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 "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36
  37 #undef SCRAMBLE_DELAYED_REFS
  38
  39 /*
  40  * control flags for do_chunk_alloc's force field
  41  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  42  * if we really need one.
  43  *
  44  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  45  * if we have very few chunks already allocated.  This is
  46  * used as part of the clustering code to help make sure
  47  * we have a good pool of storage to cluster in, without
  48  * filling the FS with empty chunks
  49  *
  50  * CHUNK_ALLOC_FORCE means it must try to allocate one
  51  *
  52  */
  53 enum {
  54         CHUNK_ALLOC_NO_FORCE = 0,
  55         CHUNK_ALLOC_LIMITED = 1,
  56         CHUNK_ALLOC_FORCE = 2,
  57 };
  58
  59 /*
  60  * Control how reservations are dealt with.
  61  *
  62  * RESERVE_FREE - freeing a reservation.
  63  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  64  *   ENOSPC accounting
  65  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  66  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  67  */
  68 enum {
  69         RESERVE_FREE = 0,
  70         RESERVE_ALLOC = 1,
  71         RESERVE_ALLOC_NO_ACCOUNT = 2,
  72 };
  73
  74 static int update_block_group(struct btrfs_trans_handle *trans,
  75                               struct btrfs_root *root,
  76                               u64 bytenr, u64 num_bytes, int alloc);
  77 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  78                                 struct btrfs_root *root,
  79                                 u64 bytenr, u64 num_bytes, u64 parent,
  80                                 u64 root_objectid, u64 owner_objectid,
  81                                 u64 owner_offset, int refs_to_drop,
  82                                 struct btrfs_delayed_extent_op *extra_op);
  83 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  84                                     struct extent_buffer *leaf,
  85                                     struct btrfs_extent_item *ei);
  86 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  87                                       struct btrfs_root *root,
  88                                       u64 parent, u64 root_objectid,
  89                                       u64 flags, u64 owner, u64 offset,
  90                                       struct btrfs_key *ins, int ref_mod);
  91 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  92                                      struct btrfs_root *root,
  93                                      u64 parent, u64 root_objectid,
  94                                      u64 flags, struct btrfs_disk_key *key,
  95                                      int level, struct btrfs_key *ins);
  96 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  97                           struct btrfs_root *extent_root, u64 alloc_bytes,
  98                           u64 flags, int force);
  99 static int find_next_key(struct btrfs_path *path, int level,
 100                          struct btrfs_key *key);
 101 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 102                             int dump_block_groups);
 103 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 104                                        u64 num_bytes, int reserve);
 105
 106 static noinline int
 107 block_group_cache_done(struct btrfs_block_group_cache *cache)
 108 {
 109         smp_mb();
 110         return cache->cached == BTRFS_CACHE_FINISHED;
 111 }
 112
 113 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 114 {
 115         return (cache->flags & bits) == bits;
 116 }
 117
 118 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 119 {
 120         atomic_inc(&cache->count);
 121 }
 122
 123 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 124 {
 125         if (atomic_dec_and_test(&cache->count)) {
 126                 WARN_ON(cache->pinned > 0);
 127                 WARN_ON(cache->reserved > 0);
 128                 kfree(cache->free_space_ctl);
 129                 kfree(cache);
 130         }
 131 }
 132
 133 /*
 134  * this adds the block group to the fs_info rb tree for the block group
 135  * cache
 136  */
 137 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 138                                 struct btrfs_block_group_cache *block_group)
 139 {
 140         struct rb_node **p;
 141         struct rb_node *parent = NULL;
 142         struct btrfs_block_group_cache *cache;
 143
 144         spin_lock(&info->block_group_cache_lock);
 145         p = &info->block_group_cache_tree.rb_node;
 146
 147         while (*p) {
 148                 parent = *p;
 149                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 150                                  cache_node);
 151                 if (block_group->key.objectid < cache->key.objectid) {
 152                         p = &(*p)->rb_left;
 153                 } else if (block_group->key.objectid > cache->key.objectid) {
 154                         p = &(*p)->rb_right;
 155                 } else {
 156                         spin_unlock(&info->block_group_cache_lock);
 157                         return -EEXIST;
 158                 }
 159         }
 160
 161         rb_link_node(&block_group->cache_node, parent, p);
 162         rb_insert_color(&block_group->cache_node,
 163                         &info->block_group_cache_tree);
 164         spin_unlock(&info->block_group_cache_lock);
 165
 166         return 0;
 167 }
 168
 169 /*
 170  * This will return the block group at or after bytenr if contains is 0, else
 171  * it will return the block group that contains the bytenr
 172  */
 173 static struct btrfs_block_group_cache *
 174 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 175                               int contains)
 176 {
 177         struct btrfs_block_group_cache *cache, *ret = NULL;
 178         struct rb_node *n;
 179         u64 end, start;
 180
 181         spin_lock(&info->block_group_cache_lock);
 182         n = info->block_group_cache_tree.rb_node;
 183
 184         while (n) {
 185                 cache = rb_entry(n, struct btrfs_block_group_cache,
 186                                  cache_node);
 187                 end = cache->key.objectid + cache->key.offset - 1;
 188                 start = cache->key.objectid;
 189
 190                 if (bytenr < start) {
 191                         if (!contains && (!ret || start < ret->key.objectid))
 192                                 ret = cache;
 193                         n = n->rb_left;
 194                 } else if (bytenr > start) {
 195                         if (contains && bytenr <= end) {
 196                                 ret = cache;
 197                                 break;
 198                         }
 199                         n = n->rb_right;
 200                 } else {
 201                         ret = cache;
 202                         break;
 203                 }
 204         }
 205         if (ret)
 206                 btrfs_get_block_group(ret);
 207         spin_unlock(&info->block_group_cache_lock);
 208
 209         return ret;
 210 }
 211
 212 static int add_excluded_extent(struct btrfs_root *root,
 213                                u64 start, u64 num_bytes)
 214 {
 215         u64 end = start + num_bytes - 1;
 216         set_extent_bits(&root->fs_info->freed_extents[0],
 217                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 218         set_extent_bits(&root->fs_info->freed_extents[1],
 219                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 220         return 0;
 221 }
 222
 223 static void free_excluded_extents(struct btrfs_root *root,
 224                                   struct btrfs_block_group_cache *cache)
 225 {
 226         u64 start, end;
 227
 228         start = cache->key.objectid;
 229         end = start + cache->key.offset - 1;
 230
 231         clear_extent_bits(&root->fs_info->freed_extents[0],
 232                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 233         clear_extent_bits(&root->fs_info->freed_extents[1],
 234                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 235 }
 236
 237 static int exclude_super_stripes(struct btrfs_root *root,
 238                                  struct btrfs_block_group_cache *cache)
 239 {
 240         u64 bytenr;
 241         u64 *logical;
 242         int stripe_len;
 243         int i, nr, ret;
 244
 245         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 246                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 247                 cache->bytes_super += stripe_len;
 248                 ret = add_excluded_extent(root, cache->key.objectid,
 249                                           stripe_len);
 250                 BUG_ON(ret); /* -ENOMEM */
 251         }
 252
 253         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 254                 bytenr = btrfs_sb_offset(i);
 255                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 256                                        cache->key.objectid, bytenr,
 257                                        0, &logical, &nr, &stripe_len);
 258                 BUG_ON(ret); /* -ENOMEM */
 259
 260                 while (nr--) {
 261                         cache->bytes_super += stripe_len;
 262                         ret = add_excluded_extent(root, logical[nr],
 263                                                   stripe_len);
 264                         BUG_ON(ret); /* -ENOMEM */
 265                 }
 266
 267                 kfree(logical);
 268         }
 269         return 0;
 270 }
 271
 272 static struct btrfs_caching_control *
 273 get_caching_control(struct btrfs_block_group_cache *cache)
 274 {
 275         struct btrfs_caching_control *ctl;
 276
 277         spin_lock(&cache->lock);
 278         if (cache->cached != BTRFS_CACHE_STARTED) {
 279                 spin_unlock(&cache->lock);
 280                 return NULL;
 281         }
 282
 283         /* We're loading it the fast way, so we don't have a caching_ctl. */
 284         if (!cache->caching_ctl) {
 285                 spin_unlock(&cache->lock);
 286                 return NULL;
 287         }
 288
 289         ctl = cache->caching_ctl;
 290         atomic_inc(&ctl->count);
 291         spin_unlock(&cache->lock);
 292         return ctl;
 293 }
 294
 295 static void put_caching_control(struct btrfs_caching_control *ctl)
 296 {
 297         if (atomic_dec_and_test(&ctl->count))
 298                 kfree(ctl);
 299 }
 300
 301 /*
 302  * this is only called by cache_block_group, since we could have freed extents
 303  * we need to check the pinned_extents for any extents that can't be used yet
 304  * since their free space will be released as soon as the transaction commits.
 305  */
 306 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 307                               struct btrfs_fs_info *info, u64 start, u64 end)
 308 {
 309         u64 extent_start, extent_end, size, total_added = 0;
 310         int ret;
 311
 312         while (start < end) {
 313                 ret = find_first_extent_bit(info->pinned_extents, start,
 314                                             &extent_start, &extent_end,
 315                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 316                 if (ret)
 317                         break;
 318
 319                 if (extent_start <= start) {
 320                         start = extent_end + 1;
 321                 } else if (extent_start > start && extent_start < end) {
 322                         size = extent_start - start;
 323                         total_added += size;
 324                         ret = btrfs_add_free_space(block_group, start,
 325                                                    size);
 326                         BUG_ON(ret); /* -ENOMEM or logic error */
 327                         start = extent_end + 1;
 328                 } else {
 329                         break;
 330                 }
 331         }
 332
 333         if (start < end) {
 334                 size = end - start;
 335                 total_added += size;
 336                 ret = btrfs_add_free_space(block_group, start, size);
 337                 BUG_ON(ret); /* -ENOMEM or logic error */
 338         }
 339
 340         return total_added;
 341 }
 342
 343 static noinline void caching_thread(struct btrfs_work *work)
 344 {
 345         struct btrfs_block_group_cache *block_group;
 346         struct btrfs_fs_info *fs_info;
 347         struct btrfs_caching_control *caching_ctl;
 348         struct btrfs_root *extent_root;
 349         struct btrfs_path *path;
 350         struct extent_buffer *leaf;
 351         struct btrfs_key key;
 352         u64 total_found = 0;
 353         u64 last = 0;
 354         u32 nritems;
 355         int ret = 0;
 356
 357         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 358         block_group = caching_ctl->block_group;
 359         fs_info = block_group->fs_info;
 360         extent_root = fs_info->extent_root;
 361
 362         path = btrfs_alloc_path();
 363         if (!path)
 364                 goto out;
 365
 366         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 367
 368         /*
 369          * We don't want to deadlock with somebody trying to allocate a new
 370          * extent for the extent root while also trying to search the extent
 371          * root to add free space.  So we skip locking and search the commit
 372          * root, since its read-only
 373          */
 374         path->skip_locking = 1;
 375         path->search_commit_root = 1;
 376         path->reada = 1;
 377
 378         key.objectid = last;
 379         key.offset = 0;
 380         key.type = BTRFS_EXTENT_ITEM_KEY;
 381 again:
 382         mutex_lock(&caching_ctl->mutex);
 383         /* need to make sure the commit_root doesn't disappear */
 384         down_read(&fs_info->extent_commit_sem);
 385
 386         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 387         if (ret < 0)
 388                 goto err;
 389
 390         leaf = path->nodes[0];
 391         nritems = btrfs_header_nritems(leaf);
 392
 393         while (1) {
 394                 if (btrfs_fs_closing(fs_info) > 1) {
 395                         last = (u64)-1;
 396                         break;
 397                 }
 398
 399                 if (path->slots[0] < nritems) {
 400                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 401                 } else {
 402                         ret = find_next_key(path, 0, &key);
 403                         if (ret)
 404                                 break;
 405
 406                         if (need_resched() ||
 407                             btrfs_next_leaf(extent_root, path)) {
 408                                 caching_ctl->progress = last;
 409                                 btrfs_release_path(path);
 410                                 up_read(&fs_info->extent_commit_sem);
 411                                 mutex_unlock(&caching_ctl->mutex);
 412                                 cond_resched();
 413                                 goto again;
 414                         }
 415                         leaf = path->nodes[0];
 416                         nritems = btrfs_header_nritems(leaf);
 417                         continue;
 418                 }
 419
 420                 if (key.objectid < block_group->key.objectid) {
 421                         path->slots[0]++;
 422                         continue;
 423                 }
 424
 425                 if (key.objectid >= block_group->key.objectid +
 426                     block_group->key.offset)
 427                         break;
 428
 429                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 430                         total_found += add_new_free_space(block_group,
 431                                                           fs_info, last,
 432                                                           key.objectid);
 433                         last = key.objectid + key.offset;
 434
 435                         if (total_found > (1024 * 1024 * 2)) {
 436                                 total_found = 0;
 437                                 wake_up(&caching_ctl->wait);
 438                         }
 439                 }
 440                 path->slots[0]++;
 441         }
 442         ret = 0;
 443
 444         total_found += add_new_free_space(block_group, fs_info, last,
 445                                           block_group->key.objectid +
 446                                           block_group->key.offset);
 447         caching_ctl->progress = (u64)-1;
 448
 449         spin_lock(&block_group->lock);
 450         block_group->caching_ctl = NULL;
 451         block_group->cached = BTRFS_CACHE_FINISHED;
 452         spin_unlock(&block_group->lock);
 453
 454 err:
 455         btrfs_free_path(path);
 456         up_read(&fs_info->extent_commit_sem);
 457
 458         free_excluded_extents(extent_root, block_group);
 459
 460         mutex_unlock(&caching_ctl->mutex);
 461 out:
 462         wake_up(&caching_ctl->wait);
 463
 464         put_caching_control(caching_ctl);
 465         btrfs_put_block_group(block_group);
 466 }
 467
 468 static int cache_block_group(struct btrfs_block_group_cache *cache,
 469                              struct btrfs_trans_handle *trans,
 470                              struct btrfs_root *root,
 471                              int load_cache_only)
 472 {
 473         DEFINE_WAIT(wait);
 474         struct btrfs_fs_info *fs_info = cache->fs_info;
 475         struct btrfs_caching_control *caching_ctl;
 476         int ret = 0;
 477
 478         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 479         if (!caching_ctl)
 480                 return -ENOMEM;
 481
 482         INIT_LIST_HEAD(&caching_ctl->list);
 483         mutex_init(&caching_ctl->mutex);
 484         init_waitqueue_head(&caching_ctl->wait);
 485         caching_ctl->block_group = cache;
 486         caching_ctl->progress = cache->key.objectid;
 487         atomic_set(&caching_ctl->count, 1);
 488         caching_ctl->work.func = caching_thread;
 489
 490         spin_lock(&cache->lock);
 491         /*
 492          * This should be a rare occasion, but this could happen I think in the
 493          * case where one thread starts to load the space cache info, and then
 494          * some other thread starts a transaction commit which tries to do an
 495          * allocation while the other thread is still loading the space cache
 496          * info.  The previous loop should have kept us from choosing this block
 497          * group, but if we've moved to the state where we will wait on caching
 498          * block groups we need to first check if we're doing a fast load here,
 499          * so we can wait for it to finish, otherwise we could end up allocating
 500          * from a block group who's cache gets evicted for one reason or
 501          * another.
 502          */
 503         while (cache->cached == BTRFS_CACHE_FAST) {
 504                 struct btrfs_caching_control *ctl;
 505
 506                 ctl = cache->caching_ctl;
 507                 atomic_inc(&ctl->count);
 508                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 509                 spin_unlock(&cache->lock);
 510
 511                 schedule();
 512
 513                 finish_wait(&ctl->wait, &wait);
 514                 put_caching_control(ctl);
 515                 spin_lock(&cache->lock);
 516         }
 517
 518         if (cache->cached != BTRFS_CACHE_NO) {
 519                 spin_unlock(&cache->lock);
 520                 kfree(caching_ctl);
 521                 return 0;
 522         }
 523         WARN_ON(cache->caching_ctl);
 524         cache->caching_ctl = caching_ctl;
 525         cache->cached = BTRFS_CACHE_FAST;
 526         spin_unlock(&cache->lock);
 527
 528         /*
 529          * We can't do the read from on-disk cache during a commit since we need
 530          * to have the normal tree locking.  Also if we are currently trying to
 531          * allocate blocks for the tree root we can't do the fast caching since
 532          * we likely hold important locks.
 533          */
 534         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 535                 ret = load_free_space_cache(fs_info, cache);
 536
 537                 spin_lock(&cache->lock);
 538                 if (ret == 1) {
 539                         cache->caching_ctl = NULL;
 540                         cache->cached = BTRFS_CACHE_FINISHED;
 541                         cache->last_byte_to_unpin = (u64)-1;
 542                 } else {
 543                         if (load_cache_only) {
 544                                 cache->caching_ctl = NULL;
 545                                 cache->cached = BTRFS_CACHE_NO;
 546                         } else {
 547                                 cache->cached = BTRFS_CACHE_STARTED;
 548                         }
 549                 }
 550                 spin_unlock(&cache->lock);
 551                 wake_up(&caching_ctl->wait);
 552                 if (ret == 1) {
 553                         put_caching_control(caching_ctl);
 554                         free_excluded_extents(fs_info->extent_root, cache);
 555                         return 0;
 556                 }
 557         } else {
 558                 /*
 559                  * We are not going to do the fast caching, set cached to the
 560                  * appropriate value and wakeup any waiters.
 561                  */
 562                 spin_lock(&cache->lock);
 563                 if (load_cache_only) {
 564                         cache->caching_ctl = NULL;
 565                         cache->cached = BTRFS_CACHE_NO;
 566                 } else {
 567                         cache->cached = BTRFS_CACHE_STARTED;
 568                 }
 569                 spin_unlock(&cache->lock);
 570                 wake_up(&caching_ctl->wait);
 571         }
 572
 573         if (load_cache_only) {
 574                 put_caching_control(caching_ctl);
 575                 return 0;
 576         }
 577
 578         down_write(&fs_info->extent_commit_sem);
 579         atomic_inc(&caching_ctl->count);
 580         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 581         up_write(&fs_info->extent_commit_sem);
 582
 583         btrfs_get_block_group(cache);
 584
 585         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 586
 587         return ret;
 588 }
 589
 590 /*
 591  * return the block group that starts at or after bytenr
 592  */
 593 static struct btrfs_block_group_cache *
 594 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 595 {
 596         struct btrfs_block_group_cache *cache;
 597
 598         cache = block_group_cache_tree_search(info, bytenr, 0);
 599
 600         return cache;
 601 }
 602
 603 /*
 604  * return the block group that contains the given bytenr
 605  */
 606 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 607                                                  struct btrfs_fs_info *info,
 608                                                  u64 bytenr)
 609 {
 610         struct btrfs_block_group_cache *cache;
 611
 612         cache = block_group_cache_tree_search(info, bytenr, 1);
 613
 614         return cache;
 615 }
 616
 617 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 618                                                   u64 flags)
 619 {
 620         struct list_head *head = &info->space_info;
 621         struct btrfs_space_info *found;
 622
 623         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 624
 625         rcu_read_lock();
 626         list_for_each_entry_rcu(found, head, list) {
 627                 if (found->flags & flags) {
 628                         rcu_read_unlock();
 629                         return found;
 630                 }
 631         }
 632         rcu_read_unlock();
 633         return NULL;
 634 }
 635
 636 /*
 637  * after adding space to the filesystem, we need to clear the full flags
 638  * on all the space infos.
 639  */
 640 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 641 {
 642         struct list_head *head = &info->space_info;
 643         struct btrfs_space_info *found;
 644
 645         rcu_read_lock();
 646         list_for_each_entry_rcu(found, head, list)
 647                 found->full = 0;
 648         rcu_read_unlock();
 649 }
 650
 651 static u64 div_factor(u64 num, int factor)
 652 {
 653         if (factor == 10)
 654                 return num;
 655         num *= factor;
 656         do_div(num, 10);
 657         return num;
 658 }
 659
 660 static u64 div_factor_fine(u64 num, int factor)
 661 {
 662         if (factor == 100)
 663                 return num;
 664         num *= factor;
 665         do_div(num, 100);
 666         return num;
 667 }
 668
 669 u64 btrfs_find_block_group(struct btrfs_root *root,
 670                            u64 search_start, u64 search_hint, int owner)
 671 {
 672         struct btrfs_block_group_cache *cache;
 673         u64 used;
 674         u64 last = max(search_hint, search_start);
 675         u64 group_start = 0;
 676         int full_search = 0;
 677         int factor = 9;
 678         int wrapped = 0;
 679 again:
 680         while (1) {
 681                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 682                 if (!cache)
 683                         break;
 684
 685                 spin_lock(&cache->lock);
 686                 last = cache->key.objectid + cache->key.offset;
 687                 used = btrfs_block_group_used(&cache->item);
 688
 689                 if ((full_search || !cache->ro) &&
 690                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 691                         if (used + cache->pinned + cache->reserved <
 692                             div_factor(cache->key.offset, factor)) {
 693                                 group_start = cache->key.objectid;
 694                                 spin_unlock(&cache->lock);
 695                                 btrfs_put_block_group(cache);
 696                                 goto found;
 697                         }
 698                 }
 699                 spin_unlock(&cache->lock);
 700                 btrfs_put_block_group(cache);
 701                 cond_resched();
 702         }
 703         if (!wrapped) {
 704                 last = search_start;
 705                 wrapped = 1;
 706                 goto again;
 707         }
 708         if (!full_search && factor < 10) {
 709                 last = search_start;
 710                 full_search = 1;
 711                 factor = 10;
 712                 goto again;
 713         }
 714 found:
 715         return group_start;
 716 }
 717
 718 /* simple helper to search for an existing extent at a given offset */
 719 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 720 {
 721         int ret;
 722         struct btrfs_key key;
 723         struct btrfs_path *path;
 724
 725         path = btrfs_alloc_path();
 726         if (!path)
 727                 return -ENOMEM;
 728
 729         key.objectid = start;
 730         key.offset = len;
 731         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 732         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 733                                 0, 0);
 734         btrfs_free_path(path);
 735         return ret;
 736 }
 737
 738 /*
 739  * helper function to lookup reference count and flags of extent.
 740  *
 741  * the head node for delayed ref is used to store the sum of all the
 742  * reference count modifications queued up in the rbtree. the head
 743  * node may also store the extent flags to set. This way you can check
 744  * to see what the reference count and extent flags would be if all of
 745  * the delayed refs are not processed.
 746  */
 747 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 748                              struct btrfs_root *root, u64 bytenr,
 749                              u64 num_bytes, u64 *refs, u64 *flags)
 750 {
 751         struct btrfs_delayed_ref_head *head;
 752         struct btrfs_delayed_ref_root *delayed_refs;
 753         struct btrfs_path *path;
 754         struct btrfs_extent_item *ei;
 755         struct extent_buffer *leaf;
 756         struct btrfs_key key;
 757         u32 item_size;
 758         u64 num_refs;
 759         u64 extent_flags;
 760         int ret;
 761
 762         path = btrfs_alloc_path();
 763         if (!path)
 764                 return -ENOMEM;
 765
 766         key.objectid = bytenr;
 767         key.type = BTRFS_EXTENT_ITEM_KEY;
 768         key.offset = num_bytes;
 769         if (!trans) {
 770                 path->skip_locking = 1;
 771                 path->search_commit_root = 1;
 772         }
 773 again:
 774         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 775                                 &key, path, 0, 0);
 776         if (ret < 0)
 777                 goto out_free;
 778
 779         if (ret == 0) {
 780                 leaf = path->nodes[0];
 781                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 782                 if (item_size >= sizeof(*ei)) {
 783                         ei = btrfs_item_ptr(leaf, path->slots[0],
 784                                             struct btrfs_extent_item);
 785                         num_refs = btrfs_extent_refs(leaf, ei);
 786                         extent_flags = btrfs_extent_flags(leaf, ei);
 787                 } else {
 788 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 789                         struct btrfs_extent_item_v0 *ei0;
 790                         BUG_ON(item_size != sizeof(*ei0));
 791                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 792                                              struct btrfs_extent_item_v0);
 793                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 794                         /* FIXME: this isn't correct for data */
 795                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 796 #else
 797                         BUG();
 798 #endif
 799                 }
 800                 BUG_ON(num_refs == 0);
 801         } else {
 802                 num_refs = 0;
 803                 extent_flags = 0;
 804                 ret = 0;
 805         }
 806
 807         if (!trans)
 808                 goto out;
 809
 810         delayed_refs = &trans->transaction->delayed_refs;
 811         spin_lock(&delayed_refs->lock);
 812         head = btrfs_find_delayed_ref_head(trans, bytenr);
 813         if (head) {
 814                 if (!mutex_trylock(&head->mutex)) {
 815                         atomic_inc(&head->node.refs);
 816                         spin_unlock(&delayed_refs->lock);
 817
 818                         btrfs_release_path(path);
 819
 820                         /*
 821                          * Mutex was contended, block until it's released and try
 822                          * again
 823                          */
 824                         mutex_lock(&head->mutex);
 825                         mutex_unlock(&head->mutex);
 826                         btrfs_put_delayed_ref(&head->node);
 827                         goto again;
 828                 }
 829                 if (head->extent_op && head->extent_op->update_flags)
 830                         extent_flags |= head->extent_op->flags_to_set;
 831                 else
 832                         BUG_ON(num_refs == 0);
 833
 834                 num_refs += head->node.ref_mod;
 835                 mutex_unlock(&head->mutex);
 836         }
 837         spin_unlock(&delayed_refs->lock);
 838 out:
 839         WARN_ON(num_refs == 0);
 840         if (refs)
 841                 *refs = num_refs;
 842         if (flags)
 843                 *flags = extent_flags;
 844 out_free:
 845         btrfs_free_path(path);
 846         return ret;
 847 }
 848
 849 /*
 850  * Back reference rules.  Back refs have three main goals:
 851  *
 852  * 1) differentiate between all holders of references to an extent so that
 853  *    when a reference is dropped we can make sure it was a valid reference
 854  *    before freeing the extent.
 855  *
 856  * 2) Provide enough information to quickly find the holders of an extent
 857  *    if we notice a given block is corrupted or bad.
 858  *
 859  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 860  *    maintenance.  This is actually the same as #2, but with a slightly
 861  *    different use case.
 862  *
 863  * There are two kinds of back refs. The implicit back refs is optimized
 864  * for pointers in non-shared tree blocks. For a given pointer in a block,
 865  * back refs of this kind provide information about the block's owner tree
 866  * and the pointer's key. These information allow us to find the block by
 867  * b-tree searching. The full back refs is for pointers in tree blocks not
 868  * referenced by their owner trees. The location of tree block is recorded
 869  * in the back refs. Actually the full back refs is generic, and can be
 870  * used in all cases the implicit back refs is used. The major shortcoming
 871  * of the full back refs is its overhead. Every time a tree block gets
 872  * COWed, we have to update back refs entry for all pointers in it.
 873  *
 874  * For a newly allocated tree block, we use implicit back refs for
 875  * pointers in it. This means most tree related operations only involve
 876  * implicit back refs. For a tree block created in old transaction, the
 877  * only way to drop a reference to it is COW it. So we can detect the
 878  * event that tree block loses its owner tree's reference and do the
 879  * back refs conversion.
 880  *
 881  * When a tree block is COW'd through a tree, there are four cases:
 882  *
 883  * The reference count of the block is one and the tree is the block's
 884  * owner tree. Nothing to do in this case.
 885  *
 886  * The reference count of the block is one and the tree is not the
 887  * block's owner tree. In this case, full back refs is used for pointers
 888  * in the block. Remove these full back refs, add implicit back refs for
 889  * every pointers in the new block.
 890  *
 891  * The reference count of the block is greater than one and the tree is
 892  * the block's owner tree. In this case, implicit back refs is used for
 893  * pointers in the block. Add full back refs for every pointers in the
 894  * block, increase lower level extents' reference counts. The original
 895  * implicit back refs are entailed to the new block.
 896  *
 897  * The reference count of the block is greater than one and the tree is
 898  * not the block's owner tree. Add implicit back refs for every pointer in
 899  * the new block, increase lower level extents' reference count.
 900  *
 901  * Back Reference Key composing:
 902  *
 903  * The key objectid corresponds to the first byte in the extent,
 904  * The key type is used to differentiate between types of back refs.
 905  * There are different meanings of the key offset for different types
 906  * of back refs.
 907  *
 908  * File extents can be referenced by:
 909  *
 910  * - multiple snapshots, subvolumes, or different generations in one subvol
 911  * - different files inside a single subvolume
 912  * - different offsets inside a file (bookend extents in file.c)
 913  *
 914  * The extent ref structure for the implicit back refs has fields for:
 915  *
 916  * - Objectid of the subvolume root
 917  * - objectid of the file holding the reference
 918  * - original offset in the file
 919  * - how many bookend extents
 920  *
 921  * The key offset for the implicit back refs is hash of the first
 922  * three fields.
 923  *
 924  * The extent ref structure for the full back refs has field for:
 925  *
 926  * - number of pointers in the tree leaf
 927  *
 928  * The key offset for the implicit back refs is the first byte of
 929  * the tree leaf
 930  *
 931  * When a file extent is allocated, The implicit back refs is used.
 932  * the fields are filled in:
 933  *
 934  *     (root_key.objectid, inode objectid, offset in file, 1)
 935  *
 936  * When a file extent is removed file truncation, we find the
 937  * corresponding implicit back refs and check the following fields:
 938  *
 939  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 940  *
 941  * Btree extents can be referenced by:
 942  *
 943  * - Different subvolumes
 944  *
 945  * Both the implicit back refs and the full back refs for tree blocks
 946  * only consist of key. The key offset for the implicit back refs is
 947  * objectid of block's owner tree. The key offset for the full back refs
 948  * is the first byte of parent block.
 949  *
 950  * When implicit back refs is used, information about the lowest key and
 951  * level of the tree block are required. These information are stored in
 952  * tree block info structure.
