->alloc_bytenr += blocksize;
7572                 return buf;
7573         }
7574
7575         block_rsv = use_block_rsv(trans, root, blocksize);
7576         if (IS_ERR(block_rsv))
7577                 return ERR_CAST(block_rsv);
7578
7579         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7580                                    empty_size, hint, &ins, 0, 0);
7581         if (ret) {
7582                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7583                 return ERR_PTR(ret);
7584         }
7585
7586         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
7587         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
7588
7589         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7590                 if (parent == 0)
7591                         parent = ins.objectid;
7592                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7593         } else
7594                 BUG_ON(parent > 0);
7595
7596         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7597                 struct btrfs_delayed_extent_op *extent_op;
7598                 extent_op = btrfs_alloc_delayed_extent_op();
7599                 BUG_ON(!extent_op); /* -ENOMEM */
7600                 if (key)
7601                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7602                 else
7603                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7604                 extent_op->flags_to_set = flags;
7605                 if (skinny_metadata)
7606                         extent_op->update_key = 0;
7607                 else
7608                         extent_op->update_key = 1;
7609                 extent_op->update_flags = 1;
7610                 extent_op->is_data = 0;
7611                 extent_op->level = level;
7612
7613                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7614                                         ins.objectid,
7615                                         ins.offset, parent, root_objectid,
7616                                         level, BTRFS_ADD_DELAYED_EXTENT,
7617                                         extent_op, 0);
7618                 BUG_ON(ret); /* -ENOMEM */
7619         }
7620         return buf;
7621 }
7622
7623 struct walk_control {
7624         u64 refs[BTRFS_MAX_LEVEL];
7625         u64 flags[BTRFS_MAX_LEVEL];
7626         struct btrfs_key update_progress;
7627         int stage;
7628         int level;
7629         int shared_level;
7630         int update_ref;
7631         int keep_locks;
7632         int reada_slot;
7633         int reada_count;
7634         int for_reloc;
7635 };
7636
7637 #define DROP_REFERENCE  1
7638 #define UPDATE_BACKREF  2
7639
7640 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7641                                      struct btrfs_root *root,
7642                                      struct walk_control *wc,
7643                                      struct btrfs_path *path)
7644 {
7645         u64 bytenr;
7646         u64 generation;
7647         u64 refs;
7648         u64 flags;
7649         u32 nritems;
7650         u32 blocksize;
7651         struct btrfs_key key;
7652         struct extent_buffer *eb;
7653         int ret;
7654         int slot;
7655         int nread = 0;
7656
7657         if (path->slots[wc->level] < wc->reada_slot) {
7658                 wc->reada_count = wc->reada_count * 2 / 3;
7659                 wc->reada_count = max(wc->reada_count, 2);
7660         } else {
7661                 wc->reada_count = wc->reada_count * 3 / 2;
7662                 wc->reada_count = min_t(int, wc->reada_count,
7663                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7664         }
7665
7666         eb = path->nodes[wc->level];
7667         nritems = btrfs_header_nritems(eb);
7668         blocksize = root->nodesize;
7669
7670         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7671                 if (nread >= wc->reada_count)
7672                         break;
7673
7674                 cond_resched();
7675                 bytenr = btrfs_node_blockptr(eb, slot);
7676                 generation = btrfs_node_ptr_generation(eb, slot);
7677
7678                 if (slot == path->slots[wc->level])
7679                         goto reada;
7680
7681                 if (wc->stage == UPDATE_BACKREF &&
7682                     generation <= root->root_key.offset)
7683                         continue;
7684
7685                 /* We don't lock the tree block, it's OK to be racy here */
7686                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7687                                                wc->level - 1, 1, &refs,
7688                                                &flags);
7689                 /* We don't care about errors in readahead. */
7690                 if (ret < 0)
7691                         continue;
7692                 BUG_ON(refs == 0);
7693
7694                 if (wc->stage == DROP_REFERENCE) {
7695                         if (refs == 1)
7696                                 goto reada;
7697
7698                         if (wc->level == 1 &&
7699                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7700                                 continue;
7701                         if (!wc->update_ref ||
7702                             generation <= root->root_key.offset)
7703                                 continue;
7704                         btrfs_node_key_to_cpu(eb, &key, slot);
7705                         ret = btrfs_comp_cpu_keys(&key,
7706                                                   &wc->update_progress);
7707                         if (ret < 0)
7708                                 continue;
7709                 } else {
7710                         if (wc->level == 1 &&
7711                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7712                                 continue;
7713                 }
7714 reada:
7715                 readahead_tree_block(root, bytenr);
7716                 nread++;
7717         }
7718         wc->reada_slot = slot;
7719 }
7720
7721 static int account_leaf_items(struct btrfs_trans_handle *trans,
7722                               struct btrfs_root *root,
7723                               struct extent_buffer *eb)
7724 {
7725         int nr = btrfs_header_nritems(eb);
7726         int i, extent_type, ret;
7727         struct btrfs_key key;
7728         struct btrfs_file_extent_item *fi;
7729         u64 bytenr, num_bytes;
7730
7731         for (i = 0; i < nr; i++) {
7732                 btrfs_item_key_to_cpu(eb, &key, i);
7733
7734                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7735                         continue;
7736
7737                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7738                 /* filter out non qgroup-accountable extents  */
7739                 extent_type = btrfs_file_extent_type(eb, fi);
7740
7741                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7742                         continue;
7743
7744                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7745                 if (!bytenr)
7746                         continue;
7747
7748                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7749
7750                 ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7751                                               root->objectid,
7752                                               bytenr, num_bytes,
7753                                               BTRFS_QGROUP_OPER_SUB_SUBTREE, 0);
7754                 if (ret)
7755                         return ret;
7756         }
7757         return 0;
7758 }
7759
7760 /*
7761  * Walk up the tree from the bottom, freeing leaves and any interior
7762  * nodes which have had all slots visited. If a node (leaf or
7763  * interior) is freed, the node above it will have it's slot
7764  * incremented. The root node will never be freed.
7765  *
7766  * At the end of this function, we should have a path which has all
7767  * slots incremented to the next position for a search. If we need to
7768  * read a new node it will be NULL and the node above it will have the
7769  * correct slot selected for a later read.
7770  *
7771  * If we increment the root nodes slot counter past the number of
7772  * elements, 1 is returned to signal completion of the search.
7773  */
7774 static int adjust_slots_upwards(struct btrfs_root *root,
7775                                 struct btrfs_path *path, int root_level)
7776 {
7777         int level = 0;
7778         int nr, slot;
7779         struct extent_buffer *eb;
7780
7781         if (root_level == 0)
7782                 return 1;
7783
7784         while (level <= root_level) {
7785                 eb = path->nodes[level];
7786                 nr = btrfs_header_nritems(eb);
7787                 path->slots[level]++;
7788                 slot = path->slots[level];
7789                 if (slot >= nr || level == 0) {
7790                         /*
7791                          * Don't free the root -  we will detect this
7792                          * condition after our loop and return a
7793                          * positive value for caller to stop walking the tree.
7794                          */
7795                         if (level != root_level) {
7796                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7797                                 path->locks[level] = 0;
7798
7799                                 free_extent_buffer(eb);
7800                                 path->nodes[level] = NULL;
7801                                 path->slots[level] = 0;
7802                         }
7803                 } else {
7804                         /*
7805                          * We have a valid slot to walk back down
7806                          * from. Stop here so caller can process these
7807                          * new nodes.
7808                          */
7809                         break;
7810                 }
7811
7812                 level++;
7813         }
7814
7815         eb = path->nodes[root_level];
7816         if (path->slots[root_level] >= btrfs_header_nritems(eb))
7817                 return 1;
7818
7819         return 0;
7820 }
7821
7822 /*
7823  * root_eb is the subtree root and is locked before this function is called.
7824  */
7825 static int account_shared_subtree(struct btrfs_trans_handle *trans,
7826                                   struct btrfs_root *root,
7827                                   struct extent_buffer *root_eb,
7828                                   u64 root_gen,
7829                                   int root_level)
7830 {
7831         int ret = 0;
7832         int level;
7833         struct extent_buffer *eb = root_eb;
7834         struct btrfs_path *path = NULL;
7835
7836         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
7837         BUG_ON(root_eb == NULL);
7838
7839         if (!root->fs_info->quota_enabled)
7840                 return 0;
7841
7842         if (!extent_buffer_uptodate(root_eb)) {
7843                 ret = btrfs_read_buffer(root_eb, root_gen);
7844                 if (ret)
7845                         goto out;
7846         }
7847
7848         if (root_level == 0) {
7849                 ret = account_leaf_items(trans, root, root_eb);
7850                 goto out;
7851         }
7852
7853         path = btrfs_alloc_path();
7854         if (!path)
7855                 return -ENOMEM;
7856
7857         /*
7858          * Walk down the tree.  Missing extent blocks are filled in as
7859          * we go. Metadata is accounted every time we read a new
7860          * extent block.
7861          *
7862          * When we reach a leaf, we account for file extent items in it,
7863          * walk back up the tree (adjusting slot pointers as we go)
7864          * and restart the search process.
7865          */
7866         extent_buffer_get(root_eb); /* For path */
7867         path->nodes[root_level] = root_eb;
7868         path->slots[root_level] = 0;
7869         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
7870 walk_down:
7871         level = root_level;
7872         while (level >= 0) {
7873                 if (path->nodes[level] == NULL) {
7874                         int parent_slot;
7875                         u64 child_gen;
7876                         u64 child_bytenr;
7877
7878                         /* We need to get child blockptr/gen from
7879                          * parent before we can read it. */
7880                         eb = path->nodes[level + 1];
7881                         parent_slot = path->slots[level + 1];
7882                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
7883                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
7884
7885                         eb = read_tree_block(root, child_bytenr, child_gen);
7886                         if (!eb || !extent_buffer_uptodate(eb)) {
7887                                 ret = -EIO;
7888                                 goto out;
7889                         }
7890
7891                         path->nodes[level] = eb;
7892                         path->slots[level] = 0;
7893
7894                         btrfs_tree_read_lock(eb);
7895                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
7896                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
7897
7898                         ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7899                                                 root->objectid,
7900                                                 child_bytenr,
7901                                                 root->nodesize,
7902                                                 BTRFS_QGROUP_OPER_SUB_SUBTREE,
7903                                                 0);
7904                         if (ret)
7905                                 goto out;
7906
7907                 }
7908
7909                 if (level == 0) {
7910                         ret = account_leaf_items(trans, root, path->nodes[level]);
7911                         if (ret)
7912                                 goto out;
7913
7914                         /* Nonzero return here means we completed our search */
7915                         ret = adjust_slots_upwards(root, path, root_level);
7916                         if (ret)
7917                                 break;
7918
7919                         /* Restart search with new slots */
7920                         goto walk_down;
7921                 }
7922
7923                 level--;
7924         }
7925
7926         ret = 0;
7927 out:
7928         btrfs_free_path(path);
7929
7930         return ret;
7931 }
7932
7933 /*
7934  * helper to process tree block while walking down the tree.
