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 "compat.h"
  29 #include "hash.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "transaction.h"
  34 #include "volumes.h"
  35 #include "raid56.h"
  36 #include "locking.h"
  37 #include "free-space-cache.h"
  38 #include "math.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                                 caching_ctl->progress = last;
 447                                 btrfs_release_path(path);
 448                                 up_read(&fs_info->extent_commit_sem);
 449                                 mutex_unlock(&caching_ctl->mutex);
 450                                 cond_resched();
 451                                 goto again;
 452                         }
 453
 454                         ret = btrfs_next_leaf(extent_root, path);
 455                         if (ret < 0)
 456                                 goto err;
 457                         if (ret)
 458                                 break;
 459                         leaf = path->nodes[0];
 460                         nritems = btrfs_header_nritems(leaf);
 461                         continue;
 462                 }
 463
 464                 if (key.objectid < last) {
 465                         key.objectid = last;
 466                         key.offset = 0;
 467                         key.type = BTRFS_EXTENT_ITEM_KEY;
 468
 469                         caching_ctl->progress = last;
 470                         btrfs_release_path(path);
 471                         goto next;
 472                 }
 473
 474                 if (key.objectid < block_group->key.objectid) {
 475                         path->slots[0]++;
 476                         continue;
 477                 }
 478
 479                 if (key.objectid >= block_group->key.objectid +
 480                     block_group->key.offset)
 481                         break;
 482
 483                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 484                     key.type == BTRFS_METADATA_ITEM_KEY) {
 485                         total_found += add_new_free_space(block_group,
 486                                                           fs_info, last,
 487                                                           key.objectid);
 488                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 489                                 last = key.objectid +
 490                                         fs_info->tree_root->leafsize;
 491                         else
 492                                 last = key.objectid + key.offset;
 493
 494                         if (total_found > (1024 * 1024 * 2)) {
 495                                 total_found = 0;
 496                                 wake_up(&caching_ctl->wait);
 497                         }
 498                 }
 499                 path->slots[0]++;
 500         }
 501         ret = 0;
 502
 503         total_found += add_new_free_space(block_group, fs_info, last,
 504                                           block_group->key.objectid +
 505                                           block_group->key.offset);
 506         caching_ctl->progress = (u64)-1;
 507
 508         spin_lock(&block_group->lock);
 509         block_group->caching_ctl = NULL;
 510         block_group->cached = BTRFS_CACHE_FINISHED;
 511         spin_unlock(&block_group->lock);
 512
 513 err:
 514         btrfs_free_path(path);
 515         up_read(&fs_info->extent_commit_sem);
 516
 517         free_excluded_extents(extent_root, block_group);
 518
 519         mutex_unlock(&caching_ctl->mutex);
 520 out:
 521         if (ret) {
 522                 spin_lock(&block_group->lock);
 523                 block_group->caching_ctl = NULL;
 524                 block_group->cached = BTRFS_CACHE_ERROR;
 525                 spin_unlock(&block_group->lock);
 526         }
 527         wake_up(&caching_ctl->wait);
 528
 529         put_caching_control(caching_ctl);
 530         btrfs_put_block_group(block_group);
 531 }
 532
 533 static int cache_block_group(struct btrfs_block_group_cache *cache,
 534                              int load_cache_only)
 535 {
 536         DEFINE_WAIT(wait);
 537         struct btrfs_fs_info *fs_info = cache->fs_info;
 538         struct btrfs_caching_control *caching_ctl;
 539         int ret = 0;
 540
 541         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 542         if (!caching_ctl)
 543                 return -ENOMEM;
 544
 545         INIT_LIST_HEAD(&caching_ctl->list);
 546         mutex_init(&caching_ctl->mutex);
 547         init_waitqueue_head(&caching_ctl->wait);
 548         caching_ctl->block_group = cache;
 549         caching_ctl->progress = cache->key.objectid;
 550         atomic_set(&caching_ctl->count, 1);
 551         caching_ctl->work.func = caching_thread;
 552
 553         spin_lock(&cache->lock);
 554         /*
 555          * This should be a rare occasion, but this could happen I think in the
 556          * case where one thread starts to load the space cache info, and then
 557          * some other thread starts a transaction commit which tries to do an
 558          * allocation while the other thread is still loading the space cache
 559          * info.  The previous loop should have kept us from choosing this block
 560          * group, but if we've moved to the state where we will wait on caching
 561          * block groups we need to first check if we're doing a fast load here,
 562          * so we can wait for it to finish, otherwise we could end up allocating
 563          * from a block group who's cache gets evicted for one reason or
 564          * another.
 565          */
 566         while (cache->cached == BTRFS_CACHE_FAST) {
 567                 struct btrfs_caching_control *ctl;
 568
 569                 ctl = cache->caching_ctl;
 570                 atomic_inc(&ctl->count);
 571                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 572                 spin_unlock(&cache->lock);
 573
 574                 schedule();
 575
 576                 finish_wait(&ctl->wait, &wait);
 577                 put_caching_control(ctl);
 578                 spin_lock(&cache->lock);
 579         }
 580
 581         if (cache->cached != BTRFS_CACHE_NO) {
 582                 spin_unlock(&cache->lock);
 583                 kfree(caching_ctl);
 584                 return 0;
 585         }
 586         WARN_ON(cache->caching_ctl);
 587         cache->caching_ctl = caching_ctl;
 588         cache->cached = BTRFS_CACHE_FAST;
 589         spin_unlock(&cache->lock);
 590
 591         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                 } else {
 600                         if (load_cache_only) {
 601                                 cache->caching_ctl = NULL;
 602                                 cache->cached = BTRFS_CACHE_NO;
 603                         } else {
 604                                 cache->cached = BTRFS_CACHE_STARTED;
 605                         }
 606                 }
 607                 spin_unlock(&cache->lock);
 608                 wake_up(&caching_ctl->wait);
 609                 if (ret == 1) {
 610                         put_caching_control(caching_ctl);
 611                         free_excluded_extents(fs_info->extent_root, cache);
 612                         return 0;
 613                 }
 614         } else {
 615                 /*
 616                  * We are not going to do the fast caching, set cached to the
 617                  * appropriate value and wakeup any waiters.
 618                  */
 619                 spin_lock(&cache->lock);
 620                 if (load_cache_only) {
 621                         cache->caching_ctl = NULL;
 622                         cache->cached = BTRFS_CACHE_NO;
 623                 } else {
 624                         cache->cached = BTRFS_CACHE_STARTED;
 625                 }
 626                 spin_unlock(&cache->lock);
 627                 wake_up(&caching_ctl->wait);
 628         }
 629
 630         if (load_cache_only) {
 631                 put_caching_control(caching_ctl);
 632                 return 0;
 633         }
 634
 635         down_write(&fs_info->extent_commit_sem);
 636         atomic_inc(&caching_ctl->count);
 637         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 638         up_write(&fs_info->extent_commit_sem);
 639
 640         btrfs_get_block_group(cache);
 641
 642         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 643
 644         return ret;
 645 }
 646
 647 /*
 648  * return the block group that starts at or after bytenr
 649  */
 650 static struct btrfs_block_group_cache *
 651 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 652 {
 653         struct btrfs_block_group_cache *cache;
 654
 655         cache = block_group_cache_tree_search(info, bytenr, 0);
 656
 657         return cache;
 658 }
 659
 660 /*
 661  * return the block group that contains the given bytenr
 662  */
 663 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 664                                                  struct btrfs_fs_info *info,
 665                                                  u64 bytenr)
 666 {
 667         struct btrfs_block_group_cache *cache;
 668
 669         cache = block_group_cache_tree_search(info, bytenr, 1);
 670
 671         return cache;
 672 }
 673
 674 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 675                                                   u64 flags)
 676 {
 677         struct list_head *head = &info->space_info;
 678         struct btrfs_space_info *found;
 679
 680         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 681
 682         rcu_read_lock();
 683         list_for_each_entry_rcu(found, head, list) {
 684                 if (found->flags & flags) {
 685                         rcu_read_unlock();
 686                         return found;
 687                 }
 688         }
 689         rcu_read_unlock();
 690         return NULL;
 691 }
 692
 693 /*
 694  * after adding space to the filesystem, we need to clear the full flags
 695  * on all the space infos.
 696  */
 697 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 698 {
 699         struct list_head *head = &info->space_info;
 700         struct btrfs_space_info *found;
 701
 702         rcu_read_lock();
 703         list_for_each_entry_rcu(found, head, list)
 704                 found->full = 0;
 705         rcu_read_unlock();
 706 }
 707
 708 /* simple helper to search for an existing extent at a given offset */
 709 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 710 {
 711         int ret;
 712         struct btrfs_key key;
 713         struct btrfs_path *path;
 714
 715         path = btrfs_alloc_path();
 716         if (!path)
 717                 return -ENOMEM;
 718
 719         key.objectid = start;
 720         key.offset = len;
 721         key.type = BTRFS_EXTENT_ITEM_KEY;
 722         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 723                                 0, 0);
 724         if (ret > 0) {
 725                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 726                 if (key.objectid == start &&
 727                     key.type == BTRFS_METADATA_ITEM_KEY)
 728                         ret = 0;
 729         }
 730         btrfs_free_path(path);
 731         return ret;
 732 }
 733
 734 /*
 735  * helper function to lookup reference count and flags of a tree block.
 736  *
 737  * the head node for delayed ref is used to store the sum of all the
 738  * reference count modifications queued up in the rbtree. the head
 739  * node may also store the extent flags to set. This way you can check
 740  * to see what the reference count and extent flags would be if all of
 741  * the delayed refs are not processed.
 742  */
 743 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 744                              struct btrfs_root *root, u64 bytenr,
 745                              u64 offset, int metadata, u64 *refs, u64 *flags)
 746 {
 747         struct btrfs_delayed_ref_head *head;
 748         struct btrfs_delayed_ref_root *delayed_refs;
 749         struct btrfs_path *path;
 750         struct btrfs_extent_item *ei;
 751         struct extent_buffer *leaf;
 752         struct btrfs_key key;
 753         u32 item_size;
 754         u64 num_refs;
 755         u64 extent_flags;
 756         int ret;
 757
 758         /*
 759          * If we don't have skinny metadata, don't bother doing anything
 760          * different
 761          */
 762         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 763                 offset = root->leafsize;
 764                 metadata = 0;
 765         }
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         if (metadata) {
 772                 key.objectid = bytenr;
 773                 key.type = BTRFS_METADATA_ITEM_KEY;
 774                 key.offset = offset;
 775         } else {
 776                 key.objectid = bytenr;
 777                 key.type = BTRFS_EXTENT_ITEM_KEY;
 778                 key.offset = offset;
 779         }
 780
 781         if (!trans) {
 782                 path->skip_locking = 1;
 783                 path->search_commit_root = 1;
 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                 metadata = 0;
 793                 if (path->slots[0]) {
 794                         path->slots[0]--;
 795                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 796                                               path->slots[0]);
 797                         if (key.objectid == bytenr &&
 798                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 799                             key.offset == root->leafsize)
 800                                 ret = 0;
 801                 }
 802                 if (ret) {
 803                         key.objectid = bytenr;
 804                         key.type = BTRFS_EXTENT_ITEM_KEY;
 805                         key.offset = root->leafsize;
 806                         btrfs_release_path(path);
 807                         goto again;
 808                 }
 809         }
 810
 811         if (ret == 0) {
 812                 leaf = path->nodes[0];
 813                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 814                 if (item_size >= sizeof(*ei)) {
 815                         ei = btrfs_item_ptr(leaf, path->slots[0],
 816                                             struct btrfs_extent_item);
 817                         num_refs = btrfs_extent_refs(leaf, ei);
 818                         extent_flags = btrfs_extent_flags(leaf, ei);
 819                 } else {
 820 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 821                         struct btrfs_extent_item_v0 *ei0;
 822                         BUG_ON(item_size != sizeof(*ei0));
 823                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 824                                              struct btrfs_extent_item_v0);
 825                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 826                         /* FIXME: this isn't correct for data */
 827                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 828 #else
 829                         BUG();
 830 #endif
 831                 }
 832                 BUG_ON(num_refs == 0);
 833         } else {
 834                 num_refs = 0;
 835                 extent_flags = 0;
 836                 ret = 0;
 837         }
 838
 839         if (!trans)
 840                 goto out;
 841
 842         delayed_refs = &trans->transaction->delayed_refs;
 843         spin_lock(&delayed_refs->lock);
 844         head = btrfs_find_delayed_ref_head(trans, bytenr);
 845         if (head) {
 846                 if (!mutex_trylock(&head->mutex)) {
 847                         atomic_inc(&head->node.refs);
 848                         spin_unlock(&delayed_refs->lock);
 849
 850                         btrfs_release_path(path);
 851
 852                         /*
 853                          * Mutex was contended, block until it's released and try
 854                          * again
 855                          */
 856                         mutex_lock(&head->mutex);
 857                         mutex_unlock(&head->mutex);
 858                         btrfs_put_delayed_ref(&head->node);
 859                         goto again;
 860                 }
 861                 if (head->extent_op && head->extent_op->update_flags)
 862                         extent_flags |= head->extent_op->flags_to_set;
 863                 else
 864                         BUG_ON(num_refs == 0);
 865
 866                 num_refs += head->node.ref_mod;
 867                 mutex_unlock(&head->mutex);
 868         }
 869         spin_unlock(&delayed_refs->lock);
 870 out:
 871         WARN_ON(num_refs == 0);
 872         if (refs)
 873                 *refs = num_refs;
 874         if (flags)
 875                 *flags = extent_flags;
 876 out_free:
 877         btrfs_free_path(path);
 878         return ret;
 879 }
 880
 881 /*
 882  * Back reference rules.  Back refs have three main goals:
 883  *
 884  * 1) differentiate between all holders of references to an extent so that
 885  *    when a reference is dropped we can make sure it was a valid reference
 886  *    before freeing the extent.
 887  *
 888  * 2) Provide enough information to quickly find the holders of an extent
 889  *    if we notice a given block is corrupted or bad.
 890  *
 891  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 892  *    maintenance.  This is actually the same as #2, but with a slightly
 893  *    different use case.
 894  *
 895  * There are two kinds of back refs. The implicit back refs is optimized
 896  * for pointers in non-shared tree blocks. For a given pointer in a block,
 897  * back refs of this kind provide information about the block's owner tree
 898  * and the pointer's key. These information allow us to find the block by
 899  * b-tree searching. The full back refs is for pointers in tree blocks not
 900  * referenced by their owner trees. The location of tree block is recorded
 901  * in the back refs. Actually the full back refs is generic, and can be
 902  * used in all cases the implicit back refs is used. The major shortcoming
 903  * of the full back refs is its overhead. Every time a tree block gets
 904  * COWed, we have to update back refs entry for all pointers in it.
 905  *
 906  * For a newly allocated tree block, we use implicit back refs for
 907  * pointers in it. This means most tree related operations only involve
 908  * implicit back refs. For a tree block created in old transaction, the
 909  * only way to drop a reference to it is COW it. So we can detect the
 910  * event that tree block loses its owner tree's reference and do the
 911  * back refs conversion.
 912  *
 913  * When a tree block is COW'd through a tree, there are four cases:
 914  *
 915  * The reference count of the block is one and the tree is the block's
 916  * owner tree. Nothing to do in this case.
 917  *
 918  * The reference count of the block is one and the tree is not the
 919  * block's owner tree. In this case, full back refs is used for pointers
 920  * in the block. Remove these full back refs, add implicit back refs for
 921  * every pointers in the new block.
 922  *
 923  * The reference count of the block is greater than one and the tree is
 924  * the block's owner tree. In this case, implicit back refs is used for
 925  * pointers in the block. Add full back refs for every pointers in the
 926  * block, increase lower level extents' reference counts. The original
 927  * implicit back refs are entailed to the new block.
 928  *
 929  * The reference count of the block is greater than one and the tree is
 930  * not the block's owner tree. Add implicit back refs for every pointer in
 931  * the new block, increase lower level extents' reference count.
 932  *
 933  * Back Reference Key composing:
 934  *
 935  * The key objectid corresponds to the first byte in the extent,
 936  * The key type is used to differentiate between types of back refs.
 937  * There are different meanings of the key offset for different types
 938  * of back refs.
 939  *
 940  * File extents can be referenced by:
 941  *
 942  * - multiple snapshots, subvolumes, or different generations in one subvol
 943  * - different files inside a single subvolume
 944  * - different offsets inside a file (bookend extents in file.c)
 945  *
 946  * The extent ref structure for the implicit back refs has fields for:
 947  *
 948  * - Objectid of the subvolume root
 949  * - objectid of the file holding the reference
 950  * - original offset in the file
 951  * - how many bookend extents
 952  *
 953  * The key offset for the implicit back refs is hash of the first
 954  * three fields.
 955  *
 956  * The extent ref structure for the full back refs has field for:
 957  *
 958  * - number of pointers in the tree leaf
 959  *
 960  * The key offset for the implicit back refs is the first byte of
 961  * the tree leaf
 962  *
 963  * When a file extent is allocated, The implicit back refs is used.
 964  * the fields are filled in:
 965  *
 966  *     (root_key.objectid, inode objectid, offset in file, 1)
 967  *
 968  * When a file extent is removed file truncation, we find the
 969  * corresponding implicit back refs and check the following fields:
 970  *
 971  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 972  *
 973  * Btree extents can be referenced by:
 974  *
 975  * - Different subvolumes
 976  *
 977  * Both the implicit back refs and the full back refs for tree blocks
 978  * only consist of key. The key offset for the implicit back refs is
 979  * objectid of block's owner tree. The key offset for the full back refs
 980  * is the first byte of parent block.
 981  *
 982  * When implicit back refs is used, information about the lowest key and
 983  * level of the tree block are required. These information are stored in
 984  * tree block info structure.
 985  */
 986
 987 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 988 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 989                                   struct btrfs_root *root,
 990                                   struct btrfs_path *path,
 991                                   u64 owner, u32 extra_size)
 992 {
 993         struct btrfs_extent_item *item;
 994         struct btrfs_extent_item_v0 *ei0;
 995         struct btrfs_extent_ref_v0 *ref0;
 996         struct btrfs_tree_block_info *bi;
 997         struct extent_buffer *leaf;
 998         struct btrfs_key key;
 999         struct btrfs_key found_key;
1000         u32 new_size = sizeof(*item);
1001         u64 refs;
1002         int ret;
1003
1004         leaf = path->nodes[0];
1005         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1006
1007         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1008         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1009                              struct btrfs_extent_item_v0);
1010         refs = btrfs_extent_refs_v0(leaf, ei0);
1011
1012         if (owner == (u64)-1) {
1013                 while (1) {
1014                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1015                                 ret = btrfs_next_leaf(root, path);
1016                                 if (ret < 0)
1017                                         return ret;
1018                                 BUG_ON(ret > 0); /* Corruption */
1019                                 leaf = path->nodes[0];
1020                         }
1021                         btrfs_item_key_to_cpu(leaf, &found_key,
1022                                               path->slots[0]);
1023                         BUG_ON(key.objectid != found_key.objectid);
1024                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1025                                 path->slots[0]++;
1026                                 continue;
1027                         }
1028                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1029                                               struct btrfs_extent_ref_v0);
1030                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1031                         break;
1032                 }
1033         }
1034         btrfs_release_path(path);
1035
1036         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1037                 new_size += sizeof(*bi);
1038
1039         new_size -= sizeof(*ei0);
1040         ret = btrfs_search_slot(trans, root, &key, path,
1041                                 new_size + extra_size, 1);
1042         if (ret < 0)
1043                 return ret;
1044         BUG_ON(ret); /* Corruption */
1045
1046         btrfs_extend_item(root, path, new_size);
1047
1048         leaf = path->nodes[0];
1049         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1050         btrfs_set_extent_refs(leaf, item, refs);
1051         /* FIXME: get real generation */
1052         btrfs_set_extent_generation(leaf, item, 0);
1053         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1054                 btrfs_set_extent_flags(leaf, item,
1055                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1056                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1057                 bi = (struct btrfs_tree_block_info *)(item + 1);
1058                 /* FIXME: get first key of the block */
1059                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1060                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1061         } else {
1062                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1063         }
1064         btrfs_mark_buffer_dirty(leaf);
1065         return 0;
1066 }
1067 #endif
1068
1069 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1070 {
1071         u32 high_crc = ~(u32)0;
1072         u32 low_crc = ~(u32)0;
1073         __le64 lenum;
1074
1075         lenum = cpu_to_le64(root_objectid);
1076         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1077         lenum = cpu_to_le64(owner);
1078         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1079         lenum = cpu_to_le64(offset);
1080         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1081
1082         return ((u64)high_crc << 31) ^ (u64)low_crc;
1083 }
1084
1085 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1086                                      struct btrfs_extent_data_ref *ref)
1087 {
1088         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1089                                     btrfs_extent_data_ref_objectid(leaf, ref),
1090                                     btrfs_extent_data_ref_offset(leaf, ref));
1091 }
1092
1093 static int match_extent_data_ref(struct extent_buffer *leaf,
1094                                  struct btrfs_extent_data_ref *ref,
1095                                  u64 root_objectid, u64 owner, u64 offset)
1096 {
1097         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1098             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1099             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1100                 return 0;
1101         return 1;
1102 }
1103
1104 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1105                                            struct btrfs_root *root,
1106                                            struct btrfs_path *path,
1107                                            u64 bytenr, u64 parent,
1108                                            u64 root_objectid,
1109                                            u64 owner, u64 offset)
1110 {
1111         struct btrfs_key key;
1112         struct btrfs_extent_data_ref *ref;
1113         struct extent_buffer *leaf;
1114         u32 nritems;
1115         int ret;
1116         int recow;
1117         int err = -ENOENT;
1118
1119         key.objectid = bytenr;
1120         if (parent) {
1121                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1122                 key.offset = parent;
1123         } else {
1124                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1125                 key.offset = hash_extent_data_ref(root_objectid,
1126                                                   owner, offset);
1127         }
1128 again:
1129         recow = 0;
1130         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1131         if (ret < 0) {
1132                 err = ret;
1133                 goto fail;
1134         }
1135
1136         if (parent) {
1137                 if (!ret)
1138                         return 0;
1139 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1140                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1141                 btrfs_release_path(path);
1142                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1143                 if (ret < 0) {
1144                         err = ret;
1145                         goto fail;
1146                 }
1147                 if (!ret)
1148                         return 0;
1149 #endif
1150                 goto fail;
1151         }
1152
1153         leaf = path->nodes[0];
1154         nritems = btrfs_header_nritems(leaf);
1155         while (1) {
1156                 if (path->slots[0] >= nritems) {
1157                         ret = btrfs_next_leaf(root, path);
1158                         if (ret < 0)
1159                                 err = ret;
1160                         if (ret)
1161                                 goto fail;
1162
1163                         leaf = path->nodes[0];
1164                         nritems = btrfs_header_nritems(leaf);
1165                         recow = 1;
1166                 }
1167
1168                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1169                 if (key.objectid != bytenr ||
1170                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1171                         goto fail;
1172
1173                 ref = btrfs_item_ptr(leaf, path->slots[0],
1174                                      struct btrfs_extent_data_ref);
1175
1176                 if (match_extent_data_ref(leaf, ref, root_objectid,
1177                                           owner, offset)) {
1178                         if (recow) {
1179                                 btrfs_release_path(path);
1180                                 goto again;
1181                         }
1182                         err = 0;
1183                         break;
1184                 }
1185                 path->slots[0]++;
1186         }
1187 fail:
1188         return err;
1189 }
1190
1191 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1192                                            struct btrfs_root *root,
1193                                            struct btrfs_path *path,
1194                                            u64 bytenr, u64 parent,
1195                                            u64 root_objectid, u64 owner,
1196                                            u64 offset, int refs_to_add)
1197 {
1198         struct btrfs_key key;
1199         struct extent_buffer *leaf;
1200         u32 size;
1201         u32 num_refs;
1202         int ret;
1203
1204         key.objectid = bytenr;
1205         if (parent) {
1206                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1207                 key.offset = parent;
1208                 size = sizeof(struct btrfs_shared_data_ref);
1209         } else {
1210                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1211                 key.offset = hash_extent_data_ref(root_objectid,
1212                                                   owner, offset);
1213                 size = sizeof(struct btrfs_extent_data_ref);
1214         }
1215
1216         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1217         if (ret && ret != -EEXIST)
1218                 goto fail;
1219
1220         leaf = path->nodes[0];
1221         if (parent) {
1222                 struct btrfs_shared_data_ref *ref;
1223                 ref = btrfs_item_ptr(leaf, path->slots[0],
1224                                      struct btrfs_shared_data_ref);
1225                 if (ret == 0) {
1226                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1227                 } else {
1228                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1229                         num_refs += refs_to_add;
1230                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1231                 }
1232         } else {
1233                 struct btrfs_extent_data_ref *ref;
1234                 while (ret == -EEXIST) {
1235                         ref = btrfs_item_ptr(leaf, path->slots[0],
1236                                              struct btrfs_extent_data_ref);
1237                         if (match_extent_data_ref(leaf, ref, root_objectid,
1238                                                   owner, offset))
1239                                 break;
1240                         btrfs_release_path(path);
1241                         key.offset++;
1242                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1243                                                       size);
1244                         if (ret && ret != -EEXIST)
1245                                 goto fail;
1246
1247                         leaf = path->nodes[0];
1248                 }
1249                 ref = btrfs_item_ptr(leaf, path->slots[0],
1250                                      struct btrfs_extent_data_ref);
1251                 if (ret == 0) {
1252                         btrfs_set_extent_data_ref_root(leaf, ref,
1253                                                        root_objectid);
1254                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1255                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1256                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1257                 } else {
1258                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1259                         num_refs += refs_to_add;
1260                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1261                 }
1262         }
1263         btrfs_mark_buffer_dirty(leaf);
1264         ret = 0;
1265 fail:
1266         btrfs_release_path(path);
1267         return ret;
1268 }
1269
1270 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1271                                            struct btrfs_root *root,
1272                                            struct btrfs_path *path,
1273                                            int refs_to_drop)
1274 {
1275         struct btrfs_key key;
1276         struct btrfs_extent_data_ref *ref1 = NULL;
1277         struct btrfs_shared_data_ref *ref2 = NULL;
1278         struct extent_buffer *leaf;
1279         u32 num_refs = 0;
1280         int ret = 0;
1281
1282         leaf = path->nodes[0];
1283         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1284
1285         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1286                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1287                                       struct btrfs_extent_data_ref);
1288                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1289         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1290                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1291                                       struct btrfs_shared_data_ref);
1292                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1293 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1294         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1295                 struct btrfs_extent_ref_v0 *ref0;
1296                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1297                                       struct btrfs_extent_ref_v0);
1298                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1299 #endif
1300         } else {
1301                 BUG();
1302         }
1303
1304         BUG_ON(num_refs < refs_to_drop);
1305         num_refs -= refs_to_drop;
1306
1307         if (num_refs == 0) {
1308                 ret = btrfs_del_item(trans, root, path);
1309         } else {
1310                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1311                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1312                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1313                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1314 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1315                 else {
1316                         struct btrfs_extent_ref_v0 *ref0;
1317                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1318                                         struct btrfs_extent_ref_v0);
1319                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1320                 }
1321 #endif
1322                 btrfs_mark_buffer_dirty(leaf);
1323         }
1324         return ret;
1325 }
1326
1327 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1328                                           struct btrfs_path *path,
1329                                           struct btrfs_extent_inline_ref *iref)
1330 {
1331         struct btrfs_key key;
1332         struct extent_buffer *leaf;
1333         struct btrfs_extent_data_ref *ref1;
1334         struct btrfs_shared_data_ref *ref2;
1335         u32 num_refs = 0;
1336
1337         leaf = path->nodes[0];
1338         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1339         if (iref) {
1340                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1341                     BTRFS_EXTENT_DATA_REF_KEY) {
1342                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1343                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1344                 } else {
1345                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1346                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1347                 }
1348         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1349                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1350                                       struct btrfs_extent_data_ref);
1351                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1352         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1353                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1354                                       struct btrfs_shared_data_ref);
1355                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1356 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1357         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1358                 struct btrfs_extent_ref_v0 *ref0;
1359                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1360                                       struct btrfs_extent_ref_v0);
1361                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1362 #endif
1363         } else {
1364                 WARN_ON(1);
1365         }
1366         return num_refs;
1367 }
1368
1369 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1370                                           struct btrfs_root *root,
1371                                           struct btrfs_path *path,
1372                                           u64 bytenr, u64 parent,
1373                                           u64 root_objectid)
1374 {
1375         struct btrfs_key key;
1376         int ret;
1377
1378         key.objectid = bytenr;
1379         if (parent) {
1380                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1381                 key.offset = parent;
1382         } else {
1383                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1384                 key.offset = root_objectid;
1385         }
1386
1387         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1388         if (ret > 0)
1389                 ret = -ENOENT;
1390 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1391         if (ret == -ENOENT && parent) {
1392                 btrfs_release_path(path);
1393                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1394                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1395                 if (ret > 0)
1396                         ret = -ENOENT;
1397         }
1398 #endif
1399         return ret;
1400 }
1401
1402 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1403                                           struct btrfs_root *root,
1404                                           struct btrfs_path *path,
1405                                           u64 bytenr, u64 parent,
1406                                           u64 root_objectid)
1407 {
1408         struct btrfs_key key;
1409         int ret;
1410
1411         key.objectid = bytenr;
1412         if (parent) {
1413                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1414                 key.offset = parent;
1415         } else {
1416                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1417                 key.offset = root_objectid;
1418         }
1419
1420         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1421         btrfs_release_path(path);
1422         return ret;
1423 }
1424
1425 static inline int extent_ref_type(u64 parent, u64 owner)
1426 {
1427         int type;
1428         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1429                 if (parent > 0)
1430                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1431                 else
1432                         type = BTRFS_TREE_BLOCK_REF_KEY;
1433         } else {
1434                 if (parent > 0)
1435                         type = BTRFS_SHARED_DATA_REF_KEY;
1436                 else
1437                         type = BTRFS_EXTENT_DATA_REF_KEY;
1438         }
1439         return type;
1440 }
1441
1442 static int find_next_key(struct btrfs_path *path, int level,
1443                          struct btrfs_key *key)
1444
1445 {
1446         for (; level < BTRFS_MAX_LEVEL; level++) {
1447                 if (!path->nodes[level])
1448                         break;
1449                 if (path->slots[level] + 1 >=
1450                     btrfs_header_nritems(path->nodes[level]))
1451                         continue;
1452                 if (level == 0)
1453                         btrfs_item_key_to_cpu(path->nodes[level], key,
1454                                               path->slots[level] + 1);
1455                 else
1456                         btrfs_node_key_to_cpu(path->nodes[level], key,
1457                                               path->slots[level] + 1);
1458                 return 0;
1459         }
1460         return 1;
1461 }
1462
1463 /*
1464  * look for inline back ref. if back ref is found, *ref_ret is set
1465  * to the address of inline back ref, and 0 is returned.
1466  *
1467  * if back ref isn't found, *ref_ret is set to the address where it
1468  * should be inserted, and -ENOENT is returned.
1469  *
1470  * if insert is true and there are too many inline back refs, the path
1471  * points to the extent item, and -EAGAIN is returned.
1472  *
1473  * NOTE: inline back refs are ordered in the same way that back ref
1474  *       items in the tree are ordered.
1475  */
1476 static noinline_for_stack
1477 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1478                                  struct btrfs_root *root,
1479                                  struct btrfs_path *path,
1480                                  struct btrfs_extent_inline_ref **ref_ret,
1481                                  u64 bytenr, u64 num_bytes,
1482                                  u64 parent, u64 root_objectid,
1483                                  u64 owner, u64 offset, int insert)
1484 {
1485         struct btrfs_key key;
1486         struct extent_buffer *leaf;
1487         struct btrfs_extent_item *ei;
1488         struct btrfs_extent_inline_ref *iref;
1489         u64 flags;
1490         u64 item_size;
1491         unsigned long ptr;
1492         unsigned long end;
1493         int extra_size;
1494         int type;
1495         int want;
1496         int ret;
1497         int err = 0;
1498         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1499                                                  SKINNY_METADATA);
1500
1501         key.objectid = bytenr;
1502         key.type = BTRFS_EXTENT_ITEM_KEY;
1503         key.offset = num_bytes;
1504
1505         want = extent_ref_type(parent, owner);
1506         if (insert) {
1507                 extra_size = btrfs_extent_inline_ref_size(want);
1508                 path->keep_locks = 1;
1509         } else
1510                 extra_size = -1;
1511
1512         /*
1513          * Owner is our parent level, so we can just add one to get the level
1514          * for the block we are interested in.