 953  */
 954
 955 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 956 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 957                                   struct btrfs_root *root,
 958                                   struct btrfs_path *path,
 959                                   u64 owner, u32 extra_size)
 960 {
 961         struct btrfs_extent_item *item;
 962         struct btrfs_extent_item_v0 *ei0;
 963         struct btrfs_extent_ref_v0 *ref0;
 964         struct btrfs_tree_block_info *bi;
 965         struct extent_buffer *leaf;
 966         struct btrfs_key key;
 967         struct btrfs_key found_key;
 968         u32 new_size = sizeof(*item);
 969         u64 refs;
 970         int ret;
 971
 972         leaf = path->nodes[0];
 973         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 974
 975         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 976         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 977                              struct btrfs_extent_item_v0);
 978         refs = btrfs_extent_refs_v0(leaf, ei0);
 979
 980         if (owner == (u64)-1) {
 981                 while (1) {
 982                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 983                                 ret = btrfs_next_leaf(root, path);
 984                                 if (ret < 0)
 985                                         return ret;
 986                                 BUG_ON(ret > 0); /* Corruption */
 987                                 leaf = path->nodes[0];
 988                         }
 989                         btrfs_item_key_to_cpu(leaf, &found_key,
 990                                               path->slots[0]);
 991                         BUG_ON(key.objectid != found_key.objectid);
 992                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 993                                 path->slots[0]++;
 994                                 continue;
 995                         }
 996                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 997                                               struct btrfs_extent_ref_v0);
 998                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 999                         break;
1000                 }
1001         }
1002         btrfs_release_path(path);
1003
1004         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1005                 new_size += sizeof(*bi);
1006
1007         new_size -= sizeof(*ei0);
1008         ret = btrfs_search_slot(trans, root, &key, path,
1009                                 new_size + extra_size, 1);
1010         if (ret < 0)
1011                 return ret;
1012         BUG_ON(ret); /* Corruption */
1013
1014         btrfs_extend_item(trans, root, path, new_size);
1015
1016         leaf = path->nodes[0];
1017         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1018         btrfs_set_extent_refs(leaf, item, refs);
1019         /* FIXME: get real generation */
1020         btrfs_set_extent_generation(leaf, item, 0);
1021         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1022                 btrfs_set_extent_flags(leaf, item,
1023                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1024                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1025                 bi = (struct btrfs_tree_block_info *)(item + 1);
1026                 /* FIXME: get first key of the block */
1027                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1028                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1029         } else {
1030                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1031         }
1032         btrfs_mark_buffer_dirty(leaf);
1033         return 0;
1034 }
1035 #endif
1036
1037 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1038 {
1039         u32 high_crc = ~(u32)0;
1040         u32 low_crc = ~(u32)0;
1041         __le64 lenum;
1042
1043         lenum = cpu_to_le64(root_objectid);
1044         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1045         lenum = cpu_to_le64(owner);
1046         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1047         lenum = cpu_to_le64(offset);
1048         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1049
1050         return ((u64)high_crc << 31) ^ (u64)low_crc;
1051 }
1052
1053 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1054                                      struct btrfs_extent_data_ref *ref)
1055 {
1056         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1057                                     btrfs_extent_data_ref_objectid(leaf, ref),
1058                                     btrfs_extent_data_ref_offset(leaf, ref));
1059 }
1060
1061 static int match_extent_data_ref(struct extent_buffer *leaf,
1062                                  struct btrfs_extent_data_ref *ref,
1063                                  u64 root_objectid, u64 owner, u64 offset)
1064 {
1065         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1066             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1067             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1068                 return 0;
1069         return 1;
1070 }
1071
1072 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1073                                            struct btrfs_root *root,
1074                                            struct btrfs_path *path,
1075                                            u64 bytenr, u64 parent,
1076                                            u64 root_objectid,
1077                                            u64 owner, u64 offset)
1078 {
1079         struct btrfs_key key;
1080         struct btrfs_extent_data_ref *ref;
1081         struct extent_buffer *leaf;
1082         u32 nritems;
1083         int ret;
1084         int recow;
1085         int err = -ENOENT;
1086
1087         key.objectid = bytenr;
1088         if (parent) {
1089                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1090                 key.offset = parent;
1091         } else {
1092                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1093                 key.offset = hash_extent_data_ref(root_objectid,
1094                                                   owner, offset);
1095         }
1096 again:
1097         recow = 0;
1098         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1099         if (ret < 0) {
1100                 err = ret;
1101                 goto fail;
1102         }
1103
1104         if (parent) {
1105                 if (!ret)
1106                         return 0;
1107 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1108                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1109                 btrfs_release_path(path);
1110                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1111                 if (ret < 0) {
1112                         err = ret;
1113                         goto fail;
1114                 }
1115                 if (!ret)
1116                         return 0;
1117 #endif
1118                 goto fail;
1119         }
1120
1121         leaf = path->nodes[0];
1122         nritems = btrfs_header_nritems(leaf);
1123         while (1) {
1124                 if (path->slots[0] >= nritems) {
1125                         ret = btrfs_next_leaf(root, path);
1126                         if (ret < 0)
1127                                 err = ret;
1128                         if (ret)
1129                                 goto fail;
1130
1131                         leaf = path->nodes[0];
1132                         nritems = btrfs_header_nritems(leaf);
1133                         recow = 1;
1134                 }
1135
1136                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1137                 if (key.objectid != bytenr ||
1138                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1139                         goto fail;
1140
1141                 ref = btrfs_item_ptr(leaf, path->slots[0],
1142                                      struct btrfs_extent_data_ref);
1143
1144                 if (match_extent_data_ref(leaf, ref, root_objectid,
1145                                           owner, offset)) {
1146                         if (recow) {
1147                                 btrfs_release_path(path);
1148                                 goto again;
1149                         }
1150                         err = 0;
1151                         break;
1152                 }
1153                 path->slots[0]++;
1154         }
1155 fail:
1156         return err;
1157 }
1158
1159 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1160                                            struct btrfs_root *root,
1161                                            struct btrfs_path *path,
1162                                            u64 bytenr, u64 parent,
1163                                            u64 root_objectid, u64 owner,
1164                                            u64 offset, int refs_to_add)
1165 {
1166         struct btrfs_key key;
1167         struct extent_buffer *leaf;
1168         u32 size;
1169         u32 num_refs;
1170         int ret;
1171
1172         key.objectid = bytenr;
1173         if (parent) {
1174                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1175                 key.offset = parent;
1176                 size = sizeof(struct btrfs_shared_data_ref);
1177         } else {
1178                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1179                 key.offset = hash_extent_data_ref(root_objectid,
1180                                                   owner, offset);
1181                 size = sizeof(struct btrfs_extent_data_ref);
1182         }
1183
1184         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1185         if (ret && ret != -EEXIST)
1186                 goto fail;
1187
1188         leaf = path->nodes[0];
1189         if (parent) {
1190                 struct btrfs_shared_data_ref *ref;
1191                 ref = btrfs_item_ptr(leaf, path->slots[0],
1192                                      struct btrfs_shared_data_ref);
1193                 if (ret == 0) {
1194                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1195                 } else {
1196                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1197                         num_refs += refs_to_add;
1198                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1199                 }
1200         } else {
1201                 struct btrfs_extent_data_ref *ref;
1202                 while (ret == -EEXIST) {
1203                         ref = btrfs_item_ptr(leaf, path->slots[0],
1204                                              struct btrfs_extent_data_ref);
1205                         if (match_extent_data_ref(leaf, ref, root_objectid,
1206                                                   owner, offset))
1207                                 break;
1208                         btrfs_release_path(path);
1209                         key.offset++;
1210                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1211                                                       size);
1212                         if (ret && ret != -EEXIST)
1213                                 goto fail;
1214
1215                         leaf = path->nodes[0];
1216                 }
1217                 ref = btrfs_item_ptr(leaf, path->slots[0],
1218                                      struct btrfs_extent_data_ref);
1219                 if (ret == 0) {
1220                         btrfs_set_extent_data_ref_root(leaf, ref,
1221                                                        root_objectid);
1222                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1223                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1224                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1225                 } else {
1226                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1227                         num_refs += refs_to_add;
1228                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1229                 }
1230         }
1231         btrfs_mark_buffer_dirty(leaf);
1232         ret = 0;
1233 fail:
1234         btrfs_release_path(path);
1235         return ret;
1236 }
1237
1238 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1239                                            struct btrfs_root *root,
1240                                            struct btrfs_path *path,
1241                                            int refs_to_drop)
1242 {
1243         struct btrfs_key key;
1244         struct btrfs_extent_data_ref *ref1 = NULL;
1245         struct btrfs_shared_data_ref *ref2 = NULL;
1246         struct extent_buffer *leaf;
1247         u32 num_refs = 0;
1248         int ret = 0;
1249
1250         leaf = path->nodes[0];
1251         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1252
1253         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1254                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1255                                       struct btrfs_extent_data_ref);
1256                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1257         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1258                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1259                                       struct btrfs_shared_data_ref);
1260                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1261 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1262         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1263                 struct btrfs_extent_ref_v0 *ref0;
1264                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1265                                       struct btrfs_extent_ref_v0);
1266                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1267 #endif
1268         } else {
1269                 BUG();
1270         }
1271
1272         BUG_ON(num_refs < refs_to_drop);
1273         num_refs -= refs_to_drop;
1274
1275         if (num_refs == 0) {
1276                 ret = btrfs_del_item(trans, root, path);
1277         } else {
1278                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1279                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1280                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1281                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1282 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1283                 else {
1284                         struct btrfs_extent_ref_v0 *ref0;
1285                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1286                                         struct btrfs_extent_ref_v0);
1287                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1288                 }
1289 #endif
1290                 btrfs_mark_buffer_dirty(leaf);
1291         }
1292         return ret;
1293 }
1294
1295 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1296                                           struct btrfs_path *path,
1297                                           struct btrfs_extent_inline_ref *iref)
1298 {
1299         struct btrfs_key key;
1300         struct extent_buffer *leaf;
1301         struct btrfs_extent_data_ref *ref1;
1302         struct btrfs_shared_data_ref *ref2;
1303         u32 num_refs = 0;
1304
1305         leaf = path->nodes[0];
1306         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1307         if (iref) {
1308                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1309                     BTRFS_EXTENT_DATA_REF_KEY) {
1310                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1311                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1312                 } else {
1313                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1314                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1315                 }
1316         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1317                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1318                                       struct btrfs_extent_data_ref);
1319                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1320         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1321                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1322                                       struct btrfs_shared_data_ref);
1323                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1324 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1325         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1326                 struct btrfs_extent_ref_v0 *ref0;
1327                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1328                                       struct btrfs_extent_ref_v0);
1329                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1330 #endif
1331         } else {
1332                 WARN_ON(1);
1333         }
1334         return num_refs;
1335 }
1336
1337 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1338                                           struct btrfs_root *root,
1339                                           struct btrfs_path *path,
1340                                           u64 bytenr, u64 parent,
1341                                           u64 root_objectid)
1342 {
1343         struct btrfs_key key;
1344         int ret;
1345
1346         key.objectid = bytenr;
1347         if (parent) {
1348                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1349                 key.offset = parent;
1350         } else {
1351                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1352                 key.offset = root_objectid;
1353         }
1354
1355         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1356         if (ret > 0)
1357                 ret = -ENOENT;
1358 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1359         if (ret == -ENOENT && parent) {
1360                 btrfs_release_path(path);
1361                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1362                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1363                 if (ret > 0)
1364                         ret = -ENOENT;
1365         }
1366 #endif
1367         return ret;
1368 }
1369
1370 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1371                                           struct btrfs_root *root,
1372                                           struct btrfs_path *path,
1373                                           u64 bytenr, u64 parent,
1374                                           u64 root_objectid)
1375 {
1376         struct btrfs_key key;
1377         int ret;
1378
1379         key.objectid = bytenr;
1380         if (parent) {
1381                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1382                 key.offset = parent;
1383         } else {
1384                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1385                 key.offset = root_objectid;
1386         }
1387
1388         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1389         btrfs_release_path(path);
1390         return ret;
1391 }
1392
1393 static inline int extent_ref_type(u64 parent, u64 owner)
1394 {
1395         int type;
1396         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1397                 if (parent > 0)
1398                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1399                 else
1400                         type = BTRFS_TREE_BLOCK_REF_KEY;
1401         } else {
1402                 if (parent > 0)
1403                         type = BTRFS_SHARED_DATA_REF_KEY;
1404                 else
1405                         type = BTRFS_EXTENT_DATA_REF_KEY;
1406         }
1407         return type;
1408 }
1409
1410 static int find_next_key(struct btrfs_path *path, int level,
1411                          struct btrfs_key *key)
1412
1413 {
1414         for (; level < BTRFS_MAX_LEVEL; level++) {
1415                 if (!path->nodes[level])
1416                         break;
1417                 if (path->slots[level] + 1 >=
1418                     btrfs_header_nritems(path->nodes[level]))
1419                         continue;
1420                 if (level == 0)
1421                         btrfs_item_key_to_cpu(path->nodes[level], key,
1422                                               path->slots[level] + 1);
1423                 else
1424                         btrfs_node_key_to_cpu(path->nodes[level], key,
1425                                               path->slots[level] + 1);
1426                 return 0;
1427         }
1428         return 1;
1429 }
1430
1431 /*
1432  * look for inline back ref. if back ref is found, *ref_ret is set
1433  * to the address of inline back ref, and 0 is returned.
1434  *
1435  * if back ref isn't found, *ref_ret is set to the address where it
1436  * should be inserted, and -ENOENT is returned.
1437  *
1438  * if insert is true and there are too many inline back refs, the path
1439  * points to the extent item, and -EAGAIN is returned.
1440  *
1441  * NOTE: inline back refs are ordered in the same way that back ref
1442  *       items in the tree are ordered.
1443  */
1444 static noinline_for_stack
1445 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1446                                  struct btrfs_root *root,
1447                                  struct btrfs_path *path,
1448                                  struct btrfs_extent_inline_ref **ref_ret,
1449                                  u64 bytenr, u64 num_bytes,
1450                                  u64 parent, u64 root_objectid,
1451                                  u64 owner, u64 offset, int insert)
1452 {
1453         struct btrfs_key key;
1454         struct extent_buffer *leaf;
1455         struct btrfs_extent_item *ei;
1456         struct btrfs_extent_inline_ref *iref;
1457         u64 flags;
1458         u64 item_size;
1459         unsigned long ptr;
1460         unsigned long end;
1461         int extra_size;
1462         int type;
1463         int want;
1464         int ret;
1465         int err = 0;
1466
1467         key.objectid = bytenr;
1468         key.type = BTRFS_EXTENT_ITEM_KEY;
1469         key.offset = num_bytes;
1470
1471         want = extent_ref_type(parent, owner);
1472         if (insert) {
1473                 extra_size = btrfs_extent_inline_ref_size(want);
1474                 path->keep_locks = 1;
1475         } else
1476                 extra_size = -1;
1477         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1478         if (ret < 0) {
1479                 err = ret;
1480                 goto out;
1481         }
1482         if (ret && !insert) {
1483                 err = -ENOENT;
1484                 goto out;
1485         }
1486         BUG_ON(ret); /* Corruption */
1487
1488         leaf = path->nodes[0];
1489         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1490 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1491         if (item_size < sizeof(*ei)) {
1492                 if (!insert) {
1493                         err = -ENOENT;
1494                         goto out;
1495                 }
1496                 ret = convert_extent_item_v0(trans, root, path, owner,
1497                                              extra_size);
1498                 if (ret < 0) {
1499                         err = ret;
1500                         goto out;
1501                 }
1502                 leaf = path->nodes[0];
1503                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1504         }
1505 #endif
1506         BUG_ON(item_size < sizeof(*ei));
1507
1508         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1509         flags = btrfs_extent_flags(leaf, ei);
1510
1511         ptr = (unsigned long)(ei + 1);
1512         end = (unsigned long)ei + item_size;
1513
1514         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1515                 ptr += sizeof(struct btrfs_tree_block_info);
1516                 BUG_ON(ptr > end);
1517         } else {
1518                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1519         }
1520
1521         err = -ENOENT;
1522         while (1) {
1523                 if (ptr >= end) {
1524                         WARN_ON(ptr > end);
1525                         break;
1526                 }
1527                 iref = (struct btrfs_extent_inline_ref *)ptr;
1528                 type = btrfs_extent_inline_ref_type(leaf, iref);
1529                 if (want < type)
1530                         break;
1531                 if (want > type) {
1532                         ptr += btrfs_extent_inline_ref_size(type);
1533                         continue;
1534                 }
1535
1536                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1537                         struct btrfs_extent_data_ref *dref;
1538                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1539                         if (match_extent_data_ref(leaf, dref, root_objectid,
1540                                                   owner, offset)) {
1541                                 err = 0;
1542                                 break;
1543                         }
1544                         if (hash_extent_data_ref_item(leaf, dref) <
1545                             hash_extent_data_ref(root_objectid, owner, offset))
1546                                 break;
1547                 } else {
1548                         u64 ref_offset;
1549                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1550                         if (parent > 0) {
1551                                 if (parent == ref_offset) {
1552                                         err = 0;
1553                                         break;
1554                                 }
1555                                 if (ref_offset < parent)
1556                                         break;
1557                         } else {
1558                                 if (root_objectid == ref_offset) {
1559                                         err = 0;
1560                                         break;
1561                                 }
1562                                 if (ref_offset < root_objectid)
1563                                         break;
1564                         }
1565                 }
1566                 ptr += btrfs_extent_inline_ref_size(type);
1567         }
1568         if (err == -ENOENT && insert) {
1569                 if (item_size + extra_size >=
1570                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1571                         err = -EAGAIN;
1572                         goto out;
1573                 }
1574                 /*
1575                  * To add new inline back ref, we have to make sure
1576                  * there is no corresponding back ref item.
1577                  * For simplicity, we just do not add new inline back
1578                  * ref if there is any kind of item for this block
1579                  */
1580                 if (find_next_key(path, 0, &key) == 0 &&
1581                     key.objectid == bytenr &&
1582                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1583                         err = -EAGAIN;
1584                         goto out;
1585                 }
1586         }
1587         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1588 out:
1589         if (insert) {
1590                 path->keep_locks = 0;
1591                 btrfs_unlock_up_safe(path, 1);
1592         }
1593         return err;
1594 }
1595
1596 /*
1597  * helper to add new inline back ref
1598  */
1599 static noinline_for_stack
1600 void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1601                                  struct btrfs_root *root,
1602                                  struct btrfs_path *path,
1603                                  struct btrfs_extent_inline_ref *iref,
1604                                  u64 parent, u64 root_objectid,
1605                                  u64 owner, u64 offset, int refs_to_add,
1606                                  struct btrfs_delayed_extent_op *extent_op)
1607 {
1608         struct extent_buffer *leaf;
1609         struct btrfs_extent_item *ei;
1610         unsigned long ptr;
1611         unsigned long end;
1612         unsigned long item_offset;
1613         u64 refs;
1614         int size;
1615         int type;
1616
1617         leaf = path->nodes[0];
1618         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1619         item_offset = (unsigned long)iref - (unsigned long)ei;
1620
1621         type = extent_ref_type(parent, owner);
1622         size = btrfs_extent_inline_ref_size(type);
1623
1624         btrfs_extend_item(trans, root, path, size);
1625
1626         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1627         refs = btrfs_extent_refs(leaf, ei);
1628         refs += refs_to_add;
1629         btrfs_set_extent_refs(leaf, ei, refs);
1630         if (extent_op)
1631                 __run_delayed_extent_op(extent_op, leaf, ei);
1632
1633         ptr = (unsigned long)ei + item_offset;
1634         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1635         if (ptr < end - size)
1636                 memmove_extent_buffer(leaf, ptr + size, ptr,
1637                                       end - size - ptr);
1638
1639         iref = (struct btrfs_extent_inline_ref *)ptr;
1640         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1641         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1642                 struct btrfs_extent_data_ref *dref;
1643                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1644                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1645                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1646                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1647                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1648         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1649                 struct btrfs_shared_data_ref *sref;
1650                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1651                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1652                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1653         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1654                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1655         } else {
1656                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1657         }
1658         btrfs_mark_buffer_dirty(leaf);
1659 }
1660
1661 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1662                                  struct btrfs_root *root,
1663                                  struct btrfs_path *path,
1664                                  struct btrfs_extent_inline_ref **ref_ret,
1665                                  u64 bytenr, u64 num_bytes, u64 parent,
1666                                  u64 root_objectid, u64 owner, u64 offset)
1667 {
1668         int ret;
1669
1670         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1671                                            bytenr, num_bytes, parent,
1672                                            root_objectid, owner, offset, 0);
1673         if (ret != -ENOENT)
1674                 return ret;
1675
1676         btrfs_release_path(path);
1677         *ref_ret = NULL;
1678
1679         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1680                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1681                                             root_objectid);
1682         } else {
1683                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1684                                              root_objectid, owner, offset);
1685         }
1686         return ret;
1687 }
1688
1689 /*
1690  * helper to update/remove inline back ref
1691  */
1692 static noinline_for_stack
1693 void update_inline_extent_backref(struct btrfs_trans_handle *trans,
1694                                   struct btrfs_root *root,
1695                                   struct btrfs_path *path,
1696                                   struct btrfs_extent_inline_ref *iref,
1697                                   int refs_to_mod,
1698                                   struct btrfs_delayed_extent_op *extent_op)
1699 {
1700         struct extent_buffer *leaf;
1701         struct btrfs_extent_item *ei;
1702         struct btrfs_extent_data_ref *dref = NULL;
1703         struct btrfs_shared_data_ref *sref = NULL;
1704         unsigned long ptr;
1705         unsigned long end;
1706         u32 item_size;
1707         int size;
1708         int type;
1709         u64 refs;
1710
1711         leaf = path->nodes[0];
1712         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1713         refs = btrfs_extent_refs(leaf, ei);
1714         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1715         refs += refs_to_mod;
1716         btrfs_set_extent_refs(leaf, ei, refs);
1717         if (extent_op)
1718                 __run_delayed_extent_op(extent_op, leaf, ei);
1719
1720         type = btrfs_extent_inline_ref_type(leaf, iref);
1721
1722         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1723                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1724                 refs = btrfs_extent_data_ref_count(leaf, dref);
1725         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1726                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1727                 refs = btrfs_shared_data_ref_count(leaf, sref);
1728         } else {
1729                 refs = 1;
1730                 BUG_ON(refs_to_mod != -1);
1731         }
1732
1733         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1734         refs += refs_to_mod;
1735
1736         if (refs > 0) {
1737                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1738                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1739                 else
1740                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1741         } else {
1742                 size =  btrfs_extent_inline_ref_size(type);
1743                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1744                 ptr = (unsigned long)iref;
1745                 end = (unsigned long)ei + item_size;
1746                 if (ptr + size < end)
1747                         memmove_extent_buffer(leaf, ptr, ptr + size,
1748                                               end - ptr - size);
1749                 item_size -= size;
1750                 btrfs_truncate_item(trans, root, path, item_size, 1);
1751         }
1752         btrfs_mark_buffer_dirty(leaf);
1753 }
1754
1755 static noinline_for_stack
1756 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1757                                  struct btrfs_root *root,
1758                                  struct btrfs_path *path,
1759                                  u64 bytenr, u64 num_bytes, u64 parent,
1760                                  u64 root_objectid, u64 owner,
1761                                  u64 offset, int refs_to_add,
1762                                  struct btrfs_delayed_extent_op *extent_op)
1763 {
1764         struct btrfs_extent_inline_ref *iref;
1765         int ret;
1766
1767         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1768                                            bytenr, num_bytes, parent,
1769                                            root_objectid, owner, offset, 1);
1770         if (ret == 0) {
1771                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1772                 update_inline_extent_backref(trans, root, path, iref,
1773                                              refs_to_add, extent_op);
1774         } else if (ret == -ENOENT) {
1775                 setup_inline_extent_backref(trans, root, path, iref, parent,
1776                                             root_objectid, owner, offset,
1777                                             refs_to_add, extent_op);
1778                 ret = 0;
1779         }
1780         return ret;
1781 }
1782
1783 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1784                                  struct btrfs_root *root,
1785                                  struct btrfs_path *path,
1786                                  u64 bytenr, u64 parent, u64 root_objectid,
1787                                  u64 owner, u64 offset, int refs_to_add)
1788 {
1789         int ret;
1790         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1791                 BUG_ON(refs_to_add != 1);
1792                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1793                                             parent, root_objectid);
1794         } else {
1795                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1796                                              parent, root_objectid,
1797                                              owner, offset, refs_to_add);
1798         }
1799         return ret;
1800 }
1801
1802 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1803                                  struct btrfs_root *root,
1804                                  struct btrfs_path *path,
1805                                  struct btrfs_extent_inline_ref *iref,
1806                                  int refs_to_drop, int is_data)
1807 {
1808         int ret = 0;
1809
1810         BUG_ON(!is_data && refs_to_drop != 1);
1811         if (iref) {
1812                 update_inline_extent_backref(trans, root, path, iref,
1813                                              -refs_to_drop, NULL);
1814         } else if (is_data) {
1815                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1816         } else {
1817                 ret = btrfs_del_item(trans, root, path);
1818         }
1819         return ret;
1820 }
1821
1822 static int btrfs_issue_discard(struct block_device *bdev,
1823                                 u64 start, u64 len)
1824 {
1825         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1826 }
1827
1828 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1829                                 u64 num_bytes, u64 *actual_bytes)
1830 {
1831         int ret;
1832         u64 discarded_bytes = 0;
1833         struct btrfs_bio *bbio = NULL;
1834
1835
1836         /* Tell the block device(s) that the sectors can be discarded */
1837         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1838                               bytenr, &num_bytes, &bbio, 0);
1839         /* Error condition is -ENOMEM */
1840         if (!ret) {
1841                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1842                 int i;
1843
1844
1845                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1846                         if (!stripe->dev->can_discard)
1847                                 continue;
1848
1849                         ret = btrfs_issue_discard(stripe->dev->bdev,
1850                                                   stripe->physical,
1851                                                   stripe->length);
1852                         if (!ret)
1853                                 discarded_bytes += stripe->length;
1854                         else if (ret != -EOPNOTSUPP)
1855                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1856
1857                         /*
1858                          * Just in case we get back EOPNOTSUPP for some reason,
1859                          * just ignore the return value so we don't screw up
1860                          * people calling discard_extent.
1861                          */
1862                         ret = 0;
1863                 }
1864                 kfree(bbio);
1865         }
1866
1867         if (actual_bytes)
1868                 *actual_bytes = discarded_bytes;
1869
1870
1871         return ret;
1872 }
1873
1874 /* Can return -ENOMEM */
1875 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1876                          struct btrfs_root *root,
1877                          u64 bytenr, u64 num_bytes, u64 parent,
1878                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1879 {
1880         int ret;
1881         struct btrfs_fs_info *fs_info = root->fs_info;
1882
1883         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1884                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1885
1886         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1887                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1888                                         num_bytes,
1889                                         parent, root_objectid, (int)owner,
1890                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1891         } else {
1892                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1893                                         num_bytes,
1894                                         parent, root_objectid, owner, offset,
1895                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1896         }
1897         return ret;
1898 }
1899
1900 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1901                                   struct btrfs_root *root,
1902                                   u64 bytenr, u64 num_bytes,
1903                                   u64 parent, u64 root_objectid,
1904                                   u64 owner, u64 offset, int refs_to_add,
1905                                   struct btrfs_delayed_extent_op *extent_op)
1906 {
1907         struct btrfs_path *path;
1908         struct extent_buffer *leaf;
1909         struct btrfs_extent_item *item;
1910         u64 refs;
1911         int ret;
1912         int err = 0;
1913
1914         path = btrfs_alloc_path();
1915         if (!path)
1916                 return -ENOMEM;
1917
1918         path->reada = 1;
1919         path->leave_spinning = 1;
1920         /* this will setup the path even if it fails to insert the back ref */
1921         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1922                                            path, bytenr, num_bytes, parent,
1923                                            root_objectid, owner, offset,
1924                                            refs_to_add, extent_op);
1925         if (ret == 0)
1926                 goto out;
1927
1928         if (ret != -EAGAIN) {
1929                 err = ret;
1930                 goto out;
1931         }
1932
1933         leaf = path->nodes[0];
1934         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1935         refs = btrfs_extent_refs(leaf, item);
1936         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1937         if (extent_op)
1938                 __run_delayed_extent_op(extent_op, leaf, item);
1939
1940         btrfs_mark_buffer_dirty(leaf);
1941         btrfs_release_path(path);
1942
1943         path->reada = 1;
1944         path->leave_spinning = 1;
1945
1946         /* now insert the actual backref */
1947         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1948                                     path, bytenr, parent, root_objectid,
1949                                     owner, offset, refs_to_add);
1950         if (ret)
1951                 btrfs_abort_transaction(trans, root, ret);
1952 out:
1953         btrfs_free_path(path);
1954         return err;
1955 }
1956
1957 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1958                                 struct btrfs_root *root,
1959                                 struct btrfs_delayed_ref_node *node,
1960                                 struct btrfs_delayed_extent_op *extent_op,
1961                                 int insert_reserved)
1962 {
1963         int ret = 0;
1964         struct btrfs_delayed_data_ref *ref;
1965         struct btrfs_key ins;
1966         u64 parent = 0;
1967         u64 ref_root = 0;
1968         u64 flags = 0;
1969
1970         ins.objectid = node->bytenr;
1971         ins.offset = node->num_bytes;
1972         ins.type = BTRFS_EXTENT_ITEM_KEY;
1973
1974         ref = btrfs_delayed_node_to_data_ref(node);
1975         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1976                 parent = ref->parent;
1977         else
1978                 ref_root = ref->root;
1979
1980         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1981                 if (extent_op) {
1982                         BUG_ON(extent_op->update_key);
1983                         flags |= extent_op->flags_to_set;
1984                 }
1985                 ret = alloc_reserved_file_extent(trans, root,
1986                                                  parent, ref_root, flags,
1987                                                  ref->objectid, ref->offset,
1988                                                  &ins, node->ref_mod);
1989         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1990                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1991                                              node->num_bytes, parent,
1992                                              ref_root, ref->objectid,
1993                                              ref->offset, node->ref_mod,
1994                                              extent_op);
1995         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1996                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1997                                           node->num_bytes, parent,
1998                                           ref_root, ref->objectid,
1999                                           ref->offset, node->ref_mod,
2000                                           extent_op);
2001         } else {
2002                 BUG();
2003         }
2004         return ret;
2005 }
2006
2007 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2008                                     struct extent_buffer *leaf,
2009                                     struct btrfs_extent_item *ei)
2010 {
2011         u64 flags = btrfs_extent_flags(leaf, ei);
2012         if (extent_op->update_flags) {
2013                 flags |= extent_op->flags_to_set;
2014                 btrfs_set_extent_flags(leaf, ei, flags);
2015         }
2016
2017         if (extent_op->update_key) {
2018                 struct btrfs_tree_block_info *bi;
2019                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2020                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2021                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2022         }
2023 }
2024
2025 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2026                                  struct btrfs_root *root,
2027                                  struct btrfs_delayed_ref_node *node,
2028                                  struct btrfs_delayed_extent_op *extent_op)
2029 {
2030         struct btrfs_key key;
2031         struct btrfs_path *path;
2032         struct btrfs_extent_item *ei;
2033         struct extent_buffer *leaf;
2034         u32 item_size;
2035         int ret;
2036         int err = 0;
2037
2038         if (trans->aborted)
2039                 return 0;
2040
2041         path = btrfs_alloc_path();
2042         if (!path)
2043                 return -ENOMEM;
2044
2045         key.objectid = node->bytenr;
2046         key.type = BTRFS_EXTENT_ITEM_KEY;
2047         key.offset = node->num_bytes;
2048
2049         path->reada = 1;
2050         path->leave_spinning = 1;
2051         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2052                                 path, 0, 1);
2053         if (ret < 0) {
2054                 err = ret;
2055                 goto out;
2056         }
2057         if (ret > 0) {
2058                 err = -EIO;
2059                 goto out;
2060         }
2061
2062         leaf = path->nodes[0];
2063         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2064 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2065         if (item_size < sizeof(*ei)) {
2066                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2067                                              path, (u64)-1, 0);
2068                 if (ret < 0) {
2069                         err = ret;
2070                         goto out;
2071                 }
2072                 leaf = path->nodes[0];
2073                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2074         }
2075 #endif
2076         BUG_ON(item_size < sizeof(*ei));
2077         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2078         __run_delayed_extent_op(extent_op, leaf, ei);
2079
2080         btrfs_mark_buffer_dirty(leaf);
2081 out:
2082         btrfs_free_path(path);
2083         return err;
2084 }
2085
2086 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2087                                 struct btrfs_root *root,
2088                                 struct btrfs_delayed_ref_node *node,
2089                                 struct btrfs_delayed_extent_op *extent_op,
2090                                 int insert_reserved)
2091 {
2092         int ret = 0;
2093         struct btrfs_delayed_tree_ref *ref;
2094         struct btrfs_key ins;
2095         u64 parent = 0;
2096         u64 ref_root = 0;
2097
2098         ins.objectid = node->bytenr;
2099         ins.offset = node->num_bytes;
2100         ins.type = BTRFS_EXTENT_ITEM_KEY;
2101
2102         ref = btrfs_delayed_node_to_tree_ref(node);
2103         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2104                 parent = ref->parent;
2105         else
2106                 ref_root = ref->root;
2107
2108         BUG_ON(node->ref_mod != 1);
2109         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2110                 BUG_ON(!extent_op || !extent_op->update_flags ||
2111                        !extent_op->update_key);
2112                 ret = alloc_reserved_tree_block(trans, root,
2113                                                 parent, ref_root,
2114                                                 extent_op->flags_to_set,
2115                                                 &extent_op->key,
2116                                                 ref->level, &ins);
2117         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2118                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2119                                              node->num_bytes, parent, ref_root,
2120                                              ref->level, 0, 1, extent_op);
2121         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2122                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2123                                           node->num_bytes, parent, ref_root,
2124                                           ref->level, 0, 1, extent_op);
2125         } else {
2126                 BUG();
2127         }
2128         return ret;
2129 }
2130
2131 /* helper function to actually process a single delayed ref entry */
2132 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2133                                struct btrfs_root *root,
2134                                struct btrfs_delayed_ref_node *node,
2135                                struct btrfs_delayed_extent_op *extent_op,
2136                                int insert_reserved)
2137 {
2138         int ret = 0;
2139
2140         if (trans->aborted)
2141                 return 0;
2142
2143         if (btrfs_delayed_ref_is_head(node)) {
2144                 struct btrfs_delayed_ref_head *head;
2145                 /*
2146                  * we've hit the end of the chain and we were supposed
2147                  * to insert this extent into the tree.  But, it got
2148                  * deleted before we ever needed to insert it, so all
2149                  * we have to do is clean up the accounting
2150                  */
2151                 BUG_ON(extent_op);
2152                 head = btrfs_delayed_node_to_head(node);
2153                 if (insert_reserved) {
2154                         btrfs_pin_extent(root, node->bytenr,
2155                                          node->num_bytes, 1);
2156                         if (head->is_data) {
2157                                 ret = btrfs_del_csums(trans, root,
2158                                                       node->bytenr,
2159                                                       node->num_bytes);
2160                         }
2161                 }
2162                 mutex_unlock(&head->mutex);
2163                 return ret;
2164         }
2165
2166         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2167             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2168                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2169                                            insert_reserved);
2170         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2171                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2172                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2173                                            insert_reserved);
2174         else
2175                 BUG();
2176         return ret;
2177 }
2178
2179 static noinline struct btrfs_delayed_ref_node *
2180 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2181 {
2182         struct rb_node *node;
2183         struct btrfs_delayed_ref_node *ref;
2184         int action = BTRFS_ADD_DELAYED_REF;
2185 again:
2186         /*
2187          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2188          * this prevents ref count from going down to zero when
2189          * there still are pending delayed ref.
