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                 /*
2322                  * we modified num_entries, but as we're currently running
2323                  * delayed refs, skip
2324                  *     wake_up(&delayed_refs->seq_wait);
2325                  * here.
2326                  */
2327                 spin_unlock(&delayed_refs->lock);
2328
2329                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2330                                           must_insert_reserved);
2331
2332                 btrfs_put_delayed_ref(ref);
2333                 kfree(extent_op);
2334                 count++;
2335
2336                 if (ret) {
2337                         printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
2338                         spin_lock(&delayed_refs->lock);
2339                         return ret;
2340                 }
2341
2342 next:
2343                 do_chunk_alloc(trans, fs_info->extent_root,
2344                                2 * 1024 * 1024,
2345                                btrfs_get_alloc_profile(root, 0),
2346                                CHUNK_ALLOC_NO_FORCE);
2347                 cond_resched();
2348                 spin_lock(&delayed_refs->lock);
2349         }
2350         return count;
2351 }
2352
2353 static void wait_for_more_refs(struct btrfs_fs_info *fs_info,
2354                                struct btrfs_delayed_ref_root *delayed_refs,
2355                                unsigned long num_refs,
2356                                struct list_head *first_seq)
2357 {
2358         spin_unlock(&delayed_refs->lock);
2359         pr_debug("waiting for more refs (num %ld, first %p)\n",
2360                  num_refs, first_seq);
2361         wait_event(fs_info->tree_mod_seq_wait,
2362                    num_refs != delayed_refs->num_entries ||
2363                    fs_info->tree_mod_seq_list.next != first_seq);
2364         pr_debug("done waiting for more refs (num %ld, first %p)\n",
2365                  delayed_refs->num_entries, fs_info->tree_mod_seq_list.next);
2366         spin_lock(&delayed_refs->lock);
2367 }
2368
2369 #ifdef SCRAMBLE_DELAYED_REFS
2370 /*
2371  * Normally delayed refs get processed in ascending bytenr order. This
2372  * correlates in most cases to the order added. To expose dependencies on this
2373  * order, we start to process the tree in the middle instead of the beginning
2374  */
2375 static u64 find_middle(struct rb_root *root)
2376 {
2377         struct rb_node *n = root->rb_node;
2378         struct btrfs_delayed_ref_node *entry;
2379         int alt = 1;
2380         u64 middle;
2381         u64 first = 0, last = 0;
2382
2383         n = rb_first(root);
2384         if (n) {
2385                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2386                 first = entry->bytenr;
2387         }
2388         n = rb_last(root);
2389         if (n) {
2390                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2391                 last = entry->bytenr;
2392         }
2393         n = root->rb_node;
2394
2395         while (n) {
2396                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2397                 WARN_ON(!entry->in_tree);
2398
2399                 middle = entry->bytenr;
2400
2401                 if (alt)
2402                         n = n->rb_left;
2403                 else
2404                         n = n->rb_right;
2405
2406                 alt = 1 - alt;
2407         }
2408         return middle;
2409 }
2410 #endif
2411
2412 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2413                                          struct btrfs_fs_info *fs_info)
2414 {
2415         struct qgroup_update *qgroup_update;
2416         int ret = 0;
2417
2418         if (list_empty(&trans->qgroup_ref_list) !=
2419             !trans->delayed_ref_elem.seq) {
2420                 /* list without seq or seq without list */
2421                 printk(KERN_ERR "btrfs: qgroup accounting update error, list is%s empty, seq is %llu\n",
2422                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2423                         trans->delayed_ref_elem.seq);
2424                 BUG();
2425         }
2426
2427         if (!trans->delayed_ref_elem.seq)
2428                 return 0;
2429
2430         while (!list_empty(&trans->qgroup_ref_list)) {
2431                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2432                                                  struct qgroup_update, list);
2433                 list_del(&qgroup_update->list);
2434                 if (!ret)
2435                         ret = btrfs_qgroup_account_ref(
2436                                         trans, fs_info, qgroup_update->node,
2437                                         qgroup_update->extent_op);
2438                 kfree(qgroup_update);
2439         }
2440
2441         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2442
2443         return ret;
2444 }
2445
2446 /*
2447  * this starts processing the delayed reference count updates and
2448  * extent insertions we have queued up so far.  count can be
2449  * 0, which means to process everything in the tree at the start
2450  * of the run (but not newly added entries), or it can be some target
2451  * number you'd like to process.
2452  *
2453  * Returns 0 on success or if called with an aborted transaction
2454  * Returns <0 on error and aborts the transaction
2455  */
2456 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2457                            struct btrfs_root *root, unsigned long count)
2458 {
2459         struct rb_node *node;
2460         struct btrfs_delayed_ref_root *delayed_refs;
2461         struct btrfs_delayed_ref_node *ref;
2462         struct list_head cluster;
2463         struct list_head *first_seq = NULL;
2464         int ret;
2465         u64 delayed_start;
2466         int run_all = count == (unsigned long)-1;
2467         int run_most = 0;
2468         unsigned long num_refs = 0;
2469         int consider_waiting;
2470
2471         /* We'll clean this up in btrfs_cleanup_transaction */
2472         if (trans->aborted)
2473                 return 0;
2474
2475         if (root == root->fs_info->extent_root)
2476                 root = root->fs_info->tree_root;
2477
2478         do_chunk_alloc(trans, root->fs_info->extent_root,
2479                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2480                        CHUNK_ALLOC_NO_FORCE);
2481
2482         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2483
2484         delayed_refs = &trans->transaction->delayed_refs;
2485         INIT_LIST_HEAD(&cluster);
2486 again:
2487         consider_waiting = 0;
2488         spin_lock(&delayed_refs->lock);
2489
2490 #ifdef SCRAMBLE_DELAYED_REFS
2491         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2492 #endif
2493
2494         if (count == 0) {
2495                 count = delayed_refs->num_entries * 2;
2496                 run_most = 1;
2497         }
2498         while (1) {
2499                 if (!(run_all || run_most) &&
2500                     delayed_refs->num_heads_ready < 64)
2501                         break;
2502
2503                 /*
2504                  * go find something we can process in the rbtree.  We start at
2505                  * the beginning of the tree, and then build a cluster
2506                  * of refs to process starting at the first one we are able to
2507                  * lock
2508                  */
2509                 delayed_start = delayed_refs->run_delayed_start;
2510                 ret = btrfs_find_ref_cluster(trans, &cluster,
2511                                              delayed_refs->run_delayed_start);
2512                 if (ret)
2513                         break;
2514
2515                 if (delayed_start >= delayed_refs->run_delayed_start) {
2516                         if (consider_waiting == 0) {
2517                                 /*
2518                                  * btrfs_find_ref_cluster looped. let's do one
2519                                  * more cycle. if we don't run any delayed ref
2520                                  * during that cycle (because we can't because
2521                                  * all of them are blocked) and if the number of
2522                                  * refs doesn't change, we avoid busy waiting.
2523                                  */
2524                                 consider_waiting = 1;
2525                                 num_refs = delayed_refs->num_entries;
2526                                 first_seq = root->fs_info->tree_mod_seq_list.next;
2527                         } else {
2528                                 wait_for_more_refs(root->fs_info, delayed_refs,
2529                                                    num_refs, first_seq);
2530                                 /*
2531                                  * after waiting, things have changed. we
2532                                  * dropped the lock and someone else might have
2533                                  * run some refs, built new clusters and so on.
2534                                  * therefore, we restart staleness detection.
2535                                  */
2536                                 consider_waiting = 0;
2537                         }
2538                 }
2539
2540                 ret = run_clustered_refs(trans, root, &cluster);
2541                 if (ret < 0) {
2542                         spin_unlock(&delayed_refs->lock);
2543                         btrfs_abort_transaction(trans, root, ret);
2544                         return ret;
2545                 }
2546
2547                 count -= min_t(unsigned long, ret, count);
2548
2549                 if (count == 0)
2550                         break;
2551
2552                 if (ret || delayed_refs->run_delayed_start == 0) {
2553                         /* refs were run, let's reset staleness detection */
2554                         consider_waiting = 0;
2555                 }
2556         }
2557
2558         if (run_all) {
2559                 node = rb_first(&delayed_refs->root);
2560                 if (!node)
2561                         goto out;
2562                 count = (unsigned long)-1;
2563
2564                 while (node) {
2565                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2566                                        rb_node);
2567                         if (btrfs_delayed_ref_is_head(ref)) {
2568                                 struct btrfs_delayed_ref_head *head;
2569
2570                                 head = btrfs_delayed_node_to_head(ref);
2571                                 atomic_inc(&ref->refs);
2572
2573                                 spin_unlock(&delayed_refs->lock);
2574                                 /*
2575                                  * Mutex was contended, block until it's
2576                                  * released and try again
2577                                  */
2578                                 mutex_lock(&head->mutex);
2579                                 mutex_unlock(&head->mutex);
2580
2581                                 btrfs_put_delayed_ref(ref);
2582                                 cond_resched();
2583                                 goto again;
2584                         }
2585                         node = rb_next(node);
2586                 }
2587                 spin_unlock(&delayed_refs->lock);
2588                 schedule_timeout(1);
2589                 goto again;
2590         }
2591 out:
2592         spin_unlock(&delayed_refs->lock);
2593         assert_qgroups_uptodate(trans);
2594         return 0;
2595 }
2596
2597 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2598                                 struct btrfs_root *root,
2599                                 u64 bytenr, u64 num_bytes, u64 flags,
2600                                 int is_data)
2601 {
2602         struct btrfs_delayed_extent_op *extent_op;
2603         int ret;
2604
2605         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2606         if (!extent_op)
2607                 return -ENOMEM;
2608
2609         extent_op->flags_to_set = flags;
2610         extent_op->update_flags = 1;
2611         extent_op->update_key = 0;
2612         extent_op->is_data = is_data ? 1 : 0;
2613
2614         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2615                                           num_bytes, extent_op);
2616         if (ret)
2617                 kfree(extent_op);
2618         return ret;
2619 }
2620
2621 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2622                                       struct btrfs_root *root,
2623                                       struct btrfs_path *path,
2624                                       u64 objectid, u64 offset, u64 bytenr)
2625 {
2626         struct btrfs_delayed_ref_head *head;
2627         struct btrfs_delayed_ref_node *ref;
2628         struct btrfs_delayed_data_ref *data_ref;
2629         struct btrfs_delayed_ref_root *delayed_refs;
2630         struct rb_node *node;
2631         int ret = 0;
2632
2633         ret = -ENOENT;
2634         delayed_refs = &trans->transaction->delayed_refs;
2635         spin_lock(&delayed_refs->lock);
2636         head = btrfs_find_delayed_ref_head(trans, bytenr);
2637         if (!head)
2638                 goto out;
2639
2640         if (!mutex_trylock(&head->mutex)) {
2641                 atomic_inc(&head->node.refs);
2642                 spin_unlock(&delayed_refs->lock);
2643
2644                 btrfs_release_path(path);
2645
2646                 /*
2647                  * Mutex was contended, block until it's released and let
2648                  * caller try again
2649                  */
2650                 mutex_lock(&head->mutex);
2651                 mutex_unlock(&head->mutex);
2652                 btrfs_put_delayed_ref(&head->node);
2653                 return -EAGAIN;
2654         }
2655
2656         node = rb_prev(&head->node.rb_node);
2657         if (!node)
2658                 goto out_unlock;
2659
2660         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2661
2662         if (ref->bytenr != bytenr)
2663                 goto out_unlock;
2664
2665         ret = 1;
2666         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2667                 goto out_unlock;
2668
2669         data_ref = btrfs_delayed_node_to_data_ref(ref);
2670
2671         node = rb_prev(node);
2672         if (node) {
2673                 int seq = ref->seq;
2674
2675                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2676                 if (ref->bytenr == bytenr && ref->seq == seq)
2677                         goto out_unlock;
2678         }
2679
2680         if (data_ref->root != root->root_key.objectid ||
2681             data_ref->objectid != objectid || data_ref->offset != offset)
2682                 goto out_unlock;
2683
2684         ret = 0;
2685 out_unlock:
2686         mutex_unlock(&head->mutex);
2687 out:
2688         spin_unlock(&delayed_refs->lock);
2689         return ret;
2690 }
2691
2692 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2693                                         struct btrfs_root *root,
2694                                         struct btrfs_path *path,
2695                                         u64 objectid, u64 offset, u64 bytenr)
2696 {
2697         struct btrfs_root *extent_root = root->fs_info->extent_root;
2698         struct extent_buffer *leaf;
2699         struct btrfs_extent_data_ref *ref;
2700         struct btrfs_extent_inline_ref *iref;
2701         struct btrfs_extent_item *ei;
2702         struct btrfs_key key;
2703         u32 item_size;
2704         int ret;
2705
2706         key.objectid = bytenr;
2707         key.offset = (u64)-1;
2708         key.type = BTRFS_EXTENT_ITEM_KEY;
2709
2710         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2711         if (ret < 0)
2712                 goto out;
2713         BUG_ON(ret == 0); /* Corruption */
2714
2715         ret = -ENOENT;
2716         if (path->slots[0] == 0)
2717                 goto out;
2718
2719         path->slots[0]--;
2720         leaf = path->nodes[0];
2721         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2722
2723         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2724                 goto out;
2725
2726         ret = 1;
2727         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2728 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2729         if (item_size < sizeof(*ei)) {
2730                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2731                 goto out;
2732         }
2733 #endif
2734         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2735
2736         if (item_size != sizeof(*ei) +
2737             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2738                 goto out;
2739
2740         if (btrfs_extent_generation(leaf, ei) <=
2741             btrfs_root_last_snapshot(&root->root_item))
2742                 goto out;
2743
2744         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2745         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2746             BTRFS_EXTENT_DATA_REF_KEY)
2747                 goto out;
2748
2749         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2750         if (btrfs_extent_refs(leaf, ei) !=
2751             btrfs_extent_data_ref_count(leaf, ref) ||
2752             btrfs_extent_data_ref_root(leaf, ref) !=
2753             root->root_key.objectid ||
2754             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2755             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2756                 goto out;
2757
2758         ret = 0;
2759 out:
2760         return ret;
2761 }
2762
2763 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2764                           struct btrfs_root *root,
2765                           u64 objectid, u64 offset, u64 bytenr)
2766 {
2767         struct btrfs_path *path;
2768         int ret;
2769         int ret2;
2770
2771         path = btrfs_alloc_path();
2772         if (!path)
2773                 return -ENOENT;
2774
2775         do {
2776                 ret = check_committed_ref(trans, root, path, objectid,
2777                                           offset, bytenr);
2778                 if (ret && ret != -ENOENT)
2779                         goto out;
2780
2781                 ret2 = check_delayed_ref(trans, root, path, objectid,
2782                                          offset, bytenr);
2783         } while (ret2 == -EAGAIN);
2784
2785         if (ret2 && ret2 != -ENOENT) {
2786                 ret = ret2;
2787                 goto out;
2788         }
2789
2790         if (ret != -ENOENT || ret2 != -ENOENT)
2791                 ret = 0;
2792 out:
2793         btrfs_free_path(path);
2794         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2795                 WARN_ON(ret > 0);
2796         return ret;
2797 }
2798
2799 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2800                            struct btrfs_root *root,
2801                            struct extent_buffer *buf,
2802                            int full_backref, int inc, int for_cow)
2803 {
2804         u64 bytenr;
2805         u64 num_bytes;
2806         u64 parent;
2807         u64 ref_root;
2808         u32 nritems;
2809         struct btrfs_key key;
2810         struct btrfs_file_extent_item *fi;
2811         int i;
2812         int level;
2813         int ret = 0;
2814         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2815                             u64, u64, u64, u64, u64, u64, int);
2816
2817         ref_root = btrfs_header_owner(buf);
2818         nritems = btrfs_header_nritems(buf);
2819         level = btrfs_header_level(buf);
2820
2821         if (!root->ref_cows && level == 0)
2822                 return 0;
2823
2824         if (inc)
2825                 process_func = btrfs_inc_extent_ref;
2826         else
2827                 process_func = btrfs_free_extent;
2828
2829         if (full_backref)
2830                 parent = buf->start;
2831         else
2832                 parent = 0;
2833
2834         for (i = 0; i < nritems; i++) {
2835                 if (level == 0) {
2836                         btrfs_item_key_to_cpu(buf, &key, i);
2837                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2838                                 continue;
2839                         fi = btrfs_item_ptr(buf, i,
2840                                             struct btrfs_file_extent_item);
2841                         if (btrfs_file_extent_type(buf, fi) ==
2842                             BTRFS_FILE_EXTENT_INLINE)
2843                                 continue;
2844                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2845                         if (bytenr == 0)
2846                                 continue;
2847
2848                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2849                         key.offset -= btrfs_file_extent_offset(buf, fi);
2850                         ret = process_func(trans, root, bytenr, num_bytes,
2851                                            parent, ref_root, key.objectid,
2852                                            key.offset, for_cow);
2853                         if (ret)
2854                                 goto fail;
2855                 } else {
2856                         bytenr = btrfs_node_blockptr(buf, i);
2857                         num_bytes = btrfs_level_size(root, level - 1);
2858                         ret = process_func(trans, root, bytenr, num_bytes,
2859                                            parent, ref_root, level - 1, 0,
2860                                            for_cow);
2861                         if (ret)
2862                                 goto fail;
2863                 }
2864         }
2865         return 0;
2866 fail:
2867         return ret;
2868 }
2869
2870 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2871                   struct extent_buffer *buf, int full_backref, int for_cow)
2872 {
2873         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2874 }
2875
2876 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2877                   struct extent_buffer *buf, int full_backref, int for_cow)
2878 {
2879         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2880 }
2881
2882 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2883                                  struct btrfs_root *root,
2884                                  struct btrfs_path *path,
2885                                  struct btrfs_block_group_cache *cache)
2886 {
2887         int ret;
2888         struct btrfs_root *extent_root = root->fs_info->extent_root;
2889         unsigned long bi;
2890         struct extent_buffer *leaf;
2891
2892         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2893         if (ret < 0)
2894                 goto fail;
2895         BUG_ON(ret); /* Corruption */
2896
2897         leaf = path->nodes[0];
2898         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2899         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2900         btrfs_mark_buffer_dirty(leaf);
2901         btrfs_release_path(path);
2902 fail:
2903         if (ret) {
2904                 btrfs_abort_transaction(trans, root, ret);
2905                 return ret;
2906         }
2907         return 0;
2908
2909 }
2910
2911 static struct btrfs_block_group_cache *
2912 next_block_group(struct btrfs_root *root,
2913                  struct btrfs_block_group_cache *cache)
2914 {
2915         struct rb_node *node;
2916         spin_lock(&root->fs_info->block_group_cache_lock);
2917         node = rb_next(&cache->cache_node);
2918         btrfs_put_block_group(cache);
2919         if (node) {
2920                 cache = rb_entry(node, struct btrfs_block_group_cache,
2921                                  cache_node);
2922                 btrfs_get_block_group(cache);
2923         } else
2924                 cache = NULL;
2925         spin_unlock(&root->fs_info->block_group_cache_lock);
2926         return cache;
2927 }
2928
2929 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2930                             struct btrfs_trans_handle *trans,
2931                             struct btrfs_path *path)
2932 {
2933         struct btrfs_root *root = block_group->fs_info->tree_root;
2934         struct inode *inode = NULL;
2935         u64 alloc_hint = 0;
2936         int dcs = BTRFS_DC_ERROR;
2937         int num_pages = 0;
2938         int retries = 0;
2939         int ret = 0;
2940
2941         /*
2942          * If this block group is smaller than 100 megs don't bother caching the
2943          * block group.
2944          */
2945         if (block_group->key.offset < (100 * 1024 * 1024)) {
2946                 spin_lock(&block_group->lock);
2947                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2948                 spin_unlock(&block_group->lock);
2949                 return 0;
2950         }
2951
2952 again:
2953         inode = lookup_free_space_inode(root, block_group, path);
2954         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2955                 ret = PTR_ERR(inode);
2956                 btrfs_release_path(path);
2957                 goto out;
2958         }
2959
2960         if (IS_ERR(inode)) {
2961                 BUG_ON(retries);
2962                 retries++;
2963
2964                 if (block_group->ro)
2965                         goto out_free;
2966
2967                 ret = create_free_space_inode(root, trans, block_group, path);
2968                 if (ret)
2969                         goto out_free;
2970                 goto again;
2971         }
2972
2973         /* We've already setup this transaction, go ahead and exit */
2974         if (block_group->cache_generation == trans->transid &&
2975             i_size_read(inode)) {
2976                 dcs = BTRFS_DC_SETUP;
2977                 goto out_put;
2978         }
2979
2980         /*
2981          * We want to set the generation to 0, that way if anything goes wrong
2982          * from here on out we know not to trust this cache when we load up next
2983          * time.
2984          */
2985         BTRFS_I(inode)->generation = 0;
2986         ret = btrfs_update_inode(trans, root, inode);
2987         WARN_ON(ret);
2988
2989         if (i_size_read(inode) > 0) {
2990                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2991                                                       inode);
2992                 if (ret)
2993                         goto out_put;
2994         }
2995
2996         spin_lock(&block_group->lock);
2997         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2998             !btrfs_test_opt(root, SPACE_CACHE)) {
2999                 /*
3000                  * don't bother trying to write stuff out _if_
3001                  * a) we're not cached,
3002                  * b) we're with nospace_cache mount option.
3003                  */
3004                 dcs = BTRFS_DC_WRITTEN;
3005                 spin_unlock(&block_group->lock);
3006                 goto out_put;
3007         }
3008         spin_unlock(&block_group->lock);
3009
3010         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
3011         if (!num_pages)
3012                 num_pages = 1;
3013
3014         /*
3015          * Just to make absolutely sure we have enough space, we're going to
3016          * preallocate 12 pages worth of space for each block group.  In
3017          * practice we ought to use at most 8, but we need extra space so we can
3018          * add our header and have a terminator between the extents and the
3019          * bitmaps.