1515          */
1516         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1517                 key.type = BTRFS_METADATA_ITEM_KEY;
1518                 key.offset = owner;
1519         }
1520
1521 again:
1522         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1523         if (ret < 0) {
1524                 err = ret;
1525                 goto out;
1526         }
1527
1528         /*
1529          * We may be a newly converted file system which still has the old fat
1530          * extent entries for metadata, so try and see if we have one of those.
1531          */
1532         if (ret > 0 && skinny_metadata) {
1533                 skinny_metadata = false;
1534                 if (path->slots[0]) {
1535                         path->slots[0]--;
1536                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1537                                               path->slots[0]);
1538                         if (key.objectid == bytenr &&
1539                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1540                             key.offset == num_bytes)
1541                                 ret = 0;
1542                 }
1543                 if (ret) {
1544                         key.type = BTRFS_EXTENT_ITEM_KEY;
1545                         key.offset = num_bytes;
1546                         btrfs_release_path(path);
1547                         goto again;
1548                 }
1549         }
1550
1551         if (ret && !insert) {
1552                 err = -ENOENT;
1553                 goto out;
1554         } else if (ret) {
1555                 err = -EIO;
1556                 WARN_ON(1);
1557                 goto out;
1558         }
1559
1560         leaf = path->nodes[0];
1561         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1562 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1563         if (item_size < sizeof(*ei)) {
1564                 if (!insert) {
1565                         err = -ENOENT;
1566                         goto out;
1567                 }
1568                 ret = convert_extent_item_v0(trans, root, path, owner,
1569                                              extra_size);
1570                 if (ret < 0) {
1571                         err = ret;
1572                         goto out;
1573                 }
1574                 leaf = path->nodes[0];
1575                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1576         }
1577 #endif
1578         BUG_ON(item_size < sizeof(*ei));
1579
1580         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1581         flags = btrfs_extent_flags(leaf, ei);
1582
1583         ptr = (unsigned long)(ei + 1);
1584         end = (unsigned long)ei + item_size;
1585
1586         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1587                 ptr += sizeof(struct btrfs_tree_block_info);
1588                 BUG_ON(ptr > end);
1589         }
1590
1591         err = -ENOENT;
1592         while (1) {
1593                 if (ptr >= end) {
1594                         WARN_ON(ptr > end);
1595                         break;
1596                 }
1597                 iref = (struct btrfs_extent_inline_ref *)ptr;
1598                 type = btrfs_extent_inline_ref_type(leaf, iref);
1599                 if (want < type)
1600                         break;
1601                 if (want > type) {
1602                         ptr += btrfs_extent_inline_ref_size(type);
1603                         continue;
1604                 }
1605
1606                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1607                         struct btrfs_extent_data_ref *dref;
1608                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1609                         if (match_extent_data_ref(leaf, dref, root_objectid,
1610                                                   owner, offset)) {
1611                                 err = 0;
1612                                 break;
1613                         }
1614                         if (hash_extent_data_ref_item(leaf, dref) <
1615                             hash_extent_data_ref(root_objectid, owner, offset))
1616                                 break;
1617                 } else {
1618                         u64 ref_offset;
1619                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1620                         if (parent > 0) {
1621                                 if (parent == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < parent)
1626                                         break;
1627                         } else {
1628                                 if (root_objectid == ref_offset) {
1629                                         err = 0;
1630                                         break;
1631                                 }
1632                                 if (ref_offset < root_objectid)
1633                                         break;
1634                         }
1635                 }
1636                 ptr += btrfs_extent_inline_ref_size(type);
1637         }
1638         if (err == -ENOENT && insert) {
1639                 if (item_size + extra_size >=
1640                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1641                         err = -EAGAIN;
1642                         goto out;
1643                 }
1644                 /*
1645                  * To add new inline back ref, we have to make sure
1646                  * there is no corresponding back ref item.
1647                  * For simplicity, we just do not add new inline back
1648                  * ref if there is any kind of item for this block
1649                  */
1650                 if (find_next_key(path, 0, &key) == 0 &&
1651                     key.objectid == bytenr &&
1652                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1653                         err = -EAGAIN;
1654                         goto out;
1655                 }
1656         }
1657         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1658 out:
1659         if (insert) {
1660                 path->keep_locks = 0;
1661                 btrfs_unlock_up_safe(path, 1);
1662         }
1663         return err;
1664 }
1665
1666 /*
1667  * helper to add new inline back ref
1668  */
1669 static noinline_for_stack
1670 void setup_inline_extent_backref(struct btrfs_root *root,
1671                                  struct btrfs_path *path,
1672                                  struct btrfs_extent_inline_ref *iref,
1673                                  u64 parent, u64 root_objectid,
1674                                  u64 owner, u64 offset, int refs_to_add,
1675                                  struct btrfs_delayed_extent_op *extent_op)
1676 {
1677         struct extent_buffer *leaf;
1678         struct btrfs_extent_item *ei;
1679         unsigned long ptr;
1680         unsigned long end;
1681         unsigned long item_offset;
1682         u64 refs;
1683         int size;
1684         int type;
1685
1686         leaf = path->nodes[0];
1687         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1688         item_offset = (unsigned long)iref - (unsigned long)ei;
1689
1690         type = extent_ref_type(parent, owner);
1691         size = btrfs_extent_inline_ref_size(type);
1692
1693         btrfs_extend_item(root, path, size);
1694
1695         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1696         refs = btrfs_extent_refs(leaf, ei);
1697         refs += refs_to_add;
1698         btrfs_set_extent_refs(leaf, ei, refs);
1699         if (extent_op)
1700                 __run_delayed_extent_op(extent_op, leaf, ei);
1701
1702         ptr = (unsigned long)ei + item_offset;
1703         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1704         if (ptr < end - size)
1705                 memmove_extent_buffer(leaf, ptr + size, ptr,
1706                                       end - size - ptr);
1707
1708         iref = (struct btrfs_extent_inline_ref *)ptr;
1709         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1710         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1711                 struct btrfs_extent_data_ref *dref;
1712                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1713                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1714                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1715                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1716                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1717         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1718                 struct btrfs_shared_data_ref *sref;
1719                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1720                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1722         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1723                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1724         } else {
1725                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1726         }
1727         btrfs_mark_buffer_dirty(leaf);
1728 }
1729
1730 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1731                                  struct btrfs_root *root,
1732                                  struct btrfs_path *path,
1733                                  struct btrfs_extent_inline_ref **ref_ret,
1734                                  u64 bytenr, u64 num_bytes, u64 parent,
1735                                  u64 root_objectid, u64 owner, u64 offset)
1736 {
1737         int ret;
1738
1739         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1740                                            bytenr, num_bytes, parent,
1741                                            root_objectid, owner, offset, 0);
1742         if (ret != -ENOENT)
1743                 return ret;
1744
1745         btrfs_release_path(path);
1746         *ref_ret = NULL;
1747
1748         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1749                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1750                                             root_objectid);
1751         } else {
1752                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1753                                              root_objectid, owner, offset);
1754         }
1755         return ret;
1756 }
1757
1758 /*
1759  * helper to update/remove inline back ref
1760  */
1761 static noinline_for_stack
1762 void update_inline_extent_backref(struct btrfs_root *root,
1763                                   struct btrfs_path *path,
1764                                   struct btrfs_extent_inline_ref *iref,
1765                                   int refs_to_mod,
1766                                   struct btrfs_delayed_extent_op *extent_op)
1767 {
1768         struct extent_buffer *leaf;
1769         struct btrfs_extent_item *ei;
1770         struct btrfs_extent_data_ref *dref = NULL;
1771         struct btrfs_shared_data_ref *sref = NULL;
1772         unsigned long ptr;
1773         unsigned long end;
1774         u32 item_size;
1775         int size;
1776         int type;
1777         u64 refs;
1778
1779         leaf = path->nodes[0];
1780         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1781         refs = btrfs_extent_refs(leaf, ei);
1782         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1783         refs += refs_to_mod;
1784         btrfs_set_extent_refs(leaf, ei, refs);
1785         if (extent_op)
1786                 __run_delayed_extent_op(extent_op, leaf, ei);
1787
1788         type = btrfs_extent_inline_ref_type(leaf, iref);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 size =  btrfs_extent_inline_ref_size(type);
1811                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1812                 ptr = (unsigned long)iref;
1813                 end = (unsigned long)ei + item_size;
1814                 if (ptr + size < end)
1815                         memmove_extent_buffer(leaf, ptr, ptr + size,
1816                                               end - ptr - size);
1817                 item_size -= size;
1818                 btrfs_truncate_item(root, path, item_size, 1);
1819         }
1820         btrfs_mark_buffer_dirty(leaf);
1821 }
1822
1823 static noinline_for_stack
1824 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1825                                  struct btrfs_root *root,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1836                                            bytenr, num_bytes, parent,
1837                                            root_objectid, owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(root, path, iref,
1841                                              refs_to_add, extent_op);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(root, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_root *root,
1853                                  struct btrfs_path *path,
1854                                  u64 bytenr, u64 parent, u64 root_objectid,
1855                                  u64 owner, u64 offset, int refs_to_add)
1856 {
1857         int ret;
1858         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1859                 BUG_ON(refs_to_add != 1);
1860                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1861                                             parent, root_objectid);
1862         } else {
1863                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1864                                              parent, root_objectid,
1865                                              owner, offset, refs_to_add);
1866         }
1867         return ret;
1868 }
1869
1870 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1871                                  struct btrfs_root *root,
1872                                  struct btrfs_path *path,
1873                                  struct btrfs_extent_inline_ref *iref,
1874                                  int refs_to_drop, int is_data)
1875 {
1876         int ret = 0;
1877
1878         BUG_ON(!is_data && refs_to_drop != 1);
1879         if (iref) {
1880                 update_inline_extent_backref(root, path, iref,
1881                                              -refs_to_drop, NULL);
1882         } else if (is_data) {
1883                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1884         } else {
1885                 ret = btrfs_del_item(trans, root, path);
1886         }
1887         return ret;
1888 }
1889
1890 static int btrfs_issue_discard(struct block_device *bdev,
1891                                 u64 start, u64 len)
1892 {
1893         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1894 }
1895
1896 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1897                                 u64 num_bytes, u64 *actual_bytes)
1898 {
1899         int ret;
1900         u64 discarded_bytes = 0;
1901         struct btrfs_bio *bbio = NULL;
1902
1903
1904         /* Tell the block device(s) that the sectors can be discarded */
1905         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1906                               bytenr, &num_bytes, &bbio, 0);
1907         /* Error condition is -ENOMEM */
1908         if (!ret) {
1909                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1910                 int i;
1911
1912
1913                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1914                         if (!stripe->dev->can_discard)
1915                                 continue;
1916
1917                         ret = btrfs_issue_discard(stripe->dev->bdev,
1918                                                   stripe->physical,
1919                                                   stripe->length);
1920                         if (!ret)
1921                                 discarded_bytes += stripe->length;
1922                         else if (ret != -EOPNOTSUPP)
1923                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1924
1925                         /*
1926                          * Just in case we get back EOPNOTSUPP for some reason,
1927                          * just ignore the return value so we don't screw up
1928                          * people calling discard_extent.
1929                          */
1930                         ret = 0;
1931                 }
1932                 kfree(bbio);
1933         }
1934
1935         if (actual_bytes)
1936                 *actual_bytes = discarded_bytes;
1937
1938
1939         if (ret == -EOPNOTSUPP)
1940                 ret = 0;
1941         return ret;
1942 }
1943
1944 /* Can return -ENOMEM */
1945 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1946                          struct btrfs_root *root,
1947                          u64 bytenr, u64 num_bytes, u64 parent,
1948                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1949 {
1950         int ret;
1951         struct btrfs_fs_info *fs_info = root->fs_info;
1952
1953         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1954                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1955
1956         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1957                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1958                                         num_bytes,
1959                                         parent, root_objectid, (int)owner,
1960                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1961         } else {
1962                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1963                                         num_bytes,
1964                                         parent, root_objectid, owner, offset,
1965                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1966         }
1967         return ret;
1968 }
1969
1970 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1971                                   struct btrfs_root *root,
1972                                   u64 bytenr, u64 num_bytes,
1973                                   u64 parent, u64 root_objectid,
1974                                   u64 owner, u64 offset, int refs_to_add,
1975                                   struct btrfs_delayed_extent_op *extent_op)
1976 {
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         u64 refs;
1981         int ret;
1982         int err = 0;
1983
1984         path = btrfs_alloc_path();
1985         if (!path)
1986                 return -ENOMEM;
1987
1988         path->reada = 1;
1989         path->leave_spinning = 1;
1990         /* this will setup the path even if it fails to insert the back ref */
1991         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1992                                            path, bytenr, num_bytes, parent,
1993                                            root_objectid, owner, offset,
1994                                            refs_to_add, extent_op);
1995         if (ret == 0)
1996                 goto out;
1997
1998         if (ret != -EAGAIN) {
1999                 err = ret;
2000                 goto out;
2001         }
2002
2003         leaf = path->nodes[0];
2004         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2005         refs = btrfs_extent_refs(leaf, item);
2006         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2007         if (extent_op)
2008                 __run_delayed_extent_op(extent_op, leaf, item);
2009
2010         btrfs_mark_buffer_dirty(leaf);
2011         btrfs_release_path(path);
2012
2013         path->reada = 1;
2014         path->leave_spinning = 1;
2015
2016         /* now insert the actual backref */
2017         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2018                                     path, bytenr, parent, root_objectid,
2019                                     owner, offset, refs_to_add);
2020         if (ret)
2021                 btrfs_abort_transaction(trans, root, ret);
2022 out:
2023         btrfs_free_path(path);
2024         return err;
2025 }
2026
2027 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2028                                 struct btrfs_root *root,
2029                                 struct btrfs_delayed_ref_node *node,
2030                                 struct btrfs_delayed_extent_op *extent_op,
2031                                 int insert_reserved)
2032 {
2033         int ret = 0;
2034         struct btrfs_delayed_data_ref *ref;
2035         struct btrfs_key ins;
2036         u64 parent = 0;
2037         u64 ref_root = 0;
2038         u64 flags = 0;
2039
2040         ins.objectid = node->bytenr;
2041         ins.offset = node->num_bytes;
2042         ins.type = BTRFS_EXTENT_ITEM_KEY;
2043
2044         ref = btrfs_delayed_node_to_data_ref(node);
2045         trace_run_delayed_data_ref(node, ref, node->action);
2046
2047         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2048                 parent = ref->parent;
2049         else
2050                 ref_root = ref->root;
2051
2052         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2053                 if (extent_op)
2054                         flags |= extent_op->flags_to_set;
2055                 ret = alloc_reserved_file_extent(trans, root,
2056                                                  parent, ref_root, flags,
2057                                                  ref->objectid, ref->offset,
2058                                                  &ins, node->ref_mod);
2059         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2060                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2061                                              node->num_bytes, parent,
2062                                              ref_root, ref->objectid,
2063                                              ref->offset, node->ref_mod,
2064                                              extent_op);
2065         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2066                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2067                                           node->num_bytes, parent,
2068                                           ref_root, ref->objectid,
2069                                           ref->offset, node->ref_mod,
2070                                           extent_op);
2071         } else {
2072                 BUG();
2073         }
2074         return ret;
2075 }
2076
2077 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2078                                     struct extent_buffer *leaf,
2079                                     struct btrfs_extent_item *ei)
2080 {
2081         u64 flags = btrfs_extent_flags(leaf, ei);
2082         if (extent_op->update_flags) {
2083                 flags |= extent_op->flags_to_set;
2084                 btrfs_set_extent_flags(leaf, ei, flags);
2085         }
2086
2087         if (extent_op->update_key) {
2088                 struct btrfs_tree_block_info *bi;
2089                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2090                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2091                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2092         }
2093 }
2094
2095 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2096                                  struct btrfs_root *root,
2097                                  struct btrfs_delayed_ref_node *node,
2098                                  struct btrfs_delayed_extent_op *extent_op)
2099 {
2100         struct btrfs_key key;
2101         struct btrfs_path *path;
2102         struct btrfs_extent_item *ei;
2103         struct extent_buffer *leaf;
2104         u32 item_size;
2105         int ret;
2106         int err = 0;
2107         int metadata = !extent_op->is_data;
2108
2109         if (trans->aborted)
2110                 return 0;
2111
2112         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2113                 metadata = 0;
2114
2115         path = btrfs_alloc_path();
2116         if (!path)
2117                 return -ENOMEM;
2118
2119         key.objectid = node->bytenr;
2120
2121         if (metadata) {
2122                 key.type = BTRFS_METADATA_ITEM_KEY;
2123                 key.offset = extent_op->level;
2124         } else {
2125                 key.type = BTRFS_EXTENT_ITEM_KEY;
2126                 key.offset = node->num_bytes;
2127         }
2128
2129 again:
2130         path->reada = 1;
2131         path->leave_spinning = 1;
2132         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2133                                 path, 0, 1);
2134         if (ret < 0) {
2135                 err = ret;
2136                 goto out;
2137         }
2138         if (ret > 0) {
2139                 if (metadata) {
2140                         btrfs_release_path(path);
2141                         metadata = 0;
2142
2143                         key.offset = node->num_bytes;
2144                         key.type = BTRFS_EXTENT_ITEM_KEY;
2145                         goto again;
2146                 }
2147                 err = -EIO;
2148                 goto out;
2149         }
2150
2151         leaf = path->nodes[0];
2152         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2153 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2154         if (item_size < sizeof(*ei)) {
2155                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2156                                              path, (u64)-1, 0);
2157                 if (ret < 0) {
2158                         err = ret;
2159                         goto out;
2160                 }
2161                 leaf = path->nodes[0];
2162                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2163         }
2164 #endif
2165         BUG_ON(item_size < sizeof(*ei));
2166         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2167         __run_delayed_extent_op(extent_op, leaf, ei);
2168
2169         btrfs_mark_buffer_dirty(leaf);
2170 out:
2171         btrfs_free_path(path);
2172         return err;
2173 }
2174
2175 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2176                                 struct btrfs_root *root,
2177                                 struct btrfs_delayed_ref_node *node,
2178                                 struct btrfs_delayed_extent_op *extent_op,
2179                                 int insert_reserved)
2180 {
2181         int ret = 0;
2182         struct btrfs_delayed_tree_ref *ref;
2183         struct btrfs_key ins;
2184         u64 parent = 0;
2185         u64 ref_root = 0;
2186         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2187                                                  SKINNY_METADATA);
2188
2189         ref = btrfs_delayed_node_to_tree_ref(node);
2190         trace_run_delayed_tree_ref(node, ref, node->action);
2191
2192         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2193                 parent = ref->parent;
2194         else
2195                 ref_root = ref->root;
2196
2197         ins.objectid = node->bytenr;
2198         if (skinny_metadata) {
2199                 ins.offset = ref->level;
2200                 ins.type = BTRFS_METADATA_ITEM_KEY;
2201         } else {
2202                 ins.offset = node->num_bytes;
2203                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2204         }
2205
2206         BUG_ON(node->ref_mod != 1);
2207         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2208                 BUG_ON(!extent_op || !extent_op->update_flags);
2209                 ret = alloc_reserved_tree_block(trans, root,
2210                                                 parent, ref_root,
2211                                                 extent_op->flags_to_set,
2212                                                 &extent_op->key,
2213                                                 ref->level, &ins);
2214         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2215                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2216                                              node->num_bytes, parent, ref_root,
2217                                              ref->level, 0, 1, extent_op);
2218         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2219                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2220                                           node->num_bytes, parent, ref_root,
2221                                           ref->level, 0, 1, extent_op);
2222         } else {
2223                 BUG();
2224         }
2225         return ret;
2226 }
2227
2228 /* helper function to actually process a single delayed ref entry */
2229 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2230                                struct btrfs_root *root,
2231                                struct btrfs_delayed_ref_node *node,
2232                                struct btrfs_delayed_extent_op *extent_op,
2233                                int insert_reserved)
2234 {
2235         int ret = 0;
2236
2237         if (trans->aborted)
2238                 return 0;
2239
2240         if (btrfs_delayed_ref_is_head(node)) {
2241                 struct btrfs_delayed_ref_head *head;
2242                 /*
2243                  * we've hit the end of the chain and we were supposed
2244                  * to insert this extent into the tree.  But, it got
2245                  * deleted before we ever needed to insert it, so all
2246                  * we have to do is clean up the accounting
2247                  */
2248                 BUG_ON(extent_op);
2249                 head = btrfs_delayed_node_to_head(node);
2250                 trace_run_delayed_ref_head(node, head, node->action);
2251
2252                 if (insert_reserved) {
2253                         btrfs_pin_extent(root, node->bytenr,
2254                                          node->num_bytes, 1);
2255                         if (head->is_data) {
2256                                 ret = btrfs_del_csums(trans, root,
2257                                                       node->bytenr,
2258                                                       node->num_bytes);
2259                         }
2260                 }
2261                 return ret;
2262         }
2263
2264         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2265             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2266                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2267                                            insert_reserved);
2268         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2269                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2270                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2271                                            insert_reserved);
2272         else
2273                 BUG();
2274         return ret;
2275 }
2276
2277 static noinline struct btrfs_delayed_ref_node *
2278 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2279 {
2280         struct rb_node *node;
2281         struct btrfs_delayed_ref_node *ref;
2282         int action = BTRFS_ADD_DELAYED_REF;
2283 again:
2284         /*
2285          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2286          * this prevents ref count from going down to zero when
2287          * there still are pending delayed ref.
2288          */
2289         node = rb_prev(&head->node.rb_node);
2290         while (1) {
2291                 if (!node)
2292                         break;
2293                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2294                                 rb_node);
2295                 if (ref->bytenr != head->node.bytenr)
2296                         break;
2297                 if (ref->action == action)
2298                         return ref;
2299                 node = rb_prev(node);
2300         }
2301         if (action == BTRFS_ADD_DELAYED_REF) {
2302                 action = BTRFS_DROP_DELAYED_REF;
2303                 goto again;
2304         }
2305         return NULL;
2306 }
2307
2308 /*
2309  * Returns 0 on success or if called with an already aborted transaction.
2310  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2311  */
2312 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2313                                        struct btrfs_root *root,
2314                                        struct list_head *cluster)
2315 {
2316         struct btrfs_delayed_ref_root *delayed_refs;
2317         struct btrfs_delayed_ref_node *ref;
2318         struct btrfs_delayed_ref_head *locked_ref = NULL;
2319         struct btrfs_delayed_extent_op *extent_op;
2320         struct btrfs_fs_info *fs_info = root->fs_info;
2321         int ret;
2322         int count = 0;
2323         int must_insert_reserved = 0;
2324
2325         delayed_refs = &trans->transaction->delayed_refs;
2326         while (1) {
2327                 if (!locked_ref) {
2328                         /* pick a new head ref from the cluster list */
2329                         if (list_empty(cluster))
2330                                 break;
2331
2332                         locked_ref = list_entry(cluster->next,
2333                                      struct btrfs_delayed_ref_head, cluster);
2334
2335                         /* grab the lock that says we are going to process
2336                          * all the refs for this head */
2337                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2338
2339                         /*
2340                          * we may have dropped the spin lock to get the head
2341                          * mutex lock, and that might have given someone else
2342                          * time to free the head.  If that's true, it has been
2343                          * removed from our list and we can move on.
2344                          */
2345                         if (ret == -EAGAIN) {
2346                                 locked_ref = NULL;
2347                                 count++;
2348                                 continue;
2349                         }
2350                 }
2351
2352                 /*
2353                  * We need to try and merge add/drops of the same ref since we
2354                  * can run into issues with relocate dropping the implicit ref
2355                  * and then it being added back again before the drop can
2356                  * finish.  If we merged anything we need to re-loop so we can
2357                  * get a good ref.
2358                  */
2359                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2360                                          locked_ref);
2361
2362                 /*
2363                  * locked_ref is the head node, so we have to go one
2364                  * node back for any delayed ref updates
2365                  */
2366                 ref = select_delayed_ref(locked_ref);
2367
2368                 if (ref && ref->seq &&
2369                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2370                         /*
2371                          * there are still refs with lower seq numbers in the
2372                          * process of being added. Don't run this ref yet.
2373                          */
2374                         list_del_init(&locked_ref->cluster);
2375                         btrfs_delayed_ref_unlock(locked_ref);
2376                         locked_ref = NULL;
2377                         delayed_refs->num_heads_ready++;
2378                         spin_unlock(&delayed_refs->lock);
2379                         cond_resched();
2380                         spin_lock(&delayed_refs->lock);
2381                         continue;
2382                 }
2383
2384                 /*
2385                  * record the must insert reserved flag before we
2386                  * drop the spin lock.
2387                  */
2388                 must_insert_reserved = locked_ref->must_insert_reserved;
2389                 locked_ref->must_insert_reserved = 0;
2390
2391                 extent_op = locked_ref->extent_op;
2392                 locked_ref->extent_op = NULL;
2393
2394                 if (!ref) {
2395                         /* All delayed refs have been processed, Go ahead
2396                          * and send the head node to run_one_delayed_ref,
2397                          * so that any accounting fixes can happen
2398                          */
2399                         ref = &locked_ref->node;
2400
2401                         if (extent_op && must_insert_reserved) {
2402                                 btrfs_free_delayed_extent_op(extent_op);
2403                                 extent_op = NULL;
2404                         }
2405
2406                         if (extent_op) {
2407                                 spin_unlock(&delayed_refs->lock);
2408
2409                                 ret = run_delayed_extent_op(trans, root,
2410                                                             ref, extent_op);
2411                                 btrfs_free_delayed_extent_op(extent_op);
2412
2413                                 if (ret) {
2414                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2415                                         spin_lock(&delayed_refs->lock);
2416                                         btrfs_delayed_ref_unlock(locked_ref);
2417                                         return ret;
2418                                 }
2419
2420                                 goto next;
2421                         }
2422                 }
2423
2424                 ref->in_tree = 0;
2425                 rb_erase(&ref->rb_node, &delayed_refs->root);
2426                 delayed_refs->num_entries--;
2427                 if (!btrfs_delayed_ref_is_head(ref)) {
2428                         /*
2429                          * when we play the delayed ref, also correct the
2430                          * ref_mod on head
2431                          */
2432                         switch (ref->action) {
2433                         case BTRFS_ADD_DELAYED_REF:
2434                         case BTRFS_ADD_DELAYED_EXTENT:
2435                                 locked_ref->node.ref_mod -= ref->ref_mod;
2436                                 break;
2437                         case BTRFS_DROP_DELAYED_REF:
2438                                 locked_ref->node.ref_mod += ref->ref_mod;
2439                                 break;
2440                         default:
2441                                 WARN_ON(1);
2442                         }
2443                 }
2444                 spin_unlock(&delayed_refs->lock);
2445
2446                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2447                                           must_insert_reserved);
2448
2449                 btrfs_free_delayed_extent_op(extent_op);
2450                 if (ret) {
2451                         btrfs_delayed_ref_unlock(locked_ref);
2452                         btrfs_put_delayed_ref(ref);
2453                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2454                         spin_lock(&delayed_refs->lock);
2455                         return ret;
2456                 }
2457
2458                 /*
2459                  * If this node is a head, that means all the refs in this head
2460                  * have been dealt with, and we will pick the next head to deal
2461                  * with, so we must unlock the head and drop it from the cluster
2462                  * list before we release it.
2463                  */
2464                 if (btrfs_delayed_ref_is_head(ref)) {
2465                         list_del_init(&locked_ref->cluster);
2466                         btrfs_delayed_ref_unlock(locked_ref);
2467                         locked_ref = NULL;
2468                 }
2469                 btrfs_put_delayed_ref(ref);
2470                 count++;
2471 next:
2472                 cond_resched();
2473                 spin_lock(&delayed_refs->lock);
2474         }
2475         return count;
2476 }
2477
2478 #ifdef SCRAMBLE_DELAYED_REFS
2479 /*
2480  * Normally delayed refs get processed in ascending bytenr order. This
2481  * correlates in most cases to the order added. To expose dependencies on this
2482  * order, we start to process the tree in the middle instead of the beginning
2483  */
2484 static u64 find_middle(struct rb_root *root)
2485 {
2486         struct rb_node *n = root->rb_node;
2487         struct btrfs_delayed_ref_node *entry;
2488         int alt = 1;
2489         u64 middle;
2490         u64 first = 0, last = 0;
2491
2492         n = rb_first(root);
2493         if (n) {
2494                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2495                 first = entry->bytenr;
2496         }
2497         n = rb_last(root);
2498         if (n) {
2499                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2500                 last = entry->bytenr;
2501         }
2502         n = root->rb_node;
2503
2504         while (n) {
2505                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2506                 WARN_ON(!entry->in_tree);
2507
2508                 middle = entry->bytenr;
2509
2510                 if (alt)
2511                         n = n->rb_left;
2512                 else
2513                         n = n->rb_right;
2514
2515                 alt = 1 - alt;
2516         }
2517         return middle;
2518 }
2519 #endif
2520
2521 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2522                                          struct btrfs_fs_info *fs_info)
2523 {
2524         struct qgroup_update *qgroup_update;
2525         int ret = 0;
2526
2527         if (list_empty(&trans->qgroup_ref_list) !=
2528             !trans->delayed_ref_elem.seq) {
2529                 /* list without seq or seq without list */
2530                 btrfs_err(fs_info,
2531                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2532                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2533                         (u32)(trans->delayed_ref_elem.seq >> 32),
2534                         (u32)trans->delayed_ref_elem.seq);
2535                 BUG();
2536         }
2537
2538         if (!trans->delayed_ref_elem.seq)
2539                 return 0;
2540
2541         while (!list_empty(&trans->qgroup_ref_list)) {
2542                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2543                                                  struct qgroup_update, list);
2544                 list_del(&qgroup_update->list);
2545                 if (!ret)
2546                         ret = btrfs_qgroup_account_ref(
2547                                         trans, fs_info, qgroup_update->node,
2548                                         qgroup_update->extent_op);
2549                 kfree(qgroup_update);
2550         }
2551
2552         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2553
2554         return ret;
2555 }
2556
2557 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2558                       int count)
2559 {
2560         int val = atomic_read(&delayed_refs->ref_seq);
2561
2562         if (val < seq || val >= seq + count)
2563                 return 1;
2564         return 0;
2565 }
2566
2567 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2568 {
2569         u64 num_bytes;
2570
2571         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2572                              sizeof(struct btrfs_extent_inline_ref));
2573         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2574                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2575
2576         /*
2577          * We don't ever fill up leaves all the way so multiply by 2 just to be
2578          * closer to what we're really going to want to ouse.
2579          */
2580         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2581 }
2582
2583 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2584                                        struct btrfs_root *root)
2585 {
2586         struct btrfs_block_rsv *global_rsv;
2587         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2588         u64 num_bytes;
2589         int ret = 0;
2590
2591         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2592         num_heads = heads_to_leaves(root, num_heads);
2593         if (num_heads > 1)
2594                 num_bytes += (num_heads - 1) * root->leafsize;
2595         num_bytes <<= 1;
2596         global_rsv = &root->fs_info->global_block_rsv;
2597
2598         /*
2599          * If we can't allocate any more chunks lets make sure we have _lots_ of
2600          * wiggle room since running delayed refs can create more delayed refs.
2601          */
2602         if (global_rsv->space_info->full)
2603                 num_bytes <<= 1;
2604
2605         spin_lock(&global_rsv->lock);
2606         if (global_rsv->reserved <= num_bytes)
2607                 ret = 1;
2608         spin_unlock(&global_rsv->lock);
2609         return ret;
2610 }
2611
2612 /*
2613  * this starts processing the delayed reference count updates and
2614  * extent insertions we have queued up so far.  count can be
2615  * 0, which means to process everything in the tree at the start
2616  * of the run (but not newly added entries), or it can be some target
2617  * number you'd like to process.
