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 /*
  38  * control flags for do_chunk_alloc's force field
  39  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  40  * if we really need one.
  41  *
  42  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  43  * if we have very few chunks already allocated.  This is
  44  * used as part of the clustering code to help make sure
  45  * we have a good pool of storage to cluster in, without
  46  * filling the FS with empty chunks
  47  *
  48  * CHUNK_ALLOC_FORCE means it must try to allocate one
  49  *
  50  */
  51 enum {
  52         CHUNK_ALLOC_NO_FORCE = 0,
  53         CHUNK_ALLOC_LIMITED = 1,
  54         CHUNK_ALLOC_FORCE = 2,
  55 };
  56
  57 /*
  58  * Control how reservations are dealt with.
  59  *
  60  * RESERVE_FREE - freeing a reservation.
  61  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  62  *   ENOSPC accounting
  63  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  64  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  65  */
  66 enum {
  67         RESERVE_FREE = 0,
  68         RESERVE_ALLOC = 1,
  69         RESERVE_ALLOC_NO_ACCOUNT = 2,
  70 };
  71
  72 static int update_block_group(struct btrfs_trans_handle *trans,
  73                               struct btrfs_root *root,
  74                               u64 bytenr, u64 num_bytes, int alloc);
  75 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  76                                 struct btrfs_root *root,
  77                                 u64 bytenr, u64 num_bytes, u64 parent,
  78                                 u64 root_objectid, u64 owner_objectid,
  79                                 u64 owner_offset, int refs_to_drop,
  80                                 struct btrfs_delayed_extent_op *extra_op);
  81 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  82                                     struct extent_buffer *leaf,
  83                                     struct btrfs_extent_item *ei);
  84 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  85                                       struct btrfs_root *root,
  86                                       u64 parent, u64 root_objectid,
  87                                       u64 flags, u64 owner, u64 offset,
  88                                       struct btrfs_key *ins, int ref_mod);
  89 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  90                                      struct btrfs_root *root,
  91                                      u64 parent, u64 root_objectid,
  92                                      u64 flags, struct btrfs_disk_key *key,
  93                                      int level, struct btrfs_key *ins);
  94 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  95                           struct btrfs_root *extent_root, u64 alloc_bytes,
  96                           u64 flags, int force);
  97 static int find_next_key(struct btrfs_path *path, int level,
  98                          struct btrfs_key *key);
  99 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 100                             int dump_block_groups);
 101 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 102                                        u64 num_bytes, int reserve);
 103
 104 static noinline int
 105 block_group_cache_done(struct btrfs_block_group_cache *cache)
 106 {
 107         smp_mb();
 108         return cache->cached == BTRFS_CACHE_FINISHED;
 109 }
 110
 111 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 112 {
 113         return (cache->flags & bits) == bits;
 114 }
 115
 116 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 117 {
 118         atomic_inc(&cache->count);
 119 }
 120
 121 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 122 {
 123         if (atomic_dec_and_test(&cache->count)) {
 124                 WARN_ON(cache->pinned > 0);
 125                 WARN_ON(cache->reserved > 0);
 126                 kfree(cache->free_space_ctl);
 127                 kfree(cache);
 128         }
 129 }
 130
 131 /*
 132  * this adds the block group to the fs_info rb tree for the block group
 133  * cache
 134  */
 135 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 136                                 struct btrfs_block_group_cache *block_group)
 137 {
 138         struct rb_node **p;
 139         struct rb_node *parent = NULL;
 140         struct btrfs_block_group_cache *cache;
 141
 142         spin_lock(&info->block_group_cache_lock);
 143         p = &info->block_group_cache_tree.rb_node;
 144
 145         while (*p) {
 146                 parent = *p;
 147                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 148                                  cache_node);
 149                 if (block_group->key.objectid < cache->key.objectid) {
 150                         p = &(*p)->rb_left;
 151                 } else if (block_group->key.objectid > cache->key.objectid) {
 152                         p = &(*p)->rb_right;
 153                 } else {
 154                         spin_unlock(&info->block_group_cache_lock);
 155                         return -EEXIST;
 156                 }
 157         }
 158
 159         rb_link_node(&block_group->cache_node, parent, p);
 160         rb_insert_color(&block_group->cache_node,
 161                         &info->block_group_cache_tree);
 162         spin_unlock(&info->block_group_cache_lock);
 163
 164         return 0;
 165 }
 166
 167 /*
 168  * This will return the block group at or after bytenr if contains is 0, else
 169  * it will return the block group that contains the bytenr
 170  */
 171 static struct btrfs_block_group_cache *
 172 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 173                               int contains)
 174 {
 175         struct btrfs_block_group_cache *cache, *ret = NULL;
 176         struct rb_node *n;
 177         u64 end, start;
 178
 179         spin_lock(&info->block_group_cache_lock);
 180         n = info->block_group_cache_tree.rb_node;
 181
 182         while (n) {
 183                 cache = rb_entry(n, struct btrfs_block_group_cache,
 184                                  cache_node);
 185                 end = cache->key.objectid + cache->key.offset - 1;
 186                 start = cache->key.objectid;
 187
 188                 if (bytenr < start) {
 189                         if (!contains && (!ret || start < ret->key.objectid))
 190                                 ret = cache;
 191                         n = n->rb_left;
 192                 } else if (bytenr > start) {
 193                         if (contains && bytenr <= end) {
 194                                 ret = cache;
 195                                 break;
 196                         }
 197                         n = n->rb_right;
 198                 } else {
 199                         ret = cache;
 200                         break;
 201                 }
 202         }
 203         if (ret)
 204                 btrfs_get_block_group(ret);
 205         spin_unlock(&info->block_group_cache_lock);
 206
 207         return ret;
 208 }
 209
 210 static int add_excluded_extent(struct btrfs_root *root,
 211                                u64 start, u64 num_bytes)
 212 {
 213         u64 end = start + num_bytes - 1;
 214         set_extent_bits(&root->fs_info->freed_extents[0],
 215                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 216         set_extent_bits(&root->fs_info->freed_extents[1],
 217                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 218         return 0;
 219 }
 220
 221 static void free_excluded_extents(struct btrfs_root *root,
 222                                   struct btrfs_block_group_cache *cache)
 223 {
 224         u64 start, end;
 225
 226         start = cache->key.objectid;
 227         end = start + cache->key.offset - 1;
 228
 229         clear_extent_bits(&root->fs_info->freed_extents[0],
 230                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 231         clear_extent_bits(&root->fs_info->freed_extents[1],
 232                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 233 }
 234
 235 static int exclude_super_stripes(struct btrfs_root *root,
 236                                  struct btrfs_block_group_cache *cache)
 237 {
 238         u64 bytenr;
 239         u64 *logical;
 240         int stripe_len;
 241         int i, nr, ret;
 242
 243         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 244                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 245                 cache->bytes_super += stripe_len;
 246                 ret = add_excluded_extent(root, cache->key.objectid,
 247                                           stripe_len);
 248                 BUG_ON(ret); /* -ENOMEM */
 249         }
 250
 251         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 252                 bytenr = btrfs_sb_offset(i);
 253                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 254                                        cache->key.objectid, bytenr,
 255                                        0, &logical, &nr, &stripe_len);
 256                 BUG_ON(ret); /* -ENOMEM */
 257
 258                 while (nr--) {
 259                         cache->bytes_super += stripe_len;
 260                         ret = add_excluded_extent(root, logical[nr],
 261                                                   stripe_len);
 262                         BUG_ON(ret); /* -ENOMEM */
 263                 }
 264
 265                 kfree(logical);
 266         }
 267         return 0;
 268 }
 269
 270 static struct btrfs_caching_control *
 271 get_caching_control(struct btrfs_block_group_cache *cache)
 272 {
 273         struct btrfs_caching_control *ctl;
 274
 275         spin_lock(&cache->lock);
 276         if (cache->cached != BTRFS_CACHE_STARTED) {
 277                 spin_unlock(&cache->lock);
 278                 return NULL;
 279         }
 280
 281         /* We're loading it the fast way, so we don't have a caching_ctl. */
 282         if (!cache->caching_ctl) {
 283                 spin_unlock(&cache->lock);
 284                 return NULL;
 285         }
 286
 287         ctl = cache->caching_ctl;
 288         atomic_inc(&ctl->count);
 289         spin_unlock(&cache->lock);
 290         return ctl;
 291 }
 292
 293 static void put_caching_control(struct btrfs_caching_control *ctl)
 294 {
 295         if (atomic_dec_and_test(&ctl->count))
 296                 kfree(ctl);
 297 }
 298
 299 /*
 300  * this is only called by cache_block_group, since we could have freed extents
 301  * we need to check the pinned_extents for any extents that can't be used yet
 302  * since their free space will be released as soon as the transaction commits.
 303  */
 304 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 305                               struct btrfs_fs_info *info, u64 start, u64 end)
 306 {
 307         u64 extent_start, extent_end, size, total_added = 0;
 308         int ret;
 309
 310         while (start < end) {
 311                 ret = find_first_extent_bit(info->pinned_extents, start,
 312                                             &extent_start, &extent_end,
 313                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 314                 if (ret)
 315                         break;
 316
 317                 if (extent_start <= start) {
 318                         start = extent_end + 1;
 319                 } else if (extent_start > start && extent_start < end) {
 320                         size = extent_start - start;
 321                         total_added += size;
 322                         ret = btrfs_add_free_space(block_group, start,
 323                                                    size);
 324                         BUG_ON(ret); /* -ENOMEM or logic error */
 325                         start = extent_end + 1;
 326                 } else {
 327                         break;
 328                 }
 329         }
 330
 331         if (start < end) {
 332                 size = end - start;
 333                 total_added += size;
 334                 ret = btrfs_add_free_space(block_group, start, size);
 335                 BUG_ON(ret); /* -ENOMEM or logic error */
 336         }
 337
 338         return total_added;
 339 }
 340
 341 static noinline void caching_thread(struct btrfs_work *work)
 342 {
 343         struct btrfs_block_group_cache *block_group;
 344         struct btrfs_fs_info *fs_info;
 345         struct btrfs_caching_control *caching_ctl;
 346         struct btrfs_root *extent_root;
 347         struct btrfs_path *path;
 348         struct extent_buffer *leaf;
 349         struct btrfs_key key;
 350         u64 total_found = 0;
 351         u64 last = 0;
 352         u32 nritems;
 353         int ret = 0;
 354
 355         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 356         block_group = caching_ctl->block_group;
 357         fs_info = block_group->fs_info;
 358         extent_root = fs_info->extent_root;
 359
 360         path = btrfs_alloc_path();
 361         if (!path)
 362                 goto out;
 363
 364         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 365
 366         /*
 367          * We don't want to deadlock with somebody trying to allocate a new
 368          * extent for the extent root while also trying to search the extent
 369          * root to add free space.  So we skip locking and search the commit
 370          * root, since its read-only
 371          */
 372         path->skip_locking = 1;
 373         path->search_commit_root = 1;
 374         path->reada = 1;
 375
 376         key.objectid = last;
 377         key.offset = 0;
 378         key.type = BTRFS_EXTENT_ITEM_KEY;
 379 again:
 380         mutex_lock(&caching_ctl->mutex);
 381         /* need to make sure the commit_root doesn't disappear */
 382         down_read(&fs_info->extent_commit_sem);
 383
 384         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 385         if (ret < 0)
 386                 goto err;
 387
 388         leaf = path->nodes[0];
 389         nritems = btrfs_header_nritems(leaf);
 390
 391         while (1) {
 392                 if (btrfs_fs_closing(fs_info) > 1) {
 393                         last = (u64)-1;
 394                         break;
 395                 }
 396
 397                 if (path->slots[0] < nritems) {
 398                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 399                 } else {
 400                         ret = find_next_key(path, 0, &key);
 401                         if (ret)
 402                                 break;
 403
 404                         if (need_resched() ||
 405                             btrfs_next_leaf(extent_root, path)) {
 406                                 caching_ctl->progress = last;
 407                                 btrfs_release_path(path);
 408                                 up_read(&fs_info->extent_commit_sem);
 409                                 mutex_unlock(&caching_ctl->mutex);
 410                                 cond_resched();
 411                                 goto again;
 412                         }
 413                         leaf = path->nodes[0];
 414                         nritems = btrfs_header_nritems(leaf);
 415                         continue;
 416                 }
 417
 418                 if (key.objectid < block_group->key.objectid) {
 419                         path->slots[0]++;
 420                         continue;
 421                 }
 422
 423                 if (key.objectid >= block_group->key.objectid +
 424                     block_group->key.offset)
 425                         break;
 426
 427                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 428                         total_found += add_new_free_space(block_group,
 429                                                           fs_info, last,
 430                                                           key.objectid);
 431                         last = key.objectid + key.offset;
 432
 433                         if (total_found > (1024 * 1024 * 2)) {
 434                                 total_found = 0;
 435                                 wake_up(&caching_ctl->wait);
 436                         }
 437                 }
 438                 path->slots[0]++;
 439         }
 440         ret = 0;
 441
 442         total_found += add_new_free_space(block_group, fs_info, last,
 443                                           block_group->key.objectid +
 444                                           block_group->key.offset);
 445         caching_ctl->progress = (u64)-1;
 446
 447         spin_lock(&block_group->lock);
 448         block_group->caching_ctl = NULL;
 449         block_group->cached = BTRFS_CACHE_FINISHED;
 450         spin_unlock(&block_group->lock);
 451
 452 err:
 453         btrfs_free_path(path);
 454         up_read(&fs_info->extent_commit_sem);
 455
 456         free_excluded_extents(extent_root, block_group);
 457
 458         mutex_unlock(&caching_ctl->mutex);
 459 out:
 460         wake_up(&caching_ctl->wait);
 461
 462         put_caching_control(caching_ctl);
 463         btrfs_put_block_group(block_group);
 464 }
 465
 466 static int cache_block_group(struct btrfs_block_group_cache *cache,
 467                              struct btrfs_trans_handle *trans,
 468                              struct btrfs_root *root,
 469                              int load_cache_only)
 470 {
 471         DEFINE_WAIT(wait);
 472         struct btrfs_fs_info *fs_info = cache->fs_info;
 473         struct btrfs_caching_control *caching_ctl;
 474         int ret = 0;
 475
 476         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 477         if (!caching_ctl)
 478                 return -ENOMEM;
 479
 480         INIT_LIST_HEAD(&caching_ctl->list);
 481         mutex_init(&caching_ctl->mutex);
 482         init_waitqueue_head(&caching_ctl->wait);
 483         caching_ctl->block_group = cache;
 484         caching_ctl->progress = cache->key.objectid;
 485         atomic_set(&caching_ctl->count, 1);
 486         caching_ctl->work.func = caching_thread;
 487
 488         spin_lock(&cache->lock);
 489         /*
 490          * This should be a rare occasion, but this could happen I think in the
 491          * case where one thread starts to load the space cache info, and then
 492          * some other thread starts a transaction commit which tries to do an
 493          * allocation while the other thread is still loading the space cache
 494          * info.  The previous loop should have kept us from choosing this block
 495          * group, but if we've moved to the state where we will wait on caching
 496          * block groups we need to first check if we're doing a fast load here,
 497          * so we can wait for it to finish, otherwise we could end up allocating
 498          * from a block group who's cache gets evicted for one reason or
 499          * another.
 500          */
 501         while (cache->cached == BTRFS_CACHE_FAST) {
 502                 struct btrfs_caching_control *ctl;
 503
 504                 ctl = cache->caching_ctl;
 505                 atomic_inc(&ctl->count);
 506                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 507                 spin_unlock(&cache->lock);
 508
 509                 schedule();
 510
 511                 finish_wait(&ctl->wait, &wait);
 512                 put_caching_control(ctl);
 513                 spin_lock(&cache->lock);
 514         }
 515
 516         if (cache->cached != BTRFS_CACHE_NO) {
 517                 spin_unlock(&cache->lock);
 518                 kfree(caching_ctl);
 519                 return 0;
 520         }
 521         WARN_ON(cache->caching_ctl);
 522         cache->caching_ctl = caching_ctl;
 523         cache->cached = BTRFS_CACHE_FAST;
 524         spin_unlock(&cache->lock);
 525
 526         /*
 527          * We can't do the read from on-disk cache during a commit since we need
 528          * to have the normal tree locking.  Also if we are currently trying to
 529          * allocate blocks for the tree root we can't do the fast caching since
 530          * we likely hold important locks.
 531          */
 532         if (trans && (!trans->transaction->in_commit) &&
 533             (root && root != root->fs_info->tree_root) &&
 534             btrfs_test_opt(root, 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         int ret;
2223         int count = 0;
2224         int must_insert_reserved = 0;
2225
2226         delayed_refs = &trans->transaction->delayed_refs;
2227         while (1) {
2228                 if (!locked_ref) {
2229                         /* pick a new head ref from the cluster list */
2230                         if (list_empty(cluster))
2231                                 break;
2232
2233                         locked_ref = list_entry(cluster->next,
2234                                      struct btrfs_delayed_ref_head, cluster);
2235
2236                         /* grab the lock that says we are going to process
2237                          * all the refs for this head */
2238                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2239
2240                         /*
2241                          * we may have dropped the spin lock to get the head
2242                          * mutex lock, and that might have given someone else
2243                          * time to free the head.  If that's true, it has been
2244                          * removed from our list and we can move on.
2245                          */
2246                         if (ret == -EAGAIN) {
2247                                 locked_ref = NULL;
2248                                 count++;
2249                                 continue;
2250                         }
2251                 }
2252
2253                 /*
2254                  * locked_ref is the head node, so we have to go one
2255                  * node back for any delayed ref updates
2256                  */
2257                 ref = select_delayed_ref(locked_ref);
2258
2259                 if (ref && ref->seq &&
2260                     btrfs_check_delayed_seq(delayed_refs, ref->seq)) {
2261                         /*
2262                          * there are still refs with lower seq numbers in the
2263                          * process of being added. Don't run this ref yet.
2264                          */
2265                         list_del_init(&locked_ref->cluster);
2266                         mutex_unlock(&locked_ref->mutex);
2267                         locked_ref = NULL;
2268                         delayed_refs->num_heads_ready++;
2269                         spin_unlock(&delayed_refs->lock);
2270                         cond_resched();
2271                         spin_lock(&delayed_refs->lock);
2272                         continue;
2273                 }
2274
2275                 /*
2276                  * record the must insert reserved flag before we
2277                  * drop the spin lock.
2278                  */
2279                 must_insert_reserved = locked_ref->must_insert_reserved;
2280                 locked_ref->must_insert_reserved = 0;
2281
2282                 extent_op = locked_ref->extent_op;
2283                 locked_ref->extent_op = NULL;
2284
2285                 if (!ref) {
2286                         /* All delayed refs have been processed, Go ahead
2287                          * and send the head node to run_one_delayed_ref,
2288                          * so that any accounting fixes can happen
2289                          */
2290                         ref = &locked_ref->node;
2291
2292                         if (extent_op && must_insert_reserved) {
2293                                 kfree(extent_op);
2294                                 extent_op = NULL;
2295                         }
2296
2297                         if (extent_op) {
2298                                 spin_unlock(&delayed_refs->lock);
2299
2300                                 ret = run_delayed_extent_op(trans, root,
2301                                                             ref, extent_op);
2302                                 kfree(extent_op);
2303
2304                                 if (ret) {
2305                                         printk(KERN_DEBUG "btrfs: run_delayed_extent_op returned %d\n", ret);
2306                                         return ret;
2307                                 }
2308
2309                                 goto next;
2310                         }
2311
2312                         list_del_init(&locked_ref->cluster);
2313                         locked_ref = NULL;
2314                 }
2315
2316                 ref->in_tree = 0;
2317                 rb_erase(&ref->rb_node, &delayed_refs->root);
2318                 delayed_refs->num_entries--;
2319                 /*
2320                  * we modified num_entries, but as we're currently running
2321                  * delayed refs, skip
2322                  *     wake_up(&delayed_refs->seq_wait);
2323                  * here.
2324                  */
2325                 spin_unlock(&delayed_refs->lock);
2326
2327                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2328                                           must_insert_reserved);
2329
2330                 btrfs_put_delayed_ref(ref);
2331                 kfree(extent_op);
2332                 count++;
2333
2334                 if (ret) {
2335                         printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
2336                         return ret;
2337                 }
2338
2339 next:
2340                 do_chunk_alloc(trans, root->fs_info->extent_root,
2341                                2 * 1024 * 1024,
2342                                btrfs_get_alloc_profile(root, 0),
2343                                CHUNK_ALLOC_NO_FORCE);
2344                 cond_resched();
2345                 spin_lock(&delayed_refs->lock);
2346         }
2347         return count;
2348 }
2349
2350
2351 static void wait_for_more_refs(struct btrfs_delayed_ref_root *delayed_refs,
2352                         unsigned long num_refs)
2353 {
2354         struct list_head *first_seq = delayed_refs->seq_head.next;
2355
2356         spin_unlock(&delayed_refs->lock);
2357         pr_debug("waiting for more refs (num %ld, first %p)\n",
2358                  num_refs, first_seq);
2359         wait_event(delayed_refs->seq_wait,
2360                    num_refs != delayed_refs->num_entries ||
2361                    delayed_refs->seq_head.next != first_seq);
2362         pr_debug("done waiting for more refs (num %ld, first %p)\n",
2363                  delayed_refs->num_entries, delayed_refs->seq_head.next);
2364         spin_lock(&delayed_refs->lock);
2365 }
2366
2367 /*
2368  * this starts processing the delayed reference count updates and
2369  * extent insertions we have queued up so far.  count can be
2370  * 0, which means to process everything in the tree at the start
2371  * of the run (but not newly added entries), or it can be some target
2372  * number you'd like to process.
2373  *
2374  * Returns 0 on success or if called with an aborted transaction
2375  * Returns <0 on error and aborts the transaction
2376  */
2377 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2378                            struct btrfs_root *root, unsigned long count)
2379 {
2380         struct rb_node *node;
2381         struct btrfs_delayed_ref_root *delayed_refs;
2382         struct btrfs_delayed_ref_node *ref;
2383         struct list_head cluster;
2384         int ret;
2385         u64 delayed_start;
2386         int run_all = count == (unsigned long)-1;
2387         int run_most = 0;
2388         unsigned long num_refs = 0;
2389         int consider_waiting;
2390
2391         /* We'll clean this up in btrfs_cleanup_transaction */
2392         if (trans->aborted)
2393                 return 0;
2394
2395         if (root == root->fs_info->extent_root)
2396                 root = root->fs_info->tree_root;
2397
2398         do_chunk_alloc(trans, root->fs_info->extent_root,
2399                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2400                        CHUNK_ALLOC_NO_FORCE);
2401
2402         delayed_refs = &trans->transaction->delayed_refs;
2403         INIT_LIST_HEAD(&cluster);
2404 again:
2405         consider_waiting = 0;
2406         spin_lock(&delayed_refs->lock);
2407         if (count == 0) {
2408                 count = delayed_refs->num_entries * 2;
2409                 run_most = 1;
2410         }
2411         while (1) {
2412                 if (!(run_all || run_most) &&
2413                     delayed_refs->num_heads_ready < 64)
2414                         break;
2415
2416                 /*
2417                  * go find something we can process in the rbtree.  We start at
2418                  * the beginning of the tree, and then build a cluster
2419                  * of refs to process starting at the first one we are able to
2420                  * lock
2421                  */
2422                 delayed_start = delayed_refs->run_delayed_start;
2423                 ret = btrfs_find_ref_cluster(trans, &cluster,
2424                                              delayed_refs->run_delayed_start);
2425                 if (ret)
2426                         break;
2427
2428                 if (delayed_start >= delayed_refs->run_delayed_start) {
2429                         if (consider_waiting == 0) {
2430                                 /*
2431                                  * btrfs_find_ref_cluster looped. let's do one
2432                                  * more cycle. if we don't run any delayed ref
2433                                  * during that cycle (because we can't because
2434                                  * all of them are blocked) and if the number of
2435                                  * refs doesn't change, we avoid busy waiting.
2436                                  */
2437                                 consider_waiting = 1;
2438                                 num_refs = delayed_refs->num_entries;
2439                         } else {
2440                                 wait_for_more_refs(delayed_refs, num_refs);
2441                                 /*
2442                                  * after waiting, things have changed. we
2443                                  * dropped the lock and someone else might have
2444                                  * run some refs, built new clusters and so on.
2445                                  * therefore, we restart staleness detection.
