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
  19 #include <linux/sched.h>
  20 #include <linux/crc32c.h>
  21 #include <linux/pagemap.h>
  22 #include "hash.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "print-tree.h"
  26 #include "transaction.h"
  27 #include "volumes.h"
  28
  29 #define BLOCK_GROUP_DATA     EXTENT_WRITEBACK
  30 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
  31 #define BLOCK_GROUP_SYSTEM   EXTENT_NEW
  32
  33 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
  34
  35 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  36                                  btrfs_root *extent_root);
  37 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  38                                btrfs_root *extent_root);
  39 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
  40                            struct btrfs_root *root, u64 bytes_used,
  41                            u64 type, u64 chunk_tree, u64 chunk_objectid,
  42                            u64 size);
  43
  44
  45 static int cache_block_group(struct btrfs_root *root,
  46                              struct btrfs_block_group_cache *block_group)
  47 {
  48         struct btrfs_path *path;
  49         int ret;
  50         struct btrfs_key key;
  51         struct extent_buffer *leaf;
  52         struct extent_io_tree *free_space_cache;
  53         int slot;
  54         u64 last = 0;
  55         u64 hole_size;
  56         u64 first_free;
  57         int found = 0;
  58
  59         if (!block_group)
  60                 return 0;
  61
  62         root = root->fs_info->extent_root;
  63         free_space_cache = &root->fs_info->free_space_cache;
  64
  65         if (block_group->cached)
  66                 return 0;
  67
  68         path = btrfs_alloc_path();
  69         if (!path)
  70                 return -ENOMEM;
  71
  72         path->reada = 2;
  73         first_free = block_group->key.objectid;
  74         key.objectid = block_group->key.objectid;
  75         key.offset = 0;
  76         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
  77         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  78         if (ret < 0)
  79                 return ret;
  80         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
  81         if (ret < 0)
  82                 return ret;
  83         if (ret == 0) {
  84                 leaf = path->nodes[0];
  85                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
  86                 if (key.objectid + key.offset > first_free)
  87                         first_free = key.objectid + key.offset;
  88         }
  89         while(1) {
  90                 leaf = path->nodes[0];
  91                 slot = path->slots[0];
  92                 if (slot >= btrfs_header_nritems(leaf)) {
  93                         ret = btrfs_next_leaf(root, path);
  94                         if (ret < 0)
  95                                 goto err;
  96                         if (ret == 0) {
  97                                 continue;
  98                         } else {
  99                                 break;
 100                         }
 101                 }
 102                 btrfs_item_key_to_cpu(leaf, &key, slot);
 103                 if (key.objectid < block_group->key.objectid) {
 104                         goto next;
 105                 }
 106                 if (key.objectid >= block_group->key.objectid +
 107                     block_group->key.offset) {
 108                         break;
 109                 }
 110
 111                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 112                         if (!found) {
 113                                 last = first_free;
 114                                 found = 1;
 115                         }
 116                         if (key.objectid > last) {
 117                                 hole_size = key.objectid - last;
 118                                 set_extent_dirty(free_space_cache, last,
 119                                                  last + hole_size - 1,
 120                                                  GFP_NOFS);
 121                         }
 122                         last = key.objectid + key.offset;
 123                 }
 124 next:
 125                 path->slots[0]++;
 126         }
 127
 128         if (!found)
 129                 last = first_free;
 130         if (block_group->key.objectid +
 131             block_group->key.offset > last) {
 132                 hole_size = block_group->key.objectid +
 133                         block_group->key.offset - last;
 134                 set_extent_dirty(free_space_cache, last,
 135                                  last + hole_size - 1, GFP_NOFS);
 136         }
 137         block_group->cached = 1;
 138 err:
 139         btrfs_free_path(path);
 140         return 0;
 141 }
 142
 143 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 144                                                          btrfs_fs_info *info,
 145                                                          u64 bytenr)
 146 {
 147         struct extent_io_tree *block_group_cache;
 148         struct btrfs_block_group_cache *block_group = NULL;
 149         u64 ptr;
 150         u64 start;
 151         u64 end;
 152         int ret;
 153
 154         block_group_cache = &info->block_group_cache;
 155         ret = find_first_extent_bit(block_group_cache,
 156                                     bytenr, &start, &end,
 157                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 158                                     BLOCK_GROUP_SYSTEM);
 159         if (ret) {
 160                 return NULL;
 161         }
 162         ret = get_state_private(block_group_cache, start, &ptr);
 163         if (ret)
 164                 return NULL;
 165
 166         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 167         if (block_group->key.objectid <= bytenr && bytenr <
 168             block_group->key.objectid + block_group->key.offset)
 169                 return block_group;
 170         return NULL;
 171 }
 172
 173 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 174 {
 175         return (cache->flags & bits);
 176 }
 177
 178 static int noinline find_search_start(struct btrfs_root *root,
 179                               struct btrfs_block_group_cache **cache_ret,
 180                               u64 *start_ret, int num, int data)
 181 {
 182         int ret;
 183         struct btrfs_block_group_cache *cache = *cache_ret;
 184         struct extent_io_tree *free_space_cache;
 185         struct extent_state *state;
 186         u64 last;
 187         u64 start = 0;
 188         u64 cache_miss = 0;
 189         u64 total_fs_bytes;
 190         u64 search_start = *start_ret;
 191         int wrapped = 0;
 192
 193         if (!cache)
 194                 goto out;
 195         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 196         free_space_cache = &root->fs_info->free_space_cache;
 197
 198 again:
 199         ret = cache_block_group(root, cache);
 200         if (ret)
 201                 goto out;
 202
 203         last = max(search_start, cache->key.objectid);
 204         if (!block_group_bits(cache, data)) {
 205                 goto new_group;
 206         }
 207
 208         spin_lock_irq(&free_space_cache->lock);
 209         state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
 210         while(1) {
 211                 if (!state) {
 212                         if (!cache_miss)
 213                                 cache_miss = last;
 214                         spin_unlock_irq(&free_space_cache->lock);
 215                         goto new_group;
 216                 }
 217
 218                 start = max(last, state->start);
 219                 last = state->end + 1;
 220                 if (last - start < num) {
 221                         if (last == cache->key.objectid + cache->key.offset)
 222                                 cache_miss = start;
 223                         do {
 224                                 state = extent_state_next(state);
 225                         } while(state && !(state->state & EXTENT_DIRTY));
 226                         continue;
 227                 }
 228                 spin_unlock_irq(&free_space_cache->lock);
 229                 if (start + num > cache->key.objectid + cache->key.offset)
 230                         goto new_group;
 231                 if (start + num  > total_fs_bytes)
 232                         goto new_group;
 233                 *start_ret = start;
 234                 return 0;
 235         } out:
 236         cache = btrfs_lookup_block_group(root->fs_info, search_start);
 237         if (!cache) {
 238                 printk("Unable to find block group for %Lu\n", search_start);
 239                 WARN_ON(1);
 240         }
 241         return -ENOSPC;
 242
 243 new_group:
 244         last = cache->key.objectid + cache->key.offset;
 245 wrapped:
 246         cache = btrfs_lookup_block_group(root->fs_info, last);
 247         if (!cache || cache->key.objectid >= total_fs_bytes) {
 248 no_cache:
 249                 if (!wrapped) {
 250                         wrapped = 1;
 251                         last = search_start;
 252                         goto wrapped;
 253                 }
 254                 goto out;
 255         }
 256         if (cache_miss && !cache->cached) {
 257                 cache_block_group(root, cache);
 258                 last = cache_miss;
 259                 cache = btrfs_lookup_block_group(root->fs_info, last);
 260         }
 261         cache = btrfs_find_block_group(root, cache, last, data, 0);
 262         if (!cache)
 263                 goto no_cache;
 264         *cache_ret = cache;
 265         cache_miss = 0;
 266         goto again;
 267 }
 268
 269 static u64 div_factor(u64 num, int factor)
 270 {
 271         if (factor == 10)
 272                 return num;
 273         num *= factor;
 274         do_div(num, 10);
 275         return num;
 276 }
 277
 278 static int block_group_state_bits(u64 flags)
 279 {
 280         int bits = 0;
 281         if (flags & BTRFS_BLOCK_GROUP_DATA)
 282                 bits |= BLOCK_GROUP_DATA;
 283         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 284                 bits |= BLOCK_GROUP_METADATA;
 285         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 286                 bits |= BLOCK_GROUP_SYSTEM;
 287         return bits;
 288 }
 289
 290 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 291                                                  struct btrfs_block_group_cache
 292                                                  *hint, u64 search_start,
 293                                                  int data, int owner)
 294 {
 295         struct btrfs_block_group_cache *cache;
 296         struct extent_io_tree *block_group_cache;
 297         struct btrfs_block_group_cache *found_group = NULL;
 298         struct btrfs_fs_info *info = root->fs_info;
 299         u64 used;
 300         u64 last = 0;
 301         u64 hint_last;
 302         u64 start;
 303         u64 end;
 304         u64 free_check;
 305         u64 ptr;
 306         u64 total_fs_bytes;
 307         int bit;
 308         int ret;
 309         int full_search = 0;
 310         int factor = 8;
 311
 312         block_group_cache = &info->block_group_cache;
 313         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 314
 315         if (!owner)
 316                 factor = 8;
 317
 318         bit = block_group_state_bits(data);
 319
 320         if (search_start && search_start < total_fs_bytes) {
 321                 struct btrfs_block_group_cache *shint;
 322                 shint = btrfs_lookup_block_group(info, search_start);
 323                 if (shint && block_group_bits(shint, data)) {
 324                         used = btrfs_block_group_used(&shint->item);
 325                         if (used + shint->pinned <
 326                             div_factor(shint->key.offset, factor)) {
 327                                 return shint;
 328                         }
 329                 }
 330         }
 331         if (hint && block_group_bits(hint, data) &&
 332             hint->key.objectid < total_fs_bytes) {
 333                 used = btrfs_block_group_used(&hint->item);
 334                 if (used + hint->pinned <
 335                     div_factor(hint->key.offset, factor)) {
 336                         return hint;
 337                 }
 338                 last = hint->key.objectid + hint->key.offset;
 339                 hint_last = last;
 340         } else {
 341                 if (hint)
 342                         hint_last = max(hint->key.objectid, search_start);
 343                 else
 344                         hint_last = search_start;
 345
 346                 if (hint_last >= total_fs_bytes)
 347                         hint_last = search_start;
 348                 last = hint_last;
 349         }
 350 again:
 351         while(1) {
 352                 ret = find_first_extent_bit(block_group_cache, last,
 353                                             &start, &end, bit);
 354                 if (ret)
 355                         break;
 356
 357                 ret = get_state_private(block_group_cache, start, &ptr);
 358                 if (ret)
 359                         break;
 360
 361                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 362                 last = cache->key.objectid + cache->key.offset;
 363                 used = btrfs_block_group_used(&cache->item);
 364
 365                 if (cache->key.objectid > total_fs_bytes)
 366                         break;
 367
 368                 if (full_search)
 369                         free_check = cache->key.offset;
 370                 else
 371                         free_check = div_factor(cache->key.offset, factor);
 372
 373                 if (used + cache->pinned < free_check) {
 374                         found_group = cache;
 375                         goto found;
 376                 }
 377                 if (full_search) {
 378                         printk("failed on cache %Lu used %Lu total %Lu\n",
 379                                cache->key.objectid, used, cache->key.offset);
 380                 }
 381                 cond_resched();
 382         }
 383         if (!full_search) {
 384                 last = search_start;
 385                 full_search = 1;
 386                 goto again;
 387         }
 388 found:
 389         return found_group;
 390 }
 391
 392 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
 393                            u64 owner, u64 owner_offset)
 394 {
 395         u32 high_crc = ~(u32)0;
