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 "compat.h"
  27 #include "hash.h"
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "print-tree.h"
  31 #include "transaction.h"
  32 #include "volumes.h"
  33 #include "locking.h"
  34 #include "free-space-cache.h"
  35
  36 /* control flags for do_chunk_alloc's force field
  37  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  38  * if we really need one.
  39  *
  40  * CHUNK_ALLOC_FORCE means it must try to allocate 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  */
  49 enum {
  50         CHUNK_ALLOC_NO_FORCE = 0,
  51         CHUNK_ALLOC_FORCE = 1,
  52         CHUNK_ALLOC_LIMITED = 2,
  53 };
  54
  55 static int update_block_group(struct btrfs_trans_handle *trans,
  56                               struct btrfs_root *root,
  57                               u64 bytenr, u64 num_bytes, int alloc);
  58 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  59                                 struct btrfs_root *root,
  60                                 u64 bytenr, u64 num_bytes, u64 parent,
  61                                 u64 root_objectid, u64 owner_objectid,
  62                                 u64 owner_offset, int refs_to_drop,
  63                                 struct btrfs_delayed_extent_op *extra_op);
  64 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  65                                     struct extent_buffer *leaf,
  66                                     struct btrfs_extent_item *ei);
  67 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  68                                       struct btrfs_root *root,
  69                                       u64 parent, u64 root_objectid,
  70                                       u64 flags, u64 owner, u64 offset,
  71                                       struct btrfs_key *ins, int ref_mod);
  72 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  73                                      struct btrfs_root *root,
  74                                      u64 parent, u64 root_objectid,
  75                                      u64 flags, struct btrfs_disk_key *key,
  76                                      int level, struct btrfs_key *ins);
  77 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  78                           struct btrfs_root *extent_root, u64 alloc_bytes,
  79                           u64 flags, int force);
  80 static int find_next_key(struct btrfs_path *path, int level,
  81                          struct btrfs_key *key);
  82 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  83                             int dump_block_groups);
  84
  85 static noinline int
  86 block_group_cache_done(struct btrfs_block_group_cache *cache)
  87 {
  88         smp_mb();
  89         return cache->cached == BTRFS_CACHE_FINISHED;
  90 }
  91
  92 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  93 {
  94         return (cache->flags & bits) == bits;
  95 }
  96
  97 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  98 {
  99         atomic_inc(&cache->count);
 100 }
 101
 102 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 103 {
 104         if (atomic_dec_and_test(&cache->count)) {
 105                 WARN_ON(cache->pinned > 0);
 106                 WARN_ON(cache->reserved > 0);
 107                 WARN_ON(cache->reserved_pinned > 0);
 108                 kfree(cache->free_space_ctl);
 109                 kfree(cache);
 110         }
 111 }
 112
 113 /*
 114  * this adds the block group to the fs_info rb tree for the block group
 115  * cache
 116  */
 117 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 118                                 struct btrfs_block_group_cache *block_group)
 119 {
 120         struct rb_node **p;
 121         struct rb_node *parent = NULL;
 122         struct btrfs_block_group_cache *cache;
 123
 124         spin_lock(&info->block_group_cache_lock);
 125         p = &info->block_group_cache_tree.rb_node;
 126
 127         while (*p) {
 128                 parent = *p;
 129                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 130                                  cache_node);
 131                 if (block_group->key.objectid < cache->key.objectid) {
 132                         p = &(*p)->rb_left;
 133                 } else if (block_group->key.objectid > cache->key.objectid) {
 134                         p = &(*p)->rb_right;
 135                 } else {
 136                         spin_unlock(&info->block_group_cache_lock);
 137                         return -EEXIST;
 138                 }
 139         }
 140
 141         rb_link_node(&block_group->cache_node, parent, p);
 142         rb_insert_color(&block_group->cache_node,
 143                         &info->block_group_cache_tree);
 144         spin_unlock(&info->block_group_cache_lock);
 145
 146         return 0;
 147 }
 148
 149 /*
 150  * This will return the block group at or after bytenr if contains is 0, else
 151  * it will return the block group that contains the bytenr
 152  */
 153 static struct btrfs_block_group_cache *
 154 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 155                               int contains)
 156 {
 157         struct btrfs_block_group_cache *cache, *ret = NULL;
 158         struct rb_node *n;
 159         u64 end, start;
 160
 161         spin_lock(&info->block_group_cache_lock);
 162         n = info->block_group_cache_tree.rb_node;
 163
 164         while (n) {
 165                 cache = rb_entry(n, struct btrfs_block_group_cache,
 166                                  cache_node);
 167                 end = cache->key.objectid + cache->key.offset - 1;
 168                 start = cache->key.objectid;
 169
 170                 if (bytenr < start) {
 171                         if (!contains && (!ret || start < ret->key.objectid))
 172                                 ret = cache;
 173                         n = n->rb_left;
 174                 } else if (bytenr > start) {
 175                         if (contains && bytenr <= end) {
 176                                 ret = cache;
 177                                 break;
 178                         }
 179                         n = n->rb_right;
 180                 } else {
 181                         ret = cache;
 182                         break;
 183                 }
 184         }
 185         if (ret)
 186                 btrfs_get_block_group(ret);
 187         spin_unlock(&info->block_group_cache_lock);
 188
 189         return ret;
 190 }
 191
 192 static int add_excluded_extent(struct btrfs_root *root,
 193                                u64 start, u64 num_bytes)
 194 {
 195         u64 end = start + num_bytes - 1;
 196         set_extent_bits(&root->fs_info->freed_extents[0],
 197                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 198         set_extent_bits(&root->fs_info->freed_extents[1],
 199                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 200         return 0;
 201 }
 202
 203 static void free_excluded_extents(struct btrfs_root *root,
 204                                   struct btrfs_block_group_cache *cache)
 205 {
 206         u64 start, end;
 207
 208         start = cache->key.objectid;
 209         end = start + cache->key.offset - 1;
 210
 211         clear_extent_bits(&root->fs_info->freed_extents[0],
 212                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 213         clear_extent_bits(&root->fs_info->freed_extents[1],
 214                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 215 }
 216
 217 static int exclude_super_stripes(struct btrfs_root *root,
 218                                  struct btrfs_block_group_cache *cache)
 219 {
 220         u64 bytenr;
 221         u64 *logical;
 222         int stripe_len;
 223         int i, nr, ret;
 224
 225         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 226                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 227                 cache->bytes_super += stripe_len;
 228                 ret = add_excluded_extent(root, cache->key.objectid,
 229                                           stripe_len);
 230                 BUG_ON(ret);
 231         }
 232
 233         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 234                 bytenr = btrfs_sb_offset(i);
 235                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 236                                        cache->key.objectid, bytenr,
 237                                        0, &logical, &nr, &stripe_len);
 238                 BUG_ON(ret);
 239
 240                 while (nr--) {
 241                         cache->bytes_super += stripe_len;
 242                         ret = add_excluded_extent(root, logical[nr],
 243                                                   stripe_len);
 244                         BUG_ON(ret);
 245                 }
 246
 247                 kfree(logical);
 248         }
 249         return 0;
 250 }
 251
 252 static struct btrfs_caching_control *
 253 get_caching_control(struct btrfs_block_group_cache *cache)
 254 {
 255         struct btrfs_caching_control *ctl;
 256
 257         spin_lock(&cache->lock);
 258         if (cache->cached != BTRFS_CACHE_STARTED) {
 259                 spin_unlock(&cache->lock);
 260                 return NULL;
 261         }
 262
 263         /* We're loading it the fast way, so we don't have a caching_ctl. */
 264         if (!cache->caching_ctl) {
 265                 spin_unlock(&cache->lock);
 266                 return NULL;
 267         }
 268
 269         ctl = cache->caching_ctl;
 270         atomic_inc(&ctl->count);
 271         spin_unlock(&cache->lock);
 272         return ctl;
 273 }
 274
 275 static void put_caching_control(struct btrfs_caching_control *ctl)
 276 {
 277         if (atomic_dec_and_test(&ctl->count))
 278                 kfree(ctl);
 279 }
 280
 281 /*
 282  * this is only called by cache_block_group, since we could have freed extents
 283  * we need to check the pinned_extents for any extents that can't be used yet
 284  * since their free space will be released as soon as the transaction commits.
 285  */
 286 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 287                               struct btrfs_fs_info *info, u64 start, u64 end)
 288 {
 289         u64 extent_start, extent_end, size, total_added = 0;
 290         int ret;
 291
 292         while (start < end) {
 293                 ret = find_first_extent_bit(info->pinned_extents, start,
 294                                             &extent_start, &extent_end,
 295                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 296                 if (ret)
 297                         break;
 298
 299                 if (extent_start <= start) {
 300                         start = extent_end + 1;
 301                 } else if (extent_start > start && extent_start < end) {
 302                         size = extent_start - start;
 303                         total_added += size;
 304                         ret = btrfs_add_free_space(block_group, start,
 305                                                    size);
 306                         BUG_ON(ret);
 307                         start = extent_end + 1;
 308                 } else {
 309                         break;
 310                 }
 311         }
 312
 313         if (start < end) {
 314                 size = end - start;
 315                 total_added += size;
 316                 ret = btrfs_add_free_space(block_group, start, size);
 317                 BUG_ON(ret);
 318         }
 319
 320         return total_added;
 321 }
 322
 323 static noinline void caching_thread(struct btrfs_work *work)
 324 {
 325         struct btrfs_block_group_cache *block_group;
 326         struct btrfs_fs_info *fs_info;
 327         struct btrfs_caching_control *caching_ctl;
 328         struct btrfs_root *extent_root;
 329         struct btrfs_path *path;
 330         struct extent_buffer *leaf;
 331         struct btrfs_key key;
 332         u64 total_found = 0;
 333         u64 last = 0;
 334         u32 nritems;
 335         int ret = 0;
 336
 337         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 338         block_group = caching_ctl->block_group;
 339         fs_info = block_group->fs_info;
 340         extent_root = fs_info->extent_root;
 341
 342         path = btrfs_alloc_path();
 343         if (!path)
 344                 goto out;
 345
 346         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 347
 348         /*
 349          * We don't want to deadlock with somebody trying to allocate a new
 350          * extent for the extent root while also trying to search the extent
 351          * root to add free space.  So we skip locking and search the commit
 352          * root, since its read-only
 353          */
 354         path->skip_locking = 1;
 355         path->search_commit_root = 1;
 356         path->reada = 1;
 357
 358         key.objectid = last;
 359         key.offset = 0;
 360         key.type = BTRFS_EXTENT_ITEM_KEY;
 361 again:
 362         mutex_lock(&caching_ctl->mutex);
 363         /* need to make sure the commit_root doesn't disappear */
 364         down_read(&fs_info->extent_commit_sem);
 365
 366         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 367         if (ret < 0)
 368                 goto err;
 369
 370         leaf = path->nodes[0];
 371         nritems = btrfs_header_nritems(leaf);
 372
 373         while (1) {
 374                 if (btrfs_fs_closing(fs_info) > 1) {
 375                         last = (u64)-1;
 376                         break;
 377                 }
 378
 379                 if (path->slots[0] < nritems) {
 380                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 381                 } else {
 382                         ret = find_next_key(path, 0, &key);
 383                         if (ret)
 384                                 break;
 385
 386                         if (need_resched() ||
 387                             btrfs_next_leaf(extent_root, path)) {
 388                                 caching_ctl->progress = last;
 389                                 btrfs_release_path(path);
 390                                 up_read(&fs_info->extent_commit_sem);
 391                                 mutex_unlock(&caching_ctl->mutex);
 392                                 cond_resched();
 393                                 goto again;
 394                         }
 395                         leaf = path->nodes[0];
 396                         nritems = btrfs_header_nritems(leaf);
 397                         continue;
 398                 }
 399
 400                 if (key.objectid < block_group->key.objectid) {
 401                         path->slots[0]++;
 402                         continue;
 403                 }
 404
 405                 if (key.objectid >= block_group->key.objectid +
 406                     block_group->key.offset)
 407                         break;
 408
 409                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 410                         total_found += add_new_free_space(block_group,
 411                                                           fs_info, last,
 412                                                           key.objectid);
 413                         last = key.objectid + key.offset;
 414
 415                         if (total_found > (1024 * 1024 * 2)) {
 416                                 total_found = 0;
 417                                 wake_up(&caching_ctl->wait);
 418                         }
 419                 }
 420                 path->slots[0]++;
 421         }
 422         ret = 0;
 423
 424         total_found += add_new_free_space(block_group, fs_info, last,
 425                                           block_group->key.objectid +
 426                                           block_group->key.offset);
 427         caching_ctl->progress = (u64)-1;
 428
 429         spin_lock(&block_group->lock);
 430         block_group->caching_ctl = NULL;
 431         block_group->cached = BTRFS_CACHE_FINISHED;
 432         spin_unlock(&block_group->lock);
 433
 434 err:
 435         btrfs_free_path(path);
 436         up_read(&fs_info->extent_commit_sem);
 437
 438         free_excluded_extents(extent_root, block_group);
 439
 440         mutex_unlock(&caching_ctl->mutex);
 441 out:
 442         wake_up(&caching_ctl->wait);
 443
 444         put_caching_control(caching_ctl);
 445         btrfs_put_block_group(block_group);
 446 }
 447
 448 static int cache_block_group(struct btrfs_block_group_cache *cache,
 449                              struct btrfs_trans_handle *trans,
 450                              struct btrfs_root *root,
 451                              int load_cache_only)
 452 {
 453         struct btrfs_fs_info *fs_info = cache->fs_info;
 454         struct btrfs_caching_control *caching_ctl;
 455         int ret = 0;
 456
 457         smp_mb();
 458         if (cache->cached != BTRFS_CACHE_NO)
 459                 return 0;
 460
 461         /*
 462          * We can't do the read from on-disk cache during a commit since we need
 463          * to have the normal tree locking.  Also if we are currently trying to
 464          * allocate blocks for the tree root we can't do the fast caching since
 465          * we likely hold important locks.
 466          */
 467         if (trans && (!trans->transaction->in_commit) &&
 468             (root && root != root->fs_info->tree_root)) {
 469                 spin_lock(&cache->lock);
 470                 if (cache->cached != BTRFS_CACHE_NO) {
 471                         spin_unlock(&cache->lock);
 472                         return 0;
 473                 }
 474                 cache->cached = BTRFS_CACHE_STARTED;
 475                 spin_unlock(&cache->lock);
 476
 477                 ret = load_free_space_cache(fs_info, cache);
 478
 479                 spin_lock(&cache->lock);
 480                 if (ret == 1) {
 481                         cache->cached = BTRFS_CACHE_FINISHED;
 482                         cache->last_byte_to_unpin = (u64)-1;
 483                 } else {
 484                         cache->cached = BTRFS_CACHE_NO;
 485                 }
 486                 spin_unlock(&cache->lock);
 487                 if (ret == 1) {
 488                         free_excluded_extents(fs_info->extent_root, cache);
 489                         return 0;
 490                 }
 491         }
 492
 493         if (load_cache_only)
 494                 return 0;
 495
 496         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 497         BUG_ON(!caching_ctl);
 498
 499         INIT_LIST_HEAD(&caching_ctl->list);
 500         mutex_init(&caching_ctl->mutex);
 501         init_waitqueue_head(&caching_ctl->wait);
 502         caching_ctl->block_group = cache;
 503         caching_ctl->progress = cache->key.objectid;
 504         /* one for caching kthread, one for caching block group list */
 505         atomic_set(&caching_ctl->count, 2);
 506         caching_ctl->work.func = caching_thread;
 507
 508         spin_lock(&cache->lock);
 509         if (cache->cached != BTRFS_CACHE_NO) {
 510                 spin_unlock(&cache->lock);
 511                 kfree(caching_ctl);
 512                 return 0;
 513         }
 514         cache->caching_ctl = caching_ctl;
 515         cache->cached = BTRFS_CACHE_STARTED;
 516         spin_unlock(&cache->lock);
 517
 518         down_write(&fs_info->extent_commit_sem);
 519         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 520         up_write(&fs_info->extent_commit_sem);
 521
 522         btrfs_get_block_group(cache);
 523
 524         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 525
 526         return ret;
 527 }
 528
 529 /*
 530  * return the block group that starts at or after bytenr
 531  */
 532 static struct btrfs_block_group_cache *
 533 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 534 {
 535         struct btrfs_block_group_cache *cache;
 536
 537         cache = block_group_cache_tree_search(info, bytenr, 0);
 538
 539         return cache;
 540 }
 541
 542 /*
 543  * return the block group that contains the given bytenr
 544  */
 545 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 546                                                  struct btrfs_fs_info *info,
 547                                                  u64 bytenr)
 548 {
 549         struct btrfs_block_group_cache *cache;
 550
 551         cache = block_group_cache_tree_search(info, bytenr, 1);
 552
 553         return cache;
 554 }
 555
 556 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 557                                                   u64 flags)
 558 {
 559         struct list_head *head = &info->space_info;
 560         struct btrfs_space_info *found;
 561
 562         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
 563                  BTRFS_BLOCK_GROUP_METADATA;
 564
 565         rcu_read_lock();
 566         list_for_each_entry_rcu(found, head, list) {
 567                 if (found->flags & flags) {
 568                         rcu_read_unlock();
 569                         return found;
 570                 }
 571         }
 572         rcu_read_unlock();
 573         return NULL;
 574 }
 575
 576 /*
 577  * after adding space to the filesystem, we need to clear the full flags
 578  * on all the space infos.
 579  */
 580 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 581 {
 582         struct list_head *head = &info->space_info;
 583         struct btrfs_space_info *found;
 584
 585         rcu_read_lock();
 586         list_for_each_entry_rcu(found, head, list)
 587                 found->full = 0;
 588         rcu_read_unlock();
 589 }
 590
 591 static u64 div_factor(u64 num, int factor)
 592 {
 593         if (factor == 10)
 594                 return num;
 595         num *= factor;
 596         do_div(num, 10);
 597         return num;
 598 }
 599
 600 static u64 div_factor_fine(u64 num, int factor)
 601 {
 602         if (factor == 100)
 603                 return num;
 604         num *= factor;
 605         do_div(num, 100);
 606         return num;
 607 }
 608
 609 u64 btrfs_find_block_group(struct btrfs_root *root,
 610                            u64 search_start, u64 search_hint, int owner)
 611 {
 612         struct btrfs_block_group_cache *cache;
 613         u64 used;
 614         u64 last = max(search_hint, search_start);
 615         u64 group_start = 0;
 616         int full_search = 0;
 617         int factor = 9;
 618         int wrapped = 0;
 619 again:
 620         while (1) {
 621                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 622                 if (!cache)
 623                         break;
 624
 625                 spin_lock(&cache->lock);
 626                 last = cache->key.objectid + cache->key.offset;
 627                 used = btrfs_block_group_used(&cache->item);
 628
 629                 if ((full_search || !cache->ro) &&
 630                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 631                         if (used + cache->pinned + cache->reserved <
 632                             div_factor(cache->key.offset, factor)) {
 633                                 group_start = cache->key.objectid;
 634                                 spin_unlock(&cache->lock);
 635                                 btrfs_put_block_group(cache);
 636                                 goto found;
 637                         }
 638                 }
 639                 spin_unlock(&cache->lock);
 640                 btrfs_put_block_group(cache);
 641                 cond_resched();
 642         }
 643         if (!wrapped) {
 644                 last = search_start;
 645                 wrapped = 1;
 646                 goto again;
 647         }
 648         if (!full_search && factor < 10) {
 649                 last = search_start;
 650                 full_search = 1;
 651                 factor = 10;
 652                 goto again;
 653         }
 654 found:
 655         return group_start;
 656 }
 657
 658 /* simple helper to search for an existing extent at a given offset */
 659 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 660 {
 661         int ret;
 662         struct btrfs_key key;
 663         struct btrfs_path *path;
 664
 665         path = btrfs_alloc_path();
 666         if (!path)
 667                 return -ENOMEM;
 668
 669         key.objectid = start;
 670         key.offset = len;
 671         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 672         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 673                                 0, 0);
 674         btrfs_free_path(path);
 675         return ret;
 676 }
 677
 678 /*
 679  * helper function to lookup reference count and flags of extent.
 680  *
 681  * the head node for delayed ref is used to store the sum of all the
 682  * reference count modifications queued up in the rbtree. the head
 683  * node may also store the extent flags to set. This way you can check
 684  * to see what the reference count and extent flags would be if all of
 685  * the delayed refs are not processed.
 686  */
 687 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 688                              struct btrfs_root *root, u64 bytenr,
 689                              u64 num_bytes, u64 *refs, u64 *flags)
 690 {
 691         struct btrfs_delayed_ref_head *head;
 692         struct btrfs_delayed_ref_root *delayed_refs;
 693         struct btrfs_path *path;
 694         struct btrfs_extent_item *ei;
 695         struct extent_buffer *leaf;
 696         struct btrfs_key key;
 697         u32 item_size;
 698         u64 num_refs;
 699         u64 extent_flags;
 700         int ret;
 701
 702         path = btrfs_alloc_path();
 703         if (!path)
 704                 return -ENOMEM;
 705
 706         key.objectid = bytenr;
 707         key.type = BTRFS_EXTENT_ITEM_KEY;
 708         key.offset = num_bytes;
 709         if (!trans) {
 710                 path->skip_locking = 1;
 711                 path->search_commit_root = 1;
 712         }
 713 again:
 714         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 715                                 &key, path, 0, 0);
 716         if (ret < 0)
 717                 goto out_free;
 718
 719         if (ret == 0) {
 720                 leaf = path->nodes[0];
 721                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 722                 if (item_size >= sizeof(*ei)) {
 723                         ei = btrfs_item_ptr(leaf, path->slots[0],
 724                                             struct btrfs_extent_item);
 725                         num_refs = btrfs_extent_refs(leaf, ei);
 726                         extent_flags = btrfs_extent_flags(leaf, ei);
 727                 } else {
 728 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 729                         struct btrfs_extent_item_v0 *ei0;
 730                         BUG_ON(item_size != sizeof(*ei0));
 731                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 732                                              struct btrfs_extent_item_v0);
 733                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 734                         /* FIXME: this isn't correct for data */
 735                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 736 #else
 737                         BUG();
 738 #endif
 739                 }
 740                 BUG_ON(num_refs == 0);
 741         } else {
 742                 num_refs = 0;
 743                 extent_flags = 0;
 744                 ret = 0;
 745         }
 746
 747         if (!trans)
 748                 goto out;
 749
 750         delayed_refs = &trans->transaction->delayed_refs;
 751         spin_lock(&delayed_refs->lock);
 752         head = btrfs_find_delayed_ref_head(trans, bytenr);
 753         if (head) {
 754                 if (!mutex_trylock(&head->mutex)) {
 755                         atomic_inc(&head->node.refs);
 756                         spin_unlock(&delayed_refs->lock);
 757
 758                         btrfs_release_path(path);
 759
 760                         /*
 761                          * Mutex was contended, block until it's released and try
 762                          * again
 763                          */
 764                         mutex_lock(&head->mutex);
 765                         mutex_unlock(&head->mutex);
 766                         btrfs_put_delayed_ref(&head->node);
 767                         goto again;
 768                 }
 769                 if (head->extent_op && head->extent_op->update_flags)
 770                         extent_flags |= head->extent_op->flags_to_set;
 771                 else
 772                         BUG_ON(num_refs == 0);
 773
 774                 num_refs += head->node.ref_mod;
 775                 mutex_unlock(&head->mutex);
 776         }
 777         spin_unlock(&delayed_refs->lock);
 778 out:
 779         WARN_ON(num_refs == 0);
 780         if (refs)
 781                 *refs = num_refs;
 782         if (flags)
 783                 *flags = extent_flags;
 784 out_free:
 785         btrfs_free_path(path);
 786         return ret;
 787 }
 788
 789 /*
 790  * Back reference rules.  Back refs have three main goals:
 791  *
 792  * 1) differentiate between all holders of references to an extent so that
 793  *    when a reference is dropped we can make sure it was a valid reference
 794  *    before freeing the extent.
 795  *
 796  * 2) Provide enough information to quickly find the holders of an extent
 797  *    if we notice a given block is corrupted or bad.
 798  *
 799  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 800  *    maintenance.  This is actually the same as #2, but with a slightly
 801  *    different use case.
 802  *
 803  * There are two kinds of back refs. The implicit back refs is optimized
 804  * for pointers in non-shared tree blocks. For a given pointer in a block,
 805  * back refs of this kind provide information about the block's owner tree
 806  * and the pointer's key. These information allow us to find the block by
 807  * b-tree searching. The full back refs is for pointers in tree blocks not
 808  * referenced by their owner trees. The location of tree block is recorded
 809  * in the back refs. Actually the full back refs is generic, and can be
 810  * used in all cases the implicit back refs is used. The major shortcoming
 811  * of the full back refs is its overhead. Every time a tree block gets
 812  * COWed, we have to update back refs entry for all pointers in it.
 813  *
 814  * For a newly allocated tree block, we use implicit back refs for
 815  * pointers in it. This means most tree related operations only involve
 816  * implicit back refs. For a tree block created in old transaction, the
 817  * only way to drop a reference to it is COW it. So we can detect the
 818  * event that tree block loses its owner tree's reference and do the
 819  * back refs conversion.
 820  *
 821  * When a tree block is COW'd through a tree, there are four cases:
 822  *
 823  * The reference count of the block is one and the tree is the block's
 824  * owner tree. Nothing to do in this case.
 825  *
 826  * The reference count of the block is one and the tree is not the
 827  * block's owner tree. In this case, full back refs is used for pointers
 828  * in the block. Remove these full back refs, add implicit back refs for
 829  * every pointers in the new block.
 830  *
 831  * The reference count of the block is greater than one and the tree is
 832  * the block's owner tree. In this case, implicit back refs is used for
 833  * pointers in the block. Add full back refs for every pointers in the
 834  * block, increase lower level extents' reference counts. The original
 835  * implicit back refs are entailed to the new block.
 836  *
 837  * The reference count of the block is greater than one and the tree is
 838  * not the block's owner tree. Add implicit back refs for every pointer in
 839  * the new block, increase lower level extents' reference count.
 840  *
 841  * Back Reference Key composing:
 842  *
 843  * The key objectid corresponds to the first byte in the extent,
 844  * The key type is used to differentiate between types of back refs.
 845  * There are different meanings of the key offset for different types
 846  * of back refs.
 847  *
 848  * File extents can be referenced by:
 849  *
 850  * - multiple snapshots, subvolumes, or different generations in one subvol
 851  * - different files inside a single subvolume
 852  * - different offsets inside a file (bookend extents in file.c)
 853  *
 854  * The extent ref structure for the implicit back refs has fields for:
 855  *
 856  * - Objectid of the subvolume root
 857  * - objectid of the file holding the reference
 858  * - original offset in the file
 859  * - how many bookend extents
 860  *
 861  * The key offset for the implicit back refs is hash of the first
 862  * three fields.
 863  *
 864  * The extent ref structure for the full back refs has field for:
 865  *
 866  * - number of pointers in the tree leaf
 867  *
 868  * The key offset for the implicit back refs is the first byte of
 869  * the tree leaf
 870  *
 871  * When a file extent is allocated, The implicit back refs is used.
 872  * the fields are filled in:
 873  *
 874  *     (root_key.objectid, inode objectid, offset in file, 1)
 875  *
 876  * When a file extent is removed file truncation, we find the
 877  * corresponding implicit back refs and check the following fields:
 878  *
 879  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 880  *
 881  * Btree extents can be referenced by:
 882  *
 883  * - Different subvolumes
 884  *
 885  * Both the implicit back refs and the full back refs for tree blocks
 886  * only consist of key. The key offset for the implicit back refs is
 887  * objectid of block's owner tree. The key offset for the full back refs
 888  * is the first byte of parent block.
 889  *
 890  * When implicit back refs is used, information about the lowest key and
 891  * level of the tree block are required. These information are stored in
 892  * tree block info structure.
