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 "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "math.h"
  38 #include "sysfs.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_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op);
  85 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  86                                     struct extent_buffer *leaf,
  87                                     struct btrfs_extent_item *ei);
  88 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  89                                       struct btrfs_root *root,
  90                                       u64 parent, u64 root_objectid,
  91                                       u64 flags, u64 owner, u64 offset,
  92                                       struct btrfs_key *ins, int ref_mod);
  93 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  94                                      struct btrfs_root *root,
  95                                      u64 parent, u64 root_objectid,
  96                                      u64 flags, struct btrfs_disk_key *key,
  97                                      int level, struct btrfs_key *ins);
  98 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  99                           struct btrfs_root *extent_root, u64 flags,
 100                           int force);
 101 static int find_next_key(struct btrfs_path *path, int level,
 102                          struct btrfs_key *key);
 103 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 104                             int dump_block_groups);
 105 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 106                                        u64 num_bytes, int reserve);
 107 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 108                                u64 num_bytes);
 109 int btrfs_pin_extent(struct btrfs_root *root,
 110                      u64 bytenr, u64 num_bytes, int reserved);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135                 kfree(cache->free_space_ctl);
 136                 kfree(cache);
 137         }
 138 }
 139
 140 /*
 141  * this adds the block group to the fs_info rb tree for the block group
 142  * cache
 143  */
 144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 145                                 struct btrfs_block_group_cache *block_group)
 146 {
 147         struct rb_node **p;
 148         struct rb_node *parent = NULL;
 149         struct btrfs_block_group_cache *cache;
 150
 151         spin_lock(&info->block_group_cache_lock);
 152         p = &info->block_group_cache_tree.rb_node;
 153
 154         while (*p) {
 155                 parent = *p;
 156                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 157                                  cache_node);
 158                 if (block_group->key.objectid < cache->key.objectid) {
 159                         p = &(*p)->rb_left;
 160                 } else if (block_group->key.objectid > cache->key.objectid) {
 161                         p = &(*p)->rb_right;
 162                 } else {
 163                         spin_unlock(&info->block_group_cache_lock);
 164                         return -EEXIST;
 165                 }
 166         }
 167
 168         rb_link_node(&block_group->cache_node, parent, p);
 169         rb_insert_color(&block_group->cache_node,
 170                         &info->block_group_cache_tree);
 171
 172         if (info->first_logical_byte > block_group->key.objectid)
 173                 info->first_logical_byte = block_group->key.objectid;
 174
 175         spin_unlock(&info->block_group_cache_lock);
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * This will return the block group at or after bytenr if contains is 0, else
 182  * it will return the block group that contains the bytenr
 183  */
 184 static struct btrfs_block_group_cache *
 185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 186                               int contains)
 187 {
 188         struct btrfs_block_group_cache *cache, *ret = NULL;
 189         struct rb_node *n;
 190         u64 end, start;
 191
 192         spin_lock(&info->block_group_cache_lock);
 193         n = info->block_group_cache_tree.rb_node;
 194
 195         while (n) {
 196                 cache = rb_entry(n, struct btrfs_block_group_cache,
 197                                  cache_node);
 198                 end = cache->key.objectid + cache->key.offset - 1;
 199                 start = cache->key.objectid;
 200
 201                 if (bytenr < start) {
 202                         if (!contains && (!ret || start < ret->key.objectid))
 203                                 ret = cache;
 204                         n = n->rb_left;
 205                 } else if (bytenr > start) {
 206                         if (contains && bytenr <= end) {
 207                                 ret = cache;
 208                                 break;
 209                         }
 210                         n = n->rb_right;
 211                 } else {
 212                         ret = cache;
 213                         break;
 214                 }
 215         }
 216         if (ret) {
 217                 btrfs_get_block_group(ret);
 218                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 219                         info->first_logical_byte = ret->key.objectid;
 220         }
 221         spin_unlock(&info->block_group_cache_lock);
 222
 223         return ret;
 224 }
 225
 226 static int add_excluded_extent(struct btrfs_root *root,
 227                                u64 start, u64 num_bytes)
 228 {
 229         u64 end = start + num_bytes - 1;
 230         set_extent_bits(&root->fs_info->freed_extents[0],
 231                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 232         set_extent_bits(&root->fs_info->freed_extents[1],
 233                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 234         return 0;
 235 }
 236
 237 static void free_excluded_extents(struct btrfs_root *root,
 238                                   struct btrfs_block_group_cache *cache)
 239 {
 240         u64 start, end;
 241
 242         start = cache->key.objectid;
 243         end = start + cache->key.offset - 1;
 244
 245         clear_extent_bits(&root->fs_info->freed_extents[0],
 246                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 247         clear_extent_bits(&root->fs_info->freed_extents[1],
 248                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 249 }
 250
 251 static int exclude_super_stripes(struct btrfs_root *root,
 252                                  struct btrfs_block_group_cache *cache)
 253 {
 254         u64 bytenr;
 255         u64 *logical;
 256         int stripe_len;
 257         int i, nr, ret;
 258
 259         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 260                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 261                 cache->bytes_super += stripe_len;
 262                 ret = add_excluded_extent(root, cache->key.objectid,
 263                                           stripe_len);
 264                 if (ret)
 265                         return ret;
 266         }
 267
 268         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 269                 bytenr = btrfs_sb_offset(i);
 270                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 271                                        cache->key.objectid, bytenr,
 272                                        0, &logical, &nr, &stripe_len);
 273                 if (ret)
 274                         return ret;
 275
 276                 while (nr--) {
 277                         u64 start, len;
 278
 279                         if (logical[nr] > cache->key.objectid +
 280                             cache->key.offset)
 281                                 continue;
 282
 283                         if (logical[nr] + stripe_len <= cache->key.objectid)
 284                                 continue;
 285
 286                         start = logical[nr];
 287                         if (start < cache->key.objectid) {
 288                                 start = cache->key.objectid;
 289                                 len = (logical[nr] + stripe_len) - start;
 290                         } else {
 291                                 len = min_t(u64, stripe_len,
 292                                             cache->key.objectid +
 293                                             cache->key.offset - start);
 294                         }
 295
 296                         cache->bytes_super += len;
 297                         ret = add_excluded_extent(root, start, len);
 298                         if (ret) {
 299                                 kfree(logical);
 300                                 return ret;
 301                         }
 302                 }
 303
 304                 kfree(logical);
 305         }
 306         return 0;
 307 }
 308
 309 static struct btrfs_caching_control *
 310 get_caching_control(struct btrfs_block_group_cache *cache)
 311 {
 312         struct btrfs_caching_control *ctl;
 313
 314         spin_lock(&cache->lock);
 315         if (cache->cached != BTRFS_CACHE_STARTED) {
 316                 spin_unlock(&cache->lock);
 317                 return NULL;
 318         }
 319
 320         /* We're loading it the fast way, so we don't have a caching_ctl. */
 321         if (!cache->caching_ctl) {
 322                 spin_unlock(&cache->lock);
 323                 return NULL;
 324         }
 325
 326         ctl = cache->caching_ctl;
 327         atomic_inc(&ctl->count);
 328         spin_unlock(&cache->lock);
 329         return ctl;
 330 }
 331
 332 static void put_caching_control(struct btrfs_caching_control *ctl)
 333 {
 334         if (atomic_dec_and_test(&ctl->count))
 335                 kfree(ctl);
 336 }
 337
 338 /*
 339  * this is only called by cache_block_group, since we could have freed extents
 340  * we need to check the pinned_extents for any extents that can't be used yet
 341  * since their free space will be released as soon as the transaction commits.
 342  */
 343 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 344                               struct btrfs_fs_info *info, u64 start, u64 end)
 345 {
 346         u64 extent_start, extent_end, size, total_added = 0;
 347         int ret;
 348
 349         while (start < end) {
 350                 ret = find_first_extent_bit(info->pinned_extents, start,
 351                                             &extent_start, &extent_end,
 352                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 353                                             NULL);
 354                 if (ret)
 355                         break;
 356
 357                 if (extent_start <= start) {
 358                         start = extent_end + 1;
 359                 } else if (extent_start > start && extent_start < end) {
 360                         size = extent_start - start;
 361                         total_added += size;
 362                         ret = btrfs_add_free_space(block_group, start,
 363                                                    size);
 364                         BUG_ON(ret); /* -ENOMEM or logic error */
 365                         start = extent_end + 1;
 366                 } else {
 367                         break;
 368                 }
 369         }
 370
 371         if (start < end) {
 372                 size = end - start;
 373                 total_added += size;
 374                 ret = btrfs_add_free_space(block_group, start, size);
 375                 BUG_ON(ret); /* -ENOMEM or logic error */
 376         }
 377
 378         return total_added;
 379 }
 380
 381 static noinline void caching_thread(struct btrfs_work *work)
 382 {
 383         struct btrfs_block_group_cache *block_group;
 384         struct btrfs_fs_info *fs_info;
 385         struct btrfs_caching_control *caching_ctl;
 386         struct btrfs_root *extent_root;
 387         struct btrfs_path *path;
 388         struct extent_buffer *leaf;
 389         struct btrfs_key key;
 390         u64 total_found = 0;
 391         u64 last = 0;
 392         u32 nritems;
 393         int ret = -ENOMEM;
 394
 395         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 396         block_group = caching_ctl->block_group;
 397         fs_info = block_group->fs_info;
 398         extent_root = fs_info->extent_root;
 399
 400         path = btrfs_alloc_path();
 401         if (!path)
 402                 goto out;
 403
 404         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 405
 406         /*
 407          * We don't want to deadlock with somebody trying to allocate a new
 408          * extent for the extent root while also trying to search the extent
 409          * root to add free space.  So we skip locking and search the commit
 410          * root, since its read-only
 411          */
 412         path->skip_locking = 1;
 413         path->search_commit_root = 1;
 414         path->reada = 1;
 415
 416         key.objectid = last;
 417         key.offset = 0;
 418         key.type = BTRFS_EXTENT_ITEM_KEY;
 419 again:
 420         mutex_lock(&caching_ctl->mutex);
 421         /* need to make sure the commit_root doesn't disappear */
 422         down_read(&fs_info->extent_commit_sem);
 423
 424 next:
 425         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 426         if (ret < 0)
 427                 goto err;
 428
 429         leaf = path->nodes[0];
 430         nritems = btrfs_header_nritems(leaf);
 431
 432         while (1) {
 433                 if (btrfs_fs_closing(fs_info) > 1) {
 434                         last = (u64)-1;
 435                         break;
 436                 }
 437
 438                 if (path->slots[0] < nritems) {
 439                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 440                 } else {
 441                         ret = find_next_key(path, 0, &key);
 442                         if (ret)
 443                                 break;
 444
 445                         if (need_resched() ||
 446                             rwsem_is_contended(&fs_info->extent_commit_sem)) {
 447                                 caching_ctl->progress = last;
 448                                 btrfs_release_path(path);
 449                                 up_read(&fs_info->extent_commit_sem);
 450                                 mutex_unlock(&caching_ctl->mutex);
 451                                 cond_resched();
 452                                 goto again;
 453                         }
 454
 455                         ret = btrfs_next_leaf(extent_root, path);
 456                         if (ret < 0)
 457                                 goto err;
 458                         if (ret)
 459                                 break;
 460                         leaf = path->nodes[0];
 461                         nritems = btrfs_header_nritems(leaf);
 462                         continue;
 463                 }
 464
 465                 if (key.objectid < last) {
 466                         key.objectid = last;
 467                         key.offset = 0;
 468                         key.type = BTRFS_EXTENT_ITEM_KEY;
 469
 470                         caching_ctl->progress = last;
 471                         btrfs_release_path(path);
 472                         goto next;
 473                 }
 474
 475                 if (key.objectid < block_group->key.objectid) {
 476                         path->slots[0]++;
 477                         continue;
 478                 }
 479
 480                 if (key.objectid >= block_group->key.objectid +
 481                     block_group->key.offset)
 482                         break;
 483
 484                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 485                     key.type == BTRFS_METADATA_ITEM_KEY) {
 486                         total_found += add_new_free_space(block_group,
 487                                                           fs_info, last,
 488                                                           key.objectid);
 489                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 490                                 last = key.objectid +
 491                                         fs_info->tree_root->leafsize;
 492                         else
 493                                 last = key.objectid + key.offset;
 494
 495                         if (total_found > (1024 * 1024 * 2)) {
 496                                 total_found = 0;
 497                                 wake_up(&caching_ctl->wait);
 498                         }
 499                 }
 500                 path->slots[0]++;
 501         }
 502         ret = 0;
 503
 504         total_found += add_new_free_space(block_group, fs_info, last,
 505                                           block_group->key.objectid +
 506                                           block_group->key.offset);
 507         caching_ctl->progress = (u64)-1;
 508
 509         spin_lock(&block_group->lock);
 510         block_group->caching_ctl = NULL;
 511         block_group->cached = BTRFS_CACHE_FINISHED;
 512         spin_unlock(&block_group->lock);
 513
 514 err:
 515         btrfs_free_path(path);
 516         up_read(&fs_info->extent_commit_sem);
 517
 518         free_excluded_extents(extent_root, block_group);
 519
 520         mutex_unlock(&caching_ctl->mutex);
 521 out:
 522         if (ret) {
 523                 spin_lock(&block_group->lock);
 524                 block_group->caching_ctl = NULL;
 525                 block_group->cached = BTRFS_CACHE_ERROR;
 526                 spin_unlock(&block_group->lock);
 527         }
 528         wake_up(&caching_ctl->wait);
 529
 530         put_caching_control(caching_ctl);
 531         btrfs_put_block_group(block_group);
 532 }
 533
 534 static int cache_block_group(struct btrfs_block_group_cache *cache,
 535                              int load_cache_only)
 536 {
 537         DEFINE_WAIT(wait);
 538         struct btrfs_fs_info *fs_info = cache->fs_info;
 539         struct btrfs_caching_control *caching_ctl;
 540         int ret = 0;
 541
 542         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 543         if (!caching_ctl)
 544                 return -ENOMEM;
 545
 546         INIT_LIST_HEAD(&caching_ctl->list);
 547         mutex_init(&caching_ctl->mutex);
 548         init_waitqueue_head(&caching_ctl->wait);
 549         caching_ctl->block_group = cache;
 550         caching_ctl->progress = cache->key.objectid;
 551         atomic_set(&caching_ctl->count, 1);
 552         caching_ctl->work.func = caching_thread;
 553
 554         spin_lock(&cache->lock);
 555         /*
 556          * This should be a rare occasion, but this could happen I think in the
 557          * case where one thread starts to load the space cache info, and then
 558          * some other thread starts a transaction commit which tries to do an
 559          * allocation while the other thread is still loading the space cache
 560          * info.  The previous loop should have kept us from choosing this block
 561          * group, but if we've moved to the state where we will wait on caching
 562          * block groups we need to first check if we're doing a fast load here,
 563          * so we can wait for it to finish, otherwise we could end up allocating
 564          * from a block group who's cache gets evicted for one reason or
 565          * another.
 566          */
 567         while (cache->cached == BTRFS_CACHE_FAST) {
 568                 struct btrfs_caching_control *ctl;
 569
 570                 ctl = cache->caching_ctl;
 571                 atomic_inc(&ctl->count);
 572                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 573                 spin_unlock(&cache->lock);
 574
 575                 schedule();
 576
 577                 finish_wait(&ctl->wait, &wait);
 578                 put_caching_control(ctl);
 579                 spin_lock(&cache->lock);
 580         }
 581
 582         if (cache->cached != BTRFS_CACHE_NO) {
 583                 spin_unlock(&cache->lock);
 584                 kfree(caching_ctl);
 585                 return 0;
 586         }
 587         WARN_ON(cache->caching_ctl);
 588         cache->caching_ctl = caching_ctl;
 589         cache->cached = BTRFS_CACHE_FAST;
 590         spin_unlock(&cache->lock);
 591
 592         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 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                 } else {
 601                         if (load_cache_only) {
 602                                 cache->caching_ctl = NULL;
 603                                 cache->cached = BTRFS_CACHE_NO;
 604                         } else {
 605                                 cache->cached = BTRFS_CACHE_STARTED;
 606                         }
 607                 }
 608                 spin_unlock(&cache->lock);
 609                 wake_up(&caching_ctl->wait);
 610                 if (ret == 1) {
 611                         put_caching_control(caching_ctl);
 612                         free_excluded_extents(fs_info->extent_root, cache);
 613                         return 0;
 614                 }
 615         } else {
 616                 /*
 617                  * We are not going to do the fast caching, set cached to the
 618                  * appropriate value and wakeup any waiters.
 619                  */
 620                 spin_lock(&cache->lock);
 621                 if (load_cache_only) {
 622                         cache->caching_ctl = NULL;
 623                         cache->cached = BTRFS_CACHE_NO;
 624                 } else {
 625                         cache->cached = BTRFS_CACHE_STARTED;
 626                 }
 627                 spin_unlock(&cache->lock);
 628                 wake_up(&caching_ctl->wait);
 629         }
 630
 631         if (load_cache_only) {
 632                 put_caching_control(caching_ctl);
 633                 return 0;
 634         }
 635
 636         down_write(&fs_info->extent_commit_sem);
 637         atomic_inc(&caching_ctl->count);
 638         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 639         up_write(&fs_info->extent_commit_sem);
 640
 641         btrfs_get_block_group(cache);
 642
 643         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 644
 645         return ret;
 646 }
 647
 648 /*
 649  * return the block group that starts at or after bytenr
 650  */
 651 static struct btrfs_block_group_cache *
 652 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 653 {
 654         struct btrfs_block_group_cache *cache;
 655
 656         cache = block_group_cache_tree_search(info, bytenr, 0);
 657
 658         return cache;
 659 }
 660
 661 /*
 662  * return the block group that contains the given bytenr
 663  */
 664 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 665                                                  struct btrfs_fs_info *info,
 666                                                  u64 bytenr)
 667 {
 668         struct btrfs_block_group_cache *cache;
 669
 670         cache = block_group_cache_tree_search(info, bytenr, 1);
 671
 672         return cache;
 673 }
 674
 675 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 676                                                   u64 flags)
 677 {
 678         struct list_head *head = &info->space_info;
 679         struct btrfs_space_info *found;
 680
 681         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 682
 683         rcu_read_lock();
 684         list_for_each_entry_rcu(found, head, list) {
 685                 if (found->flags & flags) {
 686                         rcu_read_unlock();
 687                         return found;
 688                 }
 689         }
 690         rcu_read_unlock();
 691         return NULL;
 692 }
 693
 694 /*
 695  * after adding space to the filesystem, we need to clear the full flags
 696  * on all the space infos.
 697  */
 698 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 699 {
 700         struct list_head *head = &info->space_info;
 701         struct btrfs_space_info *found;
 702
 703         rcu_read_lock();
 704         list_for_each_entry_rcu(found, head, list)
 705                 found->full = 0;
 706         rcu_read_unlock();
 707 }
 708
 709 /* simple helper to search for an existing extent at a given offset */
 710 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 711 {
 712         int ret;
 713         struct btrfs_key key;
 714         struct btrfs_path *path;
 715
 716         path = btrfs_alloc_path();
 717         if (!path)
 718                 return -ENOMEM;
 719
 720         key.objectid = start;
 721         key.offset = len;
 722         key.type = BTRFS_EXTENT_ITEM_KEY;
 723         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 724                                 0, 0);
 725         if (ret > 0) {
 726                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 727                 if (key.objectid == start &&
 728                     key.type == BTRFS_METADATA_ITEM_KEY)
 729                         ret = 0;
 730         }
 731         btrfs_free_path(path);
 732         return ret;
 733 }
 734
 735 /*
 736  * helper function to lookup reference count and flags of a tree block.
 737  *
 738  * the head node for delayed ref is used to store the sum of all the
 739  * reference count modifications queued up in the rbtree. the head
 740  * node may also store the extent flags to set. This way you can check
 741  * to see what the reference count and extent flags would be if all of
 742  * the delayed refs are not processed.
 743  */
 744 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 745                              struct btrfs_root *root, u64 bytenr,
 746                              u64 offset, int metadata, u64 *refs, u64 *flags)
 747 {
 748         struct btrfs_delayed_ref_head *head;
 749         struct btrfs_delayed_ref_root *delayed_refs;
 750         struct btrfs_path *path;
 751         struct btrfs_extent_item *ei;
 752         struct extent_buffer *leaf;
 753         struct btrfs_key key;
 754         u32 item_size;
 755         u64 num_refs;
 756         u64 extent_flags;
 757         int ret;
 758
 759         /*
 760          * If we don't have skinny metadata, don't bother doing anything
 761          * different
 762          */
 763         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 764                 offset = root->leafsize;
 765                 metadata = 0;
 766         }
 767
 768         path = btrfs_alloc_path();
 769         if (!path)
 770                 return -ENOMEM;
 771
 772         if (!trans) {
 773                 path->skip_locking = 1;
 774                 path->search_commit_root = 1;
 775         }
 776
 777 search_again:
 778         key.objectid = bytenr;
 779         key.offset = offset;
 780         if (metadata)
 781                 key.type = BTRFS_METADATA_ITEM_KEY;
 782         else
 783                 key.type = BTRFS_EXTENT_ITEM_KEY;
 784
 785 again:
 786         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 787                                 &key, path, 0, 0);
 788         if (ret < 0)
 789                 goto out_free;
 790
 791         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 792                 if (path->slots[0]) {
 793                         path->slots[0]--;
 794                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 795                                               path->slots[0]);
 796                         if (key.objectid == bytenr &&
 797                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 798                             key.offset == root->leafsize)
 799                                 ret = 0;
 800                 }
 801                 if (ret) {
 802                         key.objectid = bytenr;
 803                         key.type = BTRFS_EXTENT_ITEM_KEY;
 804                         key.offset = root->leafsize;
 805                         btrfs_release_path(path);
 806                         goto again;
 807                 }
 808         }
 809
 810         if (ret == 0) {
 811                 leaf = path->nodes[0];
 812                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 813                 if (item_size >= sizeof(*ei)) {
 814                         ei = btrfs_item_ptr(leaf, path->slots[0],
 815                                             struct btrfs_extent_item);
 816                         num_refs = btrfs_extent_refs(leaf, ei);
 817                         extent_flags = btrfs_extent_flags(leaf, ei);
 818                 } else {
 819 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 820                         struct btrfs_extent_item_v0 *ei0;
 821                         BUG_ON(item_size != sizeof(*ei0));
 822                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 823                                              struct btrfs_extent_item_v0);
 824                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 825                         /* FIXME: this isn't correct for data */
 826                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 827 #else
 828                         BUG();
 829 #endif
 830                 }
 831                 BUG_ON(num_refs == 0);
 832         } else {
 833                 num_refs = 0;
 834                 extent_flags = 0;
 835                 ret = 0;
 836         }
 837
 838         if (!trans)
 839                 goto out;
 840
 841         delayed_refs = &trans->transaction->delayed_refs;
 842         spin_lock(&delayed_refs->lock);
 843         head = btrfs_find_delayed_ref_head(trans, bytenr);
 844         if (head) {
 845                 if (!mutex_trylock(&head->mutex)) {
 846                         atomic_inc(&head->node.refs);
 847                         spin_unlock(&delayed_refs->lock);
 848
 849                         btrfs_release_path(path);
 850
 851                         /*
 852                          * Mutex was contended, block until it's released and try
 853                          * again
 854                          */
 855                         mutex_lock(&head->mutex);
 856                         mutex_unlock(&head->mutex);
 857                         btrfs_put_delayed_ref(&head->node);
 858                         goto search_again;
 859                 }
 860                 if (head->extent_op && head->extent_op->update_flags)
 861                         extent_flags |= head->extent_op->flags_to_set;
 862                 else
 863                         BUG_ON(num_refs == 0);
 864
 865                 num_refs += head->node.ref_mod;
 866                 mutex_unlock(&head->mutex);
 867         }
 868         spin_unlock(&delayed_refs->lock);
 869 out:
 870         WARN_ON(num_refs == 0);
 871         if (refs)
 872                 *refs = num_refs;
 873         if (flags)
 874                 *flags = extent_flags;
 875 out_free:
 876         btrfs_free_path(path);
 877         return ret;
 878 }
 879
 880 /*
 881  * Back reference rules.  Back refs have three main goals:
 882  *
 883  * 1) differentiate between all holders of references to an extent so that
 884  *    when a reference is dropped we can make sure it was a valid reference
 885  *    before freeing the extent.
 886  *
 887  * 2) Provide enough information to quickly find the holders of an extent
 888  *    if we notice a given block is corrupted or bad.
 889  *
 890  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 891  *    maintenance.  This is actually the same as #2, but with a slightly
 892  *    different use case.
 893  *
 894  * There are two kinds of back refs. The implicit back refs is optimized
 895  * for pointers in non-shared tree blocks. For a given pointer in a block,
 896  * back refs of this kind provide information about the block's owner tree
 897  * and the pointer's key. These information allow us to find the block by
 898  * b-tree searching. The full back refs is for pointers in tree blocks not
 899  * referenced by their owner trees. The location of tree block is recorded
 900  * in the back refs. Actually the full back refs is generic, and can be
 901  * used in all cases the implicit back refs is used. The major shortcoming
 902  * of the full back refs is its overhead. Every time a tree block gets
 903  * COWed, we have to update back refs entry for all pointers in it.
 904  *
 905  * For a newly allocated tree block, we use implicit back refs for
 906  * pointers in it. This means most tree related operations only involve
 907  * implicit back refs. For a tree block created in old transaction, the
 908  * only way to drop a reference to it is COW it. So we can detect the
 909  * event that tree block loses its owner tree's reference and do the
 910  * back refs conversion.
 911  *
 912  * When a tree block is COW'd through a tree, there are four cases:
 913  *
 914  * The reference count of the block is one and the tree is the block's
 915  * owner tree. Nothing to do in this case.
 916  *
 917  * The reference count of the block is one and the tree is not the
 918  * block's owner tree. In this case, full back refs is used for pointers
 919  * in the block. Remove these full back refs, add implicit back refs for
 920  * every pointers in the new block.
 921  *
 922  * The reference count of the block is greater than one and the tree is
 923  * the block's owner tree. In this case, implicit back refs is used for
 924  * pointers in the block. Add full back refs for every pointers in the
 925  * block, increase lower level extents' reference counts. The original
 926  * implicit back refs are entailed to the new block.
 927  *
 928  * The reference count of the block is greater than one and the tree is
 929  * not the block's owner tree. Add implicit back refs for every pointer in
 930  * the new block, increase lower level extents' reference count.
 931  *
 932  * Back Reference Key composing:
 933  *
 934  * The key objectid corresponds to the first byte in the extent,
 935  * The key type is used to differentiate between types of back refs.
 936  * There are different meanings of the key offset for different types
 937  * of back refs.
 938  *
 939  * File extents can be referenced by:
 940  *
 941  * - multiple snapshots, subvolumes, or different generations in one subvol
 942  * - different files inside a single subvolume
 943  * - different offsets inside a file (bookend extents in file.c)
 944  *
 945  * The extent ref structure for the implicit back refs has fields for:
 946  *
 947  * - Objectid of the subvolume root
 948  * - objectid of the file holding the reference
 949  * - original offset in the file
 950  * - how many bookend extents
 951  *
 952  * The key offset for the implicit back refs is hash of the first
 953  * three fields.
 954  *
 955  * The extent ref structure for the full back refs has field for:
 956  *
 957  * - number of pointers in the tree leaf
 958  *
 959  * The key offset for the implicit back refs is the first byte of
 960  * the tree leaf
 961  *
 962  * When a file extent is allocated, The implicit back refs is used.
 963  * the fields are filled in:
 964  *
 965  *     (root_key.objectid, inode objectid, offset in file, 1)
 966  *
 967  * When a file extent is removed file truncation, we find the
 968  * corresponding implicit back refs and check the following fields:
 969  *
 970  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 971  *
 972  * Btree extents can be referenced by:
 973  *
 974  * - Different subvolumes
 975  *
 976  * Both the implicit back refs and the full back refs for tree blocks
 977  * only consist of key. The key offset for the implicit back refs is
 978  * objectid of block's owner tree. The key offset for the full back refs
 979  * is the first byte of parent block.
 980  *
 981  * When implicit back refs is used, information about the lowest key and
 982  * level of the tree block are required. These information are stored in
 983  * tree block info structure.