 396         u32 low_crc = ~(u32)0;
 397         __le64 lenum;
 398
 399         lenum = cpu_to_le64(root_objectid);
 400         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 401         lenum = cpu_to_le64(ref_generation);
 402         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 403         if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
 404                 lenum = cpu_to_le64(owner);
 405                 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 406                 lenum = cpu_to_le64(owner_offset);
 407                 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 408         }
 409         return ((u64)high_crc << 32) | (u64)low_crc;
 410 }
 411
 412 static int match_extent_ref(struct extent_buffer *leaf,
 413                             struct btrfs_extent_ref *disk_ref,
 414                             struct btrfs_extent_ref *cpu_ref)
 415 {
 416         int ret;
 417         int len;
 418
 419         if (cpu_ref->objectid)
 420                 len = sizeof(*cpu_ref);
 421         else
 422                 len = 2 * sizeof(u64);
 423         ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
 424                                    len);
 425         return ret == 0;
 426 }
 427
 428 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
 429                                           struct btrfs_root *root,
 430                                           struct btrfs_path *path, u64 bytenr,
 431                                           u64 root_objectid,
 432                                           u64 ref_generation, u64 owner,
 433                                           u64 owner_offset, int del)
 434 {
 435         u64 hash;
 436         struct btrfs_key key;
 437         struct btrfs_key found_key;
 438         struct btrfs_extent_ref ref;
 439         struct extent_buffer *leaf;
 440         struct btrfs_extent_ref *disk_ref;
 441         int ret;
 442         int ret2;
 443
 444         btrfs_set_stack_ref_root(&ref, root_objectid);
 445         btrfs_set_stack_ref_generation(&ref, ref_generation);
 446         btrfs_set_stack_ref_objectid(&ref, owner);
 447         btrfs_set_stack_ref_offset(&ref, owner_offset);
 448
 449         hash = hash_extent_ref(root_objectid, ref_generation, owner,
 450                                owner_offset);
 451         key.offset = hash;
 452         key.objectid = bytenr;
 453         key.type = BTRFS_EXTENT_REF_KEY;
 454
 455         while (1) {
 456                 ret = btrfs_search_slot(trans, root, &key, path,
 457                                         del ? -1 : 0, del);
 458                 if (ret < 0)
 459                         goto out;
 460                 leaf = path->nodes[0];
 461                 if (ret != 0) {
 462                         u32 nritems = btrfs_header_nritems(leaf);
 463                         if (path->slots[0] >= nritems) {
 464                                 ret2 = btrfs_next_leaf(root, path);
 465                                 if (ret2)
 466                                         goto out;
 467                                 leaf = path->nodes[0];
 468                         }
 469                         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 470                         if (found_key.objectid != bytenr ||
 471                             found_key.type != BTRFS_EXTENT_REF_KEY)
 472                                 goto out;
 473                         key.offset = found_key.offset;
 474                         if (del) {
 475                                 btrfs_release_path(root, path);
 476                                 continue;
 477                         }
 478                 }
 479                 disk_ref = btrfs_item_ptr(path->nodes[0],
 480                                           path->slots[0],
 481                                           struct btrfs_extent_ref);
 482                 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
 483                         ret = 0;
 484                         goto out;
 485                 }
 486                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 487                 key.offset = found_key.offset + 1;
 488                 btrfs_release_path(root, path);
 489         }
 490 out:
 491         return ret;
 492 }
 493
 494 /*
 495  * Back reference rules.  Back refs have three main goals:
 496  *
 497  * 1) differentiate between all holders of references to an extent so that
 498  *    when a reference is dropped we can make sure it was a valid reference
 499  *    before freeing the extent.
 500  *
 501  * 2) Provide enough information to quickly find the holders of an extent
 502  *    if we notice a given block is corrupted or bad.
 503  *
 504  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 505  *    maintenance.  This is actually the same as #2, but with a slightly
 506  *    different use case.
 507  *
 508  * File extents can be referenced by:
 509  *
 510  * - multiple snapshots, subvolumes, or different generations in one subvol
 511  * - different files inside a single subvolume (in theory, not implemented yet)
 512  * - different offsets inside a file (bookend extents in file.c)
 513  *
 514  * The extent ref structure has fields for:
 515  *
 516  * - Objectid of the subvolume root
 517  * - Generation number of the tree holding the reference
 518  * - objectid of the file holding the reference
 519  * - offset in the file corresponding to the key holding the reference
 520  *
 521  * When a file extent is allocated the fields are filled in:
 522  *     (root_key.objectid, trans->transid, inode objectid, offset in file)
 523  *
 524  * When a leaf is cow'd new references are added for every file extent found
 525  * in the leaf.  It looks the same as the create case, but trans->transid
 526  * will be different when the block is cow'd.
 527  *
 528  *     (root_key.objectid, trans->transid, inode objectid, offset in file)
 529  *
 530  * When a file extent is removed either during snapshot deletion or file
 531  * truncation, the corresponding back reference is found
 532  * by searching for:
 533  *
 534  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 535  *      inode objectid, offset in file)
 536  *
 537  * Btree extents can be referenced by:
 538  *
 539  * - Different subvolumes
 540  * - Different generations of the same subvolume
 541  *
 542  * Storing sufficient information for a full reverse mapping of a btree
 543  * block would require storing the lowest key of the block in the backref,
 544  * and it would require updating that lowest key either before write out or
 545  * every time it changed.  Instead, the objectid of the lowest key is stored
 546  * along with the level of the tree block.  This provides a hint
 547  * about where in the btree the block can be found.  Searches through the
 548  * btree only need to look for a pointer to that block, so they stop one
 549  * level higher than the level recorded in the backref.
 550  *
 551  * Some btrees do not do reference counting on their extents.  These
 552  * include the extent tree and the tree of tree roots.  Backrefs for these
 553  * trees always have a generation of zero.
 554  *
 555  * When a tree block is created, back references are inserted:
 556  *
 557  * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
 558  *
 559  * When a tree block is cow'd in a reference counted root,
 560  * new back references are added for all the blocks it points to.
 561  * These are of the form (trans->transid will have increased since creation):
 562  *
 563  * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
 564  *
 565  * Because the lowest_key_objectid and the level are just hints
 566  * they are not used when backrefs are deleted.  When a backref is deleted:
 567  *
 568  * if backref was for a tree root:
 569  *     root_objectid = root->root_key.objectid
 570  * else
 571  *     root_objectid = btrfs_header_owner(parent)
 572  *
 573  * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
 574  *
 575  * Back Reference Key hashing:
 576  *
 577  * Back references have four fields, each 64 bits long.  Unfortunately,
 578  * This is hashed into a single 64 bit number and placed into the key offset.
 579  * The key objectid corresponds to the first byte in the extent, and the
 580  * key type is set to BTRFS_EXTENT_REF_KEY
 581  */
 582 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
 583                                  struct btrfs_root *root,
 584                                  struct btrfs_path *path, u64 bytenr,
 585                                  u64 root_objectid, u64 ref_generation,
 586                                  u64 owner, u64 owner_offset)
 587 {
 588         u64 hash;
 589         struct btrfs_key key;
 590         struct btrfs_extent_ref ref;
 591         struct btrfs_extent_ref *disk_ref;
 592         int ret;
 593
 594         btrfs_set_stack_ref_root(&ref, root_objectid);
 595         btrfs_set_stack_ref_generation(&ref, ref_generation);
 596         btrfs_set_stack_ref_objectid(&ref, owner);
 597         btrfs_set_stack_ref_offset(&ref, owner_offset);
 598
 599         hash = hash_extent_ref(root_objectid, ref_generation, owner,
 600                                owner_offset);
 601         key.offset = hash;
 602         key.objectid = bytenr;
 603         key.type = BTRFS_EXTENT_REF_KEY;
 604
 605         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
 606         while (ret == -EEXIST) {
 607                 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 608                                           struct btrfs_extent_ref);
 609                 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
 610                         goto out;
 611                 key.offset++;
 612                 btrfs_release_path(root, path);
 613                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 614                                               sizeof(ref));
 615         }
 616         if (ret)
 617                 goto out;
 618         disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 619                                   struct btrfs_extent_ref);
 620         write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
 621                             sizeof(ref));
 622         btrfs_mark_buffer_dirty(path->nodes[0]);
 623 out:
 624         btrfs_release_path(root, path);
 625         return ret;
 626 }
 627
 628 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 629                                 struct btrfs_root *root,
 630                                 u64 bytenr, u64 num_bytes,
 631                                 u64 root_objectid, u64 ref_generation,
 632                                 u64 owner, u64 owner_offset)
 633 {
 634         struct btrfs_path *path;
 635         int ret;
 636         struct btrfs_key key;
 637         struct extent_buffer *l;
 638         struct btrfs_extent_item *item;
 639         u32 refs;
 640
 641         WARN_ON(num_bytes < root->sectorsize);
 642         path = btrfs_alloc_path();
 643         if (!path)
 644                 return -ENOMEM;
 645
 646         path->reada = 0;
 647         key.objectid = bytenr;
 648         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 649         key.offset = num_bytes;
 650         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 651                                 0, 1);
 652         if (ret < 0)
 653                 return ret;
 654         if (ret != 0) {
 655                 BUG();
 656         }
 657         BUG_ON(ret != 0);
 658         l = path->nodes[0];
 659         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 660         refs = btrfs_extent_refs(l, item);
 661         btrfs_set_extent_refs(l, item, refs + 1);
 662         btrfs_mark_buffer_dirty(path->nodes[0]);
 663
 664         btrfs_release_path(root->fs_info->extent_root, path);
 665
 666         path->reada = 0;
 667         ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
 668                                           path, bytenr, root_objectid,
 669                                           ref_generation, owner, owner_offset);
 670         BUG_ON(ret);
 671         finish_current_insert(trans, root->fs_info->extent_root);
 672         del_pending_extents(trans, root->fs_info->extent_root);
 673
 674         btrfs_free_path(path);
 675         return 0;
 676 }
 677
 678 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
 679                          struct btrfs_root *root)
 680 {
 681         finish_current_insert(trans, root->fs_info->extent_root);
 682         del_pending_extents(trans, root->fs_info->extent_root);
 683         return 0;
 684 }
 685
 686 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
 687                              struct btrfs_root *root, u64 bytenr,
 688                              u64 num_bytes, u32 *refs)
 689 {
 690         struct btrfs_path *path;
 691         int ret;
 692         struct btrfs_key key;
 693         struct extent_buffer *l;
 694         struct btrfs_extent_item *item;
 695
 696         WARN_ON(num_bytes < root->sectorsize);
 697         path = btrfs_alloc_path();
 698         path->reada = 0;
 699         key.objectid = bytenr;
 700         key.offset = num_bytes;
 701         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 702         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 703                                 0, 0);
 704         if (ret < 0)
 705                 goto out;
 706         if (ret != 0) {
 707                 btrfs_print_leaf(root, path->nodes[0]);
 708                 printk("failed to find block number %Lu\n", bytenr);
 709                 BUG();
 710         }
 711         l = path->nodes[0];
 712         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 713         *refs = btrfs_extent_refs(l, item);
 714 out:
 715         btrfs_free_path(path);
 716         return 0;
 717 }
 718
 719 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
 720                                   struct btrfs_path *count_path,
 721                                   u64 first_extent)
 722 {
 723         struct btrfs_root *extent_root = root->fs_info->extent_root;
 724         struct btrfs_path *path;
 725         u64 bytenr;
 726         u64 found_objectid;
 727         u64 root_objectid = root->root_key.objectid;
 728         u32 total_count = 0;
 729         u32 cur_count;
 730         u32 nritems;
 731         int ret;
 732         struct btrfs_key key;
 733         struct btrfs_key found_key;
 734         struct extent_buffer *l;
 735         struct btrfs_extent_item *item;
 736         struct btrfs_extent_ref *ref_item;
 737         int level = -1;
 738
 739         path = btrfs_alloc_path();
 740 again:
 741         if (level == -1)