7935  *
7936  * when wc->stage == UPDATE_BACKREF, this function updates
7937  * back refs for pointers in the block.
7938  *
7939  * NOTE: return value 1 means we should stop walking down.
7940  */
7941 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7942                                    struct btrfs_root *root,
7943                                    struct btrfs_path *path,
7944                                    struct walk_control *wc, int lookup_info)
7945 {
7946         int level = wc->level;
7947         struct extent_buffer *eb = path->nodes[level];
7948         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7949         int ret;
7950
7951         if (wc->stage == UPDATE_BACKREF &&
7952             btrfs_header_owner(eb) != root->root_key.objectid)
7953                 return 1;
7954
7955         /*
7956          * when reference count of tree block is 1, it won't increase
7957          * again. once full backref flag is set, we never clear it.
7958          */
7959         if (lookup_info &&
7960             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7961              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7962                 BUG_ON(!path->locks[level]);
7963                 ret = btrfs_lookup_extent_info(trans, root,
7964                                                eb->start, level, 1,
7965                                                &wc->refs[level],
7966                                                &wc->flags[level]);
7967                 BUG_ON(ret == -ENOMEM);
7968                 if (ret)
7969                         return ret;
7970                 BUG_ON(wc->refs[level] == 0);
7971         }
7972
7973         if (wc->stage == DROP_REFERENCE) {
7974                 if (wc->refs[level] > 1)
7975                         return 1;
7976
7977                 if (path->locks[level] && !wc->keep_locks) {
7978                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7979                         path->locks[level] = 0;
7980                 }
7981                 return 0;
7982         }
7983
7984         /* wc->stage == UPDATE_BACKREF */
7985         if (!(wc->flags[level] & flag)) {
7986                 BUG_ON(!path->locks[level]);
7987                 ret = btrfs_inc_ref(trans, root, eb, 1);
7988                 BUG_ON(ret); /* -ENOMEM */
7989                 ret = btrfs_dec_ref(trans, root, eb, 0);
7990                 BUG_ON(ret); /* -ENOMEM */
7991                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7992                                                   eb->len, flag,
7993                                                   btrfs_header_level(eb), 0);
7994                 BUG_ON(ret); /* -ENOMEM */
7995                 wc->flags[level] |= flag;
7996         }
7997
7998         /*
7999          * the block is shared by multiple trees, so it's not good to
8000          * keep the tree lock
8001          */
8002         if (path->locks[level] && level > 0) {
8003                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8004                 path->locks[level] = 0;
8005         }
8006         return 0;
8007 }
8008
8009 /*
8010  * helper to process tree block pointer.
8011  *
8012  * when wc->stage == DROP_REFERENCE, this function checks
8013  * reference count of the block pointed to. if the block
8014  * is shared and we need update back refs for the subtree
8015  * rooted at the block, this function changes wc->stage to
8016  * UPDATE_BACKREF. if the block is shared and there is no
8017  * need to update back, this function drops the reference
8018  * to the block.
8019  *
8020  * NOTE: return value 1 means we should stop walking down.
8021  */
8022 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8023                                  struct btrfs_root *root,
8024                                  struct btrfs_path *path,
8025                                  struct walk_control *wc, int *lookup_info)
8026 {
8027         u64 bytenr;
8028         u64 generation;
8029         u64 parent;
8030         u32 blocksize;
8031         struct btrfs_key key;
8032         struct extent_buffer *next;
8033         int level = wc->level;
8034         int reada = 0;
8035         int ret = 0;
8036         bool need_account = false;
8037
8038         generation = btrfs_node_ptr_generation(path->nodes[level],
8039                                                path->slots[level]);
8040         /*
8041          * if the lower level block was created before the snapshot
8042          * was created, we know there is no need to update back refs
8043          * for the subtree
8044          */
8045         if (wc->stage == UPDATE_BACKREF &&
8046             generation <= root->root_key.offset) {
8047                 *lookup_info = 1;
8048                 return 1;
8049         }
8050
8051         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8052         blocksize = root->nodesize;
8053
8054         next = btrfs_find_tree_block(root->fs_info, bytenr);
8055         if (!next) {
8056                 next = btrfs_find_create_tree_block(root, bytenr);
8057                 if (!next)
8058                         return -ENOMEM;
8059                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8060                                                level - 1);
8061                 reada = 1;
8062         }
8063         btrfs_tree_lock(next);
8064         btrfs_set_lock_blocking(next);
8065
8066         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8067                                        &wc->refs[level - 1],
8068                                        &wc->flags[level - 1]);
8069         if (ret < 0) {
8070                 btrfs_tree_unlock(next);
8071                 return ret;
8072         }
8073
8074         if (unlikely(wc->refs[level - 1] == 0)) {
8075                 btrfs_err(root->fs_info, "Missing references.");
8076                 BUG();
8077         }
8078         *lookup_info = 0;
8079
8080         if (wc->stage == DROP_REFERENCE) {
8081                 if (wc->refs[level - 1] > 1) {
8082                         need_account = true;
8083                         if (level == 1 &&
8084                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8085                                 goto skip;
8086
8087                         if (!wc->update_ref ||
8088                             generation <= root->root_key.offset)
8089                                 goto skip;
8090
8091                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8092                                               path->slots[level]);
8093                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8094                         if (ret < 0)
8095                                 goto skip;
8096
8097                         wc->stage = UPDATE_BACKREF;
8098                         wc->shared_level = level - 1;
8099                 }
8100         } else {
8101                 if (level == 1 &&
8102                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8103                         goto skip;
8104         }
8105
8106         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8107                 btrfs_tree_unlock(next);
8108                 free_extent_buffer(next);
8109                 next = NULL;
8110                 *lookup_info = 1;
8111         }
8112
8113         if (!next) {
8114                 if (reada && level == 1)
8115                         reada_walk_down(trans, root, wc, path);
8116                 next = read_tree_block(root, bytenr, generation);
8117                 if (!next || !extent_buffer_uptodate(next)) {
8118                         free_extent_buffer(next);
8119                         return -EIO;
8120                 }
8121                 btrfs_tree_lock(next);
8122                 btrfs_set_lock_blocking(next);
8123         }
8124
8125         level--;
8126         BUG_ON(level != btrfs_header_level(next));
8127         path->nodes[level] = next;
8128         path->slots[level] = 0;
8129         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8130         wc->level = level;
8131         if (wc->level == 1)
8132                 wc->reada_slot = 0;
8133         return 0;
8134 skip:
8135         wc->refs[level - 1] = 0;
8136         wc->flags[level - 1] = 0;
8137         if (wc->stage == DROP_REFERENCE) {
8138                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8139                         parent = path->nodes[level]->start;
8140                 } else {
8141                         BUG_ON(root->root_key.objectid !=
8142                                btrfs_header_owner(path->nodes[level]));
8143                         parent = 0;
8144                 }
8145
8146                 if (need_account) {
8147                         ret = account_shared_subtree(trans, root, next,
8148                                                      generation, level - 1);
8149                         if (ret) {
8150                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
8151                                         "%d accounting shared subtree. Quota "
8152                                         "is out of sync, rescan required.\n",
8153                                         root->fs_info->sb->s_id, ret);
8154                         }
8155                 }
8156                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8157                                 root->root_key.objectid, level - 1, 0, 0);
8158                 BUG_ON(ret); /* -ENOMEM */
8159         }
8160         btrfs_tree_unlock(next);
8161         free_extent_buffer(next);
8162         *lookup_info = 1;
8163         return 1;
8164 }
8165
8166 /*
8167  * helper to process tree block while walking up the tree.
8168  *
8169  * when wc->stage == DROP_REFERENCE, this function drops
8170  * reference count on the block.
8171  *
8172  * when wc->stage == UPDATE_BACKREF, this function changes
8173  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8174  * to UPDATE_BACKREF previously while processing the block.
8175  *
8176  * NOTE: return value 1 means we should stop walking up.
8177  */
8178 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8179                                  struct btrfs_root *root,
8180                                  struct btrfs_path *path,
8181                                  struct walk_control *wc)
8182 {
8183         int ret;
8184         int level = wc->level;
8185         struct extent_buffer *eb = path->nodes[level];
8186         u64 parent = 0;
8187
8188         if (wc->stage == UPDATE_BACKREF) {
8189                 BUG_ON(wc->shared_level < level);
8190                 if (level < wc->shared_level)
8191                         goto out;
8192
8193                 ret = find_next_key(path, level + 1, &wc->update_progress);
8194                 if (ret > 0)
8195                         wc->update_ref = 0;
8196
8197                 wc->stage = DROP_REFERENCE;
8198                 wc->shared_level = -1;
8199                 path->slots[level] = 0;
8200
8201                 /*
8202                  * check reference count again if the block isn't locked.
8203                  * we should start walking down the tree again if reference
8204                  * count is one.
