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                 spin_unlock(&delayed_refs->lock);
2322
2323                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2324                                           must_insert_reserved);
2325
2326                 btrfs_put_delayed_ref(ref);
2327                 kfree(extent_op);
2328                 count++;
2329
2330                 if (ret) {
2331                         printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
2332                         spin_lock(&delayed_refs->lock);
2333                         return ret;
2334                 }
2335
2336 next:
2337                 do_chunk_alloc(trans, fs_info->extent_root,
2338                                2 * 1024 * 1024,
2339                                btrfs_get_alloc_profile(root, 0),
2340                                CHUNK_ALLOC_NO_FORCE);
2341                 cond_resched();
2342                 spin_lock(&delayed_refs->lock);
2343         }
2344         return count;
2345 }
2346
2347 #ifdef SCRAMBLE_DELAYED_REFS
2348 /*
2349  * Normally delayed refs get processed in ascending bytenr order. This
2350  * correlates in most cases to the order added. To expose dependencies on this
2351  * order, we start to process the tree in the middle instead of the beginning
2352  */
2353 static u64 find_middle(struct rb_root *root)
2354 {
2355         struct rb_node *n = root->rb_node;
2356         struct btrfs_delayed_ref_node *entry;
2357         int alt = 1;
2358         u64 middle;
2359         u64 first = 0, last = 0;
2360
2361         n = rb_first(root);
2362         if (n) {
2363                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2364                 first = entry->bytenr;
2365         }
2366         n = rb_last(root);
2367         if (n) {
2368                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2369                 last = entry->bytenr;
2370         }
2371         n = root->rb_node;
2372
2373         while (n) {
2374                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2375                 WARN_ON(!entry->in_tree);
2376
2377                 middle = entry->bytenr;
2378
2379                 if (alt)
2380                         n = n->rb_left;
2381                 else
2382                         n = n->rb_right;
2383
2384                 alt = 1 - alt;
2385         }
2386         return middle;
2387 }
2388 #endif
2389
2390 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2391                                          struct btrfs_fs_info *fs_info)
2392 {
2393         struct qgroup_update *qgroup_update;
2394         int ret = 0;
2395
2396         if (list_empty(&trans->qgroup_ref_list) !=
2397             !trans->delayed_ref_elem.seq) {
2398                 /* list without seq or seq without list */
2399                 printk(KERN_ERR "btrfs: qgroup accounting update error, list is%s empty, seq is %llu\n",
2400                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2401                         trans->delayed_ref_elem.seq);
2402                 BUG();
2403         }
2404
2405         if (!trans->delayed_ref_elem.seq)
2406                 return 0;
2407
2408         while (!list_empty(&trans->qgroup_ref_list)) {
2409                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2410                                                  struct qgroup_update, list);
2411                 list_del(&qgroup_update->list);
2412                 if (!ret)
2413                         ret = btrfs_qgroup_account_ref(
2414                                         trans, fs_info, qgroup_update->node,
2415                                         qgroup_update->extent_op);
2416                 kfree(qgroup_update);
2417         }
2418
2419         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2420
2421         return ret;
2422 }
2423
2424 /*
2425  * this starts processing the delayed reference count updates and
2426  * extent insertions we have queued up so far.  count can be
2427  * 0, which means to process everything in the tree at the start
2428  * of the run (but not newly added entries), or it can be some target
2429  * number you'd like to process.
2430  *
2431  * Returns 0 on success or if called with an aborted transaction
2432  * Returns <0 on error and aborts the transaction
2433  */
2434 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2435                            struct btrfs_root *root, unsigned long count)
2436 {
2437         struct rb_node *node;
2438         struct btrfs_delayed_ref_root *delayed_refs;
2439         struct btrfs_delayed_ref_node *ref;
2440         struct list_head cluster;
2441         int ret;
2442         u64 delayed_start;
2443         int run_all = count == (unsigned long)-1;
2444         int run_most = 0;
2445         int loops;
2446
2447         /* We'll clean this up in btrfs_cleanup_transaction */
2448         if (trans->aborted)
2449                 return 0;
2450
2451         if (root == root->fs_info->extent_root)
2452                 root = root->fs_info->tree_root;
2453
2454         do_chunk_alloc(trans, root->fs_info->extent_root,
2455                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2456                        CHUNK_ALLOC_NO_FORCE);
2457
2458         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2459
2460         delayed_refs = &trans->transaction->delayed_refs;
2461         INIT_LIST_HEAD(&cluster);
2462 again:
2463         loops = 0;
2464         spin_lock(&delayed_refs->lock);
2465
2466 #ifdef SCRAMBLE_DELAYED_REFS
2467         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2468 #endif
2469
2470         if (count == 0) {
2471                 count = delayed_refs->num_entries * 2;
2472                 run_most = 1;
2473         }
2474         while (1) {
2475                 if (!(run_all || run_most) &&
2476                     delayed_refs->num_heads_ready < 64)
2477                         break;
2478
2479                 /*
2480                  * go find something we can process in the rbtree.  We start at
2481                  * the beginning of the tree, and then build a cluster
2482                  * of refs to process starting at the first one we are able to
2483                  * lock
2484                  */
2485                 delayed_start = delayed_refs->run_delayed_start;
2486                 ret = btrfs_find_ref_cluster(trans, &cluster,
2487                                              delayed_refs->run_delayed_start);
2488                 if (ret)
2489                         break;
2490
2491                 ret = run_clustered_refs(trans, root, &cluster);
2492                 if (ret < 0) {
2493                         spin_unlock(&delayed_refs->lock);
2494                         btrfs_abort_transaction(trans, root, ret);
2495                         return ret;
2496                 }
2497
2498                 count -= min_t(unsigned long, ret, count);
2499
2500                 if (count == 0)
2501                         break;
2502
2503                 if (delayed_start >= delayed_refs->run_delayed_start) {
2504                         if (loops == 0) {
2505                                 /*
2506                                  * btrfs_find_ref_cluster looped. let's do one
2507                                  * more cycle. if we don't run any delayed ref
2508                                  * during that cycle (because we can't because
2509                                  * all of them are blocked), bail out.
2510                                  */
2511                                 loops = 1;
2512                         } else {
2513                                 /*
2514                                  * no runnable refs left, stop trying
2515                                  */
2516                                 BUG_ON(run_all);
2517                                 break;
2518                         }
2519                 }
2520                 if (ret) {
2521                         /* refs were run, let's reset staleness detection */
2522                         loops = 0;
2523                 }
2524         }
2525
2526         if (run_all) {
2527                 node = rb_first(&delayed_refs->root);
2528                 if (!node)
2529                         goto out;
2530                 count = (unsigned long)-1;
2531
2532                 while (node) {
2533                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2534                                        rb_node);
2535                         if (btrfs_delayed_ref_is_head(ref)) {
2536                                 struct btrfs_delayed_ref_head *head;
2537
2538                                 head = btrfs_delayed_node_to_head(ref);
2539                                 atomic_inc(&ref->refs);
2540
2541                                 spin_unlock(&delayed_refs->lock);
2542                                 /*
2543                                  * Mutex was contended, block until it's
2544                                  * released and try again
2545                                  */
2546                                 mutex_lock(&head->mutex);
2547                                 mutex_unlock(&head->mutex);
2548
2549                                 btrfs_put_delayed_ref(ref);
2550                                 cond_resched();
2551                                 goto again;
2552                         }
2553                         node = rb_next(node);
2554                 }
2555                 spin_unlock(&delayed_refs->lock);
2556                 schedule_timeout(1);
2557                 goto again;
2558         }
2559 out:
2560         spin_unlock(&delayed_refs->lock);
2561         assert_qgroups_uptodate(trans);
2562         return 0;
2563 }
2564
2565 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2566                                 struct btrfs_root *root,
2567                                 u64 bytenr, u64 num_bytes, u64 flags,
2568                                 int is_data)
2569 {
2570         struct btrfs_delayed_extent_op *extent_op;
2571         int ret;
2572
2573         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2574         if (!extent_op)
2575                 return -ENOMEM;
2576
2577         extent_op->flags_to_set = flags;
2578         extent_op->update_flags = 1;
2579         extent_op->update_key = 0;
2580         extent_op->is_data = is_data ? 1 : 0;
2581
2582         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2583                                           num_bytes, extent_op);
2584         if (ret)
2585                 kfree(extent_op);
2586         return ret;
2587 }
2588
2589 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2590                                       struct btrfs_root *root,
2591                                       struct btrfs_path *path,
2592                                       u64 objectid, u64 offset, u64 bytenr)
2593 {
2594         struct btrfs_delayed_ref_head *head;
2595         struct btrfs_delayed_ref_node *ref;
2596         struct btrfs_delayed_data_ref *data_ref;
2597         struct btrfs_delayed_ref_root *delayed_refs;
2598         struct rb_node *node;
2599         int ret = 0;
2600
2601         ret = -ENOENT;
2602         delayed_refs = &trans->transaction->delayed_refs;
2603         spin_lock(&delayed_refs->lock);
2604         head = btrfs_find_delayed_ref_head(trans, bytenr);
2605         if (!head)
2606                 goto out;
2607
2608         if (!mutex_trylock(&head->mutex)) {
2609                 atomic_inc(&head->node.refs);
2610                 spin_unlock(&delayed_refs->lock);
2611
2612                 btrfs_release_path(path);
2613
2614                 /*
2615                  * Mutex was contended, block until it's released and let
2616                  * caller try again
2617                  */
2618                 mutex_lock(&head->mutex);
2619                 mutex_unlock(&head->mutex);
2620                 btrfs_put_delayed_ref(&head->node);
2621                 return -EAGAIN;
2622         }
2623
2624         node = rb_prev(&head->node.rb_node);
2625         if (!node)
2626                 goto out_unlock;
2627
2628         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2629
2630         if (ref->bytenr != bytenr)
2631                 goto out_unlock;
2632
2633         ret = 1;
2634         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2635                 goto out_unlock;
2636
2637         data_ref = btrfs_delayed_node_to_data_ref(ref);
2638
2639         node = rb_prev(node);
2640         if (node) {
2641                 int seq = ref->seq;
2642
2643                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2644                 if (ref->bytenr == bytenr && ref->seq == seq)
2645                         goto out_unlock;
2646         }
2647
2648         if (data_ref->root != root->root_key.objectid ||
2649             data_ref->objectid != objectid || data_ref->offset != offset)
2650                 goto out_unlock;
2651
2652         ret = 0;
2653 out_unlock:
2654         mutex_unlock(&head->mutex);
2655 out:
2656         spin_unlock(&delayed_refs->lock);
2657         return ret;
2658 }
2659
2660 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2661                                         struct btrfs_root *root,
2662                                         struct btrfs_path *path,
2663                                         u64 objectid, u64 offset, u64 bytenr)
2664 {
2665         struct btrfs_root *extent_root = root->fs_info->extent_root;
2666         struct extent_buffer *leaf;
2667         struct btrfs_extent_data_ref *ref;
2668         struct btrfs_extent_inline_ref *iref;
2669         struct btrfs_extent_item *ei;
2670         struct btrfs_key key;
2671         u32 item_size;
2672         int ret;
2673
2674         key.objectid = bytenr;
2675         key.offset = (u64)-1;
2676         key.type = BTRFS_EXTENT_ITEM_KEY;
2677
2678         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2679         if (ret < 0)
2680                 goto out;
2681         BUG_ON(ret == 0); /* Corruption */
2682
2683         ret = -ENOENT;
2684         if (path->slots[0] == 0)
2685                 goto out;
2686
2687         path->slots[0]--;
2688         leaf = path->nodes[0];
2689         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2690
2691         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2692                 goto out;
2693
2694         ret = 1;
2695         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2696 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2697         if (item_size < sizeof(*ei)) {
2698                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2699                 goto out;
2700         }
2701 #endif
2702         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2703
2704         if (item_size != sizeof(*ei) +
2705             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2706                 goto out;
2707
2708         if (btrfs_extent_generation(leaf, ei) <=
2709             btrfs_root_last_snapshot(&root->root_item))
2710                 goto out;
2711
2712         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2713         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2714             BTRFS_EXTENT_DATA_REF_KEY)
2715                 goto out;
2716
2717         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2718         if (btrfs_extent_refs(leaf, ei) !=
2719             btrfs_extent_data_ref_count(leaf, ref) ||
2720             btrfs_extent_data_ref_root(leaf, ref) !=
2721             root->root_key.objectid ||
2722             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2723             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2724                 goto out;
2725
2726         ret = 0;
2727 out:
2728         return ret;
2729 }
2730
2731 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2732                           struct btrfs_root *root,
2733                           u64 objectid, u64 offset, u64 bytenr)
2734 {
2735         struct btrfs_path *path;
2736         int ret;
2737         int ret2;
2738
2739         path = btrfs_alloc_path();
2740         if (!path)
2741                 return -ENOENT;
2742
2743         do {
2744                 ret = check_committed_ref(trans, root, path, objectid,
2745                                           offset, bytenr);
2746                 if (ret && ret != -ENOENT)
2747                         goto out;
2748
2749                 ret2 = check_delayed_ref(trans, root, path, objectid,
2750                                          offset, bytenr);
2751         } while (ret2 == -EAGAIN);
2752
2753         if (ret2 && ret2 != -ENOENT) {
2754                 ret = ret2;
2755                 goto out;
2756         }
2757
2758         if (ret != -ENOENT || ret2 != -ENOENT)
2759                 ret = 0;
2760 out:
2761         btrfs_free_path(path);
2762         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2763                 WARN_ON(ret > 0);
2764         return ret;
2765 }
2766
2767 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2768                            struct btrfs_root *root,
2769                            struct extent_buffer *buf,
2770                            int full_backref, int inc, int for_cow)
2771 {
2772         u64 bytenr;
2773         u64 num_bytes;
2774         u64 parent;
2775         u64 ref_root;
2776         u32 nritems;
2777         struct btrfs_key key;
2778         struct btrfs_file_extent_item *fi;
2779         int i;
2780         int level;
2781         int ret = 0;
2782         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2783                             u64, u64, u64, u64, u64, u64, int);
2784
2785         ref_root = btrfs_header_owner(buf);
2786         nritems = btrfs_header_nritems(buf);
2787         level = btrfs_header_level(buf);
2788
2789         if (!root->ref_cows && level == 0)
2790                 return 0;
2791
2792         if (inc)
2793                 process_func = btrfs_inc_extent_ref;
2794         else
2795                 process_func = btrfs_free_extent;
2796
2797         if (full_backref)
2798                 parent = buf->start;
2799         else
2800                 parent = 0;
2801
2802         for (i = 0; i < nritems; i++) {
2803                 if (level == 0) {
2804                         btrfs_item_key_to_cpu(buf, &key, i);
2805                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2806                                 continue;
2807                         fi = btrfs_item_ptr(buf, i,
2808                                             struct btrfs_file_extent_item);
2809                         if (btrfs_file_extent_type(buf, fi) ==
2810                             BTRFS_FILE_EXTENT_INLINE)
2811                                 continue;
2812                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2813                         if (bytenr == 0)
2814                                 continue;
2815
2816                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2817                         key.offset -= btrfs_file_extent_offset(buf, fi);
2818                         ret = process_func(trans, root, bytenr, num_bytes,
2819                                            parent, ref_root, key.objectid,
2820                                            key.offset, for_cow);
2821                         if (ret)
2822                                 goto fail;
2823                 } else {
2824                         bytenr = btrfs_node_blockptr(buf, i);
2825                         num_bytes = btrfs_level_size(root, level - 1);
2826                         ret = process_func(trans, root, bytenr, num_bytes,
2827                                            parent, ref_root, level - 1, 0,
2828                                            for_cow);
2829                         if (ret)
2830                                 goto fail;
2831                 }
2832         }
2833         return 0;
2834 fail:
2835         return ret;
2836 }
2837
2838 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2839                   struct extent_buffer *buf, int full_backref, int for_cow)
2840 {
2841         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2842 }
2843
2844 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2845                   struct extent_buffer *buf, int full_backref, int for_cow)
2846 {
2847         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2848 }
2849
2850 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2851                                  struct btrfs_root *root,
2852                                  struct btrfs_path *path,
2853                                  struct btrfs_block_group_cache *cache)
2854 {
2855         int ret;
2856         struct btrfs_root *extent_root = root->fs_info->extent_root;
2857         unsigned long bi;
2858         struct extent_buffer *leaf;
2859
2860         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2861         if (ret < 0)
2862                 goto fail;
2863         BUG_ON(ret); /* Corruption */
2864
2865         leaf = path->nodes[0];
2866         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2867         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2868         btrfs_mark_buffer_dirty(leaf);
2869         btrfs_release_path(path);
2870 fail:
2871         if (ret) {
2872                 btrfs_abort_transaction(trans, root, ret);
2873                 return ret;
2874         }
2875         return 0;
2876
2877 }
2878
2879 static struct btrfs_block_group_cache *
2880 next_block_group(struct btrfs_root *root,
2881                  struct btrfs_block_group_cache *cache)
2882 {
2883         struct rb_node *node;
2884         spin_lock(&root->fs_info->block_group_cache_lock);
2885         node = rb_next(&cache->cache_node);
2886         btrfs_put_block_group(cache);
2887         if (node) {
2888                 cache = rb_entry(node, struct btrfs_block_group_cache,
2889                                  cache_node);
2890                 btrfs_get_block_group(cache);
2891         } else
2892                 cache = NULL;
2893         spin_unlock(&root->fs_info->block_group_cache_lock);
2894         return cache;
2895 }
2896
2897 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2898                             struct btrfs_trans_handle *trans,
2899                             struct btrfs_path *path)
2900 {
2901         struct btrfs_root *root = block_group->fs_info->tree_root;
2902         struct inode *inode = NULL;
2903         u64 alloc_hint = 0;
2904         int dcs = BTRFS_DC_ERROR;
2905         int num_pages = 0;
2906         int retries = 0;
2907         int ret = 0;
2908
2909         /*
2910          * If this block group is smaller than 100 megs don't bother caching the
2911          * block group.
2912          */
2913         if (block_group->key.offset < (100 * 1024 * 1024)) {
2914                 spin_lock(&block_group->lock);
2915                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2916                 spin_unlock(&block_group->lock);
2917                 return 0;
2918         }
2919
2920 again:
2921         inode = lookup_free_space_inode(root, block_group, path);
2922         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2923                 ret = PTR_ERR(inode);
2924                 btrfs_release_path(path);
2925                 goto out;
2926         }
2927
2928         if (IS_ERR(inode)) {
2929                 BUG_ON(retries);
2930                 retries++;
2931
2932                 if (block_group->ro)
2933                         goto out_free;
2934
2935                 ret = create_free_space_inode(root, trans, block_group, path);
2936                 if (ret)
2937                         goto out_free;
2938                 goto again;
2939         }
2940
2941         /* We've already setup this transaction, go ahead and exit */
2942         if (block_group->cache_generation == trans->transid &&
2943             i_size_read(inode)) {
2944                 dcs = BTRFS_DC_SETUP;
2945                 goto out_put;
2946         }
2947
2948         /*
2949          * We want to set the generation to 0, that way if anything goes wrong
2950          * from here on out we know not to trust this cache when we load up next
2951          * time.
2952          */
2953         BTRFS_I(inode)->generation = 0;
2954         ret = btrfs_update_inode(trans, root, inode);
2955         WARN_ON(ret);
2956
2957         if (i_size_read(inode) > 0) {
2958                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2959                                                       inode);
2960                 if (ret)
2961                         goto out_put;
2962         }
2963
2964         spin_lock(&block_group->lock);
2965         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2966             !btrfs_test_opt(root, SPACE_CACHE)) {
2967                 /*
2968                  * don't bother trying to write stuff out _if_
2969                  * a) we're not cached,
2970                  * b) we're with nospace_cache mount option.
2971                  */
2972                 dcs = BTRFS_DC_WRITTEN;
2973                 spin_unlock(&block_group->lock);
2974                 goto out_put;
2975         }
2976         spin_unlock(&block_group->lock);
2977
2978         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2979         if (!num_pages)
2980                 num_pages = 1;
2981
2982         /*
2983          * Just to make absolutely sure we have enough space, we're going to
2984          * preallocate 12 pages worth of space for each block group.  In
2985          * practice we ought to use at most 8, but we need extra space so we can
2986          * add our header and have a terminator between the extents and the
2987          * bitmaps.
2988          */
2989         num_pages *= 16;
2990         num_pages *= PAGE_CACHE_SIZE;
2991
2992         ret = btrfs_check_data_free_space(inode, num_pages);
2993         if (ret)
2994                 goto out_put;
2995
2996         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2997                                               num_pages, num_pages,
2998                                               &alloc_hint);
2999         if (!ret)
3000                 dcs = BTRFS_DC_SETUP;
3001         btrfs_free_reserved_data_space(inode, num_pages);
3002
3003 out_put:
3004         iput(inode);
3005 out_free:
3006         btrfs_release_path(path);
3007 out:
3008         spin_lock(&block_group->lock);
3009         if (!ret && dcs == BTRFS_DC_SETUP)
3010                 block_group->cache_generation = trans->transid;
3011         block_group->disk_cache_state = dcs;
3012         spin_unlock(&block_group->lock);
3013
3014         return ret;
3015 }
3016
3017 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3018                                    struct btrfs_root *root)
3019 {
3020         struct btrfs_block_group_cache *cache;
3021         int err = 0;
3022         struct btrfs_path *path;
3023         u64 last = 0;
3024
3025         path = btrfs_alloc_path();
3026         if (!path)
3027                 return -ENOMEM;
3028
3029 again:
3030         while (1) {
3031                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3032                 while (cache) {
3033                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3034                                 break;
3035                         cache = next_block_group(root, cache);
3036                 }
3037                 if (!cache) {
3038                         if (last == 0)
3039                                 break;
3040                         last = 0;
3041                         continue;
3042                 }
3043                 err = cache_save_setup(cache, trans, path);
3044                 last = cache->key.objectid + cache->key.offset;
3045                 btrfs_put_block_group(cache);
3046         }
3047
3048         while (1) {
3049                 if (last == 0) {
3050                         err = btrfs_run_delayed_refs(trans, root,
3051                                                      (unsigned long)-1);
3052                         if (err) /* File system offline */
3053                                 goto out;
3054                 }
3055
3056                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3057                 while (cache) {
3058                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3059                                 btrfs_put_block_group(cache);
3060                                 goto again;
3061                         }
3062
3063                         if (cache->dirty)
3064                                 break;
3065                         cache = next_block_group(root, cache);
3066                 }
3067                 if (!cache) {
3068                         if (last == 0)
3069                                 break;
3070                         last = 0;
3071                         continue;
3072                 }
3073
3074                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3075                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3076                 cache->dirty = 0;
3077                 last = cache->key.objectid + cache->key.offset;
3078
3079                 err = write_one_cache_group(trans, root, path, cache);
3080                 if (err) /* File system offline */
3081                         goto out;
3082
3083                 btrfs_put_block_group(cache);
3084         }
3085
3086         while (1) {
3087                 /*
3088                  * I don't think this is needed since we're just marking our
3089                  * preallocated extent as written, but just in case it can't
3090                  * hurt.