 742                 bytenr = first_extent;
 743         else
 744                 bytenr = count_path->nodes[level]->start;
 745
 746         cur_count = 0;
 747         key.objectid = bytenr;
 748         key.offset = 0;
 749
 750         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 751         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 752         if (ret < 0)
 753                 goto out;
 754         BUG_ON(ret == 0);
 755
 756         l = path->nodes[0];
 757         btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
 758
 759         if (found_key.objectid != bytenr ||
 760             found_key.type != BTRFS_EXTENT_ITEM_KEY) {
 761                 goto out;
 762         }
 763
 764         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 765         while (1) {
 766                 l = path->nodes[0];
 767                 nritems = btrfs_header_nritems(l);
 768                 if (path->slots[0] >= nritems) {
 769                         ret = btrfs_next_leaf(extent_root, path);
 770                         if (ret == 0)
 771                                 continue;
 772                         break;
 773                 }
 774                 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
 775                 if (found_key.objectid != bytenr)
 776                         break;
 777
 778                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
 779                         path->slots[0]++;
 780                         continue;
 781                 }
 782
 783                 cur_count++;
 784                 ref_item = btrfs_item_ptr(l, path->slots[0],
 785                                           struct btrfs_extent_ref);
 786                 found_objectid = btrfs_ref_root(l, ref_item);
 787
 788                 if (found_objectid != root_objectid) {
 789                         total_count = 2;
 790                         goto out;
 791                 }
 792                 total_count = 1;
 793                 path->slots[0]++;
 794         }
 795         if (cur_count == 0) {
 796                 total_count = 0;
 797                 goto out;
 798         }
 799         if (level >= 0 && root->node == count_path->nodes[level])
 800                 goto out;
 801         level++;
 802         btrfs_release_path(root, path);
 803         goto again;
 804
 805 out:
 806         btrfs_free_path(path);
 807         return total_count;
 808 }
 809 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
 810                        struct btrfs_root *root, u64 owner_objectid)
 811 {
 812         u64 generation;
 813         u64 key_objectid;
 814         u64 level;
 815         u32 nritems;
 816         struct btrfs_disk_key disk_key;
 817
 818         level = btrfs_header_level(root->node);
 819         generation = trans->transid;
 820         nritems = btrfs_header_nritems(root->node);
 821         if (nritems > 0) {
 822                 if (level == 0)
 823                         btrfs_item_key(root->node, &disk_key, 0);
 824                 else
 825                         btrfs_node_key(root->node, &disk_key, 0);
 826                 key_objectid = btrfs_disk_key_objectid(&disk_key);
 827         } else {
 828                 key_objectid = 0;
 829         }
 830         return btrfs_inc_extent_ref(trans, root, root->node->start,
 831                                     root->node->len, owner_objectid,
 832                                     generation, level, key_objectid);
 833 }
 834
 835 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 836                   struct extent_buffer *buf)
 837 {
 838         u64 bytenr;
 839         u32 nritems;
 840         struct btrfs_key key;
 841         struct btrfs_file_extent_item *fi;
 842         int i;
 843         int level;
 844         int ret;
 845         int faili;
 846
 847         if (!root->ref_cows)
 848                 return 0;
 849
 850         level = btrfs_header_level(buf);
 851         nritems = btrfs_header_nritems(buf);
 852         for (i = 0; i < nritems; i++) {
 853                 if (level == 0) {
 854                         u64 disk_bytenr;
 855                         btrfs_item_key_to_cpu(buf, &key, i);
 856                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
 857                                 continue;
 858                         fi = btrfs_item_ptr(buf, i,
 859                                             struct btrfs_file_extent_item);
 860                         if (btrfs_file_extent_type(buf, fi) ==
 861                             BTRFS_FILE_EXTENT_INLINE)
 862                                 continue;
 863                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
 864                         if (disk_bytenr == 0)
 865                                 continue;
 866                         ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
 867                                     btrfs_file_extent_disk_num_bytes(buf, fi),
 868                                     root->root_key.objectid, trans->transid,
 869                                     key.objectid, key.offset);
 870                         if (ret) {
 871                                 faili = i;
 872                                 goto fail;
 873                         }
 874                 } else {
 875                         bytenr = btrfs_node_blockptr(buf, i);
 876                         btrfs_node_key_to_cpu(buf, &key, i);
 877                         ret = btrfs_inc_extent_ref(trans, root, bytenr,
 878                                            btrfs_level_size(root, level - 1),
 879                                            root->root_key.objectid,
 880                                            trans->transid,
 881                                            level - 1, key.objectid);
 882                         if (ret) {
 883                                 faili = i;
 884                                 goto fail;
 885                         }
 886                 }
 887         }
 888         return 0;
 889 fail:
 890         WARN_ON(1);
 891 #if 0
 892         for (i =0; i < faili; i++) {
 893                 if (level == 0) {
 894                         u64 disk_bytenr;
 895                         btrfs_item_key_to_cpu(buf, &key, i);
 896                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
 897                                 continue;
 898                         fi = btrfs_item_ptr(buf, i,
 899                                             struct btrfs_file_extent_item);
 900                         if (btrfs_file_extent_type(buf, fi) ==
 901                             BTRFS_FILE_EXTENT_INLINE)
 902                                 continue;
 903                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
 904                         if (disk_bytenr == 0)
 905                                 continue;
 906                         err = btrfs_free_extent(trans, root, disk_bytenr,
 907                                     btrfs_file_extent_disk_num_bytes(buf,
 908                                                                       fi), 0);
 909                         BUG_ON(err);
 910                 } else {
 911                         bytenr = btrfs_node_blockptr(buf, i);
 912                         err = btrfs_free_extent(trans, root, bytenr,
 913                                         btrfs_level_size(root, level - 1), 0);
 914                         BUG_ON(err);
 915                 }
 916         }
 917 #endif
 918         return ret;
 919 }
 920
 921 static int write_one_cache_group(struct btrfs_trans_handle *trans,
 922                                  struct btrfs_root *root,
 923                                  struct btrfs_path *path,
 924                                  struct btrfs_block_group_cache *cache)
 925 {
 926         int ret;
 927         int pending_ret;
 928         struct btrfs_root *extent_root = root->fs_info->extent_root;
 929         unsigned long bi;
 930         struct extent_buffer *leaf;
 931
 932         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
 933         if (ret < 0)
 934                 goto fail;
 935         BUG_ON(ret);
 936
 937         leaf = path->nodes[0];
 938         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
 939         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
 940         btrfs_mark_buffer_dirty(leaf);
 941         btrfs_release_path(extent_root, path);
 942 fail:
 943         finish_current_insert(trans, extent_root);
 944         pending_ret = del_pending_extents(trans, extent_root);
 945         if (ret)
 946                 return ret;
 947         if (pending_ret)
 948                 return pending_ret;
 949         return 0;
 950
 951 }
 952
 953 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 954                                    struct btrfs_root *root)
 955 {
 956         struct extent_io_tree *block_group_cache;
 957         struct btrfs_block_group_cache *cache;
 958         int ret;
 959         int err = 0;
 960         int werr = 0;
 961         struct btrfs_path *path;
 962         u64 last = 0;
 963         u64 start;
 964         u64 end;
 965         u64 ptr;
 966
 967         block_group_cache = &root->fs_info->block_group_cache;
 968         path = btrfs_alloc_path();
 969         if (!path)
 970                 return -ENOMEM;
 971
 972         while(1) {
 973                 ret = find_first_extent_bit(block_group_cache, last,
 974                                             &start, &end, BLOCK_GROUP_DIRTY);
 975                 if (ret)
 976                         break;
 977
 978                 last = end + 1;
 979                 ret = get_state_private(block_group_cache, start, &ptr);
 980                 if (ret)
 981                         break;
 982
 983                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 984                 err = write_one_cache_group(trans, root,
 985                                             path, cache);
 986                 /*
 987                  * if we fail to write the cache group, we want
 988                  * to keep it marked dirty in hopes that a later
 989                  * write will work
 990                  */
 991                 if (err) {
 992                         werr = err;
 993                         continue;
 994                 }
 995                 clear_extent_bits(block_group_cache, start, end,
 996                                   BLOCK_GROUP_DIRTY, GFP_NOFS);
 997         }
 998         btrfs_free_path(path);
 999         return werr;
1000 }
1001
1002 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1003                                                   u64 flags)
1004 {
1005         struct list_head *head = &info->space_info;
1006         struct list_head *cur;
1007         struct btrfs_space_info *found;
1008         list_for_each(cur, head) {
1009                 found = list_entry(cur, struct btrfs_space_info, list);
1010                 if (found->flags == flags)
1011                         return found;
1012         }
1013         return NULL;
1014
1015 }
1016
1017 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1018                           struct btrfs_root *extent_root, u64 alloc_bytes,
1019                           u64 flags)
1020 {
1021         struct btrfs_space_info *space_info;
1022         u64 thresh;
1023         u64 start;
1024         u64 num_bytes;
1025         int ret;
1026
1027         space_info = __find_space_info(extent_root->fs_info, flags);
1028         BUG_ON(!space_info);
1029
1030         if (space_info->full)
1031                 return 0;
1032
1033         thresh = div_factor(space_info->total_bytes, 7);
1034         if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1035             thresh)
1036                 return 0;
1037
1038         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1039         if (ret == -ENOSPC) {
1040 printk("space info full %Lu\n", flags);
1041                 space_info->full = 1;
1042                 return 0;
1043         }
1044
1045         BUG_ON(ret);
1046
1047         ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1048                      extent_root->fs_info->chunk_root->root_key.objectid,
1049                      start, num_bytes);
1050         BUG_ON(ret);
1051         return 0;
1052 }
1053
1054 static int update_block_group(struct btrfs_trans_handle *trans,
1055                               struct btrfs_root *root,
1056                               u64 bytenr, u64 num_bytes, int alloc,
1057                               int mark_free)
1058 {
1059         struct btrfs_block_group_cache *cache;
1060         struct btrfs_fs_info *info = root->fs_info;
1061         u64 total = num_bytes;
1062         u64 old_val;
1063         u64 byte_in_group;
1064         u64 start;
1065         u64 end;
1066
1067         while(total) {
1068                 cache = btrfs_lookup_block_group(info, bytenr);
1069                 if (!cache) {
1070                         return -1;
1071                 }
1072                 byte_in_group = bytenr - cache->key.objectid;
1073                 WARN_ON(byte_in_group > cache->key.offset);
1074                 start = cache->key.objectid;
1075                 end = start + cache->key.offset - 1;
1076                 set_extent_bits(&info->block_group_cache, start, end,
1077                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1078
1079                 old_val = btrfs_block_group_used(&cache->item);
1080                 num_bytes = min(total, cache->key.offset - byte_in_group);
1081                 if (alloc) {
1082                         old_val += num_bytes;
1083                         cache->space_info->bytes_used += num_bytes;
1084                 } else {
1085                         old_val -= num_bytes;
1086                         cache->space_info->bytes_used -= num_bytes;
1087                         if (mark_free) {
1088                                 set_extent_dirty(&info->free_space_cache,
1089                                                  bytenr, bytenr + num_bytes - 1,
1090                                                  GFP_NOFS);
1091                         }
1092                 }
1093                 btrfs_set_block_group_used(&cache->item, old_val);
1094                 total -= num_bytes;
1095                 bytenr += num_bytes;
1096         }
1097         return 0;
1098 }
1099
1100 static int update_pinned_extents(struct btrfs_root *root,
1101                                 u64 bytenr, u64 num, int pin)
1102 {
1103         u64 len;
1104         struct btrfs_block_group_cache *cache;
1105         struct btrfs_fs_info *fs_info = root->fs_info;
1106
1107         if (pin) {
1108                 set_extent_dirty(&fs_info->pinned_extents,