8205                  */
8206                 if (!path->locks[level]) {
8207                         BUG_ON(level == 0);
8208                         btrfs_tree_lock(eb);
8209                         btrfs_set_lock_blocking(eb);
8210                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8211
8212                         ret = btrfs_lookup_extent_info(trans, root,
8213                                                        eb->start, level, 1,
8214                                                        &wc->refs[level],
8215                                                        &wc->flags[level]);
8216                         if (ret < 0) {
8217                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8218                                 path->locks[level] = 0;
8219                                 return ret;
8220                         }
8221                         BUG_ON(wc->refs[level] == 0);
8222                         if (wc->refs[level] == 1) {
8223                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8224                                 path->locks[level] = 0;
8225                                 return 1;
8226                         }
8227                 }
8228         }
8229
8230         /* wc->stage == DROP_REFERENCE */
8231         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8232
8233         if (wc->refs[level] == 1) {
8234                 if (level == 0) {
8235                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8236                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8237                         else
8238                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8239                         BUG_ON(ret); /* -ENOMEM */
8240                         ret = account_leaf_items(trans, root, eb);
8241                         if (ret) {
8242                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
8243                                         "%d accounting leaf items. Quota "
8244                                         "is out of sync, rescan required.\n",
8245                                         root->fs_info->sb->s_id, ret);
8246                         }
8247                 }
8248                 /* make block locked assertion in clean_tree_block happy */
8249                 if (!path->locks[level] &&
8250                     btrfs_header_generation(eb) == trans->transid) {
8251                         btrfs_tree_lock(eb);
8252                         btrfs_set_lock_blocking(eb);
8253                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8254                 }
8255                 clean_tree_block(trans, root->fs_info, eb);
8256         }
8257
8258         if (eb == root->node) {
8259                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8260                         parent = eb->start;
8261                 else
8262                         BUG_ON(root->root_key.objectid !=
8263                                btrfs_header_owner(eb));
8264         } else {
8265                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8266                         parent = path->nodes[level + 1]->start;
8267                 else
8268                         BUG_ON(root->root_key.objectid !=
8269                                btrfs_header_owner(path->nodes[level + 1]));
8270         }
8271
8272         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8273 out:
8274         wc->refs[level] = 0;
8275         wc->flags[level] = 0;
8276         return 0;
8277 }
8278
8279 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8280                                    struct btrfs_root *root,
8281                                    struct btrfs_path *path,
8282                                    struct walk_control *wc)
8283 {
8284         int level = wc->level;
8285         int lookup_info = 1;
8286         int ret;
8287
8288         while (level >= 0) {
8289                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8290                 if (ret > 0)
8291                         break;
8292
8293                 if (level == 0)
8294                         break;
8295
8296                 if (path->slots[level] >=
8297                     btrfs_header_nritems(path->nodes[level]))
8298                         break;
8299
8300                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8301                 if (ret > 0) {
8302                         path->slots[level]++;
8303                         continue;
8304                 } else if (ret < 0)
8305                         return ret;
8306                 level = wc->level;
8307         }
8308         return 0;
8309 }
8310
8311 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8312                                  struct btrfs_root *root,
8313                                  struct btrfs_path *path,
8314                                  struct walk_control *wc, int max_level)
8315 {
8316         int level = wc->level;
8317         int ret;
8318
8319         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8320         while (level < max_level && path->nodes[level]) {
8321                 wc->level = level;
8322                 if (path->slots[level] + 1 <
8323                     btrfs_header_nritems(path->nodes[level])) {
8324                         path->slots[level]++;
8325                         return 0;
8326                 } else {
8327                         ret = walk_up_proc(trans, root, path, wc);
8328                         if (ret > 0)
8329                                 return 0;
8330
8331                         if (path->locks[level]) {
8332                                 btrfs_tree_unlock_rw(path->nodes[level],
8333                                                      path->locks[level]);
8334                                 path->locks[level] = 0;
8335                         }
8336                         free_extent_buffer(path->nodes[level]);
8337                         path->nodes[level] = NULL;
8338                         level++;
8339                 }
8340         }
8341         return 1;
8342 }
8343
8344 /*
8345  * drop a subvolume tree.
8346  *
8347  * this function traverses the tree freeing any blocks that only
8348  * referenced by the tree.
8349  *
8350  * when a shared tree block is found. this function decreases its
8351  * reference count by one. if update_ref is true, this function
8352  * also make sure backrefs for the shared block and all lower level
8353  * blocks are properly updated.
8354  *
8355  * If called with for_reloc == 0, may exit early with -EAGAIN
8356  */
8357 int btrfs_drop_snapshot(struct btrfs_root *root,
8358                          struct btrfs_block_rsv *block_rsv, int update_ref,
8359                          int for_reloc)
8360 {
8361         struct btrfs_path *path;
8362         struct btrfs_trans_handle *trans;
8363         struct btrfs_root *tree_root = root->fs_info->tree_root;
8364         struct btrfs_root_item *root_item = &root->root_item;
8365         struct walk_control *wc;
8366         struct btrfs_key key;
8367         int err = 0;
8368         int ret;
8369         int level;
8370         bool root_dropped = false;
8371
8372         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8373
8374         path = btrfs_alloc_path();
8375         if (!path) {
8376                 err = -ENOMEM;
8377                 goto out;
8378         }
8379
8380         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8381         if (!wc) {
8382                 btrfs_free_path(path);
8383                 err = -ENOMEM;
8384                 goto out;
8385         }
8386
8387         trans = btrfs_start_transaction(tree_root, 0);
8388         if (IS_ERR(trans)) {
8389                 err = PTR_ERR(trans);
8390                 goto out_free;
8391         }
8392
8393         if (block_rsv)
8394                 trans->block_rsv = block_rsv;
8395
8396         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8397                 level = btrfs_header_level(root->node);
8398                 path->nodes[level] = btrfs_lock_root_node(root);
8399                 btrfs_set_lock_blocking(path->nodes[level]);
8400                 path->slots[level] = 0;
8401                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8402                 memset(&wc->update_progress, 0,
8403                        sizeof(wc->update_progress));
8404         } else {
8405                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8406                 memcpy(&wc->update_progress, &key,
8407                        sizeof(wc->update_progress));
8408
8409                 level = root_item->drop_level;
8410                 BUG_ON(level == 0);
8411                 path->lowest_level = level;
8412                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8413                 path->lowest_level = 0;
8414                 if (ret < 0) {
8415                         err = ret;
8416                         goto out_end_trans;
8417                 }
8418                 WARN_ON(ret > 0);
8419
8420                 /*
8421                  * unlock our path, this is safe because only this
8422                  * function is allowed to delete this snapshot
8423                  */
8424                 btrfs_unlock_up_safe(path, 0);
8425
8426                 level = btrfs_header_level(root->node);
8427                 while (1) {
8428                         btrfs_tree_lock(path->nodes[level]);
8429                         btrfs_set_lock_blocking(path->nodes[level]);
8430                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8431
8432                         ret = btrfs_lookup_extent_info(trans, root,
8433                                                 path->nodes[level]->start,
8434                                                 level, 1, &wc->refs[level],
8435                                                 &wc->flags[level]);
8436                         if (ret < 0) {
8437                                 err = ret;
8438                                 goto out_end_trans;
8439                         }
8440                         BUG_ON(wc->refs[level] == 0);
8441
8442                         if (level == root_item->drop_level)
8443                                 break;
8444
8445                         btrfs_tree_unlock(path->nodes[level]);
8446                         path->locks[level] = 0;
8447                         WARN_ON(wc->refs[level] != 1);
8448                         level--;
8449                 }
8450         }
8451
8452         wc->level = level;
8453         wc->shared_level = -1;
8454         wc->stage = DROP_REFERENCE;
8455         wc->update_ref = update_ref;
8456         wc->keep_locks = 0;
8457         wc->for_reloc = for_reloc;
8458         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8459
8460         while (1) {
8461
8462                 ret = walk_down_tree(trans, root, path, wc);
8463                 if (ret < 0) {
8464                         err = ret;
8465                         break;
8466                 }
8467
8468                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8469                 if (ret < 0) {
8470                         err = ret;
8471                         break;
8472                 }
8473
8474                 if (ret > 0) {
8475                         BUG_ON(wc->stage != DROP_REFERENCE);
8476                         break;
8477                 }
8478
8479                 if (wc->stage == DROP_REFERENCE) {
8480                         level = wc->level;
8481                         btrfs_node_key(path->nodes[level],
8482                                        &root_item->drop_progress,
8483                                        path->slots[level]);
8484                         root_item->drop_level = level;
8485                 }
8486
8487                 BUG_ON(wc->level == 0);
8488                 if (btrfs_should_end_transaction(trans, tree_root) ||
8489                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8490                         ret = btrfs_update_root(trans, tree_root,
8491                                                 &root->root_key,
8492                                                 root_item);
8493                         if (ret) {
8494                                 btrfs_abort_transaction(trans, tree_root, ret);
8495                                 err = ret;
8496                                 goto out_end_trans;
8497                         }
8498
8499                         /*
8500                          * Qgroup update accounting is run from
8501                          * delayed ref handling. This usually works
8502                          * out because delayed refs are normally the
8503                          * only way qgroup updates are added. However,
8504                          * we may have added updates during our tree
8505                          * walk so run qgroups here to make sure we
8506                          * don't lose any updates.
8507                          */
8508                         ret = btrfs_delayed_qgroup_accounting(trans,
8509                                                               root->fs_info);
8510                         if (ret)
8511                                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8512                                                    "running qgroup updates "
8513                                                    "during snapshot delete. "
8514                                                    "Quota is out of sync, "
8515                                                    "rescan required.\n", ret);
8516
8517                         btrfs_end_transaction_throttle(trans, tree_root);
8518                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8519                                 pr_debug("BTRFS: drop snapshot early exit\n");
8520                                 err = -EAGAIN;
8521                                 goto out_free;
8522                         }
8523
8524                         trans = btrfs_start_transaction(tree_root, 0);
8525                         if (IS_ERR(trans)) {
8526                                 err = PTR_ERR(trans);
8527                                 goto out_free;
8528                         }
8529                         if (block_rsv)
8530                                 trans->block_rsv = block_rsv;
8531                 }
8532         }
8533         btrfs_release_path(path);
8534         if (err)
8535                 goto out_end_trans;
8536
8537         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8538         if (ret) {
8539                 btrfs_abort_transaction(trans, tree_root, ret);
8540                 goto out_end_trans;
8541         }
8542
8543         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8544                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8545                                       NULL, NULL);
8546                 if (ret < 0) {
8547                         btrfs_abort_transaction(trans, tree_root, ret);
8548                         err = ret;
8549                         goto out_end_trans;
8550                 } else if (ret > 0) {
8551                         /* if we fail to delete the orphan item this time
8552                          * around, it'll get picked up the next time.
8553                          *
8554                          * The most common failure here is just -ENOENT.