3091                  */
3092                 if (last == 0) {
3093                         err = btrfs_run_delayed_refs(trans, root,
3094                                                      (unsigned long)-1);
3095                         if (err) /* File system offline */
3096                                 goto out;
3097                 }
3098
3099                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3100                 while (cache) {
3101                         /*
3102                          * Really this shouldn't happen, but it could if we
3103                          * couldn't write the entire preallocated extent and
3104                          * splitting the extent resulted in a new block.
3105                          */
3106                         if (cache->dirty) {
3107                                 btrfs_put_block_group(cache);
3108                                 goto again;
3109                         }
3110                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3111                                 break;
3112                         cache = next_block_group(root, cache);
3113                 }
3114                 if (!cache) {
3115                         if (last == 0)
3116                                 break;
3117                         last = 0;
3118                         continue;
3119                 }
3120
3121                 err = btrfs_write_out_cache(root, trans, cache, path);
3122
3123                 /*
3124                  * If we didn't have an error then the cache state is still
3125                  * NEED_WRITE, so we can set it to WRITTEN.
3126                  */
3127                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3128                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3129                 last = cache->key.objectid + cache->key.offset;
3130                 btrfs_put_block_group(cache);
3131         }
3132 out:
3133
3134         btrfs_free_path(path);
3135         return err;
3136 }
3137
3138 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3139 {
3140         struct btrfs_block_group_cache *block_group;
3141         int readonly = 0;
3142
3143         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3144         if (!block_group || block_group->ro)
3145                 readonly = 1;
3146         if (block_group)
3147                 btrfs_put_block_group(block_group);
3148         return readonly;
3149 }
3150
3151 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3152                              u64 total_bytes, u64 bytes_used,
3153                              struct btrfs_space_info **space_info)
3154 {
3155         struct btrfs_space_info *found;
3156         int i;
3157         int factor;
3158
3159         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3160                      BTRFS_BLOCK_GROUP_RAID10))
3161                 factor = 2;
3162         else
3163                 factor = 1;
3164
3165         found = __find_space_info(info, flags);
3166         if (found) {
3167                 spin_lock(&found->lock);
3168                 found->total_bytes += total_bytes;
3169                 found->disk_total += total_bytes * factor;
3170                 found->bytes_used += bytes_used;
3171                 found->disk_used += bytes_used * factor;
3172                 found->full = 0;
3173                 spin_unlock(&found->lock);
3174                 *space_info = found;
3175                 return 0;
3176         }
3177         found = kzalloc(sizeof(*found), GFP_NOFS);
3178         if (!found)
3179                 return -ENOMEM;
3180
3181         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3182                 INIT_LIST_HEAD(&found->block_groups[i]);
3183         init_rwsem(&found->groups_sem);
3184         spin_lock_init(&found->lock);
3185         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3186         found->total_bytes = total_bytes;
3187         found->disk_total = total_bytes * factor;
3188         found->bytes_used = bytes_used;
3189         found->disk_used = bytes_used * factor;
3190         found->bytes_pinned = 0;
3191         found->bytes_reserved = 0;
3192         found->bytes_readonly = 0;
3193         found->bytes_may_use = 0;
3194         found->full = 0;
3195         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3196         found->chunk_alloc = 0;
3197         found->flush = 0;
3198         init_waitqueue_head(&found->wait);
3199         *space_info = found;
3200         list_add_rcu(&found->list, &info->space_info);
3201         if (flags & BTRFS_BLOCK_GROUP_DATA)
3202                 info->data_sinfo = found;
3203         return 0;
3204 }
3205
3206 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3207 {
3208         u64 extra_flags = chunk_to_extended(flags) &
3209                                 BTRFS_EXTENDED_PROFILE_MASK;
3210
3211         if (flags & BTRFS_BLOCK_GROUP_DATA)
3212                 fs_info->avail_data_alloc_bits |= extra_flags;
3213         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3214                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3215         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3216                 fs_info->avail_system_alloc_bits |= extra_flags;
3217 }
3218
3219 /*
3220  * returns target flags in extended format or 0 if restripe for this
3221  * chunk_type is not in progress
3222  *
3223  * should be called with either volume_mutex or balance_lock held
3224  */
3225 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3226 {
3227         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3228         u64 target = 0;
3229
3230         if (!bctl)
3231                 return 0;
3232
3233         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3234             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3235                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3236         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3237                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3238                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3239         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3240                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3241                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3242         }
3243
3244         return target;
3245 }
3246
3247 /*
3248  * @flags: available profiles in extended format (see ctree.h)
3249  *
3250  * Returns reduced profile in chunk format.  If profile changing is in
3251  * progress (either running or paused) picks the target profile (if it's
3252  * already available), otherwise falls back to plain reducing.
3253  */
3254 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3255 {
3256         /*
3257          * we add in the count of missing devices because we want
3258          * to make sure that any RAID levels on a degraded FS
3259          * continue to be honored.
3260          */
3261         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3262                 root->fs_info->fs_devices->missing_devices;
3263         u64 target;
3264
3265         /*
3266          * see if restripe for this chunk_type is in progress, if so
3267          * try to reduce to the target profile
3268          */
3269         spin_lock(&root->fs_info->balance_lock);
3270         target = get_restripe_target(root->fs_info, flags);
3271         if (target) {
3272                 /* pick target profile only if it's already available */
3273                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3274                         spin_unlock(&root->fs_info->balance_lock);
3275                         return extended_to_chunk(target);
3276                 }
3277         }
3278         spin_unlock(&root->fs_info->balance_lock);
3279
3280         if (num_devices == 1)
3281                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3282         if (num_devices < 4)
3283                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3284
3285         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3286             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3287                       BTRFS_BLOCK_GROUP_RAID10))) {
3288                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3289         }
3290
3291         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3292             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3293                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3294         }
3295
3296         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3297             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3298              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3299              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3300                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3301         }
3302
3303         return extended_to_chunk(flags);
3304 }
3305
3306 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3307 {
3308         if (flags & BTRFS_BLOCK_GROUP_DATA)
3309                 flags |= root->fs_info->avail_data_alloc_bits;
3310         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3311                 flags |= root->fs_info->avail_system_alloc_bits;
3312         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3313                 flags |= root->fs_info->avail_metadata_alloc_bits;
3314
3315         return btrfs_reduce_alloc_profile(root, flags);
3316 }
3317
3318 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3319 {
3320         u64 flags;
3321
3322         if (data)
3323                 flags = BTRFS_BLOCK_GROUP_DATA;
3324         else if (root == root->fs_info->chunk_root)
3325                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3326         else
3327                 flags = BTRFS_BLOCK_GROUP_METADATA;
3328
3329         return get_alloc_profile(root, flags);
3330 }
3331
3332 /*
3333  * This will check the space that the inode allocates from to make sure we have
3334  * enough space for bytes.
3335  */
3336 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3337 {
3338         struct btrfs_space_info *data_sinfo;
3339         struct btrfs_root *root = BTRFS_I(inode)->root;
3340         struct btrfs_fs_info *fs_info = root->fs_info;
3341         u64 used;
3342         int ret = 0, committed = 0, alloc_chunk = 1;
3343
3344         /* make sure bytes are sectorsize aligned */
3345         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3346
3347         if (root == root->fs_info->tree_root ||
3348             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3349                 alloc_chunk = 0;
3350                 committed = 1;
3351         }
3352
3353         data_sinfo = fs_info->data_sinfo;
3354         if (!data_sinfo)
3355                 goto alloc;
3356
3357 again:
3358         /* make sure we have enough space to handle the data first */
3359         spin_lock(&data_sinfo->lock);
3360         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3361                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3362                 data_sinfo->bytes_may_use;
3363
3364         if (used + bytes > data_sinfo->total_bytes) {
3365                 struct btrfs_trans_handle *trans;
3366
3367                 /*
3368                  * if we don't have enough free bytes in this space then we need
3369                  * to alloc a new chunk.
3370                  */
3371                 if (!data_sinfo->full && alloc_chunk) {
3372                         u64 alloc_target;
3373
3374                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3375                         spin_unlock(&data_sinfo->lock);
3376 alloc:
3377                         alloc_target = btrfs_get_alloc_profile(root, 1);
3378                         trans = btrfs_join_transaction(root);
3379                         if (IS_ERR(trans))
3380                                 return PTR_ERR(trans);
3381
3382                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3383                                              bytes + 2 * 1024 * 1024,
3384                                              alloc_target,
3385                                              CHUNK_ALLOC_NO_FORCE);
3386                         btrfs_end_transaction(trans, root);
3387                         if (ret < 0) {
3388                                 if (ret != -ENOSPC)
3389                                         return ret;
3390                                 else
3391                                         goto commit_trans;
3392                         }
3393
3394                         if (!data_sinfo)
3395                                 data_sinfo = fs_info->data_sinfo;
3396
3397                         goto again;
3398                 }
3399
3400                 /*
3401                  * If we have less pinned bytes than we want to allocate then
3402                  * don't bother committing the transaction, it won't help us.
3403                  */
3404                 if (data_sinfo->bytes_pinned < bytes)
3405                         committed = 1;
3406                 spin_unlock(&data_sinfo->lock);
3407
3408                 /* commit the current transaction and try again */
3409 commit_trans:
3410                 if (!committed &&
3411                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3412                         committed = 1;
3413                         trans = btrfs_join_transaction(root);
3414                         if (IS_ERR(trans))
3415                                 return PTR_ERR(trans);
3416                         ret = btrfs_commit_transaction(trans, root);
3417                         if (ret)
3418                                 return ret;
3419                         goto again;
3420                 }
3421
3422                 return -ENOSPC;
3423         }
3424         data_sinfo->bytes_may_use += bytes;
3425         trace_btrfs_space_reservation(root->fs_info, "space_info",
3426                                       data_sinfo->flags, bytes, 1);
3427         spin_unlock(&data_sinfo->lock);
3428
3429         return 0;
3430 }
3431
3432 /*
3433  * Called if we need to clear a data reservation for this inode.
3434  */
3435 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3436 {
3437         struct btrfs_root *root = BTRFS_I(inode)->root;
3438         struct btrfs_space_info *data_sinfo;
3439
3440         /* make sure bytes are sectorsize aligned */
3441         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3442
3443         data_sinfo = root->fs_info->data_sinfo;
3444         spin_lock(&data_sinfo->lock);
3445         data_sinfo->bytes_may_use -= bytes;
3446         trace_btrfs_space_reservation(root->fs_info, "space_info",
3447                                       data_sinfo->flags, bytes, 0);
3448         spin_unlock(&data_sinfo->lock);
3449 }
3450
3451 static void force_metadata_allocation(struct btrfs_fs_info *info)
3452 {
3453         struct list_head *head = &info->space_info;
3454         struct btrfs_space_info *found;
3455
3456         rcu_read_lock();
3457         list_for_each_entry_rcu(found, head, list) {
3458                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3459                         found->force_alloc = CHUNK_ALLOC_FORCE;
3460         }
3461         rcu_read_unlock();
3462 }
3463
3464 static int should_alloc_chunk(struct btrfs_root *root,
3465                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3466                               int force)
3467 {
3468         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3469         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3470         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3471         u64 thresh;
3472
3473         if (force == CHUNK_ALLOC_FORCE)
3474                 return 1;
3475
3476         /*
3477          * We need to take into account the global rsv because for all intents
3478          * and purposes it's used space.  Don't worry about locking the
3479          * global_rsv, it doesn't change except when the transaction commits.
3480          */
3481         num_allocated += global_rsv->size;
3482
3483         /*
3484          * in limited mode, we want to have some free space up to
3485          * about 1% of the FS size.
3486          */
3487         if (force == CHUNK_ALLOC_LIMITED) {
3488                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3489                 thresh = max_t(u64, 64 * 1024 * 1024,
3490                                div_factor_fine(thresh, 1));
3491
3492                 if (num_bytes - num_allocated < thresh)
3493                         return 1;
3494         }
3495         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3496
3497         /* 256MB or 2% of the FS */
3498         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3499         /* system chunks need a much small threshold */
3500         if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
3501                 thresh = 32 * 1024 * 1024;
3502
3503         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3504                 return 0;
3505         return 1;
3506 }
3507
3508 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3509 {
3510         u64 num_dev;
3511
3512         if (type & BTRFS_BLOCK_GROUP_RAID10 ||
3513             type & BTRFS_BLOCK_GROUP_RAID0)
3514                 num_dev = root->fs_info->fs_devices->rw_devices;
3515         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3516                 num_dev = 2;
3517         else
3518                 num_dev = 1;    /* DUP or single */
3519
3520         /* metadata for updaing devices and chunk tree */
3521         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3522 }
3523
3524 static void check_system_chunk(struct btrfs_trans_handle *trans,
3525                                struct btrfs_root *root, u64 type)
3526 {
3527         struct btrfs_space_info *info;
3528         u64 left;
3529         u64 thresh;
3530
3531         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3532         spin_lock(&info->lock);
3533         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3534                 info->bytes_reserved - info->bytes_readonly;
3535         spin_unlock(&info->lock);
3536
3537         thresh = get_system_chunk_thresh(root, type);
3538         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3539                 printk(KERN_INFO "left=%llu, need=%llu, flags=%llu\n",
3540                        left, thresh, type);
3541                 dump_space_info(info, 0, 0);
3542         }
3543
3544         if (left < thresh) {
3545                 u64 flags;
3546
3547                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3548                 btrfs_alloc_chunk(trans, root, flags);
3549         }
3550 }
3551
3552 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3553                           struct btrfs_root *extent_root, u64 alloc_bytes,
3554                           u64 flags, int force)
3555 {
3556         struct btrfs_space_info *space_info;
3557         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3558         int wait_for_alloc = 0;
3559         int ret = 0;
3560
3561         space_info = __find_space_info(extent_root->fs_info, flags);
3562         if (!space_info) {
3563                 ret = update_space_info(extent_root->fs_info, flags,
3564                                         0, 0, &space_info);
3565                 BUG_ON(ret); /* -ENOMEM */
3566         }
3567         BUG_ON(!space_info); /* Logic error */
3568
3569 again:
3570         spin_lock(&space_info->lock);
3571         if (force < space_info->force_alloc)
3572                 force = space_info->force_alloc;
3573         if (space_info->full) {
3574                 spin_unlock(&space_info->lock);
3575                 return 0;
3576         }
3577
3578         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3579                 spin_unlock(&space_info->lock);
3580                 return 0;
3581         } else if (space_info->chunk_alloc) {
3582                 wait_for_alloc = 1;
3583         } else {
3584                 space_info->chunk_alloc = 1;
3585         }
3586
3587         spin_unlock(&space_info->lock);
3588
3589         mutex_lock(&fs_info->chunk_mutex);
3590
3591         /*
3592          * The chunk_mutex is held throughout the entirety of a chunk
3593          * allocation, so once we've acquired the chunk_mutex we know that the
3594          * other guy is done and we need to recheck and see if we should
3595          * allocate.
3596          */
3597         if (wait_for_alloc) {
3598                 mutex_unlock(&fs_info->chunk_mutex);
3599                 wait_for_alloc = 0;
3600                 goto again;
3601         }
3602
3603         /*
3604          * If we have mixed data/metadata chunks we want to make sure we keep
3605          * allocating mixed chunks instead of individual chunks.
3606          */
3607         if (btrfs_mixed_space_info(space_info))
3608                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3609
3610         /*
3611          * if we're doing a data chunk, go ahead and make sure that
3612          * we keep a reasonable number of metadata chunks allocated in the
3613          * FS as well.
3614          */
3615         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3616                 fs_info->data_chunk_allocations++;
3617                 if (!(fs_info->data_chunk_allocations %
3618                       fs_info->metadata_ratio))
3619                         force_metadata_allocation(fs_info);
3620         }
3621
3622         /*
3623          * Check if we have enough space in SYSTEM chunk because we may need
3624          * to update devices.
3625          */
3626         check_system_chunk(trans, extent_root, flags);
3627
3628         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3629         if (ret < 0 && ret != -ENOSPC)
3630                 goto out;
3631
3632         spin_lock(&space_info->lock);
3633         if (ret)
3634                 space_info->full = 1;
3635         else
3636                 ret = 1;
3637
3638         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3639         space_info->chunk_alloc = 0;
3640         spin_unlock(&space_info->lock);
3641 out:
3642         mutex_unlock(&fs_info->chunk_mutex);
3643         return ret;
3644 }
3645
3646 /*
3647  * shrink metadata reservation for delalloc
3648  */
3649 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3650                             bool wait_ordered)
3651 {
3652         struct btrfs_block_rsv *block_rsv;
3653         struct btrfs_space_info *space_info;
3654         struct btrfs_trans_handle *trans;
3655         u64 delalloc_bytes;
3656         u64 max_reclaim;
3657         long time_left;
3658         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3659         int loops = 0;
3660
3661         trans = (struct btrfs_trans_handle *)current->journal_info;
3662         block_rsv = &root->fs_info->delalloc_block_rsv;
3663         space_info = block_rsv->space_info;
3664
3665         smp_mb();
3666         delalloc_bytes = root->fs_info->delalloc_bytes;
3667         if (delalloc_bytes == 0) {
3668                 if (trans)
3669                         return;
3670                 btrfs_wait_ordered_extents(root, 0, 0);
3671                 return;
3672         }
3673
3674         while (delalloc_bytes && loops < 3) {
3675                 max_reclaim = min(delalloc_bytes, to_reclaim);
3676                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3677                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3678                                                WB_REASON_FS_FREE_SPACE);
3679
3680                 spin_lock(&space_info->lock);
3681                 if (space_info->bytes_used + space_info->bytes_reserved +
3682                     space_info->bytes_pinned + space_info->bytes_readonly +
3683                     space_info->bytes_may_use + orig <=
3684                     space_info->total_bytes) {
3685                         spin_unlock(&space_info->lock);
3686                         break;
3687                 }
3688                 spin_unlock(&space_info->lock);
3689
3690                 loops++;
3691                 if (wait_ordered && !trans) {
3692                         btrfs_wait_ordered_extents(root, 0, 0);
3693                 } else {
3694                         time_left = schedule_timeout_killable(1);
3695                         if (time_left)
3696                                 break;
3697                 }
3698                 smp_mb();
3699                 delalloc_bytes = root->fs_info->delalloc_bytes;
3700         }
3701 }
3702
3703 /**
3704  * maybe_commit_transaction - possibly commit the transaction if its ok to
3705  * @root - the root we're allocating for
3706  * @bytes - the number of bytes we want to reserve
3707  * @force - force the commit
3708  *
3709  * This will check to make sure that committing the transaction will actually
3710  * get us somewhere and then commit the transaction if it does.  Otherwise it
3711  * will return -ENOSPC.
3712  */
3713 static int may_commit_transaction(struct btrfs_root *root,
3714                                   struct btrfs_space_info *space_info,
3715                                   u64 bytes, int force)
3716 {
3717         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3718         struct btrfs_trans_handle *trans;
3719
3720         trans = (struct btrfs_trans_handle *)current->journal_info;
3721         if (trans)
3722                 return -EAGAIN;
3723
3724         if (force)
3725                 goto commit;
3726
3727         /* See if there is enough pinned space to make this reservation */
3728         spin_lock(&space_info->lock);
3729         if (space_info->bytes_pinned >= bytes) {
3730                 spin_unlock(&space_info->lock);
3731                 goto commit;
3732         }
3733         spin_unlock(&space_info->lock);
3734
3735         /*
3736          * See if there is some space in the delayed insertion reservation for
3737          * this reservation.
3738          */
3739         if (space_info != delayed_rsv->space_info)
3740                 return -ENOSPC;
3741
3742         spin_lock(&space_info->lock);
3743         spin_lock(&delayed_rsv->lock);
3744         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3745                 spin_unlock(&delayed_rsv->lock);
3746                 spin_unlock(&space_info->lock);
3747                 return -ENOSPC;
3748         }
3749         spin_unlock(&delayed_rsv->lock);
3750         spin_unlock(&space_info->lock);
3751
3752 commit:
3753         trans = btrfs_join_transaction(root);
3754         if (IS_ERR(trans))
3755                 return -ENOSPC;
3756
3757         return btrfs_commit_transaction(trans, root);
3758 }
3759
3760 enum flush_state {
3761         FLUSH_DELALLOC          =       1,
3762         FLUSH_DELALLOC_WAIT     =       2,
3763         FLUSH_DELAYED_ITEMS_NR  =       3,
3764         FLUSH_DELAYED_ITEMS     =       4,
3765         COMMIT_TRANS            =       5,
3766 };
3767
3768 static int flush_space(struct btrfs_root *root,
3769                        struct btrfs_space_info *space_info, u64 num_bytes,
3770                        u64 orig_bytes, int state)
3771 {
3772         struct btrfs_trans_handle *trans;
3773         int nr;
3774         int ret = 0;
3775
3776         switch (state) {
3777         case FLUSH_DELALLOC:
3778         case FLUSH_DELALLOC_WAIT:
3779                 shrink_delalloc(root, num_bytes, orig_bytes,
3780                                 state == FLUSH_DELALLOC_WAIT);
3781                 break;
3782         case FLUSH_DELAYED_ITEMS_NR:
3783         case FLUSH_DELAYED_ITEMS:
3784                 if (state == FLUSH_DELAYED_ITEMS_NR) {
3785                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
3786
3787                         nr = (int)div64_u64(num_bytes, bytes);
3788                         if (!nr)
3789                                 nr = 1;
3790                         nr *= 2;
3791                 } else {
3792                         nr = -1;
3793                 }
3794                 trans = btrfs_join_transaction(root);
3795                 if (IS_ERR(trans)) {
3796                         ret = PTR_ERR(trans);
3797                         break;
3798                 }
3799                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
3800                 btrfs_end_transaction(trans, root);
3801                 break;
3802         case COMMIT_TRANS:
3803                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3804                 break;
3805         default:
3806                 ret = -ENOSPC;
3807                 break;
3808         }
3809
3810         return ret;
3811 }
3812 /**
3813  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3814  * @root - the root we're allocating for
3815  * @block_rsv - the block_rsv we're allocating for
3816  * @orig_bytes - the number of bytes we want
3817  * @flush - wether or not we can flush to make our reservation
3818  *
3819  * This will reserve orgi_bytes number of bytes from the space info associated
3820  * with the block_rsv.  If there is not enough space it will make an attempt to
3821  * flush out space to make room.  It will do this by flushing delalloc if
3822  * possible or committing the transaction.  If flush is 0 then no attempts to
3823  * regain reservations will be made and this will fail if there is not enough
3824  * space already.