1109                                 bytenr, bytenr + num - 1, GFP_NOFS);
1110         } else {
1111                 clear_extent_dirty(&fs_info->pinned_extents,
1112                                 bytenr, bytenr + num - 1, GFP_NOFS);
1113         }
1114         while (num > 0) {
1115                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1116                 WARN_ON(!cache);
1117                 len = min(num, cache->key.offset -
1118                           (bytenr - cache->key.objectid));
1119                 if (pin) {
1120                         cache->pinned += len;
1121                         cache->space_info->bytes_pinned += len;
1122                         fs_info->total_pinned += len;
1123                 } else {
1124                         cache->pinned -= len;
1125                         cache->space_info->bytes_pinned -= len;
1126                         fs_info->total_pinned -= len;
1127                 }
1128                 bytenr += len;
1129                 num -= len;
1130         }
1131         return 0;
1132 }
1133
1134 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1135 {
1136         u64 last = 0;
1137         u64 start;
1138         u64 end;
1139         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1140         int ret;
1141
1142         while(1) {
1143                 ret = find_first_extent_bit(pinned_extents, last,
1144                                             &start, &end, EXTENT_DIRTY);
1145                 if (ret)
1146                         break;
1147                 set_extent_dirty(copy, start, end, GFP_NOFS);
1148                 last = end + 1;
1149         }
1150         return 0;
1151 }
1152
1153 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1154                                struct btrfs_root *root,
1155                                struct extent_io_tree *unpin)
1156 {
1157         u64 start;
1158         u64 end;
1159         int ret;
1160         struct extent_io_tree *free_space_cache;
1161         free_space_cache = &root->fs_info->free_space_cache;
1162
1163         while(1) {
1164                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1165                                             EXTENT_DIRTY);
1166                 if (ret)
1167                         break;
1168                 update_pinned_extents(root, start, end + 1 - start, 0);
1169                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1170                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1171         }
1172         return 0;
1173 }
1174
1175 static int finish_current_insert(struct btrfs_trans_handle *trans,
1176                                  struct btrfs_root *extent_root)
1177 {
1178         u64 start;
1179         u64 end;
1180         struct btrfs_fs_info *info = extent_root->fs_info;
1181         struct extent_buffer *eb;
1182         struct btrfs_path *path;
1183         struct btrfs_key ins;
1184         struct btrfs_disk_key first;
1185         struct btrfs_extent_item extent_item;
1186         int ret;
1187         int level;
1188         int err = 0;
1189
1190         btrfs_set_stack_extent_refs(&extent_item, 1);
1191         btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1192         path = btrfs_alloc_path();
1193
1194         while(1) {
1195                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1196                                             &end, EXTENT_LOCKED);
1197                 if (ret)
1198                         break;
1199
1200                 ins.objectid = start;
1201                 ins.offset = end + 1 - start;
1202                 err = btrfs_insert_item(trans, extent_root, &ins,
1203                                         &extent_item, sizeof(extent_item));
1204                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1205                                   GFP_NOFS);
1206                 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1207                 level = btrfs_header_level(eb);
1208                 if (level == 0) {
1209                         btrfs_item_key(eb, &first, 0);
1210                 } else {
1211                         btrfs_node_key(eb, &first, 0);
1212                 }
1213                 err = btrfs_insert_extent_backref(trans, extent_root, path,
1214                                           start, extent_root->root_key.objectid,
1215                                           0, level,
1216                                           btrfs_disk_key_objectid(&first));
1217                 BUG_ON(err);
1218                 free_extent_buffer(eb);
1219         }
1220         btrfs_free_path(path);
1221         return 0;
1222 }
1223
1224 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1225                           int pending)
1226 {
1227         int err = 0;
1228         struct extent_buffer *buf;
1229
1230         if (!pending) {
1231                 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1232                 if (buf) {
1233                         if (btrfs_buffer_uptodate(buf)) {
1234                                 u64 transid =
1235                                     root->fs_info->running_transaction->transid;
1236                                 u64 header_transid =
1237                                         btrfs_header_generation(buf);
1238                                 if (header_transid == transid) {
1239                                         clean_tree_block(NULL, root, buf);
1240                                         free_extent_buffer(buf);
1241                                         return 1;
1242                                 }
1243                         }
1244                         free_extent_buffer(buf);
1245                 }
1246                 update_pinned_extents(root, bytenr, num_bytes, 1);
1247         } else {
1248                 set_extent_bits(&root->fs_info->pending_del,
1249                                 bytenr, bytenr + num_bytes - 1,
1250                                 EXTENT_LOCKED, GFP_NOFS);
1251         }
1252         BUG_ON(err < 0);
1253         return 0;
1254 }
1255
1256 /*
1257  * remove an extent from the root, returns 0 on success
1258  */
1259 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1260                          *root, u64 bytenr, u64 num_bytes,
1261                          u64 root_objectid, u64 ref_generation,
1262                          u64 owner_objectid, u64 owner_offset, int pin,
1263                          int mark_free)
1264 {
1265         struct btrfs_path *path;
1266         struct btrfs_key key;
1267         struct btrfs_fs_info *info = root->fs_info;
1268         struct btrfs_root *extent_root = info->extent_root;
1269         struct extent_buffer *leaf;
1270         int ret;
1271         int extent_slot = 0;
1272         int found_extent = 0;
1273         int num_to_del = 1;
1274         struct btrfs_extent_item *ei;
1275         u32 refs;
1276
1277         key.objectid = bytenr;
1278         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1279         key.offset = num_bytes;
1280         path = btrfs_alloc_path();
1281         if (!path)
1282                 return -ENOMEM;
1283
1284         path->reada = 0;
1285         ret = lookup_extent_backref(trans, extent_root, path,
1286                                     bytenr, root_objectid,
1287                                     ref_generation,
1288                                     owner_objectid, owner_offset, 1);
1289         if (ret == 0) {
1290                 struct btrfs_key found_key;
1291                 extent_slot = path->slots[0];
1292                 while(extent_slot > 0) {
1293                         extent_slot--;
1294                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1295                                               extent_slot);
1296                         if (found_key.objectid != bytenr)
1297                                 break;
1298                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1299                             found_key.offset == num_bytes) {
1300                                 found_extent = 1;
1301                                 break;
1302                         }
1303                         if (path->slots[0] - extent_slot > 5)
1304                                 break;
1305                 }
1306                 if (!found_extent)
1307                         ret = btrfs_del_item(trans, extent_root, path);
1308         } else {
1309                 btrfs_print_leaf(extent_root, path->nodes[0]);
1310                 WARN_ON(1);
1311                 printk("Unable to find ref byte nr %Lu root %Lu "
1312                        " gen %Lu owner %Lu offset %Lu\n", bytenr,
1313                        root_objectid, ref_generation, owner_objectid,
1314                        owner_offset);
1315         }
1316         if (!found_extent) {
1317                 btrfs_release_path(extent_root, path);
1318                 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1319                 if (ret < 0)
1320                         return ret;
1321                 BUG_ON(ret);
1322                 extent_slot = path->slots[0];
1323         }
1324
1325         leaf = path->nodes[0];
1326         ei = btrfs_item_ptr(leaf, extent_slot,
1327                             struct btrfs_extent_item);
1328         refs = btrfs_extent_refs(leaf, ei);
1329         BUG_ON(refs == 0);
1330         refs -= 1;
1331         btrfs_set_extent_refs(leaf, ei, refs);
1332
1333         btrfs_mark_buffer_dirty(leaf);
1334
1335         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1336                 /* if the back ref and the extent are next to each other
1337                  * they get deleted below in one shot
1338                  */
1339                 path->slots[0] = extent_slot;
1340                 num_to_del = 2;
1341         } else if (found_extent) {
1342                 /* otherwise delete the extent back ref */
1343                 ret = btrfs_del_item(trans, extent_root, path);
1344                 BUG_ON(ret);
1345                 /* if refs are 0, we need to setup the path for deletion */
1346                 if (refs == 0) {
1347                         btrfs_release_path(extent_root, path);
1348                         ret = btrfs_search_slot(trans, extent_root, &key, path,
1349                                                 -1, 1);
1350                         if (ret < 0)
1351                                 return ret;
1352                         BUG_ON(ret);
1353                 }
1354         }
1355
1356         if (refs == 0) {
1357                 u64 super_used;
1358                 u64 root_used;
1359
1360                 if (pin) {
1361                         ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1362                         if (ret > 0)
1363                                 mark_free = 1;
1364                         BUG_ON(ret < 0);
1365                 }
1366
1367                 /* block accounting for super block */
1368                 super_used = btrfs_super_bytes_used(&info->super_copy);
1369                 btrfs_set_super_bytes_used(&info->super_copy,
1370                                            super_used - num_bytes);
1371
1372                 /* block accounting for root item */
1373                 root_used = btrfs_root_used(&root->root_item);
1374                 btrfs_set_root_used(&root->root_item,
1375                                            root_used - num_bytes);
1376                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1377                                       num_to_del);
1378                 if (ret) {
1379                         return ret;
1380                 }
1381                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1382                                          mark_free);
1383                 BUG_ON(ret);
1384         }
1385         btrfs_free_path(path);
1386         finish_current_insert(trans, extent_root);
1387         return ret;
1388 }
1389
1390 /*
1391  * find all the blocks marked as pending in the radix tree and remove
1392  * them from the extent map
1393  */
1394 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1395                                btrfs_root *extent_root)
1396 {
1397         int ret;
1398         int err = 0;
1399         u64 start;
1400         u64 end;
1401         struct extent_io_tree *pending_del;
1402         struct extent_io_tree *pinned_extents;
1403
1404         pending_del = &extent_root->fs_info->pending_del;
1405         pinned_extents = &extent_root->fs_info->pinned_extents;
1406
1407         while(1) {
1408                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1409                                             EXTENT_LOCKED);
1410                 if (ret)
1411                         break;
1412                 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1413                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1414                                   GFP_NOFS);
1415                 ret = __free_extent(trans, extent_root,
1416                                      start, end + 1 - start,
1417                                      extent_root->root_key.objectid,
1418                                      0, 0, 0, 0, 0);
1419                 if (ret)
1420                         err = ret;
1421         }
1422         return err;
1423 }
1424
1425 /*
1426  * remove an extent from the root, returns 0 on success
1427  */
1428 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1429                       *root, u64 bytenr, u64 num_bytes,
1430                       u64 root_objectid, u64 ref_generation,
1431                       u64 owner_objectid, u64 owner_offset, int pin)
1432 {
1433         struct btrfs_root *extent_root = root->fs_info->extent_root;
1434         int pending_ret;
1435         int ret;
1436
1437         WARN_ON(num_bytes < root->sectorsize);
1438         if (!root->ref_cows)
1439                 ref_generation = 0;
1440
1441         if (root == extent_root) {
1442                 pin_down_bytes(root, bytenr, num_bytes, 1);
1443                 return 0;
1444         }
1445         ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1446                             ref_generation, owner_objectid, owner_offset,
1447                             pin, pin == 0);
1448         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1449         return ret ? ret : pending_ret;
1450 }
1451
1452 static u64 stripe_align(struct btrfs_root *root, u64 val)
1453 {
1454         u64 mask = ((u64)root->stripesize - 1);
1455         u64 ret = (val + mask) & ~mask;
1456         return ret;
1457 }
1458
1459 /*
1460  * walks the btree of allocated extents and find a hole of a given size.
