SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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
  28 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
  29 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
  30 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
  31
  32 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  33                                  btrfs_root *extent_root);
  34 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  35                                btrfs_root *extent_root);
  36 static int find_previous_extent(struct btrfs_root *root,
  37                                 struct btrfs_path *path)
  38 {
  39         struct btrfs_key found_key;
  40         struct extent_buffer *leaf;
  41         int ret;
  42
  43         while(1) {
  44                 if (path->slots[0] == 0) {
  45                         ret = btrfs_prev_leaf(root, path);
  46                         if (ret != 0)
  47                                 return ret;
  48                 } else {
  49                         path->slots[0]--;
  50                 }
  51                 leaf = path->nodes[0];
  52                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
  53                 if (found_key.type == BTRFS_EXTENT_ITEM_KEY)
  54                         return 0;
  55         }
  56         return 1;
  57 }
  58
  59 static int cache_block_group(struct btrfs_root *root,
  60                              struct btrfs_block_group_cache *block_group)
  61 {
  62         struct btrfs_path *path;
  63         int ret;
  64         struct btrfs_key key;
  65         struct extent_buffer *leaf;
  66         struct extent_io_tree *free_space_cache;
  67         int slot;
  68         u64 last = 0;
  69         u64 hole_size;
  70         u64 first_free;
  71         int found = 0;
  72
  73         if (!block_group)
  74                 return 0;
  75
  76         root = root->fs_info->extent_root;
  77         free_space_cache = &root->fs_info->free_space_cache;
  78
  79         if (block_group->cached)
  80                 return 0;
  81
  82         path = btrfs_alloc_path();
  83         if (!path)
  84                 return -ENOMEM;
  85
  86         path->reada = 2;
  87         first_free = block_group->key.objectid;
  88         key.objectid = block_group->key.objectid;
  89         key.offset = 0;
  90         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
  91         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  92         if (ret < 0)
  93                 return ret;
  94         ret = find_previous_extent(root, path);
  95         if (ret < 0)
  96                 return ret;
  97         if (ret == 0) {
  98                 leaf = path->nodes[0];
  99                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 100                 if (key.objectid + key.offset > first_free)
 101                         first_free = key.objectid + key.offset;
 102         }
 103         while(1) {
 104                 leaf = path->nodes[0];
 105                 slot = path->slots[0];
 106                 if (slot >= btrfs_header_nritems(leaf)) {
 107                         ret = btrfs_next_leaf(root, path);
 108                         if (ret < 0)
 109                                 goto err;
 110                         if (ret == 0) {
 111                                 continue;
 112                         } else {
 113                                 break;
 114                         }
 115                 }
 116                 btrfs_item_key_to_cpu(leaf, &key, slot);
 117                 if (key.objectid < block_group->key.objectid) {
 118                         goto next;
 119                 }
 120                 if (key.objectid >= block_group->key.objectid +
 121                     block_group->key.offset) {
 122                         break;
 123                 }
 124
 125                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 126                         if (!found) {
 127                                 last = first_free;
 128                                 found = 1;
 129                         }
 130                         if (key.objectid > last) {
 131                                 hole_size = key.objectid - last;
 132                                 set_extent_dirty(free_space_cache, last,
 133                                                  last + hole_size - 1,
 134                                                  GFP_NOFS);
 135                         }
 136                         last = key.objectid + key.offset;
 137                 }
 138 next:
 139                 path->slots[0]++;
 140         }
 141
 142         if (!found)
 143                 last = first_free;
 144         if (block_group->key.objectid +
 145             block_group->key.offset > last) {
 146                 hole_size = block_group->key.objectid +
 147                         block_group->key.offset - last;
 148                 set_extent_dirty(free_space_cache, last,
 149                                  last + hole_size - 1, GFP_NOFS);
 150         }
 151         block_group->cached = 1;
 152 err:
 153         btrfs_free_path(path);
 154         return 0;
 155 }
 156
 157 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 158                                                          btrfs_fs_info *info,
 159                                                          u64 bytenr)
 160 {
 161         struct extent_io_tree *block_group_cache;
 162         struct btrfs_block_group_cache *block_group = NULL;
 163         u64 ptr;
 164         u64 start;
 165         u64 end;
 166         int ret;
 167
 168         block_group_cache = &info->block_group_cache;
 169         ret = find_first_extent_bit(block_group_cache,
 170                                     bytenr, &start, &end,
 171                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
 172         if (ret) {
 173                 return NULL;
 174         }
 175         ret = get_state_private(block_group_cache, start, &ptr);
 176         if (ret)
 177                 return NULL;
 178
 179         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 180         if (block_group->key.objectid <= bytenr && bytenr <
 181             block_group->key.objectid + block_group->key.offset)
 182                 return block_group;
 183         return NULL;
 184 }
 185 static u64 noinline find_search_start(struct btrfs_root *root,
 186                               struct btrfs_block_group_cache **cache_ret,
 187                               u64 search_start, int num, int data)
 188 {
 189         int ret;
 190         struct btrfs_block_group_cache *cache = *cache_ret;
 191         struct extent_io_tree *free_space_cache;
 192         struct extent_state *state;
 193         u64 last;
 194         u64 start = 0;
 195         u64 cache_miss = 0;
 196         u64 total_fs_bytes;
 197         int wrapped = 0;
 198
 199         if (!cache) {
 200                 goto out;
 201         }
 202         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 203         free_space_cache = &root->fs_info->free_space_cache;
 204
 205 again:
 206         ret = cache_block_group(root, cache);
 207         if (ret)
 208                 goto out;
 209
 210         last = max(search_start, cache->key.objectid);
 211
 212         while(1) {
 213                 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
 214                                             last, &start, &end, EXTENT_DIRTY);
 215                 if (ret) {
 216                         if (!cache_miss)
 217                                 cache_miss = last;
 218                         goto new_group;
 219                 }
 220
 221                 start = max(last, start);
 222                 last = end + 1;
 223                 if (last - start < num) {
 224                         if (last == cache->key.objectid + cache->key.offset)
 225                                 cache_miss = start;
 226                         continue;
 227                 }
 228                 if (data != BTRFS_BLOCK_GROUP_MIXED &&
 229                     start + num > cache->key.objectid + cache->key.offset)
 230                         goto new_group;
 231                 if (start + num  > total_fs_bytes)
 232                         goto new_group;
 233                 return start;
 234         }
 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",
 239                        search_start);
 240                 WARN_ON(1);
 241                 return search_start;
 242         }
 243         return search_start;
 244
 245 new_group:
 246         last = cache->key.objectid + cache->key.offset;
 247 wrapped:
 248         cache = btrfs_lookup_block_group(root->fs_info, last);
 249         if (!cache || cache->key.objectid >= total_fs_bytes) {
 250 no_cache:
 251                 if (!wrapped) {
 252                         wrapped = 1;
 253                         last = search_start;
 254                         data = BTRFS_BLOCK_GROUP_MIXED;
 255                         goto wrapped;
 256                 }
 257                 goto out;
 258         }
 259         if (cache_miss && !cache->cached) {
 260                 cache_block_group(root, cache);
 261                 last = cache_miss;
 262                 cache = btrfs_lookup_block_group(root->fs_info, last);
 263         }
 264         cache = btrfs_find_block_group(root, cache, last, data, 0);
 265         if (!cache)
 266                 goto no_cache;
 267         *cache_ret = cache;
 268         cache_miss = 0;
 269         goto again;
 270 }
 271
 272 static u64 div_factor(u64 num, int factor)
 273 {
 274         if (factor == 10)
 275                 return num;
 276         num *= factor;
 277         do_div(num, 10);
 278         return num;
 279 }
 280
 281 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 282                                                  struct btrfs_block_group_cache
 283                                                  *hint, u64 search_start,
 284                                                  int data, int owner)
 285 {
 286         struct btrfs_block_group_cache *cache;
 287         struct extent_io_tree *block_group_cache;
 288         struct btrfs_block_group_cache *found_group = NULL;
 289         struct btrfs_fs_info *info = root->fs_info;
 290         u64 used;
 291         u64 last = 0;
 292         u64 hint_last;
 293         u64 start;
 294         u64 end;
 295         u64 free_check;
 296         u64 ptr;
 297         u64 total_fs_bytes;
 298         int bit;
 299         int ret;
 300         int full_search = 0;
 301         int factor = 8;
 302         int data_swap = 0;
 303
 304         block_group_cache = &info->block_group_cache;
 305         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 306
 307         if (!owner)
 308                 factor = 8;
 309
 310         if (data == BTRFS_BLOCK_GROUP_MIXED) {
 311                 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
 312                 factor = 10;
 313         } else if (data)
 314                 bit = BLOCK_GROUP_DATA;
 315         else
 316                 bit = BLOCK_GROUP_METADATA;
 317
 318         if (search_start && search_start < total_fs_bytes) {