3825  */
3826 static int reserve_metadata_bytes(struct btrfs_root *root,
3827                                   struct btrfs_block_rsv *block_rsv,
3828                                   u64 orig_bytes, int flush)
3829 {
3830         struct btrfs_space_info *space_info = block_rsv->space_info;
3831         u64 used;
3832         u64 num_bytes = orig_bytes;
3833         int flush_state = FLUSH_DELALLOC;
3834         int ret = 0;
3835         bool flushing = false;
3836         bool committed = false;
3837
3838 again:
3839         ret = 0;
3840         spin_lock(&space_info->lock);
3841         /*
3842          * We only want to wait if somebody other than us is flushing and we are
3843          * actually alloed to flush.
3844          */
3845         while (flush && !flushing && space_info->flush) {
3846                 spin_unlock(&space_info->lock);
3847                 /*
3848                  * If we have a trans handle we can't wait because the flusher
3849                  * may have to commit the transaction, which would mean we would
3850                  * deadlock since we are waiting for the flusher to finish, but
3851                  * hold the current transaction open.
3852                  */
3853                 if (current->journal_info)
3854                         return -EAGAIN;
3855                 ret = wait_event_killable(space_info->wait, !space_info->flush);
3856                 /* Must have been killed, return */
3857                 if (ret)
3858                         return -EINTR;
3859
3860                 spin_lock(&space_info->lock);
3861         }
3862
3863         ret = -ENOSPC;
3864         used = space_info->bytes_used + space_info->bytes_reserved +
3865                 space_info->bytes_pinned + space_info->bytes_readonly +
3866                 space_info->bytes_may_use;
3867
3868         /*
3869          * The idea here is that we've not already over-reserved the block group
3870          * then we can go ahead and save our reservation first and then start
3871          * flushing if we need to.  Otherwise if we've already overcommitted
3872          * lets start flushing stuff first and then come back and try to make
3873          * our reservation.
3874          */
3875         if (used <= space_info->total_bytes) {
3876                 if (used + orig_bytes <= space_info->total_bytes) {
3877                         space_info->bytes_may_use += orig_bytes;
3878                         trace_btrfs_space_reservation(root->fs_info,
3879                                 "space_info", space_info->flags, orig_bytes, 1);
3880                         ret = 0;
3881                 } else {
3882                         /*
3883                          * Ok set num_bytes to orig_bytes since we aren't
3884                          * overocmmitted, this way we only try and reclaim what
3885                          * we need.
3886                          */
3887                         num_bytes = orig_bytes;
3888                 }
3889         } else {
3890                 /*
3891                  * Ok we're over committed, set num_bytes to the overcommitted
3892                  * amount plus the amount of bytes that we need for this
3893                  * reservation.
3894                  */
3895                 num_bytes = used - space_info->total_bytes +
3896                         (orig_bytes * 2);
3897         }
3898
3899         if (ret) {
3900                 u64 profile = btrfs_get_alloc_profile(root, 0);
3901                 u64 avail;
3902
3903                 /*
3904                  * If we have a lot of space that's pinned, don't bother doing
3905                  * the overcommit dance yet and just commit the transaction.
3906                  */
3907                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3908                 do_div(avail, 10);
3909                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3910                         space_info->flush = 1;
3911                         flushing = true;
3912                         spin_unlock(&space_info->lock);
3913                         ret = may_commit_transaction(root, space_info,
3914                                                      orig_bytes, 1);
3915                         if (ret)
3916                                 goto out;
3917                         committed = true;
3918                         goto again;
3919                 }
3920
3921                 spin_lock(&root->fs_info->free_chunk_lock);
3922                 avail = root->fs_info->free_chunk_space;
3923
3924                 /*
3925                  * If we have dup, raid1 or raid10 then only half of the free
3926                  * space is actually useable.
3927                  */
3928                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3929                                BTRFS_BLOCK_GROUP_RAID1 |
3930                                BTRFS_BLOCK_GROUP_RAID10))
3931                         avail >>= 1;
3932
3933                 /*
3934                  * If we aren't flushing don't let us overcommit too much, say
3935                  * 1/8th of the space.  If we can flush, let it overcommit up to
3936                  * 1/2 of the space.
3937                  */
3938                 if (flush)
3939                         avail >>= 3;
3940                 else
3941                         avail >>= 1;
3942                  spin_unlock(&root->fs_info->free_chunk_lock);
3943
3944                 if (used + num_bytes < space_info->total_bytes + avail) {
3945                         space_info->bytes_may_use += orig_bytes;
3946                         trace_btrfs_space_reservation(root->fs_info,
3947                                 "space_info", space_info->flags, orig_bytes, 1);
3948                         ret = 0;
3949                 }
3950         }
3951
3952         /*
3953          * Couldn't make our reservation, save our place so while we're trying
3954          * to reclaim space we can actually use it instead of somebody else
3955          * stealing it from us.
3956          */
3957         if (ret && flush) {
3958                 flushing = true;
3959                 space_info->flush = 1;
3960         }
3961
3962         spin_unlock(&space_info->lock);
3963
3964         if (!ret || !flush)
3965                 goto out;
3966
3967         ret = flush_space(root, space_info, num_bytes, orig_bytes,
3968                           flush_state);
3969         flush_state++;
3970         if (!ret)
3971                 goto again;
3972         else if (flush_state <= COMMIT_TRANS)
3973                 goto again;
3974
3975 out:
3976         if (flushing) {
3977                 spin_lock(&space_info->lock);
3978                 space_info->flush = 0;
3979                 wake_up_all(&space_info->wait);
3980                 spin_unlock(&space_info->lock);
3981         }
3982         return ret;
3983 }
3984
3985 static struct btrfs_block_rsv *get_block_rsv(
3986                                         const struct btrfs_trans_handle *trans,
3987                                         const struct btrfs_root *root)
3988 {
3989         struct btrfs_block_rsv *block_rsv = NULL;
3990
3991         if (root->ref_cows)
3992                 block_rsv = trans->block_rsv;
3993
3994         if (root == root->fs_info->csum_root && trans->adding_csums)
3995                 block_rsv = trans->block_rsv;
3996
3997         if (!block_rsv)
3998                 block_rsv = root->block_rsv;
3999
4000         if (!block_rsv)
4001                 block_rsv = &root->fs_info->empty_block_rsv;
4002
4003         return block_rsv;
4004 }
4005
4006 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4007                                u64 num_bytes)
4008 {
4009         int ret = -ENOSPC;
4010         spin_lock(&block_rsv->lock);
4011         if (block_rsv->reserved >= num_bytes) {
4012                 block_rsv->reserved -= num_bytes;
4013                 if (block_rsv->reserved < block_rsv->size)
4014                         block_rsv->full = 0;
4015                 ret = 0;
4016         }
4017         spin_unlock(&block_rsv->lock);
4018         return ret;
4019 }
4020
4021 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4022                                 u64 num_bytes, int update_size)
4023 {
4024         spin_lock(&block_rsv->lock);
4025         block_rsv->reserved += num_bytes;
4026         if (update_size)
4027                 block_rsv->size += num_bytes;
4028         else if (block_rsv->reserved >= block_rsv->size)
4029                 block_rsv->full = 1;
4030         spin_unlock(&block_rsv->lock);
4031 }
4032
4033 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4034                                     struct btrfs_block_rsv *block_rsv,
4035                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4036 {
4037         struct btrfs_space_info *space_info = block_rsv->space_info;
4038
4039         spin_lock(&block_rsv->lock);
4040         if (num_bytes == (u64)-1)
4041                 num_bytes = block_rsv->size;
4042         block_rsv->size -= num_bytes;
4043         if (block_rsv->reserved >= block_rsv->size) {
4044                 num_bytes = block_rsv->reserved - block_rsv->size;
4045                 block_rsv->reserved = block_rsv->size;
4046                 block_rsv->full = 1;
4047         } else {
4048                 num_bytes = 0;
4049         }
4050         spin_unlock(&block_rsv->lock);
4051
4052         if (num_bytes > 0) {
4053                 if (dest) {
4054                         spin_lock(&dest->lock);
4055                         if (!dest->full) {
4056                                 u64 bytes_to_add;
4057
4058                                 bytes_to_add = dest->size - dest->reserved;
4059                                 bytes_to_add = min(num_bytes, bytes_to_add);
4060                                 dest->reserved += bytes_to_add;
4061                                 if (dest->reserved >= dest->size)
4062                                         dest->full = 1;
4063                                 num_bytes -= bytes_to_add;
4064                         }
4065                         spin_unlock(&dest->lock);
4066                 }
4067                 if (num_bytes) {
4068                         spin_lock(&space_info->lock);
4069                         space_info->bytes_may_use -= num_bytes;
4070                         trace_btrfs_space_reservation(fs_info, "space_info",
4071                                         space_info->flags, num_bytes, 0);
4072                         space_info->reservation_progress++;
4073                         spin_unlock(&space_info->lock);
4074                 }
4075         }
4076 }
4077
4078 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4079                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4080 {
4081         int ret;
4082
4083         ret = block_rsv_use_bytes(src, num_bytes);
4084         if (ret)
4085                 return ret;
4086
4087         block_rsv_add_bytes(dst, num_bytes, 1);
4088         return 0;
4089 }
4090
4091 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
4092 {
4093         memset(rsv, 0, sizeof(*rsv));
4094         spin_lock_init(&rsv->lock);
4095 }
4096
4097 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
4098 {
4099         struct btrfs_block_rsv *block_rsv;
4100         struct btrfs_fs_info *fs_info = root->fs_info;
4101
4102         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4103         if (!block_rsv)
4104                 return NULL;
4105
4106         btrfs_init_block_rsv(block_rsv);
4107         block_rsv->space_info = __find_space_info(fs_info,
4108                                                   BTRFS_BLOCK_GROUP_METADATA);
4109         return block_rsv;
4110 }
4111
4112 void btrfs_free_block_rsv(struct btrfs_root *root,
4113                           struct btrfs_block_rsv *rsv)
4114 {
4115         btrfs_block_rsv_release(root, rsv, (u64)-1);
4116         kfree(rsv);
4117 }
4118
4119 static inline int __block_rsv_add(struct btrfs_root *root,
4120                                   struct btrfs_block_rsv *block_rsv,
4121                                   u64 num_bytes, int flush)
4122 {
4123         int ret;
4124
4125         if (num_bytes == 0)
4126                 return 0;
4127
4128         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4129         if (!ret) {
4130                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4131                 return 0;
4132         }
4133
4134         return ret;
4135 }
4136
4137 int btrfs_block_rsv_add(struct btrfs_root *root,
4138                         struct btrfs_block_rsv *block_rsv,
4139                         u64 num_bytes)
4140 {
4141         return __block_rsv_add(root, block_rsv, num_bytes, 1);
4142 }
4143
4144 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
4145                                 struct btrfs_block_rsv *block_rsv,
4146                                 u64 num_bytes)
4147 {
4148         return __block_rsv_add(root, block_rsv, num_bytes, 0);
4149 }
4150
4151 int btrfs_block_rsv_check(struct btrfs_root *root,
4152                           struct btrfs_block_rsv *block_rsv, int min_factor)
4153 {
4154         u64 num_bytes = 0;
4155         int ret = -ENOSPC;
4156
4157         if (!block_rsv)
4158                 return 0;
4159
4160         spin_lock(&block_rsv->lock);
4161         num_bytes = div_factor(block_rsv->size, min_factor);
4162         if (block_rsv->reserved >= num_bytes)
4163                 ret = 0;
4164         spin_unlock(&block_rsv->lock);
4165
4166         return ret;
4167 }
4168
4169 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4170                                            struct btrfs_block_rsv *block_rsv,
4171                                            u64 min_reserved, int flush)
4172 {
4173         u64 num_bytes = 0;
4174         int ret = -ENOSPC;
4175
4176         if (!block_rsv)
4177                 return 0;
4178
4179         spin_lock(&block_rsv->lock);
4180         num_bytes = min_reserved;
4181         if (block_rsv->reserved >= num_bytes)
4182                 ret = 0;
4183         else
4184                 num_bytes -= block_rsv->reserved;
4185         spin_unlock(&block_rsv->lock);
4186
4187         if (!ret)
4188                 return 0;
4189
4190         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4191         if (!ret) {
4192                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4193                 return 0;
4194         }
4195
4196         return ret;
4197 }
4198
4199 int btrfs_block_rsv_refill(struct btrfs_root *root,
4200                            struct btrfs_block_rsv *block_rsv,
4201                            u64 min_reserved)
4202 {
4203         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4204 }
4205
4206 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4207                                    struct btrfs_block_rsv *block_rsv,
4208                                    u64 min_reserved)
4209 {
4210         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4211 }
4212
4213 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4214                             struct btrfs_block_rsv *dst_rsv,
4215                             u64 num_bytes)
4216 {
4217         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4218 }
4219
4220 void btrfs_block_rsv_release(struct btrfs_root *root,
4221                              struct btrfs_block_rsv *block_rsv,
4222                              u64 num_bytes)
4223 {
4224         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4225         if (global_rsv->full || global_rsv == block_rsv ||
4226             block_rsv->space_info != global_rsv->space_info)
4227                 global_rsv = NULL;
4228         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4229                                 num_bytes);
4230 }
4231
4232 /*
4233  * helper to calculate size of global block reservation.
4234  * the desired value is sum of space used by extent tree,
4235  * checksum tree and root tree
4236  */
4237 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4238 {
4239         struct btrfs_space_info *sinfo;
4240         u64 num_bytes;
4241         u64 meta_used;
4242         u64 data_used;
4243         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4244
4245         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4246         spin_lock(&sinfo->lock);
4247         data_used = sinfo->bytes_used;
4248         spin_unlock(&sinfo->lock);
4249
4250         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4251         spin_lock(&sinfo->lock);
4252         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4253                 data_used = 0;
4254         meta_used = sinfo->bytes_used;
4255         spin_unlock(&sinfo->lock);
4256
4257         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4258                     csum_size * 2;
4259         num_bytes += div64_u64(data_used + meta_used, 50);
4260
4261         if (num_bytes * 3 > meta_used)
4262                 num_bytes = div64_u64(meta_used, 3);
4263
4264         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4265 }
4266
4267 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4268 {
4269         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4270         struct btrfs_space_info *sinfo = block_rsv->space_info;
4271         u64 num_bytes;
4272
4273         num_bytes = calc_global_metadata_size(fs_info);
4274
4275         spin_lock(&sinfo->lock);
4276         spin_lock(&block_rsv->lock);
4277
4278         block_rsv->size = num_bytes;
4279
4280         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4281                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4282                     sinfo->bytes_may_use;
4283
4284         if (sinfo->total_bytes > num_bytes) {
4285                 num_bytes = sinfo->total_bytes - num_bytes;
4286                 block_rsv->reserved += num_bytes;
4287                 sinfo->bytes_may_use += num_bytes;
4288                 trace_btrfs_space_reservation(fs_info, "space_info",
4289                                       sinfo->flags, num_bytes, 1);
4290         }
4291
4292         if (block_rsv->reserved >= block_rsv->size) {
4293                 num_bytes = block_rsv->reserved - block_rsv->size;
4294                 sinfo->bytes_may_use -= num_bytes;
4295                 trace_btrfs_space_reservation(fs_info, "space_info",
4296                                       sinfo->flags, num_bytes, 0);
4297                 sinfo->reservation_progress++;
4298                 block_rsv->reserved = block_rsv->size;
4299                 block_rsv->full = 1;
4300         }
4301
4302         spin_unlock(&block_rsv->lock);
4303         spin_unlock(&sinfo->lock);
4304 }
4305
4306 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4307 {
4308         struct btrfs_space_info *space_info;
4309
4310         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4311         fs_info->chunk_block_rsv.space_info = space_info;
4312
4313         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4314         fs_info->global_block_rsv.space_info = space_info;
4315         fs_info->delalloc_block_rsv.space_info = space_info;
4316         fs_info->trans_block_rsv.space_info = space_info;
4317         fs_info->empty_block_rsv.space_info = space_info;
4318         fs_info->delayed_block_rsv.space_info = space_info;
4319
4320         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4321         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4322         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4323         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4324         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4325
4326         update_global_block_rsv(fs_info);
4327 }
4328
4329 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4330 {
4331         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4332                                 (u64)-1);
4333         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4334         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4335         WARN_ON(fs_info->trans_block_rsv.size > 0);
4336         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4337         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4338         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4339         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4340         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4341 }
4342
4343 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4344                                   struct btrfs_root *root)
4345 {
4346         if (!trans->block_rsv)
4347                 return;
4348
4349         if (!trans->bytes_reserved)
4350                 return;
4351
4352         trace_btrfs_space_reservation(root->fs_info, "transaction",
4353                                       trans->transid, trans->bytes_reserved, 0);
4354         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4355         trans->bytes_reserved = 0;
4356 }
4357
4358 /* Can only return 0 or -ENOSPC */
4359 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4360                                   struct inode *inode)
4361 {
4362         struct btrfs_root *root = BTRFS_I(inode)->root;
4363         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4364         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4365
4366         /*
4367          * We need to hold space in order to delete our orphan item once we've
4368          * added it, so this takes the reservation so we can release it later
4369          * when we are truly done with the orphan item.
4370          */
4371         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4372         trace_btrfs_space_reservation(root->fs_info, "orphan",
4373                                       btrfs_ino(inode), num_bytes, 1);
4374         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4375 }
4376
4377 void btrfs_orphan_release_metadata(struct inode *inode)
4378 {
4379         struct btrfs_root *root = BTRFS_I(inode)->root;
4380         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4381         trace_btrfs_space_reservation(root->fs_info, "orphan",
4382                                       btrfs_ino(inode), num_bytes, 0);
4383         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4384 }
4385
4386 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4387                                 struct btrfs_pending_snapshot *pending)
4388 {
4389         struct btrfs_root *root = pending->root;
4390         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4391         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4392         /*
4393          * two for root back/forward refs, two for directory entries
4394          * and one for root of the snapshot.
4395          */
4396         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4397         dst_rsv->space_info = src_rsv->space_info;
4398         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4399 }
4400
4401 /**
4402  * drop_outstanding_extent - drop an outstanding extent
4403  * @inode: the inode we're dropping the extent for
4404  *
4405  * This is called when we are freeing up an outstanding extent, either called
4406  * after an error or after an extent is written.  This will return the number of
4407  * reserved extents that need to be freed.  This must be called with
4408  * BTRFS_I(inode)->lock held.
4409  */
4410 static unsigned drop_outstanding_extent(struct inode *inode)
4411 {
4412         unsigned drop_inode_space = 0;
4413         unsigned dropped_extents = 0;
4414
4415         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4416         BTRFS_I(inode)->outstanding_extents--;
4417
4418         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4419             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4420                                &BTRFS_I(inode)->runtime_flags))
4421                 drop_inode_space = 1;
4422
4423         /*
4424          * If we have more or the same amount of outsanding extents than we have
4425          * reserved then we need to leave the reserved extents count alone.
4426          */
4427         if (BTRFS_I(inode)->outstanding_extents >=
4428             BTRFS_I(inode)->reserved_extents)
4429                 return drop_inode_space;
4430
4431         dropped_extents = BTRFS_I(inode)->reserved_extents -
4432                 BTRFS_I(inode)->outstanding_extents;
4433         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4434         return dropped_extents + drop_inode_space;
4435 }
4436
4437 /**
4438  * calc_csum_metadata_size - return the amount of metada space that must be
4439  *      reserved/free'd for the given bytes.
4440  * @inode: the inode we're manipulating
4441  * @num_bytes: the number of bytes in question
4442  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4443  *
4444  * This adjusts the number of csum_bytes in the inode and then returns the
4445  * correct amount of metadata that must either be reserved or freed.  We
4446  * calculate how many checksums we can fit into one leaf and then divide the
4447  * number of bytes that will need to be checksumed by this value to figure out
4448  * how many checksums will be required.  If we are adding bytes then the number
4449  * may go up and we will return the number of additional bytes that must be
4450  * reserved.  If it is going down we will return the number of bytes that must
4451  * be freed.
4452  *
4453  * This must be called with BTRFS_I(inode)->lock held.
4454  */
4455 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4456                                    int reserve)
4457 {
4458         struct btrfs_root *root = BTRFS_I(inode)->root;
4459         u64 csum_size;
4460         int num_csums_per_leaf;
4461         int num_csums;
4462         int old_csums;
4463
4464         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4465             BTRFS_I(inode)->csum_bytes == 0)
4466                 return 0;
4467
4468         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4469         if (reserve)
4470                 BTRFS_I(inode)->csum_bytes += num_bytes;
4471         else
4472                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4473         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4474         num_csums_per_leaf = (int)div64_u64(csum_size,
4475                                             sizeof(struct btrfs_csum_item) +
4476                                             sizeof(struct btrfs_disk_key));
4477         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4478         num_csums = num_csums + num_csums_per_leaf - 1;
4479         num_csums = num_csums / num_csums_per_leaf;
4480
4481         old_csums = old_csums + num_csums_per_leaf - 1;
4482         old_csums = old_csums / num_csums_per_leaf;
4483
4484         /* No change, no need to reserve more */
4485         if (old_csums == num_csums)
4486                 return 0;
4487
4488         if (reserve)
4489                 return btrfs_calc_trans_metadata_size(root,
4490                                                       num_csums - old_csums);
4491
4492         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4493 }
4494
4495 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4496 {
4497         struct btrfs_root *root = BTRFS_I(inode)->root;
4498         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4499         u64 to_reserve = 0;
4500         u64 csum_bytes;
4501         unsigned nr_extents = 0;
4502         int extra_reserve = 0;
4503         int flush = 1;
4504         int ret;
4505
4506         /* Need to be holding the i_mutex here if we aren't free space cache */
4507         if (btrfs_is_free_space_inode(inode))
4508                 flush = 0;
4509
4510         if (flush && btrfs_transaction_in_commit(root->fs_info))
4511                 schedule_timeout(1);
4512
4513         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4514         num_bytes = ALIGN(num_bytes, root->sectorsize);
4515
4516         spin_lock(&BTRFS_I(inode)->lock);
4517         BTRFS_I(inode)->outstanding_extents++;
4518
4519         if (BTRFS_I(inode)->outstanding_extents >
4520             BTRFS_I(inode)->reserved_extents)
4521                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4522                         BTRFS_I(inode)->reserved_extents;
4523
4524         /*
4525          * Add an item to reserve for updating the inode when we complete the
4526          * delalloc io.