8555                          */
8556                         btrfs_del_orphan_item(trans, tree_root,
8557                                               root->root_key.objectid);
8558                 }
8559         }
8560
8561         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8562                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
8563         } else {
8564                 free_extent_buffer(root->node);
8565                 free_extent_buffer(root->commit_root);
8566                 btrfs_put_fs_root(root);
8567         }
8568         root_dropped = true;
8569 out_end_trans:
8570         ret = btrfs_delayed_qgroup_accounting(trans, tree_root->fs_info);
8571         if (ret)
8572                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8573                                    "running qgroup updates "
8574                                    "during snapshot delete. "
8575                                    "Quota is out of sync, "
8576                                    "rescan required.\n", ret);
8577
8578         btrfs_end_transaction_throttle(trans, tree_root);
8579 out_free:
8580         kfree(wc);
8581         btrfs_free_path(path);
8582 out:
8583         /*
8584          * So if we need to stop dropping the snapshot for whatever reason we
8585          * need to make sure to add it back to the dead root list so that we
8586          * keep trying to do the work later.  This also cleans up roots if we
8587          * don't have it in the radix (like when we recover after a power fail
8588          * or unmount) so we don't leak memory.
8589          */
8590         if (!for_reloc && root_dropped == false)
8591                 btrfs_add_dead_root(root);
8592         if (err && err != -EAGAIN)
8593                 btrfs_std_error(root->fs_info, err);
8594         return err;
8595 }
8596
8597 /*
8598  * drop subtree rooted at tree block 'node'.
8599  *
8600  * NOTE: this function will unlock and release tree block 'node'
8601  * only used by relocation code
8602  */
8603 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8604                         struct btrfs_root *root,
8605                         struct extent_buffer *node,
8606                         struct extent_buffer *parent)
8607 {
8608         struct btrfs_path *path;
8609         struct walk_control *wc;
8610         int level;
8611         int parent_level;
8612         int ret = 0;
8613         int wret;
8614
8615         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8616
8617         path = btrfs_alloc_path();
8618         if (!path)
8619                 return -ENOMEM;
8620
8621         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8622         if (!wc) {
8623                 btrfs_free_path(path);
8624                 return -ENOMEM;
8625         }
8626
8627         btrfs_assert_tree_locked(parent);
8628         parent_level = btrfs_header_level(parent);
8629         extent_buffer_get(parent);
8630         path->nodes[parent_level] = parent;
8631         path->slots[parent_level] = btrfs_header_nritems(parent);
8632
8633         btrfs_assert_tree_locked(node);
8634         level = btrfs_header_level(node);
8635         path->nodes[level] = node;
8636         path->slots[level] = 0;
8637         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8638
8639         wc->refs[parent_level] = 1;
8640         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8641         wc->level = level;
8642         wc->shared_level = -1;
8643         wc->stage = DROP_REFERENCE;
8644         wc->update_ref = 0;
8645         wc->keep_locks = 1;
8646         wc->for_reloc = 1;
8647         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8648
8649         while (1) {
8650                 wret = walk_down_tree(trans, root, path, wc);
8651                 if (wret < 0) {
8652                         ret = wret;
8653                         break;
8654                 }
8655
8656                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8657                 if (wret < 0)
8658                         ret = wret;
8659                 if (wret != 0)
8660                         break;
8661         }
8662
8663         kfree(wc);
8664         btrfs_free_path(path);
8665         return ret;
8666 }
8667
8668 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8669 {
8670         u64 num_devices;
8671         u64 stripped;
8672
8673         /*
8674          * if restripe for this chunk_type is on pick target profile and
8675          * return, otherwise do the usual balance
8676          */
8677         stripped = get_restripe_target(root->fs_info, flags);
8678         if (stripped)
8679                 return extended_to_chunk(stripped);
8680
8681         num_devices = root->fs_info->fs_devices->rw_devices;
8682
8683         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8684                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8685                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8686
8687         if (num_devices == 1) {
8688                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8689                 stripped = flags & ~stripped;
8690
8691                 /* turn raid0 into single device chunks */
8692                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8693                         return stripped;
8694
8695                 /* turn mirroring into duplication */
8696                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8697                              BTRFS_BLOCK_GROUP_RAID10))
8698                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8699         } else {
8700                 /* they already had raid on here, just return */
8701                 if (flags & stripped)
8702                         return flags;
8703
8704                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8705                 stripped = flags & ~stripped;
8706
8707                 /* switch duplicated blocks with raid1 */
8708                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8709                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8710
8711                 /* this is drive concat, leave it alone */
8712         }
8713
8714         return flags;
8715 }
8716
8717 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8718 {
8719         struct btrfs_space_info *sinfo = cache->space_info;
8720         u64 num_bytes;
8721         u64 min_allocable_bytes;
8722         int ret = -ENOSPC;
8723
8724
8725         /*
8726          * We need some metadata space and system metadata space for
8727          * allocating chunks in some corner cases until we force to set
8728          * it to be readonly.
8729          */
8730         if ((sinfo->flags &
8731              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8732             !force)
8733                 min_allocable_bytes = 1 * 1024 * 1024;
8734         else
8735                 min_allocable_bytes = 0;
8736
8737         spin_lock(&sinfo->lock);
8738         spin_lock(&cache->lock);
8739
8740         if (cache->ro) {
8741                 ret = 0;
8742                 goto out;
8743         }
8744
8745         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8746                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8747
8748         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8749             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8750             min_allocable_bytes <= sinfo->total_bytes) {
8751                 sinfo->bytes_readonly += num_bytes;
8752                 cache->ro = 1;
8753                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
8754                 ret = 0;
8755         }
8756 out:
8757         spin_unlock(&cache->lock);
8758         spin_unlock(&sinfo->lock);
8759         return ret;
8760 }
8761
8762 int btrfs_set_block_group_ro(struct btrfs_root *root,
8763                              struct btrfs_block_group_cache *cache)
8764
8765 {
8766         struct btrfs_trans_handle *trans;
8767         u64 alloc_flags;
8768         int ret;
8769
8770         BUG_ON(cache->ro);
8771
8772 again:
8773         trans = btrfs_join_transaction(root);
8774         if (IS_ERR(trans))
8775                 return PTR_ERR(trans);
8776
8777         /*
8778          * we're not allowed to set block groups readonly after the dirty
8779          * block groups cache has started writing.  If it already started,
8780          * back off and let this transaction commit
8781          */
8782         mutex_lock(&root->fs_info->ro_block_group_mutex);
8783         if (trans->transaction->dirty_bg_run) {
8784                 u64 transid = trans->transid;
8785
8786                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
8787                 btrfs_end_transaction(trans, root);
8788
8789                 ret = btrfs_wait_for_commit(root, transid);
8790                 if (ret)
8791                         return ret;
8792                 goto again;
8793         }
8794
8795
8796         ret = set_block_group_ro(cache, 0);
8797         if (!ret)
8798                 goto out;
8799         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8800         ret = do_chunk_alloc(trans, root, alloc_flags,
8801                              CHUNK_ALLOC_FORCE);
8802         if (ret < 0)
8803                 goto out;
8804         ret = set_block_group_ro(cache, 0);
8805 out:
8806         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
8807                 alloc_flags = update_block_group_flags(root, cache->flags);
8808                 check_system_chunk(trans, root, alloc_flags);
8809         }
8810         mutex_unlock(&root->fs_info->ro_block_group_mutex);
8811
8812         btrfs_end_transaction(trans, root);
8813         return ret;
8814 }
8815
8816 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8817                             struct btrfs_root *root, u64 type)
8818 {
8819         u64 alloc_flags = get_alloc_profile(root, type);
8820         return do_chunk_alloc(trans, root, alloc_flags,
8821                               CHUNK_ALLOC_FORCE);
8822 }
8823
8824 /*
8825  * helper to account the unused space of all the readonly block group in the
8826  * space_info. takes mirrors into account.
8827  */
8828 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8829 {
8830         struct btrfs_block_group_cache *block_group;
8831         u64 free_bytes = 0;
8832         int factor;
8833
8834         /* It's df, we don't care if it's racey */
8835         if (list_empty(&sinfo->ro_bgs))
8836                 return 0;
8837
8838         spin_lock(&sinfo->lock);
8839         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
8840                 spin_lock(&block_group->lock);
8841
8842                 if (!block_group->ro) {
8843                         spin_unlock(&block_group->lock);
8844                         continue;
8845                 }
8846
8847                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8848                                           BTRFS_BLOCK_GROUP_RAID10 |
8849                                           BTRFS_BLOCK_GROUP_DUP))
8850                         factor = 2;
8851                 else
8852                         factor = 1;
8853
8854                 free_bytes += (block_group->key.offset -
8855                                btrfs_block_group_used(&block_group->item)) *
8856                                factor;
8857
8858                 spin_unlock(&block_group->lock);
8859         }
8860         spin_unlock(&sinfo->lock);
8861
8862         return free_bytes;
8863 }
8864
8865 void btrfs_set_block_group_rw(struct btrfs_root *root,
8866                               struct btrfs_block_group_cache *cache)
8867 {
8868         struct btrfs_space_info *sinfo = cache->space_info;
8869         u64 num_bytes;
8870
8871         BUG_ON(!cache->ro);
8872
8873         spin_lock(&sinfo->lock);
8874         spin_lock(&cache->lock);
8875         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8876                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8877         sinfo->bytes_readonly -= num_bytes;
8878         cache->ro = 0;
8879         list_del_init(&cache->ro_list);
8880         spin_unlock(&cache->lock);
8881         spin_unlock(&sinfo->lock);
8882 }
8883
8884 /*
8885  * checks to see if its even possible to relocate this block group.
8886  *
8887  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8888  * ok to go ahead and try.
8889  */
8890 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8891 {
8892         struct btrfs_block_group_cache *block_group;
8893         struct btrfs_space_info *space_info;
8894         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8895         struct btrfs_device *device;
8896         struct btrfs_trans_handle *trans;
8897         u64 min_free;
8898         u64 dev_min = 1;
8899         u64 dev_nr = 0;
8900         u64 target;
8901         int index;
8902         int full = 0;
8903         int ret = 0;
8904
8905         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8906
8907         /* odd, couldn't find the block group, leave it alone */
8908         if (!block_group)
8909                 return -1;
8910
8911         min_free = btrfs_block_group_used(&block_group->item);
8912
8913         /* no bytes used, we're good */
8914         if (!min_free)
8915                 goto out;
8916
8917         space_info = block_group->space_info;
8918         spin_lock(&space_info->lock);
8919
8920         full = space_info->full;
8921
8922         /*
8923          * if this is the last block group we have in this space, we can't
8924          * relocate it unless we're able to allocate a new chunk below.