 319                 struct btrfs_block_group_cache *shint;
 320                 shint = btrfs_lookup_block_group(info, search_start);
 321                 if (shint && (shint->data == data ||
 322                               shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
 323                         used = btrfs_block_group_used(&shint->item);
 324                         if (used + shint->pinned <
 325                             div_factor(shint->key.offset, factor)) {
 326                                 return shint;
 327                         }
 328                 }
 329         }
 330         if (hint && hint->key.objectid < total_fs_bytes &&
 331             (hint->data == data || hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
 332                 used = btrfs_block_group_used(&hint->item);
 333                 if (used + hint->pinned <
 334                     div_factor(hint->key.offset, factor)) {
 335                         return hint;
 336                 }
 337                 last = hint->key.objectid + hint->key.offset;
 338                 hint_last = last;
 339         } else {
 340                 if (hint)
 341                         hint_last = max(hint->key.objectid, search_start);
 342                 else
 343                         hint_last = search_start;
 344
 345                 if (hint_last >= total_fs_bytes)
 346                         hint_last = search_start;
 347                 last = hint_last;
 348         }
 349 again:
 350         while(1) {
 351                 ret = find_first_extent_bit(block_group_cache, last,
 352                                             &start, &end, bit);
 353                 if (ret)
 354                         break;
 355
 356                 ret = get_state_private(block_group_cache, start, &ptr);
 357                 if (ret)
 358                         break;
 359
 360                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 361                 last = cache->key.objectid + cache->key.offset;
 362                 used = btrfs_block_group_used(&cache->item);
 363
 364                 if (cache->key.objectid > total_fs_bytes)
 365                         break;
 366
 367                 if (full_search)
 368                         free_check = cache->key.offset;
 369                 else
 370                         free_check = div_factor(cache->key.offset, factor);
 371                 if (used + cache->pinned < free_check) {
 372                         found_group = cache;
 373                         goto found;
 374                 }
 375                 cond_resched();
 376         }
 377         if (!full_search) {
 378                 last = search_start;
 379                 full_search = 1;
 380                 goto again;
 381         }
 382         if (!data_swap) {
 383                 data_swap = 1;
 384                 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
 385                 last = search_start;
 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 int update_block_group(struct btrfs_trans_handle *trans,
1003                               struct btrfs_root *root,
1004                               u64 bytenr, u64 num_bytes, int alloc,
1005                               int mark_free, int data)
1006 {
1007         struct btrfs_block_group_cache *cache;
1008         struct btrfs_fs_info *info = root->fs_info;
1009         u64 total = num_bytes;
1010         u64 old_val;
1011         u64 byte_in_group;
1012         u64 start;
1013         u64 end;
1014
1015         while(total) {
1016                 cache = btrfs_lookup_block_group(info, bytenr);
1017                 if (!cache) {
1018                         return -1;
1019                 }
1020                 byte_in_group = bytenr - cache->key.objectid;
1021                 WARN_ON(byte_in_group > cache->key.offset);
1022                 start = cache->key.objectid;
1023                 end = start + cache->key.offset - 1;
1024                 set_extent_bits(&info->block_group_cache, start, end,
1025                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1026
1027                 old_val = btrfs_block_group_used(&cache->item);
1028                 num_bytes = min(total, cache->key.offset - byte_in_group);
1029                 if (alloc) {
1030                         if (cache->data != data &&
1031                             old_val < (cache->key.offset >> 1)) {
1032                                 int bit_to_clear;
1033                                 int bit_to_set;
1034                                 cache->data = data;
1035                                 if (data) {
1036                                         bit_to_clear = BLOCK_GROUP_METADATA;
1037                                         bit_to_set = BLOCK_GROUP_DATA;
1038                                         cache->item.flags &=
1039                                                 ~BTRFS_BLOCK_GROUP_MIXED;
1040                                         cache->item.flags |=
1041                                                 BTRFS_BLOCK_GROUP_DATA;
1042                                 } else {
1043                                         bit_to_clear = BLOCK_GROUP_DATA;
1044                                         bit_to_set = BLOCK_GROUP_METADATA;
1045                                         cache->item.flags &=
1046                                                 ~BTRFS_BLOCK_GROUP_MIXED;
1047                                         cache->item.flags &=
1048                                                 ~BTRFS_BLOCK_GROUP_DATA;
1049                                 }
1050                                 clear_extent_bits(&info->block_group_cache,
1051                                                   start, end, bit_to_clear,
1052                                                   GFP_NOFS);
1053                                 set_extent_bits(&info->block_group_cache,
1054                                                 start, end, bit_to_set,
1055                                                 GFP_NOFS);
1056                         } else if (cache->data != data &&
1057                                    cache->data != BTRFS_BLOCK_GROUP_MIXED) {
1058                                 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1059                                 set_extent_bits(&info->block_group_cache,
1060                                                 start, end,
1061                                                 BLOCK_GROUP_DATA |
1062                                                 BLOCK_GROUP_METADATA,
1063                                                 GFP_NOFS);
1064                         }
1065                         old_val += num_bytes;
1066                 } else {
1067                         old_val -= num_bytes;
1068                         if (mark_free) {
1069                                 set_extent_dirty(&info->free_space_cache,
1070                                                  bytenr, bytenr + num_bytes - 1,
1071                                                  GFP_NOFS);
1072                         }
1073                 }
1074                 btrfs_set_block_group_used(&cache->item, old_val);
1075                 total -= num_bytes;
1076                 bytenr += num_bytes;
1077         }
1078         return 0;
1079 }
1080 static int update_pinned_extents(struct btrfs_root *root,
1081                                 u64 bytenr, u64 num, int pin)
1082 {
1083         u64 len;
1084         struct btrfs_block_group_cache *cache;
1085         struct btrfs_fs_info *fs_info = root->fs_info;
1086
1087         if (pin) {
1088                 set_extent_dirty(&fs_info->pinned_extents,
1089                                 bytenr, bytenr + num - 1, GFP_NOFS);
1090         } else {
1091                 clear_extent_dirty(&fs_info->pinned_extents,
1092                                 bytenr, bytenr + num - 1, GFP_NOFS);
1093         }
1094         while (num > 0) {
1095                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1096                 WARN_ON(!cache);
1097                 len = min(num, cache->key.offset -
1098                           (bytenr - cache->key.objectid));
1099                 if (pin) {
1100                         cache->pinned += len;
1101                         fs_info->total_pinned += len;
1102                 } else {
1103                         cache->pinned -= len;
1104                         fs_info->total_pinned -= len;
1105                 }
1106                 bytenr += len;
1107                 num -= len;
1108         }
1109         return 0;
1110 }
1111
1112 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1113 {
1114         u64 last = 0;
1115         u64 start;
1116         u64 end;
1117         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1118         int ret;
1119
1120         while(1) {
1121                 ret = find_first_extent_bit(pinned_extents, last,
1122                                             &start, &end, EXTENT_DIRTY);
1123                 if (ret)
1124                         break;
1125                 set_extent_dirty(copy, start, end, GFP_NOFS);
1126                 last = end + 1;
1127         }
1128         return 0;
1129 }
1130
1131 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1132                                struct btrfs_root *root,
1133                                struct extent_io_tree *unpin)
1134 {
1135         u64 start;
1136         u64 end;
1137         int ret;
1138         struct extent_io_tree *free_space_cache;
1139         free_space_cache = &root->fs_info->free_space_cache;
1140
1141         while(1) {
1142                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1143                                             EXTENT_DIRTY);
1144                 if (ret)
1145                         break;
1146                 update_pinned_extents(root, start, end + 1 - start, 0);
1147                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1148                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1149         }
1150         return 0;
1151 }
1152
1153 static int finish_current_insert(struct btrfs_trans_handle *trans,
1154                                  struct btrfs_root *extent_root)
1155 {
1156         u64 start;
1157         u64 end;
1158         struct btrfs_fs_info *info = extent_root->fs_info;
1159         struct extent_buffer *eb;
1160         struct btrfs_path *path;
1161         struct btrfs_key ins;
1162         struct btrfs_disk_key first;
1163         struct btrfs_extent_item extent_item;
1164         int ret;
1165         int level;
1166         int err = 0;
1167
1168         btrfs_set_stack_extent_refs(&extent_item, 1);
1169         btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1170         path = btrfs_alloc_path();
1171
1172         while(1) {
1173                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1174                                             &end, EXTENT_LOCKED);
1175                 if (ret)
1176                         break;
1177
1178                 ins.objectid = start;
1179                 ins.offset = end + 1 - start;
1180                 err = btrfs_insert_item(trans, extent_root, &ins,
1181                                         &extent_item, sizeof(extent_item));