4527          */
4528         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4529                       &BTRFS_I(inode)->runtime_flags)) {
4530                 nr_extents++;
4531                 extra_reserve = 1;
4532         }
4533
4534         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4535         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4536         csum_bytes = BTRFS_I(inode)->csum_bytes;
4537         spin_unlock(&BTRFS_I(inode)->lock);
4538
4539         if (root->fs_info->quota_enabled) {
4540                 ret = btrfs_qgroup_reserve(root, num_bytes +
4541                                            nr_extents * root->leafsize);
4542                 if (ret) {
4543                         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4544                         return ret;
4545                 }
4546         }
4547
4548         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4549         if (ret) {
4550                 u64 to_free = 0;
4551                 unsigned dropped;
4552
4553                 spin_lock(&BTRFS_I(inode)->lock);
4554                 dropped = drop_outstanding_extent(inode);
4555                 /*
4556                  * If the inodes csum_bytes is the same as the original
4557                  * csum_bytes then we know we haven't raced with any free()ers
4558                  * so we can just reduce our inodes csum bytes and carry on.
4559                  * Otherwise we have to do the normal free thing to account for
4560                  * the case that the free side didn't free up its reserve
4561                  * because of this outstanding reservation.
4562                  */
4563                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4564                         calc_csum_metadata_size(inode, num_bytes, 0);
4565                 else
4566                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4567                 spin_unlock(&BTRFS_I(inode)->lock);
4568                 if (dropped)
4569                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4570
4571                 if (to_free) {
4572                         btrfs_block_rsv_release(root, block_rsv, to_free);
4573                         trace_btrfs_space_reservation(root->fs_info,
4574                                                       "delalloc",
4575                                                       btrfs_ino(inode),
4576                                                       to_free, 0);
4577                 }
4578                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4579                 return ret;
4580         }
4581
4582         spin_lock(&BTRFS_I(inode)->lock);
4583         if (extra_reserve) {
4584                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4585                         &BTRFS_I(inode)->runtime_flags);
4586                 nr_extents--;
4587         }
4588         BTRFS_I(inode)->reserved_extents += nr_extents;
4589         spin_unlock(&BTRFS_I(inode)->lock);
4590         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4591
4592         if (to_reserve)
4593                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4594                                               btrfs_ino(inode), to_reserve, 1);
4595         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4596
4597         return 0;
4598 }
4599
4600 /**
4601  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4602  * @inode: the inode to release the reservation for
4603  * @num_bytes: the number of bytes we're releasing
4604  *
4605  * This will release the metadata reservation for an inode.  This can be called
4606  * once we complete IO for a given set of bytes to release their metadata
4607  * reservations.
4608  */
4609 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4610 {
4611         struct btrfs_root *root = BTRFS_I(inode)->root;
4612         u64 to_free = 0;
4613         unsigned dropped;
4614
4615         num_bytes = ALIGN(num_bytes, root->sectorsize);
4616         spin_lock(&BTRFS_I(inode)->lock);
4617         dropped = drop_outstanding_extent(inode);
4618
4619         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4620         spin_unlock(&BTRFS_I(inode)->lock);
4621         if (dropped > 0)
4622                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4623
4624         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4625                                       btrfs_ino(inode), to_free, 0);
4626         if (root->fs_info->quota_enabled) {
4627                 btrfs_qgroup_free(root, num_bytes +
4628                                         dropped * root->leafsize);
4629         }
4630
4631         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4632                                 to_free);
4633 }
4634
4635 /**
4636  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4637  * @inode: inode we're writing to
4638  * @num_bytes: the number of bytes we want to allocate
4639  *
4640  * This will do the following things
4641  *
4642  * o reserve space in the data space info for num_bytes
4643  * o reserve space in the metadata space info based on number of outstanding
4644  *   extents and how much csums will be needed
4645  * o add to the inodes ->delalloc_bytes
4646  * o add it to the fs_info's delalloc inodes list.
4647  *
4648  * This will return 0 for success and -ENOSPC if there is no space left.
4649  */
4650 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4651 {
4652         int ret;
4653
4654         ret = btrfs_check_data_free_space(inode, num_bytes);
4655         if (ret)
4656                 return ret;
4657
4658         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4659         if (ret) {
4660                 btrfs_free_reserved_data_space(inode, num_bytes);
4661                 return ret;
4662         }
4663
4664         return 0;
4665 }
4666
4667 /**
4668  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4669  * @inode: inode we're releasing space for
4670  * @num_bytes: the number of bytes we want to free up
4671  *
4672  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4673  * called in the case that we don't need the metadata AND data reservations
4674  * anymore.  So if there is an error or we insert an inline extent.
4675  *
4676  * This function will release the metadata space that was not used and will
4677  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4678  * list if there are no delalloc bytes left.
4679  */
4680 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4681 {
4682         btrfs_delalloc_release_metadata(inode, num_bytes);
4683         btrfs_free_reserved_data_space(inode, num_bytes);
4684 }
4685
4686 static int update_block_group(struct btrfs_trans_handle *trans,
4687                               struct btrfs_root *root,
4688                               u64 bytenr, u64 num_bytes, int alloc)
4689 {
4690         struct btrfs_block_group_cache *cache = NULL;
4691         struct btrfs_fs_info *info = root->fs_info;
4692         u64 total = num_bytes;
4693         u64 old_val;
4694         u64 byte_in_group;
4695         int factor;
4696
4697         /* block accounting for super block */
4698         spin_lock(&info->delalloc_lock);
4699         old_val = btrfs_super_bytes_used(info->super_copy);
4700         if (alloc)
4701                 old_val += num_bytes;
4702         else
4703                 old_val -= num_bytes;
4704         btrfs_set_super_bytes_used(info->super_copy, old_val);
4705         spin_unlock(&info->delalloc_lock);
4706
4707         while (total) {
4708                 cache = btrfs_lookup_block_group(info, bytenr);
4709                 if (!cache)
4710                         return -ENOENT;
4711                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4712                                     BTRFS_BLOCK_GROUP_RAID1 |
4713                                     BTRFS_BLOCK_GROUP_RAID10))
4714                         factor = 2;
4715                 else
4716                         factor = 1;
4717                 /*
4718                  * If this block group has free space cache written out, we
4719                  * need to make sure to load it if we are removing space.  This
4720                  * is because we need the unpinning stage to actually add the
4721                  * space back to the block group, otherwise we will leak space.
4722                  */
4723                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4724                         cache_block_group(cache, trans, NULL, 1);
4725
4726                 byte_in_group = bytenr - cache->key.objectid;
4727                 WARN_ON(byte_in_group > cache->key.offset);
4728
4729                 spin_lock(&cache->space_info->lock);
4730                 spin_lock(&cache->lock);
4731
4732                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4733                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4734                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4735
4736                 cache->dirty = 1;
4737                 old_val = btrfs_block_group_used(&cache->item);
4738                 num_bytes = min(total, cache->key.offset - byte_in_group);
4739                 if (alloc) {
4740                         old_val += num_bytes;
4741                         btrfs_set_block_group_used(&cache->item, old_val);
4742                         cache->reserved -= num_bytes;
4743                         cache->space_info->bytes_reserved -= num_bytes;
4744                         cache->space_info->bytes_used += num_bytes;
4745                         cache->space_info->disk_used += num_bytes * factor;
4746                         spin_unlock(&cache->lock);
4747                         spin_unlock(&cache->space_info->lock);
4748                 } else {
4749                         old_val -= num_bytes;
4750                         btrfs_set_block_group_used(&cache->item, old_val);
4751                         cache->pinned += num_bytes;
4752                         cache->space_info->bytes_pinned += num_bytes;
4753                         cache->space_info->bytes_used -= num_bytes;
4754                         cache->space_info->disk_used -= num_bytes * factor;
4755                         spin_unlock(&cache->lock);
4756                         spin_unlock(&cache->space_info->lock);
4757
4758                         set_extent_dirty(info->pinned_extents,
4759                                          bytenr, bytenr + num_bytes - 1,
4760                                          GFP_NOFS | __GFP_NOFAIL);
4761                 }
4762                 btrfs_put_block_group(cache);
4763                 total -= num_bytes;
4764                 bytenr += num_bytes;
4765         }
4766         return 0;
4767 }
4768
4769 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4770 {
4771         struct btrfs_block_group_cache *cache;
4772         u64 bytenr;
4773
4774         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4775         if (!cache)
4776                 return 0;
4777
4778         bytenr = cache->key.objectid;
4779         btrfs_put_block_group(cache);
4780
4781         return bytenr;
4782 }
4783
4784 static int pin_down_extent(struct btrfs_root *root,
4785                            struct btrfs_block_group_cache *cache,
4786                            u64 bytenr, u64 num_bytes, int reserved)
4787 {
4788         spin_lock(&cache->space_info->lock);
4789         spin_lock(&cache->lock);
4790         cache->pinned += num_bytes;
4791         cache->space_info->bytes_pinned += num_bytes;
4792         if (reserved) {
4793                 cache->reserved -= num_bytes;
4794                 cache->space_info->bytes_reserved -= num_bytes;
4795         }
4796         spin_unlock(&cache->lock);
4797         spin_unlock(&cache->space_info->lock);
4798
4799         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4800                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4801         return 0;
4802 }
4803
4804 /*
4805  * this function must be called within transaction
4806  */
4807 int btrfs_pin_extent(struct btrfs_root *root,
4808                      u64 bytenr, u64 num_bytes, int reserved)
4809 {
4810         struct btrfs_block_group_cache *cache;
4811
4812         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4813         BUG_ON(!cache); /* Logic error */
4814
4815         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4816
4817         btrfs_put_block_group(cache);
4818         return 0;
4819 }
4820
4821 /*
4822  * this function must be called within transaction
4823  */
4824 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4825                                     struct btrfs_root *root,
4826                                     u64 bytenr, u64 num_bytes)
4827 {
4828         struct btrfs_block_group_cache *cache;
4829
4830         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4831         BUG_ON(!cache); /* Logic error */
4832
4833         /*
4834          * pull in the free space cache (if any) so that our pin
4835          * removes the free space from the cache.  We have load_only set
4836          * to one because the slow code to read in the free extents does check
4837          * the pinned extents.
4838          */
4839         cache_block_group(cache, trans, root, 1);
4840
4841         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4842
4843         /* remove us from the free space cache (if we're there at all) */
4844         btrfs_remove_free_space(cache, bytenr, num_bytes);
4845         btrfs_put_block_group(cache);
4846         return 0;
4847 }
4848
4849 /**
4850  * btrfs_update_reserved_bytes - update the block_group and space info counters
4851  * @cache:      The cache we are manipulating
4852  * @num_bytes:  The number of bytes in question
4853  * @reserve:    One of the reservation enums
4854  *
4855  * This is called by the allocator when it reserves space, or by somebody who is
4856  * freeing space that was never actually used on disk.  For example if you
4857  * reserve some space for a new leaf in transaction A and before transaction A
4858  * commits you free that leaf, you call this with reserve set to 0 in order to
4859  * clear the reservation.
4860  *
4861  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4862  * ENOSPC accounting.  For data we handle the reservation through clearing the
4863  * delalloc bits in the io_tree.  We have to do this since we could end up
4864  * allocating less disk space for the amount of data we have reserved in the
4865  * case of compression.
4866  *
4867  * If this is a reservation and the block group has become read only we cannot
4868  * make the reservation and return -EAGAIN, otherwise this function always
4869  * succeeds.
4870  */
4871 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4872                                        u64 num_bytes, int reserve)
4873 {
4874         struct btrfs_space_info *space_info = cache->space_info;
4875         int ret = 0;
4876
4877         spin_lock(&space_info->lock);
4878         spin_lock(&cache->lock);
4879         if (reserve != RESERVE_FREE) {
4880                 if (cache->ro) {
4881                         ret = -EAGAIN;
4882                 } else {
4883                         cache->reserved += num_bytes;
4884                         space_info->bytes_reserved += num_bytes;
4885                         if (reserve == RESERVE_ALLOC) {
4886                                 trace_btrfs_space_reservation(cache->fs_info,
4887                                                 "space_info", space_info->flags,
4888                                                 num_bytes, 0);
4889                                 space_info->bytes_may_use -= num_bytes;
4890                         }
4891                 }
4892         } else {
4893                 if (cache->ro)
4894                         space_info->bytes_readonly += num_bytes;
4895                 cache->reserved -= num_bytes;
4896                 space_info->bytes_reserved -= num_bytes;
4897                 space_info->reservation_progress++;
4898         }
4899         spin_unlock(&cache->lock);
4900         spin_unlock(&space_info->lock);
4901         return ret;
4902 }
4903
4904 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4905                                 struct btrfs_root *root)
4906 {
4907         struct btrfs_fs_info *fs_info = root->fs_info;
4908         struct btrfs_caching_control *next;
4909         struct btrfs_caching_control *caching_ctl;
4910         struct btrfs_block_group_cache *cache;
4911
4912         down_write(&fs_info->extent_commit_sem);
4913
4914         list_for_each_entry_safe(caching_ctl, next,
4915                                  &fs_info->caching_block_groups, list) {
4916                 cache = caching_ctl->block_group;
4917                 if (block_group_cache_done(cache)) {
4918                         cache->last_byte_to_unpin = (u64)-1;
4919                         list_del_init(&caching_ctl->list);
4920                         put_caching_control(caching_ctl);
4921                 } else {
4922                         cache->last_byte_to_unpin = caching_ctl->progress;
4923                 }
4924         }
4925
4926         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4927                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4928         else
4929                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4930
4931         up_write(&fs_info->extent_commit_sem);
4932
4933         update_global_block_rsv(fs_info);
4934 }
4935
4936 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4937 {
4938         struct btrfs_fs_info *fs_info = root->fs_info;
4939         struct btrfs_block_group_cache *cache = NULL;
4940         u64 len;
4941
4942         while (start <= end) {
4943                 if (!cache ||
4944                     start >= cache->key.objectid + cache->key.offset) {
4945                         if (cache)
4946                                 btrfs_put_block_group(cache);
4947                         cache = btrfs_lookup_block_group(fs_info, start);
4948                         BUG_ON(!cache); /* Logic error */
4949                 }
4950
4951                 len = cache->key.objectid + cache->key.offset - start;
4952                 len = min(len, end + 1 - start);
4953
4954                 if (start < cache->last_byte_to_unpin) {
4955                         len = min(len, cache->last_byte_to_unpin - start);
4956                         btrfs_add_free_space(cache, start, len);
4957                 }
4958
4959                 start += len;
4960
4961                 spin_lock(&cache->space_info->lock);
4962                 spin_lock(&cache->lock);
4963                 cache->pinned -= len;
4964                 cache->space_info->bytes_pinned -= len;
4965                 if (cache->ro)
4966                         cache->space_info->bytes_readonly += len;
4967                 spin_unlock(&cache->lock);
4968                 spin_unlock(&cache->space_info->lock);
4969         }
4970
4971         if (cache)
4972                 btrfs_put_block_group(cache);
4973         return 0;
4974 }
4975
4976 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4977                                struct btrfs_root *root)
4978 {
4979         struct btrfs_fs_info *fs_info = root->fs_info;
4980         struct extent_io_tree *unpin;
4981         u64 start;
4982         u64 end;
4983         int ret;
4984
4985         if (trans->aborted)
4986                 return 0;
4987
4988         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4989                 unpin = &fs_info->freed_extents[1];
4990         else
4991                 unpin = &fs_info->freed_extents[0];
4992
4993         while (1) {
4994                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4995                                             EXTENT_DIRTY);
4996                 if (ret)
4997                         break;
4998
4999                 if (btrfs_test_opt(root, DISCARD))
5000                         ret = btrfs_discard_extent(root, start,
5001                                                    end + 1 - start, NULL);
5002
5003                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5004                 unpin_extent_range(root, start, end);
5005                 cond_resched();
5006         }
5007
5008         return 0;
5009 }
5010
5011 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5012                                 struct btrfs_root *root,
5013                                 u64 bytenr, u64 num_bytes, u64 parent,
5014                                 u64 root_objectid, u64 owner_objectid,
5015                                 u64 owner_offset, int refs_to_drop,
5016                                 struct btrfs_delayed_extent_op *extent_op)
5017 {
5018         struct btrfs_key key;
5019         struct btrfs_path *path;
5020         struct btrfs_fs_info *info = root->fs_info;
5021         struct btrfs_root *extent_root = info->extent_root;
5022         struct extent_buffer *leaf;
5023         struct btrfs_extent_item *ei;
5024         struct btrfs_extent_inline_ref *iref;
5025         int ret;
5026         int is_data;
5027         int extent_slot = 0;
5028         int found_extent = 0;
5029         int num_to_del = 1;
5030         u32 item_size;
5031         u64 refs;
5032
5033         path = btrfs_alloc_path();
5034         if (!path)
5035                 return -ENOMEM;
5036
5037         path->reada = 1;
5038         path->leave_spinning = 1;
5039
5040         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5041         BUG_ON(!is_data && refs_to_drop != 1);
5042
5043         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5044                                     bytenr, num_bytes, parent,
5045                                     root_objectid, owner_objectid,
5046                                     owner_offset);
5047         if (ret == 0) {
5048                 extent_slot = path->slots[0];
5049                 while (extent_slot >= 0) {
5050                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5051                                               extent_slot);
5052                         if (key.objectid != bytenr)
5053                                 break;
5054                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5055                             key.offset == num_bytes) {
5056                                 found_extent = 1;
5057                                 break;
5058                         }
5059                         if (path->slots[0] - extent_slot > 5)
5060                                 break;
5061                         extent_slot--;
5062                 }
5063 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5064                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5065                 if (found_extent && item_size < sizeof(*ei))
5066                         found_extent = 0;
5067 #endif
5068                 if (!found_extent) {
5069                         BUG_ON(iref);
5070                         ret = remove_extent_backref(trans, extent_root, path,
5071                                                     NULL, refs_to_drop,
5072                                                     is_data);
5073                         if (ret)
5074                                 goto abort;
5075                         btrfs_release_path(path);
5076                         path->leave_spinning = 1;
5077
5078                         key.objectid = bytenr;
5079                         key.type = BTRFS_EXTENT_ITEM_KEY;
5080                         key.offset = num_bytes;
5081
5082                         ret = btrfs_search_slot(trans, extent_root,
5083                                                 &key, path, -1, 1);
5084                         if (ret) {
5085                                 printk(KERN_ERR "umm, got %d back from search"
5086                                        ", was looking for %llu\n", ret,
5087                                        (unsigned long long)bytenr);
5088                                 if (ret > 0)
5089                                         btrfs_print_leaf(extent_root,
5090                                                          path->nodes[0]);
5091                         }
5092                         if (ret < 0)
5093                                 goto abort;
5094                         extent_slot = path->slots[0];
5095                 }
5096         } else if (ret == -ENOENT) {
5097                 btrfs_print_leaf(extent_root, path->nodes[0]);
5098                 WARN_ON(1);
5099                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
5100                        "parent %llu root %llu  owner %llu offset %llu\n",
5101                        (unsigned long long)bytenr,
5102                        (unsigned long long)parent,
5103                        (unsigned long long)root_objectid,
5104                        (unsigned long long)owner_objectid,
5105                        (unsigned long long)owner_offset);
5106         } else {
5107                 goto abort;
5108         }
5109
5110         leaf = path->nodes[0];
5111         item_size = btrfs_item_size_nr(leaf, extent_slot);
5112 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5113         if (item_size < sizeof(*ei)) {
5114                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5115                 ret = convert_extent_item_v0(trans, extent_root, path,
5116                                              owner_objectid, 0);
5117                 if (ret < 0)
5118                         goto abort;
5119
5120                 btrfs_release_path(path);
5121                 path->leave_spinning = 1;
5122
5123                 key.objectid = bytenr;
5124                 key.type = BTRFS_EXTENT_ITEM_KEY;
5125                 key.offset = num_bytes;
5126
5127                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5128                                         -1, 1);
5129                 if (ret) {
5130                         printk(KERN_ERR "umm, got %d back from search"
5131                                ", was looking for %llu\n", ret,
5132                                (unsigned long long)bytenr);
5133                         btrfs_print_leaf(extent_root, path->nodes[0]);
5134                 }
5135                 if (ret < 0)
5136                         goto abort;
5137                 extent_slot = path->slots[0];
5138                 leaf = path->nodes[0];
5139                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5140         }
5141 #endif
5142         BUG_ON(item_size < sizeof(*ei));
5143         ei = btrfs_item_ptr(leaf, extent_slot,
5144                             struct btrfs_extent_item);
5145         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5146                 struct btrfs_tree_block_info *bi;
5147                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5148                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5149                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5150         }
5151
5152         refs = btrfs_extent_refs(leaf, ei);
5153         BUG_ON(refs < refs_to_drop);
5154         refs -= refs_to_drop;
5155
5156         if (refs > 0) {
5157                 if (extent_op)
5158                         __run_delayed_extent_op(extent_op, leaf, ei);
5159                 /*
5160                  * In the case of inline back ref, reference count will
5161                  * be updated by remove_extent_backref
5162                  */
5163                 if (iref) {
5164                         BUG_ON(!found_extent);
5165                 } else {
5166                         btrfs_set_extent_refs(leaf, ei, refs);
5167                         btrfs_mark_buffer_dirty(leaf);
5168                 }
5169                 if (found_extent) {
5170                         ret = remove_extent_backref(trans, extent_root, path,
5171                                                     iref, refs_to_drop,
5172                                                     is_data);
5173                         if (ret)
5174                                 goto abort;
5175                 }
5176         } else {
5177                 if (found_extent) {
5178                         BUG_ON(is_data && refs_to_drop !=
5179                                extent_data_ref_count(root, path, iref));
5180                         if (iref) {
5181                                 BUG_ON(path->slots[0] != extent_slot);
5182                         } else {
5183                                 BUG_ON(path->slots[0] != extent_slot + 1);
5184                                 path->slots[0] = extent_slot;
5185                                 num_to_del = 2;
5186                         }
5187                 }
5188
5189                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5190                                       num_to_del);
5191                 if (ret)
5192                         goto abort;
5193                 btrfs_release_path(path);
5194
5195                 if (is_data) {
5196                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5197                         if (ret)
5198                                 goto abort;
5199                 }
5200
5201                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5202                 if (ret)
5203                         goto abort;
5204         }
5205 out:
5206         btrfs_free_path(path);
5207         return ret;
5208
5209 abort:
5210         btrfs_abort_transaction(trans, extent_root, ret);
5211         goto out;
5212 }
5213
5214 /*
5215  * when we free an block, it is possible (and likely) that we free the last
5216  * delayed ref for that extent as well.  This searches the delayed ref tree for
5217  * a given extent, and if there are no other delayed refs to be processed, it
5218  * removes it from the tree.