2446                                  */
2447                                 consider_waiting = 0;
2448                         }
2449                 }
2450
2451                 ret = run_clustered_refs(trans, root, &cluster);
2452                 if (ret < 0) {
2453                         spin_unlock(&delayed_refs->lock);
2454                         btrfs_abort_transaction(trans, root, ret);
2455                         return ret;
2456                 }
2457
2458                 count -= min_t(unsigned long, ret, count);
2459
2460                 if (count == 0)
2461                         break;
2462
2463                 if (ret || delayed_refs->run_delayed_start == 0) {
2464                         /* refs were run, let's reset staleness detection */
2465                         consider_waiting = 0;
2466                 }
2467         }
2468
2469         if (run_all) {
2470                 node = rb_first(&delayed_refs->root);
2471                 if (!node)
2472                         goto out;
2473                 count = (unsigned long)-1;
2474
2475                 while (node) {
2476                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2477                                        rb_node);
2478                         if (btrfs_delayed_ref_is_head(ref)) {
2479                                 struct btrfs_delayed_ref_head *head;
2480
2481                                 head = btrfs_delayed_node_to_head(ref);
2482                                 atomic_inc(&ref->refs);
2483
2484                                 spin_unlock(&delayed_refs->lock);
2485                                 /*
2486                                  * Mutex was contended, block until it's
2487                                  * released and try again
2488                                  */
2489                                 mutex_lock(&head->mutex);
2490                                 mutex_unlock(&head->mutex);
2491
2492                                 btrfs_put_delayed_ref(ref);
2493                                 cond_resched();
2494                                 goto again;
2495                         }
2496                         node = rb_next(node);
2497                 }
2498                 spin_unlock(&delayed_refs->lock);
2499                 schedule_timeout(1);
2500                 goto again;
2501         }
2502 out:
2503         spin_unlock(&delayed_refs->lock);
2504         return 0;
2505 }
2506
2507 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2508                                 struct btrfs_root *root,
2509                                 u64 bytenr, u64 num_bytes, u64 flags,
2510                                 int is_data)
2511 {
2512         struct btrfs_delayed_extent_op *extent_op;
2513         int ret;
2514
2515         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2516         if (!extent_op)
2517                 return -ENOMEM;
2518
2519         extent_op->flags_to_set = flags;
2520         extent_op->update_flags = 1;
2521         extent_op->update_key = 0;
2522         extent_op->is_data = is_data ? 1 : 0;
2523
2524         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2525                                           num_bytes, extent_op);
2526         if (ret)
2527                 kfree(extent_op);
2528         return ret;
2529 }
2530
2531 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2532                                       struct btrfs_root *root,
2533                                       struct btrfs_path *path,
2534                                       u64 objectid, u64 offset, u64 bytenr)
2535 {
2536         struct btrfs_delayed_ref_head *head;
2537         struct btrfs_delayed_ref_node *ref;
2538         struct btrfs_delayed_data_ref *data_ref;
2539         struct btrfs_delayed_ref_root *delayed_refs;
2540         struct rb_node *node;
2541         int ret = 0;
2542
2543         ret = -ENOENT;
2544         delayed_refs = &trans->transaction->delayed_refs;
2545         spin_lock(&delayed_refs->lock);
2546         head = btrfs_find_delayed_ref_head(trans, bytenr);
2547         if (!head)
2548                 goto out;
2549
2550         if (!mutex_trylock(&head->mutex)) {
2551                 atomic_inc(&head->node.refs);
2552                 spin_unlock(&delayed_refs->lock);
2553
2554                 btrfs_release_path(path);
2555
2556                 /*
2557                  * Mutex was contended, block until it's released and let
2558                  * caller try again
2559                  */
2560                 mutex_lock(&head->mutex);
2561                 mutex_unlock(&head->mutex);
2562                 btrfs_put_delayed_ref(&head->node);
2563                 return -EAGAIN;
2564         }
2565
2566         node = rb_prev(&head->node.rb_node);
2567         if (!node)
2568                 goto out_unlock;
2569
2570         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2571
2572         if (ref->bytenr != bytenr)
2573                 goto out_unlock;
2574
2575         ret = 1;
2576         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2577                 goto out_unlock;
2578
2579         data_ref = btrfs_delayed_node_to_data_ref(ref);
2580
2581         node = rb_prev(node);
2582         if (node) {
2583                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2584                 if (ref->bytenr == bytenr)
2585                         goto out_unlock;
2586         }
2587
2588         if (data_ref->root != root->root_key.objectid ||
2589             data_ref->objectid != objectid || data_ref->offset != offset)
2590                 goto out_unlock;
2591
2592         ret = 0;
2593 out_unlock:
2594         mutex_unlock(&head->mutex);
2595 out:
2596         spin_unlock(&delayed_refs->lock);
2597         return ret;
2598 }
2599
2600 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2601                                         struct btrfs_root *root,
2602                                         struct btrfs_path *path,
2603                                         u64 objectid, u64 offset, u64 bytenr)
2604 {
2605         struct btrfs_root *extent_root = root->fs_info->extent_root;
2606         struct extent_buffer *leaf;
2607         struct btrfs_extent_data_ref *ref;
2608         struct btrfs_extent_inline_ref *iref;
2609         struct btrfs_extent_item *ei;
2610         struct btrfs_key key;
2611         u32 item_size;
2612         int ret;
2613
2614         key.objectid = bytenr;
2615         key.offset = (u64)-1;
2616         key.type = BTRFS_EXTENT_ITEM_KEY;
2617
2618         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2619         if (ret < 0)
2620                 goto out;
2621         BUG_ON(ret == 0); /* Corruption */
2622
2623         ret = -ENOENT;
2624         if (path->slots[0] == 0)
2625                 goto out;
2626
2627         path->slots[0]--;
2628         leaf = path->nodes[0];
2629         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2630
2631         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2632                 goto out;
2633
2634         ret = 1;
2635         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2636 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2637         if (item_size < sizeof(*ei)) {
2638                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2639                 goto out;
2640         }
2641 #endif
2642         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2643
2644         if (item_size != sizeof(*ei) +
2645             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2646                 goto out;
2647
2648         if (btrfs_extent_generation(leaf, ei) <=
2649             btrfs_root_last_snapshot(&root->root_item))
2650                 goto out;
2651
2652         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2653         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2654             BTRFS_EXTENT_DATA_REF_KEY)
2655                 goto out;
2656
2657         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2658         if (btrfs_extent_refs(leaf, ei) !=
2659             btrfs_extent_data_ref_count(leaf, ref) ||
2660             btrfs_extent_data_ref_root(leaf, ref) !=
2661             root->root_key.objectid ||
2662             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2663             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2664                 goto out;
2665
2666         ret = 0;
2667 out:
2668         return ret;
2669 }
2670
2671 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2672                           struct btrfs_root *root,
2673                           u64 objectid, u64 offset, u64 bytenr)
2674 {
2675         struct btrfs_path *path;
2676         int ret;
2677         int ret2;
2678
2679         path = btrfs_alloc_path();
2680         if (!path)
2681                 return -ENOENT;
2682
2683         do {
2684                 ret = check_committed_ref(trans, root, path, objectid,
2685                                           offset, bytenr);
2686                 if (ret && ret != -ENOENT)
2687                         goto out;
2688
2689                 ret2 = check_delayed_ref(trans, root, path, objectid,
2690                                          offset, bytenr);
2691         } while (ret2 == -EAGAIN);
2692
2693         if (ret2 && ret2 != -ENOENT) {
2694                 ret = ret2;
2695                 goto out;
2696         }
2697
2698         if (ret != -ENOENT || ret2 != -ENOENT)
2699                 ret = 0;
2700 out:
2701         btrfs_free_path(path);
2702         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2703                 WARN_ON(ret > 0);
2704         return ret;
2705 }
2706
2707 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2708                            struct btrfs_root *root,
2709                            struct extent_buffer *buf,
2710                            int full_backref, int inc, int for_cow)
2711 {
2712         u64 bytenr;
2713         u64 num_bytes;
2714         u64 parent;
2715         u64 ref_root;
2716         u32 nritems;
2717         struct btrfs_key key;
2718         struct btrfs_file_extent_item *fi;
2719         int i;
2720         int level;
2721         int ret = 0;
2722         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2723                             u64, u64, u64, u64, u64, u64, int);
2724
2725         ref_root = btrfs_header_owner(buf);
2726         nritems = btrfs_header_nritems(buf);
2727         level = btrfs_header_level(buf);
2728
2729         if (!root->ref_cows && level == 0)
2730                 return 0;
2731
2732         if (inc)
2733                 process_func = btrfs_inc_extent_ref;
2734         else
2735                 process_func = btrfs_free_extent;
2736
2737         if (full_backref)
2738                 parent = buf->start;
2739         else
2740                 parent = 0;
2741
2742         for (i = 0; i < nritems; i++) {
2743                 if (level == 0) {
2744                         btrfs_item_key_to_cpu(buf, &key, i);
2745                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2746                                 continue;
2747                         fi = btrfs_item_ptr(buf, i,
2748                                             struct btrfs_file_extent_item);
2749                         if (btrfs_file_extent_type(buf, fi) ==
2750                             BTRFS_FILE_EXTENT_INLINE)
2751                                 continue;
2752                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2753                         if (bytenr == 0)
2754                                 continue;
2755
2756                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2757                         key.offset -= btrfs_file_extent_offset(buf, fi);
2758                         ret = process_func(trans, root, bytenr, num_bytes,
2759                                            parent, ref_root, key.objectid,
2760                                            key.offset, for_cow);
2761                         if (ret)
2762                                 goto fail;
2763                 } else {
2764                         bytenr = btrfs_node_blockptr(buf, i);
2765                         num_bytes = btrfs_level_size(root, level - 1);
2766                         ret = process_func(trans, root, bytenr, num_bytes,
2767                                            parent, ref_root, level - 1, 0,
2768                                            for_cow);
2769                         if (ret)
2770                                 goto fail;
2771                 }
2772         }
2773         return 0;
2774 fail:
2775         return ret;
2776 }
2777
2778 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2779                   struct extent_buffer *buf, int full_backref, int for_cow)
2780 {
2781         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2782 }
2783
2784 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2785                   struct extent_buffer *buf, int full_backref, int for_cow)
2786 {
2787         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2788 }
2789
2790 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2791                                  struct btrfs_root *root,
2792                                  struct btrfs_path *path,
2793                                  struct btrfs_block_group_cache *cache)
2794 {
2795         int ret;
2796         struct btrfs_root *extent_root = root->fs_info->extent_root;
2797         unsigned long bi;
2798         struct extent_buffer *leaf;
2799
2800         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2801         if (ret < 0)
2802                 goto fail;
2803         BUG_ON(ret); /* Corruption */
2804
2805         leaf = path->nodes[0];
2806         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2807         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2808         btrfs_mark_buffer_dirty(leaf);
2809         btrfs_release_path(path);
2810 fail:
2811         if (ret) {
2812                 btrfs_abort_transaction(trans, root, ret);
2813                 return ret;
2814         }
2815         return 0;
2816
2817 }
2818
2819 static struct btrfs_block_group_cache *
2820 next_block_group(struct btrfs_root *root,
2821                  struct btrfs_block_group_cache *cache)
2822 {
2823         struct rb_node *node;
2824         spin_lock(&root->fs_info->block_group_cache_lock);
2825         node = rb_next(&cache->cache_node);
2826         btrfs_put_block_group(cache);
2827         if (node) {
2828                 cache = rb_entry(node, struct btrfs_block_group_cache,
2829                                  cache_node);
2830                 btrfs_get_block_group(cache);
2831         } else
2832                 cache = NULL;
2833         spin_unlock(&root->fs_info->block_group_cache_lock);
2834         return cache;
2835 }
2836
2837 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2838                             struct btrfs_trans_handle *trans,
2839                             struct btrfs_path *path)
2840 {
2841         struct btrfs_root *root = block_group->fs_info->tree_root;
2842         struct inode *inode = NULL;
2843         u64 alloc_hint = 0;
2844         int dcs = BTRFS_DC_ERROR;
2845         int num_pages = 0;
2846         int retries = 0;
2847         int ret = 0;
2848
2849         /*
2850          * If this block group is smaller than 100 megs don't bother caching the
2851          * block group.
2852          */
2853         if (block_group->key.offset < (100 * 1024 * 1024)) {
2854                 spin_lock(&block_group->lock);
2855                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2856                 spin_unlock(&block_group->lock);
2857                 return 0;
2858         }
2859
2860 again:
2861         inode = lookup_free_space_inode(root, block_group, path);
2862         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2863                 ret = PTR_ERR(inode);
2864                 btrfs_release_path(path);
2865                 goto out;
2866         }
2867
2868         if (IS_ERR(inode)) {
2869                 BUG_ON(retries);
2870                 retries++;
2871
2872                 if (block_group->ro)
2873                         goto out_free;
2874
2875                 ret = create_free_space_inode(root, trans, block_group, path);
2876                 if (ret)
2877                         goto out_free;
2878                 goto again;
2879         }
2880
2881         /* We've already setup this transaction, go ahead and exit */
2882         if (block_group->cache_generation == trans->transid &&
2883             i_size_read(inode)) {
2884                 dcs = BTRFS_DC_SETUP;
2885                 goto out_put;
2886         }
2887
2888         /*
2889          * We want to set the generation to 0, that way if anything goes wrong
2890          * from here on out we know not to trust this cache when we load up next
2891          * time.
2892          */
2893         BTRFS_I(inode)->generation = 0;
2894         ret = btrfs_update_inode(trans, root, inode);
2895         WARN_ON(ret);
2896
2897         if (i_size_read(inode) > 0) {
2898                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2899                                                       inode);
2900                 if (ret)
2901                         goto out_put;
2902         }
2903
2904         spin_lock(&block_group->lock);
2905         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2906                 /* We're not cached, don't bother trying to write stuff out */
2907                 dcs = BTRFS_DC_WRITTEN;
2908                 spin_unlock(&block_group->lock);
2909                 goto out_put;
2910         }
2911         spin_unlock(&block_group->lock);
2912
2913         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2914         if (!num_pages)
2915                 num_pages = 1;
2916
2917         /*
2918          * Just to make absolutely sure we have enough space, we're going to
2919          * preallocate 12 pages worth of space for each block group.  In
2920          * practice we ought to use at most 8, but we need extra space so we can
2921          * add our header and have a terminator between the extents and the
2922          * bitmaps.
2923          */
2924         num_pages *= 16;
2925         num_pages *= PAGE_CACHE_SIZE;
2926
2927         ret = btrfs_check_data_free_space(inode, num_pages);
2928         if (ret)
2929                 goto out_put;
2930
2931         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2932                                               num_pages, num_pages,
2933                                               &alloc_hint);
2934         if (!ret)
2935                 dcs = BTRFS_DC_SETUP;
2936         btrfs_free_reserved_data_space(inode, num_pages);
2937
2938 out_put:
2939         iput(inode);
2940 out_free:
2941         btrfs_release_path(path);
2942 out:
2943         spin_lock(&block_group->lock);
2944         if (!ret && dcs == BTRFS_DC_SETUP)
2945                 block_group->cache_generation = trans->transid;
2946         block_group->disk_cache_state = dcs;
2947         spin_unlock(&block_group->lock);
2948
2949         return ret;
2950 }
2951
2952 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2953                                    struct btrfs_root *root)
2954 {
2955         struct btrfs_block_group_cache *cache;
2956         int err = 0;
2957         struct btrfs_path *path;
2958         u64 last = 0;
2959
2960         path = btrfs_alloc_path();
2961         if (!path)
2962                 return -ENOMEM;
2963
2964 again:
2965         while (1) {
2966                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2967                 while (cache) {
2968                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2969                                 break;
2970                         cache = next_block_group(root, cache);
2971                 }
2972                 if (!cache) {
2973                         if (last == 0)
2974                                 break;
2975                         last = 0;
2976                         continue;
2977                 }
2978                 err = cache_save_setup(cache, trans, path);
2979                 last = cache->key.objectid + cache->key.offset;
2980                 btrfs_put_block_group(cache);
2981         }
2982
2983         while (1) {
2984                 if (last == 0) {
2985                         err = btrfs_run_delayed_refs(trans, root,
2986                                                      (unsigned long)-1);
2987                         if (err) /* File system offline */
2988                                 goto out;
2989                 }
2990
2991                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2992                 while (cache) {
2993                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2994                                 btrfs_put_block_group(cache);
2995                                 goto again;
2996                         }
2997
2998                         if (cache->dirty)
2999                                 break;
3000                         cache = next_block_group(root, cache);
3001                 }
3002                 if (!cache) {
3003                         if (last == 0)
3004                                 break;
3005                         last = 0;
3006                         continue;
3007                 }
3008
3009                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3010                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3011                 cache->dirty = 0;
3012                 last = cache->key.objectid + cache->key.offset;
3013
3014                 err = write_one_cache_group(trans, root, path, cache);
3015                 if (err) /* File system offline */
3016                         goto out;
3017
3018                 btrfs_put_block_group(cache);
3019         }
3020
3021         while (1) {
3022                 /*
3023                  * I don't think this is needed since we're just marking our
3024                  * preallocated extent as written, but just in case it can't
3025                  * hurt.
3026                  */
3027                 if (last == 0) {
3028                         err = btrfs_run_delayed_refs(trans, root,
3029                                                      (unsigned long)-1);
3030                         if (err) /* File system offline */
3031                                 goto out;
3032                 }
3033
3034                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3035                 while (cache) {
3036                         /*
3037                          * Really this shouldn't happen, but it could if we
3038                          * couldn't write the entire preallocated extent and
3039                          * splitting the extent resulted in a new block.
3040                          */
3041                         if (cache->dirty) {
3042                                 btrfs_put_block_group(cache);
3043                                 goto again;
3044                         }
3045                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3046                                 break;
3047                         cache = next_block_group(root, cache);
3048                 }
3049                 if (!cache) {
3050                         if (last == 0)
3051                                 break;
3052                         last = 0;
3053                         continue;
3054                 }
3055
3056                 err = btrfs_write_out_cache(root, trans, cache, path);
3057
3058                 /*
3059                  * If we didn't have an error then the cache state is still
3060                  * NEED_WRITE, so we can set it to WRITTEN.
3061                  */
3062                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3063                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3064                 last = cache->key.objectid + cache->key.offset;
3065                 btrfs_put_block_group(cache);
3066         }
3067 out:
3068
3069         btrfs_free_path(path);
3070         return err;
3071 }
3072
3073 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3074 {
3075         struct btrfs_block_group_cache *block_group;
3076         int readonly = 0;
3077
3078         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3079         if (!block_group || block_group->ro)
3080                 readonly = 1;
3081         if (block_group)
3082                 btrfs_put_block_group(block_group);
3083         return readonly;
3084 }
3085
3086 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3087                              u64 total_bytes, u64 bytes_used,
3088                              struct btrfs_space_info **space_info)
3089 {
3090         struct btrfs_space_info *found;
3091         int i;
3092         int factor;
3093
3094         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3095                      BTRFS_BLOCK_GROUP_RAID10))
3096                 factor = 2;
3097         else
3098                 factor = 1;
3099
3100         found = __find_space_info(info, flags);
3101         if (found) {
3102                 spin_lock(&found->lock);
3103                 found->total_bytes += total_bytes;
3104                 found->disk_total += total_bytes * factor;
3105                 found->bytes_used += bytes_used;
3106                 found->disk_used += bytes_used * factor;
3107                 found->full = 0;
3108                 spin_unlock(&found->lock);
3109                 *space_info = found;
3110                 return 0;
3111         }
3112         found = kzalloc(sizeof(*found), GFP_NOFS);
3113         if (!found)
3114                 return -ENOMEM;
3115
3116         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3117                 INIT_LIST_HEAD(&found->block_groups[i]);
3118         init_rwsem(&found->groups_sem);
3119         spin_lock_init(&found->lock);
3120         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3121         found->total_bytes = total_bytes;
3122         found->disk_total = total_bytes * factor;
3123         found->bytes_used = bytes_used;
3124         found->disk_used = bytes_used * factor;
3125         found->bytes_pinned = 0;
3126         found->bytes_reserved = 0;
3127         found->bytes_readonly = 0;
3128         found->bytes_may_use = 0;
3129         found->full = 0;
3130         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3131         found->chunk_alloc = 0;
3132         found->flush = 0;
3133         init_waitqueue_head(&found->wait);
3134         *space_info = found;
3135         list_add_rcu(&found->list, &info->space_info);
3136         return 0;
3137 }
3138
3139 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3140 {
3141         u64 extra_flags = chunk_to_extended(flags) &
3142                                 BTRFS_EXTENDED_PROFILE_MASK;
3143
3144         if (flags & BTRFS_BLOCK_GROUP_DATA)
3145                 fs_info->avail_data_alloc_bits |= extra_flags;
3146         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3147                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3148         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3149                 fs_info->avail_system_alloc_bits |= extra_flags;
3150 }
3151
3152 /*
3153  * returns target flags in extended format or 0 if restripe for this
3154  * chunk_type is not in progress
3155  */
3156 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3157 {
3158         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3159         u64 target = 0;
3160
3161         BUG_ON(!mutex_is_locked(&fs_info->volume_mutex) &&
3162                !spin_is_locked(&fs_info->balance_lock));
3163
3164         if (!bctl)
3165                 return 0;
3166
3167         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3168             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3169                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3170         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3171                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3172                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3173         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3174                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3175                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3176         }
3177
3178         return target;
3179 }
3180
3181 /*
3182  * @flags: available profiles in extended format (see ctree.h)
3183  *
3184  * Returns reduced profile in chunk format.  If profile changing is in
3185  * progress (either running or paused) picks the target profile (if it's
3186  * already available), otherwise falls back to plain reducing.
3187  */
3188 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3189 {
3190         /*
3191          * we add in the count of missing devices because we want
3192          * to make sure that any RAID levels on a degraded FS
3193          * continue to be honored.
3194          */
3195         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3196                 root->fs_info->fs_devices->missing_devices;
3197         u64 target;
3198
3199         /*
3200          * see if restripe for this chunk_type is in progress, if so
3201          * try to reduce to the target profile
3202          */
3203         spin_lock(&root->fs_info->balance_lock);
3204         target = get_restripe_target(root->fs_info, flags);
3205         if (target) {
3206                 /* pick target profile only if it's already available */
3207                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3208                         spin_unlock(&root->fs_info->balance_lock);
3209                         return extended_to_chunk(target);
3210                 }
3211         }
3212         spin_unlock(&root->fs_info->balance_lock);
3213
3214         if (num_devices == 1)
3215                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3216         if (num_devices < 4)
3217                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3218
3219         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3220             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3221                       BTRFS_BLOCK_GROUP_RAID10))) {
3222                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3223         }
3224
3225         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3226             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3227                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3228         }
3229
3230         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3231             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3232              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3233              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3234                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3235         }
3236
3237         return extended_to_chunk(flags);
3238 }
3239
3240 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3241 {
3242         if (flags & BTRFS_BLOCK_GROUP_DATA)
3243                 flags |= root->fs_info->avail_data_alloc_bits;
3244         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3245                 flags |= root->fs_info->avail_system_alloc_bits;
3246         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3247                 flags |= root->fs_info->avail_metadata_alloc_bits;
3248
3249         return btrfs_reduce_alloc_profile(root, flags);
3250 }
3251
3252 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3253 {
3254         u64 flags;
3255
3256         if (data)
3257                 flags = BTRFS_BLOCK_GROUP_DATA;
3258         else if (root == root->fs_info->chunk_root)
3259                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3260         else
3261                 flags = BTRFS_BLOCK_GROUP_METADATA;
3262
3263         return get_alloc_profile(root, flags);
3264 }
3265
3266 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3267 {
3268         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3269                                                        BTRFS_BLOCK_GROUP_DATA);
3270 }
3271
3272 /*
3273  * This will check the space that the inode allocates from to make sure we have
3274  * enough space for bytes.
3275  */
3276 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3277 {
3278         struct btrfs_space_info *data_sinfo;
3279         struct btrfs_root *root = BTRFS_I(inode)->root;
3280         u64 used;
3281         int ret = 0, committed = 0, alloc_chunk = 1;
3282
3283         /* make sure bytes are sectorsize aligned */
3284         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3285
3286         if (root == root->fs_info->tree_root ||
3287             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3288                 alloc_chunk = 0;
3289                 committed = 1;
3290         }
3291
3292         data_sinfo = BTRFS_I(inode)->space_info;
3293         if (!data_sinfo)
3294                 goto alloc;
3295
3296 again:
3297         /* make sure we have enough space to handle the data first */
3298         spin_lock(&data_sinfo->lock);
3299         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3300                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3301                 data_sinfo->bytes_may_use;
3302
3303         if (used + bytes > data_sinfo->total_bytes) {
3304                 struct btrfs_trans_handle *trans;
3305
3306                 /*
3307                  * if we don't have enough free bytes in this space then we need
3308                  * to alloc a new chunk.