 984  */
 985
 986 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 987 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 988                                   struct btrfs_root *root,
 989                                   struct btrfs_path *path,
 990                                   u64 owner, u32 extra_size)
 991 {
 992         struct btrfs_extent_item *item;
 993         struct btrfs_extent_item_v0 *ei0;
 994         struct btrfs_extent_ref_v0 *ref0;
 995         struct btrfs_tree_block_info *bi;
 996         struct extent_buffer *leaf;
 997         struct btrfs_key key;
 998         struct btrfs_key found_key;
 999         u32 new_size = sizeof(*item);
1000         u64 refs;
1001         int ret;
1002
1003         leaf = path->nodes[0];
1004         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1005
1006         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1007         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1008                              struct btrfs_extent_item_v0);
1009         refs = btrfs_extent_refs_v0(leaf, ei0);
1010
1011         if (owner == (u64)-1) {
1012                 while (1) {
1013                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1014                                 ret = btrfs_next_leaf(root, path);
1015                                 if (ret < 0)
1016                                         return ret;
1017                                 BUG_ON(ret > 0); /* Corruption */
1018                                 leaf = path->nodes[0];
1019                         }
1020                         btrfs_item_key_to_cpu(leaf, &found_key,
1021                                               path->slots[0]);
1022                         BUG_ON(key.objectid != found_key.objectid);
1023                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1024                                 path->slots[0]++;
1025                                 continue;
1026                         }
1027                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1028                                               struct btrfs_extent_ref_v0);
1029                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1030                         break;
1031                 }
1032         }
1033         btrfs_release_path(path);
1034
1035         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1036                 new_size += sizeof(*bi);
1037
1038         new_size -= sizeof(*ei0);
1039         ret = btrfs_search_slot(trans, root, &key, path,
1040                                 new_size + extra_size, 1);
1041         if (ret < 0)
1042                 return ret;
1043         BUG_ON(ret); /* Corruption */
1044
1045         btrfs_extend_item(root, path, new_size);
1046
1047         leaf = path->nodes[0];
1048         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1049         btrfs_set_extent_refs(leaf, item, refs);
1050         /* FIXME: get real generation */
1051         btrfs_set_extent_generation(leaf, item, 0);
1052         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1053                 btrfs_set_extent_flags(leaf, item,
1054                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1055                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1056                 bi = (struct btrfs_tree_block_info *)(item + 1);
1057                 /* FIXME: get first key of the block */
1058                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1059                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1060         } else {
1061                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1062         }
1063         btrfs_mark_buffer_dirty(leaf);
1064         return 0;
1065 }
1066 #endif
1067
1068 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1069 {
1070         u32 high_crc = ~(u32)0;
1071         u32 low_crc = ~(u32)0;
1072         __le64 lenum;
1073
1074         lenum = cpu_to_le64(root_objectid);
1075         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1076         lenum = cpu_to_le64(owner);
1077         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1078         lenum = cpu_to_le64(offset);
1079         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1080
1081         return ((u64)high_crc << 31) ^ (u64)low_crc;
1082 }
1083
1084 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1085                                      struct btrfs_extent_data_ref *ref)
1086 {
1087         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1088                                     btrfs_extent_data_ref_objectid(leaf, ref),
1089                                     btrfs_extent_data_ref_offset(leaf, ref));
1090 }
1091
1092 static int match_extent_data_ref(struct extent_buffer *leaf,
1093                                  struct btrfs_extent_data_ref *ref,
1094                                  u64 root_objectid, u64 owner, u64 offset)
1095 {
1096         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1097             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1098             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1099                 return 0;
1100         return 1;
1101 }
1102
1103 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1104                                            struct btrfs_root *root,
1105                                            struct btrfs_path *path,
1106                                            u64 bytenr, u64 parent,
1107                                            u64 root_objectid,
1108                                            u64 owner, u64 offset)
1109 {
1110         struct btrfs_key key;
1111         struct btrfs_extent_data_ref *ref;
1112         struct extent_buffer *leaf;
1113         u32 nritems;
1114         int ret;
1115         int recow;
1116         int err = -ENOENT;
1117
1118         key.objectid = bytenr;
1119         if (parent) {
1120                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1121                 key.offset = parent;
1122         } else {
1123                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1124                 key.offset = hash_extent_data_ref(root_objectid,
1125                                                   owner, offset);
1126         }
1127 again:
1128         recow = 0;
1129         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1130         if (ret < 0) {
1131                 err = ret;
1132                 goto fail;
1133         }
1134
1135         if (parent) {
1136                 if (!ret)
1137                         return 0;
1138 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1139                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1140                 btrfs_release_path(path);
1141                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1142                 if (ret < 0) {
1143                         err = ret;
1144                         goto fail;
1145                 }
1146                 if (!ret)
1147                         return 0;
1148 #endif
1149                 goto fail;
1150         }
1151
1152         leaf = path->nodes[0];
1153         nritems = btrfs_header_nritems(leaf);
1154         while (1) {
1155                 if (path->slots[0] >= nritems) {
1156                         ret = btrfs_next_leaf(root, path);
1157                         if (ret < 0)
1158                                 err = ret;
1159                         if (ret)
1160                                 goto fail;
1161
1162                         leaf = path->nodes[0];
1163                         nritems = btrfs_header_nritems(leaf);
1164                         recow = 1;
1165                 }
1166
1167                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1168                 if (key.objectid != bytenr ||
1169                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1170                         goto fail;
1171
1172                 ref = btrfs_item_ptr(leaf, path->slots[0],
1173                                      struct btrfs_extent_data_ref);
1174
1175                 if (match_extent_data_ref(leaf, ref, root_objectid,
1176                                           owner, offset)) {
1177                         if (recow) {
1178                                 btrfs_release_path(path);
1179                                 goto again;
1180                         }
1181                         err = 0;
1182                         break;
1183                 }
1184                 path->slots[0]++;
1185         }
1186 fail:
1187         return err;
1188 }
1189
1190 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1191                                            struct btrfs_root *root,
1192                                            struct btrfs_path *path,
1193                                            u64 bytenr, u64 parent,
1194                                            u64 root_objectid, u64 owner,
1195                                            u64 offset, int refs_to_add)
1196 {
1197         struct btrfs_key key;
1198         struct extent_buffer *leaf;
1199         u32 size;
1200         u32 num_refs;
1201         int ret;
1202
1203         key.objectid = bytenr;
1204         if (parent) {
1205                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1206                 key.offset = parent;
1207                 size = sizeof(struct btrfs_shared_data_ref);
1208         } else {
1209                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1210                 key.offset = hash_extent_data_ref(root_objectid,
1211                                                   owner, offset);
1212                 size = sizeof(struct btrfs_extent_data_ref);
1213         }
1214
1215         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1216         if (ret && ret != -EEXIST)
1217                 goto fail;
1218
1219         leaf = path->nodes[0];
1220         if (parent) {
1221                 struct btrfs_shared_data_ref *ref;
1222                 ref = btrfs_item_ptr(leaf, path->slots[0],
1223                                      struct btrfs_shared_data_ref);
1224                 if (ret == 0) {
1225                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1226                 } else {
1227                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1228                         num_refs += refs_to_add;
1229                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1230                 }
1231         } else {
1232                 struct btrfs_extent_data_ref *ref;
1233                 while (ret == -EEXIST) {
1234                         ref = btrfs_item_ptr(leaf, path->slots[0],
1235                                              struct btrfs_extent_data_ref);
1236                         if (match_extent_data_ref(leaf, ref, root_objectid,
1237                                                   owner, offset))
1238                                 break;
1239                         btrfs_release_path(path);
1240                         key.offset++;
1241                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1242                                                       size);
1243                         if (ret && ret != -EEXIST)
1244                                 goto fail;
1245
1246                         leaf = path->nodes[0];
1247                 }
1248                 ref = btrfs_item_ptr(leaf, path->slots[0],
1249                                      struct btrfs_extent_data_ref);
1250                 if (ret == 0) {
1251                         btrfs_set_extent_data_ref_root(leaf, ref,
1252                                                        root_objectid);
1253                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1254                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1255                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1256                 } else {
1257                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1258                         num_refs += refs_to_add;
1259                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1260                 }
1261         }
1262         btrfs_mark_buffer_dirty(leaf);
1263         ret = 0;
1264 fail:
1265         btrfs_release_path(path);
1266         return ret;
1267 }
1268
1269 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1270                                            struct btrfs_root *root,
1271                                            struct btrfs_path *path,
1272                                            int refs_to_drop)
1273 {
1274         struct btrfs_key key;
1275         struct btrfs_extent_data_ref *ref1 = NULL;
1276         struct btrfs_shared_data_ref *ref2 = NULL;
1277         struct extent_buffer *leaf;
1278         u32 num_refs = 0;
1279         int ret = 0;
1280
1281         leaf = path->nodes[0];
1282         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1283
1284         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1285                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1286                                       struct btrfs_extent_data_ref);
1287                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1288         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1289                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1290                                       struct btrfs_shared_data_ref);
1291                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1292 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1293         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1294                 struct btrfs_extent_ref_v0 *ref0;
1295                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1296                                       struct btrfs_extent_ref_v0);
1297                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1298 #endif
1299         } else {
1300                 BUG();
1301         }
1302
1303         BUG_ON(num_refs < refs_to_drop);
1304         num_refs -= refs_to_drop;
1305
1306         if (num_refs == 0) {
1307                 ret = btrfs_del_item(trans, root, path);
1308         } else {
1309                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1310                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1311                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1312                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1313 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1314                 else {
1315                         struct btrfs_extent_ref_v0 *ref0;
1316                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1317                                         struct btrfs_extent_ref_v0);
1318                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1319                 }
1320 #endif
1321                 btrfs_mark_buffer_dirty(leaf);
1322         }
1323         return ret;
1324 }
1325
1326 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1327                                           struct btrfs_path *path,
1328                                           struct btrfs_extent_inline_ref *iref)
1329 {
1330         struct btrfs_key key;
1331         struct extent_buffer *leaf;
1332         struct btrfs_extent_data_ref *ref1;
1333         struct btrfs_shared_data_ref *ref2;
1334         u32 num_refs = 0;
1335
1336         leaf = path->nodes[0];
1337         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1338         if (iref) {
1339                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1340                     BTRFS_EXTENT_DATA_REF_KEY) {
1341                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1342                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1343                 } else {
1344                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1345                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1346                 }
1347         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1348                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1349                                       struct btrfs_extent_data_ref);
1350                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1351         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1352                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1353                                       struct btrfs_shared_data_ref);
1354                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1355 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1356         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1357                 struct btrfs_extent_ref_v0 *ref0;
1358                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1359                                       struct btrfs_extent_ref_v0);
1360                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1361 #endif
1362         } else {
1363                 WARN_ON(1);
1364         }
1365         return num_refs;
1366 }
1367
1368 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1369                                           struct btrfs_root *root,
1370                                           struct btrfs_path *path,
1371                                           u64 bytenr, u64 parent,
1372                                           u64 root_objectid)
1373 {
1374         struct btrfs_key key;
1375         int ret;
1376
1377         key.objectid = bytenr;
1378         if (parent) {
1379                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1380                 key.offset = parent;
1381         } else {
1382                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1383                 key.offset = root_objectid;
1384         }
1385
1386         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1387         if (ret > 0)
1388                 ret = -ENOENT;
1389 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1390         if (ret == -ENOENT && parent) {
1391                 btrfs_release_path(path);
1392                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1393                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1394                 if (ret > 0)
1395                         ret = -ENOENT;
1396         }
1397 #endif
1398         return ret;
1399 }
1400
1401 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1402                                           struct btrfs_root *root,
1403                                           struct btrfs_path *path,
1404                                           u64 bytenr, u64 parent,
1405                                           u64 root_objectid)
1406 {
1407         struct btrfs_key key;
1408         int ret;
1409
1410         key.objectid = bytenr;
1411         if (parent) {
1412                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1413                 key.offset = parent;
1414         } else {
1415                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1416                 key.offset = root_objectid;
1417         }
1418
1419         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1420         btrfs_release_path(path);
1421         return ret;
1422 }
1423
1424 static inline int extent_ref_type(u64 parent, u64 owner)
1425 {
1426         int type;
1427         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1428                 if (parent > 0)
1429                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1430                 else
1431                         type = BTRFS_TREE_BLOCK_REF_KEY;
1432         } else {
1433                 if (parent > 0)
1434                         type = BTRFS_SHARED_DATA_REF_KEY;
1435                 else
1436                         type = BTRFS_EXTENT_DATA_REF_KEY;
1437         }
1438         return type;
1439 }
1440
1441 static int find_next_key(struct btrfs_path *path, int level,
1442                          struct btrfs_key *key)
1443
1444 {
1445         for (; level < BTRFS_MAX_LEVEL; level++) {
1446                 if (!path->nodes[level])
1447                         break;
1448                 if (path->slots[level] + 1 >=
1449                     btrfs_header_nritems(path->nodes[level]))
1450                         continue;
1451                 if (level == 0)
1452                         btrfs_item_key_to_cpu(path->nodes[level], key,
1453                                               path->slots[level] + 1);
1454                 else
1455                         btrfs_node_key_to_cpu(path->nodes[level], key,
1456                                               path->slots[level] + 1);
1457                 return 0;
1458         }
1459         return 1;
1460 }
1461
1462 /*
1463  * look for inline back ref. if back ref is found, *ref_ret is set
1464  * to the address of inline back ref, and 0 is returned.
1465  *
1466  * if back ref isn't found, *ref_ret is set to the address where it
1467  * should be inserted, and -ENOENT is returned.
1468  *
1469  * if insert is true and there are too many inline back refs, the path
1470  * points to the extent item, and -EAGAIN is returned.
1471  *
1472  * NOTE: inline back refs are ordered in the same way that back ref
1473  *       items in the tree are ordered.
1474  */
1475 static noinline_for_stack
1476 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1477                                  struct btrfs_root *root,
1478                                  struct btrfs_path *path,
1479                                  struct btrfs_extent_inline_ref **ref_ret,
1480                                  u64 bytenr, u64 num_bytes,
1481                                  u64 parent, u64 root_objectid,
1482                                  u64 owner, u64 offset, int insert)
1483 {
1484         struct btrfs_key key;
1485         struct extent_buffer *leaf;
1486         struct btrfs_extent_item *ei;
1487         struct btrfs_extent_inline_ref *iref;
1488         u64 flags;
1489         u64 item_size;
1490         unsigned long ptr;
1491         unsigned long end;
1492         int extra_size;
1493         int type;
1494         int want;
1495         int ret;
1496         int err = 0;
1497         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1498                                                  SKINNY_METADATA);
1499
1500         key.objectid = bytenr;
1501         key.type = BTRFS_EXTENT_ITEM_KEY;
1502         key.offset = num_bytes;
1503
1504         want = extent_ref_type(parent, owner);
1505         if (insert) {
1506                 extra_size = btrfs_extent_inline_ref_size(want);
1507                 path->keep_locks = 1;
1508         } else
1509                 extra_size = -1;
1510
1511         /*
1512          * Owner is our parent level, so we can just add one to get the level
1513          * for the block we are interested in.
1514          */
1515         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1516                 key.type = BTRFS_METADATA_ITEM_KEY;
1517                 key.offset = owner;
1518         }
1519
1520 again:
1521         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1522         if (ret < 0) {
1523                 err = ret;
1524                 goto out;
1525         }
1526
1527         /*
1528          * We may be a newly converted file system which still has the old fat
1529          * extent entries for metadata, so try and see if we have one of those.
1530          */
1531         if (ret > 0 && skinny_metadata) {
1532                 skinny_metadata = false;
1533                 if (path->slots[0]) {
1534                         path->slots[0]--;
1535                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1536                                               path->slots[0]);
1537                         if (key.objectid == bytenr &&
1538                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1539                             key.offset == num_bytes)
1540                                 ret = 0;
1541                 }
1542                 if (ret) {
1543                         key.type = BTRFS_EXTENT_ITEM_KEY;
1544                         key.offset = num_bytes;
1545                         btrfs_release_path(path);
1546                         goto again;
1547                 }
1548         }
1549
1550         if (ret && !insert) {
1551                 err = -ENOENT;
1552                 goto out;
1553         } else if (WARN_ON(ret)) {
1554                 err = -EIO;
1555                 goto out;
1556         }
1557
1558         leaf = path->nodes[0];
1559         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1560 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1561         if (item_size < sizeof(*ei)) {
1562                 if (!insert) {
1563                         err = -ENOENT;
1564                         goto out;
1565                 }
1566                 ret = convert_extent_item_v0(trans, root, path, owner,
1567                                              extra_size);
1568                 if (ret < 0) {
1569                         err = ret;
1570                         goto out;
1571                 }
1572                 leaf = path->nodes[0];
1573                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1574         }
1575 #endif
1576         BUG_ON(item_size < sizeof(*ei));
1577
1578         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1579         flags = btrfs_extent_flags(leaf, ei);
1580
1581         ptr = (unsigned long)(ei + 1);
1582         end = (unsigned long)ei + item_size;
1583
1584         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1585                 ptr += sizeof(struct btrfs_tree_block_info);
1586                 BUG_ON(ptr > end);
1587         }
1588
1589         err = -ENOENT;
1590         while (1) {
1591                 if (ptr >= end) {
1592                         WARN_ON(ptr > end);
1593                         break;
1594                 }
1595                 iref = (struct btrfs_extent_inline_ref *)ptr;
1596                 type = btrfs_extent_inline_ref_type(leaf, iref);
1597                 if (want < type)
1598                         break;
1599                 if (want > type) {
1600                         ptr += btrfs_extent_inline_ref_size(type);
1601                         continue;
1602                 }
1603
1604                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1605                         struct btrfs_extent_data_ref *dref;
1606                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1607                         if (match_extent_data_ref(leaf, dref, root_objectid,
1608                                                   owner, offset)) {
1609                                 err = 0;
1610                                 break;
1611                         }
1612                         if (hash_extent_data_ref_item(leaf, dref) <
1613                             hash_extent_data_ref(root_objectid, owner, offset))
1614                                 break;
1615                 } else {
1616                         u64 ref_offset;
1617                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1618                         if (parent > 0) {
1619                                 if (parent == ref_offset) {
1620                                         err = 0;
1621                                         break;
1622                                 }
1623                                 if (ref_offset < parent)
1624                                         break;
1625                         } else {
1626                                 if (root_objectid == ref_offset) {
1627                                         err = 0;
1628                                         break;
1629                                 }
1630                                 if (ref_offset < root_objectid)
1631                                         break;
1632                         }
1633                 }
1634                 ptr += btrfs_extent_inline_ref_size(type);
1635         }
1636         if (err == -ENOENT && insert) {
1637                 if (item_size + extra_size >=
1638                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1639                         err = -EAGAIN;
1640                         goto out;
1641                 }
1642                 /*
1643                  * To add new inline back ref, we have to make sure
1644                  * there is no corresponding back ref item.
1645                  * For simplicity, we just do not add new inline back
1646                  * ref if there is any kind of item for this block
1647                  */
1648                 if (find_next_key(path, 0, &key) == 0 &&
1649                     key.objectid == bytenr &&
1650                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1651                         err = -EAGAIN;
1652                         goto out;
1653                 }
1654         }
1655         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1656 out:
1657         if (insert) {
1658                 path->keep_locks = 0;
1659                 btrfs_unlock_up_safe(path, 1);
1660         }
1661         return err;
1662 }
1663
1664 /*
1665  * helper to add new inline back ref
1666  */
1667 static noinline_for_stack
1668 void setup_inline_extent_backref(struct btrfs_root *root,
1669                                  struct btrfs_path *path,
1670                                  struct btrfs_extent_inline_ref *iref,
1671                                  u64 parent, u64 root_objectid,
1672                                  u64 owner, u64 offset, int refs_to_add,
1673                                  struct btrfs_delayed_extent_op *extent_op)
1674 {
1675         struct extent_buffer *leaf;
1676         struct btrfs_extent_item *ei;
1677         unsigned long ptr;
1678         unsigned long end;
1679         unsigned long item_offset;
1680         u64 refs;
1681         int size;
1682         int type;
1683
1684         leaf = path->nodes[0];
1685         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1686         item_offset = (unsigned long)iref - (unsigned long)ei;
1687
1688         type = extent_ref_type(parent, owner);
1689         size = btrfs_extent_inline_ref_size(type);
1690
1691         btrfs_extend_item(root, path, size);
1692
1693         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1694         refs = btrfs_extent_refs(leaf, ei);
1695         refs += refs_to_add;
1696         btrfs_set_extent_refs(leaf, ei, refs);
1697         if (extent_op)
1698                 __run_delayed_extent_op(extent_op, leaf, ei);
1699
1700         ptr = (unsigned long)ei + item_offset;
1701         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1702         if (ptr < end - size)
1703                 memmove_extent_buffer(leaf, ptr + size, ptr,
1704                                       end - size - ptr);
1705
1706         iref = (struct btrfs_extent_inline_ref *)ptr;
1707         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1708         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1709                 struct btrfs_extent_data_ref *dref;
1710                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1711                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1712                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1713                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1714                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1715         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1716                 struct btrfs_shared_data_ref *sref;
1717                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1718                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1719                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1720         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1722         } else {
1723                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1724         }
1725         btrfs_mark_buffer_dirty(leaf);
1726 }
1727
1728 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1729                                  struct btrfs_root *root,
1730                                  struct btrfs_path *path,
1731                                  struct btrfs_extent_inline_ref **ref_ret,
1732                                  u64 bytenr, u64 num_bytes, u64 parent,
1733                                  u64 root_objectid, u64 owner, u64 offset)
1734 {
1735         int ret;
1736
1737         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1738                                            bytenr, num_bytes, parent,
1739                                            root_objectid, owner, offset, 0);
1740         if (ret != -ENOENT)
1741                 return ret;
1742
1743         btrfs_release_path(path);
1744         *ref_ret = NULL;
1745
1746         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1747                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1748                                             root_objectid);
1749         } else {
1750                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1751                                              root_objectid, owner, offset);
1752         }
1753         return ret;
1754 }
1755
1756 /*
1757  * helper to update/remove inline back ref
1758  */
1759 static noinline_for_stack
1760 void update_inline_extent_backref(struct btrfs_root *root,
1761                                   struct btrfs_path *path,
1762                                   struct btrfs_extent_inline_ref *iref,
1763                                   int refs_to_mod,
1764                                   struct btrfs_delayed_extent_op *extent_op)
1765 {
1766         struct extent_buffer *leaf;
1767         struct btrfs_extent_item *ei;
1768         struct btrfs_extent_data_ref *dref = NULL;
1769         struct btrfs_shared_data_ref *sref = NULL;
1770         unsigned long ptr;
1771         unsigned long end;
1772         u32 item_size;
1773         int size;
1774         int type;
1775         u64 refs;
1776
1777         leaf = path->nodes[0];
1778         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1779         refs = btrfs_extent_refs(leaf, ei);
1780         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1781         refs += refs_to_mod;
1782         btrfs_set_extent_refs(leaf, ei, refs);
1783         if (extent_op)
1784                 __run_delayed_extent_op(extent_op, leaf, ei);
1785
1786         type = btrfs_extent_inline_ref_type(leaf, iref);
1787
1788         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1789                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1790                 refs = btrfs_extent_data_ref_count(leaf, dref);
1791         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1792                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1793                 refs = btrfs_shared_data_ref_count(leaf, sref);
1794         } else {
1795                 refs = 1;
1796                 BUG_ON(refs_to_mod != -1);
1797         }
1798
1799         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1800         refs += refs_to_mod;
1801
1802         if (refs > 0) {
1803                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1804                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1805                 else
1806                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1807         } else {
1808                 size =  btrfs_extent_inline_ref_size(type);
1809                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1810                 ptr = (unsigned long)iref;
1811                 end = (unsigned long)ei + item_size;
1812                 if (ptr + size < end)
1813                         memmove_extent_buffer(leaf, ptr, ptr + size,
1814                                               end - ptr - size);
1815                 item_size -= size;
1816                 btrfs_truncate_item(root, path, item_size, 1);
1817         }
1818         btrfs_mark_buffer_dirty(leaf);
1819 }
1820
1821 static noinline_for_stack
1822 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1823                                  struct btrfs_root *root,
1824                                  struct btrfs_path *path,
1825                                  u64 bytenr, u64 num_bytes, u64 parent,
1826                                  u64 root_objectid, u64 owner,
1827                                  u64 offset, int refs_to_add,
1828                                  struct btrfs_delayed_extent_op *extent_op)
1829 {
1830         struct btrfs_extent_inline_ref *iref;
1831         int ret;
1832
1833         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1834                                            bytenr, num_bytes, parent,
1835                                            root_objectid, owner, offset, 1);
1836         if (ret == 0) {
1837                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1838                 update_inline_extent_backref(root, path, iref,
1839                                              refs_to_add, extent_op);
1840         } else if (ret == -ENOENT) {
1841                 setup_inline_extent_backref(root, path, iref, parent,
1842                                             root_objectid, owner, offset,
1843                                             refs_to_add, extent_op);
1844                 ret = 0;
1845         }
1846         return ret;
1847 }
1848
1849 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1850                                  struct btrfs_root *root,
1851                                  struct btrfs_path *path,
1852                                  u64 bytenr, u64 parent, u64 root_objectid,
1853                                  u64 owner, u64 offset, int refs_to_add)
1854 {
1855         int ret;
1856         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1857                 BUG_ON(refs_to_add != 1);
1858                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1859                                             parent, root_objectid);
1860         } else {
1861                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1862                                              parent, root_objectid,
1863                                              owner, offset, refs_to_add);
1864         }
1865         return ret;
1866 }
1867
1868 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1869                                  struct btrfs_root *root,
1870                                  struct btrfs_path *path,
1871                                  struct btrfs_extent_inline_ref *iref,
1872                                  int refs_to_drop, int is_data)
1873 {
1874         int ret = 0;
1875
1876         BUG_ON(!is_data && refs_to_drop != 1);
1877         if (iref) {
1878                 update_inline_extent_backref(root, path, iref,
1879                                              -refs_to_drop, NULL);
1880         } else if (is_data) {
1881                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1882         } else {
1883                 ret = btrfs_del_item(trans, root, path);
1884         }
1885         return ret;
1886 }
1887
1888 static int btrfs_issue_discard(struct block_device *bdev,
1889                                 u64 start, u64 len)
1890 {
1891         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1892 }
1893
1894 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1895                                 u64 num_bytes, u64 *actual_bytes)
1896 {
1897         int ret;
1898         u64 discarded_bytes = 0;
1899         struct btrfs_bio *bbio = NULL;
1900
1901
1902         /* Tell the block device(s) that the sectors can be discarded */
1903         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1904                               bytenr, &num_bytes, &bbio, 0);
1905         /* Error condition is -ENOMEM */
1906         if (!ret) {
1907                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1908                 int i;
1909
1910
1911                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1912                         if (!stripe->dev->can_discard)
1913                                 continue;
1914
1915                         ret = btrfs_issue_discard(stripe->dev->bdev,
1916                                                   stripe->physical,
1917                                                   stripe->length);
1918                         if (!ret)
1919                                 discarded_bytes += stripe->length;
1920                         else if (ret != -EOPNOTSUPP)
1921                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1922
1923                         /*
1924                          * Just in case we get back EOPNOTSUPP for some reason,
1925                          * just ignore the return value so we don't screw up
1926                          * people calling discard_extent.
1927                          */
1928                         ret = 0;
1929                 }
1930                 kfree(bbio);
1931         }
1932
1933         if (actual_bytes)
1934                 *actual_bytes = discarded_bytes;
1935
1936
1937         if (ret == -EOPNOTSUPP)
1938                 ret = 0;
1939         return ret;
1940 }
1941
1942 /* Can return -ENOMEM */
1943 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1944                          struct btrfs_root *root,
1945                          u64 bytenr, u64 num_bytes, u64 parent,
1946                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
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, for_cow);
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, for_cow);
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                                   struct btrfs_delayed_extent_op *extent_op)
1974 {
1975         struct btrfs_path *path;
1976         struct extent_buffer *leaf;
1977         struct btrfs_extent_item *item;
1978         u64 refs;
1979         int ret;
1980
1981         path = btrfs_alloc_path();
1982         if (!path)
1983                 return -ENOMEM;
1984
1985         path->reada = 1;
1986         path->leave_spinning = 1;
1987         /* this will setup the path even if it fails to insert the back ref */
1988         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1989                                            path, bytenr, num_bytes, parent,
1990                                            root_objectid, owner, offset,
1991                                            refs_to_add, extent_op);
1992         if (ret != -EAGAIN)
1993                 goto out;
1994
1995         leaf = path->nodes[0];
1996         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1997         refs = btrfs_extent_refs(leaf, item);
1998         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1999         if (extent_op)
2000                 __run_delayed_extent_op(extent_op, leaf, item);
2001
2002         btrfs_mark_buffer_dirty(leaf);
2003         btrfs_release_path(path);
2004
2005         path->reada = 1;
2006         path->leave_spinning = 1;
2007
2008         /* now insert the actual backref */
2009         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2010                                     path, bytenr, parent, root_objectid,
2011                                     owner, offset, refs_to_add);
2012         if (ret)
2013                 btrfs_abort_transaction(trans, root, ret);
2014 out:
2015         btrfs_free_path(path);
2016         return ret;
2017 }
2018
2019 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2020                                 struct btrfs_root *root,
2021                                 struct btrfs_delayed_ref_node *node,
2022                                 struct btrfs_delayed_extent_op *extent_op,
2023                                 int insert_reserved)
2024 {
2025         int ret = 0;
2026         struct btrfs_delayed_data_ref *ref;
2027         struct btrfs_key ins;
2028         u64 parent = 0;
2029         u64 ref_root = 0;
2030         u64 flags = 0;
2031
2032         ins.objectid = node->bytenr;
2033         ins.offset = node->num_bytes;
2034         ins.type = BTRFS_EXTENT_ITEM_KEY;
2035
2036         ref = btrfs_delayed_node_to_data_ref(node);
2037         trace_run_delayed_data_ref(node, ref, node->action);
2038
2039         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2040                 parent = ref->parent;
2041         else
2042                 ref_root = ref->root;
2043
2044         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2045                 if (extent_op)
2046                         flags |= extent_op->flags_to_set;
2047                 ret = alloc_reserved_file_extent(trans, root,
2048                                                  parent, ref_root, flags,
2049                                                  ref->objectid, ref->offset,
2050                                                  &ins, node->ref_mod);
2051         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2052                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2053                                              node->num_bytes, parent,
2054                                              ref_root, ref->objectid,
2055                                              ref->offset, node->ref_mod,
2056                                              extent_op);
2057         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2058                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2059                                           node->num_bytes, parent,
2060                                           ref_root, ref->objectid,
2061                                           ref->offset, node->ref_mod,
2062                                           extent_op);
2063         } else {
2064                 BUG();
2065         }
2066         return ret;
2067 }
2068
2069 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2070                                     struct extent_buffer *leaf,
2071                                     struct btrfs_extent_item *ei)
2072 {
2073         u64 flags = btrfs_extent_flags(leaf, ei);
2074         if (extent_op->update_flags) {
2075                 flags |= extent_op->flags_to_set;
2076                 btrfs_set_extent_flags(leaf, ei, flags);
2077         }
2078
2079         if (extent_op->update_key) {
2080                 struct btrfs_tree_block_info *bi;
2081                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2082                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2083                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2084         }
2085 }
2086
2087 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2088                                  struct btrfs_root *root,
2089                                  struct btrfs_delayed_ref_node *node,
2090                                  struct btrfs_delayed_extent_op *extent_op)
2091 {
2092         struct btrfs_key key;
2093         struct btrfs_path *path;
2094         struct btrfs_extent_item *ei;
2095         struct extent_buffer *leaf;
2096         u32 item_size;
2097         int ret;
2098         int err = 0;
2099         int metadata = !extent_op->is_data;
2100
2101         if (trans->aborted)
2102                 return 0;
2103
2104         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2105                 metadata = 0;
2106
2107         path = btrfs_alloc_path();
2108         if (!path)
2109                 return -ENOMEM;
2110
2111         key.objectid = node->bytenr;
2112
2113         if (metadata) {
2114                 key.type = BTRFS_METADATA_ITEM_KEY;
2115                 key.offset = extent_op->level;
2116         } else {
2117                 key.type = BTRFS_EXTENT_ITEM_KEY;
2118                 key.offset = node->num_bytes;
2119         }
2120
2121 again:
2122         path->reada = 1;
2123         path->leave_spinning = 1;
2124         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2125                                 path, 0, 1);
2126         if (ret < 0) {
2127                 err = ret;
2128                 goto out;
2129         }
2130         if (ret > 0) {
2131                 if (metadata) {
2132                         if (path->slots[0] > 0) {
2133                                 path->slots[0]--;
2134                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2135                                                       path->slots[0]);
2136                                 if (key.objectid == node->bytenr &&
2137                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2138                                     key.offset == node->num_bytes)
2139                                         ret = 0;
2140                         }
2141                         if (ret > 0) {
2142                                 btrfs_release_path(path);
2143                                 metadata = 0;
2144
2145                                 key.objectid = node->bytenr;
2146                                 key.offset = node->num_bytes;
2147                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2148                                 goto again;
2149                         }
2150                 } else {
2151                         err = -EIO;
2152                         goto out;
2153                 }
2154         }
2155
2156         leaf = path->nodes[0];
2157         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2158 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2159         if (item_size < sizeof(*ei)) {
2160                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2161                                              path, (u64)-1, 0);
2162                 if (ret < 0) {
2163                         err = ret;
2164                         goto out;
2165                 }
2166                 leaf = path->nodes[0];
2167                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2168         }
2169 #endif
2170         BUG_ON(item_size < sizeof(*ei));
2171         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2172         __run_delayed_extent_op(extent_op, leaf, ei);
2173
2174         btrfs_mark_buffer_dirty(leaf);
2175 out:
2176         btrfs_free_path(path);
2177         return err;
2178 }
2179
2180 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2181                                 struct btrfs_root *root,
2182                                 struct btrfs_delayed_ref_node *node,
2183                                 struct btrfs_delayed_extent_op *extent_op,
2184                                 int insert_reserved)
2185 {
2186         int ret = 0;
2187         struct btrfs_delayed_tree_ref *ref;
2188         struct btrfs_key ins;
2189         u64 parent = 0;
2190         u64 ref_root = 0;
2191         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2192                                                  SKINNY_METADATA);
2193
2194         ref = btrfs_delayed_node_to_tree_ref(node);
2195         trace_run_delayed_tree_ref(node, ref, node->action);
2196
2197         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2198                 parent = ref->parent;
2199         else
2200                 ref_root = ref->root;
2201
2202         ins.objectid = node->bytenr;
2203         if (skinny_metadata) {
2204                 ins.offset = ref->level;
2205                 ins.type = BTRFS_METADATA_ITEM_KEY;
2206         } else {
2207                 ins.offset = node->num_bytes;
2208                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2209         }
2210
2211         BUG_ON(node->ref_mod != 1);
2212         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2213                 BUG_ON(!extent_op || !extent_op->update_flags);
2214                 ret = alloc_reserved_tree_block(trans, root,
2215                                                 parent, ref_root,
2216                                                 extent_op->flags_to_set,
2217                                                 &extent_op->key,
2218                                                 ref->level, &ins);
2219         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2220                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2221                                              node->num_bytes, parent, ref_root,
2222                                              ref->level, 0, 1, extent_op);
2223         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2224                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2225                                           node->num_bytes, parent, ref_root,
2226                                           ref->level, 0, 1, extent_op);
2227         } else {
2228                 BUG();
2229         }
2230         return ret;
2231 }
2232
2233 /* helper function to actually process a single delayed ref entry */
2234 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2235                                struct btrfs_root *root,
2236                                struct btrfs_delayed_ref_node *node,
2237                                struct btrfs_delayed_extent_op *extent_op,
2238                                int insert_reserved)
2239 {
2240         int ret = 0;
2241
2242         if (trans->aborted) {
2243                 if (insert_reserved)
2244                         btrfs_pin_extent(root, node->bytenr,
2245                                          node->num_bytes, 1);
2246                 return 0;
2247         }
2248
2249         if (btrfs_delayed_ref_is_head(node)) {
2250                 struct btrfs_delayed_ref_head *head;
2251                 /*
2252                  * we've hit the end of the chain and we were supposed
2253                  * to insert this extent into the tree.  But, it got
2254                  * deleted before we ever needed to insert it, so all
2255                  * we have to do is clean up the accounting
2256                  */
2257                 BUG_ON(extent_op);
2258                 head = btrfs_delayed_node_to_head(node);
2259                 trace_run_delayed_ref_head(node, head, node->action);
2260
2261                 if (insert_reserved) {
2262                         btrfs_pin_extent(root, node->bytenr,
2263                                          node->num_bytes, 1);
2264                         if (head->is_data) {
2265                                 ret = btrfs_del_csums(trans, root,
2266                                                       node->bytenr,
2267                                                       node->num_bytes);
2268                         }
2269                 }
2270                 return ret;
2271         }
2272
2273         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2274             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2275                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2276                                            insert_reserved);
2277         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2278                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2279                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2280                                            insert_reserved);
2281         else
2282                 BUG();
2283         return ret;
2284 }
2285
2286 static noinline struct btrfs_delayed_ref_node *
2287 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2288 {
2289         struct rb_node *node;
2290         struct btrfs_delayed_ref_node *ref;
2291         int action = BTRFS_ADD_DELAYED_REF;
2292 again:
2293         /*
2294          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2295          * this prevents ref count from going down to zero when
2296          * there still are pending delayed ref.
2297          */
2298         node = rb_prev(&head->node.rb_node);
2299         while (1) {
2300                 if (!node)
2301                         break;
2302                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2303                                 rb_node);
2304                 if (ref->bytenr != head->node.bytenr)
2305                         break;
2306                 if (ref->action == action)
2307                         return ref;
2308                 node = rb_prev(node);
2309         }
2310         if (action == BTRFS_ADD_DELAYED_REF) {
2311                 action = BTRFS_DROP_DELAYED_REF;
2312                 goto again;
2313         }
2314         return NULL;
2315 }
2316
2317 /*
2318  * Returns 0 on success or if called with an already aborted transaction.
2319  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2320  */
2321 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2322                                        struct btrfs_root *root,
2323                                        struct list_head *cluster)
2324 {
2325         struct btrfs_delayed_ref_root *delayed_refs;
2326         struct btrfs_delayed_ref_node *ref;
2327         struct btrfs_delayed_ref_head *locked_ref = NULL;
2328         struct btrfs_delayed_extent_op *extent_op;
2329         struct btrfs_fs_info *fs_info = root->fs_info;
2330         int ret;
2331         int count = 0;
2332         int must_insert_reserved = 0;
2333
2334         delayed_refs = &trans->transaction->delayed_refs;
2335         while (1) {
2336                 if (!locked_ref) {
2337                         /* pick a new head ref from the cluster list */
2338                         if (list_empty(cluster))
2339                                 break;
2340
2341                         locked_ref = list_entry(cluster->next,
2342                                      struct btrfs_delayed_ref_head, cluster);
2343
2344                         /* grab the lock that says we are going to process
2345                          * all the refs for this head */
2346                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2347
2348                         /*
2349                          * we may have dropped the spin lock to get the head
2350                          * mutex lock, and that might have given someone else
2351                          * time to free the head.  If that's true, it has been
2352                          * removed from our list and we can move on.
2353                          */
2354                         if (ret == -EAGAIN) {
2355                                 locked_ref = NULL;
2356                                 count++;
2357                                 continue;
2358                         }
2359                 }
2360
2361                 /*
2362                  * We need to try and merge add/drops of the same ref since we
2363                  * can run into issues with relocate dropping the implicit ref
2364                  * and then it being added back again before the drop can
2365                  * finish.  If we merged anything we need to re-loop so we can
2366                  * get a good ref.
2367                  */
2368                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2369                                          locked_ref);
2370
2371                 /*
2372                  * locked_ref is the head node, so we have to go one
2373                  * node back for any delayed ref updates
2374                  */
2375                 ref = select_delayed_ref(locked_ref);
2376
2377                 if (ref && ref->seq &&
2378                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2379                         /*
2380                          * there are still refs with lower seq numbers in the
2381                          * process of being added. Don't run this ref yet.
2382                          */
2383                         list_del_init(&locked_ref->cluster);
2384                         btrfs_delayed_ref_unlock(locked_ref);
2385                         locked_ref = NULL;
2386                         delayed_refs->num_heads_ready++;
2387                         spin_unlock(&delayed_refs->lock);
2388                         cond_resched();
2389                         spin_lock(&delayed_refs->lock);
2390                         continue;
2391                 }
2392
2393                 /*
2394                  * record the must insert reserved flag before we
2395                  * drop the spin lock.