1182                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1183                                   GFP_NOFS);
1184                 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1185                 level = btrfs_header_level(eb);
1186                 if (level == 0) {
1187                         btrfs_item_key(eb, &first, 0);
1188                 } else {
1189                         btrfs_node_key(eb, &first, 0);
1190                 }
1191                 err = btrfs_insert_extent_backref(trans, extent_root, path,
1192                                           start, extent_root->root_key.objectid,
1193                                           0, level,
1194                                           btrfs_disk_key_objectid(&first));
1195                 BUG_ON(err);
1196                 free_extent_buffer(eb);
1197         }
1198         btrfs_free_path(path);
1199         return 0;
1200 }
1201
1202 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1203                           int pending)
1204 {
1205         int err = 0;
1206         struct extent_buffer *buf;
1207
1208         if (!pending) {
1209                 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1210                 if (buf) {
1211                         if (btrfs_buffer_uptodate(buf)) {
1212                                 u64 transid =
1213                                     root->fs_info->running_transaction->transid;
1214                                 u64 header_transid =
1215                                         btrfs_header_generation(buf);
1216                                 if (header_transid == transid) {
1217                                         clean_tree_block(NULL, root, buf);
1218                                         free_extent_buffer(buf);
1219                                         return 1;
1220                                 }
1221                         }
1222                         free_extent_buffer(buf);
1223                 }
1224                 update_pinned_extents(root, bytenr, num_bytes, 1);
1225         } else {
1226                 set_extent_bits(&root->fs_info->pending_del,
1227                                 bytenr, bytenr + num_bytes - 1,
1228                                 EXTENT_LOCKED, GFP_NOFS);
1229         }
1230         BUG_ON(err < 0);
1231         return 0;
1232 }
1233
1234 /*
1235  * remove an extent from the root, returns 0 on success
1236  */
1237 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1238                          *root, u64 bytenr, u64 num_bytes,
1239                          u64 root_objectid, u64 ref_generation,
1240                          u64 owner_objectid, u64 owner_offset, int pin,
1241                          int mark_free)
1242 {
1243         struct btrfs_path *path;
1244         struct btrfs_key key;
1245         struct btrfs_fs_info *info = root->fs_info;
1246         struct btrfs_root *extent_root = info->extent_root;
1247         struct extent_buffer *leaf;
1248         int ret;
1249         int extent_slot = 0;
1250         int found_extent = 0;
1251         int num_to_del = 1;
1252         struct btrfs_extent_item *ei;
1253         u32 refs;
1254
1255         key.objectid = bytenr;
1256         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1257         key.offset = num_bytes;
1258         path = btrfs_alloc_path();
1259         if (!path)
1260                 return -ENOMEM;
1261
1262         path->reada = 0;
1263         ret = lookup_extent_backref(trans, extent_root, path,
1264                                     bytenr, root_objectid,
1265                                     ref_generation,
1266                                     owner_objectid, owner_offset, 1);
1267         if (ret == 0) {
1268                 struct btrfs_key found_key;
1269                 extent_slot = path->slots[0];
1270                 while(extent_slot > 0) {
1271                         extent_slot--;
1272                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1273                                               extent_slot);
1274                         if (found_key.objectid != bytenr)
1275                                 break;
1276                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1277                             found_key.offset == num_bytes) {
1278                                 found_extent = 1;
1279                                 break;
1280                         }
1281                         if (path->slots[0] - extent_slot > 5)
1282                                 break;
1283                 }
1284                 if (!found_extent)
1285                         ret = btrfs_del_item(trans, extent_root, path);
1286         } else {
1287                 btrfs_print_leaf(extent_root, path->nodes[0]);
1288                 WARN_ON(1);
1289                 printk("Unable to find ref byte nr %Lu root %Lu "
1290                        " gen %Lu owner %Lu offset %Lu\n", bytenr,
1291                        root_objectid, ref_generation, owner_objectid,
1292                        owner_offset);
1293         }
1294         if (!found_extent) {
1295                 btrfs_release_path(extent_root, path);
1296                 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1297                 if (ret < 0)
1298                         return ret;
1299                 BUG_ON(ret);
1300                 extent_slot = path->slots[0];
1301         }
1302
1303         leaf = path->nodes[0];
1304         ei = btrfs_item_ptr(leaf, extent_slot,
1305                             struct btrfs_extent_item);
1306         refs = btrfs_extent_refs(leaf, ei);
1307         BUG_ON(refs == 0);
1308         refs -= 1;
1309         btrfs_set_extent_refs(leaf, ei, refs);
1310
1311         btrfs_mark_buffer_dirty(leaf);
1312
1313         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1314                 /* if the back ref and the extent are next to each other
1315                  * they get deleted below in one shot
1316                  */
1317                 path->slots[0] = extent_slot;
1318                 num_to_del = 2;
1319         } else if (found_extent) {
1320                 /* otherwise delete the extent back ref */
1321                 ret = btrfs_del_item(trans, extent_root, path);
1322                 BUG_ON(ret);
1323                 /* if refs are 0, we need to setup the path for deletion */
1324                 if (refs == 0) {
1325                         btrfs_release_path(extent_root, path);
1326                         ret = btrfs_search_slot(trans, extent_root, &key, path,
1327                                                 -1, 1);
1328                         if (ret < 0)
1329                                 return ret;
1330                         BUG_ON(ret);
1331                 }
1332         }
1333
1334         if (refs == 0) {
1335                 u64 super_used;
1336                 u64 root_used;
1337
1338                 if (pin) {
1339                         ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1340                         if (ret > 0)
1341                                 mark_free = 1;
1342                         BUG_ON(ret < 0);
1343                 }
1344
1345                 /* block accounting for super block */
1346                 super_used = btrfs_super_bytes_used(&info->super_copy);
1347                 btrfs_set_super_bytes_used(&info->super_copy,
1348                                            super_used - num_bytes);
1349
1350                 /* block accounting for root item */
1351                 root_used = btrfs_root_used(&root->root_item);
1352                 btrfs_set_root_used(&root->root_item,
1353                                            root_used - num_bytes);
1354                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1355                                       num_to_del);
1356                 if (ret) {
1357                         return ret;
1358                 }
1359                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1360                                          mark_free, 0);
1361                 BUG_ON(ret);
1362         }
1363         btrfs_free_path(path);
1364         finish_current_insert(trans, extent_root);
1365         return ret;
1366 }
1367
1368 /*
1369  * find all the blocks marked as pending in the radix tree and remove
1370  * them from the extent map
1371  */
1372 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1373                                btrfs_root *extent_root)
1374 {
1375         int ret;
1376         int err = 0;
1377         u64 start;
1378         u64 end;
1379         struct extent_io_tree *pending_del;
1380         struct extent_io_tree *pinned_extents;
1381
1382         pending_del = &extent_root->fs_info->pending_del;
1383         pinned_extents = &extent_root->fs_info->pinned_extents;
1384
1385         while(1) {
1386                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1387                                             EXTENT_LOCKED);
1388                 if (ret)
1389                         break;
1390                 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1391                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1392                                   GFP_NOFS);
1393                 ret = __free_extent(trans, extent_root,
1394                                      start, end + 1 - start,
1395                                      extent_root->root_key.objectid,
1396                                      0, 0, 0, 0, 0);
1397                 if (ret)
1398                         err = ret;
1399         }
1400         return err;
1401 }
1402
1403 /*
1404  * remove an extent from the root, returns 0 on success
1405  */
1406 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1407                       *root, u64 bytenr, u64 num_bytes,
1408                       u64 root_objectid, u64 ref_generation,
1409                       u64 owner_objectid, u64 owner_offset, int pin)
1410 {
1411         struct btrfs_root *extent_root = root->fs_info->extent_root;
1412         int pending_ret;
1413         int ret;
1414
1415         WARN_ON(num_bytes < root->sectorsize);
1416         if (!root->ref_cows)
1417                 ref_generation = 0;
1418
1419         if (root == extent_root) {
1420                 pin_down_bytes(root, bytenr, num_bytes, 1);
1421                 return 0;
1422         }
1423         ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1424                             ref_generation, owner_objectid, owner_offset,
1425                             pin, pin == 0);
1426         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1427         return ret ? ret : pending_ret;
1428 }
1429
1430 static u64 stripe_align(struct btrfs_root *root, u64 val)
1431 {
1432         u64 mask = ((u64)root->stripesize - 1);
1433         u64 ret = (val + mask) & ~mask;
1434         return ret;
1435 }
1436
1437 /*
1438  * walks the btree of allocated extents and find a hole of a given size.
1439  * The key ins is changed to record the hole:
1440  * ins->objectid == block start
1441  * ins->flags = BTRFS_EXTENT_ITEM_KEY
1442  * ins->offset == number of blocks
1443  * Any available blocks before search_start are skipped.