1461  * The key ins is changed to record the hole:
1462  * ins->objectid == block start
1463  * ins->flags = BTRFS_EXTENT_ITEM_KEY
1464  * ins->offset == number of blocks
1465  * Any available blocks before search_start are skipped.
1466  */
1467 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1468                                      struct btrfs_root *orig_root,
1469                                      u64 num_bytes, u64 empty_size,
1470                                      u64 search_start, u64 search_end,
1471                                      u64 hint_byte, struct btrfs_key *ins,
1472                                      u64 exclude_start, u64 exclude_nr,
1473                                      int data)
1474 {
1475         int ret;
1476         u64 orig_search_start = search_start;
1477         struct btrfs_root * root = orig_root->fs_info->extent_root;
1478         struct btrfs_fs_info *info = root->fs_info;
1479         u64 total_needed = num_bytes;
1480         struct btrfs_block_group_cache *block_group;
1481         int full_scan = 0;
1482         int wrapped = 0;
1483
1484         WARN_ON(num_bytes < root->sectorsize);
1485         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1486
1487         if (search_end == (u64)-1)
1488                 search_end = btrfs_super_total_bytes(&info->super_copy);
1489
1490         if (hint_byte) {
1491                 block_group = btrfs_lookup_block_group(info, hint_byte);
1492                 if (!block_group)
1493                         hint_byte = search_start;
1494                 block_group = btrfs_find_block_group(root, block_group,
1495                                                      hint_byte, data, 1);
1496         } else {
1497                 block_group = btrfs_find_block_group(root,
1498                                                      trans->block_group,
1499                                                      search_start, data, 1);
1500         }
1501
1502         total_needed += empty_size;
1503
1504 check_failed:
1505         if (!block_group) {
1506                 block_group = btrfs_lookup_block_group(info, search_start);
1507                 if (!block_group)
1508                         block_group = btrfs_lookup_block_group(info,
1509                                                        orig_search_start);
1510         }
1511         ret = find_search_start(root, &block_group, &search_start,
1512                                 total_needed, data);
1513         if (ret)
1514                 goto error;
1515
1516         search_start = stripe_align(root, search_start);
1517         ins->objectid = search_start;
1518         ins->offset = num_bytes;
1519
1520         if (ins->objectid + num_bytes >= search_end)
1521                 goto enospc;
1522
1523         if (ins->objectid + num_bytes >
1524             block_group->key.objectid + block_group->key.offset) {
1525                 search_start = block_group->key.objectid +
1526                         block_group->key.offset;
1527                 goto new_group;
1528         }
1529
1530         if (test_range_bit(&info->extent_ins, ins->objectid,
1531                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1532                 search_start = ins->objectid + num_bytes;
1533                 goto new_group;
1534         }
1535
1536         if (test_range_bit(&info->pinned_extents, ins->objectid,
1537                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1538                 search_start = ins->objectid + num_bytes;
1539                 goto new_group;
1540         }
1541
1542         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1543             ins->objectid < exclude_start + exclude_nr)) {
1544                 search_start = exclude_start + exclude_nr;
1545                 goto new_group;
1546         }
1547
1548         if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1549                 block_group = btrfs_lookup_block_group(info, ins->objectid);
1550                 if (block_group)
1551                         trans->block_group = block_group;
1552         }
1553         ins->offset = num_bytes;
1554         return 0;
1555
1556 new_group:
1557         if (search_start + num_bytes >= search_end) {
1558 enospc:
1559                 search_start = orig_search_start;
1560                 if (full_scan) {
1561                         ret = -ENOSPC;
1562                         goto error;
1563                 }
1564                 if (wrapped) {
1565                         if (!full_scan)
1566                                 total_needed -= empty_size;
1567                         full_scan = 1;
1568                 } else
1569                         wrapped = 1;
1570         }
1571         block_group = btrfs_lookup_block_group(info, search_start);
1572         cond_resched();
1573         block_group = btrfs_find_block_group(root, block_group,
1574                                              search_start, data, 0);
1575         goto check_failed;
1576
1577 error:
1578         return ret;
1579 }
1580 /*
1581  * finds a free extent and does all the dirty work required for allocation
1582  * returns the key for the extent through ins, and a tree buffer for
1583  * the first block of the extent through buf.
1584  *
1585  * returns 0 if everything worked, non-zero otherwise.
1586  */
1587 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1588                        struct btrfs_root *root,
1589                        u64 num_bytes, u64 root_objectid, u64 ref_generation,
1590                        u64 owner, u64 owner_offset,
1591                        u64 empty_size, u64 hint_byte,
1592                        u64 search_end, struct btrfs_key *ins, int data)
1593 {
1594         int ret;
1595         int pending_ret;
1596         u64 super_used;
1597         u64 root_used;
1598         u64 search_start = 0;
1599         u64 new_hint;
1600         u32 sizes[2];
1601         struct btrfs_fs_info *info = root->fs_info;
1602         struct btrfs_root *extent_root = info->extent_root;
1603         struct btrfs_extent_item *extent_item;
1604         struct btrfs_extent_ref *ref;
1605         struct btrfs_path *path;
1606         struct btrfs_key keys[2];
1607
1608         if (data) {
1609                 data = BTRFS_BLOCK_GROUP_DATA;
1610         } else if (root == root->fs_info->chunk_root) {
1611                 data = BTRFS_BLOCK_GROUP_SYSTEM;
1612         } else {
1613                 data = BTRFS_BLOCK_GROUP_METADATA;
1614         }
1615
1616         if (root->ref_cows) {
1617                 if (data != BTRFS_BLOCK_GROUP_METADATA) {
1618                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1619                                              num_bytes,
1620                                              BTRFS_BLOCK_GROUP_METADATA);
1621                         BUG_ON(ret);
1622                 }
1623                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1624                                      num_bytes, data);
1625                 BUG_ON(ret);
1626         }
1627
1628         new_hint = max(hint_byte, root->fs_info->alloc_start);
1629         if (new_hint < btrfs_super_total_bytes(&info->super_copy))
1630                 hint_byte = new_hint;
1631
1632         WARN_ON(num_bytes < root->sectorsize);
1633         ret = find_free_extent(trans, root, num_bytes, empty_size,
1634                                search_start, search_end, hint_byte, ins,
1635                                trans->alloc_exclude_start,
1636                                trans->alloc_exclude_nr, data);
1637         BUG_ON(ret);
1638         if (ret)
1639                 return ret;
1640
1641         /* block accounting for super block */
1642         super_used = btrfs_super_bytes_used(&info->super_copy);
1643         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1644
1645         /* block accounting for root item */
1646         root_used = btrfs_root_used(&root->root_item);
1647         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1648
1649         clear_extent_dirty(&root->fs_info->free_space_cache,
1650                            ins->objectid, ins->objectid + ins->offset - 1,
1651                            GFP_NOFS);
1652
1653         if (root == extent_root) {
1654                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1655                                 ins->objectid + ins->offset - 1,
1656                                 EXTENT_LOCKED, GFP_NOFS);
1657                 goto update_block;
1658         }
1659
1660         WARN_ON(trans->alloc_exclude_nr);
1661         trans->alloc_exclude_start = ins->objectid;
1662         trans->alloc_exclude_nr = ins->offset;
1663
1664         memcpy(&keys[0], ins, sizeof(*ins));
1665         keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1666                                          owner, owner_offset);
1667         keys[1].objectid = ins->objectid;
1668         keys[1].type = BTRFS_EXTENT_REF_KEY;
1669         sizes[0] = sizeof(*extent_item);
1670         sizes[1] = sizeof(*ref);
1671
1672         path = btrfs_alloc_path();
1673         BUG_ON(!path);
1674
1675         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1676                                        sizes, 2);
1677
1678         BUG_ON(ret);
1679         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1680                                      struct btrfs_extent_item);
1681         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1682         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1683                              struct btrfs_extent_ref);
1684
1685         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1686         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1687         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1688         btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1689
1690         btrfs_mark_buffer_dirty(path->nodes[0]);
1691
1692         trans->alloc_exclude_start = 0;
1693         trans->alloc_exclude_nr = 0;
1694         btrfs_free_path(path);
1695         finish_current_insert(trans, extent_root);
1696         pending_ret = del_pending_extents(trans, extent_root);
1697
1698         if (ret) {
1699                 return ret;
1700         }
1701         if (pending_ret) {
1702                 return pending_ret;
1703         }
1704
1705 update_block:
1706         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1707         if (ret) {
1708                 printk("update block group failed for %Lu %Lu\n",
1709                        ins->objectid, ins->offset);
1710                 BUG();
1711         }
1712         return 0;
1713 }
1714
1715 /*
1716  * helper function to allocate a block for a given tree
1717  * returns the tree buffer or NULL.