2396                  */
2397                 must_insert_reserved = locked_ref->must_insert_reserved;
2398                 locked_ref->must_insert_reserved = 0;
2399
2400                 extent_op = locked_ref->extent_op;
2401                 locked_ref->extent_op = NULL;
2402
2403                 if (!ref) {
2404                         /* All delayed refs have been processed, Go ahead
2405                          * and send the head node to run_one_delayed_ref,
2406                          * so that any accounting fixes can happen
2407                          */
2408                         ref = &locked_ref->node;
2409
2410                         if (extent_op && must_insert_reserved) {
2411                                 btrfs_free_delayed_extent_op(extent_op);
2412                                 extent_op = NULL;
2413                         }
2414
2415                         if (extent_op) {
2416                                 spin_unlock(&delayed_refs->lock);
2417
2418                                 ret = run_delayed_extent_op(trans, root,
2419                                                             ref, extent_op);
2420                                 btrfs_free_delayed_extent_op(extent_op);
2421
2422                                 if (ret) {
2423                                         /*
2424                                          * Need to reset must_insert_reserved if
2425                                          * there was an error so the abort stuff
2426                                          * can cleanup the reserved space
2427                                          * properly.
2428                                          */
2429                                         if (must_insert_reserved)
2430                                                 locked_ref->must_insert_reserved = 1;
2431                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2432                                         spin_lock(&delayed_refs->lock);
2433                                         btrfs_delayed_ref_unlock(locked_ref);
2434                                         return ret;
2435                                 }
2436
2437                                 goto next;
2438                         }
2439                 }
2440
2441                 ref->in_tree = 0;
2442                 rb_erase(&ref->rb_node, &delayed_refs->root);
2443                 if (btrfs_delayed_ref_is_head(ref)) {
2444                         rb_erase(&locked_ref->href_node,
2445                                  &delayed_refs->href_root);
2446                 }
2447                 delayed_refs->num_entries--;
2448                 if (!btrfs_delayed_ref_is_head(ref)) {
2449                         /*
2450                          * when we play the delayed ref, also correct the
2451                          * ref_mod on head
2452                          */
2453                         switch (ref->action) {
2454                         case BTRFS_ADD_DELAYED_REF:
2455                         case BTRFS_ADD_DELAYED_EXTENT:
2456                                 locked_ref->node.ref_mod -= ref->ref_mod;
2457                                 break;
2458                         case BTRFS_DROP_DELAYED_REF:
2459                                 locked_ref->node.ref_mod += ref->ref_mod;
2460                                 break;
2461                         default:
2462                                 WARN_ON(1);
2463                         }
2464                 } else {
2465                         list_del_init(&locked_ref->cluster);
2466                 }
2467                 spin_unlock(&delayed_refs->lock);
2468
2469                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2470                                           must_insert_reserved);
2471
2472                 btrfs_free_delayed_extent_op(extent_op);
2473                 if (ret) {
2474                         btrfs_delayed_ref_unlock(locked_ref);
2475                         btrfs_put_delayed_ref(ref);
2476                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2477                         spin_lock(&delayed_refs->lock);
2478                         return ret;
2479                 }
2480
2481                 /*
2482                  * If this node is a head, that means all the refs in this head
2483                  * have been dealt with, and we will pick the next head to deal
2484                  * with, so we must unlock the head and drop it from the cluster
2485                  * list before we release it.
2486                  */
2487                 if (btrfs_delayed_ref_is_head(ref)) {
2488                         btrfs_delayed_ref_unlock(locked_ref);
2489                         locked_ref = NULL;
2490                 }
2491                 btrfs_put_delayed_ref(ref);
2492                 count++;
2493 next:
2494                 cond_resched();
2495                 spin_lock(&delayed_refs->lock);
2496         }
2497         return count;
2498 }
2499
2500 #ifdef SCRAMBLE_DELAYED_REFS
2501 /*
2502  * Normally delayed refs get processed in ascending bytenr order. This
2503  * correlates in most cases to the order added. To expose dependencies on this
2504  * order, we start to process the tree in the middle instead of the beginning
2505  */
2506 static u64 find_middle(struct rb_root *root)
2507 {
2508         struct rb_node *n = root->rb_node;
2509         struct btrfs_delayed_ref_node *entry;
2510         int alt = 1;
2511         u64 middle;
2512         u64 first = 0, last = 0;
2513
2514         n = rb_first(root);
2515         if (n) {
2516                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2517                 first = entry->bytenr;
2518         }
2519         n = rb_last(root);
2520         if (n) {
2521                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2522                 last = entry->bytenr;
2523         }
2524         n = root->rb_node;
2525
2526         while (n) {
2527                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2528                 WARN_ON(!entry->in_tree);
2529
2530                 middle = entry->bytenr;
2531
2532                 if (alt)
2533                         n = n->rb_left;
2534                 else
2535                         n = n->rb_right;
2536
2537                 alt = 1 - alt;
2538         }
2539         return middle;
2540 }
2541 #endif
2542
2543 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2544                                          struct btrfs_fs_info *fs_info)
2545 {
2546         struct qgroup_update *qgroup_update;
2547         int ret = 0;
2548
2549         if (list_empty(&trans->qgroup_ref_list) !=
2550             !trans->delayed_ref_elem.seq) {
2551                 /* list without seq or seq without list */
2552                 btrfs_err(fs_info,
2553                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2554                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2555                         (u32)(trans->delayed_ref_elem.seq >> 32),
2556                         (u32)trans->delayed_ref_elem.seq);
2557                 BUG();
2558         }
2559
2560         if (!trans->delayed_ref_elem.seq)
2561                 return 0;
2562
2563         while (!list_empty(&trans->qgroup_ref_list)) {
2564                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2565                                                  struct qgroup_update, list);
2566                 list_del(&qgroup_update->list);
2567                 if (!ret)
2568                         ret = btrfs_qgroup_account_ref(
2569                                         trans, fs_info, qgroup_update->node,
2570                                         qgroup_update->extent_op);
2571                 kfree(qgroup_update);
2572         }
2573
2574         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2575
2576         return ret;
2577 }
2578
2579 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2580                       int count)
2581 {
2582         int val = atomic_read(&delayed_refs->ref_seq);
2583
2584         if (val < seq || val >= seq + count)
2585                 return 1;
2586         return 0;
2587 }
2588
2589 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2590 {
2591         u64 num_bytes;
2592
2593         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2594                              sizeof(struct btrfs_extent_inline_ref));
2595         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2596                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2597
2598         /*
2599          * We don't ever fill up leaves all the way so multiply by 2 just to be
2600          * closer to what we're really going to want to ouse.
2601          */
2602         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2603 }
2604
2605 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2606                                        struct btrfs_root *root)
2607 {
2608         struct btrfs_block_rsv *global_rsv;
2609         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2610         u64 num_bytes;
2611         int ret = 0;
2612
2613         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2614         num_heads = heads_to_leaves(root, num_heads);
2615         if (num_heads > 1)
2616                 num_bytes += (num_heads - 1) * root->leafsize;
2617         num_bytes <<= 1;
2618         global_rsv = &root->fs_info->global_block_rsv;
2619
2620         /*
2621          * If we can't allocate any more chunks lets make sure we have _lots_ of
2622          * wiggle room since running delayed refs can create more delayed refs.
2623          */
2624         if (global_rsv->space_info->full)
2625                 num_bytes <<= 1;
2626
2627         spin_lock(&global_rsv->lock);
2628         if (global_rsv->reserved <= num_bytes)
2629                 ret = 1;
2630         spin_unlock(&global_rsv->lock);
2631         return ret;
2632 }
2633
2634 /*
2635  * this starts processing the delayed reference count updates and
2636  * extent insertions we have queued up so far.  count can be
2637  * 0, which means to process everything in the tree at the start
2638  * of the run (but not newly added entries), or it can be some target
2639  * number you'd like to process.
2640  *
2641  * Returns 0 on success or if called with an aborted transaction
2642  * Returns <0 on error and aborts the transaction
2643  */
2644 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2645                            struct btrfs_root *root, unsigned long count)
2646 {
2647         struct rb_node *node;
2648         struct btrfs_delayed_ref_root *delayed_refs;
2649         struct btrfs_delayed_ref_head *head;
2650         struct list_head cluster;
2651         int ret;
2652         u64 delayed_start;
2653         int run_all = count == (unsigned long)-1;
2654         int run_most = 0;
2655         int loops;
2656
2657         /* We'll clean this up in btrfs_cleanup_transaction */
2658         if (trans->aborted)
2659                 return 0;
2660
2661         if (root == root->fs_info->extent_root)
2662                 root = root->fs_info->tree_root;
2663
2664         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2665
2666         delayed_refs = &trans->transaction->delayed_refs;
2667         INIT_LIST_HEAD(&cluster);
2668         if (count == 0) {
2669                 count = delayed_refs->num_entries * 2;
2670                 run_most = 1;
2671         }
2672
2673         if (!run_all && !run_most) {
2674                 int old;
2675                 int seq = atomic_read(&delayed_refs->ref_seq);
2676
2677 progress:
2678                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2679                 if (old) {
2680                         DEFINE_WAIT(__wait);
2681                         if (delayed_refs->flushing ||
2682                             !btrfs_should_throttle_delayed_refs(trans, root))
2683                                 return 0;
2684
2685                         prepare_to_wait(&delayed_refs->wait, &__wait,
2686                                         TASK_UNINTERRUPTIBLE);
2687
2688                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2689                         if (old) {
2690                                 schedule();
2691                                 finish_wait(&delayed_refs->wait, &__wait);
2692
2693                                 if (!refs_newer(delayed_refs, seq, 256))
2694                                         goto progress;
2695                                 else
2696                                         return 0;
2697                         } else {
2698                                 finish_wait(&delayed_refs->wait, &__wait);
2699                                 goto again;
2700                         }
2701                 }
2702
2703         } else {
2704                 atomic_inc(&delayed_refs->procs_running_refs);
2705         }
2706
2707 again:
2708         loops = 0;
2709         spin_lock(&delayed_refs->lock);
2710
2711 #ifdef SCRAMBLE_DELAYED_REFS
2712         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2713 #endif
2714
2715         while (1) {
2716                 if (!(run_all || run_most) &&
2717                     !btrfs_should_throttle_delayed_refs(trans, root))
2718                         break;
2719
2720                 /*
2721                  * go find something we can process in the rbtree.  We start at
2722                  * the beginning of the tree, and then build a cluster
2723                  * of refs to process starting at the first one we are able to
2724                  * lock
2725                  */
2726                 delayed_start = delayed_refs->run_delayed_start;
2727                 ret = btrfs_find_ref_cluster(trans, &cluster,
2728                                              delayed_refs->run_delayed_start);
2729                 if (ret)
2730                         break;
2731
2732                 ret = run_clustered_refs(trans, root, &cluster);
2733                 if (ret < 0) {
2734                         btrfs_release_ref_cluster(&cluster);
2735                         spin_unlock(&delayed_refs->lock);
2736                         btrfs_abort_transaction(trans, root, ret);
2737                         atomic_dec(&delayed_refs->procs_running_refs);
2738                         wake_up(&delayed_refs->wait);
2739                         return ret;
2740                 }
2741
2742                 atomic_add(ret, &delayed_refs->ref_seq);
2743
2744                 count -= min_t(unsigned long, ret, count);
2745
2746                 if (count == 0)
2747                         break;
2748
2749                 if (delayed_start >= delayed_refs->run_delayed_start) {
2750                         if (loops == 0) {
2751                                 /*
2752                                  * btrfs_find_ref_cluster looped. let's do one
2753                                  * more cycle. if we don't run any delayed ref
2754                                  * during that cycle (because we can't because
2755                                  * all of them are blocked), bail out.
2756                                  */
2757                                 loops = 1;
2758                         } else {
2759                                 /*
2760                                  * no runnable refs left, stop trying
2761                                  */
2762                                 BUG_ON(run_all);
2763                                 break;
2764                         }
2765                 }
2766                 if (ret) {
2767                         /* refs were run, let's reset staleness detection */
2768                         loops = 0;
2769                 }
2770         }
2771
2772         if (run_all) {
2773                 if (!list_empty(&trans->new_bgs)) {
2774                         spin_unlock(&delayed_refs->lock);
2775                         btrfs_create_pending_block_groups(trans, root);
2776                         spin_lock(&delayed_refs->lock);
2777                 }
2778
2779                 node = rb_first(&delayed_refs->href_root);
2780                 if (!node)
2781                         goto out;
2782                 count = (unsigned long)-1;
2783
2784                 while (node) {
2785                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2786                                         href_node);
2787                         if (btrfs_delayed_ref_is_head(&head->node)) {
2788                                 struct btrfs_delayed_ref_node *ref;
2789
2790                                 ref = &head->node;
2791                                 atomic_inc(&ref->refs);
2792
2793                                 spin_unlock(&delayed_refs->lock);
2794                                 /*
2795                                  * Mutex was contended, block until it's
2796                                  * released and try again
2797                                  */
2798                                 mutex_lock(&head->mutex);
2799                                 mutex_unlock(&head->mutex);
2800
2801                                 btrfs_put_delayed_ref(ref);
2802                                 cond_resched();
2803                                 goto again;
2804                         } else {
2805                                 WARN_ON(1);
2806                         }
2807                         node = rb_next(node);
2808                 }
2809                 spin_unlock(&delayed_refs->lock);
2810                 schedule_timeout(1);
2811                 goto again;
2812         }
2813 out:
2814         atomic_dec(&delayed_refs->procs_running_refs);
2815         smp_mb();
2816         if (waitqueue_active(&delayed_refs->wait))
2817                 wake_up(&delayed_refs->wait);
2818
2819         spin_unlock(&delayed_refs->lock);
2820         assert_qgroups_uptodate(trans);
2821         return 0;
2822 }
2823
2824 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2825                                 struct btrfs_root *root,
2826                                 u64 bytenr, u64 num_bytes, u64 flags,
2827                                 int level, int is_data)
2828 {
2829         struct btrfs_delayed_extent_op *extent_op;
2830         int ret;
2831
2832         extent_op = btrfs_alloc_delayed_extent_op();
2833         if (!extent_op)
2834                 return -ENOMEM;
2835
2836         extent_op->flags_to_set = flags;
2837         extent_op->update_flags = 1;
2838         extent_op->update_key = 0;
2839         extent_op->is_data = is_data ? 1 : 0;
2840         extent_op->level = level;
2841
2842         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2843                                           num_bytes, extent_op);
2844         if (ret)
2845                 btrfs_free_delayed_extent_op(extent_op);
2846         return ret;
2847 }
2848
2849 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2850                                       struct btrfs_root *root,
2851                                       struct btrfs_path *path,
2852                                       u64 objectid, u64 offset, u64 bytenr)
2853 {
2854         struct btrfs_delayed_ref_head *head;
2855         struct btrfs_delayed_ref_node *ref;
2856         struct btrfs_delayed_data_ref *data_ref;
2857         struct btrfs_delayed_ref_root *delayed_refs;
2858         struct rb_node *node;
2859         int ret = 0;
2860
2861         ret = -ENOENT;
2862         delayed_refs = &trans->transaction->delayed_refs;
2863         spin_lock(&delayed_refs->lock);
2864         head = btrfs_find_delayed_ref_head(trans, bytenr);
2865         if (!head)
2866                 goto out;
2867
2868         if (!mutex_trylock(&head->mutex)) {
2869                 atomic_inc(&head->node.refs);
2870                 spin_unlock(&delayed_refs->lock);
2871
2872                 btrfs_release_path(path);
2873
2874                 /*
2875                  * Mutex was contended, block until it's released and let
2876                  * caller try again
2877                  */
2878                 mutex_lock(&head->mutex);
2879                 mutex_unlock(&head->mutex);
2880                 btrfs_put_delayed_ref(&head->node);
2881                 return -EAGAIN;
2882         }
2883
2884         node = rb_prev(&head->node.rb_node);
2885         if (!node)
2886                 goto out_unlock;
2887
2888         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2889
2890         if (ref->bytenr != bytenr)
2891                 goto out_unlock;
2892
2893         ret = 1;
2894         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2895                 goto out_unlock;
2896
2897         data_ref = btrfs_delayed_node_to_data_ref(ref);
2898
2899         node = rb_prev(node);
2900         if (node) {
2901                 int seq = ref->seq;
2902
2903                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2904                 if (ref->bytenr == bytenr && ref->seq == seq)
2905                         goto out_unlock;
2906         }
2907
2908         if (data_ref->root != root->root_key.objectid ||
2909             data_ref->objectid != objectid || data_ref->offset != offset)
2910                 goto out_unlock;
2911
2912         ret = 0;
2913 out_unlock:
2914         mutex_unlock(&head->mutex);
2915 out:
2916         spin_unlock(&delayed_refs->lock);
2917         return ret;
2918 }
2919
2920 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2921                                         struct btrfs_root *root,
2922                                         struct btrfs_path *path,
2923                                         u64 objectid, u64 offset, u64 bytenr)
2924 {
2925         struct btrfs_root *extent_root = root->fs_info->extent_root;
2926         struct extent_buffer *leaf;
2927         struct btrfs_extent_data_ref *ref;
2928         struct btrfs_extent_inline_ref *iref;
2929         struct btrfs_extent_item *ei;
2930         struct btrfs_key key;
2931         u32 item_size;
2932         int ret;
2933
2934         key.objectid = bytenr;
2935         key.offset = (u64)-1;
2936         key.type = BTRFS_EXTENT_ITEM_KEY;
2937
2938         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2939         if (ret < 0)
2940                 goto out;
2941         BUG_ON(ret == 0); /* Corruption */
2942
2943         ret = -ENOENT;
2944         if (path->slots[0] == 0)
2945                 goto out;
2946
2947         path->slots[0]--;
2948         leaf = path->nodes[0];
2949         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2950
2951         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2952                 goto out;
2953
2954         ret = 1;
2955         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2956 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2957         if (item_size < sizeof(*ei)) {
2958                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2959                 goto out;
2960         }
2961 #endif
2962         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2963
2964         if (item_size != sizeof(*ei) +
2965             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2966                 goto out;
2967
2968         if (btrfs_extent_generation(leaf, ei) <=
2969             btrfs_root_last_snapshot(&root->root_item))
2970                 goto out;
2971
2972         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2973         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2974             BTRFS_EXTENT_DATA_REF_KEY)
2975                 goto out;
2976
2977         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2978         if (btrfs_extent_refs(leaf, ei) !=
2979             btrfs_extent_data_ref_count(leaf, ref) ||
2980             btrfs_extent_data_ref_root(leaf, ref) !=
2981             root->root_key.objectid ||
2982             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2983             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2984                 goto out;
2985
2986         ret = 0;
2987 out:
2988         return ret;
2989 }
2990
2991 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2992                           struct btrfs_root *root,
2993                           u64 objectid, u64 offset, u64 bytenr)
2994 {
2995         struct btrfs_path *path;
2996         int ret;
2997         int ret2;
2998
2999         path = btrfs_alloc_path();
3000         if (!path)
3001                 return -ENOENT;
3002
3003         do {
3004                 ret = check_committed_ref(trans, root, path, objectid,
3005                                           offset, bytenr);
3006                 if (ret && ret != -ENOENT)
3007                         goto out;
3008
3009                 ret2 = check_delayed_ref(trans, root, path, objectid,
3010                                          offset, bytenr);
3011         } while (ret2 == -EAGAIN);
3012
3013         if (ret2 && ret2 != -ENOENT) {
3014                 ret = ret2;
3015                 goto out;
3016         }
3017
3018         if (ret != -ENOENT || ret2 != -ENOENT)
3019                 ret = 0;
3020 out:
3021         btrfs_free_path(path);
3022         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3023                 WARN_ON(ret > 0);
3024         return ret;
3025 }
3026
3027 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3028                            struct btrfs_root *root,
3029                            struct extent_buffer *buf,
3030                            int full_backref, int inc, int for_cow)
3031 {
3032         u64 bytenr;
3033         u64 num_bytes;
3034         u64 parent;
3035         u64 ref_root;
3036         u32 nritems;
3037         struct btrfs_key key;
3038         struct btrfs_file_extent_item *fi;
3039         int i;
3040         int level;
3041         int ret = 0;
3042         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3043                             u64, u64, u64, u64, u64, u64, int);
3044
3045         ref_root = btrfs_header_owner(buf);
3046         nritems = btrfs_header_nritems(buf);
3047         level = btrfs_header_level(buf);
3048
3049         if (!root->ref_cows && level == 0)
3050                 return 0;
3051
3052         if (inc)
3053                 process_func = btrfs_inc_extent_ref;
3054         else
3055                 process_func = btrfs_free_extent;
3056
3057         if (full_backref)
3058                 parent = buf->start;
3059         else
3060                 parent = 0;
3061
3062         for (i = 0; i < nritems; i++) {
3063                 if (level == 0) {
3064                         btrfs_item_key_to_cpu(buf, &key, i);
3065                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3066                                 continue;
3067                         fi = btrfs_item_ptr(buf, i,
3068                                             struct btrfs_file_extent_item);
3069                         if (btrfs_file_extent_type(buf, fi) ==
3070                             BTRFS_FILE_EXTENT_INLINE)
3071                                 continue;
3072                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3073                         if (bytenr == 0)
3074                                 continue;
3075
3076                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3077                         key.offset -= btrfs_file_extent_offset(buf, fi);
3078                         ret = process_func(trans, root, bytenr, num_bytes,
3079                                            parent, ref_root, key.objectid,
3080                                            key.offset, for_cow);
3081                         if (ret)
3082                                 goto fail;
3083                 } else {
3084                         bytenr = btrfs_node_blockptr(buf, i);
3085                         num_bytes = btrfs_level_size(root, level - 1);
3086                         ret = process_func(trans, root, bytenr, num_bytes,
3087                                            parent, ref_root, level - 1, 0,
3088                                            for_cow);
3089                         if (ret)
3090                                 goto fail;
3091                 }
3092         }
3093         return 0;
3094 fail:
3095         return ret;
3096 }
3097
3098 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3099                   struct extent_buffer *buf, int full_backref, int for_cow)
3100 {
3101         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3102 }
3103
3104 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3105                   struct extent_buffer *buf, int full_backref, int for_cow)
3106 {
3107         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3108 }
3109
3110 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3111                                  struct btrfs_root *root,
3112                                  struct btrfs_path *path,
3113                                  struct btrfs_block_group_cache *cache)
3114 {
3115         int ret;
3116         struct btrfs_root *extent_root = root->fs_info->extent_root;
3117         unsigned long bi;
3118         struct extent_buffer *leaf;
3119
3120         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3121         if (ret < 0)
3122                 goto fail;
3123         BUG_ON(ret); /* Corruption */
3124
3125         leaf = path->nodes[0];
3126         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3127         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3128         btrfs_mark_buffer_dirty(leaf);
3129         btrfs_release_path(path);
3130 fail:
3131         if (ret) {
3132                 btrfs_abort_transaction(trans, root, ret);
3133                 return ret;
3134         }
3135         return 0;
3136
3137 }
3138
3139 static struct btrfs_block_group_cache *
3140 next_block_group(struct btrfs_root *root,
3141                  struct btrfs_block_group_cache *cache)
3142 {
3143         struct rb_node *node;
3144         spin_lock(&root->fs_info->block_group_cache_lock);
3145         node = rb_next(&cache->cache_node);
3146         btrfs_put_block_group(cache);
3147         if (node) {
3148                 cache = rb_entry(node, struct btrfs_block_group_cache,
3149                                  cache_node);
3150                 btrfs_get_block_group(cache);
3151         } else
3152                 cache = NULL;
3153         spin_unlock(&root->fs_info->block_group_cache_lock);
3154         return cache;
3155 }
3156
3157 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3158                             struct btrfs_trans_handle *trans,
3159                             struct btrfs_path *path)
3160 {
3161         struct btrfs_root *root = block_group->fs_info->tree_root;
3162         struct inode *inode = NULL;
3163         u64 alloc_hint = 0;
3164         int dcs = BTRFS_DC_ERROR;
3165         int num_pages = 0;
3166         int retries = 0;
3167         int ret = 0;
3168
3169         /*
3170          * If this block group is smaller than 100 megs don't bother caching the
3171          * block group.
3172          */
3173         if (block_group->key.offset < (100 * 1024 * 1024)) {
3174                 spin_lock(&block_group->lock);
3175                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3176                 spin_unlock(&block_group->lock);
3177                 return 0;
3178         }
3179
3180 again:
3181         inode = lookup_free_space_inode(root, block_group, path);
3182         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3183                 ret = PTR_ERR(inode);
3184                 btrfs_release_path(path);
3185                 goto out;
3186         }
3187
3188         if (IS_ERR(inode)) {
3189                 BUG_ON(retries);
3190                 retries++;
3191
3192                 if (block_group->ro)
3193                         goto out_free;
3194
3195                 ret = create_free_space_inode(root, trans, block_group, path);
3196                 if (ret)
3197                         goto out_free;
3198                 goto again;
3199         }
3200
3201         /* We've already setup this transaction, go ahead and exit */
3202         if (block_group->cache_generation == trans->transid &&
3203             i_size_read(inode)) {
3204                 dcs = BTRFS_DC_SETUP;
3205                 goto out_put;
3206         }
3207
3208         /*
3209          * We want to set the generation to 0, that way if anything goes wrong
3210          * from here on out we know not to trust this cache when we load up next
3211          * time.
3212          */
3213         BTRFS_I(inode)->generation = 0;
3214         ret = btrfs_update_inode(trans, root, inode);
3215         WARN_ON(ret);
3216
3217         if (i_size_read(inode) > 0) {
3218                 ret = btrfs_check_trunc_cache_free_space(root,
3219                                         &root->fs_info->global_block_rsv);
3220                 if (ret)
3221                         goto out_put;
3222
3223                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3224                 if (ret)
3225                         goto out_put;
3226         }
3227
3228         spin_lock(&block_group->lock);
3229         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3230             !btrfs_test_opt(root, SPACE_CACHE)) {
3231                 /*
3232                  * don't bother trying to write stuff out _if_
3233                  * a) we're not cached,
3234                  * b) we're with nospace_cache mount option.
3235                  */
3236                 dcs = BTRFS_DC_WRITTEN;
3237                 spin_unlock(&block_group->lock);
3238                 goto out_put;
3239         }
3240         spin_unlock(&block_group->lock);
3241
3242         /*
3243          * Try to preallocate enough space based on how big the block group is.
3244          * Keep in mind this has to include any pinned space which could end up
3245          * taking up quite a bit since it's not folded into the other space
3246          * cache.
3247          */
3248         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3249         if (!num_pages)
3250                 num_pages = 1;
3251
3252         num_pages *= 16;
3253         num_pages *= PAGE_CACHE_SIZE;
3254
3255         ret = btrfs_check_data_free_space(inode, num_pages);
3256         if (ret)
3257                 goto out_put;
3258
3259         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3260                                               num_pages, num_pages,
3261                                               &alloc_hint);
3262         if (!ret)
3263                 dcs = BTRFS_DC_SETUP;
3264         btrfs_free_reserved_data_space(inode, num_pages);
3265
3266 out_put:
3267         iput(inode);
3268 out_free:
3269         btrfs_release_path(path);
3270 out:
3271         spin_lock(&block_group->lock);
3272         if (!ret && dcs == BTRFS_DC_SETUP)
3273                 block_group->cache_generation = trans->transid;
3274         block_group->disk_cache_state = dcs;
3275         spin_unlock(&block_group->lock);
3276
3277         return ret;
3278 }
3279
3280 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3281                                    struct btrfs_root *root)
3282 {
3283         struct btrfs_block_group_cache *cache;
3284         int err = 0;
3285         struct btrfs_path *path;
3286         u64 last = 0;
3287
3288         path = btrfs_alloc_path();
3289         if (!path)
3290                 return -ENOMEM;
3291
3292 again:
3293         while (1) {
3294                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3295                 while (cache) {
3296                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3297                                 break;
3298                         cache = next_block_group(root, cache);
3299                 }
3300                 if (!cache) {
3301                         if (last == 0)
3302                                 break;
3303                         last = 0;
3304                         continue;
3305                 }
3306                 err = cache_save_setup(cache, trans, path);
3307                 last = cache->key.objectid + cache->key.offset;
3308                 btrfs_put_block_group(cache);
3309         }
3310
3311         while (1) {
3312                 if (last == 0) {
3313                         err = btrfs_run_delayed_refs(trans, root,
3314                                                      (unsigned long)-1);
3315                         if (err) /* File system offline */
3316                                 goto out;
3317                 }
3318
3319                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3320                 while (cache) {
3321                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3322                                 btrfs_put_block_group(cache);
3323                                 goto again;
3324                         }
3325
3326                         if (cache->dirty)
3327                                 break;
3328                         cache = next_block_group(root, cache);
3329                 }
3330                 if (!cache) {
3331                         if (last == 0)
3332                                 break;
3333                         last = 0;
3334                         continue;
3335                 }
3336
3337                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3338                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3339                 cache->dirty = 0;
3340                 last = cache->key.objectid + cache->key.offset;
3341
3342                 err = write_one_cache_group(trans, root, path, cache);
3343                 btrfs_put_block_group(cache);
3344                 if (err) /* File system offline */
3345                         goto out;
3346         }
3347
3348         while (1) {
3349                 /*
3350                  * I don't think this is needed since we're just marking our
3351                  * preallocated extent as written, but just in case it can't
3352                  * hurt.
3353                  */
3354                 if (last == 0) {
3355                         err = btrfs_run_delayed_refs(trans, root,
3356                                                      (unsigned long)-1);
3357                         if (err) /* File system offline */
3358                                 goto out;
3359                 }
3360
3361                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3362                 while (cache) {
3363                         /*
3364                          * Really this shouldn't happen, but it could if we
3365                          * couldn't write the entire preallocated extent and
3366                          * splitting the extent resulted in a new block.
3367                          */
3368                         if (cache->dirty) {
3369                                 btrfs_put_block_group(cache);
3370                                 goto again;
3371                         }
3372                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3373                                 break;
3374                         cache = next_block_group(root, cache);
3375                 }
3376                 if (!cache) {
3377                         if (last == 0)
3378                                 break;
3379                         last = 0;
3380                         continue;
3381                 }
3382
3383                 err = btrfs_write_out_cache(root, trans, cache, path);
3384
3385                 /*
3386                  * If we didn't have an error then the cache state is still
3387                  * NEED_WRITE, so we can set it to WRITTEN.
3388                  */
3389                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3390                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3391                 last = cache->key.objectid + cache->key.offset;
3392                 btrfs_put_block_group(cache);
3393         }
3394 out:
3395
3396         btrfs_free_path(path);
3397         return err;
3398 }
3399
3400 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3401 {
3402         struct btrfs_block_group_cache *block_group;
3403         int readonly = 0;
3404
3405         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3406         if (!block_group || block_group->ro)
3407                 readonly = 1;
3408         if (block_group)
3409                 btrfs_put_block_group(block_group);
3410         return readonly;
3411 }
3412
3413 static const char *alloc_name(u64 flags)
3414 {
3415         switch (flags) {
3416         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3417                 return "mixed";
3418         case BTRFS_BLOCK_GROUP_METADATA:
3419                 return "metadata";
3420         case BTRFS_BLOCK_GROUP_DATA:
3421                 return "data";
3422         case BTRFS_BLOCK_GROUP_SYSTEM:
3423                 return "system";
3424         default:
3425                 WARN_ON(1);
3426                 return "invalid-combination";
3427         };
3428 }
3429
3430 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3431                              u64 total_bytes, u64 bytes_used,
3432                              struct btrfs_space_info **space_info)
3433 {
3434         struct btrfs_space_info *found;
3435         int i;
3436         int factor;
3437         int ret;
3438
3439         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3440                      BTRFS_BLOCK_GROUP_RAID10))
3441                 factor = 2;
3442         else
3443                 factor = 1;
3444
3445         found = __find_space_info(info, flags);
3446         if (found) {
3447                 spin_lock(&found->lock);
3448                 found->total_bytes += total_bytes;
3449                 found->disk_total += total_bytes * factor;
3450                 found->bytes_used += bytes_used;
3451                 found->disk_used += bytes_used * factor;
3452                 found->full = 0;
3453                 spin_unlock(&found->lock);
3454                 *space_info = found;
3455                 return 0;
3456         }
3457         found = kzalloc(sizeof(*found), GFP_NOFS);
3458         if (!found)
3459                 return -ENOMEM;
3460
3461         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3462         if (ret) {
3463                 kfree(found);
3464                 return ret;
3465         }
3466
3467         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
3468                 INIT_LIST_HEAD(&found->block_groups[i]);
3469                 kobject_init(&found->block_group_kobjs[i], &btrfs_raid_ktype);
3470         }
3471         init_rwsem(&found->groups_sem);
3472         spin_lock_init(&found->lock);
3473         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3474         found->total_bytes = total_bytes;
3475         found->disk_total = total_bytes * factor;
3476         found->bytes_used = bytes_used;
3477         found->disk_used = bytes_used * factor;
3478         found->bytes_pinned = 0;
3479         found->bytes_reserved = 0;
3480         found->bytes_readonly = 0;
3481         found->bytes_may_use = 0;
3482         found->full = 0;
3483         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3484         found->chunk_alloc = 0;
3485         found->flush = 0;
3486         init_waitqueue_head(&found->wait);
3487
3488         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3489                                     info->space_info_kobj, "%s",
3490                                     alloc_name(found->flags));
3491         if (ret) {
3492                 kfree(found);
3493                 return ret;
3494         }
3495
3496         *space_info = found;
3497         list_add_rcu(&found->list, &info->space_info);
3498         if (flags & BTRFS_BLOCK_GROUP_DATA)
3499                 info->data_sinfo = found;
3500
3501         return ret;
3502 }
3503
3504 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3505 {
3506         u64 extra_flags = chunk_to_extended(flags) &
3507                                 BTRFS_EXTENDED_PROFILE_MASK;
3508
3509         write_seqlock(&fs_info->profiles_lock);
3510         if (flags & BTRFS_BLOCK_GROUP_DATA)
3511                 fs_info->avail_data_alloc_bits |= extra_flags;
3512         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3513                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3514         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3515                 fs_info->avail_system_alloc_bits |= extra_flags;
3516         write_sequnlock(&fs_info->profiles_lock);
3517 }
3518
3519 /*
3520  * returns target flags in extended format or 0 if restripe for this
3521  * chunk_type is not in progress
3522  *
3523  * should be called with either volume_mutex or balance_lock held
3524  */
3525 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3526 {
3527         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3528         u64 target = 0;
3529
3530         if (!bctl)
3531                 return 0;
3532
3533         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3534             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3535                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3536         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3537                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3538                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3539         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3540                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3541                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3542         }
3543
3544         return target;
3545 }
3546
3547 /*
3548  * @flags: available profiles in extended format (see ctree.h)
3549  *
3550  * Returns reduced profile in chunk format.  If profile changing is in
3551  * progress (either running or paused) picks the target profile (if it's
3552  * already available), otherwise falls back to plain reducing.