1444  */
1445 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1446                                      struct btrfs_root *orig_root,
1447                                      u64 num_bytes, u64 empty_size,
1448                                      u64 search_start, u64 search_end,
1449                                      u64 hint_byte, struct btrfs_key *ins,
1450                                      u64 exclude_start, u64 exclude_nr,
1451                                      int data)
1452 {
1453         struct btrfs_path *path;
1454         struct btrfs_key key;
1455         u64 hole_size = 0;
1456         u64 aligned;
1457         int ret;
1458         int slot = 0;
1459         u64 last_byte = 0;
1460         u64 *last_ptr = NULL;
1461         u64 orig_search_start = search_start;
1462         int start_found;
1463         struct extent_buffer *l;
1464         struct btrfs_root * root = orig_root->fs_info->extent_root;
1465         struct btrfs_fs_info *info = root->fs_info;
1466         u64 total_needed = num_bytes;
1467         int level;
1468         struct btrfs_block_group_cache *block_group;
1469         int full_scan = 0;
1470         int wrapped = 0;
1471         int empty_cluster;
1472         u64 cached_start;
1473
1474         WARN_ON(num_bytes < root->sectorsize);
1475         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1476
1477         level = btrfs_header_level(root->node);
1478
1479         if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
1480                 data = BTRFS_BLOCK_GROUP_MIXED;
1481         }
1482
1483         if (search_end == (u64)-1)
1484                 search_end = btrfs_super_total_bytes(&info->super_copy);
1485         if (hint_byte) {
1486                 block_group = btrfs_lookup_block_group(info, hint_byte);
1487                 if (!block_group)
1488                         hint_byte = search_start;
1489                 block_group = btrfs_find_block_group(root, block_group,
1490                                                      hint_byte, data, 1);
1491         } else {
1492                 block_group = btrfs_find_block_group(root,
1493                                                      trans->block_group,
1494                                                      search_start, data, 1);
1495         }
1496
1497         total_needed += empty_size;
1498         path = btrfs_alloc_path();
1499 check_failed:
1500         if (!block_group) {
1501                 block_group = btrfs_lookup_block_group(info, search_start);
1502                 if (!block_group)
1503                         block_group = btrfs_lookup_block_group(info,
1504                                                        orig_search_start);
1505         }
1506         search_start = find_search_start(root, &block_group, search_start,
1507                                          total_needed, data);
1508         search_start = stripe_align(root, search_start);
1509         cached_start = search_start;
1510         btrfs_init_path(path);
1511         ins->objectid = search_start;
1512         ins->offset = 0;
1513         start_found = 0;
1514         path->reada = 2;
1515
1516         ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1517         if (ret < 0)
1518                 goto error;
1519         ret = find_previous_extent(root, path);
1520         if (ret < 0)
1521                 goto error;
1522         l = path->nodes[0];
1523         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1524         while (1) {
1525                 l = path->nodes[0];
1526                 slot = path->slots[0];
1527                 if (slot >= btrfs_header_nritems(l)) {
1528                         ret = btrfs_next_leaf(root, path);
1529                         if (ret == 0)
1530                                 continue;
1531                         if (ret < 0)
1532                                 goto error;
1533
1534                         search_start = max(search_start,
1535                                            block_group->key.objectid);
1536                         if (!start_found) {
1537                                 aligned = stripe_align(root, search_start);
1538                                 ins->objectid = aligned;
1539                                 if (aligned >= search_end) {
1540                                         ret = -ENOSPC;
1541                                         goto error;
1542                                 }
1543                                 ins->offset = search_end - aligned;
1544                                 start_found = 1;
1545                                 goto check_pending;
1546                         }
1547                         ins->objectid = stripe_align(root,
1548                                                      last_byte > search_start ?
1549                                                      last_byte : search_start);
1550                         if (search_end <= ins->objectid) {
1551                                 ret = -ENOSPC;
1552                                 goto error;
1553                         }
1554                         ins->offset = search_end - ins->objectid;
1555                         BUG_ON(ins->objectid >= search_end);
1556                         goto check_pending;
1557                 }
1558                 btrfs_item_key_to_cpu(l, &key, slot);
1559
1560                 if (key.objectid >= search_start && key.objectid > last_byte &&
1561                     start_found) {
1562                         if (last_byte < search_start)
1563                                 last_byte = search_start;
1564                         aligned = stripe_align(root, last_byte);
1565                         hole_size = key.objectid - aligned;
1566                         if (key.objectid > aligned && hole_size >= num_bytes) {
1567                                 ins->objectid = aligned;
1568                                 ins->offset = hole_size;
1569                                 goto check_pending;
1570                         }
1571                 }
1572                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1573                         if (!start_found && btrfs_key_type(&key) ==
1574                             BTRFS_BLOCK_GROUP_ITEM_KEY) {
1575                                 last_byte = key.objectid;
1576                                 start_found = 1;
1577                         }
1578                         goto next;
1579                 }
1580
1581
1582                 start_found = 1;
1583                 last_byte = key.objectid + key.offset;
1584
1585                 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1586                     last_byte >= block_group->key.objectid +
1587                     block_group->key.offset) {
1588                         btrfs_release_path(root, path);
1589                         search_start = block_group->key.objectid +
1590                                 block_group->key.offset;
1591                         goto new_group;
1592                 }
1593 next:
1594                 path->slots[0]++;
1595                 cond_resched();
1596         }
1597 check_pending:
1598         /* we have to make sure we didn't find an extent that has already
1599          * been allocated by the map tree or the original allocation
1600          */
1601         btrfs_release_path(root, path);
1602         BUG_ON(ins->objectid < search_start);
1603
1604         if (ins->objectid + num_bytes >= search_end)
1605                 goto enospc;
1606         if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1607             ins->objectid + num_bytes > block_group->
1608             key.objectid + block_group->key.offset) {
1609                 search_start = block_group->key.objectid +
1610                         block_group->key.offset;
1611                 goto new_group;
1612         }
1613         if (test_range_bit(&info->extent_ins, ins->objectid,
1614                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1615                 search_start = ins->objectid + num_bytes;
1616                 goto new_group;
1617         }
1618         if (test_range_bit(&info->pinned_extents, ins->objectid,
1619                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1620                 search_start = ins->objectid + num_bytes;
1621                 goto new_group;
1622         }
1623         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1624             ins->objectid < exclude_start + exclude_nr)) {
1625                 search_start = exclude_start + exclude_nr;
1626                 goto new_group;
1627         }
1628         if (!data) {
1629                 block_group = btrfs_lookup_block_group(info, ins->objectid);
1630                 if (block_group)
1631                         trans->block_group = block_group;
1632         }
1633         ins->offset = num_bytes;
1634         btrfs_free_path(path);
1635         return 0;
1636
1637 new_group:
1638         if (search_start + num_bytes >= search_end) {
1639 enospc:
1640                 search_start = orig_search_start;
1641                 if (full_scan) {
1642                         ret = -ENOSPC;
1643                         goto error;
1644                 }
1645                 if (wrapped) {
1646                         if (!full_scan)
1647                                 total_needed -= empty_size;
1648                         full_scan = 1;
1649                         data = BTRFS_BLOCK_GROUP_MIXED;
1650                 } else
1651                         wrapped = 1;
1652         }
1653         block_group = btrfs_lookup_block_group(info, search_start);
1654         cond_resched();
1655         block_group = btrfs_find_block_group(root, block_group,
1656                                              search_start, data, 0);
1657         goto check_failed;
1658
1659 error:
1660         btrfs_release_path(root, path);
1661         btrfs_free_path(path);
1662         return ret;
1663 }
1664 /*
1665  * finds a free extent and does all the dirty work required for allocation
1666  * returns the key for the extent through ins, and a tree buffer for
1667  * the first block of the extent through buf.
1668  *
1669  * returns 0 if everything worked, non-zero otherwise.