5219  */
5220 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5221                                       struct btrfs_root *root, u64 bytenr)
5222 {
5223         struct btrfs_delayed_ref_head *head;
5224         struct btrfs_delayed_ref_root *delayed_refs;
5225         struct btrfs_delayed_ref_node *ref;
5226         struct rb_node *node;
5227         int ret = 0;
5228
5229         delayed_refs = &trans->transaction->delayed_refs;
5230         spin_lock(&delayed_refs->lock);
5231         head = btrfs_find_delayed_ref_head(trans, bytenr);
5232         if (!head)
5233                 goto out;
5234
5235         node = rb_prev(&head->node.rb_node);
5236         if (!node)
5237                 goto out;
5238
5239         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5240
5241         /* there are still entries for this ref, we can't drop it */
5242         if (ref->bytenr == bytenr)
5243                 goto out;
5244
5245         if (head->extent_op) {
5246                 if (!head->must_insert_reserved)
5247                         goto out;
5248                 kfree(head->extent_op);
5249                 head->extent_op = NULL;
5250         }
5251
5252         /*
5253          * waiting for the lock here would deadlock.  If someone else has it
5254          * locked they are already in the process of dropping it anyway
5255          */
5256         if (!mutex_trylock(&head->mutex))
5257                 goto out;
5258
5259         /*
5260          * at this point we have a head with no other entries.  Go
5261          * ahead and process it.
5262          */
5263         head->node.in_tree = 0;
5264         rb_erase(&head->node.rb_node, &delayed_refs->root);
5265
5266         delayed_refs->num_entries--;
5267
5268         /*
5269          * we don't take a ref on the node because we're removing it from the
5270          * tree, so we just steal the ref the tree was holding.
5271          */
5272         delayed_refs->num_heads--;
5273         if (list_empty(&head->cluster))
5274                 delayed_refs->num_heads_ready--;
5275
5276         list_del_init(&head->cluster);
5277         spin_unlock(&delayed_refs->lock);
5278
5279         BUG_ON(head->extent_op);
5280         if (head->must_insert_reserved)
5281                 ret = 1;
5282
5283         mutex_unlock(&head->mutex);
5284         btrfs_put_delayed_ref(&head->node);
5285         return ret;
5286 out:
5287         spin_unlock(&delayed_refs->lock);
5288         return 0;
5289 }
5290
5291 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5292                            struct btrfs_root *root,
5293                            struct extent_buffer *buf,
5294                            u64 parent, int last_ref)
5295 {
5296         struct btrfs_block_group_cache *cache = NULL;
5297         int ret;
5298
5299         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5300                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5301                                         buf->start, buf->len,
5302                                         parent, root->root_key.objectid,
5303                                         btrfs_header_level(buf),
5304                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5305                 BUG_ON(ret); /* -ENOMEM */
5306         }
5307
5308         if (!last_ref)
5309                 return;
5310
5311         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5312
5313         if (btrfs_header_generation(buf) == trans->transid) {
5314                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5315                         ret = check_ref_cleanup(trans, root, buf->start);
5316                         if (!ret)
5317                                 goto out;
5318                 }
5319
5320                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5321                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5322                         goto out;
5323                 }
5324
5325                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5326
5327                 btrfs_add_free_space(cache, buf->start, buf->len);
5328                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5329         }
5330 out:
5331         /*
5332          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5333          * anymore.
5334          */
5335         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5336         btrfs_put_block_group(cache);
5337 }
5338
5339 /* Can return -ENOMEM */
5340 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5341                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5342                       u64 owner, u64 offset, int for_cow)
5343 {
5344         int ret;
5345         struct btrfs_fs_info *fs_info = root->fs_info;
5346
5347         /*
5348          * tree log blocks never actually go into the extent allocation
5349          * tree, just update pinning info and exit early.
5350          */
5351         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5352                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5353                 /* unlocks the pinned mutex */
5354                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5355                 ret = 0;
5356         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5357                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5358                                         num_bytes,
5359                                         parent, root_objectid, (int)owner,
5360                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5361         } else {
5362                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5363                                                 num_bytes,
5364                                                 parent, root_objectid, owner,
5365                                                 offset, BTRFS_DROP_DELAYED_REF,
5366                                                 NULL, for_cow);
5367         }
5368         return ret;
5369 }
5370
5371 static u64 stripe_align(struct btrfs_root *root, u64 val)
5372 {
5373         u64 mask = ((u64)root->stripesize - 1);
5374         u64 ret = (val + mask) & ~mask;
5375         return ret;
5376 }
5377
5378 /*
5379  * when we wait for progress in the block group caching, its because
5380  * our allocation attempt failed at least once.  So, we must sleep
5381  * and let some progress happen before we try again.
5382  *
5383  * This function will sleep at least once waiting for new free space to
5384  * show up, and then it will check the block group free space numbers
5385  * for our min num_bytes.  Another option is to have it go ahead
5386  * and look in the rbtree for a free extent of a given size, but this
5387  * is a good start.
5388  */
5389 static noinline int
5390 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5391                                 u64 num_bytes)
5392 {
5393         struct btrfs_caching_control *caching_ctl;
5394         DEFINE_WAIT(wait);
5395
5396         caching_ctl = get_caching_control(cache);
5397         if (!caching_ctl)
5398                 return 0;
5399
5400         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5401                    (cache->free_space_ctl->free_space >= num_bytes));
5402
5403         put_caching_control(caching_ctl);
5404         return 0;
5405 }
5406
5407 static noinline int
5408 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5409 {
5410         struct btrfs_caching_control *caching_ctl;
5411         DEFINE_WAIT(wait);
5412
5413         caching_ctl = get_caching_control(cache);
5414         if (!caching_ctl)
5415                 return 0;
5416
5417         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5418
5419         put_caching_control(caching_ctl);
5420         return 0;
5421 }
5422
5423 static int __get_block_group_index(u64 flags)
5424 {
5425         int index;
5426
5427         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5428                 index = 0;
5429         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5430                 index = 1;
5431         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5432                 index = 2;
5433         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5434                 index = 3;
5435         else
5436                 index = 4;
5437
5438         return index;
5439 }
5440
5441 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5442 {
5443         return __get_block_group_index(cache->flags);
5444 }
5445
5446 enum btrfs_loop_type {
5447         LOOP_CACHING_NOWAIT = 0,
5448         LOOP_CACHING_WAIT = 1,
5449         LOOP_ALLOC_CHUNK = 2,
5450         LOOP_NO_EMPTY_SIZE = 3,
5451 };
5452
5453 /*
5454  * walks the btree of allocated extents and find a hole of a given size.
5455  * The key ins is changed to record the hole:
5456  * ins->objectid == block start
5457  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5458  * ins->offset == number of blocks
5459  * Any available blocks before search_start are skipped.
5460  */
5461 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5462                                      struct btrfs_root *orig_root,
5463                                      u64 num_bytes, u64 empty_size,
5464                                      u64 hint_byte, struct btrfs_key *ins,
5465                                      u64 data)
5466 {
5467         int ret = 0;
5468         struct btrfs_root *root = orig_root->fs_info->extent_root;
5469         struct btrfs_free_cluster *last_ptr = NULL;
5470         struct btrfs_block_group_cache *block_group = NULL;
5471         struct btrfs_block_group_cache *used_block_group;
5472         u64 search_start = 0;
5473         int empty_cluster = 2 * 1024 * 1024;
5474         int allowed_chunk_alloc = 0;
5475         int done_chunk_alloc = 0;
5476         struct btrfs_space_info *space_info;
5477         int loop = 0;
5478         int index = 0;
5479         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5480                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5481         bool found_uncached_bg = false;
5482         bool failed_cluster_refill = false;
5483         bool failed_alloc = false;
5484         bool use_cluster = true;
5485         bool have_caching_bg = false;
5486
5487         WARN_ON(num_bytes < root->sectorsize);
5488         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5489         ins->objectid = 0;
5490         ins->offset = 0;
5491
5492         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5493
5494         space_info = __find_space_info(root->fs_info, data);
5495         if (!space_info) {
5496                 printk(KERN_ERR "No space info for %llu\n", data);
5497                 return -ENOSPC;
5498         }
5499
5500         /*
5501          * If the space info is for both data and metadata it means we have a
5502          * small filesystem and we can't use the clustering stuff.
5503          */
5504         if (btrfs_mixed_space_info(space_info))
5505                 use_cluster = false;
5506
5507         if (orig_root->ref_cows || empty_size)
5508                 allowed_chunk_alloc = 1;
5509
5510         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5511                 last_ptr = &root->fs_info->meta_alloc_cluster;
5512                 if (!btrfs_test_opt(root, SSD))
5513                         empty_cluster = 64 * 1024;
5514         }
5515
5516         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5517             btrfs_test_opt(root, SSD)) {
5518                 last_ptr = &root->fs_info->data_alloc_cluster;
5519         }
5520
5521         if (last_ptr) {
5522                 spin_lock(&last_ptr->lock);
5523                 if (last_ptr->block_group)
5524                         hint_byte = last_ptr->window_start;
5525                 spin_unlock(&last_ptr->lock);
5526         }
5527
5528         search_start = max(search_start, first_logical_byte(root, 0));
5529         search_start = max(search_start, hint_byte);
5530
5531         if (!last_ptr)
5532                 empty_cluster = 0;
5533
5534         if (search_start == hint_byte) {
5535                 block_group = btrfs_lookup_block_group(root->fs_info,
5536                                                        search_start);
5537                 used_block_group = block_group;
5538                 /*
5539                  * we don't want to use the block group if it doesn't match our
5540                  * allocation bits, or if its not cached.
5541                  *
5542                  * However if we are re-searching with an ideal block group
5543                  * picked out then we don't care that the block group is cached.
5544                  */
5545                 if (block_group && block_group_bits(block_group, data) &&
5546                     block_group->cached != BTRFS_CACHE_NO) {
5547                         down_read(&space_info->groups_sem);
5548                         if (list_empty(&block_group->list) ||
5549                             block_group->ro) {
5550                                 /*
5551                                  * someone is removing this block group,
5552                                  * we can't jump into the have_block_group
5553                                  * target because our list pointers are not
5554                                  * valid
5555                                  */
5556                                 btrfs_put_block_group(block_group);
5557                                 up_read(&space_info->groups_sem);
5558                         } else {
5559                                 index = get_block_group_index(block_group);
5560                                 goto have_block_group;
5561                         }
5562                 } else if (block_group) {
5563                         btrfs_put_block_group(block_group);
5564                 }
5565         }
5566 search:
5567         have_caching_bg = false;
5568         down_read(&space_info->groups_sem);
5569         list_for_each_entry(block_group, &space_info->block_groups[index],
5570                             list) {
5571                 u64 offset;
5572                 int cached;
5573
5574                 used_block_group = block_group;
5575                 btrfs_get_block_group(block_group);
5576                 search_start = block_group->key.objectid;
5577
5578                 /*
5579                  * this can happen if we end up cycling through all the
5580                  * raid types, but we want to make sure we only allocate
5581                  * for the proper type.
5582                  */
5583                 if (!block_group_bits(block_group, data)) {
5584                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5585                                 BTRFS_BLOCK_GROUP_RAID1 |
5586                                 BTRFS_BLOCK_GROUP_RAID10;
5587
5588                         /*
5589                          * if they asked for extra copies and this block group
5590                          * doesn't provide them, bail.  This does allow us to
5591                          * fill raid0 from raid1.
5592                          */
5593                         if ((data & extra) && !(block_group->flags & extra))
5594                                 goto loop;
5595                 }
5596
5597 have_block_group:
5598                 cached = block_group_cache_done(block_group);
5599                 if (unlikely(!cached)) {
5600                         found_uncached_bg = true;
5601                         ret = cache_block_group(block_group, trans,
5602                                                 orig_root, 0);
5603                         BUG_ON(ret < 0);
5604                         ret = 0;
5605                 }
5606
5607                 if (unlikely(block_group->ro))
5608                         goto loop;
5609
5610                 /*
5611                  * Ok we want to try and use the cluster allocator, so
5612                  * lets look there
5613                  */
5614                 if (last_ptr) {
5615                         /*
5616                          * the refill lock keeps out other
5617                          * people trying to start a new cluster
5618                          */
5619                         spin_lock(&last_ptr->refill_lock);
5620                         used_block_group = last_ptr->block_group;
5621                         if (used_block_group != block_group &&
5622                             (!used_block_group ||
5623                              used_block_group->ro ||
5624                              !block_group_bits(used_block_group, data))) {
5625                                 used_block_group = block_group;
5626                                 goto refill_cluster;
5627                         }
5628
5629                         if (used_block_group != block_group)
5630                                 btrfs_get_block_group(used_block_group);
5631
5632                         offset = btrfs_alloc_from_cluster(used_block_group,
5633                           last_ptr, num_bytes, used_block_group->key.objectid);
5634                         if (offset) {
5635                                 /* we have a block, we're done */
5636                                 spin_unlock(&last_ptr->refill_lock);
5637                                 trace_btrfs_reserve_extent_cluster(root,
5638                                         block_group, search_start, num_bytes);
5639                                 goto checks;
5640                         }
5641
5642                         WARN_ON(last_ptr->block_group != used_block_group);
5643                         if (used_block_group != block_group) {
5644                                 btrfs_put_block_group(used_block_group);
5645                                 used_block_group = block_group;
5646                         }
5647 refill_cluster:
5648                         BUG_ON(used_block_group != block_group);
5649                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5650                          * set up a new clusters, so lets just skip it
5651                          * and let the allocator find whatever block
5652                          * it can find.  If we reach this point, we
5653                          * will have tried the cluster allocator
5654                          * plenty of times and not have found
5655                          * anything, so we are likely way too
5656                          * fragmented for the clustering stuff to find
5657                          * anything.
5658                          *
5659                          * However, if the cluster is taken from the
5660                          * current block group, release the cluster
5661                          * first, so that we stand a better chance of
5662                          * succeeding in the unclustered
5663                          * allocation.  */
5664                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5665                             last_ptr->block_group != block_group) {
5666                                 spin_unlock(&last_ptr->refill_lock);
5667                                 goto unclustered_alloc;
5668                         }
5669
5670                         /*
5671                          * this cluster didn't work out, free it and
5672                          * start over
5673                          */
5674                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5675
5676                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5677                                 spin_unlock(&last_ptr->refill_lock);
5678                                 goto unclustered_alloc;
5679                         }
5680
5681                         /* allocate a cluster in this block group */
5682                         ret = btrfs_find_space_cluster(trans, root,
5683                                                block_group, last_ptr,
5684                                                search_start, num_bytes,
5685                                                empty_cluster + empty_size);
5686                         if (ret == 0) {
5687                                 /*
5688                                  * now pull our allocation out of this
5689                                  * cluster
5690                                  */
5691                                 offset = btrfs_alloc_from_cluster(block_group,
5692                                                   last_ptr, num_bytes,
5693                                                   search_start);
5694                                 if (offset) {
5695                                         /* we found one, proceed */
5696                                         spin_unlock(&last_ptr->refill_lock);
5697                                         trace_btrfs_reserve_extent_cluster(root,
5698                                                 block_group, search_start,
5699                                                 num_bytes);
5700                                         goto checks;
5701                                 }
5702                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5703                                    && !failed_cluster_refill) {
5704                                 spin_unlock(&last_ptr->refill_lock);
5705
5706                                 failed_cluster_refill = true;
5707                                 wait_block_group_cache_progress(block_group,
5708                                        num_bytes + empty_cluster + empty_size);
5709                                 goto have_block_group;
5710                         }
5711
5712                         /*
5713                          * at this point we either didn't find a cluster
5714                          * or we weren't able to allocate a block from our
5715                          * cluster.  Free the cluster we've been trying
5716                          * to use, and go to the next block group
5717                          */
5718                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5719                         spin_unlock(&last_ptr->refill_lock);
5720                         goto loop;
5721                 }
5722
5723 unclustered_alloc:
5724                 spin_lock(&block_group->free_space_ctl->tree_lock);
5725                 if (cached &&
5726                     block_group->free_space_ctl->free_space <
5727                     num_bytes + empty_cluster + empty_size) {
5728                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5729                         goto loop;
5730                 }
5731                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5732
5733                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5734                                                     num_bytes, empty_size);
5735                 /*
5736                  * If we didn't find a chunk, and we haven't failed on this
5737                  * block group before, and this block group is in the middle of
5738                  * caching and we are ok with waiting, then go ahead and wait
5739                  * for progress to be made, and set failed_alloc to true.
5740                  *
5741                  * If failed_alloc is true then we've already waited on this
5742                  * block group once and should move on to the next block group.
5743                  */
5744                 if (!offset && !failed_alloc && !cached &&
5745                     loop > LOOP_CACHING_NOWAIT) {
5746                         wait_block_group_cache_progress(block_group,
5747                                                 num_bytes + empty_size);
5748                         failed_alloc = true;
5749                         goto have_block_group;
5750                 } else if (!offset) {
5751                         if (!cached)
5752                                 have_caching_bg = true;
5753                         goto loop;
5754                 }
5755 checks:
5756                 search_start = stripe_align(root, offset);
5757
5758                 /* move on to the next group */
5759                 if (search_start + num_bytes >
5760                     used_block_group->key.objectid + used_block_group->key.offset) {
5761                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5762                         goto loop;
5763                 }
5764
5765                 if (offset < search_start)
5766                         btrfs_add_free_space(used_block_group, offset,
5767                                              search_start - offset);
5768                 BUG_ON(offset > search_start);
5769
5770                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5771                                                   alloc_type);
5772                 if (ret == -EAGAIN) {
5773                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5774                         goto loop;
5775                 }
5776
5777                 /* we are all good, lets return */
5778                 ins->objectid = search_start;
5779                 ins->offset = num_bytes;
5780
5781                 trace_btrfs_reserve_extent(orig_root, block_group,
5782                                            search_start, num_bytes);
5783                 if (offset < search_start)
5784                         btrfs_add_free_space(used_block_group, offset,
5785                                              search_start - offset);
5786                 BUG_ON(offset > search_start);
5787                 if (used_block_group != block_group)
5788                         btrfs_put_block_group(used_block_group);
5789                 btrfs_put_block_group(block_group);
5790                 break;
5791 loop:
5792                 failed_cluster_refill = false;
5793                 failed_alloc = false;
5794                 BUG_ON(index != get_block_group_index(block_group));
5795                 if (used_block_group != block_group)
5796                         btrfs_put_block_group(used_block_group);
5797                 btrfs_put_block_group(block_group);
5798         }
5799         up_read(&space_info->groups_sem);
5800
5801         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5802                 goto search;
5803
5804         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5805                 goto search;
5806
5807         /*
5808          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5809          *                      caching kthreads as we move along
5810          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5811          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5812          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5813          *                      again
5814          */
5815         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5816                 index = 0;
5817                 loop++;
5818                 if (loop == LOOP_ALLOC_CHUNK) {
5819                        if (allowed_chunk_alloc) {
5820                                 ret = do_chunk_alloc(trans, root, num_bytes +
5821                                                      2 * 1024 * 1024, data,
5822                                                      CHUNK_ALLOC_LIMITED);
5823                                 /*
5824                                  * Do not bail out on ENOSPC since we
5825                                  * can do more things.
5826                                  */
5827                                 if (ret < 0 && ret != -ENOSPC) {
5828                                         btrfs_abort_transaction(trans,
5829                                                                 root, ret);
5830                                         goto out;
5831                                 }
5832                                 allowed_chunk_alloc = 0;
5833                                 if (ret == 1)
5834                                         done_chunk_alloc = 1;
5835                         } else if (!done_chunk_alloc &&
5836                                    space_info->force_alloc ==
5837                                    CHUNK_ALLOC_NO_FORCE) {
5838                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5839                         }
5840
5841                        /*
5842                         * We didn't allocate a chunk, go ahead and drop the
5843                         * empty size and loop again.
