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