2190          */
2191         node = rb_prev(&head->node.rb_node);
2192         while (1) {
2193                 if (!node)
2194                         break;
2195                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2196                                 rb_node);
2197                 if (ref->bytenr != head->node.bytenr)
2198                         break;
2199                 if (ref->action == action)
2200                         return ref;
2201                 node = rb_prev(node);
2202         }
2203         if (action == BTRFS_ADD_DELAYED_REF) {
2204                 action = BTRFS_DROP_DELAYED_REF;
2205                 goto again;
2206         }
2207         return NULL;
2208 }
2209
2210 /*
2211  * Returns 0 on success or if called with an already aborted transaction.
2212  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2213  */
2214 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2215                                        struct btrfs_root *root,
2216                                        struct list_head *cluster)
2217 {
2218         struct btrfs_delayed_ref_root *delayed_refs;
2219         struct btrfs_delayed_ref_node *ref;
2220         struct btrfs_delayed_ref_head *locked_ref = NULL;
2221         struct btrfs_delayed_extent_op *extent_op;
2222         struct btrfs_fs_info *fs_info = root->fs_info;
2223         int ret;
2224         int count = 0;
2225         int must_insert_reserved = 0;
2226
2227         delayed_refs = &trans->transaction->delayed_refs;
2228         while (1) {
2229                 if (!locked_ref) {
2230                         /* pick a new head ref from the cluster list */
2231                         if (list_empty(cluster))
2232                                 break;
2233
2234                         locked_ref = list_entry(cluster->next,
2235                                      struct btrfs_delayed_ref_head, cluster);
2236
2237                         /* grab the lock that says we are going to process
2238                          * all the refs for this head */
2239                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2240
2241                         /*
2242                          * we may have dropped the spin lock to get the head
2243                          * mutex lock, and that might have given someone else
2244                          * time to free the head.  If that's true, it has been
2245                          * removed from our list and we can move on.
2246                          */
2247                         if (ret == -EAGAIN) {
2248                                 locked_ref = NULL;
2249                                 count++;
2250                                 continue;
2251                         }
2252                 }
2253
2254                 /*
2255                  * locked_ref is the head node, so we have to go one
2256                  * node back for any delayed ref updates
2257                  */
2258                 ref = select_delayed_ref(locked_ref);
2259
2260                 if (ref && ref->seq &&
2261                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2262                         /*
2263                          * there are still refs with lower seq numbers in the
2264                          * process of being added. Don't run this ref yet.
2265                          */
2266                         list_del_init(&locked_ref->cluster);
2267                         mutex_unlock(&locked_ref->mutex);
2268                         locked_ref = NULL;
2269                         delayed_refs->num_heads_ready++;
2270                         spin_unlock(&delayed_refs->lock);
2271                         cond_resched();
2272                         spin_lock(&delayed_refs->lock);
2273                         continue;
2274                 }
2275
2276                 /*
2277                  * record the must insert reserved flag before we
2278                  * drop the spin lock.
2279                  */
2280                 must_insert_reserved = locked_ref->must_insert_reserved;
2281                 locked_ref->must_insert_reserved = 0;
2282
2283                 extent_op = locked_ref->extent_op;
2284                 locked_ref->extent_op = NULL;
2285
2286                 if (!ref) {
2287                         /* All delayed refs have been processed, Go ahead
2288                          * and send the head node to run_one_delayed_ref,
2289                          * so that any accounting fixes can happen
2290                          */
2291                         ref = &locked_ref->node;
2292
2293                         if (extent_op && must_insert_reserved) {
2294                                 kfree(extent_op);
2295                                 extent_op = NULL;
2296                         }
2297
2298                         if (extent_op) {
2299                                 spin_unlock(&delayed_refs->lock);
2300
2301                                 ret = run_delayed_extent_op(trans, root,
2302                                                             ref, extent_op);
2303                                 kfree(extent_op);
2304
2305                                 if (ret) {
2306                                         printk(KERN_DEBUG "btrfs: run_delayed_extent_op returned %d\n", ret);
2307                                         spin_lock(&delayed_refs->lock);
2308                                         return ret;
2309                                 }
2310
2311                                 goto next;
2312                         }
2313
2314                         list_del_init(&locked_ref->cluster);
2315                         locked_ref = NULL;
2316                 }
2317
2318                 ref->in_tree = 0;
2319                 rb_erase(&ref->rb_node, &delayed_refs->root);
2320                 delayed_refs->num_entries--;
2321                 if (locked_ref) {
2322                         /*
2323                          * when we play the delayed ref, also correct the
2324                          * ref_mod on head
2325                          */
2326                         switch (ref->action) {
2327                         case BTRFS_ADD_DELAYED_REF:
2328                         case BTRFS_ADD_DELAYED_EXTENT:
2329                                 locked_ref->node.ref_mod -= ref->ref_mod;
2330                                 break;
2331                         case BTRFS_DROP_DELAYED_REF:
2332                                 locked_ref->node.ref_mod += ref->ref_mod;
2333                                 break;
2334                         default:
2335                                 WARN_ON(1);
2336                         }
2337                 }
2338                 spin_unlock(&delayed_refs->lock);
2339
2340                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2341                                           must_insert_reserved);
2342
2343                 btrfs_put_delayed_ref(ref);
2344                 kfree(extent_op);
2345                 count++;
2346
2347                 if (ret) {
2348                         printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
2349                         spin_lock(&delayed_refs->lock);
2350                         return ret;
2351                 }
2352
2353 next:
2354                 do_chunk_alloc(trans, fs_info->extent_root,
2355                                2 * 1024 * 1024,
2356                                btrfs_get_alloc_profile(root, 0),
2357                                CHUNK_ALLOC_NO_FORCE);
2358                 cond_resched();
2359                 spin_lock(&delayed_refs->lock);
2360         }
2361         return count;
2362 }
2363
2364 #ifdef SCRAMBLE_DELAYED_REFS
2365 /*
2366  * Normally delayed refs get processed in ascending bytenr order. This
2367  * correlates in most cases to the order added. To expose dependencies on this
2368  * order, we start to process the tree in the middle instead of the beginning
2369  */
2370 static u64 find_middle(struct rb_root *root)
2371 {
2372         struct rb_node *n = root->rb_node;
2373         struct btrfs_delayed_ref_node *entry;
2374         int alt = 1;
2375         u64 middle;
2376         u64 first = 0, last = 0;
2377
2378         n = rb_first(root);
2379         if (n) {
2380                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2381                 first = entry->bytenr;
2382         }
2383         n = rb_last(root);
2384         if (n) {
2385                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2386                 last = entry->bytenr;
2387         }
2388         n = root->rb_node;
2389
2390         while (n) {
2391                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2392                 WARN_ON(!entry->in_tree);
2393
2394                 middle = entry->bytenr;
2395
2396                 if (alt)
2397                         n = n->rb_left;
2398                 else
2399                         n = n->rb_right;
2400
2401                 alt = 1 - alt;
2402         }
2403         return middle;
2404 }
2405 #endif
2406
2407 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2408                                          struct btrfs_fs_info *fs_info)
2409 {
2410         struct qgroup_update *qgroup_update;
2411         int ret = 0;
2412
2413         if (list_empty(&trans->qgroup_ref_list) !=
2414             !trans->delayed_ref_elem.seq) {
2415                 /* list without seq or seq without list */
2416                 printk(KERN_ERR "btrfs: qgroup accounting update error, list is%s empty, seq is %llu\n",
2417                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2418                         trans->delayed_ref_elem.seq);
2419                 BUG();
2420         }
2421
2422         if (!trans->delayed_ref_elem.seq)
2423                 return 0;
2424
2425         while (!list_empty(&trans->qgroup_ref_list)) {
2426                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2427                                                  struct qgroup_update, list);
2428                 list_del(&qgroup_update->list);
2429                 if (!ret)
2430                         ret = btrfs_qgroup_account_ref(
2431                                         trans, fs_info, qgroup_update->node,
2432                                         qgroup_update->extent_op);
2433                 kfree(qgroup_update);
2434         }
2435
2436         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2437
2438         return ret;
2439 }
2440
2441 /*
2442  * this starts processing the delayed reference count updates and
2443  * extent insertions we have queued up so far.  count can be
2444  * 0, which means to process everything in the tree at the start
2445  * of the run (but not newly added entries), or it can be some target
2446  * number you'd like to process.
2447  *
2448  * Returns 0 on success or if called with an aborted transaction
2449  * Returns <0 on error and aborts the transaction
2450  */
2451 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2452                            struct btrfs_root *root, unsigned long count)
2453 {
2454         struct rb_node *node;
2455         struct btrfs_delayed_ref_root *delayed_refs;
2456         struct btrfs_delayed_ref_node *ref;
2457         struct list_head cluster;
2458         int ret;
2459         u64 delayed_start;
2460         int run_all = count == (unsigned long)-1;
2461         int run_most = 0;
2462         int loops;
2463
2464         /* We'll clean this up in btrfs_cleanup_transaction */
2465         if (trans->aborted)
2466                 return 0;
2467
2468         if (root == root->fs_info->extent_root)
2469                 root = root->fs_info->tree_root;
2470
2471         do_chunk_alloc(trans, root->fs_info->extent_root,
2472                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2473                        CHUNK_ALLOC_NO_FORCE);
2474
2475         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2476
2477         delayed_refs = &trans->transaction->delayed_refs;
2478         INIT_LIST_HEAD(&cluster);
2479 again:
2480         loops = 0;
2481         spin_lock(&delayed_refs->lock);
2482
2483 #ifdef SCRAMBLE_DELAYED_REFS
2484         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2485 #endif
2486
2487         if (count == 0) {
2488                 count = delayed_refs->num_entries * 2;
2489                 run_most = 1;
2490         }
2491         while (1) {
2492                 if (!(run_all || run_most) &&
2493                     delayed_refs->num_heads_ready < 64)
2494                         break;
2495
2496                 /*
2497                  * go find something we can process in the rbtree.  We start at
2498                  * the beginning of the tree, and then build a cluster
2499                  * of refs to process starting at the first one we are able to
2500                  * lock
2501                  */
2502                 delayed_start = delayed_refs->run_delayed_start;
2503                 ret = btrfs_find_ref_cluster(trans, &cluster,
2504                                              delayed_refs->run_delayed_start);
2505                 if (ret)
2506                         break;
2507
2508                 ret = run_clustered_refs(trans, root, &cluster);
2509                 if (ret < 0) {
2510                         spin_unlock(&delayed_refs->lock);
2511                         btrfs_abort_transaction(trans, root, ret);
2512                         return ret;
2513                 }
2514
2515                 count -= min_t(unsigned long, ret, count);
2516
2517                 if (count == 0)
2518                         break;
2519
2520                 if (delayed_start >= delayed_refs->run_delayed_start) {
2521                         if (loops == 0) {
2522                                 /*
2523                                  * btrfs_find_ref_cluster looped. let's do one
2524                                  * more cycle. if we don't run any delayed ref
2525                                  * during that cycle (because we can't because
2526                                  * all of them are blocked), bail out.
2527                                  */
2528                                 loops = 1;
2529                         } else {
2530                                 /*
2531                                  * no runnable refs left, stop trying
2532                                  */
2533                                 BUG_ON(run_all);
2534                                 break;
2535                         }
2536                 }
2537                 if (ret) {
2538                         /* refs were run, let's reset staleness detection */
2539                         loops = 0;
2540                 }
2541         }
2542
2543         if (run_all) {
2544                 node = rb_first(&delayed_refs->root);
2545                 if (!node)
2546                         goto out;
2547                 count = (unsigned long)-1;
2548
2549                 while (node) {
2550                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2551                                        rb_node);
2552                         if (btrfs_delayed_ref_is_head(ref)) {
2553                                 struct btrfs_delayed_ref_head *head;
2554
2555                                 head = btrfs_delayed_node_to_head(ref);
2556                                 atomic_inc(&ref->refs);
2557
2558                                 spin_unlock(&delayed_refs->lock);
2559                                 /*
2560                                  * Mutex was contended, block until it's
2561                                  * released and try again
2562                                  */
2563                                 mutex_lock(&head->mutex);
2564                                 mutex_unlock(&head->mutex);
2565
2566                                 btrfs_put_delayed_ref(ref);
2567                                 cond_resched();
2568                                 goto again;
2569                         }
2570                         node = rb_next(node);
2571                 }
2572                 spin_unlock(&delayed_refs->lock);
2573                 schedule_timeout(1);
2574                 goto again;
2575         }
2576 out:
2577         spin_unlock(&delayed_refs->lock);
2578         assert_qgroups_uptodate(trans);
2579         return 0;
2580 }
2581
2582 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2583                                 struct btrfs_root *root,
2584                                 u64 bytenr, u64 num_bytes, u64 flags,
2585                                 int is_data)
2586 {
2587         struct btrfs_delayed_extent_op *extent_op;
2588         int ret;
2589
2590         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2591         if (!extent_op)
2592                 return -ENOMEM;
2593
2594         extent_op->flags_to_set = flags;
2595         extent_op->update_flags = 1;
2596         extent_op->update_key = 0;
2597         extent_op->is_data = is_data ? 1 : 0;
2598
2599         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2600                                           num_bytes, extent_op);
2601         if (ret)
2602                 kfree(extent_op);
2603         return ret;
2604 }
2605
2606 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2607                                       struct btrfs_root *root,
2608                                       struct btrfs_path *path,
2609                                       u64 objectid, u64 offset, u64 bytenr)
2610 {
2611         struct btrfs_delayed_ref_head *head;
2612         struct btrfs_delayed_ref_node *ref;
2613         struct btrfs_delayed_data_ref *data_ref;
2614         struct btrfs_delayed_ref_root *delayed_refs;
2615         struct rb_node *node;
2616         int ret = 0;
2617
2618         ret = -ENOENT;
2619         delayed_refs = &trans->transaction->delayed_refs;
2620         spin_lock(&delayed_refs->lock);
2621         head = btrfs_find_delayed_ref_head(trans, bytenr);
2622         if (!head)
2623                 goto out;
2624
2625         if (!mutex_trylock(&head->mutex)) {
2626                 atomic_inc(&head->node.refs);
2627                 spin_unlock(&delayed_refs->lock);
2628
2629                 btrfs_release_path(path);
2630
2631                 /*
2632                  * Mutex was contended, block until it's released and let
2633                  * caller try again
2634                  */
2635                 mutex_lock(&head->mutex);
2636                 mutex_unlock(&head->mutex);
2637                 btrfs_put_delayed_ref(&head->node);
2638                 return -EAGAIN;
2639         }
2640
2641         node = rb_prev(&head->node.rb_node);
2642         if (!node)
2643                 goto out_unlock;
2644
2645         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2646
2647         if (ref->bytenr != bytenr)
2648                 goto out_unlock;
2649
2650         ret = 1;
2651         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2652                 goto out_unlock;
2653
2654         data_ref = btrfs_delayed_node_to_data_ref(ref);
2655
2656         node = rb_prev(node);
2657         if (node) {
2658                 int seq = ref->seq;
2659
2660                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2661                 if (ref->bytenr == bytenr && ref->seq == seq)
2662                         goto out_unlock;
2663         }
2664
2665         if (data_ref->root != root->root_key.objectid ||
2666             data_ref->objectid != objectid || data_ref->offset != offset)
2667                 goto out_unlock;
2668
2669         ret = 0;
2670 out_unlock:
2671         mutex_unlock(&head->mutex);
2672 out:
2673         spin_unlock(&delayed_refs->lock);
2674         return ret;
2675 }
2676
2677 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2678                                         struct btrfs_root *root,
2679                                         struct btrfs_path *path,
2680                                         u64 objectid, u64 offset, u64 bytenr)
2681 {
2682         struct btrfs_root *extent_root = root->fs_info->extent_root;
2683         struct extent_buffer *leaf;
2684         struct btrfs_extent_data_ref *ref;
2685         struct btrfs_extent_inline_ref *iref;
2686         struct btrfs_extent_item *ei;
2687         struct btrfs_key key;
2688         u32 item_size;
2689         int ret;
2690
2691         key.objectid = bytenr;
2692         key.offset = (u64)-1;
2693         key.type = BTRFS_EXTENT_ITEM_KEY;
2694
2695         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2696         if (ret < 0)
2697                 goto out;
2698         BUG_ON(ret == 0); /* Corruption */
2699
2700         ret = -ENOENT;
2701         if (path->slots[0] == 0)
2702                 goto out;
2703
2704         path->slots[0]--;
2705         leaf = path->nodes[0];
2706         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2707
2708         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2709                 goto out;
2710
2711         ret = 1;
2712         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2713 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2714         if (item_size < sizeof(*ei)) {
2715                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2716                 goto out;
2717         }
2718 #endif
2719         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2720
2721         if (item_size != sizeof(*ei) +
2722             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2723                 goto out;
2724
2725         if (btrfs_extent_generation(leaf, ei) <=
2726             btrfs_root_last_snapshot(&root->root_item))
2727                 goto out;
2728
2729         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2730         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2731             BTRFS_EXTENT_DATA_REF_KEY)
2732                 goto out;
2733
2734         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2735         if (btrfs_extent_refs(leaf, ei) !=
2736             btrfs_extent_data_ref_count(leaf, ref) ||
2737             btrfs_extent_data_ref_root(leaf, ref) !=
2738             root->root_key.objectid ||
2739             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2740             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2741                 goto out;
2742
2743         ret = 0;
2744 out:
2745         return ret;
2746 }
2747
2748 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2749                           struct btrfs_root *root,
2750                           u64 objectid, u64 offset, u64 bytenr)
2751 {
2752         struct btrfs_path *path;
2753         int ret;
2754         int ret2;
2755
2756         path = btrfs_alloc_path();
2757         if (!path)
2758                 return -ENOENT;
2759
2760         do {
2761                 ret = check_committed_ref(trans, root, path, objectid,
2762                                           offset, bytenr);
2763                 if (ret && ret != -ENOENT)
2764                         goto out;
2765
2766                 ret2 = check_delayed_ref(trans, root, path, objectid,
2767                                          offset, bytenr);
2768         } while (ret2 == -EAGAIN);
2769
2770         if (ret2 && ret2 != -ENOENT) {
2771                 ret = ret2;
2772                 goto out;
2773         }
2774
2775         if (ret != -ENOENT || ret2 != -ENOENT)
2776                 ret = 0;
2777 out:
2778         btrfs_free_path(path);
2779         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2780                 WARN_ON(ret > 0);
2781         return ret;
2782 }
2783
2784 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2785                            struct btrfs_root *root,
2786                            struct extent_buffer *buf,
2787                            int full_backref, int inc, int for_cow)
2788 {
2789         u64 bytenr;
2790         u64 num_bytes;
2791         u64 parent;
2792         u64 ref_root;
2793         u32 nritems;
2794         struct btrfs_key key;
2795         struct btrfs_file_extent_item *fi;
2796         int i;
2797         int level;
2798         int ret = 0;
2799         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2800                             u64, u64, u64, u64, u64, u64, int);
2801
2802         ref_root = btrfs_header_owner(buf);
2803         nritems = btrfs_header_nritems(buf);
2804         level = btrfs_header_level(buf);
2805
2806         if (!root->ref_cows && level == 0)
2807                 return 0;
2808
2809         if (inc)
2810                 process_func = btrfs_inc_extent_ref;
2811         else
2812                 process_func = btrfs_free_extent;
2813
2814         if (full_backref)
2815                 parent = buf->start;
2816         else
2817                 parent = 0;
2818
2819         for (i = 0; i < nritems; i++) {
2820                 if (level == 0) {
2821                         btrfs_item_key_to_cpu(buf, &key, i);
2822                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2823                                 continue;
2824                         fi = btrfs_item_ptr(buf, i,
2825                                             struct btrfs_file_extent_item);
2826                         if (btrfs_file_extent_type(buf, fi) ==
2827                             BTRFS_FILE_EXTENT_INLINE)
2828                                 continue;
2829                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2830                         if (bytenr == 0)
2831                                 continue;
2832
2833                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2834                         key.offset -= btrfs_file_extent_offset(buf, fi);
2835                         ret = process_func(trans, root, bytenr, num_bytes,
2836                                            parent, ref_root, key.objectid,
2837                                            key.offset, for_cow);
2838                         if (ret)
2839                                 goto fail;
2840                 } else {
2841                         bytenr = btrfs_node_blockptr(buf, i);
2842                         num_bytes = btrfs_level_size(root, level - 1);
2843                         ret = process_func(trans, root, bytenr, num_bytes,
2844                                            parent, ref_root, level - 1, 0,
2845                                            for_cow);
2846                         if (ret)
2847                                 goto fail;
2848                 }
2849         }
2850         return 0;
2851 fail:
2852         return ret;
2853 }
2854
2855 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2856                   struct extent_buffer *buf, int full_backref, int for_cow)
2857 {
2858         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2859 }
2860
2861 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2862                   struct extent_buffer *buf, int full_backref, int for_cow)
2863 {
2864         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2865 }
2866
2867 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2868                                  struct btrfs_root *root,
2869                                  struct btrfs_path *path,
2870                                  struct btrfs_block_group_cache *cache)
2871 {
2872         int ret;
2873         struct btrfs_root *extent_root = root->fs_info->extent_root;
2874         unsigned long bi;
2875         struct extent_buffer *leaf;
2876
2877         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2878         if (ret < 0)
2879                 goto fail;
2880         BUG_ON(ret); /* Corruption */
2881
2882         leaf = path->nodes[0];
2883         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2884         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2885         btrfs_mark_buffer_dirty(leaf);
2886         btrfs_release_path(path);
2887 fail:
2888         if (ret) {
2889                 btrfs_abort_transaction(trans, root, ret);
2890                 return ret;
2891         }
2892         return 0;
2893
2894 }
2895
2896 static struct btrfs_block_group_cache *
2897 next_block_group(struct btrfs_root *root,
2898                  struct btrfs_block_group_cache *cache)
2899 {
2900         struct rb_node *node;
2901         spin_lock(&root->fs_info->block_group_cache_lock);
2902         node = rb_next(&cache->cache_node);
2903         btrfs_put_block_group(cache);
2904         if (node) {
2905                 cache = rb_entry(node, struct btrfs_block_group_cache,
2906                                  cache_node);
2907                 btrfs_get_block_group(cache);
2908         } else
2909                 cache = NULL;
2910         spin_unlock(&root->fs_info->block_group_cache_lock);
2911         return cache;
2912 }
2913
2914 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2915                             struct btrfs_trans_handle *trans,
2916                             struct btrfs_path *path)
2917 {
2918         struct btrfs_root *root = block_group->fs_info->tree_root;
2919         struct inode *inode = NULL;
2920         u64 alloc_hint = 0;
2921         int dcs = BTRFS_DC_ERROR;
2922         int num_pages = 0;
2923         int retries = 0;
2924         int ret = 0;
2925
2926         /*
2927          * If this block group is smaller than 100 megs don't bother caching the
2928          * block group.
2929          */
2930         if (block_group->key.offset < (100 * 1024 * 1024)) {
2931                 spin_lock(&block_group->lock);
2932                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2933                 spin_unlock(&block_group->lock);
2934                 return 0;
2935         }
2936
2937 again:
2938         inode = lookup_free_space_inode(root, block_group, path);
2939         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2940                 ret = PTR_ERR(inode);
2941                 btrfs_release_path(path);
2942                 goto out;
2943         }
2944
2945         if (IS_ERR(inode)) {
2946                 BUG_ON(retries);
2947                 retries++;
2948
2949                 if (block_group->ro)
2950                         goto out_free;
2951
2952                 ret = create_free_space_inode(root, trans, block_group, path);
2953                 if (ret)
2954                         goto out_free;
2955                 goto again;
2956         }
2957
2958         /* We've already setup this transaction, go ahead and exit */
2959         if (block_group->cache_generation == trans->transid &&
2960             i_size_read(inode)) {
2961                 dcs = BTRFS_DC_SETUP;
2962                 goto out_put;
2963         }
2964
2965         /*
2966          * We want to set the generation to 0, that way if anything goes wrong
2967          * from here on out we know not to trust this cache when we load up next
2968          * time.
2969          */
2970         BTRFS_I(inode)->generation = 0;
2971         ret = btrfs_update_inode(trans, root, inode);
2972         WARN_ON(ret);
2973
2974         if (i_size_read(inode) > 0) {
2975                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2976                                                       inode);
2977                 if (ret)
2978                         goto out_put;
2979         }
2980
2981         spin_lock(&block_group->lock);
2982         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2983             !btrfs_test_opt(root, SPACE_CACHE)) {
2984                 /*
2985                  * don't bother trying to write stuff out _if_
2986                  * a) we're not cached,
2987                  * b) we're with nospace_cache mount option.
2988                  */
2989                 dcs = BTRFS_DC_WRITTEN;
2990                 spin_unlock(&block_group->lock);
2991                 goto out_put;
2992         }
2993         spin_unlock(&block_group->lock);
2994
2995         /*
2996          * Try to preallocate enough space based on how big the block group is.
2997          * Keep in mind this has to include any pinned space which could end up
2998          * taking up quite a bit since it's not folded into the other space
2999          * cache.
3000          */
3001         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3002         if (!num_pages)
3003                 num_pages = 1;
3004
3005         num_pages *= 16;
3006         num_pages *= PAGE_CACHE_SIZE;
3007
3008         ret = btrfs_check_data_free_space(inode, num_pages);
3009         if (ret)
3010                 goto out_put;
3011
3012         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3013                                               num_pages, num_pages,
3014                                               &alloc_hint);
3015         if (!ret)
3016                 dcs = BTRFS_DC_SETUP;
3017         btrfs_free_reserved_data_space(inode, num_pages);
3018
3019 out_put:
3020         iput(inode);
3021 out_free:
3022         btrfs_release_path(path);
3023 out:
3024         spin_lock(&block_group->lock);
3025         if (!ret && dcs == BTRFS_DC_SETUP)
3026                 block_group->cache_generation = trans->transid;
3027         block_group->disk_cache_state = dcs;
3028         spin_unlock(&block_group->lock);
3029
3030         return ret;
3031 }
3032
3033 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3034                                    struct btrfs_root *root)
3035 {
3036         struct btrfs_block_group_cache *cache;
3037         int err = 0;
3038         struct btrfs_path *path;
3039         u64 last = 0;
3040
3041         path = btrfs_alloc_path();
3042         if (!path)
3043                 return -ENOMEM;
3044
3045 again:
3046         while (1) {
3047                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3048                 while (cache) {
3049                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3050                                 break;
3051                         cache = next_block_group(root, cache);
3052                 }
3053                 if (!cache) {
3054                         if (last == 0)
3055                                 break;
3056                         last = 0;
3057                         continue;
3058                 }
3059                 err = cache_save_setup(cache, trans, path);
3060                 last = cache->key.objectid + cache->key.offset;
3061                 btrfs_put_block_group(cache);
3062         }
3063
3064         while (1) {
3065                 if (last == 0) {
3066                         err = btrfs_run_delayed_refs(trans, root,
3067                                                      (unsigned long)-1);
3068                         if (err) /* File system offline */
3069                                 goto out;
3070                 }
3071
3072                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3073                 while (cache) {
3074                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3075                                 btrfs_put_block_group(cache);
3076                                 goto again;
3077                         }
3078
3079                         if (cache->dirty)
3080                                 break;
3081                         cache = next_block_group(root, cache);
3082                 }
3083                 if (!cache) {
3084                         if (last == 0)
3085                                 break;
3086                         last = 0;
3087                         continue;
3088                 }
3089
3090                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3091                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3092                 cache->dirty = 0;
3093                 last = cache->key.objectid + cache->key.offset;
3094
3095                 err = write_one_cache_group(trans, root, path, cache);
3096                 if (err) /* File system offline */
3097                         goto out;
3098
3099                 btrfs_put_block_group(cache);
3100         }
3101
3102         while (1) {
3103                 /*
3104                  * I don't think this is needed since we're just marking our
3105                  * preallocated extent as written, but just in case it can't
3106                  * hurt.
3107                  */
3108                 if (last == 0) {
3109                         err = btrfs_run_delayed_refs(trans, root,
3110                                                      (unsigned long)-1);
3111                         if (err) /* File system offline */
3112                                 goto out;
3113                 }
3114
3115                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3116                 while (cache) {
3117                         /*
3118                          * Really this shouldn't happen, but it could if we
3119                          * couldn't write the entire preallocated extent and
3120                          * splitting the extent resulted in a new block.