3020          */
3021         num_pages *= 16;
3022         num_pages *= PAGE_CACHE_SIZE;
3023
3024         ret = btrfs_check_data_free_space(inode, num_pages);
3025         if (ret)
3026                 goto out_put;
3027
3028         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3029                                               num_pages, num_pages,
3030                                               &alloc_hint);
3031         if (!ret)
3032                 dcs = BTRFS_DC_SETUP;
3033         btrfs_free_reserved_data_space(inode, num_pages);
3034
3035 out_put:
3036         iput(inode);
3037 out_free:
3038         btrfs_release_path(path);
3039 out:
3040         spin_lock(&block_group->lock);
3041         if (!ret && dcs == BTRFS_DC_SETUP)
3042                 block_group->cache_generation = trans->transid;
3043         block_group->disk_cache_state = dcs;
3044         spin_unlock(&block_group->lock);
3045
3046         return ret;
3047 }
3048
3049 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3050                                    struct btrfs_root *root)
3051 {
3052         struct btrfs_block_group_cache *cache;
3053         int err = 0;
3054         struct btrfs_path *path;
3055         u64 last = 0;
3056
3057         path = btrfs_alloc_path();
3058         if (!path)
3059                 return -ENOMEM;
3060
3061 again:
3062         while (1) {
3063                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3064                 while (cache) {
3065                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3066                                 break;
3067                         cache = next_block_group(root, cache);
3068                 }
3069                 if (!cache) {
3070                         if (last == 0)
3071                                 break;
3072                         last = 0;
3073                         continue;
3074                 }
3075                 err = cache_save_setup(cache, trans, path);
3076                 last = cache->key.objectid + cache->key.offset;
3077                 btrfs_put_block_group(cache);
3078         }
3079
3080         while (1) {
3081                 if (last == 0) {
3082                         err = btrfs_run_delayed_refs(trans, root,
3083                                                      (unsigned long)-1);
3084                         if (err) /* File system offline */
3085                                 goto out;
3086                 }
3087
3088                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3089                 while (cache) {
3090                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3091                                 btrfs_put_block_group(cache);
3092                                 goto again;
3093                         }
3094
3095                         if (cache->dirty)
3096                                 break;
3097                         cache = next_block_group(root, cache);
3098                 }
3099                 if (!cache) {
3100                         if (last == 0)
3101                                 break;
3102                         last = 0;
3103                         continue;
3104                 }
3105
3106                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3107                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3108                 cache->dirty = 0;
3109                 last = cache->key.objectid + cache->key.offset;
3110
3111                 err = write_one_cache_group(trans, root, path, cache);
3112                 if (err) /* File system offline */
3113                         goto out;
3114
3115                 btrfs_put_block_group(cache);
3116         }
3117
3118         while (1) {
3119                 /*
3120                  * I don't think this is needed since we're just marking our
3121                  * preallocated extent as written, but just in case it can't
3122                  * hurt.
3123                  */
3124                 if (last == 0) {
3125                         err = btrfs_run_delayed_refs(trans, root,
3126                                                      (unsigned long)-1);
3127                         if (err) /* File system offline */
3128                                 goto out;
3129                 }
3130
3131                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3132                 while (cache) {
3133                         /*
3134                          * Really this shouldn't happen, but it could if we
3135                          * couldn't write the entire preallocated extent and
3136                          * splitting the extent resulted in a new block.
3137                          */
3138                         if (cache->dirty) {
3139                                 btrfs_put_block_group(cache);
3140                                 goto again;
3141                         }
3142                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3143                                 break;
3144                         cache = next_block_group(root, cache);
3145                 }
3146                 if (!cache) {
3147                         if (last == 0)
3148                                 break;
3149                         last = 0;
3150                         continue;
3151                 }
3152
3153                 err = btrfs_write_out_cache(root, trans, cache, path);
3154
3155                 /*
3156                  * If we didn't have an error then the cache state is still
3157                  * NEED_WRITE, so we can set it to WRITTEN.
3158                  */
3159                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3160                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3161                 last = cache->key.objectid + cache->key.offset;
3162                 btrfs_put_block_group(cache);
3163         }
3164 out:
3165
3166         btrfs_free_path(path);
3167         return err;
3168 }
3169
3170 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3171 {
3172         struct btrfs_block_group_cache *block_group;
3173         int readonly = 0;
3174
3175         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3176         if (!block_group || block_group->ro)
3177                 readonly = 1;
3178         if (block_group)
3179                 btrfs_put_block_group(block_group);
3180         return readonly;
3181 }
3182
3183 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3184                              u64 total_bytes, u64 bytes_used,
3185                              struct btrfs_space_info **space_info)
3186 {
3187         struct btrfs_space_info *found;
3188         int i;
3189         int factor;
3190
3191         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3192                      BTRFS_BLOCK_GROUP_RAID10))
3193                 factor = 2;
3194         else
3195                 factor = 1;
3196
3197         found = __find_space_info(info, flags);
3198         if (found) {
3199                 spin_lock(&found->lock);
3200                 found->total_bytes += total_bytes;
3201                 found->disk_total += total_bytes * factor;
3202                 found->bytes_used += bytes_used;
3203                 found->disk_used += bytes_used * factor;
3204                 found->full = 0;
3205                 spin_unlock(&found->lock);
3206                 *space_info = found;
3207                 return 0;
3208         }
3209         found = kzalloc(sizeof(*found), GFP_NOFS);
3210         if (!found)
3211                 return -ENOMEM;
3212
3213         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3214                 INIT_LIST_HEAD(&found->block_groups[i]);
3215         init_rwsem(&found->groups_sem);
3216         spin_lock_init(&found->lock);
3217         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3218         found->total_bytes = total_bytes;
3219         found->disk_total = total_bytes * factor;
3220         found->bytes_used = bytes_used;
3221         found->disk_used = bytes_used * factor;
3222         found->bytes_pinned = 0;
3223         found->bytes_reserved = 0;
3224         found->bytes_readonly = 0;
3225         found->bytes_may_use = 0;
3226         found->full = 0;
3227         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3228         found->chunk_alloc = 0;
3229         found->flush = 0;
3230         init_waitqueue_head(&found->wait);
3231         *space_info = found;
3232         list_add_rcu(&found->list, &info->space_info);
3233         if (flags & BTRFS_BLOCK_GROUP_DATA)
3234                 info->data_sinfo = found;
3235         return 0;
3236 }
3237
3238 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3239 {
3240         u64 extra_flags = chunk_to_extended(flags) &
3241                                 BTRFS_EXTENDED_PROFILE_MASK;
3242
3243         if (flags & BTRFS_BLOCK_GROUP_DATA)
3244                 fs_info->avail_data_alloc_bits |= extra_flags;
3245         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3246                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3247         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3248                 fs_info->avail_system_alloc_bits |= extra_flags;
3249 }
3250
3251 /*
3252  * returns target flags in extended format or 0 if restripe for this
3253  * chunk_type is not in progress
3254  *
3255  * should be called with either volume_mutex or balance_lock held
3256  */
3257 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3258 {
3259         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3260         u64 target = 0;
3261
3262         if (!bctl)
3263                 return 0;
3264
3265         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3266             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3267                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3268         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3269                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3270                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3271         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3272                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3273                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3274         }
3275
3276         return target;
3277 }
3278
3279 /*
3280  * @flags: available profiles in extended format (see ctree.h)
3281  *
3282  * Returns reduced profile in chunk format.  If profile changing is in
3283  * progress (either running or paused) picks the target profile (if it's
3284  * already available), otherwise falls back to plain reducing.
3285  */
3286 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3287 {
3288         /*
3289          * we add in the count of missing devices because we want
3290          * to make sure that any RAID levels on a degraded FS
3291          * continue to be honored.
3292          */
3293         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3294                 root->fs_info->fs_devices->missing_devices;
3295         u64 target;
3296
3297         /*
3298          * see if restripe for this chunk_type is in progress, if so
3299          * try to reduce to the target profile
3300          */
3301         spin_lock(&root->fs_info->balance_lock);
3302         target = get_restripe_target(root->fs_info, flags);
3303         if (target) {
3304                 /* pick target profile only if it's already available */
3305                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3306                         spin_unlock(&root->fs_info->balance_lock);
3307                         return extended_to_chunk(target);
3308                 }
3309         }
3310         spin_unlock(&root->fs_info->balance_lock);
3311
3312         if (num_devices == 1)
3313                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3314         if (num_devices < 4)
3315                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3316
3317         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3318             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3319                       BTRFS_BLOCK_GROUP_RAID10))) {
3320                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3321         }
3322
3323         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3324             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3325                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3326         }
3327
3328         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3329             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3330              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3331              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3332                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3333         }
3334
3335         return extended_to_chunk(flags);
3336 }
3337
3338 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3339 {
3340         if (flags & BTRFS_BLOCK_GROUP_DATA)
3341                 flags |= root->fs_info->avail_data_alloc_bits;
3342         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3343                 flags |= root->fs_info->avail_system_alloc_bits;
3344         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3345                 flags |= root->fs_info->avail_metadata_alloc_bits;
3346
3347         return btrfs_reduce_alloc_profile(root, flags);
3348 }
3349
3350 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3351 {
3352         u64 flags;
3353
3354         if (data)
3355                 flags = BTRFS_BLOCK_GROUP_DATA;
3356         else if (root == root->fs_info->chunk_root)
3357                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3358         else
3359                 flags = BTRFS_BLOCK_GROUP_METADATA;
3360
3361         return get_alloc_profile(root, flags);
3362 }
3363
3364 /*
3365  * This will check the space that the inode allocates from to make sure we have
3366  * enough space for bytes.
3367  */
3368 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3369 {
3370         struct btrfs_space_info *data_sinfo;
3371         struct btrfs_root *root = BTRFS_I(inode)->root;
3372         struct btrfs_fs_info *fs_info = root->fs_info;
3373         u64 used;
3374         int ret = 0, committed = 0, alloc_chunk = 1;
3375
3376         /* make sure bytes are sectorsize aligned */
3377         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3378
3379         if (root == root->fs_info->tree_root ||
3380             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3381                 alloc_chunk = 0;
3382                 committed = 1;
3383         }
3384
3385         data_sinfo = fs_info->data_sinfo;
3386         if (!data_sinfo)
3387                 goto alloc;
3388
3389 again:
3390         /* make sure we have enough space to handle the data first */
3391         spin_lock(&data_sinfo->lock);
3392         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3393                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3394                 data_sinfo->bytes_may_use;
3395
3396         if (used + bytes > data_sinfo->total_bytes) {
3397                 struct btrfs_trans_handle *trans;
3398
3399                 /*
3400                  * if we don't have enough free bytes in this space then we need
3401                  * to alloc a new chunk.
3402                  */
3403                 if (!data_sinfo->full && alloc_chunk) {
3404                         u64 alloc_target;
3405
3406                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3407                         spin_unlock(&data_sinfo->lock);
3408 alloc:
3409                         alloc_target = btrfs_get_alloc_profile(root, 1);
3410                         trans = btrfs_join_transaction(root);
3411                         if (IS_ERR(trans))
3412                                 return PTR_ERR(trans);
3413
3414                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3415                                              bytes + 2 * 1024 * 1024,
3416                                              alloc_target,
3417                                              CHUNK_ALLOC_NO_FORCE);
3418                         btrfs_end_transaction(trans, root);
3419                         if (ret < 0) {
3420                                 if (ret != -ENOSPC)
3421                                         return ret;
3422                                 else
3423                                         goto commit_trans;
3424                         }
3425
3426                         if (!data_sinfo)
3427                                 data_sinfo = fs_info->data_sinfo;
3428
3429                         goto again;
3430                 }
3431
3432                 /*
3433                  * If we have less pinned bytes than we want to allocate then
3434                  * don't bother committing the transaction, it won't help us.
3435                  */
3436                 if (data_sinfo->bytes_pinned < bytes)
3437                         committed = 1;
3438                 spin_unlock(&data_sinfo->lock);
3439
3440                 /* commit the current transaction and try again */
3441 commit_trans:
3442                 if (!committed &&
3443                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3444                         committed = 1;
3445                         trans = btrfs_join_transaction(root);
3446                         if (IS_ERR(trans))
3447                                 return PTR_ERR(trans);
3448                         ret = btrfs_commit_transaction(trans, root);
3449                         if (ret)
3450                                 return ret;
3451                         goto again;
3452                 }
3453
3454                 return -ENOSPC;
3455         }
3456         data_sinfo->bytes_may_use += bytes;
3457         trace_btrfs_space_reservation(root->fs_info, "space_info",
3458                                       data_sinfo->flags, bytes, 1);
3459         spin_unlock(&data_sinfo->lock);
3460
3461         return 0;
3462 }
3463
3464 /*
3465  * Called if we need to clear a data reservation for this inode.
3466  */
3467 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3468 {
3469         struct btrfs_root *root = BTRFS_I(inode)->root;
3470         struct btrfs_space_info *data_sinfo;
3471
3472         /* make sure bytes are sectorsize aligned */
3473         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3474
3475         data_sinfo = root->fs_info->data_sinfo;
3476         spin_lock(&data_sinfo->lock);
3477         data_sinfo->bytes_may_use -= bytes;
3478         trace_btrfs_space_reservation(root->fs_info, "space_info",
3479                                       data_sinfo->flags, bytes, 0);
3480         spin_unlock(&data_sinfo->lock);
3481 }
3482
3483 static void force_metadata_allocation(struct btrfs_fs_info *info)
3484 {
3485         struct list_head *head = &info->space_info;
3486         struct btrfs_space_info *found;
3487
3488         rcu_read_lock();
3489         list_for_each_entry_rcu(found, head, list) {
3490                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3491                         found->force_alloc = CHUNK_ALLOC_FORCE;
3492         }
3493         rcu_read_unlock();
3494 }
3495
3496 static int should_alloc_chunk(struct btrfs_root *root,
3497                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3498                               int force)
3499 {
3500         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3501         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3502         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3503         u64 thresh;
3504
3505         if (force == CHUNK_ALLOC_FORCE)
3506                 return 1;
3507
3508         /*
3509          * We need to take into account the global rsv because for all intents
3510          * and purposes it's used space.  Don't worry about locking the
3511          * global_rsv, it doesn't change except when the transaction commits.
3512          */
3513         num_allocated += global_rsv->size;
3514
3515         /*
3516          * in limited mode, we want to have some free space up to
3517          * about 1% of the FS size.
3518          */
3519         if (force == CHUNK_ALLOC_LIMITED) {
3520                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3521                 thresh = max_t(u64, 64 * 1024 * 1024,
3522                                div_factor_fine(thresh, 1));
3523
3524                 if (num_bytes - num_allocated < thresh)
3525                         return 1;
3526         }
3527         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3528
3529         /* 256MB or 2% of the FS */
3530         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3531         /* system chunks need a much small threshold */
3532         if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
3533                 thresh = 32 * 1024 * 1024;
3534
3535         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3536                 return 0;
3537         return 1;
3538 }
3539
3540 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3541 {
3542         u64 num_dev;
3543
3544         if (type & BTRFS_BLOCK_GROUP_RAID10 ||
3545             type & BTRFS_BLOCK_GROUP_RAID0)
3546                 num_dev = root->fs_info->fs_devices->rw_devices;
3547         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3548                 num_dev = 2;
3549         else
3550                 num_dev = 1;    /* DUP or single */
3551
3552         /* metadata for updaing devices and chunk tree */
3553         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3554 }
3555
3556 static void check_system_chunk(struct btrfs_trans_handle *trans,
3557                                struct btrfs_root *root, u64 type)
3558 {
3559         struct btrfs_space_info *info;
3560         u64 left;
3561         u64 thresh;
3562
3563         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3564         spin_lock(&info->lock);
3565         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3566                 info->bytes_reserved - info->bytes_readonly;
3567         spin_unlock(&info->lock);
3568
3569         thresh = get_system_chunk_thresh(root, type);
3570         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3571                 printk(KERN_INFO "left=%llu, need=%llu, flags=%llu\n",
3572                        left, thresh, type);
3573                 dump_space_info(info, 0, 0);
3574         }
3575
3576         if (left < thresh) {
3577                 u64 flags;
3578
3579                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3580                 btrfs_alloc_chunk(trans, root, flags);
3581         }
3582 }
3583
3584 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3585                           struct btrfs_root *extent_root, u64 alloc_bytes,
3586                           u64 flags, int force)
3587 {
3588         struct btrfs_space_info *space_info;
3589         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3590         int wait_for_alloc = 0;
3591         int ret = 0;
3592
3593         space_info = __find_space_info(extent_root->fs_info, flags);
3594         if (!space_info) {
3595                 ret = update_space_info(extent_root->fs_info, flags,
3596                                         0, 0, &space_info);
3597                 BUG_ON(ret); /* -ENOMEM */
3598         }
3599         BUG_ON(!space_info); /* Logic error */
3600
3601 again:
3602         spin_lock(&space_info->lock);
3603         if (force < space_info->force_alloc)
3604                 force = space_info->force_alloc;
3605         if (space_info->full) {
3606                 spin_unlock(&space_info->lock);
3607                 return 0;
3608         }
3609
3610         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3611                 spin_unlock(&space_info->lock);
3612                 return 0;
3613         } else if (space_info->chunk_alloc) {
3614                 wait_for_alloc = 1;
3615         } else {
3616                 space_info->chunk_alloc = 1;
3617         }
3618
3619         spin_unlock(&space_info->lock);
3620
3621         mutex_lock(&fs_info->chunk_mutex);
3622
3623         /*
3624          * The chunk_mutex is held throughout the entirety of a chunk
3625          * allocation, so once we've acquired the chunk_mutex we know that the
3626          * other guy is done and we need to recheck and see if we should
3627          * allocate.
3628          */
3629         if (wait_for_alloc) {
3630                 mutex_unlock(&fs_info->chunk_mutex);
3631                 wait_for_alloc = 0;
3632                 goto again;
3633         }
3634
3635         /*
3636          * If we have mixed data/metadata chunks we want to make sure we keep
3637          * allocating mixed chunks instead of individual chunks.
3638          */
3639         if (btrfs_mixed_space_info(space_info))
3640                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3641
3642         /*
3643          * if we're doing a data chunk, go ahead and make sure that
3644          * we keep a reasonable number of metadata chunks allocated in the
3645          * FS as well.
3646          */
3647         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3648                 fs_info->data_chunk_allocations++;
3649                 if (!(fs_info->data_chunk_allocations %
3650                       fs_info->metadata_ratio))
3651                         force_metadata_allocation(fs_info);
3652         }
3653
3654         /*
3655          * Check if we have enough space in SYSTEM chunk because we may need
3656          * to update devices.
3657          */
3658         check_system_chunk(trans, extent_root, flags);
3659
3660         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3661         if (ret < 0 && ret != -ENOSPC)
3662                 goto out;
3663
3664         spin_lock(&space_info->lock);
3665         if (ret)
3666                 space_info->full = 1;
3667         else
3668                 ret = 1;
3669
3670         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3671         space_info->chunk_alloc = 0;
3672         spin_unlock(&space_info->lock);
3673 out:
3674         mutex_unlock(&fs_info->chunk_mutex);
3675         return ret;
3676 }
3677
3678 /*
3679  * shrink metadata reservation for delalloc
3680  */
3681 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3682                             bool wait_ordered)
3683 {
3684         struct btrfs_block_rsv *block_rsv;
3685         struct btrfs_space_info *space_info;
3686         struct btrfs_trans_handle *trans;
3687         u64 delalloc_bytes;
3688         u64 max_reclaim;
3689         long time_left;
3690         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3691         int loops = 0;
3692
3693         trans = (struct btrfs_trans_handle *)current->journal_info;
3694         block_rsv = &root->fs_info->delalloc_block_rsv;
3695         space_info = block_rsv->space_info;
3696
3697         smp_mb();
3698         delalloc_bytes = root->fs_info->delalloc_bytes;
3699         if (delalloc_bytes == 0) {
3700                 if (trans)
3701                         return;
3702                 btrfs_wait_ordered_extents(root, 0, 0);
3703                 return;
3704         }
3705
3706         while (delalloc_bytes && loops < 3) {
3707                 max_reclaim = min(delalloc_bytes, to_reclaim);
3708                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3709                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3710                                                WB_REASON_FS_FREE_SPACE);
3711
3712                 spin_lock(&space_info->lock);
3713                 if (space_info->bytes_used + space_info->bytes_reserved +
3714                     space_info->bytes_pinned + space_info->bytes_readonly +
3715                     space_info->bytes_may_use + orig <=
3716                     space_info->total_bytes) {
3717                         spin_unlock(&space_info->lock);
3718                         break;
3719                 }
3720                 spin_unlock(&space_info->lock);
3721
3722                 loops++;
3723                 if (wait_ordered && !trans) {
3724                         btrfs_wait_ordered_extents(root, 0, 0);
3725                 } else {
3726                         time_left = schedule_timeout_killable(1);
3727                         if (time_left)
3728                                 break;
3729                 }
3730                 smp_mb();
3731                 delalloc_bytes = root->fs_info->delalloc_bytes;
3732         }
3733 }
3734
3735 /**
3736  * maybe_commit_transaction - possibly commit the transaction if its ok to
3737  * @root - the root we're allocating for
3738  * @bytes - the number of bytes we want to reserve
3739  * @force - force the commit
3740  *
3741  * This will check to make sure that committing the transaction will actually
3742  * get us somewhere and then commit the transaction if it does.  Otherwise it
3743  * will return -ENOSPC.
3744  */
3745 static int may_commit_transaction(struct btrfs_root *root,
3746                                   struct btrfs_space_info *space_info,
3747                                   u64 bytes, int force)
3748 {
3749         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3750         struct btrfs_trans_handle *trans;
3751
3752         trans = (struct btrfs_trans_handle *)current->journal_info;
3753         if (trans)
3754                 return -EAGAIN;
3755
3756         if (force)
3757                 goto commit;
3758
3759         /* See if there is enough pinned space to make this reservation */
3760         spin_lock(&space_info->lock);
3761         if (space_info->bytes_pinned >= bytes) {
3762                 spin_unlock(&space_info->lock);
3763                 goto commit;
3764         }
3765         spin_unlock(&space_info->lock);
3766
3767         /*
3768          * See if there is some space in the delayed insertion reservation for
3769          * this reservation.