5844                         */
5845                        if (!done_chunk_alloc)
5846                                loop = LOOP_NO_EMPTY_SIZE;
5847                 }
5848
5849                 if (loop == LOOP_NO_EMPTY_SIZE) {
5850                         empty_size = 0;
5851                         empty_cluster = 0;
5852                 }
5853
5854                 goto search;
5855         } else if (!ins->objectid) {
5856                 ret = -ENOSPC;
5857         } else if (ins->objectid) {
5858                 ret = 0;
5859         }
5860 out:
5861
5862         return ret;
5863 }
5864
5865 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5866                             int dump_block_groups)
5867 {
5868         struct btrfs_block_group_cache *cache;
5869         int index = 0;
5870
5871         spin_lock(&info->lock);
5872         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5873                (unsigned long long)info->flags,
5874                (unsigned long long)(info->total_bytes - info->bytes_used -
5875                                     info->bytes_pinned - info->bytes_reserved -
5876                                     info->bytes_readonly),
5877                (info->full) ? "" : "not ");
5878         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5879                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5880                (unsigned long long)info->total_bytes,
5881                (unsigned long long)info->bytes_used,
5882                (unsigned long long)info->bytes_pinned,
5883                (unsigned long long)info->bytes_reserved,
5884                (unsigned long long)info->bytes_may_use,
5885                (unsigned long long)info->bytes_readonly);
5886         spin_unlock(&info->lock);
5887
5888         if (!dump_block_groups)
5889                 return;
5890
5891         down_read(&info->groups_sem);
5892 again:
5893         list_for_each_entry(cache, &info->block_groups[index], list) {
5894                 spin_lock(&cache->lock);
5895                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
5896                        (unsigned long long)cache->key.objectid,
5897                        (unsigned long long)cache->key.offset,
5898                        (unsigned long long)btrfs_block_group_used(&cache->item),
5899                        (unsigned long long)cache->pinned,
5900                        (unsigned long long)cache->reserved,
5901                        cache->ro ? "[readonly]" : "");
5902                 btrfs_dump_free_space(cache, bytes);
5903                 spin_unlock(&cache->lock);
5904         }
5905         if (++index < BTRFS_NR_RAID_TYPES)
5906                 goto again;
5907         up_read(&info->groups_sem);
5908 }
5909
5910 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5911                          struct btrfs_root *root,
5912                          u64 num_bytes, u64 min_alloc_size,
5913                          u64 empty_size, u64 hint_byte,
5914                          struct btrfs_key *ins, u64 data)
5915 {
5916         bool final_tried = false;
5917         int ret;
5918
5919         data = btrfs_get_alloc_profile(root, data);
5920 again:
5921         /*
5922          * the only place that sets empty_size is btrfs_realloc_node, which
5923          * is not called recursively on allocations
5924          */
5925         if (empty_size || root->ref_cows) {
5926                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5927                                      num_bytes + 2 * 1024 * 1024, data,
5928                                      CHUNK_ALLOC_NO_FORCE);
5929                 if (ret < 0 && ret != -ENOSPC) {
5930                         btrfs_abort_transaction(trans, root, ret);
5931                         return ret;
5932                 }
5933         }
5934
5935         WARN_ON(num_bytes < root->sectorsize);
5936         ret = find_free_extent(trans, root, num_bytes, empty_size,
5937                                hint_byte, ins, data);
5938
5939         if (ret == -ENOSPC) {
5940                 if (!final_tried) {
5941                         num_bytes = num_bytes >> 1;
5942                         num_bytes = num_bytes & ~(root->sectorsize - 1);
5943                         num_bytes = max(num_bytes, min_alloc_size);
5944                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5945                                        num_bytes, data, CHUNK_ALLOC_FORCE);
5946                         if (ret < 0 && ret != -ENOSPC) {
5947                                 btrfs_abort_transaction(trans, root, ret);
5948                                 return ret;
5949                         }
5950                         if (num_bytes == min_alloc_size)
5951                                 final_tried = true;
5952                         goto again;
5953                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
5954                         struct btrfs_space_info *sinfo;
5955
5956                         sinfo = __find_space_info(root->fs_info, data);
5957                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
5958                                "wanted %llu\n", (unsigned long long)data,
5959                                (unsigned long long)num_bytes);
5960                         if (sinfo)
5961                                 dump_space_info(sinfo, num_bytes, 1);
5962                 }
5963         }
5964
5965         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5966
5967         return ret;
5968 }
5969
5970 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5971                                         u64 start, u64 len, int pin)
5972 {
5973         struct btrfs_block_group_cache *cache;
5974         int ret = 0;
5975
5976         cache = btrfs_lookup_block_group(root->fs_info, start);
5977         if (!cache) {
5978                 printk(KERN_ERR "Unable to find block group for %llu\n",
5979                        (unsigned long long)start);
5980                 return -ENOSPC;
5981         }
5982
5983         if (btrfs_test_opt(root, DISCARD))
5984                 ret = btrfs_discard_extent(root, start, len, NULL);
5985
5986         if (pin)
5987                 pin_down_extent(root, cache, start, len, 1);
5988         else {
5989                 btrfs_add_free_space(cache, start, len);
5990                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5991         }
5992         btrfs_put_block_group(cache);
5993
5994         trace_btrfs_reserved_extent_free(root, start, len);
5995
5996         return ret;
5997 }
5998
5999 int btrfs_free_reserved_extent(struct btrfs_root *root,
6000                                         u64 start, u64 len)
6001 {
6002         return __btrfs_free_reserved_extent(root, start, len, 0);
6003 }
6004
6005 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6006                                        u64 start, u64 len)
6007 {
6008         return __btrfs_free_reserved_extent(root, start, len, 1);
6009 }
6010
6011 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6012                                       struct btrfs_root *root,
6013                                       u64 parent, u64 root_objectid,
6014                                       u64 flags, u64 owner, u64 offset,
6015                                       struct btrfs_key *ins, int ref_mod)
6016 {
6017         int ret;
6018         struct btrfs_fs_info *fs_info = root->fs_info;
6019         struct btrfs_extent_item *extent_item;
6020         struct btrfs_extent_inline_ref *iref;
6021         struct btrfs_path *path;
6022         struct extent_buffer *leaf;
6023         int type;
6024         u32 size;
6025
6026         if (parent > 0)
6027                 type = BTRFS_SHARED_DATA_REF_KEY;
6028         else
6029                 type = BTRFS_EXTENT_DATA_REF_KEY;
6030
6031         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6032
6033         path = btrfs_alloc_path();
6034         if (!path)
6035                 return -ENOMEM;
6036
6037         path->leave_spinning = 1;
6038         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6039                                       ins, size);
6040         if (ret) {
6041                 btrfs_free_path(path);
6042                 return ret;
6043         }
6044
6045         leaf = path->nodes[0];
6046         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6047                                      struct btrfs_extent_item);
6048         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6049         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6050         btrfs_set_extent_flags(leaf, extent_item,
6051                                flags | BTRFS_EXTENT_FLAG_DATA);
6052
6053         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6054         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6055         if (parent > 0) {
6056                 struct btrfs_shared_data_ref *ref;
6057                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6058                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6059                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6060         } else {
6061                 struct btrfs_extent_data_ref *ref;
6062                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6063                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6064                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6065                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6066                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6067         }
6068
6069         btrfs_mark_buffer_dirty(path->nodes[0]);
6070         btrfs_free_path(path);
6071
6072         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6073         if (ret) { /* -ENOENT, logic error */
6074                 printk(KERN_ERR "btrfs update block group failed for %llu "
6075                        "%llu\n", (unsigned long long)ins->objectid,
6076                        (unsigned long long)ins->offset);
6077                 BUG();
6078         }
6079         return ret;
6080 }
6081
6082 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6083                                      struct btrfs_root *root,
6084                                      u64 parent, u64 root_objectid,
6085                                      u64 flags, struct btrfs_disk_key *key,
6086                                      int level, struct btrfs_key *ins)
6087 {
6088         int ret;
6089         struct btrfs_fs_info *fs_info = root->fs_info;
6090         struct btrfs_extent_item *extent_item;
6091         struct btrfs_tree_block_info *block_info;
6092         struct btrfs_extent_inline_ref *iref;
6093         struct btrfs_path *path;
6094         struct extent_buffer *leaf;
6095         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
6096
6097         path = btrfs_alloc_path();
6098         if (!path)
6099                 return -ENOMEM;
6100
6101         path->leave_spinning = 1;
6102         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6103                                       ins, size);
6104         if (ret) {
6105                 btrfs_free_path(path);
6106                 return ret;
6107         }
6108
6109         leaf = path->nodes[0];
6110         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6111                                      struct btrfs_extent_item);
6112         btrfs_set_extent_refs(leaf, extent_item, 1);
6113         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6114         btrfs_set_extent_flags(leaf, extent_item,
6115                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6116         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6117
6118         btrfs_set_tree_block_key(leaf, block_info, key);
6119         btrfs_set_tree_block_level(leaf, block_info, level);
6120
6121         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6122         if (parent > 0) {
6123                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6124                 btrfs_set_extent_inline_ref_type(leaf, iref,
6125                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6126                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6127         } else {
6128                 btrfs_set_extent_inline_ref_type(leaf, iref,
6129                                                  BTRFS_TREE_BLOCK_REF_KEY);
6130                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6131         }
6132
6133         btrfs_mark_buffer_dirty(leaf);
6134         btrfs_free_path(path);
6135
6136         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6137         if (ret) { /* -ENOENT, logic error */
6138                 printk(KERN_ERR "btrfs update block group failed for %llu "
6139                        "%llu\n", (unsigned long long)ins->objectid,
6140                        (unsigned long long)ins->offset);
6141                 BUG();
6142         }
6143         return ret;
6144 }
6145
6146 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6147                                      struct btrfs_root *root,
6148                                      u64 root_objectid, u64 owner,
6149                                      u64 offset, struct btrfs_key *ins)
6150 {
6151         int ret;
6152
6153         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6154
6155         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6156                                          ins->offset, 0,
6157                                          root_objectid, owner, offset,
6158                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6159         return ret;
6160 }
6161
6162 /*
6163  * this is used by the tree logging recovery code.  It records that
6164  * an extent has been allocated and makes sure to clear the free
6165  * space cache bits as well
6166  */
6167 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6168                                    struct btrfs_root *root,
6169                                    u64 root_objectid, u64 owner, u64 offset,
6170                                    struct btrfs_key *ins)
6171 {
6172         int ret;
6173         struct btrfs_block_group_cache *block_group;
6174         struct btrfs_caching_control *caching_ctl;
6175         u64 start = ins->objectid;
6176         u64 num_bytes = ins->offset;
6177
6178         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6179         cache_block_group(block_group, trans, NULL, 0);
6180         caching_ctl = get_caching_control(block_group);
6181
6182         if (!caching_ctl) {
6183                 BUG_ON(!block_group_cache_done(block_group));
6184                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6185                 BUG_ON(ret); /* -ENOMEM */
6186         } else {
6187                 mutex_lock(&caching_ctl->mutex);
6188
6189                 if (start >= caching_ctl->progress) {
6190                         ret = add_excluded_extent(root, start, num_bytes);
6191                         BUG_ON(ret); /* -ENOMEM */
6192                 } else if (start + num_bytes <= caching_ctl->progress) {
6193                         ret = btrfs_remove_free_space(block_group,
6194                                                       start, num_bytes);
6195                         BUG_ON(ret); /* -ENOMEM */
6196                 } else {
6197                         num_bytes = caching_ctl->progress - start;
6198                         ret = btrfs_remove_free_space(block_group,
6199                                                       start, num_bytes);
6200                         BUG_ON(ret); /* -ENOMEM */
6201
6202                         start = caching_ctl->progress;
6203                         num_bytes = ins->objectid + ins->offset -
6204                                     caching_ctl->progress;
6205                         ret = add_excluded_extent(root, start, num_bytes);
6206                         BUG_ON(ret); /* -ENOMEM */
6207                 }
6208
6209                 mutex_unlock(&caching_ctl->mutex);
6210                 put_caching_control(caching_ctl);
6211         }
6212
6213         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6214                                           RESERVE_ALLOC_NO_ACCOUNT);
6215         BUG_ON(ret); /* logic error */
6216         btrfs_put_block_group(block_group);
6217         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6218                                          0, owner, offset, ins, 1);
6219         return ret;
6220 }
6221
6222 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6223                                             struct btrfs_root *root,
6224                                             u64 bytenr, u32 blocksize,
6225                                             int level)
6226 {
6227         struct extent_buffer *buf;
6228
6229         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6230         if (!buf)
6231                 return ERR_PTR(-ENOMEM);
6232         btrfs_set_header_generation(buf, trans->transid);
6233         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6234         btrfs_tree_lock(buf);
6235         clean_tree_block(trans, root, buf);
6236         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6237
6238         btrfs_set_lock_blocking(buf);
6239         btrfs_set_buffer_uptodate(buf);
6240
6241         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6242                 /*
6243                  * we allow two log transactions at a time, use different
6244                  * EXENT bit to differentiate dirty pages.
6245                  */
6246                 if (root->log_transid % 2 == 0)
6247                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6248                                         buf->start + buf->len - 1, GFP_NOFS);
6249                 else
6250                         set_extent_new(&root->dirty_log_pages, buf->start,
6251                                         buf->start + buf->len - 1, GFP_NOFS);
6252         } else {
6253                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6254                          buf->start + buf->len - 1, GFP_NOFS);
6255         }
6256         trans->blocks_used++;
6257         /* this returns a buffer locked for blocking */
6258         return buf;
6259 }
6260
6261 static struct btrfs_block_rsv *
6262 use_block_rsv(struct btrfs_trans_handle *trans,
6263               struct btrfs_root *root, u32 blocksize)
6264 {
6265         struct btrfs_block_rsv *block_rsv;
6266         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6267         int ret;
6268
6269         block_rsv = get_block_rsv(trans, root);
6270
6271         if (block_rsv->size == 0) {
6272                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6273                 /*
6274                  * If we couldn't reserve metadata bytes try and use some from
6275                  * the global reserve.
6276                  */
6277                 if (ret && block_rsv != global_rsv) {
6278                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6279                         if (!ret)
6280                                 return global_rsv;
6281                         return ERR_PTR(ret);
6282                 } else if (ret) {
6283                         return ERR_PTR(ret);
6284                 }
6285                 return block_rsv;
6286         }
6287
6288         ret = block_rsv_use_bytes(block_rsv, blocksize);
6289         if (!ret)
6290                 return block_rsv;
6291         if (ret) {
6292                 static DEFINE_RATELIMIT_STATE(_rs,
6293                                 DEFAULT_RATELIMIT_INTERVAL,
6294                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6295                 if (__ratelimit(&_rs)) {
6296                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6297                         WARN_ON(1);
6298                 }
6299                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6300                 if (!ret) {
6301                         return block_rsv;
6302                 } else if (ret && block_rsv != global_rsv) {
6303                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6304                         if (!ret)
6305                                 return global_rsv;
6306                 }
6307         }
6308
6309         return ERR_PTR(-ENOSPC);
6310 }
6311
6312 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6313                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6314 {
6315         block_rsv_add_bytes(block_rsv, blocksize, 0);
6316         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6317 }
6318
6319 /*
6320  * finds a free extent and does all the dirty work required for allocation
6321  * returns the key for the extent through ins, and a tree buffer for
6322  * the first block of the extent through buf.
6323  *
6324  * returns the tree buffer or NULL.
6325  */
6326 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6327                                         struct btrfs_root *root, u32 blocksize,
6328                                         u64 parent, u64 root_objectid,
6329                                         struct btrfs_disk_key *key, int level,
6330                                         u64 hint, u64 empty_size)
6331 {
6332         struct btrfs_key ins;
6333         struct btrfs_block_rsv *block_rsv;
6334         struct extent_buffer *buf;
6335         u64 flags = 0;
6336         int ret;
6337
6338
6339         block_rsv = use_block_rsv(trans, root, blocksize);
6340         if (IS_ERR(block_rsv))
6341                 return ERR_CAST(block_rsv);
6342
6343         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6344                                    empty_size, hint, &ins, 0);
6345         if (ret) {
6346                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6347                 return ERR_PTR(ret);
6348         }
6349
6350         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6351                                     blocksize, level);
6352         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6353
6354         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6355                 if (parent == 0)
6356                         parent = ins.objectid;
6357                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6358         } else
6359                 BUG_ON(parent > 0);
6360
6361         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6362                 struct btrfs_delayed_extent_op *extent_op;
6363                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6364                 BUG_ON(!extent_op); /* -ENOMEM */
6365                 if (key)
6366                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6367                 else
6368                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6369                 extent_op->flags_to_set = flags;
6370                 extent_op->update_key = 1;
6371                 extent_op->update_flags = 1;
6372                 extent_op->is_data = 0;
6373
6374                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6375                                         ins.objectid,
6376                                         ins.offset, parent, root_objectid,
6377                                         level, BTRFS_ADD_DELAYED_EXTENT,
6378                                         extent_op, 0);
6379                 BUG_ON(ret); /* -ENOMEM */
6380         }
6381         return buf;
6382 }
6383
6384 struct walk_control {
6385         u64 refs[BTRFS_MAX_LEVEL];
6386         u64 flags[BTRFS_MAX_LEVEL];
6387         struct btrfs_key update_progress;
6388         int stage;
6389         int level;
6390         int shared_level;
6391         int update_ref;
6392         int keep_locks;
6393         int reada_slot;
6394         int reada_count;
6395         int for_reloc;
6396 };
6397
6398 #define DROP_REFERENCE  1
6399 #define UPDATE_BACKREF  2
6400
6401 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6402                                      struct btrfs_root *root,
6403                                      struct walk_control *wc,
6404                                      struct btrfs_path *path)
6405 {
6406         u64 bytenr;
6407         u64 generation;
6408         u64 refs;
6409         u64 flags;
6410         u32 nritems;
6411         u32 blocksize;
6412         struct btrfs_key key;
6413         struct extent_buffer *eb;
6414         int ret;
6415         int slot;
6416         int nread = 0;
6417
6418         if (path->slots[wc->level] < wc->reada_slot) {
6419                 wc->reada_count = wc->reada_count * 2 / 3;
6420                 wc->reada_count = max(wc->reada_count, 2);
6421         } else {
6422                 wc->reada_count = wc->reada_count * 3 / 2;
6423                 wc->reada_count = min_t(int, wc->reada_count,
6424                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6425         }
6426
6427         eb = path->nodes[wc->level];
6428         nritems = btrfs_header_nritems(eb);
6429         blocksize = btrfs_level_size(root, wc->level - 1);
6430
6431         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6432                 if (nread >= wc->reada_count)
6433                         break;
6434
6435                 cond_resched();
6436                 bytenr = btrfs_node_blockptr(eb, slot);
6437                 generation = btrfs_node_ptr_generation(eb, slot);
6438
6439                 if (slot == path->slots[wc->level])
6440                         goto reada;
6441
6442                 if (wc->stage == UPDATE_BACKREF &&
6443                     generation <= root->root_key.offset)
6444                         continue;
6445
6446                 /* We don't lock the tree block, it's OK to be racy here */
6447                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6448                                                &refs, &flags);
6449                 /* We don't care about errors in readahead. */
6450                 if (ret < 0)
6451                         continue;
6452                 BUG_ON(refs == 0);
6453
6454                 if (wc->stage == DROP_REFERENCE) {
6455                         if (refs == 1)
6456                                 goto reada;
6457
6458                         if (wc->level == 1 &&
6459                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6460                                 continue;
6461                         if (!wc->update_ref ||
6462                             generation <= root->root_key.offset)
6463                                 continue;
6464                         btrfs_node_key_to_cpu(eb, &key, slot);
6465                         ret = btrfs_comp_cpu_keys(&key,
6466                                                   &wc->update_progress);
6467                         if (ret < 0)
6468                                 continue;
6469                 } else {
6470                         if (wc->level == 1 &&
6471                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6472                                 continue;
6473                 }
6474 reada:
6475                 ret = readahead_tree_block(root, bytenr, blocksize,
6476                                            generation);
6477                 if (ret)
6478                         break;
6479                 nread++;
6480         }
6481         wc->reada_slot = slot;
6482 }
6483
6484 /*
6485  * hepler to process tree block while walking down the tree.
6486  *
6487  * when wc->stage == UPDATE_BACKREF, this function updates
6488  * back refs for pointers in the block.
6489  *
6490  * NOTE: return value 1 means we should stop walking down.
6491  */
6492 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6493                                    struct btrfs_root *root,
6494                                    struct btrfs_path *path,
6495                                    struct walk_control *wc, int lookup_info)
6496 {
6497         int level = wc->level;
6498         struct extent_buffer *eb = path->nodes[level];
6499         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6500         int ret;
6501
6502         if (wc->stage == UPDATE_BACKREF &&
6503             btrfs_header_owner(eb) != root->root_key.objectid)
6504                 return 1;
6505
6506         /*
6507          * when reference count of tree block is 1, it won't increase
6508          * again. once full backref flag is set, we never clear it.
6509          */
6510         if (lookup_info &&
6511             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6512              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6513                 BUG_ON(!path->locks[level]);
6514                 ret = btrfs_lookup_extent_info(trans, root,
6515                                                eb->start, eb->len,
6516                                                &wc->refs[level],
6517                                                &wc->flags[level]);
6518                 BUG_ON(ret == -ENOMEM);
6519                 if (ret)
6520                         return ret;
6521                 BUG_ON(wc->refs[level] == 0);
6522         }
6523
6524         if (wc->stage == DROP_REFERENCE) {
6525                 if (wc->refs[level] > 1)
6526                         return 1;
6527
6528                 if (path->locks[level] && !wc->keep_locks) {
6529                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6530                         path->locks[level] = 0;
6531                 }
6532                 return 0;
6533         }
6534
6535         /* wc->stage == UPDATE_BACKREF */
6536         if (!(wc->flags[level] & flag)) {
6537                 BUG_ON(!path->locks[level]);
6538                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6539                 BUG_ON(ret); /* -ENOMEM */
6540                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6541                 BUG_ON(ret); /* -ENOMEM */
6542                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6543                                                   eb->len, flag, 0);
6544                 BUG_ON(ret); /* -ENOMEM */
6545                 wc->flags[level] |= flag;
6546         }
6547
6548         /*
6549          * the block is shared by multiple trees, so it's not good to
6550          * keep the tree lock
6551          */
6552         if (path->locks[level] && level > 0) {
6553                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6554                 path->locks[level] = 0;
6555         }
6556         return 0;
6557 }
6558
6559 /*
6560  * hepler to process tree block pointer.
6561  *
6562  * when wc->stage == DROP_REFERENCE, this function checks
6563  * reference count of the block pointed to. if the block
6564  * is shared and we need update back refs for the subtree
6565  * rooted at the block, this function changes wc->stage to
6566  * UPDATE_BACKREF. if the block is shared and there is no
6567  * need to update back, this function drops the reference
6568  * to the block.
6569  *
6570  * NOTE: return value 1 means we should stop walking down.
6571  */
6572 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6573                                  struct btrfs_root *root,
6574                                  struct btrfs_path *path,
6575                                  struct walk_control *wc, int *lookup_info)
6576 {
6577         u64 bytenr;
6578         u64 generation;
6579         u64 parent;
6580         u32 blocksize;
6581         struct btrfs_key key;
6582         struct extent_buffer *next;
6583         int level = wc->level;
6584         int reada = 0;
6585         int ret = 0;
6586
6587         generation = btrfs_node_ptr_generation(path->nodes[level],
6588                                                path->slots[level]);
6589         /*
6590          * if the lower level block was created before the snapshot
6591          * was created, we know there is no need to update back refs
6592          * for the subtree
6593          */
6594         if (wc->stage == UPDATE_BACKREF &&
6595             generation <= root->root_key.offset) {
6596                 *lookup_info = 1;
6597                 return 1;
6598         }
6599
6600         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6601         blocksize = btrfs_level_size(root, level - 1);
6602
6603         next = btrfs_find_tree_block(root, bytenr, blocksize);
6604         if (!next) {
6605                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6606                 if (!next)
6607                         return -ENOMEM;
6608                 reada = 1;
6609         }
6610         btrfs_tree_lock(next);
6611         btrfs_set_lock_blocking(next);
6612
6613         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6614                                        &wc->refs[level - 1],
6615                                        &wc->flags[level - 1]);
6616         if (ret < 0) {
6617                 btrfs_tree_unlock(next);
6618                 return ret;
6619         }
6620
6621         BUG_ON(wc->refs[level - 1] == 0);
6622         *lookup_info = 0;
6623
6624         if (wc->stage == DROP_REFERENCE) {
6625                 if (wc->refs[level - 1] > 1) {
6626                         if (level == 1 &&
6627                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6628                                 goto skip;
6629
6630                         if (!wc->update_ref ||
6631                             generation <= root->root_key.offset)
6632                                 goto skip;
6633
6634                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6635                                               path->slots[level]);
6636                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6637                         if (ret < 0)
6638                                 goto skip;
6639
6640                         wc->stage = UPDATE_BACKREF;
6641                         wc->shared_level = level - 1;
6642                 }
6643         } else {
6644                 if (level == 1 &&
6645                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6646                         goto skip;
6647         }
6648
6649         if (!btrfs_buffer_uptodate(next, generation, 0)) {
6650                 btrfs_tree_unlock(next);
6651                 free_extent_buffer(next);
6652                 next = NULL;
6653                 *lookup_info = 1;
6654         }
6655
6656         if (!next) {
6657                 if (reada && level == 1)
6658                         reada_walk_down(trans, root, wc, path);
6659                 next = read_tree_block(root, bytenr, blocksize, generation);
6660                 if (!next)
6661                         return -EIO;
6662                 btrfs_tree_lock(next);
6663                 btrfs_set_lock_blocking(next);
6664         }
6665
6666         level--;
6667         BUG_ON(level != btrfs_header_level(next));
6668         path->nodes[level] = next;
6669         path->slots[level] = 0;
6670         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6671         wc->level = level;
6672         if (wc->level == 1)
6673                 wc->reada_slot = 0;
6674         return 0;
6675 skip:
6676         wc->refs[level - 1] = 0;
6677         wc->flags[level - 1] = 0;
6678         if (wc->stage == DROP_REFERENCE) {
6679                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6680                         parent = path->nodes[level]->start;
6681                 } else {
6682                         BUG_ON(root->root_key.objectid !=
6683                                btrfs_header_owner(path->nodes[level]));
6684                         parent = 0;
6685                 }
6686
6687                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6688                                 root->root_key.objectid, level - 1, 0, 0);
6689                 BUG_ON(ret); /* -ENOMEM */
6690         }
6691         btrfs_tree_unlock(next);
6692         free_extent_buffer(next);
6693         *lookup_info = 1;
6694         return 1;
6695 }
6696
6697 /*
6698  * hepler to process tree block while walking up the tree.