1670  */
1671 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1672                        struct btrfs_root *root,
1673                        u64 num_bytes, u64 root_objectid, u64 ref_generation,
1674                        u64 owner, u64 owner_offset,
1675                        u64 empty_size, u64 hint_byte,
1676                        u64 search_end, struct btrfs_key *ins, int data)
1677 {
1678         int ret;
1679         int pending_ret;
1680         u64 super_used;
1681         u64 root_used;
1682         u64 search_start = 0;
1683         u64 new_hint;
1684         u32 sizes[2];
1685         struct btrfs_fs_info *info = root->fs_info;
1686         struct btrfs_root *extent_root = info->extent_root;
1687         struct btrfs_extent_item *extent_item;
1688         struct btrfs_extent_ref *ref;
1689         struct btrfs_path *path;
1690         struct btrfs_key keys[2];
1691
1692         new_hint = max(hint_byte, root->fs_info->alloc_start);
1693         if (new_hint < btrfs_super_total_bytes(&info->super_copy))
1694                 hint_byte = new_hint;
1695
1696         WARN_ON(num_bytes < root->sectorsize);
1697         ret = find_free_extent(trans, root, num_bytes, empty_size,
1698                                search_start, search_end, hint_byte, ins,
1699                                trans->alloc_exclude_start,
1700                                trans->alloc_exclude_nr, data);
1701         BUG_ON(ret);
1702         if (ret)
1703                 return ret;
1704
1705         /* block accounting for super block */
1706         super_used = btrfs_super_bytes_used(&info->super_copy);
1707         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1708
1709         /* block accounting for root item */
1710         root_used = btrfs_root_used(&root->root_item);
1711         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1712
1713         clear_extent_dirty(&root->fs_info->free_space_cache,
1714                            ins->objectid, ins->objectid + ins->offset - 1,
1715                            GFP_NOFS);
1716
1717         if (root == extent_root) {
1718                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1719                                 ins->objectid + ins->offset - 1,
1720                                 EXTENT_LOCKED, GFP_NOFS);
1721                 WARN_ON(data == 1);
1722                 goto update_block;
1723         }
1724
1725         WARN_ON(trans->alloc_exclude_nr);
1726         trans->alloc_exclude_start = ins->objectid;
1727         trans->alloc_exclude_nr = ins->offset;
1728
1729         memcpy(&keys[0], ins, sizeof(*ins));
1730         keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1731                                          owner, owner_offset);
1732         keys[1].objectid = ins->objectid;
1733         keys[1].type = BTRFS_EXTENT_REF_KEY;
1734         sizes[0] = sizeof(*extent_item);
1735         sizes[1] = sizeof(*ref);
1736
1737         path = btrfs_alloc_path();
1738         BUG_ON(!path);
1739
1740         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1741                                        sizes, 2);
1742
1743         BUG_ON(ret);
1744         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1745                                      struct btrfs_extent_item);
1746         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1747         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1748                              struct btrfs_extent_ref);
1749
1750         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1751         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1752         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1753         btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1754
1755         btrfs_mark_buffer_dirty(path->nodes[0]);
1756
1757         trans->alloc_exclude_start = 0;
1758         trans->alloc_exclude_nr = 0;
1759         btrfs_free_path(path);
1760         finish_current_insert(trans, extent_root);
1761         pending_ret = del_pending_extents(trans, extent_root);
1762
1763         if (ret) {
1764                 return ret;
1765         }
1766         if (pending_ret) {
1767                 return pending_ret;
1768         }
1769
1770 update_block:
1771         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1772                                  data);
1773         if (ret) {
1774                 printk("update block group failed for %Lu %Lu\n",
1775                        ins->objectid, ins->offset);
1776                 BUG();
1777         }
1778         return 0;
1779 }
1780
1781 /*
1782  * helper function to allocate a block for a given tree
1783  * returns the tree buffer or NULL.
1784  */
1785 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1786                                              struct btrfs_root *root,
1787                                              u32 blocksize,
1788                                              u64 root_objectid, u64 hint,
1789                                              u64 empty_size)
1790 {
1791         u64 ref_generation;
1792
1793         if (root->ref_cows)
1794                 ref_generation = trans->transid;
1795         else
1796                 ref_generation = 0;
1797
1798
1799         return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1800                                         ref_generation, 0, 0, hint, empty_size);
1801 }
1802
1803 /*
1804  * helper function to allocate a block for a given tree
1805  * returns the tree buffer or NULL.
1806  */
1807 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1808                                              struct btrfs_root *root,
1809                                              u32 blocksize,
1810                                              u64 root_objectid,
1811                                              u64 ref_generation,
1812                                              u64 first_objectid,
1813                                              int level,
1814                                              u64 hint,
1815                                              u64 empty_size)
1816 {
1817         struct btrfs_key ins;
1818         int ret;
1819         struct extent_buffer *buf;
1820
1821         ret = btrfs_alloc_extent(trans, root, blocksize,
1822                                  root_objectid, ref_generation,
1823                                  level, first_objectid, empty_size, hint,
1824                                  (u64)-1, &ins, 0);
1825         if (ret) {
1826                 BUG_ON(ret > 0);
1827                 return ERR_PTR(ret);
1828         }
1829         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1830         if (!buf) {
1831                 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1832                                   root->root_key.objectid, ref_generation,
1833                                   0, 0, 0);
1834                 return ERR_PTR(-ENOMEM);
1835         }
1836         btrfs_set_header_generation(buf, trans->transid);
1837         clean_tree_block(trans, root, buf);
1838         wait_on_tree_block_writeback(root, buf);
1839         btrfs_set_buffer_uptodate(buf);
1840
1841         if (PageDirty(buf->first_page)) {
1842                 printk("page %lu dirty\n", buf->first_page->index);
1843                 WARN_ON(1);
1844         }
1845
1846         set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1847                          buf->start + buf->len - 1, GFP_NOFS);
1848         set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->io_tree,
1849                         buf->start, buf->start + buf->len - 1,
1850                         EXTENT_CSUM, GFP_NOFS);
1851         buf->flags |= EXTENT_CSUM;
1852         if (!btrfs_test_opt(root, SSD))
1853                 btrfs_set_buffer_defrag(buf);
1854         trans->blocks_used++;
1855         return buf;
1856 }
1857
1858 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1859                                   struct btrfs_root *root,
1860                                   struct extent_buffer *leaf)
1861 {
1862         u64 leaf_owner;
1863         u64 leaf_generation;
1864         struct btrfs_key key;
1865         struct btrfs_file_extent_item *fi;
1866         int i;
1867         int nritems;
1868         int ret;
1869
1870         BUG_ON(!btrfs_is_leaf(leaf));
1871         nritems = btrfs_header_nritems(leaf);
1872         leaf_owner = btrfs_header_owner(leaf);
1873         leaf_generation = btrfs_header_generation(leaf);
1874
1875         for (i = 0; i < nritems; i++) {
1876                 u64 disk_bytenr;
1877
1878                 btrfs_item_key_to_cpu(leaf, &key, i);
1879                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1880                         continue;
1881                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1882                 if (btrfs_file_extent_type(leaf, fi) ==
1883                     BTRFS_FILE_EXTENT_INLINE)
1884                         continue;
1885                 /*
1886                  * FIXME make sure to insert a trans record that
1887                  * repeats the snapshot del on crash
1888                  */
1889                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1890                 if (disk_bytenr == 0)
1891                         continue;
1892                 ret = btrfs_free_extent(trans, root, disk_bytenr,
1893                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
1894                                 leaf_owner, leaf_generation,
1895                                 key.objectid, key.offset, 0);
1896                 BUG_ON(ret);
1897         }
1898         return 0;
1899 }
1900
1901 static void noinline reada_walk_down(struct btrfs_root *root,
1902                                      struct extent_buffer *node,
1903                                      int slot)
1904 {
1905         u64 bytenr;
1906         u64 last = 0;
1907         u32 nritems;
1908         u32 refs;
1909         u32 blocksize;
1910         int ret;
1911         int i;
1912         int level;
1913         int skipped = 0;
1914
1915         nritems = btrfs_header_nritems(node);
1916         level = btrfs_header_level(node);
1917         if (level)
1918                 return;
1919
1920         for (i = slot; i < nritems && skipped < 32; i++) {
1921                 bytenr = btrfs_node_blockptr(node, i);
1922                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1923                              (last > bytenr && last - bytenr > 32 * 1024))) {
1924                         skipped++;
1925                         continue;
1926                 }
1927                 blocksize = btrfs_level_size(root, level - 1);
1928                 if (i != slot) {
1929                         ret = lookup_extent_ref(NULL, root, bytenr,
1930                                                 blocksize, &refs);
1931                         BUG_ON(ret);
1932                         if (refs != 1) {
1933                                 skipped++;
1934                                 continue;
1935                         }
1936                 }
1937                 mutex_unlock(&root->fs_info->fs_mutex);
1938                 ret = readahead_tree_block(root, bytenr, blocksize);
1939                 last = bytenr + blocksize;
1940                 cond_resched();
1941                 mutex_lock(&root->fs_info->fs_mutex);
1942                 if (ret)
1943                         break;
1944         }
1945 }
1946
1947 /*
1948  * helper function for drop_snapshot, this walks down the tree dropping ref
1949  * counts as it goes.