3553  */
3554 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3555 {
3556         /*
3557          * we add in the count of missing devices because we want
3558          * to make sure that any RAID levels on a degraded FS
3559          * continue to be honored.
3560          */
3561         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3562                 root->fs_info->fs_devices->missing_devices;
3563         u64 target;
3564         u64 tmp;
3565
3566         /*
3567          * see if restripe for this chunk_type is in progress, if so
3568          * try to reduce to the target profile
3569          */
3570         spin_lock(&root->fs_info->balance_lock);
3571         target = get_restripe_target(root->fs_info, flags);
3572         if (target) {
3573                 /* pick target profile only if it's already available */
3574                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3575                         spin_unlock(&root->fs_info->balance_lock);
3576                         return extended_to_chunk(target);
3577                 }
3578         }
3579         spin_unlock(&root->fs_info->balance_lock);
3580
3581         /* First, mask out the RAID levels which aren't possible */
3582         if (num_devices == 1)
3583                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3584                            BTRFS_BLOCK_GROUP_RAID5);
3585         if (num_devices < 3)
3586                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3587         if (num_devices < 4)
3588                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3589
3590         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3591                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3592                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3593         flags &= ~tmp;
3594
3595         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3596                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3597         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3598                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3599         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3600                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3601         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3602                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3603         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3604                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3605
3606         return extended_to_chunk(flags | tmp);
3607 }
3608
3609 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3610 {
3611         unsigned seq;
3612
3613         do {
3614                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3615
3616                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3617                         flags |= root->fs_info->avail_data_alloc_bits;
3618                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3619                         flags |= root->fs_info->avail_system_alloc_bits;
3620                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3621                         flags |= root->fs_info->avail_metadata_alloc_bits;
3622         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3623
3624         return btrfs_reduce_alloc_profile(root, flags);
3625 }
3626
3627 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3628 {
3629         u64 flags;
3630         u64 ret;
3631
3632         if (data)
3633                 flags = BTRFS_BLOCK_GROUP_DATA;
3634         else if (root == root->fs_info->chunk_root)
3635                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3636         else
3637                 flags = BTRFS_BLOCK_GROUP_METADATA;
3638
3639         ret = get_alloc_profile(root, flags);
3640         return ret;
3641 }
3642
3643 /*
3644  * This will check the space that the inode allocates from to make sure we have
3645  * enough space for bytes.
3646  */
3647 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3648 {
3649         struct btrfs_space_info *data_sinfo;
3650         struct btrfs_root *root = BTRFS_I(inode)->root;
3651         struct btrfs_fs_info *fs_info = root->fs_info;
3652         u64 used;
3653         int ret = 0, committed = 0, alloc_chunk = 1;
3654
3655         /* make sure bytes are sectorsize aligned */
3656         bytes = ALIGN(bytes, root->sectorsize);
3657
3658         if (btrfs_is_free_space_inode(inode)) {
3659                 committed = 1;
3660                 ASSERT(current->journal_info);
3661         }
3662
3663         data_sinfo = fs_info->data_sinfo;
3664         if (!data_sinfo)
3665                 goto alloc;
3666
3667 again:
3668         /* make sure we have enough space to handle the data first */
3669         spin_lock(&data_sinfo->lock);
3670         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3671                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3672                 data_sinfo->bytes_may_use;
3673
3674         if (used + bytes > data_sinfo->total_bytes) {
3675                 struct btrfs_trans_handle *trans;
3676
3677                 /*
3678                  * if we don't have enough free bytes in this space then we need
3679                  * to alloc a new chunk.
3680                  */
3681                 if (!data_sinfo->full && alloc_chunk) {
3682                         u64 alloc_target;
3683
3684                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3685                         spin_unlock(&data_sinfo->lock);
3686 alloc:
3687                         alloc_target = btrfs_get_alloc_profile(root, 1);
3688                         /*
3689                          * It is ugly that we don't call nolock join
3690                          * transaction for the free space inode case here.
3691                          * But it is safe because we only do the data space
3692                          * reservation for the free space cache in the
3693                          * transaction context, the common join transaction
3694                          * just increase the counter of the current transaction
3695                          * handler, doesn't try to acquire the trans_lock of
3696                          * the fs.
3697                          */
3698                         trans = btrfs_join_transaction(root);
3699                         if (IS_ERR(trans))
3700                                 return PTR_ERR(trans);
3701
3702                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3703                                              alloc_target,
3704                                              CHUNK_ALLOC_NO_FORCE);
3705                         btrfs_end_transaction(trans, root);
3706                         if (ret < 0) {
3707                                 if (ret != -ENOSPC)
3708                                         return ret;
3709                                 else
3710                                         goto commit_trans;
3711                         }
3712
3713                         if (!data_sinfo)
3714                                 data_sinfo = fs_info->data_sinfo;
3715
3716                         goto again;
3717                 }
3718
3719                 /*
3720                  * If we don't have enough pinned space to deal with this
3721                  * allocation don't bother committing the transaction.
3722                  */
3723                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3724                                            bytes) < 0)
3725                         committed = 1;
3726                 spin_unlock(&data_sinfo->lock);
3727
3728                 /* commit the current transaction and try again */
3729 commit_trans:
3730                 if (!committed &&
3731                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3732                         committed = 1;
3733
3734                         trans = btrfs_join_transaction(root);
3735                         if (IS_ERR(trans))
3736                                 return PTR_ERR(trans);
3737                         ret = btrfs_commit_transaction(trans, root);
3738                         if (ret)
3739                                 return ret;
3740                         goto again;
3741                 }
3742
3743                 trace_btrfs_space_reservation(root->fs_info,
3744                                               "space_info:enospc",
3745                                               data_sinfo->flags, bytes, 1);
3746                 return -ENOSPC;
3747         }
3748         data_sinfo->bytes_may_use += bytes;
3749         trace_btrfs_space_reservation(root->fs_info, "space_info",
3750                                       data_sinfo->flags, bytes, 1);
3751         spin_unlock(&data_sinfo->lock);
3752
3753         return 0;
3754 }
3755
3756 /*
3757  * Called if we need to clear a data reservation for this inode.
3758  */
3759 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3760 {
3761         struct btrfs_root *root = BTRFS_I(inode)->root;
3762         struct btrfs_space_info *data_sinfo;
3763
3764         /* make sure bytes are sectorsize aligned */
3765         bytes = ALIGN(bytes, root->sectorsize);
3766
3767         data_sinfo = root->fs_info->data_sinfo;
3768         spin_lock(&data_sinfo->lock);
3769         WARN_ON(data_sinfo->bytes_may_use < bytes);
3770         data_sinfo->bytes_may_use -= bytes;
3771         trace_btrfs_space_reservation(root->fs_info, "space_info",
3772                                       data_sinfo->flags, bytes, 0);
3773         spin_unlock(&data_sinfo->lock);
3774 }
3775
3776 static void force_metadata_allocation(struct btrfs_fs_info *info)
3777 {
3778         struct list_head *head = &info->space_info;
3779         struct btrfs_space_info *found;
3780
3781         rcu_read_lock();
3782         list_for_each_entry_rcu(found, head, list) {
3783                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3784                         found->force_alloc = CHUNK_ALLOC_FORCE;
3785         }
3786         rcu_read_unlock();
3787 }
3788
3789 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3790 {
3791         return (global->size << 1);
3792 }
3793
3794 static int should_alloc_chunk(struct btrfs_root *root,
3795                               struct btrfs_space_info *sinfo, int force)
3796 {
3797         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3798         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3799         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3800         u64 thresh;
3801
3802         if (force == CHUNK_ALLOC_FORCE)
3803                 return 1;
3804
3805         /*
3806          * We need to take into account the global rsv because for all intents
3807          * and purposes it's used space.  Don't worry about locking the
3808          * global_rsv, it doesn't change except when the transaction commits.
3809          */
3810         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3811                 num_allocated += calc_global_rsv_need_space(global_rsv);
3812
3813         /*
3814          * in limited mode, we want to have some free space up to
3815          * about 1% of the FS size.
3816          */
3817         if (force == CHUNK_ALLOC_LIMITED) {
3818                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3819                 thresh = max_t(u64, 64 * 1024 * 1024,
3820                                div_factor_fine(thresh, 1));
3821
3822                 if (num_bytes - num_allocated < thresh)
3823                         return 1;
3824         }
3825
3826         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3827                 return 0;
3828         return 1;
3829 }
3830
3831 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3832 {
3833         u64 num_dev;
3834
3835         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3836                     BTRFS_BLOCK_GROUP_RAID0 |
3837                     BTRFS_BLOCK_GROUP_RAID5 |
3838                     BTRFS_BLOCK_GROUP_RAID6))
3839                 num_dev = root->fs_info->fs_devices->rw_devices;
3840         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3841                 num_dev = 2;
3842         else
3843                 num_dev = 1;    /* DUP or single */
3844
3845         /* metadata for updaing devices and chunk tree */
3846         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3847 }
3848
3849 static void check_system_chunk(struct btrfs_trans_handle *trans,
3850                                struct btrfs_root *root, u64 type)
3851 {
3852         struct btrfs_space_info *info;
3853         u64 left;
3854         u64 thresh;
3855
3856         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3857         spin_lock(&info->lock);
3858         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3859                 info->bytes_reserved - info->bytes_readonly;
3860         spin_unlock(&info->lock);
3861
3862         thresh = get_system_chunk_thresh(root, type);
3863         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3864                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3865                         left, thresh, type);
3866                 dump_space_info(info, 0, 0);
3867         }
3868
3869         if (left < thresh) {
3870                 u64 flags;
3871
3872                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3873                 btrfs_alloc_chunk(trans, root, flags);
3874         }
3875 }
3876
3877 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3878                           struct btrfs_root *extent_root, u64 flags, int force)
3879 {
3880         struct btrfs_space_info *space_info;
3881         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3882         int wait_for_alloc = 0;
3883         int ret = 0;
3884
3885         /* Don't re-enter if we're already allocating a chunk */
3886         if (trans->allocating_chunk)
3887                 return -ENOSPC;
3888
3889         space_info = __find_space_info(extent_root->fs_info, flags);
3890         if (!space_info) {
3891                 ret = update_space_info(extent_root->fs_info, flags,
3892                                         0, 0, &space_info);
3893                 BUG_ON(ret); /* -ENOMEM */
3894         }
3895         BUG_ON(!space_info); /* Logic error */
3896
3897 again:
3898         spin_lock(&space_info->lock);
3899         if (force < space_info->force_alloc)
3900                 force = space_info->force_alloc;
3901         if (space_info->full) {
3902                 if (should_alloc_chunk(extent_root, space_info, force))
3903                         ret = -ENOSPC;
3904                 else
3905                         ret = 0;
3906                 spin_unlock(&space_info->lock);
3907                 return ret;
3908         }
3909
3910         if (!should_alloc_chunk(extent_root, space_info, force)) {
3911                 spin_unlock(&space_info->lock);
3912                 return 0;
3913         } else if (space_info->chunk_alloc) {
3914                 wait_for_alloc = 1;
3915         } else {
3916                 space_info->chunk_alloc = 1;
3917         }
3918
3919         spin_unlock(&space_info->lock);
3920
3921         mutex_lock(&fs_info->chunk_mutex);
3922
3923         /*
3924          * The chunk_mutex is held throughout the entirety of a chunk
3925          * allocation, so once we've acquired the chunk_mutex we know that the
3926          * other guy is done and we need to recheck and see if we should
3927          * allocate.
3928          */
3929         if (wait_for_alloc) {
3930                 mutex_unlock(&fs_info->chunk_mutex);
3931                 wait_for_alloc = 0;
3932                 goto again;
3933         }
3934
3935         trans->allocating_chunk = true;
3936
3937         /*
3938          * If we have mixed data/metadata chunks we want to make sure we keep
3939          * allocating mixed chunks instead of individual chunks.
3940          */
3941         if (btrfs_mixed_space_info(space_info))
3942                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3943
3944         /*
3945          * if we're doing a data chunk, go ahead and make sure that
3946          * we keep a reasonable number of metadata chunks allocated in the
3947          * FS as well.
3948          */
3949         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3950                 fs_info->data_chunk_allocations++;
3951                 if (!(fs_info->data_chunk_allocations %
3952                       fs_info->metadata_ratio))
3953                         force_metadata_allocation(fs_info);
3954         }
3955
3956         /*
3957          * Check if we have enough space in SYSTEM chunk because we may need
3958          * to update devices.
3959          */
3960         check_system_chunk(trans, extent_root, flags);
3961
3962         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3963         trans->allocating_chunk = false;
3964
3965         spin_lock(&space_info->lock);
3966         if (ret < 0 && ret != -ENOSPC)
3967                 goto out;
3968         if (ret)
3969                 space_info->full = 1;
3970         else
3971                 ret = 1;
3972
3973         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3974 out:
3975         space_info->chunk_alloc = 0;
3976         spin_unlock(&space_info->lock);
3977         mutex_unlock(&fs_info->chunk_mutex);
3978         return ret;
3979 }
3980
3981 static int can_overcommit(struct btrfs_root *root,
3982                           struct btrfs_space_info *space_info, u64 bytes,
3983                           enum btrfs_reserve_flush_enum flush)
3984 {
3985         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3986         u64 profile = btrfs_get_alloc_profile(root, 0);
3987         u64 space_size;
3988         u64 avail;
3989         u64 used;
3990
3991         used = space_info->bytes_used + space_info->bytes_reserved +
3992                 space_info->bytes_pinned + space_info->bytes_readonly;
3993
3994         /*
3995          * We only want to allow over committing if we have lots of actual space
3996          * free, but if we don't have enough space to handle the global reserve
3997          * space then we could end up having a real enospc problem when trying
3998          * to allocate a chunk or some other such important allocation.
3999          */
4000         spin_lock(&global_rsv->lock);
4001         space_size = calc_global_rsv_need_space(global_rsv);
4002         spin_unlock(&global_rsv->lock);
4003         if (used + space_size >= space_info->total_bytes)
4004                 return 0;
4005
4006         used += space_info->bytes_may_use;
4007
4008         spin_lock(&root->fs_info->free_chunk_lock);
4009         avail = root->fs_info->free_chunk_space;
4010         spin_unlock(&root->fs_info->free_chunk_lock);
4011
4012         /*
4013          * If we have dup, raid1 or raid10 then only half of the free
4014          * space is actually useable.  For raid56, the space info used
4015          * doesn't include the parity drive, so we don't have to
4016          * change the math
4017          */
4018         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4019                        BTRFS_BLOCK_GROUP_RAID1 |
4020                        BTRFS_BLOCK_GROUP_RAID10))
4021                 avail >>= 1;
4022
4023         /*
4024          * If we aren't flushing all things, let us overcommit up to
4025          * 1/2th of the space. If we can flush, don't let us overcommit
4026          * too much, let it overcommit up to 1/8 of the space.
4027          */
4028         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4029                 avail >>= 3;
4030         else
4031                 avail >>= 1;
4032
4033         if (used + bytes < space_info->total_bytes + avail)
4034                 return 1;
4035         return 0;
4036 }
4037
4038 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4039                                          unsigned long nr_pages)
4040 {
4041         struct super_block *sb = root->fs_info->sb;
4042
4043         if (down_read_trylock(&sb->s_umount)) {
4044                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4045                 up_read(&sb->s_umount);
4046         } else {
4047                 /*
4048                  * We needn't worry the filesystem going from r/w to r/o though
4049                  * we don't acquire ->s_umount mutex, because the filesystem
4050                  * should guarantee the delalloc inodes list be empty after
4051                  * the filesystem is readonly(all dirty pages are written to
4052                  * the disk).
4053                  */
4054                 btrfs_start_delalloc_roots(root->fs_info, 0);
4055                 if (!current->journal_info)
4056                         btrfs_wait_ordered_roots(root->fs_info, -1);
4057         }
4058 }
4059
4060 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4061 {
4062         u64 bytes;
4063         int nr;
4064
4065         bytes = btrfs_calc_trans_metadata_size(root, 1);
4066         nr = (int)div64_u64(to_reclaim, bytes);
4067         if (!nr)
4068                 nr = 1;
4069         return nr;
4070 }
4071
4072 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4073
4074 /*
4075  * shrink metadata reservation for delalloc
4076  */
4077 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4078                             bool wait_ordered)
4079 {
4080         struct btrfs_block_rsv *block_rsv;
4081         struct btrfs_space_info *space_info;
4082         struct btrfs_trans_handle *trans;
4083         u64 delalloc_bytes;
4084         u64 max_reclaim;
4085         long time_left;
4086         unsigned long nr_pages;
4087         int loops;
4088         int items;
4089         enum btrfs_reserve_flush_enum flush;
4090
4091         /* Calc the number of the pages we need flush for space reservation */
4092         items = calc_reclaim_items_nr(root, to_reclaim);
4093         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4094
4095         trans = (struct btrfs_trans_handle *)current->journal_info;
4096         block_rsv = &root->fs_info->delalloc_block_rsv;
4097         space_info = block_rsv->space_info;
4098
4099         delalloc_bytes = percpu_counter_sum_positive(
4100                                                 &root->fs_info->delalloc_bytes);
4101         if (delalloc_bytes == 0) {
4102                 if (trans)
4103                         return;
4104                 if (wait_ordered)
4105                         btrfs_wait_ordered_roots(root->fs_info, items);
4106                 return;
4107         }
4108
4109         loops = 0;
4110         while (delalloc_bytes && loops < 3) {
4111                 max_reclaim = min(delalloc_bytes, to_reclaim);
4112                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4113                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4114                 /*
4115                  * We need to wait for the async pages to actually start before
4116                  * we do anything.
4117                  */
4118                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4119                 if (!max_reclaim)
4120                         goto skip_async;
4121
4122                 if (max_reclaim <= nr_pages)
4123                         max_reclaim = 0;
4124                 else
4125                         max_reclaim -= nr_pages;
4126
4127                 wait_event(root->fs_info->async_submit_wait,
4128                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4129                            (int)max_reclaim);
4130 skip_async:
4131                 if (!trans)
4132                         flush = BTRFS_RESERVE_FLUSH_ALL;
4133                 else
4134                         flush = BTRFS_RESERVE_NO_FLUSH;
4135                 spin_lock(&space_info->lock);
4136                 if (can_overcommit(root, space_info, orig, flush)) {
4137                         spin_unlock(&space_info->lock);
4138                         break;
4139                 }
4140                 spin_unlock(&space_info->lock);
4141
4142                 loops++;
4143                 if (wait_ordered && !trans) {
4144                         btrfs_wait_ordered_roots(root->fs_info, items);
4145                 } else {
4146                         time_left = schedule_timeout_killable(1);
4147                         if (time_left)
4148                                 break;
4149                 }
4150                 delalloc_bytes = percpu_counter_sum_positive(
4151                                                 &root->fs_info->delalloc_bytes);
4152         }
4153 }
4154
4155 /**
4156  * maybe_commit_transaction - possibly commit the transaction if its ok to
4157  * @root - the root we're allocating for
4158  * @bytes - the number of bytes we want to reserve
4159  * @force - force the commit
4160  *
4161  * This will check to make sure that committing the transaction will actually
4162  * get us somewhere and then commit the transaction if it does.  Otherwise it
4163  * will return -ENOSPC.
4164  */
4165 static int may_commit_transaction(struct btrfs_root *root,
4166                                   struct btrfs_space_info *space_info,
4167                                   u64 bytes, int force)
4168 {
4169         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4170         struct btrfs_trans_handle *trans;
4171
4172         trans = (struct btrfs_trans_handle *)current->journal_info;
4173         if (trans)
4174                 return -EAGAIN;
4175
4176         if (force)
4177                 goto commit;
4178
4179         /* See if there is enough pinned space to make this reservation */
4180         spin_lock(&space_info->lock);
4181         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4182                                    bytes) >= 0) {
4183                 spin_unlock(&space_info->lock);
4184                 goto commit;
4185         }
4186         spin_unlock(&space_info->lock);
4187
4188         /*
4189          * See if there is some space in the delayed insertion reservation for
4190          * this reservation.
4191          */
4192         if (space_info != delayed_rsv->space_info)
4193                 return -ENOSPC;
4194
4195         spin_lock(&space_info->lock);
4196         spin_lock(&delayed_rsv->lock);
4197         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4198                                    bytes - delayed_rsv->size) >= 0) {
4199                 spin_unlock(&delayed_rsv->lock);
4200                 spin_unlock(&space_info->lock);
4201                 return -ENOSPC;
4202         }
4203         spin_unlock(&delayed_rsv->lock);
4204         spin_unlock(&space_info->lock);
4205
4206 commit:
4207         trans = btrfs_join_transaction(root);
4208         if (IS_ERR(trans))
4209                 return -ENOSPC;
4210
4211         return btrfs_commit_transaction(trans, root);
4212 }
4213
4214 enum flush_state {
4215         FLUSH_DELAYED_ITEMS_NR  =       1,
4216         FLUSH_DELAYED_ITEMS     =       2,
4217         FLUSH_DELALLOC          =       3,
4218         FLUSH_DELALLOC_WAIT     =       4,
4219         ALLOC_CHUNK             =       5,
4220         COMMIT_TRANS            =       6,
4221 };
4222
4223 static int flush_space(struct btrfs_root *root,
4224                        struct btrfs_space_info *space_info, u64 num_bytes,
4225                        u64 orig_bytes, int state)
4226 {
4227         struct btrfs_trans_handle *trans;
4228         int nr;
4229         int ret = 0;
4230
4231         switch (state) {
4232         case FLUSH_DELAYED_ITEMS_NR:
4233         case FLUSH_DELAYED_ITEMS:
4234                 if (state == FLUSH_DELAYED_ITEMS_NR)
4235                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4236                 else
4237                         nr = -1;
4238
4239                 trans = btrfs_join_transaction(root);
4240                 if (IS_ERR(trans)) {
4241                         ret = PTR_ERR(trans);
4242                         break;
4243                 }
4244                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4245                 btrfs_end_transaction(trans, root);
4246                 break;
4247         case FLUSH_DELALLOC:
4248         case FLUSH_DELALLOC_WAIT:
4249                 shrink_delalloc(root, num_bytes, orig_bytes,
4250                                 state == FLUSH_DELALLOC_WAIT);
4251                 break;
4252         case ALLOC_CHUNK:
4253                 trans = btrfs_join_transaction(root);
4254                 if (IS_ERR(trans)) {
4255                         ret = PTR_ERR(trans);
4256                         break;
4257                 }
4258                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4259                                      btrfs_get_alloc_profile(root, 0),
4260                                      CHUNK_ALLOC_NO_FORCE);
4261                 btrfs_end_transaction(trans, root);
4262                 if (ret == -ENOSPC)
4263                         ret = 0;
4264                 break;
4265         case COMMIT_TRANS:
4266                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4267                 break;
4268         default:
4269                 ret = -ENOSPC;
4270                 break;
4271         }
4272
4273         return ret;
4274 }
4275 /**
4276  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4277  * @root - the root we're allocating for
4278  * @block_rsv - the block_rsv we're allocating for
4279  * @orig_bytes - the number of bytes we want
4280  * @flush - whether or not we can flush to make our reservation
4281  *
4282  * This will reserve orgi_bytes number of bytes from the space info associated
4283  * with the block_rsv.  If there is not enough space it will make an attempt to
4284  * flush out space to make room.  It will do this by flushing delalloc if
4285  * possible or committing the transaction.  If flush is 0 then no attempts to
4286  * regain reservations will be made and this will fail if there is not enough
4287  * space already.
4288  */
4289 static int reserve_metadata_bytes(struct btrfs_root *root,
4290                                   struct btrfs_block_rsv *block_rsv,
4291                                   u64 orig_bytes,
4292                                   enum btrfs_reserve_flush_enum flush)
4293 {
4294         struct btrfs_space_info *space_info = block_rsv->space_info;
4295         u64 used;
4296         u64 num_bytes = orig_bytes;
4297         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4298         int ret = 0;
4299         bool flushing = false;
4300
4301 again:
4302         ret = 0;
4303         spin_lock(&space_info->lock);
4304         /*
4305          * We only want to wait if somebody other than us is flushing and we
4306          * are actually allowed to flush all things.
4307          */
4308         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4309                space_info->flush) {
4310                 spin_unlock(&space_info->lock);
4311                 /*
4312                  * If we have a trans handle we can't wait because the flusher
4313                  * may have to commit the transaction, which would mean we would
4314                  * deadlock since we are waiting for the flusher to finish, but
4315                  * hold the current transaction open.
4316                  */
4317                 if (current->journal_info)
4318                         return -EAGAIN;
4319                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4320                 /* Must have been killed, return */
4321                 if (ret)
4322                         return -EINTR;
4323
4324                 spin_lock(&space_info->lock);
4325         }
4326
4327         ret = -ENOSPC;
4328         used = space_info->bytes_used + space_info->bytes_reserved +
4329                 space_info->bytes_pinned + space_info->bytes_readonly +
4330                 space_info->bytes_may_use;
4331
4332         /*
4333          * The idea here is that we've not already over-reserved the block group
4334          * then we can go ahead and save our reservation first and then start
4335          * flushing if we need to.  Otherwise if we've already overcommitted
4336          * lets start flushing stuff first and then come back and try to make
4337          * our reservation.
4338          */
4339         if (used <= space_info->total_bytes) {
4340                 if (used + orig_bytes <= space_info->total_bytes) {
4341                         space_info->bytes_may_use += orig_bytes;
4342                         trace_btrfs_space_reservation(root->fs_info,
4343                                 "space_info", space_info->flags, orig_bytes, 1);
4344                         ret = 0;
4345                 } else {
4346                         /*
4347                          * Ok set num_bytes to orig_bytes since we aren't
4348                          * overocmmitted, this way we only try and reclaim what
4349                          * we need.
4350                          */
4351                         num_bytes = orig_bytes;
4352                 }
4353         } else {
4354                 /*
4355                  * Ok we're over committed, set num_bytes to the overcommitted
4356                  * amount plus the amount of bytes that we need for this
4357                  * reservation.
4358                  */
4359                 num_bytes = used - space_info->total_bytes +
4360                         (orig_bytes * 2);
4361         }
4362
4363         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4364                 space_info->bytes_may_use += orig_bytes;
4365                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4366                                               space_info->flags, orig_bytes,
4367                                               1);
4368                 ret = 0;
4369         }
4370
4371         /*
4372          * Couldn't make our reservation, save our place so while we're trying
4373          * to reclaim space we can actually use it instead of somebody else
4374          * stealing it from us.
4375          *
4376          * We make the other tasks wait for the flush only when we can flush
4377          * all things.
4378          */
4379         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4380                 flushing = true;
4381                 space_info->flush = 1;
4382         }
4383
4384         spin_unlock(&space_info->lock);
4385
4386         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4387                 goto out;
4388
4389         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4390                           flush_state);
4391         flush_state++;
4392
4393         /*
4394          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4395          * would happen. So skip delalloc flush.
4396          */
4397         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4398             (flush_state == FLUSH_DELALLOC ||
4399              flush_state == FLUSH_DELALLOC_WAIT))
4400                 flush_state = ALLOC_CHUNK;
4401
4402         if (!ret)
4403                 goto again;
4404         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4405                  flush_state < COMMIT_TRANS)
4406                 goto again;
4407         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4408                  flush_state <= COMMIT_TRANS)
4409                 goto again;
4410
4411 out:
4412         if (ret == -ENOSPC &&
4413             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4414                 struct btrfs_block_rsv *global_rsv =
4415                         &root->fs_info->global_block_rsv;
4416
4417                 if (block_rsv != global_rsv &&
4418                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4419                         ret = 0;
4420         }
4421         if (ret == -ENOSPC)
4422                 trace_btrfs_space_reservation(root->fs_info,
4423                                               "space_info:enospc",
4424                                               space_info->flags, orig_bytes, 1);
4425         if (flushing) {
4426                 spin_lock(&space_info->lock);
4427                 space_info->flush = 0;
4428                 wake_up_all(&space_info->wait);
4429                 spin_unlock(&space_info->lock);
4430         }
4431         return ret;
4432 }
4433
4434 static struct btrfs_block_rsv *get_block_rsv(
4435                                         const struct btrfs_trans_handle *trans,
4436                                         const struct btrfs_root *root)
4437 {
4438         struct btrfs_block_rsv *block_rsv = NULL;
4439
4440         if (root->ref_cows)
4441                 block_rsv = trans->block_rsv;
4442
4443         if (root == root->fs_info->csum_root && trans->adding_csums)
4444                 block_rsv = trans->block_rsv;
4445
4446         if (root == root->fs_info->uuid_root)
4447                 block_rsv = trans->block_rsv;
4448
4449         if (!block_rsv)
4450                 block_rsv = root->block_rsv;
4451
4452         if (!block_rsv)
4453                 block_rsv = &root->fs_info->empty_block_rsv;
4454
4455         return block_rsv;
4456 }
4457
4458 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4459                                u64 num_bytes)
4460 {
4461         int ret = -ENOSPC;
4462         spin_lock(&block_rsv->lock);
4463         if (block_rsv->reserved >= num_bytes) {
4464                 block_rsv->reserved -= num_bytes;
4465                 if (block_rsv->reserved < block_rsv->size)
4466                         block_rsv->full = 0;
4467                 ret = 0;
4468         }
4469         spin_unlock(&block_rsv->lock);
4470         return ret;
4471 }
4472
4473 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4474                                 u64 num_bytes, int update_size)
4475 {
4476         spin_lock(&block_rsv->lock);
4477         block_rsv->reserved += num_bytes;
4478         if (update_size)
4479                 block_rsv->size += num_bytes;
4480         else if (block_rsv->reserved >= block_rsv->size)
4481                 block_rsv->full = 1;
4482         spin_unlock(&block_rsv->lock);
4483 }
4484
4485 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4486                              struct btrfs_block_rsv *dest, u64 num_bytes,
4487                              int min_factor)
4488 {
4489         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4490         u64 min_bytes;
4491
4492         if (global_rsv->space_info != dest->space_info)
4493                 return -ENOSPC;
4494
4495         spin_lock(&global_rsv->lock);
4496         min_bytes = div_factor(global_rsv->size, min_factor);
4497         if (global_rsv->reserved < min_bytes + num_bytes) {
4498                 spin_unlock(&global_rsv->lock);
4499                 return -ENOSPC;
4500         }
4501         global_rsv->reserved -= num_bytes;
4502         if (global_rsv->reserved < global_rsv->size)
4503                 global_rsv->full = 0;
4504         spin_unlock(&global_rsv->lock);
4505
4506         block_rsv_add_bytes(dest, num_bytes, 1);
4507         return 0;
4508 }
4509
4510 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4511                                     struct btrfs_block_rsv *block_rsv,
4512                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4513 {
4514         struct btrfs_space_info *space_info = block_rsv->space_info;
4515
4516         spin_lock(&block_rsv->lock);
4517         if (num_bytes == (u64)-1)
4518                 num_bytes = block_rsv->size;
4519         block_rsv->size -= num_bytes;
4520         if (block_rsv->reserved >= block_rsv->size) {
4521                 num_bytes = block_rsv->reserved - block_rsv->size;
4522                 block_rsv->reserved = block_rsv->size;
4523                 block_rsv->full = 1;
4524         } else {
4525                 num_bytes = 0;
4526         }
4527         spin_unlock(&block_rsv->lock);
4528
4529         if (num_bytes > 0) {
4530                 if (dest) {
4531                         spin_lock(&dest->lock);
4532                         if (!dest->full) {
4533                                 u64 bytes_to_add;
4534
4535                                 bytes_to_add = dest->size - dest->reserved;
4536                                 bytes_to_add = min(num_bytes, bytes_to_add);
4537                                 dest->reserved += bytes_to_add;
4538                                 if (dest->reserved >= dest->size)
4539                                         dest->full = 1;
4540                                 num_bytes -= bytes_to_add;
4541                         }
4542                         spin_unlock(&dest->lock);
4543                 }
4544                 if (num_bytes) {
4545                         spin_lock(&space_info->lock);
4546                         space_info->bytes_may_use -= num_bytes;
4547                         trace_btrfs_space_reservation(fs_info, "space_info",
4548                                         space_info->flags, num_bytes, 0);
4549                         spin_unlock(&space_info->lock);
4550                 }
4551         }
4552 }
4553
4554 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4555                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4556 {
4557         int ret;
4558
4559         ret = block_rsv_use_bytes(src, num_bytes);
4560         if (ret)
4561                 return ret;
4562
4563         block_rsv_add_bytes(dst, num_bytes, 1);
4564         return 0;
4565 }
4566
4567 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4568 {
4569         memset(rsv, 0, sizeof(*rsv));
4570         spin_lock_init(&rsv->lock);
4571         rsv->type = type;
4572 }
4573
4574 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4575                                               unsigned short type)
4576 {
4577         struct btrfs_block_rsv *block_rsv;
4578         struct btrfs_fs_info *fs_info = root->fs_info;
4579
4580         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4581         if (!block_rsv)
4582                 return NULL;
4583
4584         btrfs_init_block_rsv(block_rsv, type);
4585         block_rsv->space_info = __find_space_info(fs_info,
4586                                                   BTRFS_BLOCK_GROUP_METADATA);
4587         return block_rsv;
4588 }
4589
4590 void btrfs_free_block_rsv(struct btrfs_root *root,
4591                           struct btrfs_block_rsv *rsv)
4592 {
4593         if (!rsv)
4594                 return;
4595         btrfs_block_rsv_release(root, rsv, (u64)-1);
4596         kfree(rsv);
4597 }
4598
4599 int btrfs_block_rsv_add(struct btrfs_root *root,
4600                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4601                         enum btrfs_reserve_flush_enum flush)
4602 {
4603         int ret;
4604
4605         if (num_bytes == 0)
4606                 return 0;
4607
4608         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4609         if (!ret) {
4610                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4611                 return 0;
4612         }
4613
4614         return ret;
4615 }
4616
4617 int btrfs_block_rsv_check(struct btrfs_root *root,
4618                           struct btrfs_block_rsv *block_rsv, int min_factor)
4619 {
4620         u64 num_bytes = 0;
4621         int ret = -ENOSPC;
4622
4623         if (!block_rsv)
4624                 return 0;
4625
4626         spin_lock(&block_rsv->lock);
4627         num_bytes = div_factor(block_rsv->size, min_factor);
4628         if (block_rsv->reserved >= num_bytes)
4629                 ret = 0;
4630         spin_unlock(&block_rsv->lock);
4631
4632         return ret;
4633 }
4634
4635 int btrfs_block_rsv_refill(struct btrfs_root *root,
4636                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4637                            enum btrfs_reserve_flush_enum flush)
4638 {
4639         u64 num_bytes = 0;
4640         int ret = -ENOSPC;
4641
4642         if (!block_rsv)
4643                 return 0;
4644
4645         spin_lock(&block_rsv->lock);
4646         num_bytes = min_reserved;
4647         if (block_rsv->reserved >= num_bytes)
4648                 ret = 0;
4649         else
4650                 num_bytes -= block_rsv->reserved;
4651         spin_unlock(&block_rsv->lock);
4652
4653         if (!ret)
4654                 return 0;
4655
4656         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4657         if (!ret) {
4658                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4659                 return 0;
4660         }
4661
4662         return ret;
4663 }
4664
4665 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4666                             struct btrfs_block_rsv *dst_rsv,
4667                             u64 num_bytes)
4668 {
4669         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4670 }
4671
4672 void btrfs_block_rsv_release(struct btrfs_root *root,
4673                              struct btrfs_block_rsv *block_rsv,
4674                              u64 num_bytes)
4675 {
4676         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4677         if (global_rsv == block_rsv ||
4678             block_rsv->space_info != global_rsv->space_info)
4679                 global_rsv = NULL;
4680         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4681                                 num_bytes);
4682 }
4683
4684 /*
4685  * helper to calculate size of global block reservation.