3309                  */
3310                 if (!data_sinfo->full && alloc_chunk) {
3311                         u64 alloc_target;
3312
3313                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3314                         spin_unlock(&data_sinfo->lock);
3315 alloc:
3316                         alloc_target = btrfs_get_alloc_profile(root, 1);
3317                         trans = btrfs_join_transaction(root);
3318                         if (IS_ERR(trans))
3319                                 return PTR_ERR(trans);
3320
3321                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3322                                              bytes + 2 * 1024 * 1024,
3323                                              alloc_target,
3324                                              CHUNK_ALLOC_NO_FORCE);
3325                         btrfs_end_transaction(trans, root);
3326                         if (ret < 0) {
3327                                 if (ret != -ENOSPC)
3328                                         return ret;
3329                                 else
3330                                         goto commit_trans;
3331                         }
3332
3333                         if (!data_sinfo) {
3334                                 btrfs_set_inode_space_info(root, inode);
3335                                 data_sinfo = BTRFS_I(inode)->space_info;
3336                         }
3337                         goto again;
3338                 }
3339
3340                 /*
3341                  * If we have less pinned bytes than we want to allocate then
3342                  * don't bother committing the transaction, it won't help us.
3343                  */
3344                 if (data_sinfo->bytes_pinned < bytes)
3345                         committed = 1;
3346                 spin_unlock(&data_sinfo->lock);
3347
3348                 /* commit the current transaction and try again */
3349 commit_trans:
3350                 if (!committed &&
3351                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3352                         committed = 1;
3353                         trans = btrfs_join_transaction(root);
3354                         if (IS_ERR(trans))
3355                                 return PTR_ERR(trans);
3356                         ret = btrfs_commit_transaction(trans, root);
3357                         if (ret)
3358                                 return ret;
3359                         goto again;
3360                 }
3361
3362                 return -ENOSPC;
3363         }
3364         data_sinfo->bytes_may_use += bytes;
3365         trace_btrfs_space_reservation(root->fs_info, "space_info",
3366                                       (u64)(unsigned long)data_sinfo,
3367                                       bytes, 1);
3368         spin_unlock(&data_sinfo->lock);
3369
3370         return 0;
3371 }
3372
3373 /*
3374  * Called if we need to clear a data reservation for this inode.
3375  */
3376 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3377 {
3378         struct btrfs_root *root = BTRFS_I(inode)->root;
3379         struct btrfs_space_info *data_sinfo;
3380
3381         /* make sure bytes are sectorsize aligned */
3382         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3383
3384         data_sinfo = BTRFS_I(inode)->space_info;
3385         spin_lock(&data_sinfo->lock);
3386         data_sinfo->bytes_may_use -= bytes;
3387         trace_btrfs_space_reservation(root->fs_info, "space_info",
3388                                       (u64)(unsigned long)data_sinfo,
3389                                       bytes, 0);
3390         spin_unlock(&data_sinfo->lock);
3391 }
3392
3393 static void force_metadata_allocation(struct btrfs_fs_info *info)
3394 {
3395         struct list_head *head = &info->space_info;
3396         struct btrfs_space_info *found;
3397
3398         rcu_read_lock();
3399         list_for_each_entry_rcu(found, head, list) {
3400                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3401                         found->force_alloc = CHUNK_ALLOC_FORCE;
3402         }
3403         rcu_read_unlock();
3404 }
3405
3406 static int should_alloc_chunk(struct btrfs_root *root,
3407                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3408                               int force)
3409 {
3410         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3411         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3412         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3413         u64 thresh;
3414
3415         if (force == CHUNK_ALLOC_FORCE)
3416                 return 1;
3417
3418         /*
3419          * We need to take into account the global rsv because for all intents
3420          * and purposes it's used space.  Don't worry about locking the
3421          * global_rsv, it doesn't change except when the transaction commits.
3422          */
3423         num_allocated += global_rsv->size;
3424
3425         /*
3426          * in limited mode, we want to have some free space up to
3427          * about 1% of the FS size.
3428          */
3429         if (force == CHUNK_ALLOC_LIMITED) {
3430                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3431                 thresh = max_t(u64, 64 * 1024 * 1024,
3432                                div_factor_fine(thresh, 1));
3433
3434                 if (num_bytes - num_allocated < thresh)
3435                         return 1;
3436         }
3437         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3438
3439         /* 256MB or 2% of the FS */
3440         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3441         /* system chunks need a much small threshold */
3442         if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
3443                 thresh = 32 * 1024 * 1024;
3444
3445         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3446                 return 0;
3447         return 1;
3448 }
3449
3450 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3451                           struct btrfs_root *extent_root, u64 alloc_bytes,
3452                           u64 flags, int force)
3453 {
3454         struct btrfs_space_info *space_info;
3455         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3456         int wait_for_alloc = 0;
3457         int ret = 0;
3458
3459         space_info = __find_space_info(extent_root->fs_info, flags);
3460         if (!space_info) {
3461                 ret = update_space_info(extent_root->fs_info, flags,
3462                                         0, 0, &space_info);
3463                 BUG_ON(ret); /* -ENOMEM */
3464         }
3465         BUG_ON(!space_info); /* Logic error */
3466
3467 again:
3468         spin_lock(&space_info->lock);
3469         if (force < space_info->force_alloc)
3470                 force = space_info->force_alloc;
3471         if (space_info->full) {
3472                 spin_unlock(&space_info->lock);
3473                 return 0;
3474         }
3475
3476         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3477                 spin_unlock(&space_info->lock);
3478                 return 0;
3479         } else if (space_info->chunk_alloc) {
3480                 wait_for_alloc = 1;
3481         } else {
3482                 space_info->chunk_alloc = 1;
3483         }
3484
3485         spin_unlock(&space_info->lock);
3486
3487         mutex_lock(&fs_info->chunk_mutex);
3488
3489         /*
3490          * The chunk_mutex is held throughout the entirety of a chunk
3491          * allocation, so once we've acquired the chunk_mutex we know that the
3492          * other guy is done and we need to recheck and see if we should
3493          * allocate.
3494          */
3495         if (wait_for_alloc) {
3496                 mutex_unlock(&fs_info->chunk_mutex);
3497                 wait_for_alloc = 0;
3498                 goto again;
3499         }
3500
3501         /*
3502          * If we have mixed data/metadata chunks we want to make sure we keep
3503          * allocating mixed chunks instead of individual chunks.
3504          */
3505         if (btrfs_mixed_space_info(space_info))
3506                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3507
3508         /*
3509          * if we're doing a data chunk, go ahead and make sure that
3510          * we keep a reasonable number of metadata chunks allocated in the
3511          * FS as well.
3512          */
3513         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3514                 fs_info->data_chunk_allocations++;
3515                 if (!(fs_info->data_chunk_allocations %
3516                       fs_info->metadata_ratio))
3517                         force_metadata_allocation(fs_info);
3518         }
3519
3520         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3521         if (ret < 0 && ret != -ENOSPC)
3522                 goto out;
3523
3524         spin_lock(&space_info->lock);
3525         if (ret)
3526                 space_info->full = 1;
3527         else
3528                 ret = 1;
3529
3530         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3531         space_info->chunk_alloc = 0;
3532         spin_unlock(&space_info->lock);
3533 out:
3534         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3535         return ret;
3536 }
3537
3538 /*
3539  * shrink metadata reservation for delalloc
3540  */
3541 static int shrink_delalloc(struct btrfs_root *root, u64 to_reclaim,
3542                            bool wait_ordered)
3543 {
3544         struct btrfs_block_rsv *block_rsv;
3545         struct btrfs_space_info *space_info;
3546         struct btrfs_trans_handle *trans;
3547         u64 reserved;
3548         u64 max_reclaim;
3549         u64 reclaimed = 0;
3550         long time_left;
3551         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3552         int loops = 0;
3553         unsigned long progress;
3554
3555         trans = (struct btrfs_trans_handle *)current->journal_info;
3556         block_rsv = &root->fs_info->delalloc_block_rsv;
3557         space_info = block_rsv->space_info;
3558
3559         smp_mb();
3560         reserved = space_info->bytes_may_use;
3561         progress = space_info->reservation_progress;
3562
3563         if (reserved == 0)
3564                 return 0;
3565
3566         smp_mb();
3567         if (root->fs_info->delalloc_bytes == 0) {
3568                 if (trans)
3569                         return 0;
3570                 btrfs_wait_ordered_extents(root, 0, 0);
3571                 return 0;
3572         }
3573
3574         max_reclaim = min(reserved, to_reclaim);
3575         nr_pages = max_t(unsigned long, nr_pages,
3576                          max_reclaim >> PAGE_CACHE_SHIFT);
3577         while (loops < 1024) {
3578                 /* have the flusher threads jump in and do some IO */
3579                 smp_mb();
3580                 nr_pages = min_t(unsigned long, nr_pages,
3581                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3582                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3583                                                 WB_REASON_FS_FREE_SPACE);
3584
3585                 spin_lock(&space_info->lock);
3586                 if (reserved > space_info->bytes_may_use)
3587                         reclaimed += reserved - space_info->bytes_may_use;
3588                 reserved = space_info->bytes_may_use;
3589                 spin_unlock(&space_info->lock);
3590
3591                 loops++;
3592
3593                 if (reserved == 0 || reclaimed >= max_reclaim)
3594                         break;
3595
3596                 if (trans && trans->transaction->blocked)
3597                         return -EAGAIN;
3598
3599                 if (wait_ordered && !trans) {
3600                         btrfs_wait_ordered_extents(root, 0, 0);
3601                 } else {
3602                         time_left = schedule_timeout_interruptible(1);
3603
3604                         /* We were interrupted, exit */
3605                         if (time_left)
3606                                 break;
3607                 }
3608
3609                 /* we've kicked the IO a few times, if anything has been freed,
3610                  * exit.  There is no sense in looping here for a long time
3611                  * when we really need to commit the transaction, or there are
3612                  * just too many writers without enough free space
3613                  */
3614
3615                 if (loops > 3) {
3616                         smp_mb();
3617                         if (progress != space_info->reservation_progress)
3618                                 break;
3619                 }
3620
3621         }
3622
3623         return reclaimed >= to_reclaim;
3624 }
3625
3626 /**
3627  * maybe_commit_transaction - possibly commit the transaction if its ok to
3628  * @root - the root we're allocating for
3629  * @bytes - the number of bytes we want to reserve
3630  * @force - force the commit
3631  *
3632  * This will check to make sure that committing the transaction will actually
3633  * get us somewhere and then commit the transaction if it does.  Otherwise it
3634  * will return -ENOSPC.
3635  */
3636 static int may_commit_transaction(struct btrfs_root *root,
3637                                   struct btrfs_space_info *space_info,
3638                                   u64 bytes, int force)
3639 {
3640         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3641         struct btrfs_trans_handle *trans;
3642
3643         trans = (struct btrfs_trans_handle *)current->journal_info;
3644         if (trans)
3645                 return -EAGAIN;
3646
3647         if (force)
3648                 goto commit;
3649
3650         /* See if there is enough pinned space to make this reservation */
3651         spin_lock(&space_info->lock);
3652         if (space_info->bytes_pinned >= bytes) {
3653                 spin_unlock(&space_info->lock);
3654                 goto commit;
3655         }
3656         spin_unlock(&space_info->lock);
3657
3658         /*
3659          * See if there is some space in the delayed insertion reservation for
3660          * this reservation.
3661          */
3662         if (space_info != delayed_rsv->space_info)
3663                 return -ENOSPC;
3664
3665         spin_lock(&space_info->lock);
3666         spin_lock(&delayed_rsv->lock);
3667         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3668                 spin_unlock(&delayed_rsv->lock);
3669                 spin_unlock(&space_info->lock);
3670                 return -ENOSPC;
3671         }
3672         spin_unlock(&delayed_rsv->lock);
3673         spin_unlock(&space_info->lock);
3674
3675 commit:
3676         trans = btrfs_join_transaction(root);
3677         if (IS_ERR(trans))
3678                 return -ENOSPC;
3679
3680         return btrfs_commit_transaction(trans, root);
3681 }
3682
3683 /**
3684  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3685  * @root - the root we're allocating for
3686  * @block_rsv - the block_rsv we're allocating for
3687  * @orig_bytes - the number of bytes we want
3688  * @flush - wether or not we can flush to make our reservation
3689  *
3690  * This will reserve orgi_bytes number of bytes from the space info associated
3691  * with the block_rsv.  If there is not enough space it will make an attempt to
3692  * flush out space to make room.  It will do this by flushing delalloc if
3693  * possible or committing the transaction.  If flush is 0 then no attempts to
3694  * regain reservations will be made and this will fail if there is not enough
3695  * space already.
3696  */
3697 static int reserve_metadata_bytes(struct btrfs_root *root,
3698                                   struct btrfs_block_rsv *block_rsv,
3699                                   u64 orig_bytes, int flush)
3700 {
3701         struct btrfs_space_info *space_info = block_rsv->space_info;
3702         u64 used;
3703         u64 num_bytes = orig_bytes;
3704         int retries = 0;
3705         int ret = 0;
3706         bool committed = false;
3707         bool flushing = false;
3708         bool wait_ordered = false;
3709
3710 again:
3711         ret = 0;
3712         spin_lock(&space_info->lock);
3713         /*
3714          * We only want to wait if somebody other than us is flushing and we are
3715          * actually alloed to flush.
3716          */
3717         while (flush && !flushing && space_info->flush) {
3718                 spin_unlock(&space_info->lock);
3719                 /*
3720                  * If we have a trans handle we can't wait because the flusher
3721                  * may have to commit the transaction, which would mean we would
3722                  * deadlock since we are waiting for the flusher to finish, but
3723                  * hold the current transaction open.
3724                  */
3725                 if (current->journal_info)
3726                         return -EAGAIN;
3727                 ret = wait_event_interruptible(space_info->wait,
3728                                                !space_info->flush);
3729                 /* Must have been interrupted, return */
3730                 if (ret) {
3731                         printk(KERN_DEBUG "btrfs: %s returning -EINTR\n", __func__);
3732                         return -EINTR;
3733                 }
3734
3735                 spin_lock(&space_info->lock);
3736         }
3737
3738         ret = -ENOSPC;
3739         used = space_info->bytes_used + space_info->bytes_reserved +
3740                 space_info->bytes_pinned + space_info->bytes_readonly +
3741                 space_info->bytes_may_use;
3742
3743         /*
3744          * The idea here is that we've not already over-reserved the block group
3745          * then we can go ahead and save our reservation first and then start
3746          * flushing if we need to.  Otherwise if we've already overcommitted
3747          * lets start flushing stuff first and then come back and try to make
3748          * our reservation.
3749          */
3750         if (used <= space_info->total_bytes) {
3751                 if (used + orig_bytes <= space_info->total_bytes) {
3752                         space_info->bytes_may_use += orig_bytes;
3753                         trace_btrfs_space_reservation(root->fs_info,
3754                                               "space_info",
3755                                               (u64)(unsigned long)space_info,
3756                                               orig_bytes, 1);
3757                         ret = 0;
3758                 } else {
3759                         /*
3760                          * Ok set num_bytes to orig_bytes since we aren't
3761                          * overocmmitted, this way we only try and reclaim what
3762                          * we need.
3763                          */
3764                         num_bytes = orig_bytes;
3765                 }
3766         } else {
3767                 /*
3768                  * Ok we're over committed, set num_bytes to the overcommitted
3769                  * amount plus the amount of bytes that we need for this
3770                  * reservation.
3771                  */
3772                 wait_ordered = true;
3773                 num_bytes = used - space_info->total_bytes +
3774                         (orig_bytes * (retries + 1));
3775         }
3776
3777         if (ret) {
3778                 u64 profile = btrfs_get_alloc_profile(root, 0);
3779                 u64 avail;
3780
3781                 /*
3782                  * If we have a lot of space that's pinned, don't bother doing
3783                  * the overcommit dance yet and just commit the transaction.
3784                  */
3785                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3786                 do_div(avail, 10);
3787                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3788                         space_info->flush = 1;
3789                         flushing = true;
3790                         spin_unlock(&space_info->lock);
3791                         ret = may_commit_transaction(root, space_info,
3792                                                      orig_bytes, 1);
3793                         if (ret)
3794                                 goto out;
3795                         committed = true;
3796                         goto again;
3797                 }
3798
3799                 spin_lock(&root->fs_info->free_chunk_lock);
3800                 avail = root->fs_info->free_chunk_space;
3801
3802                 /*
3803                  * If we have dup, raid1 or raid10 then only half of the free
3804                  * space is actually useable.
3805                  */
3806                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3807                                BTRFS_BLOCK_GROUP_RAID1 |
3808                                BTRFS_BLOCK_GROUP_RAID10))
3809                         avail >>= 1;
3810
3811                 /*
3812                  * If we aren't flushing don't let us overcommit too much, say
3813                  * 1/8th of the space.  If we can flush, let it overcommit up to
3814                  * 1/2 of the space.
3815                  */
3816                 if (flush)
3817                         avail >>= 3;
3818                 else
3819                         avail >>= 1;
3820                  spin_unlock(&root->fs_info->free_chunk_lock);
3821
3822                 if (used + num_bytes < space_info->total_bytes + avail) {
3823                         space_info->bytes_may_use += orig_bytes;
3824                         trace_btrfs_space_reservation(root->fs_info,
3825                                               "space_info",
3826                                               (u64)(unsigned long)space_info,
3827                                               orig_bytes, 1);
3828                         ret = 0;
3829                 } else {
3830                         wait_ordered = true;
3831                 }
3832         }
3833
3834         /*
3835          * Couldn't make our reservation, save our place so while we're trying
3836          * to reclaim space we can actually use it instead of somebody else
3837          * stealing it from us.
3838          */
3839         if (ret && flush) {
3840                 flushing = true;
3841                 space_info->flush = 1;
3842         }
3843
3844         spin_unlock(&space_info->lock);
3845
3846         if (!ret || !flush)
3847                 goto out;
3848
3849         /*
3850          * We do synchronous shrinking since we don't actually unreserve
3851          * metadata until after the IO is completed.
3852          */
3853         ret = shrink_delalloc(root, num_bytes, wait_ordered);
3854         if (ret < 0)
3855                 goto out;
3856
3857         ret = 0;
3858
3859         /*
3860          * So if we were overcommitted it's possible that somebody else flushed
3861          * out enough space and we simply didn't have enough space to reclaim,
3862          * so go back around and try again.
3863          */
3864         if (retries < 2) {
3865                 wait_ordered = true;
3866                 retries++;
3867                 goto again;
3868         }
3869
3870         ret = -ENOSPC;
3871         if (committed)
3872                 goto out;
3873
3874         ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3875         if (!ret) {
3876                 committed = true;
3877                 goto again;
3878         }
3879
3880 out:
3881         if (flushing) {
3882                 spin_lock(&space_info->lock);
3883                 space_info->flush = 0;
3884                 wake_up_all(&space_info->wait);
3885                 spin_unlock(&space_info->lock);
3886         }
3887         return ret;
3888 }
3889
3890 static struct btrfs_block_rsv *get_block_rsv(
3891                                         const struct btrfs_trans_handle *trans,
3892                                         const struct btrfs_root *root)
3893 {
3894         struct btrfs_block_rsv *block_rsv = NULL;
3895
3896         if (root->ref_cows || root == root->fs_info->csum_root)
3897                 block_rsv = trans->block_rsv;
3898
3899         if (!block_rsv)
3900                 block_rsv = root->block_rsv;
3901
3902         if (!block_rsv)
3903                 block_rsv = &root->fs_info->empty_block_rsv;
3904
3905         return block_rsv;
3906 }
3907
3908 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3909                                u64 num_bytes)
3910 {
3911         int ret = -ENOSPC;
3912         spin_lock(&block_rsv->lock);
3913         if (block_rsv->reserved >= num_bytes) {
3914                 block_rsv->reserved -= num_bytes;
3915                 if (block_rsv->reserved < block_rsv->size)
3916                         block_rsv->full = 0;
3917                 ret = 0;
3918         }
3919         spin_unlock(&block_rsv->lock);
3920         return ret;
3921 }
3922
3923 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3924                                 u64 num_bytes, int update_size)
3925 {
3926         spin_lock(&block_rsv->lock);
3927         block_rsv->reserved += num_bytes;
3928         if (update_size)
3929                 block_rsv->size += num_bytes;
3930         else if (block_rsv->reserved >= block_rsv->size)
3931                 block_rsv->full = 1;
3932         spin_unlock(&block_rsv->lock);
3933 }
3934
3935 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
3936                                     struct btrfs_block_rsv *block_rsv,
3937                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3938 {
3939         struct btrfs_space_info *space_info = block_rsv->space_info;
3940
3941         spin_lock(&block_rsv->lock);
3942         if (num_bytes == (u64)-1)
3943                 num_bytes = block_rsv->size;
3944         block_rsv->size -= num_bytes;
3945         if (block_rsv->reserved >= block_rsv->size) {
3946                 num_bytes = block_rsv->reserved - block_rsv->size;
3947                 block_rsv->reserved = block_rsv->size;
3948                 block_rsv->full = 1;
3949         } else {
3950                 num_bytes = 0;
3951         }
3952         spin_unlock(&block_rsv->lock);
3953
3954         if (num_bytes > 0) {
3955                 if (dest) {
3956                         spin_lock(&dest->lock);
3957                         if (!dest->full) {
3958                                 u64 bytes_to_add;
3959
3960                                 bytes_to_add = dest->size - dest->reserved;
3961                                 bytes_to_add = min(num_bytes, bytes_to_add);
3962                                 dest->reserved += bytes_to_add;
3963                                 if (dest->reserved >= dest->size)
3964                                         dest->full = 1;
3965                                 num_bytes -= bytes_to_add;
3966                         }
3967                         spin_unlock(&dest->lock);
3968                 }
3969                 if (num_bytes) {
3970                         spin_lock(&space_info->lock);
3971                         space_info->bytes_may_use -= num_bytes;
3972                         trace_btrfs_space_reservation(fs_info, "space_info",
3973                                               (u64)(unsigned long)space_info,
3974                                               num_bytes, 0);
3975                         space_info->reservation_progress++;
3976                         spin_unlock(&space_info->lock);
3977                 }
3978         }
3979 }
3980
3981 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3982                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3983 {
3984         int ret;
3985
3986         ret = block_rsv_use_bytes(src, num_bytes);
3987         if (ret)
3988                 return ret;
3989
3990         block_rsv_add_bytes(dst, num_bytes, 1);
3991         return 0;
3992 }
3993
3994 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3995 {
3996         memset(rsv, 0, sizeof(*rsv));
3997         spin_lock_init(&rsv->lock);
3998 }
3999
4000 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
4001 {
4002         struct btrfs_block_rsv *block_rsv;
4003         struct btrfs_fs_info *fs_info = root->fs_info;
4004
4005         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4006         if (!block_rsv)
4007                 return NULL;
4008
4009         btrfs_init_block_rsv(block_rsv);
4010         block_rsv->space_info = __find_space_info(fs_info,
4011                                                   BTRFS_BLOCK_GROUP_METADATA);
4012         return block_rsv;
4013 }
4014
4015 void btrfs_free_block_rsv(struct btrfs_root *root,
4016                           struct btrfs_block_rsv *rsv)
4017 {
4018         btrfs_block_rsv_release(root, rsv, (u64)-1);
4019         kfree(rsv);
4020 }
4021
4022 static inline int __block_rsv_add(struct btrfs_root *root,
4023                                   struct btrfs_block_rsv *block_rsv,
4024                                   u64 num_bytes, int flush)
4025 {
4026         int ret;
4027
4028         if (num_bytes == 0)
4029                 return 0;
4030
4031         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4032         if (!ret) {
4033                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4034                 return 0;
4035         }
4036
4037         return ret;
4038 }
4039
4040 int btrfs_block_rsv_add(struct btrfs_root *root,
4041                         struct btrfs_block_rsv *block_rsv,
4042                         u64 num_bytes)
4043 {
4044         return __block_rsv_add(root, block_rsv, num_bytes, 1);
4045 }
4046
4047 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
4048                                 struct btrfs_block_rsv *block_rsv,
4049                                 u64 num_bytes)
4050 {
4051         return __block_rsv_add(root, block_rsv, num_bytes, 0);
4052 }
4053
4054 int btrfs_block_rsv_check(struct btrfs_root *root,
4055                           struct btrfs_block_rsv *block_rsv, int min_factor)
4056 {
4057         u64 num_bytes = 0;
4058         int ret = -ENOSPC;
4059
4060         if (!block_rsv)
4061                 return 0;
4062
4063         spin_lock(&block_rsv->lock);
4064         num_bytes = div_factor(block_rsv->size, min_factor);
4065         if (block_rsv->reserved >= num_bytes)
4066                 ret = 0;
4067         spin_unlock(&block_rsv->lock);
4068
4069         return ret;
4070 }
4071
4072 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4073                                            struct btrfs_block_rsv *block_rsv,
4074                                            u64 min_reserved, int flush)
4075 {
4076         u64 num_bytes = 0;
4077         int ret = -ENOSPC;
4078
4079         if (!block_rsv)
4080                 return 0;
4081
4082         spin_lock(&block_rsv->lock);
4083         num_bytes = min_reserved;
4084         if (block_rsv->reserved >= num_bytes)
4085                 ret = 0;
4086         else
4087                 num_bytes -= block_rsv->reserved;
4088         spin_unlock(&block_rsv->lock);
4089
4090         if (!ret)
4091                 return 0;
4092
4093         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4094         if (!ret) {
4095                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4096                 return 0;
4097         }
4098
4099         return ret;
4100 }
4101
4102 int btrfs_block_rsv_refill(struct btrfs_root *root,
4103                            struct btrfs_block_rsv *block_rsv,
4104                            u64 min_reserved)
4105 {
4106         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4107 }
4108
4109 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4110                                    struct btrfs_block_rsv *block_rsv,
4111                                    u64 min_reserved)
4112 {
4113         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4114 }
4115
4116 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4117                             struct btrfs_block_rsv *dst_rsv,
4118                             u64 num_bytes)
4119 {
4120         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4121 }
4122
4123 void btrfs_block_rsv_release(struct btrfs_root *root,
4124                              struct btrfs_block_rsv *block_rsv,
4125                              u64 num_bytes)
4126 {
4127         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4128         if (global_rsv->full || global_rsv == block_rsv ||
4129             block_rsv->space_info != global_rsv->space_info)
4130                 global_rsv = NULL;
4131         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4132                                 num_bytes);
4133 }
4134
4135 /*
4136  * helper to calculate size of global block reservation.