2618  *
2619  * Returns 0 on success or if called with an aborted transaction
2620  * Returns <0 on error and aborts the transaction
2621  */
2622 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2623                            struct btrfs_root *root, unsigned long count)
2624 {
2625         struct rb_node *node;
2626         struct btrfs_delayed_ref_root *delayed_refs;
2627         struct btrfs_delayed_ref_node *ref;
2628         struct list_head cluster;
2629         int ret;
2630         u64 delayed_start;
2631         int run_all = count == (unsigned long)-1;
2632         int run_most = 0;
2633         int loops;
2634
2635         /* We'll clean this up in btrfs_cleanup_transaction */
2636         if (trans->aborted)
2637                 return 0;
2638
2639         if (root == root->fs_info->extent_root)
2640                 root = root->fs_info->tree_root;
2641
2642         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2643
2644         delayed_refs = &trans->transaction->delayed_refs;
2645         INIT_LIST_HEAD(&cluster);
2646         if (count == 0) {
2647                 count = delayed_refs->num_entries * 2;
2648                 run_most = 1;
2649         }
2650
2651         if (!run_all && !run_most) {
2652                 int old;
2653                 int seq = atomic_read(&delayed_refs->ref_seq);
2654
2655 progress:
2656                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2657                 if (old) {
2658                         DEFINE_WAIT(__wait);
2659                         if (delayed_refs->flushing ||
2660                             !btrfs_should_throttle_delayed_refs(trans, root))
2661                                 return 0;
2662
2663                         prepare_to_wait(&delayed_refs->wait, &__wait,
2664                                         TASK_UNINTERRUPTIBLE);
2665
2666                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2667                         if (old) {
2668                                 schedule();
2669                                 finish_wait(&delayed_refs->wait, &__wait);
2670
2671                                 if (!refs_newer(delayed_refs, seq, 256))
2672                                         goto progress;
2673                                 else
2674                                         return 0;
2675                         } else {
2676                                 finish_wait(&delayed_refs->wait, &__wait);
2677                                 goto again;
2678                         }
2679                 }
2680
2681         } else {
2682                 atomic_inc(&delayed_refs->procs_running_refs);
2683         }
2684
2685 again:
2686         loops = 0;
2687         spin_lock(&delayed_refs->lock);
2688
2689 #ifdef SCRAMBLE_DELAYED_REFS
2690         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2691 #endif
2692
2693         while (1) {
2694                 if (!(run_all || run_most) &&
2695                     !btrfs_should_throttle_delayed_refs(trans, root))
2696                         break;
2697
2698                 /*
2699                  * go find something we can process in the rbtree.  We start at
2700                  * the beginning of the tree, and then build a cluster
2701                  * of refs to process starting at the first one we are able to
2702                  * lock
2703                  */
2704                 delayed_start = delayed_refs->run_delayed_start;
2705                 ret = btrfs_find_ref_cluster(trans, &cluster,
2706                                              delayed_refs->run_delayed_start);
2707                 if (ret)
2708                         break;
2709
2710                 ret = run_clustered_refs(trans, root, &cluster);
2711                 if (ret < 0) {
2712                         btrfs_release_ref_cluster(&cluster);
2713                         spin_unlock(&delayed_refs->lock);
2714                         btrfs_abort_transaction(trans, root, ret);
2715                         atomic_dec(&delayed_refs->procs_running_refs);
2716                         wake_up(&delayed_refs->wait);
2717                         return ret;
2718                 }
2719
2720                 atomic_add(ret, &delayed_refs->ref_seq);
2721
2722                 count -= min_t(unsigned long, ret, count);
2723
2724                 if (count == 0)
2725                         break;
2726
2727                 if (delayed_start >= delayed_refs->run_delayed_start) {
2728                         if (loops == 0) {
2729                                 /*
2730                                  * btrfs_find_ref_cluster looped. let's do one
2731                                  * more cycle. if we don't run any delayed ref
2732                                  * during that cycle (because we can't because
2733                                  * all of them are blocked), bail out.
2734                                  */
2735                                 loops = 1;
2736                         } else {
2737                                 /*
2738                                  * no runnable refs left, stop trying
2739                                  */
2740                                 BUG_ON(run_all);
2741                                 break;
2742                         }
2743                 }
2744                 if (ret) {
2745                         /* refs were run, let's reset staleness detection */
2746                         loops = 0;
2747                 }
2748         }
2749
2750         if (run_all) {
2751                 if (!list_empty(&trans->new_bgs)) {
2752                         spin_unlock(&delayed_refs->lock);
2753                         btrfs_create_pending_block_groups(trans, root);
2754                         spin_lock(&delayed_refs->lock);
2755                 }
2756
2757                 node = rb_first(&delayed_refs->root);
2758                 if (!node)
2759                         goto out;
2760                 count = (unsigned long)-1;
2761
2762                 while (node) {
2763                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2764                                        rb_node);
2765                         if (btrfs_delayed_ref_is_head(ref)) {
2766                                 struct btrfs_delayed_ref_head *head;
2767
2768                                 head = btrfs_delayed_node_to_head(ref);
2769                                 atomic_inc(&ref->refs);
2770
2771                                 spin_unlock(&delayed_refs->lock);
2772                                 /*
2773                                  * Mutex was contended, block until it's
2774                                  * released and try again
2775                                  */
2776                                 mutex_lock(&head->mutex);
2777                                 mutex_unlock(&head->mutex);
2778
2779                                 btrfs_put_delayed_ref(ref);
2780                                 cond_resched();
2781                                 goto again;
2782                         }
2783                         node = rb_next(node);
2784                 }
2785                 spin_unlock(&delayed_refs->lock);
2786                 schedule_timeout(1);
2787                 goto again;
2788         }
2789 out:
2790         atomic_dec(&delayed_refs->procs_running_refs);
2791         smp_mb();
2792         if (waitqueue_active(&delayed_refs->wait))
2793                 wake_up(&delayed_refs->wait);
2794
2795         spin_unlock(&delayed_refs->lock);
2796         assert_qgroups_uptodate(trans);
2797         return 0;
2798 }
2799
2800 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2801                                 struct btrfs_root *root,
2802                                 u64 bytenr, u64 num_bytes, u64 flags,
2803                                 int level, int is_data)
2804 {
2805         struct btrfs_delayed_extent_op *extent_op;
2806         int ret;
2807
2808         extent_op = btrfs_alloc_delayed_extent_op();
2809         if (!extent_op)
2810                 return -ENOMEM;
2811
2812         extent_op->flags_to_set = flags;
2813         extent_op->update_flags = 1;
2814         extent_op->update_key = 0;
2815         extent_op->is_data = is_data ? 1 : 0;
2816         extent_op->level = level;
2817
2818         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2819                                           num_bytes, extent_op);
2820         if (ret)
2821                 btrfs_free_delayed_extent_op(extent_op);
2822         return ret;
2823 }
2824
2825 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2826                                       struct btrfs_root *root,
2827                                       struct btrfs_path *path,
2828                                       u64 objectid, u64 offset, u64 bytenr)
2829 {
2830         struct btrfs_delayed_ref_head *head;
2831         struct btrfs_delayed_ref_node *ref;
2832         struct btrfs_delayed_data_ref *data_ref;
2833         struct btrfs_delayed_ref_root *delayed_refs;
2834         struct rb_node *node;
2835         int ret = 0;
2836
2837         ret = -ENOENT;
2838         delayed_refs = &trans->transaction->delayed_refs;
2839         spin_lock(&delayed_refs->lock);
2840         head = btrfs_find_delayed_ref_head(trans, bytenr);
2841         if (!head)
2842                 goto out;
2843
2844         if (!mutex_trylock(&head->mutex)) {
2845                 atomic_inc(&head->node.refs);
2846                 spin_unlock(&delayed_refs->lock);
2847
2848                 btrfs_release_path(path);
2849
2850                 /*
2851                  * Mutex was contended, block until it's released and let
2852                  * caller try again
2853                  */
2854                 mutex_lock(&head->mutex);
2855                 mutex_unlock(&head->mutex);
2856                 btrfs_put_delayed_ref(&head->node);
2857                 return -EAGAIN;
2858         }
2859
2860         node = rb_prev(&head->node.rb_node);
2861         if (!node)
2862                 goto out_unlock;
2863
2864         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2865
2866         if (ref->bytenr != bytenr)
2867                 goto out_unlock;
2868
2869         ret = 1;
2870         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2871                 goto out_unlock;
2872
2873         data_ref = btrfs_delayed_node_to_data_ref(ref);
2874
2875         node = rb_prev(node);
2876         if (node) {
2877                 int seq = ref->seq;
2878
2879                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2880                 if (ref->bytenr == bytenr && ref->seq == seq)
2881                         goto out_unlock;
2882         }
2883
2884         if (data_ref->root != root->root_key.objectid ||
2885             data_ref->objectid != objectid || data_ref->offset != offset)
2886                 goto out_unlock;
2887
2888         ret = 0;
2889 out_unlock:
2890         mutex_unlock(&head->mutex);
2891 out:
2892         spin_unlock(&delayed_refs->lock);
2893         return ret;
2894 }
2895
2896 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2897                                         struct btrfs_root *root,
2898                                         struct btrfs_path *path,
2899                                         u64 objectid, u64 offset, u64 bytenr)
2900 {
2901         struct btrfs_root *extent_root = root->fs_info->extent_root;
2902         struct extent_buffer *leaf;
2903         struct btrfs_extent_data_ref *ref;
2904         struct btrfs_extent_inline_ref *iref;
2905         struct btrfs_extent_item *ei;
2906         struct btrfs_key key;
2907         u32 item_size;
2908         int ret;
2909
2910         key.objectid = bytenr;
2911         key.offset = (u64)-1;
2912         key.type = BTRFS_EXTENT_ITEM_KEY;
2913
2914         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2915         if (ret < 0)
2916                 goto out;
2917         BUG_ON(ret == 0); /* Corruption */
2918
2919         ret = -ENOENT;
2920         if (path->slots[0] == 0)
2921                 goto out;
2922
2923         path->slots[0]--;
2924         leaf = path->nodes[0];
2925         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2926
2927         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2928                 goto out;
2929
2930         ret = 1;
2931         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2932 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2933         if (item_size < sizeof(*ei)) {
2934                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2935                 goto out;
2936         }
2937 #endif
2938         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2939
2940         if (item_size != sizeof(*ei) +
2941             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2942                 goto out;
2943
2944         if (btrfs_extent_generation(leaf, ei) <=
2945             btrfs_root_last_snapshot(&root->root_item))
2946                 goto out;
2947
2948         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2949         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2950             BTRFS_EXTENT_DATA_REF_KEY)
2951                 goto out;
2952
2953         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2954         if (btrfs_extent_refs(leaf, ei) !=
2955             btrfs_extent_data_ref_count(leaf, ref) ||
2956             btrfs_extent_data_ref_root(leaf, ref) !=
2957             root->root_key.objectid ||
2958             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2959             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2960                 goto out;
2961
2962         ret = 0;
2963 out:
2964         return ret;
2965 }
2966
2967 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2968                           struct btrfs_root *root,
2969                           u64 objectid, u64 offset, u64 bytenr)
2970 {
2971         struct btrfs_path *path;
2972         int ret;
2973         int ret2;
2974
2975         path = btrfs_alloc_path();
2976         if (!path)
2977                 return -ENOENT;
2978
2979         do {
2980                 ret = check_committed_ref(trans, root, path, objectid,
2981                                           offset, bytenr);
2982                 if (ret && ret != -ENOENT)
2983                         goto out;
2984
2985                 ret2 = check_delayed_ref(trans, root, path, objectid,
2986                                          offset, bytenr);
2987         } while (ret2 == -EAGAIN);
2988
2989         if (ret2 && ret2 != -ENOENT) {
2990                 ret = ret2;
2991                 goto out;
2992         }
2993
2994         if (ret != -ENOENT || ret2 != -ENOENT)
2995                 ret = 0;
2996 out:
2997         btrfs_free_path(path);
2998         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2999                 WARN_ON(ret > 0);
3000         return ret;
3001 }
3002
3003 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3004                            struct btrfs_root *root,
3005                            struct extent_buffer *buf,
3006                            int full_backref, int inc, int for_cow)
3007 {
3008         u64 bytenr;
3009         u64 num_bytes;
3010         u64 parent;
3011         u64 ref_root;
3012         u32 nritems;
3013         struct btrfs_key key;
3014         struct btrfs_file_extent_item *fi;
3015         int i;
3016         int level;
3017         int ret = 0;
3018         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3019                             u64, u64, u64, u64, u64, u64, int);
3020
3021         ref_root = btrfs_header_owner(buf);
3022         nritems = btrfs_header_nritems(buf);
3023         level = btrfs_header_level(buf);
3024
3025         if (!root->ref_cows && level == 0)
3026                 return 0;
3027
3028         if (inc)
3029                 process_func = btrfs_inc_extent_ref;
3030         else
3031                 process_func = btrfs_free_extent;
3032
3033         if (full_backref)
3034                 parent = buf->start;
3035         else
3036                 parent = 0;
3037
3038         for (i = 0; i < nritems; i++) {
3039                 if (level == 0) {
3040                         btrfs_item_key_to_cpu(buf, &key, i);
3041                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3042                                 continue;
3043                         fi = btrfs_item_ptr(buf, i,
3044                                             struct btrfs_file_extent_item);
3045                         if (btrfs_file_extent_type(buf, fi) ==
3046                             BTRFS_FILE_EXTENT_INLINE)
3047                                 continue;
3048                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3049                         if (bytenr == 0)
3050                                 continue;
3051
3052                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3053                         key.offset -= btrfs_file_extent_offset(buf, fi);
3054                         ret = process_func(trans, root, bytenr, num_bytes,
3055                                            parent, ref_root, key.objectid,
3056                                            key.offset, for_cow);
3057                         if (ret)
3058                                 goto fail;
3059                 } else {
3060                         bytenr = btrfs_node_blockptr(buf, i);
3061                         num_bytes = btrfs_level_size(root, level - 1);
3062                         ret = process_func(trans, root, bytenr, num_bytes,
3063                                            parent, ref_root, level - 1, 0,
3064                                            for_cow);
3065                         if (ret)
3066                                 goto fail;
3067                 }
3068         }
3069         return 0;
3070 fail:
3071         return ret;
3072 }
3073
3074 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3075                   struct extent_buffer *buf, int full_backref, int for_cow)
3076 {
3077         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3078 }
3079
3080 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3081                   struct extent_buffer *buf, int full_backref, int for_cow)
3082 {
3083         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3084 }
3085
3086 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3087                                  struct btrfs_root *root,
3088                                  struct btrfs_path *path,
3089                                  struct btrfs_block_group_cache *cache)
3090 {
3091         int ret;
3092         struct btrfs_root *extent_root = root->fs_info->extent_root;
3093         unsigned long bi;
3094         struct extent_buffer *leaf;
3095
3096         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3097         if (ret < 0)
3098                 goto fail;
3099         BUG_ON(ret); /* Corruption */
3100
3101         leaf = path->nodes[0];
3102         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3103         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3104         btrfs_mark_buffer_dirty(leaf);
3105         btrfs_release_path(path);
3106 fail:
3107         if (ret) {
3108                 btrfs_abort_transaction(trans, root, ret);
3109                 return ret;
3110         }
3111         return 0;
3112
3113 }
3114
3115 static struct btrfs_block_group_cache *
3116 next_block_group(struct btrfs_root *root,
3117                  struct btrfs_block_group_cache *cache)
3118 {
3119         struct rb_node *node;
3120         spin_lock(&root->fs_info->block_group_cache_lock);
3121         node = rb_next(&cache->cache_node);
3122         btrfs_put_block_group(cache);
3123         if (node) {
3124                 cache = rb_entry(node, struct btrfs_block_group_cache,
3125                                  cache_node);
3126                 btrfs_get_block_group(cache);
3127         } else
3128                 cache = NULL;
3129         spin_unlock(&root->fs_info->block_group_cache_lock);
3130         return cache;
3131 }
3132
3133 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3134                             struct btrfs_trans_handle *trans,
3135                             struct btrfs_path *path)
3136 {
3137         struct btrfs_root *root = block_group->fs_info->tree_root;
3138         struct inode *inode = NULL;
3139         u64 alloc_hint = 0;
3140         int dcs = BTRFS_DC_ERROR;
3141         int num_pages = 0;
3142         int retries = 0;
3143         int ret = 0;
3144
3145         /*
3146          * If this block group is smaller than 100 megs don't bother caching the
3147          * block group.
3148          */
3149         if (block_group->key.offset < (100 * 1024 * 1024)) {
3150                 spin_lock(&block_group->lock);
3151                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3152                 spin_unlock(&block_group->lock);
3153                 return 0;
3154         }
3155
3156 again:
3157         inode = lookup_free_space_inode(root, block_group, path);
3158         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3159                 ret = PTR_ERR(inode);
3160                 btrfs_release_path(path);
3161                 goto out;
3162         }
3163
3164         if (IS_ERR(inode)) {
3165                 BUG_ON(retries);
3166                 retries++;
3167
3168                 if (block_group->ro)
3169                         goto out_free;
3170
3171                 ret = create_free_space_inode(root, trans, block_group, path);
3172                 if (ret)
3173                         goto out_free;
3174                 goto again;
3175         }
3176
3177         /* We've already setup this transaction, go ahead and exit */
3178         if (block_group->cache_generation == trans->transid &&
3179             i_size_read(inode)) {
3180                 dcs = BTRFS_DC_SETUP;
3181                 goto out_put;
3182         }
3183
3184         /*
3185          * We want to set the generation to 0, that way if anything goes wrong
3186          * from here on out we know not to trust this cache when we load up next
3187          * time.
3188          */
3189         BTRFS_I(inode)->generation = 0;
3190         ret = btrfs_update_inode(trans, root, inode);
3191         WARN_ON(ret);
3192
3193         if (i_size_read(inode) > 0) {
3194                 ret = btrfs_check_trunc_cache_free_space(root,
3195                                         &root->fs_info->global_block_rsv);
3196                 if (ret)
3197                         goto out_put;
3198
3199                 ret = btrfs_truncate_free_space_cache(root, trans, path,
3200                                                       inode);
3201                 if (ret)
3202                         goto out_put;
3203         }
3204
3205         spin_lock(&block_group->lock);
3206         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3207             !btrfs_test_opt(root, SPACE_CACHE)) {
3208                 /*
3209                  * don't bother trying to write stuff out _if_
3210                  * a) we're not cached,
3211                  * b) we're with nospace_cache mount option.
3212                  */
3213                 dcs = BTRFS_DC_WRITTEN;
3214                 spin_unlock(&block_group->lock);
3215                 goto out_put;
3216         }
3217         spin_unlock(&block_group->lock);
3218
3219         /*
3220          * Try to preallocate enough space based on how big the block group is.
3221          * Keep in mind this has to include any pinned space which could end up
3222          * taking up quite a bit since it's not folded into the other space
3223          * cache.
3224          */
3225         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3226         if (!num_pages)
3227                 num_pages = 1;
3228
3229         num_pages *= 16;
3230         num_pages *= PAGE_CACHE_SIZE;
3231
3232         ret = btrfs_check_data_free_space(inode, num_pages);
3233         if (ret)
3234                 goto out_put;
3235
3236         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3237                                               num_pages, num_pages,
3238                                               &alloc_hint);
3239         if (!ret)
3240                 dcs = BTRFS_DC_SETUP;
3241         btrfs_free_reserved_data_space(inode, num_pages);
3242
3243 out_put:
3244         iput(inode);
3245 out_free:
3246         btrfs_release_path(path);
3247 out:
3248         spin_lock(&block_group->lock);
3249         if (!ret && dcs == BTRFS_DC_SETUP)
3250                 block_group->cache_generation = trans->transid;
3251         block_group->disk_cache_state = dcs;
3252         spin_unlock(&block_group->lock);
3253
3254         return ret;
3255 }
3256
3257 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3258                                    struct btrfs_root *root)
3259 {
3260         struct btrfs_block_group_cache *cache;
3261         int err = 0;
3262         struct btrfs_path *path;
3263         u64 last = 0;
3264
3265         path = btrfs_alloc_path();
3266         if (!path)
3267                 return -ENOMEM;
3268
3269 again:
3270         while (1) {
3271                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3272                 while (cache) {
3273                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3274                                 break;
3275                         cache = next_block_group(root, cache);
3276                 }
3277                 if (!cache) {
3278                         if (last == 0)
3279                                 break;
3280                         last = 0;
3281                         continue;
3282                 }
3283                 err = cache_save_setup(cache, trans, path);
3284                 last = cache->key.objectid + cache->key.offset;
3285                 btrfs_put_block_group(cache);
3286         }
3287
3288         while (1) {
3289                 if (last == 0) {
3290                         err = btrfs_run_delayed_refs(trans, root,
3291                                                      (unsigned long)-1);
3292                         if (err) /* File system offline */
3293                                 goto out;
3294                 }
3295
3296                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3297                 while (cache) {
3298                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3299                                 btrfs_put_block_group(cache);
3300                                 goto again;
3301                         }
3302
3303                         if (cache->dirty)
3304                                 break;
3305                         cache = next_block_group(root, cache);
3306                 }
3307                 if (!cache) {
3308                         if (last == 0)
3309                                 break;
3310                         last = 0;
3311                         continue;
3312                 }
3313
3314                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3315                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3316                 cache->dirty = 0;
3317                 last = cache->key.objectid + cache->key.offset;
3318
3319                 err = write_one_cache_group(trans, root, path, cache);
3320                 if (err) /* File system offline */
3321                         goto out;
3322
3323                 btrfs_put_block_group(cache);
3324         }
3325
3326         while (1) {
3327                 /*
3328                  * I don't think this is needed since we're just marking our
3329                  * preallocated extent as written, but just in case it can't
3330                  * hurt.
3331                  */
3332                 if (last == 0) {
3333                         err = btrfs_run_delayed_refs(trans, root,
3334                                                      (unsigned long)-1);
3335                         if (err) /* File system offline */
3336                                 goto out;
3337                 }
3338
3339                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3340                 while (cache) {
3341                         /*
3342                          * Really this shouldn't happen, but it could if we
3343                          * couldn't write the entire preallocated extent and
3344                          * splitting the extent resulted in a new block.
3345                          */
3346                         if (cache->dirty) {
3347                                 btrfs_put_block_group(cache);
3348                                 goto again;
3349                         }
3350                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3351                                 break;
3352                         cache = next_block_group(root, cache);
3353                 }
3354                 if (!cache) {
3355                         if (last == 0)
3356                                 break;
3357                         last = 0;
3358                         continue;
3359                 }
3360
3361                 err = btrfs_write_out_cache(root, trans, cache, path);
3362
3363                 /*
3364                  * If we didn't have an error then the cache state is still
3365                  * NEED_WRITE, so we can set it to WRITTEN.
3366                  */
3367                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3368                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3369                 last = cache->key.objectid + cache->key.offset;
3370                 btrfs_put_block_group(cache);
3371         }
3372 out:
3373
3374         btrfs_free_path(path);
3375         return err;
3376 }
3377
3378 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3379 {
3380         struct btrfs_block_group_cache *block_group;
3381         int readonly = 0;
3382
3383         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3384         if (!block_group || block_group->ro)
3385                 readonly = 1;
3386         if (block_group)
3387                 btrfs_put_block_group(block_group);
3388         return readonly;
3389 }
3390
3391 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3392                              u64 total_bytes, u64 bytes_used,
3393                              struct btrfs_space_info **space_info)
3394 {
3395         struct btrfs_space_info *found;
3396         int i;
3397         int factor;
3398         int ret;
3399
3400         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3401                      BTRFS_BLOCK_GROUP_RAID10))
3402                 factor = 2;
3403         else
3404                 factor = 1;
3405
3406         found = __find_space_info(info, flags);
3407         if (found) {
3408                 spin_lock(&found->lock);
3409                 found->total_bytes += total_bytes;
3410                 found->disk_total += total_bytes * factor;
3411                 found->bytes_used += bytes_used;
3412                 found->disk_used += bytes_used * factor;
3413                 found->full = 0;
3414                 spin_unlock(&found->lock);
3415                 *space_info = found;
3416                 return 0;
3417         }
3418         found = kzalloc(sizeof(*found), GFP_NOFS);
3419         if (!found)
3420                 return -ENOMEM;
3421
3422         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3423         if (ret) {
3424                 kfree(found);
3425                 return ret;
3426         }
3427
3428         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3429                 INIT_LIST_HEAD(&found->block_groups[i]);
3430         init_rwsem(&found->groups_sem);
3431         spin_lock_init(&found->lock);
3432         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3433         found->total_bytes = total_bytes;
3434         found->disk_total = total_bytes * factor;
3435         found->bytes_used = bytes_used;
3436         found->disk_used = bytes_used * factor;
3437         found->bytes_pinned = 0;
3438         found->bytes_reserved = 0;
3439         found->bytes_readonly = 0;
3440         found->bytes_may_use = 0;
3441         found->full = 0;
3442         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3443         found->chunk_alloc = 0;
3444         found->flush = 0;
3445         init_waitqueue_head(&found->wait);
3446         *space_info = found;
3447         list_add_rcu(&found->list, &info->space_info);
3448         if (flags & BTRFS_BLOCK_GROUP_DATA)
3449                 info->data_sinfo = found;
3450         return 0;
3451 }
3452
3453 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3454 {
3455         u64 extra_flags = chunk_to_extended(flags) &
3456                                 BTRFS_EXTENDED_PROFILE_MASK;
3457
3458         write_seqlock(&fs_info->profiles_lock);
3459         if (flags & BTRFS_BLOCK_GROUP_DATA)
3460                 fs_info->avail_data_alloc_bits |= extra_flags;
3461         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3462                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3463         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3464                 fs_info->avail_system_alloc_bits |= extra_flags;
3465         write_sequnlock(&fs_info->profiles_lock);
3466 }
3467
3468 /*
3469  * returns target flags in extended format or 0 if restripe for this
3470  * chunk_type is not in progress
3471  *
3472  * should be called with either volume_mutex or balance_lock held
3473  */
3474 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3475 {
3476         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3477         u64 target = 0;
3478
3479         if (!bctl)
3480                 return 0;
3481
3482         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3483             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3484                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3485         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3486                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3487                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3488         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3489                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3490                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3491         }
3492
3493         return target;
3494 }
3495
3496 /*
3497  * @flags: available profiles in extended format (see ctree.h)
3498  *
3499  * Returns reduced profile in chunk format.  If profile changing is in
3500  * progress (either running or paused) picks the target profile (if it's
3501  * already available), otherwise falls back to plain reducing.
3502  */
3503 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3504 {
3505         /*
3506          * we add in the count of missing devices because we want
3507          * to make sure that any RAID levels on a degraded FS
3508          * continue to be honored.
3509          */
3510         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3511                 root->fs_info->fs_devices->missing_devices;
3512         u64 target;
3513         u64 tmp;
3514
3515         /*
3516          * see if restripe for this chunk_type is in progress, if so
3517          * try to reduce to the target profile
3518          */
3519         spin_lock(&root->fs_info->balance_lock);
3520         target = get_restripe_target(root->fs_info, flags);
3521         if (target) {
3522                 /* pick target profile only if it's already available */
3523                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3524                         spin_unlock(&root->fs_info->balance_lock);
3525                         return extended_to_chunk(target);
3526                 }
3527         }
3528         spin_unlock(&root->fs_info->balance_lock);
3529
3530         /* First, mask out the RAID levels which aren't possible */
3531         if (num_devices == 1)
3532                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3533                            BTRFS_BLOCK_GROUP_RAID5);
3534         if (num_devices < 3)
3535                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3536         if (num_devices < 4)
3537                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3538
3539         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3540                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3541                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3542         flags &= ~tmp;
3543
3544         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3545                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3546         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3547                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3548         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3549                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3550         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3551                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3552         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3553                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3554
3555         return extended_to_chunk(flags | tmp);
3556 }
3557
3558 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3559 {
3560         unsigned seq;
3561
3562         do {
3563                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3564
3565                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3566                         flags |= root->fs_info->avail_data_alloc_bits;
3567                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3568                         flags |= root->fs_info->avail_system_alloc_bits;
3569                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3570                         flags |= root->fs_info->avail_metadata_alloc_bits;
3571         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3572
3573         return btrfs_reduce_alloc_profile(root, flags);
3574 }
3575
3576 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3577 {
3578         u64 flags;
3579         u64 ret;
3580
3581         if (data)
3582                 flags = BTRFS_BLOCK_GROUP_DATA;
3583         else if (root == root->fs_info->chunk_root)
3584                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3585         else
3586                 flags = BTRFS_BLOCK_GROUP_METADATA;
3587
3588         ret = get_alloc_profile(root, flags);
3589         return ret;
3590 }
3591
3592 /*
3593  * This will check the space that the inode allocates from to make sure we have
3594  * enough space for bytes.
3595  */
3596 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3597 {
3598         struct btrfs_space_info *data_sinfo;
3599         struct btrfs_root *root = BTRFS_I(inode)->root;
3600         struct btrfs_fs_info *fs_info = root->fs_info;
3601         u64 used;
3602         int ret = 0, committed = 0, alloc_chunk = 1;
3603
3604         /* make sure bytes are sectorsize aligned */
3605         bytes = ALIGN(bytes, root->sectorsize);
3606
3607         if (root == root->fs_info->tree_root ||
3608             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3609                 alloc_chunk = 0;
3610                 committed = 1;
3611         }
3612
3613         data_sinfo = fs_info->data_sinfo;
3614         if (!data_sinfo)
3615                 goto alloc;
3616
3617 again:
3618         /* make sure we have enough space to handle the data first */
3619         spin_lock(&data_sinfo->lock);
3620         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3621                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3622                 data_sinfo->bytes_may_use;
3623
3624         if (used + bytes > data_sinfo->total_bytes) {
3625                 struct btrfs_trans_handle *trans;
3626
3627                 /*
3628                  * if we don't have enough free bytes in this space then we need
3629                  * to alloc a new chunk.
3630                  */
3631                 if (!data_sinfo->full && alloc_chunk) {
3632                         u64 alloc_target;
3633
3634                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3635                         spin_unlock(&data_sinfo->lock);
3636 alloc:
3637                         alloc_target = btrfs_get_alloc_profile(root, 1);
3638                         trans = btrfs_join_transaction(root);
3639                         if (IS_ERR(trans))
3640                                 return PTR_ERR(trans);
3641
3642                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3643                                              alloc_target,
3644                                              CHUNK_ALLOC_NO_FORCE);
3645                         btrfs_end_transaction(trans, root);
3646                         if (ret < 0) {
3647                                 if (ret != -ENOSPC)
3648                                         return ret;
3649                                 else
3650                                         goto commit_trans;
3651                         }
3652
3653                         if (!data_sinfo)
3654                                 data_sinfo = fs_info->data_sinfo;
3655
3656                         goto again;
3657                 }
3658
3659                 /*
3660                  * If we don't have enough pinned space to deal with this
3661                  * allocation don't bother committing the transaction.
3662                  */
3663                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3664                                            bytes) < 0)
3665                         committed = 1;
3666                 spin_unlock(&data_sinfo->lock);
3667
3668                 /* commit the current transaction and try again */
3669 commit_trans:
3670                 if (!committed &&
3671                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3672                         committed = 1;
3673
3674                         trans = btrfs_join_transaction(root);
3675                         if (IS_ERR(trans))
3676                                 return PTR_ERR(trans);
3677                         ret = btrfs_commit_transaction(trans, root);
3678                         if (ret)
3679                                 return ret;
3680                         goto again;
3681                 }
3682
3683                 return -ENOSPC;
3684         }
3685         data_sinfo->bytes_may_use += bytes;
3686         trace_btrfs_space_reservation(root->fs_info, "space_info",
3687                                       data_sinfo->flags, bytes, 1);
3688         spin_unlock(&data_sinfo->lock);
3689
3690         return 0;
3691 }
3692
3693 /*
3694  * Called if we need to clear a data reservation for this inode.
3695  */
3696 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3697 {
3698         struct btrfs_root *root = BTRFS_I(inode)->root;
3699         struct btrfs_space_info *data_sinfo;
3700
3701         /* make sure bytes are sectorsize aligned */
3702         bytes = ALIGN(bytes, root->sectorsize);
3703
3704         data_sinfo = root->fs_info->data_sinfo;
3705         spin_lock(&data_sinfo->lock);
3706         WARN_ON(data_sinfo->bytes_may_use < bytes);
3707         data_sinfo->bytes_may_use -= bytes;
3708         trace_btrfs_space_reservation(root->fs_info, "space_info",
3709                                       data_sinfo->flags, bytes, 0);
3710         spin_unlock(&data_sinfo->lock);
3711 }
3712
3713 static void force_metadata_allocation(struct btrfs_fs_info *info)
3714 {
3715         struct list_head *head = &info->space_info;
3716         struct btrfs_space_info *found;
3717
3718         rcu_read_lock();
3719         list_for_each_entry_rcu(found, head, list) {
3720                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3721                         found->force_alloc = CHUNK_ALLOC_FORCE;
3722         }
3723         rcu_read_unlock();
3724 }
3725
3726 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3727 {
3728         return (global->size << 1);
3729 }
3730
3731 static int should_alloc_chunk(struct btrfs_root *root,
3732                               struct btrfs_space_info *sinfo, int force)
3733 {
3734         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3735         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3736         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3737         u64 thresh;
3738
3739         if (force == CHUNK_ALLOC_FORCE)
3740                 return 1;
3741
3742         /*
3743          * We need to take into account the global rsv because for all intents
3744          * and purposes it's used space.  Don't worry about locking the
3745          * global_rsv, it doesn't change except when the transaction commits.