8925          *
8926          * Otherwise, we need to make sure we have room in the space to handle
8927          * all of the extents from this block group.  If we can, we're good
8928          */
8929         if ((space_info->total_bytes != block_group->key.offset) &&
8930             (space_info->bytes_used + space_info->bytes_reserved +
8931              space_info->bytes_pinned + space_info->bytes_readonly +
8932              min_free < space_info->total_bytes)) {
8933                 spin_unlock(&space_info->lock);
8934                 goto out;
8935         }
8936         spin_unlock(&space_info->lock);
8937
8938         /*
8939          * ok we don't have enough space, but maybe we have free space on our
8940          * devices to allocate new chunks for relocation, so loop through our
8941          * alloc devices and guess if we have enough space.  if this block
8942          * group is going to be restriped, run checks against the target
8943          * profile instead of the current one.
8944          */
8945         ret = -1;
8946
8947         /*
8948          * index:
8949          *      0: raid10
8950          *      1: raid1
8951          *      2: dup
8952          *      3: raid0
8953          *      4: single
8954          */
8955         target = get_restripe_target(root->fs_info, block_group->flags);
8956         if (target) {
8957                 index = __get_raid_index(extended_to_chunk(target));
8958         } else {
8959                 /*
8960                  * this is just a balance, so if we were marked as full
8961                  * we know there is no space for a new chunk
8962                  */
8963                 if (full)
8964                         goto out;
8965
8966                 index = get_block_group_index(block_group);
8967         }
8968
8969         if (index == BTRFS_RAID_RAID10) {
8970                 dev_min = 4;
8971                 /* Divide by 2 */
8972                 min_free >>= 1;
8973         } else if (index == BTRFS_RAID_RAID1) {
8974                 dev_min = 2;
8975         } else if (index == BTRFS_RAID_DUP) {
8976                 /* Multiply by 2 */
8977                 min_free <<= 1;
8978         } else if (index == BTRFS_RAID_RAID0) {
8979                 dev_min = fs_devices->rw_devices;
8980                 min_free = div64_u64(min_free, dev_min);
8981         }
8982
8983         /* We need to do this so that we can look at pending chunks */
8984         trans = btrfs_join_transaction(root);
8985         if (IS_ERR(trans)) {
8986                 ret = PTR_ERR(trans);
8987                 goto out;
8988         }
8989
8990         mutex_lock(&root->fs_info->chunk_mutex);
8991         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8992                 u64 dev_offset;
8993
8994                 /*
8995                  * check to make sure we can actually find a chunk with enough
8996                  * space to fit our block group in.
8997                  */
8998                 if (device->total_bytes > device->bytes_used + min_free &&
8999                     !device->is_tgtdev_for_dev_replace) {
9000                         ret = find_free_dev_extent(trans, device, min_free,
9001                                                    &dev_offset, NULL);
9002                         if (!ret)
9003                                 dev_nr++;
9004
9005                         if (dev_nr >= dev_min)
9006                                 break;
9007
9008                         ret = -1;
9009                 }
9010         }
9011         mutex_unlock(&root->fs_info->chunk_mutex);
9012         btrfs_end_transaction(trans, root);
9013 out:
9014         btrfs_put_block_group(block_group);
9015         return ret;
9016 }
9017
9018 static int find_first_block_group(struct btrfs_root *root,
9019                 struct btrfs_path *path, struct btrfs_key *key)
9020 {
9021         int ret = 0;
9022         struct btrfs_key found_key;
9023         struct extent_buffer *leaf;
9024         int slot;
9025
9026         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9027         if (ret < 0)
9028                 goto out;
9029
9030         while (1) {
9031                 slot = path->slots[0];
9032                 leaf = path->nodes[0];
9033                 if (slot >= btrfs_header_nritems(leaf)) {
9034                         ret = btrfs_next_leaf(root, path);
9035                         if (ret == 0)
9036                                 continue;
9037                         if (ret < 0)
9038                                 goto out;
9039                         break;
9040                 }
9041                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9042
9043                 if (found_key.objectid >= key->objectid &&
9044                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9045                         ret = 0;
9046                         goto out;
9047                 }
9048                 path->slots[0]++;
9049         }
9050 out:
9051         return ret;
9052 }
9053
9054 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9055 {
9056         struct btrfs_block_group_cache *block_group;
9057         u64 last = 0;
9058
9059         while (1) {
9060                 struct inode *inode;
9061
9062                 block_group = btrfs_lookup_first_block_group(info, last);
9063                 while (block_group) {
9064                         spin_lock(&block_group->lock);
9065                         if (block_group->iref)
9066                                 break;
9067                         spin_unlock(&block_group->lock);
9068                         block_group = next_block_group(info->tree_root,
9069                                                        block_group);
9070                 }
9071                 if (!block_group) {
9072                         if (last == 0)
9073                                 break;
9074                         last = 0;
9075                         continue;
9076                 }
9077
9078                 inode = block_group->inode;
9079                 block_group->iref = 0;
9080                 block_group->inode = NULL;
9081                 spin_unlock(&block_group->lock);
9082                 iput(inode);
9083                 last = block_group->key.objectid + block_group->key.offset;
9084                 btrfs_put_block_group(block_group);
9085         }
9086 }
9087
9088 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9089 {
9090         struct btrfs_block_group_cache *block_group;
9091         struct btrfs_space_info *space_info;
9092         struct btrfs_caching_control *caching_ctl;
9093         struct rb_node *n;
9094
9095         down_write(&info->commit_root_sem);
9096         while (!list_empty(&info->caching_block_groups)) {
9097                 caching_ctl = list_entry(info->caching_block_groups.next,
9098                                          struct btrfs_caching_control, list);
9099                 list_del(&caching_ctl->list);
9100                 put_caching_control(caching_ctl);
9101         }
9102         up_write(&info->commit_root_sem);
9103
9104         spin_lock(&info->unused_bgs_lock);
9105         while (!list_empty(&info->unused_bgs)) {
9106                 block_group = list_first_entry(&info->unused_bgs,
9107                                                struct btrfs_block_group_cache,
9108                                                bg_list);
9109                 list_del_init(&block_group->bg_list);
9110                 btrfs_put_block_group(block_group);
9111         }
9112         spin_unlock(&info->unused_bgs_lock);
9113
9114         spin_lock(&info->block_group_cache_lock);
9115         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9116                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9117                                        cache_node);
9118                 rb_erase(&block_group->cache_node,
9119                          &info->block_group_cache_tree);
9120                 RB_CLEAR_NODE(&block_group->cache_node);
9121                 spin_unlock(&info->block_group_cache_lock);
9122
9123                 down_write(&block_group->space_info->groups_sem);
9124                 list_del(&block_group->list);
9125                 up_write(&block_group->space_info->groups_sem);
9126
9127                 if (block_group->cached == BTRFS_CACHE_STARTED)
9128                         wait_block_group_cache_done(block_group);
9129
9130                 /*
9131                  * We haven't cached this block group, which means we could
9132                  * possibly have excluded extents on this block group.
9133                  */
9134                 if (block_group->cached == BTRFS_CACHE_NO ||
9135                     block_group->cached == BTRFS_CACHE_ERROR)
9136                         free_excluded_extents(info->extent_root, block_group);
9137
9138                 btrfs_remove_free_space_cache(block_group);
9139                 btrfs_put_block_group(block_group);
9140
9141                 spin_lock(&info->block_group_cache_lock);
9142         }
9143         spin_unlock(&info->block_group_cache_lock);
9144
9145         /* now that all the block groups are freed, go through and
9146          * free all the space_info structs.  This is only called during
9147          * the final stages of unmount, and so we know nobody is
9148          * using them.  We call synchronize_rcu() once before we start,
9149          * just to be on the safe side.