3121                          */
3122                         if (cache->dirty) {
3123                                 btrfs_put_block_group(cache);
3124                                 goto again;
3125                         }
3126                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3127                                 break;
3128                         cache = next_block_group(root, cache);
3129                 }
3130                 if (!cache) {
3131                         if (last == 0)
3132                                 break;
3133                         last = 0;
3134                         continue;
3135                 }
3136
3137                 err = btrfs_write_out_cache(root, trans, cache, path);
3138
3139                 /*
3140                  * If we didn't have an error then the cache state is still
3141                  * NEED_WRITE, so we can set it to WRITTEN.
3142                  */
3143                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3144                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3145                 last = cache->key.objectid + cache->key.offset;
3146                 btrfs_put_block_group(cache);
3147         }
3148 out:
3149
3150         btrfs_free_path(path);
3151         return err;
3152 }
3153
3154 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3155 {
3156         struct btrfs_block_group_cache *block_group;
3157         int readonly = 0;
3158
3159         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3160         if (!block_group || block_group->ro)
3161                 readonly = 1;
3162         if (block_group)
3163                 btrfs_put_block_group(block_group);
3164         return readonly;
3165 }
3166
3167 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3168                              u64 total_bytes, u64 bytes_used,
3169                              struct btrfs_space_info **space_info)
3170 {
3171         struct btrfs_space_info *found;
3172         int i;
3173         int factor;
3174
3175         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3176                      BTRFS_BLOCK_GROUP_RAID10))
3177                 factor = 2;
3178         else
3179                 factor = 1;
3180
3181         found = __find_space_info(info, flags);
3182         if (found) {
3183                 spin_lock(&found->lock);
3184                 found->total_bytes += total_bytes;
3185                 found->disk_total += total_bytes * factor;
3186                 found->bytes_used += bytes_used;
3187                 found->disk_used += bytes_used * factor;
3188                 found->full = 0;
3189                 spin_unlock(&found->lock);
3190                 *space_info = found;
3191                 return 0;
3192         }
3193         found = kzalloc(sizeof(*found), GFP_NOFS);
3194         if (!found)
3195                 return -ENOMEM;
3196
3197         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3198                 INIT_LIST_HEAD(&found->block_groups[i]);
3199         init_rwsem(&found->groups_sem);
3200         spin_lock_init(&found->lock);
3201         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3202         found->total_bytes = total_bytes;
3203         found->disk_total = total_bytes * factor;
3204         found->bytes_used = bytes_used;
3205         found->disk_used = bytes_used * factor;
3206         found->bytes_pinned = 0;
3207         found->bytes_reserved = 0;
3208         found->bytes_readonly = 0;
3209         found->bytes_may_use = 0;
3210         found->full = 0;
3211         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3212         found->chunk_alloc = 0;
3213         found->flush = 0;
3214         init_waitqueue_head(&found->wait);
3215         *space_info = found;
3216         list_add_rcu(&found->list, &info->space_info);
3217         if (flags & BTRFS_BLOCK_GROUP_DATA)
3218                 info->data_sinfo = found;
3219         return 0;
3220 }
3221
3222 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3223 {
3224         u64 extra_flags = chunk_to_extended(flags) &
3225                                 BTRFS_EXTENDED_PROFILE_MASK;
3226
3227         if (flags & BTRFS_BLOCK_GROUP_DATA)
3228                 fs_info->avail_data_alloc_bits |= extra_flags;
3229         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3230                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3231         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3232                 fs_info->avail_system_alloc_bits |= extra_flags;
3233 }
3234
3235 /*
3236  * returns target flags in extended format or 0 if restripe for this
3237  * chunk_type is not in progress
3238  *
3239  * should be called with either volume_mutex or balance_lock held
3240  */
3241 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3242 {
3243         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3244         u64 target = 0;
3245
3246         if (!bctl)
3247                 return 0;
3248
3249         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3250             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3251                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3252         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3253                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3254                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3255         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3256                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3257                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3258         }
3259
3260         return target;
3261 }
3262
3263 /*
3264  * @flags: available profiles in extended format (see ctree.h)
3265  *
3266  * Returns reduced profile in chunk format.  If profile changing is in
3267  * progress (either running or paused) picks the target profile (if it's
3268  * already available), otherwise falls back to plain reducing.
3269  */
3270 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3271 {
3272         /*
3273          * we add in the count of missing devices because we want
3274          * to make sure that any RAID levels on a degraded FS
3275          * continue to be honored.
3276          */
3277         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3278                 root->fs_info->fs_devices->missing_devices;
3279         u64 target;
3280
3281         /*
3282          * see if restripe for this chunk_type is in progress, if so
3283          * try to reduce to the target profile
3284          */
3285         spin_lock(&root->fs_info->balance_lock);
3286         target = get_restripe_target(root->fs_info, flags);
3287         if (target) {
3288                 /* pick target profile only if it's already available */
3289                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3290                         spin_unlock(&root->fs_info->balance_lock);
3291                         return extended_to_chunk(target);
3292                 }
3293         }
3294         spin_unlock(&root->fs_info->balance_lock);
3295
3296         if (num_devices == 1)
3297                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3298         if (num_devices < 4)
3299                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3300
3301         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3302             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3303                       BTRFS_BLOCK_GROUP_RAID10))) {
3304                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3305         }
3306
3307         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3308             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3309                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3310         }
3311
3312         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3313             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3314              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3315              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3316                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3317         }
3318
3319         return extended_to_chunk(flags);
3320 }
3321
3322 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3323 {
3324         if (flags & BTRFS_BLOCK_GROUP_DATA)
3325                 flags |= root->fs_info->avail_data_alloc_bits;
3326         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3327                 flags |= root->fs_info->avail_system_alloc_bits;
3328         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3329                 flags |= root->fs_info->avail_metadata_alloc_bits;
3330
3331         return btrfs_reduce_alloc_profile(root, flags);
3332 }
3333
3334 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3335 {
3336         u64 flags;
3337
3338         if (data)
3339                 flags = BTRFS_BLOCK_GROUP_DATA;
3340         else if (root == root->fs_info->chunk_root)
3341                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3342         else
3343                 flags = BTRFS_BLOCK_GROUP_METADATA;
3344
3345         return get_alloc_profile(root, flags);
3346 }
3347
3348 /*
3349  * This will check the space that the inode allocates from to make sure we have
3350  * enough space for bytes.
3351  */
3352 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3353 {
3354         struct btrfs_space_info *data_sinfo;
3355         struct btrfs_root *root = BTRFS_I(inode)->root;
3356         struct btrfs_fs_info *fs_info = root->fs_info;
3357         u64 used;
3358         int ret = 0, committed = 0, alloc_chunk = 1;
3359
3360         /* make sure bytes are sectorsize aligned */
3361         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3362
3363         if (root == root->fs_info->tree_root ||
3364             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3365                 alloc_chunk = 0;
3366                 committed = 1;
3367         }
3368
3369         data_sinfo = fs_info->data_sinfo;
3370         if (!data_sinfo)
3371                 goto alloc;
3372
3373 again:
3374         /* make sure we have enough space to handle the data first */
3375         spin_lock(&data_sinfo->lock);
3376         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3377                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3378                 data_sinfo->bytes_may_use;
3379
3380         if (used + bytes > data_sinfo->total_bytes) {
3381                 struct btrfs_trans_handle *trans;
3382
3383                 /*
3384                  * if we don't have enough free bytes in this space then we need
3385                  * to alloc a new chunk.
3386                  */
3387                 if (!data_sinfo->full && alloc_chunk) {
3388                         u64 alloc_target;
3389
3390                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3391                         spin_unlock(&data_sinfo->lock);
3392 alloc:
3393                         alloc_target = btrfs_get_alloc_profile(root, 1);
3394                         trans = btrfs_join_transaction(root);
3395                         if (IS_ERR(trans))
3396                                 return PTR_ERR(trans);
3397
3398                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3399                                              bytes + 2 * 1024 * 1024,
3400                                              alloc_target,
3401                                              CHUNK_ALLOC_NO_FORCE);
3402                         btrfs_end_transaction(trans, root);
3403                         if (ret < 0) {
3404                                 if (ret != -ENOSPC)
3405                                         return ret;
3406                                 else
3407                                         goto commit_trans;
3408                         }
3409
3410                         if (!data_sinfo)
3411                                 data_sinfo = fs_info->data_sinfo;
3412
3413                         goto again;
3414                 }
3415
3416                 /*
3417                  * If we have less pinned bytes than we want to allocate then
3418                  * don't bother committing the transaction, it won't help us.
3419                  */
3420                 if (data_sinfo->bytes_pinned < bytes)
3421                         committed = 1;
3422                 spin_unlock(&data_sinfo->lock);
3423
3424                 /* commit the current transaction and try again */
3425 commit_trans:
3426                 if (!committed &&
3427                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3428                         committed = 1;
3429                         trans = btrfs_join_transaction(root);
3430                         if (IS_ERR(trans))
3431                                 return PTR_ERR(trans);
3432                         ret = btrfs_commit_transaction(trans, root);
3433                         if (ret)
3434                                 return ret;
3435                         goto again;
3436                 }
3437
3438                 return -ENOSPC;
3439         }
3440         data_sinfo->bytes_may_use += bytes;
3441         trace_btrfs_space_reservation(root->fs_info, "space_info",
3442                                       data_sinfo->flags, bytes, 1);
3443         spin_unlock(&data_sinfo->lock);
3444
3445         return 0;
3446 }
3447
3448 /*
3449  * Called if we need to clear a data reservation for this inode.
3450  */
3451 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3452 {
3453         struct btrfs_root *root = BTRFS_I(inode)->root;
3454         struct btrfs_space_info *data_sinfo;
3455
3456         /* make sure bytes are sectorsize aligned */
3457         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3458
3459         data_sinfo = root->fs_info->data_sinfo;
3460         spin_lock(&data_sinfo->lock);
3461         data_sinfo->bytes_may_use -= bytes;
3462         trace_btrfs_space_reservation(root->fs_info, "space_info",
3463                                       data_sinfo->flags, bytes, 0);
3464         spin_unlock(&data_sinfo->lock);
3465 }
3466
3467 static void force_metadata_allocation(struct btrfs_fs_info *info)
3468 {
3469         struct list_head *head = &info->space_info;
3470         struct btrfs_space_info *found;
3471
3472         rcu_read_lock();
3473         list_for_each_entry_rcu(found, head, list) {
3474                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3475                         found->force_alloc = CHUNK_ALLOC_FORCE;
3476         }
3477         rcu_read_unlock();
3478 }
3479
3480 static int should_alloc_chunk(struct btrfs_root *root,
3481                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3482                               int force)
3483 {
3484         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3485         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3486         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3487         u64 thresh;
3488
3489         if (force == CHUNK_ALLOC_FORCE)
3490                 return 1;
3491
3492         /*
3493          * We need to take into account the global rsv because for all intents
3494          * and purposes it's used space.  Don't worry about locking the
3495          * global_rsv, it doesn't change except when the transaction commits.
3496          */
3497         num_allocated += global_rsv->size;
3498
3499         /*
3500          * in limited mode, we want to have some free space up to
3501          * about 1% of the FS size.
3502          */
3503         if (force == CHUNK_ALLOC_LIMITED) {
3504                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3505                 thresh = max_t(u64, 64 * 1024 * 1024,
3506                                div_factor_fine(thresh, 1));
3507
3508                 if (num_bytes - num_allocated < thresh)
3509                         return 1;
3510         }
3511         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3512
3513         /* 256MB or 2% of the FS */
3514         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3515         /* system chunks need a much small threshold */
3516         if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
3517                 thresh = 32 * 1024 * 1024;
3518
3519         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3520                 return 0;
3521         return 1;
3522 }
3523
3524 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3525 {
3526         u64 num_dev;
3527
3528         if (type & BTRFS_BLOCK_GROUP_RAID10 ||
3529             type & BTRFS_BLOCK_GROUP_RAID0)
3530                 num_dev = root->fs_info->fs_devices->rw_devices;
3531         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3532                 num_dev = 2;
3533         else
3534                 num_dev = 1;    /* DUP or single */
3535
3536         /* metadata for updaing devices and chunk tree */
3537         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3538 }
3539
3540 static void check_system_chunk(struct btrfs_trans_handle *trans,
3541                                struct btrfs_root *root, u64 type)
3542 {
3543         struct btrfs_space_info *info;
3544         u64 left;
3545         u64 thresh;
3546
3547         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3548         spin_lock(&info->lock);
3549         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3550                 info->bytes_reserved - info->bytes_readonly;
3551         spin_unlock(&info->lock);
3552
3553         thresh = get_system_chunk_thresh(root, type);
3554         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3555                 printk(KERN_INFO "left=%llu, need=%llu, flags=%llu\n",
3556                        left, thresh, type);
3557                 dump_space_info(info, 0, 0);
3558         }
3559
3560         if (left < thresh) {
3561                 u64 flags;
3562
3563                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3564                 btrfs_alloc_chunk(trans, root, flags);
3565         }
3566 }
3567
3568 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3569                           struct btrfs_root *extent_root, u64 alloc_bytes,
3570                           u64 flags, int force)
3571 {
3572         struct btrfs_space_info *space_info;
3573         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3574         int wait_for_alloc = 0;
3575         int ret = 0;
3576
3577         space_info = __find_space_info(extent_root->fs_info, flags);
3578         if (!space_info) {
3579                 ret = update_space_info(extent_root->fs_info, flags,
3580                                         0, 0, &space_info);
3581                 BUG_ON(ret); /* -ENOMEM */
3582         }
3583         BUG_ON(!space_info); /* Logic error */
3584
3585 again:
3586         spin_lock(&space_info->lock);
3587         if (force < space_info->force_alloc)
3588                 force = space_info->force_alloc;
3589         if (space_info->full) {
3590                 spin_unlock(&space_info->lock);
3591                 return 0;
3592         }
3593
3594         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3595                 spin_unlock(&space_info->lock);
3596                 return 0;
3597         } else if (space_info->chunk_alloc) {
3598                 wait_for_alloc = 1;
3599         } else {
3600                 space_info->chunk_alloc = 1;
3601         }
3602
3603         spin_unlock(&space_info->lock);
3604
3605         mutex_lock(&fs_info->chunk_mutex);
3606
3607         /*
3608          * The chunk_mutex is held throughout the entirety of a chunk
3609          * allocation, so once we've acquired the chunk_mutex we know that the
3610          * other guy is done and we need to recheck and see if we should
3611          * allocate.
3612          */
3613         if (wait_for_alloc) {
3614                 mutex_unlock(&fs_info->chunk_mutex);
3615                 wait_for_alloc = 0;
3616                 goto again;
3617         }
3618
3619         /*
3620          * If we have mixed data/metadata chunks we want to make sure we keep
3621          * allocating mixed chunks instead of individual chunks.
3622          */
3623         if (btrfs_mixed_space_info(space_info))
3624                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3625
3626         /*
3627          * if we're doing a data chunk, go ahead and make sure that
3628          * we keep a reasonable number of metadata chunks allocated in the
3629          * FS as well.
3630          */
3631         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3632                 fs_info->data_chunk_allocations++;
3633                 if (!(fs_info->data_chunk_allocations %
3634                       fs_info->metadata_ratio))
3635                         force_metadata_allocation(fs_info);
3636         }
3637
3638         /*
3639          * Check if we have enough space in SYSTEM chunk because we may need
3640          * to update devices.
3641          */
3642         check_system_chunk(trans, extent_root, flags);
3643
3644         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3645         if (ret < 0 && ret != -ENOSPC)
3646                 goto out;
3647
3648         spin_lock(&space_info->lock);
3649         if (ret)
3650                 space_info->full = 1;
3651         else
3652                 ret = 1;
3653
3654         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3655         space_info->chunk_alloc = 0;
3656         spin_unlock(&space_info->lock);
3657 out:
3658         mutex_unlock(&fs_info->chunk_mutex);
3659         return ret;
3660 }
3661
3662 /*
3663  * shrink metadata reservation for delalloc
3664  */
3665 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3666                             bool wait_ordered)
3667 {
3668         struct btrfs_block_rsv *block_rsv;
3669         struct btrfs_space_info *space_info;
3670         struct btrfs_trans_handle *trans;
3671         u64 delalloc_bytes;
3672         u64 max_reclaim;
3673         long time_left;
3674         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3675         int loops = 0;
3676
3677         trans = (struct btrfs_trans_handle *)current->journal_info;
3678         block_rsv = &root->fs_info->delalloc_block_rsv;
3679         space_info = block_rsv->space_info;
3680
3681         smp_mb();
3682         delalloc_bytes = root->fs_info->delalloc_bytes;
3683         if (delalloc_bytes == 0) {
3684                 if (trans)
3685                         return;
3686                 btrfs_wait_ordered_extents(root, 0, 0);
3687                 return;
3688         }
3689
3690         while (delalloc_bytes && loops < 3) {
3691                 max_reclaim = min(delalloc_bytes, to_reclaim);
3692                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3693                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3694                                                WB_REASON_FS_FREE_SPACE);
3695
3696                 spin_lock(&space_info->lock);
3697                 if (space_info->bytes_used + space_info->bytes_reserved +
3698                     space_info->bytes_pinned + space_info->bytes_readonly +
3699                     space_info->bytes_may_use + orig <=
3700                     space_info->total_bytes) {
3701                         spin_unlock(&space_info->lock);
3702                         break;
3703                 }
3704                 spin_unlock(&space_info->lock);
3705
3706                 loops++;
3707                 if (wait_ordered && !trans) {
3708                         btrfs_wait_ordered_extents(root, 0, 0);
3709                 } else {
3710                         time_left = schedule_timeout_killable(1);
3711                         if (time_left)
3712                                 break;
3713                 }
3714                 smp_mb();
3715                 delalloc_bytes = root->fs_info->delalloc_bytes;
3716         }
3717 }
3718
3719 /**
3720  * maybe_commit_transaction - possibly commit the transaction if its ok to
3721  * @root - the root we're allocating for
3722  * @bytes - the number of bytes we want to reserve
3723  * @force - force the commit
3724  *
3725  * This will check to make sure that committing the transaction will actually
3726  * get us somewhere and then commit the transaction if it does.  Otherwise it
3727  * will return -ENOSPC.
3728  */
3729 static int may_commit_transaction(struct btrfs_root *root,
3730                                   struct btrfs_space_info *space_info,
3731                                   u64 bytes, int force)
3732 {
3733         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3734         struct btrfs_trans_handle *trans;
3735
3736         trans = (struct btrfs_trans_handle *)current->journal_info;
3737         if (trans)
3738                 return -EAGAIN;
3739
3740         if (force)
3741                 goto commit;
3742
3743         /* See if there is enough pinned space to make this reservation */
3744         spin_lock(&space_info->lock);
3745         if (space_info->bytes_pinned >= bytes) {
3746                 spin_unlock(&space_info->lock);
3747                 goto commit;
3748         }
3749         spin_unlock(&space_info->lock);
3750
3751         /*
3752          * See if there is some space in the delayed insertion reservation for
3753          * this reservation.
3754          */
3755         if (space_info != delayed_rsv->space_info)
3756                 return -ENOSPC;
3757
3758         spin_lock(&space_info->lock);
3759         spin_lock(&delayed_rsv->lock);
3760         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3761                 spin_unlock(&delayed_rsv->lock);
3762                 spin_unlock(&space_info->lock);
3763                 return -ENOSPC;
3764         }
3765         spin_unlock(&delayed_rsv->lock);
3766         spin_unlock(&space_info->lock);
3767
3768 commit:
3769         trans = btrfs_join_transaction(root);
3770         if (IS_ERR(trans))
3771                 return -ENOSPC;
3772
3773         return btrfs_commit_transaction(trans, root);
3774 }
3775
3776 enum flush_state {
3777         FLUSH_DELALLOC          =       1,
3778         FLUSH_DELALLOC_WAIT     =       2,
3779         FLUSH_DELAYED_ITEMS_NR  =       3,
3780         FLUSH_DELAYED_ITEMS     =       4,
3781         COMMIT_TRANS            =       5,
3782 };
3783
3784 static int flush_space(struct btrfs_root *root,
3785                        struct btrfs_space_info *space_info, u64 num_bytes,
3786                        u64 orig_bytes, int state)
3787 {
3788         struct btrfs_trans_handle *trans;
3789         int nr;
3790         int ret = 0;
3791
3792         switch (state) {
3793         case FLUSH_DELALLOC:
3794         case FLUSH_DELALLOC_WAIT:
3795                 shrink_delalloc(root, num_bytes, orig_bytes,
3796                                 state == FLUSH_DELALLOC_WAIT);
3797                 break;
3798         case FLUSH_DELAYED_ITEMS_NR:
3799         case FLUSH_DELAYED_ITEMS:
3800                 if (state == FLUSH_DELAYED_ITEMS_NR) {
3801                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
3802
3803                         nr = (int)div64_u64(num_bytes, bytes);
3804                         if (!nr)
3805                                 nr = 1;
3806                         nr *= 2;
3807                 } else {
3808                         nr = -1;
3809                 }
3810                 trans = btrfs_join_transaction(root);
3811                 if (IS_ERR(trans)) {
3812                         ret = PTR_ERR(trans);
3813                         break;
3814                 }
3815                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
3816                 btrfs_end_transaction(trans, root);
3817                 break;
3818         case COMMIT_TRANS:
3819                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3820                 break;
3821         default:
3822                 ret = -ENOSPC;
3823                 break;
3824         }
3825
3826         return ret;
3827 }
3828 /**
3829  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3830  * @root - the root we're allocating for
3831  * @block_rsv - the block_rsv we're allocating for
3832  * @orig_bytes - the number of bytes we want
3833  * @flush - wether or not we can flush to make our reservation
3834  *
3835  * This will reserve orgi_bytes number of bytes from the space info associated
3836  * with the block_rsv.  If there is not enough space it will make an attempt to
3837  * flush out space to make room.  It will do this by flushing delalloc if
3838  * possible or committing the transaction.  If flush is 0 then no attempts to
3839  * regain reservations will be made and this will fail if there is not enough
3840  * space already.
3841  */
3842 static int reserve_metadata_bytes(struct btrfs_root *root,
3843                                   struct btrfs_block_rsv *block_rsv,
3844                                   u64 orig_bytes, int flush)
3845 {
3846         struct btrfs_space_info *space_info = block_rsv->space_info;
3847         u64 used;
3848         u64 num_bytes = orig_bytes;
3849         int flush_state = FLUSH_DELALLOC;
3850         int ret = 0;
3851         bool flushing = false;
3852         bool committed = false;
3853
3854 again:
3855         ret = 0;
3856         spin_lock(&space_info->lock);
3857         /*
3858          * We only want to wait if somebody other than us is flushing and we are
3859          * actually alloed to flush.
3860          */
3861         while (flush && !flushing && space_info->flush) {
3862                 spin_unlock(&space_info->lock);
3863                 /*
3864                  * If we have a trans handle we can't wait because the flusher
3865                  * may have to commit the transaction, which would mean we would
3866                  * deadlock since we are waiting for the flusher to finish, but
3867                  * hold the current transaction open.
3868                  */
3869                 if (current->journal_info)
3870                         return -EAGAIN;
3871                 ret = wait_event_killable(space_info->wait, !space_info->flush);
3872                 /* Must have been killed, return */
3873                 if (ret)
3874                         return -EINTR;
3875
3876                 spin_lock(&space_info->lock);
3877         }
3878
3879         ret = -ENOSPC;
3880         used = space_info->bytes_used + space_info->bytes_reserved +
3881                 space_info->bytes_pinned + space_info->bytes_readonly +
3882                 space_info->bytes_may_use;
3883
3884         /*
3885          * The idea here is that we've not already over-reserved the block group
3886          * then we can go ahead and save our reservation first and then start
3887          * flushing if we need to.  Otherwise if we've already overcommitted
3888          * lets start flushing stuff first and then come back and try to make
3889          * our reservation.
3890          */
3891         if (used <= space_info->total_bytes) {
3892                 if (used + orig_bytes <= space_info->total_bytes) {
3893                         space_info->bytes_may_use += orig_bytes;
3894                         trace_btrfs_space_reservation(root->fs_info,
3895                                 "space_info", space_info->flags, orig_bytes, 1);
3896                         ret = 0;
3897                 } else {
3898                         /*
3899                          * Ok set num_bytes to orig_bytes since we aren't
3900                          * overocmmitted, this way we only try and reclaim what
3901                          * we need.
3902                          */
3903                         num_bytes = orig_bytes;
3904                 }
3905         } else {
3906                 /*
3907                  * Ok we're over committed, set num_bytes to the overcommitted
3908                  * amount plus the amount of bytes that we need for this
3909                  * reservation.
3910                  */
3911                 num_bytes = used - space_info->total_bytes +
3912                         (orig_bytes * 2);
3913         }
3914
3915         if (ret) {
3916                 u64 profile = btrfs_get_alloc_profile(root, 0);
3917                 u64 avail;
3918
3919                 /*
3920                  * If we have a lot of space that's pinned, don't bother doing
3921                  * the overcommit dance yet and just commit the transaction.
3922                  */
3923                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3924                 do_div(avail, 10);
3925                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3926                         space_info->flush = 1;
3927                         flushing = true;
3928                         spin_unlock(&space_info->lock);
3929                         ret = may_commit_transaction(root, space_info,
3930                                                      orig_bytes, 1);
3931                         if (ret)
3932                                 goto out;
3933                         committed = true;
3934                         goto again;
3935                 }
3936
3937                 spin_lock(&root->fs_info->free_chunk_lock);
3938                 avail = root->fs_info->free_chunk_space;
3939
3940                 /*
3941                  * If we have dup, raid1 or raid10 then only half of the free
3942                  * space is actually useable.
3943                  */
3944                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3945                                BTRFS_BLOCK_GROUP_RAID1 |
3946                                BTRFS_BLOCK_GROUP_RAID10))
3947                         avail >>= 1;
3948
3949                 /*
3950                  * If we aren't flushing don't let us overcommit too much, say
3951                  * 1/8th of the space.  If we can flush, let it overcommit up to
3952                  * 1/2 of the space.
3953                  */
3954                 if (flush)
3955                         avail >>= 3;
3956                 else
3957                         avail >>= 1;
3958                  spin_unlock(&root->fs_info->free_chunk_lock);
3959
3960                 if (used + num_bytes < space_info->total_bytes + avail) {
3961                         space_info->bytes_may_use += orig_bytes;
3962                         trace_btrfs_space_reservation(root->fs_info,
3963                                 "space_info", space_info->flags, orig_bytes, 1);
3964                         ret = 0;
3965                 }
3966         }
3967
3968         /*
3969          * Couldn't make our reservation, save our place so while we're trying
3970          * to reclaim space we can actually use it instead of somebody else
3971          * stealing it from us.
3972          */
3973         if (ret && flush) {
3974                 flushing = true;
3975                 space_info->flush = 1;
3976         }
3977
3978         spin_unlock(&space_info->lock);
3979
3980         if (!ret || !flush)
3981                 goto out;
3982
3983         ret = flush_space(root, space_info, num_bytes, orig_bytes,
3984                           flush_state);
3985         flush_state++;
3986         if (!ret)
3987                 goto again;
3988         else if (flush_state <= COMMIT_TRANS)
3989                 goto again;
3990
3991 out:
3992         if (flushing) {
3993                 spin_lock(&space_info->lock);
3994                 space_info->flush = 0;
3995                 wake_up_all(&space_info->wait);
3996                 spin_unlock(&space_info->lock);
3997         }
3998         return ret;
3999 }
4000
4001 static struct btrfs_block_rsv *get_block_rsv(
4002                                         const struct btrfs_trans_handle *trans,
4003                                         const struct btrfs_root *root)
4004 {
4005         struct btrfs_block_rsv *block_rsv = NULL;
4006
4007         if (root->ref_cows)
4008                 block_rsv = trans->block_rsv;
4009
4010         if (root == root->fs_info->csum_root && trans->adding_csums)
4011                 block_rsv = trans->block_rsv;
4012
4013         if (!block_rsv)
4014                 block_rsv = root->block_rsv;
4015
4016         if (!block_rsv)
4017                 block_rsv = &root->fs_info->empty_block_rsv;
4018
4019         return block_rsv;
4020 }
4021
4022 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4023                                u64 num_bytes)
4024 {
4025         int ret = -ENOSPC;
4026         spin_lock(&block_rsv->lock);
4027         if (block_rsv->reserved >= num_bytes) {
4028                 block_rsv->reserved -= num_bytes;
4029                 if (block_rsv->reserved < block_rsv->size)
4030                         block_rsv->full = 0;
4031                 ret = 0;
4032         }
4033         spin_unlock(&block_rsv->lock);
4034         return ret;
4035 }
4036
4037 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4038                                 u64 num_bytes, int update_size)
4039 {
4040         spin_lock(&block_rsv->lock);
4041         block_rsv->reserved += num_bytes;
4042         if (update_size)
4043                 block_rsv->size += num_bytes;
4044         else if (block_rsv->reserved >= block_rsv->size)
4045                 block_rsv->full = 1;
4046         spin_unlock(&block_rsv->lock);
4047 }
4048
4049 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4050                                     struct btrfs_block_rsv *block_rsv,
4051                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4052 {
4053         struct btrfs_space_info *space_info = block_rsv->space_info;
4054
4055         spin_lock(&block_rsv->lock);
4056         if (num_bytes == (u64)-1)
4057                 num_bytes = block_rsv->size;
4058         block_rsv->size -= num_bytes;
4059         if (block_rsv->reserved >= block_rsv->size) {
4060                 num_bytes = block_rsv->reserved - block_rsv->size;
4061                 block_rsv->reserved = block_rsv->size;
4062                 block_rsv->full = 1;
4063         } else {
4064                 num_bytes = 0;
4065         }
4066         spin_unlock(&block_rsv->lock);
4067
4068         if (num_bytes > 0) {
4069                 if (dest) {
4070                         spin_lock(&dest->lock);
4071                         if (!dest->full) {
4072                                 u64 bytes_to_add;
4073
4074                                 bytes_to_add = dest->size - dest->reserved;
4075                                 bytes_to_add = min(num_bytes, bytes_to_add);
4076                                 dest->reserved += bytes_to_add;
4077                                 if (dest->reserved >= dest->size)
4078                                         dest->full = 1;
4079                                 num_bytes -= bytes_to_add;
4080                         }
4081                         spin_unlock(&dest->lock);
4082                 }
4083                 if (num_bytes) {
4084                         spin_lock(&space_info->lock);
4085                         space_info->bytes_may_use -= num_bytes;
4086                         trace_btrfs_space_reservation(fs_info, "space_info",
4087                                         space_info->flags, num_bytes, 0);
4088                         space_info->reservation_progress++;
4089                         spin_unlock(&space_info->lock);
4090                 }
4091         }
4092 }
4093
4094 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4095                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4096 {
4097         int ret;
4098
4099         ret = block_rsv_use_bytes(src, num_bytes);
4100         if (ret)
4101                 return ret;
4102
4103         block_rsv_add_bytes(dst, num_bytes, 1);
4104         return 0;
4105 }
4106
4107 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
4108 {
4109         memset(rsv, 0, sizeof(*rsv));
4110         spin_lock_init(&rsv->lock);
4111 }
4112
4113 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
4114 {
4115         struct btrfs_block_rsv *block_rsv;
4116         struct btrfs_fs_info *fs_info = root->fs_info;
4117
4118         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4119         if (!block_rsv)
4120                 return NULL;
4121
4122         btrfs_init_block_rsv(block_rsv);
4123         block_rsv->space_info = __find_space_info(fs_info,
4124                                                   BTRFS_BLOCK_GROUP_METADATA);
4125         return block_rsv;
4126 }
4127
4128 void btrfs_free_block_rsv(struct btrfs_root *root,
4129                           struct btrfs_block_rsv *rsv)
4130 {
4131         btrfs_block_rsv_release(root, rsv, (u64)-1);
4132         kfree(rsv);
4133 }
4134
4135 static inline int __block_rsv_add(struct btrfs_root *root,
4136                                   struct btrfs_block_rsv *block_rsv,
4137                                   u64 num_bytes, int flush)
4138 {
4139         int ret;
4140
4141         if (num_bytes == 0)
4142                 return 0;
4143
4144         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4145         if (!ret) {
4146                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4147                 return 0;
4148         }
4149
4150         return ret;
4151 }
4152
4153 int btrfs_block_rsv_add(struct btrfs_root *root,
4154                         struct btrfs_block_rsv *block_rsv,
4155                         u64 num_bytes)
4156 {
4157         return __block_rsv_add(root, block_rsv, num_bytes, 1);
4158 }
4159
4160 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
4161                                 struct btrfs_block_rsv *block_rsv,
4162                                 u64 num_bytes)
4163 {
4164         return __block_rsv_add(root, block_rsv, num_bytes, 0);
4165 }
4166
4167 int btrfs_block_rsv_check(struct btrfs_root *root,
4168                           struct btrfs_block_rsv *block_rsv, int min_factor)
4169 {
4170         u64 num_bytes = 0;
4171         int ret = -ENOSPC;
4172
4173         if (!block_rsv)
4174                 return 0;
4175
4176         spin_lock(&block_rsv->lock);
4177         num_bytes = div_factor(block_rsv->size, min_factor);
4178         if (block_rsv->reserved >= num_bytes)
4179                 ret = 0;
4180         spin_unlock(&block_rsv->lock);
4181
4182         return ret;
4183 }
4184
4185 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4186                                            struct btrfs_block_rsv *block_rsv,
4187                                            u64 min_reserved, int flush)
4188 {
4189         u64 num_bytes = 0;
4190         int ret = -ENOSPC;
4191
4192         if (!block_rsv)
4193                 return 0;
4194
4195         spin_lock(&block_rsv->lock);
4196         num_bytes = min_reserved;
4197         if (block_rsv->reserved >= num_bytes)
4198                 ret = 0;
4199         else
4200                 num_bytes -= block_rsv->reserved;
4201         spin_unlock(&block_rsv->lock);
4202
4203         if (!ret)
4204                 return 0;
4205
4206         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4207         if (!ret) {
4208                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4209                 return 0;
4210         }
4211
4212         return ret;
4213 }
4214
4215 int btrfs_block_rsv_refill(struct btrfs_root *root,
4216                            struct btrfs_block_rsv *block_rsv,
4217                            u64 min_reserved)
4218 {
4219         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4220 }
4221
4222 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4223                                    struct btrfs_block_rsv *block_rsv,
4224                                    u64 min_reserved)
4225 {
4226         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4227 }
4228
4229 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4230                             struct btrfs_block_rsv *dst_rsv,
4231                             u64 num_bytes)
4232 {
4233         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4234 }
4235
4236 void btrfs_block_rsv_release(struct btrfs_root *root,
4237                              struct btrfs_block_rsv *block_rsv,
4238                              u64 num_bytes)
4239 {
4240         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4241         if (global_rsv->full || global_rsv == block_rsv ||
4242             block_rsv->space_info != global_rsv->space_info)
4243                 global_rsv = NULL;
4244         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4245                                 num_bytes);
4246 }
4247
4248 /*
4249  * helper to calculate size of global block reservation.