3746          */
3747         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3748                 num_allocated += calc_global_rsv_need_space(global_rsv);
3749
3750         /*
3751          * in limited mode, we want to have some free space up to
3752          * about 1% of the FS size.
3753          */
3754         if (force == CHUNK_ALLOC_LIMITED) {
3755                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3756                 thresh = max_t(u64, 64 * 1024 * 1024,
3757                                div_factor_fine(thresh, 1));
3758
3759                 if (num_bytes - num_allocated < thresh)
3760                         return 1;
3761         }
3762
3763         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3764                 return 0;
3765         return 1;
3766 }
3767
3768 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3769 {
3770         u64 num_dev;
3771
3772         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3773                     BTRFS_BLOCK_GROUP_RAID0 |
3774                     BTRFS_BLOCK_GROUP_RAID5 |
3775                     BTRFS_BLOCK_GROUP_RAID6))
3776                 num_dev = root->fs_info->fs_devices->rw_devices;
3777         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3778                 num_dev = 2;
3779         else
3780                 num_dev = 1;    /* DUP or single */
3781
3782         /* metadata for updaing devices and chunk tree */
3783         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3784 }
3785
3786 static void check_system_chunk(struct btrfs_trans_handle *trans,
3787                                struct btrfs_root *root, u64 type)
3788 {
3789         struct btrfs_space_info *info;
3790         u64 left;
3791         u64 thresh;
3792
3793         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3794         spin_lock(&info->lock);
3795         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3796                 info->bytes_reserved - info->bytes_readonly;
3797         spin_unlock(&info->lock);
3798
3799         thresh = get_system_chunk_thresh(root, type);
3800         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3801                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3802                         left, thresh, type);
3803                 dump_space_info(info, 0, 0);
3804         }
3805
3806         if (left < thresh) {
3807                 u64 flags;
3808
3809                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3810                 btrfs_alloc_chunk(trans, root, flags);
3811         }
3812 }
3813
3814 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3815                           struct btrfs_root *extent_root, u64 flags, int force)
3816 {
3817         struct btrfs_space_info *space_info;
3818         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3819         int wait_for_alloc = 0;
3820         int ret = 0;
3821
3822         /* Don't re-enter if we're already allocating a chunk */
3823         if (trans->allocating_chunk)
3824                 return -ENOSPC;
3825
3826         space_info = __find_space_info(extent_root->fs_info, flags);
3827         if (!space_info) {
3828                 ret = update_space_info(extent_root->fs_info, flags,
3829                                         0, 0, &space_info);
3830                 BUG_ON(ret); /* -ENOMEM */
3831         }
3832         BUG_ON(!space_info); /* Logic error */
3833
3834 again:
3835         spin_lock(&space_info->lock);
3836         if (force < space_info->force_alloc)
3837                 force = space_info->force_alloc;
3838         if (space_info->full) {
3839                 if (should_alloc_chunk(extent_root, space_info, force))
3840                         ret = -ENOSPC;
3841                 else
3842                         ret = 0;
3843                 spin_unlock(&space_info->lock);
3844                 return ret;
3845         }
3846
3847         if (!should_alloc_chunk(extent_root, space_info, force)) {
3848                 spin_unlock(&space_info->lock);
3849                 return 0;
3850         } else if (space_info->chunk_alloc) {
3851                 wait_for_alloc = 1;
3852         } else {
3853                 space_info->chunk_alloc = 1;
3854         }
3855
3856         spin_unlock(&space_info->lock);
3857
3858         mutex_lock(&fs_info->chunk_mutex);
3859
3860         /*
3861          * The chunk_mutex is held throughout the entirety of a chunk
3862          * allocation, so once we've acquired the chunk_mutex we know that the
3863          * other guy is done and we need to recheck and see if we should
3864          * allocate.
3865          */
3866         if (wait_for_alloc) {
3867                 mutex_unlock(&fs_info->chunk_mutex);
3868                 wait_for_alloc = 0;
3869                 goto again;
3870         }
3871
3872         trans->allocating_chunk = true;
3873
3874         /*
3875          * If we have mixed data/metadata chunks we want to make sure we keep
3876          * allocating mixed chunks instead of individual chunks.
3877          */
3878         if (btrfs_mixed_space_info(space_info))
3879                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3880
3881         /*
3882          * if we're doing a data chunk, go ahead and make sure that
3883          * we keep a reasonable number of metadata chunks allocated in the
3884          * FS as well.
3885          */
3886         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3887                 fs_info->data_chunk_allocations++;
3888                 if (!(fs_info->data_chunk_allocations %
3889                       fs_info->metadata_ratio))
3890                         force_metadata_allocation(fs_info);
3891         }
3892
3893         /*
3894          * Check if we have enough space in SYSTEM chunk because we may need
3895          * to update devices.
3896          */
3897         check_system_chunk(trans, extent_root, flags);
3898
3899         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3900         trans->allocating_chunk = false;
3901
3902         spin_lock(&space_info->lock);
3903         if (ret < 0 && ret != -ENOSPC)
3904                 goto out;
3905         if (ret)
3906                 space_info->full = 1;
3907         else
3908                 ret = 1;
3909
3910         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3911 out:
3912         space_info->chunk_alloc = 0;
3913         spin_unlock(&space_info->lock);
3914         mutex_unlock(&fs_info->chunk_mutex);
3915         return ret;
3916 }
3917
3918 static int can_overcommit(struct btrfs_root *root,
3919                           struct btrfs_space_info *space_info, u64 bytes,
3920                           enum btrfs_reserve_flush_enum flush)
3921 {
3922         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3923         u64 profile = btrfs_get_alloc_profile(root, 0);
3924         u64 space_size;
3925         u64 avail;
3926         u64 used;
3927         u64 to_add;
3928
3929         used = space_info->bytes_used + space_info->bytes_reserved +
3930                 space_info->bytes_pinned + space_info->bytes_readonly;
3931
3932         /*
3933          * We only want to allow over committing if we have lots of actual space
3934          * free, but if we don't have enough space to handle the global reserve
3935          * space then we could end up having a real enospc problem when trying
3936          * to allocate a chunk or some other such important allocation.
3937          */
3938         spin_lock(&global_rsv->lock);
3939         space_size = calc_global_rsv_need_space(global_rsv);
3940         spin_unlock(&global_rsv->lock);
3941         if (used + space_size >= space_info->total_bytes)
3942                 return 0;
3943
3944         used += space_info->bytes_may_use;
3945
3946         spin_lock(&root->fs_info->free_chunk_lock);
3947         avail = root->fs_info->free_chunk_space;
3948         spin_unlock(&root->fs_info->free_chunk_lock);
3949
3950         /*
3951          * If we have dup, raid1 or raid10 then only half of the free
3952          * space is actually useable.  For raid56, the space info used
3953          * doesn't include the parity drive, so we don't have to
3954          * change the math
3955          */
3956         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3957                        BTRFS_BLOCK_GROUP_RAID1 |
3958                        BTRFS_BLOCK_GROUP_RAID10))
3959                 avail >>= 1;
3960
3961         to_add = space_info->total_bytes;
3962
3963         /*
3964          * If we aren't flushing all things, let us overcommit up to
3965          * 1/2th of the space. If we can flush, don't let us overcommit
3966          * too much, let it overcommit up to 1/8 of the space.
3967          */
3968         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3969                 to_add >>= 3;
3970         else
3971                 to_add >>= 1;
3972
3973         /*
3974          * Limit the overcommit to the amount of free space we could possibly
3975          * allocate for chunks.
3976          */
3977         to_add = min(avail, to_add);
3978
3979         if (used + bytes < space_info->total_bytes + to_add)
3980                 return 1;
3981         return 0;
3982 }
3983
3984 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3985                                          unsigned long nr_pages)
3986 {
3987         struct super_block *sb = root->fs_info->sb;
3988
3989         if (down_read_trylock(&sb->s_umount)) {
3990                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3991                 up_read(&sb->s_umount);
3992         } else {
3993                 /*
3994                  * We needn't worry the filesystem going from r/w to r/o though
3995                  * we don't acquire ->s_umount mutex, because the filesystem
3996                  * should guarantee the delalloc inodes list be empty after
3997                  * the filesystem is readonly(all dirty pages are written to
3998                  * the disk).
3999                  */
4000                 btrfs_start_all_delalloc_inodes(root->fs_info, 0);
4001                 if (!current->journal_info)
4002                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
4003         }
4004 }
4005
4006 /*
4007  * shrink metadata reservation for delalloc
4008  */
4009 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4010                             bool wait_ordered)
4011 {
4012         struct btrfs_block_rsv *block_rsv;
4013         struct btrfs_space_info *space_info;
4014         struct btrfs_trans_handle *trans;
4015         u64 delalloc_bytes;
4016         u64 max_reclaim;
4017         long time_left;
4018         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
4019         int loops = 0;
4020         enum btrfs_reserve_flush_enum flush;
4021
4022         trans = (struct btrfs_trans_handle *)current->journal_info;
4023         block_rsv = &root->fs_info->delalloc_block_rsv;
4024         space_info = block_rsv->space_info;
4025
4026         smp_mb();
4027         delalloc_bytes = percpu_counter_sum_positive(
4028                                                 &root->fs_info->delalloc_bytes);
4029         if (delalloc_bytes == 0) {
4030                 if (trans)
4031                         return;
4032                 btrfs_wait_all_ordered_extents(root->fs_info, 0);
4033                 return;
4034         }
4035
4036         while (delalloc_bytes && loops < 3) {
4037                 max_reclaim = min(delalloc_bytes, to_reclaim);
4038                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4039                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4040                 /*
4041                  * We need to wait for the async pages to actually start before
4042                  * we do anything.
4043                  */
4044                 wait_event(root->fs_info->async_submit_wait,
4045                            !atomic_read(&root->fs_info->async_delalloc_pages));
4046
4047                 if (!trans)
4048                         flush = BTRFS_RESERVE_FLUSH_ALL;
4049                 else
4050                         flush = BTRFS_RESERVE_NO_FLUSH;
4051                 spin_lock(&space_info->lock);
4052                 if (can_overcommit(root, space_info, orig, flush)) {
4053                         spin_unlock(&space_info->lock);
4054                         break;
4055                 }
4056                 spin_unlock(&space_info->lock);
4057
4058                 loops++;
4059                 if (wait_ordered && !trans) {
4060                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
4061                 } else {
4062                         time_left = schedule_timeout_killable(1);
4063                         if (time_left)
4064                                 break;
4065                 }
4066                 smp_mb();
4067                 delalloc_bytes = percpu_counter_sum_positive(
4068                                                 &root->fs_info->delalloc_bytes);
4069         }
4070 }
4071
4072 /**
4073  * maybe_commit_transaction - possibly commit the transaction if its ok to
4074  * @root - the root we're allocating for
4075  * @bytes - the number of bytes we want to reserve
4076  * @force - force the commit
4077  *
4078  * This will check to make sure that committing the transaction will actually
4079  * get us somewhere and then commit the transaction if it does.  Otherwise it
4080  * will return -ENOSPC.
4081  */
4082 static int may_commit_transaction(struct btrfs_root *root,
4083                                   struct btrfs_space_info *space_info,
4084                                   u64 bytes, int force)
4085 {
4086         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4087         struct btrfs_trans_handle *trans;
4088
4089         trans = (struct btrfs_trans_handle *)current->journal_info;
4090         if (trans)
4091                 return -EAGAIN;
4092
4093         if (force)
4094                 goto commit;
4095
4096         /* See if there is enough pinned space to make this reservation */
4097         spin_lock(&space_info->lock);
4098         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4099                                    bytes) >= 0) {
4100                 spin_unlock(&space_info->lock);
4101                 goto commit;
4102         }
4103         spin_unlock(&space_info->lock);
4104
4105         /*
4106          * See if there is some space in the delayed insertion reservation for
4107          * this reservation.
4108          */
4109         if (space_info != delayed_rsv->space_info)
4110                 return -ENOSPC;
4111
4112         spin_lock(&space_info->lock);
4113         spin_lock(&delayed_rsv->lock);
4114         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4115                                    bytes - delayed_rsv->size) >= 0) {
4116                 spin_unlock(&delayed_rsv->lock);
4117                 spin_unlock(&space_info->lock);
4118                 return -ENOSPC;
4119         }
4120         spin_unlock(&delayed_rsv->lock);
4121         spin_unlock(&space_info->lock);
4122
4123 commit:
4124         trans = btrfs_join_transaction(root);
4125         if (IS_ERR(trans))
4126                 return -ENOSPC;
4127
4128         return btrfs_commit_transaction(trans, root);
4129 }
4130
4131 enum flush_state {
4132         FLUSH_DELAYED_ITEMS_NR  =       1,
4133         FLUSH_DELAYED_ITEMS     =       2,
4134         FLUSH_DELALLOC          =       3,
4135         FLUSH_DELALLOC_WAIT     =       4,
4136         ALLOC_CHUNK             =       5,
4137         COMMIT_TRANS            =       6,
4138 };
4139
4140 static int flush_space(struct btrfs_root *root,
4141                        struct btrfs_space_info *space_info, u64 num_bytes,
4142                        u64 orig_bytes, int state)
4143 {
4144         struct btrfs_trans_handle *trans;
4145         int nr;
4146         int ret = 0;
4147
4148         switch (state) {
4149         case FLUSH_DELAYED_ITEMS_NR:
4150         case FLUSH_DELAYED_ITEMS:
4151                 if (state == FLUSH_DELAYED_ITEMS_NR) {
4152                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
4153
4154                         nr = (int)div64_u64(num_bytes, bytes);
4155                         if (!nr)
4156                                 nr = 1;
4157                         nr *= 2;
4158                 } else {
4159                         nr = -1;
4160                 }
4161                 trans = btrfs_join_transaction(root);
4162                 if (IS_ERR(trans)) {
4163                         ret = PTR_ERR(trans);
4164                         break;
4165                 }
4166                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4167                 btrfs_end_transaction(trans, root);
4168                 break;
4169         case FLUSH_DELALLOC:
4170         case FLUSH_DELALLOC_WAIT:
4171                 shrink_delalloc(root, num_bytes, orig_bytes,
4172                                 state == FLUSH_DELALLOC_WAIT);
4173                 break;
4174         case ALLOC_CHUNK:
4175                 trans = btrfs_join_transaction(root);
4176                 if (IS_ERR(trans)) {
4177                         ret = PTR_ERR(trans);
4178                         break;
4179                 }
4180                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4181                                      btrfs_get_alloc_profile(root, 0),
4182                                      CHUNK_ALLOC_NO_FORCE);
4183                 btrfs_end_transaction(trans, root);
4184                 if (ret == -ENOSPC)
4185                         ret = 0;
4186                 break;
4187         case COMMIT_TRANS:
4188                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4189                 break;
4190         default:
4191                 ret = -ENOSPC;
4192                 break;
4193         }
4194
4195         return ret;
4196 }
4197 /**
4198  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4199  * @root - the root we're allocating for
4200  * @block_rsv - the block_rsv we're allocating for
4201  * @orig_bytes - the number of bytes we want
4202  * @flush - whether or not we can flush to make our reservation
4203  *
4204  * This will reserve orgi_bytes number of bytes from the space info associated
4205  * with the block_rsv.  If there is not enough space it will make an attempt to
4206  * flush out space to make room.  It will do this by flushing delalloc if
4207  * possible or committing the transaction.  If flush is 0 then no attempts to
4208  * regain reservations will be made and this will fail if there is not enough
4209  * space already.
4210  */
4211 static int reserve_metadata_bytes(struct btrfs_root *root,
4212                                   struct btrfs_block_rsv *block_rsv,
4213                                   u64 orig_bytes,
4214                                   enum btrfs_reserve_flush_enum flush)
4215 {
4216         struct btrfs_space_info *space_info = block_rsv->space_info;
4217         u64 used;
4218         u64 num_bytes = orig_bytes;
4219         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4220         int ret = 0;
4221         bool flushing = false;
4222
4223 again:
4224         ret = 0;
4225         spin_lock(&space_info->lock);
4226         /*
4227          * We only want to wait if somebody other than us is flushing and we
4228          * are actually allowed to flush all things.
4229          */
4230         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4231                space_info->flush) {
4232                 spin_unlock(&space_info->lock);
4233                 /*
4234                  * If we have a trans handle we can't wait because the flusher
4235                  * may have to commit the transaction, which would mean we would
4236                  * deadlock since we are waiting for the flusher to finish, but
4237                  * hold the current transaction open.
4238                  */
4239                 if (current->journal_info)
4240                         return -EAGAIN;
4241                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4242                 /* Must have been killed, return */
4243                 if (ret)
4244                         return -EINTR;
4245
4246                 spin_lock(&space_info->lock);
4247         }
4248
4249         ret = -ENOSPC;
4250         used = space_info->bytes_used + space_info->bytes_reserved +
4251                 space_info->bytes_pinned + space_info->bytes_readonly +
4252                 space_info->bytes_may_use;
4253
4254         /*
4255          * The idea here is that we've not already over-reserved the block group
4256          * then we can go ahead and save our reservation first and then start
4257          * flushing if we need to.  Otherwise if we've already overcommitted
4258          * lets start flushing stuff first and then come back and try to make
4259          * our reservation.
4260          */
4261         if (used <= space_info->total_bytes) {
4262                 if (used + orig_bytes <= space_info->total_bytes) {
4263                         space_info->bytes_may_use += orig_bytes;
4264                         trace_btrfs_space_reservation(root->fs_info,
4265                                 "space_info", space_info->flags, orig_bytes, 1);
4266                         ret = 0;
4267                 } else {
4268                         /*
4269                          * Ok set num_bytes to orig_bytes since we aren't
4270                          * overocmmitted, this way we only try and reclaim what
4271                          * we need.
4272                          */
4273                         num_bytes = orig_bytes;
4274                 }
4275         } else {
4276                 /*
4277                  * Ok we're over committed, set num_bytes to the overcommitted
4278                  * amount plus the amount of bytes that we need for this
4279                  * reservation.
4280                  */
4281                 num_bytes = used - space_info->total_bytes +
4282                         (orig_bytes * 2);
4283         }
4284
4285         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4286                 space_info->bytes_may_use += orig_bytes;
4287                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4288                                               space_info->flags, orig_bytes,
4289                                               1);
4290                 ret = 0;
4291         }
4292
4293         /*
4294          * Couldn't make our reservation, save our place so while we're trying
4295          * to reclaim space we can actually use it instead of somebody else
4296          * stealing it from us.
4297          *
4298          * We make the other tasks wait for the flush only when we can flush
4299          * all things.
4300          */
4301         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4302                 flushing = true;
4303                 space_info->flush = 1;
4304         }
4305
4306         spin_unlock(&space_info->lock);
4307
4308         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4309                 goto out;
4310
4311         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4312                           flush_state);
4313         flush_state++;
4314
4315         /*
4316          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4317          * would happen. So skip delalloc flush.
4318          */
4319         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4320             (flush_state == FLUSH_DELALLOC ||
4321              flush_state == FLUSH_DELALLOC_WAIT))
4322                 flush_state = ALLOC_CHUNK;
4323
4324         if (!ret)
4325                 goto again;
4326         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4327                  flush_state < COMMIT_TRANS)
4328                 goto again;
4329         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4330                  flush_state <= COMMIT_TRANS)
4331                 goto again;
4332
4333 out:
4334         if (ret == -ENOSPC &&
4335             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4336                 struct btrfs_block_rsv *global_rsv =
4337                         &root->fs_info->global_block_rsv;
4338
4339                 if (block_rsv != global_rsv &&
4340                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4341                         ret = 0;
4342         }
4343         if (flushing) {
4344                 spin_lock(&space_info->lock);
4345                 space_info->flush = 0;
4346                 wake_up_all(&space_info->wait);
4347                 spin_unlock(&space_info->lock);
4348         }
4349         return ret;
4350 }
4351
4352 static struct btrfs_block_rsv *get_block_rsv(
4353                                         const struct btrfs_trans_handle *trans,
4354                                         const struct btrfs_root *root)
4355 {
4356         struct btrfs_block_rsv *block_rsv = NULL;
4357
4358         if (root->ref_cows)
4359                 block_rsv = trans->block_rsv;
4360
4361         if (root == root->fs_info->csum_root && trans->adding_csums)
4362                 block_rsv = trans->block_rsv;
4363
4364         if (!block_rsv)
4365                 block_rsv = root->block_rsv;
4366
4367         if (!block_rsv)
4368                 block_rsv = &root->fs_info->empty_block_rsv;
4369
4370         return block_rsv;
4371 }
4372
4373 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4374                                u64 num_bytes)
4375 {
4376         int ret = -ENOSPC;
4377         spin_lock(&block_rsv->lock);
4378         if (block_rsv->reserved >= num_bytes) {
4379                 block_rsv->reserved -= num_bytes;
4380                 if (block_rsv->reserved < block_rsv->size)
4381                         block_rsv->full = 0;
4382                 ret = 0;
4383         }
4384         spin_unlock(&block_rsv->lock);
4385         return ret;
4386 }
4387
4388 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4389                                 u64 num_bytes, int update_size)
4390 {
4391         spin_lock(&block_rsv->lock);
4392         block_rsv->reserved += num_bytes;
4393         if (update_size)
4394                 block_rsv->size += num_bytes;
4395         else if (block_rsv->reserved >= block_rsv->size)
4396                 block_rsv->full = 1;
4397         spin_unlock(&block_rsv->lock);
4398 }
4399
4400 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4401                              struct btrfs_block_rsv *dest, u64 num_bytes,
4402                              int min_factor)
4403 {
4404         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4405         u64 min_bytes;
4406
4407         if (global_rsv->space_info != dest->space_info)
4408                 return -ENOSPC;
4409
4410         spin_lock(&global_rsv->lock);
4411         min_bytes = div_factor(global_rsv->size, min_factor);
4412         if (global_rsv->reserved < min_bytes + num_bytes) {
4413                 spin_unlock(&global_rsv->lock);
4414                 return -ENOSPC;
4415         }
4416         global_rsv->reserved -= num_bytes;
4417         if (global_rsv->reserved < global_rsv->size)
4418                 global_rsv->full = 0;
4419         spin_unlock(&global_rsv->lock);
4420
4421         block_rsv_add_bytes(dest, num_bytes, 1);
4422         return 0;
4423 }
4424
4425 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4426                                     struct btrfs_block_rsv *block_rsv,
4427                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4428 {
4429         struct btrfs_space_info *space_info = block_rsv->space_info;
4430
4431         spin_lock(&block_rsv->lock);
4432         if (num_bytes == (u64)-1)
4433                 num_bytes = block_rsv->size;
4434         block_rsv->size -= num_bytes;
4435         if (block_rsv->reserved >= block_rsv->size) {
4436                 num_bytes = block_rsv->reserved - block_rsv->size;
4437                 block_rsv->reserved = block_rsv->size;
4438                 block_rsv->full = 1;
4439         } else {
4440                 num_bytes = 0;
4441         }
4442         spin_unlock(&block_rsv->lock);
4443
4444         if (num_bytes > 0) {
4445                 if (dest) {
4446                         spin_lock(&dest->lock);
4447                         if (!dest->full) {
4448                                 u64 bytes_to_add;
4449
4450                                 bytes_to_add = dest->size - dest->reserved;
4451                                 bytes_to_add = min(num_bytes, bytes_to_add);
4452                                 dest->reserved += bytes_to_add;
4453                                 if (dest->reserved >= dest->size)
4454                                         dest->full = 1;
4455                                 num_bytes -= bytes_to_add;
4456                         }
4457                         spin_unlock(&dest->lock);
4458                 }
4459                 if (num_bytes) {
4460                         spin_lock(&space_info->lock);
4461                         space_info->bytes_may_use -= num_bytes;
4462                         trace_btrfs_space_reservation(fs_info, "space_info",
4463                                         space_info->flags, num_bytes, 0);
4464                         space_info->reservation_progress++;
4465                         spin_unlock(&space_info->lock);
4466                 }
4467         }
4468 }
4469
4470 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4471                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4472 {
4473         int ret;
4474
4475         ret = block_rsv_use_bytes(src, num_bytes);
4476         if (ret)
4477                 return ret;
4478
4479         block_rsv_add_bytes(dst, num_bytes, 1);
4480         return 0;
4481 }
4482
4483 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4484 {
4485         memset(rsv, 0, sizeof(*rsv));
4486         spin_lock_init(&rsv->lock);
4487         rsv->type = type;
4488 }
4489
4490 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4491                                               unsigned short type)
4492 {
4493         struct btrfs_block_rsv *block_rsv;
4494         struct btrfs_fs_info *fs_info = root->fs_info;
4495
4496         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4497         if (!block_rsv)
4498                 return NULL;
4499
4500         btrfs_init_block_rsv(block_rsv, type);
4501         block_rsv->space_info = __find_space_info(fs_info,
4502                                                   BTRFS_BLOCK_GROUP_METADATA);
4503         return block_rsv;
4504 }
4505
4506 void btrfs_free_block_rsv(struct btrfs_root *root,
4507                           struct btrfs_block_rsv *rsv)
4508 {
4509         if (!rsv)
4510                 return;
4511         btrfs_block_rsv_release(root, rsv, (u64)-1);
4512         kfree(rsv);
4513 }
4514
4515 int btrfs_block_rsv_add(struct btrfs_root *root,
4516                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4517                         enum btrfs_reserve_flush_enum flush)
4518 {
4519         int ret;
4520
4521         if (num_bytes == 0)
4522                 return 0;
4523
4524         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4525         if (!ret) {
4526                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4527                 return 0;
4528         }
4529
4530         return ret;
4531 }
4532
4533 int btrfs_block_rsv_check(struct btrfs_root *root,
4534                           struct btrfs_block_rsv *block_rsv, int min_factor)
4535 {
4536         u64 num_bytes = 0;
4537         int ret = -ENOSPC;
4538
4539         if (!block_rsv)
4540                 return 0;
4541
4542         spin_lock(&block_rsv->lock);
4543         num_bytes = div_factor(block_rsv->size, min_factor);
4544         if (block_rsv->reserved >= num_bytes)
4545                 ret = 0;
4546         spin_unlock(&block_rsv->lock);
4547
4548         return ret;
4549 }
4550
4551 int btrfs_block_rsv_refill(struct btrfs_root *root,
4552                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4553                            enum btrfs_reserve_flush_enum flush)
4554 {
4555         u64 num_bytes = 0;
4556         int ret = -ENOSPC;
4557
4558         if (!block_rsv)
4559                 return 0;
4560
4561         spin_lock(&block_rsv->lock);
4562         num_bytes = min_reserved;
4563         if (block_rsv->reserved >= num_bytes)
4564                 ret = 0;
4565         else
4566                 num_bytes -= block_rsv->reserved;
4567         spin_unlock(&block_rsv->lock);
4568
4569         if (!ret)
4570                 return 0;
4571
4572         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4573         if (!ret) {
4574                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4575                 return 0;
4576         }
4577
4578         return ret;
4579 }
4580
4581 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4582                             struct btrfs_block_rsv *dst_rsv,
4583                             u64 num_bytes)
4584 {
4585         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4586 }
4587
4588 void btrfs_block_rsv_release(struct btrfs_root *root,
4589                              struct btrfs_block_rsv *block_rsv,
4590                              u64 num_bytes)
4591 {
4592         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4593         if (global_rsv->full || global_rsv == block_rsv ||
4594             block_rsv->space_info != global_rsv->space_info)
4595                 global_rsv = NULL;
4596         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4597                                 num_bytes);
4598 }
4599
4600 /*
4601  * helper to calculate size of global block reservation.
4602  * the desired value is sum of space used by extent tree,
4603  * checksum tree and root tree
4604  */
4605 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4606 {
4607         struct btrfs_space_info *sinfo;
4608         u64 num_bytes;
4609         u64 meta_used;
4610         u64 data_used;
4611         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4612
4613         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4614         spin_lock(&sinfo->lock);
4615         data_used = sinfo->bytes_used;
4616         spin_unlock(&sinfo->lock);
4617
4618         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4619         spin_lock(&sinfo->lock);
4620         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4621                 data_used = 0;
4622         meta_used = sinfo->bytes_used;
4623         spin_unlock(&sinfo->lock);
4624
4625         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4626                     csum_size * 2;
4627         num_bytes += div64_u64(data_used + meta_used, 50);
4628
4629         if (num_bytes * 3 > meta_used)
4630                 num_bytes = div64_u64(meta_used, 3);
4631
4632         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4633 }
4634
4635 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4636 {
4637         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4638         struct btrfs_space_info *sinfo = block_rsv->space_info;
4639         u64 num_bytes;
4640
4641         num_bytes = calc_global_metadata_size(fs_info);
4642
4643         spin_lock(&sinfo->lock);
4644         spin_lock(&block_rsv->lock);
4645
4646         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4647
4648         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4649                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4650                     sinfo->bytes_may_use;
4651
4652         if (sinfo->total_bytes > num_bytes) {
4653                 num_bytes = sinfo->total_bytes - num_bytes;
4654                 block_rsv->reserved += num_bytes;
4655                 sinfo->bytes_may_use += num_bytes;
4656                 trace_btrfs_space_reservation(fs_info, "space_info",
4657                                       sinfo->flags, num_bytes, 1);
4658         }
4659
4660         if (block_rsv->reserved >= block_rsv->size) {
4661                 num_bytes = block_rsv->reserved - block_rsv->size;
4662                 sinfo->bytes_may_use -= num_bytes;
4663                 trace_btrfs_space_reservation(fs_info, "space_info",
4664                                       sinfo->flags, num_bytes, 0);
4665                 sinfo->reservation_progress++;
4666                 block_rsv->reserved = block_rsv->size;
4667                 block_rsv->full = 1;
4668         }
4669
4670         spin_unlock(&block_rsv->lock);
4671         spin_unlock(&sinfo->lock);
4672 }
4673
4674 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4675 {
4676         struct btrfs_space_info *space_info;
4677
4678         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4679         fs_info->chunk_block_rsv.space_info = space_info;
4680
4681         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4682         fs_info->global_block_rsv.space_info = space_info;
4683         fs_info->delalloc_block_rsv.space_info = space_info;
4684         fs_info->trans_block_rsv.space_info = space_info;
4685         fs_info->empty_block_rsv.space_info = space_info;
4686         fs_info->delayed_block_rsv.space_info = space_info;
4687
4688         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4689         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4690         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4691         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4692         if (fs_info->quota_root)
4693                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4694         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4695
4696         update_global_block_rsv(fs_info);
4697 }
4698
4699 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4700 {
4701         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4702                                 (u64)-1);
4703         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4704         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4705         WARN_ON(fs_info->trans_block_rsv.size > 0);
4706         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4707         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4708         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4709         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4710         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4711 }
4712
4713 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4714                                   struct btrfs_root *root)
4715 {
4716         if (!trans->block_rsv)
4717                 return;
4718
4719         if (!trans->bytes_reserved)
4720                 return;
4721
4722         trace_btrfs_space_reservation(root->fs_info, "transaction",
4723                                       trans->transid, trans->bytes_reserved, 0);
4724         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4725         trans->bytes_reserved = 0;
4726 }
4727
4728 /* Can only return 0 or -ENOSPC */
4729 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4730                                   struct inode *inode)
4731 {
4732         struct btrfs_root *root = BTRFS_I(inode)->root;
4733         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4734         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4735
4736         /*
4737          * We need to hold space in order to delete our orphan item once we've
4738          * added it, so this takes the reservation so we can release it later
4739          * when we are truly done with the orphan item.