9150          */
9151         synchronize_rcu();
9152
9153         release_global_block_rsv(info);
9154
9155         while (!list_empty(&info->space_info)) {
9156                 int i;
9157
9158                 space_info = list_entry(info->space_info.next,
9159                                         struct btrfs_space_info,
9160                                         list);
9161                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9162                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9163                             space_info->bytes_reserved > 0 ||
9164                             space_info->bytes_may_use > 0)) {
9165                                 dump_space_info(space_info, 0, 0);
9166                         }
9167                 }
9168                 list_del(&space_info->list);
9169                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9170                         struct kobject *kobj;
9171                         kobj = space_info->block_group_kobjs[i];
9172                         space_info->block_group_kobjs[i] = NULL;
9173                         if (kobj) {
9174                                 kobject_del(kobj);
9175                                 kobject_put(kobj);
9176                         }
9177                 }
9178                 kobject_del(&space_info->kobj);
9179                 kobject_put(&space_info->kobj);
9180         }
9181         return 0;
9182 }
9183
9184 static void __link_block_group(struct btrfs_space_info *space_info,
9185                                struct btrfs_block_group_cache *cache)
9186 {
9187         int index = get_block_group_index(cache);
9188         bool first = false;
9189
9190         down_write(&space_info->groups_sem);
9191         if (list_empty(&space_info->block_groups[index]))
9192                 first = true;
9193         list_add_tail(&cache->list, &space_info->block_groups[index]);
9194         up_write(&space_info->groups_sem);
9195
9196         if (first) {
9197                 struct raid_kobject *rkobj;
9198                 int ret;
9199
9200                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9201                 if (!rkobj)
9202                         goto out_err;
9203                 rkobj->raid_type = index;
9204                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9205                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9206                                   "%s", get_raid_name(index));
9207                 if (ret) {
9208                         kobject_put(&rkobj->kobj);
9209                         goto out_err;
9210                 }
9211                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9212         }
9213
9214         return;
9215 out_err:
9216         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9217 }
9218
9219 static struct btrfs_block_group_cache *
9220 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9221 {
9222         struct btrfs_block_group_cache *cache;
9223
9224         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9225         if (!cache)
9226                 return NULL;
9227
9228         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9229                                         GFP_NOFS);
9230         if (!cache->free_space_ctl) {
9231                 kfree(cache);
9232                 return NULL;
9233         }
9234
9235         cache->key.objectid = start;
9236         cache->key.offset = size;
9237         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9238
9239         cache->sectorsize = root->sectorsize;
9240         cache->fs_info = root->fs_info;
9241         cache->full_stripe_len = btrfs_full_stripe_len(root,
9242                                                &root->fs_info->mapping_tree,
9243                                                start);
9244         atomic_set(&cache->count, 1);
9245         spin_lock_init(&cache->lock);
9246         init_rwsem(&cache->data_rwsem);
9247         INIT_LIST_HEAD(&cache->list);
9248         INIT_LIST_HEAD(&cache->cluster_list);
9249         INIT_LIST_HEAD(&cache->bg_list);
9250         INIT_LIST_HEAD(&cache->ro_list);
9251         INIT_LIST_HEAD(&cache->dirty_list);
9252         INIT_LIST_HEAD(&cache->io_list);
9253         btrfs_init_free_space_ctl(cache);
9254         atomic_set(&cache->trimming, 0);
9255
9256         return cache;
9257 }
9258
9259 int btrfs_read_block_groups(struct btrfs_root *root)
9260 {
9261         struct btrfs_path *path;
9262         int ret;
9263         struct btrfs_block_group_cache *cache;
9264         struct btrfs_fs_info *info = root->fs_info;
9265         struct btrfs_space_info *space_info;
9266         struct btrfs_key key;
9267         struct btrfs_key found_key;
9268         struct extent_buffer *leaf;
9269         int need_clear = 0;
9270         u64 cache_gen;
9271
9272         root = info->extent_root;
9273         key.objectid = 0;
9274         key.offset = 0;
9275         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9276         path = btrfs_alloc_path();
9277         if (!path)
9278                 return -ENOMEM;
9279         path->reada = 1;
9280
9281         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9282         if (btrfs_test_opt(root, SPACE_CACHE) &&
9283             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9284                 need_clear = 1;
9285         if (btrfs_test_opt(root, CLEAR_CACHE))
9286                 need_clear = 1;
9287
9288         while (1) {
9289                 ret = find_first_block_group(root, path, &key);
9290                 if (ret > 0)
9291                         break;
9292                 if (ret != 0)
9293                         goto error;
9294
9295                 leaf = path->nodes[0];
9296                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9297
9298                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9299                                                        found_key.offset);
9300                 if (!cache) {
9301                         ret = -ENOMEM;
9302                         goto error;
9303                 }
9304
9305                 if (need_clear) {
9306                         /*
9307                          * When we mount with old space cache, we need to
9308                          * set BTRFS_DC_CLEAR and set dirty flag.
9309                          *
9310                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9311                          *    truncate the old free space cache inode and
9312                          *    setup a new one.
9313                          * b) Setting 'dirty flag' makes sure that we flush
9314                          *    the new space cache info onto disk.
9315                          */
9316                         if (btrfs_test_opt(root, SPACE_CACHE))
9317                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9318                 }
9319
9320                 read_extent_buffer(leaf, &cache->item,
9321                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9322                                    sizeof(cache->item));
9323                 cache->flags = btrfs_block_group_flags(&cache->item);
9324
9325                 key.objectid = found_key.objectid + found_key.offset;
9326                 btrfs_release_path(path);
9327
9328                 /*
9329                  * We need to exclude the super stripes now so that the space
9330                  * info has super bytes accounted for, otherwise we'll think
9331                  * we have more space than we actually do.
9332                  */
9333                 ret = exclude_super_stripes(root, cache);
9334                 if (ret) {
9335                         /*
9336                          * We may have excluded something, so call this just in
9337                          * case.
9338                          */
9339                         free_excluded_extents(root, cache);
9340                         btrfs_put_block_group(cache);
9341                         goto error;
9342                 }
9343
9344                 /*
9345                  * check for two cases, either we are full, and therefore
9346                  * don't need to bother with the caching work since we won't
9347                  * find any space, or we are empty, and we can just add all
9348                  * the space in and be done with it.  This saves us _alot_ of
9349                  * time, particularly in the full case.
9350                  */
9351                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9352                         cache->last_byte_to_unpin = (u64)-1;
9353                         cache->cached = BTRFS_CACHE_FINISHED;
9354                         free_excluded_extents(root, cache);
9355                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9356                         cache->last_byte_to_unpin = (u64)-1;
9357                         cache->cached = BTRFS_CACHE_FINISHED;
9358                         add_new_free_space(cache, root->fs_info,
9359                                            found_key.objectid,
9360                                            found_key.objectid +
9361                                            found_key.offset);
9362                         free_excluded_extents(root, cache);
9363                 }
9364
9365                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9366                 if (ret) {
9367                         btrfs_remove_free_space_cache(cache);
9368                         btrfs_put_block_group(cache);
9369                         goto error;
9370                 }
9371
9372                 ret = update_space_info(info, cache->flags, found_key.offset,
9373                                         btrfs_block_group_used(&cache->item),
9374                                         &space_info);
9375                 if (ret) {
9376                         btrfs_remove_free_space_cache(cache);
9377                         spin_lock(&info->block_group_cache_lock);
9378                         rb_erase(&cache->cache_node,
9379                                  &info->block_group_cache_tree);
9380                         RB_CLEAR_NODE(&cache->cache_node);
9381                         spin_unlock(&info->block_group_cache_lock);
9382                         btrfs_put_block_group(cache);
9383                         goto error;
9384                 }
9385
9386                 cache->space_info = space_info;
9387                 spin_lock(&cache->space_info->lock);
9388                 cache->space_info->bytes_readonly += cache->bytes_super;
9389                 spin_unlock(&cache->space_info->lock);
9390
9391                 __link_block_group(space_info, cache);
9392
9393                 set_avail_alloc_bits(root->fs_info, cache->flags);
9394                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9395                         set_block_group_ro(cache, 1);
9396                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9397                         spin_lock(&info->unused_bgs_lock);
9398                         /* Should always be true but just in case. */
9399                         if (list_empty(&cache->bg_list)) {
9400                                 btrfs_get_block_group(cache);
9401                                 list_add_tail(&cache->bg_list,
9402                                               &info->unused_bgs);
9403                         }
9404                         spin_unlock(&info->unused_bgs_lock);
9405                 }
9406         }
9407
9408         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9409                 if (!(get_alloc_profile(root, space_info->flags) &
9410                       (BTRFS_BLOCK_GROUP_RAID10 |
9411                        BTRFS_BLOCK_GROUP_RAID1 |
9412                        BTRFS_BLOCK_GROUP_RAID5 |
9413                        BTRFS_BLOCK_GROUP_RAID6 |
9414                        BTRFS_BLOCK_GROUP_DUP)))
9415                         continue;
9416                 /*
9417                  * avoid allocating from un-mirrored block group if there are
9418                  * mirrored block groups.
9419                  */
9420                 list_for_each_entry(cache,
9421                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9422                                 list)
9423                         set_block_group_ro(cache, 1);
9424                 list_for_each_entry(cache,
9425                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9426                                 list)
9427                         set_block_group_ro(cache, 1);
9428         }
9429
9430         init_global_block_rsv(info);
9431         ret = 0;
9432 error:
9433         btrfs_free_path(path);
9434         return ret;
9435 }
9436
9437 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9438                                        struct btrfs_root *root)
9439 {
9440         struct btrfs_block_group_cache *block_group, *tmp;
9441         struct btrfs_root *extent_root = root->fs_info->extent_root;
9442         struct btrfs_block_group_item item;
9443         struct btrfs_key key;
9444         int ret = 0;
9445
9446         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9447                 if (ret)
9448                         goto next;
9449
9450                 spin_lock(&block_group->lock);
9451                 memcpy(&item, &block_group->item, sizeof(item));
9452                 memcpy(&key, &block_group->key, sizeof(key));
9453                 spin_unlock(&block_group->lock);
9454
9455                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9456                                         sizeof(item));
9457                 if (ret)
9458                         btrfs_abort_transaction(trans, extent_root, ret);
9459                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9460                                                key.objectid, key.offset);
9461                 if (ret)
9462                         btrfs_abort_transaction(trans, extent_root, ret);
9463 next:
9464                 list_del_init(&block_group->bg_list);
9465         }
9466 }
9467
9468 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9469                            struct btrfs_root *root, u64 bytes_used,
9470                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9471                            u64 size)
9472 {
9473         int ret;
9474         struct btrfs_root *extent_root;
9475         struct btrfs_block_group_cache *cache;
9476
9477         extent_root = root->fs_info->extent_root;
9478
9479         btrfs_set_log_full_commit(root->fs_info, trans);
9480
9481         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9482         if (!cache)
9483                 return -ENOMEM;
9484
9485         btrfs_set_block_group_used(&cache->item, bytes_used);
9486         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9487         btrfs_set_block_group_flags(&cache->item, type);
9488
9489         cache->flags = type;
9490         cache->last_byte_to_unpin = (u64)-1;
9491         cache->cached = BTRFS_CACHE_FINISHED;
9492         ret = exclude_super_stripes(root, cache);
9493         if (ret) {
9494                 /*
9495                  * We may have excluded something, so call this just in
9496                  * case.