4686  * the desired value is sum of space used by extent tree,
4687  * checksum tree and root tree
4688  */
4689 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4690 {
4691         struct btrfs_space_info *sinfo;
4692         u64 num_bytes;
4693         u64 meta_used;
4694         u64 data_used;
4695         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4696
4697         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4698         spin_lock(&sinfo->lock);
4699         data_used = sinfo->bytes_used;
4700         spin_unlock(&sinfo->lock);
4701
4702         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4703         spin_lock(&sinfo->lock);
4704         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4705                 data_used = 0;
4706         meta_used = sinfo->bytes_used;
4707         spin_unlock(&sinfo->lock);
4708
4709         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4710                     csum_size * 2;
4711         num_bytes += div64_u64(data_used + meta_used, 50);
4712
4713         if (num_bytes * 3 > meta_used)
4714                 num_bytes = div64_u64(meta_used, 3);
4715
4716         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4717 }
4718
4719 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4720 {
4721         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4722         struct btrfs_space_info *sinfo = block_rsv->space_info;
4723         u64 num_bytes;
4724
4725         num_bytes = calc_global_metadata_size(fs_info);
4726
4727         spin_lock(&sinfo->lock);
4728         spin_lock(&block_rsv->lock);
4729
4730         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4731
4732         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4733                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4734                     sinfo->bytes_may_use;
4735
4736         if (sinfo->total_bytes > num_bytes) {
4737                 num_bytes = sinfo->total_bytes - num_bytes;
4738                 block_rsv->reserved += num_bytes;
4739                 sinfo->bytes_may_use += num_bytes;
4740                 trace_btrfs_space_reservation(fs_info, "space_info",
4741                                       sinfo->flags, num_bytes, 1);
4742         }
4743
4744         if (block_rsv->reserved >= block_rsv->size) {
4745                 num_bytes = block_rsv->reserved - block_rsv->size;
4746                 sinfo->bytes_may_use -= num_bytes;
4747                 trace_btrfs_space_reservation(fs_info, "space_info",
4748                                       sinfo->flags, num_bytes, 0);
4749                 block_rsv->reserved = block_rsv->size;
4750                 block_rsv->full = 1;
4751         }
4752
4753         spin_unlock(&block_rsv->lock);
4754         spin_unlock(&sinfo->lock);
4755 }
4756
4757 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4758 {
4759         struct btrfs_space_info *space_info;
4760
4761         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4762         fs_info->chunk_block_rsv.space_info = space_info;
4763
4764         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4765         fs_info->global_block_rsv.space_info = space_info;
4766         fs_info->delalloc_block_rsv.space_info = space_info;
4767         fs_info->trans_block_rsv.space_info = space_info;
4768         fs_info->empty_block_rsv.space_info = space_info;
4769         fs_info->delayed_block_rsv.space_info = space_info;
4770
4771         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4772         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4773         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4774         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4775         if (fs_info->quota_root)
4776                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4777         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4778
4779         update_global_block_rsv(fs_info);
4780 }
4781
4782 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4783 {
4784         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4785                                 (u64)-1);
4786         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4787         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4788         WARN_ON(fs_info->trans_block_rsv.size > 0);
4789         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4790         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4791         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4792         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4793         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4794 }
4795
4796 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4797                                   struct btrfs_root *root)
4798 {
4799         if (!trans->block_rsv)
4800                 return;
4801
4802         if (!trans->bytes_reserved)
4803                 return;
4804
4805         trace_btrfs_space_reservation(root->fs_info, "transaction",
4806                                       trans->transid, trans->bytes_reserved, 0);
4807         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4808         trans->bytes_reserved = 0;
4809 }
4810
4811 /* Can only return 0 or -ENOSPC */
4812 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4813                                   struct inode *inode)
4814 {
4815         struct btrfs_root *root = BTRFS_I(inode)->root;
4816         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4817         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4818
4819         /*
4820          * We need to hold space in order to delete our orphan item once we've
4821          * added it, so this takes the reservation so we can release it later
4822          * when we are truly done with the orphan item.
4823          */
4824         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4825         trace_btrfs_space_reservation(root->fs_info, "orphan",
4826                                       btrfs_ino(inode), num_bytes, 1);
4827         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4828 }
4829
4830 void btrfs_orphan_release_metadata(struct inode *inode)
4831 {
4832         struct btrfs_root *root = BTRFS_I(inode)->root;
4833         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4834         trace_btrfs_space_reservation(root->fs_info, "orphan",
4835                                       btrfs_ino(inode), num_bytes, 0);
4836         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4837 }
4838
4839 /*
4840  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4841  * root: the root of the parent directory
4842  * rsv: block reservation
4843  * items: the number of items that we need do reservation
4844  * qgroup_reserved: used to return the reserved size in qgroup
4845  *
4846  * This function is used to reserve the space for snapshot/subvolume
4847  * creation and deletion. Those operations are different with the
4848  * common file/directory operations, they change two fs/file trees
4849  * and root tree, the number of items that the qgroup reserves is
4850  * different with the free space reservation. So we can not use
4851  * the space reseravtion mechanism in start_transaction().
4852  */
4853 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4854                                      struct btrfs_block_rsv *rsv,
4855                                      int items,
4856                                      u64 *qgroup_reserved,
4857                                      bool use_global_rsv)
4858 {
4859         u64 num_bytes;
4860         int ret;
4861         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4862
4863         if (root->fs_info->quota_enabled) {
4864                 /* One for parent inode, two for dir entries */
4865                 num_bytes = 3 * root->leafsize;
4866                 ret = btrfs_qgroup_reserve(root, num_bytes);
4867                 if (ret)
4868                         return ret;
4869         } else {
4870                 num_bytes = 0;
4871         }
4872
4873         *qgroup_reserved = num_bytes;
4874
4875         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4876         rsv->space_info = __find_space_info(root->fs_info,
4877                                             BTRFS_BLOCK_GROUP_METADATA);
4878         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4879                                   BTRFS_RESERVE_FLUSH_ALL);
4880
4881         if (ret == -ENOSPC && use_global_rsv)
4882                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4883
4884         if (ret) {
4885                 if (*qgroup_reserved)
4886                         btrfs_qgroup_free(root, *qgroup_reserved);
4887         }
4888
4889         return ret;
4890 }
4891
4892 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4893                                       struct btrfs_block_rsv *rsv,
4894                                       u64 qgroup_reserved)
4895 {
4896         btrfs_block_rsv_release(root, rsv, (u64)-1);
4897         if (qgroup_reserved)
4898                 btrfs_qgroup_free(root, qgroup_reserved);
4899 }
4900
4901 /**
4902  * drop_outstanding_extent - drop an outstanding extent
4903  * @inode: the inode we're dropping the extent for
4904  *
4905  * This is called when we are freeing up an outstanding extent, either called
4906  * after an error or after an extent is written.  This will return the number of
4907  * reserved extents that need to be freed.  This must be called with
4908  * BTRFS_I(inode)->lock held.
4909  */
4910 static unsigned drop_outstanding_extent(struct inode *inode)
4911 {
4912         unsigned drop_inode_space = 0;
4913         unsigned dropped_extents = 0;
4914
4915         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4916         BTRFS_I(inode)->outstanding_extents--;
4917
4918         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4919             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4920                                &BTRFS_I(inode)->runtime_flags))
4921                 drop_inode_space = 1;
4922
4923         /*
4924          * If we have more or the same amount of outsanding extents than we have
4925          * reserved then we need to leave the reserved extents count alone.
4926          */
4927         if (BTRFS_I(inode)->outstanding_extents >=
4928             BTRFS_I(inode)->reserved_extents)
4929                 return drop_inode_space;
4930
4931         dropped_extents = BTRFS_I(inode)->reserved_extents -
4932                 BTRFS_I(inode)->outstanding_extents;
4933         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4934         return dropped_extents + drop_inode_space;
4935 }
4936
4937 /**
4938  * calc_csum_metadata_size - return the amount of metada space that must be
4939  *      reserved/free'd for the given bytes.
4940  * @inode: the inode we're manipulating
4941  * @num_bytes: the number of bytes in question
4942  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4943  *
4944  * This adjusts the number of csum_bytes in the inode and then returns the
4945  * correct amount of metadata that must either be reserved or freed.  We
4946  * calculate how many checksums we can fit into one leaf and then divide the
4947  * number of bytes that will need to be checksumed by this value to figure out
4948  * how many checksums will be required.  If we are adding bytes then the number
4949  * may go up and we will return the number of additional bytes that must be
4950  * reserved.  If it is going down we will return the number of bytes that must
4951  * be freed.
4952  *
4953  * This must be called with BTRFS_I(inode)->lock held.
4954  */
4955 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4956                                    int reserve)
4957 {
4958         struct btrfs_root *root = BTRFS_I(inode)->root;
4959         u64 csum_size;
4960         int num_csums_per_leaf;
4961         int num_csums;
4962         int old_csums;
4963
4964         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4965             BTRFS_I(inode)->csum_bytes == 0)
4966                 return 0;
4967
4968         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4969         if (reserve)
4970                 BTRFS_I(inode)->csum_bytes += num_bytes;
4971         else
4972                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4973         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4974         num_csums_per_leaf = (int)div64_u64(csum_size,
4975                                             sizeof(struct btrfs_csum_item) +
4976                                             sizeof(struct btrfs_disk_key));
4977         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4978         num_csums = num_csums + num_csums_per_leaf - 1;
4979         num_csums = num_csums / num_csums_per_leaf;
4980
4981         old_csums = old_csums + num_csums_per_leaf - 1;
4982         old_csums = old_csums / num_csums_per_leaf;
4983
4984         /* No change, no need to reserve more */
4985         if (old_csums == num_csums)
4986                 return 0;
4987
4988         if (reserve)
4989                 return btrfs_calc_trans_metadata_size(root,
4990                                                       num_csums - old_csums);
4991
4992         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4993 }
4994
4995 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4996 {
4997         struct btrfs_root *root = BTRFS_I(inode)->root;
4998         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4999         u64 to_reserve = 0;
5000         u64 csum_bytes;
5001         unsigned nr_extents = 0;
5002         int extra_reserve = 0;
5003         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5004         int ret = 0;
5005         bool delalloc_lock = true;
5006         u64 to_free = 0;
5007         unsigned dropped;
5008
5009         /* If we are a free space inode we need to not flush since we will be in
5010          * the middle of a transaction commit.  We also don't need the delalloc
5011          * mutex since we won't race with anybody.  We need this mostly to make
5012          * lockdep shut its filthy mouth.
5013          */
5014         if (btrfs_is_free_space_inode(inode)) {
5015                 flush = BTRFS_RESERVE_NO_FLUSH;
5016                 delalloc_lock = false;
5017         }
5018
5019         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5020             btrfs_transaction_in_commit(root->fs_info))
5021                 schedule_timeout(1);
5022
5023         if (delalloc_lock)
5024                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5025
5026         num_bytes = ALIGN(num_bytes, root->sectorsize);
5027
5028         spin_lock(&BTRFS_I(inode)->lock);
5029         BTRFS_I(inode)->outstanding_extents++;
5030
5031         if (BTRFS_I(inode)->outstanding_extents >
5032             BTRFS_I(inode)->reserved_extents)
5033                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5034                         BTRFS_I(inode)->reserved_extents;
5035
5036         /*
5037          * Add an item to reserve for updating the inode when we complete the
5038          * delalloc io.
5039          */
5040         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5041                       &BTRFS_I(inode)->runtime_flags)) {
5042                 nr_extents++;
5043                 extra_reserve = 1;
5044         }
5045
5046         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5047         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5048         csum_bytes = BTRFS_I(inode)->csum_bytes;
5049         spin_unlock(&BTRFS_I(inode)->lock);
5050
5051         if (root->fs_info->quota_enabled) {
5052                 ret = btrfs_qgroup_reserve(root, num_bytes +
5053                                            nr_extents * root->leafsize);
5054                 if (ret)
5055                         goto out_fail;
5056         }
5057
5058         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5059         if (unlikely(ret)) {
5060                 if (root->fs_info->quota_enabled)
5061                         btrfs_qgroup_free(root, num_bytes +
5062                                                 nr_extents * root->leafsize);
5063                 goto out_fail;
5064         }
5065
5066         spin_lock(&BTRFS_I(inode)->lock);
5067         if (extra_reserve) {
5068                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5069                         &BTRFS_I(inode)->runtime_flags);
5070                 nr_extents--;
5071         }
5072         BTRFS_I(inode)->reserved_extents += nr_extents;
5073         spin_unlock(&BTRFS_I(inode)->lock);
5074
5075         if (delalloc_lock)
5076                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5077
5078         if (to_reserve)
5079                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5080                                               btrfs_ino(inode), to_reserve, 1);
5081         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5082
5083         return 0;
5084
5085 out_fail:
5086         spin_lock(&BTRFS_I(inode)->lock);
5087         dropped = drop_outstanding_extent(inode);
5088         /*
5089          * If the inodes csum_bytes is the same as the original
5090          * csum_bytes then we know we haven't raced with any free()ers
5091          * so we can just reduce our inodes csum bytes and carry on.
5092          */
5093         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5094                 calc_csum_metadata_size(inode, num_bytes, 0);
5095         } else {
5096                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5097                 u64 bytes;
5098
5099                 /*
5100                  * This is tricky, but first we need to figure out how much we
5101                  * free'd from any free-ers that occured during this
5102                  * reservation, so we reset ->csum_bytes to the csum_bytes
5103                  * before we dropped our lock, and then call the free for the
5104                  * number of bytes that were freed while we were trying our
5105                  * reservation.
5106                  */
5107                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5108                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5109                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5110
5111
5112                 /*
5113                  * Now we need to see how much we would have freed had we not
5114                  * been making this reservation and our ->csum_bytes were not
5115                  * artificially inflated.
5116                  */
5117                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5118                 bytes = csum_bytes - orig_csum_bytes;
5119                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5120
5121                 /*
5122                  * Now reset ->csum_bytes to what it should be.  If bytes is
5123                  * more than to_free then we would have free'd more space had we
5124                  * not had an artificially high ->csum_bytes, so we need to free
5125                  * the remainder.  If bytes is the same or less then we don't
5126                  * need to do anything, the other free-ers did the correct
5127                  * thing.
5128                  */
5129                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5130                 if (bytes > to_free)
5131                         to_free = bytes - to_free;
5132                 else
5133                         to_free = 0;
5134         }
5135         spin_unlock(&BTRFS_I(inode)->lock);
5136         if (dropped)
5137                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5138
5139         if (to_free) {
5140                 btrfs_block_rsv_release(root, block_rsv, to_free);
5141                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5142                                               btrfs_ino(inode), to_free, 0);
5143         }
5144         if (delalloc_lock)
5145                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5146         return ret;
5147 }
5148
5149 /**
5150  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5151  * @inode: the inode to release the reservation for
5152  * @num_bytes: the number of bytes we're releasing
5153  *
5154  * This will release the metadata reservation for an inode.  This can be called
5155  * once we complete IO for a given set of bytes to release their metadata
5156  * reservations.
5157  */
5158 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5159 {
5160         struct btrfs_root *root = BTRFS_I(inode)->root;
5161         u64 to_free = 0;
5162         unsigned dropped;
5163
5164         num_bytes = ALIGN(num_bytes, root->sectorsize);
5165         spin_lock(&BTRFS_I(inode)->lock);
5166         dropped = drop_outstanding_extent(inode);
5167
5168         if (num_bytes)
5169                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5170         spin_unlock(&BTRFS_I(inode)->lock);
5171         if (dropped > 0)
5172                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5173
5174         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5175                                       btrfs_ino(inode), to_free, 0);
5176         if (root->fs_info->quota_enabled) {
5177                 btrfs_qgroup_free(root, num_bytes +
5178                                         dropped * root->leafsize);
5179         }
5180
5181         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5182                                 to_free);
5183 }
5184
5185 /**
5186  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5187  * @inode: inode we're writing to
5188  * @num_bytes: the number of bytes we want to allocate
5189  *
5190  * This will do the following things
5191  *
5192  * o reserve space in the data space info for num_bytes
5193  * o reserve space in the metadata space info based on number of outstanding
5194  *   extents and how much csums will be needed
5195  * o add to the inodes ->delalloc_bytes
5196  * o add it to the fs_info's delalloc inodes list.
5197  *
5198  * This will return 0 for success and -ENOSPC if there is no space left.
5199  */
5200 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5201 {
5202         int ret;
5203
5204         ret = btrfs_check_data_free_space(inode, num_bytes);
5205         if (ret)
5206                 return ret;
5207
5208         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5209         if (ret) {
5210                 btrfs_free_reserved_data_space(inode, num_bytes);
5211                 return ret;
5212         }
5213
5214         return 0;
5215 }
5216
5217 /**
5218  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5219  * @inode: inode we're releasing space for
5220  * @num_bytes: the number of bytes we want to free up
5221  *
5222  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5223  * called in the case that we don't need the metadata AND data reservations
5224  * anymore.  So if there is an error or we insert an inline extent.
5225  *
5226  * This function will release the metadata space that was not used and will
5227  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5228  * list if there are no delalloc bytes left.
5229  */
5230 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5231 {
5232         btrfs_delalloc_release_metadata(inode, num_bytes);
5233         btrfs_free_reserved_data_space(inode, num_bytes);
5234 }
5235
5236 static int update_block_group(struct btrfs_root *root,
5237                               u64 bytenr, u64 num_bytes, int alloc)
5238 {
5239         struct btrfs_block_group_cache *cache = NULL;
5240         struct btrfs_fs_info *info = root->fs_info;
5241         u64 total = num_bytes;
5242         u64 old_val;
5243         u64 byte_in_group;
5244         int factor;
5245
5246         /* block accounting for super block */
5247         spin_lock(&info->delalloc_root_lock);
5248         old_val = btrfs_super_bytes_used(info->super_copy);
5249         if (alloc)
5250                 old_val += num_bytes;
5251         else
5252                 old_val -= num_bytes;
5253         btrfs_set_super_bytes_used(info->super_copy, old_val);
5254         spin_unlock(&info->delalloc_root_lock);
5255
5256         while (total) {
5257                 cache = btrfs_lookup_block_group(info, bytenr);
5258                 if (!cache)
5259                         return -ENOENT;
5260                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5261                                     BTRFS_BLOCK_GROUP_RAID1 |
5262                                     BTRFS_BLOCK_GROUP_RAID10))
5263                         factor = 2;
5264                 else
5265                         factor = 1;
5266                 /*
5267                  * If this block group has free space cache written out, we
5268                  * need to make sure to load it if we are removing space.  This
5269                  * is because we need the unpinning stage to actually add the
5270                  * space back to the block group, otherwise we will leak space.
5271                  */
5272                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5273                         cache_block_group(cache, 1);
5274
5275                 byte_in_group = bytenr - cache->key.objectid;
5276                 WARN_ON(byte_in_group > cache->key.offset);
5277
5278                 spin_lock(&cache->space_info->lock);
5279                 spin_lock(&cache->lock);
5280
5281                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5282                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5283                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5284
5285                 cache->dirty = 1;
5286                 old_val = btrfs_block_group_used(&cache->item);
5287                 num_bytes = min(total, cache->key.offset - byte_in_group);
5288                 if (alloc) {
5289                         old_val += num_bytes;
5290                         btrfs_set_block_group_used(&cache->item, old_val);
5291                         cache->reserved -= num_bytes;
5292                         cache->space_info->bytes_reserved -= num_bytes;
5293                         cache->space_info->bytes_used += num_bytes;
5294                         cache->space_info->disk_used += num_bytes * factor;
5295                         spin_unlock(&cache->lock);
5296                         spin_unlock(&cache->space_info->lock);
5297                 } else {
5298                         old_val -= num_bytes;
5299                         btrfs_set_block_group_used(&cache->item, old_val);
5300                         cache->pinned += num_bytes;
5301                         cache->space_info->bytes_pinned += num_bytes;
5302                         cache->space_info->bytes_used -= num_bytes;
5303                         cache->space_info->disk_used -= num_bytes * factor;
5304                         spin_unlock(&cache->lock);
5305                         spin_unlock(&cache->space_info->lock);
5306
5307                         set_extent_dirty(info->pinned_extents,
5308                                          bytenr, bytenr + num_bytes - 1,
5309                                          GFP_NOFS | __GFP_NOFAIL);
5310                 }
5311                 btrfs_put_block_group(cache);
5312                 total -= num_bytes;
5313                 bytenr += num_bytes;
5314         }
5315         return 0;
5316 }
5317
5318 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5319 {
5320         struct btrfs_block_group_cache *cache;
5321         u64 bytenr;
5322
5323         spin_lock(&root->fs_info->block_group_cache_lock);
5324         bytenr = root->fs_info->first_logical_byte;
5325         spin_unlock(&root->fs_info->block_group_cache_lock);
5326
5327         if (bytenr < (u64)-1)
5328                 return bytenr;
5329
5330         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5331         if (!cache)
5332                 return 0;
5333
5334         bytenr = cache->key.objectid;
5335         btrfs_put_block_group(cache);
5336
5337         return bytenr;
5338 }
5339
5340 static int pin_down_extent(struct btrfs_root *root,
5341                            struct btrfs_block_group_cache *cache,
5342                            u64 bytenr, u64 num_bytes, int reserved)
5343 {
5344         spin_lock(&cache->space_info->lock);
5345         spin_lock(&cache->lock);
5346         cache->pinned += num_bytes;
5347         cache->space_info->bytes_pinned += num_bytes;
5348         if (reserved) {
5349                 cache->reserved -= num_bytes;
5350                 cache->space_info->bytes_reserved -= num_bytes;
5351         }
5352         spin_unlock(&cache->lock);
5353         spin_unlock(&cache->space_info->lock);
5354
5355         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5356                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5357         if (reserved)
5358                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5359         return 0;
5360 }
5361
5362 /*
5363  * this function must be called within transaction
5364  */
5365 int btrfs_pin_extent(struct btrfs_root *root,
5366                      u64 bytenr, u64 num_bytes, int reserved)
5367 {
5368         struct btrfs_block_group_cache *cache;
5369
5370         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5371         BUG_ON(!cache); /* Logic error */
5372
5373         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5374
5375         btrfs_put_block_group(cache);
5376         return 0;
5377 }
5378
5379 /*
5380  * this function must be called within transaction
5381  */
5382 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5383                                     u64 bytenr, u64 num_bytes)
5384 {
5385         struct btrfs_block_group_cache *cache;
5386         int ret;
5387
5388         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5389         if (!cache)
5390                 return -EINVAL;
5391
5392         /*
5393          * pull in the free space cache (if any) so that our pin
5394          * removes the free space from the cache.  We have load_only set
5395          * to one because the slow code to read in the free extents does check
5396          * the pinned extents.
5397          */
5398         cache_block_group(cache, 1);
5399
5400         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5401
5402         /* remove us from the free space cache (if we're there at all) */
5403         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5404         btrfs_put_block_group(cache);
5405         return ret;
5406 }
5407
5408 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5409 {
5410         int ret;
5411         struct btrfs_block_group_cache *block_group;
5412         struct btrfs_caching_control *caching_ctl;
5413
5414         block_group = btrfs_lookup_block_group(root->fs_info, start);
5415         if (!block_group)
5416                 return -EINVAL;
5417
5418         cache_block_group(block_group, 0);
5419         caching_ctl = get_caching_control(block_group);
5420
5421         if (!caching_ctl) {
5422                 /* Logic error */
5423                 BUG_ON(!block_group_cache_done(block_group));
5424                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5425         } else {
5426                 mutex_lock(&caching_ctl->mutex);
5427
5428                 if (start >= caching_ctl->progress) {
5429                         ret = add_excluded_extent(root, start, num_bytes);
5430                 } else if (start + num_bytes <= caching_ctl->progress) {
5431                         ret = btrfs_remove_free_space(block_group,
5432                                                       start, num_bytes);
5433                 } else {
5434                         num_bytes = caching_ctl->progress - start;
5435                         ret = btrfs_remove_free_space(block_group,
5436                                                       start, num_bytes);
5437                         if (ret)
5438                                 goto out_lock;
5439
5440                         num_bytes = (start + num_bytes) -
5441                                 caching_ctl->progress;
5442                         start = caching_ctl->progress;
5443                         ret = add_excluded_extent(root, start, num_bytes);
5444                 }
5445 out_lock:
5446                 mutex_unlock(&caching_ctl->mutex);
5447                 put_caching_control(caching_ctl);
5448         }
5449         btrfs_put_block_group(block_group);
5450         return ret;
5451 }
5452
5453 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5454                                  struct extent_buffer *eb)
5455 {
5456         struct btrfs_file_extent_item *item;
5457         struct btrfs_key key;
5458         int found_type;
5459         int i;
5460
5461         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5462                 return 0;
5463
5464         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5465                 btrfs_item_key_to_cpu(eb, &key, i);
5466                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5467                         continue;
5468                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5469                 found_type = btrfs_file_extent_type(eb, item);
5470                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5471                         continue;
5472                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5473                         continue;
5474                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5475                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5476                 __exclude_logged_extent(log, key.objectid, key.offset);
5477         }
5478
5479         return 0;
5480 }
5481
5482 /**
5483  * btrfs_update_reserved_bytes - update the block_group and space info counters
5484  * @cache:      The cache we are manipulating
5485  * @num_bytes:  The number of bytes in question
5486  * @reserve:    One of the reservation enums
5487  *
5488  * This is called by the allocator when it reserves space, or by somebody who is
5489  * freeing space that was never actually used on disk.  For example if you
5490  * reserve some space for a new leaf in transaction A and before transaction A
5491  * commits you free that leaf, you call this with reserve set to 0 in order to
5492  * clear the reservation.
5493  *
5494  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5495  * ENOSPC accounting.  For data we handle the reservation through clearing the
5496  * delalloc bits in the io_tree.  We have to do this since we could end up
5497  * allocating less disk space for the amount of data we have reserved in the
5498  * case of compression.
5499  *
5500  * If this is a reservation and the block group has become read only we cannot
5501  * make the reservation and return -EAGAIN, otherwise this function always
5502  * succeeds.
5503  */
5504 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5505                                        u64 num_bytes, int reserve)
5506 {
5507         struct btrfs_space_info *space_info = cache->space_info;
5508         int ret = 0;
5509
5510         spin_lock(&space_info->lock);
5511         spin_lock(&cache->lock);
5512         if (reserve != RESERVE_FREE) {
5513                 if (cache->ro) {
5514                         ret = -EAGAIN;
5515                 } else {
5516                         cache->reserved += num_bytes;
5517                         space_info->bytes_reserved += num_bytes;
5518                         if (reserve == RESERVE_ALLOC) {
5519                                 trace_btrfs_space_reservation(cache->fs_info,
5520                                                 "space_info", space_info->flags,
5521                                                 num_bytes, 0);
5522                                 space_info->bytes_may_use -= num_bytes;
5523                         }
5524                 }
5525         } else {
5526                 if (cache->ro)
5527                         space_info->bytes_readonly += num_bytes;
5528                 cache->reserved -= num_bytes;
5529                 space_info->bytes_reserved -= num_bytes;
5530         }
5531         spin_unlock(&cache->lock);
5532         spin_unlock(&space_info->lock);
5533         return ret;
5534 }
5535
5536 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5537                                 struct btrfs_root *root)
5538 {
5539         struct btrfs_fs_info *fs_info = root->fs_info;
5540         struct btrfs_caching_control *next;
5541         struct btrfs_caching_control *caching_ctl;
5542         struct btrfs_block_group_cache *cache;
5543         struct btrfs_space_info *space_info;
5544
5545         down_write(&fs_info->extent_commit_sem);
5546
5547         list_for_each_entry_safe(caching_ctl, next,
5548                                  &fs_info->caching_block_groups, list) {
5549                 cache = caching_ctl->block_group;
5550                 if (block_group_cache_done(cache)) {
5551                         cache->last_byte_to_unpin = (u64)-1;
5552                         list_del_init(&caching_ctl->list);
5553                         put_caching_control(caching_ctl);
5554                 } else {
5555                         cache->last_byte_to_unpin = caching_ctl->progress;
5556                 }
5557         }
5558
5559         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5560                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5561         else
5562                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5563
5564         up_write(&fs_info->extent_commit_sem);
5565
5566         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5567                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5568
5569         update_global_block_rsv(fs_info);
5570 }
5571
5572 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5573 {
5574         struct btrfs_fs_info *fs_info = root->fs_info;
5575         struct btrfs_block_group_cache *cache = NULL;
5576         struct btrfs_space_info *space_info;
5577         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5578         u64 len;
5579         bool readonly;
5580
5581         while (start <= end) {
5582                 readonly = false;
5583                 if (!cache ||
5584                     start >= cache->key.objectid + cache->key.offset) {
5585                         if (cache)
5586                                 btrfs_put_block_group(cache);
5587                         cache = btrfs_lookup_block_group(fs_info, start);
5588                         BUG_ON(!cache); /* Logic error */
5589                 }
5590
5591                 len = cache->key.objectid + cache->key.offset - start;
5592                 len = min(len, end + 1 - start);
5593
5594                 if (start < cache->last_byte_to_unpin) {
5595                         len = min(len, cache->last_byte_to_unpin - start);
5596                         btrfs_add_free_space(cache, start, len);
5597                 }
5598
5599                 start += len;
5600                 space_info = cache->space_info;
5601
5602                 spin_lock(&space_info->lock);
5603                 spin_lock(&cache->lock);
5604                 cache->pinned -= len;
5605                 space_info->bytes_pinned -= len;
5606                 if (cache->ro) {
5607                         space_info->bytes_readonly += len;
5608                         readonly = true;
5609                 }
5610                 spin_unlock(&cache->lock);
5611                 if (!readonly && global_rsv->space_info == space_info) {
5612                         spin_lock(&global_rsv->lock);
5613                         if (!global_rsv->full) {
5614                                 len = min(len, global_rsv->size -
5615                                           global_rsv->reserved);
5616                                 global_rsv->reserved += len;
5617                                 space_info->bytes_may_use += len;
5618                                 if (global_rsv->reserved >= global_rsv->size)
5619                                         global_rsv->full = 1;
5620                         }
5621                         spin_unlock(&global_rsv->lock);
5622                 }
5623                 spin_unlock(&space_info->lock);
5624         }
5625
5626         if (cache)
5627                 btrfs_put_block_group(cache);
5628         return 0;
5629 }
5630
5631 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5632                                struct btrfs_root *root)
5633 {
5634         struct btrfs_fs_info *fs_info = root->fs_info;
5635         struct extent_io_tree *unpin;
5636         u64 start;
5637         u64 end;
5638         int ret;
5639
5640         if (trans->aborted)
5641                 return 0;
5642
5643         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5644                 unpin = &fs_info->freed_extents[1];
5645         else
5646                 unpin = &fs_info->freed_extents[0];
5647
5648         while (1) {
5649                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5650                                             EXTENT_DIRTY, NULL);
5651                 if (ret)
5652                         break;
5653
5654                 if (btrfs_test_opt(root, DISCARD))
5655                         ret = btrfs_discard_extent(root, start,
5656                                                    end + 1 - start, NULL);
5657
5658                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5659                 unpin_extent_range(root, start, end);
5660                 cond_resched();
5661         }
5662
5663         return 0;
5664 }
5665
5666 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5667                              u64 owner, u64 root_objectid)
5668 {
5669         struct btrfs_space_info *space_info;
5670         u64 flags;
5671
5672         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5673                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5674                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5675                 else
5676                         flags = BTRFS_BLOCK_GROUP_METADATA;
5677         } else {
5678                 flags = BTRFS_BLOCK_GROUP_DATA;
5679         }
5680
5681         space_info = __find_space_info(fs_info, flags);
5682         BUG_ON(!space_info); /* Logic bug */
5683         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5684 }
5685
5686
5687 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5688                                 struct btrfs_root *root,
5689                                 u64 bytenr, u64 num_bytes, u64 parent,
5690                                 u64 root_objectid, u64 owner_objectid,
5691                                 u64 owner_offset, int refs_to_drop,
5692                                 struct btrfs_delayed_extent_op *extent_op)
5693 {
5694         struct btrfs_key key;
5695         struct btrfs_path *path;
5696         struct btrfs_fs_info *info = root->fs_info;
5697         struct btrfs_root *extent_root = info->extent_root;
5698         struct extent_buffer *leaf;
5699         struct btrfs_extent_item *ei;
5700         struct btrfs_extent_inline_ref *iref;
5701         int ret;
5702         int is_data;
5703         int extent_slot = 0;
5704         int found_extent = 0;
5705         int num_to_del = 1;
5706         u32 item_size;
5707         u64 refs;
5708         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5709                                                  SKINNY_METADATA);
5710
5711         path = btrfs_alloc_path();
5712         if (!path)
5713                 return -ENOMEM;
5714
5715         path->reada = 1;
5716         path->leave_spinning = 1;
5717
5718         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5719         BUG_ON(!is_data && refs_to_drop != 1);
5720
5721         if (is_data)
5722                 skinny_metadata = 0;
5723
5724         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5725                                     bytenr, num_bytes, parent,
5726                                     root_objectid, owner_objectid,
5727                                     owner_offset);
5728         if (ret == 0) {
5729                 extent_slot = path->slots[0];
5730                 while (extent_slot >= 0) {
5731                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5732                                               extent_slot);
5733                         if (key.objectid != bytenr)
5734                                 break;
5735                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5736                             key.offset == num_bytes) {
5737                                 found_extent = 1;
5738                                 break;
5739                         }
5740                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5741                             key.offset == owner_objectid) {
5742                                 found_extent = 1;
5743                                 break;
5744                         }
5745                         if (path->slots[0] - extent_slot > 5)
5746                                 break;
5747                         extent_slot--;
5748                 }
5749 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5750                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5751                 if (found_extent && item_size < sizeof(*ei))
5752                         found_extent = 0;
5753 #endif
5754                 if (!found_extent) {
5755                         BUG_ON(iref);
5756                         ret = remove_extent_backref(trans, extent_root, path,
5757                                                     NULL, refs_to_drop,
5758                                                     is_data);
5759                         if (ret) {
5760                                 btrfs_abort_transaction(trans, extent_root, ret);
5761                                 goto out;
5762                         }
5763                         btrfs_release_path(path);
5764                         path->leave_spinning = 1;
5765
5766                         key.objectid = bytenr;
5767                         key.type = BTRFS_EXTENT_ITEM_KEY;
5768                         key.offset = num_bytes;
5769
5770                         if (!is_data && skinny_metadata) {
5771                                 key.type = BTRFS_METADATA_ITEM_KEY;
5772                                 key.offset = owner_objectid;
5773                         }
5774
5775                         ret = btrfs_search_slot(trans, extent_root,
5776                                                 &key, path, -1, 1);
5777                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5778                                 /*
5779                                  * Couldn't find our skinny metadata item,
5780                                  * see if we have ye olde extent item.
