git.oblomov.eu Git - 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 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include "compat.h"
  25 #include "hash.h"
  26 #include "crc32c.h"
  27 #include "ctree.h"
  28 #include "disk-io.h"
  29 #include "print-tree.h"
  30 #include "transaction.h"
  31 #include "volumes.h"
  32 #include "locking.h"
  33 #include "ref-cache.h"
  34
  35 #define PENDING_EXTENT_INSERT 0
  36 #define PENDING_EXTENT_DELETE 1
  37 #define PENDING_BACKREF_UPDATE 2
  38
  39 struct pending_extent_op {
  40         int type;
  41         u64 bytenr;
  42         u64 num_bytes;
  43         u64 parent;
  44         u64 orig_parent;
  45         u64 generation;
  46         u64 orig_generation;
  47         int level;
  48         struct list_head list;
  49         int del;
  50 };
  51
  52 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
  53                                          struct btrfs_root *root, u64 parent,
  54                                          u64 root_objectid, u64 ref_generation,
  55                                          u64 owner, struct btrfs_key *ins,
  56                                          int ref_mod);
  57 static int update_reserved_extents(struct btrfs_root *root,
  58                                    u64 bytenr, u64 num, int reserve);
  59 static int update_block_group(struct btrfs_trans_handle *trans,
  60                               struct btrfs_root *root,
  61                               u64 bytenr, u64 num_bytes, int alloc,
  62                               int mark_free);
  63 static noinline int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  64                                         struct btrfs_root *root,
  65                                         u64 bytenr, u64 num_bytes, u64 parent,
  66                                         u64 root_objectid, u64 ref_generation,
  67                                         u64 owner_objectid, int pin,
  68                                         int ref_to_drop);
  69
  70 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  71                           struct btrfs_root *extent_root, u64 alloc_bytes,
  72                           u64 flags, int force);
  73
  74 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  75 {
  76         return (cache->flags & bits) == bits;
  77 }
  78
  79 /*
  80  * this adds the block group to the fs_info rb tree for the block group
  81  * cache
  82  */
  83 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
  84                                 struct btrfs_block_group_cache *block_group)
  85 {
  86         struct rb_node **p;
  87         struct rb_node *parent = NULL;
  88         struct btrfs_block_group_cache *cache;
  89
  90         spin_lock(&info->block_group_cache_lock);
  91         p = &info->block_group_cache_tree.rb_node;
  92
  93         while (*p) {
  94                 parent = *p;
  95                 cache = rb_entry(parent, struct btrfs_block_group_cache,
  96                                  cache_node);
  97                 if (block_group->key.objectid < cache->key.objectid) {
  98                         p = &(*p)->rb_left;
  99                 } else if (block_group->key.objectid > cache->key.objectid) {
 100                         p = &(*p)->rb_right;
 101                 } else {
 102                         spin_unlock(&info->block_group_cache_lock);
 103                         return -EEXIST;
 104                 }
 105         }
 106
 107         rb_link_node(&block_group->cache_node, parent, p);
 108         rb_insert_color(&block_group->cache_node,
 109                         &info->block_group_cache_tree);
 110         spin_unlock(&info->block_group_cache_lock);
 111
 112         return 0;
 113 }
 114
 115 /*
 116  * This will return the block group at or after bytenr if contains is 0, else
 117  * it will return the block group that contains the bytenr
 118  */
 119 static struct btrfs_block_group_cache *
 120 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 121                               int contains)
 122 {
 123         struct btrfs_block_group_cache *cache, *ret = NULL;
 124         struct rb_node *n;
 125         u64 end, start;
 126
 127         spin_lock(&info->block_group_cache_lock);
 128         n = info->block_group_cache_tree.rb_node;
 129
 130         while (n) {
 131                 cache = rb_entry(n, struct btrfs_block_group_cache,
 132                                  cache_node);
 133                 end = cache->key.objectid + cache->key.offset - 1;
 134                 start = cache->key.objectid;
 135
 136                 if (bytenr < start) {
 137                         if (!contains && (!ret || start < ret->key.objectid))
 138                                 ret = cache;
 139                         n = n->rb_left;
 140                 } else if (bytenr > start) {
 141                         if (contains && bytenr <= end) {
 142                                 ret = cache;
 143                                 break;
 144                         }
 145                         n = n->rb_right;
 146                 } else {
 147                         ret = cache;
 148                         break;
 149                 }
 150         }
 151         if (ret)
 152                 atomic_inc(&ret->count);
 153         spin_unlock(&info->block_group_cache_lock);
 154
 155         return ret;
 156 }
 157
 158 /*
 159  * this is only called by cache_block_group, since we could have freed extents
 160  * we need to check the pinned_extents for any extents that can't be used yet
 161  * since their free space will be released as soon as the transaction commits.
 162  */
 163 static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 164                               struct btrfs_fs_info *info, u64 start, u64 end)
 165 {
 166         u64 extent_start, extent_end, size;
 167         int ret;
 168
 169         mutex_lock(&info->pinned_mutex);
 170         while (start < end) {
 171                 ret = find_first_extent_bit(&info->pinned_extents, start,
 172                                             &extent_start, &extent_end,
 173                                             EXTENT_DIRTY);
 174                 if (ret)
 175                         break;
 176
 177                 if (extent_start == start) {
 178                         start = extent_end + 1;
 179                 } else if (extent_start > start && extent_start < end) {
 180                         size = extent_start - start;
 181                         ret = btrfs_add_free_space(block_group, start,
 182                                                    size);
 183                         BUG_ON(ret);
 184                         start = extent_end + 1;
 185                 } else {
 186                         break;
 187                 }
 188         }
 189
 190         if (start < end) {
 191                 size = end - start;
 192                 ret = btrfs_add_free_space(block_group, start, size);
 193                 BUG_ON(ret);
 194         }
 195         mutex_unlock(&info->pinned_mutex);
 196
 197         return 0;
 198 }
 199
 200 static int remove_sb_from_cache(struct btrfs_root *root,
 201                                 struct btrfs_block_group_cache *cache)
 202 {
 203         u64 bytenr;
 204         u64 *logical;
 205         int stripe_len;
 206         int i, nr, ret;
 207
 208         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 209                 bytenr = btrfs_sb_offset(i);
 210                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 211                                        cache->key.objectid, bytenr, 0,
 212                                        &logical, &nr, &stripe_len);
 213                 BUG_ON(ret);
 214                 while (nr--) {
 215                         btrfs_remove_free_space(cache, logical[nr],
 216                                                 stripe_len);
 217                 }
 218                 kfree(logical);
 219         }
 220         return 0;
 221 }
 222
 223 static int cache_block_group(struct btrfs_root *root,
 224                              struct btrfs_block_group_cache *block_group)
 225 {
 226         struct btrfs_path *path;
 227         int ret = 0;
 228         struct btrfs_key key;
 229         struct extent_buffer *leaf;
 230         int slot;
 231         u64 last;
 232
 233         if (!block_group)
 234                 return 0;
 235
 236         root = root->fs_info->extent_root;
 237
 238         if (block_group->cached)
 239                 return 0;
 240
 241         path = btrfs_alloc_path();
 242         if (!path)
 243                 return -ENOMEM;
 244
 245         path->reada = 2;
 246         /*
 247          * we get into deadlocks with paths held by callers of this function.
 248          * since the alloc_mutex is protecting things right now, just
 249          * skip the locking here
 250          */
 251         path->skip_locking = 1;
 252         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 253         key.objectid = last;
 254         key.offset = 0;
 255         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 256         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 257         if (ret < 0)
 258                 goto err;
 259
 260         while (1) {
 261                 leaf = path->nodes[0];
 262                 slot = path->slots[0];
 263                 if (slot >= btrfs_header_nritems(leaf)) {
 264                         ret = btrfs_next_leaf(root, path);
 265                         if (ret < 0)
 266                                 goto err;
 267                         if (ret == 0)
 268                                 continue;
 269                         else
 270                                 break;
 271                 }
 272                 btrfs_item_key_to_cpu(leaf, &key, slot);
 273                 if (key.objectid < block_group->key.objectid)
 274                         goto next;
 275
 276                 if (key.objectid >= block_group->key.objectid +
 277                     block_group->key.offset)
 278                         break;
 279
 280                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 281                         add_new_free_space(block_group, root->fs_info, last,
 282                                            key.objectid);
 283
 284                         last = key.objectid + key.offset;
 285                 }
 286 next:
 287                 path->slots[0]++;
 288         }
 289
 290         add_new_free_space(block_group, root->fs_info, last,
 291                            block_group->key.objectid +
 292                            block_group->key.offset);
 293
 294         remove_sb_from_cache(root, block_group);
 295         block_group->cached = 1;
 296         ret = 0;
 297 err:
 298         btrfs_free_path(path);
 299         return ret;
 300 }
 301
 302 /*
 303  * return the block group that starts at or after bytenr
 304  */
 305 static struct btrfs_block_group_cache *
 306 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 307 {
 308         struct btrfs_block_group_cache *cache;
 309
 310         cache = block_group_cache_tree_search(info, bytenr, 0);
 311
 312         return cache;
 313 }
 314
 315 /*
 316  * return the block group that contains teh given bytenr
 317  */
 318 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 319                                                  struct btrfs_fs_info *info,
 320                                                  u64 bytenr)
 321 {
 322         struct btrfs_block_group_cache *cache;
 323
 324         cache = block_group_cache_tree_search(info, bytenr, 1);
 325
 326         return cache;
 327 }
 328
 329 static inline void put_block_group(struct btrfs_block_group_cache *cache)
 330 {
 331         if (atomic_dec_and_test(&cache->count))
 332                 kfree(cache);
 333 }
 334
 335 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 336                                                   u64 flags)
 337 {
 338         struct list_head *head = &info->space_info;
 339         struct btrfs_space_info *found;
 340
 341         rcu_read_lock();
 342         list_for_each_entry_rcu(found, head, list) {
 343                 if (found->flags == flags) {
 344                         rcu_read_unlock();
 345                         return found;
 346                 }
 347         }
 348         rcu_read_unlock();
 349         return NULL;
 350 }
 351
 352 /*
 353  * after adding space to the filesystem, we need to clear the full flags
 354  * on all the space infos.
 355  */
 356 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 357 {
 358         struct list_head *head = &info->space_info;
 359         struct btrfs_space_info *found;
 360
 361         rcu_read_lock();
 362         list_for_each_entry_rcu(found, head, list)
 363                 found->full = 0;
 364         rcu_read_unlock();
 365 }
 366
 367 static u64 div_factor(u64 num, int factor)
 368 {
 369         if (factor == 10)
 370                 return num;
 371         num *= factor;
 372         do_div(num, 10);
 373         return num;
 374 }
 375
 376 u64 btrfs_find_block_group(struct btrfs_root *root,
 377                            u64 search_start, u64 search_hint, int owner)
 378 {
 379         struct btrfs_block_group_cache *cache;
 380         u64 used;
 381         u64 last = max(search_hint, search_start);
 382         u64 group_start = 0;
 383         int full_search = 0;
 384         int factor = 9;
 385         int wrapped = 0;
 386 again:
 387         while (1) {
 388                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 389                 if (!cache)
 390                         break;
 391
 392                 spin_lock(&cache->lock);
 393                 last = cache->key.objectid + cache->key.offset;
 394                 used = btrfs_block_group_used(&cache->item);
 395
 396                 if ((full_search || !cache->ro) &&
 397                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 398                         if (used + cache->pinned + cache->reserved <
 399                             div_factor(cache->key.offset, factor)) {
 400                                 group_start = cache->key.objectid;
 401                                 spin_unlock(&cache->lock);
 402                                 put_block_group(cache);
 403                                 goto found;
 404                         }
 405                 }
 406                 spin_unlock(&cache->lock);
 407                 put_block_group(cache);
 408                 cond_resched();
 409         }
 410         if (!wrapped) {
 411                 last = search_start;
 412                 wrapped = 1;
 413                 goto again;
 414         }
 415         if (!full_search && factor < 10) {
 416                 last = search_start;
 417                 full_search = 1;
 418                 factor = 10;
 419                 goto again;
 420         }
 421 found:
 422         return group_start;
 423 }
 424
 425 /* simple helper to search for an existing extent at a given offset */
 426 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 427 {
 428         int ret;
 429         struct btrfs_key key;
 430         struct btrfs_path *path;
 431
 432         path = btrfs_alloc_path();
 433         BUG_ON(!path);
 434         key.objectid = start;
 435         key.offset = len;
 436         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 437         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 438                                 0, 0);
 439         btrfs_free_path(path);
 440         return ret;
 441 }
 442
 443 /*
 444  * Back reference rules.  Back refs have three main goals:
 445  *
 446  * 1) differentiate between all holders of references to an extent so that
 447  *    when a reference is dropped we can make sure it was a valid reference
 448  *    before freeing the extent.
 449  *
 450  * 2) Provide enough information to quickly find the holders of an extent
 451  *    if we notice a given block is corrupted or bad.
 452  *
 453  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 454  *    maintenance.  This is actually the same as #2, but with a slightly
 455  *    different use case.