1718  */
1719 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1720                                              struct btrfs_root *root,
1721                                              u32 blocksize,
1722                                              u64 root_objectid, u64 hint,
1723                                              u64 empty_size)
1724 {
1725         u64 ref_generation;
1726
1727         if (root->ref_cows)
1728                 ref_generation = trans->transid;
1729         else
1730                 ref_generation = 0;
1731
1732
1733         return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1734                                         ref_generation, 0, 0, hint, empty_size);
1735 }
1736
1737 /*
1738  * helper function to allocate a block for a given tree
1739  * returns the tree buffer or NULL.
1740  */
1741 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1742                                              struct btrfs_root *root,
1743                                              u32 blocksize,
1744                                              u64 root_objectid,
1745                                              u64 ref_generation,
1746                                              u64 first_objectid,
1747                                              int level,
1748                                              u64 hint,
1749                                              u64 empty_size)
1750 {
1751         struct btrfs_key ins;
1752         int ret;
1753         struct extent_buffer *buf;
1754
1755         ret = btrfs_alloc_extent(trans, root, blocksize,
1756                                  root_objectid, ref_generation,
1757                                  level, first_objectid, empty_size, hint,
1758                                  (u64)-1, &ins, 0);
1759         if (ret) {
1760                 BUG_ON(ret > 0);
1761                 return ERR_PTR(ret);
1762         }
1763         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1764         if (!buf) {
1765                 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1766                                   root->root_key.objectid, ref_generation,
1767                                   0, 0, 0);
1768                 return ERR_PTR(-ENOMEM);
1769         }
1770         btrfs_set_header_generation(buf, trans->transid);
1771         clean_tree_block(trans, root, buf);
1772         wait_on_tree_block_writeback(root, buf);
1773         btrfs_set_buffer_uptodate(buf);
1774
1775         if (PageDirty(buf->first_page)) {
1776                 printk("page %lu dirty\n", buf->first_page->index);
1777                 WARN_ON(1);
1778         }
1779
1780         set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1781                          buf->start + buf->len - 1, GFP_NOFS);
1782         set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->io_tree,
1783                         buf->start, buf->start + buf->len - 1,
1784                         EXTENT_CSUM, GFP_NOFS);
1785         buf->flags |= EXTENT_CSUM;
1786         if (!btrfs_test_opt(root, SSD))
1787                 btrfs_set_buffer_defrag(buf);
1788         trans->blocks_used++;
1789         return buf;
1790 }
1791
1792 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1793                                   struct btrfs_root *root,
1794                                   struct extent_buffer *leaf)
1795 {
1796         u64 leaf_owner;
1797         u64 leaf_generation;
1798         struct btrfs_key key;
1799         struct btrfs_file_extent_item *fi;
1800         int i;
1801         int nritems;
1802         int ret;
1803
1804         BUG_ON(!btrfs_is_leaf(leaf));
1805         nritems = btrfs_header_nritems(leaf);
1806         leaf_owner = btrfs_header_owner(leaf);
1807         leaf_generation = btrfs_header_generation(leaf);
1808
1809         for (i = 0; i < nritems; i++) {
1810                 u64 disk_bytenr;
1811
1812                 btrfs_item_key_to_cpu(leaf, &key, i);
1813                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1814                         continue;
1815                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1816                 if (btrfs_file_extent_type(leaf, fi) ==
1817                     BTRFS_FILE_EXTENT_INLINE)
1818                         continue;
1819                 /*
1820                  * FIXME make sure to insert a trans record that
1821                  * repeats the snapshot del on crash
1822                  */
1823                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1824                 if (disk_bytenr == 0)
1825                         continue;
1826                 ret = btrfs_free_extent(trans, root, disk_bytenr,
1827                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
1828                                 leaf_owner, leaf_generation,
1829                                 key.objectid, key.offset, 0);
1830                 BUG_ON(ret);
1831         }
1832         return 0;
1833 }
1834
1835 static void noinline reada_walk_down(struct btrfs_root *root,
1836                                      struct extent_buffer *node,
1837                                      int slot)
1838 {
1839         u64 bytenr;
1840         u64 last = 0;
1841         u32 nritems;
1842         u32 refs;
1843         u32 blocksize;
1844         int ret;
1845         int i;
1846         int level;
1847         int skipped = 0;
1848
1849         nritems = btrfs_header_nritems(node);
1850         level = btrfs_header_level(node);
1851         if (level)
1852                 return;
1853
1854         for (i = slot; i < nritems && skipped < 32; i++) {
1855                 bytenr = btrfs_node_blockptr(node, i);
1856                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1857                              (last > bytenr && last - bytenr > 32 * 1024))) {
1858                         skipped++;
1859                         continue;
1860                 }
1861                 blocksize = btrfs_level_size(root, level - 1);
1862                 if (i != slot) {
1863                         ret = lookup_extent_ref(NULL, root, bytenr,
1864                                                 blocksize, &refs);
1865                         BUG_ON(ret);
1866                         if (refs != 1) {
1867                                 skipped++;
1868                                 continue;
1869                         }
1870                 }
1871                 mutex_unlock(&root->fs_info->fs_mutex);
1872                 ret = readahead_tree_block(root, bytenr, blocksize);
1873                 last = bytenr + blocksize;
1874                 cond_resched();
1875                 mutex_lock(&root->fs_info->fs_mutex);
1876                 if (ret)
1877                         break;
1878         }
1879 }
1880
1881 /*
1882  * helper function for drop_snapshot, this walks down the tree dropping ref
1883  * counts as it goes.
1884  */
1885 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1886                                    struct btrfs_root *root,
1887                                    struct btrfs_path *path, int *level)
1888 {
1889         u64 root_owner;
1890         u64 root_gen;
1891         u64 bytenr;
1892         struct extent_buffer *next;
1893         struct extent_buffer *cur;
1894         struct extent_buffer *parent;
1895         u32 blocksize;
1896         int ret;
1897         u32 refs;
1898
1899         WARN_ON(*level < 0);
1900         WARN_ON(*level >= BTRFS_MAX_LEVEL);
1901         ret = lookup_extent_ref(trans, root,
1902                                 path->nodes[*level]->start,
1903                                 path->nodes[*level]->len, &refs);
1904         BUG_ON(ret);
1905         if (refs > 1)
1906                 goto out;
1907
1908         /*
1909          * walk down to the last node level and free all the leaves
1910          */
1911         while(*level >= 0) {
1912                 WARN_ON(*level < 0);
1913                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1914                 cur = path->nodes[*level];
1915
1916                 if (btrfs_header_level(cur) != *level)
1917                         WARN_ON(1);
1918
1919                 if (path->slots[*level] >=
1920                     btrfs_header_nritems(cur))
1921                         break;
1922                 if (*level == 0) {
1923                         ret = drop_leaf_ref(trans, root, cur);
1924                         BUG_ON(ret);
1925                         break;
1926                 }
1927                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1928                 blocksize = btrfs_level_size(root, *level - 1);
1929                 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1930                 BUG_ON(ret);
1931                 if (refs != 1) {
1932                         parent = path->nodes[*level];
1933                         root_owner = btrfs_header_owner(parent);
1934                         root_gen = btrfs_header_generation(parent);
1935                         path->slots[*level]++;
1936                         ret = btrfs_free_extent(trans, root, bytenr,
1937                                                 blocksize, root_owner,
1938                                                 root_gen, 0, 0, 1);
1939                         BUG_ON(ret);
1940                         continue;
1941                 }
1942                 next = btrfs_find_tree_block(root, bytenr, blocksize);
1943                 if (!next || !btrfs_buffer_uptodate(next)) {
1944                         free_extent_buffer(next);
1945                         reada_walk_down(root, cur, path->slots[*level]);
1946                         mutex_unlock(&root->fs_info->fs_mutex);
1947                         next = read_tree_block(root, bytenr, blocksize);
1948                         mutex_lock(&root->fs_info->fs_mutex);
1949
1950                         /* we dropped the lock, check one more time */
1951                         ret = lookup_extent_ref(trans, root, bytenr,
1952                                                 blocksize, &refs);
1953                         BUG_ON(ret);
1954                         if (refs != 1) {
1955                                 parent = path->nodes[*level];
1956                                 root_owner = btrfs_header_owner(parent);
1957                                 root_gen = btrfs_header_generation(parent);
1958
1959                                 path->slots[*level]++;
1960                                 free_extent_buffer(next);
1961                                 ret = btrfs_free_extent(trans, root, bytenr,
1962                                                         blocksize,
1963                                                         root_owner,
1964                                                         root_gen, 0, 0, 1);
1965                                 BUG_ON(ret);
1966                                 continue;
1967                         }
1968                 }
1969                 WARN_ON(*level <= 0);
1970                 if (path->nodes[*level-1])
1971                         free_extent_buffer(path->nodes[*level-1]);
1972                 path->nodes[*level-1] = next;
1973                 *level = btrfs_header_level(next);
1974                 path->slots[*level] = 0;
1975         }
1976 out:
1977         WARN_ON(*level < 0);
1978         WARN_ON(*level >= BTRFS_MAX_LEVEL);
1979
1980         if (path->nodes[*level] == root->node) {
1981                 root_owner = root->root_key.objectid;
1982                 parent = path->nodes[*level];
1983         } else {
1984                 parent = path->nodes[*level + 1];
1985                 root_owner = btrfs_header_owner(parent);
1986         }
1987
1988         root_gen = btrfs_header_generation(parent);
1989         ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1990                                 path->nodes[*level]->len,
1991                                 root_owner, root_gen, 0, 0, 1);
1992         free_extent_buffer(path->nodes[*level]);
1993         path->nodes[*level] = NULL;
1994         *level += 1;
1995         BUG_ON(ret);
1996         return 0;
1997 }
1998
1999 /*
2000  * helper for dropping snapshots.  This walks back up the tree in the path
2001  * to find the first node higher up where we haven't yet gone through
2002  * all the slots
2003  */
2004 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2005                                  struct btrfs_root *root,
2006                                  struct btrfs_path *path, int *level)
2007 {
2008         u64 root_owner;
2009         u64 root_gen;
2010         struct btrfs_root_item *root_item = &root->root_item;
2011         int i;
2012         int slot;
2013         int ret;
2014
2015         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2016                 slot = path->slots[i];
2017                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2018                         struct extent_buffer *node;
2019                         struct btrfs_disk_key disk_key;
2020                         node = path->nodes[i];
2021                         path->slots[i]++;
2022                         *level = i;
2023                         WARN_ON(*level == 0);
2024                         btrfs_node_key(node, &disk_key, path->slots[i]);
2025                         memcpy(&root_item->drop_progress,
2026                                &disk_key, sizeof(disk_key));
2027                         root_item->drop_level = i;
2028                         return 0;
2029                 } else {
2030                         if (path->nodes[*level] == root->node) {
2031                                 root_owner = root->root_key.objectid;
2032                                 root_gen =
2033                                    btrfs_header_generation(path->nodes[*level]);
2034                         } else {
2035                                 struct extent_buffer *node;
2036                                 node = path->nodes[*level + 1];
2037                                 root_owner = btrfs_header_owner(node);
2038                                 root_gen = btrfs_header_generation(node);
2039                         }
2040                         ret = btrfs_free_extent(trans, root,
2041                                                 path->nodes[*level]->start,
2042                                                 path->nodes[*level]->len,
2043                                                 root_owner, root_gen, 0, 0, 1);
2044                         BUG_ON(ret);
2045                         free_extent_buffer(path->nodes[*level]);
2046                         path->nodes[*level] = NULL;
2047                         *level = i + 1;
2048                 }
2049         }
2050         return 1;
2051 }
2052
2053 /*
2054  * drop the reference count on the tree rooted at 'snap'.  This traverses
2055  * the tree freeing any blocks that have a ref count of zero after being
2056  * decremented.