5781                                  */
5782                                 path->slots[0]--;
5783                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5784                                                       path->slots[0]);
5785                                 if (key.objectid == bytenr &&
5786                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5787                                     key.offset == num_bytes)
5788                                         ret = 0;
5789                         }
5790
5791                         if (ret > 0 && skinny_metadata) {
5792                                 skinny_metadata = false;
5793                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5794                                 key.offset = num_bytes;
5795                                 btrfs_release_path(path);
5796                                 ret = btrfs_search_slot(trans, extent_root,
5797                                                         &key, path, -1, 1);
5798                         }
5799
5800                         if (ret) {
5801                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5802                                         ret, bytenr);
5803                                 if (ret > 0)
5804                                         btrfs_print_leaf(extent_root,
5805                                                          path->nodes[0]);
5806                         }
5807                         if (ret < 0) {
5808                                 btrfs_abort_transaction(trans, extent_root, ret);
5809                                 goto out;
5810                         }
5811                         extent_slot = path->slots[0];
5812                 }
5813         } else if (WARN_ON(ret == -ENOENT)) {
5814                 btrfs_print_leaf(extent_root, path->nodes[0]);
5815                 btrfs_err(info,
5816                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5817                         bytenr, parent, root_objectid, owner_objectid,
5818                         owner_offset);
5819         } else {
5820                 btrfs_abort_transaction(trans, extent_root, ret);
5821                 goto out;
5822         }
5823
5824         leaf = path->nodes[0];
5825         item_size = btrfs_item_size_nr(leaf, extent_slot);
5826 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5827         if (item_size < sizeof(*ei)) {
5828                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5829                 ret = convert_extent_item_v0(trans, extent_root, path,
5830                                              owner_objectid, 0);
5831                 if (ret < 0) {
5832                         btrfs_abort_transaction(trans, extent_root, ret);
5833                         goto out;
5834                 }
5835
5836                 btrfs_release_path(path);
5837                 path->leave_spinning = 1;
5838
5839                 key.objectid = bytenr;
5840                 key.type = BTRFS_EXTENT_ITEM_KEY;
5841                 key.offset = num_bytes;
5842
5843                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5844                                         -1, 1);
5845                 if (ret) {
5846                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5847                                 ret, bytenr);
5848                         btrfs_print_leaf(extent_root, path->nodes[0]);
5849                 }
5850                 if (ret < 0) {
5851                         btrfs_abort_transaction(trans, extent_root, ret);
5852                         goto out;
5853                 }
5854
5855                 extent_slot = path->slots[0];
5856                 leaf = path->nodes[0];
5857                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5858         }
5859 #endif
5860         BUG_ON(item_size < sizeof(*ei));
5861         ei = btrfs_item_ptr(leaf, extent_slot,
5862                             struct btrfs_extent_item);
5863         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5864             key.type == BTRFS_EXTENT_ITEM_KEY) {
5865                 struct btrfs_tree_block_info *bi;
5866                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5867                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5868                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5869         }
5870
5871         refs = btrfs_extent_refs(leaf, ei);
5872         if (refs < refs_to_drop) {
5873                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5874                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5875                 ret = -EINVAL;
5876                 btrfs_abort_transaction(trans, extent_root, ret);
5877                 goto out;
5878         }
5879         refs -= refs_to_drop;
5880
5881         if (refs > 0) {
5882                 if (extent_op)
5883                         __run_delayed_extent_op(extent_op, leaf, ei);
5884                 /*
5885                  * In the case of inline back ref, reference count will
5886                  * be updated by remove_extent_backref
5887                  */
5888                 if (iref) {
5889                         BUG_ON(!found_extent);
5890                 } else {
5891                         btrfs_set_extent_refs(leaf, ei, refs);
5892                         btrfs_mark_buffer_dirty(leaf);
5893                 }
5894                 if (found_extent) {
5895                         ret = remove_extent_backref(trans, extent_root, path,
5896                                                     iref, refs_to_drop,
5897                                                     is_data);
5898                         if (ret) {
5899                                 btrfs_abort_transaction(trans, extent_root, ret);
5900                                 goto out;
5901                         }
5902                 }
5903                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5904                                  root_objectid);
5905         } else {
5906                 if (found_extent) {
5907                         BUG_ON(is_data && refs_to_drop !=
5908                                extent_data_ref_count(root, path, iref));
5909                         if (iref) {
5910                                 BUG_ON(path->slots[0] != extent_slot);
5911                         } else {
5912                                 BUG_ON(path->slots[0] != extent_slot + 1);
5913                                 path->slots[0] = extent_slot;
5914                                 num_to_del = 2;
5915                         }
5916                 }
5917
5918                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5919                                       num_to_del);
5920                 if (ret) {
5921                         btrfs_abort_transaction(trans, extent_root, ret);
5922                         goto out;
5923                 }
5924                 btrfs_release_path(path);
5925
5926                 if (is_data) {
5927                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5928                         if (ret) {
5929                                 btrfs_abort_transaction(trans, extent_root, ret);
5930                                 goto out;
5931                         }
5932                 }
5933
5934                 ret = update_block_group(root, bytenr, num_bytes, 0);
5935                 if (ret) {
5936                         btrfs_abort_transaction(trans, extent_root, ret);
5937                         goto out;
5938                 }
5939         }
5940 out:
5941         btrfs_free_path(path);
5942         return ret;
5943 }
5944
5945 /*
5946  * when we free an block, it is possible (and likely) that we free the last
5947  * delayed ref for that extent as well.  This searches the delayed ref tree for
5948  * a given extent, and if there are no other delayed refs to be processed, it
5949  * removes it from the tree.
5950  */
5951 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5952                                       struct btrfs_root *root, u64 bytenr)
5953 {
5954         struct btrfs_delayed_ref_head *head;
5955         struct btrfs_delayed_ref_root *delayed_refs;
5956         struct btrfs_delayed_ref_node *ref;
5957         struct rb_node *node;
5958         int ret = 0;
5959
5960         delayed_refs = &trans->transaction->delayed_refs;
5961         spin_lock(&delayed_refs->lock);
5962         head = btrfs_find_delayed_ref_head(trans, bytenr);
5963         if (!head)
5964                 goto out;
5965
5966         node = rb_prev(&head->node.rb_node);
5967         if (!node)
5968                 goto out;
5969
5970         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5971
5972         /* there are still entries for this ref, we can't drop it */
5973         if (ref->bytenr == bytenr)
5974                 goto out;
5975
5976         if (head->extent_op) {
5977                 if (!head->must_insert_reserved)
5978                         goto out;
5979                 btrfs_free_delayed_extent_op(head->extent_op);
5980                 head->extent_op = NULL;
5981         }
5982
5983         /*
5984          * waiting for the lock here would deadlock.  If someone else has it
5985          * locked they are already in the process of dropping it anyway
5986          */
5987         if (!mutex_trylock(&head->mutex))
5988                 goto out;
5989
5990         /*
5991          * at this point we have a head with no other entries.  Go
5992          * ahead and process it.
5993          */
5994         head->node.in_tree = 0;
5995         rb_erase(&head->node.rb_node, &delayed_refs->root);
5996         rb_erase(&head->href_node, &delayed_refs->href_root);
5997
5998         delayed_refs->num_entries--;
5999
6000         /*
6001          * we don't take a ref on the node because we're removing it from the
6002          * tree, so we just steal the ref the tree was holding.
6003          */
6004         delayed_refs->num_heads--;
6005         if (list_empty(&head->cluster))
6006                 delayed_refs->num_heads_ready--;
6007
6008         list_del_init(&head->cluster);
6009         spin_unlock(&delayed_refs->lock);
6010
6011         BUG_ON(head->extent_op);
6012         if (head->must_insert_reserved)
6013                 ret = 1;
6014
6015         mutex_unlock(&head->mutex);
6016         btrfs_put_delayed_ref(&head->node);
6017         return ret;
6018 out:
6019         spin_unlock(&delayed_refs->lock);
6020         return 0;
6021 }
6022
6023 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6024                            struct btrfs_root *root,
6025                            struct extent_buffer *buf,
6026                            u64 parent, int last_ref)
6027 {
6028         struct btrfs_block_group_cache *cache = NULL;
6029         int pin = 1;
6030         int ret;
6031
6032         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6033                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6034                                         buf->start, buf->len,
6035                                         parent, root->root_key.objectid,
6036                                         btrfs_header_level(buf),
6037                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6038                 BUG_ON(ret); /* -ENOMEM */
6039         }
6040
6041         if (!last_ref)
6042                 return;
6043
6044         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6045
6046         if (btrfs_header_generation(buf) == trans->transid) {
6047                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6048                         ret = check_ref_cleanup(trans, root, buf->start);
6049                         if (!ret)
6050                                 goto out;
6051                 }
6052
6053                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6054                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6055                         goto out;
6056                 }
6057
6058                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6059
6060                 btrfs_add_free_space(cache, buf->start, buf->len);
6061                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
6062                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6063                 pin = 0;
6064         }
6065 out:
6066         if (pin)
6067                 add_pinned_bytes(root->fs_info, buf->len,
6068                                  btrfs_header_level(buf),
6069                                  root->root_key.objectid);
6070
6071         /*
6072          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6073          * anymore.
6074          */
6075         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6076         btrfs_put_block_group(cache);
6077 }
6078
6079 /* Can return -ENOMEM */
6080 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6081                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6082                       u64 owner, u64 offset, int for_cow)
6083 {
6084         int ret;
6085         struct btrfs_fs_info *fs_info = root->fs_info;
6086
6087         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6088
6089         /*
6090          * tree log blocks never actually go into the extent allocation
6091          * tree, just update pinning info and exit early.
6092          */
6093         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6094                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6095                 /* unlocks the pinned mutex */
6096                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6097                 ret = 0;
6098         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6099                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6100                                         num_bytes,
6101                                         parent, root_objectid, (int)owner,
6102                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
6103         } else {
6104                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6105                                                 num_bytes,
6106                                                 parent, root_objectid, owner,
6107                                                 offset, BTRFS_DROP_DELAYED_REF,
6108                                                 NULL, for_cow);
6109         }
6110         return ret;
6111 }
6112
6113 static u64 stripe_align(struct btrfs_root *root,
6114                         struct btrfs_block_group_cache *cache,
6115                         u64 val, u64 num_bytes)
6116 {
6117         u64 ret = ALIGN(val, root->stripesize);
6118         return ret;
6119 }
6120
6121 /*
6122  * when we wait for progress in the block group caching, its because
6123  * our allocation attempt failed at least once.  So, we must sleep
6124  * and let some progress happen before we try again.
6125  *
6126  * This function will sleep at least once waiting for new free space to
6127  * show up, and then it will check the block group free space numbers
6128  * for our min num_bytes.  Another option is to have it go ahead
6129  * and look in the rbtree for a free extent of a given size, but this
6130  * is a good start.
6131  *
6132  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6133  * any of the information in this block group.
6134  */
6135 static noinline void
6136 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6137                                 u64 num_bytes)
6138 {
6139         struct btrfs_caching_control *caching_ctl;
6140
6141         caching_ctl = get_caching_control(cache);
6142         if (!caching_ctl)
6143                 return;
6144
6145         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6146                    (cache->free_space_ctl->free_space >= num_bytes));
6147
6148         put_caching_control(caching_ctl);
6149 }
6150
6151 static noinline int
6152 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6153 {
6154         struct btrfs_caching_control *caching_ctl;
6155         int ret = 0;
6156
6157         caching_ctl = get_caching_control(cache);
6158         if (!caching_ctl)
6159                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6160
6161         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6162         if (cache->cached == BTRFS_CACHE_ERROR)
6163                 ret = -EIO;
6164         put_caching_control(caching_ctl);
6165         return ret;
6166 }
6167
6168 int __get_raid_index(u64 flags)
6169 {
6170         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6171                 return BTRFS_RAID_RAID10;
6172         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6173                 return BTRFS_RAID_RAID1;
6174         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6175                 return BTRFS_RAID_DUP;
6176         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6177                 return BTRFS_RAID_RAID0;
6178         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6179                 return BTRFS_RAID_RAID5;
6180         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6181                 return BTRFS_RAID_RAID6;
6182
6183         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6184 }
6185
6186 int get_block_group_index(struct btrfs_block_group_cache *cache)
6187 {
6188         return __get_raid_index(cache->flags);
6189 }
6190
6191 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6192         [BTRFS_RAID_RAID10]     = "raid10",
6193         [BTRFS_RAID_RAID1]      = "raid1",
6194         [BTRFS_RAID_DUP]        = "dup",
6195         [BTRFS_RAID_RAID0]      = "raid0",
6196         [BTRFS_RAID_SINGLE]     = "single",
6197         [BTRFS_RAID_RAID5]      = "raid5",
6198         [BTRFS_RAID_RAID6]      = "raid6",
6199 };
6200
6201 static const char *get_raid_name(enum btrfs_raid_types type)
6202 {
6203         if (type >= BTRFS_NR_RAID_TYPES)
6204                 return NULL;
6205
6206         return btrfs_raid_type_names[type];
6207 }
6208
6209 enum btrfs_loop_type {
6210         LOOP_CACHING_NOWAIT = 0,
6211         LOOP_CACHING_WAIT = 1,
6212         LOOP_ALLOC_CHUNK = 2,
6213         LOOP_NO_EMPTY_SIZE = 3,
6214 };
6215
6216 /*
6217  * walks the btree of allocated extents and find a hole of a given size.
6218  * The key ins is changed to record the hole:
6219  * ins->objectid == start position
6220  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6221  * ins->offset == the size of the hole.
6222  * Any available blocks before search_start are skipped.
6223  *
6224  * If there is no suitable free space, we will record the max size of
6225  * the free space extent currently.
6226  */
6227 static noinline int find_free_extent(struct btrfs_root *orig_root,
6228                                      u64 num_bytes, u64 empty_size,
6229                                      u64 hint_byte, struct btrfs_key *ins,
6230                                      u64 flags)
6231 {
6232         int ret = 0;
6233         struct btrfs_root *root = orig_root->fs_info->extent_root;
6234         struct btrfs_free_cluster *last_ptr = NULL;
6235         struct btrfs_block_group_cache *block_group = NULL;
6236         struct btrfs_block_group_cache *used_block_group;
6237         u64 search_start = 0;
6238         u64 max_extent_size = 0;
6239         int empty_cluster = 2 * 1024 * 1024;
6240         struct btrfs_space_info *space_info;
6241         int loop = 0;
6242         int index = __get_raid_index(flags);
6243         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6244                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6245         bool failed_cluster_refill = false;
6246         bool failed_alloc = false;
6247         bool use_cluster = true;
6248         bool have_caching_bg = false;
6249
6250         WARN_ON(num_bytes < root->sectorsize);
6251         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6252         ins->objectid = 0;
6253         ins->offset = 0;
6254
6255         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6256
6257         space_info = __find_space_info(root->fs_info, flags);
6258         if (!space_info) {
6259                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6260                 return -ENOSPC;
6261         }
6262
6263         /*
6264          * If the space info is for both data and metadata it means we have a
6265          * small filesystem and we can't use the clustering stuff.
6266          */
6267         if (btrfs_mixed_space_info(space_info))
6268                 use_cluster = false;
6269
6270         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6271                 last_ptr = &root->fs_info->meta_alloc_cluster;
6272                 if (!btrfs_test_opt(root, SSD))
6273                         empty_cluster = 64 * 1024;
6274         }
6275
6276         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6277             btrfs_test_opt(root, SSD)) {
6278                 last_ptr = &root->fs_info->data_alloc_cluster;
6279         }
6280
6281         if (last_ptr) {
6282                 spin_lock(&last_ptr->lock);
6283                 if (last_ptr->block_group)
6284                         hint_byte = last_ptr->window_start;
6285                 spin_unlock(&last_ptr->lock);
6286         }
6287
6288         search_start = max(search_start, first_logical_byte(root, 0));
6289         search_start = max(search_start, hint_byte);
6290
6291         if (!last_ptr)
6292                 empty_cluster = 0;
6293
6294         if (search_start == hint_byte) {
6295                 block_group = btrfs_lookup_block_group(root->fs_info,
6296                                                        search_start);
6297                 used_block_group = block_group;
6298                 /*
6299                  * we don't want to use the block group if it doesn't match our
6300                  * allocation bits, or if its not cached.
6301                  *
6302                  * However if we are re-searching with an ideal block group
6303                  * picked out then we don't care that the block group is cached.
6304                  */
6305                 if (block_group && block_group_bits(block_group, flags) &&
6306                     block_group->cached != BTRFS_CACHE_NO) {
6307                         down_read(&space_info->groups_sem);
6308                         if (list_empty(&block_group->list) ||
6309                             block_group->ro) {
6310                                 /*
6311                                  * someone is removing this block group,
6312                                  * we can't jump into the have_block_group
6313                                  * target because our list pointers are not
6314                                  * valid
6315                                  */
6316                                 btrfs_put_block_group(block_group);
6317                                 up_read(&space_info->groups_sem);
6318                         } else {
6319                                 index = get_block_group_index(block_group);
6320                                 goto have_block_group;
6321                         }
6322                 } else if (block_group) {
6323                         btrfs_put_block_group(block_group);
6324                 }
6325         }
6326 search:
6327         have_caching_bg = false;
6328         down_read(&space_info->groups_sem);
6329         list_for_each_entry(block_group, &space_info->block_groups[index],
6330                             list) {
6331                 u64 offset;
6332                 int cached;
6333
6334                 used_block_group = block_group;
6335                 btrfs_get_block_group(block_group);
6336                 search_start = block_group->key.objectid;
6337
6338                 /*
6339                  * this can happen if we end up cycling through all the
6340                  * raid types, but we want to make sure we only allocate
6341                  * for the proper type.
6342                  */
6343                 if (!block_group_bits(block_group, flags)) {
6344                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6345                                 BTRFS_BLOCK_GROUP_RAID1 |
6346                                 BTRFS_BLOCK_GROUP_RAID5 |
6347                                 BTRFS_BLOCK_GROUP_RAID6 |
6348                                 BTRFS_BLOCK_GROUP_RAID10;
6349
6350                         /*
6351                          * if they asked for extra copies and this block group
6352                          * doesn't provide them, bail.  This does allow us to
6353                          * fill raid0 from raid1.
6354                          */
6355                         if ((flags & extra) && !(block_group->flags & extra))
6356                                 goto loop;
6357                 }
6358
6359 have_block_group:
6360                 cached = block_group_cache_done(block_group);
6361                 if (unlikely(!cached)) {
6362                         ret = cache_block_group(block_group, 0);
6363                         BUG_ON(ret < 0);
6364                         ret = 0;
6365                 }
6366
6367                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6368                         goto loop;
6369                 if (unlikely(block_group->ro))
6370                         goto loop;
6371
6372                 /*
6373                  * Ok we want to try and use the cluster allocator, so
6374                  * lets look there
6375                  */
6376                 if (last_ptr) {
6377                         unsigned long aligned_cluster;
6378                         /*
6379                          * the refill lock keeps out other
6380                          * people trying to start a new cluster
6381                          */
6382                         spin_lock(&last_ptr->refill_lock);
6383                         used_block_group = last_ptr->block_group;
6384                         if (used_block_group != block_group &&
6385                             (!used_block_group ||
6386                              used_block_group->ro ||
6387                              !block_group_bits(used_block_group, flags))) {
6388                                 used_block_group = block_group;
6389                                 goto refill_cluster;
6390                         }
6391
6392                         if (used_block_group != block_group)
6393                                 btrfs_get_block_group(used_block_group);
6394
6395                         offset = btrfs_alloc_from_cluster(used_block_group,
6396                                                 last_ptr,
6397                                                 num_bytes,
6398                                                 used_block_group->key.objectid,
6399                                                 &max_extent_size);
6400                         if (offset) {
6401                                 /* we have a block, we're done */
6402                                 spin_unlock(&last_ptr->refill_lock);
6403                                 trace_btrfs_reserve_extent_cluster(root,
6404                                         block_group, search_start, num_bytes);
6405                                 goto checks;
6406                         }
6407
6408                         WARN_ON(last_ptr->block_group != used_block_group);
6409                         if (used_block_group != block_group) {
6410                                 btrfs_put_block_group(used_block_group);
6411                                 used_block_group = block_group;
6412                         }
6413 refill_cluster:
6414                         BUG_ON(used_block_group != block_group);
6415                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6416                          * set up a new clusters, so lets just skip it
6417                          * and let the allocator find whatever block
6418                          * it can find.  If we reach this point, we
6419                          * will have tried the cluster allocator
6420                          * plenty of times and not have found
6421                          * anything, so we are likely way too
6422                          * fragmented for the clustering stuff to find
6423                          * anything.
6424                          *
6425                          * However, if the cluster is taken from the
6426                          * current block group, release the cluster
6427                          * first, so that we stand a better chance of
6428                          * succeeding in the unclustered
6429                          * allocation.  */
6430                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6431                             last_ptr->block_group != block_group) {
6432                                 spin_unlock(&last_ptr->refill_lock);
6433                                 goto unclustered_alloc;
6434                         }
6435
6436                         /*
6437                          * this cluster didn't work out, free it and
6438                          * start over
6439                          */
6440                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6441
6442                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6443                                 spin_unlock(&last_ptr->refill_lock);
6444                                 goto unclustered_alloc;
6445                         }
6446
6447                         aligned_cluster = max_t(unsigned long,
6448                                                 empty_cluster + empty_size,
6449                                               block_group->full_stripe_len);
6450
6451                         /* allocate a cluster in this block group */
6452                         ret = btrfs_find_space_cluster(root, block_group,
6453                                                        last_ptr, search_start,
6454                                                        num_bytes,
6455                                                        aligned_cluster);
6456                         if (ret == 0) {
6457                                 /*
6458                                  * now pull our allocation out of this
6459                                  * cluster
6460                                  */
6461                                 offset = btrfs_alloc_from_cluster(block_group,
6462                                                         last_ptr,
6463                                                         num_bytes,
6464                                                         search_start,
6465                                                         &max_extent_size);
6466                                 if (offset) {
6467                                         /* we found one, proceed */
6468                                         spin_unlock(&last_ptr->refill_lock);
6469                                         trace_btrfs_reserve_extent_cluster(root,
6470                                                 block_group, search_start,
6471                                                 num_bytes);
6472                                         goto checks;
6473                                 }
6474                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6475                                    && !failed_cluster_refill) {
6476                                 spin_unlock(&last_ptr->refill_lock);
6477
6478                                 failed_cluster_refill = true;
6479                                 wait_block_group_cache_progress(block_group,
6480                                        num_bytes + empty_cluster + empty_size);
6481                                 goto have_block_group;
6482                         }
6483
6484                         /*
6485                          * at this point we either didn't find a cluster
6486                          * or we weren't able to allocate a block from our
6487                          * cluster.  Free the cluster we've been trying
6488                          * to use, and go to the next block group
6489                          */
6490                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6491                         spin_unlock(&last_ptr->refill_lock);
6492                         goto loop;
6493                 }
6494
6495 unclustered_alloc:
6496                 spin_lock(&block_group->free_space_ctl->tree_lock);
6497                 if (cached &&
6498                     block_group->free_space_ctl->free_space <
6499                     num_bytes + empty_cluster + empty_size) {
6500                         if (block_group->free_space_ctl->free_space >
6501                             max_extent_size)
6502                                 max_extent_size =
6503                                         block_group->free_space_ctl->free_space;
6504                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6505                         goto loop;
6506                 }
6507                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6508
6509                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6510                                                     num_bytes, empty_size,
6511                                                     &max_extent_size);
6512                 /*
6513                  * If we didn't find a chunk, and we haven't failed on this
6514                  * block group before, and this block group is in the middle of
6515                  * caching and we are ok with waiting, then go ahead and wait
6516                  * for progress to be made, and set failed_alloc to true.
6517                  *
6518                  * If failed_alloc is true then we've already waited on this
6519                  * block group once and should move on to the next block group.
6520                  */
6521                 if (!offset && !failed_alloc && !cached &&
6522                     loop > LOOP_CACHING_NOWAIT) {
6523                         wait_block_group_cache_progress(block_group,
6524                                                 num_bytes + empty_size);
6525                         failed_alloc = true;
6526                         goto have_block_group;
6527                 } else if (!offset) {
6528                         if (!cached)
6529                                 have_caching_bg = true;
6530                         goto loop;
6531                 }
6532 checks:
6533                 search_start = stripe_align(root, used_block_group,
6534                                             offset, num_bytes);
6535
6536                 /* move on to the next group */
6537                 if (search_start + num_bytes >
6538                     used_block_group->key.objectid + used_block_group->key.offset) {
6539                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6540                         goto loop;
6541                 }
6542
6543                 if (offset < search_start)
6544                         btrfs_add_free_space(used_block_group, offset,
6545                                              search_start - offset);
6546                 BUG_ON(offset > search_start);
6547
6548                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6549                                                   alloc_type);
6550                 if (ret == -EAGAIN) {
6551                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6552                         goto loop;
6553                 }
6554
6555                 /* we are all good, lets return */
6556                 ins->objectid = search_start;
6557                 ins->offset = num_bytes;
6558
6559                 trace_btrfs_reserve_extent(orig_root, block_group,
6560                                            search_start, num_bytes);
6561                 if (used_block_group != block_group)
6562                         btrfs_put_block_group(used_block_group);
6563                 btrfs_put_block_group(block_group);
6564                 break;
6565 loop:
6566                 failed_cluster_refill = false;
6567                 failed_alloc = false;
6568                 BUG_ON(index != get_block_group_index(block_group));
6569                 if (used_block_group != block_group)
6570                         btrfs_put_block_group(used_block_group);
6571                 btrfs_put_block_group(block_group);
6572         }
6573         up_read(&space_info->groups_sem);
6574
6575         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6576                 goto search;
6577
6578         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6579                 goto search;
6580
6581         /*
6582          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6583          *                      caching kthreads as we move along
6584          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6585          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6586          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6587          *                      again
6588          */
6589         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6590                 index = 0;
6591                 loop++;
6592                 if (loop == LOOP_ALLOC_CHUNK) {
6593                         struct btrfs_trans_handle *trans;
6594
6595                         trans = btrfs_join_transaction(root);
6596                         if (IS_ERR(trans)) {
6597                                 ret = PTR_ERR(trans);
6598                                 goto out;
6599                         }
6600
6601                         ret = do_chunk_alloc(trans, root, flags,
6602                                              CHUNK_ALLOC_FORCE);
6603                         /*
6604                          * Do not bail out on ENOSPC since we
6605                          * can do more things.
6606                          */
6607                         if (ret < 0 && ret != -ENOSPC)
6608                                 btrfs_abort_transaction(trans,
6609                                                         root, ret);
6610                         else
6611                                 ret = 0;
6612                         btrfs_end_transaction(trans, root);
6613                         if (ret)
6614                                 goto out;
6615                 }
6616
6617                 if (loop == LOOP_NO_EMPTY_SIZE) {
6618                         empty_size = 0;
6619                         empty_cluster = 0;
6620                 }
6621
6622                 goto search;
6623         } else if (!ins->objectid) {
6624                 ret = -ENOSPC;
6625         } else if (ins->objectid) {
6626                 ret = 0;
6627         }
6628 out:
6629         if (ret == -ENOSPC)
6630                 ins->offset = max_extent_size;
6631         return ret;
6632 }
6633
6634 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6635                             int dump_block_groups)
6636 {
6637         struct btrfs_block_group_cache *cache;
6638         int index = 0;
6639
6640         spin_lock(&info->lock);
6641         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
6642                info->flags,
6643                info->total_bytes - info->bytes_used - info->bytes_pinned -
6644                info->bytes_reserved - info->bytes_readonly,
6645                (info->full) ? "" : "not ");
6646         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
6647                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6648                info->total_bytes, info->bytes_used, info->bytes_pinned,
6649                info->bytes_reserved, info->bytes_may_use,
6650                info->bytes_readonly);
6651         spin_unlock(&info->lock);
6652
6653         if (!dump_block_groups)
6654                 return;
6655
6656         down_read(&info->groups_sem);
6657 again:
6658         list_for_each_entry(cache, &info->block_groups[index], list) {
6659                 spin_lock(&cache->lock);
6660                 printk(KERN_INFO "BTRFS: "
6661                            "block group %llu has %llu bytes, "
6662                            "%llu used %llu pinned %llu reserved %s\n",
6663                        cache->key.objectid, cache->key.offset,
6664                        btrfs_block_group_used(&cache->item), cache->pinned,
6665                        cache->reserved, cache->ro ? "[readonly]" : "");
6666                 btrfs_dump_free_space(cache, bytes);
6667                 spin_unlock(&cache->lock);
6668         }
6669         if (++index < BTRFS_NR_RAID_TYPES)
6670                 goto again;
6671         up_read(&info->groups_sem);
6672 }
6673
6674 int btrfs_reserve_extent(struct btrfs_root *root,
6675                          u64 num_bytes, u64 min_alloc_size,
6676                          u64 empty_size, u64 hint_byte,
6677                          struct btrfs_key *ins, int is_data)
6678 {
6679         bool final_tried = false;
6680         u64 flags;
6681         int ret;
6682
6683         flags = btrfs_get_alloc_profile(root, is_data);
6684 again:
6685         WARN_ON(num_bytes < root->sectorsize);
6686         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6687                                flags);
6688
6689         if (ret == -ENOSPC) {
6690                 if (!final_tried && ins->offset) {
6691                         num_bytes = min(num_bytes >> 1, ins->offset);
6692                         num_bytes = round_down(num_bytes, root->sectorsize);
6693                         num_bytes = max(num_bytes, min_alloc_size);
6694                         if (num_bytes == min_alloc_size)
6695                                 final_tried = true;
6696                         goto again;
6697                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6698                         struct btrfs_space_info *sinfo;
6699
6700                         sinfo = __find_space_info(root->fs_info, flags);
6701                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6702                                 flags, num_bytes);
6703                         if (sinfo)
6704                                 dump_space_info(sinfo, num_bytes, 1);
6705                 }
6706         }
6707
6708         return ret;
6709 }
6710
6711 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6712                                         u64 start, u64 len, int pin)
6713 {
6714         struct btrfs_block_group_cache *cache;
6715         int ret = 0;
6716
6717         cache = btrfs_lookup_block_group(root->fs_info, start);
6718         if (!cache) {
6719                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6720                         start);
6721                 return -ENOSPC;
6722         }
6723
6724         if (btrfs_test_opt(root, DISCARD))
6725                 ret = btrfs_discard_extent(root, start, len, NULL);
6726
6727         if (pin)
6728                 pin_down_extent(root, cache, start, len, 1);
6729         else {
6730                 btrfs_add_free_space(cache, start, len);
6731                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6732         }
6733         btrfs_put_block_group(cache);
6734
6735         trace_btrfs_reserved_extent_free(root, start, len);
6736
6737         return ret;
6738 }
6739
6740 int btrfs_free_reserved_extent(struct btrfs_root *root,
6741                                         u64 start, u64 len)
6742 {
6743         return __btrfs_free_reserved_extent(root, start, len, 0);
6744 }
6745
6746 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6747                                        u64 start, u64 len)
6748 {
6749         return __btrfs_free_reserved_extent(root, start, len, 1);
6750 }
6751
6752 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6753                                       struct btrfs_root *root,
6754                                       u64 parent, u64 root_objectid,
6755                                       u64 flags, u64 owner, u64 offset,
6756                                       struct btrfs_key *ins, int ref_mod)
6757 {
6758         int ret;
6759         struct btrfs_fs_info *fs_info = root->fs_info;
6760         struct btrfs_extent_item *extent_item;
6761         struct btrfs_extent_inline_ref *iref;
6762         struct btrfs_path *path;
6763         struct extent_buffer *leaf;
6764         int type;
6765         u32 size;
6766
6767         if (parent > 0)
6768                 type = BTRFS_SHARED_DATA_REF_KEY;
6769         else
6770                 type = BTRFS_EXTENT_DATA_REF_KEY;
6771
6772         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6773
6774         path = btrfs_alloc_path();
6775         if (!path)
6776                 return -ENOMEM;
6777
6778         path->leave_spinning = 1;
6779         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6780                                       ins, size);
6781         if (ret) {
6782                 btrfs_free_path(path);
6783                 return ret;
6784         }
6785
6786         leaf = path->nodes[0];
6787         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6788                                      struct btrfs_extent_item);
6789         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6790         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6791         btrfs_set_extent_flags(leaf, extent_item,
6792                                flags | BTRFS_EXTENT_FLAG_DATA);
6793
6794         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6795         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6796         if (parent > 0) {
6797                 struct btrfs_shared_data_ref *ref;
6798                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6799                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6800                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6801         } else {
6802                 struct btrfs_extent_data_ref *ref;
6803                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6804                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6805                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6806                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6807                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6808         }
6809
6810         btrfs_mark_buffer_dirty(path->nodes[0]);
6811         btrfs_free_path(path);
6812
6813         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6814         if (ret) { /* -ENOENT, logic error */
6815                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6816                         ins->objectid, ins->offset);
6817                 BUG();
6818         }
6819         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6820         return ret;
6821 }
6822
6823 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6824                                      struct btrfs_root *root,
6825                                      u64 parent, u64 root_objectid,
6826                                      u64 flags, struct btrfs_disk_key *key,
6827                                      int level, struct btrfs_key *ins)
6828 {
6829         int ret;
6830         struct btrfs_fs_info *fs_info = root->fs_info;
6831         struct btrfs_extent_item *extent_item;
6832         struct btrfs_tree_block_info *block_info;
6833         struct btrfs_extent_inline_ref *iref;
6834         struct btrfs_path *path;
6835         struct extent_buffer *leaf;
6836         u32 size = sizeof(*extent_item) + sizeof(*iref);
6837         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6838                                                  SKINNY_METADATA);
6839
6840         if (!skinny_metadata)
6841                 size += sizeof(*block_info);
6842
6843         path = btrfs_alloc_path();
6844         if (!path) {
6845                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6846                                                    root->leafsize);
6847                 return -ENOMEM;
6848         }
6849
6850         path->leave_spinning = 1;
6851         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6852                                       ins, size);
6853         if (ret) {
6854                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6855                                                    root->leafsize);
6856                 btrfs_free_path(path);
6857                 return ret;
6858         }
6859
6860         leaf = path->nodes[0];
6861         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6862                                      struct btrfs_extent_item);
6863         btrfs_set_extent_refs(leaf, extent_item, 1);
6864         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6865         btrfs_set_extent_flags(leaf, extent_item,
6866                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6867
6868         if (skinny_metadata) {
6869                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6870         } else {
6871                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6872                 btrfs_set_tree_block_key(leaf, block_info, key);
6873                 btrfs_set_tree_block_level(leaf, block_info, level);
6874                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6875         }
6876
6877         if (parent > 0) {
6878                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6879                 btrfs_set_extent_inline_ref_type(leaf, iref,
6880                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6881                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6882         } else {
6883                 btrfs_set_extent_inline_ref_type(leaf, iref,
6884                                                  BTRFS_TREE_BLOCK_REF_KEY);
6885                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6886         }
6887
6888         btrfs_mark_buffer_dirty(leaf);
6889         btrfs_free_path(path);
6890
6891         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6892         if (ret) { /* -ENOENT, logic error */
6893                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6894                         ins->objectid, ins->offset);
6895                 BUG();
6896         }
6897
6898         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->leafsize);
6899         return ret;
6900 }
6901
6902 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6903                                      struct btrfs_root *root,
6904                                      u64 root_objectid, u64 owner,
6905                                      u64 offset, struct btrfs_key *ins)
6906 {
6907         int ret;
6908
6909         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6910
6911         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6912                                          ins->offset, 0,
6913                                          root_objectid, owner, offset,
6914                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6915         return ret;
6916 }
6917
6918 /*
6919  * this is used by the tree logging recovery code.  It records that
6920  * an extent has been allocated and makes sure to clear the free
6921  * space cache bits as well
6922  */
6923 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6924                                    struct btrfs_root *root,
6925                                    u64 root_objectid, u64 owner, u64 offset,
6926                                    struct btrfs_key *ins)
6927 {
6928         int ret;
6929         struct btrfs_block_group_cache *block_group;
6930
6931         /*
6932          * Mixed block groups will exclude before processing the log so we only
6933          * need to do the exlude dance if this fs isn't mixed.