 893  */
 894
 895 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 896 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 897                                   struct btrfs_root *root,
 898                                   struct btrfs_path *path,
 899                                   u64 owner, u32 extra_size)
 900 {
 901         struct btrfs_extent_item *item;
 902         struct btrfs_extent_item_v0 *ei0;
 903         struct btrfs_extent_ref_v0 *ref0;
 904         struct btrfs_tree_block_info *bi;
 905         struct extent_buffer *leaf;
 906         struct btrfs_key key;
 907         struct btrfs_key found_key;
 908         u32 new_size = sizeof(*item);
 909         u64 refs;
 910         int ret;
 911
 912         leaf = path->nodes[0];
 913         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 914
 915         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 916         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 917                              struct btrfs_extent_item_v0);
 918         refs = btrfs_extent_refs_v0(leaf, ei0);
 919
 920         if (owner == (u64)-1) {
 921                 while (1) {
 922                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 923                                 ret = btrfs_next_leaf(root, path);
 924                                 if (ret < 0)
 925                                         return ret;
 926                                 BUG_ON(ret > 0);
 927                                 leaf = path->nodes[0];
 928                         }
 929                         btrfs_item_key_to_cpu(leaf, &found_key,
 930                                               path->slots[0]);
 931                         BUG_ON(key.objectid != found_key.objectid);
 932                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 933                                 path->slots[0]++;
 934                                 continue;
 935                         }
 936                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 937                                               struct btrfs_extent_ref_v0);
 938                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 939                         break;
 940                 }
 941         }
 942         btrfs_release_path(path);
 943
 944         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 945                 new_size += sizeof(*bi);
 946
 947         new_size -= sizeof(*ei0);
 948         ret = btrfs_search_slot(trans, root, &key, path,
 949                                 new_size + extra_size, 1);
 950         if (ret < 0)
 951                 return ret;
 952         BUG_ON(ret);
 953
 954         ret = btrfs_extend_item(trans, root, path, new_size);
 955
 956         leaf = path->nodes[0];
 957         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 958         btrfs_set_extent_refs(leaf, item, refs);
 959         /* FIXME: get real generation */
 960         btrfs_set_extent_generation(leaf, item, 0);
 961         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 962                 btrfs_set_extent_flags(leaf, item,
 963                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 964                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 965                 bi = (struct btrfs_tree_block_info *)(item + 1);
 966                 /* FIXME: get first key of the block */
 967                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 968                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 969         } else {
 970                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 971         }
 972         btrfs_mark_buffer_dirty(leaf);
 973         return 0;
 974 }
 975 #endif
 976
 977 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 978 {
 979         u32 high_crc = ~(u32)0;
 980         u32 low_crc = ~(u32)0;
 981         __le64 lenum;
 982
 983         lenum = cpu_to_le64(root_objectid);
 984         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 985         lenum = cpu_to_le64(owner);
 986         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 987         lenum = cpu_to_le64(offset);
 988         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 989
 990         return ((u64)high_crc << 31) ^ (u64)low_crc;
 991 }
 992
 993 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 994                                      struct btrfs_extent_data_ref *ref)
 995 {
 996         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 997                                     btrfs_extent_data_ref_objectid(leaf, ref),
 998                                     btrfs_extent_data_ref_offset(leaf, ref));
 999 }
1000
1001 static int match_extent_data_ref(struct extent_buffer *leaf,
1002                                  struct btrfs_extent_data_ref *ref,
1003                                  u64 root_objectid, u64 owner, u64 offset)
1004 {
1005         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1006             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1007             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1008                 return 0;
1009         return 1;
1010 }
1011
1012 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1013                                            struct btrfs_root *root,
1014                                            struct btrfs_path *path,
1015                                            u64 bytenr, u64 parent,
1016                                            u64 root_objectid,
1017                                            u64 owner, u64 offset)
1018 {
1019         struct btrfs_key key;
1020         struct btrfs_extent_data_ref *ref;
1021         struct extent_buffer *leaf;
1022         u32 nritems;
1023         int ret;
1024         int recow;
1025         int err = -ENOENT;
1026
1027         key.objectid = bytenr;
1028         if (parent) {
1029                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1030                 key.offset = parent;
1031         } else {
1032                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1033                 key.offset = hash_extent_data_ref(root_objectid,
1034                                                   owner, offset);
1035         }
1036 again:
1037         recow = 0;
1038         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1039         if (ret < 0) {
1040                 err = ret;
1041                 goto fail;
1042         }
1043
1044         if (parent) {
1045                 if (!ret)
1046                         return 0;
1047 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1048                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1049                 btrfs_release_path(path);
1050                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1051                 if (ret < 0) {
1052                         err = ret;
1053                         goto fail;
1054                 }
1055                 if (!ret)
1056                         return 0;
1057 #endif
1058                 goto fail;
1059         }
1060
1061         leaf = path->nodes[0];
1062         nritems = btrfs_header_nritems(leaf);
1063         while (1) {
1064                 if (path->slots[0] >= nritems) {
1065                         ret = btrfs_next_leaf(root, path);
1066                         if (ret < 0)
1067                                 err = ret;
1068                         if (ret)
1069                                 goto fail;
1070
1071                         leaf = path->nodes[0];
1072                         nritems = btrfs_header_nritems(leaf);
1073                         recow = 1;
1074                 }
1075
1076                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1077                 if (key.objectid != bytenr ||
1078                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1079                         goto fail;
1080
1081                 ref = btrfs_item_ptr(leaf, path->slots[0],
1082                                      struct btrfs_extent_data_ref);
1083
1084                 if (match_extent_data_ref(leaf, ref, root_objectid,
1085                                           owner, offset)) {
1086                         if (recow) {
1087                                 btrfs_release_path(path);
1088                                 goto again;
1089                         }
1090                         err = 0;
1091                         break;
1092                 }
1093                 path->slots[0]++;
1094         }
1095 fail:
1096         return err;
1097 }
1098
1099 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1100                                            struct btrfs_root *root,
1101                                            struct btrfs_path *path,
1102                                            u64 bytenr, u64 parent,
1103                                            u64 root_objectid, u64 owner,
1104                                            u64 offset, int refs_to_add)
1105 {
1106         struct btrfs_key key;
1107         struct extent_buffer *leaf;
1108         u32 size;
1109         u32 num_refs;
1110         int ret;
1111
1112         key.objectid = bytenr;
1113         if (parent) {
1114                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1115                 key.offset = parent;
1116                 size = sizeof(struct btrfs_shared_data_ref);
1117         } else {
1118                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1119                 key.offset = hash_extent_data_ref(root_objectid,
1120                                                   owner, offset);
1121                 size = sizeof(struct btrfs_extent_data_ref);
1122         }
1123
1124         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1125         if (ret && ret != -EEXIST)
1126                 goto fail;
1127
1128         leaf = path->nodes[0];
1129         if (parent) {
1130                 struct btrfs_shared_data_ref *ref;
1131                 ref = btrfs_item_ptr(leaf, path->slots[0],
1132                                      struct btrfs_shared_data_ref);
1133                 if (ret == 0) {
1134                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1135                 } else {
1136                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1137                         num_refs += refs_to_add;
1138                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1139                 }
1140         } else {
1141                 struct btrfs_extent_data_ref *ref;
1142                 while (ret == -EEXIST) {
1143                         ref = btrfs_item_ptr(leaf, path->slots[0],
1144                                              struct btrfs_extent_data_ref);
1145                         if (match_extent_data_ref(leaf, ref, root_objectid,
1146                                                   owner, offset))
1147                                 break;
1148                         btrfs_release_path(path);
1149                         key.offset++;
1150                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1151                                                       size);
1152                         if (ret && ret != -EEXIST)
1153                                 goto fail;
1154
1155                         leaf = path->nodes[0];
1156                 }
1157                 ref = btrfs_item_ptr(leaf, path->slots[0],
1158                                      struct btrfs_extent_data_ref);
1159                 if (ret == 0) {
1160                         btrfs_set_extent_data_ref_root(leaf, ref,
1161                                                        root_objectid);
1162                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1163                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1164                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1165                 } else {
1166                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1167                         num_refs += refs_to_add;
1168                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1169                 }
1170         }
1171         btrfs_mark_buffer_dirty(leaf);
1172         ret = 0;
1173 fail:
1174         btrfs_release_path(path);
1175         return ret;
1176 }
1177
1178 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1179                                            struct btrfs_root *root,
1180                                            struct btrfs_path *path,
1181                                            int refs_to_drop)
1182 {
1183         struct btrfs_key key;
1184         struct btrfs_extent_data_ref *ref1 = NULL;
1185         struct btrfs_shared_data_ref *ref2 = NULL;
1186         struct extent_buffer *leaf;
1187         u32 num_refs = 0;
1188         int ret = 0;
1189
1190         leaf = path->nodes[0];
1191         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1192
1193         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1194                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1195                                       struct btrfs_extent_data_ref);
1196                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1197         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1198                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1199                                       struct btrfs_shared_data_ref);
1200                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1201 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1202         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1203                 struct btrfs_extent_ref_v0 *ref0;
1204                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1205                                       struct btrfs_extent_ref_v0);
1206                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1207 #endif
1208         } else {
1209                 BUG();
1210         }
1211
1212         BUG_ON(num_refs < refs_to_drop);
1213         num_refs -= refs_to_drop;
1214
1215         if (num_refs == 0) {
1216                 ret = btrfs_del_item(trans, root, path);
1217         } else {
1218                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1219                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1220                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1221                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1222 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1223                 else {
1224                         struct btrfs_extent_ref_v0 *ref0;
1225                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1226                                         struct btrfs_extent_ref_v0);
1227                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1228                 }
1229 #endif
1230                 btrfs_mark_buffer_dirty(leaf);
1231         }
1232         return ret;
1233 }
1234
1235 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1236                                           struct btrfs_path *path,
1237                                           struct btrfs_extent_inline_ref *iref)
1238 {
1239         struct btrfs_key key;
1240         struct extent_buffer *leaf;
1241         struct btrfs_extent_data_ref *ref1;
1242         struct btrfs_shared_data_ref *ref2;
1243         u32 num_refs = 0;
1244
1245         leaf = path->nodes[0];
1246         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1247         if (iref) {
1248                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1249                     BTRFS_EXTENT_DATA_REF_KEY) {
1250                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1251                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1252                 } else {
1253                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1254                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1255                 }
1256         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1257                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1258                                       struct btrfs_extent_data_ref);
1259                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1260         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1261                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1262                                       struct btrfs_shared_data_ref);
1263                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1264 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1265         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1266                 struct btrfs_extent_ref_v0 *ref0;
1267                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1268                                       struct btrfs_extent_ref_v0);
1269                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1270 #endif
1271         } else {
1272                 WARN_ON(1);
1273         }
1274         return num_refs;
1275 }
1276
1277 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1278                                           struct btrfs_root *root,
1279                                           struct btrfs_path *path,
1280                                           u64 bytenr, u64 parent,
1281                                           u64 root_objectid)
1282 {
1283         struct btrfs_key key;
1284         int ret;
1285
1286         key.objectid = bytenr;
1287         if (parent) {
1288                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1289                 key.offset = parent;
1290         } else {
1291                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1292                 key.offset = root_objectid;
1293         }
1294
1295         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1296         if (ret > 0)
1297                 ret = -ENOENT;
1298 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1299         if (ret == -ENOENT && parent) {
1300                 btrfs_release_path(path);
1301                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1302                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1303                 if (ret > 0)
1304                         ret = -ENOENT;
1305         }
1306 #endif
1307         return ret;
1308 }
1309
1310 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1311                                           struct btrfs_root *root,
1312                                           struct btrfs_path *path,
1313                                           u64 bytenr, u64 parent,
1314                                           u64 root_objectid)
1315 {
1316         struct btrfs_key key;
1317         int ret;
1318
1319         key.objectid = bytenr;
1320         if (parent) {
1321                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1322                 key.offset = parent;
1323         } else {
1324                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1325                 key.offset = root_objectid;
1326         }
1327
1328         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1329         btrfs_release_path(path);
1330         return ret;
1331 }
1332
1333 static inline int extent_ref_type(u64 parent, u64 owner)
1334 {
1335         int type;
1336         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1337                 if (parent > 0)
1338                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1339                 else
1340                         type = BTRFS_TREE_BLOCK_REF_KEY;
1341         } else {
1342                 if (parent > 0)
1343                         type = BTRFS_SHARED_DATA_REF_KEY;
1344                 else
1345                         type = BTRFS_EXTENT_DATA_REF_KEY;
1346         }
1347         return type;
1348 }
1349
1350 static int find_next_key(struct btrfs_path *path, int level,
1351                          struct btrfs_key *key)
1352
1353 {
1354         for (; level < BTRFS_MAX_LEVEL; level++) {
1355                 if (!path->nodes[level])
1356                         break;
1357                 if (path->slots[level] + 1 >=
1358                     btrfs_header_nritems(path->nodes[level]))
1359                         continue;
1360                 if (level == 0)
1361                         btrfs_item_key_to_cpu(path->nodes[level], key,
1362                                               path->slots[level] + 1);
1363                 else
1364                         btrfs_node_key_to_cpu(path->nodes[level], key,
1365                                               path->slots[level] + 1);
1366                 return 0;
1367         }
1368         return 1;
1369 }
1370
1371 /*
1372  * look for inline back ref. if back ref is found, *ref_ret is set
1373  * to the address of inline back ref, and 0 is returned.
1374  *
1375  * if back ref isn't found, *ref_ret is set to the address where it
1376  * should be inserted, and -ENOENT is returned.
1377  *
1378  * if insert is true and there are too many inline back refs, the path
1379  * points to the extent item, and -EAGAIN is returned.
1380  *
1381  * NOTE: inline back refs are ordered in the same way that back ref
1382  *       items in the tree are ordered.
1383  */
1384 static noinline_for_stack
1385 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1386                                  struct btrfs_root *root,
1387                                  struct btrfs_path *path,
1388                                  struct btrfs_extent_inline_ref **ref_ret,
1389                                  u64 bytenr, u64 num_bytes,
1390                                  u64 parent, u64 root_objectid,
1391                                  u64 owner, u64 offset, int insert)
1392 {
1393         struct btrfs_key key;
1394         struct extent_buffer *leaf;
1395         struct btrfs_extent_item *ei;
1396         struct btrfs_extent_inline_ref *iref;
1397         u64 flags;
1398         u64 item_size;
1399         unsigned long ptr;
1400         unsigned long end;
1401         int extra_size;
1402         int type;
1403         int want;
1404         int ret;
1405         int err = 0;
1406
1407         key.objectid = bytenr;
1408         key.type = BTRFS_EXTENT_ITEM_KEY;
1409         key.offset = num_bytes;
1410
1411         want = extent_ref_type(parent, owner);
1412         if (insert) {
1413                 extra_size = btrfs_extent_inline_ref_size(want);
1414                 path->keep_locks = 1;
1415         } else
1416                 extra_size = -1;
1417         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1418         if (ret < 0) {
1419                 err = ret;
1420                 goto out;
1421         }
1422         BUG_ON(ret);
1423
1424         leaf = path->nodes[0];
1425         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1426 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1427         if (item_size < sizeof(*ei)) {
1428                 if (!insert) {
1429                         err = -ENOENT;
1430                         goto out;
1431                 }
1432                 ret = convert_extent_item_v0(trans, root, path, owner,
1433                                              extra_size);
1434                 if (ret < 0) {
1435                         err = ret;
1436                         goto out;
1437                 }
1438                 leaf = path->nodes[0];
1439                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1440         }
1441 #endif
1442         BUG_ON(item_size < sizeof(*ei));
1443
1444         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1445         flags = btrfs_extent_flags(leaf, ei);
1446
1447         ptr = (unsigned long)(ei + 1);
1448         end = (unsigned long)ei + item_size;
1449
1450         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1451                 ptr += sizeof(struct btrfs_tree_block_info);
1452                 BUG_ON(ptr > end);
1453         } else {
1454                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1455         }
1456
1457         err = -ENOENT;
1458         while (1) {
1459                 if (ptr >= end) {
1460                         WARN_ON(ptr > end);
1461                         break;
1462                 }
1463                 iref = (struct btrfs_extent_inline_ref *)ptr;
1464                 type = btrfs_extent_inline_ref_type(leaf, iref);
1465                 if (want < type)
1466                         break;
1467                 if (want > type) {
1468                         ptr += btrfs_extent_inline_ref_size(type);
1469                         continue;
1470                 }
1471
1472                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1473                         struct btrfs_extent_data_ref *dref;
1474                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1475                         if (match_extent_data_ref(leaf, dref, root_objectid,
1476                                                   owner, offset)) {
1477                                 err = 0;
1478                                 break;
1479                         }
1480                         if (hash_extent_data_ref_item(leaf, dref) <
1481                             hash_extent_data_ref(root_objectid, owner, offset))
1482                                 break;
1483                 } else {
1484                         u64 ref_offset;
1485                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1486                         if (parent > 0) {
1487                                 if (parent == ref_offset) {
1488                                         err = 0;
1489                                         break;
1490                                 }
1491                                 if (ref_offset < parent)
1492                                         break;
1493                         } else {
1494                                 if (root_objectid == ref_offset) {
1495                                         err = 0;
1496                                         break;
1497                                 }
1498                                 if (ref_offset < root_objectid)
1499                                         break;
1500                         }
1501                 }
1502                 ptr += btrfs_extent_inline_ref_size(type);
1503         }
1504         if (err == -ENOENT && insert) {
1505                 if (item_size + extra_size >=
1506                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1507                         err = -EAGAIN;
1508                         goto out;
1509                 }
1510                 /*
1511                  * To add new inline back ref, we have to make sure
1512                  * there is no corresponding back ref item.
1513                  * For simplicity, we just do not add new inline back
1514                  * ref if there is any kind of item for this block
1515                  */
1516                 if (find_next_key(path, 0, &key) == 0 &&
1517                     key.objectid == bytenr &&
1518                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1519                         err = -EAGAIN;
1520                         goto out;
1521                 }
1522         }
1523         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1524 out:
1525         if (insert) {
1526                 path->keep_locks = 0;
1527                 btrfs_unlock_up_safe(path, 1);
1528         }
1529         return err;
1530 }
1531
1532 /*
1533  * helper to add new inline back ref
1534  */
1535 static noinline_for_stack
1536 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1537                                 struct btrfs_root *root,
1538                                 struct btrfs_path *path,
1539                                 struct btrfs_extent_inline_ref *iref,
1540                                 u64 parent, u64 root_objectid,
1541                                 u64 owner, u64 offset, int refs_to_add,
1542                                 struct btrfs_delayed_extent_op *extent_op)
1543 {
1544         struct extent_buffer *leaf;
1545         struct btrfs_extent_item *ei;
1546         unsigned long ptr;
1547         unsigned long end;
1548         unsigned long item_offset;
1549         u64 refs;
1550         int size;
1551         int type;
1552         int ret;
1553
1554         leaf = path->nodes[0];
1555         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1556         item_offset = (unsigned long)iref - (unsigned long)ei;
1557
1558         type = extent_ref_type(parent, owner);
1559         size = btrfs_extent_inline_ref_size(type);
1560
1561         ret = btrfs_extend_item(trans, root, path, size);
1562
1563         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1564         refs = btrfs_extent_refs(leaf, ei);
1565         refs += refs_to_add;
1566         btrfs_set_extent_refs(leaf, ei, refs);
1567         if (extent_op)
1568                 __run_delayed_extent_op(extent_op, leaf, ei);
1569
1570         ptr = (unsigned long)ei + item_offset;
1571         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1572         if (ptr < end - size)
1573                 memmove_extent_buffer(leaf, ptr + size, ptr,
1574                                       end - size - ptr);
1575
1576         iref = (struct btrfs_extent_inline_ref *)ptr;
1577         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1578         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1579                 struct btrfs_extent_data_ref *dref;
1580                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1581                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1582                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1583                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1584                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1585         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1586                 struct btrfs_shared_data_ref *sref;
1587                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1588                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1589                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1590         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1591                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1592         } else {
1593                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1594         }
1595         btrfs_mark_buffer_dirty(leaf);
1596         return 0;
1597 }
1598
1599 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1600                                  struct btrfs_root *root,
1601                                  struct btrfs_path *path,
1602                                  struct btrfs_extent_inline_ref **ref_ret,
1603                                  u64 bytenr, u64 num_bytes, u64 parent,
1604                                  u64 root_objectid, u64 owner, u64 offset)
1605 {
1606         int ret;
1607
1608         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1609                                            bytenr, num_bytes, parent,
1610                                            root_objectid, owner, offset, 0);
1611         if (ret != -ENOENT)
1612                 return ret;
1613
1614         btrfs_release_path(path);
1615         *ref_ret = NULL;
1616
1617         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1618                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1619                                             root_objectid);
1620         } else {
1621                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1622                                              root_objectid, owner, offset);
1623         }
1624         return ret;
1625 }
1626
1627 /*
1628  * helper to update/remove inline back ref
1629  */
1630 static noinline_for_stack
1631 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1632                                  struct btrfs_root *root,
1633                                  struct btrfs_path *path,
1634                                  struct btrfs_extent_inline_ref *iref,
1635                                  int refs_to_mod,
1636                                  struct btrfs_delayed_extent_op *extent_op)
1637 {
1638         struct extent_buffer *leaf;
1639         struct btrfs_extent_item *ei;
1640         struct btrfs_extent_data_ref *dref = NULL;
1641         struct btrfs_shared_data_ref *sref = NULL;
1642         unsigned long ptr;
1643         unsigned long end;
1644         u32 item_size;
1645         int size;
1646         int type;
1647         int ret;
1648         u64 refs;
1649
1650         leaf = path->nodes[0];
1651         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1652         refs = btrfs_extent_refs(leaf, ei);
1653         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1654         refs += refs_to_mod;
1655         btrfs_set_extent_refs(leaf, ei, refs);
1656         if (extent_op)
1657                 __run_delayed_extent_op(extent_op, leaf, ei);
1658
1659         type = btrfs_extent_inline_ref_type(leaf, iref);
1660
1661         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1662                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1663                 refs = btrfs_extent_data_ref_count(leaf, dref);
1664         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1665                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1666                 refs = btrfs_shared_data_ref_count(leaf, sref);
1667         } else {
1668                 refs = 1;
1669                 BUG_ON(refs_to_mod != -1);
1670         }
1671
1672         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1673         refs += refs_to_mod;
1674
1675         if (refs > 0) {
1676                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1677                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1678                 else
1679                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1680         } else {
1681                 size =  btrfs_extent_inline_ref_size(type);
1682                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1683                 ptr = (unsigned long)iref;
1684                 end = (unsigned long)ei + item_size;
1685                 if (ptr + size < end)
1686                         memmove_extent_buffer(leaf, ptr, ptr + size,
1687                                               end - ptr - size);
1688                 item_size -= size;
1689                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1690         }
1691         btrfs_mark_buffer_dirty(leaf);
1692         return 0;
1693 }
1694
1695 static noinline_for_stack
1696 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1697                                  struct btrfs_root *root,
1698                                  struct btrfs_path *path,
1699                                  u64 bytenr, u64 num_bytes, u64 parent,
1700                                  u64 root_objectid, u64 owner,
1701                                  u64 offset, int refs_to_add,
1702                                  struct btrfs_delayed_extent_op *extent_op)
1703 {
1704         struct btrfs_extent_inline_ref *iref;
1705         int ret;
1706
1707         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1708                                            bytenr, num_bytes, parent,
1709                                            root_objectid, owner, offset, 1);
1710         if (ret == 0) {
1711                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1712                 ret = update_inline_extent_backref(trans, root, path, iref,
1713                                                    refs_to_add, extent_op);
1714         } else if (ret == -ENOENT) {
1715                 ret = setup_inline_extent_backref(trans, root, path, iref,
1716                                                   parent, root_objectid,
1717                                                   owner, offset, refs_to_add,
1718                                                   extent_op);
1719         }
1720         return ret;
1721 }
1722
1723 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1724                                  struct btrfs_root *root,
1725                                  struct btrfs_path *path,
1726                                  u64 bytenr, u64 parent, u64 root_objectid,
1727                                  u64 owner, u64 offset, int refs_to_add)
1728 {
1729         int ret;
1730         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1731                 BUG_ON(refs_to_add != 1);
1732                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1733                                             parent, root_objectid);
1734         } else {
1735                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1736                                              parent, root_objectid,
1737                                              owner, offset, refs_to_add);
1738         }
1739         return ret;
1740 }
1741
1742 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1743                                  struct btrfs_root *root,
1744                                  struct btrfs_path *path,
1745                                  struct btrfs_extent_inline_ref *iref,
1746                                  int refs_to_drop, int is_data)
1747 {
1748         int ret;
1749
1750         BUG_ON(!is_data && refs_to_drop != 1);
1751         if (iref) {
1752                 ret = update_inline_extent_backref(trans, root, path, iref,
1753                                                    -refs_to_drop, NULL);
1754         } else if (is_data) {
1755                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1756         } else {
1757                 ret = btrfs_del_item(trans, root, path);
1758         }
1759         return ret;
1760 }
1761
1762 static int btrfs_issue_discard(struct block_device *bdev,
1763                                 u64 start, u64 len)
1764 {
1765         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1766 }
1767
1768 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1769                                 u64 num_bytes, u64 *actual_bytes)
1770 {
1771         int ret;
1772         u64 discarded_bytes = 0;
1773         struct btrfs_multi_bio *multi = NULL;
1774
1775
1776         /* Tell the block device(s) that the sectors can be discarded */
1777         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1778                               bytenr, &num_bytes, &multi, 0);
1779         if (!ret) {
1780                 struct btrfs_bio_stripe *stripe = multi->stripes;
1781                 int i;
1782
1783
1784                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1785                         ret = btrfs_issue_discard(stripe->dev->bdev,
1786                                                   stripe->physical,
1787                                                   stripe->length);
1788                         if (!ret)
1789                                 discarded_bytes += stripe->length;
1790                         else if (ret != -EOPNOTSUPP)
1791                                 break;
1792                 }
1793                 kfree(multi);
1794         }
1795         if (discarded_bytes && ret == -EOPNOTSUPP)
1796                 ret = 0;
1797
1798         if (actual_bytes)
1799                 *actual_bytes = discarded_bytes;
1800
1801
1802         return ret;
1803 }
1804
1805 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1806                          struct btrfs_root *root,
1807                          u64 bytenr, u64 num_bytes, u64 parent,
1808                          u64 root_objectid, u64 owner, u64 offset)
1809 {
1810         int ret;
1811         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1812                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1813
1814         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1815                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1816                                         parent, root_objectid, (int)owner,
1817                                         BTRFS_ADD_DELAYED_REF, NULL);
1818         } else {
1819                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1820                                         parent, root_objectid, owner, offset,
1821                                         BTRFS_ADD_DELAYED_REF, NULL);
1822         }
1823         return ret;
1824 }
1825
1826 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1827                                   struct btrfs_root *root,
1828                                   u64 bytenr, u64 num_bytes,
1829                                   u64 parent, u64 root_objectid,
1830                                   u64 owner, u64 offset, int refs_to_add,
1831                                   struct btrfs_delayed_extent_op *extent_op)
1832 {
1833         struct btrfs_path *path;
1834         struct extent_buffer *leaf;
1835         struct btrfs_extent_item *item;
1836         u64 refs;
1837         int ret;
1838         int err = 0;
1839
1840         path = btrfs_alloc_path();
1841         if (!path)
1842                 return -ENOMEM;
1843
1844         path->reada = 1;
1845         path->leave_spinning = 1;
1846         /* this will setup the path even if it fails to insert the back ref */
1847         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1848                                            path, bytenr, num_bytes, parent,
1849                                            root_objectid, owner, offset,
1850                                            refs_to_add, extent_op);
1851         if (ret == 0)
1852                 goto out;
1853
1854         if (ret != -EAGAIN) {
1855                 err = ret;
1856                 goto out;
1857         }
1858
1859         leaf = path->nodes[0];
1860         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1861         refs = btrfs_extent_refs(leaf, item);
1862         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1863         if (extent_op)
1864                 __run_delayed_extent_op(extent_op, leaf, item);
1865
1866         btrfs_mark_buffer_dirty(leaf);
1867         btrfs_release_path(path);
1868
1869         path->reada = 1;
1870         path->leave_spinning = 1;
1871
1872         /* now insert the actual backref */
1873         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1874                                     path, bytenr, parent, root_objectid,
1875                                     owner, offset, refs_to_add);
1876         BUG_ON(ret);
1877 out:
1878         btrfs_free_path(path);
1879         return err;
1880 }
1881
1882 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1883                                 struct btrfs_root *root,
1884                                 struct btrfs_delayed_ref_node *node,
1885                                 struct btrfs_delayed_extent_op *extent_op,
1886                                 int insert_reserved)
1887 {
1888         int ret = 0;
1889         struct btrfs_delayed_data_ref *ref;
1890         struct btrfs_key ins;
1891         u64 parent = 0;
1892         u64 ref_root = 0;
1893         u64 flags = 0;
1894
1895         ins.objectid = node->bytenr;
1896         ins.offset = node->num_bytes;
1897         ins.type = BTRFS_EXTENT_ITEM_KEY;
1898
1899         ref = btrfs_delayed_node_to_data_ref(node);
1900         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1901                 parent = ref->parent;
1902         else
1903                 ref_root = ref->root;
1904
1905         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1906                 if (extent_op) {
1907                         BUG_ON(extent_op->update_key);
1908                         flags |= extent_op->flags_to_set;
1909                 }
1910                 ret = alloc_reserved_file_extent(trans, root,
1911                                                  parent, ref_root, flags,
1912                                                  ref->objectid, ref->offset,
1913                                                  &ins, node->ref_mod);
1914         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1915                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1916                                              node->num_bytes, parent,
1917                                              ref_root, ref->objectid,
1918                                              ref->offset, node->ref_mod,
1919                                              extent_op);
1920         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1921                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1922                                           node->num_bytes, parent,
1923                                           ref_root, ref->objectid,
1924                                           ref->offset, node->ref_mod,
1925                                           extent_op);
1926         } else {
1927                 BUG();
1928         }
1929         return ret;
1930 }
1931
1932 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1933                                     struct extent_buffer *leaf,
1934                                     struct btrfs_extent_item *ei)
1935 {
1936         u64 flags = btrfs_extent_flags(leaf, ei);
1937         if (extent_op->update_flags) {
1938                 flags |= extent_op->flags_to_set;
1939                 btrfs_set_extent_flags(leaf, ei, flags);
1940         }
1941
1942         if (extent_op->update_key) {
1943                 struct btrfs_tree_block_info *bi;
1944                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1945                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1946                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1947         }
1948 }
1949
1950 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1951                                  struct btrfs_root *root,
1952                                  struct btrfs_delayed_ref_node *node,
1953                                  struct btrfs_delayed_extent_op *extent_op)
1954 {
1955         struct btrfs_key key;
1956         struct btrfs_path *path;
1957         struct btrfs_extent_item *ei;
1958         struct extent_buffer *leaf;
1959         u32 item_size;
1960         int ret;
1961         int err = 0;
1962
1963         path = btrfs_alloc_path();
1964         if (!path)
1965                 return -ENOMEM;
1966
1967         key.objectid = node->bytenr;
1968         key.type = BTRFS_EXTENT_ITEM_KEY;
1969         key.offset = node->num_bytes;
1970
1971         path->reada = 1;
1972         path->leave_spinning = 1;
1973         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1974                                 path, 0, 1);
1975         if (ret < 0) {
1976                 err = ret;
1977                 goto out;
1978         }
1979         if (ret > 0) {
1980                 err = -EIO;
1981                 goto out;
1982         }
1983
1984         leaf = path->nodes[0];
1985         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1986 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1987         if (item_size < sizeof(*ei)) {
1988                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1989                                              path, (u64)-1, 0);
1990                 if (ret < 0) {
1991                         err = ret;
1992                         goto out;
1993                 }
1994                 leaf = path->nodes[0];
1995                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1996         }
1997 #endif
1998         BUG_ON(item_size < sizeof(*ei));
1999         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2000         __run_delayed_extent_op(extent_op, leaf, ei);
2001
2002         btrfs_mark_buffer_dirty(leaf);
2003 out:
2004         btrfs_free_path(path);
2005         return err;
2006 }
2007
2008 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2009                                 struct btrfs_root *root,
2010                                 struct btrfs_delayed_ref_node *node,
2011                                 struct btrfs_delayed_extent_op *extent_op,
2012                                 int insert_reserved)
2013 {
2014         int ret = 0;
2015         struct btrfs_delayed_tree_ref *ref;
2016         struct btrfs_key ins;
2017         u64 parent = 0;
2018         u64 ref_root = 0;
2019
2020         ins.objectid = node->bytenr;
2021         ins.offset = node->num_bytes;
2022         ins.type = BTRFS_EXTENT_ITEM_KEY;
2023
2024         ref = btrfs_delayed_node_to_tree_ref(node);
2025         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2026                 parent = ref->parent;
2027         else
2028                 ref_root = ref->root;
2029
2030         BUG_ON(node->ref_mod != 1);
2031         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2032                 BUG_ON(!extent_op || !extent_op->update_flags ||
2033                        !extent_op->update_key);
2034                 ret = alloc_reserved_tree_block(trans, root,
2035                                                 parent, ref_root,
2036                                                 extent_op->flags_to_set,
2037                                                 &extent_op->key,
2038                                                 ref->level, &ins);
2039         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2040                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2041                                              node->num_bytes, parent, ref_root,
2042                                              ref->level, 0, 1, extent_op);
2043         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2044                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2045                                           node->num_bytes, parent, ref_root,
2046                                           ref->level, 0, 1, extent_op);
2047         } else {
2048                 BUG();
2049         }
2050         return ret;
2051 }
2052
2053 /* helper function to actually process a single delayed ref entry */
2054 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2055                                struct btrfs_root *root,
2056                                struct btrfs_delayed_ref_node *node,
2057                                struct btrfs_delayed_extent_op *extent_op,
2058                                int insert_reserved)
2059 {
2060         int ret;
2061         if (btrfs_delayed_ref_is_head(node)) {
2062                 struct btrfs_delayed_ref_head *head;
2063                 /*
2064                  * we've hit the end of the chain and we were supposed
2065                  * to insert this extent into the tree.  But, it got
2066                  * deleted before we ever needed to insert it, so all
2067                  * we have to do is clean up the accounting
2068                  */
2069                 BUG_ON(extent_op);
2070                 head = btrfs_delayed_node_to_head(node);
2071                 if (insert_reserved) {
2072                         btrfs_pin_extent(root, node->bytenr,
2073                                          node->num_bytes, 1);
2074                         if (head->is_data) {
2075                                 ret = btrfs_del_csums(trans, root,
2076                                                       node->bytenr,
2077                                                       node->num_bytes);
2078                                 BUG_ON(ret);
2079                         }
2080                 }
2081                 mutex_unlock(&head->mutex);
2082                 return 0;
2083         }
2084
2085         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2086             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2087                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2088                                            insert_reserved);
2089         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2090                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2091                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2092                                            insert_reserved);
2093         else
2094                 BUG();
2095         return ret;
2096 }
2097
2098 static noinline struct btrfs_delayed_ref_node *
2099 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2100 {
2101         struct rb_node *node;
2102         struct btrfs_delayed_ref_node *ref;
2103         int action = BTRFS_ADD_DELAYED_REF;
2104 again:
2105         /*
2106          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2107          * this prevents ref count from going down to zero when
2108          * there still are pending delayed ref.