3770          */
3771         if (space_info != delayed_rsv->space_info)
3772                 return -ENOSPC;
3773
3774         spin_lock(&space_info->lock);
3775         spin_lock(&delayed_rsv->lock);
3776         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3777                 spin_unlock(&delayed_rsv->lock);
3778                 spin_unlock(&space_info->lock);
3779                 return -ENOSPC;
3780         }
3781         spin_unlock(&delayed_rsv->lock);
3782         spin_unlock(&space_info->lock);
3783
3784 commit:
3785         trans = btrfs_join_transaction(root);
3786         if (IS_ERR(trans))
3787                 return -ENOSPC;
3788
3789         return btrfs_commit_transaction(trans, root);
3790 }
3791
3792 enum flush_state {
3793         FLUSH_DELALLOC          =       1,
3794         FLUSH_DELALLOC_WAIT     =       2,
3795         FLUSH_DELAYED_ITEMS_NR  =       3,
3796         FLUSH_DELAYED_ITEMS     =       4,
3797         COMMIT_TRANS            =       5,
3798 };
3799
3800 static int flush_space(struct btrfs_root *root,
3801                        struct btrfs_space_info *space_info, u64 num_bytes,
3802                        u64 orig_bytes, int state)
3803 {
3804         struct btrfs_trans_handle *trans;
3805         int nr;
3806         int ret = 0;
3807
3808         switch (state) {
3809         case FLUSH_DELALLOC:
3810         case FLUSH_DELALLOC_WAIT:
3811                 shrink_delalloc(root, num_bytes, orig_bytes,
3812                                 state == FLUSH_DELALLOC_WAIT);
3813                 break;
3814         case FLUSH_DELAYED_ITEMS_NR:
3815         case FLUSH_DELAYED_ITEMS:
3816                 if (state == FLUSH_DELAYED_ITEMS_NR) {
3817                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
3818
3819                         nr = (int)div64_u64(num_bytes, bytes);
3820                         if (!nr)
3821                                 nr = 1;
3822                         nr *= 2;
3823                 } else {
3824                         nr = -1;
3825                 }
3826                 trans = btrfs_join_transaction(root);
3827                 if (IS_ERR(trans)) {
3828                         ret = PTR_ERR(trans);
3829                         break;
3830                 }
3831                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
3832                 btrfs_end_transaction(trans, root);
3833                 break;
3834         case COMMIT_TRANS:
3835                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3836                 break;
3837         default:
3838                 ret = -ENOSPC;
3839                 break;
3840         }
3841
3842         return ret;
3843 }
3844 /**
3845  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3846  * @root - the root we're allocating for
3847  * @block_rsv - the block_rsv we're allocating for
3848  * @orig_bytes - the number of bytes we want
3849  * @flush - wether or not we can flush to make our reservation
3850  *
3851  * This will reserve orgi_bytes number of bytes from the space info associated
3852  * with the block_rsv.  If there is not enough space it will make an attempt to
3853  * flush out space to make room.  It will do this by flushing delalloc if
3854  * possible or committing the transaction.  If flush is 0 then no attempts to
3855  * regain reservations will be made and this will fail if there is not enough
3856  * space already.
3857  */
3858 static int reserve_metadata_bytes(struct btrfs_root *root,
3859                                   struct btrfs_block_rsv *block_rsv,
3860                                   u64 orig_bytes, int flush)
3861 {
3862         struct btrfs_space_info *space_info = block_rsv->space_info;
3863         u64 used;
3864         u64 num_bytes = orig_bytes;
3865         int flush_state = FLUSH_DELALLOC;
3866         int ret = 0;
3867         bool flushing = false;
3868         bool committed = false;
3869
3870 again:
3871         ret = 0;
3872         spin_lock(&space_info->lock);
3873         /*
3874          * We only want to wait if somebody other than us is flushing and we are
3875          * actually alloed to flush.
3876          */
3877         while (flush && !flushing && space_info->flush) {
3878                 spin_unlock(&space_info->lock);
3879                 /*
3880                  * If we have a trans handle we can't wait because the flusher
3881                  * may have to commit the transaction, which would mean we would
3882                  * deadlock since we are waiting for the flusher to finish, but
3883                  * hold the current transaction open.
3884                  */
3885                 if (current->journal_info)
3886                         return -EAGAIN;
3887                 ret = wait_event_killable(space_info->wait, !space_info->flush);
3888                 /* Must have been killed, return */
3889                 if (ret)
3890                         return -EINTR;
3891
3892                 spin_lock(&space_info->lock);
3893         }
3894
3895         ret = -ENOSPC;
3896         used = space_info->bytes_used + space_info->bytes_reserved +
3897                 space_info->bytes_pinned + space_info->bytes_readonly +
3898                 space_info->bytes_may_use;
3899
3900         /*
3901          * The idea here is that we've not already over-reserved the block group
3902          * then we can go ahead and save our reservation first and then start
3903          * flushing if we need to.  Otherwise if we've already overcommitted
3904          * lets start flushing stuff first and then come back and try to make
3905          * our reservation.
3906          */
3907         if (used <= space_info->total_bytes) {
3908                 if (used + orig_bytes <= space_info->total_bytes) {
3909                         space_info->bytes_may_use += orig_bytes;
3910                         trace_btrfs_space_reservation(root->fs_info,
3911                                 "space_info", space_info->flags, orig_bytes, 1);
3912                         ret = 0;
3913                 } else {
3914                         /*
3915                          * Ok set num_bytes to orig_bytes since we aren't
3916                          * overocmmitted, this way we only try and reclaim what
3917                          * we need.
3918                          */
3919                         num_bytes = orig_bytes;
3920                 }
3921         } else {
3922                 /*
3923                  * Ok we're over committed, set num_bytes to the overcommitted
3924                  * amount plus the amount of bytes that we need for this
3925                  * reservation.
3926                  */
3927                 num_bytes = used - space_info->total_bytes +
3928                         (orig_bytes * 2);
3929         }
3930
3931         if (ret) {
3932                 u64 profile = btrfs_get_alloc_profile(root, 0);
3933                 u64 avail;
3934
3935                 /*
3936                  * If we have a lot of space that's pinned, don't bother doing
3937                  * the overcommit dance yet and just commit the transaction.
3938                  */
3939                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3940                 do_div(avail, 10);
3941                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3942                         space_info->flush = 1;
3943                         flushing = true;
3944                         spin_unlock(&space_info->lock);
3945                         ret = may_commit_transaction(root, space_info,
3946                                                      orig_bytes, 1);
3947                         if (ret)
3948                                 goto out;
3949                         committed = true;
3950                         goto again;
3951                 }
3952
3953                 spin_lock(&root->fs_info->free_chunk_lock);
3954                 avail = root->fs_info->free_chunk_space;
3955
3956                 /*
3957                  * If we have dup, raid1 or raid10 then only half of the free
3958                  * space is actually useable.
3959                  */
3960                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3961                                BTRFS_BLOCK_GROUP_RAID1 |
3962                                BTRFS_BLOCK_GROUP_RAID10))
3963                         avail >>= 1;
3964
3965                 /*
3966                  * If we aren't flushing don't let us overcommit too much, say
3967                  * 1/8th of the space.  If we can flush, let it overcommit up to
3968                  * 1/2 of the space.
3969                  */
3970                 if (flush)
3971                         avail >>= 3;
3972                 else
3973                         avail >>= 1;
3974                  spin_unlock(&root->fs_info->free_chunk_lock);
3975
3976                 if (used + num_bytes < space_info->total_bytes + avail) {
3977                         space_info->bytes_may_use += orig_bytes;
3978                         trace_btrfs_space_reservation(root->fs_info,
3979                                 "space_info", space_info->flags, orig_bytes, 1);
3980                         ret = 0;
3981                 }
3982         }
3983
3984         /*
3985          * Couldn't make our reservation, save our place so while we're trying
3986          * to reclaim space we can actually use it instead of somebody else
3987          * stealing it from us.
3988          */
3989         if (ret && flush) {
3990                 flushing = true;
3991                 space_info->flush = 1;
3992         }
3993
3994         spin_unlock(&space_info->lock);
3995
3996         if (!ret || !flush)
3997                 goto out;
3998
3999         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4000                           flush_state);
4001         flush_state++;
4002         if (!ret)
4003                 goto again;
4004         else if (flush_state <= COMMIT_TRANS)
4005                 goto again;
4006
4007 out:
4008         if (flushing) {
4009                 spin_lock(&space_info->lock);
4010                 space_info->flush = 0;
4011                 wake_up_all(&space_info->wait);
4012                 spin_unlock(&space_info->lock);
4013         }
4014         return ret;
4015 }
4016
4017 static struct btrfs_block_rsv *get_block_rsv(
4018                                         const struct btrfs_trans_handle *trans,
4019                                         const struct btrfs_root *root)
4020 {
4021         struct btrfs_block_rsv *block_rsv = NULL;
4022
4023         if (root->ref_cows)
4024                 block_rsv = trans->block_rsv;
4025
4026         if (root == root->fs_info->csum_root && trans->adding_csums)
4027                 block_rsv = trans->block_rsv;
4028
4029         if (!block_rsv)
4030                 block_rsv = root->block_rsv;
4031
4032         if (!block_rsv)
4033                 block_rsv = &root->fs_info->empty_block_rsv;
4034
4035         return block_rsv;
4036 }
4037
4038 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4039                                u64 num_bytes)
4040 {
4041         int ret = -ENOSPC;
4042         spin_lock(&block_rsv->lock);
4043         if (block_rsv->reserved >= num_bytes) {
4044                 block_rsv->reserved -= num_bytes;
4045                 if (block_rsv->reserved < block_rsv->size)
4046                         block_rsv->full = 0;
4047                 ret = 0;
4048         }
4049         spin_unlock(&block_rsv->lock);
4050         return ret;
4051 }
4052
4053 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4054                                 u64 num_bytes, int update_size)
4055 {
4056         spin_lock(&block_rsv->lock);
4057         block_rsv->reserved += num_bytes;
4058         if (update_size)
4059                 block_rsv->size += num_bytes;
4060         else if (block_rsv->reserved >= block_rsv->size)
4061                 block_rsv->full = 1;
4062         spin_unlock(&block_rsv->lock);
4063 }
4064
4065 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4066                                     struct btrfs_block_rsv *block_rsv,
4067                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4068 {
4069         struct btrfs_space_info *space_info = block_rsv->space_info;
4070
4071         spin_lock(&block_rsv->lock);
4072         if (num_bytes == (u64)-1)
4073                 num_bytes = block_rsv->size;
4074         block_rsv->size -= num_bytes;
4075         if (block_rsv->reserved >= block_rsv->size) {
4076                 num_bytes = block_rsv->reserved - block_rsv->size;
4077                 block_rsv->reserved = block_rsv->size;
4078                 block_rsv->full = 1;
4079         } else {
4080                 num_bytes = 0;
4081         }
4082         spin_unlock(&block_rsv->lock);
4083
4084         if (num_bytes > 0) {
4085                 if (dest) {
4086                         spin_lock(&dest->lock);
4087                         if (!dest->full) {
4088                                 u64 bytes_to_add;
4089
4090                                 bytes_to_add = dest->size - dest->reserved;
4091                                 bytes_to_add = min(num_bytes, bytes_to_add);
4092                                 dest->reserved += bytes_to_add;
4093                                 if (dest->reserved >= dest->size)
4094                                         dest->full = 1;
4095                                 num_bytes -= bytes_to_add;
4096                         }
4097                         spin_unlock(&dest->lock);
4098                 }
4099                 if (num_bytes) {
4100                         spin_lock(&space_info->lock);
4101                         space_info->bytes_may_use -= num_bytes;
4102                         trace_btrfs_space_reservation(fs_info, "space_info",
4103                                         space_info->flags, num_bytes, 0);
4104                         space_info->reservation_progress++;
4105                         spin_unlock(&space_info->lock);
4106                 }
4107         }
4108 }
4109
4110 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4111                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4112 {
4113         int ret;
4114
4115         ret = block_rsv_use_bytes(src, num_bytes);
4116         if (ret)
4117                 return ret;
4118
4119         block_rsv_add_bytes(dst, num_bytes, 1);
4120         return 0;
4121 }
4122
4123 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
4124 {
4125         memset(rsv, 0, sizeof(*rsv));
4126         spin_lock_init(&rsv->lock);
4127 }
4128
4129 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
4130 {
4131         struct btrfs_block_rsv *block_rsv;
4132         struct btrfs_fs_info *fs_info = root->fs_info;
4133
4134         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4135         if (!block_rsv)
4136                 return NULL;
4137
4138         btrfs_init_block_rsv(block_rsv);
4139         block_rsv->space_info = __find_space_info(fs_info,
4140                                                   BTRFS_BLOCK_GROUP_METADATA);
4141         return block_rsv;
4142 }
4143
4144 void btrfs_free_block_rsv(struct btrfs_root *root,
4145                           struct btrfs_block_rsv *rsv)
4146 {
4147         btrfs_block_rsv_release(root, rsv, (u64)-1);
4148         kfree(rsv);
4149 }
4150
4151 static inline int __block_rsv_add(struct btrfs_root *root,
4152                                   struct btrfs_block_rsv *block_rsv,
4153                                   u64 num_bytes, int flush)
4154 {
4155         int ret;
4156
4157         if (num_bytes == 0)
4158                 return 0;
4159
4160         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4161         if (!ret) {
4162                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4163                 return 0;
4164         }
4165
4166         return ret;
4167 }
4168
4169 int btrfs_block_rsv_add(struct btrfs_root *root,
4170                         struct btrfs_block_rsv *block_rsv,
4171                         u64 num_bytes)
4172 {
4173         return __block_rsv_add(root, block_rsv, num_bytes, 1);
4174 }
4175
4176 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
4177                                 struct btrfs_block_rsv *block_rsv,
4178                                 u64 num_bytes)
4179 {
4180         return __block_rsv_add(root, block_rsv, num_bytes, 0);
4181 }
4182
4183 int btrfs_block_rsv_check(struct btrfs_root *root,
4184                           struct btrfs_block_rsv *block_rsv, int min_factor)
4185 {
4186         u64 num_bytes = 0;
4187         int ret = -ENOSPC;
4188
4189         if (!block_rsv)
4190                 return 0;
4191
4192         spin_lock(&block_rsv->lock);
4193         num_bytes = div_factor(block_rsv->size, min_factor);
4194         if (block_rsv->reserved >= num_bytes)
4195                 ret = 0;
4196         spin_unlock(&block_rsv->lock);
4197
4198         return ret;
4199 }
4200
4201 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4202                                            struct btrfs_block_rsv *block_rsv,
4203                                            u64 min_reserved, int flush)
4204 {
4205         u64 num_bytes = 0;
4206         int ret = -ENOSPC;
4207
4208         if (!block_rsv)
4209                 return 0;
4210
4211         spin_lock(&block_rsv->lock);
4212         num_bytes = min_reserved;
4213         if (block_rsv->reserved >= num_bytes)
4214                 ret = 0;
4215         else
4216                 num_bytes -= block_rsv->reserved;
4217         spin_unlock(&block_rsv->lock);
4218
4219         if (!ret)
4220                 return 0;
4221
4222         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4223         if (!ret) {
4224                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4225                 return 0;
4226         }
4227
4228         return ret;
4229 }
4230
4231 int btrfs_block_rsv_refill(struct btrfs_root *root,
4232                            struct btrfs_block_rsv *block_rsv,
4233                            u64 min_reserved)
4234 {
4235         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4236 }
4237
4238 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4239                                    struct btrfs_block_rsv *block_rsv,
4240                                    u64 min_reserved)
4241 {
4242         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4243 }
4244
4245 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4246                             struct btrfs_block_rsv *dst_rsv,
4247                             u64 num_bytes)
4248 {
4249         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4250 }
4251
4252 void btrfs_block_rsv_release(struct btrfs_root *root,
4253                              struct btrfs_block_rsv *block_rsv,
4254                              u64 num_bytes)
4255 {
4256         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4257         if (global_rsv->full || global_rsv == block_rsv ||
4258             block_rsv->space_info != global_rsv->space_info)
4259                 global_rsv = NULL;
4260         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4261                                 num_bytes);
4262 }
4263
4264 /*
4265  * helper to calculate size of global block reservation.
4266  * the desired value is sum of space used by extent tree,
4267  * checksum tree and root tree
4268  */
4269 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4270 {
4271         struct btrfs_space_info *sinfo;
4272         u64 num_bytes;
4273         u64 meta_used;
4274         u64 data_used;
4275         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4276
4277         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4278         spin_lock(&sinfo->lock);
4279         data_used = sinfo->bytes_used;
4280         spin_unlock(&sinfo->lock);
4281
4282         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4283         spin_lock(&sinfo->lock);
4284         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4285                 data_used = 0;
4286         meta_used = sinfo->bytes_used;
4287         spin_unlock(&sinfo->lock);
4288
4289         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4290                     csum_size * 2;
4291         num_bytes += div64_u64(data_used + meta_used, 50);
4292
4293         if (num_bytes * 3 > meta_used)
4294                 num_bytes = div64_u64(meta_used, 3);
4295
4296         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4297 }
4298
4299 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4300 {
4301         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4302         struct btrfs_space_info *sinfo = block_rsv->space_info;
4303         u64 num_bytes;
4304
4305         num_bytes = calc_global_metadata_size(fs_info);
4306
4307         spin_lock(&sinfo->lock);
4308         spin_lock(&block_rsv->lock);
4309
4310         block_rsv->size = num_bytes;
4311
4312         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4313                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4314                     sinfo->bytes_may_use;
4315
4316         if (sinfo->total_bytes > num_bytes) {
4317                 num_bytes = sinfo->total_bytes - num_bytes;
4318                 block_rsv->reserved += num_bytes;
4319                 sinfo->bytes_may_use += num_bytes;
4320                 trace_btrfs_space_reservation(fs_info, "space_info",
4321                                       sinfo->flags, num_bytes, 1);
4322         }
4323
4324         if (block_rsv->reserved >= block_rsv->size) {
4325                 num_bytes = block_rsv->reserved - block_rsv->size;
4326                 sinfo->bytes_may_use -= num_bytes;
4327                 trace_btrfs_space_reservation(fs_info, "space_info",
4328                                       sinfo->flags, num_bytes, 0);
4329                 sinfo->reservation_progress++;
4330                 block_rsv->reserved = block_rsv->size;
4331                 block_rsv->full = 1;
4332         }
4333
4334         spin_unlock(&block_rsv->lock);
4335         spin_unlock(&sinfo->lock);
4336 }
4337
4338 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4339 {
4340         struct btrfs_space_info *space_info;
4341
4342         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4343         fs_info->chunk_block_rsv.space_info = space_info;
4344
4345         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4346         fs_info->global_block_rsv.space_info = space_info;
4347         fs_info->delalloc_block_rsv.space_info = space_info;
4348         fs_info->trans_block_rsv.space_info = space_info;
4349         fs_info->empty_block_rsv.space_info = space_info;
4350         fs_info->delayed_block_rsv.space_info = space_info;
4351
4352         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4353         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4354         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4355         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4356         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4357
4358         update_global_block_rsv(fs_info);
4359 }
4360
4361 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4362 {
4363         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4364                                 (u64)-1);
4365         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4366         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4367         WARN_ON(fs_info->trans_block_rsv.size > 0);
4368         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4369         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4370         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4371         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4372         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4373 }
4374
4375 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4376                                   struct btrfs_root *root)
4377 {
4378         if (!trans->block_rsv)
4379                 return;
4380
4381         if (!trans->bytes_reserved)
4382                 return;
4383
4384         trace_btrfs_space_reservation(root->fs_info, "transaction",
4385                                       trans->transid, trans->bytes_reserved, 0);
4386         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4387         trans->bytes_reserved = 0;
4388 }
4389
4390 /* Can only return 0 or -ENOSPC */
4391 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4392                                   struct inode *inode)
4393 {
4394         struct btrfs_root *root = BTRFS_I(inode)->root;
4395         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4396         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4397
4398         /*
4399          * We need to hold space in order to delete our orphan item once we've
4400          * added it, so this takes the reservation so we can release it later
4401          * when we are truly done with the orphan item.
4402          */
4403         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4404         trace_btrfs_space_reservation(root->fs_info, "orphan",
4405                                       btrfs_ino(inode), num_bytes, 1);
4406         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4407 }
4408
4409 void btrfs_orphan_release_metadata(struct inode *inode)
4410 {
4411         struct btrfs_root *root = BTRFS_I(inode)->root;
4412         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4413         trace_btrfs_space_reservation(root->fs_info, "orphan",
4414                                       btrfs_ino(inode), num_bytes, 0);
4415         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4416 }
4417
4418 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4419                                 struct btrfs_pending_snapshot *pending)
4420 {
4421         struct btrfs_root *root = pending->root;
4422         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4423         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4424         /*
4425          * two for root back/forward refs, two for directory entries
4426          * and one for root of the snapshot.
4427          */
4428         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4429         dst_rsv->space_info = src_rsv->space_info;
4430         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4431 }
4432
4433 /**
4434  * drop_outstanding_extent - drop an outstanding extent
4435  * @inode: the inode we're dropping the extent for
4436  *
4437  * This is called when we are freeing up an outstanding extent, either called
4438  * after an error or after an extent is written.  This will return the number of
4439  * reserved extents that need to be freed.  This must be called with
4440  * BTRFS_I(inode)->lock held.
4441  */
4442 static unsigned drop_outstanding_extent(struct inode *inode)
4443 {
4444         unsigned drop_inode_space = 0;
4445         unsigned dropped_extents = 0;
4446
4447         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4448         BTRFS_I(inode)->outstanding_extents--;
4449
4450         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4451             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4452                                &BTRFS_I(inode)->runtime_flags))
4453                 drop_inode_space = 1;
4454
4455         /*
4456          * If we have more or the same amount of outsanding extents than we have
4457          * reserved then we need to leave the reserved extents count alone.
4458          */
4459         if (BTRFS_I(inode)->outstanding_extents >=
4460             BTRFS_I(inode)->reserved_extents)
4461                 return drop_inode_space;
4462
4463         dropped_extents = BTRFS_I(inode)->reserved_extents -
4464                 BTRFS_I(inode)->outstanding_extents;
4465         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4466         return dropped_extents + drop_inode_space;
4467 }
4468
4469 /**
4470  * calc_csum_metadata_size - return the amount of metada space that must be
4471  *      reserved/free'd for the given bytes.
4472  * @inode: the inode we're manipulating
4473  * @num_bytes: the number of bytes in question
4474  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4475  *
4476  * This adjusts the number of csum_bytes in the inode and then returns the
4477  * correct amount of metadata that must either be reserved or freed.  We
4478  * calculate how many checksums we can fit into one leaf and then divide the
4479  * number of bytes that will need to be checksumed by this value to figure out
4480  * how many checksums will be required.  If we are adding bytes then the number
4481  * may go up and we will return the number of additional bytes that must be
4482  * reserved.  If it is going down we will return the number of bytes that must
4483  * be freed.
4484  *
4485  * This must be called with BTRFS_I(inode)->lock held.
4486  */
4487 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4488                                    int reserve)
4489 {
4490         struct btrfs_root *root = BTRFS_I(inode)->root;
4491         u64 csum_size;
4492         int num_csums_per_leaf;
4493         int num_csums;
4494         int old_csums;
4495
4496         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4497             BTRFS_I(inode)->csum_bytes == 0)
4498                 return 0;
4499
4500         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4501         if (reserve)
4502                 BTRFS_I(inode)->csum_bytes += num_bytes;
4503         else
4504                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4505         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4506         num_csums_per_leaf = (int)div64_u64(csum_size,
4507                                             sizeof(struct btrfs_csum_item) +
4508                                             sizeof(struct btrfs_disk_key));
4509         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4510         num_csums = num_csums + num_csums_per_leaf - 1;
4511         num_csums = num_csums / num_csums_per_leaf;
4512
4513         old_csums = old_csums + num_csums_per_leaf - 1;
4514         old_csums = old_csums / num_csums_per_leaf;
4515
4516         /* No change, no need to reserve more */
4517         if (old_csums == num_csums)
4518                 return 0;
4519
4520         if (reserve)
4521                 return btrfs_calc_trans_metadata_size(root,
4522                                                       num_csums - old_csums);
4523
4524         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4525 }
4526
4527 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4528 {
4529         struct btrfs_root *root = BTRFS_I(inode)->root;
4530         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4531         u64 to_reserve = 0;
4532         u64 csum_bytes;
4533         unsigned nr_extents = 0;
4534         int extra_reserve = 0;
4535         int flush = 1;
4536         int ret;
4537
4538         /* Need to be holding the i_mutex here if we aren't free space cache */
4539         if (btrfs_is_free_space_inode(inode))
4540                 flush = 0;
4541
4542         if (flush && btrfs_transaction_in_commit(root->fs_info))
4543                 schedule_timeout(1);
4544
4545         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4546         num_bytes = ALIGN(num_bytes, root->sectorsize);
4547
4548         spin_lock(&BTRFS_I(inode)->lock);
4549         BTRFS_I(inode)->outstanding_extents++;
4550
4551         if (BTRFS_I(inode)->outstanding_extents >
4552             BTRFS_I(inode)->reserved_extents)
4553                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4554                         BTRFS_I(inode)->reserved_extents;
4555
4556         /*
4557          * Add an item to reserve for updating the inode when we complete the
4558          * delalloc io.