6699  *
6700  * when wc->stage == DROP_REFERENCE, this function drops
6701  * reference count on the block.
6702  *
6703  * when wc->stage == UPDATE_BACKREF, this function changes
6704  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6705  * to UPDATE_BACKREF previously while processing the block.
6706  *
6707  * NOTE: return value 1 means we should stop walking up.
6708  */
6709 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6710                                  struct btrfs_root *root,
6711                                  struct btrfs_path *path,
6712                                  struct walk_control *wc)
6713 {
6714         int ret;
6715         int level = wc->level;
6716         struct extent_buffer *eb = path->nodes[level];
6717         u64 parent = 0;
6718
6719         if (wc->stage == UPDATE_BACKREF) {
6720                 BUG_ON(wc->shared_level < level);
6721                 if (level < wc->shared_level)
6722                         goto out;
6723
6724                 ret = find_next_key(path, level + 1, &wc->update_progress);
6725                 if (ret > 0)
6726                         wc->update_ref = 0;
6727
6728                 wc->stage = DROP_REFERENCE;
6729                 wc->shared_level = -1;
6730                 path->slots[level] = 0;
6731
6732                 /*
6733                  * check reference count again if the block isn't locked.
6734                  * we should start walking down the tree again if reference
6735                  * count is one.
6736                  */
6737                 if (!path->locks[level]) {
6738                         BUG_ON(level == 0);
6739                         btrfs_tree_lock(eb);
6740                         btrfs_set_lock_blocking(eb);
6741                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6742
6743                         ret = btrfs_lookup_extent_info(trans, root,
6744                                                        eb->start, eb->len,
6745                                                        &wc->refs[level],
6746                                                        &wc->flags[level]);
6747                         if (ret < 0) {
6748                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6749                                 return ret;
6750                         }
6751                         BUG_ON(wc->refs[level] == 0);
6752                         if (wc->refs[level] == 1) {
6753                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6754                                 return 1;
6755                         }
6756                 }
6757         }
6758
6759         /* wc->stage == DROP_REFERENCE */
6760         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6761
6762         if (wc->refs[level] == 1) {
6763                 if (level == 0) {
6764                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6765                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6766                                                     wc->for_reloc);
6767                         else
6768                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6769                                                     wc->for_reloc);
6770                         BUG_ON(ret); /* -ENOMEM */
6771                 }
6772                 /* make block locked assertion in clean_tree_block happy */
6773                 if (!path->locks[level] &&
6774                     btrfs_header_generation(eb) == trans->transid) {
6775                         btrfs_tree_lock(eb);
6776                         btrfs_set_lock_blocking(eb);
6777                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6778                 }
6779                 clean_tree_block(trans, root, eb);
6780         }
6781
6782         if (eb == root->node) {
6783                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6784                         parent = eb->start;
6785                 else
6786                         BUG_ON(root->root_key.objectid !=
6787                                btrfs_header_owner(eb));
6788         } else {
6789                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6790                         parent = path->nodes[level + 1]->start;
6791                 else
6792                         BUG_ON(root->root_key.objectid !=
6793                                btrfs_header_owner(path->nodes[level + 1]));
6794         }
6795
6796         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6797 out:
6798         wc->refs[level] = 0;
6799         wc->flags[level] = 0;
6800         return 0;
6801 }
6802
6803 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6804                                    struct btrfs_root *root,
6805                                    struct btrfs_path *path,
6806                                    struct walk_control *wc)
6807 {
6808         int level = wc->level;
6809         int lookup_info = 1;
6810         int ret;
6811
6812         while (level >= 0) {
6813                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6814                 if (ret > 0)
6815                         break;
6816
6817                 if (level == 0)
6818                         break;
6819
6820                 if (path->slots[level] >=
6821                     btrfs_header_nritems(path->nodes[level]))
6822                         break;
6823
6824                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6825                 if (ret > 0) {
6826                         path->slots[level]++;
6827                         continue;
6828                 } else if (ret < 0)
6829                         return ret;
6830                 level = wc->level;
6831         }
6832         return 0;
6833 }
6834
6835 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6836                                  struct btrfs_root *root,
6837                                  struct btrfs_path *path,
6838                                  struct walk_control *wc, int max_level)
6839 {
6840         int level = wc->level;
6841         int ret;
6842
6843         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6844         while (level < max_level && path->nodes[level]) {
6845                 wc->level = level;
6846                 if (path->slots[level] + 1 <
6847                     btrfs_header_nritems(path->nodes[level])) {
6848                         path->slots[level]++;
6849                         return 0;
6850                 } else {
6851                         ret = walk_up_proc(trans, root, path, wc);
6852                         if (ret > 0)
6853                                 return 0;
6854
6855                         if (path->locks[level]) {
6856                                 btrfs_tree_unlock_rw(path->nodes[level],
6857                                                      path->locks[level]);
6858                                 path->locks[level] = 0;
6859                         }
6860                         free_extent_buffer(path->nodes[level]);
6861                         path->nodes[level] = NULL;
6862                         level++;
6863                 }
6864         }
6865         return 1;
6866 }
6867
6868 /*
6869  * drop a subvolume tree.
6870  *
6871  * this function traverses the tree freeing any blocks that only
6872  * referenced by the tree.
6873  *
6874  * when a shared tree block is found. this function decreases its
6875  * reference count by one. if update_ref is true, this function
6876  * also make sure backrefs for the shared block and all lower level
6877  * blocks are properly updated.
6878  */
6879 int btrfs_drop_snapshot(struct btrfs_root *root,
6880                          struct btrfs_block_rsv *block_rsv, int update_ref,
6881                          int for_reloc)
6882 {
6883         struct btrfs_path *path;
6884         struct btrfs_trans_handle *trans;
6885         struct btrfs_root *tree_root = root->fs_info->tree_root;
6886         struct btrfs_root_item *root_item = &root->root_item;
6887         struct walk_control *wc;
6888         struct btrfs_key key;
6889         int err = 0;
6890         int ret;
6891         int level;
6892
6893         path = btrfs_alloc_path();
6894         if (!path) {
6895                 err = -ENOMEM;
6896                 goto out;
6897         }
6898
6899         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6900         if (!wc) {
6901                 btrfs_free_path(path);
6902                 err = -ENOMEM;
6903                 goto out;
6904         }
6905
6906         trans = btrfs_start_transaction(tree_root, 0);
6907         if (IS_ERR(trans)) {
6908                 err = PTR_ERR(trans);
6909                 goto out_free;
6910         }
6911
6912         if (block_rsv)
6913                 trans->block_rsv = block_rsv;
6914
6915         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6916                 level = btrfs_header_level(root->node);
6917                 path->nodes[level] = btrfs_lock_root_node(root);
6918                 btrfs_set_lock_blocking(path->nodes[level]);
6919                 path->slots[level] = 0;
6920                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6921                 memset(&wc->update_progress, 0,
6922                        sizeof(wc->update_progress));
6923         } else {
6924                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6925                 memcpy(&wc->update_progress, &key,
6926                        sizeof(wc->update_progress));
6927
6928                 level = root_item->drop_level;
6929                 BUG_ON(level == 0);
6930                 path->lowest_level = level;
6931                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6932                 path->lowest_level = 0;
6933                 if (ret < 0) {
6934                         err = ret;
6935                         goto out_end_trans;
6936                 }
6937                 WARN_ON(ret > 0);
6938
6939                 /*
6940                  * unlock our path, this is safe because only this
6941                  * function is allowed to delete this snapshot
6942                  */
6943                 btrfs_unlock_up_safe(path, 0);
6944
6945                 level = btrfs_header_level(root->node);
6946                 while (1) {
6947                         btrfs_tree_lock(path->nodes[level]);
6948                         btrfs_set_lock_blocking(path->nodes[level]);
6949
6950                         ret = btrfs_lookup_extent_info(trans, root,
6951                                                 path->nodes[level]->start,
6952                                                 path->nodes[level]->len,
6953                                                 &wc->refs[level],
6954                                                 &wc->flags[level]);
6955                         if (ret < 0) {
6956                                 err = ret;
6957                                 goto out_end_trans;
6958                         }
6959                         BUG_ON(wc->refs[level] == 0);
6960
6961                         if (level == root_item->drop_level)
6962                                 break;
6963
6964                         btrfs_tree_unlock(path->nodes[level]);
6965                         WARN_ON(wc->refs[level] != 1);
6966                         level--;
6967                 }
6968         }
6969
6970         wc->level = level;
6971         wc->shared_level = -1;
6972         wc->stage = DROP_REFERENCE;
6973         wc->update_ref = update_ref;
6974         wc->keep_locks = 0;
6975         wc->for_reloc = for_reloc;
6976         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6977
6978         while (1) {
6979                 ret = walk_down_tree(trans, root, path, wc);
6980                 if (ret < 0) {
6981                         err = ret;
6982                         break;
6983                 }
6984
6985                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6986                 if (ret < 0) {
6987                         err = ret;
6988                         break;
6989                 }
6990
6991                 if (ret > 0) {
6992                         BUG_ON(wc->stage != DROP_REFERENCE);
6993                         break;
6994                 }
6995
6996                 if (wc->stage == DROP_REFERENCE) {
6997                         level = wc->level;
6998                         btrfs_node_key(path->nodes[level],
6999                                        &root_item->drop_progress,
7000                                        path->slots[level]);
7001                         root_item->drop_level = level;
7002                 }
7003
7004                 BUG_ON(wc->level == 0);
7005                 if (btrfs_should_end_transaction(trans, tree_root)) {
7006                         ret = btrfs_update_root(trans, tree_root,
7007                                                 &root->root_key,
7008                                                 root_item);
7009                         if (ret) {
7010                                 btrfs_abort_transaction(trans, tree_root, ret);
7011                                 err = ret;
7012                                 goto out_end_trans;
7013                         }
7014
7015                         btrfs_end_transaction_throttle(trans, tree_root);
7016                         trans = btrfs_start_transaction(tree_root, 0);
7017                         if (IS_ERR(trans)) {
7018                                 err = PTR_ERR(trans);
7019                                 goto out_free;
7020                         }
7021                         if (block_rsv)
7022                                 trans->block_rsv = block_rsv;
7023                 }
7024         }
7025         btrfs_release_path(path);
7026         if (err)
7027                 goto out_end_trans;
7028
7029         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7030         if (ret) {
7031                 btrfs_abort_transaction(trans, tree_root, ret);
7032                 goto out_end_trans;
7033         }
7034
7035         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7036                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
7037                                            NULL, NULL);
7038                 if (ret < 0) {
7039                         btrfs_abort_transaction(trans, tree_root, ret);
7040                         err = ret;
7041                         goto out_end_trans;
7042                 } else if (ret > 0) {
7043                         /* if we fail to delete the orphan item this time
7044                          * around, it'll get picked up the next time.
7045                          *
7046                          * The most common failure here is just -ENOENT.
7047                          */
7048                         btrfs_del_orphan_item(trans, tree_root,
7049                                               root->root_key.objectid);
7050                 }
7051         }
7052
7053         if (root->in_radix) {
7054                 btrfs_free_fs_root(tree_root->fs_info, root);
7055         } else {
7056                 free_extent_buffer(root->node);
7057                 free_extent_buffer(root->commit_root);
7058                 kfree(root);
7059         }
7060 out_end_trans:
7061         btrfs_end_transaction_throttle(trans, tree_root);
7062 out_free:
7063         kfree(wc);
7064         btrfs_free_path(path);
7065 out:
7066         if (err)
7067                 btrfs_std_error(root->fs_info, err);
7068         return err;
7069 }
7070
7071 /*
7072  * drop subtree rooted at tree block 'node'.
7073  *
7074  * NOTE: this function will unlock and release tree block 'node'
7075  * only used by relocation code
7076  */
7077 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7078                         struct btrfs_root *root,
7079                         struct extent_buffer *node,
7080                         struct extent_buffer *parent)
7081 {
7082         struct btrfs_path *path;
7083         struct walk_control *wc;
7084         int level;
7085         int parent_level;
7086         int ret = 0;
7087         int wret;
7088
7089         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7090
7091         path = btrfs_alloc_path();
7092         if (!path)
7093                 return -ENOMEM;
7094
7095         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7096         if (!wc) {
7097                 btrfs_free_path(path);
7098                 return -ENOMEM;
7099         }
7100
7101         btrfs_assert_tree_locked(parent);
7102         parent_level = btrfs_header_level(parent);
7103         extent_buffer_get(parent);
7104         path->nodes[parent_level] = parent;
7105         path->slots[parent_level] = btrfs_header_nritems(parent);
7106
7107         btrfs_assert_tree_locked(node);
7108         level = btrfs_header_level(node);
7109         path->nodes[level] = node;
7110         path->slots[level] = 0;
7111         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7112
7113         wc->refs[parent_level] = 1;
7114         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7115         wc->level = level;
7116         wc->shared_level = -1;
7117         wc->stage = DROP_REFERENCE;
7118         wc->update_ref = 0;
7119         wc->keep_locks = 1;
7120         wc->for_reloc = 1;
7121         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7122
7123         while (1) {
7124                 wret = walk_down_tree(trans, root, path, wc);
7125                 if (wret < 0) {
7126                         ret = wret;
7127                         break;
7128                 }
7129
7130                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7131                 if (wret < 0)
7132                         ret = wret;
7133                 if (wret != 0)
7134                         break;
7135         }
7136
7137         kfree(wc);
7138         btrfs_free_path(path);
7139         return ret;
7140 }
7141
7142 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7143 {
7144         u64 num_devices;
7145         u64 stripped;
7146
7147         /*
7148          * if restripe for this chunk_type is on pick target profile and
7149          * return, otherwise do the usual balance
7150          */
7151         stripped = get_restripe_target(root->fs_info, flags);
7152         if (stripped)
7153                 return extended_to_chunk(stripped);
7154
7155         /*
7156          * we add in the count of missing devices because we want
7157          * to make sure that any RAID levels on a degraded FS
7158          * continue to be honored.
7159          */
7160         num_devices = root->fs_info->fs_devices->rw_devices +
7161                 root->fs_info->fs_devices->missing_devices;
7162
7163         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7164                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7165
7166         if (num_devices == 1) {
7167                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7168                 stripped = flags & ~stripped;
7169
7170                 /* turn raid0 into single device chunks */
7171                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7172                         return stripped;
7173
7174                 /* turn mirroring into duplication */
7175                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7176                              BTRFS_BLOCK_GROUP_RAID10))
7177                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7178         } else {
7179                 /* they already had raid on here, just return */
7180                 if (flags & stripped)
7181                         return flags;
7182
7183                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7184                 stripped = flags & ~stripped;
7185
7186                 /* switch duplicated blocks with raid1 */
7187                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7188                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7189
7190                 /* this is drive concat, leave it alone */
7191         }
7192
7193         return flags;
7194 }
7195
7196 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7197 {
7198         struct btrfs_space_info *sinfo = cache->space_info;
7199         u64 num_bytes;
7200         u64 min_allocable_bytes;
7201         int ret = -ENOSPC;
7202
7203
7204         /*
7205          * We need some metadata space and system metadata space for
7206          * allocating chunks in some corner cases until we force to set
7207          * it to be readonly.
7208          */
7209         if ((sinfo->flags &
7210              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7211             !force)
7212                 min_allocable_bytes = 1 * 1024 * 1024;
7213         else
7214                 min_allocable_bytes = 0;
7215
7216         spin_lock(&sinfo->lock);
7217         spin_lock(&cache->lock);
7218
7219         if (cache->ro) {
7220                 ret = 0;
7221                 goto out;
7222         }
7223
7224         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7225                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7226
7227         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7228             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7229             min_allocable_bytes <= sinfo->total_bytes) {
7230                 sinfo->bytes_readonly += num_bytes;
7231                 cache->ro = 1;
7232                 ret = 0;
7233         }
7234 out:
7235         spin_unlock(&cache->lock);
7236         spin_unlock(&sinfo->lock);
7237         return ret;
7238 }
7239
7240 int btrfs_set_block_group_ro(struct btrfs_root *root,
7241                              struct btrfs_block_group_cache *cache)
7242
7243 {
7244         struct btrfs_trans_handle *trans;
7245         u64 alloc_flags;
7246         int ret;
7247
7248         BUG_ON(cache->ro);
7249
7250         trans = btrfs_join_transaction(root);
7251         if (IS_ERR(trans))
7252                 return PTR_ERR(trans);
7253
7254         alloc_flags = update_block_group_flags(root, cache->flags);
7255         if (alloc_flags != cache->flags) {
7256                 ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7257                                      CHUNK_ALLOC_FORCE);
7258                 if (ret < 0)
7259                         goto out;
7260         }
7261
7262         ret = set_block_group_ro(cache, 0);
7263         if (!ret)
7264                 goto out;
7265         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7266         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7267                              CHUNK_ALLOC_FORCE);
7268         if (ret < 0)
7269                 goto out;
7270         ret = set_block_group_ro(cache, 0);
7271 out:
7272         btrfs_end_transaction(trans, root);
7273         return ret;
7274 }
7275
7276 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7277                             struct btrfs_root *root, u64 type)
7278 {
7279         u64 alloc_flags = get_alloc_profile(root, type);
7280         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7281                               CHUNK_ALLOC_FORCE);
7282 }
7283
7284 /*
7285  * helper to account the unused space of all the readonly block group in the
7286  * list. takes mirrors into account.
7287  */
7288 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7289 {
7290         struct btrfs_block_group_cache *block_group;
7291         u64 free_bytes = 0;
7292         int factor;
7293
7294         list_for_each_entry(block_group, groups_list, list) {
7295                 spin_lock(&block_group->lock);
7296
7297                 if (!block_group->ro) {
7298                         spin_unlock(&block_group->lock);
7299                         continue;
7300                 }
7301
7302                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7303                                           BTRFS_BLOCK_GROUP_RAID10 |
7304                                           BTRFS_BLOCK_GROUP_DUP))
7305                         factor = 2;
7306                 else
7307                         factor = 1;
7308
7309                 free_bytes += (block_group->key.offset -
7310                                btrfs_block_group_used(&block_group->item)) *
7311                                factor;
7312
7313                 spin_unlock(&block_group->lock);
7314         }
7315
7316         return free_bytes;
7317 }
7318
7319 /*
7320  * helper to account the unused space of all the readonly block group in the
7321  * space_info. takes mirrors into account.
7322  */
7323 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7324 {
7325         int i;
7326         u64 free_bytes = 0;
7327
7328         spin_lock(&sinfo->lock);
7329
7330         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7331                 if (!list_empty(&sinfo->block_groups[i]))
7332                         free_bytes += __btrfs_get_ro_block_group_free_space(
7333                                                 &sinfo->block_groups[i]);
7334
7335         spin_unlock(&sinfo->lock);
7336
7337         return free_bytes;
7338 }
7339
7340 void btrfs_set_block_group_rw(struct btrfs_root *root,
7341                               struct btrfs_block_group_cache *cache)
7342 {
7343         struct btrfs_space_info *sinfo = cache->space_info;
7344         u64 num_bytes;
7345
7346         BUG_ON(!cache->ro);
7347
7348         spin_lock(&sinfo->lock);
7349         spin_lock(&cache->lock);
7350         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7351                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7352         sinfo->bytes_readonly -= num_bytes;
7353         cache->ro = 0;
7354         spin_unlock(&cache->lock);
7355         spin_unlock(&sinfo->lock);
7356 }
7357
7358 /*
7359  * checks to see if its even possible to relocate this block group.
7360  *
7361  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7362  * ok to go ahead and try.
7363  */
7364 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7365 {
7366         struct btrfs_block_group_cache *block_group;
7367         struct btrfs_space_info *space_info;
7368         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7369         struct btrfs_device *device;
7370         u64 min_free;
7371         u64 dev_min = 1;
7372         u64 dev_nr = 0;
7373         u64 target;
7374         int index;
7375         int full = 0;
7376         int ret = 0;
7377
7378         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7379
7380         /* odd, couldn't find the block group, leave it alone */
7381         if (!block_group)
7382                 return -1;
7383
7384         min_free = btrfs_block_group_used(&block_group->item);
7385
7386         /* no bytes used, we're good */
7387         if (!min_free)
7388                 goto out;
7389
7390         space_info = block_group->space_info;
7391         spin_lock(&space_info->lock);
7392
7393         full = space_info->full;
7394
7395         /*
7396          * if this is the last block group we have in this space, we can't
7397          * relocate it unless we're able to allocate a new chunk below.