2109          */
2110         node = rb_prev(&head->node.rb_node);
2111         while (1) {
2112                 if (!node)
2113                         break;
2114                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2115                                 rb_node);
2116                 if (ref->bytenr != head->node.bytenr)
2117                         break;
2118                 if (ref->action == action)
2119                         return ref;
2120                 node = rb_prev(node);
2121         }
2122         if (action == BTRFS_ADD_DELAYED_REF) {
2123                 action = BTRFS_DROP_DELAYED_REF;
2124                 goto again;
2125         }
2126         return NULL;
2127 }
2128
2129 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2130                                        struct btrfs_root *root,
2131                                        struct list_head *cluster)
2132 {
2133         struct btrfs_delayed_ref_root *delayed_refs;
2134         struct btrfs_delayed_ref_node *ref;
2135         struct btrfs_delayed_ref_head *locked_ref = NULL;
2136         struct btrfs_delayed_extent_op *extent_op;
2137         int ret;
2138         int count = 0;
2139         int must_insert_reserved = 0;
2140
2141         delayed_refs = &trans->transaction->delayed_refs;
2142         while (1) {
2143                 if (!locked_ref) {
2144                         /* pick a new head ref from the cluster list */
2145                         if (list_empty(cluster))
2146                                 break;
2147
2148                         locked_ref = list_entry(cluster->next,
2149                                      struct btrfs_delayed_ref_head, cluster);
2150
2151                         /* grab the lock that says we are going to process
2152                          * all the refs for this head */
2153                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2154
2155                         /*
2156                          * we may have dropped the spin lock to get the head
2157                          * mutex lock, and that might have given someone else
2158                          * time to free the head.  If that's true, it has been
2159                          * removed from our list and we can move on.
2160                          */
2161                         if (ret == -EAGAIN) {
2162                                 locked_ref = NULL;
2163                                 count++;
2164                                 continue;
2165                         }
2166                 }
2167
2168                 /*
2169                  * record the must insert reserved flag before we
2170                  * drop the spin lock.
2171                  */
2172                 must_insert_reserved = locked_ref->must_insert_reserved;
2173                 locked_ref->must_insert_reserved = 0;
2174
2175                 extent_op = locked_ref->extent_op;
2176                 locked_ref->extent_op = NULL;
2177
2178                 /*
2179                  * locked_ref is the head node, so we have to go one
2180                  * node back for any delayed ref updates
2181                  */
2182                 ref = select_delayed_ref(locked_ref);
2183                 if (!ref) {
2184                         /* All delayed refs have been processed, Go ahead
2185                          * and send the head node to run_one_delayed_ref,
2186                          * so that any accounting fixes can happen
2187                          */
2188                         ref = &locked_ref->node;
2189
2190                         if (extent_op && must_insert_reserved) {
2191                                 kfree(extent_op);
2192                                 extent_op = NULL;
2193                         }
2194
2195                         if (extent_op) {
2196                                 spin_unlock(&delayed_refs->lock);
2197
2198                                 ret = run_delayed_extent_op(trans, root,
2199                                                             ref, extent_op);
2200                                 BUG_ON(ret);
2201                                 kfree(extent_op);
2202
2203                                 cond_resched();
2204                                 spin_lock(&delayed_refs->lock);
2205                                 continue;
2206                         }
2207
2208                         list_del_init(&locked_ref->cluster);
2209                         locked_ref = NULL;
2210                 }
2211
2212                 ref->in_tree = 0;
2213                 rb_erase(&ref->rb_node, &delayed_refs->root);
2214                 delayed_refs->num_entries--;
2215
2216                 spin_unlock(&delayed_refs->lock);
2217
2218                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2219                                           must_insert_reserved);
2220                 BUG_ON(ret);
2221
2222                 btrfs_put_delayed_ref(ref);
2223                 kfree(extent_op);
2224                 count++;
2225
2226                 cond_resched();
2227                 spin_lock(&delayed_refs->lock);
2228         }
2229         return count;
2230 }
2231
2232 /*
2233  * this starts processing the delayed reference count updates and
2234  * extent insertions we have queued up so far.  count can be
2235  * 0, which means to process everything in the tree at the start
2236  * of the run (but not newly added entries), or it can be some target
2237  * number you'd like to process.
2238  */
2239 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2240                            struct btrfs_root *root, unsigned long count)
2241 {
2242         struct rb_node *node;
2243         struct btrfs_delayed_ref_root *delayed_refs;
2244         struct btrfs_delayed_ref_node *ref;
2245         struct list_head cluster;
2246         int ret;
2247         int run_all = count == (unsigned long)-1;
2248         int run_most = 0;
2249
2250         if (root == root->fs_info->extent_root)
2251                 root = root->fs_info->tree_root;
2252
2253         delayed_refs = &trans->transaction->delayed_refs;
2254         INIT_LIST_HEAD(&cluster);
2255 again:
2256         spin_lock(&delayed_refs->lock);
2257         if (count == 0) {
2258                 count = delayed_refs->num_entries * 2;
2259                 run_most = 1;
2260         }
2261         while (1) {
2262                 if (!(run_all || run_most) &&
2263                     delayed_refs->num_heads_ready < 64)
2264                         break;
2265
2266                 /*
2267                  * go find something we can process in the rbtree.  We start at
2268                  * the beginning of the tree, and then build a cluster
2269                  * of refs to process starting at the first one we are able to
2270                  * lock
2271                  */
2272                 ret = btrfs_find_ref_cluster(trans, &cluster,
2273                                              delayed_refs->run_delayed_start);
2274                 if (ret)
2275                         break;
2276
2277                 ret = run_clustered_refs(trans, root, &cluster);
2278                 BUG_ON(ret < 0);
2279
2280                 count -= min_t(unsigned long, ret, count);
2281
2282                 if (count == 0)
2283                         break;
2284         }
2285
2286         if (run_all) {
2287                 node = rb_first(&delayed_refs->root);
2288                 if (!node)
2289                         goto out;
2290                 count = (unsigned long)-1;
2291
2292                 while (node) {
2293                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2294                                        rb_node);
2295                         if (btrfs_delayed_ref_is_head(ref)) {
2296                                 struct btrfs_delayed_ref_head *head;
2297
2298                                 head = btrfs_delayed_node_to_head(ref);
2299                                 atomic_inc(&ref->refs);
2300
2301                                 spin_unlock(&delayed_refs->lock);
2302                                 /*
2303                                  * Mutex was contended, block until it's
2304                                  * released and try again
2305                                  */
2306                                 mutex_lock(&head->mutex);
2307                                 mutex_unlock(&head->mutex);
2308
2309                                 btrfs_put_delayed_ref(ref);
2310                                 cond_resched();
2311                                 goto again;
2312                         }
2313                         node = rb_next(node);
2314                 }
2315                 spin_unlock(&delayed_refs->lock);
2316                 schedule_timeout(1);
2317                 goto again;
2318         }
2319 out:
2320         spin_unlock(&delayed_refs->lock);
2321         return 0;
2322 }
2323
2324 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2325                                 struct btrfs_root *root,
2326                                 u64 bytenr, u64 num_bytes, u64 flags,
2327                                 int is_data)
2328 {
2329         struct btrfs_delayed_extent_op *extent_op;
2330         int ret;
2331
2332         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2333         if (!extent_op)
2334                 return -ENOMEM;
2335
2336         extent_op->flags_to_set = flags;
2337         extent_op->update_flags = 1;
2338         extent_op->update_key = 0;
2339         extent_op->is_data = is_data ? 1 : 0;
2340
2341         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2342         if (ret)
2343                 kfree(extent_op);
2344         return ret;
2345 }
2346
2347 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2348                                       struct btrfs_root *root,
2349                                       struct btrfs_path *path,
2350                                       u64 objectid, u64 offset, u64 bytenr)
2351 {
2352         struct btrfs_delayed_ref_head *head;
2353         struct btrfs_delayed_ref_node *ref;
2354         struct btrfs_delayed_data_ref *data_ref;
2355         struct btrfs_delayed_ref_root *delayed_refs;
2356         struct rb_node *node;
2357         int ret = 0;
2358
2359         ret = -ENOENT;
2360         delayed_refs = &trans->transaction->delayed_refs;
2361         spin_lock(&delayed_refs->lock);
2362         head = btrfs_find_delayed_ref_head(trans, bytenr);
2363         if (!head)
2364                 goto out;
2365
2366         if (!mutex_trylock(&head->mutex)) {
2367                 atomic_inc(&head->node.refs);
2368                 spin_unlock(&delayed_refs->lock);
2369
2370                 btrfs_release_path(path);
2371
2372                 /*
2373                  * Mutex was contended, block until it's released and let
2374                  * caller try again
2375                  */
2376                 mutex_lock(&head->mutex);
2377                 mutex_unlock(&head->mutex);
2378                 btrfs_put_delayed_ref(&head->node);
2379                 return -EAGAIN;
2380         }
2381
2382         node = rb_prev(&head->node.rb_node);
2383         if (!node)
2384                 goto out_unlock;
2385
2386         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2387
2388         if (ref->bytenr != bytenr)
2389                 goto out_unlock;
2390
2391         ret = 1;
2392         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2393                 goto out_unlock;
2394
2395         data_ref = btrfs_delayed_node_to_data_ref(ref);
2396
2397         node = rb_prev(node);
2398         if (node) {
2399                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2400                 if (ref->bytenr == bytenr)
2401                         goto out_unlock;
2402         }
2403
2404         if (data_ref->root != root->root_key.objectid ||
2405             data_ref->objectid != objectid || data_ref->offset != offset)
2406                 goto out_unlock;
2407
2408         ret = 0;
2409 out_unlock:
2410         mutex_unlock(&head->mutex);
2411 out:
2412         spin_unlock(&delayed_refs->lock);
2413         return ret;
2414 }
2415
2416 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2417                                         struct btrfs_root *root,
2418                                         struct btrfs_path *path,
2419                                         u64 objectid, u64 offset, u64 bytenr)
2420 {
2421         struct btrfs_root *extent_root = root->fs_info->extent_root;
2422         struct extent_buffer *leaf;
2423         struct btrfs_extent_data_ref *ref;
2424         struct btrfs_extent_inline_ref *iref;
2425         struct btrfs_extent_item *ei;
2426         struct btrfs_key key;
2427         u32 item_size;
2428         int ret;
2429
2430         key.objectid = bytenr;
2431         key.offset = (u64)-1;
2432         key.type = BTRFS_EXTENT_ITEM_KEY;
2433
2434         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2435         if (ret < 0)
2436                 goto out;
2437         BUG_ON(ret == 0);
2438
2439         ret = -ENOENT;
2440         if (path->slots[0] == 0)
2441                 goto out;
2442
2443         path->slots[0]--;
2444         leaf = path->nodes[0];
2445         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2446
2447         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2448                 goto out;
2449
2450         ret = 1;
2451         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2452 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2453         if (item_size < sizeof(*ei)) {
2454                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2455                 goto out;
2456         }
2457 #endif
2458         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2459
2460         if (item_size != sizeof(*ei) +
2461             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2462                 goto out;
2463
2464         if (btrfs_extent_generation(leaf, ei) <=
2465             btrfs_root_last_snapshot(&root->root_item))
2466                 goto out;
2467
2468         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2469         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2470             BTRFS_EXTENT_DATA_REF_KEY)
2471                 goto out;
2472
2473         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2474         if (btrfs_extent_refs(leaf, ei) !=
2475             btrfs_extent_data_ref_count(leaf, ref) ||
2476             btrfs_extent_data_ref_root(leaf, ref) !=
2477             root->root_key.objectid ||
2478             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2479             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2480                 goto out;
2481
2482         ret = 0;
2483 out:
2484         return ret;
2485 }
2486
2487 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2488                           struct btrfs_root *root,
2489                           u64 objectid, u64 offset, u64 bytenr)
2490 {
2491         struct btrfs_path *path;
2492         int ret;
2493         int ret2;
2494
2495         path = btrfs_alloc_path();
2496         if (!path)
2497                 return -ENOENT;
2498
2499         do {
2500                 ret = check_committed_ref(trans, root, path, objectid,
2501                                           offset, bytenr);
2502                 if (ret && ret != -ENOENT)
2503                         goto out;
2504
2505                 ret2 = check_delayed_ref(trans, root, path, objectid,
2506                                          offset, bytenr);
2507         } while (ret2 == -EAGAIN);
2508
2509         if (ret2 && ret2 != -ENOENT) {
2510                 ret = ret2;
2511                 goto out;
2512         }
2513
2514         if (ret != -ENOENT || ret2 != -ENOENT)
2515                 ret = 0;
2516 out:
2517         btrfs_free_path(path);
2518         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2519                 WARN_ON(ret > 0);
2520         return ret;
2521 }
2522
2523 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2524                            struct btrfs_root *root,
2525                            struct extent_buffer *buf,
2526                            int full_backref, int inc)
2527 {
2528         u64 bytenr;
2529         u64 num_bytes;
2530         u64 parent;
2531         u64 ref_root;
2532         u32 nritems;
2533         struct btrfs_key key;
2534         struct btrfs_file_extent_item *fi;
2535         int i;
2536         int level;
2537         int ret = 0;
2538         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2539                             u64, u64, u64, u64, u64, u64);
2540
2541         ref_root = btrfs_header_owner(buf);
2542         nritems = btrfs_header_nritems(buf);
2543         level = btrfs_header_level(buf);
2544
2545         if (!root->ref_cows && level == 0)
2546                 return 0;
2547
2548         if (inc)
2549                 process_func = btrfs_inc_extent_ref;
2550         else
2551                 process_func = btrfs_free_extent;
2552
2553         if (full_backref)
2554                 parent = buf->start;
2555         else
2556                 parent = 0;
2557
2558         for (i = 0; i < nritems; i++) {
2559                 if (level == 0) {
2560                         btrfs_item_key_to_cpu(buf, &key, i);
2561                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2562                                 continue;
2563                         fi = btrfs_item_ptr(buf, i,
2564                                             struct btrfs_file_extent_item);
2565                         if (btrfs_file_extent_type(buf, fi) ==
2566                             BTRFS_FILE_EXTENT_INLINE)
2567                                 continue;
2568                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2569                         if (bytenr == 0)
2570                                 continue;
2571
2572                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2573                         key.offset -= btrfs_file_extent_offset(buf, fi);
2574                         ret = process_func(trans, root, bytenr, num_bytes,
2575                                            parent, ref_root, key.objectid,
2576                                            key.offset);
2577                         if (ret)
2578                                 goto fail;
2579                 } else {
2580                         bytenr = btrfs_node_blockptr(buf, i);
2581                         num_bytes = btrfs_level_size(root, level - 1);
2582                         ret = process_func(trans, root, bytenr, num_bytes,
2583                                            parent, ref_root, level - 1, 0);
2584                         if (ret)
2585                                 goto fail;
2586                 }
2587         }
2588         return 0;
2589 fail:
2590         BUG();
2591         return ret;
2592 }
2593
2594 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2595                   struct extent_buffer *buf, int full_backref)
2596 {
2597         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2598 }
2599
2600 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2601                   struct extent_buffer *buf, int full_backref)
2602 {
2603         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2604 }
2605
2606 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2607                                  struct btrfs_root *root,
2608                                  struct btrfs_path *path,
2609                                  struct btrfs_block_group_cache *cache)
2610 {
2611         int ret;
2612         struct btrfs_root *extent_root = root->fs_info->extent_root;
2613         unsigned long bi;
2614         struct extent_buffer *leaf;
2615
2616         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2617         if (ret < 0)
2618                 goto fail;
2619         BUG_ON(ret);
2620
2621         leaf = path->nodes[0];
2622         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2623         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2624         btrfs_mark_buffer_dirty(leaf);
2625         btrfs_release_path(path);
2626 fail:
2627         if (ret)
2628                 return ret;
2629         return 0;
2630
2631 }
2632
2633 static struct btrfs_block_group_cache *
2634 next_block_group(struct btrfs_root *root,
2635                  struct btrfs_block_group_cache *cache)
2636 {
2637         struct rb_node *node;
2638         spin_lock(&root->fs_info->block_group_cache_lock);
2639         node = rb_next(&cache->cache_node);
2640         btrfs_put_block_group(cache);
2641         if (node) {
2642                 cache = rb_entry(node, struct btrfs_block_group_cache,
2643                                  cache_node);
2644                 btrfs_get_block_group(cache);
2645         } else
2646                 cache = NULL;
2647         spin_unlock(&root->fs_info->block_group_cache_lock);
2648         return cache;
2649 }
2650
2651 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2652                             struct btrfs_trans_handle *trans,
2653                             struct btrfs_path *path)
2654 {
2655         struct btrfs_root *root = block_group->fs_info->tree_root;
2656         struct inode *inode = NULL;
2657         u64 alloc_hint = 0;
2658         int dcs = BTRFS_DC_ERROR;
2659         int num_pages = 0;
2660         int retries = 0;
2661         int ret = 0;
2662
2663         /*
2664          * If this block group is smaller than 100 megs don't bother caching the
2665          * block group.
2666          */
2667         if (block_group->key.offset < (100 * 1024 * 1024)) {
2668                 spin_lock(&block_group->lock);
2669                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2670                 spin_unlock(&block_group->lock);
2671                 return 0;
2672         }
2673
2674 again:
2675         inode = lookup_free_space_inode(root, block_group, path);
2676         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2677                 ret = PTR_ERR(inode);
2678                 btrfs_release_path(path);
2679                 goto out;
2680         }
2681
2682         if (IS_ERR(inode)) {
2683                 BUG_ON(retries);
2684                 retries++;
2685
2686                 if (block_group->ro)
2687                         goto out_free;
2688
2689                 ret = create_free_space_inode(root, trans, block_group, path);
2690                 if (ret)
2691                         goto out_free;
2692                 goto again;
2693         }
2694
2695         /*
2696          * We want to set the generation to 0, that way if anything goes wrong
2697          * from here on out we know not to trust this cache when we load up next
2698          * time.
2699          */
2700         BTRFS_I(inode)->generation = 0;
2701         ret = btrfs_update_inode(trans, root, inode);
2702         WARN_ON(ret);
2703
2704         if (i_size_read(inode) > 0) {
2705                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2706                                                       inode);
2707                 if (ret)
2708                         goto out_put;
2709         }
2710
2711         spin_lock(&block_group->lock);
2712         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2713                 /* We're not cached, don't bother trying to write stuff out */
2714                 dcs = BTRFS_DC_WRITTEN;
2715                 spin_unlock(&block_group->lock);
2716                 goto out_put;
2717         }
2718         spin_unlock(&block_group->lock);
2719
2720         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2721         if (!num_pages)
2722                 num_pages = 1;
2723
2724         /*
2725          * Just to make absolutely sure we have enough space, we're going to
2726          * preallocate 12 pages worth of space for each block group.  In
2727          * practice we ought to use at most 8, but we need extra space so we can
2728          * add our header and have a terminator between the extents and the
2729          * bitmaps.
2730          */
2731         num_pages *= 16;
2732         num_pages *= PAGE_CACHE_SIZE;
2733
2734         ret = btrfs_check_data_free_space(inode, num_pages);
2735         if (ret)
2736                 goto out_put;
2737
2738         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2739                                               num_pages, num_pages,
2740                                               &alloc_hint);
2741         if (!ret)
2742                 dcs = BTRFS_DC_SETUP;
2743         btrfs_free_reserved_data_space(inode, num_pages);
2744 out_put:
2745         iput(inode);
2746 out_free:
2747         btrfs_release_path(path);
2748 out:
2749         spin_lock(&block_group->lock);
2750         block_group->disk_cache_state = dcs;
2751         spin_unlock(&block_group->lock);
2752
2753         return ret;
2754 }
2755
2756 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2757                                    struct btrfs_root *root)
2758 {
2759         struct btrfs_block_group_cache *cache;
2760         int err = 0;
2761         struct btrfs_path *path;
2762         u64 last = 0;
2763
2764         path = btrfs_alloc_path();
2765         if (!path)
2766                 return -ENOMEM;
2767
2768 again:
2769         while (1) {
2770                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2771                 while (cache) {
2772                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2773                                 break;
2774                         cache = next_block_group(root, cache);
2775                 }
2776                 if (!cache) {
2777                         if (last == 0)
2778                                 break;
2779                         last = 0;
2780                         continue;
2781                 }
2782                 err = cache_save_setup(cache, trans, path);
2783                 last = cache->key.objectid + cache->key.offset;
2784                 btrfs_put_block_group(cache);
2785         }
2786
2787         while (1) {
2788                 if (last == 0) {
2789                         err = btrfs_run_delayed_refs(trans, root,
2790                                                      (unsigned long)-1);
2791                         BUG_ON(err);
2792                 }
2793
2794                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2795                 while (cache) {
2796                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2797                                 btrfs_put_block_group(cache);
2798                                 goto again;
2799                         }
2800
2801                         if (cache->dirty)
2802                                 break;
2803                         cache = next_block_group(root, cache);
2804                 }
2805                 if (!cache) {
2806                         if (last == 0)
2807                                 break;
2808                         last = 0;
2809                         continue;
2810                 }
2811
2812                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2813                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2814                 cache->dirty = 0;
2815                 last = cache->key.objectid + cache->key.offset;
2816
2817                 err = write_one_cache_group(trans, root, path, cache);
2818                 BUG_ON(err);
2819                 btrfs_put_block_group(cache);
2820         }
2821
2822         while (1) {
2823                 /*
2824                  * I don't think this is needed since we're just marking our
2825                  * preallocated extent as written, but just in case it can't
2826                  * hurt.
2827                  */
2828                 if (last == 0) {
2829                         err = btrfs_run_delayed_refs(trans, root,
2830                                                      (unsigned long)-1);
2831                         BUG_ON(err);
2832                 }
2833
2834                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2835                 while (cache) {
2836                         /*
2837                          * Really this shouldn't happen, but it could if we
2838                          * couldn't write the entire preallocated extent and
2839                          * splitting the extent resulted in a new block.
2840                          */
2841                         if (cache->dirty) {
2842                                 btrfs_put_block_group(cache);
2843                                 goto again;
2844                         }
2845                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2846                                 break;
2847                         cache = next_block_group(root, cache);
2848                 }
2849                 if (!cache) {
2850                         if (last == 0)
2851                                 break;
2852                         last = 0;
2853                         continue;
2854                 }
2855
2856                 btrfs_write_out_cache(root, trans, cache, path);
2857
2858                 /*
2859                  * If we didn't have an error then the cache state is still
2860                  * NEED_WRITE, so we can set it to WRITTEN.