 456  *
 457  * File extents can be referenced by:
 458  *
 459  * - multiple snapshots, subvolumes, or different generations in one subvol
 460  * - different files inside a single subvolume
 461  * - different offsets inside a file (bookend extents in file.c)
 462  *
 463  * The extent ref structure has fields for:
 464  *
 465  * - Objectid of the subvolume root
 466  * - Generation number of the tree holding the reference
 467  * - objectid of the file holding the reference
 468  * - number of references holding by parent node (alway 1 for tree blocks)
 469  *
 470  * Btree leaf may hold multiple references to a file extent. In most cases,
 471  * these references are from same file and the corresponding offsets inside
 472  * the file are close together.
 473  *
 474  * When a file extent is allocated the fields are filled in:
 475  *     (root_key.objectid, trans->transid, inode objectid, 1)
 476  *
 477  * When a leaf is cow'd new references are added for every file extent found
 478  * in the leaf.  It looks similar to the create case, but trans->transid will
 479  * be different when the block is cow'd.
 480  *
 481  *     (root_key.objectid, trans->transid, inode objectid,
 482  *      number of references in the leaf)
 483  *
 484  * When a file extent is removed either during snapshot deletion or
 485  * file truncation, we find the corresponding back reference and check
 486  * the following fields:
 487  *
 488  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 489  *      inode objectid)
 490  *
 491  * Btree extents can be referenced by:
 492  *
 493  * - Different subvolumes
 494  * - Different generations of the same subvolume
 495  *
 496  * When a tree block is created, back references are inserted:
 497  *
 498  * (root->root_key.objectid, trans->transid, level, 1)
 499  *
 500  * When a tree block is cow'd, new back references are added for all the
 501  * blocks it points to. If the tree block isn't in reference counted root,
 502  * the old back references are removed. These new back references are of
 503  * the form (trans->transid will have increased since creation):
 504  *
 505  * (root->root_key.objectid, trans->transid, level, 1)
 506  *
 507  * When a backref is in deleting, the following fields are checked:
 508  *
 509  * if backref was for a tree root:
 510  *     (btrfs_header_owner(itself), btrfs_header_generation(itself), level)
 511  * else
 512  *     (btrfs_header_owner(parent), btrfs_header_generation(parent), level)
 513  *
 514  * Back Reference Key composing:
 515  *
 516  * The key objectid corresponds to the first byte in the extent, the key
 517  * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
 518  * byte of parent extent. If a extent is tree root, the key offset is set
 519  * to the key objectid.
 520  */
 521
 522 static noinline int lookup_extent_backref(struct btrfs_trans_handle *trans,
 523                                           struct btrfs_root *root,
 524                                           struct btrfs_path *path,
 525                                           u64 bytenr, u64 parent,
 526                                           u64 ref_root, u64 ref_generation,
 527                                           u64 owner_objectid, int del)
 528 {
 529         struct btrfs_key key;
 530         struct btrfs_extent_ref *ref;
 531         struct extent_buffer *leaf;
 532         u64 ref_objectid;
 533         int ret;
 534
 535         key.objectid = bytenr;
 536         key.type = BTRFS_EXTENT_REF_KEY;
 537         key.offset = parent;
 538
 539         ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
 540         if (ret < 0)
 541                 goto out;
 542         if (ret > 0) {
 543                 ret = -ENOENT;
 544                 goto out;
 545         }
 546
 547         leaf = path->nodes[0];
 548         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 549         ref_objectid = btrfs_ref_objectid(leaf, ref);
 550         if (btrfs_ref_root(leaf, ref) != ref_root ||
 551             btrfs_ref_generation(leaf, ref) != ref_generation ||
 552             (ref_objectid != owner_objectid &&
 553              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 554                 ret = -EIO;
 555                 WARN_ON(1);
 556                 goto out;
 557         }
 558         ret = 0;
 559 out:
 560         return ret;
 561 }
 562
 563 static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 564                                           struct btrfs_root *root,
 565                                           struct btrfs_path *path,
 566                                           u64 bytenr, u64 parent,
 567                                           u64 ref_root, u64 ref_generation,
 568                                           u64 owner_objectid,
 569                                           int refs_to_add)
 570 {
 571         struct btrfs_key key;
 572         struct extent_buffer *leaf;
 573         struct btrfs_extent_ref *ref;
 574         u32 num_refs;
 575         int ret;
 576
 577         key.objectid = bytenr;
 578         key.type = BTRFS_EXTENT_REF_KEY;
 579         key.offset = parent;
 580
 581         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
 582         if (ret == 0) {
 583                 leaf = path->nodes[0];
 584                 ref = btrfs_item_ptr(leaf, path->slots[0],
 585                                      struct btrfs_extent_ref);
 586                 btrfs_set_ref_root(leaf, ref, ref_root);
 587                 btrfs_set_ref_generation(leaf, ref, ref_generation);
 588                 btrfs_set_ref_objectid(leaf, ref, owner_objectid);
 589                 btrfs_set_ref_num_refs(leaf, ref, refs_to_add);
 590         } else if (ret == -EEXIST) {
 591                 u64 existing_owner;
 592
 593                 BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
 594                 leaf = path->nodes[0];
 595                 ref = btrfs_item_ptr(leaf, path->slots[0],
 596                                      struct btrfs_extent_ref);
 597                 if (btrfs_ref_root(leaf, ref) != ref_root ||
 598                     btrfs_ref_generation(leaf, ref) != ref_generation) {
 599                         ret = -EIO;
 600                         WARN_ON(1);
 601                         goto out;
 602                 }
 603
 604                 num_refs = btrfs_ref_num_refs(leaf, ref);
 605                 BUG_ON(num_refs == 0);
 606                 btrfs_set_ref_num_refs(leaf, ref, num_refs + refs_to_add);
 607
 608                 existing_owner = btrfs_ref_objectid(leaf, ref);
 609                 if (existing_owner != owner_objectid &&
 610                     existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
 611                         btrfs_set_ref_objectid(leaf, ref,
 612                                         BTRFS_MULTIPLE_OBJECTIDS);
 613                 }
 614                 ret = 0;
 615         } else {
 616                 goto out;
 617         }
 618         btrfs_unlock_up_safe(path, 1);
 619         btrfs_mark_buffer_dirty(path->nodes[0]);
 620 out:
 621         btrfs_release_path(root, path);
 622         return ret;
 623 }
 624
 625 static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 626                                           struct btrfs_root *root,
 627                                           struct btrfs_path *path,
 628                                           int refs_to_drop)
 629 {
 630         struct extent_buffer *leaf;
 631         struct btrfs_extent_ref *ref;
 632         u32 num_refs;
 633         int ret = 0;
 634
 635         leaf = path->nodes[0];
 636         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 637         num_refs = btrfs_ref_num_refs(leaf, ref);
 638         BUG_ON(num_refs < refs_to_drop);
 639         num_refs -= refs_to_drop;
 640         if (num_refs == 0) {
 641                 ret = btrfs_del_item(trans, root, path);
 642         } else {
 643                 btrfs_set_ref_num_refs(leaf, ref, num_refs);
 644                 btrfs_mark_buffer_dirty(leaf);
 645         }
 646         btrfs_release_path(root, path);
 647         return ret;
 648 }
 649
 650 #ifdef BIO_RW_DISCARD
 651 static void btrfs_issue_discard(struct block_device *bdev,
 652                                 u64 start, u64 len)
 653 {
 654         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
 655 }
 656 #endif
 657
 658 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 659                                 u64 num_bytes)
 660 {
 661 #ifdef BIO_RW_DISCARD
 662         int ret;
 663         u64 map_length = num_bytes;
 664         struct btrfs_multi_bio *multi = NULL;
 665
 666         /* Tell the block device(s) that the sectors can be discarded */
 667         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
 668                               bytenr, &map_length, &multi, 0);
 669         if (!ret) {
 670                 struct btrfs_bio_stripe *stripe = multi->stripes;
 671                 int i;
 672
 673                 if (map_length > num_bytes)
 674                         map_length = num_bytes;
 675
 676                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
 677                         btrfs_issue_discard(stripe->dev->bdev,
 678                                             stripe->physical,
 679                                             map_length);
 680                 }
 681                 kfree(multi);
 682         }
 683
 684         return ret;
 685 #else
 686         return 0;
 687 #endif
 688 }
 689
 690 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 691                                      struct btrfs_root *root, u64 bytenr,
 692                                      u64 num_bytes,
 693                                      u64 orig_parent, u64 parent,
 694                                      u64 orig_root, u64 ref_root,
 695                                      u64 orig_generation, u64 ref_generation,
 696                                      u64 owner_objectid)
 697 {
 698         int ret;
 699         int pin = owner_objectid < BTRFS_FIRST_FREE_OBJECTID;
 700
 701         ret = btrfs_update_delayed_ref(trans, bytenr, num_bytes,
 702                                        orig_parent, parent, orig_root,
 703                                        ref_root, orig_generation,
 704                                        ref_generation, owner_objectid, pin);
 705         BUG_ON(ret);
 706         return ret;
 707 }
 708
 709 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 710                             struct btrfs_root *root, u64 bytenr,
 711                             u64 num_bytes, u64 orig_parent, u64 parent,
 712                             u64 ref_root, u64 ref_generation,
 713                             u64 owner_objectid)
 714 {
 715         int ret;
 716         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 717             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 718                 return 0;
 719
 720         ret = __btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
 721                                         orig_parent, parent, ref_root,
 722                                         ref_root, ref_generation,
 723                                         ref_generation, owner_objectid);
 724         return ret;
 725 }
 726 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 727                                   struct btrfs_root *root, u64 bytenr,
 728                                   u64 num_bytes,
 729                                   u64 orig_parent, u64 parent,
 730                                   u64 orig_root, u64 ref_root,
 731                                   u64 orig_generation, u64 ref_generation,
 732                                   u64 owner_objectid)
 733 {
 734         int ret;
 735
 736         ret = btrfs_add_delayed_ref(trans, bytenr, num_bytes, parent, ref_root,
 737                                     ref_generation, owner_objectid,
 738                                     BTRFS_ADD_DELAYED_REF, 0);
 739         BUG_ON(ret);
 740         return ret;
 741 }
 742
 743 static noinline_for_stack int add_extent_ref(struct btrfs_trans_handle *trans,
 744                           struct btrfs_root *root, u64 bytenr,
 745                           u64 num_bytes, u64 parent, u64 ref_root,
 746                           u64 ref_generation, u64 owner_objectid,
 747                           int refs_to_add)
 748 {
 749         struct btrfs_path *path;
 750         int ret;
 751         struct btrfs_key key;
 752         struct extent_buffer *l;
 753         struct btrfs_extent_item *item;
 754         u32 refs;
 755
 756         path = btrfs_alloc_path();
 757         if (!path)
 758                 return -ENOMEM;
 759
 760         path->reada = 1;
 761         path->leave_spinning = 1;
 762         key.objectid = bytenr;
 763         key.type = BTRFS_EXTENT_ITEM_KEY;
 764         key.offset = num_bytes;
 765
 766         /* first find the extent item and update its reference count */
 767         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
 768                                 path, 0, 1);
 769         if (ret < 0) {
 770                 btrfs_set_path_blocking(path);
 771                 return ret;
 772         }
 773
 774         if (ret > 0) {
 775                 WARN_ON(1);
 776                 btrfs_free_path(path);
 777                 return -EIO;
 778         }
 779         l = path->nodes[0];
 780
 781         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 782         if (key.objectid != bytenr) {
 783                 btrfs_print_leaf(root->fs_info->extent_root, path->nodes[0]);
 784                 printk(KERN_ERR "btrfs wanted %llu found %llu\n",
 785                        (unsigned long long)bytenr,
 786                        (unsigned long long)key.objectid);
 787                 BUG();
 788         }
 789         BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
 790
 791         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 792
 793         refs = btrfs_extent_refs(l, item);
 794         btrfs_set_extent_refs(l, item, refs + refs_to_add);
 795         btrfs_unlock_up_safe(path, 1);
 796
 797         btrfs_mark_buffer_dirty(path->nodes[0]);
 798
 799         btrfs_release_path(root->fs_info->extent_root, path);
 800
 801         path->reada = 1;
 802         path->leave_spinning = 1;
 803
 804         /* now insert the actual backref */
 805         ret = insert_extent_backref(trans, root->fs_info->extent_root,
 806                                     path, bytenr, parent,
 807                                     ref_root, ref_generation,
 808                                     owner_objectid, refs_to_add);
 809         BUG_ON(ret);
 810         btrfs_free_path(path);
 811         return 0;
 812 }
 813
 814 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 815                          struct btrfs_root *root,
 816                          u64 bytenr, u64 num_bytes, u64 parent,
 817                          u64 ref_root, u64 ref_generation,
 818                          u64 owner_objectid)
 819 {
 820         int ret;
 821         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 822             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 823                 return 0;
 824
 825         ret = __btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, parent,
 826                                      0, ref_root, 0, ref_generation,
 827                                      owner_objectid);
 828         return ret;
 829 }
 830
 831 static int drop_delayed_ref(struct btrfs_trans_handle *trans,
 832                                         struct btrfs_root *root,
 833                                         struct btrfs_delayed_ref_node *node)
 834 {
 835         int ret = 0;
 836         struct btrfs_delayed_ref *ref = btrfs_delayed_node_to_ref(node);
 837
 838         BUG_ON(node->ref_mod == 0);
 839         ret = __btrfs_free_extent(trans, root, node->bytenr, node->num_bytes,
 840                                   node->parent, ref->root, ref->generation,
 841                                   ref->owner_objectid, ref->pin, node->ref_mod);
 842
 843         return ret;
 844 }
 845
 846 /* helper function to actually process a single delayed ref entry */
 847 static noinline int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 848                                         struct btrfs_root *root,
 849                                         struct btrfs_delayed_ref_node *node,
 850                                         int insert_reserved)
 851 {
 852         int ret;
 853         struct btrfs_delayed_ref *ref;
 854
 855         if (node->parent == (u64)-1) {
 856                 struct btrfs_delayed_ref_head *head;
 857                 /*
 858                  * we've hit the end of the chain and we were supposed
 859                  * to insert this extent into the tree.  But, it got
 860                  * deleted before we ever needed to insert it, so all
 861                  * we have to do is clean up the accounting
 862                  */
 863                 if (insert_reserved) {
 864                         update_reserved_extents(root, node->bytenr,
 865                                                 node->num_bytes, 0);
 866                 }
 867                 head = btrfs_delayed_node_to_head(node);
 868                 mutex_unlock(&head->mutex);
 869                 return 0;
 870         }
 871
 872         ref = btrfs_delayed_node_to_ref(node);
 873         if (ref->action == BTRFS_ADD_DELAYED_REF) {
 874                 if (insert_reserved) {
 875                         struct btrfs_key ins;
 876
 877                         ins.objectid = node->bytenr;
 878                         ins.offset = node->num_bytes;
 879                         ins.type = BTRFS_EXTENT_ITEM_KEY;
 880
 881                         /* record the full extent allocation */
 882                         ret = __btrfs_alloc_reserved_extent(trans, root,
 883                                         node->parent, ref->root,
 884                                         ref->generation, ref->owner_objectid,
 885                                         &ins, node->ref_mod);
 886                         update_reserved_extents(root, node->bytenr,
 887                                                 node->num_bytes, 0);
 888                 } else {
 889                         /* just add one backref */
 890                         ret = add_extent_ref(trans, root, node->bytenr,
 891                                      node->num_bytes,
 892                                      node->parent, ref->root, ref->generation,
 893                                      ref->owner_objectid, node->ref_mod);
 894                 }
 895                 BUG_ON(ret);
 896         } else if (ref->action == BTRFS_DROP_DELAYED_REF) {
 897                 WARN_ON(insert_reserved);
 898                 ret = drop_delayed_ref(trans, root, node);
 899         }
 900         return 0;
 901 }
 902
 903 static noinline struct btrfs_delayed_ref_node *
 904 select_delayed_ref(struct btrfs_delayed_ref_head *head)
 905 {
 906         struct rb_node *node;
 907         struct btrfs_delayed_ref_node *ref;
 908         int action = BTRFS_ADD_DELAYED_REF;
 909 again:
 910         /*
 911          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
 912          * this prevents ref count from going down to zero when
 913          * there still are pending delayed ref.