4559          */
4560         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4561                       &BTRFS_I(inode)->runtime_flags)) {
4562                 nr_extents++;
4563                 extra_reserve = 1;
4564         }
4565
4566         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4567         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4568         csum_bytes = BTRFS_I(inode)->csum_bytes;
4569         spin_unlock(&BTRFS_I(inode)->lock);
4570
4571         if (root->fs_info->quota_enabled) {
4572                 ret = btrfs_qgroup_reserve(root, num_bytes +
4573                                            nr_extents * root->leafsize);
4574                 if (ret)
4575                         return ret;
4576         }
4577
4578         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4579         if (ret) {
4580                 u64 to_free = 0;
4581                 unsigned dropped;
4582
4583                 spin_lock(&BTRFS_I(inode)->lock);
4584                 dropped = drop_outstanding_extent(inode);
4585                 /*
4586                  * If the inodes csum_bytes is the same as the original
4587                  * csum_bytes then we know we haven't raced with any free()ers
4588                  * so we can just reduce our inodes csum bytes and carry on.
4589                  * Otherwise we have to do the normal free thing to account for
4590                  * the case that the free side didn't free up its reserve
4591                  * because of this outstanding reservation.
4592                  */
4593                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4594                         calc_csum_metadata_size(inode, num_bytes, 0);
4595                 else
4596                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4597                 spin_unlock(&BTRFS_I(inode)->lock);
4598                 if (dropped)
4599                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4600
4601                 if (to_free) {
4602                         btrfs_block_rsv_release(root, block_rsv, to_free);
4603                         trace_btrfs_space_reservation(root->fs_info,
4604                                                       "delalloc",
4605                                                       btrfs_ino(inode),
4606                                                       to_free, 0);
4607                 }
4608                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4609                 return ret;
4610         }
4611
4612         spin_lock(&BTRFS_I(inode)->lock);
4613         if (extra_reserve) {
4614                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4615                         &BTRFS_I(inode)->runtime_flags);
4616                 nr_extents--;
4617         }
4618         BTRFS_I(inode)->reserved_extents += nr_extents;
4619         spin_unlock(&BTRFS_I(inode)->lock);
4620         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4621
4622         if (to_reserve)
4623                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4624                                               btrfs_ino(inode), to_reserve, 1);
4625         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4626
4627         return 0;
4628 }
4629
4630 /**
4631  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4632  * @inode: the inode to release the reservation for
4633  * @num_bytes: the number of bytes we're releasing
4634  *
4635  * This will release the metadata reservation for an inode.  This can be called
4636  * once we complete IO for a given set of bytes to release their metadata
4637  * reservations.
4638  */
4639 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4640 {
4641         struct btrfs_root *root = BTRFS_I(inode)->root;
4642         u64 to_free = 0;
4643         unsigned dropped;
4644
4645         num_bytes = ALIGN(num_bytes, root->sectorsize);
4646         spin_lock(&BTRFS_I(inode)->lock);
4647         dropped = drop_outstanding_extent(inode);
4648
4649         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4650         spin_unlock(&BTRFS_I(inode)->lock);
4651         if (dropped > 0)
4652                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4653
4654         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4655                                       btrfs_ino(inode), to_free, 0);
4656         if (root->fs_info->quota_enabled) {
4657                 btrfs_qgroup_free(root, num_bytes +
4658                                         dropped * root->leafsize);
4659         }
4660
4661         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4662                                 to_free);
4663 }
4664
4665 /**
4666  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4667  * @inode: inode we're writing to
4668  * @num_bytes: the number of bytes we want to allocate
4669  *
4670  * This will do the following things
4671  *
4672  * o reserve space in the data space info for num_bytes
4673  * o reserve space in the metadata space info based on number of outstanding
4674  *   extents and how much csums will be needed
4675  * o add to the inodes ->delalloc_bytes
4676  * o add it to the fs_info's delalloc inodes list.
4677  *
4678  * This will return 0 for success and -ENOSPC if there is no space left.
4679  */
4680 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4681 {
4682         int ret;
4683
4684         ret = btrfs_check_data_free_space(inode, num_bytes);
4685         if (ret)
4686                 return ret;
4687
4688         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4689         if (ret) {
4690                 btrfs_free_reserved_data_space(inode, num_bytes);
4691                 return ret;
4692         }
4693
4694         return 0;
4695 }
4696
4697 /**
4698  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4699  * @inode: inode we're releasing space for
4700  * @num_bytes: the number of bytes we want to free up
4701  *
4702  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4703  * called in the case that we don't need the metadata AND data reservations
4704  * anymore.  So if there is an error or we insert an inline extent.
4705  *
4706  * This function will release the metadata space that was not used and will
4707  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4708  * list if there are no delalloc bytes left.
4709  */
4710 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4711 {
4712         btrfs_delalloc_release_metadata(inode, num_bytes);
4713         btrfs_free_reserved_data_space(inode, num_bytes);
4714 }
4715
4716 static int update_block_group(struct btrfs_trans_handle *trans,
4717                               struct btrfs_root *root,
4718                               u64 bytenr, u64 num_bytes, int alloc)
4719 {
4720         struct btrfs_block_group_cache *cache = NULL;
4721         struct btrfs_fs_info *info = root->fs_info;
4722         u64 total = num_bytes;
4723         u64 old_val;
4724         u64 byte_in_group;
4725         int factor;
4726
4727         /* block accounting for super block */
4728         spin_lock(&info->delalloc_lock);
4729         old_val = btrfs_super_bytes_used(info->super_copy);
4730         if (alloc)
4731                 old_val += num_bytes;
4732         else
4733                 old_val -= num_bytes;
4734         btrfs_set_super_bytes_used(info->super_copy, old_val);
4735         spin_unlock(&info->delalloc_lock);
4736
4737         while (total) {
4738                 cache = btrfs_lookup_block_group(info, bytenr);
4739                 if (!cache)
4740                         return -ENOENT;
4741                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4742                                     BTRFS_BLOCK_GROUP_RAID1 |
4743                                     BTRFS_BLOCK_GROUP_RAID10))
4744                         factor = 2;
4745                 else
4746                         factor = 1;
4747                 /*
4748                  * If this block group has free space cache written out, we
4749                  * need to make sure to load it if we are removing space.  This
4750                  * is because we need the unpinning stage to actually add the
4751                  * space back to the block group, otherwise we will leak space.
4752                  */
4753                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4754                         cache_block_group(cache, trans, NULL, 1);
4755
4756                 byte_in_group = bytenr - cache->key.objectid;
4757                 WARN_ON(byte_in_group > cache->key.offset);
4758
4759                 spin_lock(&cache->space_info->lock);
4760                 spin_lock(&cache->lock);
4761
4762                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4763                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4764                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4765
4766                 cache->dirty = 1;
4767                 old_val = btrfs_block_group_used(&cache->item);
4768                 num_bytes = min(total, cache->key.offset - byte_in_group);
4769                 if (alloc) {
4770                         old_val += num_bytes;
4771                         btrfs_set_block_group_used(&cache->item, old_val);
4772                         cache->reserved -= num_bytes;
4773                         cache->space_info->bytes_reserved -= num_bytes;
4774                         cache->space_info->bytes_used += num_bytes;
4775                         cache->space_info->disk_used += num_bytes * factor;
4776                         spin_unlock(&cache->lock);
4777                         spin_unlock(&cache->space_info->lock);
4778                 } else {
4779                         old_val -= num_bytes;
4780                         btrfs_set_block_group_used(&cache->item, old_val);
4781                         cache->pinned += num_bytes;
4782                         cache->space_info->bytes_pinned += num_bytes;
4783                         cache->space_info->bytes_used -= num_bytes;
4784                         cache->space_info->disk_used -= num_bytes * factor;
4785                         spin_unlock(&cache->lock);
4786                         spin_unlock(&cache->space_info->lock);
4787
4788                         set_extent_dirty(info->pinned_extents,
4789                                          bytenr, bytenr + num_bytes - 1,
4790                                          GFP_NOFS | __GFP_NOFAIL);
4791                 }
4792                 btrfs_put_block_group(cache);
4793                 total -= num_bytes;
4794                 bytenr += num_bytes;
4795         }
4796         return 0;
4797 }
4798
4799 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4800 {
4801         struct btrfs_block_group_cache *cache;
4802         u64 bytenr;
4803
4804         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4805         if (!cache)
4806                 return 0;
4807
4808         bytenr = cache->key.objectid;
4809         btrfs_put_block_group(cache);
4810
4811         return bytenr;
4812 }
4813
4814 static int pin_down_extent(struct btrfs_root *root,
4815                            struct btrfs_block_group_cache *cache,
4816                            u64 bytenr, u64 num_bytes, int reserved)
4817 {
4818         spin_lock(&cache->space_info->lock);
4819         spin_lock(&cache->lock);
4820         cache->pinned += num_bytes;
4821         cache->space_info->bytes_pinned += num_bytes;
4822         if (reserved) {
4823                 cache->reserved -= num_bytes;
4824                 cache->space_info->bytes_reserved -= num_bytes;
4825         }
4826         spin_unlock(&cache->lock);
4827         spin_unlock(&cache->space_info->lock);
4828
4829         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4830                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4831         return 0;
4832 }
4833
4834 /*
4835  * this function must be called within transaction
4836  */
4837 int btrfs_pin_extent(struct btrfs_root *root,
4838                      u64 bytenr, u64 num_bytes, int reserved)
4839 {
4840         struct btrfs_block_group_cache *cache;
4841
4842         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4843         BUG_ON(!cache); /* Logic error */
4844
4845         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4846
4847         btrfs_put_block_group(cache);
4848         return 0;
4849 }
4850
4851 /*
4852  * this function must be called within transaction
4853  */
4854 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4855                                     struct btrfs_root *root,
4856                                     u64 bytenr, u64 num_bytes)
4857 {
4858         struct btrfs_block_group_cache *cache;
4859
4860         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4861         BUG_ON(!cache); /* Logic error */
4862
4863         /*
4864          * pull in the free space cache (if any) so that our pin
4865          * removes the free space from the cache.  We have load_only set
4866          * to one because the slow code to read in the free extents does check
4867          * the pinned extents.
4868          */
4869         cache_block_group(cache, trans, root, 1);
4870
4871         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4872
4873         /* remove us from the free space cache (if we're there at all) */
4874         btrfs_remove_free_space(cache, bytenr, num_bytes);
4875         btrfs_put_block_group(cache);
4876         return 0;
4877 }
4878
4879 /**
4880  * btrfs_update_reserved_bytes - update the block_group and space info counters
4881  * @cache:      The cache we are manipulating
4882  * @num_bytes:  The number of bytes in question
4883  * @reserve:    One of the reservation enums
4884  *
4885  * This is called by the allocator when it reserves space, or by somebody who is
4886  * freeing space that was never actually used on disk.  For example if you
4887  * reserve some space for a new leaf in transaction A and before transaction A
4888  * commits you free that leaf, you call this with reserve set to 0 in order to
4889  * clear the reservation.
4890  *
4891  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4892  * ENOSPC accounting.  For data we handle the reservation through clearing the
4893  * delalloc bits in the io_tree.  We have to do this since we could end up
4894  * allocating less disk space for the amount of data we have reserved in the
4895  * case of compression.
4896  *
4897  * If this is a reservation and the block group has become read only we cannot
4898  * make the reservation and return -EAGAIN, otherwise this function always
4899  * succeeds.
4900  */
4901 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4902                                        u64 num_bytes, int reserve)
4903 {
4904         struct btrfs_space_info *space_info = cache->space_info;
4905         int ret = 0;
4906
4907         spin_lock(&space_info->lock);
4908         spin_lock(&cache->lock);
4909         if (reserve != RESERVE_FREE) {
4910                 if (cache->ro) {
4911                         ret = -EAGAIN;
4912                 } else {
4913                         cache->reserved += num_bytes;
4914                         space_info->bytes_reserved += num_bytes;
4915                         if (reserve == RESERVE_ALLOC) {
4916                                 trace_btrfs_space_reservation(cache->fs_info,
4917                                                 "space_info", space_info->flags,
4918                                                 num_bytes, 0);
4919                                 space_info->bytes_may_use -= num_bytes;
4920                         }
4921                 }
4922         } else {
4923                 if (cache->ro)
4924                         space_info->bytes_readonly += num_bytes;
4925                 cache->reserved -= num_bytes;
4926                 space_info->bytes_reserved -= num_bytes;
4927                 space_info->reservation_progress++;
4928         }
4929         spin_unlock(&cache->lock);
4930         spin_unlock(&space_info->lock);
4931         return ret;
4932 }
4933
4934 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4935                                 struct btrfs_root *root)
4936 {
4937         struct btrfs_fs_info *fs_info = root->fs_info;
4938         struct btrfs_caching_control *next;
4939         struct btrfs_caching_control *caching_ctl;
4940         struct btrfs_block_group_cache *cache;
4941
4942         down_write(&fs_info->extent_commit_sem);
4943
4944         list_for_each_entry_safe(caching_ctl, next,
4945                                  &fs_info->caching_block_groups, list) {
4946                 cache = caching_ctl->block_group;
4947                 if (block_group_cache_done(cache)) {
4948                         cache->last_byte_to_unpin = (u64)-1;
4949                         list_del_init(&caching_ctl->list);
4950                         put_caching_control(caching_ctl);
4951                 } else {
4952                         cache->last_byte_to_unpin = caching_ctl->progress;
4953                 }
4954         }
4955
4956         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4957                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4958         else
4959                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4960
4961         up_write(&fs_info->extent_commit_sem);
4962
4963         update_global_block_rsv(fs_info);
4964 }
4965
4966 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4967 {
4968         struct btrfs_fs_info *fs_info = root->fs_info;
4969         struct btrfs_block_group_cache *cache = NULL;
4970         u64 len;
4971
4972         while (start <= end) {
4973                 if (!cache ||
4974                     start >= cache->key.objectid + cache->key.offset) {
4975                         if (cache)
4976                                 btrfs_put_block_group(cache);
4977                         cache = btrfs_lookup_block_group(fs_info, start);
4978                         BUG_ON(!cache); /* Logic error */
4979                 }
4980
4981                 len = cache->key.objectid + cache->key.offset - start;
4982                 len = min(len, end + 1 - start);
4983
4984                 if (start < cache->last_byte_to_unpin) {
4985                         len = min(len, cache->last_byte_to_unpin - start);
4986                         btrfs_add_free_space(cache, start, len);
4987                 }
4988
4989                 start += len;
4990
4991                 spin_lock(&cache->space_info->lock);
4992                 spin_lock(&cache->lock);
4993                 cache->pinned -= len;
4994                 cache->space_info->bytes_pinned -= len;
4995                 if (cache->ro)
4996                         cache->space_info->bytes_readonly += len;
4997                 spin_unlock(&cache->lock);
4998                 spin_unlock(&cache->space_info->lock);
4999         }
5000
5001         if (cache)
5002                 btrfs_put_block_group(cache);
5003         return 0;
5004 }
5005
5006 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5007                                struct btrfs_root *root)
5008 {
5009         struct btrfs_fs_info *fs_info = root->fs_info;
5010         struct extent_io_tree *unpin;
5011         u64 start;
5012         u64 end;
5013         int ret;
5014
5015         if (trans->aborted)
5016                 return 0;
5017
5018         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5019                 unpin = &fs_info->freed_extents[1];
5020         else
5021                 unpin = &fs_info->freed_extents[0];
5022
5023         while (1) {
5024                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5025                                             EXTENT_DIRTY);
5026                 if (ret)
5027                         break;
5028
5029                 if (btrfs_test_opt(root, DISCARD))
5030                         ret = btrfs_discard_extent(root, start,
5031                                                    end + 1 - start, NULL);
5032
5033                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5034                 unpin_extent_range(root, start, end);
5035                 cond_resched();
5036         }
5037
5038         return 0;
5039 }
5040
5041 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5042                                 struct btrfs_root *root,
5043                                 u64 bytenr, u64 num_bytes, u64 parent,
5044                                 u64 root_objectid, u64 owner_objectid,
5045                                 u64 owner_offset, int refs_to_drop,
5046                                 struct btrfs_delayed_extent_op *extent_op)
5047 {
5048         struct btrfs_key key;
5049         struct btrfs_path *path;
5050         struct btrfs_fs_info *info = root->fs_info;
5051         struct btrfs_root *extent_root = info->extent_root;
5052         struct extent_buffer *leaf;
5053         struct btrfs_extent_item *ei;
5054         struct btrfs_extent_inline_ref *iref;
5055         int ret;
5056         int is_data;
5057         int extent_slot = 0;
5058         int found_extent = 0;
5059         int num_to_del = 1;
5060         u32 item_size;
5061         u64 refs;
5062
5063         path = btrfs_alloc_path();
5064         if (!path)
5065                 return -ENOMEM;
5066
5067         path->reada = 1;
5068         path->leave_spinning = 1;
5069
5070         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5071         BUG_ON(!is_data && refs_to_drop != 1);
5072
5073         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5074                                     bytenr, num_bytes, parent,
5075                                     root_objectid, owner_objectid,
5076                                     owner_offset);
5077         if (ret == 0) {
5078                 extent_slot = path->slots[0];
5079                 while (extent_slot >= 0) {
5080                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5081                                               extent_slot);
5082                         if (key.objectid != bytenr)
5083                                 break;
5084                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5085                             key.offset == num_bytes) {
5086                                 found_extent = 1;
5087                                 break;
5088                         }
5089                         if (path->slots[0] - extent_slot > 5)
5090                                 break;
5091                         extent_slot--;
5092                 }
5093 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5094                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5095                 if (found_extent && item_size < sizeof(*ei))
5096                         found_extent = 0;
5097 #endif
5098                 if (!found_extent) {
5099                         BUG_ON(iref);
5100                         ret = remove_extent_backref(trans, extent_root, path,
5101                                                     NULL, refs_to_drop,
5102                                                     is_data);
5103                         if (ret)
5104                                 goto abort;
5105                         btrfs_release_path(path);
5106                         path->leave_spinning = 1;
5107
5108                         key.objectid = bytenr;
5109                         key.type = BTRFS_EXTENT_ITEM_KEY;
5110                         key.offset = num_bytes;
5111
5112                         ret = btrfs_search_slot(trans, extent_root,
5113                                                 &key, path, -1, 1);
5114                         if (ret) {
5115                                 printk(KERN_ERR "umm, got %d back from search"
5116                                        ", was looking for %llu\n", ret,
5117                                        (unsigned long long)bytenr);
5118                                 if (ret > 0)
5119                                         btrfs_print_leaf(extent_root,
5120                                                          path->nodes[0]);
5121                         }
5122                         if (ret < 0)
5123                                 goto abort;
5124                         extent_slot = path->slots[0];
5125                 }
5126         } else if (ret == -ENOENT) {
5127                 btrfs_print_leaf(extent_root, path->nodes[0]);
5128                 WARN_ON(1);
5129                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
5130                        "parent %llu root %llu  owner %llu offset %llu\n",
5131                        (unsigned long long)bytenr,
5132                        (unsigned long long)parent,
5133                        (unsigned long long)root_objectid,
5134                        (unsigned long long)owner_objectid,
5135                        (unsigned long long)owner_offset);
5136         } else {
5137                 goto abort;
5138         }
5139
5140         leaf = path->nodes[0];
5141         item_size = btrfs_item_size_nr(leaf, extent_slot);
5142 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5143         if (item_size < sizeof(*ei)) {
5144                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5145                 ret = convert_extent_item_v0(trans, extent_root, path,
5146                                              owner_objectid, 0);
5147                 if (ret < 0)
5148                         goto abort;
5149
5150                 btrfs_release_path(path);
5151                 path->leave_spinning = 1;
5152
5153                 key.objectid = bytenr;
5154                 key.type = BTRFS_EXTENT_ITEM_KEY;
5155                 key.offset = num_bytes;
5156
5157                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5158                                         -1, 1);
5159                 if (ret) {
5160                         printk(KERN_ERR "umm, got %d back from search"
5161                                ", was looking for %llu\n", ret,
5162                                (unsigned long long)bytenr);
5163                         btrfs_print_leaf(extent_root, path->nodes[0]);
5164                 }
5165                 if (ret < 0)
5166                         goto abort;
5167                 extent_slot = path->slots[0];
5168                 leaf = path->nodes[0];
5169                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5170         }
5171 #endif
5172         BUG_ON(item_size < sizeof(*ei));
5173         ei = btrfs_item_ptr(leaf, extent_slot,
5174                             struct btrfs_extent_item);
5175         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5176                 struct btrfs_tree_block_info *bi;
5177                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5178                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5179                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5180         }
5181
5182         refs = btrfs_extent_refs(leaf, ei);
5183         BUG_ON(refs < refs_to_drop);
5184         refs -= refs_to_drop;
5185
5186         if (refs > 0) {
5187                 if (extent_op)
5188                         __run_delayed_extent_op(extent_op, leaf, ei);
5189                 /*
5190                  * In the case of inline back ref, reference count will
5191                  * be updated by remove_extent_backref
5192                  */
5193                 if (iref) {
5194                         BUG_ON(!found_extent);
5195                 } else {
5196                         btrfs_set_extent_refs(leaf, ei, refs);
5197                         btrfs_mark_buffer_dirty(leaf);
5198                 }
5199                 if (found_extent) {
5200                         ret = remove_extent_backref(trans, extent_root, path,
5201                                                     iref, refs_to_drop,
5202                                                     is_data);
5203                         if (ret)
5204                                 goto abort;
5205                 }
5206         } else {
5207                 if (found_extent) {
5208                         BUG_ON(is_data && refs_to_drop !=
5209                                extent_data_ref_count(root, path, iref));
5210                         if (iref) {
5211                                 BUG_ON(path->slots[0] != extent_slot);
5212                         } else {
5213                                 BUG_ON(path->slots[0] != extent_slot + 1);
5214                                 path->slots[0] = extent_slot;
5215                                 num_to_del = 2;
5216                         }
5217                 }
5218
5219                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5220                                       num_to_del);
5221                 if (ret)
5222                         goto abort;
5223                 btrfs_release_path(path);
5224
5225                 if (is_data) {
5226                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5227                         if (ret)
5228                                 goto abort;
5229                 }
5230
5231                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5232                 if (ret)
5233                         goto abort;
5234         }
5235 out:
5236         btrfs_free_path(path);
5237         return ret;
5238
5239 abort:
5240         btrfs_abort_transaction(trans, extent_root, ret);
5241         goto out;
5242 }
5243
5244 /*
5245  * when we free an block, it is possible (and likely) that we free the last
5246  * delayed ref for that extent as well.  This searches the delayed ref tree for
5247  * a given extent, and if there are no other delayed refs to be processed, it
5248  * removes it from the tree.