9497                  */
9498                 free_excluded_extents(root, cache);
9499                 btrfs_put_block_group(cache);
9500                 return ret;
9501         }
9502
9503         add_new_free_space(cache, root->fs_info, chunk_offset,
9504                            chunk_offset + size);
9505
9506         free_excluded_extents(root, cache);
9507
9508         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9509         if (ret) {
9510                 btrfs_remove_free_space_cache(cache);
9511                 btrfs_put_block_group(cache);
9512                 return ret;
9513         }
9514
9515         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9516                                 &cache->space_info);
9517         if (ret) {
9518                 btrfs_remove_free_space_cache(cache);
9519                 spin_lock(&root->fs_info->block_group_cache_lock);
9520                 rb_erase(&cache->cache_node,
9521                          &root->fs_info->block_group_cache_tree);
9522                 RB_CLEAR_NODE(&cache->cache_node);
9523                 spin_unlock(&root->fs_info->block_group_cache_lock);
9524                 btrfs_put_block_group(cache);
9525                 return ret;
9526         }
9527         update_global_block_rsv(root->fs_info);
9528
9529         spin_lock(&cache->space_info->lock);
9530         cache->space_info->bytes_readonly += cache->bytes_super;
9531         spin_unlock(&cache->space_info->lock);
9532
9533         __link_block_group(cache->space_info, cache);
9534
9535         list_add_tail(&cache->bg_list, &trans->new_bgs);
9536
9537         set_avail_alloc_bits(extent_root->fs_info, type);
9538
9539         return 0;
9540 }
9541
9542 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9543 {
9544         u64 extra_flags = chunk_to_extended(flags) &
9545                                 BTRFS_EXTENDED_PROFILE_MASK;
9546
9547         write_seqlock(&fs_info->profiles_lock);
9548         if (flags & BTRFS_BLOCK_GROUP_DATA)
9549                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9550         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9551                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9552         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9553                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9554         write_sequnlock(&fs_info->profiles_lock);
9555 }
9556
9557 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9558                              struct btrfs_root *root, u64 group_start,
9559                              struct extent_map *em)
9560 {
9561         struct btrfs_path *path;
9562         struct btrfs_block_group_cache *block_group;
9563         struct btrfs_free_cluster *cluster;
9564         struct btrfs_root *tree_root = root->fs_info->tree_root;
9565         struct btrfs_key key;
9566         struct inode *inode;
9567         struct kobject *kobj = NULL;
9568         int ret;
9569         int index;
9570         int factor;
9571         struct btrfs_caching_control *caching_ctl = NULL;
9572         bool remove_em;
9573
9574         root = root->fs_info->extent_root;
9575
9576         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9577         BUG_ON(!block_group);
9578         BUG_ON(!block_group->ro);
9579
9580         /*
9581          * Free the reserved super bytes from this block group before
9582          * remove it.
9583          */
9584         free_excluded_extents(root, block_group);
9585
9586         memcpy(&key, &block_group->key, sizeof(key));
9587         index = get_block_group_index(block_group);
9588         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9589                                   BTRFS_BLOCK_GROUP_RAID1 |
9590                                   BTRFS_BLOCK_GROUP_RAID10))
9591                 factor = 2;
9592         else
9593                 factor = 1;
9594
9595         /* make sure this block group isn't part of an allocation cluster */
9596         cluster = &root->fs_info->data_alloc_cluster;
9597         spin_lock(&cluster->refill_lock);
9598         btrfs_return_cluster_to_free_space(block_group, cluster);
9599         spin_unlock(&cluster->refill_lock);
9600
9601         /*
9602          * make sure this block group isn't part of a metadata
9603          * allocation cluster
9604          */
9605         cluster = &root->fs_info->meta_alloc_cluster;
9606         spin_lock(&cluster->refill_lock);
9607         btrfs_return_cluster_to_free_space(block_group, cluster);
9608         spin_unlock(&cluster->refill_lock);
9609
9610         path = btrfs_alloc_path();
9611         if (!path) {
9612                 ret = -ENOMEM;
9613                 goto out;
9614         }
9615
9616         /*
9617          * get the inode first so any iput calls done for the io_list
9618          * aren't the final iput (no unlinks allowed now)
9619          */
9620         inode = lookup_free_space_inode(tree_root, block_group, path);
9621
9622         mutex_lock(&trans->transaction->cache_write_mutex);
9623         /*
9624          * make sure our free spache cache IO is done before remove the
9625          * free space inode
9626          */
9627         spin_lock(&trans->transaction->dirty_bgs_lock);
9628         if (!list_empty(&block_group->io_list)) {
9629                 list_del_init(&block_group->io_list);
9630
9631                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
9632
9633                 spin_unlock(&trans->transaction->dirty_bgs_lock);
9634                 btrfs_wait_cache_io(root, trans, block_group,
9635                                     &block_group->io_ctl, path,
9636                                     block_group->key.objectid);
9637                 btrfs_put_block_group(block_group);
9638                 spin_lock(&trans->transaction->dirty_bgs_lock);
9639         }
9640
9641         if (!list_empty(&block_group->dirty_list)) {
9642                 list_del_init(&block_group->dirty_list);
9643                 btrfs_put_block_group(block_group);
9644         }
9645         spin_unlock(&trans->transaction->dirty_bgs_lock);
9646         mutex_unlock(&trans->transaction->cache_write_mutex);
9647
9648         if (!IS_ERR(inode)) {
9649                 ret = btrfs_orphan_add(trans, inode);
9650                 if (ret) {
9651                         btrfs_add_delayed_iput(inode);
9652                         goto out;
9653                 }
9654                 clear_nlink(inode);
9655                 /* One for the block groups ref */
9656                 spin_lock(&block_group->lock);
9657                 if (block_group->iref) {
9658                         block_group->iref = 0;
9659                         block_group->inode = NULL;
9660                         spin_unlock(&block_group->lock);
9661                         iput(inode);
9662                 } else {
9663                         spin_unlock(&block_group->lock);
9664                 }
9665                 /* One for our lookup ref */
9666                 btrfs_add_delayed_iput(inode);
9667         }
9668
9669         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9670         key.offset = block_group->key.objectid;
9671         key.type = 0;
9672
9673         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9674         if (ret < 0)
9675                 goto out;
9676         if (ret > 0)
9677                 btrfs_release_path(path);
9678         if (ret == 0) {
9679                 ret = btrfs_del_item(trans, tree_root, path);
9680                 if (ret)
9681                         goto out;
9682                 btrfs_release_path(path);
9683         }
9684
9685         spin_lock(&root->fs_info->block_group_cache_lock);
9686         rb_erase(&block_group->cache_node,
9687                  &root->fs_info->block_group_cache_tree);
9688         RB_CLEAR_NODE(&block_group->cache_node);
9689
9690         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9691                 root->fs_info->first_logical_byte = (u64)-1;
9692         spin_unlock(&root->fs_info->block_group_cache_lock);
9693
9694         down_write(&block_group->space_info->groups_sem);
9695         /*
9696          * we must use list_del_init so people can check to see if they
9697          * are still on the list after taking the semaphore
9698          */
9699         list_del_init(&block_group->list);
9700         if (list_empty(&block_group->space_info->block_groups[index])) {
9701                 kobj = block_group->space_info->block_group_kobjs[index];
9702                 block_group->space_info->block_group_kobjs[index] = NULL;
9703                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9704         }
9705         up_write(&block_group->space_info->groups_sem);
9706         if (kobj) {
9707                 kobject_del(kobj);
9708                 kobject_put(kobj);
9709         }
9710
9711         if (block_group->has_caching_ctl)
9712                 caching_ctl = get_caching_control(block_group);
9713         if (block_group->cached == BTRFS_CACHE_STARTED)
9714                 wait_block_group_cache_done(block_group);
9715         if (block_group->has_caching_ctl) {
9716                 down_write(&root->fs_info->commit_root_sem);
9717                 if (!caching_ctl) {
9718                         struct btrfs_caching_control *ctl;
9719
9720                         list_for_each_entry(ctl,
9721                                     &root->fs_info->caching_block_groups, list)
9722                                 if (ctl->block_group == block_group) {
9723                                         caching_ctl = ctl;
9724                                         atomic_inc(&caching_ctl->count);
9725                                         break;
9726                                 }
9727                 }
9728                 if (caching_ctl)
9729                         list_del_init(&caching_ctl->list);
9730                 up_write(&root->fs_info->commit_root_sem);
9731                 if (caching_ctl) {
9732                         /* Once for the caching bgs list and once for us. */
9733                         put_caching_control(caching_ctl);
9734                         put_caching_control(caching_ctl);
9735                 }
9736         }
9737
9738         spin_lock(&trans->transaction->dirty_bgs_lock);
9739         if (!list_empty(&block_group->dirty_list)) {
9740                 WARN_ON(1);
9741         }
9742         if (!list_empty(&block_group->io_list)) {
9743                 WARN_ON(1);
9744         }
9745         spin_unlock(&trans->transaction->dirty_bgs_lock);
9746         btrfs_remove_free_space_cache(block_group);
9747
9748         spin_lock(&block_group->space_info->lock);
9749         list_del_init(&block_group->ro_list);
9750
9751         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
9752                 WARN_ON(block_group->space_info->total_bytes
9753                         < block_group->key.offset);
9754                 WARN_ON(block_group->space_info->bytes_readonly
9755                         < block_group->key.offset);
9756                 WARN_ON(block_group->space_info->disk_total
9757                         < block_group->key.offset * factor);
9758         }
9759         block_group->space_info->total_bytes -= block_group->key.offset;
9760         block_group->space_info->bytes_readonly -= block_group->key.offset;
9761         block_group->space_info->disk_total -= block_group->key.offset * factor;
9762
9763         spin_unlock(&block_group->space_info->lock);
9764
9765         memcpy(&key, &block_group->key, sizeof(key));
9766
9767         lock_chunks(root);
9768         if (!list_empty(&em->list)) {
9769                 /* We're in the transaction->pending_chunks list. */
9770                 free_extent_map(em);
9771         }
9772         spin_lock(&block_group->lock);
9773         block_group->removed = 1;
9774         /*
9775          * At this point trimming can't start on this block group, because we
9776          * removed the block group from the tree fs_info->block_group_cache_tree
9777          * so no one can't find it anymore and even if someone already got this
9778          * block group before we removed it from the rbtree, they have already
9779          * incremented block_group->trimming - if they didn't, they won't find
9780          * any free space entries because we already removed them all when we
9781          * called btrfs_remove_free_space_cache().
9782          *
9783          * And we must not remove the extent map from the fs_info->mapping_tree
9784          * to prevent the same logical address range and physical device space
9785          * ranges from being reused for a new block group. This is because our
9786          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
9787          * completely transactionless, so while it is trimming a range the
9788          * currently running transaction might finish and a new one start,
9789          * allowing for new block groups to be created that can reuse the same
9790          * physical device locations unless we take this special care.
9791          */
9792         remove_em = (atomic_read(&block_group->trimming) == 0);
9793         /*
9794          * Make sure a trimmer task always sees the em in the pinned_chunks list
9795          * if it sees block_group->removed == 1 (needs to lock block_group->lock
9796          * before checking block_group->removed).
9797          */
9798         if (!remove_em) {
9799                 /*
9800                  * Our em might be in trans->transaction->pending_chunks which
9801                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
9802                  * and so is the fs_info->pinned_chunks list.