 914          */
 915         node = rb_prev(&head->node.rb_node);
 916         while (1) {
 917                 if (!node)
 918                         break;
 919                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
 920                                 rb_node);
 921                 if (ref->bytenr != head->node.bytenr)
 922                         break;
 923                 if (btrfs_delayed_node_to_ref(ref)->action == action)
 924                         return ref;
 925                 node = rb_prev(node);
 926         }
 927         if (action == BTRFS_ADD_DELAYED_REF) {
 928                 action = BTRFS_DROP_DELAYED_REF;
 929                 goto again;
 930         }
 931         return NULL;
 932 }
 933
 934 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
 935                                        struct btrfs_root *root,
 936                                        struct list_head *cluster)
 937 {
 938         struct btrfs_delayed_ref_root *delayed_refs;
 939         struct btrfs_delayed_ref_node *ref;
 940         struct btrfs_delayed_ref_head *locked_ref = NULL;
 941         int ret;
 942         int count = 0;
 943         int must_insert_reserved = 0;
 944
 945         delayed_refs = &trans->transaction->delayed_refs;
 946         while (1) {
 947                 if (!locked_ref) {
 948                         /* pick a new head ref from the cluster list */
 949                         if (list_empty(cluster))
 950                                 break;
 951
 952                         locked_ref = list_entry(cluster->next,
 953                                      struct btrfs_delayed_ref_head, cluster);
 954
 955                         /* grab the lock that says we are going to process
 956                          * all the refs for this head */
 957                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
 958
 959                         /*
 960                          * we may have dropped the spin lock to get the head
 961                          * mutex lock, and that might have given someone else
 962                          * time to free the head.  If that's true, it has been
 963                          * removed from our list and we can move on.
 964                          */
 965                         if (ret == -EAGAIN) {
 966                                 locked_ref = NULL;
 967                                 count++;
 968                                 continue;
 969                         }
 970                 }
 971
 972                 /*
 973                  * record the must insert reserved flag before we
 974                  * drop the spin lock.
 975                  */
 976                 must_insert_reserved = locked_ref->must_insert_reserved;
 977                 locked_ref->must_insert_reserved = 0;
 978
 979                 /*
 980                  * locked_ref is the head node, so we have to go one
 981                  * node back for any delayed ref updates
 982                  */
 983                 ref = select_delayed_ref(locked_ref);
 984                 if (!ref) {
 985                         /* All delayed refs have been processed, Go ahead
 986                          * and send the head node to run_one_delayed_ref,
 987                          * so that any accounting fixes can happen
 988                          */
 989                         ref = &locked_ref->node;
 990                         list_del_init(&locked_ref->cluster);
 991                         locked_ref = NULL;
 992                 }
 993
 994                 ref->in_tree = 0;
 995                 rb_erase(&ref->rb_node, &delayed_refs->root);
 996                 delayed_refs->num_entries--;
 997                 spin_unlock(&delayed_refs->lock);
 998
 999                 ret = run_one_delayed_ref(trans, root, ref,
1000                                           must_insert_reserved);
1001                 BUG_ON(ret);
1002                 btrfs_put_delayed_ref(ref);
1003
1004                 count++;
1005                 cond_resched();
1006                 spin_lock(&delayed_refs->lock);
1007         }
1008         return count;
1009 }
1010
1011 /*
1012  * this starts processing the delayed reference count updates and
1013  * extent insertions we have queued up so far.  count can be
1014  * 0, which means to process everything in the tree at the start
1015  * of the run (but not newly added entries), or it can be some target
1016  * number you'd like to process.
1017  */
1018 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
1019                            struct btrfs_root *root, unsigned long count)
1020 {
1021         struct rb_node *node;
1022         struct btrfs_delayed_ref_root *delayed_refs;
1023         struct btrfs_delayed_ref_node *ref;
1024         struct list_head cluster;
1025         int ret;
1026         int run_all = count == (unsigned long)-1;
1027         int run_most = 0;
1028
1029         if (root == root->fs_info->extent_root)
1030                 root = root->fs_info->tree_root;
1031
1032         delayed_refs = &trans->transaction->delayed_refs;
1033         INIT_LIST_HEAD(&cluster);
1034 again:
1035         spin_lock(&delayed_refs->lock);
1036         if (count == 0) {
1037                 count = delayed_refs->num_entries * 2;
1038                 run_most = 1;
1039         }
1040         while (1) {
1041                 if (!(run_all || run_most) &&
1042                     delayed_refs->num_heads_ready < 64)
1043                         break;
1044
1045                 /*
1046                  * go find something we can process in the rbtree.  We start at
1047                  * the beginning of the tree, and then build a cluster
1048                  * of refs to process starting at the first one we are able to
1049                  * lock
1050                  */
1051                 ret = btrfs_find_ref_cluster(trans, &cluster,
1052                                              delayed_refs->run_delayed_start);
1053                 if (ret)
1054                         break;
1055
1056                 ret = run_clustered_refs(trans, root, &cluster);
1057                 BUG_ON(ret < 0);
1058
1059                 count -= min_t(unsigned long, ret, count);
1060
1061                 if (count == 0)
1062                         break;
1063         }
1064
1065         if (run_all) {
1066                 node = rb_first(&delayed_refs->root);
1067                 if (!node)
1068                         goto out;
1069                 count = (unsigned long)-1;
1070
1071                 while (node) {
1072                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
1073                                        rb_node);
1074                         if (btrfs_delayed_ref_is_head(ref)) {
1075                                 struct btrfs_delayed_ref_head *head;
1076
1077                                 head = btrfs_delayed_node_to_head(ref);
1078                                 atomic_inc(&ref->refs);
1079
1080                                 spin_unlock(&delayed_refs->lock);
1081                                 mutex_lock(&head->mutex);
1082                                 mutex_unlock(&head->mutex);
1083
1084                                 btrfs_put_delayed_ref(ref);
1085                                 cond_resched();
1086                                 goto again;
1087                         }
1088                         node = rb_next(node);
1089                 }
1090                 spin_unlock(&delayed_refs->lock);
1091                 schedule_timeout(1);
1092                 goto again;
1093         }
1094 out:
1095         spin_unlock(&delayed_refs->lock);
1096         return 0;
1097 }
1098
1099 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
1100                           struct btrfs_root *root, u64 objectid, u64 bytenr)
1101 {
1102         struct btrfs_root *extent_root = root->fs_info->extent_root;
1103         struct btrfs_path *path;
1104         struct extent_buffer *leaf;
1105         struct btrfs_extent_ref *ref_item;
1106         struct btrfs_key key;
1107         struct btrfs_key found_key;
1108         u64 ref_root;
1109         u64 last_snapshot;
1110         u32 nritems;
1111         int ret;
1112
1113         key.objectid = bytenr;
1114         key.offset = (u64)-1;
1115         key.type = BTRFS_EXTENT_ITEM_KEY;
1116
1117         path = btrfs_alloc_path();
1118         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
1119         if (ret < 0)
1120                 goto out;
1121         BUG_ON(ret == 0);
1122
1123         ret = -ENOENT;
1124         if (path->slots[0] == 0)
1125                 goto out;
1126
1127         path->slots[0]--;
1128         leaf = path->nodes[0];
1129         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1130
1131         if (found_key.objectid != bytenr ||
1132             found_key.type != BTRFS_EXTENT_ITEM_KEY)
1133                 goto out;
1134
1135         last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1136         while (1) {
1137                 leaf = path->nodes[0];
1138                 nritems = btrfs_header_nritems(leaf);
1139                 if (path->slots[0] >= nritems) {
1140                         ret = btrfs_next_leaf(extent_root, path);
1141                         if (ret < 0)
1142                                 goto out;
1143                         if (ret == 0)
1144                                 continue;
1145                         break;
1146                 }
1147                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1148                 if (found_key.objectid != bytenr)
1149                         break;
1150
1151                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
1152                         path->slots[0]++;
1153                         continue;
1154                 }
1155
1156                 ref_item = btrfs_item_ptr(leaf, path->slots[0],
1157                                           struct btrfs_extent_ref);
1158                 ref_root = btrfs_ref_root(leaf, ref_item);
1159                 if ((ref_root != root->root_key.objectid &&
1160                      ref_root != BTRFS_TREE_LOG_OBJECTID) ||
1161                      objectid != btrfs_ref_objectid(leaf, ref_item)) {
1162                         ret = 1;
1163                         goto out;
1164                 }
1165                 if (btrfs_ref_generation(leaf, ref_item) <= last_snapshot) {
1166                         ret = 1;
1167                         goto out;
1168                 }
1169
1170                 path->slots[0]++;
1171         }
1172         ret = 0;
1173 out:
1174         btrfs_free_path(path);
1175         return ret;
1176 }
1177
1178 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1179                     struct extent_buffer *buf, u32 nr_extents)
1180 {
1181         struct btrfs_key key;
1182         struct btrfs_file_extent_item *fi;
1183         u64 root_gen;
1184         u32 nritems;
1185         int i;
1186         int level;
1187         int ret = 0;
1188         int shared = 0;
1189
1190         if (!root->ref_cows)
1191                 return 0;
1192
1193         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1194                 shared = 0;
1195                 root_gen = root->root_key.offset;
1196         } else {
1197                 shared = 1;
1198                 root_gen = trans->transid - 1;
1199         }
1200
1201         level = btrfs_header_level(buf);
1202         nritems = btrfs_header_nritems(buf);
1203
1204         if (level == 0) {
1205                 struct btrfs_leaf_ref *ref;
1206                 struct btrfs_extent_info *info;
1207
1208                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
1209                 if (!ref) {
1210                         ret = -ENOMEM;
1211                         goto out;
1212                 }
1213
1214                 ref->root_gen = root_gen;
1215                 ref->bytenr = buf->start;
1216                 ref->owner = btrfs_header_owner(buf);
1217                 ref->generation = btrfs_header_generation(buf);
1218                 ref->nritems = nr_extents;
1219                 info = ref->extents;
1220
1221                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
1222                         u64 disk_bytenr;
1223                         btrfs_item_key_to_cpu(buf, &key, i);
1224                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1225                                 continue;
1226                         fi = btrfs_item_ptr(buf, i,
1227                                             struct btrfs_file_extent_item);
1228                         if (btrfs_file_extent_type(buf, fi) ==
1229                             BTRFS_FILE_EXTENT_INLINE)
1230                                 continue;
1231                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1232                         if (disk_bytenr == 0)
1233                                 continue;
1234
1235                         info->bytenr = disk_bytenr;
1236                         info->num_bytes =
1237                                 btrfs_file_extent_disk_num_bytes(buf, fi);
1238                         info->objectid = key.objectid;
1239                         info->offset = key.offset;
1240                         info++;
1241                 }
1242
1243                 ret = btrfs_add_leaf_ref(root, ref, shared);
1244                 if (ret == -EEXIST && shared) {
1245                         struct btrfs_leaf_ref *old;
1246                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
1247                         BUG_ON(!old);
1248                         btrfs_remove_leaf_ref(root, old);
1249                         btrfs_free_leaf_ref(root, old);
1250                         ret = btrfs_add_leaf_ref(root, ref, shared);
1251                 }
1252                 WARN_ON(ret);
1253                 btrfs_free_leaf_ref(root, ref);
1254         }
1255 out:
1256         return ret;
1257 }
1258
1259 /* when a block goes through cow, we update the reference counts of
1260  * everything that block points to.  The internal pointers of the block
1261  * can be in just about any order, and it is likely to have clusters of
1262  * things that are close together and clusters of things that are not.