2861                  */
2862                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2863                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2864                 last = cache->key.objectid + cache->key.offset;
2865                 btrfs_put_block_group(cache);
2866         }
2867
2868         btrfs_free_path(path);
2869         return 0;
2870 }
2871
2872 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2873 {
2874         struct btrfs_block_group_cache *block_group;
2875         int readonly = 0;
2876
2877         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2878         if (!block_group || block_group->ro)
2879                 readonly = 1;
2880         if (block_group)
2881                 btrfs_put_block_group(block_group);
2882         return readonly;
2883 }
2884
2885 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2886                              u64 total_bytes, u64 bytes_used,
2887                              struct btrfs_space_info **space_info)
2888 {
2889         struct btrfs_space_info *found;
2890         int i;
2891         int factor;
2892
2893         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2894                      BTRFS_BLOCK_GROUP_RAID10))
2895                 factor = 2;
2896         else
2897                 factor = 1;
2898
2899         found = __find_space_info(info, flags);
2900         if (found) {
2901                 spin_lock(&found->lock);
2902                 found->total_bytes += total_bytes;
2903                 found->disk_total += total_bytes * factor;
2904                 found->bytes_used += bytes_used;
2905                 found->disk_used += bytes_used * factor;
2906                 found->full = 0;
2907                 spin_unlock(&found->lock);
2908                 *space_info = found;
2909                 return 0;
2910         }
2911         found = kzalloc(sizeof(*found), GFP_NOFS);
2912         if (!found)
2913                 return -ENOMEM;
2914
2915         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2916                 INIT_LIST_HEAD(&found->block_groups[i]);
2917         init_rwsem(&found->groups_sem);
2918         spin_lock_init(&found->lock);
2919         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
2920                                 BTRFS_BLOCK_GROUP_SYSTEM |
2921                                 BTRFS_BLOCK_GROUP_METADATA);
2922         found->total_bytes = total_bytes;
2923         found->disk_total = total_bytes * factor;
2924         found->bytes_used = bytes_used;
2925         found->disk_used = bytes_used * factor;
2926         found->bytes_pinned = 0;
2927         found->bytes_reserved = 0;
2928         found->bytes_readonly = 0;
2929         found->bytes_may_use = 0;
2930         found->full = 0;
2931         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
2932         found->chunk_alloc = 0;
2933         found->flush = 0;
2934         init_waitqueue_head(&found->wait);
2935         *space_info = found;
2936         list_add_rcu(&found->list, &info->space_info);
2937         return 0;
2938 }
2939
2940 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2941 {
2942         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2943                                    BTRFS_BLOCK_GROUP_RAID1 |
2944                                    BTRFS_BLOCK_GROUP_RAID10 |
2945                                    BTRFS_BLOCK_GROUP_DUP);
2946         if (extra_flags) {
2947                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2948                         fs_info->avail_data_alloc_bits |= extra_flags;
2949                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2950                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2951                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2952                         fs_info->avail_system_alloc_bits |= extra_flags;
2953         }
2954 }
2955
2956 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2957 {
2958         /*
2959          * we add in the count of missing devices because we want
2960          * to make sure that any RAID levels on a degraded FS
2961          * continue to be honored.
2962          */
2963         u64 num_devices = root->fs_info->fs_devices->rw_devices +
2964                 root->fs_info->fs_devices->missing_devices;
2965
2966         if (num_devices == 1)
2967                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2968         if (num_devices < 4)
2969                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2970
2971         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2972             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2973                       BTRFS_BLOCK_GROUP_RAID10))) {
2974                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2975         }
2976
2977         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2978             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2979                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2980         }
2981
2982         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2983             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2984              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2985              (flags & BTRFS_BLOCK_GROUP_DUP)))
2986                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2987         return flags;
2988 }
2989
2990 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
2991 {
2992         if (flags & BTRFS_BLOCK_GROUP_DATA)
2993                 flags |= root->fs_info->avail_data_alloc_bits &
2994                          root->fs_info->data_alloc_profile;
2995         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2996                 flags |= root->fs_info->avail_system_alloc_bits &
2997                          root->fs_info->system_alloc_profile;
2998         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
2999                 flags |= root->fs_info->avail_metadata_alloc_bits &
3000                          root->fs_info->metadata_alloc_profile;
3001         return btrfs_reduce_alloc_profile(root, flags);
3002 }
3003
3004 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3005 {
3006         u64 flags;
3007
3008         if (data)
3009                 flags = BTRFS_BLOCK_GROUP_DATA;
3010         else if (root == root->fs_info->chunk_root)
3011                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3012         else
3013                 flags = BTRFS_BLOCK_GROUP_METADATA;
3014
3015         return get_alloc_profile(root, flags);
3016 }
3017
3018 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3019 {
3020         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3021                                                        BTRFS_BLOCK_GROUP_DATA);
3022 }
3023
3024 /*
3025  * This will check the space that the inode allocates from to make sure we have
3026  * enough space for bytes.
3027  */
3028 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3029 {
3030         struct btrfs_space_info *data_sinfo;
3031         struct btrfs_root *root = BTRFS_I(inode)->root;
3032         u64 used;
3033         int ret = 0, committed = 0, alloc_chunk = 1;
3034
3035         /* make sure bytes are sectorsize aligned */
3036         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3037
3038         if (root == root->fs_info->tree_root ||
3039             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3040                 alloc_chunk = 0;
3041                 committed = 1;
3042         }
3043
3044         data_sinfo = BTRFS_I(inode)->space_info;
3045         if (!data_sinfo)
3046                 goto alloc;
3047
3048 again:
3049         /* make sure we have enough space to handle the data first */
3050         spin_lock(&data_sinfo->lock);
3051         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3052                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3053                 data_sinfo->bytes_may_use;
3054
3055         if (used + bytes > data_sinfo->total_bytes) {
3056                 struct btrfs_trans_handle *trans;
3057
3058                 /*
3059                  * if we don't have enough free bytes in this space then we need
3060                  * to alloc a new chunk.
3061                  */
3062                 if (!data_sinfo->full && alloc_chunk) {
3063                         u64 alloc_target;
3064
3065                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3066                         spin_unlock(&data_sinfo->lock);
3067 alloc:
3068                         alloc_target = btrfs_get_alloc_profile(root, 1);
3069                         trans = btrfs_join_transaction(root);
3070                         if (IS_ERR(trans))
3071                                 return PTR_ERR(trans);
3072
3073                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3074                                              bytes + 2 * 1024 * 1024,
3075                                              alloc_target,
3076                                              CHUNK_ALLOC_NO_FORCE);
3077                         btrfs_end_transaction(trans, root);
3078                         if (ret < 0) {
3079                                 if (ret != -ENOSPC)
3080                                         return ret;
3081                                 else
3082                                         goto commit_trans;
3083                         }
3084
3085                         if (!data_sinfo) {
3086                                 btrfs_set_inode_space_info(root, inode);
3087                                 data_sinfo = BTRFS_I(inode)->space_info;
3088                         }
3089                         goto again;
3090                 }
3091
3092                 /*
3093                  * If we have less pinned bytes than we want to allocate then
3094                  * don't bother committing the transaction, it won't help us.
3095                  */
3096                 if (data_sinfo->bytes_pinned < bytes)
3097                         committed = 1;
3098                 spin_unlock(&data_sinfo->lock);
3099
3100                 /* commit the current transaction and try again */
3101 commit_trans:
3102                 if (!committed &&
3103                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3104                         committed = 1;
3105                         trans = btrfs_join_transaction(root);
3106                         if (IS_ERR(trans))
3107                                 return PTR_ERR(trans);
3108                         ret = btrfs_commit_transaction(trans, root);
3109                         if (ret)
3110                                 return ret;
3111                         goto again;
3112                 }
3113
3114                 return -ENOSPC;
3115         }
3116         data_sinfo->bytes_may_use += bytes;
3117         BTRFS_I(inode)->reserved_bytes += bytes;
3118         spin_unlock(&data_sinfo->lock);
3119
3120         return 0;
3121 }
3122
3123 /*
3124  * called when we are clearing an delalloc extent from the
3125  * inode's io_tree or there was an error for whatever reason
3126  * after calling btrfs_check_data_free_space
3127  */
3128 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3129 {
3130         struct btrfs_root *root = BTRFS_I(inode)->root;
3131         struct btrfs_space_info *data_sinfo;
3132
3133         /* make sure bytes are sectorsize aligned */
3134         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3135
3136         data_sinfo = BTRFS_I(inode)->space_info;
3137         spin_lock(&data_sinfo->lock);
3138         data_sinfo->bytes_may_use -= bytes;
3139         BTRFS_I(inode)->reserved_bytes -= bytes;
3140         spin_unlock(&data_sinfo->lock);
3141 }
3142
3143 static void force_metadata_allocation(struct btrfs_fs_info *info)
3144 {
3145         struct list_head *head = &info->space_info;
3146         struct btrfs_space_info *found;
3147
3148         rcu_read_lock();
3149         list_for_each_entry_rcu(found, head, list) {
3150                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3151                         found->force_alloc = CHUNK_ALLOC_FORCE;
3152         }
3153         rcu_read_unlock();
3154 }
3155
3156 static int should_alloc_chunk(struct btrfs_root *root,
3157                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3158                               int force)
3159 {
3160         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3161         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3162         u64 thresh;
3163
3164         if (force == CHUNK_ALLOC_FORCE)
3165                 return 1;
3166
3167         /*
3168          * in limited mode, we want to have some free space up to
3169          * about 1% of the FS size.
3170          */
3171         if (force == CHUNK_ALLOC_LIMITED) {
3172                 thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3173                 thresh = max_t(u64, 64 * 1024 * 1024,
3174                                div_factor_fine(thresh, 1));
3175
3176                 if (num_bytes - num_allocated < thresh)
3177                         return 1;
3178         }
3179
3180         /*
3181          * we have two similar checks here, one based on percentage
3182          * and once based on a hard number of 256MB.  The idea
3183          * is that if we have a good amount of free
3184          * room, don't allocate a chunk.  A good mount is
3185          * less than 80% utilized of the chunks we have allocated,
3186          * or more than 256MB free
3187          */
3188         if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3189                 return 0;
3190
3191         if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
3192                 return 0;
3193
3194         thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3195
3196         /* 256MB or 5% of the FS */
3197         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
3198
3199         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
3200                 return 0;
3201         return 1;
3202 }
3203
3204 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3205                           struct btrfs_root *extent_root, u64 alloc_bytes,
3206                           u64 flags, int force)
3207 {
3208         struct btrfs_space_info *space_info;
3209         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3210         int wait_for_alloc = 0;
3211         int ret = 0;
3212
3213         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3214
3215         space_info = __find_space_info(extent_root->fs_info, flags);
3216         if (!space_info) {
3217                 ret = update_space_info(extent_root->fs_info, flags,
3218                                         0, 0, &space_info);
3219                 BUG_ON(ret);
3220         }
3221         BUG_ON(!space_info);
3222
3223 again:
3224         spin_lock(&space_info->lock);
3225         if (space_info->force_alloc)
3226                 force = space_info->force_alloc;
3227         if (space_info->full) {
3228                 spin_unlock(&space_info->lock);
3229                 return 0;
3230         }
3231
3232         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3233                 spin_unlock(&space_info->lock);
3234                 return 0;
3235         } else if (space_info->chunk_alloc) {
3236                 wait_for_alloc = 1;
3237         } else {
3238                 space_info->chunk_alloc = 1;
3239         }
3240
3241         spin_unlock(&space_info->lock);
3242
3243         mutex_lock(&fs_info->chunk_mutex);
3244
3245         /*
3246          * The chunk_mutex is held throughout the entirety of a chunk
3247          * allocation, so once we've acquired the chunk_mutex we know that the
3248          * other guy is done and we need to recheck and see if we should
3249          * allocate.
3250          */
3251         if (wait_for_alloc) {
3252                 mutex_unlock(&fs_info->chunk_mutex);
3253                 wait_for_alloc = 0;
3254                 goto again;
3255         }
3256
3257         /*
3258          * If we have mixed data/metadata chunks we want to make sure we keep
3259          * allocating mixed chunks instead of individual chunks.
3260          */
3261         if (btrfs_mixed_space_info(space_info))
3262                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3263
3264         /*
3265          * if we're doing a data chunk, go ahead and make sure that
3266          * we keep a reasonable number of metadata chunks allocated in the
3267          * FS as well.
3268          */
3269         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3270                 fs_info->data_chunk_allocations++;
3271                 if (!(fs_info->data_chunk_allocations %
3272                       fs_info->metadata_ratio))
3273                         force_metadata_allocation(fs_info);
3274         }
3275
3276         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3277         if (ret < 0 && ret != -ENOSPC)
3278                 goto out;
3279
3280         spin_lock(&space_info->lock);
3281         if (ret)
3282                 space_info->full = 1;
3283         else
3284                 ret = 1;
3285
3286         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3287         space_info->chunk_alloc = 0;
3288         spin_unlock(&space_info->lock);
3289 out:
3290         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3291         return ret;
3292 }
3293
3294 /*
3295  * shrink metadata reservation for delalloc
3296  */
3297 static int shrink_delalloc(struct btrfs_trans_handle *trans,
3298                            struct btrfs_root *root, u64 to_reclaim, int sync)
3299 {
3300         struct btrfs_block_rsv *block_rsv;
3301         struct btrfs_space_info *space_info;
3302         u64 reserved;
3303         u64 max_reclaim;
3304         u64 reclaimed = 0;
3305         long time_left;
3306         int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3307         int loops = 0;
3308         unsigned long progress;
3309
3310         block_rsv = &root->fs_info->delalloc_block_rsv;
3311         space_info = block_rsv->space_info;
3312
3313         smp_mb();
3314         reserved = space_info->bytes_reserved;
3315         progress = space_info->reservation_progress;
3316
3317         if (reserved == 0)
3318                 return 0;
3319
3320         smp_mb();
3321         if (root->fs_info->delalloc_bytes == 0) {
3322                 if (trans)
3323                         return 0;
3324                 btrfs_wait_ordered_extents(root, 0, 0);
3325                 return 0;
3326         }
3327
3328         max_reclaim = min(reserved, to_reclaim);
3329
3330         while (loops < 1024) {
3331                 /* have the flusher threads jump in and do some IO */
3332                 smp_mb();
3333                 nr_pages = min_t(unsigned long, nr_pages,
3334                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3335                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
3336
3337                 spin_lock(&space_info->lock);
3338                 if (reserved > space_info->bytes_reserved)
3339                         reclaimed += reserved - space_info->bytes_reserved;
3340                 reserved = space_info->bytes_reserved;
3341                 spin_unlock(&space_info->lock);
3342
3343                 loops++;
3344
3345                 if (reserved == 0 || reclaimed >= max_reclaim)
3346                         break;
3347
3348                 if (trans && trans->transaction->blocked)
3349                         return -EAGAIN;
3350
3351                 time_left = schedule_timeout_interruptible(1);
3352
3353                 /* We were interrupted, exit */
3354                 if (time_left)
3355                         break;
3356
3357                 /* we've kicked the IO a few times, if anything has been freed,
3358                  * exit.  There is no sense in looping here for a long time
3359                  * when we really need to commit the transaction, or there are
3360                  * just too many writers without enough free space
3361                  */
3362
3363                 if (loops > 3) {
3364                         smp_mb();
3365                         if (progress != space_info->reservation_progress)
3366                                 break;
3367                 }
3368
3369         }
3370         if (reclaimed >= to_reclaim && !trans)
3371                 btrfs_wait_ordered_extents(root, 0, 0);
3372         return reclaimed >= to_reclaim;
3373 }
3374
3375 /*
3376  * Retries tells us how many times we've called reserve_metadata_bytes.  The
3377  * idea is if this is the first call (retries == 0) then we will add to our
3378  * reserved count if we can't make the allocation in order to hold our place
3379  * while we go and try and free up space.  That way for retries > 1 we don't try
3380  * and add space, we just check to see if the amount of unused space is >= the
3381  * total space, meaning that our reservation is valid.
3382  *
3383  * However if we don't intend to retry this reservation, pass -1 as retries so
3384  * that it short circuits this logic.
3385  */
3386 static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
3387                                   struct btrfs_root *root,
3388                                   struct btrfs_block_rsv *block_rsv,
3389                                   u64 orig_bytes, int flush)
3390 {
3391         struct btrfs_space_info *space_info = block_rsv->space_info;
3392         u64 unused;
3393         u64 num_bytes = orig_bytes;
3394         int retries = 0;
3395         int ret = 0;
3396         bool committed = false;
3397         bool flushing = false;
3398
3399 again:
3400         ret = 0;
3401         spin_lock(&space_info->lock);
3402         /*
3403          * We only want to wait if somebody other than us is flushing and we are
3404          * actually alloed to flush.
3405          */
3406         while (flush && !flushing && space_info->flush) {
3407                 spin_unlock(&space_info->lock);
3408                 /*
3409                  * If we have a trans handle we can't wait because the flusher
3410                  * may have to commit the transaction, which would mean we would
3411                  * deadlock since we are waiting for the flusher to finish, but
3412                  * hold the current transaction open.
3413                  */
3414                 if (trans)
3415                         return -EAGAIN;
3416                 ret = wait_event_interruptible(space_info->wait,
3417                                                !space_info->flush);
3418                 /* Must have been interrupted, return */
3419                 if (ret)
3420                         return -EINTR;
3421
3422                 spin_lock(&space_info->lock);
3423         }
3424
3425         ret = -ENOSPC;
3426         unused = space_info->bytes_used + space_info->bytes_reserved +
3427                  space_info->bytes_pinned + space_info->bytes_readonly +
3428                  space_info->bytes_may_use;
3429
3430         /*
3431          * The idea here is that we've not already over-reserved the block group
3432          * then we can go ahead and save our reservation first and then start
3433          * flushing if we need to.  Otherwise if we've already overcommitted
3434          * lets start flushing stuff first and then come back and try to make
3435          * our reservation.
3436          */
3437         if (unused <= space_info->total_bytes) {
3438                 unused = space_info->total_bytes - unused;
3439                 if (unused >= num_bytes) {
3440                         space_info->bytes_reserved += orig_bytes;
3441                         ret = 0;
3442                 } else {
3443                         /*
3444                          * Ok set num_bytes to orig_bytes since we aren't
3445                          * overocmmitted, this way we only try and reclaim what
3446                          * we need.
3447                          */
3448                         num_bytes = orig_bytes;
3449                 }
3450         } else {
3451                 /*
3452                  * Ok we're over committed, set num_bytes to the overcommitted
3453                  * amount plus the amount of bytes that we need for this
3454                  * reservation.
3455                  */
3456                 num_bytes = unused - space_info->total_bytes +
3457                         (orig_bytes * (retries + 1));
3458         }
3459
3460         /*
3461          * Couldn't make our reservation, save our place so while we're trying
3462          * to reclaim space we can actually use it instead of somebody else
3463          * stealing it from us.
3464          */
3465         if (ret && flush) {
3466                 flushing = true;
3467                 space_info->flush = 1;
3468         }
3469
3470         spin_unlock(&space_info->lock);
3471
3472         if (!ret || !flush)
3473                 goto out;
3474
3475         /*
3476          * We do synchronous shrinking since we don't actually unreserve
3477          * metadata until after the IO is completed.
3478          */
3479         ret = shrink_delalloc(trans, root, num_bytes, 1);
3480         if (ret < 0)
3481                 goto out;
3482
3483         ret = 0;
3484
3485         /*
3486          * So if we were overcommitted it's possible that somebody else flushed
3487          * out enough space and we simply didn't have enough space to reclaim,
3488          * so go back around and try again.
3489          */
3490         if (retries < 2) {
3491                 retries++;
3492                 goto again;
3493         }
3494
3495         /*
3496          * Not enough space to be reclaimed, don't bother committing the
3497          * transaction.
3498          */
3499         spin_lock(&space_info->lock);
3500         if (space_info->bytes_pinned < orig_bytes)
3501                 ret = -ENOSPC;
3502         spin_unlock(&space_info->lock);
3503         if (ret)
3504                 goto out;
3505
3506         ret = -EAGAIN;
3507         if (trans)
3508                 goto out;
3509
3510         ret = -ENOSPC;
3511         if (committed)
3512                 goto out;
3513
3514         trans = btrfs_join_transaction(root);
3515         if (IS_ERR(trans))
3516                 goto out;
3517         ret = btrfs_commit_transaction(trans, root);
3518         if (!ret) {
3519                 trans = NULL;
3520                 committed = true;
3521                 goto again;
3522         }
3523
3524 out:
3525         if (flushing) {
3526                 spin_lock(&space_info->lock);
3527                 space_info->flush = 0;
3528                 wake_up_all(&space_info->wait);
3529                 spin_unlock(&space_info->lock);
3530         }
3531         return ret;
3532 }
3533
3534 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3535                                              struct btrfs_root *root)
3536 {
3537         struct btrfs_block_rsv *block_rsv;
3538         if (root->ref_cows)
3539                 block_rsv = trans->block_rsv;
3540         else
3541                 block_rsv = root->block_rsv;
3542
3543         if (!block_rsv)
3544                 block_rsv = &root->fs_info->empty_block_rsv;
3545
3546         return block_rsv;
3547 }
3548
3549 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3550                                u64 num_bytes)
3551 {
3552         int ret = -ENOSPC;
3553         spin_lock(&block_rsv->lock);
3554         if (block_rsv->reserved >= num_bytes) {
3555                 block_rsv->reserved -= num_bytes;
3556                 if (block_rsv->reserved < block_rsv->size)
3557                         block_rsv->full = 0;
3558                 ret = 0;
3559         }
3560         spin_unlock(&block_rsv->lock);
3561         return ret;
3562 }
3563
3564 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3565                                 u64 num_bytes, int update_size)
3566 {
3567         spin_lock(&block_rsv->lock);
3568         block_rsv->reserved += num_bytes;
3569         if (update_size)
3570                 block_rsv->size += num_bytes;
3571         else if (block_rsv->reserved >= block_rsv->size)
3572                 block_rsv->full = 1;
3573         spin_unlock(&block_rsv->lock);
3574 }
3575
3576 static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3577                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3578 {
3579         struct btrfs_space_info *space_info = block_rsv->space_info;
3580
3581         spin_lock(&block_rsv->lock);
3582         if (num_bytes == (u64)-1)
3583                 num_bytes = block_rsv->size;
3584         block_rsv->size -= num_bytes;
3585         if (block_rsv->reserved >= block_rsv->size) {
3586                 num_bytes = block_rsv->reserved - block_rsv->size;
3587                 block_rsv->reserved = block_rsv->size;
3588                 block_rsv->full = 1;
3589         } else {
3590                 num_bytes = 0;
3591         }
3592         spin_unlock(&block_rsv->lock);
3593
3594         if (num_bytes > 0) {
3595                 if (dest) {
3596                         spin_lock(&dest->lock);
3597                         if (!dest->full) {
3598                                 u64 bytes_to_add;
3599
3600                                 bytes_to_add = dest->size - dest->reserved;
3601                                 bytes_to_add = min(num_bytes, bytes_to_add);
3602                                 dest->reserved += bytes_to_add;
3603                                 if (dest->reserved >= dest->size)
3604                                         dest->full = 1;
3605                                 num_bytes -= bytes_to_add;
3606                         }
3607                         spin_unlock(&dest->lock);
3608                 }
3609                 if (num_bytes) {
3610                         spin_lock(&space_info->lock);
3611                         space_info->bytes_reserved -= num_bytes;
3612                         space_info->reservation_progress++;
3613                         spin_unlock(&space_info->lock);
3614                 }
3615         }
3616 }
3617
3618 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3619                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3620 {
3621         int ret;
3622
3623         ret = block_rsv_use_bytes(src, num_bytes);
3624         if (ret)
3625                 return ret;
3626
3627         block_rsv_add_bytes(dst, num_bytes, 1);
3628         return 0;
3629 }
3630
3631 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3632 {
3633         memset(rsv, 0, sizeof(*rsv));
3634         spin_lock_init(&rsv->lock);
3635         atomic_set(&rsv->usage, 1);
3636         rsv->priority = 6;
3637         INIT_LIST_HEAD(&rsv->list);
3638 }
3639
3640 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3641 {
3642         struct btrfs_block_rsv *block_rsv;
3643         struct btrfs_fs_info *fs_info = root->fs_info;
3644
3645         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3646         if (!block_rsv)
3647                 return NULL;
3648
3649         btrfs_init_block_rsv(block_rsv);
3650         block_rsv->space_info = __find_space_info(fs_info,
3651                                                   BTRFS_BLOCK_GROUP_METADATA);
3652         return block_rsv;
3653 }
3654
3655 void btrfs_free_block_rsv(struct btrfs_root *root,
3656                           struct btrfs_block_rsv *rsv)
3657 {
3658         if (rsv && atomic_dec_and_test(&rsv->usage)) {
3659                 btrfs_block_rsv_release(root, rsv, (u64)-1);
3660                 if (!rsv->durable)
3661                         kfree(rsv);
3662         }
3663 }
3664
3665 /*
3666  * make the block_rsv struct be able to capture freed space.
3667  * the captured space will re-add to the the block_rsv struct
3668  * after transaction commit
3669  */
3670 void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
3671                                  struct btrfs_block_rsv *block_rsv)
3672 {
3673         block_rsv->durable = 1;
3674         mutex_lock(&fs_info->durable_block_rsv_mutex);
3675         list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
3676         mutex_unlock(&fs_info->durable_block_rsv_mutex);
3677 }
3678
3679 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
3680                         struct btrfs_root *root,
3681                         struct btrfs_block_rsv *block_rsv,
3682                         u64 num_bytes)
3683 {
3684         int ret;
3685
3686         if (num_bytes == 0)
3687                 return 0;
3688
3689         ret = reserve_metadata_bytes(trans, root, block_rsv, num_bytes, 1);
3690         if (!ret) {
3691                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3692                 return 0;
3693         }
3694
3695         return ret;
3696 }
3697
3698 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
3699                           struct btrfs_root *root,
3700                           struct btrfs_block_rsv *block_rsv,
3701                           u64 min_reserved, int min_factor)
3702 {
3703         u64 num_bytes = 0;
3704         int commit_trans = 0;
3705         int ret = -ENOSPC;
3706
3707         if (!block_rsv)
3708                 return 0;
3709
3710         spin_lock(&block_rsv->lock);
3711         if (min_factor > 0)
3712                 num_bytes = div_factor(block_rsv->size, min_factor);
3713         if (min_reserved > num_bytes)
3714                 num_bytes = min_reserved;
3715
3716         if (block_rsv->reserved >= num_bytes) {
3717                 ret = 0;
3718         } else {
3719                 num_bytes -= block_rsv->reserved;
3720                 if (block_rsv->durable &&
3721                     block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
3722                         commit_trans = 1;
3723         }
3724         spin_unlock(&block_rsv->lock);
3725         if (!ret)
3726                 return 0;
3727
3728         if (block_rsv->refill_used) {
3729                 ret = reserve_metadata_bytes(trans, root, block_rsv,
3730                                              num_bytes, 0);
3731                 if (!ret) {
3732                         block_rsv_add_bytes(block_rsv, num_bytes, 0);
3733                         return 0;
3734                 }
3735         }
3736
3737         if (commit_trans) {
3738                 if (trans)
3739                         return -EAGAIN;
3740                 trans = btrfs_join_transaction(root);
3741                 BUG_ON(IS_ERR(trans));
3742                 ret = btrfs_commit_transaction(trans, root);
3743                 return 0;
3744         }
3745
3746         return -ENOSPC;
3747 }
3748
3749 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3750                             struct btrfs_block_rsv *dst_rsv,
3751                             u64 num_bytes)
3752 {
3753         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3754 }
3755
3756 void btrfs_block_rsv_release(struct btrfs_root *root,
3757                              struct btrfs_block_rsv *block_rsv,
3758                              u64 num_bytes)
3759 {
3760         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3761         if (global_rsv->full || global_rsv == block_rsv ||
3762             block_rsv->space_info != global_rsv->space_info)
3763                 global_rsv = NULL;
3764         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3765 }
3766
3767 /*
3768  * helper to calculate size of global block reservation.