6934          */
6935         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6936                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6937                 if (ret)
6938                         return ret;
6939         }
6940
6941         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6942         if (!block_group)
6943                 return -EINVAL;
6944
6945         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6946                                           RESERVE_ALLOC_NO_ACCOUNT);
6947         BUG_ON(ret); /* logic error */
6948         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6949                                          0, owner, offset, ins, 1);
6950         btrfs_put_block_group(block_group);
6951         return ret;
6952 }
6953
6954 static struct extent_buffer *
6955 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6956                       u64 bytenr, u32 blocksize, int level)
6957 {
6958         struct extent_buffer *buf;
6959
6960         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6961         if (!buf)
6962                 return ERR_PTR(-ENOMEM);
6963         btrfs_set_header_generation(buf, trans->transid);
6964         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6965         btrfs_tree_lock(buf);
6966         clean_tree_block(trans, root, buf);
6967         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6968
6969         btrfs_set_lock_blocking(buf);
6970         btrfs_set_buffer_uptodate(buf);
6971
6972         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6973                 /*
6974                  * we allow two log transactions at a time, use different
6975                  * EXENT bit to differentiate dirty pages.
6976                  */
6977                 if (root->log_transid % 2 == 0)
6978                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6979                                         buf->start + buf->len - 1, GFP_NOFS);
6980                 else
6981                         set_extent_new(&root->dirty_log_pages, buf->start,
6982                                         buf->start + buf->len - 1, GFP_NOFS);
6983         } else {
6984                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6985                          buf->start + buf->len - 1, GFP_NOFS);
6986         }
6987         trans->blocks_used++;
6988         /* this returns a buffer locked for blocking */
6989         return buf;
6990 }
6991
6992 static struct btrfs_block_rsv *
6993 use_block_rsv(struct btrfs_trans_handle *trans,
6994               struct btrfs_root *root, u32 blocksize)
6995 {
6996         struct btrfs_block_rsv *block_rsv;
6997         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6998         int ret;
6999         bool global_updated = false;
7000
7001         block_rsv = get_block_rsv(trans, root);
7002
7003         if (unlikely(block_rsv->size == 0))
7004                 goto try_reserve;
7005 again:
7006         ret = block_rsv_use_bytes(block_rsv, blocksize);
7007         if (!ret)
7008                 return block_rsv;
7009
7010         if (block_rsv->failfast)
7011                 return ERR_PTR(ret);
7012
7013         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7014                 global_updated = true;
7015                 update_global_block_rsv(root->fs_info);
7016                 goto again;
7017         }
7018
7019         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7020                 static DEFINE_RATELIMIT_STATE(_rs,
7021                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7022                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7023                 if (__ratelimit(&_rs))
7024                         WARN(1, KERN_DEBUG
7025                                 "BTRFS: block rsv returned %d\n", ret);
7026         }
7027 try_reserve:
7028         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7029                                      BTRFS_RESERVE_NO_FLUSH);
7030         if (!ret)
7031                 return block_rsv;
7032         /*
7033          * If we couldn't reserve metadata bytes try and use some from
7034          * the global reserve if its space type is the same as the global
7035          * reservation.
7036          */
7037         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7038             block_rsv->space_info == global_rsv->space_info) {
7039                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7040                 if (!ret)
7041                         return global_rsv;
7042         }
7043         return ERR_PTR(ret);
7044 }
7045
7046 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7047                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7048 {
7049         block_rsv_add_bytes(block_rsv, blocksize, 0);
7050         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7051 }
7052
7053 /*
7054  * finds a free extent and does all the dirty work required for allocation
7055  * returns the key for the extent through ins, and a tree buffer for
7056  * the first block of the extent through buf.
7057  *
7058  * returns the tree buffer or NULL.
7059  */
7060 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
7061                                         struct btrfs_root *root, u32 blocksize,
7062                                         u64 parent, u64 root_objectid,
7063                                         struct btrfs_disk_key *key, int level,
7064                                         u64 hint, u64 empty_size)
7065 {
7066         struct btrfs_key ins;
7067         struct btrfs_block_rsv *block_rsv;
7068         struct extent_buffer *buf;
7069         u64 flags = 0;
7070         int ret;
7071         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7072                                                  SKINNY_METADATA);
7073
7074         block_rsv = use_block_rsv(trans, root, blocksize);
7075         if (IS_ERR(block_rsv))
7076                 return ERR_CAST(block_rsv);
7077
7078         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7079                                    empty_size, hint, &ins, 0);
7080         if (ret) {
7081                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7082                 return ERR_PTR(ret);
7083         }
7084
7085         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
7086                                     blocksize, level);
7087         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
7088
7089         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7090                 if (parent == 0)
7091                         parent = ins.objectid;
7092                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7093         } else
7094                 BUG_ON(parent > 0);
7095
7096         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7097                 struct btrfs_delayed_extent_op *extent_op;
7098                 extent_op = btrfs_alloc_delayed_extent_op();
7099                 BUG_ON(!extent_op); /* -ENOMEM */
7100                 if (key)
7101                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7102                 else
7103                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7104                 extent_op->flags_to_set = flags;
7105                 if (skinny_metadata)
7106                         extent_op->update_key = 0;
7107                 else
7108                         extent_op->update_key = 1;
7109                 extent_op->update_flags = 1;
7110                 extent_op->is_data = 0;
7111                 extent_op->level = level;
7112
7113                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7114                                         ins.objectid,
7115                                         ins.offset, parent, root_objectid,
7116                                         level, BTRFS_ADD_DELAYED_EXTENT,
7117                                         extent_op, 0);
7118                 BUG_ON(ret); /* -ENOMEM */
7119         }
7120         return buf;
7121 }
7122
7123 struct walk_control {
7124         u64 refs[BTRFS_MAX_LEVEL];
7125         u64 flags[BTRFS_MAX_LEVEL];
7126         struct btrfs_key update_progress;
7127         int stage;
7128         int level;
7129         int shared_level;
7130         int update_ref;
7131         int keep_locks;
7132         int reada_slot;
7133         int reada_count;
7134         int for_reloc;
7135 };
7136
7137 #define DROP_REFERENCE  1
7138 #define UPDATE_BACKREF  2
7139
7140 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7141                                      struct btrfs_root *root,
7142                                      struct walk_control *wc,
7143                                      struct btrfs_path *path)
7144 {
7145         u64 bytenr;
7146         u64 generation;
7147         u64 refs;
7148         u64 flags;
7149         u32 nritems;
7150         u32 blocksize;
7151         struct btrfs_key key;
7152         struct extent_buffer *eb;
7153         int ret;
7154         int slot;
7155         int nread = 0;
7156
7157         if (path->slots[wc->level] < wc->reada_slot) {
7158                 wc->reada_count = wc->reada_count * 2 / 3;
7159                 wc->reada_count = max(wc->reada_count, 2);
7160         } else {
7161                 wc->reada_count = wc->reada_count * 3 / 2;
7162                 wc->reada_count = min_t(int, wc->reada_count,
7163                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7164         }
7165
7166         eb = path->nodes[wc->level];
7167         nritems = btrfs_header_nritems(eb);
7168         blocksize = btrfs_level_size(root, wc->level - 1);
7169
7170         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7171                 if (nread >= wc->reada_count)
7172                         break;
7173
7174                 cond_resched();
7175                 bytenr = btrfs_node_blockptr(eb, slot);
7176                 generation = btrfs_node_ptr_generation(eb, slot);
7177
7178                 if (slot == path->slots[wc->level])
7179                         goto reada;
7180
7181                 if (wc->stage == UPDATE_BACKREF &&
7182                     generation <= root->root_key.offset)
7183                         continue;
7184
7185                 /* We don't lock the tree block, it's OK to be racy here */
7186                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7187                                                wc->level - 1, 1, &refs,
7188                                                &flags);
7189                 /* We don't care about errors in readahead. */
7190                 if (ret < 0)
7191                         continue;
7192                 BUG_ON(refs == 0);
7193
7194                 if (wc->stage == DROP_REFERENCE) {
7195                         if (refs == 1)
7196                                 goto reada;
7197
7198                         if (wc->level == 1 &&
7199                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7200                                 continue;
7201                         if (!wc->update_ref ||
7202                             generation <= root->root_key.offset)
7203                                 continue;
7204                         btrfs_node_key_to_cpu(eb, &key, slot);
7205                         ret = btrfs_comp_cpu_keys(&key,
7206                                                   &wc->update_progress);
7207                         if (ret < 0)
7208                                 continue;
7209                 } else {
7210                         if (wc->level == 1 &&
7211                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7212                                 continue;
7213                 }
7214 reada:
7215                 ret = readahead_tree_block(root, bytenr, blocksize,
7216                                            generation);
7217                 if (ret)
7218                         break;
7219                 nread++;
7220         }
7221         wc->reada_slot = slot;
7222 }
7223
7224 /*
7225  * helper to process tree block while walking down the tree.
7226  *
7227  * when wc->stage == UPDATE_BACKREF, this function updates
7228  * back refs for pointers in the block.
7229  *
7230  * NOTE: return value 1 means we should stop walking down.
7231  */
7232 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7233                                    struct btrfs_root *root,
7234                                    struct btrfs_path *path,
7235                                    struct walk_control *wc, int lookup_info)
7236 {
7237         int level = wc->level;
7238         struct extent_buffer *eb = path->nodes[level];
7239         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7240         int ret;
7241
7242         if (wc->stage == UPDATE_BACKREF &&
7243             btrfs_header_owner(eb) != root->root_key.objectid)
7244                 return 1;
7245
7246         /*
7247          * when reference count of tree block is 1, it won't increase
7248          * again. once full backref flag is set, we never clear it.
7249          */
7250         if (lookup_info &&
7251             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7252              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7253                 BUG_ON(!path->locks[level]);
7254                 ret = btrfs_lookup_extent_info(trans, root,
7255                                                eb->start, level, 1,
7256                                                &wc->refs[level],
7257                                                &wc->flags[level]);
7258                 BUG_ON(ret == -ENOMEM);
7259                 if (ret)
7260                         return ret;
7261                 BUG_ON(wc->refs[level] == 0);
7262         }
7263
7264         if (wc->stage == DROP_REFERENCE) {
7265                 if (wc->refs[level] > 1)
7266                         return 1;
7267
7268                 if (path->locks[level] && !wc->keep_locks) {
7269                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7270                         path->locks[level] = 0;
7271                 }
7272                 return 0;
7273         }
7274
7275         /* wc->stage == UPDATE_BACKREF */
7276         if (!(wc->flags[level] & flag)) {
7277                 BUG_ON(!path->locks[level]);
7278                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7279                 BUG_ON(ret); /* -ENOMEM */
7280                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7281                 BUG_ON(ret); /* -ENOMEM */
7282                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7283                                                   eb->len, flag,
7284                                                   btrfs_header_level(eb), 0);
7285                 BUG_ON(ret); /* -ENOMEM */
7286                 wc->flags[level] |= flag;
7287         }
7288
7289         /*
7290          * the block is shared by multiple trees, so it's not good to
7291          * keep the tree lock
7292          */
7293         if (path->locks[level] && level > 0) {
7294                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7295                 path->locks[level] = 0;
7296         }
7297         return 0;
7298 }
7299
7300 /*
7301  * helper to process tree block pointer.
7302  *
7303  * when wc->stage == DROP_REFERENCE, this function checks
7304  * reference count of the block pointed to. if the block
7305  * is shared and we need update back refs for the subtree
7306  * rooted at the block, this function changes wc->stage to
7307  * UPDATE_BACKREF. if the block is shared and there is no
7308  * need to update back, this function drops the reference
7309  * to the block.
7310  *
7311  * NOTE: return value 1 means we should stop walking down.
7312  */
7313 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7314                                  struct btrfs_root *root,
7315                                  struct btrfs_path *path,
7316                                  struct walk_control *wc, int *lookup_info)
7317 {
7318         u64 bytenr;
7319         u64 generation;
7320         u64 parent;
7321         u32 blocksize;
7322         struct btrfs_key key;
7323         struct extent_buffer *next;
7324         int level = wc->level;
7325         int reada = 0;
7326         int ret = 0;
7327
7328         generation = btrfs_node_ptr_generation(path->nodes[level],
7329                                                path->slots[level]);
7330         /*
7331          * if the lower level block was created before the snapshot
7332          * was created, we know there is no need to update back refs
7333          * for the subtree
7334          */
7335         if (wc->stage == UPDATE_BACKREF &&
7336             generation <= root->root_key.offset) {
7337                 *lookup_info = 1;
7338                 return 1;
7339         }
7340
7341         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7342         blocksize = btrfs_level_size(root, level - 1);
7343
7344         next = btrfs_find_tree_block(root, bytenr, blocksize);
7345         if (!next) {
7346                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7347                 if (!next)
7348                         return -ENOMEM;
7349                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7350                                                level - 1);
7351                 reada = 1;
7352         }
7353         btrfs_tree_lock(next);
7354         btrfs_set_lock_blocking(next);
7355
7356         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7357                                        &wc->refs[level - 1],
7358                                        &wc->flags[level - 1]);
7359         if (ret < 0) {
7360                 btrfs_tree_unlock(next);
7361                 return ret;
7362         }
7363
7364         if (unlikely(wc->refs[level - 1] == 0)) {
7365                 btrfs_err(root->fs_info, "Missing references.");
7366                 BUG();
7367         }
7368         *lookup_info = 0;
7369
7370         if (wc->stage == DROP_REFERENCE) {
7371                 if (wc->refs[level - 1] > 1) {
7372                         if (level == 1 &&
7373                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7374                                 goto skip;
7375
7376                         if (!wc->update_ref ||
7377                             generation <= root->root_key.offset)
7378                                 goto skip;
7379
7380                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7381                                               path->slots[level]);
7382                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7383                         if (ret < 0)
7384                                 goto skip;
7385
7386                         wc->stage = UPDATE_BACKREF;
7387                         wc->shared_level = level - 1;
7388                 }
7389         } else {
7390                 if (level == 1 &&
7391                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7392                         goto skip;
7393         }
7394
7395         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7396                 btrfs_tree_unlock(next);
7397                 free_extent_buffer(next);
7398                 next = NULL;
7399                 *lookup_info = 1;
7400         }
7401
7402         if (!next) {
7403                 if (reada && level == 1)
7404                         reada_walk_down(trans, root, wc, path);
7405                 next = read_tree_block(root, bytenr, blocksize, generation);
7406                 if (!next || !extent_buffer_uptodate(next)) {
7407                         free_extent_buffer(next);
7408                         return -EIO;
7409                 }
7410                 btrfs_tree_lock(next);
7411                 btrfs_set_lock_blocking(next);
7412         }
7413
7414         level--;
7415         BUG_ON(level != btrfs_header_level(next));
7416         path->nodes[level] = next;
7417         path->slots[level] = 0;
7418         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7419         wc->level = level;
7420         if (wc->level == 1)
7421                 wc->reada_slot = 0;
7422         return 0;
7423 skip:
7424         wc->refs[level - 1] = 0;
7425         wc->flags[level - 1] = 0;
7426         if (wc->stage == DROP_REFERENCE) {
7427                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7428                         parent = path->nodes[level]->start;
7429                 } else {
7430                         BUG_ON(root->root_key.objectid !=
7431                                btrfs_header_owner(path->nodes[level]));
7432                         parent = 0;
7433                 }
7434
7435                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7436                                 root->root_key.objectid, level - 1, 0, 0);
7437                 BUG_ON(ret); /* -ENOMEM */
7438         }
7439         btrfs_tree_unlock(next);
7440         free_extent_buffer(next);
7441         *lookup_info = 1;
7442         return 1;
7443 }
7444
7445 /*
7446  * helper to process tree block while walking up the tree.
7447  *
7448  * when wc->stage == DROP_REFERENCE, this function drops
7449  * reference count on the block.
7450  *
7451  * when wc->stage == UPDATE_BACKREF, this function changes
7452  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7453  * to UPDATE_BACKREF previously while processing the block.
7454  *
7455  * NOTE: return value 1 means we should stop walking up.
7456  */
7457 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7458                                  struct btrfs_root *root,
7459                                  struct btrfs_path *path,
7460                                  struct walk_control *wc)
7461 {
7462         int ret;
7463         int level = wc->level;
7464         struct extent_buffer *eb = path->nodes[level];
7465         u64 parent = 0;
7466
7467         if (wc->stage == UPDATE_BACKREF) {
7468                 BUG_ON(wc->shared_level < level);
7469                 if (level < wc->shared_level)
7470                         goto out;
7471
7472                 ret = find_next_key(path, level + 1, &wc->update_progress);
7473                 if (ret > 0)
7474                         wc->update_ref = 0;
7475
7476                 wc->stage = DROP_REFERENCE;
7477                 wc->shared_level = -1;
7478                 path->slots[level] = 0;
7479
7480                 /*
7481                  * check reference count again if the block isn't locked.
7482                  * we should start walking down the tree again if reference
7483                  * count is one.
7484                  */
7485                 if (!path->locks[level]) {
7486                         BUG_ON(level == 0);
7487                         btrfs_tree_lock(eb);
7488                         btrfs_set_lock_blocking(eb);
7489                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7490
7491                         ret = btrfs_lookup_extent_info(trans, root,
7492                                                        eb->start, level, 1,
7493                                                        &wc->refs[level],
7494                                                        &wc->flags[level]);
7495                         if (ret < 0) {
7496                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7497                                 path->locks[level] = 0;
7498                                 return ret;
7499                         }
7500                         BUG_ON(wc->refs[level] == 0);
7501                         if (wc->refs[level] == 1) {
7502                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7503                                 path->locks[level] = 0;
7504                                 return 1;
7505                         }
7506                 }
7507         }
7508
7509         /* wc->stage == DROP_REFERENCE */
7510         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7511
7512         if (wc->refs[level] == 1) {
7513                 if (level == 0) {
7514                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7515                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7516                                                     wc->for_reloc);
7517                         else
7518                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7519                                                     wc->for_reloc);
7520                         BUG_ON(ret); /* -ENOMEM */
7521                 }
7522                 /* make block locked assertion in clean_tree_block happy */
7523                 if (!path->locks[level] &&
7524                     btrfs_header_generation(eb) == trans->transid) {
7525                         btrfs_tree_lock(eb);
7526                         btrfs_set_lock_blocking(eb);
7527                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7528                 }
7529                 clean_tree_block(trans, root, eb);
7530         }
7531
7532         if (eb == root->node) {
7533                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7534                         parent = eb->start;
7535                 else
7536                         BUG_ON(root->root_key.objectid !=
7537                                btrfs_header_owner(eb));
7538         } else {
7539                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7540                         parent = path->nodes[level + 1]->start;
7541                 else
7542                         BUG_ON(root->root_key.objectid !=
7543                                btrfs_header_owner(path->nodes[level + 1]));
7544         }
7545
7546         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7547 out:
7548         wc->refs[level] = 0;
7549         wc->flags[level] = 0;
7550         return 0;
7551 }
7552
7553 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7554                                    struct btrfs_root *root,
7555                                    struct btrfs_path *path,
7556                                    struct walk_control *wc)
7557 {
7558         int level = wc->level;
7559         int lookup_info = 1;
7560         int ret;
7561
7562         while (level >= 0) {
7563                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7564                 if (ret > 0)
7565                         break;
7566
7567                 if (level == 0)
7568                         break;
7569
7570                 if (path->slots[level] >=
7571                     btrfs_header_nritems(path->nodes[level]))
7572                         break;
7573
7574                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7575                 if (ret > 0) {
7576                         path->slots[level]++;
7577                         continue;
7578                 } else if (ret < 0)
7579                         return ret;
7580                 level = wc->level;
7581         }
7582         return 0;
7583 }
7584
7585 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7586                                  struct btrfs_root *root,
7587                                  struct btrfs_path *path,
7588                                  struct walk_control *wc, int max_level)
7589 {
7590         int level = wc->level;
7591         int ret;
7592
7593         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7594         while (level < max_level && path->nodes[level]) {
7595                 wc->level = level;
7596                 if (path->slots[level] + 1 <
7597                     btrfs_header_nritems(path->nodes[level])) {
7598                         path->slots[level]++;
7599                         return 0;
7600                 } else {
7601                         ret = walk_up_proc(trans, root, path, wc);
7602                         if (ret > 0)
7603                                 return 0;
7604
7605                         if (path->locks[level]) {
7606                                 btrfs_tree_unlock_rw(path->nodes[level],
7607                                                      path->locks[level]);
7608                                 path->locks[level] = 0;
7609                         }
7610                         free_extent_buffer(path->nodes[level]);
7611                         path->nodes[level] = NULL;
7612                         level++;
7613                 }
7614         }
7615         return 1;
7616 }
7617
7618 /*
7619  * drop a subvolume tree.
7620  *
7621  * this function traverses the tree freeing any blocks that only
7622  * referenced by the tree.
7623  *
7624  * when a shared tree block is found. this function decreases its
7625  * reference count by one. if update_ref is true, this function
7626  * also make sure backrefs for the shared block and all lower level
7627  * blocks are properly updated.
7628  *
7629  * If called with for_reloc == 0, may exit early with -EAGAIN
7630  */
7631 int btrfs_drop_snapshot(struct btrfs_root *root,
7632                          struct btrfs_block_rsv *block_rsv, int update_ref,
7633                          int for_reloc)
7634 {
7635         struct btrfs_path *path;
7636         struct btrfs_trans_handle *trans;
7637         struct btrfs_root *tree_root = root->fs_info->tree_root;
7638         struct btrfs_root_item *root_item = &root->root_item;
7639         struct walk_control *wc;
7640         struct btrfs_key key;
7641         int err = 0;
7642         int ret;
7643         int level;
7644         bool root_dropped = false;
7645
7646         path = btrfs_alloc_path();
7647         if (!path) {
7648                 err = -ENOMEM;
7649                 goto out;
7650         }
7651
7652         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7653         if (!wc) {
7654                 btrfs_free_path(path);
7655                 err = -ENOMEM;
7656                 goto out;
7657         }
7658
7659         trans = btrfs_start_transaction(tree_root, 0);
7660         if (IS_ERR(trans)) {
7661                 err = PTR_ERR(trans);
7662                 goto out_free;
7663         }
7664
7665         if (block_rsv)
7666                 trans->block_rsv = block_rsv;
7667
7668         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7669                 level = btrfs_header_level(root->node);
7670                 path->nodes[level] = btrfs_lock_root_node(root);
7671                 btrfs_set_lock_blocking(path->nodes[level]);
7672                 path->slots[level] = 0;
7673                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7674                 memset(&wc->update_progress, 0,
7675                        sizeof(wc->update_progress));
7676         } else {
7677                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7678                 memcpy(&wc->update_progress, &key,
7679                        sizeof(wc->update_progress));
7680
7681                 level = root_item->drop_level;
7682                 BUG_ON(level == 0);
7683                 path->lowest_level = level;
7684                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7685                 path->lowest_level = 0;
7686                 if (ret < 0) {
7687                         err = ret;
7688                         goto out_end_trans;
7689                 }
7690                 WARN_ON(ret > 0);
7691
7692                 /*
7693                  * unlock our path, this is safe because only this
7694                  * function is allowed to delete this snapshot
7695                  */
7696                 btrfs_unlock_up_safe(path, 0);
7697
7698                 level = btrfs_header_level(root->node);
7699                 while (1) {
7700                         btrfs_tree_lock(path->nodes[level]);
7701                         btrfs_set_lock_blocking(path->nodes[level]);
7702                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7703
7704                         ret = btrfs_lookup_extent_info(trans, root,
7705                                                 path->nodes[level]->start,
7706                                                 level, 1, &wc->refs[level],
7707                                                 &wc->flags[level]);
7708                         if (ret < 0) {
7709                                 err = ret;
7710                                 goto out_end_trans;
7711                         }
7712                         BUG_ON(wc->refs[level] == 0);
7713
7714                         if (level == root_item->drop_level)
7715                                 break;
7716
7717                         btrfs_tree_unlock(path->nodes[level]);
7718                         path->locks[level] = 0;
7719                         WARN_ON(wc->refs[level] != 1);
7720                         level--;
7721                 }
7722         }
7723
7724         wc->level = level;
7725         wc->shared_level = -1;
7726         wc->stage = DROP_REFERENCE;
7727         wc->update_ref = update_ref;
7728         wc->keep_locks = 0;
7729         wc->for_reloc = for_reloc;
7730         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7731
7732         while (1) {
7733
7734                 ret = walk_down_tree(trans, root, path, wc);
7735                 if (ret < 0) {
7736                         err = ret;
7737                         break;
7738                 }
7739
7740                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7741                 if (ret < 0) {
7742                         err = ret;
7743                         break;
7744                 }
7745
7746                 if (ret > 0) {
7747                         BUG_ON(wc->stage != DROP_REFERENCE);
7748                         break;
7749                 }
7750
7751                 if (wc->stage == DROP_REFERENCE) {
7752                         level = wc->level;
7753                         btrfs_node_key(path->nodes[level],
7754                                        &root_item->drop_progress,
7755                                        path->slots[level]);
7756                         root_item->drop_level = level;
7757                 }
7758
7759                 BUG_ON(wc->level == 0);
7760                 if (btrfs_should_end_transaction(trans, tree_root) ||
7761                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7762                         ret = btrfs_update_root(trans, tree_root,
7763                                                 &root->root_key,
7764                                                 root_item);
7765                         if (ret) {
7766                                 btrfs_abort_transaction(trans, tree_root, ret);
7767                                 err = ret;
7768                                 goto out_end_trans;
7769                         }
7770
7771                         btrfs_end_transaction_throttle(trans, tree_root);
7772                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7773                                 pr_debug("BTRFS: drop snapshot early exit\n");
7774                                 err = -EAGAIN;
7775                                 goto out_free;
7776                         }
7777
7778                         trans = btrfs_start_transaction(tree_root, 0);
7779                         if (IS_ERR(trans)) {
7780                                 err = PTR_ERR(trans);
7781                                 goto out_free;
7782                         }
7783                         if (block_rsv)
7784                                 trans->block_rsv = block_rsv;
7785                 }
7786         }
7787         btrfs_release_path(path);
7788         if (err)
7789                 goto out_end_trans;
7790
7791         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7792         if (ret) {
7793                 btrfs_abort_transaction(trans, tree_root, ret);
7794                 goto out_end_trans;
7795         }
7796
7797         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7798                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7799                                       NULL, NULL);
7800                 if (ret < 0) {
7801                         btrfs_abort_transaction(trans, tree_root, ret);
7802                         err = ret;
7803                         goto out_end_trans;
7804                 } else if (ret > 0) {
7805                         /* if we fail to delete the orphan item this time
7806                          * around, it'll get picked up the next time.
7807                          *
7808                          * The most common failure here is just -ENOENT.
7809                          */
7810                         btrfs_del_orphan_item(trans, tree_root,
7811                                               root->root_key.objectid);
7812                 }
7813         }
7814
7815         if (root->in_radix) {
7816                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7817         } else {
7818                 free_extent_buffer(root->node);
7819                 free_extent_buffer(root->commit_root);
7820                 btrfs_put_fs_root(root);
7821         }
7822         root_dropped = true;
7823 out_end_trans:
7824         btrfs_end_transaction_throttle(trans, tree_root);
7825 out_free:
7826         kfree(wc);
7827         btrfs_free_path(path);
7828 out:
7829         /*
7830          * So if we need to stop dropping the snapshot for whatever reason we
7831          * need to make sure to add it back to the dead root list so that we
7832          * keep trying to do the work later.  This also cleans up roots if we
7833          * don't have it in the radix (like when we recover after a power fail
7834          * or unmount) so we don't leak memory.
7835          */
7836         if (!for_reloc && root_dropped == false)
7837                 btrfs_add_dead_root(root);
7838         if (err)
7839                 btrfs_std_error(root->fs_info, err);
7840         return err;
7841 }
7842
7843 /*
7844  * drop subtree rooted at tree block 'node'.
7845  *
7846  * NOTE: this function will unlock and release tree block 'node'
7847  * only used by relocation code
7848  */
7849 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7850                         struct btrfs_root *root,
7851                         struct extent_buffer *node,
7852                         struct extent_buffer *parent)
7853 {
7854         struct btrfs_path *path;
7855         struct walk_control *wc;
7856         int level;
7857         int parent_level;
7858         int ret = 0;
7859         int wret;
7860
7861         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7862
7863         path = btrfs_alloc_path();
7864         if (!path)
7865                 return -ENOMEM;
7866
7867         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7868         if (!wc) {
7869                 btrfs_free_path(path);
7870                 return -ENOMEM;
7871         }
7872
7873         btrfs_assert_tree_locked(parent);
7874         parent_level = btrfs_header_level(parent);
7875         extent_buffer_get(parent);
7876         path->nodes[parent_level] = parent;
7877         path->slots[parent_level] = btrfs_header_nritems(parent);
7878
7879         btrfs_assert_tree_locked(node);
7880         level = btrfs_header_level(node);
7881         path->nodes[level] = node;
7882         path->slots[level] = 0;
7883         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7884
7885         wc->refs[parent_level] = 1;
7886         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7887         wc->level = level;
7888         wc->shared_level = -1;
7889         wc->stage = DROP_REFERENCE;
7890         wc->update_ref = 0;
7891         wc->keep_locks = 1;
7892         wc->for_reloc = 1;
7893         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7894
7895         while (1) {
7896                 wret = walk_down_tree(trans, root, path, wc);
7897                 if (wret < 0) {
7898                         ret = wret;
7899                         break;
7900                 }
7901
7902                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7903                 if (wret < 0)
7904                         ret = wret;
7905                 if (wret != 0)
7906                         break;
7907         }
7908
7909         kfree(wc);
7910         btrfs_free_path(path);
7911         return ret;
7912 }
7913
7914 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7915 {
7916         u64 num_devices;
7917         u64 stripped;
7918
7919         /*
7920          * if restripe for this chunk_type is on pick target profile and
7921          * return, otherwise do the usual balance
7922          */
7923         stripped = get_restripe_target(root->fs_info, flags);
7924         if (stripped)
7925                 return extended_to_chunk(stripped);
7926
7927         /*
7928          * we add in the count of missing devices because we want
7929          * to make sure that any RAID levels on a degraded FS
7930          * continue to be honored.