4740          */
4741         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4742         trace_btrfs_space_reservation(root->fs_info, "orphan",
4743                                       btrfs_ino(inode), num_bytes, 1);
4744         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4745 }
4746
4747 void btrfs_orphan_release_metadata(struct inode *inode)
4748 {
4749         struct btrfs_root *root = BTRFS_I(inode)->root;
4750         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4751         trace_btrfs_space_reservation(root->fs_info, "orphan",
4752                                       btrfs_ino(inode), num_bytes, 0);
4753         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4754 }
4755
4756 /*
4757  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4758  * root: the root of the parent directory
4759  * rsv: block reservation
4760  * items: the number of items that we need do reservation
4761  * qgroup_reserved: used to return the reserved size in qgroup
4762  *
4763  * This function is used to reserve the space for snapshot/subvolume
4764  * creation and deletion. Those operations are different with the
4765  * common file/directory operations, they change two fs/file trees
4766  * and root tree, the number of items that the qgroup reserves is
4767  * different with the free space reservation. So we can not use
4768  * the space reseravtion mechanism in start_transaction().
4769  */
4770 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4771                                      struct btrfs_block_rsv *rsv,
4772                                      int items,
4773                                      u64 *qgroup_reserved,
4774                                      bool use_global_rsv)
4775 {
4776         u64 num_bytes;
4777         int ret;
4778         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4779
4780         if (root->fs_info->quota_enabled) {
4781                 /* One for parent inode, two for dir entries */
4782                 num_bytes = 3 * root->leafsize;
4783                 ret = btrfs_qgroup_reserve(root, num_bytes);
4784                 if (ret)
4785                         return ret;
4786         } else {
4787                 num_bytes = 0;
4788         }
4789
4790         *qgroup_reserved = num_bytes;
4791
4792         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4793         rsv->space_info = __find_space_info(root->fs_info,
4794                                             BTRFS_BLOCK_GROUP_METADATA);
4795         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4796                                   BTRFS_RESERVE_FLUSH_ALL);
4797
4798         if (ret == -ENOSPC && use_global_rsv)
4799                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4800
4801         if (ret) {
4802                 if (*qgroup_reserved)
4803                         btrfs_qgroup_free(root, *qgroup_reserved);
4804         }
4805
4806         return ret;
4807 }
4808
4809 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4810                                       struct btrfs_block_rsv *rsv,
4811                                       u64 qgroup_reserved)
4812 {
4813         btrfs_block_rsv_release(root, rsv, (u64)-1);
4814         if (qgroup_reserved)
4815                 btrfs_qgroup_free(root, qgroup_reserved);
4816 }
4817
4818 /**
4819  * drop_outstanding_extent - drop an outstanding extent
4820  * @inode: the inode we're dropping the extent for
4821  *
4822  * This is called when we are freeing up an outstanding extent, either called
4823  * after an error or after an extent is written.  This will return the number of
4824  * reserved extents that need to be freed.  This must be called with
4825  * BTRFS_I(inode)->lock held.
4826  */
4827 static unsigned drop_outstanding_extent(struct inode *inode)
4828 {
4829         unsigned drop_inode_space = 0;
4830         unsigned dropped_extents = 0;
4831
4832         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4833         BTRFS_I(inode)->outstanding_extents--;
4834
4835         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4836             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4837                                &BTRFS_I(inode)->runtime_flags))
4838                 drop_inode_space = 1;
4839
4840         /*
4841          * If we have more or the same amount of outsanding extents than we have
4842          * reserved then we need to leave the reserved extents count alone.
4843          */
4844         if (BTRFS_I(inode)->outstanding_extents >=
4845             BTRFS_I(inode)->reserved_extents)
4846                 return drop_inode_space;
4847
4848         dropped_extents = BTRFS_I(inode)->reserved_extents -
4849                 BTRFS_I(inode)->outstanding_extents;
4850         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4851         return dropped_extents + drop_inode_space;
4852 }
4853
4854 /**
4855  * calc_csum_metadata_size - return the amount of metada space that must be
4856  *      reserved/free'd for the given bytes.
4857  * @inode: the inode we're manipulating
4858  * @num_bytes: the number of bytes in question
4859  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4860  *
4861  * This adjusts the number of csum_bytes in the inode and then returns the
4862  * correct amount of metadata that must either be reserved or freed.  We
4863  * calculate how many checksums we can fit into one leaf and then divide the
4864  * number of bytes that will need to be checksumed by this value to figure out
4865  * how many checksums will be required.  If we are adding bytes then the number
4866  * may go up and we will return the number of additional bytes that must be
4867  * reserved.  If it is going down we will return the number of bytes that must
4868  * be freed.
4869  *
4870  * This must be called with BTRFS_I(inode)->lock held.
4871  */
4872 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4873                                    int reserve)
4874 {
4875         struct btrfs_root *root = BTRFS_I(inode)->root;
4876         u64 csum_size;
4877         int num_csums_per_leaf;
4878         int num_csums;
4879         int old_csums;
4880
4881         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4882             BTRFS_I(inode)->csum_bytes == 0)
4883                 return 0;
4884
4885         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4886         if (reserve)
4887                 BTRFS_I(inode)->csum_bytes += num_bytes;
4888         else
4889                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4890         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4891         num_csums_per_leaf = (int)div64_u64(csum_size,
4892                                             sizeof(struct btrfs_csum_item) +
4893                                             sizeof(struct btrfs_disk_key));
4894         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4895         num_csums = num_csums + num_csums_per_leaf - 1;
4896         num_csums = num_csums / num_csums_per_leaf;
4897
4898         old_csums = old_csums + num_csums_per_leaf - 1;
4899         old_csums = old_csums / num_csums_per_leaf;
4900
4901         /* No change, no need to reserve more */
4902         if (old_csums == num_csums)
4903                 return 0;
4904
4905         if (reserve)
4906                 return btrfs_calc_trans_metadata_size(root,
4907                                                       num_csums - old_csums);
4908
4909         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4910 }
4911
4912 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4913 {
4914         struct btrfs_root *root = BTRFS_I(inode)->root;
4915         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4916         u64 to_reserve = 0;
4917         u64 csum_bytes;
4918         unsigned nr_extents = 0;
4919         int extra_reserve = 0;
4920         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4921         int ret = 0;
4922         bool delalloc_lock = true;
4923         u64 to_free = 0;
4924         unsigned dropped;
4925
4926         /* If we are a free space inode we need to not flush since we will be in
4927          * the middle of a transaction commit.  We also don't need the delalloc
4928          * mutex since we won't race with anybody.  We need this mostly to make
4929          * lockdep shut its filthy mouth.
4930          */
4931         if (btrfs_is_free_space_inode(inode)) {
4932                 flush = BTRFS_RESERVE_NO_FLUSH;
4933                 delalloc_lock = false;
4934         }
4935
4936         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4937             btrfs_transaction_in_commit(root->fs_info))
4938                 schedule_timeout(1);
4939
4940         if (delalloc_lock)
4941                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4942
4943         num_bytes = ALIGN(num_bytes, root->sectorsize);
4944
4945         spin_lock(&BTRFS_I(inode)->lock);
4946         BTRFS_I(inode)->outstanding_extents++;
4947
4948         if (BTRFS_I(inode)->outstanding_extents >
4949             BTRFS_I(inode)->reserved_extents)
4950                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4951                         BTRFS_I(inode)->reserved_extents;
4952
4953         /*
4954          * Add an item to reserve for updating the inode when we complete the
4955          * delalloc io.
4956          */
4957         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4958                       &BTRFS_I(inode)->runtime_flags)) {
4959                 nr_extents++;
4960                 extra_reserve = 1;
4961         }
4962
4963         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4964         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4965         csum_bytes = BTRFS_I(inode)->csum_bytes;
4966         spin_unlock(&BTRFS_I(inode)->lock);
4967
4968         if (root->fs_info->quota_enabled) {
4969                 ret = btrfs_qgroup_reserve(root, num_bytes +
4970                                            nr_extents * root->leafsize);
4971                 if (ret)
4972                         goto out_fail;
4973         }
4974
4975         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4976         if (unlikely(ret)) {
4977                 if (root->fs_info->quota_enabled)
4978                         btrfs_qgroup_free(root, num_bytes +
4979                                                 nr_extents * root->leafsize);
4980                 goto out_fail;
4981         }
4982
4983         spin_lock(&BTRFS_I(inode)->lock);
4984         if (extra_reserve) {
4985                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4986                         &BTRFS_I(inode)->runtime_flags);
4987                 nr_extents--;
4988         }
4989         BTRFS_I(inode)->reserved_extents += nr_extents;
4990         spin_unlock(&BTRFS_I(inode)->lock);
4991
4992         if (delalloc_lock)
4993                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4994
4995         if (to_reserve)
4996                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4997                                               btrfs_ino(inode), to_reserve, 1);
4998         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4999
5000         return 0;
5001
5002 out_fail:
5003         spin_lock(&BTRFS_I(inode)->lock);
5004         dropped = drop_outstanding_extent(inode);
5005         /*
5006          * If the inodes csum_bytes is the same as the original
5007          * csum_bytes then we know we haven't raced with any free()ers
5008          * so we can just reduce our inodes csum bytes and carry on.
5009          */
5010         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5011                 calc_csum_metadata_size(inode, num_bytes, 0);
5012         } else {
5013                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5014                 u64 bytes;
5015
5016                 /*
5017                  * This is tricky, but first we need to figure out how much we
5018                  * free'd from any free-ers that occured during this
5019                  * reservation, so we reset ->csum_bytes to the csum_bytes
5020                  * before we dropped our lock, and then call the free for the
5021                  * number of bytes that were freed while we were trying our
5022                  * reservation.
5023                  */
5024                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5025                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5026                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5027
5028
5029                 /*
5030                  * Now we need to see how much we would have freed had we not
5031                  * been making this reservation and our ->csum_bytes were not
5032                  * artificially inflated.
5033                  */
5034                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5035                 bytes = csum_bytes - orig_csum_bytes;
5036                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5037
5038                 /*
5039                  * Now reset ->csum_bytes to what it should be.  If bytes is
5040                  * more than to_free then we would have free'd more space had we
5041                  * not had an artificially high ->csum_bytes, so we need to free
5042                  * the remainder.  If bytes is the same or less then we don't
5043                  * need to do anything, the other free-ers did the correct
5044                  * thing.
5045                  */
5046                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5047                 if (bytes > to_free)
5048                         to_free = bytes - to_free;
5049                 else
5050                         to_free = 0;
5051         }
5052         spin_unlock(&BTRFS_I(inode)->lock);
5053         if (dropped)
5054                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5055
5056         if (to_free) {
5057                 btrfs_block_rsv_release(root, block_rsv, to_free);
5058                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5059                                               btrfs_ino(inode), to_free, 0);
5060         }
5061         if (delalloc_lock)
5062                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5063         return ret;
5064 }
5065
5066 /**
5067  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5068  * @inode: the inode to release the reservation for
5069  * @num_bytes: the number of bytes we're releasing
5070  *
5071  * This will release the metadata reservation for an inode.  This can be called
5072  * once we complete IO for a given set of bytes to release their metadata
5073  * reservations.
5074  */
5075 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5076 {
5077         struct btrfs_root *root = BTRFS_I(inode)->root;
5078         u64 to_free = 0;
5079         unsigned dropped;
5080
5081         num_bytes = ALIGN(num_bytes, root->sectorsize);
5082         spin_lock(&BTRFS_I(inode)->lock);
5083         dropped = drop_outstanding_extent(inode);
5084
5085         if (num_bytes)
5086                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5087         spin_unlock(&BTRFS_I(inode)->lock);
5088         if (dropped > 0)
5089                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5090
5091         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5092                                       btrfs_ino(inode), to_free, 0);
5093         if (root->fs_info->quota_enabled) {
5094                 btrfs_qgroup_free(root, num_bytes +
5095                                         dropped * root->leafsize);
5096         }
5097
5098         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5099                                 to_free);
5100 }
5101
5102 /**
5103  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5104  * @inode: inode we're writing to
5105  * @num_bytes: the number of bytes we want to allocate
5106  *
5107  * This will do the following things
5108  *
5109  * o reserve space in the data space info for num_bytes
5110  * o reserve space in the metadata space info based on number of outstanding
5111  *   extents and how much csums will be needed
5112  * o add to the inodes ->delalloc_bytes
5113  * o add it to the fs_info's delalloc inodes list.
5114  *
5115  * This will return 0 for success and -ENOSPC if there is no space left.
5116  */
5117 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5118 {
5119         int ret;
5120
5121         ret = btrfs_check_data_free_space(inode, num_bytes);
5122         if (ret)
5123                 return ret;
5124
5125         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5126         if (ret) {
5127                 btrfs_free_reserved_data_space(inode, num_bytes);
5128                 return ret;
5129         }
5130
5131         return 0;
5132 }
5133
5134 /**
5135  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5136  * @inode: inode we're releasing space for
5137  * @num_bytes: the number of bytes we want to free up
5138  *
5139  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5140  * called in the case that we don't need the metadata AND data reservations
5141  * anymore.  So if there is an error or we insert an inline extent.
5142  *
5143  * This function will release the metadata space that was not used and will
5144  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5145  * list if there are no delalloc bytes left.
5146  */
5147 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5148 {
5149         btrfs_delalloc_release_metadata(inode, num_bytes);
5150         btrfs_free_reserved_data_space(inode, num_bytes);
5151 }
5152
5153 static int update_block_group(struct btrfs_root *root,
5154                               u64 bytenr, u64 num_bytes, int alloc)
5155 {
5156         struct btrfs_block_group_cache *cache = NULL;
5157         struct btrfs_fs_info *info = root->fs_info;
5158         u64 total = num_bytes;
5159         u64 old_val;
5160         u64 byte_in_group;
5161         int factor;
5162
5163         /* block accounting for super block */
5164         spin_lock(&info->delalloc_root_lock);
5165         old_val = btrfs_super_bytes_used(info->super_copy);
5166         if (alloc)
5167                 old_val += num_bytes;
5168         else
5169                 old_val -= num_bytes;
5170         btrfs_set_super_bytes_used(info->super_copy, old_val);
5171         spin_unlock(&info->delalloc_root_lock);
5172
5173         while (total) {
5174                 cache = btrfs_lookup_block_group(info, bytenr);
5175                 if (!cache)
5176                         return -ENOENT;
5177                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5178                                     BTRFS_BLOCK_GROUP_RAID1 |
5179                                     BTRFS_BLOCK_GROUP_RAID10))
5180                         factor = 2;
5181                 else
5182                         factor = 1;
5183                 /*
5184                  * If this block group has free space cache written out, we
5185                  * need to make sure to load it if we are removing space.  This
5186                  * is because we need the unpinning stage to actually add the
5187                  * space back to the block group, otherwise we will leak space.
5188                  */
5189                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5190                         cache_block_group(cache, 1);
5191
5192                 byte_in_group = bytenr - cache->key.objectid;
5193                 WARN_ON(byte_in_group > cache->key.offset);
5194
5195                 spin_lock(&cache->space_info->lock);
5196                 spin_lock(&cache->lock);
5197
5198                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5199                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5200                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5201
5202                 cache->dirty = 1;
5203                 old_val = btrfs_block_group_used(&cache->item);
5204                 num_bytes = min(total, cache->key.offset - byte_in_group);
5205                 if (alloc) {
5206                         old_val += num_bytes;
5207                         btrfs_set_block_group_used(&cache->item, old_val);
5208                         cache->reserved -= num_bytes;
5209                         cache->space_info->bytes_reserved -= num_bytes;
5210                         cache->space_info->bytes_used += num_bytes;
5211                         cache->space_info->disk_used += num_bytes * factor;
5212                         spin_unlock(&cache->lock);
5213                         spin_unlock(&cache->space_info->lock);
5214                 } else {
5215                         old_val -= num_bytes;
5216                         btrfs_set_block_group_used(&cache->item, old_val);
5217                         cache->pinned += num_bytes;
5218                         cache->space_info->bytes_pinned += num_bytes;
5219                         cache->space_info->bytes_used -= num_bytes;
5220                         cache->space_info->disk_used -= num_bytes * factor;
5221                         spin_unlock(&cache->lock);
5222                         spin_unlock(&cache->space_info->lock);
5223
5224                         set_extent_dirty(info->pinned_extents,
5225                                          bytenr, bytenr + num_bytes - 1,
5226                                          GFP_NOFS | __GFP_NOFAIL);
5227                 }
5228                 btrfs_put_block_group(cache);
5229                 total -= num_bytes;
5230                 bytenr += num_bytes;
5231         }
5232         return 0;
5233 }
5234
5235 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5236 {
5237         struct btrfs_block_group_cache *cache;
5238         u64 bytenr;
5239
5240         spin_lock(&root->fs_info->block_group_cache_lock);
5241         bytenr = root->fs_info->first_logical_byte;
5242         spin_unlock(&root->fs_info->block_group_cache_lock);
5243
5244         if (bytenr < (u64)-1)
5245                 return bytenr;
5246
5247         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5248         if (!cache)
5249                 return 0;
5250
5251         bytenr = cache->key.objectid;
5252         btrfs_put_block_group(cache);
5253
5254         return bytenr;
5255 }
5256
5257 static int pin_down_extent(struct btrfs_root *root,
5258                            struct btrfs_block_group_cache *cache,
5259                            u64 bytenr, u64 num_bytes, int reserved)
5260 {
5261         spin_lock(&cache->space_info->lock);
5262         spin_lock(&cache->lock);
5263         cache->pinned += num_bytes;
5264         cache->space_info->bytes_pinned += num_bytes;
5265         if (reserved) {
5266                 cache->reserved -= num_bytes;
5267                 cache->space_info->bytes_reserved -= num_bytes;
5268         }
5269         spin_unlock(&cache->lock);
5270         spin_unlock(&cache->space_info->lock);
5271
5272         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5273                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5274         return 0;
5275 }
5276
5277 /*
5278  * this function must be called within transaction
5279  */
5280 int btrfs_pin_extent(struct btrfs_root *root,
5281                      u64 bytenr, u64 num_bytes, int reserved)
5282 {
5283         struct btrfs_block_group_cache *cache;
5284
5285         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5286         BUG_ON(!cache); /* Logic error */
5287
5288         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5289
5290         btrfs_put_block_group(cache);
5291         return 0;
5292 }
5293
5294 /*
5295  * this function must be called within transaction
5296  */
5297 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5298                                     u64 bytenr, u64 num_bytes)
5299 {
5300         struct btrfs_block_group_cache *cache;
5301         int ret;
5302
5303         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5304         if (!cache)
5305                 return -EINVAL;
5306
5307         /*
5308          * pull in the free space cache (if any) so that our pin
5309          * removes the free space from the cache.  We have load_only set
5310          * to one because the slow code to read in the free extents does check
5311          * the pinned extents.
5312          */
5313         cache_block_group(cache, 1);
5314
5315         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5316
5317         /* remove us from the free space cache (if we're there at all) */
5318         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5319         btrfs_put_block_group(cache);
5320         return ret;
5321 }
5322
5323 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5324 {
5325         int ret;
5326         struct btrfs_block_group_cache *block_group;
5327         struct btrfs_caching_control *caching_ctl;
5328
5329         block_group = btrfs_lookup_block_group(root->fs_info, start);
5330         if (!block_group)
5331                 return -EINVAL;
5332
5333         cache_block_group(block_group, 0);
5334         caching_ctl = get_caching_control(block_group);
5335
5336         if (!caching_ctl) {
5337                 /* Logic error */
5338                 BUG_ON(!block_group_cache_done(block_group));
5339                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5340         } else {
5341                 mutex_lock(&caching_ctl->mutex);
5342
5343                 if (start >= caching_ctl->progress) {
5344                         ret = add_excluded_extent(root, start, num_bytes);
5345                 } else if (start + num_bytes <= caching_ctl->progress) {
5346                         ret = btrfs_remove_free_space(block_group,
5347                                                       start, num_bytes);
5348                 } else {
5349                         num_bytes = caching_ctl->progress - start;
5350                         ret = btrfs_remove_free_space(block_group,
5351                                                       start, num_bytes);
5352                         if (ret)
5353                                 goto out_lock;
5354
5355                         num_bytes = (start + num_bytes) -
5356                                 caching_ctl->progress;
5357                         start = caching_ctl->progress;
5358                         ret = add_excluded_extent(root, start, num_bytes);
5359                 }
5360 out_lock:
5361                 mutex_unlock(&caching_ctl->mutex);
5362                 put_caching_control(caching_ctl);
5363         }
5364         btrfs_put_block_group(block_group);
5365         return ret;
5366 }
5367
5368 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5369                                  struct extent_buffer *eb)
5370 {
5371         struct btrfs_file_extent_item *item;
5372         struct btrfs_key key;
5373         int found_type;
5374         int i;
5375
5376         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5377                 return 0;
5378
5379         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5380                 btrfs_item_key_to_cpu(eb, &key, i);
5381                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5382                         continue;
5383                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5384                 found_type = btrfs_file_extent_type(eb, item);
5385                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5386                         continue;
5387                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5388                         continue;
5389                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5390                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5391                 __exclude_logged_extent(log, key.objectid, key.offset);
5392         }
5393
5394         return 0;
5395 }
5396
5397 /**
5398  * btrfs_update_reserved_bytes - update the block_group and space info counters
5399  * @cache:      The cache we are manipulating
5400  * @num_bytes:  The number of bytes in question
5401  * @reserve:    One of the reservation enums
5402  *
5403  * This is called by the allocator when it reserves space, or by somebody who is
5404  * freeing space that was never actually used on disk.  For example if you
5405  * reserve some space for a new leaf in transaction A and before transaction A
5406  * commits you free that leaf, you call this with reserve set to 0 in order to
5407  * clear the reservation.
5408  *
5409  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5410  * ENOSPC accounting.  For data we handle the reservation through clearing the
5411  * delalloc bits in the io_tree.  We have to do this since we could end up
5412  * allocating less disk space for the amount of data we have reserved in the
5413  * case of compression.
5414  *
5415  * If this is a reservation and the block group has become read only we cannot
5416  * make the reservation and return -EAGAIN, otherwise this function always
5417  * succeeds.
5418  */
5419 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5420                                        u64 num_bytes, int reserve)
5421 {
5422         struct btrfs_space_info *space_info = cache->space_info;
5423         int ret = 0;
5424
5425         spin_lock(&space_info->lock);
5426         spin_lock(&cache->lock);
5427         if (reserve != RESERVE_FREE) {
5428                 if (cache->ro) {
5429                         ret = -EAGAIN;
5430                 } else {
5431                         cache->reserved += num_bytes;
5432                         space_info->bytes_reserved += num_bytes;
5433                         if (reserve == RESERVE_ALLOC) {
5434                                 trace_btrfs_space_reservation(cache->fs_info,
5435                                                 "space_info", space_info->flags,
5436                                                 num_bytes, 0);
5437                                 space_info->bytes_may_use -= num_bytes;
5438                         }
5439                 }
5440         } else {
5441                 if (cache->ro)
5442                         space_info->bytes_readonly += num_bytes;
5443                 cache->reserved -= num_bytes;
5444                 space_info->bytes_reserved -= num_bytes;
5445                 space_info->reservation_progress++;
5446         }
5447         spin_unlock(&cache->lock);
5448         spin_unlock(&space_info->lock);
5449         return ret;
5450 }
5451
5452 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5453                                 struct btrfs_root *root)
5454 {
5455         struct btrfs_fs_info *fs_info = root->fs_info;
5456         struct btrfs_caching_control *next;
5457         struct btrfs_caching_control *caching_ctl;
5458         struct btrfs_block_group_cache *cache;
5459         struct btrfs_space_info *space_info;
5460
5461         down_write(&fs_info->extent_commit_sem);
5462
5463         list_for_each_entry_safe(caching_ctl, next,
5464                                  &fs_info->caching_block_groups, list) {
5465                 cache = caching_ctl->block_group;
5466                 if (block_group_cache_done(cache)) {
5467                         cache->last_byte_to_unpin = (u64)-1;
5468                         list_del_init(&caching_ctl->list);
5469                         put_caching_control(caching_ctl);
5470                 } else {
5471                         cache->last_byte_to_unpin = caching_ctl->progress;
5472                 }
5473         }
5474
5475         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5476                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5477         else
5478                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5479
5480         up_write(&fs_info->extent_commit_sem);
5481
5482         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5483                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5484
5485         update_global_block_rsv(fs_info);
5486 }
5487
5488 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5489 {
5490         struct btrfs_fs_info *fs_info = root->fs_info;
5491         struct btrfs_block_group_cache *cache = NULL;
5492         struct btrfs_space_info *space_info;
5493         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5494         u64 len;
5495         bool readonly;
5496
5497         while (start <= end) {
5498                 readonly = false;
5499                 if (!cache ||
5500                     start >= cache->key.objectid + cache->key.offset) {
5501                         if (cache)
5502                                 btrfs_put_block_group(cache);
5503                         cache = btrfs_lookup_block_group(fs_info, start);
5504                         BUG_ON(!cache); /* Logic error */
5505                 }
5506
5507                 len = cache->key.objectid + cache->key.offset - start;
5508                 len = min(len, end + 1 - start);
5509
5510                 if (start < cache->last_byte_to_unpin) {
5511                         len = min(len, cache->last_byte_to_unpin - start);
5512                         btrfs_add_free_space(cache, start, len);
5513                 }
5514
5515                 start += len;
5516                 space_info = cache->space_info;
5517
5518                 spin_lock(&space_info->lock);
5519                 spin_lock(&cache->lock);
5520                 cache->pinned -= len;
5521                 space_info->bytes_pinned -= len;
5522                 if (cache->ro) {
5523                         space_info->bytes_readonly += len;
5524                         readonly = true;
5525                 }
5526                 spin_unlock(&cache->lock);
5527                 if (!readonly && global_rsv->space_info == space_info) {
5528                         spin_lock(&global_rsv->lock);
5529                         if (!global_rsv->full) {
5530                                 len = min(len, global_rsv->size -
5531                                           global_rsv->reserved);
5532                                 global_rsv->reserved += len;
5533                                 space_info->bytes_may_use += len;
5534                                 if (global_rsv->reserved >= global_rsv->size)
5535                                         global_rsv->full = 1;
5536                         }
5537                         spin_unlock(&global_rsv->lock);
5538                 }
5539                 spin_unlock(&space_info->lock);
5540         }
5541
5542         if (cache)
5543                 btrfs_put_block_group(cache);
5544         return 0;
5545 }
5546
5547 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5548                                struct btrfs_root *root)
5549 {
5550         struct btrfs_fs_info *fs_info = root->fs_info;
5551         struct extent_io_tree *unpin;
5552         u64 start;
5553         u64 end;
5554         int ret;
5555
5556         if (trans->aborted)
5557                 return 0;
5558
5559         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5560                 unpin = &fs_info->freed_extents[1];
5561         else
5562                 unpin = &fs_info->freed_extents[0];
5563
5564         while (1) {
5565                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5566                                             EXTENT_DIRTY, NULL);
5567                 if (ret)
5568                         break;
5569
5570                 if (btrfs_test_opt(root, DISCARD))
5571                         ret = btrfs_discard_extent(root, start,
5572                                                    end + 1 - start, NULL);
5573
5574                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5575                 unpin_extent_range(root, start, end);
5576                 cond_resched();
5577         }
5578
5579         return 0;
5580 }
5581
5582 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5583                              u64 owner, u64 root_objectid)
5584 {
5585         struct btrfs_space_info *space_info;
5586         u64 flags;
5587
5588         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5589                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5590                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5591                 else
5592                         flags = BTRFS_BLOCK_GROUP_METADATA;
5593         } else {
5594                 flags = BTRFS_BLOCK_GROUP_DATA;
5595         }
5596
5597         space_info = __find_space_info(fs_info, flags);
5598         BUG_ON(!space_info); /* Logic bug */
5599         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5600 }
5601
5602
5603 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5604                                 struct btrfs_root *root,
5605                                 u64 bytenr, u64 num_bytes, u64 parent,
5606                                 u64 root_objectid, u64 owner_objectid,
5607                                 u64 owner_offset, int refs_to_drop,
5608                                 struct btrfs_delayed_extent_op *extent_op)
5609 {
5610         struct btrfs_key key;
5611         struct btrfs_path *path;
5612         struct btrfs_fs_info *info = root->fs_info;
5613         struct btrfs_root *extent_root = info->extent_root;
5614         struct extent_buffer *leaf;
5615         struct btrfs_extent_item *ei;
5616         struct btrfs_extent_inline_ref *iref;
5617         int ret;
5618         int is_data;
5619         int extent_slot = 0;
5620         int found_extent = 0;
5621         int num_to_del = 1;
5622         u32 item_size;
5623         u64 refs;
5624         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5625                                                  SKINNY_METADATA);
5626
5627         path = btrfs_alloc_path();
5628         if (!path)
5629                 return -ENOMEM;
5630
5631         path->reada = 1;
5632         path->leave_spinning = 1;
5633
5634         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5635         BUG_ON(!is_data && refs_to_drop != 1);
5636
5637         if (is_data)
5638                 skinny_metadata = 0;
5639
5640         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5641                                     bytenr, num_bytes, parent,
5642                                     root_objectid, owner_objectid,
5643                                     owner_offset);
5644         if (ret == 0) {
5645                 extent_slot = path->slots[0];
5646                 while (extent_slot >= 0) {
5647                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5648                                               extent_slot);
5649                         if (key.objectid != bytenr)
5650                                 break;
5651                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5652                             key.offset == num_bytes) {
5653                                 found_extent = 1;
5654                                 break;
5655                         }
5656                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5657                             key.offset == owner_objectid) {
5658                                 found_extent = 1;
5659                                 break;
5660                         }
5661                         if (path->slots[0] - extent_slot > 5)
5662                                 break;
5663                         extent_slot--;
5664                 }
5665 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5666                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5667                 if (found_extent && item_size < sizeof(*ei))
5668                         found_extent = 0;
5669 #endif
5670                 if (!found_extent) {
5671                         BUG_ON(iref);
5672                         ret = remove_extent_backref(trans, extent_root, path,
5673                                                     NULL, refs_to_drop,
5674                                                     is_data);
5675                         if (ret) {
5676                                 btrfs_abort_transaction(trans, extent_root, ret);
5677                                 goto out;
5678                         }
5679                         btrfs_release_path(path);
5680                         path->leave_spinning = 1;
5681
5682                         key.objectid = bytenr;
5683                         key.type = BTRFS_EXTENT_ITEM_KEY;
5684                         key.offset = num_bytes;
5685
5686                         if (!is_data && skinny_metadata) {
5687                                 key.type = BTRFS_METADATA_ITEM_KEY;
5688                                 key.offset = owner_objectid;
5689                         }
5690
5691                         ret = btrfs_search_slot(trans, extent_root,
5692                                                 &key, path, -1, 1);
5693                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5694                                 /*
5695                                  * Couldn't find our skinny metadata item,
5696                                  * see if we have ye olde extent item.