3769  * the desired value is sum of space used by extent tree,
3770  * checksum tree and root tree
3771  */
3772 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3773 {
3774         struct btrfs_space_info *sinfo;
3775         u64 num_bytes;
3776         u64 meta_used;
3777         u64 data_used;
3778         int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
3779
3780         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3781         spin_lock(&sinfo->lock);
3782         data_used = sinfo->bytes_used;
3783         spin_unlock(&sinfo->lock);
3784
3785         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3786         spin_lock(&sinfo->lock);
3787         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
3788                 data_used = 0;
3789         meta_used = sinfo->bytes_used;
3790         spin_unlock(&sinfo->lock);
3791
3792         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3793                     csum_size * 2;
3794         num_bytes += div64_u64(data_used + meta_used, 50);
3795
3796         if (num_bytes * 3 > meta_used)
3797                 num_bytes = div64_u64(meta_used, 3);
3798
3799         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3800 }
3801
3802 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3803 {
3804         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3805         struct btrfs_space_info *sinfo = block_rsv->space_info;
3806         u64 num_bytes;
3807
3808         num_bytes = calc_global_metadata_size(fs_info);
3809
3810         spin_lock(&block_rsv->lock);
3811         spin_lock(&sinfo->lock);
3812
3813         block_rsv->size = num_bytes;
3814
3815         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
3816                     sinfo->bytes_reserved + sinfo->bytes_readonly +
3817                     sinfo->bytes_may_use;
3818
3819         if (sinfo->total_bytes > num_bytes) {
3820                 num_bytes = sinfo->total_bytes - num_bytes;
3821                 block_rsv->reserved += num_bytes;
3822                 sinfo->bytes_reserved += num_bytes;
3823         }
3824
3825         if (block_rsv->reserved >= block_rsv->size) {
3826                 num_bytes = block_rsv->reserved - block_rsv->size;
3827                 sinfo->bytes_reserved -= num_bytes;
3828                 sinfo->reservation_progress++;
3829                 block_rsv->reserved = block_rsv->size;
3830                 block_rsv->full = 1;
3831         }
3832
3833         spin_unlock(&sinfo->lock);
3834         spin_unlock(&block_rsv->lock);
3835 }
3836
3837 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
3838 {
3839         struct btrfs_space_info *space_info;
3840
3841         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3842         fs_info->chunk_block_rsv.space_info = space_info;
3843         fs_info->chunk_block_rsv.priority = 10;
3844
3845         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3846         fs_info->global_block_rsv.space_info = space_info;
3847         fs_info->global_block_rsv.priority = 10;
3848         fs_info->global_block_rsv.refill_used = 1;
3849         fs_info->delalloc_block_rsv.space_info = space_info;
3850         fs_info->trans_block_rsv.space_info = space_info;
3851         fs_info->empty_block_rsv.space_info = space_info;
3852         fs_info->empty_block_rsv.priority = 10;
3853
3854         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
3855         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
3856         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
3857         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
3858         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
3859
3860         btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
3861
3862         btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
3863
3864         update_global_block_rsv(fs_info);
3865 }
3866
3867 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
3868 {
3869         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
3870         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
3871         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
3872         WARN_ON(fs_info->trans_block_rsv.size > 0);
3873         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
3874         WARN_ON(fs_info->chunk_block_rsv.size > 0);
3875         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
3876 }
3877
3878 int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans,
3879                                     struct btrfs_root *root,
3880                                     struct btrfs_block_rsv *rsv)
3881 {
3882         struct btrfs_block_rsv *trans_rsv = &root->fs_info->trans_block_rsv;
3883         u64 num_bytes;
3884         int ret;
3885
3886         /*
3887          * Truncate should be freeing data, but give us 2 items just in case it
3888          * needs to use some space.  We may want to be smarter about this in the
3889          * future.
3890          */
3891         num_bytes = btrfs_calc_trans_metadata_size(root, 2);
3892
3893         /* We already have enough bytes, just return */
3894         if (rsv->reserved >= num_bytes)
3895                 return 0;
3896
3897         num_bytes -= rsv->reserved;
3898
3899         /*
3900          * You should have reserved enough space before hand to do this, so this
3901          * should not fail.
3902          */
3903         ret = block_rsv_migrate_bytes(trans_rsv, rsv, num_bytes);
3904         BUG_ON(ret);
3905
3906         return 0;
3907 }
3908
3909 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
3910                                   struct btrfs_root *root)
3911 {
3912         if (!trans->bytes_reserved)
3913                 return;
3914
3915         BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
3916         btrfs_block_rsv_release(root, trans->block_rsv,
3917                                 trans->bytes_reserved);
3918         trans->bytes_reserved = 0;
3919 }
3920
3921 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
3922                                   struct inode *inode)
3923 {
3924         struct btrfs_root *root = BTRFS_I(inode)->root;
3925         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3926         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
3927
3928         /*
3929          * We need to hold space in order to delete our orphan item once we've
3930          * added it, so this takes the reservation so we can release it later
3931          * when we are truly done with the orphan item.
3932          */
3933         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3934         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3935 }
3936
3937 void btrfs_orphan_release_metadata(struct inode *inode)
3938 {
3939         struct btrfs_root *root = BTRFS_I(inode)->root;
3940         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3941         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
3942 }
3943
3944 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
3945                                 struct btrfs_pending_snapshot *pending)
3946 {
3947         struct btrfs_root *root = pending->root;
3948         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3949         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
3950         /*
3951          * two for root back/forward refs, two for directory entries
3952          * and one for root of the snapshot.
3953          */
3954         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3955         dst_rsv->space_info = src_rsv->space_info;
3956         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3957 }
3958
3959 static unsigned drop_outstanding_extent(struct inode *inode)
3960 {
3961         unsigned dropped_extents = 0;
3962
3963         spin_lock(&BTRFS_I(inode)->lock);
3964         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
3965         BTRFS_I(inode)->outstanding_extents--;
3966
3967         /*
3968          * If we have more or the same amount of outsanding extents than we have
3969          * reserved then we need to leave the reserved extents count alone.
3970          */
3971         if (BTRFS_I(inode)->outstanding_extents >=
3972             BTRFS_I(inode)->reserved_extents)
3973                 goto out;
3974
3975         dropped_extents = BTRFS_I(inode)->reserved_extents -
3976                 BTRFS_I(inode)->outstanding_extents;
3977         BTRFS_I(inode)->reserved_extents -= dropped_extents;
3978 out:
3979         spin_unlock(&BTRFS_I(inode)->lock);
3980         return dropped_extents;
3981 }
3982
3983 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
3984 {
3985         return num_bytes >>= 3;
3986 }
3987
3988 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
3989 {
3990         struct btrfs_root *root = BTRFS_I(inode)->root;
3991         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
3992         u64 to_reserve = 0;
3993         unsigned nr_extents = 0;
3994         int ret;
3995
3996         if (btrfs_transaction_in_commit(root->fs_info))
3997                 schedule_timeout(1);
3998
3999         num_bytes = ALIGN(num_bytes, root->sectorsize);
4000
4001         spin_lock(&BTRFS_I(inode)->lock);
4002         BTRFS_I(inode)->outstanding_extents++;
4003
4004         if (BTRFS_I(inode)->outstanding_extents >
4005             BTRFS_I(inode)->reserved_extents) {
4006                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4007                         BTRFS_I(inode)->reserved_extents;
4008                 BTRFS_I(inode)->reserved_extents += nr_extents;
4009
4010                 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4011         }
4012         spin_unlock(&BTRFS_I(inode)->lock);
4013
4014         to_reserve += calc_csum_metadata_size(inode, num_bytes);
4015         ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1);
4016         if (ret) {
4017                 unsigned dropped;
4018                 /*
4019                  * We don't need the return value since our reservation failed,
4020                  * we just need to clean up our counter.
4021                  */
4022                 dropped = drop_outstanding_extent(inode);
4023                 WARN_ON(dropped > 1);
4024                 return ret;
4025         }
4026
4027         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4028
4029         return 0;
4030 }
4031
4032 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4033 {
4034         struct btrfs_root *root = BTRFS_I(inode)->root;
4035         u64 to_free = 0;
4036         unsigned dropped;
4037
4038         num_bytes = ALIGN(num_bytes, root->sectorsize);
4039         dropped = drop_outstanding_extent(inode);
4040
4041         to_free = calc_csum_metadata_size(inode, num_bytes);
4042         if (dropped > 0)
4043                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4044
4045         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4046                                 to_free);
4047 }
4048
4049 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4050 {
4051         int ret;
4052
4053         ret = btrfs_check_data_free_space(inode, num_bytes);
4054         if (ret)
4055                 return ret;
4056
4057         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4058         if (ret) {
4059                 btrfs_free_reserved_data_space(inode, num_bytes);
4060                 return ret;
4061         }
4062
4063         return 0;
4064 }
4065
4066 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4067 {
4068         btrfs_delalloc_release_metadata(inode, num_bytes);
4069         btrfs_free_reserved_data_space(inode, num_bytes);
4070 }
4071
4072 static int update_block_group(struct btrfs_trans_handle *trans,
4073                               struct btrfs_root *root,
4074                               u64 bytenr, u64 num_bytes, int alloc)
4075 {
4076         struct btrfs_block_group_cache *cache = NULL;
4077         struct btrfs_fs_info *info = root->fs_info;
4078         u64 total = num_bytes;
4079         u64 old_val;
4080         u64 byte_in_group;
4081         int factor;
4082
4083         /* block accounting for super block */
4084         spin_lock(&info->delalloc_lock);
4085         old_val = btrfs_super_bytes_used(&info->super_copy);
4086         if (alloc)
4087                 old_val += num_bytes;
4088         else
4089                 old_val -= num_bytes;
4090         btrfs_set_super_bytes_used(&info->super_copy, old_val);
4091         spin_unlock(&info->delalloc_lock);
4092
4093         while (total) {
4094                 cache = btrfs_lookup_block_group(info, bytenr);
4095                 if (!cache)
4096                         return -1;
4097                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4098                                     BTRFS_BLOCK_GROUP_RAID1 |
4099                                     BTRFS_BLOCK_GROUP_RAID10))
4100                         factor = 2;
4101                 else
4102                         factor = 1;
4103                 /*
4104                  * If this block group has free space cache written out, we
4105                  * need to make sure to load it if we are removing space.  This
4106                  * is because we need the unpinning stage to actually add the
4107                  * space back to the block group, otherwise we will leak space.
4108                  */
4109                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4110                         cache_block_group(cache, trans, NULL, 1);
4111
4112                 byte_in_group = bytenr - cache->key.objectid;
4113                 WARN_ON(byte_in_group > cache->key.offset);
4114
4115                 spin_lock(&cache->space_info->lock);
4116                 spin_lock(&cache->lock);
4117
4118                 if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
4119                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4120                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4121
4122                 cache->dirty = 1;
4123                 old_val = btrfs_block_group_used(&cache->item);
4124                 num_bytes = min(total, cache->key.offset - byte_in_group);
4125                 if (alloc) {
4126                         old_val += num_bytes;
4127                         btrfs_set_block_group_used(&cache->item, old_val);
4128                         cache->reserved -= num_bytes;
4129                         cache->space_info->bytes_reserved -= num_bytes;
4130                         cache->space_info->reservation_progress++;
4131                         cache->space_info->bytes_used += num_bytes;
4132                         cache->space_info->disk_used += num_bytes * factor;
4133                         spin_unlock(&cache->lock);
4134                         spin_unlock(&cache->space_info->lock);
4135                 } else {
4136                         old_val -= num_bytes;
4137                         btrfs_set_block_group_used(&cache->item, old_val);
4138                         cache->pinned += num_bytes;
4139                         cache->space_info->bytes_pinned += num_bytes;
4140                         cache->space_info->bytes_used -= num_bytes;
4141                         cache->space_info->disk_used -= num_bytes * factor;
4142                         spin_unlock(&cache->lock);
4143                         spin_unlock(&cache->space_info->lock);
4144
4145                         set_extent_dirty(info->pinned_extents,
4146                                          bytenr, bytenr + num_bytes - 1,
4147                                          GFP_NOFS | __GFP_NOFAIL);
4148                 }
4149                 btrfs_put_block_group(cache);
4150                 total -= num_bytes;
4151                 bytenr += num_bytes;
4152         }
4153         return 0;
4154 }
4155
4156 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4157 {
4158         struct btrfs_block_group_cache *cache;
4159         u64 bytenr;
4160
4161         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4162         if (!cache)
4163                 return 0;
4164
4165         bytenr = cache->key.objectid;
4166         btrfs_put_block_group(cache);
4167
4168         return bytenr;
4169 }
4170
4171 static int pin_down_extent(struct btrfs_root *root,
4172                            struct btrfs_block_group_cache *cache,
4173                            u64 bytenr, u64 num_bytes, int reserved)
4174 {
4175         spin_lock(&cache->space_info->lock);
4176         spin_lock(&cache->lock);
4177         cache->pinned += num_bytes;
4178         cache->space_info->bytes_pinned += num_bytes;
4179         if (reserved) {
4180                 cache->reserved -= num_bytes;
4181                 cache->space_info->bytes_reserved -= num_bytes;
4182                 cache->space_info->reservation_progress++;
4183         }
4184         spin_unlock(&cache->lock);
4185         spin_unlock(&cache->space_info->lock);
4186
4187         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4188                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4189         return 0;
4190 }
4191
4192 /*
4193  * this function must be called within transaction
4194  */
4195 int btrfs_pin_extent(struct btrfs_root *root,
4196                      u64 bytenr, u64 num_bytes, int reserved)
4197 {
4198         struct btrfs_block_group_cache *cache;
4199
4200         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4201         BUG_ON(!cache);
4202
4203         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4204
4205         btrfs_put_block_group(cache);
4206         return 0;
4207 }
4208
4209 /*
4210  * update size of reserved extents. this function may return -EAGAIN
4211  * if 'reserve' is true or 'sinfo' is false.
4212  */
4213 int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4214                                 u64 num_bytes, int reserve, int sinfo)
4215 {
4216         int ret = 0;
4217         if (sinfo) {
4218                 struct btrfs_space_info *space_info = cache->space_info;
4219                 spin_lock(&space_info->lock);
4220                 spin_lock(&cache->lock);
4221                 if (reserve) {
4222                         if (cache->ro) {
4223                                 ret = -EAGAIN;
4224                         } else {
4225                                 cache->reserved += num_bytes;
4226                                 space_info->bytes_reserved += num_bytes;
4227                         }
4228                 } else {
4229                         if (cache->ro)
4230                                 space_info->bytes_readonly += num_bytes;
4231                         cache->reserved -= num_bytes;
4232                         space_info->bytes_reserved -= num_bytes;
4233                         space_info->reservation_progress++;
4234                 }
4235                 spin_unlock(&cache->lock);
4236                 spin_unlock(&space_info->lock);
4237         } else {
4238                 spin_lock(&cache->lock);
4239                 if (cache->ro) {
4240                         ret = -EAGAIN;
4241                 } else {
4242                         if (reserve)
4243                                 cache->reserved += num_bytes;
4244                         else
4245                                 cache->reserved -= num_bytes;
4246                 }
4247                 spin_unlock(&cache->lock);
4248         }
4249         return ret;
4250 }
4251
4252 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4253                                 struct btrfs_root *root)
4254 {
4255         struct btrfs_fs_info *fs_info = root->fs_info;
4256         struct btrfs_caching_control *next;
4257         struct btrfs_caching_control *caching_ctl;
4258         struct btrfs_block_group_cache *cache;
4259
4260         down_write(&fs_info->extent_commit_sem);
4261
4262         list_for_each_entry_safe(caching_ctl, next,
4263                                  &fs_info->caching_block_groups, list) {
4264                 cache = caching_ctl->block_group;
4265                 if (block_group_cache_done(cache)) {
4266                         cache->last_byte_to_unpin = (u64)-1;
4267                         list_del_init(&caching_ctl->list);
4268                         put_caching_control(caching_ctl);
4269                 } else {
4270                         cache->last_byte_to_unpin = caching_ctl->progress;
4271                 }
4272         }
4273
4274         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4275                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4276         else
4277                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4278
4279         up_write(&fs_info->extent_commit_sem);
4280
4281         update_global_block_rsv(fs_info);
4282         return 0;
4283 }
4284
4285 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4286 {
4287         struct btrfs_fs_info *fs_info = root->fs_info;
4288         struct btrfs_block_group_cache *cache = NULL;
4289         u64 len;
4290
4291         while (start <= end) {
4292                 if (!cache ||
4293                     start >= cache->key.objectid + cache->key.offset) {
4294                         if (cache)
4295                                 btrfs_put_block_group(cache);
4296                         cache = btrfs_lookup_block_group(fs_info, start);
4297                         BUG_ON(!cache);
4298                 }
4299
4300                 len = cache->key.objectid + cache->key.offset - start;
4301                 len = min(len, end + 1 - start);
4302
4303                 if (start < cache->last_byte_to_unpin) {
4304                         len = min(len, cache->last_byte_to_unpin - start);
4305                         btrfs_add_free_space(cache, start, len);
4306                 }
4307
4308                 start += len;
4309
4310                 spin_lock(&cache->space_info->lock);
4311                 spin_lock(&cache->lock);
4312                 cache->pinned -= len;
4313                 cache->space_info->bytes_pinned -= len;
4314                 if (cache->ro) {
4315                         cache->space_info->bytes_readonly += len;
4316                 } else if (cache->reserved_pinned > 0) {
4317                         len = min(len, cache->reserved_pinned);
4318                         cache->reserved_pinned -= len;
4319                         cache->space_info->bytes_reserved += len;
4320                 }
4321                 spin_unlock(&cache->lock);
4322                 spin_unlock(&cache->space_info->lock);
4323         }
4324
4325         if (cache)
4326                 btrfs_put_block_group(cache);
4327         return 0;
4328 }
4329
4330 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4331                                struct btrfs_root *root)
4332 {
4333         struct btrfs_fs_info *fs_info = root->fs_info;
4334         struct extent_io_tree *unpin;
4335         struct btrfs_block_rsv *block_rsv;
4336         struct btrfs_block_rsv *next_rsv;
4337         u64 start;
4338         u64 end;
4339         int idx;
4340         int ret;
4341
4342         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4343                 unpin = &fs_info->freed_extents[1];
4344         else
4345                 unpin = &fs_info->freed_extents[0];
4346
4347         while (1) {
4348                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4349                                             EXTENT_DIRTY);
4350                 if (ret)
4351                         break;
4352
4353                 if (btrfs_test_opt(root, DISCARD))
4354                         ret = btrfs_discard_extent(root, start,
4355                                                    end + 1 - start, NULL);
4356
4357                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4358                 unpin_extent_range(root, start, end);
4359                 cond_resched();
4360         }
4361
4362         mutex_lock(&fs_info->durable_block_rsv_mutex);
4363         list_for_each_entry_safe(block_rsv, next_rsv,
4364                                  &fs_info->durable_block_rsv_list, list) {
4365
4366                 idx = trans->transid & 0x1;
4367                 if (block_rsv->freed[idx] > 0) {
4368                         block_rsv_add_bytes(block_rsv,
4369                                             block_rsv->freed[idx], 0);
4370                         block_rsv->freed[idx] = 0;
4371                 }
4372                 if (atomic_read(&block_rsv->usage) == 0) {
4373                         btrfs_block_rsv_release(root, block_rsv, (u64)-1);
4374
4375                         if (block_rsv->freed[0] == 0 &&
4376                             block_rsv->freed[1] == 0) {
4377                                 list_del_init(&block_rsv->list);
4378                                 kfree(block_rsv);
4379                         }
4380                 } else {
4381                         btrfs_block_rsv_release(root, block_rsv, 0);
4382                 }
4383         }
4384         mutex_unlock(&fs_info->durable_block_rsv_mutex);
4385
4386         return 0;
4387 }
4388
4389 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4390                                 struct btrfs_root *root,
4391                                 u64 bytenr, u64 num_bytes, u64 parent,
4392                                 u64 root_objectid, u64 owner_objectid,
4393                                 u64 owner_offset, int refs_to_drop,
4394                                 struct btrfs_delayed_extent_op *extent_op)
4395 {
4396         struct btrfs_key key;
4397         struct btrfs_path *path;
4398         struct btrfs_fs_info *info = root->fs_info;
4399         struct btrfs_root *extent_root = info->extent_root;
4400         struct extent_buffer *leaf;
4401         struct btrfs_extent_item *ei;
4402         struct btrfs_extent_inline_ref *iref;
4403         int ret;
4404         int is_data;
4405         int extent_slot = 0;
4406         int found_extent = 0;
4407         int num_to_del = 1;
4408         u32 item_size;
4409         u64 refs;
4410
4411         path = btrfs_alloc_path();
4412         if (!path)
4413                 return -ENOMEM;
4414
4415         path->reada = 1;
4416         path->leave_spinning = 1;
4417
4418         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4419         BUG_ON(!is_data && refs_to_drop != 1);
4420
4421         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4422                                     bytenr, num_bytes, parent,
4423                                     root_objectid, owner_objectid,
4424                                     owner_offset);
4425         if (ret == 0) {
4426                 extent_slot = path->slots[0];
4427                 while (extent_slot >= 0) {
4428                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4429                                               extent_slot);
4430                         if (key.objectid != bytenr)
4431                                 break;
4432                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4433                             key.offset == num_bytes) {
4434                                 found_extent = 1;
4435                                 break;
4436                         }
4437                         if (path->slots[0] - extent_slot > 5)
4438                                 break;
4439                         extent_slot--;
4440                 }
4441 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4442                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4443                 if (found_extent && item_size < sizeof(*ei))
4444                         found_extent = 0;
4445 #endif
4446                 if (!found_extent) {
4447                         BUG_ON(iref);
4448                         ret = remove_extent_backref(trans, extent_root, path,
4449                                                     NULL, refs_to_drop,
4450                                                     is_data);
4451                         BUG_ON(ret);
4452                         btrfs_release_path(path);
4453                         path->leave_spinning = 1;
4454
4455                         key.objectid = bytenr;
4456                         key.type = BTRFS_EXTENT_ITEM_KEY;
4457                         key.offset = num_bytes;
4458
4459                         ret = btrfs_search_slot(trans, extent_root,
4460                                                 &key, path, -1, 1);
4461                         if (ret) {
4462                                 printk(KERN_ERR "umm, got %d back from search"
4463                                        ", was looking for %llu\n", ret,
4464                                        (unsigned long long)bytenr);
4465                                 if (ret > 0)
4466                                         btrfs_print_leaf(extent_root,
4467                                                          path->nodes[0]);
4468                         }
4469                         BUG_ON(ret);
4470                         extent_slot = path->slots[0];
4471                 }
4472         } else {
4473                 btrfs_print_leaf(extent_root, path->nodes[0]);
4474                 WARN_ON(1);
4475                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4476                        "parent %llu root %llu  owner %llu offset %llu\n",
4477                        (unsigned long long)bytenr,
4478                        (unsigned long long)parent,
4479                        (unsigned long long)root_objectid,
4480                        (unsigned long long)owner_objectid,
4481                        (unsigned long long)owner_offset);
4482         }
4483
4484         leaf = path->nodes[0];
4485         item_size = btrfs_item_size_nr(leaf, extent_slot);
4486 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4487         if (item_size < sizeof(*ei)) {
4488                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4489                 ret = convert_extent_item_v0(trans, extent_root, path,
4490                                              owner_objectid, 0);
4491                 BUG_ON(ret < 0);
4492
4493                 btrfs_release_path(path);
4494                 path->leave_spinning = 1;
4495
4496                 key.objectid = bytenr;
4497                 key.type = BTRFS_EXTENT_ITEM_KEY;
4498                 key.offset = num_bytes;
4499
4500                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4501                                         -1, 1);
4502                 if (ret) {
4503                         printk(KERN_ERR "umm, got %d back from search"
4504                                ", was looking for %llu\n", ret,
4505                                (unsigned long long)bytenr);
4506                         btrfs_print_leaf(extent_root, path->nodes[0]);
4507                 }
4508                 BUG_ON(ret);
4509                 extent_slot = path->slots[0];
4510                 leaf = path->nodes[0];
4511                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4512         }
4513 #endif
4514         BUG_ON(item_size < sizeof(*ei));
4515         ei = btrfs_item_ptr(leaf, extent_slot,
4516                             struct btrfs_extent_item);
4517         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4518                 struct btrfs_tree_block_info *bi;
4519                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4520                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4521                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4522         }
4523
4524         refs = btrfs_extent_refs(leaf, ei);
4525         BUG_ON(refs < refs_to_drop);
4526         refs -= refs_to_drop;
4527
4528         if (refs > 0) {
4529                 if (extent_op)
4530                         __run_delayed_extent_op(extent_op, leaf, ei);
4531                 /*
4532                  * In the case of inline back ref, reference count will
4533                  * be updated by remove_extent_backref
4534                  */
4535                 if (iref) {
4536                         BUG_ON(!found_extent);
4537                 } else {
4538                         btrfs_set_extent_refs(leaf, ei, refs);
4539                         btrfs_mark_buffer_dirty(leaf);
4540                 }
4541                 if (found_extent) {
4542                         ret = remove_extent_backref(trans, extent_root, path,
4543                                                     iref, refs_to_drop,
4544                                                     is_data);
4545                         BUG_ON(ret);
4546                 }
4547         } else {
4548                 if (found_extent) {
4549                         BUG_ON(is_data && refs_to_drop !=
4550                                extent_data_ref_count(root, path, iref));
4551                         if (iref) {
4552                                 BUG_ON(path->slots[0] != extent_slot);
4553                         } else {
4554                                 BUG_ON(path->slots[0] != extent_slot + 1);
4555                                 path->slots[0] = extent_slot;
4556                                 num_to_del = 2;
4557                         }
4558                 }
4559
4560                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4561                                       num_to_del);
4562                 BUG_ON(ret);
4563                 btrfs_release_path(path);
4564
4565                 if (is_data) {
4566                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4567                         BUG_ON(ret);
4568                 } else {
4569                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4570                              bytenr >> PAGE_CACHE_SHIFT,
4571                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4572                 }
4573
4574                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4575                 BUG_ON(ret);
4576         }
4577         btrfs_free_path(path);
4578         return ret;
4579 }
4580
4581 /*
4582  * when we free an block, it is possible (and likely) that we free the last
4583  * delayed ref for that extent as well.  This searches the delayed ref tree for
4584  * a given extent, and if there are no other delayed refs to be processed, it
4585  * removes it from the tree.
4586  */
4587 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4588                                       struct btrfs_root *root, u64 bytenr)
4589 {
4590         struct btrfs_delayed_ref_head *head;
4591         struct btrfs_delayed_ref_root *delayed_refs;
4592         struct btrfs_delayed_ref_node *ref;
4593         struct rb_node *node;
4594         int ret = 0;
4595
4596         delayed_refs = &trans->transaction->delayed_refs;
4597         spin_lock(&delayed_refs->lock);
4598         head = btrfs_find_delayed_ref_head(trans, bytenr);
4599         if (!head)
4600                 goto out;
4601
4602         node = rb_prev(&head->node.rb_node);
4603         if (!node)
4604                 goto out;
4605
4606         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4607
4608         /* there are still entries for this ref, we can't drop it */
4609         if (ref->bytenr == bytenr)
4610                 goto out;
4611
4612         if (head->extent_op) {
4613                 if (!head->must_insert_reserved)
4614                         goto out;
4615                 kfree(head->extent_op);
4616                 head->extent_op = NULL;
4617         }
4618
4619         /*
4620          * waiting for the lock here would deadlock.  If someone else has it
4621          * locked they are already in the process of dropping it anyway
4622          */
4623         if (!mutex_trylock(&head->mutex))
4624                 goto out;
4625
4626         /*
4627          * at this point we have a head with no other entries.  Go
4628          * ahead and process it.
4629          */
4630         head->node.in_tree = 0;
4631         rb_erase(&head->node.rb_node, &delayed_refs->root);
4632
4633         delayed_refs->num_entries--;
4634
4635         /*
4636          * we don't take a ref on the node because we're removing it from the
4637          * tree, so we just steal the ref the tree was holding.