1263  *
1264  * To help reduce the seeks that come with updating all of these reference
1265  * counts, sort them by byte number before actual updates are done.
1266  *
1267  * struct refsort is used to match byte number to slot in the btree block.
1268  * we sort based on the byte number and then use the slot to actually
1269  * find the item.
1270  *
1271  * struct refsort is smaller than strcut btrfs_item and smaller than
1272  * struct btrfs_key_ptr.  Since we're currently limited to the page size
1273  * for a btree block, there's no way for a kmalloc of refsorts for a
1274  * single node to be bigger than a page.
1275  */
1276 struct refsort {
1277         u64 bytenr;
1278         u32 slot;
1279 };
1280
1281 /*
1282  * for passing into sort()
1283  */
1284 static int refsort_cmp(const void *a_void, const void *b_void)
1285 {
1286         const struct refsort *a = a_void;
1287         const struct refsort *b = b_void;
1288
1289         if (a->bytenr < b->bytenr)
1290                 return -1;
1291         if (a->bytenr > b->bytenr)
1292                 return 1;
1293         return 0;
1294 }
1295
1296
1297 noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans,
1298                            struct btrfs_root *root,
1299                            struct extent_buffer *orig_buf,
1300                            struct extent_buffer *buf, u32 *nr_extents)
1301 {
1302         u64 bytenr;
1303         u64 ref_root;
1304         u64 orig_root;
1305         u64 ref_generation;
1306         u64 orig_generation;
1307         struct refsort *sorted;
1308         u32 nritems;
1309         u32 nr_file_extents = 0;
1310         struct btrfs_key key;
1311         struct btrfs_file_extent_item *fi;
1312         int i;
1313         int level;
1314         int ret = 0;
1315         int faili = 0;
1316         int refi = 0;
1317         int slot;
1318         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
1319                             u64, u64, u64, u64, u64, u64, u64, u64, u64);
1320
1321         ref_root = btrfs_header_owner(buf);
1322         ref_generation = btrfs_header_generation(buf);
1323         orig_root = btrfs_header_owner(orig_buf);
1324         orig_generation = btrfs_header_generation(orig_buf);
1325
1326         nritems = btrfs_header_nritems(buf);
1327         level = btrfs_header_level(buf);
1328
1329         sorted = kmalloc(sizeof(struct refsort) * nritems, GFP_NOFS);
1330         BUG_ON(!sorted);
1331
1332         if (root->ref_cows) {
1333                 process_func = __btrfs_inc_extent_ref;
1334         } else {
1335                 if (level == 0 &&
1336                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1337                         goto out;
1338                 if (level != 0 &&
1339                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1340                         goto out;
1341                 process_func = __btrfs_update_extent_ref;
1342         }
1343
1344         /*
1345          * we make two passes through the items.  In the first pass we
1346          * only record the byte number and slot.  Then we sort based on
1347          * byte number and do the actual work based on the sorted results
1348          */
1349         for (i = 0; i < nritems; i++) {
1350                 cond_resched();
1351                 if (level == 0) {
1352                         btrfs_item_key_to_cpu(buf, &key, i);
1353                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1354                                 continue;
1355                         fi = btrfs_item_ptr(buf, i,
1356                                             struct btrfs_file_extent_item);
1357                         if (btrfs_file_extent_type(buf, fi) ==
1358                             BTRFS_FILE_EXTENT_INLINE)
1359                                 continue;
1360                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1361                         if (bytenr == 0)
1362                                 continue;
1363
1364                         nr_file_extents++;
1365                         sorted[refi].bytenr = bytenr;
1366                         sorted[refi].slot = i;
1367                         refi++;
1368                 } else {
1369                         bytenr = btrfs_node_blockptr(buf, i);
1370                         sorted[refi].bytenr = bytenr;
1371                         sorted[refi].slot = i;
1372                         refi++;
1373                 }
1374         }
1375         /*
1376          * if refi == 0, we didn't actually put anything into the sorted
1377          * array and we're done
1378          */
1379         if (refi == 0)
1380                 goto out;
1381
1382         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
1383
1384         for (i = 0; i < refi; i++) {
1385                 cond_resched();
1386                 slot = sorted[i].slot;
1387                 bytenr = sorted[i].bytenr;
1388
1389                 if (level == 0) {
1390                         btrfs_item_key_to_cpu(buf, &key, slot);
1391                         fi = btrfs_item_ptr(buf, slot,
1392                                             struct btrfs_file_extent_item);
1393
1394                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1395                         if (bytenr == 0)
1396                                 continue;
1397
1398                         ret = process_func(trans, root, bytenr,
1399                                    btrfs_file_extent_disk_num_bytes(buf, fi),
1400                                    orig_buf->start, buf->start,
1401                                    orig_root, ref_root,
1402                                    orig_generation, ref_generation,
1403                                    key.objectid);
1404
1405                         if (ret) {
1406                                 faili = slot;
1407                                 WARN_ON(1);
1408                                 goto fail;
1409                         }
1410                 } else {
1411                         ret = process_func(trans, root, bytenr, buf->len,
1412                                            orig_buf->start, buf->start,
1413                                            orig_root, ref_root,
1414                                            orig_generation, ref_generation,
1415                                            level - 1);
1416                         if (ret) {
1417                                 faili = slot;
1418                                 WARN_ON(1);
1419                                 goto fail;
1420                         }
1421                 }
1422         }
1423 out:
1424         kfree(sorted);
1425         if (nr_extents) {
1426                 if (level == 0)
1427                         *nr_extents = nr_file_extents;
1428                 else
1429                         *nr_extents = nritems;
1430         }
1431         return 0;
1432 fail:
1433         kfree(sorted);
1434         WARN_ON(1);
1435         return ret;
1436 }
1437
1438 int btrfs_update_ref(struct btrfs_trans_handle *trans,
1439                      struct btrfs_root *root, struct extent_buffer *orig_buf,
1440                      struct extent_buffer *buf, int start_slot, int nr)
1441
1442 {
1443         u64 bytenr;
1444         u64 ref_root;
1445         u64 orig_root;
1446         u64 ref_generation;
1447         u64 orig_generation;
1448         struct btrfs_key key;
1449         struct btrfs_file_extent_item *fi;
1450         int i;
1451         int ret;
1452         int slot;
1453         int level;
1454
1455         BUG_ON(start_slot < 0);
1456         BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
1457
1458         ref_root = btrfs_header_owner(buf);
1459         ref_generation = btrfs_header_generation(buf);
1460         orig_root = btrfs_header_owner(orig_buf);
1461         orig_generation = btrfs_header_generation(orig_buf);
1462         level = btrfs_header_level(buf);
1463
1464         if (!root->ref_cows) {
1465                 if (level == 0 &&
1466                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1467                         return 0;
1468                 if (level != 0 &&
1469                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1470                         return 0;
1471         }
1472
1473         for (i = 0, slot = start_slot; i < nr; i++, slot++) {
1474                 cond_resched();
1475                 if (level == 0) {
1476                         btrfs_item_key_to_cpu(buf, &key, slot);
1477                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1478                                 continue;
1479                         fi = btrfs_item_ptr(buf, slot,
1480                                             struct btrfs_file_extent_item);
1481                         if (btrfs_file_extent_type(buf, fi) ==
1482                             BTRFS_FILE_EXTENT_INLINE)
1483                                 continue;
1484                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1485                         if (bytenr == 0)
1486                                 continue;
1487                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1488                                     btrfs_file_extent_disk_num_bytes(buf, fi),
1489                                     orig_buf->start, buf->start,
1490                                     orig_root, ref_root, orig_generation,
1491                                     ref_generation, key.objectid);
1492                         if (ret)
1493                                 goto fail;
1494                 } else {
1495                         bytenr = btrfs_node_blockptr(buf, slot);
1496                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1497                                             buf->len, orig_buf->start,
1498                                             buf->start, orig_root, ref_root,
1499                                             orig_generation, ref_generation,
1500                                             level - 1);
1501                         if (ret)
1502                                 goto fail;
1503                 }
1504         }
1505         return 0;
1506 fail:
1507         WARN_ON(1);
1508         return -1;
1509 }
1510
1511 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1512                                  struct btrfs_root *root,
1513                                  struct btrfs_path *path,
1514                                  struct btrfs_block_group_cache *cache)
1515 {
1516         int ret;
1517         struct btrfs_root *extent_root = root->fs_info->extent_root;
1518         unsigned long bi;
1519         struct extent_buffer *leaf;
1520
1521         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1522         if (ret < 0)
1523                 goto fail;
1524         BUG_ON(ret);
1525
1526         leaf = path->nodes[0];
1527         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1528         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1529         btrfs_mark_buffer_dirty(leaf);
1530         btrfs_release_path(extent_root, path);
1531 fail:
1532         if (ret)
1533                 return ret;
1534         return 0;
1535
1536 }
1537
1538 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1539                                    struct btrfs_root *root)
1540 {
1541         struct btrfs_block_group_cache *cache, *entry;
1542         struct rb_node *n;
1543         int err = 0;
1544         int werr = 0;
1545         struct btrfs_path *path;
1546         u64 last = 0;
1547
1548         path = btrfs_alloc_path();
1549         if (!path)
1550                 return -ENOMEM;
1551
1552         while (1) {
1553                 cache = NULL;
1554                 spin_lock(&root->fs_info->block_group_cache_lock);
1555                 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1556                      n; n = rb_next(n)) {
1557                         entry = rb_entry(n, struct btrfs_block_group_cache,
1558                                          cache_node);
1559                         if (entry->dirty) {
1560                                 cache = entry;
1561                                 break;
1562                         }
1563                 }
1564                 spin_unlock(&root->fs_info->block_group_cache_lock);
1565
1566                 if (!cache)
1567                         break;
1568
1569                 cache->dirty = 0;
1570                 last += cache->key.offset;
1571
1572                 err = write_one_cache_group(trans, root,
1573                                             path, cache);
1574                 /*
1575                  * if we fail to write the cache group, we want
1576                  * to keep it marked dirty in hopes that a later
1577                  * write will work
1578                  */
1579                 if (err) {
1580                         werr = err;
1581                         continue;
1582                 }
1583         }
1584         btrfs_free_path(path);
1585         return werr;
1586 }
1587
1588 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
1589 {
1590         struct btrfs_block_group_cache *block_group;
1591         int readonly = 0;
1592
1593         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
1594         if (!block_group || block_group->ro)
1595                 readonly = 1;
1596         if (block_group)
1597                 put_block_group(block_group);
1598         return readonly;
1599 }
1600
1601 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1602                              u64 total_bytes, u64 bytes_used,
1603                              struct btrfs_space_info **space_info)
1604 {
1605         struct btrfs_space_info *found;
1606
1607         found = __find_space_info(info, flags);
1608         if (found) {
1609                 spin_lock(&found->lock);
1610                 found->total_bytes += total_bytes;
1611                 found->bytes_used += bytes_used;
1612                 found->full = 0;
1613                 spin_unlock(&found->lock);
1614                 *space_info = found;
1615                 return 0;
1616         }
1617         found = kzalloc(sizeof(*found), GFP_NOFS);
1618         if (!found)
1619                 return -ENOMEM;
1620
1621         INIT_LIST_HEAD(&found->block_groups);
1622         init_rwsem(&found->groups_sem);
1623         spin_lock_init(&found->lock);
1624         found->flags = flags;
1625         found->total_bytes = total_bytes;
1626         found->bytes_used = bytes_used;
1627         found->bytes_pinned = 0;
1628         found->bytes_reserved = 0;
1629         found->bytes_readonly = 0;
1630         found->bytes_delalloc = 0;
1631         found->full = 0;
1632         found->force_alloc = 0;
1633         *space_info = found;
1634         list_add_rcu(&found->list, &info->space_info);
1635         return 0;
1636 }
1637
1638 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1639 {
1640         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1641                                    BTRFS_BLOCK_GROUP_RAID1 |
1642                                    BTRFS_BLOCK_GROUP_RAID10 |
1643                                    BTRFS_BLOCK_GROUP_DUP);
1644         if (extra_flags) {
1645                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1646                         fs_info->avail_data_alloc_bits |= extra_flags;
1647                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1648                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1649                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1650                         fs_info->avail_system_alloc_bits |= extra_flags;
1651         }
1652 }
1653
1654 static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
1655 {
1656         spin_lock(&cache->space_info->lock);
1657         spin_lock(&cache->lock);
1658         if (!cache->ro) {
1659                 cache->space_info->bytes_readonly += cache->key.offset -
1660                                         btrfs_block_group_used(&cache->item);
1661                 cache->ro = 1;
1662         }
1663         spin_unlock(&cache->lock);
1664         spin_unlock(&cache->space_info->lock);
1665 }
1666
1667 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1668 {
1669         u64 num_devices = root->fs_info->fs_devices->rw_devices;
1670
1671         if (num_devices == 1)
1672                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1673         if (num_devices < 4)
1674                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1675
1676         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1677             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1678                       BTRFS_BLOCK_GROUP_RAID10))) {
1679                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1680         }
1681
1682         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1683             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1684                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1685         }
1686
1687         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1688             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1689              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1690              (flags & BTRFS_BLOCK_GROUP_DUP)))
1691                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1692         return flags;
1693 }
1694
1695 static u64 btrfs_get_alloc_profile(struct btrfs_root *root, u64 data)
1696 {
1697         struct btrfs_fs_info *info = root->fs_info;
1698         u64 alloc_profile;
1699
1700         if (data) {
1701                 alloc_profile = info->avail_data_alloc_bits &
1702                         info->data_alloc_profile;
1703                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1704         } else if (root == root->fs_info->chunk_root) {
1705                 alloc_profile = info->avail_system_alloc_bits &
1706                         info->system_alloc_profile;
1707                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1708         } else {
1709                 alloc_profile = info->avail_metadata_alloc_bits &
1710                         info->metadata_alloc_profile;
1711                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1712         }
1713
1714         return btrfs_reduce_alloc_profile(root, data);
1715 }
1716
1717 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
1718 {
1719         u64 alloc_target;
1720
1721         alloc_target = btrfs_get_alloc_profile(root, 1);
1722         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
1723                                                        alloc_target);
1724 }
1725
1726 /*
1727  * for now this just makes sure we have at least 5% of our metadata space free
1728  * for use.