2057  */
2058 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2059                         *root)
2060 {
2061         int ret = 0;
2062         int wret;
2063         int level;
2064         struct btrfs_path *path;
2065         int i;
2066         int orig_level;
2067         struct btrfs_root_item *root_item = &root->root_item;
2068
2069         path = btrfs_alloc_path();
2070         BUG_ON(!path);
2071
2072         level = btrfs_header_level(root->node);
2073         orig_level = level;
2074         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2075                 path->nodes[level] = root->node;
2076                 extent_buffer_get(root->node);
2077                 path->slots[level] = 0;
2078         } else {
2079                 struct btrfs_key key;
2080                 struct btrfs_disk_key found_key;
2081                 struct extent_buffer *node;
2082
2083                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2084                 level = root_item->drop_level;
2085                 path->lowest_level = level;
2086                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2087                 if (wret < 0) {
2088                         ret = wret;
2089                         goto out;
2090                 }
2091                 node = path->nodes[level];
2092                 btrfs_node_key(node, &found_key, path->slots[level]);
2093                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2094                                sizeof(found_key)));
2095         }
2096         while(1) {
2097                 wret = walk_down_tree(trans, root, path, &level);
2098                 if (wret > 0)
2099                         break;
2100                 if (wret < 0)
2101                         ret = wret;
2102
2103                 wret = walk_up_tree(trans, root, path, &level);
2104                 if (wret > 0)
2105                         break;
2106                 if (wret < 0)
2107                         ret = wret;
2108                 ret = -EAGAIN;
2109                 break;
2110         }
2111         for (i = 0; i <= orig_level; i++) {
2112                 if (path->nodes[i]) {
2113                         free_extent_buffer(path->nodes[i]);
2114                         path->nodes[i] = NULL;
2115                 }
2116         }
2117 out:
2118         btrfs_free_path(path);
2119         return ret;
2120 }
2121
2122 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2123 {
2124         u64 start;
2125         u64 end;
2126         u64 ptr;
2127         int ret;
2128         while(1) {
2129                 ret = find_first_extent_bit(&info->block_group_cache, 0,
2130                                             &start, &end, (unsigned int)-1);
2131                 if (ret)
2132                         break;
2133                 ret = get_state_private(&info->block_group_cache, start, &ptr);
2134                 if (!ret)
2135                         kfree((void *)(unsigned long)ptr);
2136                 clear_extent_bits(&info->block_group_cache, start,
2137                                   end, (unsigned int)-1, GFP_NOFS);
2138         }
2139         while(1) {
2140                 ret = find_first_extent_bit(&info->free_space_cache, 0,
2141                                             &start, &end, EXTENT_DIRTY);
2142                 if (ret)
2143                         break;
2144                 clear_extent_dirty(&info->free_space_cache, start,
2145                                    end, GFP_NOFS);
2146         }
2147         return 0;
2148 }
2149
2150 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2151                                          u64 len)
2152 {
2153         u64 page_start;
2154         u64 page_end;
2155         u64 delalloc_start;
2156         u64 existing_delalloc;
2157         unsigned long last_index;
2158         unsigned long i;
2159         struct page *page;
2160         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2161         struct file_ra_state *ra;
2162
2163         ra = kzalloc(sizeof(*ra), GFP_NOFS);
2164
2165         mutex_lock(&inode->i_mutex);
2166         i = start >> PAGE_CACHE_SHIFT;
2167         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2168
2169         file_ra_state_init(ra, inode->i_mapping);
2170         btrfs_force_ra(inode->i_mapping, ra, NULL, i, last_index);
2171         kfree(ra);
2172
2173         for (; i <= last_index; i++) {
2174                 page = grab_cache_page(inode->i_mapping, i);
2175                 if (!page)
2176                         goto out_unlock;
2177                 if (!PageUptodate(page)) {
2178                         btrfs_readpage(NULL, page);
2179                         lock_page(page);
2180                         if (!PageUptodate(page)) {
2181                                 unlock_page(page);
2182                                 page_cache_release(page);
2183                                 goto out_unlock;
2184                         }
2185                 }
2186                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2187                 page_end = page_start + PAGE_CACHE_SIZE - 1;
2188
2189                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2190
2191                 delalloc_start = page_start;
2192                 existing_delalloc = count_range_bits(io_tree,
2193                                              &delalloc_start, page_end,
2194                                              PAGE_CACHE_SIZE, EXTENT_DELALLOC);
2195
2196                 set_extent_delalloc(io_tree, page_start,
2197                                     page_end, GFP_NOFS);
2198
2199                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2200                 set_page_dirty(page);
2201                 unlock_page(page);
2202                 page_cache_release(page);
2203         }
2204
2205 out_unlock:
2206         mutex_unlock(&inode->i_mutex);
2207         return 0;
2208 }
2209
2210 /*
2211  * note, this releases the path
2212  */
2213 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2214                                   struct btrfs_path *path,
2215                                   struct btrfs_key *extent_key)
2216 {
2217         struct inode *inode;
2218         struct btrfs_root *found_root;
2219         struct btrfs_key *root_location;
2220         struct btrfs_extent_ref *ref;
2221         u64 ref_root;
2222         u64 ref_gen;
2223         u64 ref_objectid;
2224         u64 ref_offset;
2225         int ret;
2226
2227         ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2228                              struct btrfs_extent_ref);
2229         ref_root = btrfs_ref_root(path->nodes[0], ref);
2230         ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2231         ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2232         ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2233         btrfs_release_path(extent_root, path);
2234
2235         root_location = kmalloc(sizeof(*root_location), GFP_NOFS);
2236         root_location->objectid = ref_root;
2237         if (ref_gen == 0)
2238                 root_location->offset = 0;
2239         else
2240                 root_location->offset = (u64)-1;
2241         root_location->type = BTRFS_ROOT_ITEM_KEY;
2242
2243         found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2244                                                 root_location);
2245         BUG_ON(!found_root);
2246         kfree(root_location);
2247
2248         if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2249                 mutex_unlock(&extent_root->fs_info->fs_mutex);
2250                 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2251                                           ref_objectid, found_root);
2252                 if (inode->i_state & I_NEW) {
2253                         /* the inode and parent dir are two different roots */
2254                         BTRFS_I(inode)->root = found_root;
2255                         BTRFS_I(inode)->location.objectid = ref_objectid;
2256                         BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2257                         BTRFS_I(inode)->location.offset = 0;
2258                         btrfs_read_locked_inode(inode);
2259                         unlock_new_inode(inode);
2260
2261                 }
2262                 /* this can happen if the reference is not against
2263                  * the latest version of the tree root
2264                  */
2265                 if (is_bad_inode(inode)) {
2266                         mutex_lock(&extent_root->fs_info->fs_mutex);
2267                         goto out;
2268                 }
2269                 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2270                 /* FIXME, data=ordered will help get rid of this */
2271                 filemap_fdatawrite(inode->i_mapping);
2272                 iput(inode);
2273                 mutex_lock(&extent_root->fs_info->fs_mutex);
2274         } else {
2275                 struct btrfs_trans_handle *trans;
2276                 struct btrfs_key found_key;
2277                 struct extent_buffer *eb;
2278                 int level;
2279                 int i;
2280
2281                 trans = btrfs_start_transaction(found_root, 1);
2282                 eb = read_tree_block(found_root, extent_key->objectid,
2283                                      extent_key->offset);
2284                 level = btrfs_header_level(eb);
2285
2286                 if (level == 0)
2287                         btrfs_item_key_to_cpu(eb, &found_key, 0);
2288                 else
2289                         btrfs_node_key_to_cpu(eb, &found_key, 0);
2290
2291                 free_extent_buffer(eb);
2292
2293                 path->lowest_level = level;
2294                 path->reada = 2;
2295                 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2296                                         0, 1);
2297                 path->lowest_level = 0;
2298                 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2299                         if (!path->nodes[i])
2300                                 break;
2301                         free_extent_buffer(path->nodes[i]);
2302                         path->nodes[i] = NULL;
2303                 }
2304                 btrfs_release_path(found_root, path);
2305                 btrfs_end_transaction(trans, found_root);
2306         }
2307
2308 out:
2309         return 0;
2310 }
2311
2312 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2313                                         struct btrfs_path *path,
2314                                         struct btrfs_key *extent_key)
2315 {
2316         struct btrfs_key key;
2317         struct btrfs_key found_key;
2318         struct extent_buffer *leaf;
2319         u32 nritems;
2320         u32 item_size;
2321         int ret = 0;
2322
2323         key.objectid = extent_key->objectid;
2324         key.type = BTRFS_EXTENT_REF_KEY;
2325         key.offset = 0;
2326
2327         while(1) {
2328                 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2329
2330                 if (ret < 0)
2331                         goto out;
2332
2333                 ret = 0;
2334                 leaf = path->nodes[0];
2335                 nritems = btrfs_header_nritems(leaf);
2336                 if (path->slots[0] == nritems)
2337                         goto out;
2338
2339                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2340                 if (found_key.objectid != extent_key->objectid)
2341                         break;
2342
2343                 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2344                         break;
2345
2346                 key.offset = found_key.offset + 1;
2347                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2348
2349                 ret = relocate_one_reference(extent_root, path, extent_key);
2350                 if (ret)
2351                         goto out;
2352         }
2353         ret = 0;
2354 out:
2355         btrfs_release_path(extent_root, path);
2356         return ret;
2357 }
2358
2359 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
2360 {
2361         struct btrfs_trans_handle *trans;
2362         struct btrfs_root *tree_root = root->fs_info->tree_root;
2363         struct btrfs_path *path;
2364         u64 cur_byte;
2365         u64 total_found;
2366         struct btrfs_fs_info *info = root->fs_info;
2367         struct extent_io_tree *block_group_cache;
2368         struct btrfs_key key;
2369         struct btrfs_key found_key;
2370         struct extent_buffer *leaf;
2371         u32 nritems;
2372         int ret;
2373         int progress = 0;
2374
2375         btrfs_set_super_total_bytes(&info->super_copy, new_size);
2376         clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2377                            GFP_NOFS);
2378         block_group_cache = &info->block_group_cache;
2379         path = btrfs_alloc_path();
2380         root = root->fs_info->extent_root;
2381         path->reada = 2;
2382
2383 again:
2384         total_found = 0;
2385         key.objectid = new_size;
2386         key.offset = 0;
2387         key.type = 0;
2388         cur_byte = key.objectid;
2389
2390         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2391         if (ret < 0)
2392                 goto out;
2393
2394         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
2395         if (ret < 0)
2396                 goto out;
2397         if (ret == 0) {
2398                 leaf = path->nodes[0];
2399                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2400                 if (found_key.objectid + found_key.offset > new_size) {
2401                         cur_byte = found_key.objectid;
2402                         key.objectid = cur_byte;
2403                 }
2404         }
2405         btrfs_release_path(root, path);
2406
2407         while(1) {