4638          */
4639         delayed_refs->num_heads--;
4640         if (list_empty(&head->cluster))
4641                 delayed_refs->num_heads_ready--;
4642
4643         list_del_init(&head->cluster);
4644         spin_unlock(&delayed_refs->lock);
4645
4646         BUG_ON(head->extent_op);
4647         if (head->must_insert_reserved)
4648                 ret = 1;
4649
4650         mutex_unlock(&head->mutex);
4651         btrfs_put_delayed_ref(&head->node);
4652         return ret;
4653 out:
4654         spin_unlock(&delayed_refs->lock);
4655         return 0;
4656 }
4657
4658 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4659                            struct btrfs_root *root,
4660                            struct extent_buffer *buf,
4661                            u64 parent, int last_ref)
4662 {
4663         struct btrfs_block_rsv *block_rsv;
4664         struct btrfs_block_group_cache *cache = NULL;
4665         int ret;
4666
4667         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4668                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4669                                                 parent, root->root_key.objectid,
4670                                                 btrfs_header_level(buf),
4671                                                 BTRFS_DROP_DELAYED_REF, NULL);
4672                 BUG_ON(ret);
4673         }
4674
4675         if (!last_ref)
4676                 return;
4677
4678         block_rsv = get_block_rsv(trans, root);
4679         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4680         if (block_rsv->space_info != cache->space_info)
4681                 goto out;
4682
4683         if (btrfs_header_generation(buf) == trans->transid) {
4684                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4685                         ret = check_ref_cleanup(trans, root, buf->start);
4686                         if (!ret)
4687                                 goto pin;
4688                 }
4689
4690                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4691                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4692                         goto pin;
4693                 }
4694
4695                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4696
4697                 btrfs_add_free_space(cache, buf->start, buf->len);
4698                 ret = btrfs_update_reserved_bytes(cache, buf->len, 0, 0);
4699                 if (ret == -EAGAIN) {
4700                         /* block group became read-only */
4701                         btrfs_update_reserved_bytes(cache, buf->len, 0, 1);
4702                         goto out;
4703                 }
4704
4705                 ret = 1;
4706                 spin_lock(&block_rsv->lock);
4707                 if (block_rsv->reserved < block_rsv->size) {
4708                         block_rsv->reserved += buf->len;
4709                         ret = 0;
4710                 }
4711                 spin_unlock(&block_rsv->lock);
4712
4713                 if (ret) {
4714                         spin_lock(&cache->space_info->lock);
4715                         cache->space_info->bytes_reserved -= buf->len;
4716                         cache->space_info->reservation_progress++;
4717                         spin_unlock(&cache->space_info->lock);
4718                 }
4719                 goto out;
4720         }
4721 pin:
4722         if (block_rsv->durable && !cache->ro) {
4723                 ret = 0;
4724                 spin_lock(&cache->lock);
4725                 if (!cache->ro) {
4726                         cache->reserved_pinned += buf->len;
4727                         ret = 1;
4728                 }
4729                 spin_unlock(&cache->lock);
4730
4731                 if (ret) {
4732                         spin_lock(&block_rsv->lock);
4733                         block_rsv->freed[trans->transid & 0x1] += buf->len;
4734                         spin_unlock(&block_rsv->lock);
4735                 }
4736         }
4737 out:
4738         /*
4739          * Deleting the buffer, clear the corrupt flag since it doesn't matter
4740          * anymore.
4741          */
4742         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
4743         btrfs_put_block_group(cache);
4744 }
4745
4746 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4747                       struct btrfs_root *root,
4748                       u64 bytenr, u64 num_bytes, u64 parent,
4749                       u64 root_objectid, u64 owner, u64 offset)
4750 {
4751         int ret;
4752
4753         /*
4754          * tree log blocks never actually go into the extent allocation
4755          * tree, just update pinning info and exit early.
4756          */
4757         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4758                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4759                 /* unlocks the pinned mutex */
4760                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4761                 ret = 0;
4762         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4763                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4764                                         parent, root_objectid, (int)owner,
4765                                         BTRFS_DROP_DELAYED_REF, NULL);
4766                 BUG_ON(ret);
4767         } else {
4768                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4769                                         parent, root_objectid, owner,
4770                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4771                 BUG_ON(ret);
4772         }
4773         return ret;
4774 }
4775
4776 static u64 stripe_align(struct btrfs_root *root, u64 val)
4777 {
4778         u64 mask = ((u64)root->stripesize - 1);
4779         u64 ret = (val + mask) & ~mask;
4780         return ret;
4781 }
4782
4783 /*
4784  * when we wait for progress in the block group caching, its because
4785  * our allocation attempt failed at least once.  So, we must sleep
4786  * and let some progress happen before we try again.
4787  *
4788  * This function will sleep at least once waiting for new free space to
4789  * show up, and then it will check the block group free space numbers
4790  * for our min num_bytes.  Another option is to have it go ahead
4791  * and look in the rbtree for a free extent of a given size, but this
4792  * is a good start.
4793  */
4794 static noinline int
4795 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4796                                 u64 num_bytes)
4797 {
4798         struct btrfs_caching_control *caching_ctl;
4799         DEFINE_WAIT(wait);
4800
4801         caching_ctl = get_caching_control(cache);
4802         if (!caching_ctl)
4803                 return 0;
4804
4805         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4806                    (cache->free_space_ctl->free_space >= num_bytes));
4807
4808         put_caching_control(caching_ctl);
4809         return 0;
4810 }
4811
4812 static noinline int
4813 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4814 {
4815         struct btrfs_caching_control *caching_ctl;
4816         DEFINE_WAIT(wait);
4817
4818         caching_ctl = get_caching_control(cache);
4819         if (!caching_ctl)
4820                 return 0;
4821
4822         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4823
4824         put_caching_control(caching_ctl);
4825         return 0;
4826 }
4827
4828 static int get_block_group_index(struct btrfs_block_group_cache *cache)
4829 {
4830         int index;
4831         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
4832                 index = 0;
4833         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
4834                 index = 1;
4835         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
4836                 index = 2;
4837         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
4838                 index = 3;
4839         else
4840                 index = 4;
4841         return index;
4842 }
4843
4844 enum btrfs_loop_type {
4845         LOOP_FIND_IDEAL = 0,
4846         LOOP_CACHING_NOWAIT = 1,
4847         LOOP_CACHING_WAIT = 2,
4848         LOOP_ALLOC_CHUNK = 3,
4849         LOOP_NO_EMPTY_SIZE = 4,
4850 };
4851
4852 /*
4853  * walks the btree of allocated extents and find a hole of a given size.
4854  * The key ins is changed to record the hole:
4855  * ins->objectid == block start
4856  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4857  * ins->offset == number of blocks
4858  * Any available blocks before search_start are skipped.
4859  */
4860 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4861                                      struct btrfs_root *orig_root,
4862                                      u64 num_bytes, u64 empty_size,
4863                                      u64 search_start, u64 search_end,
4864                                      u64 hint_byte, struct btrfs_key *ins,
4865                                      u64 data)
4866 {
4867         int ret = 0;
4868         struct btrfs_root *root = orig_root->fs_info->extent_root;
4869         struct btrfs_free_cluster *last_ptr = NULL;
4870         struct btrfs_block_group_cache *block_group = NULL;
4871         int empty_cluster = 2 * 1024 * 1024;
4872         int allowed_chunk_alloc = 0;
4873         int done_chunk_alloc = 0;
4874         struct btrfs_space_info *space_info;
4875         int last_ptr_loop = 0;
4876         int loop = 0;
4877         int index = 0;
4878         bool found_uncached_bg = false;
4879         bool failed_cluster_refill = false;
4880         bool failed_alloc = false;
4881         bool use_cluster = true;
4882         u64 ideal_cache_percent = 0;
4883         u64 ideal_cache_offset = 0;
4884
4885         WARN_ON(num_bytes < root->sectorsize);
4886         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4887         ins->objectid = 0;
4888         ins->offset = 0;
4889
4890         space_info = __find_space_info(root->fs_info, data);
4891         if (!space_info) {
4892                 printk(KERN_ERR "No space info for %llu\n", data);
4893                 return -ENOSPC;
4894         }
4895
4896         /*
4897          * If the space info is for both data and metadata it means we have a
4898          * small filesystem and we can't use the clustering stuff.
4899          */
4900         if (btrfs_mixed_space_info(space_info))
4901                 use_cluster = false;
4902
4903         if (orig_root->ref_cows || empty_size)
4904                 allowed_chunk_alloc = 1;
4905
4906         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
4907                 last_ptr = &root->fs_info->meta_alloc_cluster;
4908                 if (!btrfs_test_opt(root, SSD))
4909                         empty_cluster = 64 * 1024;
4910         }
4911
4912         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
4913             btrfs_test_opt(root, SSD)) {
4914                 last_ptr = &root->fs_info->data_alloc_cluster;
4915         }
4916
4917         if (last_ptr) {
4918                 spin_lock(&last_ptr->lock);
4919                 if (last_ptr->block_group)
4920                         hint_byte = last_ptr->window_start;
4921                 spin_unlock(&last_ptr->lock);
4922         }
4923
4924         search_start = max(search_start, first_logical_byte(root, 0));
4925         search_start = max(search_start, hint_byte);
4926
4927         if (!last_ptr)
4928                 empty_cluster = 0;
4929
4930         if (search_start == hint_byte) {
4931 ideal_cache:
4932                 block_group = btrfs_lookup_block_group(root->fs_info,
4933                                                        search_start);
4934                 /*
4935                  * we don't want to use the block group if it doesn't match our
4936                  * allocation bits, or if its not cached.
4937                  *
4938                  * However if we are re-searching with an ideal block group
4939                  * picked out then we don't care that the block group is cached.
4940                  */
4941                 if (block_group && block_group_bits(block_group, data) &&
4942                     (block_group->cached != BTRFS_CACHE_NO ||
4943                      search_start == ideal_cache_offset)) {
4944                         down_read(&space_info->groups_sem);
4945                         if (list_empty(&block_group->list) ||
4946                             block_group->ro) {
4947                                 /*
4948                                  * someone is removing this block group,
4949                                  * we can't jump into the have_block_group
4950                                  * target because our list pointers are not
4951                                  * valid
4952                                  */
4953                                 btrfs_put_block_group(block_group);
4954                                 up_read(&space_info->groups_sem);
4955                         } else {
4956                                 index = get_block_group_index(block_group);
4957                                 goto have_block_group;
4958                         }
4959                 } else if (block_group) {
4960                         btrfs_put_block_group(block_group);
4961                 }
4962         }
4963 search:
4964         down_read(&space_info->groups_sem);
4965         list_for_each_entry(block_group, &space_info->block_groups[index],
4966                             list) {
4967                 u64 offset;
4968                 int cached;
4969
4970                 btrfs_get_block_group(block_group);
4971                 search_start = block_group->key.objectid;
4972
4973                 /*
4974                  * this can happen if we end up cycling through all the
4975                  * raid types, but we want to make sure we only allocate
4976                  * for the proper type.
4977                  */
4978                 if (!block_group_bits(block_group, data)) {
4979                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
4980                                 BTRFS_BLOCK_GROUP_RAID1 |
4981                                 BTRFS_BLOCK_GROUP_RAID10;
4982
4983                         /*
4984                          * if they asked for extra copies and this block group
4985                          * doesn't provide them, bail.  This does allow us to
4986                          * fill raid0 from raid1.
4987                          */
4988                         if ((data & extra) && !(block_group->flags & extra))
4989                                 goto loop;
4990                 }
4991
4992 have_block_group:
4993                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4994                         u64 free_percent;
4995
4996                         ret = cache_block_group(block_group, trans,
4997                                                 orig_root, 1);
4998                         if (block_group->cached == BTRFS_CACHE_FINISHED)
4999                                 goto have_block_group;
5000
5001                         free_percent = btrfs_block_group_used(&block_group->item);
5002                         free_percent *= 100;
5003                         free_percent = div64_u64(free_percent,
5004                                                  block_group->key.offset);
5005                         free_percent = 100 - free_percent;
5006                         if (free_percent > ideal_cache_percent &&
5007                             likely(!block_group->ro)) {
5008                                 ideal_cache_offset = block_group->key.objectid;
5009                                 ideal_cache_percent = free_percent;
5010                         }
5011
5012                         /*
5013                          * The caching workers are limited to 2 threads, so we
5014                          * can queue as much work as we care to.
5015                          */
5016                         if (loop > LOOP_FIND_IDEAL) {
5017                                 ret = cache_block_group(block_group, trans,
5018                                                         orig_root, 0);
5019                                 BUG_ON(ret);
5020                         }
5021                         found_uncached_bg = true;
5022
5023                         /*
5024                          * If loop is set for cached only, try the next block
5025                          * group.
5026                          */
5027                         if (loop == LOOP_FIND_IDEAL)
5028                                 goto loop;
5029                 }
5030
5031                 cached = block_group_cache_done(block_group);
5032                 if (unlikely(!cached))
5033                         found_uncached_bg = true;
5034
5035                 if (unlikely(block_group->ro))
5036                         goto loop;
5037
5038                 spin_lock(&block_group->free_space_ctl->tree_lock);
5039                 if (cached &&
5040                     block_group->free_space_ctl->free_space <
5041                     num_bytes + empty_size) {
5042                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5043                         goto loop;
5044                 }
5045                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5046
5047                 /*
5048                  * Ok we want to try and use the cluster allocator, so lets look
5049                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
5050                  * have tried the cluster allocator plenty of times at this
5051                  * point and not have found anything, so we are likely way too
5052                  * fragmented for the clustering stuff to find anything, so lets
5053                  * just skip it and let the allocator find whatever block it can
5054                  * find
5055                  */
5056                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
5057                         /*
5058                          * the refill lock keeps out other
5059                          * people trying to start a new cluster
5060                          */
5061                         spin_lock(&last_ptr->refill_lock);
5062                         if (last_ptr->block_group &&
5063                             (last_ptr->block_group->ro ||
5064                             !block_group_bits(last_ptr->block_group, data))) {
5065                                 offset = 0;
5066                                 goto refill_cluster;
5067                         }
5068
5069                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
5070                                                  num_bytes, search_start);
5071                         if (offset) {
5072                                 /* we have a block, we're done */
5073                                 spin_unlock(&last_ptr->refill_lock);
5074                                 goto checks;
5075                         }
5076
5077                         spin_lock(&last_ptr->lock);
5078                         /*
5079                          * whoops, this cluster doesn't actually point to
5080                          * this block group.  Get a ref on the block
5081                          * group is does point to and try again
5082                          */
5083                         if (!last_ptr_loop && last_ptr->block_group &&
5084                             last_ptr->block_group != block_group &&
5085                             index <=
5086                                  get_block_group_index(last_ptr->block_group)) {
5087
5088                                 btrfs_put_block_group(block_group);
5089                                 block_group = last_ptr->block_group;
5090                                 btrfs_get_block_group(block_group);
5091                                 spin_unlock(&last_ptr->lock);
5092                                 spin_unlock(&last_ptr->refill_lock);
5093
5094                                 last_ptr_loop = 1;
5095                                 search_start = block_group->key.objectid;
5096                                 /*
5097                                  * we know this block group is properly
5098                                  * in the list because
5099                                  * btrfs_remove_block_group, drops the
5100                                  * cluster before it removes the block
5101                                  * group from the list
5102                                  */
5103                                 goto have_block_group;
5104                         }
5105                         spin_unlock(&last_ptr->lock);
5106 refill_cluster:
5107                         /*
5108                          * this cluster didn't work out, free it and
5109                          * start over
5110                          */
5111                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5112
5113                         last_ptr_loop = 0;
5114
5115                         /* allocate a cluster in this block group */
5116                         ret = btrfs_find_space_cluster(trans, root,
5117                                                block_group, last_ptr,
5118                                                offset, num_bytes,
5119                                                empty_cluster + empty_size);
5120                         if (ret == 0) {
5121                                 /*
5122                                  * now pull our allocation out of this
5123                                  * cluster
5124                                  */
5125                                 offset = btrfs_alloc_from_cluster(block_group,
5126                                                   last_ptr, num_bytes,
5127                                                   search_start);
5128                                 if (offset) {
5129                                         /* we found one, proceed */
5130                                         spin_unlock(&last_ptr->refill_lock);
5131                                         goto checks;
5132                                 }
5133                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5134                                    && !failed_cluster_refill) {
5135                                 spin_unlock(&last_ptr->refill_lock);
5136
5137                                 failed_cluster_refill = true;
5138                                 wait_block_group_cache_progress(block_group,
5139                                        num_bytes + empty_cluster + empty_size);
5140                                 goto have_block_group;
5141                         }
5142
5143                         /*
5144                          * at this point we either didn't find a cluster
5145                          * or we weren't able to allocate a block from our
5146                          * cluster.  Free the cluster we've been trying
5147                          * to use, and go to the next block group
5148                          */
5149                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5150                         spin_unlock(&last_ptr->refill_lock);
5151                         goto loop;
5152                 }
5153
5154                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5155                                                     num_bytes, empty_size);
5156                 /*
5157                  * If we didn't find a chunk, and we haven't failed on this
5158                  * block group before, and this block group is in the middle of
5159                  * caching and we are ok with waiting, then go ahead and wait
5160                  * for progress to be made, and set failed_alloc to true.
5161                  *
5162                  * If failed_alloc is true then we've already waited on this
5163                  * block group once and should move on to the next block group.
5164                  */
5165                 if (!offset && !failed_alloc && !cached &&
5166                     loop > LOOP_CACHING_NOWAIT) {
5167                         wait_block_group_cache_progress(block_group,
5168                                                 num_bytes + empty_size);
5169                         failed_alloc = true;
5170                         goto have_block_group;
5171                 } else if (!offset) {
5172                         goto loop;
5173                 }
5174 checks:
5175                 search_start = stripe_align(root, offset);
5176                 /* move on to the next group */
5177                 if (search_start + num_bytes >= search_end) {
5178                         btrfs_add_free_space(block_group, offset, num_bytes);
5179                         goto loop;
5180                 }
5181
5182                 /* move on to the next group */
5183                 if (search_start + num_bytes >
5184                     block_group->key.objectid + block_group->key.offset) {
5185                         btrfs_add_free_space(block_group, offset, num_bytes);
5186                         goto loop;
5187                 }
5188
5189                 ins->objectid = search_start;
5190                 ins->offset = num_bytes;
5191
5192                 if (offset < search_start)
5193                         btrfs_add_free_space(block_group, offset,
5194                                              search_start - offset);
5195                 BUG_ON(offset > search_start);
5196
5197                 ret = btrfs_update_reserved_bytes(block_group, num_bytes, 1,
5198                                             (data & BTRFS_BLOCK_GROUP_DATA));
5199                 if (ret == -EAGAIN) {
5200                         btrfs_add_free_space(block_group, offset, num_bytes);
5201                         goto loop;
5202                 }
5203
5204                 /* we are all good, lets return */
5205                 ins->objectid = search_start;
5206                 ins->offset = num_bytes;
5207
5208                 if (offset < search_start)
5209                         btrfs_add_free_space(block_group, offset,
5210                                              search_start - offset);
5211                 BUG_ON(offset > search_start);
5212                 btrfs_put_block_group(block_group);
5213                 break;
5214 loop:
5215                 failed_cluster_refill = false;
5216                 failed_alloc = false;
5217                 BUG_ON(index != get_block_group_index(block_group));
5218                 btrfs_put_block_group(block_group);
5219         }
5220         up_read(&space_info->groups_sem);
5221
5222         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5223                 goto search;
5224
5225         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5226          *                      for them to make caching progress.  Also
5227          *                      determine the best possible bg to cache
5228          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5229          *                      caching kthreads as we move along
5230          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5231          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5232          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5233          *                      again
5234          */
5235         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5236                 index = 0;
5237                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5238                         found_uncached_bg = false;
5239                         loop++;
5240                         if (!ideal_cache_percent)
5241                                 goto search;
5242
5243                         /*
5244                          * 1 of the following 2 things have happened so far
5245                          *
5246                          * 1) We found an ideal block group for caching that
5247                          * is mostly full and will cache quickly, so we might
5248                          * as well wait for it.
5249                          *
5250                          * 2) We searched for cached only and we didn't find
5251                          * anything, and we didn't start any caching kthreads
5252                          * either, so chances are we will loop through and
5253                          * start a couple caching kthreads, and then come back
5254                          * around and just wait for them.  This will be slower
5255                          * because we will have 2 caching kthreads reading at
5256                          * the same time when we could have just started one
5257                          * and waited for it to get far enough to give us an
5258                          * allocation, so go ahead and go to the wait caching
5259                          * loop.
5260                          */
5261                         loop = LOOP_CACHING_WAIT;
5262                         search_start = ideal_cache_offset;
5263                         ideal_cache_percent = 0;
5264                         goto ideal_cache;
5265                 } else if (loop == LOOP_FIND_IDEAL) {
5266                         /*
5267                          * Didn't find a uncached bg, wait on anything we find
5268                          * next.
5269                          */
5270                         loop = LOOP_CACHING_WAIT;
5271                         goto search;
5272                 }
5273
5274                 loop++;
5275
5276                 if (loop == LOOP_ALLOC_CHUNK) {
5277                        if (allowed_chunk_alloc) {
5278                                 ret = do_chunk_alloc(trans, root, num_bytes +
5279                                                      2 * 1024 * 1024, data,
5280                                                      CHUNK_ALLOC_LIMITED);
5281                                 allowed_chunk_alloc = 0;
5282                                 if (ret == 1)
5283                                         done_chunk_alloc = 1;
5284                         } else if (!done_chunk_alloc &&
5285                                    space_info->force_alloc ==
5286                                    CHUNK_ALLOC_NO_FORCE) {
5287                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5288                         }
5289
5290                        /*
5291                         * We didn't allocate a chunk, go ahead and drop the
5292                         * empty size and loop again.
5293                         */
5294                        if (!done_chunk_alloc)
5295                                loop = LOOP_NO_EMPTY_SIZE;
5296                 }
5297
5298                 if (loop == LOOP_NO_EMPTY_SIZE) {
5299                         empty_size = 0;
5300                         empty_cluster = 0;
5301                 }
5302
5303                 goto search;
5304         } else if (!ins->objectid) {
5305                 ret = -ENOSPC;
5306         } else if (ins->objectid) {
5307                 ret = 0;
5308         }
5309
5310         return ret;
5311 }
5312
5313 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5314                             int dump_block_groups)
5315 {
5316         struct btrfs_block_group_cache *cache;
5317         int index = 0;
5318
5319         spin_lock(&info->lock);
5320         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
5321                (unsigned long long)(info->total_bytes - info->bytes_used -
5322                                     info->bytes_pinned - info->bytes_reserved -
5323                                     info->bytes_readonly),
5324                (info->full) ? "" : "not ");
5325         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5326                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5327                (unsigned long long)info->total_bytes,
5328                (unsigned long long)info->bytes_used,
5329                (unsigned long long)info->bytes_pinned,
5330                (unsigned long long)info->bytes_reserved,
5331                (unsigned long long)info->bytes_may_use,
5332                (unsigned long long)info->bytes_readonly);
5333         spin_unlock(&info->lock);
5334
5335         if (!dump_block_groups)
5336                 return;
5337
5338         down_read(&info->groups_sem);
5339 again:
5340         list_for_each_entry(cache, &info->block_groups[index], list) {
5341                 spin_lock(&cache->lock);
5342                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5343                        "%llu pinned %llu reserved\n",
5344                        (unsigned long long)cache->key.objectid,
5345                        (unsigned long long)cache->key.offset,
5346                        (unsigned long long)btrfs_block_group_used(&cache->item),
5347                        (unsigned long long)cache->pinned,
5348                        (unsigned long long)cache->reserved);
5349                 btrfs_dump_free_space(cache, bytes);
5350                 spin_unlock(&cache->lock);
5351         }
5352         if (++index < BTRFS_NR_RAID_TYPES)
5353                 goto again;
5354         up_read(&info->groups_sem);
5355 }
5356
5357 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5358                          struct btrfs_root *root,
5359                          u64 num_bytes, u64 min_alloc_size,
5360                          u64 empty_size, u64 hint_byte,
5361                          u64 search_end, struct btrfs_key *ins,
5362                          u64 data)
5363 {
5364         int ret;
5365         u64 search_start = 0;
5366
5367         data = btrfs_get_alloc_profile(root, data);
5368 again:
5369         /*
5370          * the only place that sets empty_size is btrfs_realloc_node, which
5371          * is not called recursively on allocations
5372          */
5373         if (empty_size || root->ref_cows)
5374                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5375                                      num_bytes + 2 * 1024 * 1024, data,
5376                                      CHUNK_ALLOC_NO_FORCE);
5377
5378         WARN_ON(num_bytes < root->sectorsize);
5379         ret = find_free_extent(trans, root, num_bytes, empty_size,
5380                                search_start, search_end, hint_byte,
5381                                ins, data);
5382
5383         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5384                 num_bytes = num_bytes >> 1;
5385                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5386                 num_bytes = max(num_bytes, min_alloc_size);
5387                 do_chunk_alloc(trans, root->fs_info->extent_root,
5388                                num_bytes, data, CHUNK_ALLOC_FORCE);
5389                 goto again;
5390         }
5391         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5392                 struct btrfs_space_info *sinfo;
5393
5394                 sinfo = __find_space_info(root->fs_info, data);
5395                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5396                        "wanted %llu\n", (unsigned long long)data,
5397                        (unsigned long long)num_bytes);
5398                 dump_space_info(sinfo, num_bytes, 1);
5399         }
5400
5401         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5402
5403         return ret;
5404 }
5405
5406 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
5407 {
5408         struct btrfs_block_group_cache *cache;
5409         int ret = 0;
5410
5411         cache = btrfs_lookup_block_group(root->fs_info, start);
5412         if (!cache) {
5413                 printk(KERN_ERR "Unable to find block group for %llu\n",
5414                        (unsigned long long)start);
5415                 return -ENOSPC;
5416         }
5417
5418         if (btrfs_test_opt(root, DISCARD))
5419                 ret = btrfs_discard_extent(root, start, len, NULL);
5420
5421         btrfs_add_free_space(cache, start, len);
5422         btrfs_update_reserved_bytes(cache, len, 0, 1);
5423         btrfs_put_block_group(cache);
5424
5425         trace_btrfs_reserved_extent_free(root, start, len);
5426
5427         return ret;
5428 }
5429
5430 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5431                                       struct btrfs_root *root,
5432                                       u64 parent, u64 root_objectid,
5433                                       u64 flags, u64 owner, u64 offset,
5434                                       struct btrfs_key *ins, int ref_mod)
5435 {
5436         int ret;
5437         struct btrfs_fs_info *fs_info = root->fs_info;
5438         struct btrfs_extent_item *extent_item;
5439         struct btrfs_extent_inline_ref *iref;
5440         struct btrfs_path *path;
5441         struct extent_buffer *leaf;
5442         int type;
5443         u32 size;
5444
5445         if (parent > 0)
5446                 type = BTRFS_SHARED_DATA_REF_KEY;
5447         else
5448                 type = BTRFS_EXTENT_DATA_REF_KEY;
5449
5450         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5451
5452         path = btrfs_alloc_path();
5453         if (!path)
5454                 return -ENOMEM;
5455
5456         path->leave_spinning = 1;
5457         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5458                                       ins, size);
5459         BUG_ON(ret);
5460
5461         leaf = path->nodes[0];
5462         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5463                                      struct btrfs_extent_item);
5464         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5465         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5466         btrfs_set_extent_flags(leaf, extent_item,
5467                                flags | BTRFS_EXTENT_FLAG_DATA);
5468
5469         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5470         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5471         if (parent > 0) {
5472                 struct btrfs_shared_data_ref *ref;
5473                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5474                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5475                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5476         } else {
5477                 struct btrfs_extent_data_ref *ref;
5478                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5479                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5480                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5481                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5482                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5483         }
5484
5485         btrfs_mark_buffer_dirty(path->nodes[0]);
5486         btrfs_free_path(path);
5487
5488         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5489         if (ret) {
5490                 printk(KERN_ERR "btrfs update block group failed for %llu "
5491                        "%llu\n", (unsigned long long)ins->objectid,
5492                        (unsigned long long)ins->offset);
5493                 BUG();
5494         }
5495         return ret;
5496 }
5497
5498 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5499                                      struct btrfs_root *root,
5500                                      u64 parent, u64 root_objectid,
5501                                      u64 flags, struct btrfs_disk_key *key,
5502                                      int level, struct btrfs_key *ins)
5503 {
5504         int ret;
5505         struct btrfs_fs_info *fs_info = root->fs_info;
5506         struct btrfs_extent_item *extent_item;
5507         struct btrfs_tree_block_info *block_info;
5508         struct btrfs_extent_inline_ref *iref;
5509         struct btrfs_path *path;
5510         struct extent_buffer *leaf;
5511         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5512
5513         path = btrfs_alloc_path();
5514         if (!path)
5515                 return -ENOMEM;
5516
5517         path->leave_spinning = 1;
5518         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5519                                       ins, size);
5520         BUG_ON(ret);
5521
5522         leaf = path->nodes[0];
5523         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5524                                      struct btrfs_extent_item);
5525         btrfs_set_extent_refs(leaf, extent_item, 1);
5526         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5527         btrfs_set_extent_flags(leaf, extent_item,
5528                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5529         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5530
5531         btrfs_set_tree_block_key(leaf, block_info, key);
5532         btrfs_set_tree_block_level(leaf, block_info, level);
5533
5534         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5535         if (parent > 0) {
5536                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5537                 btrfs_set_extent_inline_ref_type(leaf, iref,
5538                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5539                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5540         } else {
5541                 btrfs_set_extent_inline_ref_type(leaf, iref,
5542                                                  BTRFS_TREE_BLOCK_REF_KEY);
5543                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5544         }
5545
5546         btrfs_mark_buffer_dirty(leaf);
5547         btrfs_free_path(path);
5548
5549         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5550         if (ret) {
5551                 printk(KERN_ERR "btrfs update block group failed for %llu "
5552                        "%llu\n", (unsigned long long)ins->objectid,
5553                        (unsigned long long)ins->offset);
5554                 BUG();
5555         }
5556         return ret;
5557 }
5558
5559 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5560                                      struct btrfs_root *root,
5561                                      u64 root_objectid, u64 owner,
5562                                      u64 offset, struct btrfs_key *ins)
5563 {
5564         int ret;
5565
5566         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5567
5568         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5569                                          0, root_objectid, owner, offset,
5570                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5571         return ret;
5572 }
5573
5574 /*
5575  * this is used by the tree logging recovery code.  It records that
5576  * an extent has been allocated and makes sure to clear the free
5577  * space cache bits as well
5578  */
5579 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5580                                    struct btrfs_root *root,
5581                                    u64 root_objectid, u64 owner, u64 offset,
5582                                    struct btrfs_key *ins)
5583 {
5584         int ret;
5585         struct btrfs_block_group_cache *block_group;
5586         struct btrfs_caching_control *caching_ctl;
5587         u64 start = ins->objectid;
5588         u64 num_bytes = ins->offset;
5589
5590         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5591         cache_block_group(block_group, trans, NULL, 0);
5592         caching_ctl = get_caching_control(block_group);
5593
5594         if (!caching_ctl) {
5595                 BUG_ON(!block_group_cache_done(block_group));
5596                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5597                 BUG_ON(ret);
5598         } else {
5599                 mutex_lock(&caching_ctl->mutex);
5600
5601                 if (start >= caching_ctl->progress) {
5602                         ret = add_excluded_extent(root, start, num_bytes);
5603                         BUG_ON(ret);
5604                 } else if (start + num_bytes <= caching_ctl->progress) {
5605                         ret = btrfs_remove_free_space(block_group,
5606                                                       start, num_bytes);
5607                         BUG_ON(ret);
5608                 } else {
5609                         num_bytes = caching_ctl->progress - start;
5610                         ret = btrfs_remove_free_space(block_group,
5611                                                       start, num_bytes);
5612                         BUG_ON(ret);
5613
5614                         start = caching_ctl->progress;
5615                         num_bytes = ins->objectid + ins->offset -
5616                                     caching_ctl->progress;
5617                         ret = add_excluded_extent(root, start, num_bytes);
5618                         BUG_ON(ret);
5619                 }
5620
5621                 mutex_unlock(&caching_ctl->mutex);
5622                 put_caching_control(caching_ctl);
5623         }
5624
5625         ret = btrfs_update_reserved_bytes(block_group, ins->offset, 1, 1);
5626         BUG_ON(ret);
5627         btrfs_put_block_group(block_group);
5628         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5629                                          0, owner, offset, ins, 1);
5630         return ret;
5631 }
5632
5633 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5634                                             struct btrfs_root *root,
5635                                             u64 bytenr, u32 blocksize,
5636                                             int level)
5637 {
5638         struct extent_buffer *buf;
5639
5640         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5641         if (!buf)
5642                 return ERR_PTR(-ENOMEM);
5643         btrfs_set_header_generation(buf, trans->transid);
5644         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
5645         btrfs_tree_lock(buf);
5646         clean_tree_block(trans, root, buf);
5647
5648         btrfs_set_lock_blocking(buf);
5649         btrfs_set_buffer_uptodate(buf);
5650
5651         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5652                 /*
5653                  * we allow two log transactions at a time, use different
5654                  * EXENT bit to differentiate dirty pages.