1729  */
1730 int btrfs_check_metadata_free_space(struct btrfs_root *root)
1731 {
1732         struct btrfs_fs_info *info = root->fs_info;
1733         struct btrfs_space_info *meta_sinfo;
1734         u64 alloc_target, thresh;
1735         int committed = 0, ret;
1736
1737         /* get the space info for where the metadata will live */
1738         alloc_target = btrfs_get_alloc_profile(root, 0);
1739         meta_sinfo = __find_space_info(info, alloc_target);
1740
1741 again:
1742         spin_lock(&meta_sinfo->lock);
1743         if (!meta_sinfo->full)
1744                 thresh = meta_sinfo->total_bytes * 80;
1745         else
1746                 thresh = meta_sinfo->total_bytes * 95;
1747
1748         do_div(thresh, 100);
1749
1750         if (meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
1751             meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly > thresh) {
1752                 struct btrfs_trans_handle *trans;
1753                 if (!meta_sinfo->full) {
1754                         meta_sinfo->force_alloc = 1;
1755                         spin_unlock(&meta_sinfo->lock);
1756
1757                         trans = btrfs_start_transaction(root, 1);
1758                         if (!trans)
1759                                 return -ENOMEM;
1760
1761                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1762                                              2 * 1024 * 1024, alloc_target, 0);
1763                         btrfs_end_transaction(trans, root);
1764                         goto again;
1765                 }
1766                 spin_unlock(&meta_sinfo->lock);
1767
1768                 if (!committed) {
1769                         committed = 1;
1770                         trans = btrfs_join_transaction(root, 1);
1771                         if (!trans)
1772                                 return -ENOMEM;
1773                         ret = btrfs_commit_transaction(trans, root);
1774                         if (ret)
1775                                 return ret;
1776                         goto again;
1777                 }
1778                 return -ENOSPC;
1779         }
1780         spin_unlock(&meta_sinfo->lock);
1781
1782         return 0;
1783 }
1784
1785 /*
1786  * This will check the space that the inode allocates from to make sure we have
1787  * enough space for bytes.
1788  */
1789 int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
1790                                 u64 bytes)
1791 {
1792         struct btrfs_space_info *data_sinfo;
1793         int ret = 0, committed = 0;
1794
1795         /* make sure bytes are sectorsize aligned */
1796         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
1797
1798         data_sinfo = BTRFS_I(inode)->space_info;
1799 again:
1800         /* make sure we have enough space to handle the data first */
1801         spin_lock(&data_sinfo->lock);
1802         if (data_sinfo->total_bytes - data_sinfo->bytes_used -
1803             data_sinfo->bytes_delalloc - data_sinfo->bytes_reserved -
1804             data_sinfo->bytes_pinned - data_sinfo->bytes_readonly -
1805             data_sinfo->bytes_may_use < bytes) {
1806                 struct btrfs_trans_handle *trans;
1807
1808                 /*
1809                  * if we don't have enough free bytes in this space then we need
1810                  * to alloc a new chunk.
1811                  */
1812                 if (!data_sinfo->full) {
1813                         u64 alloc_target;
1814
1815                         data_sinfo->force_alloc = 1;
1816                         spin_unlock(&data_sinfo->lock);
1817
1818                         alloc_target = btrfs_get_alloc_profile(root, 1);
1819                         trans = btrfs_start_transaction(root, 1);
1820                         if (!trans)
1821                                 return -ENOMEM;
1822
1823                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1824                                              bytes + 2 * 1024 * 1024,
1825                                              alloc_target, 0);
1826                         btrfs_end_transaction(trans, root);
1827                         if (ret)
1828                                 return ret;
1829                         goto again;
1830                 }
1831                 spin_unlock(&data_sinfo->lock);
1832
1833                 /* commit the current transaction and try again */
1834                 if (!committed) {
1835                         committed = 1;
1836                         trans = btrfs_join_transaction(root, 1);
1837                         if (!trans)
1838                                 return -ENOMEM;
1839                         ret = btrfs_commit_transaction(trans, root);
1840                         if (ret)
1841                                 return ret;
1842                         goto again;
1843                 }
1844
1845                 printk(KERN_ERR "no space left, need %llu, %llu delalloc bytes"
1846                        ", %llu bytes_used, %llu bytes_reserved, "
1847                        "%llu bytes_pinned, %llu bytes_readonly, %llu may use"
1848                        "%llu total\n", bytes, data_sinfo->bytes_delalloc,
1849                        data_sinfo->bytes_used, data_sinfo->bytes_reserved,
1850                        data_sinfo->bytes_pinned, data_sinfo->bytes_readonly,
1851                        data_sinfo->bytes_may_use, data_sinfo->total_bytes);
1852                 return -ENOSPC;
1853         }
1854         data_sinfo->bytes_may_use += bytes;
1855         BTRFS_I(inode)->reserved_bytes += bytes;
1856         spin_unlock(&data_sinfo->lock);
1857
1858         return btrfs_check_metadata_free_space(root);
1859 }
1860
1861 /*
1862  * if there was an error for whatever reason after calling
1863  * btrfs_check_data_free_space, call this so we can cleanup the counters.
1864  */
1865 void btrfs_free_reserved_data_space(struct btrfs_root *root,
1866                                     struct inode *inode, u64 bytes)
1867 {
1868         struct btrfs_space_info *data_sinfo;
1869
1870         /* make sure bytes are sectorsize aligned */
1871         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
1872
1873         data_sinfo = BTRFS_I(inode)->space_info;
1874         spin_lock(&data_sinfo->lock);
1875         data_sinfo->bytes_may_use -= bytes;
1876         BTRFS_I(inode)->reserved_bytes -= bytes;
1877         spin_unlock(&data_sinfo->lock);
1878 }
1879
1880 /* called when we are adding a delalloc extent to the inode's io_tree */
1881 void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
1882                                   u64 bytes)
1883 {
1884         struct btrfs_space_info *data_sinfo;
1885
1886         /* get the space info for where this inode will be storing its data */
1887         data_sinfo = BTRFS_I(inode)->space_info;
1888
1889         /* make sure we have enough space to handle the data first */
1890         spin_lock(&data_sinfo->lock);
1891         data_sinfo->bytes_delalloc += bytes;
1892
1893         /*
1894          * we are adding a delalloc extent without calling
1895          * btrfs_check_data_free_space first.  This happens on a weird
1896          * writepage condition, but shouldn't hurt our accounting
1897          */
1898         if (unlikely(bytes > BTRFS_I(inode)->reserved_bytes)) {
1899                 data_sinfo->bytes_may_use -= BTRFS_I(inode)->reserved_bytes;
1900                 BTRFS_I(inode)->reserved_bytes = 0;
1901         } else {
1902                 data_sinfo->bytes_may_use -= bytes;
1903                 BTRFS_I(inode)->reserved_bytes -= bytes;
1904         }
1905
1906         spin_unlock(&data_sinfo->lock);
1907 }
1908
1909 /* called when we are clearing an delalloc extent from the inode's io_tree */
1910 void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
1911                               u64 bytes)
1912 {
1913         struct btrfs_space_info *info;
1914
1915         info = BTRFS_I(inode)->space_info;
1916
1917         spin_lock(&info->lock);
1918         info->bytes_delalloc -= bytes;
1919         spin_unlock(&info->lock);
1920 }
1921
1922 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1923                           struct btrfs_root *extent_root, u64 alloc_bytes,
1924                           u64 flags, int force)
1925 {
1926         struct btrfs_space_info *space_info;
1927         u64 thresh;
1928         int ret = 0;
1929
1930         mutex_lock(&extent_root->fs_info->chunk_mutex);
1931
1932         flags = btrfs_reduce_alloc_profile(extent_root, flags);
1933
1934         space_info = __find_space_info(extent_root->fs_info, flags);
1935         if (!space_info) {
1936                 ret = update_space_info(extent_root->fs_info, flags,
1937                                         0, 0, &space_info);
1938                 BUG_ON(ret);
1939         }
1940         BUG_ON(!space_info);
1941
1942         spin_lock(&space_info->lock);
1943         if (space_info->force_alloc) {
1944                 force = 1;
1945                 space_info->force_alloc = 0;
1946         }
1947         if (space_info->full) {
1948                 spin_unlock(&space_info->lock);
1949                 goto out;
1950         }
1951
1952         thresh = space_info->total_bytes - space_info->bytes_readonly;
1953         thresh = div_factor(thresh, 6);
1954         if (!force &&
1955            (space_info->bytes_used + space_info->bytes_pinned +
1956             space_info->bytes_reserved + alloc_bytes) < thresh) {
1957                 spin_unlock(&space_info->lock);
1958                 goto out;
1959         }
1960         spin_unlock(&space_info->lock);
1961
1962         ret = btrfs_alloc_chunk(trans, extent_root, flags);
1963         if (ret)
1964                 space_info->full = 1;
1965 out:
1966         mutex_unlock(&extent_root->fs_info->chunk_mutex);
1967         return ret;
1968 }
1969
1970 static int update_block_group(struct btrfs_trans_handle *trans,
1971                               struct btrfs_root *root,
1972                               u64 bytenr, u64 num_bytes, int alloc,
1973                               int mark_free)
1974 {
1975         struct btrfs_block_group_cache *cache;
1976         struct btrfs_fs_info *info = root->fs_info;
1977         u64 total = num_bytes;
1978         u64 old_val;
1979         u64 byte_in_group;
1980
1981         while (total) {
1982                 cache = btrfs_lookup_block_group(info, bytenr);
1983                 if (!cache)
1984                         return -1;
1985                 byte_in_group = bytenr - cache->key.objectid;
1986                 WARN_ON(byte_in_group > cache->key.offset);
1987
1988                 spin_lock(&cache->space_info->lock);
1989                 spin_lock(&cache->lock);
1990                 cache->dirty = 1;
1991                 old_val = btrfs_block_group_used(&cache->item);
1992                 num_bytes = min(total, cache->key.offset - byte_in_group);
1993                 if (alloc) {
1994                         old_val += num_bytes;
1995                         cache->space_info->bytes_used += num_bytes;
1996                         if (cache->ro)
1997                                 cache->space_info->bytes_readonly -= num_bytes;
1998                         btrfs_set_block_group_used(&cache->item, old_val);
1999                         spin_unlock(&cache->lock);
2000                         spin_unlock(&cache->space_info->lock);
2001                 } else {
2002                         old_val -= num_bytes;
2003                         cache->space_info->bytes_used -= num_bytes;
2004                         if (cache->ro)
2005                                 cache->space_info->bytes_readonly += num_bytes;
2006                         btrfs_set_block_group_used(&cache->item, old_val);
2007                         spin_unlock(&cache->lock);
2008                         spin_unlock(&cache->space_info->lock);
2009                         if (mark_free) {
2010                                 int ret;
2011
2012                                 ret = btrfs_discard_extent(root, bytenr,
2013                                                            num_bytes);
2014                                 WARN_ON(ret);
2015
2016                                 ret = btrfs_add_free_space(cache, bytenr,
2017                                                            num_bytes);
2018                                 WARN_ON(ret);
2019                         }
2020                 }
2021                 put_block_group(cache);
2022                 total -= num_bytes;
2023                 bytenr += num_bytes;
2024         }
2025         return 0;
2026 }
2027
2028 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
2029 {
2030         struct btrfs_block_group_cache *cache;
2031         u64 bytenr;
2032
2033         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
2034         if (!cache)
2035                 return 0;
2036
2037         bytenr = cache->key.objectid;
2038         put_block_group(cache);
2039
2040         return bytenr;
2041 }
2042
2043 int btrfs_update_pinned_extents(struct btrfs_root *root,
2044                                 u64 bytenr, u64 num, int pin)
2045 {
2046         u64 len;
2047         struct btrfs_block_group_cache *cache;
2048         struct btrfs_fs_info *fs_info = root->fs_info;
2049
2050         WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
2051         if (pin) {
2052                 set_extent_dirty(&fs_info->pinned_extents,
2053                                 bytenr, bytenr + num - 1, GFP_NOFS);
2054         } else {
2055                 clear_extent_dirty(&fs_info->pinned_extents,
2056                                 bytenr, bytenr + num - 1, GFP_NOFS);
2057         }
2058         mutex_unlock(&root->fs_info->pinned_mutex);
2059
2060         while (num > 0) {
2061                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2062                 BUG_ON(!cache);
2063                 len = min(num, cache->key.offset -
2064                           (bytenr - cache->key.objectid));
2065                 if (pin) {
2066                         spin_lock(&cache->space_info->lock);
2067                         spin_lock(&cache->lock);
2068                         cache->pinned += len;
2069                         cache->space_info->bytes_pinned += len;
2070                         spin_unlock(&cache->lock);
2071                         spin_unlock(&cache->space_info->lock);
2072                         fs_info->total_pinned += len;
2073                 } else {
2074                         spin_lock(&cache->space_info->lock);
2075                         spin_lock(&cache->lock);
2076                         cache->pinned -= len;
2077                         cache->space_info->bytes_pinned -= len;
2078                         spin_unlock(&cache->lock);
2079                         spin_unlock(&cache->space_info->lock);
2080                         fs_info->total_pinned -= len;
2081                         if (cache->cached)
2082                                 btrfs_add_free_space(cache, bytenr, len);
2083                 }
2084                 put_block_group(cache);