4250  * the desired value is sum of space used by extent tree,
4251  * checksum tree and root tree
4252  */
4253 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4254 {
4255         struct btrfs_space_info *sinfo;
4256         u64 num_bytes;
4257         u64 meta_used;
4258         u64 data_used;
4259         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4260
4261         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4262         spin_lock(&sinfo->lock);
4263         data_used = sinfo->bytes_used;
4264         spin_unlock(&sinfo->lock);
4265
4266         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4267         spin_lock(&sinfo->lock);
4268         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4269                 data_used = 0;
4270         meta_used = sinfo->bytes_used;
4271         spin_unlock(&sinfo->lock);
4272
4273         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4274                     csum_size * 2;
4275         num_bytes += div64_u64(data_used + meta_used, 50);
4276
4277         if (num_bytes * 3 > meta_used)
4278                 num_bytes = div64_u64(meta_used, 3);
4279
4280         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4281 }
4282
4283 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4284 {
4285         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4286         struct btrfs_space_info *sinfo = block_rsv->space_info;
4287         u64 num_bytes;
4288
4289         num_bytes = calc_global_metadata_size(fs_info);
4290
4291         spin_lock(&sinfo->lock);
4292         spin_lock(&block_rsv->lock);
4293
4294         block_rsv->size = num_bytes;
4295
4296         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4297                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4298                     sinfo->bytes_may_use;
4299
4300         if (sinfo->total_bytes > num_bytes) {
4301                 num_bytes = sinfo->total_bytes - num_bytes;
4302                 block_rsv->reserved += num_bytes;
4303                 sinfo->bytes_may_use += num_bytes;
4304                 trace_btrfs_space_reservation(fs_info, "space_info",
4305                                       sinfo->flags, num_bytes, 1);
4306         }
4307
4308         if (block_rsv->reserved >= block_rsv->size) {
4309                 num_bytes = block_rsv->reserved - block_rsv->size;
4310                 sinfo->bytes_may_use -= num_bytes;
4311                 trace_btrfs_space_reservation(fs_info, "space_info",
4312                                       sinfo->flags, num_bytes, 0);
4313                 sinfo->reservation_progress++;
4314                 block_rsv->reserved = block_rsv->size;
4315                 block_rsv->full = 1;
4316         }
4317
4318         spin_unlock(&block_rsv->lock);
4319         spin_unlock(&sinfo->lock);
4320 }
4321
4322 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4323 {
4324         struct btrfs_space_info *space_info;
4325
4326         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4327         fs_info->chunk_block_rsv.space_info = space_info;
4328
4329         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4330         fs_info->global_block_rsv.space_info = space_info;
4331         fs_info->delalloc_block_rsv.space_info = space_info;
4332         fs_info->trans_block_rsv.space_info = space_info;
4333         fs_info->empty_block_rsv.space_info = space_info;
4334         fs_info->delayed_block_rsv.space_info = space_info;
4335
4336         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4337         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4338         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4339         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4340         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4341
4342         update_global_block_rsv(fs_info);
4343 }
4344
4345 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4346 {
4347         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4348                                 (u64)-1);
4349         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4350         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4351         WARN_ON(fs_info->trans_block_rsv.size > 0);
4352         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4353         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4354         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4355         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4356         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4357 }
4358
4359 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4360                                   struct btrfs_root *root)
4361 {
4362         if (!trans->block_rsv)
4363                 return;
4364
4365         if (!trans->bytes_reserved)
4366                 return;
4367
4368         trace_btrfs_space_reservation(root->fs_info, "transaction",
4369                                       trans->transid, trans->bytes_reserved, 0);
4370         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4371         trans->bytes_reserved = 0;
4372 }
4373
4374 /* Can only return 0 or -ENOSPC */
4375 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4376                                   struct inode *inode)
4377 {
4378         struct btrfs_root *root = BTRFS_I(inode)->root;
4379         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4380         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4381
4382         /*
4383          * We need to hold space in order to delete our orphan item once we've
4384          * added it, so this takes the reservation so we can release it later
4385          * when we are truly done with the orphan item.
4386          */
4387         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4388         trace_btrfs_space_reservation(root->fs_info, "orphan",
4389                                       btrfs_ino(inode), num_bytes, 1);
4390         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4391 }
4392
4393 void btrfs_orphan_release_metadata(struct inode *inode)
4394 {
4395         struct btrfs_root *root = BTRFS_I(inode)->root;
4396         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4397         trace_btrfs_space_reservation(root->fs_info, "orphan",
4398                                       btrfs_ino(inode), num_bytes, 0);
4399         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4400 }
4401
4402 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4403                                 struct btrfs_pending_snapshot *pending)
4404 {
4405         struct btrfs_root *root = pending->root;
4406         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4407         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4408         /*
4409          * two for root back/forward refs, two for directory entries
4410          * and one for root of the snapshot.
4411          */
4412         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4413         dst_rsv->space_info = src_rsv->space_info;
4414         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4415 }
4416
4417 /**
4418  * drop_outstanding_extent - drop an outstanding extent
4419  * @inode: the inode we're dropping the extent for
4420  *
4421  * This is called when we are freeing up an outstanding extent, either called
4422  * after an error or after an extent is written.  This will return the number of
4423  * reserved extents that need to be freed.  This must be called with
4424  * BTRFS_I(inode)->lock held.
4425  */
4426 static unsigned drop_outstanding_extent(struct inode *inode)
4427 {
4428         unsigned drop_inode_space = 0;
4429         unsigned dropped_extents = 0;
4430
4431         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4432         BTRFS_I(inode)->outstanding_extents--;
4433
4434         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4435             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4436                                &BTRFS_I(inode)->runtime_flags))
4437                 drop_inode_space = 1;
4438
4439         /*
4440          * If we have more or the same amount of outsanding extents than we have
4441          * reserved then we need to leave the reserved extents count alone.
4442          */
4443         if (BTRFS_I(inode)->outstanding_extents >=
4444             BTRFS_I(inode)->reserved_extents)
4445                 return drop_inode_space;
4446
4447         dropped_extents = BTRFS_I(inode)->reserved_extents -
4448                 BTRFS_I(inode)->outstanding_extents;
4449         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4450         return dropped_extents + drop_inode_space;
4451 }
4452
4453 /**
4454  * calc_csum_metadata_size - return the amount of metada space that must be
4455  *      reserved/free'd for the given bytes.
4456  * @inode: the inode we're manipulating
4457  * @num_bytes: the number of bytes in question
4458  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4459  *
4460  * This adjusts the number of csum_bytes in the inode and then returns the
4461  * correct amount of metadata that must either be reserved or freed.  We
4462  * calculate how many checksums we can fit into one leaf and then divide the
4463  * number of bytes that will need to be checksumed by this value to figure out
4464  * how many checksums will be required.  If we are adding bytes then the number
4465  * may go up and we will return the number of additional bytes that must be
4466  * reserved.  If it is going down we will return the number of bytes that must
4467  * be freed.
4468  *
4469  * This must be called with BTRFS_I(inode)->lock held.
4470  */
4471 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4472                                    int reserve)
4473 {
4474         struct btrfs_root *root = BTRFS_I(inode)->root;
4475         u64 csum_size;
4476         int num_csums_per_leaf;
4477         int num_csums;
4478         int old_csums;
4479
4480         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4481             BTRFS_I(inode)->csum_bytes == 0)
4482                 return 0;
4483
4484         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4485         if (reserve)
4486                 BTRFS_I(inode)->csum_bytes += num_bytes;
4487         else
4488                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4489         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4490         num_csums_per_leaf = (int)div64_u64(csum_size,
4491                                             sizeof(struct btrfs_csum_item) +
4492                                             sizeof(struct btrfs_disk_key));
4493         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4494         num_csums = num_csums + num_csums_per_leaf - 1;
4495         num_csums = num_csums / num_csums_per_leaf;
4496
4497         old_csums = old_csums + num_csums_per_leaf - 1;
4498         old_csums = old_csums / num_csums_per_leaf;
4499
4500         /* No change, no need to reserve more */
4501         if (old_csums == num_csums)
4502                 return 0;
4503
4504         if (reserve)
4505                 return btrfs_calc_trans_metadata_size(root,
4506                                                       num_csums - old_csums);
4507
4508         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4509 }
4510
4511 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4512 {
4513         struct btrfs_root *root = BTRFS_I(inode)->root;
4514         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4515         u64 to_reserve = 0;
4516         u64 csum_bytes;
4517         unsigned nr_extents = 0;
4518         int extra_reserve = 0;
4519         int flush = 1;
4520         int ret;
4521
4522         /* Need to be holding the i_mutex here if we aren't free space cache */
4523         if (btrfs_is_free_space_inode(inode))
4524                 flush = 0;
4525
4526         if (flush && btrfs_transaction_in_commit(root->fs_info))
4527                 schedule_timeout(1);
4528
4529         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4530         num_bytes = ALIGN(num_bytes, root->sectorsize);
4531
4532         spin_lock(&BTRFS_I(inode)->lock);
4533         BTRFS_I(inode)->outstanding_extents++;
4534
4535         if (BTRFS_I(inode)->outstanding_extents >
4536             BTRFS_I(inode)->reserved_extents)
4537                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4538                         BTRFS_I(inode)->reserved_extents;
4539
4540         /*
4541          * Add an item to reserve for updating the inode when we complete the
4542          * delalloc io.
4543          */
4544         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4545                       &BTRFS_I(inode)->runtime_flags)) {
4546                 nr_extents++;
4547                 extra_reserve = 1;
4548         }
4549
4550         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4551         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4552         csum_bytes = BTRFS_I(inode)->csum_bytes;
4553         spin_unlock(&BTRFS_I(inode)->lock);
4554
4555         if (root->fs_info->quota_enabled) {
4556                 ret = btrfs_qgroup_reserve(root, num_bytes +
4557                                            nr_extents * root->leafsize);
4558                 if (ret) {
4559                         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4560                         return ret;
4561                 }
4562         }
4563
4564         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4565         if (ret) {
4566                 u64 to_free = 0;
4567                 unsigned dropped;
4568
4569                 spin_lock(&BTRFS_I(inode)->lock);
4570                 dropped = drop_outstanding_extent(inode);
4571                 /*
4572                  * If the inodes csum_bytes is the same as the original
4573                  * csum_bytes then we know we haven't raced with any free()ers
4574                  * so we can just reduce our inodes csum bytes and carry on.
4575                  * Otherwise we have to do the normal free thing to account for
4576                  * the case that the free side didn't free up its reserve
4577                  * because of this outstanding reservation.
4578                  */
4579                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4580                         calc_csum_metadata_size(inode, num_bytes, 0);
4581                 else
4582                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4583                 spin_unlock(&BTRFS_I(inode)->lock);
4584                 if (dropped)
4585                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4586
4587                 if (to_free) {
4588                         btrfs_block_rsv_release(root, block_rsv, to_free);
4589                         trace_btrfs_space_reservation(root->fs_info,
4590                                                       "delalloc",
4591                                                       btrfs_ino(inode),
4592                                                       to_free, 0);
4593                 }
4594                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4595                 return ret;
4596         }
4597
4598         spin_lock(&BTRFS_I(inode)->lock);
4599         if (extra_reserve) {
4600                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4601                         &BTRFS_I(inode)->runtime_flags);
4602                 nr_extents--;
4603         }
4604         BTRFS_I(inode)->reserved_extents += nr_extents;
4605         spin_unlock(&BTRFS_I(inode)->lock);
4606         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4607
4608         if (to_reserve)
4609                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4610                                               btrfs_ino(inode), to_reserve, 1);
4611         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4612
4613         return 0;
4614 }
4615
4616 /**
4617  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4618  * @inode: the inode to release the reservation for
4619  * @num_bytes: the number of bytes we're releasing
4620  *
4621  * This will release the metadata reservation for an inode.  This can be called
4622  * once we complete IO for a given set of bytes to release their metadata
4623  * reservations.
4624  */
4625 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4626 {
4627         struct btrfs_root *root = BTRFS_I(inode)->root;
4628         u64 to_free = 0;
4629         unsigned dropped;
4630
4631         num_bytes = ALIGN(num_bytes, root->sectorsize);
4632         spin_lock(&BTRFS_I(inode)->lock);
4633         dropped = drop_outstanding_extent(inode);
4634
4635         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4636         spin_unlock(&BTRFS_I(inode)->lock);
4637         if (dropped > 0)
4638                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4639
4640         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4641                                       btrfs_ino(inode), to_free, 0);
4642         if (root->fs_info->quota_enabled) {
4643                 btrfs_qgroup_free(root, num_bytes +
4644                                         dropped * root->leafsize);
4645         }
4646
4647         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4648                                 to_free);
4649 }
4650
4651 /**
4652  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4653  * @inode: inode we're writing to
4654  * @num_bytes: the number of bytes we want to allocate
4655  *
4656  * This will do the following things
4657  *
4658  * o reserve space in the data space info for num_bytes
4659  * o reserve space in the metadata space info based on number of outstanding
4660  *   extents and how much csums will be needed
4661  * o add to the inodes ->delalloc_bytes
4662  * o add it to the fs_info's delalloc inodes list.
4663  *
4664  * This will return 0 for success and -ENOSPC if there is no space left.
4665  */
4666 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4667 {
4668         int ret;
4669
4670         ret = btrfs_check_data_free_space(inode, num_bytes);
4671         if (ret)
4672                 return ret;
4673
4674         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4675         if (ret) {
4676                 btrfs_free_reserved_data_space(inode, num_bytes);
4677                 return ret;
4678         }
4679
4680         return 0;
4681 }
4682
4683 /**
4684  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4685  * @inode: inode we're releasing space for
4686  * @num_bytes: the number of bytes we want to free up
4687  *
4688  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4689  * called in the case that we don't need the metadata AND data reservations
4690  * anymore.  So if there is an error or we insert an inline extent.
4691  *
4692  * This function will release the metadata space that was not used and will
4693  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4694  * list if there are no delalloc bytes left.
4695  */
4696 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4697 {
4698         btrfs_delalloc_release_metadata(inode, num_bytes);
4699         btrfs_free_reserved_data_space(inode, num_bytes);
4700 }
4701
4702 static int update_block_group(struct btrfs_trans_handle *trans,
4703                               struct btrfs_root *root,
4704                               u64 bytenr, u64 num_bytes, int alloc)
4705 {
4706         struct btrfs_block_group_cache *cache = NULL;
4707         struct btrfs_fs_info *info = root->fs_info;
4708         u64 total = num_bytes;
4709         u64 old_val;
4710         u64 byte_in_group;
4711         int factor;
4712
4713         /* block accounting for super block */
4714         spin_lock(&info->delalloc_lock);
4715         old_val = btrfs_super_bytes_used(info->super_copy);
4716         if (alloc)
4717                 old_val += num_bytes;
4718         else
4719                 old_val -= num_bytes;
4720         btrfs_set_super_bytes_used(info->super_copy, old_val);
4721         spin_unlock(&info->delalloc_lock);
4722
4723         while (total) {
4724                 cache = btrfs_lookup_block_group(info, bytenr);
4725                 if (!cache)
4726                         return -ENOENT;
4727                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4728                                     BTRFS_BLOCK_GROUP_RAID1 |
4729                                     BTRFS_BLOCK_GROUP_RAID10))
4730                         factor = 2;
4731                 else
4732                         factor = 1;
4733                 /*
4734                  * If this block group has free space cache written out, we
4735                  * need to make sure to load it if we are removing space.  This
4736                  * is because we need the unpinning stage to actually add the
4737                  * space back to the block group, otherwise we will leak space.
4738                  */
4739                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4740                         cache_block_group(cache, trans, NULL, 1);
4741
4742                 byte_in_group = bytenr - cache->key.objectid;
4743                 WARN_ON(byte_in_group > cache->key.offset);
4744
4745                 spin_lock(&cache->space_info->lock);
4746                 spin_lock(&cache->lock);
4747
4748                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4749                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4750                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4751
4752                 cache->dirty = 1;
4753                 old_val = btrfs_block_group_used(&cache->item);
4754                 num_bytes = min(total, cache->key.offset - byte_in_group);
4755                 if (alloc) {
4756                         old_val += num_bytes;
4757                         btrfs_set_block_group_used(&cache->item, old_val);
4758                         cache->reserved -= num_bytes;
4759                         cache->space_info->bytes_reserved -= num_bytes;
4760                         cache->space_info->bytes_used += num_bytes;
4761                         cache->space_info->disk_used += num_bytes * factor;
4762                         spin_unlock(&cache->lock);
4763                         spin_unlock(&cache->space_info->lock);
4764                 } else {
4765                         old_val -= num_bytes;
4766                         btrfs_set_block_group_used(&cache->item, old_val);
4767                         cache->pinned += num_bytes;
4768                         cache->space_info->bytes_pinned += num_bytes;
4769                         cache->space_info->bytes_used -= num_bytes;
4770                         cache->space_info->disk_used -= num_bytes * factor;
4771                         spin_unlock(&cache->lock);
4772                         spin_unlock(&cache->space_info->lock);
4773
4774                         set_extent_dirty(info->pinned_extents,
4775                                          bytenr, bytenr + num_bytes - 1,
4776                                          GFP_NOFS | __GFP_NOFAIL);
4777                 }
4778                 btrfs_put_block_group(cache);
4779                 total -= num_bytes;
4780                 bytenr += num_bytes;
4781         }
4782         return 0;
4783 }
4784
4785 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4786 {
4787         struct btrfs_block_group_cache *cache;
4788         u64 bytenr;
4789
4790         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4791         if (!cache)
4792                 return 0;
4793
4794         bytenr = cache->key.objectid;
4795         btrfs_put_block_group(cache);
4796
4797         return bytenr;
4798 }
4799
4800 static int pin_down_extent(struct btrfs_root *root,
4801                            struct btrfs_block_group_cache *cache,
4802                            u64 bytenr, u64 num_bytes, int reserved)
4803 {
4804         spin_lock(&cache->space_info->lock);
4805         spin_lock(&cache->lock);
4806         cache->pinned += num_bytes;
4807         cache->space_info->bytes_pinned += num_bytes;
4808         if (reserved) {
4809                 cache->reserved -= num_bytes;
4810                 cache->space_info->bytes_reserved -= num_bytes;
4811         }
4812         spin_unlock(&cache->lock);
4813         spin_unlock(&cache->space_info->lock);
4814
4815         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4816                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4817         return 0;
4818 }
4819
4820 /*
4821  * this function must be called within transaction
4822  */
4823 int btrfs_pin_extent(struct btrfs_root *root,
4824                      u64 bytenr, u64 num_bytes, int reserved)
4825 {
4826         struct btrfs_block_group_cache *cache;
4827
4828         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4829         BUG_ON(!cache); /* Logic error */
4830
4831         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4832
4833         btrfs_put_block_group(cache);
4834         return 0;
4835 }
4836
4837 /*
4838  * this function must be called within transaction
4839  */
4840 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4841                                     struct btrfs_root *root,
4842                                     u64 bytenr, u64 num_bytes)
4843 {
4844         struct btrfs_block_group_cache *cache;
4845
4846         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4847         BUG_ON(!cache); /* Logic error */
4848
4849         /*
4850          * pull in the free space cache (if any) so that our pin
4851          * removes the free space from the cache.  We have load_only set
4852          * to one because the slow code to read in the free extents does check
4853          * the pinned extents.
4854          */
4855         cache_block_group(cache, trans, root, 1);
4856
4857         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4858
4859         /* remove us from the free space cache (if we're there at all) */
4860         btrfs_remove_free_space(cache, bytenr, num_bytes);
4861         btrfs_put_block_group(cache);
4862         return 0;
4863 }
4864
4865 /**
4866  * btrfs_update_reserved_bytes - update the block_group and space info counters
4867  * @cache:      The cache we are manipulating
4868  * @num_bytes:  The number of bytes in question
4869  * @reserve:    One of the reservation enums
4870  *
4871  * This is called by the allocator when it reserves space, or by somebody who is
4872  * freeing space that was never actually used on disk.  For example if you
4873  * reserve some space for a new leaf in transaction A and before transaction A
4874  * commits you free that leaf, you call this with reserve set to 0 in order to
4875  * clear the reservation.
4876  *
4877  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4878  * ENOSPC accounting.  For data we handle the reservation through clearing the
4879  * delalloc bits in the io_tree.  We have to do this since we could end up
4880  * allocating less disk space for the amount of data we have reserved in the
4881  * case of compression.
4882  *
4883  * If this is a reservation and the block group has become read only we cannot
4884  * make the reservation and return -EAGAIN, otherwise this function always
4885  * succeeds.
4886  */
4887 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4888                                        u64 num_bytes, int reserve)
4889 {
4890         struct btrfs_space_info *space_info = cache->space_info;
4891         int ret = 0;
4892
4893         spin_lock(&space_info->lock);
4894         spin_lock(&cache->lock);
4895         if (reserve != RESERVE_FREE) {
4896                 if (cache->ro) {
4897                         ret = -EAGAIN;
4898                 } else {
4899                         cache->reserved += num_bytes;
4900                         space_info->bytes_reserved += num_bytes;
4901                         if (reserve == RESERVE_ALLOC) {
4902                                 trace_btrfs_space_reservation(cache->fs_info,
4903                                                 "space_info", space_info->flags,
4904                                                 num_bytes, 0);
4905                                 space_info->bytes_may_use -= num_bytes;
4906                         }
4907                 }
4908         } else {
4909                 if (cache->ro)
4910                         space_info->bytes_readonly += num_bytes;
4911                 cache->reserved -= num_bytes;
4912                 space_info->bytes_reserved -= num_bytes;
4913                 space_info->reservation_progress++;
4914         }
4915         spin_unlock(&cache->lock);
4916         spin_unlock(&space_info->lock);
4917         return ret;
4918 }
4919
4920 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4921                                 struct btrfs_root *root)
4922 {
4923         struct btrfs_fs_info *fs_info = root->fs_info;
4924         struct btrfs_caching_control *next;
4925         struct btrfs_caching_control *caching_ctl;
4926         struct btrfs_block_group_cache *cache;
4927
4928         down_write(&fs_info->extent_commit_sem);
4929
4930         list_for_each_entry_safe(caching_ctl, next,
4931                                  &fs_info->caching_block_groups, list) {
4932                 cache = caching_ctl->block_group;
4933                 if (block_group_cache_done(cache)) {
4934                         cache->last_byte_to_unpin = (u64)-1;
4935                         list_del_init(&caching_ctl->list);
4936                         put_caching_control(caching_ctl);
4937                 } else {
4938                         cache->last_byte_to_unpin = caching_ctl->progress;
4939                 }
4940         }
4941
4942         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4943                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4944         else
4945                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4946
4947         up_write(&fs_info->extent_commit_sem);
4948
4949         update_global_block_rsv(fs_info);
4950 }
4951
4952 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4953 {
4954         struct btrfs_fs_info *fs_info = root->fs_info;
4955         struct btrfs_block_group_cache *cache = NULL;
4956         u64 len;
4957
4958         while (start <= end) {
4959                 if (!cache ||
4960                     start >= cache->key.objectid + cache->key.offset) {
4961                         if (cache)
4962                                 btrfs_put_block_group(cache);
4963                         cache = btrfs_lookup_block_group(fs_info, start);
4964                         BUG_ON(!cache); /* Logic error */
4965                 }
4966
4967                 len = cache->key.objectid + cache->key.offset - start;
4968                 len = min(len, end + 1 - start);
4969
4970                 if (start < cache->last_byte_to_unpin) {
4971                         len = min(len, cache->last_byte_to_unpin - start);
4972                         btrfs_add_free_space(cache, start, len);
4973                 }
4974
4975                 start += len;
4976
4977                 spin_lock(&cache->space_info->lock);
4978                 spin_lock(&cache->lock);
4979                 cache->pinned -= len;
4980                 cache->space_info->bytes_pinned -= len;
4981                 if (cache->ro)
4982                         cache->space_info->bytes_readonly += len;
4983                 spin_unlock(&cache->lock);
4984                 spin_unlock(&cache->space_info->lock);
4985         }
4986
4987         if (cache)
4988                 btrfs_put_block_group(cache);
4989         return 0;
4990 }
4991
4992 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4993                                struct btrfs_root *root)
4994 {
4995         struct btrfs_fs_info *fs_info = root->fs_info;
4996         struct extent_io_tree *unpin;
4997         u64 start;
4998         u64 end;
4999         int ret;
5000
5001         if (trans->aborted)
5002                 return 0;
5003
5004         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5005                 unpin = &fs_info->freed_extents[1];
5006         else
5007                 unpin = &fs_info->freed_extents[0];
5008
5009         while (1) {
5010                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5011                                             EXTENT_DIRTY);
5012                 if (ret)
5013                         break;
5014
5015                 if (btrfs_test_opt(root, DISCARD))
5016                         ret = btrfs_discard_extent(root, start,
5017                                                    end + 1 - start, NULL);
5018
5019                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5020                 unpin_extent_range(root, start, end);
5021                 cond_resched();
5022         }
5023
5024         return 0;
5025 }
5026
5027 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5028                                 struct btrfs_root *root,
5029                                 u64 bytenr, u64 num_bytes, u64 parent,
5030                                 u64 root_objectid, u64 owner_objectid,
5031                                 u64 owner_offset, int refs_to_drop,
5032                                 struct btrfs_delayed_extent_op *extent_op)
5033 {
5034         struct btrfs_key key;
5035         struct btrfs_path *path;
5036         struct btrfs_fs_info *info = root->fs_info;
5037         struct btrfs_root *extent_root = info->extent_root;
5038         struct extent_buffer *leaf;
5039         struct btrfs_extent_item *ei;
5040         struct btrfs_extent_inline_ref *iref;
5041         int ret;
5042         int is_data;
5043         int extent_slot = 0;
5044         int found_extent = 0;
5045         int num_to_del = 1;
5046         u32 item_size;
5047         u64 refs;
5048
5049         path = btrfs_alloc_path();
5050         if (!path)
5051                 return -ENOMEM;
5052
5053         path->reada = 1;
5054         path->leave_spinning = 1;
5055
5056         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5057         BUG_ON(!is_data && refs_to_drop != 1);
5058
5059         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5060                                     bytenr, num_bytes, parent,
5061                                     root_objectid, owner_objectid,
5062                                     owner_offset);
5063         if (ret == 0) {
5064                 extent_slot = path->slots[0];
5065                 while (extent_slot >= 0) {
5066                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5067                                               extent_slot);
5068                         if (key.objectid != bytenr)
5069                                 break;
5070                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5071                             key.offset == num_bytes) {
5072                                 found_extent = 1;
5073                                 break;
5074                         }
5075                         if (path->slots[0] - extent_slot > 5)
5076                                 break;
5077                         extent_slot--;
5078                 }
5079 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5080                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5081                 if (found_extent && item_size < sizeof(*ei))
5082                         found_extent = 0;
5083 #endif
5084                 if (!found_extent) {
5085                         BUG_ON(iref);
5086                         ret = remove_extent_backref(trans, extent_root, path,
5087                                                     NULL, refs_to_drop,
5088                                                     is_data);
5089                         if (ret)
5090                                 goto abort;
5091                         btrfs_release_path(path);
5092                         path->leave_spinning = 1;
5093
5094                         key.objectid = bytenr;
5095                         key.type = BTRFS_EXTENT_ITEM_KEY;
5096                         key.offset = num_bytes;
5097
5098                         ret = btrfs_search_slot(trans, extent_root,
5099                                                 &key, path, -1, 1);
5100                         if (ret) {
5101                                 printk(KERN_ERR "umm, got %d back from search"
5102                                        ", was looking for %llu\n", ret,
5103                                        (unsigned long long)bytenr);
5104                                 if (ret > 0)
5105                                         btrfs_print_leaf(extent_root,
5106                                                          path->nodes[0]);
5107                         }
5108                         if (ret < 0)
5109                                 goto abort;
5110                         extent_slot = path->slots[0];
5111                 }
5112         } else if (ret == -ENOENT) {
5113                 btrfs_print_leaf(extent_root, path->nodes[0]);
5114                 WARN_ON(1);
5115                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
5116                        "parent %llu root %llu  owner %llu offset %llu\n",
5117                        (unsigned long long)bytenr,
5118                        (unsigned long long)parent,
5119                        (unsigned long long)root_objectid,
5120                        (unsigned long long)owner_objectid,
5121                        (unsigned long long)owner_offset);
5122         } else {
5123                 goto abort;
5124         }
5125
5126         leaf = path->nodes[0];
5127         item_size = btrfs_item_size_nr(leaf, extent_slot);
5128 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5129         if (item_size < sizeof(*ei)) {
5130                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5131                 ret = convert_extent_item_v0(trans, extent_root, path,
5132                                              owner_objectid, 0);
5133                 if (ret < 0)
5134                         goto abort;
5135
5136                 btrfs_release_path(path);
5137                 path->leave_spinning = 1;
5138
5139                 key.objectid = bytenr;
5140                 key.type = BTRFS_EXTENT_ITEM_KEY;
5141                 key.offset = num_bytes;
5142
5143                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5144                                         -1, 1);
5145                 if (ret) {
5146                         printk(KERN_ERR "umm, got %d back from search"
5147                                ", was looking for %llu\n", ret,
5148                                (unsigned long long)bytenr);
5149                         btrfs_print_leaf(extent_root, path->nodes[0]);
5150                 }
5151                 if (ret < 0)
5152                         goto abort;
5153                 extent_slot = path->slots[0];
5154                 leaf = path->nodes[0];
5155                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5156         }
5157 #endif
5158         BUG_ON(item_size < sizeof(*ei));
5159         ei = btrfs_item_ptr(leaf, extent_slot,
5160                             struct btrfs_extent_item);
5161         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5162                 struct btrfs_tree_block_info *bi;
5163                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5164                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5165                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5166         }
5167
5168         refs = btrfs_extent_refs(leaf, ei);
5169         BUG_ON(refs < refs_to_drop);
5170         refs -= refs_to_drop;
5171
5172         if (refs > 0) {
5173                 if (extent_op)
5174                         __run_delayed_extent_op(extent_op, leaf, ei);
5175                 /*
5176                  * In the case of inline back ref, reference count will
5177                  * be updated by remove_extent_backref
5178                  */
5179                 if (iref) {
5180                         BUG_ON(!found_extent);
5181                 } else {
5182                         btrfs_set_extent_refs(leaf, ei, refs);
5183                         btrfs_mark_buffer_dirty(leaf);
5184                 }
5185                 if (found_extent) {
5186                         ret = remove_extent_backref(trans, extent_root, path,
5187                                                     iref, refs_to_drop,
5188                                                     is_data);
5189                         if (ret)
5190                                 goto abort;
5191                 }
5192         } else {
5193                 if (found_extent) {
5194                         BUG_ON(is_data && refs_to_drop !=
5195                                extent_data_ref_count(root, path, iref));
5196                         if (iref) {
5197                                 BUG_ON(path->slots[0] != extent_slot);
5198                         } else {
5199                                 BUG_ON(path->slots[0] != extent_slot + 1);
5200                                 path->slots[0] = extent_slot;
5201                                 num_to_del = 2;
5202                         }
5203                 }
5204
5205                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5206                                       num_to_del);
5207                 if (ret)
5208                         goto abort;
5209                 btrfs_release_path(path);
5210
5211                 if (is_data) {
5212                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5213                         if (ret)
5214                                 goto abort;
5215                 }
5216
5217                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5218                 if (ret)
5219                         goto abort;
5220         }
5221 out:
5222         btrfs_free_path(path);
5223         return ret;
5224
5225 abort:
5226         btrfs_abort_transaction(trans, extent_root, ret);
5227         goto out;
5228 }
5229
5230 /*
5231  * when we free an block, it is possible (and likely) that we free the last
5232  * delayed ref for that extent as well.  This searches the delayed ref tree for
5233  * a given extent, and if there are no other delayed refs to be processed, it
5234  * removes it from the tree.