5249  */
5250 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5251                                       struct btrfs_root *root, u64 bytenr)
5252 {
5253         struct btrfs_delayed_ref_head *head;
5254         struct btrfs_delayed_ref_root *delayed_refs;
5255         struct btrfs_delayed_ref_node *ref;
5256         struct rb_node *node;
5257         int ret = 0;
5258
5259         delayed_refs = &trans->transaction->delayed_refs;
5260         spin_lock(&delayed_refs->lock);
5261         head = btrfs_find_delayed_ref_head(trans, bytenr);
5262         if (!head)
5263                 goto out;
5264
5265         node = rb_prev(&head->node.rb_node);
5266         if (!node)
5267                 goto out;
5268
5269         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5270
5271         /* there are still entries for this ref, we can't drop it */
5272         if (ref->bytenr == bytenr)
5273                 goto out;
5274
5275         if (head->extent_op) {
5276                 if (!head->must_insert_reserved)
5277                         goto out;
5278                 kfree(head->extent_op);
5279                 head->extent_op = NULL;
5280         }
5281
5282         /*
5283          * waiting for the lock here would deadlock.  If someone else has it
5284          * locked they are already in the process of dropping it anyway
5285          */
5286         if (!mutex_trylock(&head->mutex))
5287                 goto out;
5288
5289         /*
5290          * at this point we have a head with no other entries.  Go
5291          * ahead and process it.
5292          */
5293         head->node.in_tree = 0;
5294         rb_erase(&head->node.rb_node, &delayed_refs->root);
5295
5296         delayed_refs->num_entries--;
5297         smp_mb();
5298         if (waitqueue_active(&root->fs_info->tree_mod_seq_wait))
5299                 wake_up(&root->fs_info->tree_mod_seq_wait);
5300
5301         /*
5302          * we don't take a ref on the node because we're removing it from the
5303          * tree, so we just steal the ref the tree was holding.
5304          */
5305         delayed_refs->num_heads--;
5306         if (list_empty(&head->cluster))
5307                 delayed_refs->num_heads_ready--;
5308
5309         list_del_init(&head->cluster);
5310         spin_unlock(&delayed_refs->lock);
5311
5312         BUG_ON(head->extent_op);
5313         if (head->must_insert_reserved)
5314                 ret = 1;
5315
5316         mutex_unlock(&head->mutex);
5317         btrfs_put_delayed_ref(&head->node);
5318         return ret;
5319 out:
5320         spin_unlock(&delayed_refs->lock);
5321         return 0;
5322 }
5323
5324 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5325                            struct btrfs_root *root,
5326                            struct extent_buffer *buf,
5327                            u64 parent, int last_ref)
5328 {
5329         struct btrfs_block_group_cache *cache = NULL;
5330         int ret;
5331
5332         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5333                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5334                                         buf->start, buf->len,
5335                                         parent, root->root_key.objectid,
5336                                         btrfs_header_level(buf),
5337                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5338                 BUG_ON(ret); /* -ENOMEM */
5339         }
5340
5341         if (!last_ref)
5342                 return;
5343
5344         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5345
5346         if (btrfs_header_generation(buf) == trans->transid) {
5347                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5348                         ret = check_ref_cleanup(trans, root, buf->start);
5349                         if (!ret)
5350                                 goto out;
5351                 }
5352
5353                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5354                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5355                         goto out;
5356                 }
5357
5358                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5359
5360                 btrfs_add_free_space(cache, buf->start, buf->len);
5361                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5362         }
5363 out:
5364         /*
5365          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5366          * anymore.
5367          */
5368         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5369         btrfs_put_block_group(cache);
5370 }
5371
5372 /* Can return -ENOMEM */
5373 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5374                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5375                       u64 owner, u64 offset, int for_cow)
5376 {
5377         int ret;
5378         struct btrfs_fs_info *fs_info = root->fs_info;
5379
5380         /*
5381          * tree log blocks never actually go into the extent allocation
5382          * tree, just update pinning info and exit early.
5383          */
5384         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5385                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5386                 /* unlocks the pinned mutex */
5387                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5388                 ret = 0;
5389         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5390                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5391                                         num_bytes,
5392                                         parent, root_objectid, (int)owner,
5393                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5394         } else {
5395                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5396                                                 num_bytes,
5397                                                 parent, root_objectid, owner,
5398                                                 offset, BTRFS_DROP_DELAYED_REF,
5399                                                 NULL, for_cow);
5400         }
5401         return ret;
5402 }
5403
5404 static u64 stripe_align(struct btrfs_root *root, u64 val)
5405 {
5406         u64 mask = ((u64)root->stripesize - 1);
5407         u64 ret = (val + mask) & ~mask;
5408         return ret;
5409 }
5410
5411 /*
5412  * when we wait for progress in the block group caching, its because
5413  * our allocation attempt failed at least once.  So, we must sleep
5414  * and let some progress happen before we try again.
5415  *
5416  * This function will sleep at least once waiting for new free space to
5417  * show up, and then it will check the block group free space numbers
5418  * for our min num_bytes.  Another option is to have it go ahead
5419  * and look in the rbtree for a free extent of a given size, but this
5420  * is a good start.
5421  */
5422 static noinline int
5423 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5424                                 u64 num_bytes)
5425 {
5426         struct btrfs_caching_control *caching_ctl;
5427         DEFINE_WAIT(wait);
5428
5429         caching_ctl = get_caching_control(cache);
5430         if (!caching_ctl)
5431                 return 0;
5432
5433         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5434                    (cache->free_space_ctl->free_space >= num_bytes));
5435
5436         put_caching_control(caching_ctl);
5437         return 0;
5438 }
5439
5440 static noinline int
5441 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5442 {
5443         struct btrfs_caching_control *caching_ctl;
5444         DEFINE_WAIT(wait);
5445
5446         caching_ctl = get_caching_control(cache);
5447         if (!caching_ctl)
5448                 return 0;
5449
5450         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5451
5452         put_caching_control(caching_ctl);
5453         return 0;
5454 }
5455
5456 static int __get_block_group_index(u64 flags)
5457 {
5458         int index;
5459
5460         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5461                 index = 0;
5462         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5463                 index = 1;
5464         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5465                 index = 2;
5466         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5467                 index = 3;
5468         else
5469                 index = 4;
5470
5471         return index;
5472 }
5473
5474 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5475 {
5476         return __get_block_group_index(cache->flags);
5477 }
5478
5479 enum btrfs_loop_type {
5480         LOOP_CACHING_NOWAIT = 0,
5481         LOOP_CACHING_WAIT = 1,
5482         LOOP_ALLOC_CHUNK = 2,
5483         LOOP_NO_EMPTY_SIZE = 3,
5484 };
5485
5486 /*
5487  * walks the btree of allocated extents and find a hole of a given size.
5488  * The key ins is changed to record the hole:
5489  * ins->objectid == block start
5490  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5491  * ins->offset == number of blocks
5492  * Any available blocks before search_start are skipped.
5493  */
5494 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5495                                      struct btrfs_root *orig_root,
5496                                      u64 num_bytes, u64 empty_size,
5497                                      u64 hint_byte, struct btrfs_key *ins,
5498                                      u64 data)
5499 {
5500         int ret = 0;
5501         struct btrfs_root *root = orig_root->fs_info->extent_root;
5502         struct btrfs_free_cluster *last_ptr = NULL;
5503         struct btrfs_block_group_cache *block_group = NULL;
5504         struct btrfs_block_group_cache *used_block_group;
5505         u64 search_start = 0;
5506         int empty_cluster = 2 * 1024 * 1024;
5507         int allowed_chunk_alloc = 0;
5508         int done_chunk_alloc = 0;
5509         struct btrfs_space_info *space_info;
5510         int loop = 0;
5511         int index = 0;
5512         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5513                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5514         bool found_uncached_bg = false;
5515         bool failed_cluster_refill = false;
5516         bool failed_alloc = false;
5517         bool use_cluster = true;
5518         bool have_caching_bg = false;
5519
5520         WARN_ON(num_bytes < root->sectorsize);
5521         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5522         ins->objectid = 0;
5523         ins->offset = 0;
5524
5525         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5526
5527         space_info = __find_space_info(root->fs_info, data);
5528         if (!space_info) {
5529                 printk(KERN_ERR "No space info for %llu\n", data);
5530                 return -ENOSPC;
5531         }
5532
5533         /*
5534          * If the space info is for both data and metadata it means we have a
5535          * small filesystem and we can't use the clustering stuff.
5536          */
5537         if (btrfs_mixed_space_info(space_info))
5538                 use_cluster = false;
5539
5540         if (orig_root->ref_cows || empty_size)
5541                 allowed_chunk_alloc = 1;
5542
5543         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5544                 last_ptr = &root->fs_info->meta_alloc_cluster;
5545                 if (!btrfs_test_opt(root, SSD))
5546                         empty_cluster = 64 * 1024;
5547         }
5548
5549         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5550             btrfs_test_opt(root, SSD)) {
5551                 last_ptr = &root->fs_info->data_alloc_cluster;
5552         }
5553
5554         if (last_ptr) {
5555                 spin_lock(&last_ptr->lock);
5556                 if (last_ptr->block_group)
5557                         hint_byte = last_ptr->window_start;
5558                 spin_unlock(&last_ptr->lock);
5559         }
5560
5561         search_start = max(search_start, first_logical_byte(root, 0));
5562         search_start = max(search_start, hint_byte);
5563
5564         if (!last_ptr)
5565                 empty_cluster = 0;
5566
5567         if (search_start == hint_byte) {
5568                 block_group = btrfs_lookup_block_group(root->fs_info,
5569                                                        search_start);
5570                 used_block_group = block_group;
5571                 /*
5572                  * we don't want to use the block group if it doesn't match our
5573                  * allocation bits, or if its not cached.
5574                  *
5575                  * However if we are re-searching with an ideal block group
5576                  * picked out then we don't care that the block group is cached.
5577                  */
5578                 if (block_group && block_group_bits(block_group, data) &&
5579                     block_group->cached != BTRFS_CACHE_NO) {
5580                         down_read(&space_info->groups_sem);
5581                         if (list_empty(&block_group->list) ||
5582                             block_group->ro) {
5583                                 /*
5584                                  * someone is removing this block group,
5585                                  * we can't jump into the have_block_group
5586                                  * target because our list pointers are not
5587                                  * valid
5588                                  */
5589                                 btrfs_put_block_group(block_group);
5590                                 up_read(&space_info->groups_sem);
5591                         } else {
5592                                 index = get_block_group_index(block_group);
5593                                 goto have_block_group;
5594                         }
5595                 } else if (block_group) {
5596                         btrfs_put_block_group(block_group);
5597                 }
5598         }
5599 search:
5600         have_caching_bg = false;
5601         down_read(&space_info->groups_sem);
5602         list_for_each_entry(block_group, &space_info->block_groups[index],
5603                             list) {
5604                 u64 offset;
5605                 int cached;
5606
5607                 used_block_group = block_group;
5608                 btrfs_get_block_group(block_group);
5609                 search_start = block_group->key.objectid;
5610
5611                 /*
5612                  * this can happen if we end up cycling through all the
5613                  * raid types, but we want to make sure we only allocate
5614                  * for the proper type.
5615                  */
5616                 if (!block_group_bits(block_group, data)) {
5617                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5618                                 BTRFS_BLOCK_GROUP_RAID1 |
5619                                 BTRFS_BLOCK_GROUP_RAID10;
5620
5621                         /*
5622                          * if they asked for extra copies and this block group
5623                          * doesn't provide them, bail.  This does allow us to
5624                          * fill raid0 from raid1.
5625                          */
5626                         if ((data & extra) && !(block_group->flags & extra))
5627                                 goto loop;
5628                 }
5629
5630 have_block_group:
5631                 cached = block_group_cache_done(block_group);
5632                 if (unlikely(!cached)) {
5633                         found_uncached_bg = true;
5634                         ret = cache_block_group(block_group, trans,
5635                                                 orig_root, 0);
5636                         BUG_ON(ret < 0);
5637                         ret = 0;
5638                 }
5639
5640                 if (unlikely(block_group->ro))
5641                         goto loop;
5642
5643                 /*
5644                  * Ok we want to try and use the cluster allocator, so
5645                  * lets look there
5646                  */
5647                 if (last_ptr) {
5648                         /*
5649                          * the refill lock keeps out other
5650                          * people trying to start a new cluster
5651                          */
5652                         spin_lock(&last_ptr->refill_lock);
5653                         used_block_group = last_ptr->block_group;
5654                         if (used_block_group != block_group &&
5655                             (!used_block_group ||
5656                              used_block_group->ro ||
5657                              !block_group_bits(used_block_group, data))) {
5658                                 used_block_group = block_group;
5659                                 goto refill_cluster;
5660                         }
5661
5662                         if (used_block_group != block_group)
5663                                 btrfs_get_block_group(used_block_group);
5664
5665                         offset = btrfs_alloc_from_cluster(used_block_group,
5666                           last_ptr, num_bytes, used_block_group->key.objectid);
5667                         if (offset) {
5668                                 /* we have a block, we're done */
5669                                 spin_unlock(&last_ptr->refill_lock);
5670                                 trace_btrfs_reserve_extent_cluster(root,
5671                                         block_group, search_start, num_bytes);
5672                                 goto checks;
5673                         }
5674
5675                         WARN_ON(last_ptr->block_group != used_block_group);
5676                         if (used_block_group != block_group) {
5677                                 btrfs_put_block_group(used_block_group);
5678                                 used_block_group = block_group;
5679                         }
5680 refill_cluster:
5681                         BUG_ON(used_block_group != block_group);
5682                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5683                          * set up a new clusters, so lets just skip it
5684                          * and let the allocator find whatever block
5685                          * it can find.  If we reach this point, we
5686                          * will have tried the cluster allocator
5687                          * plenty of times and not have found
5688                          * anything, so we are likely way too
5689                          * fragmented for the clustering stuff to find
5690                          * anything.
5691                          *
5692                          * However, if the cluster is taken from the
5693                          * current block group, release the cluster
5694                          * first, so that we stand a better chance of
5695                          * succeeding in the unclustered
5696                          * allocation.  */
5697                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5698                             last_ptr->block_group != block_group) {
5699                                 spin_unlock(&last_ptr->refill_lock);
5700                                 goto unclustered_alloc;
5701                         }
5702
5703                         /*
5704                          * this cluster didn't work out, free it and
5705                          * start over
5706                          */
5707                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5708
5709                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5710                                 spin_unlock(&last_ptr->refill_lock);
5711                                 goto unclustered_alloc;
5712                         }
5713
5714                         /* allocate a cluster in this block group */
5715                         ret = btrfs_find_space_cluster(trans, root,
5716                                                block_group, last_ptr,
5717                                                search_start, num_bytes,
5718                                                empty_cluster + empty_size);
5719                         if (ret == 0) {
5720                                 /*
5721                                  * now pull our allocation out of this
5722                                  * cluster
5723                                  */
5724                                 offset = btrfs_alloc_from_cluster(block_group,
5725                                                   last_ptr, num_bytes,
5726                                                   search_start);
5727                                 if (offset) {
5728                                         /* we found one, proceed */
5729                                         spin_unlock(&last_ptr->refill_lock);
5730                                         trace_btrfs_reserve_extent_cluster(root,
5731                                                 block_group, search_start,
5732                                                 num_bytes);
5733                                         goto checks;
5734                                 }
5735                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5736                                    && !failed_cluster_refill) {
5737                                 spin_unlock(&last_ptr->refill_lock);
5738
5739                                 failed_cluster_refill = true;
5740                                 wait_block_group_cache_progress(block_group,
5741                                        num_bytes + empty_cluster + empty_size);
5742                                 goto have_block_group;
5743                         }
5744
5745                         /*
5746                          * at this point we either didn't find a cluster
5747                          * or we weren't able to allocate a block from our
5748                          * cluster.  Free the cluster we've been trying
5749                          * to use, and go to the next block group
5750                          */
5751                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5752                         spin_unlock(&last_ptr->refill_lock);
5753                         goto loop;
5754                 }
5755
5756 unclustered_alloc:
5757                 spin_lock(&block_group->free_space_ctl->tree_lock);
5758                 if (cached &&
5759                     block_group->free_space_ctl->free_space <
5760                     num_bytes + empty_cluster + empty_size) {
5761                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5762                         goto loop;
5763                 }
5764                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5765
5766                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5767                                                     num_bytes, empty_size);
5768                 /*
5769                  * If we didn't find a chunk, and we haven't failed on this
5770                  * block group before, and this block group is in the middle of
5771                  * caching and we are ok with waiting, then go ahead and wait
5772                  * for progress to be made, and set failed_alloc to true.
5773                  *
5774                  * If failed_alloc is true then we've already waited on this
5775                  * block group once and should move on to the next block group.
5776                  */
5777                 if (!offset && !failed_alloc && !cached &&
5778                     loop > LOOP_CACHING_NOWAIT) {
5779                         wait_block_group_cache_progress(block_group,
5780                                                 num_bytes + empty_size);
5781                         failed_alloc = true;
5782                         goto have_block_group;
5783                 } else if (!offset) {
5784                         if (!cached)
5785                                 have_caching_bg = true;
5786                         goto loop;
5787                 }
5788 checks:
5789                 search_start = stripe_align(root, offset);
5790
5791                 /* move on to the next group */
5792                 if (search_start + num_bytes >
5793                     used_block_group->key.objectid + used_block_group->key.offset) {
5794                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5795                         goto loop;
5796                 }
5797
5798                 if (offset < search_start)
5799                         btrfs_add_free_space(used_block_group, offset,
5800                                              search_start - offset);
5801                 BUG_ON(offset > search_start);
5802
5803                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5804                                                   alloc_type);
5805                 if (ret == -EAGAIN) {
5806                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5807                         goto loop;
5808                 }
5809
5810                 /* we are all good, lets return */
5811                 ins->objectid = search_start;
5812                 ins->offset = num_bytes;
5813
5814                 trace_btrfs_reserve_extent(orig_root, block_group,
5815                                            search_start, num_bytes);
5816                 if (offset < search_start)
5817                         btrfs_add_free_space(used_block_group, offset,
5818                                              search_start - offset);
5819                 BUG_ON(offset > search_start);
5820                 if (used_block_group != block_group)
5821                         btrfs_put_block_group(used_block_group);
5822                 btrfs_put_block_group(block_group);
5823                 break;
5824 loop:
5825                 failed_cluster_refill = false;
5826                 failed_alloc = false;
5827                 BUG_ON(index != get_block_group_index(block_group));
5828                 if (used_block_group != block_group)
5829                         btrfs_put_block_group(used_block_group);
5830                 btrfs_put_block_group(block_group);
5831         }
5832         up_read(&space_info->groups_sem);
5833
5834         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5835                 goto search;
5836
5837         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5838                 goto search;
5839
5840         /*
5841          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5842          *                      caching kthreads as we move along
5843          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5844          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5845          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5846          *                      again
5847          */
5848         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5849                 index = 0;
5850                 loop++;
5851                 if (loop == LOOP_ALLOC_CHUNK) {
5852                        if (allowed_chunk_alloc) {
5853                                 ret = do_chunk_alloc(trans, root, num_bytes +
5854                                                      2 * 1024 * 1024, data,
5855                                                      CHUNK_ALLOC_LIMITED);
5856                                 /*
5857                                  * Do not bail out on ENOSPC since we
5858                                  * can do more things.
5859                                  */
5860                                 if (ret < 0 && ret != -ENOSPC) {
5861                                         btrfs_abort_transaction(trans,
5862                                                                 root, ret);
5863                                         goto out;
5864                                 }
5865                                 allowed_chunk_alloc = 0;
5866                                 if (ret == 1)
5867                                         done_chunk_alloc = 1;
5868                         } else if (!done_chunk_alloc &&
5869                                    space_info->force_alloc ==
5870                                    CHUNK_ALLOC_NO_FORCE) {
5871                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5872                         }
5873
5874                        /*
5875                         * We didn't allocate a chunk, go ahead and drop the
5876                         * empty size and loop again.