7931          */
7932         num_devices = root->fs_info->fs_devices->rw_devices +
7933                 root->fs_info->fs_devices->missing_devices;
7934
7935         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7936                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7937                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7938
7939         if (num_devices == 1) {
7940                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7941                 stripped = flags & ~stripped;
7942
7943                 /* turn raid0 into single device chunks */
7944                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7945                         return stripped;
7946
7947                 /* turn mirroring into duplication */
7948                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7949                              BTRFS_BLOCK_GROUP_RAID10))
7950                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7951         } else {
7952                 /* they already had raid on here, just return */
7953                 if (flags & stripped)
7954                         return flags;
7955
7956                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7957                 stripped = flags & ~stripped;
7958
7959                 /* switch duplicated blocks with raid1 */
7960                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7961                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7962
7963                 /* this is drive concat, leave it alone */
7964         }
7965
7966         return flags;
7967 }
7968
7969 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7970 {
7971         struct btrfs_space_info *sinfo = cache->space_info;
7972         u64 num_bytes;
7973         u64 min_allocable_bytes;
7974         int ret = -ENOSPC;
7975
7976
7977         /*
7978          * We need some metadata space and system metadata space for
7979          * allocating chunks in some corner cases until we force to set
7980          * it to be readonly.
7981          */
7982         if ((sinfo->flags &
7983              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7984             !force)
7985                 min_allocable_bytes = 1 * 1024 * 1024;
7986         else
7987                 min_allocable_bytes = 0;
7988
7989         spin_lock(&sinfo->lock);
7990         spin_lock(&cache->lock);
7991
7992         if (cache->ro) {
7993                 ret = 0;
7994                 goto out;
7995         }
7996
7997         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7998                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7999
8000         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8001             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8002             min_allocable_bytes <= sinfo->total_bytes) {
8003                 sinfo->bytes_readonly += num_bytes;
8004                 cache->ro = 1;
8005                 ret = 0;
8006         }
8007 out:
8008         spin_unlock(&cache->lock);
8009         spin_unlock(&sinfo->lock);
8010         return ret;
8011 }
8012
8013 int btrfs_set_block_group_ro(struct btrfs_root *root,
8014                              struct btrfs_block_group_cache *cache)
8015
8016 {
8017         struct btrfs_trans_handle *trans;
8018         u64 alloc_flags;
8019         int ret;
8020
8021         BUG_ON(cache->ro);
8022
8023         trans = btrfs_join_transaction(root);
8024         if (IS_ERR(trans))
8025                 return PTR_ERR(trans);
8026
8027         alloc_flags = update_block_group_flags(root, cache->flags);
8028         if (alloc_flags != cache->flags) {
8029                 ret = do_chunk_alloc(trans, root, alloc_flags,
8030                                      CHUNK_ALLOC_FORCE);
8031                 if (ret < 0)
8032                         goto out;
8033         }
8034
8035         ret = set_block_group_ro(cache, 0);
8036         if (!ret)
8037                 goto out;
8038         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8039         ret = do_chunk_alloc(trans, root, alloc_flags,
8040                              CHUNK_ALLOC_FORCE);
8041         if (ret < 0)
8042                 goto out;
8043         ret = set_block_group_ro(cache, 0);
8044 out:
8045         btrfs_end_transaction(trans, root);
8046         return ret;
8047 }
8048
8049 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8050                             struct btrfs_root *root, u64 type)
8051 {
8052         u64 alloc_flags = get_alloc_profile(root, type);
8053         return do_chunk_alloc(trans, root, alloc_flags,
8054                               CHUNK_ALLOC_FORCE);
8055 }
8056
8057 /*
8058  * helper to account the unused space of all the readonly block group in the
8059  * list. takes mirrors into account.
8060  */
8061 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
8062 {
8063         struct btrfs_block_group_cache *block_group;
8064         u64 free_bytes = 0;
8065         int factor;
8066
8067         list_for_each_entry(block_group, groups_list, list) {
8068                 spin_lock(&block_group->lock);
8069
8070                 if (!block_group->ro) {
8071                         spin_unlock(&block_group->lock);
8072                         continue;
8073                 }
8074
8075                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8076                                           BTRFS_BLOCK_GROUP_RAID10 |
8077                                           BTRFS_BLOCK_GROUP_DUP))
8078                         factor = 2;
8079                 else
8080                         factor = 1;
8081
8082                 free_bytes += (block_group->key.offset -
8083                                btrfs_block_group_used(&block_group->item)) *
8084                                factor;
8085
8086                 spin_unlock(&block_group->lock);
8087         }
8088
8089         return free_bytes;
8090 }
8091
8092 /*
8093  * helper to account the unused space of all the readonly block group in the
8094  * space_info. takes mirrors into account.
8095  */
8096 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8097 {
8098         int i;
8099         u64 free_bytes = 0;
8100
8101         spin_lock(&sinfo->lock);
8102
8103         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
8104                 if (!list_empty(&sinfo->block_groups[i]))
8105                         free_bytes += __btrfs_get_ro_block_group_free_space(
8106                                                 &sinfo->block_groups[i]);
8107
8108         spin_unlock(&sinfo->lock);
8109
8110         return free_bytes;
8111 }
8112
8113 void btrfs_set_block_group_rw(struct btrfs_root *root,
8114                               struct btrfs_block_group_cache *cache)
8115 {
8116         struct btrfs_space_info *sinfo = cache->space_info;
8117         u64 num_bytes;
8118
8119         BUG_ON(!cache->ro);
8120
8121         spin_lock(&sinfo->lock);
8122         spin_lock(&cache->lock);
8123         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8124                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8125         sinfo->bytes_readonly -= num_bytes;
8126         cache->ro = 0;
8127         spin_unlock(&cache->lock);
8128         spin_unlock(&sinfo->lock);
8129 }
8130
8131 /*
8132  * checks to see if its even possible to relocate this block group.
8133  *
8134  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8135  * ok to go ahead and try.
8136  */
8137 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8138 {
8139         struct btrfs_block_group_cache *block_group;
8140         struct btrfs_space_info *space_info;
8141         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8142         struct btrfs_device *device;
8143         struct btrfs_trans_handle *trans;
8144         u64 min_free;
8145         u64 dev_min = 1;
8146         u64 dev_nr = 0;
8147         u64 target;
8148         int index;
8149         int full = 0;
8150         int ret = 0;
8151
8152         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8153
8154         /* odd, couldn't find the block group, leave it alone */
8155         if (!block_group)
8156                 return -1;
8157
8158         min_free = btrfs_block_group_used(&block_group->item);
8159
8160         /* no bytes used, we're good */
8161         if (!min_free)
8162                 goto out;
8163
8164         space_info = block_group->space_info;
8165         spin_lock(&space_info->lock);
8166
8167         full = space_info->full;
8168
8169         /*
8170          * if this is the last block group we have in this space, we can't
8171          * relocate it unless we're able to allocate a new chunk below.
8172          *
8173          * Otherwise, we need to make sure we have room in the space to handle
8174          * all of the extents from this block group.  If we can, we're good
8175          */
8176         if ((space_info->total_bytes != block_group->key.offset) &&
8177             (space_info->bytes_used + space_info->bytes_reserved +
8178              space_info->bytes_pinned + space_info->bytes_readonly +
8179              min_free < space_info->total_bytes)) {
8180                 spin_unlock(&space_info->lock);
8181                 goto out;
8182         }
8183         spin_unlock(&space_info->lock);
8184
8185         /*
8186          * ok we don't have enough space, but maybe we have free space on our
8187          * devices to allocate new chunks for relocation, so loop through our
8188          * alloc devices and guess if we have enough space.  if this block
8189          * group is going to be restriped, run checks against the target
8190          * profile instead of the current one.
8191          */
8192         ret = -1;
8193
8194         /*
8195          * index:
8196          *      0: raid10
8197          *      1: raid1
8198          *      2: dup
8199          *      3: raid0
8200          *      4: single
8201          */
8202         target = get_restripe_target(root->fs_info, block_group->flags);
8203         if (target) {
8204                 index = __get_raid_index(extended_to_chunk(target));
8205         } else {
8206                 /*
8207                  * this is just a balance, so if we were marked as full
8208                  * we know there is no space for a new chunk
8209                  */
8210                 if (full)
8211                         goto out;
8212
8213                 index = get_block_group_index(block_group);
8214         }
8215
8216         if (index == BTRFS_RAID_RAID10) {
8217                 dev_min = 4;
8218                 /* Divide by 2 */
8219                 min_free >>= 1;
8220         } else if (index == BTRFS_RAID_RAID1) {
8221                 dev_min = 2;
8222         } else if (index == BTRFS_RAID_DUP) {
8223                 /* Multiply by 2 */
8224                 min_free <<= 1;
8225         } else if (index == BTRFS_RAID_RAID0) {
8226                 dev_min = fs_devices->rw_devices;
8227                 do_div(min_free, dev_min);
8228         }
8229
8230         /* We need to do this so that we can look at pending chunks */
8231         trans = btrfs_join_transaction(root);
8232         if (IS_ERR(trans)) {
8233                 ret = PTR_ERR(trans);
8234                 goto out;
8235         }
8236
8237         mutex_lock(&root->fs_info->chunk_mutex);
8238         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8239                 u64 dev_offset;
8240
8241                 /*
8242                  * check to make sure we can actually find a chunk with enough
8243                  * space to fit our block group in.
8244                  */
8245                 if (device->total_bytes > device->bytes_used + min_free &&
8246                     !device->is_tgtdev_for_dev_replace) {
8247                         ret = find_free_dev_extent(trans, device, min_free,
8248                                                    &dev_offset, NULL);
8249                         if (!ret)
8250                                 dev_nr++;
8251
8252                         if (dev_nr >= dev_min)
8253                                 break;
8254
8255                         ret = -1;
8256                 }
8257         }
8258         mutex_unlock(&root->fs_info->chunk_mutex);
8259         btrfs_end_transaction(trans, root);
8260 out:
8261         btrfs_put_block_group(block_group);
8262         return ret;
8263 }
8264
8265 static int find_first_block_group(struct btrfs_root *root,
8266                 struct btrfs_path *path, struct btrfs_key *key)
8267 {
8268         int ret = 0;
8269         struct btrfs_key found_key;
8270         struct extent_buffer *leaf;
8271         int slot;
8272
8273         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8274         if (ret < 0)
8275                 goto out;
8276
8277         while (1) {
8278                 slot = path->slots[0];
8279                 leaf = path->nodes[0];
8280                 if (slot >= btrfs_header_nritems(leaf)) {
8281                         ret = btrfs_next_leaf(root, path);
8282                         if (ret == 0)
8283                                 continue;
8284                         if (ret < 0)
8285                                 goto out;
8286                         break;
8287                 }
8288                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8289
8290                 if (found_key.objectid >= key->objectid &&
8291                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8292                         ret = 0;
8293                         goto out;
8294                 }
8295                 path->slots[0]++;
8296         }
8297 out:
8298         return ret;
8299 }
8300
8301 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8302 {
8303         struct btrfs_block_group_cache *block_group;
8304         u64 last = 0;
8305
8306         while (1) {
8307                 struct inode *inode;
8308
8309                 block_group = btrfs_lookup_first_block_group(info, last);
8310                 while (block_group) {
8311                         spin_lock(&block_group->lock);
8312                         if (block_group->iref)
8313                                 break;
8314                         spin_unlock(&block_group->lock);
8315                         block_group = next_block_group(info->tree_root,
8316                                                        block_group);
8317                 }
8318                 if (!block_group) {
8319                         if (last == 0)
8320                                 break;
8321                         last = 0;
8322                         continue;
8323                 }
8324
8325                 inode = block_group->inode;
8326                 block_group->iref = 0;
8327                 block_group->inode = NULL;
8328                 spin_unlock(&block_group->lock);
8329                 iput(inode);
8330                 last = block_group->key.objectid + block_group->key.offset;
8331                 btrfs_put_block_group(block_group);
8332         }
8333 }
8334
8335 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8336 {
8337         struct btrfs_block_group_cache *block_group;
8338         struct btrfs_space_info *space_info;
8339         struct btrfs_caching_control *caching_ctl;
8340         struct rb_node *n;
8341
8342         down_write(&info->extent_commit_sem);
8343         while (!list_empty(&info->caching_block_groups)) {
8344                 caching_ctl = list_entry(info->caching_block_groups.next,
8345                                          struct btrfs_caching_control, list);
8346                 list_del(&caching_ctl->list);
8347                 put_caching_control(caching_ctl);
8348         }
8349         up_write(&info->extent_commit_sem);
8350
8351         spin_lock(&info->block_group_cache_lock);
8352         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8353                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8354                                        cache_node);
8355                 rb_erase(&block_group->cache_node,
8356                          &info->block_group_cache_tree);
8357                 spin_unlock(&info->block_group_cache_lock);
8358
8359                 down_write(&block_group->space_info->groups_sem);
8360                 list_del(&block_group->list);
8361                 up_write(&block_group->space_info->groups_sem);
8362
8363                 if (block_group->cached == BTRFS_CACHE_STARTED)
8364                         wait_block_group_cache_done(block_group);
8365
8366                 /*
8367                  * We haven't cached this block group, which means we could
8368                  * possibly have excluded extents on this block group.
8369                  */
8370                 if (block_group->cached == BTRFS_CACHE_NO ||
8371                     block_group->cached == BTRFS_CACHE_ERROR)
8372                         free_excluded_extents(info->extent_root, block_group);
8373
8374                 btrfs_remove_free_space_cache(block_group);
8375                 btrfs_put_block_group(block_group);
8376
8377                 spin_lock(&info->block_group_cache_lock);
8378         }
8379         spin_unlock(&info->block_group_cache_lock);
8380
8381         /* now that all the block groups are freed, go through and
8382          * free all the space_info structs.  This is only called during
8383          * the final stages of unmount, and so we know nobody is
8384          * using them.  We call synchronize_rcu() once before we start,
8385          * just to be on the safe side.
8386          */
8387         synchronize_rcu();
8388
8389         release_global_block_rsv(info);
8390
8391         while (!list_empty(&info->space_info)) {
8392                 int i;
8393
8394                 space_info = list_entry(info->space_info.next,
8395                                         struct btrfs_space_info,
8396                                         list);
8397                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8398                         if (WARN_ON(space_info->bytes_pinned > 0 ||
8399                             space_info->bytes_reserved > 0 ||
8400                             space_info->bytes_may_use > 0)) {
8401                                 dump_space_info(space_info, 0, 0);
8402                         }
8403                 }
8404                 list_del(&space_info->list);
8405                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
8406                         struct kobject *kobj;
8407                         kobj = &space_info->block_group_kobjs[i];
8408                         if (kobj->parent) {
8409                                 kobject_del(kobj);
8410                                 kobject_put(kobj);
8411                         }
8412                 }
8413                 kobject_del(&space_info->kobj);
8414                 kobject_put(&space_info->kobj);
8415         }
8416         return 0;
8417 }
8418
8419 static void __link_block_group(struct btrfs_space_info *space_info,
8420                                struct btrfs_block_group_cache *cache)
8421 {
8422         int index = get_block_group_index(cache);
8423
8424         down_write(&space_info->groups_sem);
8425         if (list_empty(&space_info->block_groups[index])) {
8426                 struct kobject *kobj = &space_info->block_group_kobjs[index];
8427                 int ret;
8428
8429                 kobject_get(&space_info->kobj); /* put in release */
8430                 ret = kobject_add(kobj, &space_info->kobj, "%s",
8431                                   get_raid_name(index));
8432                 if (ret) {
8433                         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
8434                         kobject_put(&space_info->kobj);
8435                 }
8436         }
8437         list_add_tail(&cache->list, &space_info->block_groups[index]);
8438         up_write(&space_info->groups_sem);
8439 }
8440
8441 int btrfs_read_block_groups(struct btrfs_root *root)
8442 {
8443         struct btrfs_path *path;
8444         int ret;
8445         struct btrfs_block_group_cache *cache;
8446         struct btrfs_fs_info *info = root->fs_info;
8447         struct btrfs_space_info *space_info;
8448         struct btrfs_key key;
8449         struct btrfs_key found_key;
8450         struct extent_buffer *leaf;
8451         int need_clear = 0;
8452         u64 cache_gen;
8453
8454         root = info->extent_root;
8455         key.objectid = 0;
8456         key.offset = 0;
8457         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8458         path = btrfs_alloc_path();
8459         if (!path)
8460                 return -ENOMEM;
8461         path->reada = 1;
8462
8463         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8464         if (btrfs_test_opt(root, SPACE_CACHE) &&
8465             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8466                 need_clear = 1;
8467         if (btrfs_test_opt(root, CLEAR_CACHE))
8468                 need_clear = 1;
8469
8470         while (1) {
8471                 ret = find_first_block_group(root, path, &key);
8472                 if (ret > 0)
8473                         break;
8474                 if (ret != 0)
8475                         goto error;
8476                 leaf = path->nodes[0];
8477                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8478                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8479                 if (!cache) {
8480                         ret = -ENOMEM;
8481                         goto error;
8482                 }
8483                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8484                                                 GFP_NOFS);
8485                 if (!cache->free_space_ctl) {
8486                         kfree(cache);
8487                         ret = -ENOMEM;
8488                         goto error;
8489                 }
8490
8491                 atomic_set(&cache->count, 1);
8492                 spin_lock_init(&cache->lock);
8493                 cache->fs_info = info;
8494                 INIT_LIST_HEAD(&cache->list);
8495                 INIT_LIST_HEAD(&cache->cluster_list);
8496
8497                 if (need_clear) {
8498                         /*
8499                          * When we mount with old space cache, we need to
8500                          * set BTRFS_DC_CLEAR and set dirty flag.
8501                          *
8502                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8503                          *    truncate the old free space cache inode and
8504                          *    setup a new one.
8505                          * b) Setting 'dirty flag' makes sure that we flush
8506                          *    the new space cache info onto disk.
8507                          */
8508                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8509                         if (btrfs_test_opt(root, SPACE_CACHE))
8510                                 cache->dirty = 1;
8511                 }
8512
8513                 read_extent_buffer(leaf, &cache->item,
8514                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8515                                    sizeof(cache->item));
8516                 memcpy(&cache->key, &found_key, sizeof(found_key));
8517
8518                 key.objectid = found_key.objectid + found_key.offset;
8519                 btrfs_release_path(path);
8520                 cache->flags = btrfs_block_group_flags(&cache->item);
8521                 cache->sectorsize = root->sectorsize;
8522                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8523                                                &root->fs_info->mapping_tree,
8524                                                found_key.objectid);
8525                 btrfs_init_free_space_ctl(cache);
8526
8527                 /*
8528                  * We need to exclude the super stripes now so that the space
8529                  * info has super bytes accounted for, otherwise we'll think
8530                  * we have more space than we actually do.
8531                  */
8532                 ret = exclude_super_stripes(root, cache);
8533                 if (ret) {
8534                         /*
8535                          * We may have excluded something, so call this just in
8536                          * case.
8537                          */
8538                         free_excluded_extents(root, cache);
8539                         kfree(cache->free_space_ctl);
8540                         kfree(cache);
8541                         goto error;
8542                 }
8543
8544                 /*
8545                  * check for two cases, either we are full, and therefore
8546                  * don't need to bother with the caching work since we won't
8547                  * find any space, or we are empty, and we can just add all
8548                  * the space in and be done with it.  This saves us _alot_ of
8549                  * time, particularly in the full case.
8550                  */
8551                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8552                         cache->last_byte_to_unpin = (u64)-1;
8553                         cache->cached = BTRFS_CACHE_FINISHED;
8554                         free_excluded_extents(root, cache);
8555                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8556                         cache->last_byte_to_unpin = (u64)-1;
8557                         cache->cached = BTRFS_CACHE_FINISHED;
8558                         add_new_free_space(cache, root->fs_info,
8559                                            found_key.objectid,
8560                                            found_key.objectid +
8561                                            found_key.offset);
8562                         free_excluded_extents(root, cache);
8563                 }
8564
8565                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8566                 if (ret) {
8567                         btrfs_remove_free_space_cache(cache);
8568                         btrfs_put_block_group(cache);
8569                         goto error;
8570                 }
8571
8572                 ret = update_space_info(info, cache->flags, found_key.offset,
8573                                         btrfs_block_group_used(&cache->item),
8574                                         &space_info);
8575                 if (ret) {
8576                         btrfs_remove_free_space_cache(cache);
8577                         spin_lock(&info->block_group_cache_lock);
8578                         rb_erase(&cache->cache_node,
8579                                  &info->block_group_cache_tree);
8580                         spin_unlock(&info->block_group_cache_lock);
8581                         btrfs_put_block_group(cache);
8582                         goto error;
8583                 }
8584
8585                 cache->space_info = space_info;
8586                 spin_lock(&cache->space_info->lock);
8587                 cache->space_info->bytes_readonly += cache->bytes_super;
8588                 spin_unlock(&cache->space_info->lock);
8589
8590                 __link_block_group(space_info, cache);
8591
8592                 set_avail_alloc_bits(root->fs_info, cache->flags);
8593                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8594                         set_block_group_ro(cache, 1);
8595         }
8596
8597         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8598                 if (!(get_alloc_profile(root, space_info->flags) &
8599                       (BTRFS_BLOCK_GROUP_RAID10 |
8600                        BTRFS_BLOCK_GROUP_RAID1 |
8601                        BTRFS_BLOCK_GROUP_RAID5 |
8602                        BTRFS_BLOCK_GROUP_RAID6 |
8603                        BTRFS_BLOCK_GROUP_DUP)))
8604                         continue;
8605                 /*
8606                  * avoid allocating from un-mirrored block group if there are
8607                  * mirrored block groups.
8608                  */
8609                 list_for_each_entry(cache,
8610                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8611                                 list)
8612                         set_block_group_ro(cache, 1);
8613                 list_for_each_entry(cache,
8614                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8615                                 list)
8616                         set_block_group_ro(cache, 1);
8617         }
8618
8619         init_global_block_rsv(info);
8620         ret = 0;
8621 error:
8622         btrfs_free_path(path);
8623         return ret;
8624 }
8625
8626 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8627                                        struct btrfs_root *root)
8628 {
8629         struct btrfs_block_group_cache *block_group, *tmp;
8630         struct btrfs_root *extent_root = root->fs_info->extent_root;
8631         struct btrfs_block_group_item item;
8632         struct btrfs_key key;
8633         int ret = 0;
8634
8635         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8636                                  new_bg_list) {
8637                 list_del_init(&block_group->new_bg_list);
8638
8639                 if (ret)
8640                         continue;
8641
8642                 spin_lock(&block_group->lock);
8643                 memcpy(&item, &block_group->item, sizeof(item));
8644                 memcpy(&key, &block_group->key, sizeof(key));
8645                 spin_unlock(&block_group->lock);
8646
8647                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8648                                         sizeof(item));
8649                 if (ret)
8650                         btrfs_abort_transaction(trans, extent_root, ret);
8651                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8652                                                key.objectid, key.offset);
8653                 if (ret)
8654                         btrfs_abort_transaction(trans, extent_root, ret);
8655         }
8656 }
8657
8658 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8659                            struct btrfs_root *root, u64 bytes_used,
8660                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8661                            u64 size)
8662 {
8663         int ret;
8664         struct btrfs_root *extent_root;
8665         struct btrfs_block_group_cache *cache;
8666
8667         extent_root = root->fs_info->extent_root;
8668
8669         root->fs_info->last_trans_log_full_commit = trans->transid;
8670
8671         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8672         if (!cache)
8673                 return -ENOMEM;
8674         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8675                                         GFP_NOFS);
8676         if (!cache->free_space_ctl) {
8677                 kfree(cache);
8678                 return -ENOMEM;
8679         }
8680
8681         cache->key.objectid = chunk_offset;
8682         cache->key.offset = size;
8683         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8684         cache->sectorsize = root->sectorsize;
8685         cache->fs_info = root->fs_info;
8686         cache->full_stripe_len = btrfs_full_stripe_len(root,
8687                                                &root->fs_info->mapping_tree,
8688                                                chunk_offset);
8689
8690         atomic_set(&cache->count, 1);
8691         spin_lock_init(&cache->lock);
8692         INIT_LIST_HEAD(&cache->list);
8693         INIT_LIST_HEAD(&cache->cluster_list);
8694         INIT_LIST_HEAD(&cache->new_bg_list);
8695
8696         btrfs_init_free_space_ctl(cache);
8697
8698         btrfs_set_block_group_used(&cache->item, bytes_used);
8699         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8700         cache->flags = type;
8701         btrfs_set_block_group_flags(&cache->item, type);
8702
8703         cache->last_byte_to_unpin = (u64)-1;
8704         cache->cached = BTRFS_CACHE_FINISHED;
8705         ret = exclude_super_stripes(root, cache);
8706         if (ret) {
8707                 /*
8708                  * We may have excluded something, so call this just in
8709                  * case.
8710                  */
8711                 free_excluded_extents(root, cache);
8712                 kfree(cache->free_space_ctl);
8713                 kfree(cache);
8714                 return ret;
8715         }
8716
8717         add_new_free_space(cache, root->fs_info, chunk_offset,
8718                            chunk_offset + size);
8719
8720         free_excluded_extents(root, cache);
8721
8722         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8723         if (ret) {
8724                 btrfs_remove_free_space_cache(cache);
8725                 btrfs_put_block_group(cache);
8726                 return ret;
8727         }
8728
8729         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8730                                 &cache->space_info);
8731         if (ret) {
8732                 btrfs_remove_free_space_cache(cache);
8733                 spin_lock(&root->fs_info->block_group_cache_lock);
8734                 rb_erase(&cache->cache_node,
8735                          &root->fs_info->block_group_cache_tree);
8736                 spin_unlock(&root->fs_info->block_group_cache_lock);
8737                 btrfs_put_block_group(cache);
8738                 return ret;
8739         }
8740         update_global_block_rsv(root->fs_info);
8741
8742         spin_lock(&cache->space_info->lock);
8743         cache->space_info->bytes_readonly += cache->bytes_super;
8744         spin_unlock(&cache->space_info->lock);
8745
8746         __link_block_group(cache->space_info, cache);
8747
8748         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8749
8750         set_avail_alloc_bits(extent_root->fs_info, type);
8751
8752         return 0;
8753 }
8754
8755 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8756 {
8757         u64 extra_flags = chunk_to_extended(flags) &
8758                                 BTRFS_EXTENDED_PROFILE_MASK;
8759
8760         write_seqlock(&fs_info->profiles_lock);
8761         if (flags & BTRFS_BLOCK_GROUP_DATA)
8762                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8763         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8764                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8765         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8766                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8767         write_sequnlock(&fs_info->profiles_lock);
8768 }
8769
8770 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8771                              struct btrfs_root *root, u64 group_start)
8772 {
8773         struct btrfs_path *path;
8774         struct btrfs_block_group_cache *block_group;
8775         struct btrfs_free_cluster *cluster;
8776         struct btrfs_root *tree_root = root->fs_info->tree_root;
8777         struct btrfs_key key;
8778         struct inode *inode;
8779         int ret;
8780         int index;
8781         int factor;
8782
8783         root = root->fs_info->extent_root;
8784
8785         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8786         BUG_ON(!block_group);
8787         BUG_ON(!block_group->ro);
8788
8789         /*
8790          * Free the reserved super bytes from this block group before
8791          * remove it.
8792          */
8793         free_excluded_extents(root, block_group);
8794
8795         memcpy(&key, &block_group->key, sizeof(key));
8796         index = get_block_group_index(block_group);
8797         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8798                                   BTRFS_BLOCK_GROUP_RAID1 |
8799                                   BTRFS_BLOCK_GROUP_RAID10))
8800                 factor = 2;
8801         else
8802                 factor = 1;
8803
8804         /* make sure this block group isn't part of an allocation cluster */
8805         cluster = &root->fs_info->data_alloc_cluster;
8806         spin_lock(&cluster->refill_lock);
8807         btrfs_return_cluster_to_free_space(block_group, cluster);
8808         spin_unlock(&cluster->refill_lock);
8809
8810         /*
8811          * make sure this block group isn't part of a metadata
8812          * allocation cluster
8813          */
8814         cluster = &root->fs_info->meta_alloc_cluster;
8815         spin_lock(&cluster->refill_lock);
8816         btrfs_return_cluster_to_free_space(block_group, cluster);
8817         spin_unlock(&cluster->refill_lock);
8818
8819         path = btrfs_alloc_path();
8820         if (!path) {
8821                 ret = -ENOMEM;
8822                 goto out;
8823         }
8824
8825         inode = lookup_free_space_inode(tree_root, block_group, path);
8826         if (!IS_ERR(inode)) {
8827                 ret = btrfs_orphan_add(trans, inode);
8828                 if (ret) {
8829                         btrfs_add_delayed_iput(inode);
8830                         goto out;
8831                 }
8832                 clear_nlink(inode);
8833                 /* One for the block groups ref */
8834                 spin_lock(&block_group->lock);
8835                 if (block_group->iref) {
8836                         block_group->iref = 0;
8837                         block_group->inode = NULL;
8838                         spin_unlock(&block_group->lock);
8839                         iput(inode);
8840                 } else {
8841                         spin_unlock(&block_group->lock);
8842                 }
8843                 /* One for our lookup ref */
8844                 btrfs_add_delayed_iput(inode);
8845         }
8846
8847         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8848         key.offset = block_group->key.objectid;
8849         key.type = 0;
8850
8851         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8852         if (ret < 0)
8853                 goto out;
8854         if (ret > 0)
8855                 btrfs_release_path(path);
8856         if (ret == 0) {
8857                 ret = btrfs_del_item(trans, tree_root, path);
8858                 if (ret)
8859                         goto out;
8860                 btrfs_release_path(path);
8861         }
8862
8863         spin_lock(&root->fs_info->block_group_cache_lock);
8864         rb_erase(&block_group->cache_node,
8865                  &root->fs_info->block_group_cache_tree);
8866
8867         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8868                 root->fs_info->first_logical_byte = (u64)-1;
8869         spin_unlock(&root->fs_info->block_group_cache_lock);
8870
8871         down_write(&block_group->space_info->groups_sem);
8872         /*
8873          * we must use list_del_init so people can check to see if they
8874          * are still on the list after taking the semaphore
8875          */
8876         list_del_init(&block_group->list);
8877         if (list_empty(&block_group->space_info->block_groups[index])) {
8878                 kobject_del(&block_group->space_info->block_group_kobjs[index]);
8879                 kobject_put(&block_group->space_info->block_group_kobjs[index]);
8880                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8881         }
8882         up_write(&block_group->space_info->groups_sem);
8883
8884         if (block_group->cached == BTRFS_CACHE_STARTED)
8885                 wait_block_group_cache_done(block_group);
8886
8887         btrfs_remove_free_space_cache(block_group);
8888
8889         spin_lock(&block_group->space_info->lock);
8890         block_group->space_info->total_bytes -= block_group->key.offset;
8891         block_group->space_info->bytes_readonly -= block_group->key.offset;
8892         block_group->space_info->disk_total -= block_group->key.offset * factor;
8893         spin_unlock(&block_group->space_info->lock);
8894
8895         memcpy(&key, &block_group->key, sizeof(key));
8896
8897         btrfs_clear_space_info_full(root->fs_info);
8898
8899         btrfs_put_block_group(block_group);
8900         btrfs_put_block_group(block_group);
8901
8902         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8903         if (ret > 0)
8904                 ret = -EIO;
8905         if (ret < 0)
8906                 goto out;
8907
8908         ret = btrfs_del_item(trans, root, path);
8909 out:
8910         btrfs_free_path(path);
8911         return ret;
8912 }
8913
8914 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8915 {
8916         struct btrfs_space_info *space_info;
8917         struct btrfs_super_block *disk_super;
8918         u64 features;
8919         u64 flags;
8920         int mixed = 0;
8921         int ret;
8922
8923         disk_super = fs_info->super_copy;
8924         if (!btrfs_super_root(disk_super))
8925                 return 1;
8926
8927         features = btrfs_super_incompat_flags(disk_super);
8928         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8929                 mixed = 1;
8930
8931         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8932         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8933         if (ret)
8934                 goto out;
8935
8936         if (mixed) {
8937                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8938                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8939         } else {
8940                 flags = BTRFS_BLOCK_GROUP_METADATA;
8941                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8942                 if (ret)
8943                         goto out;
8944
8945                 flags = BTRFS_BLOCK_GROUP_DATA;
8946                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8947         }
8948 out:
8949         return ret;
8950 }
8951
8952 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8953 {
8954         return unpin_extent_range(root, start, end);
8955 }
8956
8957 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8958                                u64 num_bytes, u64 *actual_bytes)
8959 {
8960         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8961 }
8962
8963 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8964 {
8965         struct btrfs_fs_info *fs_info = root->fs_info;
8966         struct btrfs_block_group_cache *cache = NULL;
8967         u64 group_trimmed;
8968         u64 start;
8969         u64 end;
8970         u64 trimmed = 0;
8971         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8972         int ret = 0;
8973
8974         /*
8975          * try to trim all FS space, our block group may start from non-zero.
8976          */
8977         if (range->len == total_bytes)
8978                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8979         else
8980                 cache = btrfs_lookup_block_group(fs_info, range->start);
8981
8982         while (cache) {
8983                 if (cache->key.objectid >= (range->start + range->len)) {
8984                         btrfs_put_block_group(cache);
8985                         break;
8986                 }
8987
8988                 start = max(range->start, cache->key.objectid);
8989                 end = min(range->start + range->len,
8990                                 cache->key.objectid + cache->key.offset);
8991
8992                 if (end - start >= range->minlen) {
8993                         if (!block_group_cache_done(cache)) {
8994                                 ret = cache_block_group(cache, 0);
8995                                 if (ret) {
8996                                         btrfs_put_block_group(cache);
8997                                         break;
8998                                 }
8999                                 ret = wait_block_group_cache_done(cache);
9000                                 if (ret) {
9001                                         btrfs_put_block_group(cache);
9002                                         break;
9003                                 }
9004                         }
9005                         ret = btrfs_trim_block_group(cache,
9006                                                      &group_trimmed,
9007                                                      start,
9008                                                      end,
9009                                                      range->minlen);
9010
9011                         trimmed += group_trimmed;
9012                         if (ret) {
9013                                 btrfs_put_block_group(cache);
9014                                 break;
9015                         }
9016                 }
9017
9018                 cache = next_block_group(fs_info->tree_root, cache);
9019         }
9020
9021         range->len = trimmed;
9022         return ret;
9023 }