2085                 bytenr += len;
2086                 num -= len;
2087         }
2088         return 0;
2089 }
2090
2091 static int update_reserved_extents(struct btrfs_root *root,
2092                                    u64 bytenr, u64 num, int reserve)
2093 {
2094         u64 len;
2095         struct btrfs_block_group_cache *cache;
2096         struct btrfs_fs_info *fs_info = root->fs_info;
2097
2098         while (num > 0) {
2099                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2100                 BUG_ON(!cache);
2101                 len = min(num, cache->key.offset -
2102                           (bytenr - cache->key.objectid));
2103
2104                 spin_lock(&cache->space_info->lock);
2105                 spin_lock(&cache->lock);
2106                 if (reserve) {
2107                         cache->reserved += len;
2108                         cache->space_info->bytes_reserved += len;
2109                 } else {
2110                         cache->reserved -= len;
2111                         cache->space_info->bytes_reserved -= len;
2112                 }
2113                 spin_unlock(&cache->lock);
2114                 spin_unlock(&cache->space_info->lock);
2115                 put_block_group(cache);
2116                 bytenr += len;
2117                 num -= len;
2118         }
2119         return 0;
2120 }
2121
2122 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
2123 {
2124         u64 last = 0;
2125         u64 start;
2126         u64 end;
2127         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
2128         int ret;
2129
2130         mutex_lock(&root->fs_info->pinned_mutex);
2131         while (1) {
2132                 ret = find_first_extent_bit(pinned_extents, last,
2133                                             &start, &end, EXTENT_DIRTY);
2134                 if (ret)
2135                         break;
2136                 set_extent_dirty(copy, start, end, GFP_NOFS);
2137                 last = end + 1;
2138         }
2139         mutex_unlock(&root->fs_info->pinned_mutex);
2140         return 0;
2141 }
2142
2143 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
2144                                struct btrfs_root *root,
2145                                struct extent_io_tree *unpin)
2146 {
2147         u64 start;
2148         u64 end;
2149         int ret;
2150
2151         while (1) {
2152                 mutex_lock(&root->fs_info->pinned_mutex);
2153                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2154                                             EXTENT_DIRTY);
2155                 if (ret)
2156                         break;
2157
2158                 ret = btrfs_discard_extent(root, start, end + 1 - start);
2159
2160                 /* unlocks the pinned mutex */
2161                 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
2162                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
2163
2164                 cond_resched();
2165         }
2166         mutex_unlock(&root->fs_info->pinned_mutex);
2167         return ret;
2168 }
2169
2170 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2171                           struct btrfs_root *root,
2172                           struct btrfs_path *path,
2173                           u64 bytenr, u64 num_bytes, int is_data,
2174                           struct extent_buffer **must_clean)
2175 {
2176         int err = 0;
2177         struct extent_buffer *buf;
2178
2179         if (is_data)
2180                 goto pinit;
2181
2182         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2183         if (!buf)
2184                 goto pinit;
2185
2186         /* we can reuse a block if it hasn't been written
2187          * and it is from this transaction.  We can't
2188          * reuse anything from the tree log root because
2189          * it has tiny sub-transactions.
2190          */
2191         if (btrfs_buffer_uptodate(buf, 0) &&
2192             btrfs_try_tree_lock(buf)) {
2193                 u64 header_owner = btrfs_header_owner(buf);
2194                 u64 header_transid = btrfs_header_generation(buf);
2195                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2196                     header_owner != BTRFS_TREE_RELOC_OBJECTID &&
2197                     header_owner != BTRFS_DATA_RELOC_TREE_OBJECTID &&
2198                     header_transid == trans->transid &&
2199                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2200                         *must_clean = buf;
2201                         return 1;
2202                 }
2203                 btrfs_tree_unlock(buf);
2204         }
2205         free_extent_buffer(buf);
2206 pinit:
2207         btrfs_set_path_blocking(path);
2208         mutex_lock(&root->fs_info->pinned_mutex);
2209         /* unlocks the pinned mutex */
2210         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
2211
2212         BUG_ON(err < 0);
2213         return 0;
2214 }
2215
2216 /*
2217  * remove an extent from the root, returns 0 on success
2218  */
2219 static int __free_extent(struct btrfs_trans_handle *trans,
2220                          struct btrfs_root *root,
2221                          u64 bytenr, u64 num_bytes, u64 parent,
2222                          u64 root_objectid, u64 ref_generation,
2223                          u64 owner_objectid, int pin, int mark_free,
2224                          int refs_to_drop)
2225 {
2226         struct btrfs_path *path;
2227         struct btrfs_key key;
2228         struct btrfs_fs_info *info = root->fs_info;
2229         struct btrfs_root *extent_root = info->extent_root;
2230         struct extent_buffer *leaf;
2231         int ret;
2232         int extent_slot = 0;
2233         int found_extent = 0;
2234         int num_to_del = 1;
2235         struct btrfs_extent_item *ei;
2236         u32 refs;
2237
2238         key.objectid = bytenr;
2239         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
2240         key.offset = num_bytes;
2241         path = btrfs_alloc_path();
2242         if (!path)
2243                 return -ENOMEM;
2244
2245         path->reada = 1;
2246         path->leave_spinning = 1;
2247         ret = lookup_extent_backref(trans, extent_root, path,
2248                                     bytenr, parent, root_objectid,
2249                                     ref_generation, owner_objectid, 1);
2250         if (ret == 0) {
2251                 struct btrfs_key found_key;
2252                 extent_slot = path->slots[0];
2253                 while (extent_slot > 0) {
2254                         extent_slot--;
2255                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2256                                               extent_slot);
2257                         if (found_key.objectid != bytenr)
2258                                 break;
2259                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
2260                             found_key.offset == num_bytes) {
2261                                 found_extent = 1;
2262                                 break;
2263                         }
2264                         if (path->slots[0] - extent_slot > 5)
2265                                 break;
2266                 }
2267                 if (!found_extent) {
2268                         ret = remove_extent_backref(trans, extent_root, path,
2269                                                     refs_to_drop);
2270                         BUG_ON(ret);
2271                         btrfs_release_path(extent_root, path);
2272                         path->leave_spinning = 1;
2273                         ret = btrfs_search_slot(trans, extent_root,
2274                                                 &key, path, -1, 1);
2275                         if (ret) {
2276                                 printk(KERN_ERR "umm, got %d back from search"
2277                                        ", was looking for %llu\n", ret,
2278                                        (unsigned long long)bytenr);
2279                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2280                         }
2281                         BUG_ON(ret);
2282                         extent_slot = path->slots[0];
2283                 }
2284         } else {
2285                 btrfs_print_leaf(extent_root, path->nodes[0]);
2286                 WARN_ON(1);
2287                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2288                        "parent %llu root %llu gen %llu owner %llu\n",
2289                        (unsigned long long)bytenr,
2290                        (unsigned long long)parent,
2291                        (unsigned long long)root_objectid,
2292                        (unsigned long long)ref_generation,
2293                        (unsigned long long)owner_objectid);
2294         }
2295
2296         leaf = path->nodes[0];
2297         ei = btrfs_item_ptr(leaf, extent_slot,
2298                             struct btrfs_extent_item);
2299         refs = btrfs_extent_refs(leaf, ei);
2300
2301         /*
2302          * we're not allowed to delete the extent item if there
2303          * are other delayed ref updates pending
2304          */
2305
2306         BUG_ON(refs < refs_to_drop);
2307         refs -= refs_to_drop;
2308         btrfs_set_extent_refs(leaf, ei, refs);
2309         btrfs_mark_buffer_dirty(leaf);
2310
2311         if (refs == 0 && found_extent &&
2312             path->slots[0] == extent_slot + 1) {
2313                 struct btrfs_extent_ref *ref;
2314                 ref = btrfs_item_ptr(leaf, path->slots[0],
2315                                      struct btrfs_extent_ref);
2316                 BUG_ON(btrfs_ref_num_refs(leaf, ref) != refs_to_drop);
2317                 /* if the back ref and the extent are next to each other
2318                  * they get deleted below in one shot
2319                  */
2320                 path->slots[0] = extent_slot;
2321                 num_to_del = 2;
2322         } else if (found_extent) {
2323                 /* otherwise delete the extent back ref */
2324                 ret = remove_extent_backref(trans, extent_root, path,
2325                                             refs_to_drop);
2326                 BUG_ON(ret);
2327                 /* if refs are 0, we need to setup the path for deletion */
2328                 if (refs == 0) {
2329                         btrfs_release_path(extent_root, path);
2330                         path->leave_spinning = 1;
2331                         ret = btrfs_search_slot(trans, extent_root, &key, path,
2332                                                 -1, 1);
2333                         BUG_ON(ret);
2334                 }
2335         }
2336
2337         if (refs == 0) {
2338                 u64 super_used;
2339                 u64 root_used;
2340                 struct extent_buffer *must_clean = NULL;
2341
2342                 if (pin) {
2343                         ret = pin_down_bytes(trans, root, path,
2344                                 bytenr, num_bytes,
2345                                 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID,
2346                                 &must_clean);
2347                         if (ret > 0)
2348                                 mark_free = 1;
2349                         BUG_ON(ret < 0);
2350                 }
2351
2352                 /* block accounting for super block */
2353                 spin_lock(&info->delalloc_lock);
2354                 super_used = btrfs_super_bytes_used(&info->super_copy);
2355                 btrfs_set_super_bytes_used(&info->super_copy,
2356                                            super_used - num_bytes);
2357
2358                 /* block accounting for root item */
2359                 root_used = btrfs_root_used(&root->root_item);
2360                 btrfs_set_root_used(&root->root_item,
2361                                            root_used - num_bytes);
2362                 spin_unlock(&info->delalloc_lock);
2363
2364                 /*
2365                  * it is going to be very rare for someone to be waiting
2366                  * on the block we're freeing.  del_items might need to
2367                  * schedule, so rather than get fancy, just force it
2368                  * to blocking here
2369                  */
2370                 if (must_clean)
2371                         btrfs_set_lock_blocking(must_clean);
2372
2373                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2374                                       num_to_del);
2375                 BUG_ON(ret);
2376                 btrfs_release_path(extent_root, path);
2377
2378                 if (must_clean) {
2379                         clean_tree_block(NULL, root, must_clean);
2380                         btrfs_tree_unlock(must_clean);
2381                         free_extent_buffer(must_clean);
2382                 }
2383
2384                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2385                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2386                         BUG_ON(ret);
2387                 } else {
2388                         invalidate_mapping_pages(info->btree_inode->i_mapping,
2389                              bytenr >> PAGE_CACHE_SHIFT,
2390                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
2391                 }
2392
2393                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
2394                                          mark_free);
2395                 BUG_ON(ret);
2396         }
2397         btrfs_free_path(path);
2398         return ret;
2399 }
2400
2401 /*
2402  * remove an extent from the root, returns 0 on success
2403  */
2404 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2405                                         struct btrfs_root *root,
2406                                         u64 bytenr, u64 num_bytes, u64 parent,
2407                                         u64 root_objectid, u64 ref_generation,
2408                                         u64 owner_objectid, int pin,
2409                                         int refs_to_drop)
2410 {
2411         WARN_ON(num_bytes < root->sectorsize);
2412
2413         /*
2414          * if metadata always pin
2415          * if data pin when any transaction has committed this
2416          */
2417         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID ||
2418             ref_generation != trans->transid)
2419                 pin = 1;
2420
2421         if (ref_generation != trans->transid)
2422                 pin = 1;
2423
2424         return __free_extent(trans, root, bytenr, num_bytes, parent,
2425                             root_objectid, ref_generation,
2426                             owner_objectid, pin, pin == 0, refs_to_drop);
2427 }
2428
2429 /*
2430  * when we free an extent, it is possible (and likely) that we free the last
2431  * delayed ref for that extent as well.  This searches the delayed ref tree for
2432  * a given extent, and if there are no other delayed refs to be processed, it
2433  * removes it from the tree.