7398          *
7399          * Otherwise, we need to make sure we have room in the space to handle
7400          * all of the extents from this block group.  If we can, we're good
7401          */
7402         if ((space_info->total_bytes != block_group->key.offset) &&
7403             (space_info->bytes_used + space_info->bytes_reserved +
7404              space_info->bytes_pinned + space_info->bytes_readonly +
7405              min_free < space_info->total_bytes)) {
7406                 spin_unlock(&space_info->lock);
7407                 goto out;
7408         }
7409         spin_unlock(&space_info->lock);
7410
7411         /*
7412          * ok we don't have enough space, but maybe we have free space on our
7413          * devices to allocate new chunks for relocation, so loop through our
7414          * alloc devices and guess if we have enough space.  if this block
7415          * group is going to be restriped, run checks against the target
7416          * profile instead of the current one.
7417          */
7418         ret = -1;
7419
7420         /*
7421          * index:
7422          *      0: raid10
7423          *      1: raid1
7424          *      2: dup
7425          *      3: raid0
7426          *      4: single
7427          */
7428         target = get_restripe_target(root->fs_info, block_group->flags);
7429         if (target) {
7430                 index = __get_block_group_index(extended_to_chunk(target));
7431         } else {
7432                 /*
7433                  * this is just a balance, so if we were marked as full
7434                  * we know there is no space for a new chunk
7435                  */
7436                 if (full)
7437                         goto out;
7438
7439                 index = get_block_group_index(block_group);
7440         }
7441
7442         if (index == 0) {
7443                 dev_min = 4;
7444                 /* Divide by 2 */
7445                 min_free >>= 1;
7446         } else if (index == 1) {
7447                 dev_min = 2;
7448         } else if (index == 2) {
7449                 /* Multiply by 2 */
7450                 min_free <<= 1;
7451         } else if (index == 3) {
7452                 dev_min = fs_devices->rw_devices;
7453                 do_div(min_free, dev_min);
7454         }
7455
7456         mutex_lock(&root->fs_info->chunk_mutex);
7457         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7458                 u64 dev_offset;
7459
7460                 /*
7461                  * check to make sure we can actually find a chunk with enough
7462                  * space to fit our block group in.
7463                  */
7464                 if (device->total_bytes > device->bytes_used + min_free) {
7465                         ret = find_free_dev_extent(device, min_free,
7466                                                    &dev_offset, NULL);
7467                         if (!ret)
7468                                 dev_nr++;
7469
7470                         if (dev_nr >= dev_min)
7471                                 break;
7472
7473                         ret = -1;
7474                 }
7475         }
7476         mutex_unlock(&root->fs_info->chunk_mutex);
7477 out:
7478         btrfs_put_block_group(block_group);
7479         return ret;
7480 }
7481
7482 static int find_first_block_group(struct btrfs_root *root,
7483                 struct btrfs_path *path, struct btrfs_key *key)
7484 {
7485         int ret = 0;
7486         struct btrfs_key found_key;
7487         struct extent_buffer *leaf;
7488         int slot;
7489
7490         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7491         if (ret < 0)
7492                 goto out;
7493
7494         while (1) {
7495                 slot = path->slots[0];
7496                 leaf = path->nodes[0];
7497                 if (slot >= btrfs_header_nritems(leaf)) {
7498                         ret = btrfs_next_leaf(root, path);
7499                         if (ret == 0)
7500                                 continue;
7501                         if (ret < 0)
7502                                 goto out;
7503                         break;
7504                 }
7505                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7506
7507                 if (found_key.objectid >= key->objectid &&
7508                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7509                         ret = 0;
7510                         goto out;
7511                 }
7512                 path->slots[0]++;
7513         }
7514 out:
7515         return ret;
7516 }
7517
7518 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7519 {
7520         struct btrfs_block_group_cache *block_group;
7521         u64 last = 0;
7522
7523         while (1) {
7524                 struct inode *inode;
7525
7526                 block_group = btrfs_lookup_first_block_group(info, last);
7527                 while (block_group) {
7528                         spin_lock(&block_group->lock);
7529                         if (block_group->iref)
7530                                 break;
7531                         spin_unlock(&block_group->lock);
7532                         block_group = next_block_group(info->tree_root,
7533                                                        block_group);
7534                 }
7535                 if (!block_group) {
7536                         if (last == 0)
7537                                 break;
7538                         last = 0;
7539                         continue;
7540                 }
7541
7542                 inode = block_group->inode;
7543                 block_group->iref = 0;
7544                 block_group->inode = NULL;
7545                 spin_unlock(&block_group->lock);
7546                 iput(inode);
7547                 last = block_group->key.objectid + block_group->key.offset;
7548                 btrfs_put_block_group(block_group);
7549         }
7550 }
7551
7552 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7553 {
7554         struct btrfs_block_group_cache *block_group;
7555         struct btrfs_space_info *space_info;
7556         struct btrfs_caching_control *caching_ctl;
7557         struct rb_node *n;
7558
7559         down_write(&info->extent_commit_sem);
7560         while (!list_empty(&info->caching_block_groups)) {
7561                 caching_ctl = list_entry(info->caching_block_groups.next,
7562                                          struct btrfs_caching_control, list);
7563                 list_del(&caching_ctl->list);
7564                 put_caching_control(caching_ctl);
7565         }
7566         up_write(&info->extent_commit_sem);
7567
7568         spin_lock(&info->block_group_cache_lock);
7569         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7570                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7571                                        cache_node);
7572                 rb_erase(&block_group->cache_node,
7573                          &info->block_group_cache_tree);
7574                 spin_unlock(&info->block_group_cache_lock);
7575
7576                 down_write(&block_group->space_info->groups_sem);
7577                 list_del(&block_group->list);
7578                 up_write(&block_group->space_info->groups_sem);
7579
7580                 if (block_group->cached == BTRFS_CACHE_STARTED)
7581                         wait_block_group_cache_done(block_group);
7582
7583                 /*
7584                  * We haven't cached this block group, which means we could
7585                  * possibly have excluded extents on this block group.
7586                  */
7587                 if (block_group->cached == BTRFS_CACHE_NO)
7588                         free_excluded_extents(info->extent_root, block_group);
7589
7590                 btrfs_remove_free_space_cache(block_group);
7591                 btrfs_put_block_group(block_group);
7592
7593                 spin_lock(&info->block_group_cache_lock);
7594         }
7595         spin_unlock(&info->block_group_cache_lock);
7596
7597         /* now that all the block groups are freed, go through and
7598          * free all the space_info structs.  This is only called during
7599          * the final stages of unmount, and so we know nobody is
7600          * using them.  We call synchronize_rcu() once before we start,
7601          * just to be on the safe side.
7602          */
7603         synchronize_rcu();
7604
7605         release_global_block_rsv(info);
7606
7607         while(!list_empty(&info->space_info)) {
7608                 space_info = list_entry(info->space_info.next,
7609                                         struct btrfs_space_info,
7610                                         list);
7611                 if (space_info->bytes_pinned > 0 ||
7612                     space_info->bytes_reserved > 0 ||
7613                     space_info->bytes_may_use > 0) {
7614                         WARN_ON(1);
7615                         dump_space_info(space_info, 0, 0);
7616                 }
7617                 list_del(&space_info->list);
7618                 kfree(space_info);
7619         }
7620         return 0;
7621 }
7622
7623 static void __link_block_group(struct btrfs_space_info *space_info,
7624                                struct btrfs_block_group_cache *cache)
7625 {
7626         int index = get_block_group_index(cache);
7627
7628         down_write(&space_info->groups_sem);
7629         list_add_tail(&cache->list, &space_info->block_groups[index]);
7630         up_write(&space_info->groups_sem);
7631 }
7632
7633 int btrfs_read_block_groups(struct btrfs_root *root)
7634 {
7635         struct btrfs_path *path;
7636         int ret;
7637         struct btrfs_block_group_cache *cache;
7638         struct btrfs_fs_info *info = root->fs_info;
7639         struct btrfs_space_info *space_info;
7640         struct btrfs_key key;
7641         struct btrfs_key found_key;
7642         struct extent_buffer *leaf;
7643         int need_clear = 0;
7644         u64 cache_gen;
7645
7646         root = info->extent_root;
7647         key.objectid = 0;
7648         key.offset = 0;
7649         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7650         path = btrfs_alloc_path();
7651         if (!path)
7652                 return -ENOMEM;
7653         path->reada = 1;
7654
7655         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7656         if (btrfs_test_opt(root, SPACE_CACHE) &&
7657             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7658                 need_clear = 1;
7659         if (btrfs_test_opt(root, CLEAR_CACHE))
7660                 need_clear = 1;
7661
7662         while (1) {
7663                 ret = find_first_block_group(root, path, &key);
7664                 if (ret > 0)
7665                         break;
7666                 if (ret != 0)
7667                         goto error;
7668                 leaf = path->nodes[0];
7669                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7670                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7671                 if (!cache) {
7672                         ret = -ENOMEM;
7673                         goto error;
7674                 }
7675                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7676                                                 GFP_NOFS);
7677                 if (!cache->free_space_ctl) {
7678                         kfree(cache);
7679                         ret = -ENOMEM;
7680                         goto error;
7681                 }
7682
7683                 atomic_set(&cache->count, 1);
7684                 spin_lock_init(&cache->lock);
7685                 cache->fs_info = info;
7686                 INIT_LIST_HEAD(&cache->list);
7687                 INIT_LIST_HEAD(&cache->cluster_list);
7688
7689                 if (need_clear) {
7690                         /*
7691                          * When we mount with old space cache, we need to
7692                          * set BTRFS_DC_CLEAR and set dirty flag.
7693                          *
7694                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
7695                          *    truncate the old free space cache inode and
7696                          *    setup a new one.
7697                          * b) Setting 'dirty flag' makes sure that we flush
7698                          *    the new space cache info onto disk.
7699                          */
7700                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7701                         if (btrfs_test_opt(root, SPACE_CACHE))
7702                                 cache->dirty = 1;
7703                 }
7704
7705                 read_extent_buffer(leaf, &cache->item,
7706                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7707                                    sizeof(cache->item));
7708                 memcpy(&cache->key, &found_key, sizeof(found_key));
7709
7710                 key.objectid = found_key.objectid + found_key.offset;
7711                 btrfs_release_path(path);
7712                 cache->flags = btrfs_block_group_flags(&cache->item);
7713                 cache->sectorsize = root->sectorsize;
7714
7715                 btrfs_init_free_space_ctl(cache);
7716
7717                 /*
7718                  * We need to exclude the super stripes now so that the space
7719                  * info has super bytes accounted for, otherwise we'll think
7720                  * we have more space than we actually do.
7721                  */
7722                 exclude_super_stripes(root, cache);
7723
7724                 /*
7725                  * check for two cases, either we are full, and therefore
7726                  * don't need to bother with the caching work since we won't
7727                  * find any space, or we are empty, and we can just add all
7728                  * the space in and be done with it.  This saves us _alot_ of
7729                  * time, particularly in the full case.
7730                  */
7731                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7732                         cache->last_byte_to_unpin = (u64)-1;
7733                         cache->cached = BTRFS_CACHE_FINISHED;
7734                         free_excluded_extents(root, cache);
7735                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7736                         cache->last_byte_to_unpin = (u64)-1;
7737                         cache->cached = BTRFS_CACHE_FINISHED;
7738                         add_new_free_space(cache, root->fs_info,
7739                                            found_key.objectid,
7740                                            found_key.objectid +
7741                                            found_key.offset);
7742                         free_excluded_extents(root, cache);
7743                 }
7744
7745                 ret = update_space_info(info, cache->flags, found_key.offset,
7746                                         btrfs_block_group_used(&cache->item),
7747                                         &space_info);
7748                 BUG_ON(ret); /* -ENOMEM */
7749                 cache->space_info = space_info;
7750                 spin_lock(&cache->space_info->lock);
7751                 cache->space_info->bytes_readonly += cache->bytes_super;
7752                 spin_unlock(&cache->space_info->lock);
7753
7754                 __link_block_group(space_info, cache);
7755
7756                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7757                 BUG_ON(ret); /* Logic error */
7758
7759                 set_avail_alloc_bits(root->fs_info, cache->flags);
7760                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7761                         set_block_group_ro(cache, 1);
7762         }
7763
7764         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7765                 if (!(get_alloc_profile(root, space_info->flags) &
7766                       (BTRFS_BLOCK_GROUP_RAID10 |
7767                        BTRFS_BLOCK_GROUP_RAID1 |
7768                        BTRFS_BLOCK_GROUP_DUP)))
7769                         continue;
7770                 /*
7771                  * avoid allocating from un-mirrored block group if there are
7772                  * mirrored block groups.
7773                  */
7774                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7775                         set_block_group_ro(cache, 1);
7776                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7777                         set_block_group_ro(cache, 1);
7778         }
7779
7780         init_global_block_rsv(info);
7781         ret = 0;
7782 error:
7783         btrfs_free_path(path);
7784         return ret;
7785 }
7786
7787 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7788                            struct btrfs_root *root, u64 bytes_used,
7789                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7790                            u64 size)
7791 {
7792         int ret;
7793         struct btrfs_root *extent_root;
7794         struct btrfs_block_group_cache *cache;
7795
7796         extent_root = root->fs_info->extent_root;
7797
7798         root->fs_info->last_trans_log_full_commit = trans->transid;
7799
7800         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7801         if (!cache)
7802                 return -ENOMEM;
7803         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7804                                         GFP_NOFS);
7805         if (!cache->free_space_ctl) {
7806                 kfree(cache);
7807                 return -ENOMEM;
7808         }
7809
7810         cache->key.objectid = chunk_offset;
7811         cache->key.offset = size;
7812         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7813         cache->sectorsize = root->sectorsize;
7814         cache->fs_info = root->fs_info;
7815
7816         atomic_set(&cache->count, 1);
7817         spin_lock_init(&cache->lock);
7818         INIT_LIST_HEAD(&cache->list);
7819         INIT_LIST_HEAD(&cache->cluster_list);
7820
7821         btrfs_init_free_space_ctl(cache);
7822
7823         btrfs_set_block_group_used(&cache->item, bytes_used);
7824         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7825         cache->flags = type;
7826         btrfs_set_block_group_flags(&cache->item, type);
7827
7828         cache->last_byte_to_unpin = (u64)-1;
7829         cache->cached = BTRFS_CACHE_FINISHED;
7830         exclude_super_stripes(root, cache);
7831
7832         add_new_free_space(cache, root->fs_info, chunk_offset,
7833                            chunk_offset + size);
7834
7835         free_excluded_extents(root, cache);
7836
7837         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7838                                 &cache->space_info);
7839         BUG_ON(ret); /* -ENOMEM */
7840         update_global_block_rsv(root->fs_info);
7841
7842         spin_lock(&cache->space_info->lock);
7843         cache->space_info->bytes_readonly += cache->bytes_super;
7844         spin_unlock(&cache->space_info->lock);
7845
7846         __link_block_group(cache->space_info, cache);
7847
7848         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7849         BUG_ON(ret); /* Logic error */
7850
7851         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7852                                 sizeof(cache->item));
7853         if (ret) {
7854                 btrfs_abort_transaction(trans, extent_root, ret);
7855                 return ret;
7856         }
7857
7858         set_avail_alloc_bits(extent_root->fs_info, type);
7859
7860         return 0;
7861 }
7862
7863 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7864 {
7865         u64 extra_flags = chunk_to_extended(flags) &
7866                                 BTRFS_EXTENDED_PROFILE_MASK;
7867
7868         if (flags & BTRFS_BLOCK_GROUP_DATA)
7869                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7870         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7871                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7872         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7873                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7874 }
7875
7876 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7877                              struct btrfs_root *root, u64 group_start)
7878 {
7879         struct btrfs_path *path;
7880         struct btrfs_block_group_cache *block_group;
7881         struct btrfs_free_cluster *cluster;
7882         struct btrfs_root *tree_root = root->fs_info->tree_root;
7883         struct btrfs_key key;
7884         struct inode *inode;
7885         int ret;
7886         int index;
7887         int factor;
7888
7889         root = root->fs_info->extent_root;
7890
7891         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7892         BUG_ON(!block_group);
7893         BUG_ON(!block_group->ro);
7894
7895         /*
7896          * Free the reserved super bytes from this block group before
7897          * remove it.
7898          */
7899         free_excluded_extents(root, block_group);
7900
7901         memcpy(&key, &block_group->key, sizeof(key));
7902         index = get_block_group_index(block_group);
7903         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7904                                   BTRFS_BLOCK_GROUP_RAID1 |
7905                                   BTRFS_BLOCK_GROUP_RAID10))
7906                 factor = 2;
7907         else
7908                 factor = 1;
7909
7910         /* make sure this block group isn't part of an allocation cluster */
7911         cluster = &root->fs_info->data_alloc_cluster;
7912         spin_lock(&cluster->refill_lock);
7913         btrfs_return_cluster_to_free_space(block_group, cluster);
7914         spin_unlock(&cluster->refill_lock);
7915
7916         /*
7917          * make sure this block group isn't part of a metadata
7918          * allocation cluster
7919          */
7920         cluster = &root->fs_info->meta_alloc_cluster;
7921         spin_lock(&cluster->refill_lock);
7922         btrfs_return_cluster_to_free_space(block_group, cluster);
7923         spin_unlock(&cluster->refill_lock);
7924
7925         path = btrfs_alloc_path();
7926         if (!path) {
7927                 ret = -ENOMEM;
7928                 goto out;
7929         }
7930
7931         inode = lookup_free_space_inode(tree_root, block_group, path);
7932         if (!IS_ERR(inode)) {
7933                 ret = btrfs_orphan_add(trans, inode);
7934                 if (ret) {
7935                         btrfs_add_delayed_iput(inode);
7936                         goto out;
7937                 }
7938                 clear_nlink(inode);
7939                 /* One for the block groups ref */
7940                 spin_lock(&block_group->lock);
7941                 if (block_group->iref) {
7942                         block_group->iref = 0;
7943                         block_group->inode = NULL;
7944                         spin_unlock(&block_group->lock);
7945                         iput(inode);
7946                 } else {
7947                         spin_unlock(&block_group->lock);
7948                 }
7949                 /* One for our lookup ref */
7950                 btrfs_add_delayed_iput(inode);
7951         }
7952
7953         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7954         key.offset = block_group->key.objectid;
7955         key.type = 0;
7956
7957         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7958         if (ret < 0)
7959                 goto out;
7960         if (ret > 0)
7961                 btrfs_release_path(path);
7962         if (ret == 0) {
7963                 ret = btrfs_del_item(trans, tree_root, path);
7964                 if (ret)
7965                         goto out;
7966                 btrfs_release_path(path);
7967         }
7968
7969         spin_lock(&root->fs_info->block_group_cache_lock);
7970         rb_erase(&block_group->cache_node,
7971                  &root->fs_info->block_group_cache_tree);
7972         spin_unlock(&root->fs_info->block_group_cache_lock);
7973
7974         down_write(&block_group->space_info->groups_sem);
7975         /*
7976          * we must use list_del_init so people can check to see if they
7977          * are still on the list after taking the semaphore
7978          */
7979         list_del_init(&block_group->list);
7980         if (list_empty(&block_group->space_info->block_groups[index]))
7981                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7982         up_write(&block_group->space_info->groups_sem);
7983
7984         if (block_group->cached == BTRFS_CACHE_STARTED)
7985                 wait_block_group_cache_done(block_group);
7986
7987         btrfs_remove_free_space_cache(block_group);
7988
7989         spin_lock(&block_group->space_info->lock);
7990         block_group->space_info->total_bytes -= block_group->key.offset;
7991         block_group->space_info->bytes_readonly -= block_group->key.offset;
7992         block_group->space_info->disk_total -= block_group->key.offset * factor;
7993         spin_unlock(&block_group->space_info->lock);
7994
7995         memcpy(&key, &block_group->key, sizeof(key));
7996
7997         btrfs_clear_space_info_full(root->fs_info);
7998
7999         btrfs_put_block_group(block_group);
8000         btrfs_put_block_group(block_group);
8001
8002         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8003         if (ret > 0)
8004                 ret = -EIO;
8005         if (ret < 0)
8006                 goto out;
8007
8008         ret = btrfs_del_item(trans, root, path);
8009 out:
8010         btrfs_free_path(path);
8011         return ret;
8012 }
8013
8014 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8015 {
8016         struct btrfs_space_info *space_info;
8017         struct btrfs_super_block *disk_super;
8018         u64 features;
8019         u64 flags;
8020         int mixed = 0;
8021         int ret;
8022
8023         disk_super = fs_info->super_copy;
8024         if (!btrfs_super_root(disk_super))
8025                 return 1;
8026
8027         features = btrfs_super_incompat_flags(disk_super);
8028         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8029                 mixed = 1;
8030
8031         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8032         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8033         if (ret)
8034                 goto out;
8035
8036         if (mixed) {
8037                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8038                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8039         } else {
8040                 flags = BTRFS_BLOCK_GROUP_METADATA;
8041                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8042                 if (ret)
8043                         goto out;
8044
8045                 flags = BTRFS_BLOCK_GROUP_DATA;
8046                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8047         }
8048 out:
8049         return ret;
8050 }
8051
8052 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8053 {
8054         return unpin_extent_range(root, start, end);
8055 }
8056
8057 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8058                                u64 num_bytes, u64 *actual_bytes)
8059 {
8060         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8061 }
8062
8063 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8064 {
8065         struct btrfs_fs_info *fs_info = root->fs_info;
8066         struct btrfs_block_group_cache *cache = NULL;
8067         u64 group_trimmed;
8068         u64 start;
8069         u64 end;
8070         u64 trimmed = 0;
8071         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8072         int ret = 0;
8073
8074         /*
8075          * try to trim all FS space, our block group may start from non-zero.
8076          */
8077         if (range->len == total_bytes)
8078                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8079         else
8080                 cache = btrfs_lookup_block_group(fs_info, range->start);
8081
8082         while (cache) {
8083                 if (cache->key.objectid >= (range->start + range->len)) {
8084                         btrfs_put_block_group(cache);
8085                         break;
8086                 }
8087
8088                 start = max(range->start, cache->key.objectid);
8089                 end = min(range->start + range->len,
8090                                 cache->key.objectid + cache->key.offset);
8091
8092                 if (end - start >= range->minlen) {
8093                         if (!block_group_cache_done(cache)) {
8094                                 ret = cache_block_group(cache, NULL, root, 0);
8095                                 if (!ret)
8096                                         wait_block_group_cache_done(cache);
8097                         }
8098                         ret = btrfs_trim_block_group(cache,
8099                                                      &group_trimmed,
8100                                                      start,
8101                                                      end,
8102                                                      range->minlen);
8103
8104                         trimmed += group_trimmed;
8105                         if (ret) {
8106                                 btrfs_put_block_group(cache);
8107                                 break;
8108                         }
8109                 }
8110
8111                 cache = next_block_group(fs_info->tree_root, cache);
8112         }
8113
8114         range->len = trimmed;
8115         return ret;
8116 }