4137  * the desired value is sum of space used by extent tree,
4138  * checksum tree and root tree
4139  */
4140 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4141 {
4142         struct btrfs_space_info *sinfo;
4143         u64 num_bytes;
4144         u64 meta_used;
4145         u64 data_used;
4146         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4147
4148         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4149         spin_lock(&sinfo->lock);
4150         data_used = sinfo->bytes_used;
4151         spin_unlock(&sinfo->lock);
4152
4153         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4154         spin_lock(&sinfo->lock);
4155         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4156                 data_used = 0;
4157         meta_used = sinfo->bytes_used;
4158         spin_unlock(&sinfo->lock);
4159
4160         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4161                     csum_size * 2;
4162         num_bytes += div64_u64(data_used + meta_used, 50);
4163
4164         if (num_bytes * 3 > meta_used)
4165                 num_bytes = div64_u64(meta_used, 3) * 2;
4166
4167         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4168 }
4169
4170 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4171 {
4172         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4173         struct btrfs_space_info *sinfo = block_rsv->space_info;
4174         u64 num_bytes;
4175
4176         num_bytes = calc_global_metadata_size(fs_info);
4177
4178         spin_lock(&block_rsv->lock);
4179         spin_lock(&sinfo->lock);
4180
4181         block_rsv->size = num_bytes;
4182
4183         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4184                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4185                     sinfo->bytes_may_use;
4186
4187         if (sinfo->total_bytes > num_bytes) {
4188                 num_bytes = sinfo->total_bytes - num_bytes;
4189                 block_rsv->reserved += num_bytes;
4190                 sinfo->bytes_may_use += num_bytes;
4191                 trace_btrfs_space_reservation(fs_info, "space_info",
4192                                       (u64)(unsigned long)sinfo, num_bytes, 1);
4193         }
4194
4195         if (block_rsv->reserved >= block_rsv->size) {
4196                 num_bytes = block_rsv->reserved - block_rsv->size;
4197                 sinfo->bytes_may_use -= num_bytes;
4198                 trace_btrfs_space_reservation(fs_info, "space_info",
4199                                       (u64)(unsigned long)sinfo, num_bytes, 0);
4200                 sinfo->reservation_progress++;
4201                 block_rsv->reserved = block_rsv->size;
4202                 block_rsv->full = 1;
4203         }
4204
4205         spin_unlock(&sinfo->lock);
4206         spin_unlock(&block_rsv->lock);
4207 }
4208
4209 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4210 {
4211         struct btrfs_space_info *space_info;
4212
4213         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4214         fs_info->chunk_block_rsv.space_info = space_info;
4215
4216         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4217         fs_info->global_block_rsv.space_info = space_info;
4218         fs_info->delalloc_block_rsv.space_info = space_info;
4219         fs_info->trans_block_rsv.space_info = space_info;
4220         fs_info->empty_block_rsv.space_info = space_info;
4221         fs_info->delayed_block_rsv.space_info = space_info;
4222
4223         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4224         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4225         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4226         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4227         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4228
4229         update_global_block_rsv(fs_info);
4230 }
4231
4232 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4233 {
4234         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4235                                 (u64)-1);
4236         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4237         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4238         WARN_ON(fs_info->trans_block_rsv.size > 0);
4239         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4240         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4241         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4242         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4243         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4244 }
4245
4246 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4247                                   struct btrfs_root *root)
4248 {
4249         if (!trans->bytes_reserved)
4250                 return;
4251
4252         trace_btrfs_space_reservation(root->fs_info, "transaction",
4253                                       (u64)(unsigned long)trans,
4254                                       trans->bytes_reserved, 0);
4255         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4256         trans->bytes_reserved = 0;
4257 }
4258
4259 /* Can only return 0 or -ENOSPC */
4260 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4261                                   struct inode *inode)
4262 {
4263         struct btrfs_root *root = BTRFS_I(inode)->root;
4264         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4265         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4266
4267         /*
4268          * We need to hold space in order to delete our orphan item once we've
4269          * added it, so this takes the reservation so we can release it later
4270          * when we are truly done with the orphan item.
4271          */
4272         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4273         trace_btrfs_space_reservation(root->fs_info, "orphan",
4274                                       btrfs_ino(inode), num_bytes, 1);
4275         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4276 }
4277
4278 void btrfs_orphan_release_metadata(struct inode *inode)
4279 {
4280         struct btrfs_root *root = BTRFS_I(inode)->root;
4281         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4282         trace_btrfs_space_reservation(root->fs_info, "orphan",
4283                                       btrfs_ino(inode), num_bytes, 0);
4284         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4285 }
4286
4287 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4288                                 struct btrfs_pending_snapshot *pending)
4289 {
4290         struct btrfs_root *root = pending->root;
4291         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4292         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4293         /*
4294          * two for root back/forward refs, two for directory entries
4295          * and one for root of the snapshot.
4296          */
4297         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4298         dst_rsv->space_info = src_rsv->space_info;
4299         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4300 }
4301
4302 /**
4303  * drop_outstanding_extent - drop an outstanding extent
4304  * @inode: the inode we're dropping the extent for
4305  *
4306  * This is called when we are freeing up an outstanding extent, either called
4307  * after an error or after an extent is written.  This will return the number of
4308  * reserved extents that need to be freed.  This must be called with
4309  * BTRFS_I(inode)->lock held.
4310  */
4311 static unsigned drop_outstanding_extent(struct inode *inode)
4312 {
4313         unsigned drop_inode_space = 0;
4314         unsigned dropped_extents = 0;
4315
4316         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4317         BTRFS_I(inode)->outstanding_extents--;
4318
4319         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4320             BTRFS_I(inode)->delalloc_meta_reserved) {
4321                 drop_inode_space = 1;
4322                 BTRFS_I(inode)->delalloc_meta_reserved = 0;
4323         }
4324
4325         /*
4326          * If we have more or the same amount of outsanding extents than we have
4327          * reserved then we need to leave the reserved extents count alone.
4328          */
4329         if (BTRFS_I(inode)->outstanding_extents >=
4330             BTRFS_I(inode)->reserved_extents)
4331                 return drop_inode_space;
4332
4333         dropped_extents = BTRFS_I(inode)->reserved_extents -
4334                 BTRFS_I(inode)->outstanding_extents;
4335         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4336         return dropped_extents + drop_inode_space;
4337 }
4338
4339 /**
4340  * calc_csum_metadata_size - return the amount of metada space that must be
4341  *      reserved/free'd for the given bytes.
4342  * @inode: the inode we're manipulating
4343  * @num_bytes: the number of bytes in question
4344  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4345  *
4346  * This adjusts the number of csum_bytes in the inode and then returns the
4347  * correct amount of metadata that must either be reserved or freed.  We
4348  * calculate how many checksums we can fit into one leaf and then divide the
4349  * number of bytes that will need to be checksumed by this value to figure out
4350  * how many checksums will be required.  If we are adding bytes then the number
4351  * may go up and we will return the number of additional bytes that must be
4352  * reserved.  If it is going down we will return the number of bytes that must
4353  * be freed.
4354  *
4355  * This must be called with BTRFS_I(inode)->lock held.
4356  */
4357 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4358                                    int reserve)
4359 {
4360         struct btrfs_root *root = BTRFS_I(inode)->root;
4361         u64 csum_size;
4362         int num_csums_per_leaf;
4363         int num_csums;
4364         int old_csums;
4365
4366         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4367             BTRFS_I(inode)->csum_bytes == 0)
4368                 return 0;
4369
4370         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4371         if (reserve)
4372                 BTRFS_I(inode)->csum_bytes += num_bytes;
4373         else
4374                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4375         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4376         num_csums_per_leaf = (int)div64_u64(csum_size,
4377                                             sizeof(struct btrfs_csum_item) +
4378                                             sizeof(struct btrfs_disk_key));
4379         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4380         num_csums = num_csums + num_csums_per_leaf - 1;
4381         num_csums = num_csums / num_csums_per_leaf;
4382
4383         old_csums = old_csums + num_csums_per_leaf - 1;
4384         old_csums = old_csums / num_csums_per_leaf;
4385
4386         /* No change, no need to reserve more */
4387         if (old_csums == num_csums)
4388                 return 0;
4389
4390         if (reserve)
4391                 return btrfs_calc_trans_metadata_size(root,
4392                                                       num_csums - old_csums);
4393
4394         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4395 }
4396
4397 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4398 {
4399         struct btrfs_root *root = BTRFS_I(inode)->root;
4400         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4401         u64 to_reserve = 0;
4402         u64 csum_bytes;
4403         unsigned nr_extents = 0;
4404         int extra_reserve = 0;
4405         int flush = 1;
4406         int ret;
4407
4408         /* Need to be holding the i_mutex here if we aren't free space cache */
4409         if (btrfs_is_free_space_inode(root, inode))
4410                 flush = 0;
4411
4412         if (flush && btrfs_transaction_in_commit(root->fs_info))
4413                 schedule_timeout(1);
4414
4415         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4416         num_bytes = ALIGN(num_bytes, root->sectorsize);
4417
4418         spin_lock(&BTRFS_I(inode)->lock);
4419         BTRFS_I(inode)->outstanding_extents++;
4420
4421         if (BTRFS_I(inode)->outstanding_extents >
4422             BTRFS_I(inode)->reserved_extents)
4423                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4424                         BTRFS_I(inode)->reserved_extents;
4425
4426         /*
4427          * Add an item to reserve for updating the inode when we complete the
4428          * delalloc io.
4429          */
4430         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
4431                 nr_extents++;
4432                 extra_reserve = 1;
4433         }
4434
4435         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4436         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4437         csum_bytes = BTRFS_I(inode)->csum_bytes;
4438         spin_unlock(&BTRFS_I(inode)->lock);
4439
4440         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4441         if (ret) {
4442                 u64 to_free = 0;
4443                 unsigned dropped;
4444
4445                 spin_lock(&BTRFS_I(inode)->lock);
4446                 dropped = drop_outstanding_extent(inode);
4447                 /*
4448                  * If the inodes csum_bytes is the same as the original
4449                  * csum_bytes then we know we haven't raced with any free()ers
4450                  * so we can just reduce our inodes csum bytes and carry on.
4451                  * Otherwise we have to do the normal free thing to account for
4452                  * the case that the free side didn't free up its reserve
4453                  * because of this outstanding reservation.
4454                  */
4455                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4456                         calc_csum_metadata_size(inode, num_bytes, 0);
4457                 else
4458                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4459                 spin_unlock(&BTRFS_I(inode)->lock);
4460                 if (dropped)
4461                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4462
4463                 if (to_free) {
4464                         btrfs_block_rsv_release(root, block_rsv, to_free);
4465                         trace_btrfs_space_reservation(root->fs_info,
4466                                                       "delalloc",
4467                                                       btrfs_ino(inode),
4468                                                       to_free, 0);
4469                 }
4470                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4471                 return ret;
4472         }
4473
4474         spin_lock(&BTRFS_I(inode)->lock);
4475         if (extra_reserve) {
4476                 BTRFS_I(inode)->delalloc_meta_reserved = 1;
4477                 nr_extents--;
4478         }
4479         BTRFS_I(inode)->reserved_extents += nr_extents;
4480         spin_unlock(&BTRFS_I(inode)->lock);
4481         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4482
4483         if (to_reserve)
4484                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4485                                               btrfs_ino(inode), to_reserve, 1);
4486         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4487
4488         return 0;
4489 }
4490
4491 /**
4492  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4493  * @inode: the inode to release the reservation for
4494  * @num_bytes: the number of bytes we're releasing
4495  *
4496  * This will release the metadata reservation for an inode.  This can be called
4497  * once we complete IO for a given set of bytes to release their metadata
4498  * reservations.
4499  */
4500 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4501 {
4502         struct btrfs_root *root = BTRFS_I(inode)->root;
4503         u64 to_free = 0;
4504         unsigned dropped;
4505
4506         num_bytes = ALIGN(num_bytes, root->sectorsize);
4507         spin_lock(&BTRFS_I(inode)->lock);
4508         dropped = drop_outstanding_extent(inode);
4509
4510         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4511         spin_unlock(&BTRFS_I(inode)->lock);
4512         if (dropped > 0)
4513                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4514
4515         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4516                                       btrfs_ino(inode), to_free, 0);
4517         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4518                                 to_free);
4519 }
4520
4521 /**
4522  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4523  * @inode: inode we're writing to
4524  * @num_bytes: the number of bytes we want to allocate
4525  *
4526  * This will do the following things
4527  *
4528  * o reserve space in the data space info for num_bytes
4529  * o reserve space in the metadata space info based on number of outstanding
4530  *   extents and how much csums will be needed
4531  * o add to the inodes ->delalloc_bytes
4532  * o add it to the fs_info's delalloc inodes list.
4533  *
4534  * This will return 0 for success and -ENOSPC if there is no space left.
4535  */
4536 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4537 {
4538         int ret;
4539
4540         ret = btrfs_check_data_free_space(inode, num_bytes);
4541         if (ret)
4542                 return ret;
4543
4544         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4545         if (ret) {
4546                 btrfs_free_reserved_data_space(inode, num_bytes);
4547                 return ret;
4548         }
4549
4550         return 0;
4551 }
4552
4553 /**
4554  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4555  * @inode: inode we're releasing space for
4556  * @num_bytes: the number of bytes we want to free up
4557  *
4558  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4559  * called in the case that we don't need the metadata AND data reservations
4560  * anymore.  So if there is an error or we insert an inline extent.
4561  *
4562  * This function will release the metadata space that was not used and will
4563  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4564  * list if there are no delalloc bytes left.
4565  */
4566 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4567 {
4568         btrfs_delalloc_release_metadata(inode, num_bytes);
4569         btrfs_free_reserved_data_space(inode, num_bytes);
4570 }
4571
4572 static int update_block_group(struct btrfs_trans_handle *trans,
4573                               struct btrfs_root *root,
4574                               u64 bytenr, u64 num_bytes, int alloc)
4575 {
4576         struct btrfs_block_group_cache *cache = NULL;
4577         struct btrfs_fs_info *info = root->fs_info;
4578         u64 total = num_bytes;
4579         u64 old_val;
4580         u64 byte_in_group;
4581         int factor;
4582
4583         /* block accounting for super block */
4584         spin_lock(&info->delalloc_lock);
4585         old_val = btrfs_super_bytes_used(info->super_copy);
4586         if (alloc)
4587                 old_val += num_bytes;
4588         else
4589                 old_val -= num_bytes;
4590         btrfs_set_super_bytes_used(info->super_copy, old_val);
4591         spin_unlock(&info->delalloc_lock);
4592
4593         while (total) {
4594                 cache = btrfs_lookup_block_group(info, bytenr);
4595                 if (!cache)
4596                         return -ENOENT;
4597                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4598                                     BTRFS_BLOCK_GROUP_RAID1 |
4599                                     BTRFS_BLOCK_GROUP_RAID10))
4600                         factor = 2;
4601                 else
4602                         factor = 1;
4603                 /*
4604                  * If this block group has free space cache written out, we
4605                  * need to make sure to load it if we are removing space.  This
4606                  * is because we need the unpinning stage to actually add the
4607                  * space back to the block group, otherwise we will leak space.
4608                  */
4609                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4610                         cache_block_group(cache, trans, NULL, 1);
4611
4612                 byte_in_group = bytenr - cache->key.objectid;
4613                 WARN_ON(byte_in_group > cache->key.offset);
4614
4615                 spin_lock(&cache->space_info->lock);
4616                 spin_lock(&cache->lock);
4617
4618                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4619                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4620                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4621
4622                 cache->dirty = 1;
4623                 old_val = btrfs_block_group_used(&cache->item);
4624                 num_bytes = min(total, cache->key.offset - byte_in_group);
4625                 if (alloc) {
4626                         old_val += num_bytes;
4627                         btrfs_set_block_group_used(&cache->item, old_val);
4628                         cache->reserved -= num_bytes;
4629                         cache->space_info->bytes_reserved -= num_bytes;
4630                         cache->space_info->bytes_used += num_bytes;
4631                         cache->space_info->disk_used += num_bytes * factor;
4632                         spin_unlock(&cache->lock);
4633                         spin_unlock(&cache->space_info->lock);
4634                 } else {
4635                         old_val -= num_bytes;
4636                         btrfs_set_block_group_used(&cache->item, old_val);
4637                         cache->pinned += num_bytes;
4638                         cache->space_info->bytes_pinned += num_bytes;
4639                         cache->space_info->bytes_used -= num_bytes;
4640                         cache->space_info->disk_used -= num_bytes * factor;
4641                         spin_unlock(&cache->lock);
4642                         spin_unlock(&cache->space_info->lock);
4643
4644                         set_extent_dirty(info->pinned_extents,
4645                                          bytenr, bytenr + num_bytes - 1,
4646                                          GFP_NOFS | __GFP_NOFAIL);
4647                 }
4648                 btrfs_put_block_group(cache);
4649                 total -= num_bytes;
4650                 bytenr += num_bytes;
4651         }
4652         return 0;
4653 }
4654
4655 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4656 {
4657         struct btrfs_block_group_cache *cache;
4658         u64 bytenr;
4659
4660         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4661         if (!cache)
4662                 return 0;
4663
4664         bytenr = cache->key.objectid;
4665         btrfs_put_block_group(cache);
4666
4667         return bytenr;
4668 }
4669
4670 static int pin_down_extent(struct btrfs_root *root,
4671                            struct btrfs_block_group_cache *cache,
4672                            u64 bytenr, u64 num_bytes, int reserved)
4673 {
4674         spin_lock(&cache->space_info->lock);
4675         spin_lock(&cache->lock);
4676         cache->pinned += num_bytes;
4677         cache->space_info->bytes_pinned += num_bytes;
4678         if (reserved) {
4679                 cache->reserved -= num_bytes;
4680                 cache->space_info->bytes_reserved -= num_bytes;
4681         }
4682         spin_unlock(&cache->lock);
4683         spin_unlock(&cache->space_info->lock);
4684
4685         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4686                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4687         return 0;
4688 }
4689
4690 /*
4691  * this function must be called within transaction
4692  */
4693 int btrfs_pin_extent(struct btrfs_root *root,
4694                      u64 bytenr, u64 num_bytes, int reserved)
4695 {
4696         struct btrfs_block_group_cache *cache;
4697
4698         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4699         BUG_ON(!cache); /* Logic error */
4700
4701         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4702
4703         btrfs_put_block_group(cache);
4704         return 0;
4705 }
4706
4707 /*
4708  * this function must be called within transaction
4709  */
4710 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4711                                     struct btrfs_root *root,
4712                                     u64 bytenr, u64 num_bytes)
4713 {
4714         struct btrfs_block_group_cache *cache;
4715
4716         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4717         BUG_ON(!cache); /* Logic error */
4718
4719         /*
4720          * pull in the free space cache (if any) so that our pin
4721          * removes the free space from the cache.  We have load_only set
4722          * to one because the slow code to read in the free extents does check
4723          * the pinned extents.
4724          */
4725         cache_block_group(cache, trans, root, 1);
4726
4727         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4728
4729         /* remove us from the free space cache (if we're there at all) */
4730         btrfs_remove_free_space(cache, bytenr, num_bytes);
4731         btrfs_put_block_group(cache);
4732         return 0;
4733 }
4734
4735 /**
4736  * btrfs_update_reserved_bytes - update the block_group and space info counters
4737  * @cache:      The cache we are manipulating
4738  * @num_bytes:  The number of bytes in question
4739  * @reserve:    One of the reservation enums
4740  *
4741  * This is called by the allocator when it reserves space, or by somebody who is
4742  * freeing space that was never actually used on disk.  For example if you
4743  * reserve some space for a new leaf in transaction A and before transaction A
4744  * commits you free that leaf, you call this with reserve set to 0 in order to
4745  * clear the reservation.
4746  *
4747  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4748  * ENOSPC accounting.  For data we handle the reservation through clearing the
4749  * delalloc bits in the io_tree.  We have to do this since we could end up
4750  * allocating less disk space for the amount of data we have reserved in the
4751  * case of compression.
4752  *
4753  * If this is a reservation and the block group has become read only we cannot
4754  * make the reservation and return -EAGAIN, otherwise this function always
4755  * succeeds.