1950  */
1951 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1952                                    struct btrfs_root *root,
1953                                    struct btrfs_path *path, int *level)
1954 {
1955         u64 root_owner;
1956         u64 root_gen;
1957         u64 bytenr;
1958         struct extent_buffer *next;
1959         struct extent_buffer *cur;
1960         struct extent_buffer *parent;
1961         u32 blocksize;
1962         int ret;
1963         u32 refs;
1964
1965         WARN_ON(*level < 0);
1966         WARN_ON(*level >= BTRFS_MAX_LEVEL);
1967         ret = lookup_extent_ref(trans, root,
1968                                 path->nodes[*level]->start,
1969                                 path->nodes[*level]->len, &refs);
1970         BUG_ON(ret);
1971         if (refs > 1)
1972                 goto out;
1973
1974         /*
1975          * walk down to the last node level and free all the leaves
1976          */
1977         while(*level >= 0) {
1978                 WARN_ON(*level < 0);
1979                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1980                 cur = path->nodes[*level];
1981
1982                 if (btrfs_header_level(cur) != *level)
1983                         WARN_ON(1);
1984
1985                 if (path->slots[*level] >=
1986                     btrfs_header_nritems(cur))
1987                         break;
1988                 if (*level == 0) {
1989                         ret = drop_leaf_ref(trans, root, cur);
1990                         BUG_ON(ret);
1991                         break;
1992                 }
1993                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1994                 blocksize = btrfs_level_size(root, *level - 1);
1995                 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1996                 BUG_ON(ret);
1997                 if (refs != 1) {
1998                         parent = path->nodes[*level];
1999                         root_owner = btrfs_header_owner(parent);
2000                         root_gen = btrfs_header_generation(parent);
2001                         path->slots[*level]++;
2002                         ret = btrfs_free_extent(trans, root, bytenr,
2003                                                 blocksize, root_owner,
2004                                                 root_gen, 0, 0, 1);
2005                         BUG_ON(ret);
2006                         continue;
2007                 }
2008                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2009                 if (!next || !btrfs_buffer_uptodate(next)) {
2010                         free_extent_buffer(next);
2011                         reada_walk_down(root, cur, path->slots[*level]);
2012                         mutex_unlock(&root->fs_info->fs_mutex);
2013                         next = read_tree_block(root, bytenr, blocksize);
2014                         mutex_lock(&root->fs_info->fs_mutex);
2015
2016                         /* we dropped the lock, check one more time */
2017                         ret = lookup_extent_ref(trans, root, bytenr,
2018                                                 blocksize, &refs);
2019                         BUG_ON(ret);
2020                         if (refs != 1) {
2021                                 parent = path->nodes[*level];
2022                                 root_owner = btrfs_header_owner(parent);
2023                                 root_gen = btrfs_header_generation(parent);
2024
2025                                 path->slots[*level]++;
2026                                 free_extent_buffer(next);
2027                                 ret = btrfs_free_extent(trans, root, bytenr,
2028                                                         blocksize,
2029                                                         root_owner,
2030                                                         root_gen, 0, 0, 1);
2031                                 BUG_ON(ret);
2032                                 continue;
2033                         }
2034                 }
2035                 WARN_ON(*level <= 0);
2036                 if (path->nodes[*level-1])
2037                         free_extent_buffer(path->nodes[*level-1]);
2038                 path->nodes[*level-1] = next;
2039                 *level = btrfs_header_level(next);
2040                 path->slots[*level] = 0;
2041         }
2042 out:
2043         WARN_ON(*level < 0);
2044         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2045
2046         if (path->nodes[*level] == root->node) {
2047                 root_owner = root->root_key.objectid;
2048                 parent = path->nodes[*level];
2049         } else {
2050                 parent = path->nodes[*level + 1];
2051                 root_owner = btrfs_header_owner(parent);
2052         }
2053
2054         root_gen = btrfs_header_generation(parent);
2055         ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2056                                 path->nodes[*level]->len,
2057                                 root_owner, root_gen, 0, 0, 1);
2058         free_extent_buffer(path->nodes[*level]);
2059         path->nodes[*level] = NULL;
2060         *level += 1;
2061         BUG_ON(ret);
2062         return 0;
2063 }
2064
2065 /*
2066  * helper for dropping snapshots.  This walks back up the tree in the path
2067  * to find the first node higher up where we haven't yet gone through
2068  * all the slots
2069  */
2070 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2071                                  struct btrfs_root *root,
2072                                  struct btrfs_path *path, int *level)
2073 {
2074         u64 root_owner;
2075         u64 root_gen;
2076         struct btrfs_root_item *root_item = &root->root_item;
2077         int i;
2078         int slot;
2079         int ret;
2080
2081         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2082                 slot = path->slots[i];
2083                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2084                         struct extent_buffer *node;
2085                         struct btrfs_disk_key disk_key;
2086                         node = path->nodes[i];
2087                         path->slots[i]++;
2088                         *level = i;
2089                         WARN_ON(*level == 0);
2090                         btrfs_node_key(node, &disk_key, path->slots[i]);
2091                         memcpy(&root_item->drop_progress,
2092                                &disk_key, sizeof(disk_key));
2093                         root_item->drop_level = i;
2094                         return 0;
2095                 } else {
2096                         if (path->nodes[*level] == root->node) {
2097                                 root_owner = root->root_key.objectid;
2098                                 root_gen =
2099                                    btrfs_header_generation(path->nodes[*level]);
2100                         } else {
2101                                 struct extent_buffer *node;
2102                                 node = path->nodes[*level + 1];
2103                                 root_owner = btrfs_header_owner(node);
2104                                 root_gen = btrfs_header_generation(node);
2105                         }
2106                         ret = btrfs_free_extent(trans, root,
2107                                                 path->nodes[*level]->start,
2108                                                 path->nodes[*level]->len,
2109                                                 root_owner, root_gen, 0, 0, 1);
2110                         BUG_ON(ret);
2111                         free_extent_buffer(path->nodes[*level]);
2112                         path->nodes[*level] = NULL;
2113                         *level = i + 1;
2114                 }
2115         }
2116         return 1;
2117 }
2118
2119 /*
2120  * drop the reference count on the tree rooted at 'snap'.  This traverses
2121  * the tree freeing any blocks that have a ref count of zero after being
2122  * decremented.
2123  */
2124 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2125                         *root)
2126 {
2127         int ret = 0;
2128         int wret;
2129         int level;
2130         struct btrfs_path *path;
2131         int i;
2132         int orig_level;
2133         struct btrfs_root_item *root_item = &root->root_item;
2134
2135         path = btrfs_alloc_path();
2136         BUG_ON(!path);
2137
2138         level = btrfs_header_level(root->node);
2139         orig_level = level;
2140         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2141                 path->nodes[level] = root->node;
2142                 extent_buffer_get(root->node);
2143                 path->slots[level] = 0;
2144         } else {
2145                 struct btrfs_key key;
2146                 struct btrfs_disk_key found_key;
2147                 struct extent_buffer *node;
2148
2149                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2150                 level = root_item->drop_level;
2151                 path->lowest_level = level;
2152                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2153                 if (wret < 0) {
2154                         ret = wret;
2155                         goto out;
2156                 }
2157                 node = path->nodes[level];
2158                 btrfs_node_key(node, &found_key, path->slots[level]);
2159                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2160                                sizeof(found_key)));
2161         }
2162         while(1) {
2163                 wret = walk_down_tree(trans, root, path, &level);
2164                 if (wret > 0)
2165                         break;
2166                 if (wret < 0)
2167                         ret = wret;
2168
2169                 wret = walk_up_tree(trans, root, path, &level);
2170                 if (wret > 0)
2171                         break;
2172                 if (wret < 0)
2173                         ret = wret;
2174                 ret = -EAGAIN;
2175                 break;
2176         }
2177         for (i = 0; i <= orig_level; i++) {
2178                 if (path->nodes[i]) {
2179                         free_extent_buffer(path->nodes[i]);
2180                         path->nodes[i] = NULL;
2181                 }
2182         }
2183 out:
2184         btrfs_free_path(path);
2185         return ret;
2186 }
2187
2188 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2189 {
2190         u64 start;
2191         u64 end;
2192         u64 ptr;
2193         int ret;
2194         while(1) {
2195                 ret = find_first_extent_bit(&info->block_group_cache, 0,
2196                                             &start, &end, (unsigned int)-1);
2197                 if (ret)
2198                         break;
2199                 ret = get_state_private(&info->block_group_cache, start, &ptr);
2200                 if (!ret)
2201                         kfree((void *)(unsigned long)ptr);
2202                 clear_extent_bits(&info->block_group_cache, start,
2203                                   end, (unsigned int)-1, GFP_NOFS);
2204         }
2205         while(1) {
2206                 ret = find_first_extent_bit(&info->free_space_cache, 0,
2207                                             &start, &end, EXTENT_DIRTY);
2208                 if (ret)
2209                         break;