5877                         */
5878                        if (!done_chunk_alloc)
5879                                loop = LOOP_NO_EMPTY_SIZE;
5880                 }
5881
5882                 if (loop == LOOP_NO_EMPTY_SIZE) {
5883                         empty_size = 0;
5884                         empty_cluster = 0;
5885                 }
5886
5887                 goto search;
5888         } else if (!ins->objectid) {
5889                 ret = -ENOSPC;
5890         } else if (ins->objectid) {
5891                 ret = 0;
5892         }
5893 out:
5894
5895         return ret;
5896 }
5897
5898 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5899                             int dump_block_groups)
5900 {
5901         struct btrfs_block_group_cache *cache;
5902         int index = 0;
5903
5904         spin_lock(&info->lock);
5905         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5906                (unsigned long long)info->flags,
5907                (unsigned long long)(info->total_bytes - info->bytes_used -
5908                                     info->bytes_pinned - info->bytes_reserved -
5909                                     info->bytes_readonly),
5910                (info->full) ? "" : "not ");
5911         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5912                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5913                (unsigned long long)info->total_bytes,
5914                (unsigned long long)info->bytes_used,
5915                (unsigned long long)info->bytes_pinned,
5916                (unsigned long long)info->bytes_reserved,
5917                (unsigned long long)info->bytes_may_use,
5918                (unsigned long long)info->bytes_readonly);
5919         spin_unlock(&info->lock);
5920
5921         if (!dump_block_groups)
5922                 return;
5923
5924         down_read(&info->groups_sem);
5925 again:
5926         list_for_each_entry(cache, &info->block_groups[index], list) {
5927                 spin_lock(&cache->lock);
5928                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
5929                        (unsigned long long)cache->key.objectid,
5930                        (unsigned long long)cache->key.offset,
5931                        (unsigned long long)btrfs_block_group_used(&cache->item),
5932                        (unsigned long long)cache->pinned,
5933                        (unsigned long long)cache->reserved,
5934                        cache->ro ? "[readonly]" : "");
5935                 btrfs_dump_free_space(cache, bytes);
5936                 spin_unlock(&cache->lock);
5937         }
5938         if (++index < BTRFS_NR_RAID_TYPES)
5939                 goto again;
5940         up_read(&info->groups_sem);
5941 }
5942
5943 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5944                          struct btrfs_root *root,
5945                          u64 num_bytes, u64 min_alloc_size,
5946                          u64 empty_size, u64 hint_byte,
5947                          struct btrfs_key *ins, u64 data)
5948 {
5949         bool final_tried = false;
5950         int ret;
5951
5952         data = btrfs_get_alloc_profile(root, data);
5953 again:
5954         /*
5955          * the only place that sets empty_size is btrfs_realloc_node, which
5956          * is not called recursively on allocations
5957          */
5958         if (empty_size || root->ref_cows) {
5959                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5960                                      num_bytes + 2 * 1024 * 1024, data,
5961                                      CHUNK_ALLOC_NO_FORCE);
5962                 if (ret < 0 && ret != -ENOSPC) {
5963                         btrfs_abort_transaction(trans, root, ret);
5964                         return ret;
5965                 }
5966         }
5967
5968         WARN_ON(num_bytes < root->sectorsize);
5969         ret = find_free_extent(trans, root, num_bytes, empty_size,
5970                                hint_byte, ins, data);
5971
5972         if (ret == -ENOSPC) {
5973                 if (!final_tried) {
5974                         num_bytes = num_bytes >> 1;
5975                         num_bytes = num_bytes & ~(root->sectorsize - 1);
5976                         num_bytes = max(num_bytes, min_alloc_size);
5977                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5978                                        num_bytes, data, CHUNK_ALLOC_FORCE);
5979                         if (ret < 0 && ret != -ENOSPC) {
5980                                 btrfs_abort_transaction(trans, root, ret);
5981                                 return ret;
5982                         }
5983                         if (num_bytes == min_alloc_size)
5984                                 final_tried = true;
5985                         goto again;
5986                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
5987                         struct btrfs_space_info *sinfo;
5988
5989                         sinfo = __find_space_info(root->fs_info, data);
5990                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
5991                                "wanted %llu\n", (unsigned long long)data,
5992                                (unsigned long long)num_bytes);
5993                         if (sinfo)
5994                                 dump_space_info(sinfo, num_bytes, 1);
5995                 }
5996         }
5997
5998         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5999
6000         return ret;
6001 }
6002
6003 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6004                                         u64 start, u64 len, int pin)
6005 {
6006         struct btrfs_block_group_cache *cache;
6007         int ret = 0;
6008
6009         cache = btrfs_lookup_block_group(root->fs_info, start);
6010         if (!cache) {
6011                 printk(KERN_ERR "Unable to find block group for %llu\n",
6012                        (unsigned long long)start);
6013                 return -ENOSPC;
6014         }
6015
6016         if (btrfs_test_opt(root, DISCARD))
6017                 ret = btrfs_discard_extent(root, start, len, NULL);
6018
6019         if (pin)
6020                 pin_down_extent(root, cache, start, len, 1);
6021         else {
6022                 btrfs_add_free_space(cache, start, len);
6023                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6024         }
6025         btrfs_put_block_group(cache);
6026
6027         trace_btrfs_reserved_extent_free(root, start, len);
6028
6029         return ret;
6030 }
6031
6032 int btrfs_free_reserved_extent(struct btrfs_root *root,
6033                                         u64 start, u64 len)
6034 {
6035         return __btrfs_free_reserved_extent(root, start, len, 0);
6036 }
6037
6038 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6039                                        u64 start, u64 len)
6040 {
6041         return __btrfs_free_reserved_extent(root, start, len, 1);
6042 }
6043
6044 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6045                                       struct btrfs_root *root,
6046                                       u64 parent, u64 root_objectid,
6047                                       u64 flags, u64 owner, u64 offset,
6048                                       struct btrfs_key *ins, int ref_mod)
6049 {
6050         int ret;
6051         struct btrfs_fs_info *fs_info = root->fs_info;
6052         struct btrfs_extent_item *extent_item;
6053         struct btrfs_extent_inline_ref *iref;
6054         struct btrfs_path *path;
6055         struct extent_buffer *leaf;
6056         int type;
6057         u32 size;
6058
6059         if (parent > 0)
6060                 type = BTRFS_SHARED_DATA_REF_KEY;
6061         else
6062                 type = BTRFS_EXTENT_DATA_REF_KEY;
6063
6064         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6065
6066         path = btrfs_alloc_path();
6067         if (!path)
6068                 return -ENOMEM;
6069
6070         path->leave_spinning = 1;
6071         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6072                                       ins, size);
6073         if (ret) {
6074                 btrfs_free_path(path);
6075                 return ret;
6076         }
6077
6078         leaf = path->nodes[0];
6079         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6080                                      struct btrfs_extent_item);
6081         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6082         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6083         btrfs_set_extent_flags(leaf, extent_item,
6084                                flags | BTRFS_EXTENT_FLAG_DATA);
6085
6086         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6087         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6088         if (parent > 0) {
6089                 struct btrfs_shared_data_ref *ref;
6090                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6091                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6092                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6093         } else {
6094                 struct btrfs_extent_data_ref *ref;
6095                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6096                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6097                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6098                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6099                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6100         }
6101
6102         btrfs_mark_buffer_dirty(path->nodes[0]);
6103         btrfs_free_path(path);
6104
6105         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6106         if (ret) { /* -ENOENT, logic error */
6107                 printk(KERN_ERR "btrfs update block group failed for %llu "
6108                        "%llu\n", (unsigned long long)ins->objectid,
6109                        (unsigned long long)ins->offset);
6110                 BUG();
6111         }
6112         return ret;
6113 }
6114
6115 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6116                                      struct btrfs_root *root,
6117                                      u64 parent, u64 root_objectid,
6118                                      u64 flags, struct btrfs_disk_key *key,
6119                                      int level, struct btrfs_key *ins)
6120 {
6121         int ret;
6122         struct btrfs_fs_info *fs_info = root->fs_info;
6123         struct btrfs_extent_item *extent_item;
6124         struct btrfs_tree_block_info *block_info;
6125         struct btrfs_extent_inline_ref *iref;
6126         struct btrfs_path *path;
6127         struct extent_buffer *leaf;
6128         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
6129
6130         path = btrfs_alloc_path();
6131         if (!path)
6132                 return -ENOMEM;
6133
6134         path->leave_spinning = 1;
6135         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6136                                       ins, size);
6137         if (ret) {
6138                 btrfs_free_path(path);
6139                 return ret;
6140         }
6141
6142         leaf = path->nodes[0];
6143         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6144                                      struct btrfs_extent_item);
6145         btrfs_set_extent_refs(leaf, extent_item, 1);
6146         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6147         btrfs_set_extent_flags(leaf, extent_item,
6148                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6149         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6150
6151         btrfs_set_tree_block_key(leaf, block_info, key);
6152         btrfs_set_tree_block_level(leaf, block_info, level);
6153
6154         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6155         if (parent > 0) {
6156                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6157                 btrfs_set_extent_inline_ref_type(leaf, iref,
6158                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6159                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6160         } else {
6161                 btrfs_set_extent_inline_ref_type(leaf, iref,
6162                                                  BTRFS_TREE_BLOCK_REF_KEY);
6163                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6164         }
6165
6166         btrfs_mark_buffer_dirty(leaf);
6167         btrfs_free_path(path);
6168
6169         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6170         if (ret) { /* -ENOENT, logic error */
6171                 printk(KERN_ERR "btrfs update block group failed for %llu "
6172                        "%llu\n", (unsigned long long)ins->objectid,
6173                        (unsigned long long)ins->offset);
6174                 BUG();
6175         }
6176         return ret;
6177 }
6178
6179 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6180                                      struct btrfs_root *root,
6181                                      u64 root_objectid, u64 owner,
6182                                      u64 offset, struct btrfs_key *ins)
6183 {
6184         int ret;
6185
6186         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6187
6188         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6189                                          ins->offset, 0,
6190                                          root_objectid, owner, offset,
6191                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6192         return ret;
6193 }
6194
6195 /*
6196  * this is used by the tree logging recovery code.  It records that
6197  * an extent has been allocated and makes sure to clear the free
6198  * space cache bits as well
6199  */
6200 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6201                                    struct btrfs_root *root,
6202                                    u64 root_objectid, u64 owner, u64 offset,
6203                                    struct btrfs_key *ins)
6204 {
6205         int ret;
6206         struct btrfs_block_group_cache *block_group;
6207         struct btrfs_caching_control *caching_ctl;
6208         u64 start = ins->objectid;
6209         u64 num_bytes = ins->offset;
6210
6211         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6212         cache_block_group(block_group, trans, NULL, 0);
6213         caching_ctl = get_caching_control(block_group);
6214
6215         if (!caching_ctl) {
6216                 BUG_ON(!block_group_cache_done(block_group));
6217                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6218                 BUG_ON(ret); /* -ENOMEM */
6219         } else {
6220                 mutex_lock(&caching_ctl->mutex);
6221
6222                 if (start >= caching_ctl->progress) {
6223                         ret = add_excluded_extent(root, start, num_bytes);
6224                         BUG_ON(ret); /* -ENOMEM */
6225                 } else if (start + num_bytes <= caching_ctl->progress) {
6226                         ret = btrfs_remove_free_space(block_group,
6227                                                       start, num_bytes);
6228                         BUG_ON(ret); /* -ENOMEM */
6229                 } else {
6230                         num_bytes = caching_ctl->progress - start;
6231                         ret = btrfs_remove_free_space(block_group,
6232                                                       start, num_bytes);
6233                         BUG_ON(ret); /* -ENOMEM */
6234
6235                         start = caching_ctl->progress;
6236                         num_bytes = ins->objectid + ins->offset -
6237                                     caching_ctl->progress;
6238                         ret = add_excluded_extent(root, start, num_bytes);
6239                         BUG_ON(ret); /* -ENOMEM */
6240                 }
6241
6242                 mutex_unlock(&caching_ctl->mutex);
6243                 put_caching_control(caching_ctl);
6244         }
6245
6246         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6247                                           RESERVE_ALLOC_NO_ACCOUNT);
6248         BUG_ON(ret); /* logic error */
6249         btrfs_put_block_group(block_group);
6250         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6251                                          0, owner, offset, ins, 1);
6252         return ret;
6253 }
6254
6255 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6256                                             struct btrfs_root *root,
6257                                             u64 bytenr, u32 blocksize,
6258                                             int level)
6259 {
6260         struct extent_buffer *buf;
6261
6262         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6263         if (!buf)
6264                 return ERR_PTR(-ENOMEM);
6265         btrfs_set_header_generation(buf, trans->transid);
6266         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6267         btrfs_tree_lock(buf);
6268         clean_tree_block(trans, root, buf);
6269         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6270
6271         btrfs_set_lock_blocking(buf);
6272         btrfs_set_buffer_uptodate(buf);
6273
6274         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6275                 /*
6276                  * we allow two log transactions at a time, use different
6277                  * EXENT bit to differentiate dirty pages.
6278                  */
6279                 if (root->log_transid % 2 == 0)
6280                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6281                                         buf->start + buf->len - 1, GFP_NOFS);
6282                 else
6283                         set_extent_new(&root->dirty_log_pages, buf->start,
6284                                         buf->start + buf->len - 1, GFP_NOFS);
6285         } else {
6286                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6287                          buf->start + buf->len - 1, GFP_NOFS);
6288         }
6289         trans->blocks_used++;
6290         /* this returns a buffer locked for blocking */
6291         return buf;
6292 }
6293
6294 static struct btrfs_block_rsv *
6295 use_block_rsv(struct btrfs_trans_handle *trans,
6296               struct btrfs_root *root, u32 blocksize)
6297 {
6298         struct btrfs_block_rsv *block_rsv;
6299         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6300         int ret;
6301
6302         block_rsv = get_block_rsv(trans, root);
6303
6304         if (block_rsv->size == 0) {
6305                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6306                 /*
6307                  * If we couldn't reserve metadata bytes try and use some from
6308                  * the global reserve.
6309                  */
6310                 if (ret && block_rsv != global_rsv) {
6311                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6312                         if (!ret)
6313                                 return global_rsv;
6314                         return ERR_PTR(ret);
6315                 } else if (ret) {
6316                         return ERR_PTR(ret);
6317                 }
6318                 return block_rsv;
6319         }
6320
6321         ret = block_rsv_use_bytes(block_rsv, blocksize);
6322         if (!ret)
6323                 return block_rsv;
6324         if (ret) {
6325                 static DEFINE_RATELIMIT_STATE(_rs,
6326                                 DEFAULT_RATELIMIT_INTERVAL,
6327                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6328                 if (__ratelimit(&_rs)) {
6329                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6330                         WARN_ON(1);
6331                 }
6332                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6333                 if (!ret) {
6334                         return block_rsv;
6335                 } else if (ret && block_rsv != global_rsv) {
6336                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6337                         if (!ret)
6338                                 return global_rsv;
6339                 }
6340         }
6341
6342         return ERR_PTR(-ENOSPC);
6343 }
6344
6345 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6346                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6347 {
6348         block_rsv_add_bytes(block_rsv, blocksize, 0);
6349         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6350 }
6351
6352 /*
6353  * finds a free extent and does all the dirty work required for allocation
6354  * returns the key for the extent through ins, and a tree buffer for
6355  * the first block of the extent through buf.
6356  *
6357  * returns the tree buffer or NULL.
6358  */
6359 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6360                                         struct btrfs_root *root, u32 blocksize,
6361                                         u64 parent, u64 root_objectid,
6362                                         struct btrfs_disk_key *key, int level,
6363                                         u64 hint, u64 empty_size)
6364 {
6365         struct btrfs_key ins;
6366         struct btrfs_block_rsv *block_rsv;
6367         struct extent_buffer *buf;
6368         u64 flags = 0;
6369         int ret;
6370
6371
6372         block_rsv = use_block_rsv(trans, root, blocksize);
6373         if (IS_ERR(block_rsv))
6374                 return ERR_CAST(block_rsv);
6375
6376         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6377                                    empty_size, hint, &ins, 0);
6378         if (ret) {
6379                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6380                 return ERR_PTR(ret);
6381         }
6382
6383         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6384                                     blocksize, level);
6385         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6386
6387         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6388                 if (parent == 0)
6389                         parent = ins.objectid;
6390                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6391         } else
6392                 BUG_ON(parent > 0);
6393
6394         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6395                 struct btrfs_delayed_extent_op *extent_op;
6396                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6397                 BUG_ON(!extent_op); /* -ENOMEM */
6398                 if (key)
6399                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6400                 else
6401                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6402                 extent_op->flags_to_set = flags;
6403                 extent_op->update_key = 1;
6404                 extent_op->update_flags = 1;
6405                 extent_op->is_data = 0;
6406
6407                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6408                                         ins.objectid,
6409                                         ins.offset, parent, root_objectid,
6410                                         level, BTRFS_ADD_DELAYED_EXTENT,
6411                                         extent_op, 0);
6412                 BUG_ON(ret); /* -ENOMEM */
6413         }
6414         return buf;
6415 }
6416
6417 struct walk_control {
6418         u64 refs[BTRFS_MAX_LEVEL];
6419         u64 flags[BTRFS_MAX_LEVEL];
6420         struct btrfs_key update_progress;
6421         int stage;
6422         int level;
6423         int shared_level;
6424         int update_ref;
6425         int keep_locks;
6426         int reada_slot;
6427         int reada_count;
6428         int for_reloc;
6429 };
6430
6431 #define DROP_REFERENCE  1
6432 #define UPDATE_BACKREF  2
6433
6434 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6435                                      struct btrfs_root *root,
6436                                      struct walk_control *wc,
6437                                      struct btrfs_path *path)
6438 {
6439         u64 bytenr;
6440         u64 generation;
6441         u64 refs;
6442         u64 flags;
6443         u32 nritems;
6444         u32 blocksize;
6445         struct btrfs_key key;
6446         struct extent_buffer *eb;
6447         int ret;
6448         int slot;
6449         int nread = 0;
6450
6451         if (path->slots[wc->level] < wc->reada_slot) {
6452                 wc->reada_count = wc->reada_count * 2 / 3;
6453                 wc->reada_count = max(wc->reada_count, 2);
6454         } else {
6455                 wc->reada_count = wc->reada_count * 3 / 2;
6456                 wc->reada_count = min_t(int, wc->reada_count,
6457                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6458         }
6459
6460         eb = path->nodes[wc->level];
6461         nritems = btrfs_header_nritems(eb);
6462         blocksize = btrfs_level_size(root, wc->level - 1);
6463
6464         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6465                 if (nread >= wc->reada_count)
6466                         break;
6467
6468                 cond_resched();
6469                 bytenr = btrfs_node_blockptr(eb, slot);
6470                 generation = btrfs_node_ptr_generation(eb, slot);
6471
6472                 if (slot == path->slots[wc->level])
6473                         goto reada;
6474
6475                 if (wc->stage == UPDATE_BACKREF &&
6476                     generation <= root->root_key.offset)
6477                         continue;
6478
6479                 /* We don't lock the tree block, it's OK to be racy here */
6480                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6481                                                &refs, &flags);
6482                 /* We don't care about errors in readahead. */
6483                 if (ret < 0)
6484                         continue;
6485                 BUG_ON(refs == 0);
6486
6487                 if (wc->stage == DROP_REFERENCE) {
6488                         if (refs == 1)
6489                                 goto reada;
6490
6491                         if (wc->level == 1 &&
6492                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6493                                 continue;
6494                         if (!wc->update_ref ||
6495                             generation <= root->root_key.offset)
6496                                 continue;
6497                         btrfs_node_key_to_cpu(eb, &key, slot);
6498                         ret = btrfs_comp_cpu_keys(&key,
6499                                                   &wc->update_progress);
6500                         if (ret < 0)
6501                                 continue;
6502                 } else {
6503                         if (wc->level == 1 &&
6504                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6505                                 continue;
6506                 }
6507 reada:
6508                 ret = readahead_tree_block(root, bytenr, blocksize,
6509                                            generation);
6510                 if (ret)
6511                         break;
6512                 nread++;
6513         }
6514         wc->reada_slot = slot;
6515 }
6516
6517 /*
6518  * hepler to process tree block while walking down the tree.
6519  *
6520  * when wc->stage == UPDATE_BACKREF, this function updates
6521  * back refs for pointers in the block.
6522  *
6523  * NOTE: return value 1 means we should stop walking down.
6524  */
6525 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6526                                    struct btrfs_root *root,
6527                                    struct btrfs_path *path,
6528                                    struct walk_control *wc, int lookup_info)
6529 {
6530         int level = wc->level;
6531         struct extent_buffer *eb = path->nodes[level];
6532         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6533         int ret;
6534
6535         if (wc->stage == UPDATE_BACKREF &&
6536             btrfs_header_owner(eb) != root->root_key.objectid)
6537                 return 1;
6538
6539         /*
6540          * when reference count of tree block is 1, it won't increase
6541          * again. once full backref flag is set, we never clear it.
6542          */
6543         if (lookup_info &&
6544             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6545              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6546                 BUG_ON(!path->locks[level]);
6547                 ret = btrfs_lookup_extent_info(trans, root,
6548                                                eb->start, eb->len,
6549                                                &wc->refs[level],
6550                                                &wc->flags[level]);
6551                 BUG_ON(ret == -ENOMEM);
6552                 if (ret)
6553                         return ret;
6554                 BUG_ON(wc->refs[level] == 0);
6555         }
6556
6557         if (wc->stage == DROP_REFERENCE) {
6558                 if (wc->refs[level] > 1)
6559                         return 1;
6560
6561                 if (path->locks[level] && !wc->keep_locks) {
6562                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6563                         path->locks[level] = 0;
6564                 }
6565                 return 0;
6566         }
6567
6568         /* wc->stage == UPDATE_BACKREF */
6569         if (!(wc->flags[level] & flag)) {
6570                 BUG_ON(!path->locks[level]);
6571                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6572                 BUG_ON(ret); /* -ENOMEM */
6573                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6574                 BUG_ON(ret); /* -ENOMEM */
6575                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6576                                                   eb->len, flag, 0);
6577                 BUG_ON(ret); /* -ENOMEM */
6578                 wc->flags[level] |= flag;
6579         }
6580
6581         /*
6582          * the block is shared by multiple trees, so it's not good to
6583          * keep the tree lock
6584          */
6585         if (path->locks[level] && level > 0) {
6586                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6587                 path->locks[level] = 0;
6588         }
6589         return 0;
6590 }
6591
6592 /*
6593  * hepler to process tree block pointer.
6594  *
6595  * when wc->stage == DROP_REFERENCE, this function checks
6596  * reference count of the block pointed to. if the block
6597  * is shared and we need update back refs for the subtree
6598  * rooted at the block, this function changes wc->stage to
6599  * UPDATE_BACKREF. if the block is shared and there is no
6600  * need to update back, this function drops the reference
6601  * to the block.
6602  *
6603  * NOTE: return value 1 means we should stop walking down.