5235  */
5236 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5237                                       struct btrfs_root *root, u64 bytenr)
5238 {
5239         struct btrfs_delayed_ref_head *head;
5240         struct btrfs_delayed_ref_root *delayed_refs;
5241         struct btrfs_delayed_ref_node *ref;
5242         struct rb_node *node;
5243         int ret = 0;
5244
5245         delayed_refs = &trans->transaction->delayed_refs;
5246         spin_lock(&delayed_refs->lock);
5247         head = btrfs_find_delayed_ref_head(trans, bytenr);
5248         if (!head)
5249                 goto out;
5250
5251         node = rb_prev(&head->node.rb_node);
5252         if (!node)
5253                 goto out;
5254
5255         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5256
5257         /* there are still entries for this ref, we can't drop it */
5258         if (ref->bytenr == bytenr)
5259                 goto out;
5260
5261         if (head->extent_op) {
5262                 if (!head->must_insert_reserved)
5263                         goto out;
5264                 kfree(head->extent_op);
5265                 head->extent_op = NULL;
5266         }
5267
5268         /*
5269          * waiting for the lock here would deadlock.  If someone else has it
5270          * locked they are already in the process of dropping it anyway
5271          */
5272         if (!mutex_trylock(&head->mutex))
5273                 goto out;
5274
5275         /*
5276          * at this point we have a head with no other entries.  Go
5277          * ahead and process it.
5278          */
5279         head->node.in_tree = 0;
5280         rb_erase(&head->node.rb_node, &delayed_refs->root);
5281
5282         delayed_refs->num_entries--;
5283
5284         /*
5285          * we don't take a ref on the node because we're removing it from the
5286          * tree, so we just steal the ref the tree was holding.
5287          */
5288         delayed_refs->num_heads--;
5289         if (list_empty(&head->cluster))
5290                 delayed_refs->num_heads_ready--;
5291
5292         list_del_init(&head->cluster);
5293         spin_unlock(&delayed_refs->lock);
5294
5295         BUG_ON(head->extent_op);
5296         if (head->must_insert_reserved)
5297                 ret = 1;
5298
5299         mutex_unlock(&head->mutex);
5300         btrfs_put_delayed_ref(&head->node);
5301         return ret;
5302 out:
5303         spin_unlock(&delayed_refs->lock);
5304         return 0;
5305 }
5306
5307 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5308                            struct btrfs_root *root,
5309                            struct extent_buffer *buf,
5310                            u64 parent, int last_ref)
5311 {
5312         struct btrfs_block_group_cache *cache = NULL;
5313         int ret;
5314
5315         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5316                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5317                                         buf->start, buf->len,
5318                                         parent, root->root_key.objectid,
5319                                         btrfs_header_level(buf),
5320                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5321                 BUG_ON(ret); /* -ENOMEM */
5322         }
5323
5324         if (!last_ref)
5325                 return;
5326
5327         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5328
5329         if (btrfs_header_generation(buf) == trans->transid) {
5330                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5331                         ret = check_ref_cleanup(trans, root, buf->start);
5332                         if (!ret)
5333                                 goto out;
5334                 }
5335
5336                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5337                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5338                         goto out;
5339                 }
5340
5341                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5342
5343                 btrfs_add_free_space(cache, buf->start, buf->len);
5344                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5345         }
5346 out:
5347         /*
5348          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5349          * anymore.
5350          */
5351         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5352         btrfs_put_block_group(cache);
5353 }
5354
5355 /* Can return -ENOMEM */
5356 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5357                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5358                       u64 owner, u64 offset, int for_cow)
5359 {
5360         int ret;
5361         struct btrfs_fs_info *fs_info = root->fs_info;
5362
5363         /*
5364          * tree log blocks never actually go into the extent allocation
5365          * tree, just update pinning info and exit early.
5366          */
5367         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5368                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5369                 /* unlocks the pinned mutex */
5370                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5371                 ret = 0;
5372         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5373                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5374                                         num_bytes,
5375                                         parent, root_objectid, (int)owner,
5376                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5377         } else {
5378                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5379                                                 num_bytes,
5380                                                 parent, root_objectid, owner,
5381                                                 offset, BTRFS_DROP_DELAYED_REF,
5382                                                 NULL, for_cow);
5383         }
5384         return ret;
5385 }
5386
5387 static u64 stripe_align(struct btrfs_root *root, u64 val)
5388 {
5389         u64 mask = ((u64)root->stripesize - 1);
5390         u64 ret = (val + mask) & ~mask;
5391         return ret;
5392 }
5393
5394 /*
5395  * when we wait for progress in the block group caching, its because
5396  * our allocation attempt failed at least once.  So, we must sleep
5397  * and let some progress happen before we try again.
5398  *
5399  * This function will sleep at least once waiting for new free space to
5400  * show up, and then it will check the block group free space numbers
5401  * for our min num_bytes.  Another option is to have it go ahead
5402  * and look in the rbtree for a free extent of a given size, but this
5403  * is a good start.
5404  */
5405 static noinline int
5406 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5407                                 u64 num_bytes)
5408 {
5409         struct btrfs_caching_control *caching_ctl;
5410         DEFINE_WAIT(wait);
5411
5412         caching_ctl = get_caching_control(cache);
5413         if (!caching_ctl)
5414                 return 0;
5415
5416         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5417                    (cache->free_space_ctl->free_space >= num_bytes));
5418
5419         put_caching_control(caching_ctl);
5420         return 0;
5421 }
5422
5423 static noinline int
5424 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5425 {
5426         struct btrfs_caching_control *caching_ctl;
5427         DEFINE_WAIT(wait);
5428
5429         caching_ctl = get_caching_control(cache);
5430         if (!caching_ctl)
5431                 return 0;
5432
5433         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5434
5435         put_caching_control(caching_ctl);
5436         return 0;
5437 }
5438
5439 static int __get_block_group_index(u64 flags)
5440 {
5441         int index;
5442
5443         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5444                 index = 0;
5445         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5446                 index = 1;
5447         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5448                 index = 2;
5449         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5450                 index = 3;
5451         else
5452                 index = 4;
5453
5454         return index;
5455 }
5456
5457 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5458 {
5459         return __get_block_group_index(cache->flags);
5460 }
5461
5462 enum btrfs_loop_type {
5463         LOOP_CACHING_NOWAIT = 0,
5464         LOOP_CACHING_WAIT = 1,
5465         LOOP_ALLOC_CHUNK = 2,
5466         LOOP_NO_EMPTY_SIZE = 3,
5467 };
5468
5469 /*
5470  * walks the btree of allocated extents and find a hole of a given size.
5471  * The key ins is changed to record the hole:
5472  * ins->objectid == block start
5473  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5474  * ins->offset == number of blocks
5475  * Any available blocks before search_start are skipped.
5476  */
5477 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5478                                      struct btrfs_root *orig_root,
5479                                      u64 num_bytes, u64 empty_size,
5480                                      u64 hint_byte, struct btrfs_key *ins,
5481                                      u64 data)
5482 {
5483         int ret = 0;
5484         struct btrfs_root *root = orig_root->fs_info->extent_root;
5485         struct btrfs_free_cluster *last_ptr = NULL;
5486         struct btrfs_block_group_cache *block_group = NULL;
5487         struct btrfs_block_group_cache *used_block_group;
5488         u64 search_start = 0;
5489         int empty_cluster = 2 * 1024 * 1024;
5490         int allowed_chunk_alloc = 0;
5491         int done_chunk_alloc = 0;
5492         struct btrfs_space_info *space_info;
5493         int loop = 0;
5494         int index = 0;
5495         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5496                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5497         bool found_uncached_bg = false;
5498         bool failed_cluster_refill = false;
5499         bool failed_alloc = false;
5500         bool use_cluster = true;
5501         bool have_caching_bg = false;
5502
5503         WARN_ON(num_bytes < root->sectorsize);
5504         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5505         ins->objectid = 0;
5506         ins->offset = 0;
5507
5508         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5509
5510         space_info = __find_space_info(root->fs_info, data);
5511         if (!space_info) {
5512                 printk(KERN_ERR "No space info for %llu\n", data);
5513                 return -ENOSPC;
5514         }
5515
5516         /*
5517          * If the space info is for both data and metadata it means we have a
5518          * small filesystem and we can't use the clustering stuff.
5519          */
5520         if (btrfs_mixed_space_info(space_info))
5521                 use_cluster = false;
5522
5523         if (orig_root->ref_cows || empty_size)
5524                 allowed_chunk_alloc = 1;
5525
5526         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5527                 last_ptr = &root->fs_info->meta_alloc_cluster;
5528                 if (!btrfs_test_opt(root, SSD))
5529                         empty_cluster = 64 * 1024;
5530         }
5531
5532         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5533             btrfs_test_opt(root, SSD)) {
5534                 last_ptr = &root->fs_info->data_alloc_cluster;
5535         }
5536
5537         if (last_ptr) {
5538                 spin_lock(&last_ptr->lock);
5539                 if (last_ptr->block_group)
5540                         hint_byte = last_ptr->window_start;
5541                 spin_unlock(&last_ptr->lock);
5542         }
5543
5544         search_start = max(search_start, first_logical_byte(root, 0));
5545         search_start = max(search_start, hint_byte);
5546
5547         if (!last_ptr)
5548                 empty_cluster = 0;
5549
5550         if (search_start == hint_byte) {
5551                 block_group = btrfs_lookup_block_group(root->fs_info,
5552                                                        search_start);
5553                 used_block_group = block_group;
5554                 /*
5555                  * we don't want to use the block group if it doesn't match our
5556                  * allocation bits, or if its not cached.
5557                  *
5558                  * However if we are re-searching with an ideal block group
5559                  * picked out then we don't care that the block group is cached.
5560                  */
5561                 if (block_group && block_group_bits(block_group, data) &&
5562                     block_group->cached != BTRFS_CACHE_NO) {
5563                         down_read(&space_info->groups_sem);
5564                         if (list_empty(&block_group->list) ||
5565                             block_group->ro) {
5566                                 /*
5567                                  * someone is removing this block group,
5568                                  * we can't jump into the have_block_group
5569                                  * target because our list pointers are not
5570                                  * valid
5571                                  */
5572                                 btrfs_put_block_group(block_group);
5573                                 up_read(&space_info->groups_sem);
5574                         } else {
5575                                 index = get_block_group_index(block_group);
5576                                 goto have_block_group;
5577                         }
5578                 } else if (block_group) {
5579                         btrfs_put_block_group(block_group);
5580                 }
5581         }
5582 search:
5583         have_caching_bg = false;
5584         down_read(&space_info->groups_sem);
5585         list_for_each_entry(block_group, &space_info->block_groups[index],
5586                             list) {
5587                 u64 offset;
5588                 int cached;
5589
5590                 used_block_group = block_group;
5591                 btrfs_get_block_group(block_group);
5592                 search_start = block_group->key.objectid;
5593
5594                 /*
5595                  * this can happen if we end up cycling through all the
5596                  * raid types, but we want to make sure we only allocate
5597                  * for the proper type.
5598                  */
5599                 if (!block_group_bits(block_group, data)) {
5600                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5601                                 BTRFS_BLOCK_GROUP_RAID1 |
5602                                 BTRFS_BLOCK_GROUP_RAID10;
5603
5604                         /*
5605                          * if they asked for extra copies and this block group
5606                          * doesn't provide them, bail.  This does allow us to
5607                          * fill raid0 from raid1.
5608                          */
5609                         if ((data & extra) && !(block_group->flags & extra))
5610                                 goto loop;
5611                 }
5612
5613 have_block_group:
5614                 cached = block_group_cache_done(block_group);
5615                 if (unlikely(!cached)) {
5616                         found_uncached_bg = true;
5617                         ret = cache_block_group(block_group, trans,
5618                                                 orig_root, 0);
5619                         BUG_ON(ret < 0);
5620                         ret = 0;
5621                 }
5622
5623                 if (unlikely(block_group->ro))
5624                         goto loop;
5625
5626                 /*
5627                  * Ok we want to try and use the cluster allocator, so
5628                  * lets look there
5629                  */
5630                 if (last_ptr) {
5631                         /*
5632                          * the refill lock keeps out other
5633                          * people trying to start a new cluster
5634                          */
5635                         spin_lock(&last_ptr->refill_lock);
5636                         used_block_group = last_ptr->block_group;
5637                         if (used_block_group != block_group &&
5638                             (!used_block_group ||
5639                              used_block_group->ro ||
5640                              !block_group_bits(used_block_group, data))) {
5641                                 used_block_group = block_group;
5642                                 goto refill_cluster;
5643                         }
5644
5645                         if (used_block_group != block_group)
5646                                 btrfs_get_block_group(used_block_group);
5647
5648                         offset = btrfs_alloc_from_cluster(used_block_group,
5649                           last_ptr, num_bytes, used_block_group->key.objectid);
5650                         if (offset) {
5651                                 /* we have a block, we're done */
5652                                 spin_unlock(&last_ptr->refill_lock);
5653                                 trace_btrfs_reserve_extent_cluster(root,
5654                                         block_group, search_start, num_bytes);
5655                                 goto checks;
5656                         }
5657
5658                         WARN_ON(last_ptr->block_group != used_block_group);
5659                         if (used_block_group != block_group) {
5660                                 btrfs_put_block_group(used_block_group);
5661                                 used_block_group = block_group;
5662                         }
5663 refill_cluster:
5664                         BUG_ON(used_block_group != block_group);
5665                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5666                          * set up a new clusters, so lets just skip it
5667                          * and let the allocator find whatever block
5668                          * it can find.  If we reach this point, we
5669                          * will have tried the cluster allocator
5670                          * plenty of times and not have found
5671                          * anything, so we are likely way too
5672                          * fragmented for the clustering stuff to find
5673                          * anything.
5674                          *
5675                          * However, if the cluster is taken from the
5676                          * current block group, release the cluster
5677                          * first, so that we stand a better chance of
5678                          * succeeding in the unclustered
5679                          * allocation.  */
5680                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5681                             last_ptr->block_group != block_group) {
5682                                 spin_unlock(&last_ptr->refill_lock);
5683                                 goto unclustered_alloc;
5684                         }
5685
5686                         /*
5687                          * this cluster didn't work out, free it and
5688                          * start over
5689                          */
5690                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5691
5692                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5693                                 spin_unlock(&last_ptr->refill_lock);
5694                                 goto unclustered_alloc;
5695                         }
5696
5697                         /* allocate a cluster in this block group */
5698                         ret = btrfs_find_space_cluster(trans, root,
5699                                                block_group, last_ptr,
5700                                                search_start, num_bytes,
5701                                                empty_cluster + empty_size);
5702                         if (ret == 0) {
5703                                 /*
5704                                  * now pull our allocation out of this
5705                                  * cluster
5706                                  */
5707                                 offset = btrfs_alloc_from_cluster(block_group,
5708                                                   last_ptr, num_bytes,
5709                                                   search_start);
5710                                 if (offset) {
5711                                         /* we found one, proceed */
5712                                         spin_unlock(&last_ptr->refill_lock);
5713                                         trace_btrfs_reserve_extent_cluster(root,
5714                                                 block_group, search_start,
5715                                                 num_bytes);
5716                                         goto checks;
5717                                 }
5718                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5719                                    && !failed_cluster_refill) {
5720                                 spin_unlock(&last_ptr->refill_lock);
5721
5722                                 failed_cluster_refill = true;
5723                                 wait_block_group_cache_progress(block_group,
5724                                        num_bytes + empty_cluster + empty_size);
5725                                 goto have_block_group;
5726                         }
5727
5728                         /*
5729                          * at this point we either didn't find a cluster
5730                          * or we weren't able to allocate a block from our
5731                          * cluster.  Free the cluster we've been trying
5732                          * to use, and go to the next block group
5733                          */
5734                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5735                         spin_unlock(&last_ptr->refill_lock);
5736                         goto loop;
5737                 }
5738
5739 unclustered_alloc:
5740                 spin_lock(&block_group->free_space_ctl->tree_lock);
5741                 if (cached &&
5742                     block_group->free_space_ctl->free_space <
5743                     num_bytes + empty_cluster + empty_size) {
5744                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5745                         goto loop;
5746                 }
5747                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5748
5749                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5750                                                     num_bytes, empty_size);
5751                 /*
5752                  * If we didn't find a chunk, and we haven't failed on this
5753                  * block group before, and this block group is in the middle of
5754                  * caching and we are ok with waiting, then go ahead and wait
5755                  * for progress to be made, and set failed_alloc to true.
5756                  *
5757                  * If failed_alloc is true then we've already waited on this
5758                  * block group once and should move on to the next block group.
5759                  */
5760                 if (!offset && !failed_alloc && !cached &&
5761                     loop > LOOP_CACHING_NOWAIT) {
5762                         wait_block_group_cache_progress(block_group,
5763                                                 num_bytes + empty_size);
5764                         failed_alloc = true;
5765                         goto have_block_group;
5766                 } else if (!offset) {
5767                         if (!cached)
5768                                 have_caching_bg = true;
5769                         goto loop;
5770                 }
5771 checks:
5772                 search_start = stripe_align(root, offset);
5773
5774                 /* move on to the next group */
5775                 if (search_start + num_bytes >
5776                     used_block_group->key.objectid + used_block_group->key.offset) {
5777                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5778                         goto loop;
5779                 }
5780
5781                 if (offset < search_start)
5782                         btrfs_add_free_space(used_block_group, offset,
5783                                              search_start - offset);
5784                 BUG_ON(offset > search_start);
5785
5786                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5787                                                   alloc_type);
5788                 if (ret == -EAGAIN) {
5789                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5790                         goto loop;
5791                 }
5792
5793                 /* we are all good, lets return */
5794                 ins->objectid = search_start;
5795                 ins->offset = num_bytes;
5796
5797                 trace_btrfs_reserve_extent(orig_root, block_group,
5798                                            search_start, num_bytes);
5799                 if (offset < search_start)
5800                         btrfs_add_free_space(used_block_group, offset,
5801                                              search_start - offset);
5802                 BUG_ON(offset > search_start);
5803                 if (used_block_group != block_group)
5804                         btrfs_put_block_group(used_block_group);
5805                 btrfs_put_block_group(block_group);
5806                 break;
5807 loop:
5808                 failed_cluster_refill = false;
5809                 failed_alloc = false;
5810                 BUG_ON(index != get_block_group_index(block_group));
5811                 if (used_block_group != block_group)
5812                         btrfs_put_block_group(used_block_group);
5813                 btrfs_put_block_group(block_group);
5814         }
5815         up_read(&space_info->groups_sem);
5816
5817         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5818                 goto search;
5819
5820         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5821                 goto search;
5822
5823         /*
5824          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5825          *                      caching kthreads as we move along
5826          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5827          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5828          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5829          *                      again
5830          */
5831         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5832                 index = 0;
5833                 loop++;
5834                 if (loop == LOOP_ALLOC_CHUNK) {
5835                        if (allowed_chunk_alloc) {
5836                                 ret = do_chunk_alloc(trans, root, num_bytes +
5837                                                      2 * 1024 * 1024, data,
5838                                                      CHUNK_ALLOC_LIMITED);
5839                                 /*
5840                                  * Do not bail out on ENOSPC since we
5841                                  * can do more things.
5842                                  */
5843                                 if (ret < 0 && ret != -ENOSPC) {
5844                                         btrfs_abort_transaction(trans,
5845                                                                 root, ret);
5846                                         goto out;
5847                                 }
5848                                 allowed_chunk_alloc = 0;
5849                                 if (ret == 1)
5850                                         done_chunk_alloc = 1;
5851                         } else if (!done_chunk_alloc &&
5852                                    space_info->force_alloc ==
5853                                    CHUNK_ALLOC_NO_FORCE) {
5854                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5855                         }
5856
5857                        /*
5858                         * We didn't allocate a chunk, go ahead and drop the
5859                         * empty size and loop again.
5860                         */
5861                        if (!done_chunk_alloc)
5862                                loop = LOOP_NO_EMPTY_SIZE;
5863                 }
5864
5865                 if (loop == LOOP_NO_EMPTY_SIZE) {
5866                         empty_size = 0;
5867                         empty_cluster = 0;
5868                 }
5869
5870                 goto search;
5871         } else if (!ins->objectid) {
5872                 ret = -ENOSPC;
5873         } else if (ins->objectid) {
5874                 ret = 0;
5875         }
5876 out:
5877
5878         return ret;
5879 }
5880
5881 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5882                             int dump_block_groups)
5883 {
5884         struct btrfs_block_group_cache *cache;
5885         int index = 0;
5886
5887         spin_lock(&info->lock);
5888         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5889                (unsigned long long)info->flags,
5890                (unsigned long long)(info->total_bytes - info->bytes_used -
5891                                     info->bytes_pinned - info->bytes_reserved -
5892                                     info->bytes_readonly),
5893                (info->full) ? "" : "not ");
5894         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5895                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5896                (unsigned long long)info->total_bytes,
5897                (unsigned long long)info->bytes_used,
5898                (unsigned long long)info->bytes_pinned,
5899                (unsigned long long)info->bytes_reserved,
5900                (unsigned long long)info->bytes_may_use,
5901                (unsigned long long)info->bytes_readonly);
5902         spin_unlock(&info->lock);
5903
5904         if (!dump_block_groups)
5905                 return;
5906
5907         down_read(&info->groups_sem);
5908 again:
5909         list_for_each_entry(cache, &info->block_groups[index], list) {
5910                 spin_lock(&cache->lock);
5911                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
5912                        (unsigned long long)cache->key.objectid,
5913                        (unsigned long long)cache->key.offset,
5914                        (unsigned long long)btrfs_block_group_used(&cache->item),
5915                        (unsigned long long)cache->pinned,
5916                        (unsigned long long)cache->reserved,
5917                        cache->ro ? "[readonly]" : "");
5918                 btrfs_dump_free_space(cache, bytes);
5919                 spin_unlock(&cache->lock);
5920         }
5921         if (++index < BTRFS_NR_RAID_TYPES)
5922                 goto again;
5923         up_read(&info->groups_sem);
5924 }
5925
5926 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5927                          struct btrfs_root *root,
5928                          u64 num_bytes, u64 min_alloc_size,
5929                          u64 empty_size, u64 hint_byte,
5930                          struct btrfs_key *ins, u64 data)
5931 {
5932         bool final_tried = false;
5933         int ret;
5934
5935         data = btrfs_get_alloc_profile(root, data);
5936 again:
5937         /*
5938          * the only place that sets empty_size is btrfs_realloc_node, which
5939          * is not called recursively on allocations
5940          */
5941         if (empty_size || root->ref_cows) {
5942                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5943                                      num_bytes + 2 * 1024 * 1024, data,
5944                                      CHUNK_ALLOC_NO_FORCE);
5945                 if (ret < 0 && ret != -ENOSPC) {
5946                         btrfs_abort_transaction(trans, root, ret);
5947                         return ret;
5948                 }
5949         }
5950
5951         WARN_ON(num_bytes < root->sectorsize);
5952         ret = find_free_extent(trans, root, num_bytes, empty_size,
5953                                hint_byte, ins, data);
5954
5955         if (ret == -ENOSPC) {
5956                 if (!final_tried) {
5957                         num_bytes = num_bytes >> 1;
5958                         num_bytes = num_bytes & ~(root->sectorsize - 1);
5959                         num_bytes = max(num_bytes, min_alloc_size);
5960                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5961                                        num_bytes, data, CHUNK_ALLOC_FORCE);
5962                         if (ret < 0 && ret != -ENOSPC) {
5963                                 btrfs_abort_transaction(trans, root, ret);
5964                                 return ret;
5965                         }
5966                         if (num_bytes == min_alloc_size)
5967                                 final_tried = true;
5968                         goto again;
5969                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
5970                         struct btrfs_space_info *sinfo;
5971
5972                         sinfo = __find_space_info(root->fs_info, data);
5973                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
5974                                "wanted %llu\n", (unsigned long long)data,
5975                                (unsigned long long)num_bytes);
5976                         if (sinfo)
5977                                 dump_space_info(sinfo, num_bytes, 1);
5978                 }
5979         }
5980
5981         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5982
5983         return ret;
5984 }
5985
5986 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5987                                         u64 start, u64 len, int pin)
5988 {
5989         struct btrfs_block_group_cache *cache;
5990         int ret = 0;
5991
5992         cache = btrfs_lookup_block_group(root->fs_info, start);
5993         if (!cache) {
5994                 printk(KERN_ERR "Unable to find block group for %llu\n",
5995                        (unsigned long long)start);
5996                 return -ENOSPC;
5997         }
5998
5999         if (btrfs_test_opt(root, DISCARD))
6000                 ret = btrfs_discard_extent(root, start, len, NULL);
6001
6002         if (pin)
6003                 pin_down_extent(root, cache, start, len, 1);
6004         else {
6005                 btrfs_add_free_space(cache, start, len);
6006                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6007         }
6008         btrfs_put_block_group(cache);
6009
6010         trace_btrfs_reserved_extent_free(root, start, len);
6011
6012         return ret;
6013 }
6014
6015 int btrfs_free_reserved_extent(struct btrfs_root *root,
6016                                         u64 start, u64 len)
6017 {
6018         return __btrfs_free_reserved_extent(root, start, len, 0);
6019 }
6020
6021 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6022                                        u64 start, u64 len)
6023 {
6024         return __btrfs_free_reserved_extent(root, start, len, 1);
6025 }
6026
6027 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6028                                       struct btrfs_root *root,
6029                                       u64 parent, u64 root_objectid,
6030                                       u64 flags, u64 owner, u64 offset,
6031                                       struct btrfs_key *ins, int ref_mod)
6032 {
6033         int ret;
6034         struct btrfs_fs_info *fs_info = root->fs_info;
6035         struct btrfs_extent_item *extent_item;
6036         struct btrfs_extent_inline_ref *iref;
6037         struct btrfs_path *path;
6038         struct extent_buffer *leaf;
6039         int type;
6040         u32 size;
6041
6042         if (parent > 0)
6043                 type = BTRFS_SHARED_DATA_REF_KEY;
6044         else
6045                 type = BTRFS_EXTENT_DATA_REF_KEY;
6046
6047         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6048
6049         path = btrfs_alloc_path();
6050         if (!path)
6051                 return -ENOMEM;
6052
6053         path->leave_spinning = 1;
6054         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6055                                       ins, size);
6056         if (ret) {
6057                 btrfs_free_path(path);
6058                 return ret;
6059         }
6060
6061         leaf = path->nodes[0];
6062         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6063                                      struct btrfs_extent_item);
6064         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6065         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6066         btrfs_set_extent_flags(leaf, extent_item,
6067                                flags | BTRFS_EXTENT_FLAG_DATA);
6068
6069         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6070         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6071         if (parent > 0) {
6072                 struct btrfs_shared_data_ref *ref;
6073                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6074                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6075                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6076         } else {
6077                 struct btrfs_extent_data_ref *ref;
6078                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6079                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6080                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6081                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6082                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6083         }
6084
6085         btrfs_mark_buffer_dirty(path->nodes[0]);
6086         btrfs_free_path(path);
6087
6088         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6089         if (ret) { /* -ENOENT, logic error */
6090                 printk(KERN_ERR "btrfs update block group failed for %llu "
6091                        "%llu\n", (unsigned long long)ins->objectid,
6092                        (unsigned long long)ins->offset);
6093                 BUG();
6094         }
6095         return ret;
6096 }
6097
6098 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6099                                      struct btrfs_root *root,
6100                                      u64 parent, u64 root_objectid,
6101                                      u64 flags, struct btrfs_disk_key *key,
6102                                      int level, struct btrfs_key *ins)
6103 {
6104         int ret;
6105         struct btrfs_fs_info *fs_info = root->fs_info;
6106         struct btrfs_extent_item *extent_item;
6107         struct btrfs_tree_block_info *block_info;
6108         struct btrfs_extent_inline_ref *iref;
6109         struct btrfs_path *path;
6110         struct extent_buffer *leaf;
6111         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
6112
6113         path = btrfs_alloc_path();
6114         if (!path)
6115                 return -ENOMEM;
6116
6117         path->leave_spinning = 1;
6118         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6119                                       ins, size);
6120         if (ret) {
6121                 btrfs_free_path(path);
6122                 return ret;
6123         }
6124
6125         leaf = path->nodes[0];
6126         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6127                                      struct btrfs_extent_item);
6128         btrfs_set_extent_refs(leaf, extent_item, 1);
6129         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6130         btrfs_set_extent_flags(leaf, extent_item,
6131                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6132         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6133
6134         btrfs_set_tree_block_key(leaf, block_info, key);
6135         btrfs_set_tree_block_level(leaf, block_info, level);
6136
6137         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6138         if (parent > 0) {
6139                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6140                 btrfs_set_extent_inline_ref_type(leaf, iref,
6141                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6142                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6143         } else {
6144                 btrfs_set_extent_inline_ref_type(leaf, iref,
6145                                                  BTRFS_TREE_BLOCK_REF_KEY);
6146                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6147         }
6148
6149         btrfs_mark_buffer_dirty(leaf);
6150         btrfs_free_path(path);
6151
6152         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6153         if (ret) { /* -ENOENT, logic error */
6154                 printk(KERN_ERR "btrfs update block group failed for %llu "
6155                        "%llu\n", (unsigned long long)ins->objectid,
6156                        (unsigned long long)ins->offset);
6157                 BUG();
6158         }
6159         return ret;
6160 }
6161
6162 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6163                                      struct btrfs_root *root,
6164                                      u64 root_objectid, u64 owner,
6165                                      u64 offset, struct btrfs_key *ins)
6166 {
6167         int ret;
6168
6169         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6170
6171         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6172                                          ins->offset, 0,
6173                                          root_objectid, owner, offset,
6174                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6175         return ret;
6176 }
6177
6178 /*
6179  * this is used by the tree logging recovery code.  It records that
6180  * an extent has been allocated and makes sure to clear the free
6181  * space cache bits as well
6182  */
6183 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6184                                    struct btrfs_root *root,
6185                                    u64 root_objectid, u64 owner, u64 offset,
6186                                    struct btrfs_key *ins)
6187 {
6188         int ret;
6189         struct btrfs_block_group_cache *block_group;
6190         struct btrfs_caching_control *caching_ctl;
6191         u64 start = ins->objectid;
6192         u64 num_bytes = ins->offset;
6193
6194         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6195         cache_block_group(block_group, trans, NULL, 0);
6196         caching_ctl = get_caching_control(block_group);
6197
6198         if (!caching_ctl) {
6199                 BUG_ON(!block_group_cache_done(block_group));
6200                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6201                 BUG_ON(ret); /* -ENOMEM */
6202         } else {
6203                 mutex_lock(&caching_ctl->mutex);
6204
6205                 if (start >= caching_ctl->progress) {
6206                         ret = add_excluded_extent(root, start, num_bytes);
6207                         BUG_ON(ret); /* -ENOMEM */
6208                 } else if (start + num_bytes <= caching_ctl->progress) {
6209                         ret = btrfs_remove_free_space(block_group,
6210                                                       start, num_bytes);
6211                         BUG_ON(ret); /* -ENOMEM */
6212                 } else {
6213                         num_bytes = caching_ctl->progress - start;
6214                         ret = btrfs_remove_free_space(block_group,
6215                                                       start, num_bytes);
6216                         BUG_ON(ret); /* -ENOMEM */
6217
6218                         start = caching_ctl->progress;
6219                         num_bytes = ins->objectid + ins->offset -
6220                                     caching_ctl->progress;
6221                         ret = add_excluded_extent(root, start, num_bytes);
6222                         BUG_ON(ret); /* -ENOMEM */
6223                 }
6224
6225                 mutex_unlock(&caching_ctl->mutex);
6226                 put_caching_control(caching_ctl);
6227         }
6228
6229         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6230                                           RESERVE_ALLOC_NO_ACCOUNT);
6231         BUG_ON(ret); /* logic error */
6232         btrfs_put_block_group(block_group);
6233         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6234                                          0, owner, offset, ins, 1);
6235         return ret;
6236 }
6237
6238 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6239                                             struct btrfs_root *root,
6240                                             u64 bytenr, u32 blocksize,
6241                                             int level)
6242 {
6243         struct extent_buffer *buf;
6244
6245         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6246         if (!buf)
6247                 return ERR_PTR(-ENOMEM);
6248         btrfs_set_header_generation(buf, trans->transid);
6249         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6250         btrfs_tree_lock(buf);
6251         clean_tree_block(trans, root, buf);
6252         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6253
6254         btrfs_set_lock_blocking(buf);
6255         btrfs_set_buffer_uptodate(buf);
6256
6257         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6258                 /*
6259                  * we allow two log transactions at a time, use different
6260                  * EXENT bit to differentiate dirty pages.