9803                  *
9804                  * So at this point we must be holding the chunk_mutex to avoid
9805                  * any races with chunk allocation (more specifically at
9806                  * volumes.c:contains_pending_extent()), to ensure it always
9807                  * sees the em, either in the pending_chunks list or in the
9808                  * pinned_chunks list.
9809                  */
9810                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
9811         }
9812         spin_unlock(&block_group->lock);
9813
9814         if (remove_em) {
9815                 struct extent_map_tree *em_tree;
9816
9817                 em_tree = &root->fs_info->mapping_tree.map_tree;
9818                 write_lock(&em_tree->lock);
9819                 /*
9820                  * The em might be in the pending_chunks list, so make sure the
9821                  * chunk mutex is locked, since remove_extent_mapping() will
9822                  * delete us from that list.
9823                  */
9824                 remove_extent_mapping(em_tree, em);
9825                 write_unlock(&em_tree->lock);
9826                 /* once for the tree */
9827                 free_extent_map(em);
9828         }
9829
9830         unlock_chunks(root);
9831
9832         btrfs_put_block_group(block_group);
9833         btrfs_put_block_group(block_group);
9834
9835         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
9836         if (ret > 0)
9837                 ret = -EIO;
9838         if (ret < 0)
9839                 goto out;
9840
9841         ret = btrfs_del_item(trans, root, path);
9842 out:
9843         btrfs_free_path(path);
9844         return ret;
9845 }
9846
9847 /*
9848  * Process the unused_bgs list and remove any that don't have any allocated
9849  * space inside of them.
9850  */
9851 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
9852 {
9853         struct btrfs_block_group_cache *block_group;
9854         struct btrfs_space_info *space_info;
9855         struct btrfs_root *root = fs_info->extent_root;
9856         struct btrfs_trans_handle *trans;
9857         int ret = 0;
9858
9859         if (!fs_info->open)
9860                 return;
9861
9862         spin_lock(&fs_info->unused_bgs_lock);
9863         while (!list_empty(&fs_info->unused_bgs)) {
9864                 u64 start, end;
9865
9866                 block_group = list_first_entry(&fs_info->unused_bgs,
9867                                                struct btrfs_block_group_cache,
9868                                                bg_list);
9869                 space_info = block_group->space_info;
9870                 list_del_init(&block_group->bg_list);
9871                 if (ret || btrfs_mixed_space_info(space_info)) {
9872                         btrfs_put_block_group(block_group);
9873                         continue;
9874                 }
9875                 spin_unlock(&fs_info->unused_bgs_lock);
9876
9877                 /* Don't want to race with allocators so take the groups_sem */
9878                 down_write(&space_info->groups_sem);
9879                 spin_lock(&block_group->lock);
9880                 if (block_group->reserved ||
9881                     btrfs_block_group_used(&block_group->item) ||
9882                     block_group->ro) {
9883                         /*
9884                          * We want to bail if we made new allocations or have
9885                          * outstanding allocations in this block group.  We do
9886                          * the ro check in case balance is currently acting on
9887                          * this block group.
9888                          */
9889                         spin_unlock(&block_group->lock);
9890                         up_write(&space_info->groups_sem);
9891                         goto next;
9892                 }
9893                 spin_unlock(&block_group->lock);
9894
9895                 /* We don't want to force the issue, only flip if it's ok. */
9896                 ret = set_block_group_ro(block_group, 0);
9897                 up_write(&space_info->groups_sem);
9898                 if (ret < 0) {
9899                         ret = 0;
9900                         goto next;
9901                 }
9902
9903                 /*
9904                  * Want to do this before we do anything else so we can recover
9905                  * properly if we fail to join the transaction.
9906                  */
9907                 /* 1 for btrfs_orphan_reserve_metadata() */
9908                 trans = btrfs_start_transaction(root, 1);
9909                 if (IS_ERR(trans)) {
9910                         btrfs_set_block_group_rw(root, block_group);
9911                         ret = PTR_ERR(trans);
9912                         goto next;
9913                 }
9914
9915                 /*
9916                  * We could have pending pinned extents for this block group,
9917                  * just delete them, we don't care about them anymore.
9918                  */
9919                 start = block_group->key.objectid;
9920                 end = start + block_group->key.offset - 1;
9921                 /*
9922                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
9923                  * btrfs_finish_extent_commit(). If we are at transaction N,
9924                  * another task might be running finish_extent_commit() for the
9925                  * previous transaction N - 1, and have seen a range belonging
9926                  * to the block group in freed_extents[] before we were able to
9927                  * clear the whole block group range from freed_extents[]. This
9928                  * means that task can lookup for the block group after we
9929                  * unpinned it from freed_extents[] and removed it, leading to
9930                  * a BUG_ON() at btrfs_unpin_extent_range().
9931                  */
9932                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
9933                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
9934                                   EXTENT_DIRTY, GFP_NOFS);
9935                 if (ret) {
9936                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9937                         btrfs_set_block_group_rw(root, block_group);
9938                         goto end_trans;
9939                 }
9940                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
9941                                   EXTENT_DIRTY, GFP_NOFS);
9942                 if (ret) {
9943                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9944                         btrfs_set_block_group_rw(root, block_group);
9945                         goto end_trans;
9946                 }
9947                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9948
9949                 /* Reset pinned so btrfs_put_block_group doesn't complain */
9950                 spin_lock(&space_info->lock);
9951                 spin_lock(&block_group->lock);
9952
9953                 space_info->bytes_pinned -= block_group->pinned;
9954                 space_info->bytes_readonly += block_group->pinned;
9955                 percpu_counter_add(&space_info->total_bytes_pinned,
9956                                    -block_group->pinned);
9957                 block_group->pinned = 0;
9958
9959                 spin_unlock(&block_group->lock);
9960                 spin_unlock(&space_info->lock);
9961
9962                 /*
9963                  * Btrfs_remove_chunk will abort the transaction if things go
9964                  * horribly wrong.
9965                  */
9966                 ret = btrfs_remove_chunk(trans, root,
9967                                          block_group->key.objectid);
9968 end_trans:
9969                 btrfs_end_transaction(trans, root);
9970 next:
9971                 btrfs_put_block_group(block_group);
9972                 spin_lock(&fs_info->unused_bgs_lock);
9973         }
9974         spin_unlock(&fs_info->unused_bgs_lock);
9975 }
9976
9977 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
9978 {
9979         struct btrfs_space_info *space_info;
9980         struct btrfs_super_block *disk_super;
9981         u64 features;
9982         u64 flags;
9983         int mixed = 0;
9984         int ret;
9985
9986         disk_super = fs_info->super_copy;
9987         if (!btrfs_super_root(disk_super))
9988                 return 1;
9989
9990         features = btrfs_super_incompat_flags(disk_super);
9991         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
9992                 mixed = 1;
9993
9994         flags = BTRFS_BLOCK_GROUP_SYSTEM;
9995         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9996         if (ret)
9997                 goto out;
9998
9999         if (mixed) {
10000                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10001                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10002         } else {
10003                 flags = BTRFS_BLOCK_GROUP_METADATA;
10004                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10005                 if (ret)
10006                         goto out;
10007
10008                 flags = BTRFS_BLOCK_GROUP_DATA;
10009                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10010         }
10011 out:
10012         return ret;
10013 }
10014
10015 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10016 {
10017         return unpin_extent_range(root, start, end, false);
10018 }
10019
10020 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10021 {
10022         struct btrfs_fs_info *fs_info = root->fs_info;
10023         struct btrfs_block_group_cache *cache = NULL;
10024         u64 group_trimmed;
10025         u64 start;
10026         u64 end;
10027         u64 trimmed = 0;
10028         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10029         int ret = 0;
10030
10031         /*
10032          * try to trim all FS space, our block group may start from non-zero.
10033          */
10034         if (range->len == total_bytes)
10035                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10036         else
10037                 cache = btrfs_lookup_block_group(fs_info, range->start);
10038
10039         while (cache) {
10040                 if (cache->key.objectid >= (range->start + range->len)) {
10041                         btrfs_put_block_group(cache);
10042                         break;
10043                 }
10044
10045                 start = max(range->start, cache->key.objectid);
10046                 end = min(range->start + range->len,
10047                                 cache->key.objectid + cache->key.offset);
10048
10049                 if (end - start >= range->minlen) {
10050                         if (!block_group_cache_done(cache)) {
10051                                 ret = cache_block_group(cache, 0);
10052                                 if (ret) {
10053                                         btrfs_put_block_group(cache);
10054                                         break;
10055                                 }
10056                                 ret = wait_block_group_cache_done(cache);
10057                                 if (ret) {
10058                                         btrfs_put_block_group(cache);
10059                                         break;
10060                                 }
10061                         }
10062                         ret = btrfs_trim_block_group(cache,
10063                                                      &group_trimmed,
10064                                                      start,
10065                                                      end,
10066                                                      range->minlen);
10067
10068                         trimmed += group_trimmed;
10069                         if (ret) {
10070                                 btrfs_put_block_group(cache);
10071                                 break;
10072                         }
10073                 }
10074
10075                 cache = next_block_group(fs_info->tree_root, cache);
10076         }
10077
10078         range->len = trimmed;
10079         return ret;
10080 }
10081
10082 /*
10083  * btrfs_{start,end}_write_no_snapshoting() are similar to
10084  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10085  * data into the page cache through nocow before the subvolume is snapshoted,
10086  * but flush the data into disk after the snapshot creation, or to prevent
10087  * operations while snapshoting is ongoing and that cause the snapshot to be
10088  * inconsistent (writes followed by expanding truncates for example).
10089  */
10090 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10091 {
10092         percpu_counter_dec(&root->subv_writers->counter);
10093         /*
10094          * Make sure counter is updated before we wake up
10095          * waiters.
10096          */
10097         smp_mb();
10098         if (waitqueue_active(&root->subv_writers->wait))
10099                 wake_up(&root->subv_writers->wait);
10100 }
10101
10102 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10103 {
10104         if (atomic_read(&root->will_be_snapshoted))
10105                 return 0;
10106
10107         percpu_counter_inc(&root->subv_writers->counter);
10108         /*
10109          * Make sure counter is updated before we check for snapshot creation.
10110          */
10111         smp_mb();
10112         if (atomic_read(&root->will_be_snapshoted)) {
10113                 btrfs_end_write_no_snapshoting(root);
10114                 return 0;
10115         }
10116         return 1;
10117 }