2434  */
2435 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
2436                                       struct btrfs_root *root, u64 bytenr)
2437 {
2438         struct btrfs_delayed_ref_head *head;
2439         struct btrfs_delayed_ref_root *delayed_refs;
2440         struct btrfs_delayed_ref_node *ref;
2441         struct rb_node *node;
2442         int ret;
2443
2444         delayed_refs = &trans->transaction->delayed_refs;
2445         spin_lock(&delayed_refs->lock);
2446         head = btrfs_find_delayed_ref_head(trans, bytenr);
2447         if (!head)
2448                 goto out;
2449
2450         node = rb_prev(&head->node.rb_node);
2451         if (!node)
2452                 goto out;
2453
2454         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2455
2456         /* there are still entries for this ref, we can't drop it */
2457         if (ref->bytenr == bytenr)
2458                 goto out;
2459
2460         /*
2461          * waiting for the lock here would deadlock.  If someone else has it
2462          * locked they are already in the process of dropping it anyway
2463          */
2464         if (!mutex_trylock(&head->mutex))
2465                 goto out;
2466
2467         /*
2468          * at this point we have a head with no other entries.  Go
2469          * ahead and process it.
2470          */
2471         head->node.in_tree = 0;
2472         rb_erase(&head->node.rb_node, &delayed_refs->root);
2473
2474         delayed_refs->num_entries--;
2475
2476         /*
2477          * we don't take a ref on the node because we're removing it from the
2478          * tree, so we just steal the ref the tree was holding.
2479          */
2480         delayed_refs->num_heads--;
2481         if (list_empty(&head->cluster))
2482                 delayed_refs->num_heads_ready--;
2483
2484         list_del_init(&head->cluster);
2485         spin_unlock(&delayed_refs->lock);
2486
2487         ret = run_one_delayed_ref(trans, root->fs_info->tree_root,
2488                                   &head->node, head->must_insert_reserved);
2489         BUG_ON(ret);
2490         btrfs_put_delayed_ref(&head->node);
2491         return 0;
2492 out:
2493         spin_unlock(&delayed_refs->lock);
2494         return 0;
2495 }
2496
2497 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2498                       struct btrfs_root *root,
2499                       u64 bytenr, u64 num_bytes, u64 parent,
2500                       u64 root_objectid, u64 ref_generation,
2501                       u64 owner_objectid, int pin)
2502 {
2503         int ret;
2504
2505         /*
2506          * tree log blocks never actually go into the extent allocation
2507          * tree, just update pinning info and exit early.
2508          *
2509          * data extents referenced by the tree log do need to have
2510          * their reference counts bumped.
2511          */
2512         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID &&
2513             owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2514                 mutex_lock(&root->fs_info->pinned_mutex);
2515
2516                 /* unlocks the pinned mutex */
2517                 btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
2518                 update_reserved_extents(root, bytenr, num_bytes, 0);
2519                 ret = 0;
2520         } else {
2521                 ret = btrfs_add_delayed_ref(trans, bytenr, num_bytes, parent,
2522                                        root_objectid, ref_generation,
2523                                        owner_objectid,
2524                                        BTRFS_DROP_DELAYED_REF, 1);
2525                 BUG_ON(ret);
2526                 ret = check_ref_cleanup(trans, root, bytenr);
2527                 BUG_ON(ret);
2528         }
2529         return ret;
2530 }
2531
2532 static u64 stripe_align(struct btrfs_root *root, u64 val)
2533 {
2534         u64 mask = ((u64)root->stripesize - 1);
2535         u64 ret = (val + mask) & ~mask;
2536         return ret;
2537 }
2538
2539 /*
2540  * walks the btree of allocated extents and find a hole of a given size.
2541  * The key ins is changed to record the hole:
2542  * ins->objectid == block start
2543  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2544  * ins->offset == number of blocks
2545  * Any available blocks before search_start are skipped.
2546  */
2547 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
2548                                      struct btrfs_root *orig_root,
2549                                      u64 num_bytes, u64 empty_size,
2550                                      u64 search_start, u64 search_end,
2551                                      u64 hint_byte, struct btrfs_key *ins,
2552                                      u64 exclude_start, u64 exclude_nr,
2553                                      int data)
2554 {
2555         int ret = 0;
2556         struct btrfs_root *root = orig_root->fs_info->extent_root;
2557         u64 total_needed = num_bytes;
2558         u64 *last_ptr = NULL;
2559         u64 last_wanted = 0;
2560         struct btrfs_block_group_cache *block_group = NULL;
2561         int chunk_alloc_done = 0;
2562         int empty_cluster = 2 * 1024 * 1024;
2563         int allowed_chunk_alloc = 0;
2564         struct list_head *head = NULL, *cur = NULL;
2565         int loop = 0;
2566         int extra_loop = 0;
2567         struct btrfs_space_info *space_info;
2568
2569         WARN_ON(num_bytes < root->sectorsize);
2570         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2571         ins->objectid = 0;
2572         ins->offset = 0;
2573
2574         if (orig_root->ref_cows || empty_size)
2575                 allowed_chunk_alloc = 1;
2576
2577         if (data & BTRFS_BLOCK_GROUP_METADATA) {
2578                 last_ptr = &root->fs_info->last_alloc;
2579                 if (!btrfs_test_opt(root, SSD))
2580                         empty_cluster = 64 * 1024;
2581         }
2582
2583         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
2584                 last_ptr = &root->fs_info->last_data_alloc;
2585
2586         if (last_ptr) {
2587                 if (*last_ptr) {
2588                         hint_byte = *last_ptr;
2589                         last_wanted = *last_ptr;
2590                 } else
2591                         empty_size += empty_cluster;
2592         } else {
2593                 empty_cluster = 0;
2594         }
2595         search_start = max(search_start, first_logical_byte(root, 0));
2596         search_start = max(search_start, hint_byte);
2597
2598         if (last_wanted && search_start != last_wanted) {
2599                 last_wanted = 0;
2600                 empty_size += empty_cluster;
2601         }
2602
2603         total_needed += empty_size;
2604         block_group = btrfs_lookup_block_group(root->fs_info, search_start);
2605         if (!block_group)
2606                 block_group = btrfs_lookup_first_block_group(root->fs_info,
2607                                                              search_start);
2608         space_info = __find_space_info(root->fs_info, data);
2609
2610         down_read(&space_info->groups_sem);
2611         while (1) {
2612                 struct btrfs_free_space *free_space;
2613                 /*
2614                  * the only way this happens if our hint points to a block
2615                  * group thats not of the proper type, while looping this
2616                  * should never happen
2617                  */
2618                 if (empty_size)
2619                         extra_loop = 1;
2620
2621                 if (!block_group)
2622                         goto new_group_no_lock;
2623
2624                 if (unlikely(!block_group->cached)) {
2625                         mutex_lock(&block_group->cache_mutex);
2626                         ret = cache_block_group(root, block_group);
2627                         mutex_unlock(&block_group->cache_mutex);
2628                         if (ret)
2629                                 break;
2630                 }
2631
2632                 mutex_lock(&block_group->alloc_mutex);
2633                 if (unlikely(!block_group_bits(block_group, data)))
2634                         goto new_group;
2635
2636                 if (unlikely(block_group->ro))
2637                         goto new_group;
2638
2639                 free_space = btrfs_find_free_space(block_group, search_start,
2640                                                    total_needed);
2641                 if (free_space) {
2642                         u64 start = block_group->key.objectid;
2643                         u64 end = block_group->key.objectid +
2644                                 block_group->key.offset;
2645
2646                         search_start = stripe_align(root, free_space->offset);
2647
2648                         /* move on to the next group */
2649                         if (search_start + num_bytes >= search_end)
2650                                 goto new_group;
2651
2652                         /* move on to the next group */
2653                         if (search_start + num_bytes > end)
2654                                 goto new_group;
2655
2656                         if (last_wanted && search_start != last_wanted) {
2657                                 total_needed += empty_cluster;
2658                                 empty_size += empty_cluster;
2659                                 last_wanted = 0;
2660                                 /*
2661                                  * if search_start is still in this block group
2662                                  * then we just re-search this block group
2663                                  */
2664                                 if (search_start >= start &&
2665                                     search_start < end) {
2666                                         mutex_unlock(&block_group->alloc_mutex);
2667                                         continue;
2668                                 }
2669
2670                                 /* else we go to the next block group */
2671                                 goto new_group;
2672                         }
2673
2674                         if (exclude_nr > 0 &&
2675                             (search_start + num_bytes > exclude_start &&
2676                              search_start < exclude_start + exclude_nr)) {
2677                                 search_start = exclude_start + exclude_nr;
2678                                 /*
2679                                  * if search_start is still in this block group
2680                                  * then we just re-search this block group
2681                                  */
2682                                 if (search_start >= start &&
2683                                     search_start < end) {
2684                                         mutex_unlock(&block_group->alloc_mutex);
2685                                         last_wanted = 0;
2686                                         continue;
2687                                 }
2688
2689                                 /* else we go to the next block group */
2690                                 goto new_group;
2691                         }
2692
2693                         ins->objectid = search_start;
2694                         ins->offset = num_bytes;
2695
2696                         btrfs_remove_free_space_lock(block_group, search_start,
2697                                                      num_bytes);
2698                         /* we are all good, lets return */
2699                         mutex_unlock(&block_group->alloc_mutex);
2700                         break;
2701                 }
2702 new_group:
2703                 mutex_unlock(&block_group->alloc_mutex);
2704                 put_block_group(block_group);
2705                 block_group = NULL;
2706 new_group_no_lock:
2707                 /* don't try to compare new allocations against the
2708                  * last allocation any more
2709                  */
2710                 last_wanted = 0;
2711
2712                 /*
2713                  * Here's how this works.
2714                  * loop == 0: we were searching a block group via a hint
2715                  *              and didn't find anything, so we start at
2716                  *              the head of the block groups and keep searching
2717                  * loop == 1: we're searching through all of the block groups
2718                  *              if we hit the head again we have searched
2719                  *              all of the block groups for this space and we
2720                  *              need to try and allocate, if we cant error out.
2721                  * loop == 2: we allocated more space and are looping through
2722                  *              all of the block groups again.
2723                  */
2724                 if (loop == 0) {
2725                         head = &space_info->block_groups;
2726                         cur = head->next;
2727                         loop++;
2728                 } else if (loop == 1 && cur == head) {
2729                         int keep_going;
2730
2731                         /* at this point we give up on the empty_size
2732                          * allocations and just try to allocate the min
2733                          * space.
2734                          *
2735                          * The extra_loop field was set if an empty_size
2736                          * allocation was attempted above, and if this
2737                          * is try we need to try the loop again without
2738                          * the additional empty_size.