5697                                  */
5698                                 path->slots[0]--;
5699                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5700                                                       path->slots[0]);
5701                                 if (key.objectid == bytenr &&
5702                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5703                                     key.offset == num_bytes)
5704                                         ret = 0;
5705                         }
5706
5707                         if (ret > 0 && skinny_metadata) {
5708                                 skinny_metadata = false;
5709                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5710                                 key.offset = num_bytes;
5711                                 btrfs_release_path(path);
5712                                 ret = btrfs_search_slot(trans, extent_root,
5713                                                         &key, path, -1, 1);
5714                         }
5715
5716                         if (ret) {
5717                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5718                                         ret, (unsigned long long)bytenr);
5719                                 if (ret > 0)
5720                                         btrfs_print_leaf(extent_root,
5721                                                          path->nodes[0]);
5722                         }
5723                         if (ret < 0) {
5724                                 btrfs_abort_transaction(trans, extent_root, ret);
5725                                 goto out;
5726                         }
5727                         extent_slot = path->slots[0];
5728                 }
5729         } else if (ret == -ENOENT) {
5730                 btrfs_print_leaf(extent_root, path->nodes[0]);
5731                 WARN_ON(1);
5732                 btrfs_err(info,
5733                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5734                         (unsigned long long)bytenr,
5735                         (unsigned long long)parent,
5736                         (unsigned long long)root_objectid,
5737                         (unsigned long long)owner_objectid,
5738                         (unsigned long long)owner_offset);
5739         } else {
5740                 btrfs_abort_transaction(trans, extent_root, ret);
5741                 goto out;
5742         }
5743
5744         leaf = path->nodes[0];
5745         item_size = btrfs_item_size_nr(leaf, extent_slot);
5746 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5747         if (item_size < sizeof(*ei)) {
5748                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5749                 ret = convert_extent_item_v0(trans, extent_root, path,
5750                                              owner_objectid, 0);
5751                 if (ret < 0) {
5752                         btrfs_abort_transaction(trans, extent_root, ret);
5753                         goto out;
5754                 }
5755
5756                 btrfs_release_path(path);
5757                 path->leave_spinning = 1;
5758
5759                 key.objectid = bytenr;
5760                 key.type = BTRFS_EXTENT_ITEM_KEY;
5761                 key.offset = num_bytes;
5762
5763                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5764                                         -1, 1);
5765                 if (ret) {
5766                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5767                                 ret, (unsigned long long)bytenr);
5768                         btrfs_print_leaf(extent_root, path->nodes[0]);
5769                 }
5770                 if (ret < 0) {
5771                         btrfs_abort_transaction(trans, extent_root, ret);
5772                         goto out;
5773                 }
5774
5775                 extent_slot = path->slots[0];
5776                 leaf = path->nodes[0];
5777                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5778         }
5779 #endif
5780         BUG_ON(item_size < sizeof(*ei));
5781         ei = btrfs_item_ptr(leaf, extent_slot,
5782                             struct btrfs_extent_item);
5783         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5784             key.type == BTRFS_EXTENT_ITEM_KEY) {
5785                 struct btrfs_tree_block_info *bi;
5786                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5787                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5788                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5789         }
5790
5791         refs = btrfs_extent_refs(leaf, ei);
5792         if (refs < refs_to_drop) {
5793                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5794                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5795                 ret = -EINVAL;
5796                 btrfs_abort_transaction(trans, extent_root, ret);
5797                 goto out;
5798         }
5799         refs -= refs_to_drop;
5800
5801         if (refs > 0) {
5802                 if (extent_op)
5803                         __run_delayed_extent_op(extent_op, leaf, ei);
5804                 /*
5805                  * In the case of inline back ref, reference count will
5806                  * be updated by remove_extent_backref
5807                  */
5808                 if (iref) {
5809                         BUG_ON(!found_extent);
5810                 } else {
5811                         btrfs_set_extent_refs(leaf, ei, refs);
5812                         btrfs_mark_buffer_dirty(leaf);
5813                 }
5814                 if (found_extent) {
5815                         ret = remove_extent_backref(trans, extent_root, path,
5816                                                     iref, refs_to_drop,
5817                                                     is_data);
5818                         if (ret) {
5819                                 btrfs_abort_transaction(trans, extent_root, ret);
5820                                 goto out;
5821                         }
5822                 }
5823                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5824                                  root_objectid);
5825         } else {
5826                 if (found_extent) {
5827                         BUG_ON(is_data && refs_to_drop !=
5828                                extent_data_ref_count(root, path, iref));
5829                         if (iref) {
5830                                 BUG_ON(path->slots[0] != extent_slot);
5831                         } else {
5832                                 BUG_ON(path->slots[0] != extent_slot + 1);
5833                                 path->slots[0] = extent_slot;
5834                                 num_to_del = 2;
5835                         }
5836                 }
5837
5838                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5839                                       num_to_del);
5840                 if (ret) {
5841                         btrfs_abort_transaction(trans, extent_root, ret);
5842                         goto out;
5843                 }
5844                 btrfs_release_path(path);
5845
5846                 if (is_data) {
5847                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5848                         if (ret) {
5849                                 btrfs_abort_transaction(trans, extent_root, ret);
5850                                 goto out;
5851                         }
5852                 }
5853
5854                 ret = update_block_group(root, bytenr, num_bytes, 0);
5855                 if (ret) {
5856                         btrfs_abort_transaction(trans, extent_root, ret);
5857                         goto out;
5858                 }
5859         }
5860 out:
5861         btrfs_free_path(path);
5862         return ret;
5863 }
5864
5865 /*
5866  * when we free an block, it is possible (and likely) that we free the last
5867  * delayed ref for that extent as well.  This searches the delayed ref tree for
5868  * a given extent, and if there are no other delayed refs to be processed, it
5869  * removes it from the tree.
5870  */
5871 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5872                                       struct btrfs_root *root, u64 bytenr)
5873 {
5874         struct btrfs_delayed_ref_head *head;
5875         struct btrfs_delayed_ref_root *delayed_refs;
5876         struct btrfs_delayed_ref_node *ref;
5877         struct rb_node *node;
5878         int ret = 0;
5879
5880         delayed_refs = &trans->transaction->delayed_refs;
5881         spin_lock(&delayed_refs->lock);
5882         head = btrfs_find_delayed_ref_head(trans, bytenr);
5883         if (!head)
5884                 goto out;
5885
5886         node = rb_prev(&head->node.rb_node);
5887         if (!node)
5888                 goto out;
5889
5890         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5891
5892         /* there are still entries for this ref, we can't drop it */
5893         if (ref->bytenr == bytenr)
5894                 goto out;
5895
5896         if (head->extent_op) {
5897                 if (!head->must_insert_reserved)
5898                         goto out;
5899                 btrfs_free_delayed_extent_op(head->extent_op);
5900                 head->extent_op = NULL;
5901         }
5902
5903         /*
5904          * waiting for the lock here would deadlock.  If someone else has it
5905          * locked they are already in the process of dropping it anyway
5906          */
5907         if (!mutex_trylock(&head->mutex))
5908                 goto out;
5909
5910         /*
5911          * at this point we have a head with no other entries.  Go
5912          * ahead and process it.
5913          */
5914         head->node.in_tree = 0;
5915         rb_erase(&head->node.rb_node, &delayed_refs->root);
5916
5917         delayed_refs->num_entries--;
5918
5919         /*
5920          * we don't take a ref on the node because we're removing it from the
5921          * tree, so we just steal the ref the tree was holding.
5922          */
5923         delayed_refs->num_heads--;
5924         if (list_empty(&head->cluster))
5925                 delayed_refs->num_heads_ready--;
5926
5927         list_del_init(&head->cluster);
5928         spin_unlock(&delayed_refs->lock);
5929
5930         BUG_ON(head->extent_op);
5931         if (head->must_insert_reserved)
5932                 ret = 1;
5933
5934         mutex_unlock(&head->mutex);
5935         btrfs_put_delayed_ref(&head->node);
5936         return ret;
5937 out:
5938         spin_unlock(&delayed_refs->lock);
5939         return 0;
5940 }
5941
5942 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5943                            struct btrfs_root *root,
5944                            struct extent_buffer *buf,
5945                            u64 parent, int last_ref)
5946 {
5947         struct btrfs_block_group_cache *cache = NULL;
5948         int pin = 1;
5949         int ret;
5950
5951         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5952                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5953                                         buf->start, buf->len,
5954                                         parent, root->root_key.objectid,
5955                                         btrfs_header_level(buf),
5956                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5957                 BUG_ON(ret); /* -ENOMEM */
5958         }
5959
5960         if (!last_ref)
5961                 return;
5962
5963         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5964
5965         if (btrfs_header_generation(buf) == trans->transid) {
5966                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5967                         ret = check_ref_cleanup(trans, root, buf->start);
5968                         if (!ret)
5969                                 goto out;
5970                 }
5971
5972                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5973                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5974                         goto out;
5975                 }
5976
5977                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5978
5979                 btrfs_add_free_space(cache, buf->start, buf->len);
5980                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5981                 pin = 0;
5982         }
5983 out:
5984         if (pin)
5985                 add_pinned_bytes(root->fs_info, buf->len,
5986                                  btrfs_header_level(buf),
5987                                  root->root_key.objectid);
5988
5989         /*
5990          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5991          * anymore.
5992          */
5993         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5994         btrfs_put_block_group(cache);
5995 }
5996
5997 /* Can return -ENOMEM */
5998 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5999                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6000                       u64 owner, u64 offset, int for_cow)
6001 {
6002         int ret;
6003         struct btrfs_fs_info *fs_info = root->fs_info;
6004
6005         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6006
6007         /*
6008          * tree log blocks never actually go into the extent allocation
6009          * tree, just update pinning info and exit early.
6010          */
6011         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6012                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6013                 /* unlocks the pinned mutex */
6014                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6015                 ret = 0;
6016         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6017                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6018                                         num_bytes,
6019                                         parent, root_objectid, (int)owner,
6020                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
6021         } else {
6022                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6023                                                 num_bytes,
6024                                                 parent, root_objectid, owner,
6025                                                 offset, BTRFS_DROP_DELAYED_REF,
6026                                                 NULL, for_cow);
6027         }
6028         return ret;
6029 }
6030
6031 static u64 stripe_align(struct btrfs_root *root,
6032                         struct btrfs_block_group_cache *cache,
6033                         u64 val, u64 num_bytes)
6034 {
6035         u64 ret = ALIGN(val, root->stripesize);
6036         return ret;
6037 }
6038
6039 /*
6040  * when we wait for progress in the block group caching, its because
6041  * our allocation attempt failed at least once.  So, we must sleep
6042  * and let some progress happen before we try again.
6043  *
6044  * This function will sleep at least once waiting for new free space to
6045  * show up, and then it will check the block group free space numbers
6046  * for our min num_bytes.  Another option is to have it go ahead
6047  * and look in the rbtree for a free extent of a given size, but this
6048  * is a good start.
6049  *
6050  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6051  * any of the information in this block group.
6052  */
6053 static noinline void
6054 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6055                                 u64 num_bytes)
6056 {
6057         struct btrfs_caching_control *caching_ctl;
6058
6059         caching_ctl = get_caching_control(cache);
6060         if (!caching_ctl)
6061                 return;
6062
6063         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6064                    (cache->free_space_ctl->free_space >= num_bytes));
6065
6066         put_caching_control(caching_ctl);
6067 }
6068
6069 static noinline int
6070 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6071 {
6072         struct btrfs_caching_control *caching_ctl;
6073         int ret = 0;
6074
6075         caching_ctl = get_caching_control(cache);
6076         if (!caching_ctl)
6077                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6078
6079         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6080         if (cache->cached == BTRFS_CACHE_ERROR)
6081                 ret = -EIO;
6082         put_caching_control(caching_ctl);
6083         return ret;
6084 }
6085
6086 int __get_raid_index(u64 flags)
6087 {
6088         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6089                 return BTRFS_RAID_RAID10;
6090         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6091                 return BTRFS_RAID_RAID1;
6092         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6093                 return BTRFS_RAID_DUP;
6094         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6095                 return BTRFS_RAID_RAID0;
6096         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6097                 return BTRFS_RAID_RAID5;
6098         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6099                 return BTRFS_RAID_RAID6;
6100
6101         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6102 }
6103
6104 static int get_block_group_index(struct btrfs_block_group_cache *cache)
6105 {
6106         return __get_raid_index(cache->flags);
6107 }
6108
6109 enum btrfs_loop_type {
6110         LOOP_CACHING_NOWAIT = 0,
6111         LOOP_CACHING_WAIT = 1,
6112         LOOP_ALLOC_CHUNK = 2,
6113         LOOP_NO_EMPTY_SIZE = 3,
6114 };
6115
6116 /*
6117  * walks the btree of allocated extents and find a hole of a given size.
6118  * The key ins is changed to record the hole:
6119  * ins->objectid == block start
6120  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6121  * ins->offset == number of blocks
6122  * Any available blocks before search_start are skipped.
6123  */
6124 static noinline int find_free_extent(struct btrfs_root *orig_root,
6125                                      u64 num_bytes, u64 empty_size,
6126                                      u64 hint_byte, struct btrfs_key *ins,
6127                                      u64 flags)
6128 {
6129         int ret = 0;
6130         struct btrfs_root *root = orig_root->fs_info->extent_root;
6131         struct btrfs_free_cluster *last_ptr = NULL;
6132         struct btrfs_block_group_cache *block_group = NULL;
6133         struct btrfs_block_group_cache *used_block_group;
6134         u64 search_start = 0;
6135         int empty_cluster = 2 * 1024 * 1024;
6136         struct btrfs_space_info *space_info;
6137         int loop = 0;
6138         int index = __get_raid_index(flags);
6139         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6140                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6141         bool found_uncached_bg = false;
6142         bool failed_cluster_refill = false;
6143         bool failed_alloc = false;
6144         bool use_cluster = true;
6145         bool have_caching_bg = false;
6146
6147         WARN_ON(num_bytes < root->sectorsize);
6148         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6149         ins->objectid = 0;
6150         ins->offset = 0;
6151
6152         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6153
6154         space_info = __find_space_info(root->fs_info, flags);
6155         if (!space_info) {
6156                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6157                 return -ENOSPC;
6158         }
6159
6160         /*
6161          * If the space info is for both data and metadata it means we have a
6162          * small filesystem and we can't use the clustering stuff.
6163          */
6164         if (btrfs_mixed_space_info(space_info))
6165                 use_cluster = false;
6166
6167         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6168                 last_ptr = &root->fs_info->meta_alloc_cluster;
6169                 if (!btrfs_test_opt(root, SSD))
6170                         empty_cluster = 64 * 1024;
6171         }
6172
6173         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6174             btrfs_test_opt(root, SSD)) {
6175                 last_ptr = &root->fs_info->data_alloc_cluster;
6176         }
6177
6178         if (last_ptr) {
6179                 spin_lock(&last_ptr->lock);
6180                 if (last_ptr->block_group)
6181                         hint_byte = last_ptr->window_start;
6182                 spin_unlock(&last_ptr->lock);
6183         }
6184
6185         search_start = max(search_start, first_logical_byte(root, 0));
6186         search_start = max(search_start, hint_byte);
6187
6188         if (!last_ptr)
6189                 empty_cluster = 0;
6190
6191         if (search_start == hint_byte) {
6192                 block_group = btrfs_lookup_block_group(root->fs_info,
6193                                                        search_start);
6194                 used_block_group = block_group;
6195                 /*
6196                  * we don't want to use the block group if it doesn't match our
6197                  * allocation bits, or if its not cached.
6198                  *
6199                  * However if we are re-searching with an ideal block group
6200                  * picked out then we don't care that the block group is cached.
6201                  */
6202                 if (block_group && block_group_bits(block_group, flags) &&
6203                     block_group->cached != BTRFS_CACHE_NO) {
6204                         down_read(&space_info->groups_sem);
6205                         if (list_empty(&block_group->list) ||
6206                             block_group->ro) {
6207                                 /*
6208                                  * someone is removing this block group,
6209                                  * we can't jump into the have_block_group
6210                                  * target because our list pointers are not
6211                                  * valid
6212                                  */
6213                                 btrfs_put_block_group(block_group);
6214                                 up_read(&space_info->groups_sem);
6215                         } else {
6216                                 index = get_block_group_index(block_group);
6217                                 goto have_block_group;
6218                         }
6219                 } else if (block_group) {
6220                         btrfs_put_block_group(block_group);
6221                 }
6222         }
6223 search:
6224         have_caching_bg = false;
6225         down_read(&space_info->groups_sem);
6226         list_for_each_entry(block_group, &space_info->block_groups[index],
6227                             list) {
6228                 u64 offset;
6229                 int cached;
6230
6231                 used_block_group = block_group;
6232                 btrfs_get_block_group(block_group);
6233                 search_start = block_group->key.objectid;
6234
6235                 /*
6236                  * this can happen if we end up cycling through all the
6237                  * raid types, but we want to make sure we only allocate
6238                  * for the proper type.
6239                  */
6240                 if (!block_group_bits(block_group, flags)) {
6241                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6242                                 BTRFS_BLOCK_GROUP_RAID1 |
6243                                 BTRFS_BLOCK_GROUP_RAID5 |
6244                                 BTRFS_BLOCK_GROUP_RAID6 |
6245                                 BTRFS_BLOCK_GROUP_RAID10;
6246
6247                         /*
6248                          * if they asked for extra copies and this block group
6249                          * doesn't provide them, bail.  This does allow us to
6250                          * fill raid0 from raid1.
6251                          */
6252                         if ((flags & extra) && !(block_group->flags & extra))
6253                                 goto loop;
6254                 }
6255
6256 have_block_group:
6257                 cached = block_group_cache_done(block_group);
6258                 if (unlikely(!cached)) {
6259                         found_uncached_bg = true;
6260                         ret = cache_block_group(block_group, 0);
6261                         BUG_ON(ret < 0);
6262                         ret = 0;
6263                 }
6264
6265                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6266                         goto loop;
6267                 if (unlikely(block_group->ro))
6268                         goto loop;
6269
6270                 /*
6271                  * Ok we want to try and use the cluster allocator, so
6272                  * lets look there
6273                  */
6274                 if (last_ptr) {
6275                         unsigned long aligned_cluster;
6276                         /*
6277                          * the refill lock keeps out other
6278                          * people trying to start a new cluster
6279                          */
6280                         spin_lock(&last_ptr->refill_lock);
6281                         used_block_group = last_ptr->block_group;
6282                         if (used_block_group != block_group &&
6283                             (!used_block_group ||
6284                              used_block_group->ro ||
6285                              !block_group_bits(used_block_group, flags))) {
6286                                 used_block_group = block_group;
6287                                 goto refill_cluster;
6288                         }
6289
6290                         if (used_block_group != block_group)
6291                                 btrfs_get_block_group(used_block_group);
6292
6293                         offset = btrfs_alloc_from_cluster(used_block_group,
6294                           last_ptr, num_bytes, used_block_group->key.objectid);
6295                         if (offset) {
6296                                 /* we have a block, we're done */
6297                                 spin_unlock(&last_ptr->refill_lock);
6298                                 trace_btrfs_reserve_extent_cluster(root,
6299                                         block_group, search_start, num_bytes);
6300                                 goto checks;
6301                         }
6302
6303                         WARN_ON(last_ptr->block_group != used_block_group);
6304                         if (used_block_group != block_group) {
6305                                 btrfs_put_block_group(used_block_group);
6306                                 used_block_group = block_group;
6307                         }
6308 refill_cluster:
6309                         BUG_ON(used_block_group != block_group);
6310                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6311                          * set up a new clusters, so lets just skip it
6312                          * and let the allocator find whatever block
6313                          * it can find.  If we reach this point, we
6314                          * will have tried the cluster allocator
6315                          * plenty of times and not have found
6316                          * anything, so we are likely way too
6317                          * fragmented for the clustering stuff to find
6318                          * anything.
6319                          *
6320                          * However, if the cluster is taken from the
6321                          * current block group, release the cluster
6322                          * first, so that we stand a better chance of
6323                          * succeeding in the unclustered
6324                          * allocation.  */
6325                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6326                             last_ptr->block_group != block_group) {
6327                                 spin_unlock(&last_ptr->refill_lock);
6328                                 goto unclustered_alloc;
6329                         }
6330
6331                         /*
6332                          * this cluster didn't work out, free it and
6333                          * start over
6334                          */
6335                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6336
6337                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6338                                 spin_unlock(&last_ptr->refill_lock);
6339                                 goto unclustered_alloc;
6340                         }
6341
6342                         aligned_cluster = max_t(unsigned long,
6343                                                 empty_cluster + empty_size,
6344                                               block_group->full_stripe_len);
6345
6346                         /* allocate a cluster in this block group */
6347                         ret = btrfs_find_space_cluster(root, block_group,
6348                                                        last_ptr, search_start,
6349                                                        num_bytes,
6350                                                        aligned_cluster);
6351                         if (ret == 0) {
6352                                 /*
6353                                  * now pull our allocation out of this
6354                                  * cluster
6355                                  */
6356                                 offset = btrfs_alloc_from_cluster(block_group,
6357                                                   last_ptr, num_bytes,
6358                                                   search_start);
6359                                 if (offset) {
6360                                         /* we found one, proceed */
6361                                         spin_unlock(&last_ptr->refill_lock);
6362                                         trace_btrfs_reserve_extent_cluster(root,
6363                                                 block_group, search_start,
6364                                                 num_bytes);
6365                                         goto checks;
6366                                 }
6367                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6368                                    && !failed_cluster_refill) {
6369                                 spin_unlock(&last_ptr->refill_lock);
6370
6371                                 failed_cluster_refill = true;
6372                                 wait_block_group_cache_progress(block_group,
6373                                        num_bytes + empty_cluster + empty_size);
6374                                 goto have_block_group;
6375                         }
6376
6377                         /*
6378                          * at this point we either didn't find a cluster
6379                          * or we weren't able to allocate a block from our
6380                          * cluster.  Free the cluster we've been trying
6381                          * to use, and go to the next block group
6382                          */
6383                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6384                         spin_unlock(&last_ptr->refill_lock);
6385                         goto loop;
6386                 }
6387
6388 unclustered_alloc:
6389                 spin_lock(&block_group->free_space_ctl->tree_lock);
6390                 if (cached &&
6391                     block_group->free_space_ctl->free_space <
6392                     num_bytes + empty_cluster + empty_size) {
6393                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6394                         goto loop;
6395                 }
6396                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6397
6398                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6399                                                     num_bytes, empty_size);
6400                 /*
6401                  * If we didn't find a chunk, and we haven't failed on this
6402                  * block group before, and this block group is in the middle of
6403                  * caching and we are ok with waiting, then go ahead and wait
6404                  * for progress to be made, and set failed_alloc to true.
6405                  *
6406                  * If failed_alloc is true then we've already waited on this
6407                  * block group once and should move on to the next block group.
6408                  */
6409                 if (!offset && !failed_alloc && !cached &&
6410                     loop > LOOP_CACHING_NOWAIT) {
6411                         wait_block_group_cache_progress(block_group,
6412                                                 num_bytes + empty_size);
6413                         failed_alloc = true;
6414                         goto have_block_group;
6415                 } else if (!offset) {
6416                         if (!cached)
6417                                 have_caching_bg = true;
6418                         goto loop;
6419                 }
6420 checks:
6421                 search_start = stripe_align(root, used_block_group,
6422                                             offset, num_bytes);
6423
6424                 /* move on to the next group */
6425                 if (search_start + num_bytes >
6426                     used_block_group->key.objectid + used_block_group->key.offset) {
6427                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6428                         goto loop;
6429                 }
6430
6431                 if (offset < search_start)
6432                         btrfs_add_free_space(used_block_group, offset,
6433                                              search_start - offset);
6434                 BUG_ON(offset > search_start);
6435
6436                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6437                                                   alloc_type);
6438                 if (ret == -EAGAIN) {
6439                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6440                         goto loop;
6441                 }
6442
6443                 /* we are all good, lets return */
6444                 ins->objectid = search_start;
6445                 ins->offset = num_bytes;
6446
6447                 trace_btrfs_reserve_extent(orig_root, block_group,
6448                                            search_start, num_bytes);
6449                 if (used_block_group != block_group)
6450                         btrfs_put_block_group(used_block_group);
6451                 btrfs_put_block_group(block_group);
6452                 break;
6453 loop:
6454                 failed_cluster_refill = false;
6455                 failed_alloc = false;
6456                 BUG_ON(index != get_block_group_index(block_group));
6457                 if (used_block_group != block_group)
6458                         btrfs_put_block_group(used_block_group);
6459                 btrfs_put_block_group(block_group);
6460         }
6461         up_read(&space_info->groups_sem);
6462
6463         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6464                 goto search;
6465
6466         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6467                 goto search;
6468
6469         /*
6470          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6471          *                      caching kthreads as we move along
6472          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6473          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6474          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6475          *                      again
6476          */
6477         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6478                 index = 0;
6479                 loop++;
6480                 if (loop == LOOP_ALLOC_CHUNK) {
6481                         struct btrfs_trans_handle *trans;
6482
6483                         trans = btrfs_join_transaction(root);
6484                         if (IS_ERR(trans)) {
6485                                 ret = PTR_ERR(trans);
6486                                 goto out;
6487                         }
6488
6489                         ret = do_chunk_alloc(trans, root, flags,
6490                                              CHUNK_ALLOC_FORCE);
6491                         /*
6492                          * Do not bail out on ENOSPC since we
6493                          * can do more things.
6494                          */
6495                         if (ret < 0 && ret != -ENOSPC)
6496                                 btrfs_abort_transaction(trans,
6497                                                         root, ret);
6498                         else
6499                                 ret = 0;
6500                         btrfs_end_transaction(trans, root);
6501                         if (ret)
6502                                 goto out;
6503                 }
6504
6505                 if (loop == LOOP_NO_EMPTY_SIZE) {
6506                         empty_size = 0;
6507                         empty_cluster = 0;
6508                 }
6509
6510                 goto search;
6511         } else if (!ins->objectid) {
6512                 ret = -ENOSPC;
6513         } else if (ins->objectid) {
6514                 ret = 0;
6515         }
6516 out:
6517
6518         return ret;
6519 }
6520
6521 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6522                             int dump_block_groups)
6523 {
6524         struct btrfs_block_group_cache *cache;
6525         int index = 0;
6526
6527         spin_lock(&info->lock);
6528         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6529                (unsigned long long)info->flags,
6530                (unsigned long long)(info->total_bytes - info->bytes_used -
6531                                     info->bytes_pinned - info->bytes_reserved -
6532                                     info->bytes_readonly),
6533                (info->full) ? "" : "not ");
6534         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6535                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6536                (unsigned long long)info->total_bytes,
6537                (unsigned long long)info->bytes_used,
6538                (unsigned long long)info->bytes_pinned,
6539                (unsigned long long)info->bytes_reserved,
6540                (unsigned long long)info->bytes_may_use,
6541                (unsigned long long)info->bytes_readonly);
6542         spin_unlock(&info->lock);
6543
6544         if (!dump_block_groups)
6545                 return;
6546
6547         down_read(&info->groups_sem);
6548 again:
6549         list_for_each_entry(cache, &info->block_groups[index], list) {
6550                 spin_lock(&cache->lock);
6551                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6552                        (unsigned long long)cache->key.objectid,
6553                        (unsigned long long)cache->key.offset,
6554                        (unsigned long long)btrfs_block_group_used(&cache->item),
6555                        (unsigned long long)cache->pinned,
6556                        (unsigned long long)cache->reserved,
6557                        cache->ro ? "[readonly]" : "");
6558                 btrfs_dump_free_space(cache, bytes);
6559                 spin_unlock(&cache->lock);
6560         }
6561         if (++index < BTRFS_NR_RAID_TYPES)
6562                 goto again;
6563         up_read(&info->groups_sem);
6564 }
6565
6566 int btrfs_reserve_extent(struct btrfs_root *root,
6567                          u64 num_bytes, u64 min_alloc_size,
6568                          u64 empty_size, u64 hint_byte,
6569                          struct btrfs_key *ins, int is_data)
6570 {
6571         bool final_tried = false;
6572         u64 flags;
6573         int ret;
6574
6575         flags = btrfs_get_alloc_profile(root, is_data);
6576 again:
6577         WARN_ON(num_bytes < root->sectorsize);
6578         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6579                                flags);
6580
6581         if (ret == -ENOSPC) {
6582                 if (!final_tried) {
6583                         num_bytes = num_bytes >> 1;
6584                         num_bytes = round_down(num_bytes, root->sectorsize);
6585                         num_bytes = max(num_bytes, min_alloc_size);
6586                         if (num_bytes == min_alloc_size)
6587                                 final_tried = true;
6588                         goto again;
6589                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6590                         struct btrfs_space_info *sinfo;
6591
6592                         sinfo = __find_space_info(root->fs_info, flags);
6593                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6594                                 (unsigned long long)flags,
6595                                 (unsigned long long)num_bytes);
6596                         if (sinfo)
6597                                 dump_space_info(sinfo, num_bytes, 1);
6598                 }
6599         }
6600
6601         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6602
6603         return ret;
6604 }
6605
6606 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6607                                         u64 start, u64 len, int pin)
6608 {
6609         struct btrfs_block_group_cache *cache;
6610         int ret = 0;
6611
6612         cache = btrfs_lookup_block_group(root->fs_info, start);
6613         if (!cache) {
6614                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6615                         (unsigned long long)start);
6616                 return -ENOSPC;
6617         }
6618
6619         if (btrfs_test_opt(root, DISCARD))
6620                 ret = btrfs_discard_extent(root, start, len, NULL);
6621
6622         if (pin)
6623                 pin_down_extent(root, cache, start, len, 1);
6624         else {
6625                 btrfs_add_free_space(cache, start, len);
6626                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6627         }
6628         btrfs_put_block_group(cache);
6629
6630         trace_btrfs_reserved_extent_free(root, start, len);
6631
6632         return ret;
6633 }
6634
6635 int btrfs_free_reserved_extent(struct btrfs_root *root,
6636                                         u64 start, u64 len)
6637 {
6638         return __btrfs_free_reserved_extent(root, start, len, 0);
6639 }
6640
6641 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6642                                        u64 start, u64 len)
6643 {
6644         return __btrfs_free_reserved_extent(root, start, len, 1);
6645 }
6646
6647 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6648                                       struct btrfs_root *root,
6649                                       u64 parent, u64 root_objectid,
6650                                       u64 flags, u64 owner, u64 offset,
6651                                       struct btrfs_key *ins, int ref_mod)
6652 {
6653         int ret;
6654         struct btrfs_fs_info *fs_info = root->fs_info;
6655         struct btrfs_extent_item *extent_item;
6656         struct btrfs_extent_inline_ref *iref;
6657         struct btrfs_path *path;
6658         struct extent_buffer *leaf;
6659         int type;
6660         u32 size;
6661
6662         if (parent > 0)
6663                 type = BTRFS_SHARED_DATA_REF_KEY;
6664         else
6665                 type = BTRFS_EXTENT_DATA_REF_KEY;
6666
6667         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6668
6669         path = btrfs_alloc_path();
6670         if (!path)
6671                 return -ENOMEM;
6672
6673         path->leave_spinning = 1;
6674         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6675                                       ins, size);
6676         if (ret) {
6677                 btrfs_free_path(path);
6678                 return ret;
6679         }
6680
6681         leaf = path->nodes[0];
6682         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6683                                      struct btrfs_extent_item);
6684         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6685         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6686         btrfs_set_extent_flags(leaf, extent_item,
6687                                flags | BTRFS_EXTENT_FLAG_DATA);
6688
6689         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6690         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6691         if (parent > 0) {
6692                 struct btrfs_shared_data_ref *ref;
6693                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6694                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6695                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6696         } else {
6697                 struct btrfs_extent_data_ref *ref;
6698                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6699                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6700                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6701                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6702                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6703         }
6704
6705         btrfs_mark_buffer_dirty(path->nodes[0]);
6706         btrfs_free_path(path);
6707
6708         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6709         if (ret) { /* -ENOENT, logic error */
6710                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6711                         (unsigned long long)ins->objectid,
6712                         (unsigned long long)ins->offset);
6713                 BUG();
6714         }
6715         return ret;
6716 }
6717
6718 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6719                                      struct btrfs_root *root,
6720                                      u64 parent, u64 root_objectid,
6721                                      u64 flags, struct btrfs_disk_key *key,
6722                                      int level, struct btrfs_key *ins)
6723 {
6724         int ret;
6725         struct btrfs_fs_info *fs_info = root->fs_info;
6726         struct btrfs_extent_item *extent_item;
6727         struct btrfs_tree_block_info *block_info;
6728         struct btrfs_extent_inline_ref *iref;
6729         struct btrfs_path *path;
6730         struct extent_buffer *leaf;
6731         u32 size = sizeof(*extent_item) + sizeof(*iref);
6732         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6733                                                  SKINNY_METADATA);
6734
6735         if (!skinny_metadata)
6736                 size += sizeof(*block_info);
6737
6738         path = btrfs_alloc_path();
6739         if (!path)
6740                 return -ENOMEM;
6741
6742         path->leave_spinning = 1;
6743         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6744                                       ins, size);
6745         if (ret) {
6746                 btrfs_free_path(path);
6747                 return ret;
6748         }
6749
6750         leaf = path->nodes[0];
6751         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6752                                      struct btrfs_extent_item);
6753         btrfs_set_extent_refs(leaf, extent_item, 1);
6754         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6755         btrfs_set_extent_flags(leaf, extent_item,
6756                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6757
6758         if (skinny_metadata) {
6759                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6760         } else {
6761                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6762                 btrfs_set_tree_block_key(leaf, block_info, key);
6763                 btrfs_set_tree_block_level(leaf, block_info, level);
6764                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6765         }
6766
6767         if (parent > 0) {
6768                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6769                 btrfs_set_extent_inline_ref_type(leaf, iref,
6770                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6771                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6772         } else {
6773                 btrfs_set_extent_inline_ref_type(leaf, iref,
6774                                                  BTRFS_TREE_BLOCK_REF_KEY);
6775                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6776         }
6777
6778         btrfs_mark_buffer_dirty(leaf);
6779         btrfs_free_path(path);
6780
6781         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6782         if (ret) { /* -ENOENT, logic error */
6783                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6784                         (unsigned long long)ins->objectid,
6785                         (unsigned long long)ins->offset);
6786                 BUG();
6787         }
6788         return ret;
6789 }
6790
6791 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6792                                      struct btrfs_root *root,
6793                                      u64 root_objectid, u64 owner,
6794                                      u64 offset, struct btrfs_key *ins)
6795 {
6796         int ret;
6797
6798         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6799
6800         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6801                                          ins->offset, 0,
6802                                          root_objectid, owner, offset,
6803                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6804         return ret;
6805 }
6806
6807 /*
6808  * this is used by the tree logging recovery code.  It records that
6809  * an extent has been allocated and makes sure to clear the free
6810  * space cache bits as well
6811  */
6812 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6813                                    struct btrfs_root *root,
6814                                    u64 root_objectid, u64 owner, u64 offset,
6815                                    struct btrfs_key *ins)
6816 {
6817         int ret;
6818         struct btrfs_block_group_cache *block_group;
6819
6820         /*
6821          * Mixed block groups will exclude before processing the log so we only
6822          * need to do the exlude dance if this fs isn't mixed.