6604  */
6605 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6606                                  struct btrfs_root *root,
6607                                  struct btrfs_path *path,
6608                                  struct walk_control *wc, int *lookup_info)
6609 {
6610         u64 bytenr;
6611         u64 generation;
6612         u64 parent;
6613         u32 blocksize;
6614         struct btrfs_key key;
6615         struct extent_buffer *next;
6616         int level = wc->level;
6617         int reada = 0;
6618         int ret = 0;
6619
6620         generation = btrfs_node_ptr_generation(path->nodes[level],
6621                                                path->slots[level]);
6622         /*
6623          * if the lower level block was created before the snapshot
6624          * was created, we know there is no need to update back refs
6625          * for the subtree
6626          */
6627         if (wc->stage == UPDATE_BACKREF &&
6628             generation <= root->root_key.offset) {
6629                 *lookup_info = 1;
6630                 return 1;
6631         }
6632
6633         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6634         blocksize = btrfs_level_size(root, level - 1);
6635
6636         next = btrfs_find_tree_block(root, bytenr, blocksize);
6637         if (!next) {
6638                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6639                 if (!next)
6640                         return -ENOMEM;
6641                 reada = 1;
6642         }
6643         btrfs_tree_lock(next);
6644         btrfs_set_lock_blocking(next);
6645
6646         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6647                                        &wc->refs[level - 1],
6648                                        &wc->flags[level - 1]);
6649         if (ret < 0) {
6650                 btrfs_tree_unlock(next);
6651                 return ret;
6652         }
6653
6654         BUG_ON(wc->refs[level - 1] == 0);
6655         *lookup_info = 0;
6656
6657         if (wc->stage == DROP_REFERENCE) {
6658                 if (wc->refs[level - 1] > 1) {
6659                         if (level == 1 &&
6660                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6661                                 goto skip;
6662
6663                         if (!wc->update_ref ||
6664                             generation <= root->root_key.offset)
6665                                 goto skip;
6666
6667                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6668                                               path->slots[level]);
6669                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6670                         if (ret < 0)
6671                                 goto skip;
6672
6673                         wc->stage = UPDATE_BACKREF;
6674                         wc->shared_level = level - 1;
6675                 }
6676         } else {
6677                 if (level == 1 &&
6678                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6679                         goto skip;
6680         }
6681
6682         if (!btrfs_buffer_uptodate(next, generation, 0)) {
6683                 btrfs_tree_unlock(next);
6684                 free_extent_buffer(next);
6685                 next = NULL;
6686                 *lookup_info = 1;
6687         }
6688
6689         if (!next) {
6690                 if (reada && level == 1)
6691                         reada_walk_down(trans, root, wc, path);
6692                 next = read_tree_block(root, bytenr, blocksize, generation);
6693                 if (!next)
6694                         return -EIO;
6695                 btrfs_tree_lock(next);
6696                 btrfs_set_lock_blocking(next);
6697         }
6698
6699         level--;
6700         BUG_ON(level != btrfs_header_level(next));
6701         path->nodes[level] = next;
6702         path->slots[level] = 0;
6703         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6704         wc->level = level;
6705         if (wc->level == 1)
6706                 wc->reada_slot = 0;
6707         return 0;
6708 skip:
6709         wc->refs[level - 1] = 0;
6710         wc->flags[level - 1] = 0;
6711         if (wc->stage == DROP_REFERENCE) {
6712                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6713                         parent = path->nodes[level]->start;
6714                 } else {
6715                         BUG_ON(root->root_key.objectid !=
6716                                btrfs_header_owner(path->nodes[level]));
6717                         parent = 0;
6718                 }
6719
6720                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6721                                 root->root_key.objectid, level - 1, 0, 0);
6722                 BUG_ON(ret); /* -ENOMEM */
6723         }
6724         btrfs_tree_unlock(next);
6725         free_extent_buffer(next);
6726         *lookup_info = 1;
6727         return 1;
6728 }
6729
6730 /*
6731  * hepler to process tree block while walking up the tree.
6732  *
6733  * when wc->stage == DROP_REFERENCE, this function drops
6734  * reference count on the block.
6735  *
6736  * when wc->stage == UPDATE_BACKREF, this function changes
6737  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6738  * to UPDATE_BACKREF previously while processing the block.
6739  *
6740  * NOTE: return value 1 means we should stop walking up.
6741  */
6742 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6743                                  struct btrfs_root *root,
6744                                  struct btrfs_path *path,
6745                                  struct walk_control *wc)
6746 {
6747         int ret;
6748         int level = wc->level;
6749         struct extent_buffer *eb = path->nodes[level];
6750         u64 parent = 0;
6751
6752         if (wc->stage == UPDATE_BACKREF) {
6753                 BUG_ON(wc->shared_level < level);
6754                 if (level < wc->shared_level)
6755                         goto out;
6756
6757                 ret = find_next_key(path, level + 1, &wc->update_progress);
6758                 if (ret > 0)
6759                         wc->update_ref = 0;
6760
6761                 wc->stage = DROP_REFERENCE;
6762                 wc->shared_level = -1;
6763                 path->slots[level] = 0;
6764
6765                 /*
6766                  * check reference count again if the block isn't locked.
6767                  * we should start walking down the tree again if reference
6768                  * count is one.
6769                  */
6770                 if (!path->locks[level]) {
6771                         BUG_ON(level == 0);
6772                         btrfs_tree_lock(eb);
6773                         btrfs_set_lock_blocking(eb);
6774                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6775
6776                         ret = btrfs_lookup_extent_info(trans, root,
6777                                                        eb->start, eb->len,
6778                                                        &wc->refs[level],
6779                                                        &wc->flags[level]);
6780                         if (ret < 0) {
6781                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6782                                 return ret;
6783                         }
6784                         BUG_ON(wc->refs[level] == 0);
6785                         if (wc->refs[level] == 1) {
6786                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6787                                 return 1;
6788                         }
6789                 }
6790         }
6791
6792         /* wc->stage == DROP_REFERENCE */
6793         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6794
6795         if (wc->refs[level] == 1) {
6796                 if (level == 0) {
6797                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6798                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6799                                                     wc->for_reloc);
6800                         else
6801                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6802                                                     wc->for_reloc);
6803                         BUG_ON(ret); /* -ENOMEM */
6804                 }
6805                 /* make block locked assertion in clean_tree_block happy */
6806                 if (!path->locks[level] &&
6807                     btrfs_header_generation(eb) == trans->transid) {
6808                         btrfs_tree_lock(eb);
6809                         btrfs_set_lock_blocking(eb);
6810                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6811                 }
6812                 clean_tree_block(trans, root, eb);
6813         }
6814
6815         if (eb == root->node) {
6816                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6817                         parent = eb->start;
6818                 else
6819                         BUG_ON(root->root_key.objectid !=
6820                                btrfs_header_owner(eb));
6821         } else {
6822                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6823                         parent = path->nodes[level + 1]->start;
6824                 else
6825                         BUG_ON(root->root_key.objectid !=
6826                                btrfs_header_owner(path->nodes[level + 1]));
6827         }
6828
6829         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6830 out:
6831         wc->refs[level] = 0;
6832         wc->flags[level] = 0;
6833         return 0;
6834 }
6835
6836 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6837                                    struct btrfs_root *root,
6838                                    struct btrfs_path *path,
6839                                    struct walk_control *wc)
6840 {
6841         int level = wc->level;
6842         int lookup_info = 1;
6843         int ret;
6844
6845         while (level >= 0) {
6846                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6847                 if (ret > 0)
6848                         break;
6849
6850                 if (level == 0)
6851                         break;
6852
6853                 if (path->slots[level] >=
6854                     btrfs_header_nritems(path->nodes[level]))
6855                         break;
6856
6857                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6858                 if (ret > 0) {
6859                         path->slots[level]++;
6860                         continue;
6861                 } else if (ret < 0)
6862                         return ret;
6863                 level = wc->level;
6864         }
6865         return 0;
6866 }
6867
6868 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6869                                  struct btrfs_root *root,
6870                                  struct btrfs_path *path,
6871                                  struct walk_control *wc, int max_level)
6872 {
6873         int level = wc->level;
6874         int ret;
6875
6876         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6877         while (level < max_level && path->nodes[level]) {
6878                 wc->level = level;
6879                 if (path->slots[level] + 1 <
6880                     btrfs_header_nritems(path->nodes[level])) {
6881                         path->slots[level]++;
6882                         return 0;
6883                 } else {
6884                         ret = walk_up_proc(trans, root, path, wc);
6885                         if (ret > 0)
6886                                 return 0;
6887
6888                         if (path->locks[level]) {
6889                                 btrfs_tree_unlock_rw(path->nodes[level],
6890                                                      path->locks[level]);
6891                                 path->locks[level] = 0;
6892                         }
6893                         free_extent_buffer(path->nodes[level]);
6894                         path->nodes[level] = NULL;
6895                         level++;
6896                 }
6897         }
6898         return 1;
6899 }
6900
6901 /*
6902  * drop a subvolume tree.
6903  *
6904  * this function traverses the tree freeing any blocks that only
6905  * referenced by the tree.
6906  *
6907  * when a shared tree block is found. this function decreases its
6908  * reference count by one. if update_ref is true, this function
6909  * also make sure backrefs for the shared block and all lower level
6910  * blocks are properly updated.
6911  */
6912 int btrfs_drop_snapshot(struct btrfs_root *root,
6913                          struct btrfs_block_rsv *block_rsv, int update_ref,
6914                          int for_reloc)
6915 {
6916         struct btrfs_path *path;
6917         struct btrfs_trans_handle *trans;
6918         struct btrfs_root *tree_root = root->fs_info->tree_root;
6919         struct btrfs_root_item *root_item = &root->root_item;
6920         struct walk_control *wc;
6921         struct btrfs_key key;
6922         int err = 0;
6923         int ret;
6924         int level;
6925
6926         path = btrfs_alloc_path();
6927         if (!path) {
6928                 err = -ENOMEM;
6929                 goto out;
6930         }
6931
6932         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6933         if (!wc) {
6934                 btrfs_free_path(path);
6935                 err = -ENOMEM;
6936                 goto out;
6937         }
6938
6939         trans = btrfs_start_transaction(tree_root, 0);
6940         if (IS_ERR(trans)) {
6941                 err = PTR_ERR(trans);
6942                 goto out_free;
6943         }
6944
6945         if (block_rsv)
6946                 trans->block_rsv = block_rsv;
6947
6948         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6949                 level = btrfs_header_level(root->node);
6950                 path->nodes[level] = btrfs_lock_root_node(root);
6951                 btrfs_set_lock_blocking(path->nodes[level]);
6952                 path->slots[level] = 0;
6953                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6954                 memset(&wc->update_progress, 0,
6955                        sizeof(wc->update_progress));
6956         } else {
6957                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6958                 memcpy(&wc->update_progress, &key,
6959                        sizeof(wc->update_progress));
6960
6961                 level = root_item->drop_level;
6962                 BUG_ON(level == 0);
6963                 path->lowest_level = level;
6964                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6965                 path->lowest_level = 0;
6966                 if (ret < 0) {
6967                         err = ret;
6968                         goto out_end_trans;
6969                 }
6970                 WARN_ON(ret > 0);
6971
6972                 /*
6973                  * unlock our path, this is safe because only this
6974                  * function is allowed to delete this snapshot
6975                  */
6976                 btrfs_unlock_up_safe(path, 0);
6977
6978                 level = btrfs_header_level(root->node);
6979                 while (1) {
6980                         btrfs_tree_lock(path->nodes[level]);
6981                         btrfs_set_lock_blocking(path->nodes[level]);
6982
6983                         ret = btrfs_lookup_extent_info(trans, root,
6984                                                 path->nodes[level]->start,
6985                                                 path->nodes[level]->len,
6986                                                 &wc->refs[level],
6987                                                 &wc->flags[level]);
6988                         if (ret < 0) {
6989                                 err = ret;
6990                                 goto out_end_trans;
6991                         }
6992                         BUG_ON(wc->refs[level] == 0);
6993
6994                         if (level == root_item->drop_level)
6995                                 break;
6996
6997                         btrfs_tree_unlock(path->nodes[level]);
6998                         WARN_ON(wc->refs[level] != 1);
6999                         level--;
7000                 }
7001         }
7002
7003         wc->level = level;
7004         wc->shared_level = -1;
7005         wc->stage = DROP_REFERENCE;
7006         wc->update_ref = update_ref;
7007         wc->keep_locks = 0;
7008         wc->for_reloc = for_reloc;
7009         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7010
7011         while (1) {
7012                 ret = walk_down_tree(trans, root, path, wc);
7013                 if (ret < 0) {
7014                         err = ret;
7015                         break;
7016                 }
7017
7018                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7019                 if (ret < 0) {
7020                         err = ret;
7021                         break;
7022                 }
7023
7024                 if (ret > 0) {
7025                         BUG_ON(wc->stage != DROP_REFERENCE);
7026                         break;
7027                 }
7028
7029                 if (wc->stage == DROP_REFERENCE) {
7030                         level = wc->level;
7031                         btrfs_node_key(path->nodes[level],
7032                                        &root_item->drop_progress,
7033                                        path->slots[level]);
7034                         root_item->drop_level = level;
7035                 }
7036
7037                 BUG_ON(wc->level == 0);
7038                 if (btrfs_should_end_transaction(trans, tree_root)) {
7039                         ret = btrfs_update_root(trans, tree_root,
7040                                                 &root->root_key,
7041                                                 root_item);
7042                         if (ret) {
7043                                 btrfs_abort_transaction(trans, tree_root, ret);
7044                                 err = ret;
7045                                 goto out_end_trans;
7046                         }
7047
7048                         btrfs_end_transaction_throttle(trans, tree_root);
7049                         trans = btrfs_start_transaction(tree_root, 0);
7050                         if (IS_ERR(trans)) {
7051                                 err = PTR_ERR(trans);
7052                                 goto out_free;
7053                         }
7054                         if (block_rsv)
7055                                 trans->block_rsv = block_rsv;
7056                 }
7057         }
7058         btrfs_release_path(path);
7059         if (err)
7060                 goto out_end_trans;
7061
7062         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7063         if (ret) {
7064                 btrfs_abort_transaction(trans, tree_root, ret);
7065                 goto out_end_trans;
7066         }
7067
7068         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7069                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
7070                                            NULL, NULL);
7071                 if (ret < 0) {
7072                         btrfs_abort_transaction(trans, tree_root, ret);
7073                         err = ret;
7074                         goto out_end_trans;
7075                 } else if (ret > 0) {
7076                         /* if we fail to delete the orphan item this time
7077                          * around, it'll get picked up the next time.
7078                          *
7079                          * The most common failure here is just -ENOENT.
7080                          */
7081                         btrfs_del_orphan_item(trans, tree_root,
7082                                               root->root_key.objectid);
7083                 }
7084         }
7085
7086         if (root->in_radix) {
7087                 btrfs_free_fs_root(tree_root->fs_info, root);
7088         } else {
7089                 free_extent_buffer(root->node);
7090                 free_extent_buffer(root->commit_root);
7091                 kfree(root);
7092         }
7093 out_end_trans:
7094         btrfs_end_transaction_throttle(trans, tree_root);
7095 out_free:
7096         kfree(wc);
7097         btrfs_free_path(path);
7098 out:
7099         if (err)
7100                 btrfs_std_error(root->fs_info, err);
7101         return err;
7102 }
7103
7104 /*
7105  * drop subtree rooted at tree block 'node'.
7106  *
7107  * NOTE: this function will unlock and release tree block 'node'
7108  * only used by relocation code
7109  */
7110 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7111                         struct btrfs_root *root,
7112                         struct extent_buffer *node,
7113                         struct extent_buffer *parent)
7114 {
7115         struct btrfs_path *path;
7116         struct walk_control *wc;
7117         int level;
7118         int parent_level;
7119         int ret = 0;
7120         int wret;
7121
7122         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7123
7124         path = btrfs_alloc_path();
7125         if (!path)
7126                 return -ENOMEM;
7127
7128         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7129         if (!wc) {
7130                 btrfs_free_path(path);
7131                 return -ENOMEM;
7132         }
7133
7134         btrfs_assert_tree_locked(parent);
7135         parent_level = btrfs_header_level(parent);
7136         extent_buffer_get(parent);
7137         path->nodes[parent_level] = parent;
7138         path->slots[parent_level] = btrfs_header_nritems(parent);
7139
7140         btrfs_assert_tree_locked(node);
7141         level = btrfs_header_level(node);
7142         path->nodes[level] = node;
7143         path->slots[level] = 0;
7144         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7145
7146         wc->refs[parent_level] = 1;
7147         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7148         wc->level = level;
7149         wc->shared_level = -1;
7150         wc->stage = DROP_REFERENCE;
7151         wc->update_ref = 0;
7152         wc->keep_locks = 1;
7153         wc->for_reloc = 1;
7154         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7155
7156         while (1) {
7157                 wret = walk_down_tree(trans, root, path, wc);
7158                 if (wret < 0) {
7159                         ret = wret;
7160                         break;
7161                 }
7162
7163                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7164                 if (wret < 0)
7165                         ret = wret;
7166                 if (wret != 0)
7167                         break;
7168         }
7169
7170         kfree(wc);
7171         btrfs_free_path(path);
7172         return ret;
7173 }
7174
7175 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7176 {
7177         u64 num_devices;
7178         u64 stripped;
7179
7180         /*
7181          * if restripe for this chunk_type is on pick target profile and
7182          * return, otherwise do the usual balance
7183          */
7184         stripped = get_restripe_target(root->fs_info, flags);
7185         if (stripped)
7186                 return extended_to_chunk(stripped);
7187
7188         /*
7189          * we add in the count of missing devices because we want
7190          * to make sure that any RAID levels on a degraded FS
7191          * continue to be honored.
7192          */
7193         num_devices = root->fs_info->fs_devices->rw_devices +
7194                 root->fs_info->fs_devices->missing_devices;
7195
7196         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7197                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7198
7199         if (num_devices == 1) {
7200                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7201                 stripped = flags & ~stripped;
7202
7203                 /* turn raid0 into single device chunks */
7204                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7205                         return stripped;
7206
7207                 /* turn mirroring into duplication */
7208                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7209                              BTRFS_BLOCK_GROUP_RAID10))
7210                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7211         } else {
7212                 /* they already had raid on here, just return */
7213                 if (flags & stripped)
7214                         return flags;
7215
7216                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7217                 stripped = flags & ~stripped;
7218
7219                 /* switch duplicated blocks with raid1 */
7220                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7221                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7222
7223                 /* this is drive concat, leave it alone */
7224         }
7225
7226         return flags;
7227 }
7228
7229 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7230 {
7231         struct btrfs_space_info *sinfo = cache->space_info;
7232         u64 num_bytes;
7233         u64 min_allocable_bytes;
7234         int ret = -ENOSPC;
7235
7236
7237         /*
7238          * We need some metadata space and system metadata space for
7239          * allocating chunks in some corner cases until we force to set
7240          * it to be readonly.
7241          */
7242         if ((sinfo->flags &
7243              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7244             !force)
7245                 min_allocable_bytes = 1 * 1024 * 1024;
7246         else
7247                 min_allocable_bytes = 0;
7248
7249         spin_lock(&sinfo->lock);
7250         spin_lock(&cache->lock);
7251
7252         if (cache->ro) {
7253                 ret = 0;
7254                 goto out;
7255         }
7256
7257         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7258                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7259
7260         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7261             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7262             min_allocable_bytes <= sinfo->total_bytes) {
7263                 sinfo->bytes_readonly += num_bytes;
7264                 cache->ro = 1;
7265                 ret = 0;
7266         }
7267 out:
7268         spin_unlock(&cache->lock);
7269         spin_unlock(&sinfo->lock);
7270         return ret;
7271 }
7272
7273 int btrfs_set_block_group_ro(struct btrfs_root *root,
7274                              struct btrfs_block_group_cache *cache)
7275
7276 {
7277         struct btrfs_trans_handle *trans;
7278         u64 alloc_flags;
7279         int ret;
7280
7281         BUG_ON(cache->ro);
7282
7283         trans = btrfs_join_transaction(root);
7284         if (IS_ERR(trans))
7285                 return PTR_ERR(trans);
7286
7287         alloc_flags = update_block_group_flags(root, cache->flags);
7288         if (alloc_flags != cache->flags) {
7289                 ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7290                                      CHUNK_ALLOC_FORCE);
7291                 if (ret < 0)
7292                         goto out;
7293         }
7294
7295         ret = set_block_group_ro(cache, 0);
7296         if (!ret)
7297                 goto out;
7298         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7299         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7300                              CHUNK_ALLOC_FORCE);
7301         if (ret < 0)
7302                 goto out;
7303         ret = set_block_group_ro(cache, 0);
7304 out:
7305         btrfs_end_transaction(trans, root);
7306         return ret;
7307 }
7308
7309 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7310                             struct btrfs_root *root, u64 type)
7311 {
7312         u64 alloc_flags = get_alloc_profile(root, type);
7313         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7314                               CHUNK_ALLOC_FORCE);
7315 }
7316
7317 /*
7318  * helper to account the unused space of all the readonly block group in the
7319  * list. takes mirrors into account.
7320  */
7321 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7322 {
7323         struct btrfs_block_group_cache *block_group;
7324         u64 free_bytes = 0;
7325         int factor;
7326
7327         list_for_each_entry(block_group, groups_list, list) {
7328                 spin_lock(&block_group->lock);
7329
7330                 if (!block_group->ro) {
7331                         spin_unlock(&block_group->lock);
7332                         continue;
7333                 }
7334
7335                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7336                                           BTRFS_BLOCK_GROUP_RAID10 |
7337                                           BTRFS_BLOCK_GROUP_DUP))
7338                         factor = 2;
7339                 else
7340                         factor = 1;
7341
7342                 free_bytes += (block_group->key.offset -
7343                                btrfs_block_group_used(&block_group->item)) *
7344                                factor;
7345
7346                 spin_unlock(&block_group->lock);
7347         }
7348
7349         return free_bytes;
7350 }
7351
7352 /*
7353  * helper to account the unused space of all the readonly block group in the
7354  * space_info. takes mirrors into account.
7355  */
7356 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7357 {
7358         int i;
7359         u64 free_bytes = 0;
7360
7361         spin_lock(&sinfo->lock);
7362
7363         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7364                 if (!list_empty(&sinfo->block_groups[i]))
7365                         free_bytes += __btrfs_get_ro_block_group_free_space(
7366                                                 &sinfo->block_groups[i]);
7367
7368         spin_unlock(&sinfo->lock);
7369
7370         return free_bytes;
7371 }
7372
7373 void btrfs_set_block_group_rw(struct btrfs_root *root,
7374                               struct btrfs_block_group_cache *cache)
7375 {
7376         struct btrfs_space_info *sinfo = cache->space_info;
7377         u64 num_bytes;
7378
7379         BUG_ON(!cache->ro);
7380
7381         spin_lock(&sinfo->lock);
7382         spin_lock(&cache->lock);
7383         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7384                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7385         sinfo->bytes_readonly -= num_bytes;
7386         cache->ro = 0;
7387         spin_unlock(&cache->lock);
7388         spin_unlock(&sinfo->lock);
7389 }
7390
7391 /*
7392  * checks to see if its even possible to relocate this block group.
7393  *
7394  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7395  * ok to go ahead and try.
7396  */
7397 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7398 {
7399         struct btrfs_block_group_cache *block_group;
7400         struct btrfs_space_info *space_info;
7401         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7402         struct btrfs_device *device;
7403         u64 min_free;
7404         u64 dev_min = 1;
7405         u64 dev_nr = 0;
7406         u64 target;
7407         int index;
7408         int full = 0;
7409         int ret = 0;
7410
7411         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7412
7413         /* odd, couldn't find the block group, leave it alone */
7414         if (!block_group)
7415                 return -1;
7416
7417         min_free = btrfs_block_group_used(&block_group->item);
7418
7419         /* no bytes used, we're good */
7420         if (!min_free)
7421                 goto out;
7422
7423         space_info = block_group->space_info;
7424         spin_lock(&space_info->lock);
7425
7426         full = space_info->full;
7427
7428         /*
7429          * if this is the last block group we have in this space, we can't
7430          * relocate it unless we're able to allocate a new chunk below.