5655                  */
5656                 if (root->log_transid % 2 == 0)
5657                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5658                                         buf->start + buf->len - 1, GFP_NOFS);
5659                 else
5660                         set_extent_new(&root->dirty_log_pages, buf->start,
5661                                         buf->start + buf->len - 1, GFP_NOFS);
5662         } else {
5663                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5664                          buf->start + buf->len - 1, GFP_NOFS);
5665         }
5666         trans->blocks_used++;
5667         /* this returns a buffer locked for blocking */
5668         return buf;
5669 }
5670
5671 static struct btrfs_block_rsv *
5672 use_block_rsv(struct btrfs_trans_handle *trans,
5673               struct btrfs_root *root, u32 blocksize)
5674 {
5675         struct btrfs_block_rsv *block_rsv;
5676         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5677         int ret;
5678
5679         block_rsv = get_block_rsv(trans, root);
5680
5681         if (block_rsv->size == 0) {
5682                 ret = reserve_metadata_bytes(trans, root, block_rsv,
5683                                              blocksize, 0);
5684                 /*
5685                  * If we couldn't reserve metadata bytes try and use some from
5686                  * the global reserve.
5687                  */
5688                 if (ret && block_rsv != global_rsv) {
5689                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5690                         if (!ret)
5691                                 return global_rsv;
5692                         return ERR_PTR(ret);
5693                 } else if (ret) {
5694                         return ERR_PTR(ret);
5695                 }
5696                 return block_rsv;
5697         }
5698
5699         ret = block_rsv_use_bytes(block_rsv, blocksize);
5700         if (!ret)
5701                 return block_rsv;
5702         if (ret) {
5703                 WARN_ON(1);
5704                 ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize,
5705                                              0);
5706                 if (!ret) {
5707                         spin_lock(&block_rsv->lock);
5708                         block_rsv->size += blocksize;
5709                         spin_unlock(&block_rsv->lock);
5710                         return block_rsv;
5711                 } else if (ret && block_rsv != global_rsv) {
5712                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5713                         if (!ret)
5714                                 return global_rsv;
5715                 }
5716         }
5717
5718         return ERR_PTR(-ENOSPC);
5719 }
5720
5721 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
5722 {
5723         block_rsv_add_bytes(block_rsv, blocksize, 0);
5724         block_rsv_release_bytes(block_rsv, NULL, 0);
5725 }
5726
5727 /*
5728  * finds a free extent and does all the dirty work required for allocation
5729  * returns the key for the extent through ins, and a tree buffer for
5730  * the first block of the extent through buf.
5731  *
5732  * returns the tree buffer or NULL.
5733  */
5734 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
5735                                         struct btrfs_root *root, u32 blocksize,
5736                                         u64 parent, u64 root_objectid,
5737                                         struct btrfs_disk_key *key, int level,
5738                                         u64 hint, u64 empty_size)
5739 {
5740         struct btrfs_key ins;
5741         struct btrfs_block_rsv *block_rsv;
5742         struct extent_buffer *buf;
5743         u64 flags = 0;
5744         int ret;
5745
5746
5747         block_rsv = use_block_rsv(trans, root, blocksize);
5748         if (IS_ERR(block_rsv))
5749                 return ERR_CAST(block_rsv);
5750
5751         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
5752                                    empty_size, hint, (u64)-1, &ins, 0);
5753         if (ret) {
5754                 unuse_block_rsv(block_rsv, blocksize);
5755                 return ERR_PTR(ret);
5756         }
5757
5758         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
5759                                     blocksize, level);
5760         BUG_ON(IS_ERR(buf));
5761
5762         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5763                 if (parent == 0)
5764                         parent = ins.objectid;
5765                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5766         } else
5767                 BUG_ON(parent > 0);
5768
5769         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5770                 struct btrfs_delayed_extent_op *extent_op;
5771                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
5772                 BUG_ON(!extent_op);
5773                 if (key)
5774                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
5775                 else
5776                         memset(&extent_op->key, 0, sizeof(extent_op->key));
5777                 extent_op->flags_to_set = flags;
5778                 extent_op->update_key = 1;
5779                 extent_op->update_flags = 1;
5780                 extent_op->is_data = 0;
5781
5782                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
5783                                         ins.offset, parent, root_objectid,
5784                                         level, BTRFS_ADD_DELAYED_EXTENT,
5785                                         extent_op);
5786                 BUG_ON(ret);
5787         }
5788         return buf;
5789 }
5790
5791 struct walk_control {
5792         u64 refs[BTRFS_MAX_LEVEL];
5793         u64 flags[BTRFS_MAX_LEVEL];
5794         struct btrfs_key update_progress;
5795         int stage;
5796         int level;
5797         int shared_level;
5798         int update_ref;
5799         int keep_locks;
5800         int reada_slot;
5801         int reada_count;
5802 };
5803
5804 #define DROP_REFERENCE  1
5805 #define UPDATE_BACKREF  2
5806
5807 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5808                                      struct btrfs_root *root,
5809                                      struct walk_control *wc,
5810                                      struct btrfs_path *path)
5811 {
5812         u64 bytenr;
5813         u64 generation;
5814         u64 refs;
5815         u64 flags;
5816         u32 nritems;
5817         u32 blocksize;
5818         struct btrfs_key key;
5819         struct extent_buffer *eb;
5820         int ret;
5821         int slot;
5822         int nread = 0;
5823
5824         if (path->slots[wc->level] < wc->reada_slot) {
5825                 wc->reada_count = wc->reada_count * 2 / 3;
5826                 wc->reada_count = max(wc->reada_count, 2);
5827         } else {
5828                 wc->reada_count = wc->reada_count * 3 / 2;
5829                 wc->reada_count = min_t(int, wc->reada_count,
5830                                         BTRFS_NODEPTRS_PER_BLOCK(root));
5831         }
5832
5833         eb = path->nodes[wc->level];
5834         nritems = btrfs_header_nritems(eb);
5835         blocksize = btrfs_level_size(root, wc->level - 1);
5836
5837         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5838                 if (nread >= wc->reada_count)
5839                         break;
5840
5841                 cond_resched();
5842                 bytenr = btrfs_node_blockptr(eb, slot);
5843                 generation = btrfs_node_ptr_generation(eb, slot);
5844
5845                 if (slot == path->slots[wc->level])
5846                         goto reada;
5847
5848                 if (wc->stage == UPDATE_BACKREF &&
5849                     generation <= root->root_key.offset)
5850                         continue;
5851
5852                 /* We don't lock the tree block, it's OK to be racy here */
5853                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5854                                                &refs, &flags);
5855                 BUG_ON(ret);
5856                 BUG_ON(refs == 0);
5857
5858                 if (wc->stage == DROP_REFERENCE) {
5859                         if (refs == 1)
5860                                 goto reada;
5861
5862                         if (wc->level == 1 &&
5863                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5864                                 continue;
5865                         if (!wc->update_ref ||
5866                             generation <= root->root_key.offset)
5867                                 continue;
5868                         btrfs_node_key_to_cpu(eb, &key, slot);
5869                         ret = btrfs_comp_cpu_keys(&key,
5870                                                   &wc->update_progress);
5871                         if (ret < 0)
5872                                 continue;
5873                 } else {
5874                         if (wc->level == 1 &&
5875                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5876                                 continue;
5877                 }
5878 reada:
5879                 ret = readahead_tree_block(root, bytenr, blocksize,
5880                                            generation);
5881                 if (ret)
5882                         break;
5883                 nread++;
5884         }
5885         wc->reada_slot = slot;
5886 }
5887
5888 /*
5889  * hepler to process tree block while walking down the tree.
5890  *
5891  * when wc->stage == UPDATE_BACKREF, this function updates
5892  * back refs for pointers in the block.
5893  *
5894  * NOTE: return value 1 means we should stop walking down.
5895  */
5896 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5897                                    struct btrfs_root *root,
5898                                    struct btrfs_path *path,
5899                                    struct walk_control *wc, int lookup_info)
5900 {
5901         int level = wc->level;
5902         struct extent_buffer *eb = path->nodes[level];
5903         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5904         int ret;
5905
5906         if (wc->stage == UPDATE_BACKREF &&
5907             btrfs_header_owner(eb) != root->root_key.objectid)
5908                 return 1;
5909
5910         /*
5911          * when reference count of tree block is 1, it won't increase
5912          * again. once full backref flag is set, we never clear it.
5913          */
5914         if (lookup_info &&
5915             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5916              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5917                 BUG_ON(!path->locks[level]);
5918                 ret = btrfs_lookup_extent_info(trans, root,
5919                                                eb->start, eb->len,
5920                                                &wc->refs[level],
5921                                                &wc->flags[level]);
5922                 BUG_ON(ret);
5923                 BUG_ON(wc->refs[level] == 0);
5924         }
5925
5926         if (wc->stage == DROP_REFERENCE) {
5927                 if (wc->refs[level] > 1)
5928                         return 1;
5929
5930                 if (path->locks[level] && !wc->keep_locks) {
5931                         btrfs_tree_unlock_rw(eb, path->locks[level]);
5932                         path->locks[level] = 0;
5933                 }
5934                 return 0;
5935         }
5936
5937         /* wc->stage == UPDATE_BACKREF */
5938         if (!(wc->flags[level] & flag)) {
5939                 BUG_ON(!path->locks[level]);
5940                 ret = btrfs_inc_ref(trans, root, eb, 1);
5941                 BUG_ON(ret);
5942                 ret = btrfs_dec_ref(trans, root, eb, 0);
5943                 BUG_ON(ret);
5944                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
5945                                                   eb->len, flag, 0);
5946                 BUG_ON(ret);
5947                 wc->flags[level] |= flag;
5948         }
5949
5950         /*
5951          * the block is shared by multiple trees, so it's not good to
5952          * keep the tree lock
5953          */
5954         if (path->locks[level] && level > 0) {
5955                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5956                 path->locks[level] = 0;
5957         }
5958         return 0;
5959 }
5960
5961 /*
5962  * hepler to process tree block pointer.
5963  *
5964  * when wc->stage == DROP_REFERENCE, this function checks
5965  * reference count of the block pointed to. if the block
5966  * is shared and we need update back refs for the subtree
5967  * rooted at the block, this function changes wc->stage to
5968  * UPDATE_BACKREF. if the block is shared and there is no
5969  * need to update back, this function drops the reference
5970  * to the block.
5971  *
5972  * NOTE: return value 1 means we should stop walking down.
5973  */
5974 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5975                                  struct btrfs_root *root,
5976                                  struct btrfs_path *path,
5977                                  struct walk_control *wc, int *lookup_info)
5978 {
5979         u64 bytenr;
5980         u64 generation;
5981         u64 parent;
5982         u32 blocksize;
5983         struct btrfs_key key;
5984         struct extent_buffer *next;
5985         int level = wc->level;
5986         int reada = 0;
5987         int ret = 0;
5988
5989         generation = btrfs_node_ptr_generation(path->nodes[level],
5990                                                path->slots[level]);
5991         /*
5992          * if the lower level block was created before the snapshot
5993          * was created, we know there is no need to update back refs
5994          * for the subtree
5995          */
5996         if (wc->stage == UPDATE_BACKREF &&
5997             generation <= root->root_key.offset) {
5998                 *lookup_info = 1;
5999                 return 1;
6000         }
6001
6002         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6003         blocksize = btrfs_level_size(root, level - 1);
6004
6005         next = btrfs_find_tree_block(root, bytenr, blocksize);
6006         if (!next) {
6007                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6008                 if (!next)
6009                         return -ENOMEM;
6010                 reada = 1;
6011         }
6012         btrfs_tree_lock(next);
6013         btrfs_set_lock_blocking(next);
6014
6015         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6016                                        &wc->refs[level - 1],
6017                                        &wc->flags[level - 1]);
6018         BUG_ON(ret);
6019         BUG_ON(wc->refs[level - 1] == 0);
6020         *lookup_info = 0;
6021
6022         if (wc->stage == DROP_REFERENCE) {
6023                 if (wc->refs[level - 1] > 1) {
6024                         if (level == 1 &&
6025                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6026                                 goto skip;
6027
6028                         if (!wc->update_ref ||
6029                             generation <= root->root_key.offset)
6030                                 goto skip;
6031
6032                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6033                                               path->slots[level]);
6034                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6035                         if (ret < 0)
6036                                 goto skip;
6037
6038                         wc->stage = UPDATE_BACKREF;
6039                         wc->shared_level = level - 1;
6040                 }
6041         } else {
6042                 if (level == 1 &&
6043                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6044                         goto skip;
6045         }
6046
6047         if (!btrfs_buffer_uptodate(next, generation)) {
6048                 btrfs_tree_unlock(next);
6049                 free_extent_buffer(next);
6050                 next = NULL;
6051                 *lookup_info = 1;
6052         }
6053
6054         if (!next) {
6055                 if (reada && level == 1)
6056                         reada_walk_down(trans, root, wc, path);
6057                 next = read_tree_block(root, bytenr, blocksize, generation);
6058                 if (!next)
6059                         return -EIO;
6060                 btrfs_tree_lock(next);
6061                 btrfs_set_lock_blocking(next);
6062         }
6063
6064         level--;
6065         BUG_ON(level != btrfs_header_level(next));
6066         path->nodes[level] = next;
6067         path->slots[level] = 0;
6068         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6069         wc->level = level;
6070         if (wc->level == 1)
6071                 wc->reada_slot = 0;
6072         return 0;
6073 skip:
6074         wc->refs[level - 1] = 0;
6075         wc->flags[level - 1] = 0;
6076         if (wc->stage == DROP_REFERENCE) {
6077                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6078                         parent = path->nodes[level]->start;
6079                 } else {
6080                         BUG_ON(root->root_key.objectid !=
6081                                btrfs_header_owner(path->nodes[level]));
6082                         parent = 0;
6083                 }
6084
6085                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6086                                         root->root_key.objectid, level - 1, 0);
6087                 BUG_ON(ret);
6088         }
6089         btrfs_tree_unlock(next);
6090         free_extent_buffer(next);
6091         *lookup_info = 1;
6092         return 1;
6093 }
6094
6095 /*
6096  * hepler to process tree block while walking up the tree.
6097  *
6098  * when wc->stage == DROP_REFERENCE, this function drops
6099  * reference count on the block.
6100  *
6101  * when wc->stage == UPDATE_BACKREF, this function changes
6102  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6103  * to UPDATE_BACKREF previously while processing the block.
6104  *
6105  * NOTE: return value 1 means we should stop walking up.
6106  */
6107 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6108                                  struct btrfs_root *root,
6109                                  struct btrfs_path *path,
6110                                  struct walk_control *wc)
6111 {
6112         int ret;
6113         int level = wc->level;
6114         struct extent_buffer *eb = path->nodes[level];
6115         u64 parent = 0;
6116
6117         if (wc->stage == UPDATE_BACKREF) {
6118                 BUG_ON(wc->shared_level < level);
6119                 if (level < wc->shared_level)
6120                         goto out;
6121
6122                 ret = find_next_key(path, level + 1, &wc->update_progress);
6123                 if (ret > 0)
6124                         wc->update_ref = 0;
6125
6126                 wc->stage = DROP_REFERENCE;
6127                 wc->shared_level = -1;
6128                 path->slots[level] = 0;
6129
6130                 /*
6131                  * check reference count again if the block isn't locked.
6132                  * we should start walking down the tree again if reference
6133                  * count is one.
6134                  */
6135                 if (!path->locks[level]) {
6136                         BUG_ON(level == 0);
6137                         btrfs_tree_lock(eb);
6138                         btrfs_set_lock_blocking(eb);
6139                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6140
6141                         ret = btrfs_lookup_extent_info(trans, root,
6142                                                        eb->start, eb->len,
6143                                                        &wc->refs[level],
6144                                                        &wc->flags[level]);
6145                         BUG_ON(ret);
6146                         BUG_ON(wc->refs[level] == 0);
6147                         if (wc->refs[level] == 1) {
6148                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6149                                 return 1;
6150                         }
6151                 }
6152         }
6153
6154         /* wc->stage == DROP_REFERENCE */
6155         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6156
6157         if (wc->refs[level] == 1) {
6158                 if (level == 0) {
6159                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6160                                 ret = btrfs_dec_ref(trans, root, eb, 1);
6161                         else
6162                                 ret = btrfs_dec_ref(trans, root, eb, 0);
6163                         BUG_ON(ret);
6164                 }
6165                 /* make block locked assertion in clean_tree_block happy */
6166                 if (!path->locks[level] &&
6167                     btrfs_header_generation(eb) == trans->transid) {
6168                         btrfs_tree_lock(eb);
6169                         btrfs_set_lock_blocking(eb);
6170                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6171                 }
6172                 clean_tree_block(trans, root, eb);
6173         }
6174
6175         if (eb == root->node) {
6176                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6177                         parent = eb->start;
6178                 else
6179                         BUG_ON(root->root_key.objectid !=
6180                                btrfs_header_owner(eb));
6181         } else {
6182                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6183                         parent = path->nodes[level + 1]->start;
6184                 else
6185                         BUG_ON(root->root_key.objectid !=
6186                                btrfs_header_owner(path->nodes[level + 1]));
6187         }
6188
6189         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6190 out:
6191         wc->refs[level] = 0;
6192         wc->flags[level] = 0;
6193         return 0;
6194 }
6195
6196 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6197                                    struct btrfs_root *root,
6198                                    struct btrfs_path *path,
6199                                    struct walk_control *wc)
6200 {
6201         int level = wc->level;
6202         int lookup_info = 1;
6203         int ret;
6204
6205         while (level >= 0) {
6206                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6207                 if (ret > 0)
6208                         break;
6209
6210                 if (level == 0)
6211                         break;
6212
6213                 if (path->slots[level] >=
6214                     btrfs_header_nritems(path->nodes[level]))
6215                         break;
6216
6217                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6218                 if (ret > 0) {
6219                         path->slots[level]++;
6220                         continue;
6221                 } else if (ret < 0)
6222                         return ret;
6223                 level = wc->level;
6224         }
6225         return 0;
6226 }
6227
6228 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6229                                  struct btrfs_root *root,
6230                                  struct btrfs_path *path,
6231                                  struct walk_control *wc, int max_level)
6232 {
6233         int level = wc->level;
6234         int ret;
6235
6236         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6237         while (level < max_level && path->nodes[level]) {
6238                 wc->level = level;
6239                 if (path->slots[level] + 1 <
6240                     btrfs_header_nritems(path->nodes[level])) {
6241                         path->slots[level]++;
6242                         return 0;
6243                 } else {
6244                         ret = walk_up_proc(trans, root, path, wc);
6245                         if (ret > 0)
6246                                 return 0;
6247
6248                         if (path->locks[level]) {
6249                                 btrfs_tree_unlock_rw(path->nodes[level],
6250                                                      path->locks[level]);
6251                                 path->locks[level] = 0;
6252                         }
6253                         free_extent_buffer(path->nodes[level]);
6254                         path->nodes[level] = NULL;
6255                         level++;
6256                 }
6257         }
6258         return 1;
6259 }
6260
6261 /*
6262  * drop a subvolume tree.
6263  *
6264  * this function traverses the tree freeing any blocks that only
6265  * referenced by the tree.
6266  *
6267  * when a shared tree block is found. this function decreases its
6268  * reference count by one. if update_ref is true, this function
6269  * also make sure backrefs for the shared block and all lower level
6270  * blocks are properly updated.
6271  */
6272 int btrfs_drop_snapshot(struct btrfs_root *root,
6273                         struct btrfs_block_rsv *block_rsv, int update_ref)
6274 {
6275         struct btrfs_path *path;
6276         struct btrfs_trans_handle *trans;
6277         struct btrfs_root *tree_root = root->fs_info->tree_root;
6278         struct btrfs_root_item *root_item = &root->root_item;
6279         struct walk_control *wc;
6280         struct btrfs_key key;
6281         int err = 0;
6282         int ret;
6283         int level;
6284
6285         path = btrfs_alloc_path();
6286         if (!path)
6287                 return -ENOMEM;
6288
6289         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6290         if (!wc) {
6291                 btrfs_free_path(path);
6292                 return -ENOMEM;
6293         }
6294
6295         trans = btrfs_start_transaction(tree_root, 0);
6296         BUG_ON(IS_ERR(trans));
6297
6298         if (block_rsv)
6299                 trans->block_rsv = block_rsv;
6300
6301         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6302                 level = btrfs_header_level(root->node);
6303                 path->nodes[level] = btrfs_lock_root_node(root);
6304                 btrfs_set_lock_blocking(path->nodes[level]);
6305                 path->slots[level] = 0;
6306                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6307                 memset(&wc->update_progress, 0,
6308                        sizeof(wc->update_progress));
6309         } else {
6310                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6311                 memcpy(&wc->update_progress, &key,
6312                        sizeof(wc->update_progress));
6313
6314                 level = root_item->drop_level;
6315                 BUG_ON(level == 0);
6316                 path->lowest_level = level;
6317                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6318                 path->lowest_level = 0;
6319                 if (ret < 0) {
6320                         err = ret;
6321                         goto out;
6322                 }
6323                 WARN_ON(ret > 0);
6324
6325                 /*
6326                  * unlock our path, this is safe because only this
6327                  * function is allowed to delete this snapshot
6328                  */
6329                 btrfs_unlock_up_safe(path, 0);
6330
6331                 level = btrfs_header_level(root->node);
6332                 while (1) {
6333                         btrfs_tree_lock(path->nodes[level]);
6334                         btrfs_set_lock_blocking(path->nodes[level]);
6335
6336                         ret = btrfs_lookup_extent_info(trans, root,
6337                                                 path->nodes[level]->start,
6338                                                 path->nodes[level]->len,
6339                                                 &wc->refs[level],
6340                                                 &wc->flags[level]);
6341                         BUG_ON(ret);
6342                         BUG_ON(wc->refs[level] == 0);
6343
6344                         if (level == root_item->drop_level)
6345                                 break;
6346
6347                         btrfs_tree_unlock(path->nodes[level]);
6348                         WARN_ON(wc->refs[level] != 1);
6349                         level--;
6350                 }
6351         }
6352
6353         wc->level = level;
6354         wc->shared_level = -1;
6355         wc->stage = DROP_REFERENCE;
6356         wc->update_ref = update_ref;
6357         wc->keep_locks = 0;
6358         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6359
6360         while (1) {
6361                 ret = walk_down_tree(trans, root, path, wc);
6362                 if (ret < 0) {
6363                         err = ret;
6364                         break;
6365                 }
6366
6367                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6368                 if (ret < 0) {
6369                         err = ret;
6370                         break;
6371                 }
6372
6373                 if (ret > 0) {
6374                         BUG_ON(wc->stage != DROP_REFERENCE);
6375                         break;
6376                 }
6377
6378                 if (wc->stage == DROP_REFERENCE) {
6379                         level = wc->level;
6380                         btrfs_node_key(path->nodes[level],
6381                                        &root_item->drop_progress,
6382                                        path->slots[level]);
6383                         root_item->drop_level = level;
6384                 }
6385
6386                 BUG_ON(wc->level == 0);
6387                 if (btrfs_should_end_transaction(trans, tree_root)) {
6388                         ret = btrfs_update_root(trans, tree_root,
6389                                                 &root->root_key,
6390                                                 root_item);
6391                         BUG_ON(ret);
6392
6393                         btrfs_end_transaction_throttle(trans, tree_root);
6394                         trans = btrfs_start_transaction(tree_root, 0);
6395                         BUG_ON(IS_ERR(trans));
6396                         if (block_rsv)
6397                                 trans->block_rsv = block_rsv;
6398                 }
6399         }
6400         btrfs_release_path(path);
6401         BUG_ON(err);
6402
6403         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6404         BUG_ON(ret);
6405
6406         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6407                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6408                                            NULL, NULL);
6409                 BUG_ON(ret < 0);
6410                 if (ret > 0) {
6411                         /* if we fail to delete the orphan item this time
6412                          * around, it'll get picked up the next time.
6413                          *
6414                          * The most common failure here is just -ENOENT.
6415                          */
6416                         btrfs_del_orphan_item(trans, tree_root,
6417                                               root->root_key.objectid);
6418                 }
6419         }
6420
6421         if (root->in_radix) {
6422                 btrfs_free_fs_root(tree_root->fs_info, root);
6423         } else {
6424                 free_extent_buffer(root->node);
6425                 free_extent_buffer(root->commit_root);
6426                 kfree(root);
6427         }
6428 out:
6429         btrfs_end_transaction_throttle(trans, tree_root);
6430         kfree(wc);
6431         btrfs_free_path(path);
6432         return err;
6433 }
6434
6435 /*
6436  * drop subtree rooted at tree block 'node'.