4756  */
4757 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4758                                        u64 num_bytes, int reserve)
4759 {
4760         struct btrfs_space_info *space_info = cache->space_info;
4761         int ret = 0;
4762
4763         spin_lock(&space_info->lock);
4764         spin_lock(&cache->lock);
4765         if (reserve != RESERVE_FREE) {
4766                 if (cache->ro) {
4767                         ret = -EAGAIN;
4768                 } else {
4769                         cache->reserved += num_bytes;
4770                         space_info->bytes_reserved += num_bytes;
4771                         if (reserve == RESERVE_ALLOC) {
4772                                 trace_btrfs_space_reservation(cache->fs_info,
4773                                               "space_info",
4774                                               (u64)(unsigned long)space_info,
4775                                               num_bytes, 0);
4776                                 space_info->bytes_may_use -= num_bytes;
4777                         }
4778                 }
4779         } else {
4780                 if (cache->ro)
4781                         space_info->bytes_readonly += num_bytes;
4782                 cache->reserved -= num_bytes;
4783                 space_info->bytes_reserved -= num_bytes;
4784                 space_info->reservation_progress++;
4785         }
4786         spin_unlock(&cache->lock);
4787         spin_unlock(&space_info->lock);
4788         return ret;
4789 }
4790
4791 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4792                                 struct btrfs_root *root)
4793 {
4794         struct btrfs_fs_info *fs_info = root->fs_info;
4795         struct btrfs_caching_control *next;
4796         struct btrfs_caching_control *caching_ctl;
4797         struct btrfs_block_group_cache *cache;
4798
4799         down_write(&fs_info->extent_commit_sem);
4800
4801         list_for_each_entry_safe(caching_ctl, next,
4802                                  &fs_info->caching_block_groups, list) {
4803                 cache = caching_ctl->block_group;
4804                 if (block_group_cache_done(cache)) {
4805                         cache->last_byte_to_unpin = (u64)-1;
4806                         list_del_init(&caching_ctl->list);
4807                         put_caching_control(caching_ctl);
4808                 } else {
4809                         cache->last_byte_to_unpin = caching_ctl->progress;
4810                 }
4811         }
4812
4813         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4814                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4815         else
4816                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4817
4818         up_write(&fs_info->extent_commit_sem);
4819
4820         update_global_block_rsv(fs_info);
4821 }
4822
4823 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4824 {
4825         struct btrfs_fs_info *fs_info = root->fs_info;
4826         struct btrfs_block_group_cache *cache = NULL;
4827         u64 len;
4828
4829         while (start <= end) {
4830                 if (!cache ||
4831                     start >= cache->key.objectid + cache->key.offset) {
4832                         if (cache)
4833                                 btrfs_put_block_group(cache);
4834                         cache = btrfs_lookup_block_group(fs_info, start);
4835                         BUG_ON(!cache); /* Logic error */
4836                 }
4837
4838                 len = cache->key.objectid + cache->key.offset - start;
4839                 len = min(len, end + 1 - start);
4840
4841                 if (start < cache->last_byte_to_unpin) {
4842                         len = min(len, cache->last_byte_to_unpin - start);
4843                         btrfs_add_free_space(cache, start, len);
4844                 }
4845
4846                 start += len;
4847
4848                 spin_lock(&cache->space_info->lock);
4849                 spin_lock(&cache->lock);
4850                 cache->pinned -= len;
4851                 cache->space_info->bytes_pinned -= len;
4852                 if (cache->ro)
4853                         cache->space_info->bytes_readonly += len;
4854                 spin_unlock(&cache->lock);
4855                 spin_unlock(&cache->space_info->lock);
4856         }
4857
4858         if (cache)
4859                 btrfs_put_block_group(cache);
4860         return 0;
4861 }
4862
4863 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4864                                struct btrfs_root *root)
4865 {
4866         struct btrfs_fs_info *fs_info = root->fs_info;
4867         struct extent_io_tree *unpin;
4868         u64 start;
4869         u64 end;
4870         int ret;
4871
4872         if (trans->aborted)
4873                 return 0;
4874
4875         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4876                 unpin = &fs_info->freed_extents[1];
4877         else
4878                 unpin = &fs_info->freed_extents[0];
4879
4880         while (1) {
4881                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4882                                             EXTENT_DIRTY);
4883                 if (ret)
4884                         break;
4885
4886                 if (btrfs_test_opt(root, DISCARD))
4887                         ret = btrfs_discard_extent(root, start,
4888                                                    end + 1 - start, NULL);
4889
4890                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4891                 unpin_extent_range(root, start, end);
4892                 cond_resched();
4893         }
4894
4895         return 0;
4896 }
4897
4898 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4899                                 struct btrfs_root *root,
4900                                 u64 bytenr, u64 num_bytes, u64 parent,
4901                                 u64 root_objectid, u64 owner_objectid,
4902                                 u64 owner_offset, int refs_to_drop,
4903                                 struct btrfs_delayed_extent_op *extent_op)
4904 {
4905         struct btrfs_key key;
4906         struct btrfs_path *path;
4907         struct btrfs_fs_info *info = root->fs_info;
4908         struct btrfs_root *extent_root = info->extent_root;
4909         struct extent_buffer *leaf;
4910         struct btrfs_extent_item *ei;
4911         struct btrfs_extent_inline_ref *iref;
4912         int ret;
4913         int is_data;
4914         int extent_slot = 0;
4915         int found_extent = 0;
4916         int num_to_del = 1;
4917         u32 item_size;
4918         u64 refs;
4919
4920         path = btrfs_alloc_path();
4921         if (!path)
4922                 return -ENOMEM;
4923
4924         path->reada = 1;
4925         path->leave_spinning = 1;
4926
4927         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4928         BUG_ON(!is_data && refs_to_drop != 1);
4929
4930         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4931                                     bytenr, num_bytes, parent,
4932                                     root_objectid, owner_objectid,
4933                                     owner_offset);
4934         if (ret == 0) {
4935                 extent_slot = path->slots[0];
4936                 while (extent_slot >= 0) {
4937                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4938                                               extent_slot);
4939                         if (key.objectid != bytenr)
4940                                 break;
4941                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4942                             key.offset == num_bytes) {
4943                                 found_extent = 1;
4944                                 break;
4945                         }
4946                         if (path->slots[0] - extent_slot > 5)
4947                                 break;
4948                         extent_slot--;
4949                 }
4950 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4951                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4952                 if (found_extent && item_size < sizeof(*ei))
4953                         found_extent = 0;
4954 #endif
4955                 if (!found_extent) {
4956                         BUG_ON(iref);
4957                         ret = remove_extent_backref(trans, extent_root, path,
4958                                                     NULL, refs_to_drop,
4959                                                     is_data);
4960                         if (ret)
4961                                 goto abort;
4962                         btrfs_release_path(path);
4963                         path->leave_spinning = 1;
4964
4965                         key.objectid = bytenr;
4966                         key.type = BTRFS_EXTENT_ITEM_KEY;
4967                         key.offset = num_bytes;
4968
4969                         ret = btrfs_search_slot(trans, extent_root,
4970                                                 &key, path, -1, 1);
4971                         if (ret) {
4972                                 printk(KERN_ERR "umm, got %d back from search"
4973                                        ", was looking for %llu\n", ret,
4974                                        (unsigned long long)bytenr);
4975                                 if (ret > 0)
4976                                         btrfs_print_leaf(extent_root,
4977                                                          path->nodes[0]);
4978                         }
4979                         if (ret < 0)
4980                                 goto abort;
4981                         extent_slot = path->slots[0];
4982                 }
4983         } else if (ret == -ENOENT) {
4984                 btrfs_print_leaf(extent_root, path->nodes[0]);
4985                 WARN_ON(1);
4986                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4987                        "parent %llu root %llu  owner %llu offset %llu\n",
4988                        (unsigned long long)bytenr,
4989                        (unsigned long long)parent,
4990                        (unsigned long long)root_objectid,
4991                        (unsigned long long)owner_objectid,
4992                        (unsigned long long)owner_offset);
4993         } else {
4994                 goto abort;
4995         }
4996
4997         leaf = path->nodes[0];
4998         item_size = btrfs_item_size_nr(leaf, extent_slot);
4999 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5000         if (item_size < sizeof(*ei)) {
5001                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5002                 ret = convert_extent_item_v0(trans, extent_root, path,
5003                                              owner_objectid, 0);
5004                 if (ret < 0)
5005                         goto abort;
5006
5007                 btrfs_release_path(path);
5008                 path->leave_spinning = 1;
5009
5010                 key.objectid = bytenr;
5011                 key.type = BTRFS_EXTENT_ITEM_KEY;
5012                 key.offset = num_bytes;
5013
5014                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5015                                         -1, 1);
5016                 if (ret) {
5017                         printk(KERN_ERR "umm, got %d back from search"
5018                                ", was looking for %llu\n", ret,
5019                                (unsigned long long)bytenr);
5020                         btrfs_print_leaf(extent_root, path->nodes[0]);
5021                 }
5022                 if (ret < 0)
5023                         goto abort;
5024                 extent_slot = path->slots[0];
5025                 leaf = path->nodes[0];
5026                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5027         }
5028 #endif
5029         BUG_ON(item_size < sizeof(*ei));
5030         ei = btrfs_item_ptr(leaf, extent_slot,
5031                             struct btrfs_extent_item);
5032         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5033                 struct btrfs_tree_block_info *bi;
5034                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5035                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5036                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5037         }
5038
5039         refs = btrfs_extent_refs(leaf, ei);
5040         BUG_ON(refs < refs_to_drop);
5041         refs -= refs_to_drop;
5042
5043         if (refs > 0) {
5044                 if (extent_op)
5045                         __run_delayed_extent_op(extent_op, leaf, ei);
5046                 /*
5047                  * In the case of inline back ref, reference count will
5048                  * be updated by remove_extent_backref
5049                  */
5050                 if (iref) {
5051                         BUG_ON(!found_extent);
5052                 } else {
5053                         btrfs_set_extent_refs(leaf, ei, refs);
5054                         btrfs_mark_buffer_dirty(leaf);
5055                 }
5056                 if (found_extent) {
5057                         ret = remove_extent_backref(trans, extent_root, path,
5058                                                     iref, refs_to_drop,
5059                                                     is_data);
5060                         if (ret)
5061                                 goto abort;
5062                 }
5063         } else {
5064                 if (found_extent) {
5065                         BUG_ON(is_data && refs_to_drop !=
5066                                extent_data_ref_count(root, path, iref));
5067                         if (iref) {
5068                                 BUG_ON(path->slots[0] != extent_slot);
5069                         } else {
5070                                 BUG_ON(path->slots[0] != extent_slot + 1);
5071                                 path->slots[0] = extent_slot;
5072                                 num_to_del = 2;
5073                         }
5074                 }
5075
5076                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5077                                       num_to_del);
5078                 if (ret)
5079                         goto abort;
5080                 btrfs_release_path(path);
5081
5082                 if (is_data) {
5083                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5084                         if (ret)
5085                                 goto abort;
5086                 }
5087
5088                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5089                 if (ret)
5090                         goto abort;
5091         }
5092 out:
5093         btrfs_free_path(path);
5094         return ret;
5095
5096 abort:
5097         btrfs_abort_transaction(trans, extent_root, ret);
5098         goto out;
5099 }
5100
5101 /*
5102  * when we free an block, it is possible (and likely) that we free the last
5103  * delayed ref for that extent as well.  This searches the delayed ref tree for
5104  * a given extent, and if there are no other delayed refs to be processed, it
5105  * removes it from the tree.
5106  */
5107 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5108                                       struct btrfs_root *root, u64 bytenr)
5109 {
5110         struct btrfs_delayed_ref_head *head;
5111         struct btrfs_delayed_ref_root *delayed_refs;
5112         struct btrfs_delayed_ref_node *ref;
5113         struct rb_node *node;
5114         int ret = 0;
5115
5116         delayed_refs = &trans->transaction->delayed_refs;
5117         spin_lock(&delayed_refs->lock);
5118         head = btrfs_find_delayed_ref_head(trans, bytenr);
5119         if (!head)
5120                 goto out;
5121
5122         node = rb_prev(&head->node.rb_node);
5123         if (!node)
5124                 goto out;
5125
5126         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5127
5128         /* there are still entries for this ref, we can't drop it */
5129         if (ref->bytenr == bytenr)
5130                 goto out;
5131
5132         if (head->extent_op) {
5133                 if (!head->must_insert_reserved)
5134                         goto out;
5135                 kfree(head->extent_op);
5136                 head->extent_op = NULL;
5137         }
5138
5139         /*
5140          * waiting for the lock here would deadlock.  If someone else has it
5141          * locked they are already in the process of dropping it anyway
5142          */
5143         if (!mutex_trylock(&head->mutex))
5144                 goto out;
5145
5146         /*
5147          * at this point we have a head with no other entries.  Go
5148          * ahead and process it.
5149          */
5150         head->node.in_tree = 0;
5151         rb_erase(&head->node.rb_node, &delayed_refs->root);
5152
5153         delayed_refs->num_entries--;
5154         if (waitqueue_active(&delayed_refs->seq_wait))
5155                 wake_up(&delayed_refs->seq_wait);
5156
5157         /*
5158          * we don't take a ref on the node because we're removing it from the
5159          * tree, so we just steal the ref the tree was holding.
5160          */
5161         delayed_refs->num_heads--;
5162         if (list_empty(&head->cluster))
5163                 delayed_refs->num_heads_ready--;
5164
5165         list_del_init(&head->cluster);
5166         spin_unlock(&delayed_refs->lock);
5167
5168         BUG_ON(head->extent_op);
5169         if (head->must_insert_reserved)
5170                 ret = 1;
5171
5172         mutex_unlock(&head->mutex);
5173         btrfs_put_delayed_ref(&head->node);
5174         return ret;
5175 out:
5176         spin_unlock(&delayed_refs->lock);
5177         return 0;
5178 }
5179
5180 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5181                            struct btrfs_root *root,
5182                            struct extent_buffer *buf,
5183                            u64 parent, int last_ref, int for_cow)
5184 {
5185         struct btrfs_block_group_cache *cache = NULL;
5186         int ret;
5187
5188         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5189                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5190                                         buf->start, buf->len,
5191                                         parent, root->root_key.objectid,
5192                                         btrfs_header_level(buf),
5193                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5194                 BUG_ON(ret); /* -ENOMEM */
5195         }
5196
5197         if (!last_ref)
5198                 return;
5199
5200         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5201
5202         if (btrfs_header_generation(buf) == trans->transid) {
5203                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5204                         ret = check_ref_cleanup(trans, root, buf->start);
5205                         if (!ret)
5206                                 goto out;
5207                 }
5208
5209                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5210                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5211                         goto out;
5212                 }
5213
5214                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5215
5216                 btrfs_add_free_space(cache, buf->start, buf->len);
5217                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5218         }
5219 out:
5220         /*
5221          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5222          * anymore.
5223          */
5224         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5225         btrfs_put_block_group(cache);
5226 }
5227
5228 /* Can return -ENOMEM */
5229 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5230                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5231                       u64 owner, u64 offset, int for_cow)
5232 {
5233         int ret;
5234         struct btrfs_fs_info *fs_info = root->fs_info;
5235
5236         /*
5237          * tree log blocks never actually go into the extent allocation
5238          * tree, just update pinning info and exit early.
5239          */
5240         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5241                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5242                 /* unlocks the pinned mutex */
5243                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5244                 ret = 0;
5245         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5246                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5247                                         num_bytes,
5248                                         parent, root_objectid, (int)owner,
5249                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5250         } else {
5251                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5252                                                 num_bytes,
5253                                                 parent, root_objectid, owner,
5254                                                 offset, BTRFS_DROP_DELAYED_REF,
5255                                                 NULL, for_cow);
5256         }
5257         return ret;
5258 }
5259
5260 static u64 stripe_align(struct btrfs_root *root, u64 val)
5261 {
5262         u64 mask = ((u64)root->stripesize - 1);
5263         u64 ret = (val + mask) & ~mask;
5264         return ret;
5265 }
5266
5267 /*
5268  * when we wait for progress in the block group caching, its because
5269  * our allocation attempt failed at least once.  So, we must sleep
5270  * and let some progress happen before we try again.
5271  *
5272  * This function will sleep at least once waiting for new free space to
5273  * show up, and then it will check the block group free space numbers
5274  * for our min num_bytes.  Another option is to have it go ahead
5275  * and look in the rbtree for a free extent of a given size, but this
5276  * is a good start.
5277  */
5278 static noinline int
5279 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5280                                 u64 num_bytes)
5281 {
5282         struct btrfs_caching_control *caching_ctl;
5283         DEFINE_WAIT(wait);
5284
5285         caching_ctl = get_caching_control(cache);
5286         if (!caching_ctl)
5287                 return 0;
5288
5289         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5290                    (cache->free_space_ctl->free_space >= num_bytes));
5291
5292         put_caching_control(caching_ctl);
5293         return 0;
5294 }
5295
5296 static noinline int
5297 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5298 {
5299         struct btrfs_caching_control *caching_ctl;
5300         DEFINE_WAIT(wait);
5301
5302         caching_ctl = get_caching_control(cache);
5303         if (!caching_ctl)
5304                 return 0;
5305
5306         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5307
5308         put_caching_control(caching_ctl);
5309         return 0;
5310 }
5311
5312 static int __get_block_group_index(u64 flags)
5313 {
5314         int index;
5315
5316         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5317                 index = 0;
5318         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5319                 index = 1;
5320         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5321                 index = 2;
5322         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5323                 index = 3;
5324         else
5325                 index = 4;
5326
5327         return index;
5328 }
5329
5330 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5331 {
5332         return __get_block_group_index(cache->flags);
5333 }
5334
5335 enum btrfs_loop_type {
5336         LOOP_CACHING_NOWAIT = 0,
5337         LOOP_CACHING_WAIT = 1,
5338         LOOP_ALLOC_CHUNK = 2,
5339         LOOP_NO_EMPTY_SIZE = 3,
5340 };
5341
5342 /*
5343  * walks the btree of allocated extents and find a hole of a given size.
5344  * The key ins is changed to record the hole:
5345  * ins->objectid == block start
5346  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5347  * ins->offset == number of blocks
5348  * Any available blocks before search_start are skipped.
5349  */
5350 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5351                                      struct btrfs_root *orig_root,
5352                                      u64 num_bytes, u64 empty_size,
5353                                      u64 hint_byte, struct btrfs_key *ins,
5354                                      u64 data)
5355 {
5356         int ret = 0;
5357         struct btrfs_root *root = orig_root->fs_info->extent_root;
5358         struct btrfs_free_cluster *last_ptr = NULL;
5359         struct btrfs_block_group_cache *block_group = NULL;
5360         struct btrfs_block_group_cache *used_block_group;
5361         u64 search_start = 0;
5362         int empty_cluster = 2 * 1024 * 1024;
5363         int allowed_chunk_alloc = 0;
5364         int done_chunk_alloc = 0;
5365         struct btrfs_space_info *space_info;
5366         int loop = 0;
5367         int index = 0;
5368         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5369                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5370         bool found_uncached_bg = false;
5371         bool failed_cluster_refill = false;
5372         bool failed_alloc = false;
5373         bool use_cluster = true;
5374         bool have_caching_bg = false;
5375
5376         WARN_ON(num_bytes < root->sectorsize);
5377         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5378         ins->objectid = 0;
5379         ins->offset = 0;
5380
5381         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5382
5383         space_info = __find_space_info(root->fs_info, data);
5384         if (!space_info) {
5385                 printk(KERN_ERR "No space info for %llu\n", data);
5386                 return -ENOSPC;
5387         }
5388
5389         /*
5390          * If the space info is for both data and metadata it means we have a
5391          * small filesystem and we can't use the clustering stuff.
5392          */
5393         if (btrfs_mixed_space_info(space_info))
5394                 use_cluster = false;
5395
5396         if (orig_root->ref_cows || empty_size)
5397                 allowed_chunk_alloc = 1;
5398
5399         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5400                 last_ptr = &root->fs_info->meta_alloc_cluster;
5401                 if (!btrfs_test_opt(root, SSD))
5402                         empty_cluster = 64 * 1024;
5403         }
5404
5405         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5406             btrfs_test_opt(root, SSD)) {
5407                 last_ptr = &root->fs_info->data_alloc_cluster;
5408         }
5409
5410         if (last_ptr) {
5411                 spin_lock(&last_ptr->lock);
5412                 if (last_ptr->block_group)
5413                         hint_byte = last_ptr->window_start;
5414                 spin_unlock(&last_ptr->lock);
5415         }
5416
5417         search_start = max(search_start, first_logical_byte(root, 0));
5418         search_start = max(search_start, hint_byte);
5419
5420         if (!last_ptr)
5421                 empty_cluster = 0;
5422
5423         if (search_start == hint_byte) {
5424                 block_group = btrfs_lookup_block_group(root->fs_info,
5425                                                        search_start);
5426                 used_block_group = block_group;
5427                 /*
5428                  * we don't want to use the block group if it doesn't match our
5429                  * allocation bits, or if its not cached.
5430                  *
5431                  * However if we are re-searching with an ideal block group
5432                  * picked out then we don't care that the block group is cached.
5433                  */
5434                 if (block_group && block_group_bits(block_group, data) &&
5435                     block_group->cached != BTRFS_CACHE_NO) {
5436                         down_read(&space_info->groups_sem);
5437                         if (list_empty(&block_group->list) ||
5438                             block_group->ro) {
5439                                 /*
5440                                  * someone is removing this block group,
5441                                  * we can't jump into the have_block_group
5442                                  * target because our list pointers are not
5443                                  * valid
5444                                  */
5445                                 btrfs_put_block_group(block_group);
5446                                 up_read(&space_info->groups_sem);
5447                         } else {
5448                                 index = get_block_group_index(block_group);
5449                                 goto have_block_group;
5450                         }
5451                 } else if (block_group) {
5452                         btrfs_put_block_group(block_group);
5453                 }
5454         }
5455 search:
5456         have_caching_bg = false;
5457         down_read(&space_info->groups_sem);
5458         list_for_each_entry(block_group, &space_info->block_groups[index],
5459                             list) {
5460                 u64 offset;
5461                 int cached;
5462
5463                 used_block_group = block_group;
5464                 btrfs_get_block_group(block_group);
5465                 search_start = block_group->key.objectid;
5466
5467                 /*
5468                  * this can happen if we end up cycling through all the
5469                  * raid types, but we want to make sure we only allocate
5470                  * for the proper type.
5471                  */
5472                 if (!block_group_bits(block_group, data)) {
5473                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5474                                 BTRFS_BLOCK_GROUP_RAID1 |
5475                                 BTRFS_BLOCK_GROUP_RAID10;
5476
5477                         /*
5478                          * if they asked for extra copies and this block group
5479                          * doesn't provide them, bail.  This does allow us to
5480                          * fill raid0 from raid1.
5481                          */
5482                         if ((data & extra) && !(block_group->flags & extra))
5483                                 goto loop;
5484                 }
5485
5486 have_block_group:
5487                 cached = block_group_cache_done(block_group);
5488                 if (unlikely(!cached)) {
5489                         found_uncached_bg = true;
5490                         ret = cache_block_group(block_group, trans,
5491                                                 orig_root, 0);
5492                         BUG_ON(ret < 0);
5493                         ret = 0;
5494                 }
5495
5496                 if (unlikely(block_group->ro))
5497                         goto loop;
5498
5499                 /*
5500                  * Ok we want to try and use the cluster allocator, so
5501                  * lets look there
5502                  */
5503                 if (last_ptr) {
5504                         /*
5505                          * the refill lock keeps out other
5506                          * people trying to start a new cluster
5507                          */
5508                         spin_lock(&last_ptr->refill_lock);
5509                         used_block_group = last_ptr->block_group;
5510                         if (used_block_group != block_group &&
5511                             (!used_block_group ||
5512                              used_block_group->ro ||
5513                              !block_group_bits(used_block_group, data))) {
5514                                 used_block_group = block_group;
5515                                 goto refill_cluster;
5516                         }
5517
5518                         if (used_block_group != block_group)
5519                                 btrfs_get_block_group(used_block_group);
5520
5521                         offset = btrfs_alloc_from_cluster(used_block_group,
5522                           last_ptr, num_bytes, used_block_group->key.objectid);
5523                         if (offset) {
5524                                 /* we have a block, we're done */
5525                                 spin_unlock(&last_ptr->refill_lock);
5526                                 trace_btrfs_reserve_extent_cluster(root,
5527                                         block_group, search_start, num_bytes);
5528                                 goto checks;
5529                         }
5530
5531                         WARN_ON(last_ptr->block_group != used_block_group);
5532                         if (used_block_group != block_group) {
5533                                 btrfs_put_block_group(used_block_group);
5534                                 used_block_group = block_group;
5535                         }
5536 refill_cluster:
5537                         BUG_ON(used_block_group != block_group);
5538                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5539                          * set up a new clusters, so lets just skip it
5540                          * and let the allocator find whatever block
5541                          * it can find.  If we reach this point, we
5542                          * will have tried the cluster allocator
5543                          * plenty of times and not have found
5544                          * anything, so we are likely way too
5545                          * fragmented for the clustering stuff to find
5546                          * anything.
5547                          *
5548                          * However, if the cluster is taken from the
5549                          * current block group, release the cluster
5550                          * first, so that we stand a better chance of
5551                          * succeeding in the unclustered
5552                          * allocation.  */
5553                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5554                             last_ptr->block_group != block_group) {
5555                                 spin_unlock(&last_ptr->refill_lock);
5556                                 goto unclustered_alloc;
5557                         }
5558
5559                         /*
5560                          * this cluster didn't work out, free it and
5561                          * start over
5562                          */
5563                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5564
5565                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5566                                 spin_unlock(&last_ptr->refill_lock);
5567                                 goto unclustered_alloc;
5568                         }
5569
5570                         /* allocate a cluster in this block group */
5571                         ret = btrfs_find_space_cluster(trans, root,
5572                                                block_group, last_ptr,
5573                                                search_start, num_bytes,
5574                                                empty_cluster + empty_size);
5575                         if (ret == 0) {
5576                                 /*
5577                                  * now pull our allocation out of this
5578                                  * cluster
5579                                  */
5580                                 offset = btrfs_alloc_from_cluster(block_group,
5581                                                   last_ptr, num_bytes,
5582                                                   search_start);
5583                                 if (offset) {
5584                                         /* we found one, proceed */
5585                                         spin_unlock(&last_ptr->refill_lock);
5586                                         trace_btrfs_reserve_extent_cluster(root,
5587                                                 block_group, search_start,
5588                                                 num_bytes);
5589                                         goto checks;
5590                                 }
5591                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5592                                    && !failed_cluster_refill) {
5593                                 spin_unlock(&last_ptr->refill_lock);
5594
5595                                 failed_cluster_refill = true;
5596                                 wait_block_group_cache_progress(block_group,
5597                                        num_bytes + empty_cluster + empty_size);
5598                                 goto have_block_group;
5599                         }
5600
5601                         /*
5602                          * at this point we either didn't find a cluster
5603                          * or we weren't able to allocate a block from our
5604                          * cluster.  Free the cluster we've been trying
5605                          * to use, and go to the next block group
5606                          */
5607                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5608                         spin_unlock(&last_ptr->refill_lock);
5609                         goto loop;
5610                 }
5611
5612 unclustered_alloc:
5613                 spin_lock(&block_group->free_space_ctl->tree_lock);
5614                 if (cached &&
5615                     block_group->free_space_ctl->free_space <
5616                     num_bytes + empty_cluster + empty_size) {
5617                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5618                         goto loop;
5619                 }
5620                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5621
5622                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5623                                                     num_bytes, empty_size);
5624                 /*
5625                  * If we didn't find a chunk, and we haven't failed on this
5626                  * block group before, and this block group is in the middle of
5627                  * caching and we are ok with waiting, then go ahead and wait
5628                  * for progress to be made, and set failed_alloc to true.