2210                 clear_extent_dirty(&info->free_space_cache, start,
2211                                    end, GFP_NOFS);
2212         }
2213         return 0;
2214 }
2215
2216 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2217                                          u64 len)
2218 {
2219         u64 page_start;
2220         u64 page_end;
2221         u64 delalloc_start;
2222         u64 existing_delalloc;
2223         unsigned long last_index;
2224         unsigned long i;
2225         struct page *page;
2226         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2227         struct file_ra_state *ra;
2228
2229         ra = kzalloc(sizeof(*ra), GFP_NOFS);
2230
2231         mutex_lock(&inode->i_mutex);
2232         i = start >> PAGE_CACHE_SHIFT;
2233         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2234
2235         file_ra_state_init(ra, inode->i_mapping);
2236         btrfs_force_ra(inode->i_mapping, ra, NULL, i, last_index);
2237         kfree(ra);
2238
2239         for (; i <= last_index; i++) {
2240                 page = grab_cache_page(inode->i_mapping, i);
2241                 if (!page)
2242                         goto out_unlock;
2243                 if (!PageUptodate(page)) {
2244                         btrfs_readpage(NULL, page);
2245                         lock_page(page);
2246                         if (!PageUptodate(page)) {
2247                                 unlock_page(page);
2248                                 page_cache_release(page);
2249                                 goto out_unlock;
2250                         }
2251                 }
2252                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2253                 page_end = page_start + PAGE_CACHE_SIZE - 1;
2254
2255                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2256
2257                 delalloc_start = page_start;
2258                 existing_delalloc = count_range_bits(io_tree,
2259                                              &delalloc_start, page_end,
2260                                              PAGE_CACHE_SIZE, EXTENT_DELALLOC);
2261
2262                 set_extent_delalloc(io_tree, page_start,
2263                                     page_end, GFP_NOFS);
2264
2265                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2266                 set_page_dirty(page);
2267                 unlock_page(page);
2268                 page_cache_release(page);
2269         }
2270
2271 out_unlock:
2272         mutex_unlock(&inode->i_mutex);
2273         return 0;
2274 }
2275
2276 /*
2277  * note, this releases the path
2278  */
2279 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2280                                   struct btrfs_path *path,
2281                                   struct btrfs_key *extent_key)
2282 {
2283         struct inode *inode;
2284         struct btrfs_root *found_root;
2285         struct btrfs_key *root_location;
2286         struct btrfs_extent_ref *ref;
2287         u64 ref_root;
2288         u64 ref_gen;
2289         u64 ref_objectid;
2290         u64 ref_offset;
2291         int ret;
2292
2293         ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2294                              struct btrfs_extent_ref);
2295         ref_root = btrfs_ref_root(path->nodes[0], ref);
2296         ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2297         ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2298         ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2299         btrfs_release_path(extent_root, path);
2300
2301         root_location = kmalloc(sizeof(*root_location), GFP_NOFS);
2302         root_location->objectid = ref_root;
2303         if (ref_gen == 0)
2304                 root_location->offset = 0;
2305         else
2306                 root_location->offset = (u64)-1;
2307         root_location->type = BTRFS_ROOT_ITEM_KEY;
2308
2309         found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2310                                                 root_location);
2311         BUG_ON(!found_root);
2312         kfree(root_location);
2313
2314         if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2315                 mutex_unlock(&extent_root->fs_info->fs_mutex);
2316                 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2317                                           ref_objectid, found_root);
2318                 if (inode->i_state & I_NEW) {
2319                         /* the inode and parent dir are two different roots */
2320                         BTRFS_I(inode)->root = found_root;
2321                         BTRFS_I(inode)->location.objectid = ref_objectid;
2322                         BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2323                         BTRFS_I(inode)->location.offset = 0;
2324                         btrfs_read_locked_inode(inode);
2325                         unlock_new_inode(inode);
2326
2327                 }
2328                 /* this can happen if the reference is not against
2329                  * the latest version of the tree root
2330                  */
2331                 if (is_bad_inode(inode)) {
2332                         mutex_lock(&extent_root->fs_info->fs_mutex);
2333                         goto out;
2334                 }
2335                 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2336                 /* FIXME, data=ordered will help get rid of this */
2337                 filemap_fdatawrite(inode->i_mapping);
2338                 iput(inode);
2339                 mutex_lock(&extent_root->fs_info->fs_mutex);
2340         } else {
2341                 struct btrfs_trans_handle *trans;
2342                 struct btrfs_key found_key;
2343                 struct extent_buffer *eb;
2344                 int level;
2345                 int i;
2346
2347                 trans = btrfs_start_transaction(found_root, 1);
2348                 eb = read_tree_block(found_root, extent_key->objectid,
2349                                      extent_key->offset);
2350                 level = btrfs_header_level(eb);
2351
2352                 if (level == 0)
2353                         btrfs_item_key_to_cpu(eb, &found_key, 0);
2354                 else
2355                         btrfs_node_key_to_cpu(eb, &found_key, 0);
2356
2357                 free_extent_buffer(eb);
2358
2359                 path->lowest_level = level;
2360                 path->reada = 2;
2361                 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2362                                         0, 1);
2363                 path->lowest_level = 0;
2364                 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2365                         if (!path->nodes[i])
2366                                 break;
2367                         free_extent_buffer(path->nodes[i]);
2368                         path->nodes[i] = NULL;
2369                 }
2370                 btrfs_release_path(found_root, path);
2371                 btrfs_end_transaction(trans, found_root);
2372         }
2373
2374 out:
2375         return 0;
2376 }
2377
2378 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2379                                         struct btrfs_path *path,
2380                                         struct btrfs_key *extent_key)
2381 {
2382         struct btrfs_key key;
2383         struct btrfs_key found_key;
2384         struct extent_buffer *leaf;
2385         u32 nritems;
2386         u32 item_size;
2387         int ret = 0;
2388
2389         key.objectid = extent_key->objectid;
2390         key.type = BTRFS_EXTENT_REF_KEY;
2391         key.offset = 0;
2392
2393         while(1) {
2394                 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2395
2396                 if (ret < 0)
2397                         goto out;
2398
2399                 ret = 0;
2400                 leaf = path->nodes[0];
2401                 nritems = btrfs_header_nritems(leaf);
2402                 if (path->slots[0] == nritems)
2403                         goto out;
2404
2405                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2406                 if (found_key.objectid != extent_key->objectid)
2407                         break;
2408
2409                 if (found_key.type != BTRFS_EXTENT_REF_KEY)
2410                         break;
2411
2412                 key.offset = found_key.offset + 1;
2413                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2414
2415                 ret = relocate_one_reference(extent_root, path, extent_key);
2416                 if (ret)
2417                         goto out;
2418         }
2419         ret = 0;
2420 out:
2421         btrfs_release_path(extent_root, path);
2422         return ret;
2423 }
2424
2425 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
2426 {
2427         struct btrfs_trans_handle *trans;
2428         struct btrfs_root *tree_root = root->fs_info->tree_root;
2429         struct btrfs_path *path;
2430         u64 cur_byte;
2431         u64 total_found;
2432         struct btrfs_fs_info *info = root->fs_info;
2433         struct extent_io_tree *block_group_cache;
2434         struct btrfs_key key;
2435         struct btrfs_key found_key;
2436         struct extent_buffer *leaf;
2437         u32 nritems;
2438         int ret;
2439         int progress = 0;
2440
2441         btrfs_set_super_total_bytes(&info->super_copy, new_size);
2442         clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2443                            GFP_NOFS);
2444         block_group_cache = &info->block_group_cache;
2445         path = btrfs_alloc_path();
2446         root = root->fs_info->extent_root;
2447         path->reada = 2;
2448
2449 again:
2450         total_found = 0;
2451         key.objectid = new_size;
2452         key.offset = 0;
2453         key.type = 0;
2454         cur_byte = key.objectid;
2455
2456         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2457         if (ret < 0)
2458                 goto out;
2459
2460         ret = find_previous_extent(root, path);
2461         if (ret < 0)
2462                 goto out;
2463         if (ret == 0) {
2464                 leaf = path->nodes[0];
2465                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2466                 if (found_key.objectid + found_key.offset > new_size) {
2467                         cur_byte = found_key.objectid;
2468                         key.objectid = cur_byte;
2469                 }
2470         }
2471         btrfs_release_path(root, path);
2472
2473         while(1) {
2474                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2475                 if (ret < 0)
2476                         goto out;
2477
2478                 leaf = path->nodes[0];
2479                 nritems = btrfs_header_nritems(leaf);
2480 next:
2481                 if (path->slots[0] >= nritems) {
2482                         ret = btrfs_next_leaf(root, path);
2483                         if (ret < 0)
2484                                 goto out;
2485                         if (ret == 1) {
2486                                 ret = 0;
2487                                 break;
2488                         }
2489                         leaf = path->nodes[0];
2490                         nritems = btrfs_header_nritems(leaf);
2491                 }
2492
2493                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2494
2495                 if (progress && need_resched()) {