2408                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2409                 if (ret < 0)
2410                         goto out;
2411
2412                 leaf = path->nodes[0];
2413                 nritems = btrfs_header_nritems(leaf);
2414 next:
2415                 if (path->slots[0] >= nritems) {
2416                         ret = btrfs_next_leaf(root, path);
2417                         if (ret < 0)
2418                                 goto out;
2419                         if (ret == 1) {
2420                                 ret = 0;
2421                                 break;
2422                         }
2423                         leaf = path->nodes[0];
2424                         nritems = btrfs_header_nritems(leaf);
2425                 }
2426
2427                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2428
2429                 if (progress && need_resched()) {
2430                         memcpy(&key, &found_key, sizeof(key));
2431                         mutex_unlock(&root->fs_info->fs_mutex);
2432                         cond_resched();
2433                         mutex_lock(&root->fs_info->fs_mutex);
2434                         btrfs_release_path(root, path);
2435                         btrfs_search_slot(NULL, root, &key, path, 0, 0);
2436                         progress = 0;
2437                         goto next;
2438                 }
2439                 progress = 1;
2440
2441                 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
2442                     found_key.objectid + found_key.offset <= cur_byte) {
2443                         path->slots[0]++;
2444                         goto next;
2445                 }
2446
2447                 total_found++;
2448                 cur_byte = found_key.objectid + found_key.offset;
2449                 key.objectid = cur_byte;
2450                 btrfs_release_path(root, path);
2451                 ret = relocate_one_extent(root, path, &found_key);
2452         }
2453
2454         btrfs_release_path(root, path);
2455
2456         if (total_found > 0) {
2457                 trans = btrfs_start_transaction(tree_root, 1);
2458                 btrfs_commit_transaction(trans, tree_root);
2459
2460                 mutex_unlock(&root->fs_info->fs_mutex);
2461                 btrfs_clean_old_snapshots(tree_root);
2462                 mutex_lock(&root->fs_info->fs_mutex);
2463
2464                 trans = btrfs_start_transaction(tree_root, 1);
2465                 btrfs_commit_transaction(trans, tree_root);
2466                 goto again;
2467         }
2468
2469         trans = btrfs_start_transaction(root, 1);
2470         key.objectid = new_size;
2471         key.offset = 0;
2472         key.type = 0;
2473         while(1) {
2474                 u64 ptr;
2475
2476                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2477                 if (ret < 0)
2478                         goto out;
2479
2480                 leaf = path->nodes[0];
2481                 nritems = btrfs_header_nritems(leaf);
2482 bg_next:
2483                 if (path->slots[0] >= nritems) {
2484                         ret = btrfs_next_leaf(root, path);
2485                         if (ret < 0)
2486                                 break;
2487                         if (ret == 1) {
2488                                 ret = 0;
2489                                 break;
2490                         }
2491                         leaf = path->nodes[0];
2492                         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2493
2494                         /*
2495                          * btrfs_next_leaf doesn't cow buffers, we have to
2496                          * do the search again
2497                          */
2498                         memcpy(&key, &found_key, sizeof(key));
2499                         btrfs_release_path(root, path);
2500                         goto resched_check;
2501                 }
2502
2503                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2504                 if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
2505                         printk("shrinker found key %Lu %u %Lu\n",
2506                                 found_key.objectid, found_key.type,
2507                                 found_key.offset);
2508                         path->slots[0]++;
2509                         goto bg_next;
2510                 }
2511                 ret = get_state_private(&info->block_group_cache,
2512                                         found_key.objectid, &ptr);
2513                 if (!ret)
2514                         kfree((void *)(unsigned long)ptr);
2515
2516                 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2517                                   found_key.objectid + found_key.offset - 1,
2518                                   (unsigned int)-1, GFP_NOFS);
2519
2520                 key.objectid = found_key.objectid + 1;
2521                 btrfs_del_item(trans, root, path);
2522                 btrfs_release_path(root, path);
2523 resched_check:
2524                 if (need_resched()) {
2525                         mutex_unlock(&root->fs_info->fs_mutex);
2526                         cond_resched();
2527                         mutex_lock(&root->fs_info->fs_mutex);
2528                 }
2529         }
2530         clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2531                            GFP_NOFS);
2532         btrfs_commit_transaction(trans, root);
2533 out:
2534         btrfs_free_path(path);
2535         return ret;
2536 }
2537
2538 int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
2539                            struct btrfs_root *root, u64 new_size)
2540 {
2541         btrfs_set_super_total_bytes(&root->fs_info->super_copy, new_size);
2542         return 0;
2543 }
2544
2545 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2546                            struct btrfs_key *key)
2547 {
2548         int ret;
2549         struct btrfs_key found_key;
2550         struct extent_buffer *leaf;
2551         int slot;
2552
2553         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2554         if (ret < 0)
2555                 return ret;
2556         while(1) {
2557                 slot = path->slots[0];
2558                 leaf = path->nodes[0];
2559                 if (slot >= btrfs_header_nritems(leaf)) {
2560                         ret = btrfs_next_leaf(root, path);
2561                         if (ret == 0)
2562                                 continue;
2563                         if (ret < 0)
2564                                 goto error;
2565                         break;
2566                 }
2567                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2568
2569                 if (found_key.objectid >= key->objectid &&
2570                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2571                         return 0;
2572                 path->slots[0]++;
2573         }
2574         ret = -ENOENT;
2575 error:
2576         return ret;
2577 }
2578
2579 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2580                              u64 total_bytes, u64 bytes_used,
2581                              struct btrfs_space_info **space_info)
2582 {
2583         struct btrfs_space_info *found;
2584
2585         found = __find_space_info(info, flags);
2586         if (found) {
2587                 found->total_bytes += total_bytes;
2588                 found->bytes_used += bytes_used;
2589                 WARN_ON(found->total_bytes < found->bytes_used);
2590                 *space_info = found;
2591                 return 0;
2592         }
2593         found = kmalloc(sizeof(*found), GFP_NOFS);
2594         if (!found)
2595                 return -ENOMEM;
2596
2597         list_add(&found->list, &info->space_info);
2598         found->flags = flags;
2599         found->total_bytes = total_bytes;
2600         found->bytes_used = bytes_used;
2601         found->bytes_pinned = 0;
2602         found->full = 0;
2603         *space_info = found;
2604         return 0;
2605 }
2606
2607 int btrfs_read_block_groups(struct btrfs_root *root)
2608 {
2609         struct btrfs_path *path;
2610         int ret;
2611         int bit;
2612         struct btrfs_block_group_cache *cache;
2613         struct btrfs_fs_info *info = root->fs_info;
2614         struct btrfs_space_info *space_info;
2615         struct extent_io_tree *block_group_cache;
2616         struct btrfs_key key;
2617         struct btrfs_key found_key;
2618         struct extent_buffer *leaf;
2619
2620         block_group_cache = &info->block_group_cache;
2621         root = info->extent_root;
2622         key.objectid = 0;
2623         key.offset = 0;
2624         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2625         path = btrfs_alloc_path();
2626         if (!path)
2627                 return -ENOMEM;
2628
2629         while(1) {
2630                 ret = find_first_block_group(root, path, &key);
2631                 if (ret > 0) {
2632                         ret = 0;
2633                         goto error;
2634                 }
2635                 if (ret != 0)
2636                         goto error;
2637
2638                 leaf = path->nodes[0];
2639                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2640                 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2641                 if (!cache) {
2642                         ret = -ENOMEM;
2643                         break;
2644                 }
2645
2646                 read_extent_buffer(leaf, &cache->item,
2647                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
2648                                    sizeof(cache->item));
2649                 memcpy(&cache->key, &found_key, sizeof(found_key));
2650                 cache->cached = 0;
2651                 cache->pinned = 0;
2652
2653                 key.objectid = found_key.objectid + found_key.offset;
2654                 btrfs_release_path(root, path);
2655                 cache->flags = btrfs_block_group_flags(&cache->item);
2656                 bit = 0;
2657                 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2658                         bit = BLOCK_GROUP_DATA;
2659                 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2660                         bit = BLOCK_GROUP_SYSTEM;
2661                 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2662                         bit = BLOCK_GROUP_METADATA;
2663                 }
2664
2665                 ret = update_space_info(info, cache->flags, found_key.offset,
2666                                         btrfs_block_group_used(&cache->item),
2667                                         &space_info);
2668                 BUG_ON(ret);
2669                 cache->space_info = space_info;
2670
2671                 /* use EXTENT_LOCKED to prevent merging */
2672                 set_extent_bits(block_group_cache, found_key.objectid,
2673                                 found_key.objectid + found_key.offset - 1,
2674                                 bit | EXTENT_LOCKED, GFP_NOFS);
2675                 set_state_private(block_group_cache, found_key.objectid,
2676                                   (unsigned long)cache);
2677
2678                 if (key.objectid >=
2679                     btrfs_super_total_bytes(&info->super_copy))
2680                         break;
2681         }
2682         ret = 0;
2683 error:
2684         btrfs_free_path(path);
2685         return ret;
2686 }
2687
2688 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2689                            struct btrfs_root *root, u64 bytes_used,
2690                            u64 type, u64 chunk_tree, u64 chunk_objectid,
2691                            u64 size)
2692 {
2693         int ret;
2694         int bit = 0;
2695         struct btrfs_root *extent_root;
2696         struct btrfs_block_group_cache *cache;
2697         struct extent_io_tree *block_group_cache;
2698
2699         extent_root = root->fs_info->extent_root;
2700         block_group_cache = &root->fs_info->block_group_cache;
2701
2702         cache = kmalloc(sizeof(*cache), GFP_NOFS);
2703         BUG_ON(!cache);
2704         cache->key.objectid = chunk_objectid;
2705         cache->key.offset = size;
2706         cache->cached = 0;
2707         cache->pinned = 0;
2708         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2709         memset(&cache->item, 0, sizeof(cache->item));
2710         btrfs_set_block_group_used(&cache->item, bytes_used);
2711         btrfs_set_block_group_chunk_tree(&cache->item, chunk_tree);
2712         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2713         cache->flags = type;
2714         btrfs_set_block_group_flags(&cache->item, type);
2715
2716         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2717                                 &cache->space_info);
2718         BUG_ON(ret);
2719
2720         if (type & BTRFS_BLOCK_GROUP_DATA) {
2721                 bit = BLOCK_GROUP_DATA;
2722         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2723                 bit = BLOCK_GROUP_SYSTEM;
2724         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2725                 bit = BLOCK_GROUP_METADATA;
2726         }
2727         set_extent_bits(block_group_cache, chunk_objectid,
2728                         chunk_objectid + size - 1,
2729                         bit | EXTENT_LOCKED, GFP_NOFS);
2730         set_state_private(block_group_cache, chunk_objectid,
2731                           (unsigned long)cache);
2732
2733         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2734                                 sizeof(cache->item));
2735         BUG_ON(ret);
2736
2737         finish_current_insert(trans, extent_root);
2738         ret = del_pending_extents(trans, extent_root);
2739         BUG_ON(ret);
2740         return 0;
2741 }