7431          *
7432          * Otherwise, we need to make sure we have room in the space to handle
7433          * all of the extents from this block group.  If we can, we're good
7434          */
7435         if ((space_info->total_bytes != block_group->key.offset) &&
7436             (space_info->bytes_used + space_info->bytes_reserved +
7437              space_info->bytes_pinned + space_info->bytes_readonly +
7438              min_free < space_info->total_bytes)) {
7439                 spin_unlock(&space_info->lock);
7440                 goto out;
7441         }
7442         spin_unlock(&space_info->lock);
7443
7444         /*
7445          * ok we don't have enough space, but maybe we have free space on our
7446          * devices to allocate new chunks for relocation, so loop through our
7447          * alloc devices and guess if we have enough space.  if this block
7448          * group is going to be restriped, run checks against the target
7449          * profile instead of the current one.
7450          */
7451         ret = -1;
7452
7453         /*
7454          * index:
7455          *      0: raid10
7456          *      1: raid1
7457          *      2: dup
7458          *      3: raid0
7459          *      4: single
7460          */
7461         target = get_restripe_target(root->fs_info, block_group->flags);
7462         if (target) {
7463                 index = __get_block_group_index(extended_to_chunk(target));
7464         } else {
7465                 /*
7466                  * this is just a balance, so if we were marked as full
7467                  * we know there is no space for a new chunk
7468                  */
7469                 if (full)
7470                         goto out;
7471
7472                 index = get_block_group_index(block_group);
7473         }
7474
7475         if (index == 0) {
7476                 dev_min = 4;
7477                 /* Divide by 2 */
7478                 min_free >>= 1;
7479         } else if (index == 1) {
7480                 dev_min = 2;
7481         } else if (index == 2) {
7482                 /* Multiply by 2 */
7483                 min_free <<= 1;
7484         } else if (index == 3) {
7485                 dev_min = fs_devices->rw_devices;
7486                 do_div(min_free, dev_min);
7487         }
7488
7489         mutex_lock(&root->fs_info->chunk_mutex);
7490         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7491                 u64 dev_offset;
7492
7493                 /*
7494                  * check to make sure we can actually find a chunk with enough
7495                  * space to fit our block group in.
7496                  */
7497                 if (device->total_bytes > device->bytes_used + min_free) {
7498                         ret = find_free_dev_extent(device, min_free,
7499                                                    &dev_offset, NULL);
7500                         if (!ret)
7501                                 dev_nr++;
7502
7503                         if (dev_nr >= dev_min)
7504                                 break;
7505
7506                         ret = -1;
7507                 }
7508         }
7509         mutex_unlock(&root->fs_info->chunk_mutex);
7510 out:
7511         btrfs_put_block_group(block_group);
7512         return ret;
7513 }
7514
7515 static int find_first_block_group(struct btrfs_root *root,
7516                 struct btrfs_path *path, struct btrfs_key *key)
7517 {
7518         int ret = 0;
7519         struct btrfs_key found_key;
7520         struct extent_buffer *leaf;
7521         int slot;
7522
7523         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7524         if (ret < 0)
7525                 goto out;
7526
7527         while (1) {
7528                 slot = path->slots[0];
7529                 leaf = path->nodes[0];
7530                 if (slot >= btrfs_header_nritems(leaf)) {
7531                         ret = btrfs_next_leaf(root, path);
7532                         if (ret == 0)
7533                                 continue;
7534                         if (ret < 0)
7535                                 goto out;
7536                         break;
7537                 }
7538                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7539
7540                 if (found_key.objectid >= key->objectid &&
7541                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7542                         ret = 0;
7543                         goto out;
7544                 }
7545                 path->slots[0]++;
7546         }
7547 out:
7548         return ret;
7549 }
7550
7551 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7552 {
7553         struct btrfs_block_group_cache *block_group;
7554         u64 last = 0;
7555
7556         while (1) {
7557                 struct inode *inode;
7558
7559                 block_group = btrfs_lookup_first_block_group(info, last);
7560                 while (block_group) {
7561                         spin_lock(&block_group->lock);
7562                         if (block_group->iref)
7563                                 break;
7564                         spin_unlock(&block_group->lock);
7565                         block_group = next_block_group(info->tree_root,
7566                                                        block_group);
7567                 }
7568                 if (!block_group) {
7569                         if (last == 0)
7570                                 break;
7571                         last = 0;
7572                         continue;
7573                 }
7574
7575                 inode = block_group->inode;
7576                 block_group->iref = 0;
7577                 block_group->inode = NULL;
7578                 spin_unlock(&block_group->lock);
7579                 iput(inode);
7580                 last = block_group->key.objectid + block_group->key.offset;
7581                 btrfs_put_block_group(block_group);
7582         }
7583 }
7584
7585 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7586 {
7587         struct btrfs_block_group_cache *block_group;
7588         struct btrfs_space_info *space_info;
7589         struct btrfs_caching_control *caching_ctl;
7590         struct rb_node *n;
7591
7592         down_write(&info->extent_commit_sem);
7593         while (!list_empty(&info->caching_block_groups)) {
7594                 caching_ctl = list_entry(info->caching_block_groups.next,
7595                                          struct btrfs_caching_control, list);
7596                 list_del(&caching_ctl->list);
7597                 put_caching_control(caching_ctl);
7598         }
7599         up_write(&info->extent_commit_sem);
7600
7601         spin_lock(&info->block_group_cache_lock);
7602         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7603                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7604                                        cache_node);
7605                 rb_erase(&block_group->cache_node,
7606                          &info->block_group_cache_tree);
7607                 spin_unlock(&info->block_group_cache_lock);
7608
7609                 down_write(&block_group->space_info->groups_sem);
7610                 list_del(&block_group->list);
7611                 up_write(&block_group->space_info->groups_sem);
7612
7613                 if (block_group->cached == BTRFS_CACHE_STARTED)
7614                         wait_block_group_cache_done(block_group);
7615
7616                 /*
7617                  * We haven't cached this block group, which means we could
7618                  * possibly have excluded extents on this block group.
7619                  */
7620                 if (block_group->cached == BTRFS_CACHE_NO)
7621                         free_excluded_extents(info->extent_root, block_group);
7622
7623                 btrfs_remove_free_space_cache(block_group);
7624                 btrfs_put_block_group(block_group);
7625
7626                 spin_lock(&info->block_group_cache_lock);
7627         }
7628         spin_unlock(&info->block_group_cache_lock);
7629
7630         /* now that all the block groups are freed, go through and
7631          * free all the space_info structs.  This is only called during
7632          * the final stages of unmount, and so we know nobody is
7633          * using them.  We call synchronize_rcu() once before we start,
7634          * just to be on the safe side.
7635          */
7636         synchronize_rcu();
7637
7638         release_global_block_rsv(info);
7639
7640         while(!list_empty(&info->space_info)) {
7641                 space_info = list_entry(info->space_info.next,
7642                                         struct btrfs_space_info,
7643                                         list);
7644                 if (space_info->bytes_pinned > 0 ||
7645                     space_info->bytes_reserved > 0 ||
7646                     space_info->bytes_may_use > 0) {
7647                         WARN_ON(1);
7648                         dump_space_info(space_info, 0, 0);
7649                 }
7650                 list_del(&space_info->list);
7651                 kfree(space_info);
7652         }
7653         return 0;
7654 }
7655
7656 static void __link_block_group(struct btrfs_space_info *space_info,
7657                                struct btrfs_block_group_cache *cache)
7658 {
7659         int index = get_block_group_index(cache);
7660
7661         down_write(&space_info->groups_sem);
7662         list_add_tail(&cache->list, &space_info->block_groups[index]);
7663         up_write(&space_info->groups_sem);
7664 }
7665
7666 int btrfs_read_block_groups(struct btrfs_root *root)
7667 {
7668         struct btrfs_path *path;
7669         int ret;
7670         struct btrfs_block_group_cache *cache;
7671         struct btrfs_fs_info *info = root->fs_info;
7672         struct btrfs_space_info *space_info;
7673         struct btrfs_key key;
7674         struct btrfs_key found_key;
7675         struct extent_buffer *leaf;
7676         int need_clear = 0;
7677         u64 cache_gen;
7678
7679         root = info->extent_root;
7680         key.objectid = 0;
7681         key.offset = 0;
7682         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7683         path = btrfs_alloc_path();
7684         if (!path)
7685                 return -ENOMEM;
7686         path->reada = 1;
7687
7688         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7689         if (btrfs_test_opt(root, SPACE_CACHE) &&
7690             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7691                 need_clear = 1;
7692         if (btrfs_test_opt(root, CLEAR_CACHE))
7693                 need_clear = 1;
7694
7695         while (1) {
7696                 ret = find_first_block_group(root, path, &key);
7697                 if (ret > 0)
7698                         break;
7699                 if (ret != 0)
7700                         goto error;
7701                 leaf = path->nodes[0];
7702                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7703                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7704                 if (!cache) {
7705                         ret = -ENOMEM;
7706                         goto error;
7707                 }
7708                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7709                                                 GFP_NOFS);
7710                 if (!cache->free_space_ctl) {
7711                         kfree(cache);
7712                         ret = -ENOMEM;
7713                         goto error;
7714                 }
7715
7716                 atomic_set(&cache->count, 1);
7717                 spin_lock_init(&cache->lock);
7718                 cache->fs_info = info;
7719                 INIT_LIST_HEAD(&cache->list);
7720                 INIT_LIST_HEAD(&cache->cluster_list);
7721
7722                 if (need_clear) {
7723                         /*
7724                          * When we mount with old space cache, we need to
7725                          * set BTRFS_DC_CLEAR and set dirty flag.
7726                          *
7727                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
7728                          *    truncate the old free space cache inode and
7729                          *    setup a new one.
7730                          * b) Setting 'dirty flag' makes sure that we flush
7731                          *    the new space cache info onto disk.
7732                          */
7733                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7734                         if (btrfs_test_opt(root, SPACE_CACHE))
7735                                 cache->dirty = 1;
7736                 }
7737
7738                 read_extent_buffer(leaf, &cache->item,
7739                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7740                                    sizeof(cache->item));
7741                 memcpy(&cache->key, &found_key, sizeof(found_key));
7742
7743                 key.objectid = found_key.objectid + found_key.offset;
7744                 btrfs_release_path(path);
7745                 cache->flags = btrfs_block_group_flags(&cache->item);
7746                 cache->sectorsize = root->sectorsize;
7747
7748                 btrfs_init_free_space_ctl(cache);
7749
7750                 /*
7751                  * We need to exclude the super stripes now so that the space
7752                  * info has super bytes accounted for, otherwise we'll think
7753                  * we have more space than we actually do.
7754                  */
7755                 exclude_super_stripes(root, cache);
7756
7757                 /*
7758                  * check for two cases, either we are full, and therefore
7759                  * don't need to bother with the caching work since we won't
7760                  * find any space, or we are empty, and we can just add all
7761                  * the space in and be done with it.  This saves us _alot_ of
7762                  * time, particularly in the full case.
7763                  */
7764                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7765                         cache->last_byte_to_unpin = (u64)-1;
7766                         cache->cached = BTRFS_CACHE_FINISHED;
7767                         free_excluded_extents(root, cache);
7768                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7769                         cache->last_byte_to_unpin = (u64)-1;
7770                         cache->cached = BTRFS_CACHE_FINISHED;
7771                         add_new_free_space(cache, root->fs_info,
7772                                            found_key.objectid,
7773                                            found_key.objectid +
7774                                            found_key.offset);
7775                         free_excluded_extents(root, cache);
7776                 }
7777
7778                 ret = update_space_info(info, cache->flags, found_key.offset,
7779                                         btrfs_block_group_used(&cache->item),
7780                                         &space_info);
7781                 BUG_ON(ret); /* -ENOMEM */
7782                 cache->space_info = space_info;
7783                 spin_lock(&cache->space_info->lock);
7784                 cache->space_info->bytes_readonly += cache->bytes_super;
7785                 spin_unlock(&cache->space_info->lock);
7786
7787                 __link_block_group(space_info, cache);
7788
7789                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7790                 BUG_ON(ret); /* Logic error */
7791
7792                 set_avail_alloc_bits(root->fs_info, cache->flags);
7793                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7794                         set_block_group_ro(cache, 1);
7795         }
7796
7797         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7798                 if (!(get_alloc_profile(root, space_info->flags) &
7799                       (BTRFS_BLOCK_GROUP_RAID10 |
7800                        BTRFS_BLOCK_GROUP_RAID1 |
7801                        BTRFS_BLOCK_GROUP_DUP)))
7802                         continue;
7803                 /*
7804                  * avoid allocating from un-mirrored block group if there are
7805                  * mirrored block groups.
7806                  */
7807                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7808                         set_block_group_ro(cache, 1);
7809                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7810                         set_block_group_ro(cache, 1);
7811         }
7812
7813         init_global_block_rsv(info);
7814         ret = 0;
7815 error:
7816         btrfs_free_path(path);
7817         return ret;
7818 }
7819
7820 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7821                            struct btrfs_root *root, u64 bytes_used,
7822                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7823                            u64 size)
7824 {
7825         int ret;
7826         struct btrfs_root *extent_root;
7827         struct btrfs_block_group_cache *cache;
7828
7829         extent_root = root->fs_info->extent_root;
7830
7831         root->fs_info->last_trans_log_full_commit = trans->transid;
7832
7833         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7834         if (!cache)
7835                 return -ENOMEM;
7836         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7837                                         GFP_NOFS);
7838         if (!cache->free_space_ctl) {
7839                 kfree(cache);
7840                 return -ENOMEM;
7841         }
7842
7843         cache->key.objectid = chunk_offset;
7844         cache->key.offset = size;
7845         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7846         cache->sectorsize = root->sectorsize;
7847         cache->fs_info = root->fs_info;
7848
7849         atomic_set(&cache->count, 1);
7850         spin_lock_init(&cache->lock);
7851         INIT_LIST_HEAD(&cache->list);
7852         INIT_LIST_HEAD(&cache->cluster_list);
7853
7854         btrfs_init_free_space_ctl(cache);
7855
7856         btrfs_set_block_group_used(&cache->item, bytes_used);
7857         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7858         cache->flags = type;
7859         btrfs_set_block_group_flags(&cache->item, type);
7860
7861         cache->last_byte_to_unpin = (u64)-1;
7862         cache->cached = BTRFS_CACHE_FINISHED;
7863         exclude_super_stripes(root, cache);
7864
7865         add_new_free_space(cache, root->fs_info, chunk_offset,
7866                            chunk_offset + size);
7867
7868         free_excluded_extents(root, cache);
7869
7870         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7871                                 &cache->space_info);
7872         BUG_ON(ret); /* -ENOMEM */
7873         update_global_block_rsv(root->fs_info);
7874
7875         spin_lock(&cache->space_info->lock);
7876         cache->space_info->bytes_readonly += cache->bytes_super;
7877         spin_unlock(&cache->space_info->lock);
7878
7879         __link_block_group(cache->space_info, cache);
7880
7881         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7882         BUG_ON(ret); /* Logic error */
7883
7884         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7885                                 sizeof(cache->item));
7886         if (ret) {
7887                 btrfs_abort_transaction(trans, extent_root, ret);
7888                 return ret;
7889         }
7890
7891         set_avail_alloc_bits(extent_root->fs_info, type);
7892
7893         return 0;
7894 }
7895
7896 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7897 {
7898         u64 extra_flags = chunk_to_extended(flags) &
7899                                 BTRFS_EXTENDED_PROFILE_MASK;
7900
7901         if (flags & BTRFS_BLOCK_GROUP_DATA)
7902                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7903         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7904                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7905         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7906                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7907 }
7908
7909 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7910                              struct btrfs_root *root, u64 group_start)
7911 {
7912         struct btrfs_path *path;
7913         struct btrfs_block_group_cache *block_group;
7914         struct btrfs_free_cluster *cluster;
7915         struct btrfs_root *tree_root = root->fs_info->tree_root;
7916         struct btrfs_key key;
7917         struct inode *inode;
7918         int ret;
7919         int index;
7920         int factor;
7921
7922         root = root->fs_info->extent_root;
7923
7924         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7925         BUG_ON(!block_group);
7926         BUG_ON(!block_group->ro);
7927
7928         /*
7929          * Free the reserved super bytes from this block group before
7930          * remove it.
7931          */
7932         free_excluded_extents(root, block_group);
7933
7934         memcpy(&key, &block_group->key, sizeof(key));
7935         index = get_block_group_index(block_group);
7936         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7937                                   BTRFS_BLOCK_GROUP_RAID1 |
7938                                   BTRFS_BLOCK_GROUP_RAID10))
7939                 factor = 2;
7940         else
7941                 factor = 1;
7942
7943         /* make sure this block group isn't part of an allocation cluster */
7944         cluster = &root->fs_info->data_alloc_cluster;
7945         spin_lock(&cluster->refill_lock);
7946         btrfs_return_cluster_to_free_space(block_group, cluster);
7947         spin_unlock(&cluster->refill_lock);
7948
7949         /*
7950          * make sure this block group isn't part of a metadata
7951          * allocation cluster
7952          */
7953         cluster = &root->fs_info->meta_alloc_cluster;
7954         spin_lock(&cluster->refill_lock);
7955         btrfs_return_cluster_to_free_space(block_group, cluster);
7956         spin_unlock(&cluster->refill_lock);
7957
7958         path = btrfs_alloc_path();
7959         if (!path) {
7960                 ret = -ENOMEM;
7961                 goto out;
7962         }
7963
7964         inode = lookup_free_space_inode(tree_root, block_group, path);
7965         if (!IS_ERR(inode)) {
7966                 ret = btrfs_orphan_add(trans, inode);
7967                 if (ret) {
7968                         btrfs_add_delayed_iput(inode);
7969                         goto out;
7970                 }
7971                 clear_nlink(inode);
7972                 /* One for the block groups ref */
7973                 spin_lock(&block_group->lock);
7974                 if (block_group->iref) {
7975                         block_group->iref = 0;
7976                         block_group->inode = NULL;
7977                         spin_unlock(&block_group->lock);
7978                         iput(inode);
7979                 } else {
7980                         spin_unlock(&block_group->lock);
7981                 }
7982                 /* One for our lookup ref */
7983                 btrfs_add_delayed_iput(inode);
7984         }
7985
7986         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7987         key.offset = block_group->key.objectid;
7988         key.type = 0;
7989
7990         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7991         if (ret < 0)
7992                 goto out;
7993         if (ret > 0)
7994                 btrfs_release_path(path);
7995         if (ret == 0) {
7996                 ret = btrfs_del_item(trans, tree_root, path);
7997                 if (ret)
7998                         goto out;
7999                 btrfs_release_path(path);
8000         }
8001
8002         spin_lock(&root->fs_info->block_group_cache_lock);
8003         rb_erase(&block_group->cache_node,
8004                  &root->fs_info->block_group_cache_tree);
8005         spin_unlock(&root->fs_info->block_group_cache_lock);
8006
8007         down_write(&block_group->space_info->groups_sem);
8008         /*
8009          * we must use list_del_init so people can check to see if they
8010          * are still on the list after taking the semaphore
8011          */
8012         list_del_init(&block_group->list);
8013         if (list_empty(&block_group->space_info->block_groups[index]))
8014                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8015         up_write(&block_group->space_info->groups_sem);
8016
8017         if (block_group->cached == BTRFS_CACHE_STARTED)
8018                 wait_block_group_cache_done(block_group);
8019
8020         btrfs_remove_free_space_cache(block_group);
8021
8022         spin_lock(&block_group->space_info->lock);
8023         block_group->space_info->total_bytes -= block_group->key.offset;
8024         block_group->space_info->bytes_readonly -= block_group->key.offset;
8025         block_group->space_info->disk_total -= block_group->key.offset * factor;
8026         spin_unlock(&block_group->space_info->lock);
8027
8028         memcpy(&key, &block_group->key, sizeof(key));
8029
8030         btrfs_clear_space_info_full(root->fs_info);
8031
8032         btrfs_put_block_group(block_group);
8033         btrfs_put_block_group(block_group);
8034
8035         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8036         if (ret > 0)
8037                 ret = -EIO;
8038         if (ret < 0)
8039                 goto out;
8040
8041         ret = btrfs_del_item(trans, root, path);
8042 out:
8043         btrfs_free_path(path);
8044         return ret;
8045 }
8046
8047 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8048 {
8049         struct btrfs_space_info *space_info;
8050         struct btrfs_super_block *disk_super;
8051         u64 features;
8052         u64 flags;
8053         int mixed = 0;
8054         int ret;
8055
8056         disk_super = fs_info->super_copy;
8057         if (!btrfs_super_root(disk_super))
8058                 return 1;
8059
8060         features = btrfs_super_incompat_flags(disk_super);
8061         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8062                 mixed = 1;
8063
8064         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8065         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8066         if (ret)
8067                 goto out;
8068
8069         if (mixed) {
8070                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8071                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8072         } else {
8073                 flags = BTRFS_BLOCK_GROUP_METADATA;
8074                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8075                 if (ret)
8076                         goto out;
8077
8078                 flags = BTRFS_BLOCK_GROUP_DATA;
8079                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8080         }
8081 out:
8082         return ret;
8083 }
8084
8085 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8086 {
8087         return unpin_extent_range(root, start, end);
8088 }
8089
8090 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8091                                u64 num_bytes, u64 *actual_bytes)
8092 {
8093         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8094 }
8095
8096 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8097 {
8098         struct btrfs_fs_info *fs_info = root->fs_info;
8099         struct btrfs_block_group_cache *cache = NULL;
8100         u64 group_trimmed;
8101         u64 start;
8102         u64 end;
8103         u64 trimmed = 0;
8104         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8105         int ret = 0;
8106
8107         /*
8108          * try to trim all FS space, our block group may start from non-zero.
8109          */
8110         if (range->len == total_bytes)
8111                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8112         else
8113                 cache = btrfs_lookup_block_group(fs_info, range->start);
8114
8115         while (cache) {
8116                 if (cache->key.objectid >= (range->start + range->len)) {
8117                         btrfs_put_block_group(cache);
8118                         break;
8119                 }
8120
8121                 start = max(range->start, cache->key.objectid);
8122                 end = min(range->start + range->len,
8123                                 cache->key.objectid + cache->key.offset);
8124
8125                 if (end - start >= range->minlen) {
8126                         if (!block_group_cache_done(cache)) {
8127                                 ret = cache_block_group(cache, NULL, root, 0);
8128                                 if (!ret)
8129                                         wait_block_group_cache_done(cache);
8130                         }
8131                         ret = btrfs_trim_block_group(cache,
8132                                                      &group_trimmed,
8133                                                      start,
8134                                                      end,
8135                                                      range->minlen);
8136
8137                         trimmed += group_trimmed;
8138                         if (ret) {
8139                                 btrfs_put_block_group(cache);
8140                                 break;
8141                         }
8142                 }
8143
8144                 cache = next_block_group(fs_info->tree_root, cache);
8145         }
8146
8147         range->len = trimmed;
8148         return ret;
8149 }