6261                  */
6262                 if (root->log_transid % 2 == 0)
6263                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6264                                         buf->start + buf->len - 1, GFP_NOFS);
6265                 else
6266                         set_extent_new(&root->dirty_log_pages, buf->start,
6267                                         buf->start + buf->len - 1, GFP_NOFS);
6268         } else {
6269                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6270                          buf->start + buf->len - 1, GFP_NOFS);
6271         }
6272         trans->blocks_used++;
6273         /* this returns a buffer locked for blocking */
6274         return buf;
6275 }
6276
6277 static struct btrfs_block_rsv *
6278 use_block_rsv(struct btrfs_trans_handle *trans,
6279               struct btrfs_root *root, u32 blocksize)
6280 {
6281         struct btrfs_block_rsv *block_rsv;
6282         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6283         int ret;
6284
6285         block_rsv = get_block_rsv(trans, root);
6286
6287         if (block_rsv->size == 0) {
6288                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6289                 /*
6290                  * If we couldn't reserve metadata bytes try and use some from
6291                  * the global reserve.
6292                  */
6293                 if (ret && block_rsv != global_rsv) {
6294                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6295                         if (!ret)
6296                                 return global_rsv;
6297                         return ERR_PTR(ret);
6298                 } else if (ret) {
6299                         return ERR_PTR(ret);
6300                 }
6301                 return block_rsv;
6302         }
6303
6304         ret = block_rsv_use_bytes(block_rsv, blocksize);
6305         if (!ret)
6306                 return block_rsv;
6307         if (ret) {
6308                 static DEFINE_RATELIMIT_STATE(_rs,
6309                                 DEFAULT_RATELIMIT_INTERVAL,
6310                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6311                 if (__ratelimit(&_rs)) {
6312                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6313                         WARN_ON(1);
6314                 }
6315                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6316                 if (!ret) {
6317                         return block_rsv;
6318                 } else if (ret && block_rsv != global_rsv) {
6319                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6320                         if (!ret)
6321                                 return global_rsv;
6322                 }
6323         }
6324
6325         return ERR_PTR(-ENOSPC);
6326 }
6327
6328 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6329                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6330 {
6331         block_rsv_add_bytes(block_rsv, blocksize, 0);
6332         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6333 }
6334
6335 /*
6336  * finds a free extent and does all the dirty work required for allocation
6337  * returns the key for the extent through ins, and a tree buffer for
6338  * the first block of the extent through buf.
6339  *
6340  * returns the tree buffer or NULL.
6341  */
6342 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6343                                         struct btrfs_root *root, u32 blocksize,
6344                                         u64 parent, u64 root_objectid,
6345                                         struct btrfs_disk_key *key, int level,
6346                                         u64 hint, u64 empty_size)
6347 {
6348         struct btrfs_key ins;
6349         struct btrfs_block_rsv *block_rsv;
6350         struct extent_buffer *buf;
6351         u64 flags = 0;
6352         int ret;
6353
6354
6355         block_rsv = use_block_rsv(trans, root, blocksize);
6356         if (IS_ERR(block_rsv))
6357                 return ERR_CAST(block_rsv);
6358
6359         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6360                                    empty_size, hint, &ins, 0);
6361         if (ret) {
6362                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6363                 return ERR_PTR(ret);
6364         }
6365
6366         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6367                                     blocksize, level);
6368         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6369
6370         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6371                 if (parent == 0)
6372                         parent = ins.objectid;
6373                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6374         } else
6375                 BUG_ON(parent > 0);
6376
6377         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6378                 struct btrfs_delayed_extent_op *extent_op;
6379                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6380                 BUG_ON(!extent_op); /* -ENOMEM */
6381                 if (key)
6382                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6383                 else
6384                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6385                 extent_op->flags_to_set = flags;
6386                 extent_op->update_key = 1;
6387                 extent_op->update_flags = 1;
6388                 extent_op->is_data = 0;
6389
6390                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6391                                         ins.objectid,
6392                                         ins.offset, parent, root_objectid,
6393                                         level, BTRFS_ADD_DELAYED_EXTENT,
6394                                         extent_op, 0);
6395                 BUG_ON(ret); /* -ENOMEM */
6396         }
6397         return buf;
6398 }
6399
6400 struct walk_control {
6401         u64 refs[BTRFS_MAX_LEVEL];
6402         u64 flags[BTRFS_MAX_LEVEL];
6403         struct btrfs_key update_progress;
6404         int stage;
6405         int level;
6406         int shared_level;
6407         int update_ref;
6408         int keep_locks;
6409         int reada_slot;
6410         int reada_count;
6411         int for_reloc;
6412 };
6413
6414 #define DROP_REFERENCE  1
6415 #define UPDATE_BACKREF  2
6416
6417 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6418                                      struct btrfs_root *root,
6419                                      struct walk_control *wc,
6420                                      struct btrfs_path *path)
6421 {
6422         u64 bytenr;
6423         u64 generation;
6424         u64 refs;
6425         u64 flags;
6426         u32 nritems;
6427         u32 blocksize;
6428         struct btrfs_key key;
6429         struct extent_buffer *eb;
6430         int ret;
6431         int slot;
6432         int nread = 0;
6433
6434         if (path->slots[wc->level] < wc->reada_slot) {
6435                 wc->reada_count = wc->reada_count * 2 / 3;
6436                 wc->reada_count = max(wc->reada_count, 2);
6437         } else {
6438                 wc->reada_count = wc->reada_count * 3 / 2;
6439                 wc->reada_count = min_t(int, wc->reada_count,
6440                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6441         }
6442
6443         eb = path->nodes[wc->level];
6444         nritems = btrfs_header_nritems(eb);
6445         blocksize = btrfs_level_size(root, wc->level - 1);
6446
6447         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6448                 if (nread >= wc->reada_count)
6449                         break;
6450
6451                 cond_resched();
6452                 bytenr = btrfs_node_blockptr(eb, slot);
6453                 generation = btrfs_node_ptr_generation(eb, slot);
6454
6455                 if (slot == path->slots[wc->level])
6456                         goto reada;
6457
6458                 if (wc->stage == UPDATE_BACKREF &&
6459                     generation <= root->root_key.offset)
6460                         continue;
6461
6462                 /* We don't lock the tree block, it's OK to be racy here */
6463                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6464                                                &refs, &flags);
6465                 /* We don't care about errors in readahead. */
6466                 if (ret < 0)
6467                         continue;
6468                 BUG_ON(refs == 0);
6469
6470                 if (wc->stage == DROP_REFERENCE) {
6471                         if (refs == 1)
6472                                 goto reada;
6473
6474                         if (wc->level == 1 &&
6475                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6476                                 continue;
6477                         if (!wc->update_ref ||
6478                             generation <= root->root_key.offset)
6479                                 continue;
6480                         btrfs_node_key_to_cpu(eb, &key, slot);
6481                         ret = btrfs_comp_cpu_keys(&key,
6482                                                   &wc->update_progress);
6483                         if (ret < 0)
6484                                 continue;
6485                 } else {
6486                         if (wc->level == 1 &&
6487                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6488                                 continue;
6489                 }
6490 reada:
6491                 ret = readahead_tree_block(root, bytenr, blocksize,
6492                                            generation);
6493                 if (ret)
6494                         break;
6495                 nread++;
6496         }
6497         wc->reada_slot = slot;
6498 }
6499
6500 /*
6501  * hepler to process tree block while walking down the tree.
6502  *
6503  * when wc->stage == UPDATE_BACKREF, this function updates
6504  * back refs for pointers in the block.
6505  *
6506  * NOTE: return value 1 means we should stop walking down.
6507  */
6508 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6509                                    struct btrfs_root *root,
6510                                    struct btrfs_path *path,
6511                                    struct walk_control *wc, int lookup_info)
6512 {
6513         int level = wc->level;
6514         struct extent_buffer *eb = path->nodes[level];
6515         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6516         int ret;
6517
6518         if (wc->stage == UPDATE_BACKREF &&
6519             btrfs_header_owner(eb) != root->root_key.objectid)
6520                 return 1;
6521
6522         /*
6523          * when reference count of tree block is 1, it won't increase
6524          * again. once full backref flag is set, we never clear it.
6525          */
6526         if (lookup_info &&
6527             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6528              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6529                 BUG_ON(!path->locks[level]);
6530                 ret = btrfs_lookup_extent_info(trans, root,
6531                                                eb->start, eb->len,
6532                                                &wc->refs[level],
6533                                                &wc->flags[level]);
6534                 BUG_ON(ret == -ENOMEM);
6535                 if (ret)
6536                         return ret;
6537                 BUG_ON(wc->refs[level] == 0);
6538         }
6539
6540         if (wc->stage == DROP_REFERENCE) {
6541                 if (wc->refs[level] > 1)
6542                         return 1;
6543
6544                 if (path->locks[level] && !wc->keep_locks) {
6545                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6546                         path->locks[level] = 0;
6547                 }
6548                 return 0;
6549         }
6550
6551         /* wc->stage == UPDATE_BACKREF */
6552         if (!(wc->flags[level] & flag)) {
6553                 BUG_ON(!path->locks[level]);
6554                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6555                 BUG_ON(ret); /* -ENOMEM */
6556                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6557                 BUG_ON(ret); /* -ENOMEM */
6558                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6559                                                   eb->len, flag, 0);
6560                 BUG_ON(ret); /* -ENOMEM */
6561                 wc->flags[level] |= flag;
6562         }
6563
6564         /*
6565          * the block is shared by multiple trees, so it's not good to
6566          * keep the tree lock
6567          */
6568         if (path->locks[level] && level > 0) {
6569                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6570                 path->locks[level] = 0;
6571         }
6572         return 0;
6573 }
6574
6575 /*
6576  * hepler to process tree block pointer.
6577  *
6578  * when wc->stage == DROP_REFERENCE, this function checks
6579  * reference count of the block pointed to. if the block
6580  * is shared and we need update back refs for the subtree
6581  * rooted at the block, this function changes wc->stage to
6582  * UPDATE_BACKREF. if the block is shared and there is no
6583  * need to update back, this function drops the reference
6584  * to the block.
6585  *
6586  * NOTE: return value 1 means we should stop walking down.
6587  */
6588 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6589                                  struct btrfs_root *root,
6590                                  struct btrfs_path *path,
6591                                  struct walk_control *wc, int *lookup_info)
6592 {
6593         u64 bytenr;
6594         u64 generation;
6595         u64 parent;
6596         u32 blocksize;
6597         struct btrfs_key key;
6598         struct extent_buffer *next;
6599         int level = wc->level;
6600         int reada = 0;
6601         int ret = 0;
6602
6603         generation = btrfs_node_ptr_generation(path->nodes[level],
6604                                                path->slots[level]);
6605         /*
6606          * if the lower level block was created before the snapshot
6607          * was created, we know there is no need to update back refs
6608          * for the subtree
6609          */
6610         if (wc->stage == UPDATE_BACKREF &&
6611             generation <= root->root_key.offset) {
6612                 *lookup_info = 1;
6613                 return 1;
6614         }
6615
6616         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6617         blocksize = btrfs_level_size(root, level - 1);
6618
6619         next = btrfs_find_tree_block(root, bytenr, blocksize);
6620         if (!next) {
6621                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6622                 if (!next)
6623                         return -ENOMEM;
6624                 reada = 1;
6625         }
6626         btrfs_tree_lock(next);
6627         btrfs_set_lock_blocking(next);
6628
6629         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6630                                        &wc->refs[level - 1],
6631                                        &wc->flags[level - 1]);
6632         if (ret < 0) {
6633                 btrfs_tree_unlock(next);
6634                 return ret;
6635         }
6636
6637         BUG_ON(wc->refs[level - 1] == 0);
6638         *lookup_info = 0;
6639
6640         if (wc->stage == DROP_REFERENCE) {
6641                 if (wc->refs[level - 1] > 1) {
6642                         if (level == 1 &&
6643                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6644                                 goto skip;
6645
6646                         if (!wc->update_ref ||
6647                             generation <= root->root_key.offset)
6648                                 goto skip;
6649
6650                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6651                                               path->slots[level]);
6652                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6653                         if (ret < 0)
6654                                 goto skip;
6655
6656                         wc->stage = UPDATE_BACKREF;
6657                         wc->shared_level = level - 1;
6658                 }
6659         } else {
6660                 if (level == 1 &&
6661                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6662                         goto skip;
6663         }
6664
6665         if (!btrfs_buffer_uptodate(next, generation, 0)) {
6666                 btrfs_tree_unlock(next);
6667                 free_extent_buffer(next);
6668                 next = NULL;
6669                 *lookup_info = 1;
6670         }
6671
6672         if (!next) {
6673                 if (reada && level == 1)
6674                         reada_walk_down(trans, root, wc, path);
6675                 next = read_tree_block(root, bytenr, blocksize, generation);
6676                 if (!next)
6677                         return -EIO;
6678                 btrfs_tree_lock(next);
6679                 btrfs_set_lock_blocking(next);
6680         }
6681
6682         level--;
6683         BUG_ON(level != btrfs_header_level(next));
6684         path->nodes[level] = next;
6685         path->slots[level] = 0;
6686         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6687         wc->level = level;
6688         if (wc->level == 1)
6689                 wc->reada_slot = 0;
6690         return 0;
6691 skip:
6692         wc->refs[level - 1] = 0;
6693         wc->flags[level - 1] = 0;
6694         if (wc->stage == DROP_REFERENCE) {
6695                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6696                         parent = path->nodes[level]->start;
6697                 } else {
6698                         BUG_ON(root->root_key.objectid !=
6699                                btrfs_header_owner(path->nodes[level]));
6700                         parent = 0;
6701                 }
6702
6703                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6704                                 root->root_key.objectid, level - 1, 0, 0);
6705                 BUG_ON(ret); /* -ENOMEM */
6706         }
6707         btrfs_tree_unlock(next);
6708         free_extent_buffer(next);
6709         *lookup_info = 1;
6710         return 1;
6711 }
6712
6713 /*
6714  * hepler to process tree block while walking up the tree.
6715  *
6716  * when wc->stage == DROP_REFERENCE, this function drops
6717  * reference count on the block.
6718  *
6719  * when wc->stage == UPDATE_BACKREF, this function changes
6720  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6721  * to UPDATE_BACKREF previously while processing the block.
6722  *
6723  * NOTE: return value 1 means we should stop walking up.
6724  */
6725 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6726                                  struct btrfs_root *root,
6727                                  struct btrfs_path *path,
6728                                  struct walk_control *wc)
6729 {
6730         int ret;
6731         int level = wc->level;
6732         struct extent_buffer *eb = path->nodes[level];
6733         u64 parent = 0;
6734
6735         if (wc->stage == UPDATE_BACKREF) {
6736                 BUG_ON(wc->shared_level < level);
6737                 if (level < wc->shared_level)
6738                         goto out;
6739
6740                 ret = find_next_key(path, level + 1, &wc->update_progress);
6741                 if (ret > 0)
6742                         wc->update_ref = 0;
6743
6744                 wc->stage = DROP_REFERENCE;
6745                 wc->shared_level = -1;
6746                 path->slots[level] = 0;
6747
6748                 /*
6749                  * check reference count again if the block isn't locked.
6750                  * we should start walking down the tree again if reference
6751                  * count is one.
6752                  */
6753                 if (!path->locks[level]) {
6754                         BUG_ON(level == 0);
6755                         btrfs_tree_lock(eb);
6756                         btrfs_set_lock_blocking(eb);
6757                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6758
6759                         ret = btrfs_lookup_extent_info(trans, root,
6760                                                        eb->start, eb->len,
6761                                                        &wc->refs[level],
6762                                                        &wc->flags[level]);
6763                         if (ret < 0) {
6764                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6765                                 return ret;
6766                         }
6767                         BUG_ON(wc->refs[level] == 0);
6768                         if (wc->refs[level] == 1) {
6769                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6770                                 return 1;
6771                         }
6772                 }
6773         }
6774
6775         /* wc->stage == DROP_REFERENCE */
6776         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6777
6778         if (wc->refs[level] == 1) {
6779                 if (level == 0) {
6780                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6781                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6782                                                     wc->for_reloc);
6783                         else
6784                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6785                                                     wc->for_reloc);
6786                         BUG_ON(ret); /* -ENOMEM */
6787                 }
6788                 /* make block locked assertion in clean_tree_block happy */
6789                 if (!path->locks[level] &&
6790                     btrfs_header_generation(eb) == trans->transid) {
6791                         btrfs_tree_lock(eb);
6792                         btrfs_set_lock_blocking(eb);
6793                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6794                 }
6795                 clean_tree_block(trans, root, eb);
6796         }
6797
6798         if (eb == root->node) {
6799                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6800                         parent = eb->start;
6801                 else
6802                         BUG_ON(root->root_key.objectid !=
6803                                btrfs_header_owner(eb));
6804         } else {
6805                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6806                         parent = path->nodes[level + 1]->start;
6807                 else
6808                         BUG_ON(root->root_key.objectid !=
6809                                btrfs_header_owner(path->nodes[level + 1]));
6810         }
6811
6812         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6813 out:
6814         wc->refs[level] = 0;
6815         wc->flags[level] = 0;
6816         return 0;
6817 }
6818
6819 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6820                                    struct btrfs_root *root,
6821                                    struct btrfs_path *path,
6822                                    struct walk_control *wc)
6823 {
6824         int level = wc->level;
6825         int lookup_info = 1;
6826         int ret;
6827
6828         while (level >= 0) {
6829                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6830                 if (ret > 0)
6831                         break;
6832
6833                 if (level == 0)
6834                         break;
6835
6836                 if (path->slots[level] >=
6837                     btrfs_header_nritems(path->nodes[level]))
6838                         break;
6839
6840                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6841                 if (ret > 0) {
6842                         path->slots[level]++;
6843                         continue;
6844                 } else if (ret < 0)
6845                         return ret;
6846                 level = wc->level;
6847         }
6848         return 0;
6849 }
6850
6851 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6852                                  struct btrfs_root *root,
6853                                  struct btrfs_path *path,
6854                                  struct walk_control *wc, int max_level)
6855 {
6856         int level = wc->level;
6857         int ret;
6858
6859         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6860         while (level < max_level && path->nodes[level]) {
6861                 wc->level = level;
6862                 if (path->slots[level] + 1 <
6863                     btrfs_header_nritems(path->nodes[level])) {
6864                         path->slots[level]++;
6865                         return 0;
6866                 } else {
6867                         ret = walk_up_proc(trans, root, path, wc);
6868                         if (ret > 0)
6869                                 return 0;
6870
6871                         if (path->locks[level]) {
6872                                 btrfs_tree_unlock_rw(path->nodes[level],
6873                                                      path->locks[level]);
6874                                 path->locks[level] = 0;
6875                         }
6876                         free_extent_buffer(path->nodes[level]);
6877                         path->nodes[level] = NULL;
6878                         level++;
6879                 }
6880         }
6881         return 1;
6882 }
6883
6884 /*
6885  * drop a subvolume tree.
6886  *
6887  * this function traverses the tree freeing any blocks that only
6888  * referenced by the tree.
6889  *
6890  * when a shared tree block is found. this function decreases its
6891  * reference count by one. if update_ref is true, this function
6892  * also make sure backrefs for the shared block and all lower level
6893  * blocks are properly updated.
6894  */
6895 int btrfs_drop_snapshot(struct btrfs_root *root,
6896                          struct btrfs_block_rsv *block_rsv, int update_ref,
6897                          int for_reloc)
6898 {
6899         struct btrfs_path *path;
6900         struct btrfs_trans_handle *trans;
6901         struct btrfs_root *tree_root = root->fs_info->tree_root;
6902         struct btrfs_root_item *root_item = &root->root_item;
6903         struct walk_control *wc;
6904         struct btrfs_key key;
6905         int err = 0;
6906         int ret;
6907         int level;
6908
6909         path = btrfs_alloc_path();
6910         if (!path) {
6911                 err = -ENOMEM;
6912                 goto out;
6913         }
6914
6915         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6916         if (!wc) {
6917                 btrfs_free_path(path);
6918                 err = -ENOMEM;
6919                 goto out;
6920         }
6921
6922         trans = btrfs_start_transaction(tree_root, 0);
6923         if (IS_ERR(trans)) {
6924                 err = PTR_ERR(trans);
6925                 goto out_free;
6926         }
6927
6928         if (block_rsv)
6929                 trans->block_rsv = block_rsv;
6930
6931         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6932                 level = btrfs_header_level(root->node);
6933                 path->nodes[level] = btrfs_lock_root_node(root);
6934                 btrfs_set_lock_blocking(path->nodes[level]);
6935                 path->slots[level] = 0;
6936                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6937                 memset(&wc->update_progress, 0,
6938                        sizeof(wc->update_progress));
6939         } else {
6940                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6941                 memcpy(&wc->update_progress, &key,
6942                        sizeof(wc->update_progress));
6943
6944                 level = root_item->drop_level;
6945                 BUG_ON(level == 0);
6946                 path->lowest_level = level;
6947                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6948                 path->lowest_level = 0;
6949                 if (ret < 0) {
6950                         err = ret;
6951                         goto out_end_trans;
6952                 }
6953                 WARN_ON(ret > 0);
6954
6955                 /*
6956                  * unlock our path, this is safe because only this
6957                  * function is allowed to delete this snapshot
6958                  */
6959                 btrfs_unlock_up_safe(path, 0);
6960
6961                 level = btrfs_header_level(root->node);
6962                 while (1) {
6963                         btrfs_tree_lock(path->nodes[level]);
6964                         btrfs_set_lock_blocking(path->nodes[level]);
6965
6966                         ret = btrfs_lookup_extent_info(trans, root,
6967                                                 path->nodes[level]->start,
6968                                                 path->nodes[level]->len,
6969                                                 &wc->refs[level],
6970                                                 &wc->flags[level]);
6971                         if (ret < 0) {
6972                                 err = ret;
6973                                 goto out_end_trans;
6974                         }
6975                         BUG_ON(wc->refs[level] == 0);
6976
6977                         if (level == root_item->drop_level)
6978                                 break;
6979
6980                         btrfs_tree_unlock(path->nodes[level]);
6981                         WARN_ON(wc->refs[level] != 1);
6982                         level--;
6983                 }
6984         }
6985
6986         wc->level = level;
6987         wc->shared_level = -1;
6988         wc->stage = DROP_REFERENCE;
6989         wc->update_ref = update_ref;
6990         wc->keep_locks = 0;
6991         wc->for_reloc = for_reloc;
6992         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6993
6994         while (1) {
6995                 ret = walk_down_tree(trans, root, path, wc);
6996                 if (ret < 0) {
6997                         err = ret;
6998                         break;
6999                 }
7000
7001                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7002                 if (ret < 0) {
7003                         err = ret;
7004                         break;
7005                 }
7006
7007                 if (ret > 0) {
7008                         BUG_ON(wc->stage != DROP_REFERENCE);
7009                         break;
7010                 }
7011
7012                 if (wc->stage == DROP_REFERENCE) {
7013                         level = wc->level;
7014                         btrfs_node_key(path->nodes[level],
7015                                        &root_item->drop_progress,
7016                                        path->slots[level]);
7017                         root_item->drop_level = level;
7018                 }
7019
7020                 BUG_ON(wc->level == 0);
7021                 if (btrfs_should_end_transaction(trans, tree_root)) {
7022                         ret = btrfs_update_root(trans, tree_root,
7023                                                 &root->root_key,
7024                                                 root_item);
7025                         if (ret) {
7026                                 btrfs_abort_transaction(trans, tree_root, ret);
7027                                 err = ret;
7028                                 goto out_end_trans;
7029                         }
7030
7031                         btrfs_end_transaction_throttle(trans, tree_root);
7032                         trans = btrfs_start_transaction(tree_root, 0);
7033                         if (IS_ERR(trans)) {
7034                                 err = PTR_ERR(trans);
7035                                 goto out_free;
7036                         }
7037                         if (block_rsv)
7038                                 trans->block_rsv = block_rsv;
7039                 }
7040         }
7041         btrfs_release_path(path);
7042         if (err)
7043                 goto out_end_trans;
7044
7045         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7046         if (ret) {
7047                 btrfs_abort_transaction(trans, tree_root, ret);
7048                 goto out_end_trans;
7049         }
7050
7051         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7052                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
7053                                            NULL, NULL);
7054                 if (ret < 0) {
7055                         btrfs_abort_transaction(trans, tree_root, ret);
7056                         err = ret;
7057                         goto out_end_trans;
7058                 } else if (ret > 0) {
7059                         /* if we fail to delete the orphan item this time
7060                          * around, it'll get picked up the next time.
7061                          *
7062                          * The most common failure here is just -ENOENT.
7063                          */
7064                         btrfs_del_orphan_item(trans, tree_root,
7065                                               root->root_key.objectid);
7066                 }
7067         }
7068
7069         if (root->in_radix) {
7070                 btrfs_free_fs_root(tree_root->fs_info, root);
7071         } else {
7072                 free_extent_buffer(root->node);
7073                 free_extent_buffer(root->commit_root);
7074                 kfree(root);
7075         }
7076 out_end_trans:
7077         btrfs_end_transaction_throttle(trans, tree_root);
7078 out_free:
7079         kfree(wc);
7080         btrfs_free_path(path);
7081 out:
7082         if (err)
7083                 btrfs_std_error(root->fs_info, err);
7084         return err;
7085 }
7086
7087 /*
7088  * drop subtree rooted at tree block 'node'.