6823          */
6824         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6825                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6826                 if (ret)
6827                         return ret;
6828         }
6829
6830         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6831         if (!block_group)
6832                 return -EINVAL;
6833
6834         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6835                                           RESERVE_ALLOC_NO_ACCOUNT);
6836         BUG_ON(ret); /* logic error */
6837         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6838                                          0, owner, offset, ins, 1);
6839         btrfs_put_block_group(block_group);
6840         return ret;
6841 }
6842
6843 static struct extent_buffer *
6844 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6845                       u64 bytenr, u32 blocksize, int level)
6846 {
6847         struct extent_buffer *buf;
6848
6849         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6850         if (!buf)
6851                 return ERR_PTR(-ENOMEM);
6852         btrfs_set_header_generation(buf, trans->transid);
6853         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6854         btrfs_tree_lock(buf);
6855         clean_tree_block(trans, root, buf);
6856         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6857
6858         btrfs_set_lock_blocking(buf);
6859         btrfs_set_buffer_uptodate(buf);
6860
6861         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6862                 /*
6863                  * we allow two log transactions at a time, use different
6864                  * EXENT bit to differentiate dirty pages.
6865                  */
6866                 if (root->log_transid % 2 == 0)
6867                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6868                                         buf->start + buf->len - 1, GFP_NOFS);
6869                 else
6870                         set_extent_new(&root->dirty_log_pages, buf->start,
6871                                         buf->start + buf->len - 1, GFP_NOFS);
6872         } else {
6873                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6874                          buf->start + buf->len - 1, GFP_NOFS);
6875         }
6876         trans->blocks_used++;
6877         /* this returns a buffer locked for blocking */
6878         return buf;
6879 }
6880
6881 static struct btrfs_block_rsv *
6882 use_block_rsv(struct btrfs_trans_handle *trans,
6883               struct btrfs_root *root, u32 blocksize)
6884 {
6885         struct btrfs_block_rsv *block_rsv;
6886         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6887         int ret;
6888         bool global_updated = false;
6889
6890         block_rsv = get_block_rsv(trans, root);
6891
6892         if (unlikely(block_rsv->size == 0))
6893                 goto try_reserve;
6894 again:
6895         ret = block_rsv_use_bytes(block_rsv, blocksize);
6896         if (!ret)
6897                 return block_rsv;
6898
6899         if (block_rsv->failfast)
6900                 return ERR_PTR(ret);
6901
6902         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6903                 global_updated = true;
6904                 update_global_block_rsv(root->fs_info);
6905                 goto again;
6906         }
6907
6908         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6909                 static DEFINE_RATELIMIT_STATE(_rs,
6910                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6911                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6912                 if (__ratelimit(&_rs))
6913                         WARN(1, KERN_DEBUG
6914                                 "btrfs: block rsv returned %d\n", ret);
6915         }
6916 try_reserve:
6917         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6918                                      BTRFS_RESERVE_NO_FLUSH);
6919         if (!ret)
6920                 return block_rsv;
6921         /*
6922          * If we couldn't reserve metadata bytes try and use some from
6923          * the global reserve if its space type is the same as the global
6924          * reservation.
6925          */
6926         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6927             block_rsv->space_info == global_rsv->space_info) {
6928                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6929                 if (!ret)
6930                         return global_rsv;
6931         }
6932         return ERR_PTR(ret);
6933 }
6934
6935 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6936                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6937 {
6938         block_rsv_add_bytes(block_rsv, blocksize, 0);
6939         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6940 }
6941
6942 /*
6943  * finds a free extent and does all the dirty work required for allocation
6944  * returns the key for the extent through ins, and a tree buffer for
6945  * the first block of the extent through buf.
6946  *
6947  * returns the tree buffer or NULL.
6948  */
6949 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6950                                         struct btrfs_root *root, u32 blocksize,
6951                                         u64 parent, u64 root_objectid,
6952                                         struct btrfs_disk_key *key, int level,
6953                                         u64 hint, u64 empty_size)
6954 {
6955         struct btrfs_key ins;
6956         struct btrfs_block_rsv *block_rsv;
6957         struct extent_buffer *buf;
6958         u64 flags = 0;
6959         int ret;
6960         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6961                                                  SKINNY_METADATA);
6962
6963         block_rsv = use_block_rsv(trans, root, blocksize);
6964         if (IS_ERR(block_rsv))
6965                 return ERR_CAST(block_rsv);
6966
6967         ret = btrfs_reserve_extent(root, blocksize, blocksize,
6968                                    empty_size, hint, &ins, 0);
6969         if (ret) {
6970                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6971                 return ERR_PTR(ret);
6972         }
6973
6974         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6975                                     blocksize, level);
6976         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6977
6978         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6979                 if (parent == 0)
6980                         parent = ins.objectid;
6981                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6982         } else
6983                 BUG_ON(parent > 0);
6984
6985         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6986                 struct btrfs_delayed_extent_op *extent_op;
6987                 extent_op = btrfs_alloc_delayed_extent_op();
6988                 BUG_ON(!extent_op); /* -ENOMEM */
6989                 if (key)
6990                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6991                 else
6992                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6993                 extent_op->flags_to_set = flags;
6994                 if (skinny_metadata)
6995                         extent_op->update_key = 0;
6996                 else
6997                         extent_op->update_key = 1;
6998                 extent_op->update_flags = 1;
6999                 extent_op->is_data = 0;
7000                 extent_op->level = level;
7001
7002                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7003                                         ins.objectid,
7004                                         ins.offset, parent, root_objectid,
7005                                         level, BTRFS_ADD_DELAYED_EXTENT,
7006                                         extent_op, 0);
7007                 BUG_ON(ret); /* -ENOMEM */
7008         }
7009         return buf;
7010 }
7011
7012 struct walk_control {
7013         u64 refs[BTRFS_MAX_LEVEL];
7014         u64 flags[BTRFS_MAX_LEVEL];
7015         struct btrfs_key update_progress;
7016         int stage;
7017         int level;
7018         int shared_level;
7019         int update_ref;
7020         int keep_locks;
7021         int reada_slot;
7022         int reada_count;
7023         int for_reloc;
7024 };
7025
7026 #define DROP_REFERENCE  1
7027 #define UPDATE_BACKREF  2
7028
7029 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7030                                      struct btrfs_root *root,
7031                                      struct walk_control *wc,
7032                                      struct btrfs_path *path)
7033 {
7034         u64 bytenr;
7035         u64 generation;
7036         u64 refs;
7037         u64 flags;
7038         u32 nritems;
7039         u32 blocksize;
7040         struct btrfs_key key;
7041         struct extent_buffer *eb;
7042         int ret;
7043         int slot;
7044         int nread = 0;
7045
7046         if (path->slots[wc->level] < wc->reada_slot) {
7047                 wc->reada_count = wc->reada_count * 2 / 3;
7048                 wc->reada_count = max(wc->reada_count, 2);
7049         } else {
7050                 wc->reada_count = wc->reada_count * 3 / 2;
7051                 wc->reada_count = min_t(int, wc->reada_count,
7052                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7053         }
7054
7055         eb = path->nodes[wc->level];
7056         nritems = btrfs_header_nritems(eb);
7057         blocksize = btrfs_level_size(root, wc->level - 1);
7058
7059         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7060                 if (nread >= wc->reada_count)
7061                         break;
7062
7063                 cond_resched();
7064                 bytenr = btrfs_node_blockptr(eb, slot);
7065                 generation = btrfs_node_ptr_generation(eb, slot);
7066
7067                 if (slot == path->slots[wc->level])
7068                         goto reada;
7069
7070                 if (wc->stage == UPDATE_BACKREF &&
7071                     generation <= root->root_key.offset)
7072                         continue;
7073
7074                 /* We don't lock the tree block, it's OK to be racy here */
7075                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7076                                                wc->level - 1, 1, &refs,
7077                                                &flags);
7078                 /* We don't care about errors in readahead. */
7079                 if (ret < 0)
7080                         continue;
7081                 BUG_ON(refs == 0);
7082
7083                 if (wc->stage == DROP_REFERENCE) {
7084                         if (refs == 1)
7085                                 goto reada;
7086
7087                         if (wc->level == 1 &&
7088                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7089                                 continue;
7090                         if (!wc->update_ref ||
7091                             generation <= root->root_key.offset)
7092                                 continue;
7093                         btrfs_node_key_to_cpu(eb, &key, slot);
7094                         ret = btrfs_comp_cpu_keys(&key,
7095                                                   &wc->update_progress);
7096                         if (ret < 0)
7097                                 continue;
7098                 } else {
7099                         if (wc->level == 1 &&
7100                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7101                                 continue;
7102                 }
7103 reada:
7104                 ret = readahead_tree_block(root, bytenr, blocksize,
7105                                            generation);
7106                 if (ret)
7107                         break;
7108                 nread++;
7109         }
7110         wc->reada_slot = slot;
7111 }
7112
7113 /*
7114  * helper to process tree block while walking down the tree.
7115  *
7116  * when wc->stage == UPDATE_BACKREF, this function updates
7117  * back refs for pointers in the block.
7118  *
7119  * NOTE: return value 1 means we should stop walking down.
7120  */
7121 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7122                                    struct btrfs_root *root,
7123                                    struct btrfs_path *path,
7124                                    struct walk_control *wc, int lookup_info)
7125 {
7126         int level = wc->level;
7127         struct extent_buffer *eb = path->nodes[level];
7128         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7129         int ret;
7130
7131         if (wc->stage == UPDATE_BACKREF &&
7132             btrfs_header_owner(eb) != root->root_key.objectid)
7133                 return 1;
7134
7135         /*
7136          * when reference count of tree block is 1, it won't increase
7137          * again. once full backref flag is set, we never clear it.
7138          */
7139         if (lookup_info &&
7140             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7141              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7142                 BUG_ON(!path->locks[level]);
7143                 ret = btrfs_lookup_extent_info(trans, root,
7144                                                eb->start, level, 1,
7145                                                &wc->refs[level],
7146                                                &wc->flags[level]);
7147                 BUG_ON(ret == -ENOMEM);
7148                 if (ret)
7149                         return ret;
7150                 BUG_ON(wc->refs[level] == 0);
7151         }
7152
7153         if (wc->stage == DROP_REFERENCE) {
7154                 if (wc->refs[level] > 1)
7155                         return 1;
7156
7157                 if (path->locks[level] && !wc->keep_locks) {
7158                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7159                         path->locks[level] = 0;
7160                 }
7161                 return 0;
7162         }
7163
7164         /* wc->stage == UPDATE_BACKREF */
7165         if (!(wc->flags[level] & flag)) {
7166                 BUG_ON(!path->locks[level]);
7167                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7168                 BUG_ON(ret); /* -ENOMEM */
7169                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7170                 BUG_ON(ret); /* -ENOMEM */
7171                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7172                                                   eb->len, flag,
7173                                                   btrfs_header_level(eb), 0);
7174                 BUG_ON(ret); /* -ENOMEM */
7175                 wc->flags[level] |= flag;
7176         }
7177
7178         /*
7179          * the block is shared by multiple trees, so it's not good to
7180          * keep the tree lock
7181          */
7182         if (path->locks[level] && level > 0) {
7183                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7184                 path->locks[level] = 0;
7185         }
7186         return 0;
7187 }
7188
7189 /*
7190  * helper to process tree block pointer.
7191  *
7192  * when wc->stage == DROP_REFERENCE, this function checks
7193  * reference count of the block pointed to. if the block
7194  * is shared and we need update back refs for the subtree
7195  * rooted at the block, this function changes wc->stage to
7196  * UPDATE_BACKREF. if the block is shared and there is no
7197  * need to update back, this function drops the reference
7198  * to the block.
7199  *
7200  * NOTE: return value 1 means we should stop walking down.
7201  */
7202 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7203                                  struct btrfs_root *root,
7204                                  struct btrfs_path *path,
7205                                  struct walk_control *wc, int *lookup_info)
7206 {
7207         u64 bytenr;
7208         u64 generation;
7209         u64 parent;
7210         u32 blocksize;
7211         struct btrfs_key key;
7212         struct extent_buffer *next;
7213         int level = wc->level;
7214         int reada = 0;
7215         int ret = 0;
7216
7217         generation = btrfs_node_ptr_generation(path->nodes[level],
7218                                                path->slots[level]);
7219         /*
7220          * if the lower level block was created before the snapshot
7221          * was created, we know there is no need to update back refs
7222          * for the subtree
7223          */
7224         if (wc->stage == UPDATE_BACKREF &&
7225             generation <= root->root_key.offset) {
7226                 *lookup_info = 1;
7227                 return 1;
7228         }
7229
7230         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7231         blocksize = btrfs_level_size(root, level - 1);
7232
7233         next = btrfs_find_tree_block(root, bytenr, blocksize);
7234         if (!next) {
7235                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7236                 if (!next)
7237                         return -ENOMEM;
7238                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7239                                                level - 1);
7240                 reada = 1;
7241         }
7242         btrfs_tree_lock(next);
7243         btrfs_set_lock_blocking(next);
7244
7245         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7246                                        &wc->refs[level - 1],
7247                                        &wc->flags[level - 1]);
7248         if (ret < 0) {
7249                 btrfs_tree_unlock(next);
7250                 return ret;
7251         }
7252
7253         if (unlikely(wc->refs[level - 1] == 0)) {
7254                 btrfs_err(root->fs_info, "Missing references.");
7255                 BUG();
7256         }
7257         *lookup_info = 0;
7258
7259         if (wc->stage == DROP_REFERENCE) {
7260                 if (wc->refs[level - 1] > 1) {
7261                         if (level == 1 &&
7262                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7263                                 goto skip;
7264
7265                         if (!wc->update_ref ||
7266                             generation <= root->root_key.offset)
7267                                 goto skip;
7268
7269                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7270                                               path->slots[level]);
7271                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7272                         if (ret < 0)
7273                                 goto skip;
7274
7275                         wc->stage = UPDATE_BACKREF;
7276                         wc->shared_level = level - 1;
7277                 }
7278         } else {
7279                 if (level == 1 &&
7280                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7281                         goto skip;
7282         }
7283
7284         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7285                 btrfs_tree_unlock(next);
7286                 free_extent_buffer(next);
7287                 next = NULL;
7288                 *lookup_info = 1;
7289         }
7290
7291         if (!next) {
7292                 if (reada && level == 1)
7293                         reada_walk_down(trans, root, wc, path);
7294                 next = read_tree_block(root, bytenr, blocksize, generation);
7295                 if (!next || !extent_buffer_uptodate(next)) {
7296                         free_extent_buffer(next);
7297                         return -EIO;
7298                 }
7299                 btrfs_tree_lock(next);
7300                 btrfs_set_lock_blocking(next);
7301         }
7302
7303         level--;
7304         BUG_ON(level != btrfs_header_level(next));
7305         path->nodes[level] = next;
7306         path->slots[level] = 0;
7307         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7308         wc->level = level;
7309         if (wc->level == 1)
7310                 wc->reada_slot = 0;
7311         return 0;
7312 skip:
7313         wc->refs[level - 1] = 0;
7314         wc->flags[level - 1] = 0;
7315         if (wc->stage == DROP_REFERENCE) {
7316                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7317                         parent = path->nodes[level]->start;
7318                 } else {
7319                         BUG_ON(root->root_key.objectid !=
7320                                btrfs_header_owner(path->nodes[level]));
7321                         parent = 0;
7322                 }
7323
7324                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7325                                 root->root_key.objectid, level - 1, 0, 0);
7326                 BUG_ON(ret); /* -ENOMEM */
7327         }
7328         btrfs_tree_unlock(next);
7329         free_extent_buffer(next);
7330         *lookup_info = 1;
7331         return 1;
7332 }
7333
7334 /*
7335  * helper to process tree block while walking up the tree.
7336  *
7337  * when wc->stage == DROP_REFERENCE, this function drops
7338  * reference count on the block.
7339  *
7340  * when wc->stage == UPDATE_BACKREF, this function changes
7341  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7342  * to UPDATE_BACKREF previously while processing the block.
7343  *
7344  * NOTE: return value 1 means we should stop walking up.
7345  */
7346 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7347                                  struct btrfs_root *root,
7348                                  struct btrfs_path *path,
7349                                  struct walk_control *wc)
7350 {
7351         int ret;
7352         int level = wc->level;
7353         struct extent_buffer *eb = path->nodes[level];
7354         u64 parent = 0;
7355
7356         if (wc->stage == UPDATE_BACKREF) {
7357                 BUG_ON(wc->shared_level < level);
7358                 if (level < wc->shared_level)
7359                         goto out;
7360
7361                 ret = find_next_key(path, level + 1, &wc->update_progress);
7362                 if (ret > 0)
7363                         wc->update_ref = 0;
7364
7365                 wc->stage = DROP_REFERENCE;
7366                 wc->shared_level = -1;
7367                 path->slots[level] = 0;
7368
7369                 /*
7370                  * check reference count again if the block isn't locked.
7371                  * we should start walking down the tree again if reference
7372                  * count is one.
7373                  */
7374                 if (!path->locks[level]) {
7375                         BUG_ON(level == 0);
7376                         btrfs_tree_lock(eb);
7377                         btrfs_set_lock_blocking(eb);
7378                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7379
7380                         ret = btrfs_lookup_extent_info(trans, root,
7381                                                        eb->start, level, 1,
7382                                                        &wc->refs[level],
7383                                                        &wc->flags[level]);
7384                         if (ret < 0) {
7385                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7386                                 path->locks[level] = 0;
7387                                 return ret;
7388                         }
7389                         BUG_ON(wc->refs[level] == 0);
7390                         if (wc->refs[level] == 1) {
7391                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7392                                 path->locks[level] = 0;
7393                                 return 1;
7394                         }
7395                 }
7396         }
7397
7398         /* wc->stage == DROP_REFERENCE */
7399         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7400
7401         if (wc->refs[level] == 1) {
7402                 if (level == 0) {
7403                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7404                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7405                                                     wc->for_reloc);
7406                         else
7407                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7408                                                     wc->for_reloc);
7409                         BUG_ON(ret); /* -ENOMEM */
7410                 }
7411                 /* make block locked assertion in clean_tree_block happy */
7412                 if (!path->locks[level] &&
7413                     btrfs_header_generation(eb) == trans->transid) {
7414                         btrfs_tree_lock(eb);
7415                         btrfs_set_lock_blocking(eb);
7416                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7417                 }
7418                 clean_tree_block(trans, root, eb);
7419         }
7420
7421         if (eb == root->node) {
7422                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7423                         parent = eb->start;
7424                 else
7425                         BUG_ON(root->root_key.objectid !=
7426                                btrfs_header_owner(eb));
7427         } else {
7428                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7429                         parent = path->nodes[level + 1]->start;
7430                 else
7431                         BUG_ON(root->root_key.objectid !=
7432                                btrfs_header_owner(path->nodes[level + 1]));
7433         }
7434
7435         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7436 out:
7437         wc->refs[level] = 0;
7438         wc->flags[level] = 0;
7439         return 0;
7440 }
7441
7442 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7443                                    struct btrfs_root *root,
7444                                    struct btrfs_path *path,
7445                                    struct walk_control *wc)
7446 {
7447         int level = wc->level;
7448         int lookup_info = 1;
7449         int ret;
7450
7451         while (level >= 0) {
7452                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7453                 if (ret > 0)
7454                         break;
7455
7456                 if (level == 0)
7457                         break;
7458
7459                 if (path->slots[level] >=
7460                     btrfs_header_nritems(path->nodes[level]))
7461                         break;
7462
7463                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7464                 if (ret > 0) {
7465                         path->slots[level]++;
7466                         continue;
7467                 } else if (ret < 0)
7468                         return ret;
7469                 level = wc->level;
7470         }
7471         return 0;
7472 }
7473
7474 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7475                                  struct btrfs_root *root,
7476                                  struct btrfs_path *path,
7477                                  struct walk_control *wc, int max_level)
7478 {
7479         int level = wc->level;
7480         int ret;
7481
7482         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7483         while (level < max_level && path->nodes[level]) {
7484                 wc->level = level;
7485                 if (path->slots[level] + 1 <
7486                     btrfs_header_nritems(path->nodes[level])) {
7487                         path->slots[level]++;
7488                         return 0;
7489                 } else {
7490                         ret = walk_up_proc(trans, root, path, wc);
7491                         if (ret > 0)
7492                                 return 0;
7493
7494                         if (path->locks[level]) {
7495                                 btrfs_tree_unlock_rw(path->nodes[level],
7496                                                      path->locks[level]);
7497                                 path->locks[level] = 0;
7498                         }
7499                         free_extent_buffer(path->nodes[level]);
7500                         path->nodes[level] = NULL;
7501                         level++;
7502                 }
7503         }
7504         return 1;
7505 }
7506
7507 /*
7508  * drop a subvolume tree.
7509  *
7510  * this function traverses the tree freeing any blocks that only
7511  * referenced by the tree.
7512  *
7513  * when a shared tree block is found. this function decreases its
7514  * reference count by one. if update_ref is true, this function
7515  * also make sure backrefs for the shared block and all lower level
7516  * blocks are properly updated.
7517  *
7518  * If called with for_reloc == 0, may exit early with -EAGAIN
7519  */
7520 int btrfs_drop_snapshot(struct btrfs_root *root,
7521                          struct btrfs_block_rsv *block_rsv, int update_ref,
7522                          int for_reloc)
7523 {
7524         struct btrfs_path *path;
7525         struct btrfs_trans_handle *trans;
7526         struct btrfs_root *tree_root = root->fs_info->tree_root;
7527         struct btrfs_root_item *root_item = &root->root_item;
7528         struct walk_control *wc;
7529         struct btrfs_key key;
7530         int err = 0;
7531         int ret;
7532         int level;
7533         bool root_dropped = false;
7534
7535         path = btrfs_alloc_path();
7536         if (!path) {
7537                 err = -ENOMEM;
7538                 goto out;
7539         }
7540
7541         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7542         if (!wc) {
7543                 btrfs_free_path(path);
7544                 err = -ENOMEM;
7545                 goto out;
7546         }
7547
7548         trans = btrfs_start_transaction(tree_root, 0);
7549         if (IS_ERR(trans)) {
7550                 err = PTR_ERR(trans);
7551                 goto out_free;
7552         }
7553
7554         if (block_rsv)
7555                 trans->block_rsv = block_rsv;
7556
7557         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7558                 level = btrfs_header_level(root->node);
7559                 path->nodes[level] = btrfs_lock_root_node(root);
7560                 btrfs_set_lock_blocking(path->nodes[level]);
7561                 path->slots[level] = 0;
7562                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7563                 memset(&wc->update_progress, 0,
7564                        sizeof(wc->update_progress));
7565         } else {
7566                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7567                 memcpy(&wc->update_progress, &key,
7568                        sizeof(wc->update_progress));
7569
7570                 level = root_item->drop_level;
7571                 BUG_ON(level == 0);
7572                 path->lowest_level = level;
7573                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7574                 path->lowest_level = 0;
7575                 if (ret < 0) {
7576                         err = ret;
7577                         goto out_end_trans;
7578                 }
7579                 WARN_ON(ret > 0);
7580
7581                 /*
7582                  * unlock our path, this is safe because only this
7583                  * function is allowed to delete this snapshot
7584                  */
7585                 btrfs_unlock_up_safe(path, 0);
7586
7587                 level = btrfs_header_level(root->node);
7588                 while (1) {
7589                         btrfs_tree_lock(path->nodes[level]);
7590                         btrfs_set_lock_blocking(path->nodes[level]);
7591                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7592
7593                         ret = btrfs_lookup_extent_info(trans, root,
7594                                                 path->nodes[level]->start,
7595                                                 level, 1, &wc->refs[level],
7596                                                 &wc->flags[level]);
7597                         if (ret < 0) {
7598                                 err = ret;
7599                                 goto out_end_trans;
7600                         }
7601                         BUG_ON(wc->refs[level] == 0);
7602
7603                         if (level == root_item->drop_level)
7604                                 break;
7605
7606                         btrfs_tree_unlock(path->nodes[level]);
7607                         path->locks[level] = 0;
7608                         WARN_ON(wc->refs[level] != 1);
7609                         level--;
7610                 }
7611         }
7612
7613         wc->level = level;
7614         wc->shared_level = -1;
7615         wc->stage = DROP_REFERENCE;
7616         wc->update_ref = update_ref;
7617         wc->keep_locks = 0;
7618         wc->for_reloc = for_reloc;
7619         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7620
7621         while (1) {
7622
7623                 ret = walk_down_tree(trans, root, path, wc);
7624                 if (ret < 0) {
7625                         err = ret;
7626                         break;
7627                 }
7628
7629                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7630                 if (ret < 0) {
7631                         err = ret;
7632                         break;
7633                 }
7634
7635                 if (ret > 0) {
7636                         BUG_ON(wc->stage != DROP_REFERENCE);
7637                         break;
7638                 }
7639
7640                 if (wc->stage == DROP_REFERENCE) {
7641                         level = wc->level;
7642                         btrfs_node_key(path->nodes[level],
7643                                        &root_item->drop_progress,
7644                                        path->slots[level]);
7645                         root_item->drop_level = level;
7646                 }
7647
7648                 BUG_ON(wc->level == 0);
7649                 if (btrfs_should_end_transaction(trans, tree_root) ||
7650                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7651                         ret = btrfs_update_root(trans, tree_root,
7652                                                 &root->root_key,
7653                                                 root_item);
7654                         if (ret) {
7655                                 btrfs_abort_transaction(trans, tree_root, ret);
7656                                 err = ret;
7657                                 goto out_end_trans;
7658                         }
7659
7660                         btrfs_end_transaction_throttle(trans, tree_root);
7661                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7662                                 pr_debug("btrfs: drop snapshot early exit\n");
7663                                 err = -EAGAIN;
7664                                 goto out_free;
7665                         }
7666
7667                         trans = btrfs_start_transaction(tree_root, 0);
7668                         if (IS_ERR(trans)) {
7669                                 err = PTR_ERR(trans);
7670                                 goto out_free;
7671                         }
7672                         if (block_rsv)
7673                                 trans->block_rsv = block_rsv;
7674                 }
7675         }
7676         btrfs_release_path(path);
7677         if (err)
7678                 goto out_end_trans;
7679
7680         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7681         if (ret) {
7682                 btrfs_abort_transaction(trans, tree_root, ret);
7683                 goto out_end_trans;
7684         }
7685
7686         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7687                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7688                                       NULL, NULL);
7689                 if (ret < 0) {
7690                         btrfs_abort_transaction(trans, tree_root, ret);
7691                         err = ret;
7692                         goto out_end_trans;
7693                 } else if (ret > 0) {
7694                         /* if we fail to delete the orphan item this time
7695                          * around, it'll get picked up the next time.
7696                          *
7697                          * The most common failure here is just -ENOENT.
7698                          */
7699                         btrfs_del_orphan_item(trans, tree_root,
7700                                               root->root_key.objectid);
7701                 }
7702         }
7703
7704         if (root->in_radix) {
7705                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7706         } else {
7707                 free_extent_buffer(root->node);
7708                 free_extent_buffer(root->commit_root);
7709                 btrfs_put_fs_root(root);
7710         }
7711         root_dropped = true;
7712 out_end_trans:
7713         btrfs_end_transaction_throttle(trans, tree_root);
7714 out_free:
7715         kfree(wc);
7716         btrfs_free_path(path);
7717 out:
7718         /*
7719          * So if we need to stop dropping the snapshot for whatever reason we
7720          * need to make sure to add it back to the dead root list so that we
7721          * keep trying to do the work later.  This also cleans up roots if we
7722          * don't have it in the radix (like when we recover after a power fail
7723          * or unmount) so we don't leak memory.
7724          */
7725         if (!for_reloc && root_dropped == false)
7726                 btrfs_add_dead_root(root);
7727         if (err)
7728                 btrfs_std_error(root->fs_info, err);
7729         return err;
7730 }
7731
7732 /*
7733  * drop subtree rooted at tree block 'node'.
7734  *
7735  * NOTE: this function will unlock and release tree block 'node'
7736  * only used by relocation code
7737  */
7738 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7739                         struct btrfs_root *root,
7740                         struct extent_buffer *node,
7741                         struct extent_buffer *parent)
7742 {
7743         struct btrfs_path *path;
7744         struct walk_control *wc;
7745         int level;
7746         int parent_level;
7747         int ret = 0;
7748         int wret;
7749
7750         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7751
7752         path = btrfs_alloc_path();
7753         if (!path)
7754                 return -ENOMEM;
7755
7756         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7757         if (!wc) {
7758                 btrfs_free_path(path);
7759                 return -ENOMEM;
7760         }
7761
7762         btrfs_assert_tree_locked(parent);
7763         parent_level = btrfs_header_level(parent);
7764         extent_buffer_get(parent);
7765         path->nodes[parent_level] = parent;
7766         path->slots[parent_level] = btrfs_header_nritems(parent);
7767
7768         btrfs_assert_tree_locked(node);
7769         level = btrfs_header_level(node);
7770         path->nodes[level] = node;
7771         path->slots[level] = 0;
7772         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7773
7774         wc->refs[parent_level] = 1;
7775         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7776         wc->level = level;
7777         wc->shared_level = -1;
7778         wc->stage = DROP_REFERENCE;
7779         wc->update_ref = 0;
7780         wc->keep_locks = 1;
7781         wc->for_reloc = 1;
7782         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7783
7784         while (1) {
7785                 wret = walk_down_tree(trans, root, path, wc);
7786                 if (wret < 0) {
7787                         ret = wret;
7788                         break;
7789                 }
7790
7791                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7792                 if (wret < 0)
7793                         ret = wret;
7794                 if (wret != 0)
7795                         break;
7796         }
7797
7798         kfree(wc);
7799         btrfs_free_path(path);
7800         return ret;
7801 }
7802
7803 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7804 {
7805         u64 num_devices;
7806         u64 stripped;
7807
7808         /*
7809          * if restripe for this chunk_type is on pick target profile and
7810          * return, otherwise do the usual balance
7811          */
7812         stripped = get_restripe_target(root->fs_info, flags);
7813         if (stripped)
7814                 return extended_to_chunk(stripped);
7815
7816         /*
7817          * we add in the count of missing devices because we want
7818          * to make sure that any RAID levels on a degraded FS
7819          * continue to be honored.
7820          */
7821         num_devices = root->fs_info->fs_devices->rw_devices +
7822                 root->fs_info->fs_devices->missing_devices;
7823
7824         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7825                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7826                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7827
7828         if (num_devices == 1) {
7829                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7830                 stripped = flags & ~stripped;
7831
7832                 /* turn raid0 into single device chunks */
7833                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7834                         return stripped;
7835
7836                 /* turn mirroring into duplication */
7837                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7838                              BTRFS_BLOCK_GROUP_RAID10))
7839                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7840         } else {
7841                 /* they already had raid on here, just return */
7842                 if (flags & stripped)
7843                         return flags;
7844
7845                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7846                 stripped = flags & ~stripped;
7847
7848                 /* switch duplicated blocks with raid1 */
7849                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7850                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7851
7852                 /* this is drive concat, leave it alone */
7853         }
7854
7855         return flags;
7856 }
7857
7858 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7859 {
7860         struct btrfs_space_info *sinfo = cache->space_info;
7861         u64 num_bytes;
7862         u64 min_allocable_bytes;
7863         int ret = -ENOSPC;
7864
7865
7866         /*
7867          * We need some metadata space and system metadata space for
7868          * allocating chunks in some corner cases until we force to set
7869          * it to be readonly.