5629                  *
5630                  * If failed_alloc is true then we've already waited on this
5631                  * block group once and should move on to the next block group.
5632                  */
5633                 if (!offset && !failed_alloc && !cached &&
5634                     loop > LOOP_CACHING_NOWAIT) {
5635                         wait_block_group_cache_progress(block_group,
5636                                                 num_bytes + empty_size);
5637                         failed_alloc = true;
5638                         goto have_block_group;
5639                 } else if (!offset) {
5640                         if (!cached)
5641                                 have_caching_bg = true;
5642                         goto loop;
5643                 }
5644 checks:
5645                 search_start = stripe_align(root, offset);
5646
5647                 /* move on to the next group */
5648                 if (search_start + num_bytes >
5649                     used_block_group->key.objectid + used_block_group->key.offset) {
5650                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5651                         goto loop;
5652                 }
5653
5654                 if (offset < search_start)
5655                         btrfs_add_free_space(used_block_group, offset,
5656                                              search_start - offset);
5657                 BUG_ON(offset > search_start);
5658
5659                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5660                                                   alloc_type);
5661                 if (ret == -EAGAIN) {
5662                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5663                         goto loop;
5664                 }
5665
5666                 /* we are all good, lets return */
5667                 ins->objectid = search_start;
5668                 ins->offset = num_bytes;
5669
5670                 trace_btrfs_reserve_extent(orig_root, block_group,
5671                                            search_start, num_bytes);
5672                 if (offset < search_start)
5673                         btrfs_add_free_space(used_block_group, offset,
5674                                              search_start - offset);
5675                 BUG_ON(offset > search_start);
5676                 if (used_block_group != block_group)
5677                         btrfs_put_block_group(used_block_group);
5678                 btrfs_put_block_group(block_group);
5679                 break;
5680 loop:
5681                 failed_cluster_refill = false;
5682                 failed_alloc = false;
5683                 BUG_ON(index != get_block_group_index(block_group));
5684                 if (used_block_group != block_group)
5685                         btrfs_put_block_group(used_block_group);
5686                 btrfs_put_block_group(block_group);
5687         }
5688         up_read(&space_info->groups_sem);
5689
5690         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5691                 goto search;
5692
5693         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5694                 goto search;
5695
5696         /*
5697          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5698          *                      caching kthreads as we move along
5699          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5700          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5701          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5702          *                      again
5703          */
5704         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5705                 index = 0;
5706                 loop++;
5707                 if (loop == LOOP_ALLOC_CHUNK) {
5708                        if (allowed_chunk_alloc) {
5709                                 ret = do_chunk_alloc(trans, root, num_bytes +
5710                                                      2 * 1024 * 1024, data,
5711                                                      CHUNK_ALLOC_LIMITED);
5712                                 if (ret < 0) {
5713                                         btrfs_abort_transaction(trans,
5714                                                                 root, ret);
5715                                         goto out;
5716                                 }
5717                                 allowed_chunk_alloc = 0;
5718                                 if (ret == 1)
5719                                         done_chunk_alloc = 1;
5720                         } else if (!done_chunk_alloc &&
5721                                    space_info->force_alloc ==
5722                                    CHUNK_ALLOC_NO_FORCE) {
5723                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5724                         }
5725
5726                        /*
5727                         * We didn't allocate a chunk, go ahead and drop the
5728                         * empty size and loop again.
5729                         */
5730                        if (!done_chunk_alloc)
5731                                loop = LOOP_NO_EMPTY_SIZE;
5732                 }
5733
5734                 if (loop == LOOP_NO_EMPTY_SIZE) {
5735                         empty_size = 0;
5736                         empty_cluster = 0;
5737                 }
5738
5739                 goto search;
5740         } else if (!ins->objectid) {
5741                 ret = -ENOSPC;
5742         } else if (ins->objectid) {
5743                 ret = 0;
5744         }
5745 out:
5746
5747         return ret;
5748 }
5749
5750 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5751                             int dump_block_groups)
5752 {
5753         struct btrfs_block_group_cache *cache;
5754         int index = 0;
5755
5756         spin_lock(&info->lock);
5757         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5758                (unsigned long long)info->flags,
5759                (unsigned long long)(info->total_bytes - info->bytes_used -
5760                                     info->bytes_pinned - info->bytes_reserved -
5761                                     info->bytes_readonly),
5762                (info->full) ? "" : "not ");
5763         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5764                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5765                (unsigned long long)info->total_bytes,
5766                (unsigned long long)info->bytes_used,
5767                (unsigned long long)info->bytes_pinned,
5768                (unsigned long long)info->bytes_reserved,
5769                (unsigned long long)info->bytes_may_use,
5770                (unsigned long long)info->bytes_readonly);
5771         spin_unlock(&info->lock);
5772
5773         if (!dump_block_groups)
5774                 return;
5775
5776         down_read(&info->groups_sem);
5777 again:
5778         list_for_each_entry(cache, &info->block_groups[index], list) {
5779                 spin_lock(&cache->lock);
5780                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5781                        "%llu pinned %llu reserved\n",
5782                        (unsigned long long)cache->key.objectid,
5783                        (unsigned long long)cache->key.offset,
5784                        (unsigned long long)btrfs_block_group_used(&cache->item),
5785                        (unsigned long long)cache->pinned,
5786                        (unsigned long long)cache->reserved);
5787                 btrfs_dump_free_space(cache, bytes);
5788                 spin_unlock(&cache->lock);
5789         }
5790         if (++index < BTRFS_NR_RAID_TYPES)
5791                 goto again;
5792         up_read(&info->groups_sem);
5793 }
5794
5795 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5796                          struct btrfs_root *root,
5797                          u64 num_bytes, u64 min_alloc_size,
5798                          u64 empty_size, u64 hint_byte,
5799                          struct btrfs_key *ins, u64 data)
5800 {
5801         bool final_tried = false;
5802         int ret;
5803
5804         data = btrfs_get_alloc_profile(root, data);
5805 again:
5806         /*
5807          * the only place that sets empty_size is btrfs_realloc_node, which
5808          * is not called recursively on allocations
5809          */
5810         if (empty_size || root->ref_cows) {
5811                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5812                                      num_bytes + 2 * 1024 * 1024, data,
5813                                      CHUNK_ALLOC_NO_FORCE);
5814                 if (ret < 0 && ret != -ENOSPC) {
5815                         btrfs_abort_transaction(trans, root, ret);
5816                         return ret;
5817                 }
5818         }
5819
5820         WARN_ON(num_bytes < root->sectorsize);
5821         ret = find_free_extent(trans, root, num_bytes, empty_size,
5822                                hint_byte, ins, data);
5823
5824         if (ret == -ENOSPC) {
5825                 if (!final_tried) {
5826                         num_bytes = num_bytes >> 1;
5827                         num_bytes = num_bytes & ~(root->sectorsize - 1);
5828                         num_bytes = max(num_bytes, min_alloc_size);
5829                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5830                                        num_bytes, data, CHUNK_ALLOC_FORCE);
5831                         if (ret < 0 && ret != -ENOSPC) {
5832                                 btrfs_abort_transaction(trans, root, ret);
5833                                 return ret;
5834                         }
5835                         if (num_bytes == min_alloc_size)
5836                                 final_tried = true;
5837                         goto again;
5838                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
5839                         struct btrfs_space_info *sinfo;
5840
5841                         sinfo = __find_space_info(root->fs_info, data);
5842                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
5843                                "wanted %llu\n", (unsigned long long)data,
5844                                (unsigned long long)num_bytes);
5845                         if (sinfo)
5846                                 dump_space_info(sinfo, num_bytes, 1);
5847                 }
5848         }
5849
5850         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5851
5852         return ret;
5853 }
5854
5855 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5856                                         u64 start, u64 len, int pin)
5857 {
5858         struct btrfs_block_group_cache *cache;
5859         int ret = 0;
5860
5861         cache = btrfs_lookup_block_group(root->fs_info, start);
5862         if (!cache) {
5863                 printk(KERN_ERR "Unable to find block group for %llu\n",
5864                        (unsigned long long)start);
5865                 return -ENOSPC;
5866         }
5867
5868         if (btrfs_test_opt(root, DISCARD))
5869                 ret = btrfs_discard_extent(root, start, len, NULL);
5870
5871         if (pin)
5872                 pin_down_extent(root, cache, start, len, 1);
5873         else {
5874                 btrfs_add_free_space(cache, start, len);
5875                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5876         }
5877         btrfs_put_block_group(cache);
5878
5879         trace_btrfs_reserved_extent_free(root, start, len);
5880
5881         return ret;
5882 }
5883
5884 int btrfs_free_reserved_extent(struct btrfs_root *root,
5885                                         u64 start, u64 len)
5886 {
5887         return __btrfs_free_reserved_extent(root, start, len, 0);
5888 }
5889
5890 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
5891                                        u64 start, u64 len)
5892 {
5893         return __btrfs_free_reserved_extent(root, start, len, 1);
5894 }
5895
5896 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5897                                       struct btrfs_root *root,
5898                                       u64 parent, u64 root_objectid,
5899                                       u64 flags, u64 owner, u64 offset,
5900                                       struct btrfs_key *ins, int ref_mod)
5901 {
5902         int ret;
5903         struct btrfs_fs_info *fs_info = root->fs_info;
5904         struct btrfs_extent_item *extent_item;
5905         struct btrfs_extent_inline_ref *iref;
5906         struct btrfs_path *path;
5907         struct extent_buffer *leaf;
5908         int type;
5909         u32 size;
5910
5911         if (parent > 0)
5912                 type = BTRFS_SHARED_DATA_REF_KEY;
5913         else
5914                 type = BTRFS_EXTENT_DATA_REF_KEY;
5915
5916         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5917
5918         path = btrfs_alloc_path();
5919         if (!path)
5920                 return -ENOMEM;
5921
5922         path->leave_spinning = 1;
5923         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5924                                       ins, size);
5925         if (ret) {
5926                 btrfs_free_path(path);
5927                 return ret;
5928         }
5929
5930         leaf = path->nodes[0];
5931         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5932                                      struct btrfs_extent_item);
5933         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5934         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5935         btrfs_set_extent_flags(leaf, extent_item,
5936                                flags | BTRFS_EXTENT_FLAG_DATA);
5937
5938         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5939         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5940         if (parent > 0) {
5941                 struct btrfs_shared_data_ref *ref;
5942                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5943                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5944                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5945         } else {
5946                 struct btrfs_extent_data_ref *ref;
5947                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5948                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5949                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5950                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5951                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5952         }
5953
5954         btrfs_mark_buffer_dirty(path->nodes[0]);
5955         btrfs_free_path(path);
5956
5957         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5958         if (ret) { /* -ENOENT, logic error */
5959                 printk(KERN_ERR "btrfs update block group failed for %llu "
5960                        "%llu\n", (unsigned long long)ins->objectid,
5961                        (unsigned long long)ins->offset);
5962                 BUG();
5963         }
5964         return ret;
5965 }
5966
5967 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5968                                      struct btrfs_root *root,
5969                                      u64 parent, u64 root_objectid,
5970                                      u64 flags, struct btrfs_disk_key *key,
5971                                      int level, struct btrfs_key *ins)
5972 {
5973         int ret;
5974         struct btrfs_fs_info *fs_info = root->fs_info;
5975         struct btrfs_extent_item *extent_item;
5976         struct btrfs_tree_block_info *block_info;
5977         struct btrfs_extent_inline_ref *iref;
5978         struct btrfs_path *path;
5979         struct extent_buffer *leaf;
5980         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5981
5982         path = btrfs_alloc_path();
5983         if (!path)
5984                 return -ENOMEM;
5985
5986         path->leave_spinning = 1;
5987         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5988                                       ins, size);
5989         if (ret) {
5990                 btrfs_free_path(path);
5991                 return ret;
5992         }
5993
5994         leaf = path->nodes[0];
5995         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5996                                      struct btrfs_extent_item);
5997         btrfs_set_extent_refs(leaf, extent_item, 1);
5998         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5999         btrfs_set_extent_flags(leaf, extent_item,
6000                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6001         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6002
6003         btrfs_set_tree_block_key(leaf, block_info, key);
6004         btrfs_set_tree_block_level(leaf, block_info, level);
6005
6006         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6007         if (parent > 0) {
6008                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6009                 btrfs_set_extent_inline_ref_type(leaf, iref,
6010                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6011                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6012         } else {
6013                 btrfs_set_extent_inline_ref_type(leaf, iref,
6014                                                  BTRFS_TREE_BLOCK_REF_KEY);
6015                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6016         }
6017
6018         btrfs_mark_buffer_dirty(leaf);
6019         btrfs_free_path(path);
6020
6021         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
6022         if (ret) { /* -ENOENT, logic error */
6023                 printk(KERN_ERR "btrfs update block group failed for %llu "
6024                        "%llu\n", (unsigned long long)ins->objectid,
6025                        (unsigned long long)ins->offset);
6026                 BUG();
6027         }
6028         return ret;
6029 }
6030
6031 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6032                                      struct btrfs_root *root,
6033                                      u64 root_objectid, u64 owner,
6034                                      u64 offset, struct btrfs_key *ins)
6035 {
6036         int ret;
6037
6038         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6039
6040         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6041                                          ins->offset, 0,
6042                                          root_objectid, owner, offset,
6043                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6044         return ret;
6045 }
6046
6047 /*
6048  * this is used by the tree logging recovery code.  It records that
6049  * an extent has been allocated and makes sure to clear the free
6050  * space cache bits as well
6051  */
6052 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6053                                    struct btrfs_root *root,
6054                                    u64 root_objectid, u64 owner, u64 offset,
6055                                    struct btrfs_key *ins)
6056 {
6057         int ret;
6058         struct btrfs_block_group_cache *block_group;
6059         struct btrfs_caching_control *caching_ctl;
6060         u64 start = ins->objectid;
6061         u64 num_bytes = ins->offset;
6062
6063         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6064         cache_block_group(block_group, trans, NULL, 0);
6065         caching_ctl = get_caching_control(block_group);
6066
6067         if (!caching_ctl) {
6068                 BUG_ON(!block_group_cache_done(block_group));
6069                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6070                 BUG_ON(ret); /* -ENOMEM */
6071         } else {
6072                 mutex_lock(&caching_ctl->mutex);
6073
6074                 if (start >= caching_ctl->progress) {
6075                         ret = add_excluded_extent(root, start, num_bytes);
6076                         BUG_ON(ret); /* -ENOMEM */
6077                 } else if (start + num_bytes <= caching_ctl->progress) {
6078                         ret = btrfs_remove_free_space(block_group,
6079                                                       start, num_bytes);
6080                         BUG_ON(ret); /* -ENOMEM */
6081                 } else {
6082                         num_bytes = caching_ctl->progress - start;
6083                         ret = btrfs_remove_free_space(block_group,
6084                                                       start, num_bytes);
6085                         BUG_ON(ret); /* -ENOMEM */
6086
6087                         start = caching_ctl->progress;
6088                         num_bytes = ins->objectid + ins->offset -
6089                                     caching_ctl->progress;
6090                         ret = add_excluded_extent(root, start, num_bytes);
6091                         BUG_ON(ret); /* -ENOMEM */
6092                 }
6093
6094                 mutex_unlock(&caching_ctl->mutex);
6095                 put_caching_control(caching_ctl);
6096         }
6097
6098         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6099                                           RESERVE_ALLOC_NO_ACCOUNT);
6100         BUG_ON(ret); /* logic error */
6101         btrfs_put_block_group(block_group);
6102         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6103                                          0, owner, offset, ins, 1);
6104         return ret;
6105 }
6106
6107 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6108                                             struct btrfs_root *root,
6109                                             u64 bytenr, u32 blocksize,
6110                                             int level)
6111 {
6112         struct extent_buffer *buf;
6113
6114         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6115         if (!buf)
6116                 return ERR_PTR(-ENOMEM);
6117         btrfs_set_header_generation(buf, trans->transid);
6118         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6119         btrfs_tree_lock(buf);
6120         clean_tree_block(trans, root, buf);
6121         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6122
6123         btrfs_set_lock_blocking(buf);
6124         btrfs_set_buffer_uptodate(buf);
6125
6126         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6127                 /*
6128                  * we allow two log transactions at a time, use different
6129                  * EXENT bit to differentiate dirty pages.
6130                  */
6131                 if (root->log_transid % 2 == 0)
6132                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6133                                         buf->start + buf->len - 1, GFP_NOFS);
6134                 else
6135                         set_extent_new(&root->dirty_log_pages, buf->start,
6136                                         buf->start + buf->len - 1, GFP_NOFS);
6137         } else {
6138                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6139                          buf->start + buf->len - 1, GFP_NOFS);
6140         }
6141         trans->blocks_used++;
6142         /* this returns a buffer locked for blocking */
6143         return buf;
6144 }
6145
6146 static struct btrfs_block_rsv *
6147 use_block_rsv(struct btrfs_trans_handle *trans,
6148               struct btrfs_root *root, u32 blocksize)
6149 {
6150         struct btrfs_block_rsv *block_rsv;
6151         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6152         int ret;
6153
6154         block_rsv = get_block_rsv(trans, root);
6155
6156         if (block_rsv->size == 0) {
6157                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6158                 /*
6159                  * If we couldn't reserve metadata bytes try and use some from
6160                  * the global reserve.
6161                  */
6162                 if (ret && block_rsv != global_rsv) {
6163                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6164                         if (!ret)
6165                                 return global_rsv;
6166                         return ERR_PTR(ret);
6167                 } else if (ret) {
6168                         return ERR_PTR(ret);
6169                 }
6170                 return block_rsv;
6171         }
6172
6173         ret = block_rsv_use_bytes(block_rsv, blocksize);
6174         if (!ret)
6175                 return block_rsv;
6176         if (ret) {
6177                 static DEFINE_RATELIMIT_STATE(_rs,
6178                                 DEFAULT_RATELIMIT_INTERVAL,
6179                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6180                 if (__ratelimit(&_rs)) {
6181                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6182                         WARN_ON(1);
6183                 }
6184                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6185                 if (!ret) {
6186                         return block_rsv;
6187                 } else if (ret && block_rsv != global_rsv) {
6188                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6189                         if (!ret)
6190                                 return global_rsv;
6191                 }
6192         }
6193
6194         return ERR_PTR(-ENOSPC);
6195 }
6196
6197 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6198                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6199 {
6200         block_rsv_add_bytes(block_rsv, blocksize, 0);
6201         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6202 }
6203
6204 /*
6205  * finds a free extent and does all the dirty work required for allocation
6206  * returns the key for the extent through ins, and a tree buffer for
6207  * the first block of the extent through buf.
6208  *
6209  * returns the tree buffer or NULL.
6210  */
6211 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6212                                         struct btrfs_root *root, u32 blocksize,
6213                                         u64 parent, u64 root_objectid,
6214                                         struct btrfs_disk_key *key, int level,
6215                                         u64 hint, u64 empty_size, int for_cow)
6216 {
6217         struct btrfs_key ins;
6218         struct btrfs_block_rsv *block_rsv;
6219         struct extent_buffer *buf;
6220         u64 flags = 0;
6221         int ret;
6222
6223
6224         block_rsv = use_block_rsv(trans, root, blocksize);
6225         if (IS_ERR(block_rsv))
6226                 return ERR_CAST(block_rsv);
6227
6228         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6229                                    empty_size, hint, &ins, 0);
6230         if (ret) {
6231                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6232                 return ERR_PTR(ret);
6233         }
6234
6235         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6236                                     blocksize, level);
6237         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6238
6239         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6240                 if (parent == 0)
6241                         parent = ins.objectid;
6242                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6243         } else
6244                 BUG_ON(parent > 0);
6245
6246         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6247                 struct btrfs_delayed_extent_op *extent_op;
6248                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6249                 BUG_ON(!extent_op); /* -ENOMEM */
6250                 if (key)
6251                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6252                 else
6253                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6254                 extent_op->flags_to_set = flags;
6255                 extent_op->update_key = 1;
6256                 extent_op->update_flags = 1;
6257                 extent_op->is_data = 0;
6258
6259                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6260                                         ins.objectid,
6261                                         ins.offset, parent, root_objectid,
6262                                         level, BTRFS_ADD_DELAYED_EXTENT,
6263                                         extent_op, for_cow);
6264                 BUG_ON(ret); /* -ENOMEM */
6265         }
6266         return buf;
6267 }
6268
6269 struct walk_control {
6270         u64 refs[BTRFS_MAX_LEVEL];
6271         u64 flags[BTRFS_MAX_LEVEL];
6272         struct btrfs_key update_progress;
6273         int stage;
6274         int level;
6275         int shared_level;
6276         int update_ref;
6277         int keep_locks;
6278         int reada_slot;
6279         int reada_count;
6280         int for_reloc;
6281 };
6282
6283 #define DROP_REFERENCE  1
6284 #define UPDATE_BACKREF  2
6285
6286 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6287                                      struct btrfs_root *root,
6288                                      struct walk_control *wc,
6289                                      struct btrfs_path *path)
6290 {
6291         u64 bytenr;
6292         u64 generation;
6293         u64 refs;
6294         u64 flags;
6295         u32 nritems;
6296         u32 blocksize;
6297         struct btrfs_key key;
6298         struct extent_buffer *eb;
6299         int ret;
6300         int slot;
6301         int nread = 0;
6302
6303         if (path->slots[wc->level] < wc->reada_slot) {
6304                 wc->reada_count = wc->reada_count * 2 / 3;
6305                 wc->reada_count = max(wc->reada_count, 2);
6306         } else {
6307                 wc->reada_count = wc->reada_count * 3 / 2;
6308                 wc->reada_count = min_t(int, wc->reada_count,
6309                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6310         }
6311
6312         eb = path->nodes[wc->level];
6313         nritems = btrfs_header_nritems(eb);
6314         blocksize = btrfs_level_size(root, wc->level - 1);
6315
6316         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6317                 if (nread >= wc->reada_count)
6318                         break;
6319
6320                 cond_resched();
6321                 bytenr = btrfs_node_blockptr(eb, slot);
6322                 generation = btrfs_node_ptr_generation(eb, slot);
6323
6324                 if (slot == path->slots[wc->level])
6325                         goto reada;
6326
6327                 if (wc->stage == UPDATE_BACKREF &&
6328                     generation <= root->root_key.offset)
6329                         continue;
6330
6331                 /* We don't lock the tree block, it's OK to be racy here */
6332                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6333                                                &refs, &flags);
6334                 /* We don't care about errors in readahead. */
6335                 if (ret < 0)
6336                         continue;
6337                 BUG_ON(refs == 0);
6338
6339                 if (wc->stage == DROP_REFERENCE) {
6340                         if (refs == 1)
6341                                 goto reada;
6342
6343                         if (wc->level == 1 &&
6344                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6345                                 continue;
6346                         if (!wc->update_ref ||
6347                             generation <= root->root_key.offset)
6348                                 continue;
6349                         btrfs_node_key_to_cpu(eb, &key, slot);
6350                         ret = btrfs_comp_cpu_keys(&key,
6351                                                   &wc->update_progress);
6352                         if (ret < 0)
6353                                 continue;
6354                 } else {
6355                         if (wc->level == 1 &&
6356                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6357                                 continue;
6358                 }
6359 reada:
6360                 ret = readahead_tree_block(root, bytenr, blocksize,
6361                                            generation);
6362                 if (ret)
6363                         break;
6364                 nread++;
6365         }
6366         wc->reada_slot = slot;
6367 }
6368
6369 /*
6370  * hepler to process tree block while walking down the tree.
6371  *
6372  * when wc->stage == UPDATE_BACKREF, this function updates
6373  * back refs for pointers in the block.
6374  *
6375  * NOTE: return value 1 means we should stop walking down.