7089  *
7090  * NOTE: this function will unlock and release tree block 'node'
7091  * only used by relocation code
7092  */
7093 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7094                         struct btrfs_root *root,
7095                         struct extent_buffer *node,
7096                         struct extent_buffer *parent)
7097 {
7098         struct btrfs_path *path;
7099         struct walk_control *wc;
7100         int level;
7101         int parent_level;
7102         int ret = 0;
7103         int wret;
7104
7105         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7106
7107         path = btrfs_alloc_path();
7108         if (!path)
7109                 return -ENOMEM;
7110
7111         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7112         if (!wc) {
7113                 btrfs_free_path(path);
7114                 return -ENOMEM;
7115         }
7116
7117         btrfs_assert_tree_locked(parent);
7118         parent_level = btrfs_header_level(parent);
7119         extent_buffer_get(parent);
7120         path->nodes[parent_level] = parent;
7121         path->slots[parent_level] = btrfs_header_nritems(parent);
7122
7123         btrfs_assert_tree_locked(node);
7124         level = btrfs_header_level(node);
7125         path->nodes[level] = node;
7126         path->slots[level] = 0;
7127         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7128
7129         wc->refs[parent_level] = 1;
7130         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7131         wc->level = level;
7132         wc->shared_level = -1;
7133         wc->stage = DROP_REFERENCE;
7134         wc->update_ref = 0;
7135         wc->keep_locks = 1;
7136         wc->for_reloc = 1;
7137         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7138
7139         while (1) {
7140                 wret = walk_down_tree(trans, root, path, wc);
7141                 if (wret < 0) {
7142                         ret = wret;
7143                         break;
7144                 }
7145
7146                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7147                 if (wret < 0)
7148                         ret = wret;
7149                 if (wret != 0)
7150                         break;
7151         }
7152
7153         kfree(wc);
7154         btrfs_free_path(path);
7155         return ret;
7156 }
7157
7158 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7159 {
7160         u64 num_devices;
7161         u64 stripped;
7162
7163         /*
7164          * if restripe for this chunk_type is on pick target profile and
7165          * return, otherwise do the usual balance
7166          */
7167         stripped = get_restripe_target(root->fs_info, flags);
7168         if (stripped)
7169                 return extended_to_chunk(stripped);
7170
7171         /*
7172          * we add in the count of missing devices because we want
7173          * to make sure that any RAID levels on a degraded FS
7174          * continue to be honored.
7175          */
7176         num_devices = root->fs_info->fs_devices->rw_devices +
7177                 root->fs_info->fs_devices->missing_devices;
7178
7179         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7180                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7181
7182         if (num_devices == 1) {
7183                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7184                 stripped = flags & ~stripped;
7185
7186                 /* turn raid0 into single device chunks */
7187                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7188                         return stripped;
7189
7190                 /* turn mirroring into duplication */
7191                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7192                              BTRFS_BLOCK_GROUP_RAID10))
7193                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7194         } else {
7195                 /* they already had raid on here, just return */
7196                 if (flags & stripped)
7197                         return flags;
7198
7199                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7200                 stripped = flags & ~stripped;
7201
7202                 /* switch duplicated blocks with raid1 */
7203                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7204                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7205
7206                 /* this is drive concat, leave it alone */
7207         }
7208
7209         return flags;
7210 }
7211
7212 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7213 {
7214         struct btrfs_space_info *sinfo = cache->space_info;
7215         u64 num_bytes;
7216         u64 min_allocable_bytes;
7217         int ret = -ENOSPC;
7218
7219
7220         /*
7221          * We need some metadata space and system metadata space for
7222          * allocating chunks in some corner cases until we force to set
7223          * it to be readonly.
7224          */
7225         if ((sinfo->flags &
7226              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7227             !force)
7228                 min_allocable_bytes = 1 * 1024 * 1024;
7229         else
7230                 min_allocable_bytes = 0;
7231
7232         spin_lock(&sinfo->lock);
7233         spin_lock(&cache->lock);
7234
7235         if (cache->ro) {
7236                 ret = 0;
7237                 goto out;
7238         }
7239
7240         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7241                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7242
7243         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7244             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7245             min_allocable_bytes <= sinfo->total_bytes) {
7246                 sinfo->bytes_readonly += num_bytes;
7247                 cache->ro = 1;
7248                 ret = 0;
7249         }
7250 out:
7251         spin_unlock(&cache->lock);
7252         spin_unlock(&sinfo->lock);
7253         return ret;
7254 }
7255
7256 int btrfs_set_block_group_ro(struct btrfs_root *root,
7257                              struct btrfs_block_group_cache *cache)
7258
7259 {
7260         struct btrfs_trans_handle *trans;
7261         u64 alloc_flags;
7262         int ret;
7263
7264         BUG_ON(cache->ro);
7265
7266         trans = btrfs_join_transaction(root);
7267         if (IS_ERR(trans))
7268                 return PTR_ERR(trans);
7269
7270         alloc_flags = update_block_group_flags(root, cache->flags);
7271         if (alloc_flags != cache->flags) {
7272                 ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7273                                      CHUNK_ALLOC_FORCE);
7274                 if (ret < 0)
7275                         goto out;
7276         }
7277
7278         ret = set_block_group_ro(cache, 0);
7279         if (!ret)
7280                 goto out;
7281         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7282         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7283                              CHUNK_ALLOC_FORCE);
7284         if (ret < 0)
7285                 goto out;
7286         ret = set_block_group_ro(cache, 0);
7287 out:
7288         btrfs_end_transaction(trans, root);
7289         return ret;
7290 }
7291
7292 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7293                             struct btrfs_root *root, u64 type)
7294 {
7295         u64 alloc_flags = get_alloc_profile(root, type);
7296         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7297                               CHUNK_ALLOC_FORCE);
7298 }
7299
7300 /*
7301  * helper to account the unused space of all the readonly block group in the
7302  * list. takes mirrors into account.
7303  */
7304 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7305 {
7306         struct btrfs_block_group_cache *block_group;
7307         u64 free_bytes = 0;
7308         int factor;
7309
7310         list_for_each_entry(block_group, groups_list, list) {
7311                 spin_lock(&block_group->lock);
7312
7313                 if (!block_group->ro) {
7314                         spin_unlock(&block_group->lock);
7315                         continue;
7316                 }
7317
7318                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7319                                           BTRFS_BLOCK_GROUP_RAID10 |
7320                                           BTRFS_BLOCK_GROUP_DUP))
7321                         factor = 2;
7322                 else
7323                         factor = 1;
7324
7325                 free_bytes += (block_group->key.offset -
7326                                btrfs_block_group_used(&block_group->item)) *
7327                                factor;
7328
7329                 spin_unlock(&block_group->lock);
7330         }
7331
7332         return free_bytes;
7333 }
7334
7335 /*
7336  * helper to account the unused space of all the readonly block group in the
7337  * space_info. takes mirrors into account.
7338  */
7339 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7340 {
7341         int i;
7342         u64 free_bytes = 0;
7343
7344         spin_lock(&sinfo->lock);
7345
7346         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7347                 if (!list_empty(&sinfo->block_groups[i]))
7348                         free_bytes += __btrfs_get_ro_block_group_free_space(
7349                                                 &sinfo->block_groups[i]);
7350
7351         spin_unlock(&sinfo->lock);
7352
7353         return free_bytes;
7354 }
7355
7356 void btrfs_set_block_group_rw(struct btrfs_root *root,
7357                               struct btrfs_block_group_cache *cache)
7358 {
7359         struct btrfs_space_info *sinfo = cache->space_info;
7360         u64 num_bytes;
7361
7362         BUG_ON(!cache->ro);
7363
7364         spin_lock(&sinfo->lock);
7365         spin_lock(&cache->lock);
7366         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7367                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7368         sinfo->bytes_readonly -= num_bytes;
7369         cache->ro = 0;
7370         spin_unlock(&cache->lock);
7371         spin_unlock(&sinfo->lock);
7372 }
7373
7374 /*
7375  * checks to see if its even possible to relocate this block group.
7376  *
7377  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7378  * ok to go ahead and try.
7379  */
7380 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7381 {
7382         struct btrfs_block_group_cache *block_group;
7383         struct btrfs_space_info *space_info;
7384         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7385         struct btrfs_device *device;
7386         u64 min_free;
7387         u64 dev_min = 1;
7388         u64 dev_nr = 0;
7389         u64 target;
7390         int index;
7391         int full = 0;
7392         int ret = 0;
7393
7394         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7395
7396         /* odd, couldn't find the block group, leave it alone */
7397         if (!block_group)
7398                 return -1;
7399
7400         min_free = btrfs_block_group_used(&block_group->item);
7401
7402         /* no bytes used, we're good */
7403         if (!min_free)
7404                 goto out;
7405
7406         space_info = block_group->space_info;
7407         spin_lock(&space_info->lock);
7408
7409         full = space_info->full;
7410
7411         /*
7412          * if this is the last block group we have in this space, we can't
7413          * relocate it unless we're able to allocate a new chunk below.
7414          *
7415          * Otherwise, we need to make sure we have room in the space to handle
7416          * all of the extents from this block group.  If we can, we're good
7417          */
7418         if ((space_info->total_bytes != block_group->key.offset) &&
7419             (space_info->bytes_used + space_info->bytes_reserved +
7420              space_info->bytes_pinned + space_info->bytes_readonly +
7421              min_free < space_info->total_bytes)) {
7422                 spin_unlock(&space_info->lock);
7423                 goto out;
7424         }
7425         spin_unlock(&space_info->lock);
7426
7427         /*
7428          * ok we don't have enough space, but maybe we have free space on our
7429          * devices to allocate new chunks for relocation, so loop through our
7430          * alloc devices and guess if we have enough space.  if this block
7431          * group is going to be restriped, run checks against the target
7432          * profile instead of the current one.
7433          */
7434         ret = -1;
7435
7436         /*
7437          * index:
7438          *      0: raid10
7439          *      1: raid1
7440          *      2: dup
7441          *      3: raid0
7442          *      4: single
7443          */
7444         target = get_restripe_target(root->fs_info, block_group->flags);
7445         if (target) {
7446                 index = __get_block_group_index(extended_to_chunk(target));
7447         } else {
7448                 /*
7449                  * this is just a balance, so if we were marked as full
7450                  * we know there is no space for a new chunk
7451                  */
7452                 if (full)
7453                         goto out;
7454
7455                 index = get_block_group_index(block_group);
7456         }
7457
7458         if (index == 0) {
7459                 dev_min = 4;
7460                 /* Divide by 2 */
7461                 min_free >>= 1;
7462         } else if (index == 1) {
7463                 dev_min = 2;
7464         } else if (index == 2) {
7465                 /* Multiply by 2 */
7466                 min_free <<= 1;
7467         } else if (index == 3) {
7468                 dev_min = fs_devices->rw_devices;
7469                 do_div(min_free, dev_min);
7470         }
7471
7472         mutex_lock(&root->fs_info->chunk_mutex);
7473         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7474                 u64 dev_offset;
7475
7476                 /*
7477                  * check to make sure we can actually find a chunk with enough
7478                  * space to fit our block group in.
7479                  */
7480                 if (device->total_bytes > device->bytes_used + min_free) {
7481                         ret = find_free_dev_extent(device, min_free,
7482                                                    &dev_offset, NULL);
7483                         if (!ret)
7484                                 dev_nr++;
7485
7486                         if (dev_nr >= dev_min)
7487                                 break;
7488
7489                         ret = -1;
7490                 }
7491         }
7492         mutex_unlock(&root->fs_info->chunk_mutex);
7493 out:
7494         btrfs_put_block_group(block_group);
7495         return ret;
7496 }
7497
7498 static int find_first_block_group(struct btrfs_root *root,
7499                 struct btrfs_path *path, struct btrfs_key *key)
7500 {
7501         int ret = 0;
7502         struct btrfs_key found_key;
7503         struct extent_buffer *leaf;
7504         int slot;
7505
7506         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7507         if (ret < 0)
7508                 goto out;
7509
7510         while (1) {
7511                 slot = path->slots[0];
7512                 leaf = path->nodes[0];
7513                 if (slot >= btrfs_header_nritems(leaf)) {
7514                         ret = btrfs_next_leaf(root, path);
7515                         if (ret == 0)
7516                                 continue;
7517                         if (ret < 0)
7518                                 goto out;
7519                         break;
7520                 }
7521                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7522
7523                 if (found_key.objectid >= key->objectid &&
7524                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7525                         ret = 0;
7526                         goto out;
7527                 }
7528                 path->slots[0]++;
7529         }
7530 out:
7531         return ret;
7532 }
7533
7534 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7535 {
7536         struct btrfs_block_group_cache *block_group;
7537         u64 last = 0;
7538
7539         while (1) {
7540                 struct inode *inode;
7541
7542                 block_group = btrfs_lookup_first_block_group(info, last);
7543                 while (block_group) {
7544                         spin_lock(&block_group->lock);
7545                         if (block_group->iref)
7546                                 break;
7547                         spin_unlock(&block_group->lock);
7548                         block_group = next_block_group(info->tree_root,
7549                                                        block_group);
7550                 }
7551                 if (!block_group) {
7552                         if (last == 0)
7553                                 break;
7554                         last = 0;
7555                         continue;
7556                 }
7557
7558                 inode = block_group->inode;
7559                 block_group->iref = 0;
7560                 block_group->inode = NULL;
7561                 spin_unlock(&block_group->lock);
7562                 iput(inode);
7563                 last = block_group->key.objectid + block_group->key.offset;
7564                 btrfs_put_block_group(block_group);
7565         }
7566 }
7567
7568 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7569 {
7570         struct btrfs_block_group_cache *block_group;
7571         struct btrfs_space_info *space_info;
7572         struct btrfs_caching_control *caching_ctl;
7573         struct rb_node *n;
7574
7575         down_write(&info->extent_commit_sem);
7576         while (!list_empty(&info->caching_block_groups)) {
7577                 caching_ctl = list_entry(info->caching_block_groups.next,
7578                                          struct btrfs_caching_control, list);
7579                 list_del(&caching_ctl->list);
7580                 put_caching_control(caching_ctl);
7581         }
7582         up_write(&info->extent_commit_sem);
7583
7584         spin_lock(&info->block_group_cache_lock);
7585         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7586                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7587                                        cache_node);
7588                 rb_erase(&block_group->cache_node,
7589                          &info->block_group_cache_tree);
7590                 spin_unlock(&info->block_group_cache_lock);
7591
7592                 down_write(&block_group->space_info->groups_sem);
7593                 list_del(&block_group->list);
7594                 up_write(&block_group->space_info->groups_sem);
7595
7596                 if (block_group->cached == BTRFS_CACHE_STARTED)
7597                         wait_block_group_cache_done(block_group);
7598
7599                 /*
7600                  * We haven't cached this block group, which means we could
7601                  * possibly have excluded extents on this block group.
7602                  */
7603                 if (block_group->cached == BTRFS_CACHE_NO)
7604                         free_excluded_extents(info->extent_root, block_group);
7605
7606                 btrfs_remove_free_space_cache(block_group);
7607                 btrfs_put_block_group(block_group);
7608
7609                 spin_lock(&info->block_group_cache_lock);
7610         }
7611         spin_unlock(&info->block_group_cache_lock);
7612
7613         /* now that all the block groups are freed, go through and
7614          * free all the space_info structs.  This is only called during
7615          * the final stages of unmount, and so we know nobody is
7616          * using them.  We call synchronize_rcu() once before we start,
7617          * just to be on the safe side.
7618          */
7619         synchronize_rcu();
7620
7621         release_global_block_rsv(info);
7622
7623         while(!list_empty(&info->space_info)) {
7624                 space_info = list_entry(info->space_info.next,
7625                                         struct btrfs_space_info,
7626                                         list);
7627                 if (space_info->bytes_pinned > 0 ||
7628                     space_info->bytes_reserved > 0 ||
7629                     space_info->bytes_may_use > 0) {
7630                         WARN_ON(1);
7631                         dump_space_info(space_info, 0, 0);
7632                 }
7633                 list_del(&space_info->list);
7634                 kfree(space_info);
7635         }
7636         return 0;
7637 }
7638
7639 static void __link_block_group(struct btrfs_space_info *space_info,
7640                                struct btrfs_block_group_cache *cache)
7641 {
7642         int index = get_block_group_index(cache);
7643
7644         down_write(&space_info->groups_sem);
7645         list_add_tail(&cache->list, &space_info->block_groups[index]);
7646         up_write(&space_info->groups_sem);
7647 }
7648
7649 int btrfs_read_block_groups(struct btrfs_root *root)
7650 {
7651         struct btrfs_path *path;
7652         int ret;
7653         struct btrfs_block_group_cache *cache;
7654         struct btrfs_fs_info *info = root->fs_info;
7655         struct btrfs_space_info *space_info;
7656         struct btrfs_key key;
7657         struct btrfs_key found_key;
7658         struct extent_buffer *leaf;
7659         int need_clear = 0;
7660         u64 cache_gen;
7661
7662         root = info->extent_root;
7663         key.objectid = 0;
7664         key.offset = 0;
7665         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7666         path = btrfs_alloc_path();
7667         if (!path)
7668                 return -ENOMEM;
7669         path->reada = 1;
7670
7671         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7672         if (btrfs_test_opt(root, SPACE_CACHE) &&
7673             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7674                 need_clear = 1;
7675         if (btrfs_test_opt(root, CLEAR_CACHE))
7676                 need_clear = 1;
7677
7678         while (1) {
7679                 ret = find_first_block_group(root, path, &key);
7680                 if (ret > 0)
7681                         break;
7682                 if (ret != 0)
7683                         goto error;
7684                 leaf = path->nodes[0];
7685                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7686                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7687                 if (!cache) {
7688                         ret = -ENOMEM;
7689                         goto error;
7690                 }
7691                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7692                                                 GFP_NOFS);
7693                 if (!cache->free_space_ctl) {
7694                         kfree(cache);
7695                         ret = -ENOMEM;
7696                         goto error;
7697                 }
7698
7699                 atomic_set(&cache->count, 1);
7700                 spin_lock_init(&cache->lock);
7701                 cache->fs_info = info;
7702                 INIT_LIST_HEAD(&cache->list);
7703                 INIT_LIST_HEAD(&cache->cluster_list);
7704
7705                 if (need_clear) {
7706                         /*
7707                          * When we mount with old space cache, we need to
7708                          * set BTRFS_DC_CLEAR and set dirty flag.
7709                          *
7710                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
7711                          *    truncate the old free space cache inode and
7712                          *    setup a new one.
7713                          * b) Setting 'dirty flag' makes sure that we flush
7714                          *    the new space cache info onto disk.
7715                          */
7716                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7717                         if (btrfs_test_opt(root, SPACE_CACHE))
7718                                 cache->dirty = 1;
7719                 }
7720
7721                 read_extent_buffer(leaf, &cache->item,
7722                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7723                                    sizeof(cache->item));
7724                 memcpy(&cache->key, &found_key, sizeof(found_key));
7725
7726                 key.objectid = found_key.objectid + found_key.offset;
7727                 btrfs_release_path(path);
7728                 cache->flags = btrfs_block_group_flags(&cache->item);
7729                 cache->sectorsize = root->sectorsize;
7730
7731                 btrfs_init_free_space_ctl(cache);
7732
7733                 /*
7734                  * We need to exclude the super stripes now so that the space
7735                  * info has super bytes accounted for, otherwise we'll think
7736                  * we have more space than we actually do.
7737                  */
7738                 exclude_super_stripes(root, cache);
7739
7740                 /*
7741                  * check for two cases, either we are full, and therefore
7742                  * don't need to bother with the caching work since we won't
7743                  * find any space, or we are empty, and we can just add all
7744                  * the space in and be done with it.  This saves us _alot_ of
7745                  * time, particularly in the full case.
7746                  */
7747                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7748                         cache->last_byte_to_unpin = (u64)-1;
7749                         cache->cached = BTRFS_CACHE_FINISHED;
7750                         free_excluded_extents(root, cache);
7751                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7752                         cache->last_byte_to_unpin = (u64)-1;
7753                         cache->cached = BTRFS_CACHE_FINISHED;
7754                         add_new_free_space(cache, root->fs_info,
7755                                            found_key.objectid,
7756                                            found_key.objectid +
7757                                            found_key.offset);
7758                         free_excluded_extents(root, cache);
7759                 }
7760
7761                 ret = update_space_info(info, cache->flags, found_key.offset,
7762                                         btrfs_block_group_used(&cache->item),
7763                                         &space_info);
7764                 BUG_ON(ret); /* -ENOMEM */
7765                 cache->space_info = space_info;
7766                 spin_lock(&cache->space_info->lock);
7767                 cache->space_info->bytes_readonly += cache->bytes_super;
7768                 spin_unlock(&cache->space_info->lock);
7769
7770                 __link_block_group(space_info, cache);
7771
7772                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7773                 BUG_ON(ret); /* Logic error */
7774
7775                 set_avail_alloc_bits(root->fs_info, cache->flags);
7776                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7777                         set_block_group_ro(cache, 1);
7778         }
7779
7780         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7781                 if (!(get_alloc_profile(root, space_info->flags) &
7782                       (BTRFS_BLOCK_GROUP_RAID10 |
7783                        BTRFS_BLOCK_GROUP_RAID1 |
7784                        BTRFS_BLOCK_GROUP_DUP)))
7785                         continue;
7786                 /*
7787                  * avoid allocating from un-mirrored block group if there are
7788                  * mirrored block groups.
7789                  */
7790                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7791                         set_block_group_ro(cache, 1);
7792                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7793                         set_block_group_ro(cache, 1);
7794         }
7795
7796         init_global_block_rsv(info);
7797         ret = 0;
7798 error:
7799         btrfs_free_path(path);
7800         return ret;
7801 }
7802
7803 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7804                            struct btrfs_root *root, u64 bytes_used,
7805                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7806                            u64 size)
7807 {
7808         int ret;
7809         struct btrfs_root *extent_root;
7810         struct btrfs_block_group_cache *cache;
7811
7812         extent_root = root->fs_info->extent_root;
7813
7814         root->fs_info->last_trans_log_full_commit = trans->transid;
7815
7816         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7817         if (!cache)
7818                 return -ENOMEM;
7819         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7820                                         GFP_NOFS);
7821         if (!cache->free_space_ctl) {
7822                 kfree(cache);
7823                 return -ENOMEM;
7824         }
7825
7826         cache->key.objectid = chunk_offset;
7827         cache->key.offset = size;
7828         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7829         cache->sectorsize = root->sectorsize;
7830         cache->fs_info = root->fs_info;
7831
7832         atomic_set(&cache->count, 1);
7833         spin_lock_init(&cache->lock);
7834         INIT_LIST_HEAD(&cache->list);
7835         INIT_LIST_HEAD(&cache->cluster_list);
7836
7837         btrfs_init_free_space_ctl(cache);
7838
7839         btrfs_set_block_group_used(&cache->item, bytes_used);
7840         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7841         cache->flags = type;
7842         btrfs_set_block_group_flags(&cache->item, type);
7843
7844         cache->last_byte_to_unpin = (u64)-1;
7845         cache->cached = BTRFS_CACHE_FINISHED;
7846         exclude_super_stripes(root, cache);
7847
7848         add_new_free_space(cache, root->fs_info, chunk_offset,
7849                            chunk_offset + size);
7850
7851         free_excluded_extents(root, cache);
7852
7853         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7854                                 &cache->space_info);
7855         BUG_ON(ret); /* -ENOMEM */
7856         update_global_block_rsv(root->fs_info);
7857
7858         spin_lock(&cache->space_info->lock);
7859         cache->space_info->bytes_readonly += cache->bytes_super;
7860         spin_unlock(&cache->space_info->lock);
7861
7862         __link_block_group(cache->space_info, cache);
7863
7864         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7865         BUG_ON(ret); /* Logic error */
7866
7867         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7868                                 sizeof(cache->item));
7869         if (ret) {
7870                 btrfs_abort_transaction(trans, extent_root, ret);
7871                 return ret;
7872         }
7873
7874         set_avail_alloc_bits(extent_root->fs_info, type);
7875
7876         return 0;
7877 }
7878
7879 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7880 {
7881         u64 extra_flags = chunk_to_extended(flags) &
7882                                 BTRFS_EXTENDED_PROFILE_MASK;
7883
7884         if (flags & BTRFS_BLOCK_GROUP_DATA)
7885                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7886         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7887                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7888         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7889                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7890 }
7891
7892 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7893                              struct btrfs_root *root, u64 group_start)
7894 {
7895         struct btrfs_path *path;
7896         struct btrfs_block_group_cache *block_group;
7897         struct btrfs_free_cluster *cluster;
7898         struct btrfs_root *tree_root = root->fs_info->tree_root;
7899         struct btrfs_key key;
7900         struct inode *inode;
7901         int ret;
7902         int index;
7903         int factor;
7904
7905         root = root->fs_info->extent_root;
7906
7907         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7908         BUG_ON(!block_group);
7909         BUG_ON(!block_group->ro);
7910
7911         /*
7912          * Free the reserved super bytes from this block group before
7913          * remove it.
7914          */
7915         free_excluded_extents(root, block_group);
7916
7917         memcpy(&key, &block_group->key, sizeof(key));
7918         index = get_block_group_index(block_group);
7919         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7920                                   BTRFS_BLOCK_GROUP_RAID1 |
7921                                   BTRFS_BLOCK_GROUP_RAID10))
7922                 factor = 2;
7923         else
7924                 factor = 1;
7925
7926         /* make sure this block group isn't part of an allocation cluster */
7927         cluster = &root->fs_info->data_alloc_cluster;
7928         spin_lock(&cluster->refill_lock);
7929         btrfs_return_cluster_to_free_space(block_group, cluster);
7930         spin_unlock(&cluster->refill_lock);
7931
7932         /*
7933          * make sure this block group isn't part of a metadata
7934          * allocation cluster
7935          */
7936         cluster = &root->fs_info->meta_alloc_cluster;
7937         spin_lock(&cluster->refill_lock);
7938         btrfs_return_cluster_to_free_space(block_group, cluster);
7939         spin_unlock(&cluster->refill_lock);
7940
7941         path = btrfs_alloc_path();
7942         if (!path) {
7943                 ret = -ENOMEM;
7944                 goto out;
7945         }
7946
7947         inode = lookup_free_space_inode(tree_root, block_group, path);
7948         if (!IS_ERR(inode)) {
7949                 ret = btrfs_orphan_add(trans, inode);
7950                 if (ret) {
7951                         btrfs_add_delayed_iput(inode);
7952                         goto out;
7953                 }
7954                 clear_nlink(inode);
7955                 /* One for the block groups ref */
7956                 spin_lock(&block_group->lock);
7957                 if (block_group->iref) {
7958                         block_group->iref = 0;
7959                         block_group->inode = NULL;
7960                         spin_unlock(&block_group->lock);
7961                         iput(inode);
7962                 } else {
7963                         spin_unlock(&block_group->lock);
7964                 }
7965                 /* One for our lookup ref */
7966                 btrfs_add_delayed_iput(inode);
7967         }
7968
7969         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7970         key.offset = block_group->key.objectid;
7971         key.type = 0;
7972
7973         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7974         if (ret < 0)
7975                 goto out;
7976         if (ret > 0)
7977                 btrfs_release_path(path);
7978         if (ret == 0) {
7979                 ret = btrfs_del_item(trans, tree_root, path);
7980                 if (ret)
7981                         goto out;
7982                 btrfs_release_path(path);
7983         }
7984
7985         spin_lock(&root->fs_info->block_group_cache_lock);
7986         rb_erase(&block_group->cache_node,
7987                  &root->fs_info->block_group_cache_tree);
7988         spin_unlock(&root->fs_info->block_group_cache_lock);
7989
7990         down_write(&block_group->space_info->groups_sem);
7991         /*
7992          * we must use list_del_init so people can check to see if they
7993          * are still on the list after taking the semaphore
7994          */
7995         list_del_init(&block_group->list);
7996         if (list_empty(&block_group->space_info->block_groups[index]))
7997                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7998         up_write(&block_group->space_info->groups_sem);
7999
8000         if (block_group->cached == BTRFS_CACHE_STARTED)
8001                 wait_block_group_cache_done(block_group);
8002
8003         btrfs_remove_free_space_cache(block_group);
8004
8005         spin_lock(&block_group->space_info->lock);
8006         block_group->space_info->total_bytes -= block_group->key.offset;
8007         block_group->space_info->bytes_readonly -= block_group->key.offset;
8008         block_group->space_info->disk_total -= block_group->key.offset * factor;
8009         spin_unlock(&block_group->space_info->lock);
8010
8011         memcpy(&key, &block_group->key, sizeof(key));
8012
8013         btrfs_clear_space_info_full(root->fs_info);
8014
8015         btrfs_put_block_group(block_group);
8016         btrfs_put_block_group(block_group);
8017
8018         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8019         if (ret > 0)
8020                 ret = -EIO;
8021         if (ret < 0)
8022                 goto out;
8023
8024         ret = btrfs_del_item(trans, root, path);
8025 out:
8026         btrfs_free_path(path);
8027         return ret;
8028 }
8029
8030 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8031 {
8032         struct btrfs_space_info *space_info;
8033         struct btrfs_super_block *disk_super;
8034         u64 features;
8035         u64 flags;
8036         int mixed = 0;
8037         int ret;
8038
8039         disk_super = fs_info->super_copy;
8040         if (!btrfs_super_root(disk_super))
8041                 return 1;
8042
8043         features = btrfs_super_incompat_flags(disk_super);
8044         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8045                 mixed = 1;
8046
8047         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8048         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8049         if (ret)
8050                 goto out;
8051
8052         if (mixed) {
8053                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8054                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8055         } else {
8056                 flags = BTRFS_BLOCK_GROUP_METADATA;
8057                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8058                 if (ret)
8059                         goto out;
8060
8061                 flags = BTRFS_BLOCK_GROUP_DATA;
8062                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8063         }
8064 out:
8065         return ret;
8066 }
8067
8068 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8069 {
8070         return unpin_extent_range(root, start, end);
8071 }
8072
8073 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8074                                u64 num_bytes, u64 *actual_bytes)
8075 {
8076         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8077 }
8078
8079 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8080 {
8081         struct btrfs_fs_info *fs_info = root->fs_info;
8082         struct btrfs_block_group_cache *cache = NULL;
8083         u64 group_trimmed;
8084         u64 start;
8085         u64 end;
8086         u64 trimmed = 0;
8087         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8088         int ret = 0;
8089
8090         /*
8091          * try to trim all FS space, our block group may start from non-zero.
8092          */
8093         if (range->len == total_bytes)
8094                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8095         else
8096                 cache = btrfs_lookup_block_group(fs_info, range->start);
8097
8098         while (cache) {
8099                 if (cache->key.objectid >= (range->start + range->len)) {
8100                         btrfs_put_block_group(cache);
8101                         break;
8102                 }
8103
8104                 start = max(range->start, cache->key.objectid);
8105                 end = min(range->start + range->len,
8106                                 cache->key.objectid + cache->key.offset);
8107
8108                 if (end - start >= range->minlen) {
8109                         if (!block_group_cache_done(cache)) {
8110                                 ret = cache_block_group(cache, NULL, root, 0);
8111                                 if (!ret)
8112                                         wait_block_group_cache_done(cache);
8113                         }
8114                         ret = btrfs_trim_block_group(cache,
8115                                                      &group_trimmed,
8116                                                      start,
8117                                                      end,
8118                                                      range->minlen);
8119
8120                         trimmed += group_trimmed;
8121                         if (ret) {
8122                                 btrfs_put_block_group(cache);
8123                                 break;
8124                         }
8125                 }
8126
8127                 cache = next_block_group(fs_info->tree_root, cache);
8128         }
8129
8130         range->len = trimmed;
8131         return ret;
8132 }