2496                         memcpy(&key, &found_key, sizeof(key));
2497                         mutex_unlock(&root->fs_info->fs_mutex);
2498                         cond_resched();
2499                         mutex_lock(&root->fs_info->fs_mutex);
2500                         btrfs_release_path(root, path);
2501                         btrfs_search_slot(NULL, root, &key, path, 0, 0);
2502                         progress = 0;
2503                         goto next;
2504                 }
2505                 progress = 1;
2506
2507                 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
2508                     found_key.objectid + found_key.offset <= cur_byte) {
2509                         path->slots[0]++;
2510                         goto next;
2511                 }
2512
2513                 total_found++;
2514                 cur_byte = found_key.objectid + found_key.offset;
2515                 key.objectid = cur_byte;
2516                 btrfs_release_path(root, path);
2517                 ret = relocate_one_extent(root, path, &found_key);
2518         }
2519
2520         btrfs_release_path(root, path);
2521
2522         if (total_found > 0) {
2523                 trans = btrfs_start_transaction(tree_root, 1);
2524                 btrfs_commit_transaction(trans, tree_root);
2525
2526                 mutex_unlock(&root->fs_info->fs_mutex);
2527                 btrfs_clean_old_snapshots(tree_root);
2528                 mutex_lock(&root->fs_info->fs_mutex);
2529
2530                 trans = btrfs_start_transaction(tree_root, 1);
2531                 btrfs_commit_transaction(trans, tree_root);
2532                 goto again;
2533         }
2534
2535         trans = btrfs_start_transaction(root, 1);
2536         key.objectid = new_size;
2537         key.offset = 0;
2538         key.type = 0;
2539         while(1) {
2540                 u64 ptr;
2541
2542                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2543                 if (ret < 0)
2544                         goto out;
2545
2546                 leaf = path->nodes[0];
2547                 nritems = btrfs_header_nritems(leaf);
2548 bg_next:
2549                 if (path->slots[0] >= nritems) {
2550                         ret = btrfs_next_leaf(root, path);
2551                         if (ret < 0)
2552                                 break;
2553                         if (ret == 1) {
2554                                 ret = 0;
2555                                 break;
2556                         }
2557                         leaf = path->nodes[0];
2558                         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2559
2560                         /*
2561                          * btrfs_next_leaf doesn't cow buffers, we have to
2562                          * do the search again
2563                          */
2564                         memcpy(&key, &found_key, sizeof(key));
2565                         btrfs_release_path(root, path);
2566                         goto resched_check;
2567                 }
2568
2569                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2570                 if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {
2571                         printk("shrinker found key %Lu %u %Lu\n",
2572                                 found_key.objectid, found_key.type,
2573                                 found_key.offset);
2574                         path->slots[0]++;
2575                         goto bg_next;
2576                 }
2577                 ret = get_state_private(&info->block_group_cache,
2578                                         found_key.objectid, &ptr);
2579                 if (!ret)
2580                         kfree((void *)(unsigned long)ptr);
2581
2582                 clear_extent_bits(&info->block_group_cache, found_key.objectid,
2583                                   found_key.objectid + found_key.offset - 1,
2584                                   (unsigned int)-1, GFP_NOFS);
2585
2586                 key.objectid = found_key.objectid + 1;
2587                 btrfs_del_item(trans, root, path);
2588                 btrfs_release_path(root, path);
2589 resched_check:
2590                 if (need_resched()) {
2591                         mutex_unlock(&root->fs_info->fs_mutex);
2592                         cond_resched();
2593                         mutex_lock(&root->fs_info->fs_mutex);
2594                 }
2595         }
2596         clear_extent_dirty(&info->free_space_cache, new_size, (u64)-1,
2597                            GFP_NOFS);
2598         btrfs_commit_transaction(trans, root);
2599 out:
2600         btrfs_free_path(path);
2601         return ret;
2602 }
2603
2604 int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
2605                            struct btrfs_root *root, u64 new_size)
2606 {
2607         struct btrfs_path *path;
2608         u64 nr = 0;
2609         u64 cur_byte;
2610         u64 old_size;
2611         unsigned long rem;
2612         struct btrfs_block_group_cache *cache;
2613         struct btrfs_block_group_item *item;
2614         struct btrfs_fs_info *info = root->fs_info;
2615         struct extent_io_tree *block_group_cache;
2616         struct btrfs_key key;
2617         struct extent_buffer *leaf;
2618         int ret;
2619         int bit;
2620
2621         old_size = btrfs_super_total_bytes(&info->super_copy);
2622         block_group_cache = &info->block_group_cache;
2623
2624         root = info->extent_root;
2625
2626         cache = btrfs_lookup_block_group(root->fs_info, old_size - 1);
2627
2628         cur_byte = cache->key.objectid + cache->key.offset;
2629         if (cur_byte >= new_size)
2630                 goto set_size;
2631
2632         key.offset = BTRFS_BLOCK_GROUP_SIZE;
2633         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2634
2635         path = btrfs_alloc_path();
2636         if (!path)
2637                 return -ENOMEM;
2638
2639         while(cur_byte < new_size) {
2640                 key.objectid = cur_byte;
2641                 ret = btrfs_insert_empty_item(trans, root, path, &key,
2642                                         sizeof(struct btrfs_block_group_item));
2643                 BUG_ON(ret);
2644                 leaf = path->nodes[0];
2645                 item = btrfs_item_ptr(leaf, path->slots[0],
2646                                       struct btrfs_block_group_item);
2647
2648                 btrfs_set_disk_block_group_used(leaf, item, 0);
2649                 div_long_long_rem(nr, 3, &rem);
2650                 if (rem) {
2651                         btrfs_set_disk_block_group_flags(leaf, item,
2652                                                  BTRFS_BLOCK_GROUP_DATA);
2653                 } else {
2654                         btrfs_set_disk_block_group_flags(leaf, item, 0);
2655                 }
2656                 nr++;
2657
2658                 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2659                 BUG_ON(!cache);
2660
2661                 read_extent_buffer(leaf, &cache->item, (unsigned long)item,
2662                                    sizeof(cache->item));
2663
2664                 memcpy(&cache->key, &key, sizeof(key));
2665                 cache->cached = 0;
2666                 cache->pinned = 0;
2667                 cur_byte = key.objectid + key.offset;
2668                 btrfs_release_path(root, path);
2669
2670                 if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2671                         bit = BLOCK_GROUP_DATA;
2672                         cache->data = BTRFS_BLOCK_GROUP_DATA;
2673                 } else {
2674                         bit = BLOCK_GROUP_METADATA;
2675                         cache->data = 0;
2676                 }
2677
2678                 /* use EXTENT_LOCKED to prevent merging */
2679                 set_extent_bits(block_group_cache, key.objectid,
2680                                 key.objectid + key.offset - 1,
2681                                 bit | EXTENT_LOCKED, GFP_NOFS);
2682                 set_state_private(block_group_cache, key.objectid,
2683                                   (unsigned long)cache);
2684         }
2685         btrfs_free_path(path);
2686 set_size:
2687         btrfs_set_super_total_bytes(&info->super_copy, new_size);
2688         return 0;
2689 }
2690
2691 int btrfs_read_block_groups(struct btrfs_root *root)
2692 {
2693         struct btrfs_path *path;
2694         int ret;
2695         int err = 0;
2696         int bit;
2697         struct btrfs_block_group_cache *cache;
2698         struct btrfs_fs_info *info = root->fs_info;
2699         struct extent_io_tree *block_group_cache;
2700         struct btrfs_key key;
2701         struct btrfs_key found_key;
2702         struct extent_buffer *leaf;
2703
2704         block_group_cache = &info->block_group_cache;
2705
2706         root = info->extent_root;
2707         key.objectid = 0;
2708         key.offset = BTRFS_BLOCK_GROUP_SIZE;
2709         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2710
2711         path = btrfs_alloc_path();
2712         if (!path)
2713                 return -ENOMEM;
2714
2715         while(1) {
2716                 ret = btrfs_search_slot(NULL, info->extent_root,
2717                                         &key, path, 0, 0);
2718                 if (ret != 0) {
2719                         err = ret;
2720                         break;
2721                 }
2722                 leaf = path->nodes[0];
2723                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2724                 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2725                 if (!cache) {
2726                         err = -1;
2727                         break;
2728                 }
2729
2730                 read_extent_buffer(leaf, &cache->item,
2731                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
2732                                    sizeof(cache->item));
2733                 memcpy(&cache->key, &found_key, sizeof(found_key));
2734                 cache->cached = 0;
2735                 cache->pinned = 0;
2736                 key.objectid = found_key.objectid + found_key.offset;
2737                 btrfs_release_path(root, path);
2738
2739                 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
2740                         bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
2741                         cache->data = BTRFS_BLOCK_GROUP_MIXED;
2742                 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
2743                         bit = BLOCK_GROUP_DATA;
2744                         cache->data = BTRFS_BLOCK_GROUP_DATA;
2745                 } else {
2746                         bit = BLOCK_GROUP_METADATA;
2747                         cache->data = 0;
2748                 }
2749
2750                 /* use EXTENT_LOCKED to prevent merging */
2751                 set_extent_bits(block_group_cache, found_key.objectid,
2752                                 found_key.objectid + found_key.offset - 1,
2753                                 bit | EXTENT_LOCKED, GFP_NOFS);
2754                 set_state_private(block_group_cache, found_key.objectid,
2755                                   (unsigned long)cache);
2756
2757                 if (key.objectid >=
2758                     btrfs_super_total_bytes(&info->super_copy))
2759                         break;
2760         }
2761
2762         btrfs_free_path(path);
2763         return 0;
2764 }