6376  */
6377 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6378                                    struct btrfs_root *root,
6379                                    struct btrfs_path *path,
6380                                    struct walk_control *wc, int lookup_info)
6381 {
6382         int level = wc->level;
6383         struct extent_buffer *eb = path->nodes[level];
6384         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6385         int ret;
6386
6387         if (wc->stage == UPDATE_BACKREF &&
6388             btrfs_header_owner(eb) != root->root_key.objectid)
6389                 return 1;
6390
6391         /*
6392          * when reference count of tree block is 1, it won't increase
6393          * again. once full backref flag is set, we never clear it.
6394          */
6395         if (lookup_info &&
6396             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6397              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6398                 BUG_ON(!path->locks[level]);
6399                 ret = btrfs_lookup_extent_info(trans, root,
6400                                                eb->start, eb->len,
6401                                                &wc->refs[level],
6402                                                &wc->flags[level]);
6403                 BUG_ON(ret == -ENOMEM);
6404                 if (ret)
6405                         return ret;
6406                 BUG_ON(wc->refs[level] == 0);
6407         }
6408
6409         if (wc->stage == DROP_REFERENCE) {
6410                 if (wc->refs[level] > 1)
6411                         return 1;
6412
6413                 if (path->locks[level] && !wc->keep_locks) {
6414                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6415                         path->locks[level] = 0;
6416                 }
6417                 return 0;
6418         }
6419
6420         /* wc->stage == UPDATE_BACKREF */
6421         if (!(wc->flags[level] & flag)) {
6422                 BUG_ON(!path->locks[level]);
6423                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6424                 BUG_ON(ret); /* -ENOMEM */
6425                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6426                 BUG_ON(ret); /* -ENOMEM */
6427                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6428                                                   eb->len, flag, 0);
6429                 BUG_ON(ret); /* -ENOMEM */
6430                 wc->flags[level] |= flag;
6431         }
6432
6433         /*
6434          * the block is shared by multiple trees, so it's not good to
6435          * keep the tree lock
6436          */
6437         if (path->locks[level] && level > 0) {
6438                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6439                 path->locks[level] = 0;
6440         }
6441         return 0;
6442 }
6443
6444 /*
6445  * hepler to process tree block pointer.
6446  *
6447  * when wc->stage == DROP_REFERENCE, this function checks
6448  * reference count of the block pointed to. if the block
6449  * is shared and we need update back refs for the subtree
6450  * rooted at the block, this function changes wc->stage to
6451  * UPDATE_BACKREF. if the block is shared and there is no
6452  * need to update back, this function drops the reference
6453  * to the block.
6454  *
6455  * NOTE: return value 1 means we should stop walking down.
6456  */
6457 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6458                                  struct btrfs_root *root,
6459                                  struct btrfs_path *path,
6460                                  struct walk_control *wc, int *lookup_info)
6461 {
6462         u64 bytenr;
6463         u64 generation;
6464         u64 parent;
6465         u32 blocksize;
6466         struct btrfs_key key;
6467         struct extent_buffer *next;
6468         int level = wc->level;
6469         int reada = 0;
6470         int ret = 0;
6471
6472         generation = btrfs_node_ptr_generation(path->nodes[level],
6473                                                path->slots[level]);
6474         /*
6475          * if the lower level block was created before the snapshot
6476          * was created, we know there is no need to update back refs
6477          * for the subtree
6478          */
6479         if (wc->stage == UPDATE_BACKREF &&
6480             generation <= root->root_key.offset) {
6481                 *lookup_info = 1;
6482                 return 1;
6483         }
6484
6485         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6486         blocksize = btrfs_level_size(root, level - 1);
6487
6488         next = btrfs_find_tree_block(root, bytenr, blocksize);
6489         if (!next) {
6490                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6491                 if (!next)
6492                         return -ENOMEM;
6493                 reada = 1;
6494         }
6495         btrfs_tree_lock(next);
6496         btrfs_set_lock_blocking(next);
6497
6498         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6499                                        &wc->refs[level - 1],
6500                                        &wc->flags[level - 1]);
6501         if (ret < 0) {
6502                 btrfs_tree_unlock(next);
6503                 return ret;
6504         }
6505
6506         BUG_ON(wc->refs[level - 1] == 0);
6507         *lookup_info = 0;
6508
6509         if (wc->stage == DROP_REFERENCE) {
6510                 if (wc->refs[level - 1] > 1) {
6511                         if (level == 1 &&
6512                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6513                                 goto skip;
6514
6515                         if (!wc->update_ref ||
6516                             generation <= root->root_key.offset)
6517                                 goto skip;
6518
6519                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6520                                               path->slots[level]);
6521                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6522                         if (ret < 0)
6523                                 goto skip;
6524
6525                         wc->stage = UPDATE_BACKREF;
6526                         wc->shared_level = level - 1;
6527                 }
6528         } else {
6529                 if (level == 1 &&
6530                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6531                         goto skip;
6532         }
6533
6534         if (!btrfs_buffer_uptodate(next, generation)) {
6535                 btrfs_tree_unlock(next);
6536                 free_extent_buffer(next);
6537                 next = NULL;
6538                 *lookup_info = 1;
6539         }
6540
6541         if (!next) {
6542                 if (reada && level == 1)
6543                         reada_walk_down(trans, root, wc, path);
6544                 next = read_tree_block(root, bytenr, blocksize, generation);
6545                 if (!next)
6546                         return -EIO;
6547                 btrfs_tree_lock(next);
6548                 btrfs_set_lock_blocking(next);
6549         }
6550
6551         level--;
6552         BUG_ON(level != btrfs_header_level(next));
6553         path->nodes[level] = next;
6554         path->slots[level] = 0;
6555         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6556         wc->level = level;
6557         if (wc->level == 1)
6558                 wc->reada_slot = 0;
6559         return 0;
6560 skip:
6561         wc->refs[level - 1] = 0;
6562         wc->flags[level - 1] = 0;
6563         if (wc->stage == DROP_REFERENCE) {
6564                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6565                         parent = path->nodes[level]->start;
6566                 } else {
6567                         BUG_ON(root->root_key.objectid !=
6568                                btrfs_header_owner(path->nodes[level]));
6569                         parent = 0;
6570                 }
6571
6572                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6573                                 root->root_key.objectid, level - 1, 0, 0);
6574                 BUG_ON(ret); /* -ENOMEM */
6575         }
6576         btrfs_tree_unlock(next);
6577         free_extent_buffer(next);
6578         *lookup_info = 1;
6579         return 1;
6580 }
6581
6582 /*
6583  * hepler to process tree block while walking up the tree.
6584  *
6585  * when wc->stage == DROP_REFERENCE, this function drops
6586  * reference count on the block.
6587  *
6588  * when wc->stage == UPDATE_BACKREF, this function changes
6589  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6590  * to UPDATE_BACKREF previously while processing the block.
6591  *
6592  * NOTE: return value 1 means we should stop walking up.
6593  */
6594 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6595                                  struct btrfs_root *root,
6596                                  struct btrfs_path *path,
6597                                  struct walk_control *wc)
6598 {
6599         int ret;
6600         int level = wc->level;
6601         struct extent_buffer *eb = path->nodes[level];
6602         u64 parent = 0;
6603
6604         if (wc->stage == UPDATE_BACKREF) {
6605                 BUG_ON(wc->shared_level < level);
6606                 if (level < wc->shared_level)
6607                         goto out;
6608
6609                 ret = find_next_key(path, level + 1, &wc->update_progress);
6610                 if (ret > 0)
6611                         wc->update_ref = 0;
6612
6613                 wc->stage = DROP_REFERENCE;
6614                 wc->shared_level = -1;
6615                 path->slots[level] = 0;
6616
6617                 /*
6618                  * check reference count again if the block isn't locked.
6619                  * we should start walking down the tree again if reference
6620                  * count is one.
6621                  */
6622                 if (!path->locks[level]) {
6623                         BUG_ON(level == 0);
6624                         btrfs_tree_lock(eb);
6625                         btrfs_set_lock_blocking(eb);
6626                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6627
6628                         ret = btrfs_lookup_extent_info(trans, root,
6629                                                        eb->start, eb->len,
6630                                                        &wc->refs[level],
6631                                                        &wc->flags[level]);
6632                         if (ret < 0) {
6633                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6634                                 return ret;
6635                         }
6636                         BUG_ON(wc->refs[level] == 0);
6637                         if (wc->refs[level] == 1) {
6638                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6639                                 return 1;
6640                         }
6641                 }
6642         }
6643
6644         /* wc->stage == DROP_REFERENCE */
6645         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6646
6647         if (wc->refs[level] == 1) {
6648                 if (level == 0) {
6649                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6650                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6651                                                     wc->for_reloc);
6652                         else
6653                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6654                                                     wc->for_reloc);
6655                         BUG_ON(ret); /* -ENOMEM */
6656                 }
6657                 /* make block locked assertion in clean_tree_block happy */
6658                 if (!path->locks[level] &&
6659                     btrfs_header_generation(eb) == trans->transid) {
6660                         btrfs_tree_lock(eb);
6661                         btrfs_set_lock_blocking(eb);
6662                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6663                 }
6664                 clean_tree_block(trans, root, eb);
6665         }
6666
6667         if (eb == root->node) {
6668                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6669                         parent = eb->start;
6670                 else
6671                         BUG_ON(root->root_key.objectid !=
6672                                btrfs_header_owner(eb));
6673         } else {
6674                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6675                         parent = path->nodes[level + 1]->start;
6676                 else
6677                         BUG_ON(root->root_key.objectid !=
6678                                btrfs_header_owner(path->nodes[level + 1]));
6679         }
6680
6681         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1, 0);
6682 out:
6683         wc->refs[level] = 0;
6684         wc->flags[level] = 0;
6685         return 0;
6686 }
6687
6688 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6689                                    struct btrfs_root *root,
6690                                    struct btrfs_path *path,
6691                                    struct walk_control *wc)
6692 {
6693         int level = wc->level;
6694         int lookup_info = 1;
6695         int ret;
6696
6697         while (level >= 0) {
6698                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6699                 if (ret > 0)
6700                         break;
6701
6702                 if (level == 0)
6703                         break;
6704
6705                 if (path->slots[level] >=
6706                     btrfs_header_nritems(path->nodes[level]))
6707                         break;
6708
6709                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6710                 if (ret > 0) {
6711                         path->slots[level]++;
6712                         continue;
6713                 } else if (ret < 0)
6714                         return ret;
6715                 level = wc->level;
6716         }
6717         return 0;
6718 }
6719
6720 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6721                                  struct btrfs_root *root,
6722                                  struct btrfs_path *path,
6723                                  struct walk_control *wc, int max_level)
6724 {
6725         int level = wc->level;
6726         int ret;
6727
6728         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6729         while (level < max_level && path->nodes[level]) {
6730                 wc->level = level;
6731                 if (path->slots[level] + 1 <
6732                     btrfs_header_nritems(path->nodes[level])) {
6733                         path->slots[level]++;
6734                         return 0;
6735                 } else {
6736                         ret = walk_up_proc(trans, root, path, wc);
6737                         if (ret > 0)
6738                                 return 0;
6739
6740                         if (path->locks[level]) {
6741                                 btrfs_tree_unlock_rw(path->nodes[level],
6742                                                      path->locks[level]);
6743                                 path->locks[level] = 0;
6744                         }
6745                         free_extent_buffer(path->nodes[level]);
6746                         path->nodes[level] = NULL;
6747                         level++;
6748                 }
6749         }
6750         return 1;
6751 }
6752
6753 /*
6754  * drop a subvolume tree.
6755  *
6756  * this function traverses the tree freeing any blocks that only
6757  * referenced by the tree.
6758  *
6759  * when a shared tree block is found. this function decreases its
6760  * reference count by one. if update_ref is true, this function
6761  * also make sure backrefs for the shared block and all lower level
6762  * blocks are properly updated.
6763  */
6764 int btrfs_drop_snapshot(struct btrfs_root *root,
6765                          struct btrfs_block_rsv *block_rsv, int update_ref,
6766                          int for_reloc)
6767 {
6768         struct btrfs_path *path;
6769         struct btrfs_trans_handle *trans;
6770         struct btrfs_root *tree_root = root->fs_info->tree_root;
6771         struct btrfs_root_item *root_item = &root->root_item;
6772         struct walk_control *wc;
6773         struct btrfs_key key;
6774         int err = 0;
6775         int ret;
6776         int level;
6777
6778         path = btrfs_alloc_path();
6779         if (!path) {
6780                 err = -ENOMEM;
6781                 goto out;
6782         }
6783
6784         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6785         if (!wc) {
6786                 btrfs_free_path(path);
6787                 err = -ENOMEM;
6788                 goto out;
6789         }
6790
6791         trans = btrfs_start_transaction(tree_root, 0);
6792         if (IS_ERR(trans)) {
6793                 err = PTR_ERR(trans);
6794                 goto out_free;
6795         }
6796
6797         if (block_rsv)
6798                 trans->block_rsv = block_rsv;
6799
6800         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6801                 level = btrfs_header_level(root->node);
6802                 path->nodes[level] = btrfs_lock_root_node(root);
6803                 btrfs_set_lock_blocking(path->nodes[level]);
6804                 path->slots[level] = 0;
6805                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6806                 memset(&wc->update_progress, 0,
6807                        sizeof(wc->update_progress));
6808         } else {
6809                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6810                 memcpy(&wc->update_progress, &key,
6811                        sizeof(wc->update_progress));
6812
6813                 level = root_item->drop_level;
6814                 BUG_ON(level == 0);
6815                 path->lowest_level = level;
6816                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6817                 path->lowest_level = 0;
6818                 if (ret < 0) {
6819                         err = ret;
6820                         goto out_end_trans;
6821                 }
6822                 WARN_ON(ret > 0);
6823
6824                 /*
6825                  * unlock our path, this is safe because only this
6826                  * function is allowed to delete this snapshot
6827                  */
6828                 btrfs_unlock_up_safe(path, 0);
6829
6830                 level = btrfs_header_level(root->node);
6831                 while (1) {
6832                         btrfs_tree_lock(path->nodes[level]);
6833                         btrfs_set_lock_blocking(path->nodes[level]);
6834
6835                         ret = btrfs_lookup_extent_info(trans, root,
6836                                                 path->nodes[level]->start,
6837                                                 path->nodes[level]->len,
6838                                                 &wc->refs[level],
6839                                                 &wc->flags[level]);
6840                         if (ret < 0) {
6841                                 err = ret;
6842                                 goto out_end_trans;
6843                         }
6844                         BUG_ON(wc->refs[level] == 0);
6845
6846                         if (level == root_item->drop_level)
6847                                 break;
6848
6849                         btrfs_tree_unlock(path->nodes[level]);
6850                         WARN_ON(wc->refs[level] != 1);
6851                         level--;
6852                 }
6853         }
6854
6855         wc->level = level;
6856         wc->shared_level = -1;
6857         wc->stage = DROP_REFERENCE;
6858         wc->update_ref = update_ref;
6859         wc->keep_locks = 0;
6860         wc->for_reloc = for_reloc;
6861         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6862
6863         while (1) {
6864                 ret = walk_down_tree(trans, root, path, wc);
6865                 if (ret < 0) {
6866                         err = ret;
6867                         break;
6868                 }
6869
6870                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6871                 if (ret < 0) {
6872                         err = ret;
6873                         break;
6874                 }
6875
6876                 if (ret > 0) {
6877                         BUG_ON(wc->stage != DROP_REFERENCE);
6878                         break;
6879                 }
6880
6881                 if (wc->stage == DROP_REFERENCE) {
6882                         level = wc->level;
6883                         btrfs_node_key(path->nodes[level],
6884                                        &root_item->drop_progress,
6885                                        path->slots[level]);
6886                         root_item->drop_level = level;
6887                 }
6888
6889                 BUG_ON(wc->level == 0);
6890                 if (btrfs_should_end_transaction(trans, tree_root)) {
6891                         ret = btrfs_update_root(trans, tree_root,
6892                                                 &root->root_key,
6893                                                 root_item);
6894                         if (ret) {
6895                                 btrfs_abort_transaction(trans, tree_root, ret);
6896                                 err = ret;
6897                                 goto out_end_trans;
6898                         }
6899
6900                         btrfs_end_transaction_throttle(trans, tree_root);
6901                         trans = btrfs_start_transaction(tree_root, 0);
6902                         if (IS_ERR(trans)) {
6903                                 err = PTR_ERR(trans);
6904                                 goto out_free;
6905                         }
6906                         if (block_rsv)
6907                                 trans->block_rsv = block_rsv;
6908                 }
6909         }
6910         btrfs_release_path(path);
6911         if (err)
6912                 goto out_end_trans;
6913
6914         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6915         if (ret) {
6916                 btrfs_abort_transaction(trans, tree_root, ret);
6917                 goto out_end_trans;
6918         }
6919
6920         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6921                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6922                                            NULL, NULL);
6923                 if (ret < 0) {
6924                         btrfs_abort_transaction(trans, tree_root, ret);
6925                         err = ret;
6926                         goto out_end_trans;
6927                 } else if (ret > 0) {
6928                         /* if we fail to delete the orphan item this time
6929                          * around, it'll get picked up the next time.
6930                          *
6931                          * The most common failure here is just -ENOENT.
6932                          */
6933                         btrfs_del_orphan_item(trans, tree_root,
6934                                               root->root_key.objectid);
6935                 }
6936         }
6937
6938         if (root->in_radix) {
6939                 btrfs_free_fs_root(tree_root->fs_info, root);
6940         } else {
6941                 free_extent_buffer(root->node);
6942                 free_extent_buffer(root->commit_root);
6943                 kfree(root);
6944         }
6945 out_end_trans:
6946         btrfs_end_transaction_throttle(trans, tree_root);
6947 out_free:
6948         kfree(wc);
6949         btrfs_free_path(path);
6950 out:
6951         if (err)
6952                 btrfs_std_error(root->fs_info, err);
6953         return err;
6954 }
6955
6956 /*
6957  * drop subtree rooted at tree block 'node'.
6958  *
6959  * NOTE: this function will unlock and release tree block 'node'
6960  * only used by relocation code
6961  */
6962 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6963                         struct btrfs_root *root,
6964                         struct extent_buffer *node,
6965                         struct extent_buffer *parent)
6966 {
6967         struct btrfs_path *path;
6968         struct walk_control *wc;
6969         int level;
6970         int parent_level;
6971         int ret = 0;
6972         int wret;
6973
6974         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6975
6976         path = btrfs_alloc_path();
6977         if (!path)
6978                 return -ENOMEM;
6979
6980         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6981         if (!wc) {
6982                 btrfs_free_path(path);
6983                 return -ENOMEM;
6984         }
6985
6986         btrfs_assert_tree_locked(parent);
6987         parent_level = btrfs_header_level(parent);
6988         extent_buffer_get(parent);
6989         path->nodes[parent_level] = parent;
6990         path->slots[parent_level] = btrfs_header_nritems(parent);
6991
6992         btrfs_assert_tree_locked(node);
6993         level = btrfs_header_level(node);
6994         path->nodes[level] = node;
6995         path->slots[level] = 0;
6996         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6997
6998         wc->refs[parent_level] = 1;
6999         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7000         wc->level = level;
7001         wc->shared_level = -1;
7002         wc->stage = DROP_REFERENCE;
7003         wc->update_ref = 0;
7004         wc->keep_locks = 1;
7005         wc->for_reloc = 1;
7006         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7007
7008         while (1) {
7009                 wret = walk_down_tree(trans, root, path, wc);
7010                 if (wret < 0) {
7011                         ret = wret;
7012                         break;
7013                 }
7014
7015                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7016                 if (wret < 0)
7017                         ret = wret;
7018                 if (wret != 0)
7019                         break;
7020         }
7021
7022         kfree(wc);
7023         btrfs_free_path(path);
7024         return ret;
7025 }
7026
7027 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7028 {
7029         u64 num_devices;
7030         u64 stripped;
7031
7032         /*
7033          * if restripe for this chunk_type is on pick target profile and
7034          * return, otherwise do the usual balance
7035          */
7036         stripped = get_restripe_target(root->fs_info, flags);
7037         if (stripped)
7038                 return extended_to_chunk(stripped);
7039
7040         /*
7041          * we add in the count of missing devices because we want
7042          * to make sure that any RAID levels on a degraded FS
7043          * continue to be honored.
7044          */
7045         num_devices = root->fs_info->fs_devices->rw_devices +
7046                 root->fs_info->fs_devices->missing_devices;
7047
7048         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7049                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7050
7051         if (num_devices == 1) {
7052                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7053                 stripped = flags & ~stripped;
7054
7055                 /* turn raid0 into single device chunks */
7056                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7057                         return stripped;
7058
7059                 /* turn mirroring into duplication */
7060                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7061                              BTRFS_BLOCK_GROUP_RAID10))
7062                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7063         } else {
7064                 /* they already had raid on here, just return */
7065                 if (flags & stripped)
7066                         return flags;
7067
7068                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7069                 stripped = flags & ~stripped;
7070
7071                 /* switch duplicated blocks with raid1 */
7072                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7073                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7074
7075                 /* this is drive concat, leave it alone */
7076         }
7077
7078         return flags;
7079 }
7080
7081 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7082 {
7083         struct btrfs_space_info *sinfo = cache->space_info;
7084         u64 num_bytes;
7085         u64 min_allocable_bytes;
7086         int ret = -ENOSPC;
7087
7088
7089         /*
7090          * We need some metadata space and system metadata space for
7091          * allocating chunks in some corner cases until we force to set
7092          * it to be readonly.
7093          */
7094         if ((sinfo->flags &
7095              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7096             !force)
7097                 min_allocable_bytes = 1 * 1024 * 1024;
7098         else
7099                 min_allocable_bytes = 0;
7100
7101         spin_lock(&sinfo->lock);
7102         spin_lock(&cache->lock);
7103
7104         if (cache->ro) {
7105                 ret = 0;
7106                 goto out;
7107         }
7108
7109         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7110                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7111
7112         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7113             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7114             min_allocable_bytes <= sinfo->total_bytes) {
7115                 sinfo->bytes_readonly += num_bytes;
7116                 cache->ro = 1;
7117                 ret = 0;
7118         }
7119 out:
7120         spin_unlock(&cache->lock);
7121         spin_unlock(&sinfo->lock);
7122         return ret;
7123 }
7124
7125 int btrfs_set_block_group_ro(struct btrfs_root *root,
7126                              struct btrfs_block_group_cache *cache)
7127
7128 {
7129         struct btrfs_trans_handle *trans;
7130         u64 alloc_flags;
7131         int ret;
7132
7133         BUG_ON(cache->ro);
7134
7135         trans = btrfs_join_transaction(root);
7136         if (IS_ERR(trans))
7137                 return PTR_ERR(trans);
7138
7139         alloc_flags = update_block_group_flags(root, cache->flags);
7140         if (alloc_flags != cache->flags) {
7141                 ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7142                                      CHUNK_ALLOC_FORCE);
7143                 if (ret < 0)
7144                         goto out;
7145         }
7146
7147         ret = set_block_group_ro(cache, 0);
7148         if (!ret)
7149                 goto out;
7150         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7151         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7152                              CHUNK_ALLOC_FORCE);
7153         if (ret < 0)
7154                 goto out;
7155         ret = set_block_group_ro(cache, 0);
7156 out:
7157         btrfs_end_transaction(trans, root);
7158         return ret;
7159 }
7160
7161 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7162                             struct btrfs_root *root, u64 type)
7163 {
7164         u64 alloc_flags = get_alloc_profile(root, type);
7165         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7166                               CHUNK_ALLOC_FORCE);
7167 }
7168
7169 /*
7170  * helper to account the unused space of all the readonly block group in the
7171  * list. takes mirrors into account.
7172  */
7173 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7174 {
7175         struct btrfs_block_group_cache *block_group;
7176         u64 free_bytes = 0;
7177         int factor;
7178
7179         list_for_each_entry(block_group, groups_list, list) {
7180                 spin_lock(&block_group->lock);
7181
7182                 if (!block_group->ro) {
7183                         spin_unlock(&block_group->lock);
7184                         continue;
7185                 }
7186
7187                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7188                                           BTRFS_BLOCK_GROUP_RAID10 |
7189                                           BTRFS_BLOCK_GROUP_DUP))
7190                         factor = 2;
7191                 else
7192                         factor = 1;
7193
7194                 free_bytes += (block_group->key.offset -
7195                                btrfs_block_group_used(&block_group->item)) *
7196                                factor;
7197
7198                 spin_unlock(&block_group->lock);
7199         }
7200
7201         return free_bytes;
7202 }
7203
7204 /*
7205  * helper to account the unused space of all the readonly block group in the
7206  * space_info. takes mirrors into account.