7870          */
7871         if ((sinfo->flags &
7872              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7873             !force)
7874                 min_allocable_bytes = 1 * 1024 * 1024;
7875         else
7876                 min_allocable_bytes = 0;
7877
7878         spin_lock(&sinfo->lock);
7879         spin_lock(&cache->lock);
7880
7881         if (cache->ro) {
7882                 ret = 0;
7883                 goto out;
7884         }
7885
7886         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7887                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7888
7889         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7890             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7891             min_allocable_bytes <= sinfo->total_bytes) {
7892                 sinfo->bytes_readonly += num_bytes;
7893                 cache->ro = 1;
7894                 ret = 0;
7895         }
7896 out:
7897         spin_unlock(&cache->lock);
7898         spin_unlock(&sinfo->lock);
7899         return ret;
7900 }
7901
7902 int btrfs_set_block_group_ro(struct btrfs_root *root,
7903                              struct btrfs_block_group_cache *cache)
7904
7905 {
7906         struct btrfs_trans_handle *trans;
7907         u64 alloc_flags;
7908         int ret;
7909
7910         BUG_ON(cache->ro);
7911
7912         trans = btrfs_join_transaction(root);
7913         if (IS_ERR(trans))
7914                 return PTR_ERR(trans);
7915
7916         alloc_flags = update_block_group_flags(root, cache->flags);
7917         if (alloc_flags != cache->flags) {
7918                 ret = do_chunk_alloc(trans, root, alloc_flags,
7919                                      CHUNK_ALLOC_FORCE);
7920                 if (ret < 0)
7921                         goto out;
7922         }
7923
7924         ret = set_block_group_ro(cache, 0);
7925         if (!ret)
7926                 goto out;
7927         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7928         ret = do_chunk_alloc(trans, root, alloc_flags,
7929                              CHUNK_ALLOC_FORCE);
7930         if (ret < 0)
7931                 goto out;
7932         ret = set_block_group_ro(cache, 0);
7933 out:
7934         btrfs_end_transaction(trans, root);
7935         return ret;
7936 }
7937
7938 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7939                             struct btrfs_root *root, u64 type)
7940 {
7941         u64 alloc_flags = get_alloc_profile(root, type);
7942         return do_chunk_alloc(trans, root, alloc_flags,
7943                               CHUNK_ALLOC_FORCE);
7944 }
7945
7946 /*
7947  * helper to account the unused space of all the readonly block group in the
7948  * list. takes mirrors into account.
7949  */
7950 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7951 {
7952         struct btrfs_block_group_cache *block_group;
7953         u64 free_bytes = 0;
7954         int factor;
7955
7956         list_for_each_entry(block_group, groups_list, list) {
7957                 spin_lock(&block_group->lock);
7958
7959                 if (!block_group->ro) {
7960                         spin_unlock(&block_group->lock);
7961                         continue;
7962                 }
7963
7964                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7965                                           BTRFS_BLOCK_GROUP_RAID10 |
7966                                           BTRFS_BLOCK_GROUP_DUP))
7967                         factor = 2;
7968                 else
7969                         factor = 1;
7970
7971                 free_bytes += (block_group->key.offset -
7972                                btrfs_block_group_used(&block_group->item)) *
7973                                factor;
7974
7975                 spin_unlock(&block_group->lock);
7976         }
7977
7978         return free_bytes;
7979 }
7980
7981 /*
7982  * helper to account the unused space of all the readonly block group in the
7983  * space_info. takes mirrors into account.
7984  */
7985 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7986 {
7987         int i;
7988         u64 free_bytes = 0;
7989
7990         spin_lock(&sinfo->lock);
7991
7992         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7993                 if (!list_empty(&sinfo->block_groups[i]))
7994                         free_bytes += __btrfs_get_ro_block_group_free_space(
7995                                                 &sinfo->block_groups[i]);
7996
7997         spin_unlock(&sinfo->lock);
7998
7999         return free_bytes;
8000 }
8001
8002 void btrfs_set_block_group_rw(struct btrfs_root *root,
8003                               struct btrfs_block_group_cache *cache)
8004 {
8005         struct btrfs_space_info *sinfo = cache->space_info;
8006         u64 num_bytes;
8007
8008         BUG_ON(!cache->ro);
8009
8010         spin_lock(&sinfo->lock);
8011         spin_lock(&cache->lock);
8012         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8013                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8014         sinfo->bytes_readonly -= num_bytes;
8015         cache->ro = 0;
8016         spin_unlock(&cache->lock);
8017         spin_unlock(&sinfo->lock);
8018 }
8019
8020 /*
8021  * checks to see if its even possible to relocate this block group.
8022  *
8023  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8024  * ok to go ahead and try.
8025  */
8026 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8027 {
8028         struct btrfs_block_group_cache *block_group;
8029         struct btrfs_space_info *space_info;
8030         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8031         struct btrfs_device *device;
8032         struct btrfs_trans_handle *trans;
8033         u64 min_free;
8034         u64 dev_min = 1;
8035         u64 dev_nr = 0;
8036         u64 target;
8037         int index;
8038         int full = 0;
8039         int ret = 0;
8040
8041         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8042
8043         /* odd, couldn't find the block group, leave it alone */
8044         if (!block_group)
8045                 return -1;
8046
8047         min_free = btrfs_block_group_used(&block_group->item);
8048
8049         /* no bytes used, we're good */
8050         if (!min_free)
8051                 goto out;
8052
8053         space_info = block_group->space_info;
8054         spin_lock(&space_info->lock);
8055
8056         full = space_info->full;
8057
8058         /*
8059          * if this is the last block group we have in this space, we can't
8060          * relocate it unless we're able to allocate a new chunk below.
8061          *
8062          * Otherwise, we need to make sure we have room in the space to handle
8063          * all of the extents from this block group.  If we can, we're good
8064          */
8065         if ((space_info->total_bytes != block_group->key.offset) &&
8066             (space_info->bytes_used + space_info->bytes_reserved +
8067              space_info->bytes_pinned + space_info->bytes_readonly +
8068              min_free < space_info->total_bytes)) {
8069                 spin_unlock(&space_info->lock);
8070                 goto out;
8071         }
8072         spin_unlock(&space_info->lock);
8073
8074         /*
8075          * ok we don't have enough space, but maybe we have free space on our
8076          * devices to allocate new chunks for relocation, so loop through our
8077          * alloc devices and guess if we have enough space.  if this block
8078          * group is going to be restriped, run checks against the target
8079          * profile instead of the current one.
8080          */
8081         ret = -1;
8082
8083         /*
8084          * index:
8085          *      0: raid10
8086          *      1: raid1
8087          *      2: dup
8088          *      3: raid0
8089          *      4: single
8090          */
8091         target = get_restripe_target(root->fs_info, block_group->flags);
8092         if (target) {
8093                 index = __get_raid_index(extended_to_chunk(target));
8094         } else {
8095                 /*
8096                  * this is just a balance, so if we were marked as full
8097                  * we know there is no space for a new chunk
8098                  */
8099                 if (full)
8100                         goto out;
8101
8102                 index = get_block_group_index(block_group);
8103         }
8104
8105         if (index == BTRFS_RAID_RAID10) {
8106                 dev_min = 4;
8107                 /* Divide by 2 */
8108                 min_free >>= 1;
8109         } else if (index == BTRFS_RAID_RAID1) {
8110                 dev_min = 2;
8111         } else if (index == BTRFS_RAID_DUP) {
8112                 /* Multiply by 2 */
8113                 min_free <<= 1;
8114         } else if (index == BTRFS_RAID_RAID0) {
8115                 dev_min = fs_devices->rw_devices;
8116                 do_div(min_free, dev_min);
8117         }
8118
8119         /* We need to do this so that we can look at pending chunks */
8120         trans = btrfs_join_transaction(root);
8121         if (IS_ERR(trans)) {
8122                 ret = PTR_ERR(trans);
8123                 goto out;
8124         }
8125
8126         mutex_lock(&root->fs_info->chunk_mutex);
8127         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8128                 u64 dev_offset;
8129
8130                 /*
8131                  * check to make sure we can actually find a chunk with enough
8132                  * space to fit our block group in.
8133                  */
8134                 if (device->total_bytes > device->bytes_used + min_free &&
8135                     !device->is_tgtdev_for_dev_replace) {
8136                         ret = find_free_dev_extent(trans, device, min_free,
8137                                                    &dev_offset, NULL);
8138                         if (!ret)
8139                                 dev_nr++;
8140
8141                         if (dev_nr >= dev_min)
8142                                 break;
8143
8144                         ret = -1;
8145                 }
8146         }
8147         mutex_unlock(&root->fs_info->chunk_mutex);
8148         btrfs_end_transaction(trans, root);
8149 out:
8150         btrfs_put_block_group(block_group);
8151         return ret;
8152 }
8153
8154 static int find_first_block_group(struct btrfs_root *root,
8155                 struct btrfs_path *path, struct btrfs_key *key)
8156 {
8157         int ret = 0;
8158         struct btrfs_key found_key;
8159         struct extent_buffer *leaf;
8160         int slot;
8161
8162         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8163         if (ret < 0)
8164                 goto out;
8165
8166         while (1) {
8167                 slot = path->slots[0];
8168                 leaf = path->nodes[0];
8169                 if (slot >= btrfs_header_nritems(leaf)) {
8170                         ret = btrfs_next_leaf(root, path);
8171                         if (ret == 0)
8172                                 continue;
8173                         if (ret < 0)
8174                                 goto out;
8175                         break;
8176                 }
8177                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8178
8179                 if (found_key.objectid >= key->objectid &&
8180                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8181                         ret = 0;
8182                         goto out;
8183                 }
8184                 path->slots[0]++;
8185         }
8186 out:
8187         return ret;
8188 }
8189
8190 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8191 {
8192         struct btrfs_block_group_cache *block_group;
8193         u64 last = 0;
8194
8195         while (1) {
8196                 struct inode *inode;
8197
8198                 block_group = btrfs_lookup_first_block_group(info, last);
8199                 while (block_group) {
8200                         spin_lock(&block_group->lock);
8201                         if (block_group->iref)
8202                                 break;
8203                         spin_unlock(&block_group->lock);
8204                         block_group = next_block_group(info->tree_root,
8205                                                        block_group);
8206                 }
8207                 if (!block_group) {
8208                         if (last == 0)
8209                                 break;
8210                         last = 0;
8211                         continue;
8212                 }
8213
8214                 inode = block_group->inode;
8215                 block_group->iref = 0;
8216                 block_group->inode = NULL;
8217                 spin_unlock(&block_group->lock);
8218                 iput(inode);
8219                 last = block_group->key.objectid + block_group->key.offset;
8220                 btrfs_put_block_group(block_group);
8221         }
8222 }
8223
8224 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8225 {
8226         struct btrfs_block_group_cache *block_group;
8227         struct btrfs_space_info *space_info;
8228         struct btrfs_caching_control *caching_ctl;
8229         struct rb_node *n;
8230
8231         down_write(&info->extent_commit_sem);
8232         while (!list_empty(&info->caching_block_groups)) {
8233                 caching_ctl = list_entry(info->caching_block_groups.next,
8234                                          struct btrfs_caching_control, list);
8235                 list_del(&caching_ctl->list);
8236                 put_caching_control(caching_ctl);
8237         }
8238         up_write(&info->extent_commit_sem);
8239
8240         spin_lock(&info->block_group_cache_lock);
8241         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8242                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8243                                        cache_node);
8244                 rb_erase(&block_group->cache_node,
8245                          &info->block_group_cache_tree);
8246                 spin_unlock(&info->block_group_cache_lock);
8247
8248                 down_write(&block_group->space_info->groups_sem);
8249                 list_del(&block_group->list);
8250                 up_write(&block_group->space_info->groups_sem);
8251
8252                 if (block_group->cached == BTRFS_CACHE_STARTED)
8253                         wait_block_group_cache_done(block_group);
8254
8255                 /*
8256                  * We haven't cached this block group, which means we could
8257                  * possibly have excluded extents on this block group.
8258                  */
8259                 if (block_group->cached == BTRFS_CACHE_NO ||
8260                     block_group->cached == BTRFS_CACHE_ERROR)
8261                         free_excluded_extents(info->extent_root, block_group);
8262
8263                 btrfs_remove_free_space_cache(block_group);
8264                 btrfs_put_block_group(block_group);
8265
8266                 spin_lock(&info->block_group_cache_lock);
8267         }
8268         spin_unlock(&info->block_group_cache_lock);
8269
8270         /* now that all the block groups are freed, go through and
8271          * free all the space_info structs.  This is only called during
8272          * the final stages of unmount, and so we know nobody is
8273          * using them.  We call synchronize_rcu() once before we start,
8274          * just to be on the safe side.
8275          */
8276         synchronize_rcu();
8277
8278         release_global_block_rsv(info);
8279
8280         while(!list_empty(&info->space_info)) {
8281                 space_info = list_entry(info->space_info.next,
8282                                         struct btrfs_space_info,
8283                                         list);
8284                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8285                         if (space_info->bytes_pinned > 0 ||
8286                             space_info->bytes_reserved > 0 ||
8287                             space_info->bytes_may_use > 0) {
8288                                 WARN_ON(1);
8289                                 dump_space_info(space_info, 0, 0);
8290                         }
8291                 }
8292                 percpu_counter_destroy(&space_info->total_bytes_pinned);
8293                 list_del(&space_info->list);
8294                 kfree(space_info);
8295         }
8296         return 0;
8297 }
8298
8299 static void __link_block_group(struct btrfs_space_info *space_info,
8300                                struct btrfs_block_group_cache *cache)
8301 {
8302         int index = get_block_group_index(cache);
8303
8304         down_write(&space_info->groups_sem);
8305         list_add_tail(&cache->list, &space_info->block_groups[index]);
8306         up_write(&space_info->groups_sem);
8307 }
8308
8309 int btrfs_read_block_groups(struct btrfs_root *root)
8310 {
8311         struct btrfs_path *path;
8312         int ret;
8313         struct btrfs_block_group_cache *cache;
8314         struct btrfs_fs_info *info = root->fs_info;
8315         struct btrfs_space_info *space_info;
8316         struct btrfs_key key;
8317         struct btrfs_key found_key;
8318         struct extent_buffer *leaf;
8319         int need_clear = 0;
8320         u64 cache_gen;
8321
8322         root = info->extent_root;
8323         key.objectid = 0;
8324         key.offset = 0;
8325         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8326         path = btrfs_alloc_path();
8327         if (!path)
8328                 return -ENOMEM;
8329         path->reada = 1;
8330
8331         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8332         if (btrfs_test_opt(root, SPACE_CACHE) &&
8333             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8334                 need_clear = 1;
8335         if (btrfs_test_opt(root, CLEAR_CACHE))
8336                 need_clear = 1;
8337
8338         while (1) {
8339                 ret = find_first_block_group(root, path, &key);
8340                 if (ret > 0)
8341                         break;
8342                 if (ret != 0)
8343                         goto error;
8344                 leaf = path->nodes[0];
8345                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8346                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8347                 if (!cache) {
8348                         ret = -ENOMEM;
8349                         goto error;
8350                 }
8351                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8352                                                 GFP_NOFS);
8353                 if (!cache->free_space_ctl) {
8354                         kfree(cache);
8355                         ret = -ENOMEM;
8356                         goto error;
8357                 }
8358
8359                 atomic_set(&cache->count, 1);
8360                 spin_lock_init(&cache->lock);
8361                 cache->fs_info = info;
8362                 INIT_LIST_HEAD(&cache->list);
8363                 INIT_LIST_HEAD(&cache->cluster_list);
8364
8365                 if (need_clear) {
8366                         /*
8367                          * When we mount with old space cache, we need to
8368                          * set BTRFS_DC_CLEAR and set dirty flag.
8369                          *
8370                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8371                          *    truncate the old free space cache inode and
8372                          *    setup a new one.
8373                          * b) Setting 'dirty flag' makes sure that we flush
8374                          *    the new space cache info onto disk.
8375                          */
8376                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8377                         if (btrfs_test_opt(root, SPACE_CACHE))
8378                                 cache->dirty = 1;
8379                 }
8380
8381                 read_extent_buffer(leaf, &cache->item,
8382                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8383                                    sizeof(cache->item));
8384                 memcpy(&cache->key, &found_key, sizeof(found_key));
8385
8386                 key.objectid = found_key.objectid + found_key.offset;
8387                 btrfs_release_path(path);
8388                 cache->flags = btrfs_block_group_flags(&cache->item);
8389                 cache->sectorsize = root->sectorsize;
8390                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8391                                                &root->fs_info->mapping_tree,
8392                                                found_key.objectid);
8393                 btrfs_init_free_space_ctl(cache);
8394
8395                 /*
8396                  * We need to exclude the super stripes now so that the space
8397                  * info has super bytes accounted for, otherwise we'll think
8398                  * we have more space than we actually do.
8399                  */
8400                 ret = exclude_super_stripes(root, cache);
8401                 if (ret) {
8402                         /*
8403                          * We may have excluded something, so call this just in
8404                          * case.
8405                          */
8406                         free_excluded_extents(root, cache);
8407                         kfree(cache->free_space_ctl);
8408                         kfree(cache);
8409                         goto error;
8410                 }
8411
8412                 /*
8413                  * check for two cases, either we are full, and therefore
8414                  * don't need to bother with the caching work since we won't
8415                  * find any space, or we are empty, and we can just add all
8416                  * the space in and be done with it.  This saves us _alot_ of
8417                  * time, particularly in the full case.
8418                  */
8419                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8420                         cache->last_byte_to_unpin = (u64)-1;
8421                         cache->cached = BTRFS_CACHE_FINISHED;
8422                         free_excluded_extents(root, cache);
8423                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8424                         cache->last_byte_to_unpin = (u64)-1;
8425                         cache->cached = BTRFS_CACHE_FINISHED;
8426                         add_new_free_space(cache, root->fs_info,
8427                                            found_key.objectid,
8428                                            found_key.objectid +
8429                                            found_key.offset);
8430                         free_excluded_extents(root, cache);
8431                 }
8432
8433                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8434                 if (ret) {
8435                         btrfs_remove_free_space_cache(cache);
8436                         btrfs_put_block_group(cache);
8437                         goto error;
8438                 }
8439
8440                 ret = update_space_info(info, cache->flags, found_key.offset,
8441                                         btrfs_block_group_used(&cache->item),
8442                                         &space_info);
8443                 if (ret) {
8444                         btrfs_remove_free_space_cache(cache);
8445                         spin_lock(&info->block_group_cache_lock);
8446                         rb_erase(&cache->cache_node,
8447                                  &info->block_group_cache_tree);
8448                         spin_unlock(&info->block_group_cache_lock);
8449                         btrfs_put_block_group(cache);
8450                         goto error;
8451                 }
8452
8453                 cache->space_info = space_info;
8454                 spin_lock(&cache->space_info->lock);
8455                 cache->space_info->bytes_readonly += cache->bytes_super;
8456                 spin_unlock(&cache->space_info->lock);
8457
8458                 __link_block_group(space_info, cache);
8459
8460                 set_avail_alloc_bits(root->fs_info, cache->flags);
8461                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8462                         set_block_group_ro(cache, 1);
8463         }
8464
8465         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8466                 if (!(get_alloc_profile(root, space_info->flags) &
8467                       (BTRFS_BLOCK_GROUP_RAID10 |
8468                        BTRFS_BLOCK_GROUP_RAID1 |
8469                        BTRFS_BLOCK_GROUP_RAID5 |
8470                        BTRFS_BLOCK_GROUP_RAID6 |
8471                        BTRFS_BLOCK_GROUP_DUP)))
8472                         continue;
8473                 /*
8474                  * avoid allocating from un-mirrored block group if there are
8475                  * mirrored block groups.
8476                  */
8477                 list_for_each_entry(cache,
8478                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8479                                 list)
8480                         set_block_group_ro(cache, 1);
8481                 list_for_each_entry(cache,
8482                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8483                                 list)
8484                         set_block_group_ro(cache, 1);
8485         }
8486
8487         init_global_block_rsv(info);
8488         ret = 0;
8489 error:
8490         btrfs_free_path(path);
8491         return ret;
8492 }
8493
8494 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8495                                        struct btrfs_root *root)
8496 {
8497         struct btrfs_block_group_cache *block_group, *tmp;
8498         struct btrfs_root *extent_root = root->fs_info->extent_root;
8499         struct btrfs_block_group_item item;
8500         struct btrfs_key key;
8501         int ret = 0;
8502
8503         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8504                                  new_bg_list) {
8505                 list_del_init(&block_group->new_bg_list);
8506
8507                 if (ret)
8508                         continue;
8509
8510                 spin_lock(&block_group->lock);
8511                 memcpy(&item, &block_group->item, sizeof(item));
8512                 memcpy(&key, &block_group->key, sizeof(key));
8513                 spin_unlock(&block_group->lock);
8514
8515                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8516                                         sizeof(item));
8517                 if (ret)
8518                         btrfs_abort_transaction(trans, extent_root, ret);
8519                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8520                                                key.objectid, key.offset);
8521                 if (ret)
8522                         btrfs_abort_transaction(trans, extent_root, ret);
8523         }
8524 }
8525
8526 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8527                            struct btrfs_root *root, u64 bytes_used,
8528                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8529                            u64 size)
8530 {
8531         int ret;
8532         struct btrfs_root *extent_root;
8533         struct btrfs_block_group_cache *cache;
8534
8535         extent_root = root->fs_info->extent_root;
8536
8537         root->fs_info->last_trans_log_full_commit = trans->transid;
8538
8539         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8540         if (!cache)
8541                 return -ENOMEM;
8542         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8543                                         GFP_NOFS);
8544         if (!cache->free_space_ctl) {
8545                 kfree(cache);
8546                 return -ENOMEM;
8547         }
8548
8549         cache->key.objectid = chunk_offset;
8550         cache->key.offset = size;
8551         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8552         cache->sectorsize = root->sectorsize;
8553         cache->fs_info = root->fs_info;
8554         cache->full_stripe_len = btrfs_full_stripe_len(root,
8555                                                &root->fs_info->mapping_tree,
8556                                                chunk_offset);
8557
8558         atomic_set(&cache->count, 1);
8559         spin_lock_init(&cache->lock);
8560         INIT_LIST_HEAD(&cache->list);
8561         INIT_LIST_HEAD(&cache->cluster_list);
8562         INIT_LIST_HEAD(&cache->new_bg_list);
8563
8564         btrfs_init_free_space_ctl(cache);
8565
8566         btrfs_set_block_group_used(&cache->item, bytes_used);
8567         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8568         cache->flags = type;
8569         btrfs_set_block_group_flags(&cache->item, type);
8570
8571         cache->last_byte_to_unpin = (u64)-1;
8572         cache->cached = BTRFS_CACHE_FINISHED;
8573         ret = exclude_super_stripes(root, cache);
8574         if (ret) {
8575                 /*
8576                  * We may have excluded something, so call this just in
8577                  * case.
8578                  */
8579                 free_excluded_extents(root, cache);
8580                 kfree(cache->free_space_ctl);
8581                 kfree(cache);
8582                 return ret;
8583         }
8584
8585         add_new_free_space(cache, root->fs_info, chunk_offset,
8586                            chunk_offset + size);
8587
8588         free_excluded_extents(root, cache);
8589
8590         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8591         if (ret) {
8592                 btrfs_remove_free_space_cache(cache);
8593                 btrfs_put_block_group(cache);
8594                 return ret;
8595         }
8596
8597         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8598                                 &cache->space_info);
8599         if (ret) {
8600                 btrfs_remove_free_space_cache(cache);
8601                 spin_lock(&root->fs_info->block_group_cache_lock);
8602                 rb_erase(&cache->cache_node,
8603                          &root->fs_info->block_group_cache_tree);
8604                 spin_unlock(&root->fs_info->block_group_cache_lock);
8605                 btrfs_put_block_group(cache);
8606                 return ret;
8607         }
8608         update_global_block_rsv(root->fs_info);
8609
8610         spin_lock(&cache->space_info->lock);
8611         cache->space_info->bytes_readonly += cache->bytes_super;
8612         spin_unlock(&cache->space_info->lock);
8613
8614         __link_block_group(cache->space_info, cache);
8615
8616         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8617
8618         set_avail_alloc_bits(extent_root->fs_info, type);
8619
8620         return 0;
8621 }
8622
8623 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8624 {
8625         u64 extra_flags = chunk_to_extended(flags) &
8626                                 BTRFS_EXTENDED_PROFILE_MASK;
8627
8628         write_seqlock(&fs_info->profiles_lock);
8629         if (flags & BTRFS_BLOCK_GROUP_DATA)
8630                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8631         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8632                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8633         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8634                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8635         write_sequnlock(&fs_info->profiles_lock);
8636 }
8637
8638 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8639                              struct btrfs_root *root, u64 group_start)
8640 {
8641         struct btrfs_path *path;
8642         struct btrfs_block_group_cache *block_group;
8643         struct btrfs_free_cluster *cluster;
8644         struct btrfs_root *tree_root = root->fs_info->tree_root;
8645         struct btrfs_key key;
8646         struct inode *inode;
8647         int ret;
8648         int index;
8649         int factor;
8650
8651         root = root->fs_info->extent_root;
8652
8653         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8654         BUG_ON(!block_group);
8655         BUG_ON(!block_group->ro);
8656
8657         /*
8658          * Free the reserved super bytes from this block group before
8659          * remove it.
8660          */
8661         free_excluded_extents(root, block_group);
8662
8663         memcpy(&key, &block_group->key, sizeof(key));
8664         index = get_block_group_index(block_group);
8665         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8666                                   BTRFS_BLOCK_GROUP_RAID1 |
8667                                   BTRFS_BLOCK_GROUP_RAID10))
8668                 factor = 2;
8669         else
8670                 factor = 1;
8671
8672         /* make sure this block group isn't part of an allocation cluster */
8673         cluster = &root->fs_info->data_alloc_cluster;
8674         spin_lock(&cluster->refill_lock);
8675         btrfs_return_cluster_to_free_space(block_group, cluster);
8676         spin_unlock(&cluster->refill_lock);
8677
8678         /*
8679          * make sure this block group isn't part of a metadata
8680          * allocation cluster
8681          */
8682         cluster = &root->fs_info->meta_alloc_cluster;
8683         spin_lock(&cluster->refill_lock);
8684         btrfs_return_cluster_to_free_space(block_group, cluster);
8685         spin_unlock(&cluster->refill_lock);
8686
8687         path = btrfs_alloc_path();
8688         if (!path) {
8689                 ret = -ENOMEM;
8690                 goto out;
8691         }
8692
8693         inode = lookup_free_space_inode(tree_root, block_group, path);
8694         if (!IS_ERR(inode)) {
8695                 ret = btrfs_orphan_add(trans, inode);
8696                 if (ret) {
8697                         btrfs_add_delayed_iput(inode);
8698                         goto out;
8699                 }
8700                 clear_nlink(inode);
8701                 /* One for the block groups ref */
8702                 spin_lock(&block_group->lock);
8703                 if (block_group->iref) {
8704                         block_group->iref = 0;
8705                         block_group->inode = NULL;
8706                         spin_unlock(&block_group->lock);
8707                         iput(inode);
8708                 } else {
8709                         spin_unlock(&block_group->lock);
8710                 }
8711                 /* One for our lookup ref */
8712                 btrfs_add_delayed_iput(inode);
8713         }
8714
8715         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8716         key.offset = block_group->key.objectid;
8717         key.type = 0;
8718
8719         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8720         if (ret < 0)
8721                 goto out;
8722         if (ret > 0)
8723                 btrfs_release_path(path);
8724         if (ret == 0) {
8725                 ret = btrfs_del_item(trans, tree_root, path);
8726                 if (ret)
8727                         goto out;
8728                 btrfs_release_path(path);
8729         }
8730
8731         spin_lock(&root->fs_info->block_group_cache_lock);
8732         rb_erase(&block_group->cache_node,
8733                  &root->fs_info->block_group_cache_tree);
8734
8735         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8736                 root->fs_info->first_logical_byte = (u64)-1;
8737         spin_unlock(&root->fs_info->block_group_cache_lock);
8738
8739         down_write(&block_group->space_info->groups_sem);
8740         /*
8741          * we must use list_del_init so people can check to see if they
8742          * are still on the list after taking the semaphore
8743          */
8744         list_del_init(&block_group->list);
8745         if (list_empty(&block_group->space_info->block_groups[index]))
8746                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8747         up_write(&block_group->space_info->groups_sem);
8748
8749         if (block_group->cached == BTRFS_CACHE_STARTED)
8750                 wait_block_group_cache_done(block_group);
8751
8752         btrfs_remove_free_space_cache(block_group);
8753
8754         spin_lock(&block_group->space_info->lock);
8755         block_group->space_info->total_bytes -= block_group->key.offset;
8756         block_group->space_info->bytes_readonly -= block_group->key.offset;
8757         block_group->space_info->disk_total -= block_group->key.offset * factor;
8758         spin_unlock(&block_group->space_info->lock);
8759
8760         memcpy(&key, &block_group->key, sizeof(key));
8761
8762         btrfs_clear_space_info_full(root->fs_info);
8763
8764         btrfs_put_block_group(block_group);
8765         btrfs_put_block_group(block_group);
8766
8767         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8768         if (ret > 0)
8769                 ret = -EIO;
8770         if (ret < 0)
8771                 goto out;
8772
8773         ret = btrfs_del_item(trans, root, path);
8774 out:
8775         btrfs_free_path(path);
8776         return ret;
8777 }
8778
8779 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8780 {
8781         struct btrfs_space_info *space_info;
8782         struct btrfs_super_block *disk_super;
8783         u64 features;
8784         u64 flags;
8785         int mixed = 0;
8786         int ret;
8787
8788         disk_super = fs_info->super_copy;
8789         if (!btrfs_super_root(disk_super))
8790                 return 1;
8791
8792         features = btrfs_super_incompat_flags(disk_super);
8793         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8794                 mixed = 1;
8795
8796         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8797         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8798         if (ret)
8799                 goto out;
8800
8801         if (mixed) {
8802                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8803                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8804         } else {
8805                 flags = BTRFS_BLOCK_GROUP_METADATA;
8806                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8807                 if (ret)
8808                         goto out;
8809
8810                 flags = BTRFS_BLOCK_GROUP_DATA;
8811                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8812         }
8813 out:
8814         return ret;
8815 }
8816
8817 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8818 {
8819         return unpin_extent_range(root, start, end);
8820 }
8821
8822 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8823                                u64 num_bytes, u64 *actual_bytes)
8824 {
8825         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8826 }
8827
8828 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8829 {
8830         struct btrfs_fs_info *fs_info = root->fs_info;
8831         struct btrfs_block_group_cache *cache = NULL;
8832         u64 group_trimmed;
8833         u64 start;
8834         u64 end;
8835         u64 trimmed = 0;
8836         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8837         int ret = 0;
8838
8839         /*
8840          * try to trim all FS space, our block group may start from non-zero.
8841          */
8842         if (range->len == total_bytes)
8843                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8844         else
8845                 cache = btrfs_lookup_block_group(fs_info, range->start);
8846
8847         while (cache) {
8848                 if (cache->key.objectid >= (range->start + range->len)) {
8849                         btrfs_put_block_group(cache);
8850                         break;
8851                 }
8852
8853                 start = max(range->start, cache->key.objectid);
8854                 end = min(range->start + range->len,
8855                                 cache->key.objectid + cache->key.offset);
8856
8857                 if (end - start >= range->minlen) {
8858                         if (!block_group_cache_done(cache)) {
8859                                 ret = cache_block_group(cache, 0);
8860                                 if (ret) {
8861                                         btrfs_put_block_group(cache);
8862                                         break;
8863                                 }
8864                                 ret = wait_block_group_cache_done(cache);
8865                                 if (ret) {
8866                                         btrfs_put_block_group(cache);
8867                                         break;
8868                                 }
8869                         }
8870                         ret = btrfs_trim_block_group(cache,
8871                                                      &group_trimmed,
8872                                                      start,
8873                                                      end,
8874                                                      range->minlen);
8875
8876                         trimmed += group_trimmed;
8877                         if (ret) {
8878                                 btrfs_put_block_group(cache);
8879                                 break;
8880                         }
8881                 }
8882
8883                 cache = next_block_group(fs_info->tree_root, cache);
8884         }
8885
8886         range->len = trimmed;
8887         return ret;
8888 }