6437  *
6438  * NOTE: this function will unlock and release tree block 'node'
6439  */
6440 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6441                         struct btrfs_root *root,
6442                         struct extent_buffer *node,
6443                         struct extent_buffer *parent)
6444 {
6445         struct btrfs_path *path;
6446         struct walk_control *wc;
6447         int level;
6448         int parent_level;
6449         int ret = 0;
6450         int wret;
6451
6452         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6453
6454         path = btrfs_alloc_path();
6455         if (!path)
6456                 return -ENOMEM;
6457
6458         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6459         if (!wc) {
6460                 btrfs_free_path(path);
6461                 return -ENOMEM;
6462         }
6463
6464         btrfs_assert_tree_locked(parent);
6465         parent_level = btrfs_header_level(parent);
6466         extent_buffer_get(parent);
6467         path->nodes[parent_level] = parent;
6468         path->slots[parent_level] = btrfs_header_nritems(parent);
6469
6470         btrfs_assert_tree_locked(node);
6471         level = btrfs_header_level(node);
6472         path->nodes[level] = node;
6473         path->slots[level] = 0;
6474         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6475
6476         wc->refs[parent_level] = 1;
6477         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6478         wc->level = level;
6479         wc->shared_level = -1;
6480         wc->stage = DROP_REFERENCE;
6481         wc->update_ref = 0;
6482         wc->keep_locks = 1;
6483         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6484
6485         while (1) {
6486                 wret = walk_down_tree(trans, root, path, wc);
6487                 if (wret < 0) {
6488                         ret = wret;
6489                         break;
6490                 }
6491
6492                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6493                 if (wret < 0)
6494                         ret = wret;
6495                 if (wret != 0)
6496                         break;
6497         }
6498
6499         kfree(wc);
6500         btrfs_free_path(path);
6501         return ret;
6502 }
6503
6504 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6505 {
6506         u64 num_devices;
6507         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6508                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6509
6510         /*
6511          * we add in the count of missing devices because we want
6512          * to make sure that any RAID levels on a degraded FS
6513          * continue to be honored.
6514          */
6515         num_devices = root->fs_info->fs_devices->rw_devices +
6516                 root->fs_info->fs_devices->missing_devices;
6517
6518         if (num_devices == 1) {
6519                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6520                 stripped = flags & ~stripped;
6521
6522                 /* turn raid0 into single device chunks */
6523                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6524                         return stripped;
6525
6526                 /* turn mirroring into duplication */
6527                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6528                              BTRFS_BLOCK_GROUP_RAID10))
6529                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6530                 return flags;
6531         } else {
6532                 /* they already had raid on here, just return */
6533                 if (flags & stripped)
6534                         return flags;
6535
6536                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6537                 stripped = flags & ~stripped;
6538
6539                 /* switch duplicated blocks with raid1 */
6540                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6541                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6542
6543                 /* turn single device chunks into raid0 */
6544                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6545         }
6546         return flags;
6547 }
6548
6549 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
6550 {
6551         struct btrfs_space_info *sinfo = cache->space_info;
6552         u64 num_bytes;
6553         u64 min_allocable_bytes;
6554         int ret = -ENOSPC;
6555
6556
6557         /*
6558          * We need some metadata space and system metadata space for
6559          * allocating chunks in some corner cases until we force to set
6560          * it to be readonly.
6561          */
6562         if ((sinfo->flags &
6563              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
6564             !force)
6565                 min_allocable_bytes = 1 * 1024 * 1024;
6566         else
6567                 min_allocable_bytes = 0;
6568
6569         spin_lock(&sinfo->lock);
6570         spin_lock(&cache->lock);
6571
6572         if (cache->ro) {
6573                 ret = 0;
6574                 goto out;
6575         }
6576
6577         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6578                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6579
6580         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
6581             sinfo->bytes_may_use + sinfo->bytes_readonly +
6582             cache->reserved_pinned + num_bytes + min_allocable_bytes <=
6583             sinfo->total_bytes) {
6584                 sinfo->bytes_readonly += num_bytes;
6585                 sinfo->bytes_reserved += cache->reserved_pinned;
6586                 cache->reserved_pinned = 0;
6587                 cache->ro = 1;
6588                 ret = 0;
6589         }
6590 out:
6591         spin_unlock(&cache->lock);
6592         spin_unlock(&sinfo->lock);
6593         return ret;
6594 }
6595
6596 int btrfs_set_block_group_ro(struct btrfs_root *root,
6597                              struct btrfs_block_group_cache *cache)
6598
6599 {
6600         struct btrfs_trans_handle *trans;
6601         u64 alloc_flags;
6602         int ret;
6603
6604         BUG_ON(cache->ro);
6605
6606         trans = btrfs_join_transaction(root);
6607         BUG_ON(IS_ERR(trans));
6608
6609         alloc_flags = update_block_group_flags(root, cache->flags);
6610         if (alloc_flags != cache->flags)
6611                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6612                                CHUNK_ALLOC_FORCE);
6613
6614         ret = set_block_group_ro(cache, 0);
6615         if (!ret)
6616                 goto out;
6617         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
6618         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6619                              CHUNK_ALLOC_FORCE);
6620         if (ret < 0)
6621                 goto out;
6622         ret = set_block_group_ro(cache, 0);
6623 out:
6624         btrfs_end_transaction(trans, root);
6625         return ret;
6626 }
6627
6628 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
6629                             struct btrfs_root *root, u64 type)
6630 {
6631         u64 alloc_flags = get_alloc_profile(root, type);
6632         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6633                               CHUNK_ALLOC_FORCE);
6634 }
6635
6636 /*
6637  * helper to account the unused space of all the readonly block group in the
6638  * list. takes mirrors into account.
6639  */
6640 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
6641 {
6642         struct btrfs_block_group_cache *block_group;
6643         u64 free_bytes = 0;
6644         int factor;
6645
6646         list_for_each_entry(block_group, groups_list, list) {
6647                 spin_lock(&block_group->lock);
6648
6649                 if (!block_group->ro) {
6650                         spin_unlock(&block_group->lock);
6651                         continue;
6652                 }
6653
6654                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
6655                                           BTRFS_BLOCK_GROUP_RAID10 |
6656                                           BTRFS_BLOCK_GROUP_DUP))
6657                         factor = 2;
6658                 else
6659                         factor = 1;
6660
6661                 free_bytes += (block_group->key.offset -
6662                                btrfs_block_group_used(&block_group->item)) *
6663                                factor;
6664
6665                 spin_unlock(&block_group->lock);
6666         }
6667
6668         return free_bytes;
6669 }
6670
6671 /*
6672  * helper to account the unused space of all the readonly block group in the
6673  * space_info. takes mirrors into account.
6674  */
6675 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
6676 {
6677         int i;
6678         u64 free_bytes = 0;
6679
6680         spin_lock(&sinfo->lock);
6681
6682         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
6683                 if (!list_empty(&sinfo->block_groups[i]))
6684                         free_bytes += __btrfs_get_ro_block_group_free_space(
6685                                                 &sinfo->block_groups[i]);
6686
6687         spin_unlock(&sinfo->lock);
6688
6689         return free_bytes;
6690 }
6691
6692 int btrfs_set_block_group_rw(struct btrfs_root *root,
6693                               struct btrfs_block_group_cache *cache)
6694 {
6695         struct btrfs_space_info *sinfo = cache->space_info;
6696         u64 num_bytes;
6697
6698         BUG_ON(!cache->ro);
6699
6700         spin_lock(&sinfo->lock);
6701         spin_lock(&cache->lock);
6702         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6703                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6704         sinfo->bytes_readonly -= num_bytes;
6705         cache->ro = 0;
6706         spin_unlock(&cache->lock);
6707         spin_unlock(&sinfo->lock);
6708         return 0;
6709 }
6710
6711 /*
6712  * checks to see if its even possible to relocate this block group.
6713  *
6714  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
6715  * ok to go ahead and try.
6716  */
6717 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
6718 {
6719         struct btrfs_block_group_cache *block_group;
6720         struct btrfs_space_info *space_info;
6721         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6722         struct btrfs_device *device;
6723         int full = 0;
6724         int ret = 0;
6725
6726         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
6727
6728         /* odd, couldn't find the block group, leave it alone */
6729         if (!block_group)
6730                 return -1;
6731
6732         /* no bytes used, we're good */
6733         if (!btrfs_block_group_used(&block_group->item))
6734                 goto out;
6735
6736         space_info = block_group->space_info;
6737         spin_lock(&space_info->lock);
6738
6739         full = space_info->full;
6740
6741         /*
6742          * if this is the last block group we have in this space, we can't
6743          * relocate it unless we're able to allocate a new chunk below.
6744          *
6745          * Otherwise, we need to make sure we have room in the space to handle
6746          * all of the extents from this block group.  If we can, we're good
6747          */
6748         if ((space_info->total_bytes != block_group->key.offset) &&
6749            (space_info->bytes_used + space_info->bytes_reserved +
6750             space_info->bytes_pinned + space_info->bytes_readonly +
6751             btrfs_block_group_used(&block_group->item) <
6752             space_info->total_bytes)) {
6753                 spin_unlock(&space_info->lock);
6754                 goto out;
6755         }
6756         spin_unlock(&space_info->lock);
6757
6758         /*
6759          * ok we don't have enough space, but maybe we have free space on our
6760          * devices to allocate new chunks for relocation, so loop through our
6761          * alloc devices and guess if we have enough space.  However, if we
6762          * were marked as full, then we know there aren't enough chunks, and we
6763          * can just return.
6764          */
6765         ret = -1;
6766         if (full)
6767                 goto out;
6768
6769         mutex_lock(&root->fs_info->chunk_mutex);
6770         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
6771                 u64 min_free = btrfs_block_group_used(&block_group->item);
6772                 u64 dev_offset;
6773
6774                 /*
6775                  * check to make sure we can actually find a chunk with enough
6776                  * space to fit our block group in.
6777                  */
6778                 if (device->total_bytes > device->bytes_used + min_free) {
6779                         ret = find_free_dev_extent(NULL, device, min_free,
6780                                                    &dev_offset, NULL);
6781                         if (!ret)
6782                                 break;
6783                         ret = -1;
6784                 }
6785         }
6786         mutex_unlock(&root->fs_info->chunk_mutex);
6787 out:
6788         btrfs_put_block_group(block_group);
6789         return ret;
6790 }
6791
6792 static int find_first_block_group(struct btrfs_root *root,
6793                 struct btrfs_path *path, struct btrfs_key *key)
6794 {
6795         int ret = 0;
6796         struct btrfs_key found_key;
6797         struct extent_buffer *leaf;
6798         int slot;
6799
6800         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
6801         if (ret < 0)
6802                 goto out;
6803
6804         while (1) {
6805                 slot = path->slots[0];
6806                 leaf = path->nodes[0];
6807                 if (slot >= btrfs_header_nritems(leaf)) {
6808                         ret = btrfs_next_leaf(root, path);
6809                         if (ret == 0)
6810                                 continue;
6811                         if (ret < 0)
6812                                 goto out;
6813                         break;
6814                 }
6815                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6816
6817                 if (found_key.objectid >= key->objectid &&
6818                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
6819                         ret = 0;
6820                         goto out;
6821                 }
6822                 path->slots[0]++;
6823         }
6824 out:
6825         return ret;
6826 }
6827
6828 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
6829 {
6830         struct btrfs_block_group_cache *block_group;
6831         u64 last = 0;
6832
6833         while (1) {
6834                 struct inode *inode;
6835
6836                 block_group = btrfs_lookup_first_block_group(info, last);
6837                 while (block_group) {
6838                         spin_lock(&block_group->lock);
6839                         if (block_group->iref)
6840                                 break;
6841                         spin_unlock(&block_group->lock);
6842                         block_group = next_block_group(info->tree_root,
6843                                                        block_group);
6844                 }
6845                 if (!block_group) {
6846                         if (last == 0)
6847                                 break;
6848                         last = 0;
6849                         continue;
6850                 }
6851
6852                 inode = block_group->inode;
6853                 block_group->iref = 0;
6854                 block_group->inode = NULL;
6855                 spin_unlock(&block_group->lock);
6856                 iput(inode);
6857                 last = block_group->key.objectid + block_group->key.offset;
6858                 btrfs_put_block_group(block_group);
6859         }
6860 }
6861
6862 int btrfs_free_block_groups(struct btrfs_fs_info *info)
6863 {
6864         struct btrfs_block_group_cache *block_group;
6865         struct btrfs_space_info *space_info;
6866         struct btrfs_caching_control *caching_ctl;
6867         struct rb_node *n;
6868
6869         down_write(&info->extent_commit_sem);
6870         while (!list_empty(&info->caching_block_groups)) {
6871                 caching_ctl = list_entry(info->caching_block_groups.next,
6872                                          struct btrfs_caching_control, list);
6873                 list_del(&caching_ctl->list);
6874                 put_caching_control(caching_ctl);
6875         }
6876         up_write(&info->extent_commit_sem);
6877
6878         spin_lock(&info->block_group_cache_lock);
6879         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
6880                 block_group = rb_entry(n, struct btrfs_block_group_cache,
6881                                        cache_node);
6882                 rb_erase(&block_group->cache_node,
6883                          &info->block_group_cache_tree);
6884                 spin_unlock(&info->block_group_cache_lock);
6885
6886                 down_write(&block_group->space_info->groups_sem);
6887                 list_del(&block_group->list);
6888                 up_write(&block_group->space_info->groups_sem);
6889
6890                 if (block_group->cached == BTRFS_CACHE_STARTED)
6891                         wait_block_group_cache_done(block_group);
6892
6893                 /*
6894                  * We haven't cached this block group, which means we could
6895                  * possibly have excluded extents on this block group.
6896                  */
6897                 if (block_group->cached == BTRFS_CACHE_NO)
6898                         free_excluded_extents(info->extent_root, block_group);
6899
6900                 btrfs_remove_free_space_cache(block_group);
6901                 btrfs_put_block_group(block_group);
6902
6903                 spin_lock(&info->block_group_cache_lock);
6904         }
6905         spin_unlock(&info->block_group_cache_lock);
6906
6907         /* now that all the block groups are freed, go through and
6908          * free all the space_info structs.  This is only called during
6909          * the final stages of unmount, and so we know nobody is
6910          * using them.  We call synchronize_rcu() once before we start,
6911          * just to be on the safe side.
6912          */
6913         synchronize_rcu();
6914
6915         release_global_block_rsv(info);
6916
6917         while(!list_empty(&info->space_info)) {
6918                 space_info = list_entry(info->space_info.next,
6919                                         struct btrfs_space_info,
6920                                         list);
6921                 if (space_info->bytes_pinned > 0 ||
6922                     space_info->bytes_reserved > 0) {
6923                         WARN_ON(1);
6924                         dump_space_info(space_info, 0, 0);
6925                 }
6926                 list_del(&space_info->list);
6927                 kfree(space_info);
6928         }
6929         return 0;
6930 }
6931
6932 static void __link_block_group(struct btrfs_space_info *space_info,
6933                                struct btrfs_block_group_cache *cache)
6934 {
6935         int index = get_block_group_index(cache);
6936
6937         down_write(&space_info->groups_sem);
6938         list_add_tail(&cache->list, &space_info->block_groups[index]);
6939         up_write(&space_info->groups_sem);
6940 }
6941
6942 int btrfs_read_block_groups(struct btrfs_root *root)
6943 {
6944         struct btrfs_path *path;
6945         int ret;
6946         struct btrfs_block_group_cache *cache;
6947         struct btrfs_fs_info *info = root->fs_info;
6948         struct btrfs_space_info *space_info;
6949         struct btrfs_key key;
6950         struct btrfs_key found_key;
6951         struct extent_buffer *leaf;
6952         int need_clear = 0;
6953         u64 cache_gen;
6954
6955         root = info->extent_root;
6956         key.objectid = 0;
6957         key.offset = 0;
6958         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
6959         path = btrfs_alloc_path();
6960         if (!path)
6961                 return -ENOMEM;
6962         path->reada = 1;
6963
6964         cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
6965         if (cache_gen != 0 &&
6966             btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
6967                 need_clear = 1;
6968         if (btrfs_test_opt(root, CLEAR_CACHE))
6969                 need_clear = 1;
6970         if (!btrfs_test_opt(root, SPACE_CACHE) && cache_gen)
6971                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
6972
6973         while (1) {
6974                 ret = find_first_block_group(root, path, &key);
6975                 if (ret > 0)
6976                         break;
6977                 if (ret != 0)
6978                         goto error;
6979                 leaf = path->nodes[0];
6980                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6981                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
6982                 if (!cache) {
6983                         ret = -ENOMEM;
6984                         goto error;
6985                 }
6986                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
6987                                                 GFP_NOFS);
6988                 if (!cache->free_space_ctl) {
6989                         kfree(cache);
6990                         ret = -ENOMEM;
6991                         goto error;
6992                 }
6993
6994                 atomic_set(&cache->count, 1);
6995                 spin_lock_init(&cache->lock);
6996                 cache->fs_info = info;
6997                 INIT_LIST_HEAD(&cache->list);
6998                 INIT_LIST_HEAD(&cache->cluster_list);
6999
7000                 if (need_clear)
7001                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7002
7003                 read_extent_buffer(leaf, &cache->item,
7004                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7005                                    sizeof(cache->item));
7006                 memcpy(&cache->key, &found_key, sizeof(found_key));
7007
7008                 key.objectid = found_key.objectid + found_key.offset;
7009                 btrfs_release_path(path);
7010                 cache->flags = btrfs_block_group_flags(&cache->item);
7011                 cache->sectorsize = root->sectorsize;
7012
7013                 btrfs_init_free_space_ctl(cache);
7014
7015                 /*
7016                  * We need to exclude the super stripes now so that the space
7017                  * info has super bytes accounted for, otherwise we'll think
7018                  * we have more space than we actually do.
7019                  */
7020                 exclude_super_stripes(root, cache);
7021
7022                 /*
7023                  * check for two cases, either we are full, and therefore
7024                  * don't need to bother with the caching work since we won't
7025                  * find any space, or we are empty, and we can just add all
7026                  * the space in and be done with it.  This saves us _alot_ of
7027                  * time, particularly in the full case.
7028                  */
7029                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7030                         cache->last_byte_to_unpin = (u64)-1;
7031                         cache->cached = BTRFS_CACHE_FINISHED;
7032                         free_excluded_extents(root, cache);
7033                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7034                         cache->last_byte_to_unpin = (u64)-1;
7035                         cache->cached = BTRFS_CACHE_FINISHED;
7036                         add_new_free_space(cache, root->fs_info,
7037                                            found_key.objectid,
7038                                            found_key.objectid +
7039                                            found_key.offset);
7040                         free_excluded_extents(root, cache);
7041                 }
7042
7043                 ret = update_space_info(info, cache->flags, found_key.offset,
7044                                         btrfs_block_group_used(&cache->item),
7045                                         &space_info);
7046                 BUG_ON(ret);
7047                 cache->space_info = space_info;
7048                 spin_lock(&cache->space_info->lock);
7049                 cache->space_info->bytes_readonly += cache->bytes_super;
7050                 spin_unlock(&cache->space_info->lock);
7051
7052                 __link_block_group(space_info, cache);
7053
7054                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7055                 BUG_ON(ret);
7056
7057                 set_avail_alloc_bits(root->fs_info, cache->flags);
7058                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7059                         set_block_group_ro(cache, 1);
7060         }
7061
7062         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7063                 if (!(get_alloc_profile(root, space_info->flags) &
7064                       (BTRFS_BLOCK_GROUP_RAID10 |
7065                        BTRFS_BLOCK_GROUP_RAID1 |
7066                        BTRFS_BLOCK_GROUP_DUP)))
7067                         continue;
7068                 /*
7069                  * avoid allocating from un-mirrored block group if there are
7070                  * mirrored block groups.
7071                  */
7072                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7073                         set_block_group_ro(cache, 1);
7074                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7075                         set_block_group_ro(cache, 1);
7076         }
7077
7078         init_global_block_rsv(info);
7079         ret = 0;
7080 error:
7081         btrfs_free_path(path);
7082         return ret;
7083 }
7084
7085 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7086                            struct btrfs_root *root, u64 bytes_used,
7087                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7088                            u64 size)
7089 {
7090         int ret;
7091         struct btrfs_root *extent_root;
7092         struct btrfs_block_group_cache *cache;
7093
7094         extent_root = root->fs_info->extent_root;
7095
7096         root->fs_info->last_trans_log_full_commit = trans->transid;
7097
7098         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7099         if (!cache)
7100                 return -ENOMEM;
7101         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7102                                         GFP_NOFS);
7103         if (!cache->free_space_ctl) {
7104                 kfree(cache);
7105                 return -ENOMEM;
7106         }
7107
7108         cache->key.objectid = chunk_offset;
7109         cache->key.offset = size;
7110         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7111         cache->sectorsize = root->sectorsize;
7112         cache->fs_info = root->fs_info;
7113
7114         atomic_set(&cache->count, 1);
7115         spin_lock_init(&cache->lock);
7116         INIT_LIST_HEAD(&cache->list);
7117         INIT_LIST_HEAD(&cache->cluster_list);
7118
7119         btrfs_init_free_space_ctl(cache);
7120
7121         btrfs_set_block_group_used(&cache->item, bytes_used);
7122         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7123         cache->flags = type;
7124         btrfs_set_block_group_flags(&cache->item, type);
7125
7126         cache->last_byte_to_unpin = (u64)-1;
7127         cache->cached = BTRFS_CACHE_FINISHED;
7128         exclude_super_stripes(root, cache);
7129
7130         add_new_free_space(cache, root->fs_info, chunk_offset,
7131                            chunk_offset + size);
7132
7133         free_excluded_extents(root, cache);
7134
7135         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7136                                 &cache->space_info);
7137         BUG_ON(ret);
7138
7139         spin_lock(&cache->space_info->lock);
7140         cache->space_info->bytes_readonly += cache->bytes_super;
7141         spin_unlock(&cache->space_info->lock);
7142
7143         __link_block_group(cache->space_info, cache);
7144
7145         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7146         BUG_ON(ret);
7147
7148         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7149                                 sizeof(cache->item));
7150         BUG_ON(ret);
7151
7152         set_avail_alloc_bits(extent_root->fs_info, type);
7153
7154         return 0;
7155 }
7156
7157 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7158                              struct btrfs_root *root, u64 group_start)
7159 {
7160         struct btrfs_path *path;
7161         struct btrfs_block_group_cache *block_group;
7162         struct btrfs_free_cluster *cluster;
7163         struct btrfs_root *tree_root = root->fs_info->tree_root;
7164         struct btrfs_key key;
7165         struct inode *inode;
7166         int ret;
7167         int factor;
7168
7169         root = root->fs_info->extent_root;
7170
7171         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7172         BUG_ON(!block_group);
7173         BUG_ON(!block_group->ro);
7174
7175         /*
7176          * Free the reserved super bytes from this block group before
7177          * remove it.
7178          */
7179         free_excluded_extents(root, block_group);
7180
7181         memcpy(&key, &block_group->key, sizeof(key));
7182         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7183                                   BTRFS_BLOCK_GROUP_RAID1 |
7184                                   BTRFS_BLOCK_GROUP_RAID10))
7185                 factor = 2;
7186         else
7187                 factor = 1;
7188
7189         /* make sure this block group isn't part of an allocation cluster */
7190         cluster = &root->fs_info->data_alloc_cluster;
7191         spin_lock(&cluster->refill_lock);
7192         btrfs_return_cluster_to_free_space(block_group, cluster);
7193         spin_unlock(&cluster->refill_lock);
7194
7195         /*
7196          * make sure this block group isn't part of a metadata
7197          * allocation cluster
7198          */
7199         cluster = &root->fs_info->meta_alloc_cluster;
7200         spin_lock(&cluster->refill_lock);
7201         btrfs_return_cluster_to_free_space(block_group, cluster);
7202         spin_unlock(&cluster->refill_lock);
7203
7204         path = btrfs_alloc_path();
7205         if (!path) {
7206                 ret = -ENOMEM;
7207                 goto out;
7208         }
7209
7210         inode = lookup_free_space_inode(root, block_group, path);
7211         if (!IS_ERR(inode)) {
7212                 ret = btrfs_orphan_add(trans, inode);
7213                 BUG_ON(ret);
7214                 clear_nlink(inode);
7215                 /* One for the block groups ref */
7216                 spin_lock(&block_group->lock);
7217                 if (block_group->iref) {
7218                         block_group->iref = 0;
7219                         block_group->inode = NULL;
7220                         spin_unlock(&block_group->lock);
7221                         iput(inode);
7222                 } else {
7223                         spin_unlock(&block_group->lock);
7224                 }
7225                 /* One for our lookup ref */
7226                 iput(inode);
7227         }
7228
7229         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7230         key.offset = block_group->key.objectid;
7231         key.type = 0;
7232
7233         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7234         if (ret < 0)
7235                 goto out;
7236         if (ret > 0)
7237                 btrfs_release_path(path);
7238         if (ret == 0) {
7239                 ret = btrfs_del_item(trans, tree_root, path);
7240                 if (ret)
7241                         goto out;
7242                 btrfs_release_path(path);
7243         }
7244
7245         spin_lock(&root->fs_info->block_group_cache_lock);
7246         rb_erase(&block_group->cache_node,
7247                  &root->fs_info->block_group_cache_tree);
7248         spin_unlock(&root->fs_info->block_group_cache_lock);
7249
7250         down_write(&block_group->space_info->groups_sem);
7251         /*
7252          * we must use list_del_init so people can check to see if they
7253          * are still on the list after taking the semaphore
7254          */
7255         list_del_init(&block_group->list);
7256         up_write(&block_group->space_info->groups_sem);
7257
7258         if (block_group->cached == BTRFS_CACHE_STARTED)
7259                 wait_block_group_cache_done(block_group);
7260
7261         btrfs_remove_free_space_cache(block_group);
7262
7263         spin_lock(&block_group->space_info->lock);
7264         block_group->space_info->total_bytes -= block_group->key.offset;
7265         block_group->space_info->bytes_readonly -= block_group->key.offset;
7266         block_group->space_info->disk_total -= block_group->key.offset * factor;
7267         spin_unlock(&block_group->space_info->lock);
7268
7269         memcpy(&key, &block_group->key, sizeof(key));
7270
7271         btrfs_clear_space_info_full(root->fs_info);
7272
7273         btrfs_put_block_group(block_group);
7274         btrfs_put_block_group(block_group);
7275
7276         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7277         if (ret > 0)
7278                 ret = -EIO;
7279         if (ret < 0)
7280                 goto out;
7281
7282         ret = btrfs_del_item(trans, root, path);
7283 out:
7284         btrfs_free_path(path);
7285         return ret;
7286 }
7287
7288 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7289 {
7290         struct btrfs_space_info *space_info;
7291         struct btrfs_super_block *disk_super;
7292         u64 features;
7293         u64 flags;
7294         int mixed = 0;
7295         int ret;
7296
7297         disk_super = &fs_info->super_copy;
7298         if (!btrfs_super_root(disk_super))
7299                 return 1;
7300
7301         features = btrfs_super_incompat_flags(disk_super);
7302         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7303                 mixed = 1;
7304
7305         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7306         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7307         if (ret)
7308                 goto out;
7309
7310         if (mixed) {
7311                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7312                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7313         } else {
7314                 flags = BTRFS_BLOCK_GROUP_METADATA;
7315                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7316                 if (ret)
7317                         goto out;
7318
7319                 flags = BTRFS_BLOCK_GROUP_DATA;
7320                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7321         }
7322 out:
7323         return ret;
7324 }
7325
7326 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7327 {
7328         return unpin_extent_range(root, start, end);
7329 }
7330
7331 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7332                                u64 num_bytes, u64 *actual_bytes)
7333 {
7334         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7335 }
7336
7337 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7338 {
7339         struct btrfs_fs_info *fs_info = root->fs_info;
7340         struct btrfs_block_group_cache *cache = NULL;
7341         u64 group_trimmed;
7342         u64 start;
7343         u64 end;
7344         u64 trimmed = 0;
7345         int ret = 0;
7346
7347         cache = btrfs_lookup_block_group(fs_info, range->start);
7348
7349         while (cache) {
7350                 if (cache->key.objectid >= (range->start + range->len)) {
7351                         btrfs_put_block_group(cache);
7352                         break;
7353                 }
7354
7355                 start = max(range->start, cache->key.objectid);
7356                 end = min(range->start + range->len,
7357                                 cache->key.objectid + cache->key.offset);
7358
7359                 if (end - start >= range->minlen) {
7360                         if (!block_group_cache_done(cache)) {
7361                                 ret = cache_block_group(cache, NULL, root, 0);
7362                                 if (!ret)
7363                                         wait_block_group_cache_done(cache);
7364                         }
7365                         ret = btrfs_trim_block_group(cache,
7366                                                      &group_trimmed,
7367                                                      start,
7368                                                      end,
7369                                                      range->minlen);
7370
7371                         trimmed += group_trimmed;
7372                         if (ret) {
7373                                 btrfs_put_block_group(cache);
7374                                 break;
7375                         }
7376                 }
7377
7378                 cache = next_block_group(fs_info->tree_root, cache);
7379         }
7380
7381         range->len = trimmed;
7382         return ret;
7383 }