7207  */
7208 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7209 {
7210         int i;
7211         u64 free_bytes = 0;
7212
7213         spin_lock(&sinfo->lock);
7214
7215         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7216                 if (!list_empty(&sinfo->block_groups[i]))
7217                         free_bytes += __btrfs_get_ro_block_group_free_space(
7218                                                 &sinfo->block_groups[i]);
7219
7220         spin_unlock(&sinfo->lock);
7221
7222         return free_bytes;
7223 }
7224
7225 void btrfs_set_block_group_rw(struct btrfs_root *root,
7226                               struct btrfs_block_group_cache *cache)
7227 {
7228         struct btrfs_space_info *sinfo = cache->space_info;
7229         u64 num_bytes;
7230
7231         BUG_ON(!cache->ro);
7232
7233         spin_lock(&sinfo->lock);
7234         spin_lock(&cache->lock);
7235         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7236                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7237         sinfo->bytes_readonly -= num_bytes;
7238         cache->ro = 0;
7239         spin_unlock(&cache->lock);
7240         spin_unlock(&sinfo->lock);
7241 }
7242
7243 /*
7244  * checks to see if its even possible to relocate this block group.
7245  *
7246  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7247  * ok to go ahead and try.
7248  */
7249 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7250 {
7251         struct btrfs_block_group_cache *block_group;
7252         struct btrfs_space_info *space_info;
7253         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7254         struct btrfs_device *device;
7255         u64 min_free;
7256         u64 dev_min = 1;
7257         u64 dev_nr = 0;
7258         u64 target;
7259         int index;
7260         int full = 0;
7261         int ret = 0;
7262
7263         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7264
7265         /* odd, couldn't find the block group, leave it alone */
7266         if (!block_group)
7267                 return -1;
7268
7269         min_free = btrfs_block_group_used(&block_group->item);
7270
7271         /* no bytes used, we're good */
7272         if (!min_free)
7273                 goto out;
7274
7275         space_info = block_group->space_info;
7276         spin_lock(&space_info->lock);
7277
7278         full = space_info->full;
7279
7280         /*
7281          * if this is the last block group we have in this space, we can't
7282          * relocate it unless we're able to allocate a new chunk below.
7283          *
7284          * Otherwise, we need to make sure we have room in the space to handle
7285          * all of the extents from this block group.  If we can, we're good
7286          */
7287         if ((space_info->total_bytes != block_group->key.offset) &&
7288             (space_info->bytes_used + space_info->bytes_reserved +
7289              space_info->bytes_pinned + space_info->bytes_readonly +
7290              min_free < space_info->total_bytes)) {
7291                 spin_unlock(&space_info->lock);
7292                 goto out;
7293         }
7294         spin_unlock(&space_info->lock);
7295
7296         /*
7297          * ok we don't have enough space, but maybe we have free space on our
7298          * devices to allocate new chunks for relocation, so loop through our
7299          * alloc devices and guess if we have enough space.  if this block
7300          * group is going to be restriped, run checks against the target
7301          * profile instead of the current one.
7302          */
7303         ret = -1;
7304
7305         /*
7306          * index:
7307          *      0: raid10
7308          *      1: raid1
7309          *      2: dup
7310          *      3: raid0
7311          *      4: single
7312          */
7313         target = get_restripe_target(root->fs_info, block_group->flags);
7314         if (target) {
7315                 index = __get_block_group_index(extended_to_chunk(target));
7316         } else {
7317                 /*
7318                  * this is just a balance, so if we were marked as full
7319                  * we know there is no space for a new chunk
7320                  */
7321                 if (full)
7322                         goto out;
7323
7324                 index = get_block_group_index(block_group);
7325         }
7326
7327         if (index == 0) {
7328                 dev_min = 4;
7329                 /* Divide by 2 */
7330                 min_free >>= 1;
7331         } else if (index == 1) {
7332                 dev_min = 2;
7333         } else if (index == 2) {
7334                 /* Multiply by 2 */
7335                 min_free <<= 1;
7336         } else if (index == 3) {
7337                 dev_min = fs_devices->rw_devices;
7338                 do_div(min_free, dev_min);
7339         }
7340
7341         mutex_lock(&root->fs_info->chunk_mutex);
7342         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7343                 u64 dev_offset;
7344
7345                 /*
7346                  * check to make sure we can actually find a chunk with enough
7347                  * space to fit our block group in.
7348                  */
7349                 if (device->total_bytes > device->bytes_used + min_free) {
7350                         ret = find_free_dev_extent(device, min_free,
7351                                                    &dev_offset, NULL);
7352                         if (!ret)
7353                                 dev_nr++;
7354
7355                         if (dev_nr >= dev_min)
7356                                 break;
7357
7358                         ret = -1;
7359                 }
7360         }
7361         mutex_unlock(&root->fs_info->chunk_mutex);
7362 out:
7363         btrfs_put_block_group(block_group);
7364         return ret;
7365 }
7366
7367 static int find_first_block_group(struct btrfs_root *root,
7368                 struct btrfs_path *path, struct btrfs_key *key)
7369 {
7370         int ret = 0;
7371         struct btrfs_key found_key;
7372         struct extent_buffer *leaf;
7373         int slot;
7374
7375         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7376         if (ret < 0)
7377                 goto out;
7378
7379         while (1) {
7380                 slot = path->slots[0];
7381                 leaf = path->nodes[0];
7382                 if (slot >= btrfs_header_nritems(leaf)) {
7383                         ret = btrfs_next_leaf(root, path);
7384                         if (ret == 0)
7385                                 continue;
7386                         if (ret < 0)
7387                                 goto out;
7388                         break;
7389                 }
7390                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7391
7392                 if (found_key.objectid >= key->objectid &&
7393                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7394                         ret = 0;
7395                         goto out;
7396                 }
7397                 path->slots[0]++;
7398         }
7399 out:
7400         return ret;
7401 }
7402
7403 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7404 {
7405         struct btrfs_block_group_cache *block_group;
7406         u64 last = 0;
7407
7408         while (1) {
7409                 struct inode *inode;
7410
7411                 block_group = btrfs_lookup_first_block_group(info, last);
7412                 while (block_group) {
7413                         spin_lock(&block_group->lock);
7414                         if (block_group->iref)
7415                                 break;
7416                         spin_unlock(&block_group->lock);
7417                         block_group = next_block_group(info->tree_root,
7418                                                        block_group);
7419                 }
7420                 if (!block_group) {
7421                         if (last == 0)
7422                                 break;
7423                         last = 0;
7424                         continue;
7425                 }
7426
7427                 inode = block_group->inode;
7428                 block_group->iref = 0;
7429                 block_group->inode = NULL;
7430                 spin_unlock(&block_group->lock);
7431                 iput(inode);
7432                 last = block_group->key.objectid + block_group->key.offset;
7433                 btrfs_put_block_group(block_group);
7434         }
7435 }
7436
7437 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7438 {
7439         struct btrfs_block_group_cache *block_group;
7440         struct btrfs_space_info *space_info;
7441         struct btrfs_caching_control *caching_ctl;
7442         struct rb_node *n;
7443
7444         down_write(&info->extent_commit_sem);
7445         while (!list_empty(&info->caching_block_groups)) {
7446                 caching_ctl = list_entry(info->caching_block_groups.next,
7447                                          struct btrfs_caching_control, list);
7448                 list_del(&caching_ctl->list);
7449                 put_caching_control(caching_ctl);
7450         }
7451         up_write(&info->extent_commit_sem);
7452
7453         spin_lock(&info->block_group_cache_lock);
7454         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7455                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7456                                        cache_node);
7457                 rb_erase(&block_group->cache_node,
7458                          &info->block_group_cache_tree);
7459                 spin_unlock(&info->block_group_cache_lock);
7460
7461                 down_write(&block_group->space_info->groups_sem);
7462                 list_del(&block_group->list);
7463                 up_write(&block_group->space_info->groups_sem);
7464
7465                 if (block_group->cached == BTRFS_CACHE_STARTED)
7466                         wait_block_group_cache_done(block_group);
7467
7468                 /*
7469                  * We haven't cached this block group, which means we could
7470                  * possibly have excluded extents on this block group.
7471                  */
7472                 if (block_group->cached == BTRFS_CACHE_NO)
7473                         free_excluded_extents(info->extent_root, block_group);
7474
7475                 btrfs_remove_free_space_cache(block_group);
7476                 btrfs_put_block_group(block_group);
7477
7478                 spin_lock(&info->block_group_cache_lock);
7479         }
7480         spin_unlock(&info->block_group_cache_lock);
7481
7482         /* now that all the block groups are freed, go through and
7483          * free all the space_info structs.  This is only called during
7484          * the final stages of unmount, and so we know nobody is
7485          * using them.  We call synchronize_rcu() once before we start,
7486          * just to be on the safe side.
7487          */
7488         synchronize_rcu();
7489
7490         release_global_block_rsv(info);
7491
7492         while(!list_empty(&info->space_info)) {
7493                 space_info = list_entry(info->space_info.next,
7494                                         struct btrfs_space_info,
7495                                         list);
7496                 if (space_info->bytes_pinned > 0 ||
7497                     space_info->bytes_reserved > 0 ||
7498                     space_info->bytes_may_use > 0) {
7499                         WARN_ON(1);
7500                         dump_space_info(space_info, 0, 0);
7501                 }
7502                 list_del(&space_info->list);
7503                 kfree(space_info);
7504         }
7505         return 0;
7506 }
7507
7508 static void __link_block_group(struct btrfs_space_info *space_info,
7509                                struct btrfs_block_group_cache *cache)
7510 {
7511         int index = get_block_group_index(cache);
7512
7513         down_write(&space_info->groups_sem);
7514         list_add_tail(&cache->list, &space_info->block_groups[index]);
7515         up_write(&space_info->groups_sem);
7516 }
7517
7518 int btrfs_read_block_groups(struct btrfs_root *root)
7519 {
7520         struct btrfs_path *path;
7521         int ret;
7522         struct btrfs_block_group_cache *cache;
7523         struct btrfs_fs_info *info = root->fs_info;
7524         struct btrfs_space_info *space_info;
7525         struct btrfs_key key;
7526         struct btrfs_key found_key;
7527         struct extent_buffer *leaf;
7528         int need_clear = 0;
7529         u64 cache_gen;
7530
7531         root = info->extent_root;
7532         key.objectid = 0;
7533         key.offset = 0;
7534         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7535         path = btrfs_alloc_path();
7536         if (!path)
7537                 return -ENOMEM;
7538         path->reada = 1;
7539
7540         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7541         if (btrfs_test_opt(root, SPACE_CACHE) &&
7542             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7543                 need_clear = 1;
7544         if (btrfs_test_opt(root, CLEAR_CACHE))
7545                 need_clear = 1;
7546
7547         while (1) {
7548                 ret = find_first_block_group(root, path, &key);
7549                 if (ret > 0)
7550                         break;
7551                 if (ret != 0)
7552                         goto error;
7553                 leaf = path->nodes[0];
7554                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7555                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7556                 if (!cache) {
7557                         ret = -ENOMEM;
7558                         goto error;
7559                 }
7560                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7561                                                 GFP_NOFS);
7562                 if (!cache->free_space_ctl) {
7563                         kfree(cache);
7564                         ret = -ENOMEM;
7565                         goto error;
7566                 }
7567
7568                 atomic_set(&cache->count, 1);
7569                 spin_lock_init(&cache->lock);
7570                 cache->fs_info = info;
7571                 INIT_LIST_HEAD(&cache->list);
7572                 INIT_LIST_HEAD(&cache->cluster_list);
7573
7574                 if (need_clear)
7575                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7576
7577                 read_extent_buffer(leaf, &cache->item,
7578                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7579                                    sizeof(cache->item));
7580                 memcpy(&cache->key, &found_key, sizeof(found_key));
7581
7582                 key.objectid = found_key.objectid + found_key.offset;
7583                 btrfs_release_path(path);
7584                 cache->flags = btrfs_block_group_flags(&cache->item);
7585                 cache->sectorsize = root->sectorsize;
7586
7587                 btrfs_init_free_space_ctl(cache);
7588
7589                 /*
7590                  * We need to exclude the super stripes now so that the space
7591                  * info has super bytes accounted for, otherwise we'll think
7592                  * we have more space than we actually do.
7593                  */
7594                 exclude_super_stripes(root, cache);
7595
7596                 /*
7597                  * check for two cases, either we are full, and therefore
7598                  * don't need to bother with the caching work since we won't
7599                  * find any space, or we are empty, and we can just add all
7600                  * the space in and be done with it.  This saves us _alot_ of
7601                  * time, particularly in the full case.
7602                  */
7603                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7604                         cache->last_byte_to_unpin = (u64)-1;
7605                         cache->cached = BTRFS_CACHE_FINISHED;
7606                         free_excluded_extents(root, cache);
7607                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7608                         cache->last_byte_to_unpin = (u64)-1;
7609                         cache->cached = BTRFS_CACHE_FINISHED;
7610                         add_new_free_space(cache, root->fs_info,
7611                                            found_key.objectid,
7612                                            found_key.objectid +
7613                                            found_key.offset);
7614                         free_excluded_extents(root, cache);
7615                 }
7616
7617                 ret = update_space_info(info, cache->flags, found_key.offset,
7618                                         btrfs_block_group_used(&cache->item),
7619                                         &space_info);
7620                 BUG_ON(ret); /* -ENOMEM */
7621                 cache->space_info = space_info;
7622                 spin_lock(&cache->space_info->lock);
7623                 cache->space_info->bytes_readonly += cache->bytes_super;
7624                 spin_unlock(&cache->space_info->lock);
7625
7626                 __link_block_group(space_info, cache);
7627
7628                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7629                 BUG_ON(ret); /* Logic error */
7630
7631                 set_avail_alloc_bits(root->fs_info, cache->flags);
7632                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7633                         set_block_group_ro(cache, 1);
7634         }
7635
7636         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7637                 if (!(get_alloc_profile(root, space_info->flags) &
7638                       (BTRFS_BLOCK_GROUP_RAID10 |
7639                        BTRFS_BLOCK_GROUP_RAID1 |
7640                        BTRFS_BLOCK_GROUP_DUP)))
7641                         continue;
7642                 /*
7643                  * avoid allocating from un-mirrored block group if there are
7644                  * mirrored block groups.
7645                  */
7646                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7647                         set_block_group_ro(cache, 1);
7648                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7649                         set_block_group_ro(cache, 1);
7650         }
7651
7652         init_global_block_rsv(info);
7653         ret = 0;
7654 error:
7655         btrfs_free_path(path);
7656         return ret;
7657 }
7658
7659 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7660                            struct btrfs_root *root, u64 bytes_used,
7661                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7662                            u64 size)
7663 {
7664         int ret;
7665         struct btrfs_root *extent_root;
7666         struct btrfs_block_group_cache *cache;
7667
7668         extent_root = root->fs_info->extent_root;
7669
7670         root->fs_info->last_trans_log_full_commit = trans->transid;
7671
7672         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7673         if (!cache)
7674                 return -ENOMEM;
7675         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7676                                         GFP_NOFS);
7677         if (!cache->free_space_ctl) {
7678                 kfree(cache);
7679                 return -ENOMEM;
7680         }
7681
7682         cache->key.objectid = chunk_offset;
7683         cache->key.offset = size;
7684         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7685         cache->sectorsize = root->sectorsize;
7686         cache->fs_info = root->fs_info;
7687
7688         atomic_set(&cache->count, 1);
7689         spin_lock_init(&cache->lock);
7690         INIT_LIST_HEAD(&cache->list);
7691         INIT_LIST_HEAD(&cache->cluster_list);
7692
7693         btrfs_init_free_space_ctl(cache);
7694
7695         btrfs_set_block_group_used(&cache->item, bytes_used);
7696         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7697         cache->flags = type;
7698         btrfs_set_block_group_flags(&cache->item, type);
7699
7700         cache->last_byte_to_unpin = (u64)-1;
7701         cache->cached = BTRFS_CACHE_FINISHED;
7702         exclude_super_stripes(root, cache);
7703
7704         add_new_free_space(cache, root->fs_info, chunk_offset,
7705                            chunk_offset + size);
7706
7707         free_excluded_extents(root, cache);
7708
7709         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7710                                 &cache->space_info);
7711         BUG_ON(ret); /* -ENOMEM */
7712         update_global_block_rsv(root->fs_info);
7713
7714         spin_lock(&cache->space_info->lock);
7715         cache->space_info->bytes_readonly += cache->bytes_super;
7716         spin_unlock(&cache->space_info->lock);
7717
7718         __link_block_group(cache->space_info, cache);
7719
7720         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7721         BUG_ON(ret); /* Logic error */
7722
7723         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7724                                 sizeof(cache->item));
7725         if (ret) {
7726                 btrfs_abort_transaction(trans, extent_root, ret);
7727                 return ret;
7728         }
7729
7730         set_avail_alloc_bits(extent_root->fs_info, type);
7731
7732         return 0;
7733 }
7734
7735 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7736 {
7737         u64 extra_flags = chunk_to_extended(flags) &
7738                                 BTRFS_EXTENDED_PROFILE_MASK;
7739
7740         if (flags & BTRFS_BLOCK_GROUP_DATA)
7741                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7742         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7743                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7744         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7745                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7746 }
7747
7748 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7749                              struct btrfs_root *root, u64 group_start)
7750 {
7751         struct btrfs_path *path;
7752         struct btrfs_block_group_cache *block_group;
7753         struct btrfs_free_cluster *cluster;
7754         struct btrfs_root *tree_root = root->fs_info->tree_root;
7755         struct btrfs_key key;
7756         struct inode *inode;
7757         int ret;
7758         int index;
7759         int factor;
7760
7761         root = root->fs_info->extent_root;
7762
7763         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7764         BUG_ON(!block_group);
7765         BUG_ON(!block_group->ro);
7766
7767         /*
7768          * Free the reserved super bytes from this block group before
7769          * remove it.
7770          */
7771         free_excluded_extents(root, block_group);
7772
7773         memcpy(&key, &block_group->key, sizeof(key));
7774         index = get_block_group_index(block_group);
7775         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7776                                   BTRFS_BLOCK_GROUP_RAID1 |
7777                                   BTRFS_BLOCK_GROUP_RAID10))
7778                 factor = 2;
7779         else
7780                 factor = 1;
7781
7782         /* make sure this block group isn't part of an allocation cluster */
7783         cluster = &root->fs_info->data_alloc_cluster;
7784         spin_lock(&cluster->refill_lock);
7785         btrfs_return_cluster_to_free_space(block_group, cluster);
7786         spin_unlock(&cluster->refill_lock);
7787
7788         /*
7789          * make sure this block group isn't part of a metadata
7790          * allocation cluster
7791          */
7792         cluster = &root->fs_info->meta_alloc_cluster;
7793         spin_lock(&cluster->refill_lock);
7794         btrfs_return_cluster_to_free_space(block_group, cluster);
7795         spin_unlock(&cluster->refill_lock);
7796
7797         path = btrfs_alloc_path();
7798         if (!path) {
7799                 ret = -ENOMEM;
7800                 goto out;
7801         }
7802
7803         inode = lookup_free_space_inode(tree_root, block_group, path);
7804         if (!IS_ERR(inode)) {
7805                 ret = btrfs_orphan_add(trans, inode);
7806                 if (ret) {
7807                         btrfs_add_delayed_iput(inode);
7808                         goto out;
7809                 }
7810                 clear_nlink(inode);
7811                 /* One for the block groups ref */
7812                 spin_lock(&block_group->lock);
7813                 if (block_group->iref) {
7814                         block_group->iref = 0;
7815                         block_group->inode = NULL;
7816                         spin_unlock(&block_group->lock);
7817                         iput(inode);
7818                 } else {
7819                         spin_unlock(&block_group->lock);
7820                 }
7821                 /* One for our lookup ref */
7822                 btrfs_add_delayed_iput(inode);
7823         }
7824
7825         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7826         key.offset = block_group->key.objectid;
7827         key.type = 0;
7828
7829         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7830         if (ret < 0)
7831                 goto out;
7832         if (ret > 0)
7833                 btrfs_release_path(path);
7834         if (ret == 0) {
7835                 ret = btrfs_del_item(trans, tree_root, path);
7836                 if (ret)
7837                         goto out;
7838                 btrfs_release_path(path);
7839         }
7840
7841         spin_lock(&root->fs_info->block_group_cache_lock);
7842         rb_erase(&block_group->cache_node,
7843                  &root->fs_info->block_group_cache_tree);
7844         spin_unlock(&root->fs_info->block_group_cache_lock);
7845
7846         down_write(&block_group->space_info->groups_sem);
7847         /*
7848          * we must use list_del_init so people can check to see if they
7849          * are still on the list after taking the semaphore
7850          */
7851         list_del_init(&block_group->list);
7852         if (list_empty(&block_group->space_info->block_groups[index]))
7853                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7854         up_write(&block_group->space_info->groups_sem);
7855
7856         if (block_group->cached == BTRFS_CACHE_STARTED)
7857                 wait_block_group_cache_done(block_group);
7858
7859         btrfs_remove_free_space_cache(block_group);
7860
7861         spin_lock(&block_group->space_info->lock);
7862         block_group->space_info->total_bytes -= block_group->key.offset;
7863         block_group->space_info->bytes_readonly -= block_group->key.offset;
7864         block_group->space_info->disk_total -= block_group->key.offset * factor;
7865         spin_unlock(&block_group->space_info->lock);
7866
7867         memcpy(&key, &block_group->key, sizeof(key));
7868
7869         btrfs_clear_space_info_full(root->fs_info);
7870
7871         btrfs_put_block_group(block_group);
7872         btrfs_put_block_group(block_group);
7873
7874         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7875         if (ret > 0)
7876                 ret = -EIO;
7877         if (ret < 0)
7878                 goto out;
7879
7880         ret = btrfs_del_item(trans, root, path);
7881 out:
7882         btrfs_free_path(path);
7883         return ret;
7884 }
7885
7886 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7887 {
7888         struct btrfs_space_info *space_info;
7889         struct btrfs_super_block *disk_super;
7890         u64 features;
7891         u64 flags;
7892         int mixed = 0;
7893         int ret;
7894
7895         disk_super = fs_info->super_copy;
7896         if (!btrfs_super_root(disk_super))
7897                 return 1;
7898
7899         features = btrfs_super_incompat_flags(disk_super);
7900         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7901                 mixed = 1;
7902
7903         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7904         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7905         if (ret)
7906                 goto out;
7907
7908         if (mixed) {
7909                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7910                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7911         } else {
7912                 flags = BTRFS_BLOCK_GROUP_METADATA;
7913                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7914                 if (ret)
7915                         goto out;
7916
7917                 flags = BTRFS_BLOCK_GROUP_DATA;
7918                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7919         }
7920 out:
7921         return ret;
7922 }
7923
7924 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7925 {
7926         return unpin_extent_range(root, start, end);
7927 }
7928
7929 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7930                                u64 num_bytes, u64 *actual_bytes)
7931 {
7932         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7933 }
7934
7935 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7936 {
7937         struct btrfs_fs_info *fs_info = root->fs_info;
7938         struct btrfs_block_group_cache *cache = NULL;
7939         u64 group_trimmed;
7940         u64 start;
7941         u64 end;
7942         u64 trimmed = 0;
7943         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
7944         int ret = 0;
7945
7946         /*
7947          * try to trim all FS space, our block group may start from non-zero.
7948          */
7949         if (range->len == total_bytes)
7950                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
7951         else
7952                 cache = btrfs_lookup_block_group(fs_info, range->start);
7953
7954         while (cache) {
7955                 if (cache->key.objectid >= (range->start + range->len)) {
7956                         btrfs_put_block_group(cache);
7957                         break;
7958                 }
7959
7960                 start = max(range->start, cache->key.objectid);
7961                 end = min(range->start + range->len,
7962                                 cache->key.objectid + cache->key.offset);
7963
7964                 if (end - start >= range->minlen) {
7965                         if (!block_group_cache_done(cache)) {
7966                                 ret = cache_block_group(cache, NULL, root, 0);
7967                                 if (!ret)
7968                                         wait_block_group_cache_done(cache);
7969                         }
7970                         ret = btrfs_trim_block_group(cache,
7971                                                      &group_trimmed,
7972                                                      start,
7973                                                      end,
7974                                                      range->minlen);
7975
7976                         trimmed += group_trimmed;
7977                         if (ret) {
7978                                 btrfs_put_block_group(cache);
7979                                 break;
7980                         }
7981                 }
7982
7983                 cache = next_block_group(fs_info->tree_root, cache);
7984         }
7985
7986         range->len = trimmed;
7987         return ret;
7988 }