2739                          */
2740                         total_needed -= empty_size;
2741                         empty_size = 0;
2742                         keep_going = extra_loop;
2743                         loop++;
2744
2745                         if (allowed_chunk_alloc && !chunk_alloc_done) {
2746                                 up_read(&space_info->groups_sem);
2747                                 ret = do_chunk_alloc(trans, root, num_bytes +
2748                                                      2 * 1024 * 1024, data, 1);
2749                                 down_read(&space_info->groups_sem);
2750                                 if (ret < 0)
2751                                         goto loop_check;
2752                                 head = &space_info->block_groups;
2753                                 /*
2754                                  * we've allocated a new chunk, keep
2755                                  * trying
2756                                  */
2757                                 keep_going = 1;
2758                                 chunk_alloc_done = 1;
2759                         } else if (!allowed_chunk_alloc) {
2760                                 space_info->force_alloc = 1;
2761                         }
2762 loop_check:
2763                         if (keep_going) {
2764                                 cur = head->next;
2765                                 extra_loop = 0;
2766                         } else {
2767                                 break;
2768                         }
2769                 } else if (cur == head) {
2770                         break;
2771                 }
2772
2773                 block_group = list_entry(cur, struct btrfs_block_group_cache,
2774                                          list);
2775                 atomic_inc(&block_group->count);
2776
2777                 search_start = block_group->key.objectid;
2778                 cur = cur->next;
2779         }
2780
2781         /* we found what we needed */
2782         if (ins->objectid) {
2783                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
2784                         trans->block_group = block_group->key.objectid;
2785
2786                 if (last_ptr)
2787                         *last_ptr = ins->objectid + ins->offset;
2788                 ret = 0;
2789         } else if (!ret) {
2790                 printk(KERN_ERR "btrfs searching for %llu bytes, "
2791                        "num_bytes %llu, loop %d, allowed_alloc %d\n",
2792                        (unsigned long long)total_needed,
2793                        (unsigned long long)num_bytes,
2794                        loop, allowed_chunk_alloc);
2795                 ret = -ENOSPC;
2796         }
2797         if (block_group)
2798                 put_block_group(block_group);
2799
2800         up_read(&space_info->groups_sem);
2801         return ret;
2802 }
2803
2804 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
2805 {
2806         struct btrfs_block_group_cache *cache;
2807
2808         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
2809                (unsigned long long)(info->total_bytes - info->bytes_used -
2810                                     info->bytes_pinned - info->bytes_reserved),
2811                (info->full) ? "" : "not ");
2812         printk(KERN_INFO "space_info total=%llu, pinned=%llu, delalloc=%llu,"
2813                " may_use=%llu, used=%llu\n", info->total_bytes,
2814                info->bytes_pinned, info->bytes_delalloc, info->bytes_may_use,
2815                info->bytes_used);
2816
2817         down_read(&info->groups_sem);
2818         list_for_each_entry(cache, &info->block_groups, list) {
2819                 spin_lock(&cache->lock);
2820                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
2821                        "%llu pinned %llu reserved\n",
2822                        (unsigned long long)cache->key.objectid,
2823                        (unsigned long long)cache->key.offset,
2824                        (unsigned long long)btrfs_block_group_used(&cache->item),
2825                        (unsigned long long)cache->pinned,
2826                        (unsigned long long)cache->reserved);
2827                 btrfs_dump_free_space(cache, bytes);
2828                 spin_unlock(&cache->lock);
2829         }
2830         up_read(&info->groups_sem);
2831 }
2832
2833 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2834                                   struct btrfs_root *root,
2835                                   u64 num_bytes, u64 min_alloc_size,
2836                                   u64 empty_size, u64 hint_byte,
2837                                   u64 search_end, struct btrfs_key *ins,
2838                                   u64 data)
2839 {
2840         int ret;
2841         u64 search_start = 0;
2842         struct btrfs_fs_info *info = root->fs_info;
2843
2844         data = btrfs_get_alloc_profile(root, data);
2845 again:
2846         /*
2847          * the only place that sets empty_size is btrfs_realloc_node, which
2848          * is not called recursively on allocations
2849          */
2850         if (empty_size || root->ref_cows) {
2851                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2852                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2853                                      2 * 1024 * 1024,
2854                                      BTRFS_BLOCK_GROUP_METADATA |
2855                                      (info->metadata_alloc_profile &
2856                                       info->avail_metadata_alloc_bits), 0);
2857                 }
2858                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2859                                      num_bytes + 2 * 1024 * 1024, data, 0);
2860         }
2861
2862         WARN_ON(num_bytes < root->sectorsize);
2863         ret = find_free_extent(trans, root, num_bytes, empty_size,
2864                                search_start, search_end, hint_byte, ins,
2865                                trans->alloc_exclude_start,
2866                                trans->alloc_exclude_nr, data);
2867
2868         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
2869                 num_bytes = num_bytes >> 1;
2870                 num_bytes = num_bytes & ~(root->sectorsize - 1);
2871                 num_bytes = max(num_bytes, min_alloc_size);
2872                 do_chunk_alloc(trans, root->fs_info->extent_root,
2873                                num_bytes, data, 1);
2874                 goto again;
2875         }
2876         if (ret) {
2877                 struct btrfs_space_info *sinfo;
2878
2879                 sinfo = __find_space_info(root->fs_info, data);
2880                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
2881                        "wanted %llu\n", (unsigned long long)data,
2882                        (unsigned long long)num_bytes);
2883                 dump_space_info(sinfo, num_bytes);
2884                 BUG();
2885         }
2886
2887         return ret;
2888 }
2889
2890 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
2891 {
2892         struct btrfs_block_group_cache *cache;
2893         int ret = 0;
2894
2895         cache = btrfs_lookup_block_group(root->fs_info, start);
2896         if (!cache) {
2897                 printk(KERN_ERR "Unable to find block group for %llu\n",
2898                        (unsigned long long)start);
2899                 return -ENOSPC;
2900         }
2901
2902         ret = btrfs_discard_extent(root, start, len);
2903
2904         btrfs_add_free_space(cache, start, len);
2905         put_block_group(cache);
2906         update_reserved_extents(root, start, len, 0);
2907
2908         return ret;
2909 }
2910
2911 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2912                                   struct btrfs_root *root,
2913                                   u64 num_bytes, u64 min_alloc_size,
2914                                   u64 empty_size, u64 hint_byte,
2915                                   u64 search_end, struct btrfs_key *ins,
2916                                   u64 data)
2917 {
2918         int ret;
2919         ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
2920                                      empty_size, hint_byte, search_end, ins,
2921                                      data);
2922         update_reserved_extents(root, ins->objectid, ins->offset, 1);
2923         return ret;
2924 }
2925
2926 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2927                                          struct btrfs_root *root, u64 parent,
2928                                          u64 root_objectid, u64 ref_generation,
2929                                          u64 owner, struct btrfs_key *ins,
2930                                          int ref_mod)
2931 {
2932         int ret;
2933         u64 super_used;
2934         u64 root_used;
2935         u64 num_bytes = ins->offset;
2936         u32 sizes[2];
2937         struct btrfs_fs_info *info = root->fs_info;
2938         struct btrfs_root *extent_root = info->extent_root;
2939         struct btrfs_extent_item *extent_item;
2940         struct btrfs_extent_ref *ref;
2941         struct btrfs_path *path;
2942         struct btrfs_key keys[2];
2943
2944         if (parent == 0)
2945                 parent = ins->objectid;
2946
2947         /* block accounting for super block */
2948         spin_lock(&info->delalloc_lock);
2949         super_used = btrfs_super_bytes_used(&info->super_copy);
2950         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
2951
2952         /* block accounting for root item */
2953         root_used = btrfs_root_used(&root->root_item);
2954         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
2955         spin_unlock(&info->delalloc_lock);
2956
2957         memcpy(&keys[0], ins, sizeof(*ins));
2958         keys[1].objectid = ins->objectid;
2959         keys[1].type = BTRFS_EXTENT_REF_KEY;
2960         keys[1].offset = parent;
2961         sizes[0] = sizeof(*extent_item);
2962         sizes[1] = sizeof(*ref);
2963
2964         path = btrfs_alloc_path();
2965         BUG_ON(!path);
2966
2967         path->leave_spinning = 1;
2968         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2969                                        sizes, 2);
2970         BUG_ON(ret);
2971
2972         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2973                                      struct btrfs_extent_item);
2974         btrfs_set_extent_refs(path->nodes[0], extent_item, ref_mod);
2975         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2976                              struct btrfs_extent_ref);
2977
2978         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2979         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2980         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2981         btrfs_set_ref_num_refs(path->nodes[0], ref, ref_mod);
2982
2983         btrfs_mark_buffer_dirty(path->nodes[0]);
2984
2985         trans->alloc_exclude_start = 0;
2986         trans->alloc_exclude_nr = 0;
2987         btrfs_free_path(path);
2988
2989         if (ret)
2990                 goto out;
2991
2992         ret = update_block_group(trans, root, ins->objectid,
2993                                  ins->offset, 1, 0);
2994         if (ret) {
2995                 printk(KERN_ERR "btrfs update block group failed for %llu "
2996                        "%llu\n", (unsigned long long)ins->objectid,
2997                        (unsigned long long)ins->offset);
2998                 BUG();
2999         }
3000 out:
3001         return ret;
3002 }
3003
3004 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
3005                                 struct btrfs_root *root, u64 parent,
3006                                 u64 root_objectid, u64 ref_generation,
3007                                 u64 owner, struct btrfs_key *ins)
3008 {
3009         int ret;
3010
3011         if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
3012                 return 0;
3013
3014         ret = btrfs_add_delayed_ref(trans, ins->objectid,
3015                                     ins->offset, parent, root_objectid,
3016                                     ref_generation, owner,
3017                                     BTRFS_ADD_DELAYED_EXTENT, 0);
3018         BUG_ON(ret);
3019         return ret;
3020 }
3021
3022 /*
3023  * this is used by the tree logging recovery code.  It records that
3024  * an extent has been allocated and makes sure to clear the free
3025  * space cache bits as well
3026  */
3027 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
3028                                 struct btrfs_root *root, u64 parent,
3029                                 u64 root_objectid, u64 ref_generation,
3030                                 u64 owner, struct btrfs_key *ins)
3031 {
3032         int ret;
3033         struct btrfs_block_group_cache *block_group;
3034
3035         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
3036         mutex_lock(&block_group->cache_mutex);
3037         cache_block_group(root, block_group);
3038         mutex_unlock(&block_group->cache_mutex);
3039
3040         ret = btrfs_remove_free_space(block_group, ins->objectid,
3041                                       ins->offset);
3042         BUG_ON(ret);
3043         put_block_group(block_group);
3044         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
3045                                             ref_generation, owner, ins, 1);
3046         return ret;
3047 }
3048
3049 /*
3050  * finds a free extent and does all the dirty work required for allocation
3051  * returns the key for the extent through ins, and a tree buffer for
3052  * the first block of the extent through buf.
3053  *
3054  * returns 0 if everything worked, non-zero otherwise.
3055  */
3056 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
3057                        struct btrfs_root *root,
3058                        u64 num_bytes, u64 parent, u64 min_alloc_size,
3059                        u64 root_objectid, u64 ref_generation,
3060                        u64 owner_objectid, u64 empty_size, u64 hint_byte,
3061                        u64 search_end, struct btrfs_key *ins, u64 data)
3062 {
3063         int ret;
3064         ret = __btrfs_reserve_extent(trans, root, num_bytes,
3065                                      min_alloc_size, empty_size, hint_byte,
3066                                      search_end, ins, data);
3067         BUG_ON(ret);
3068         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
3069                 ret = btrfs_add_delayed_ref(trans, ins->objectid,
3070                                             ins->offset, parent, root_objectid,
3071                                             ref_generation, owner_objectid,
3072                                             BTRFS_ADD_DELAYED_EXTENT, 0);
3073                 BUG_ON(ret);
3074         }
3075         update_reserved_extents(root, ins->objectid, ins->offset, 1);
3076         return ret;
3077 }
3078
3079 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
3080                                             struct btrfs_root *root,
3081                                             u64 bytenr, u32 blocksize,
3082                                             int level)
3083 {
3084         struct extent_buffer *buf;
3085
3086         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
3087         if (!buf)
3088                 return ERR_PTR(-ENOMEM);
3089         btrfs_set_header_generation(buf, trans->transid);
3090         btrfs_set_buffer_lockdep_class(buf, level);
3091         btrfs_tree_lock(buf);
3092         clean_tree_block(trans, root, buf);
3093
3094         btrfs_set_lock_blocking(buf);
3095         btrfs_set_buffer_uptodate(buf);
3096
3097         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
3098                 set_extent_dirty(&root->dirty_log_pages, buf->start,
3099                          buf->start + buf->len - 1, GFP_NOFS);
3100         } else {
3101                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
3102                          buf->start + buf->len - 1, GFP_NOFS);
3103         }
3104         trans->blocks_used++;
3105         /* this returns a buffer locked for blocking */
3106         return buf;
3107 }
3108
3109 /*
3110  * helper function to allocate a block for a given tree
3111  * returns the tree buffer or NULL.
3112  */
3113 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
3114                                              struct btrfs_root *root,
3115                                              u32 blocksize, u64 parent,
3116                                              u64 root_objectid,
3117                                              u64 ref_generation,
3118                                              int level,
3119                                              u64 hint,
3120                                              u64 empty_size)
3121 {
3122         struct btrfs_key ins;
3123         int ret;
3124         struct extent_buffer *buf;
3125
3126         ret = btrfs_alloc_extent(trans, root, blocksize, parent, blocksize,
3127                                  root_objectid, ref_generation, level,
3128                                  empty_size, hint, (u64)-1, &ins, 0);
3129         if (ret) {
3130                 BUG_ON(ret > 0);
3131                 return ERR_PTR(ret);
3132         }
3133
3134         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
3135                                     blocksize, level);
3136         return buf;
3137 }
3138
3139 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
3140                         struct btrfs_root *root, struct extent_buffer *leaf)
3141 {
3142         u64 leaf_owner;
3143         u64 leaf_generation;
3144         struct refsort *sorted;
3145         struct btrfs_key key;
3146         struct btrfs_file_extent_item *fi;
3147         int i;
3148         int nritems;
3149         int ret;
3150         int refi = 0;
3151         int slot;
3152
3153         BUG_ON(!btrfs_is_leaf(leaf));
3154         nritems = btrfs_header_nritems(leaf);
3155         leaf_owner = btrfs_header_owner(leaf);
3156         leaf_generation = btrfs_header_generation(leaf);
3157
3158         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3159         /* we do this loop twice.  The first time we build a list
3160          * of the extents we have a reference on, then we sort the list
3161          * by bytenr.  The second time around we actually do the
3162          * extent freeing.
3163          */
3164         for (i = 0; i < nritems; i++) {
3165                 u64 disk_bytenr;
3166                 cond_resched();
3167
3168                 btrfs_item_key_to_cpu(leaf, &key, i);
3169
3170                 /* only extents have references, skip everything else */
3171                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3172                         continue;
3173
3174                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3175
3176                 /* inline extents live in the btree, they don't have refs */
3177                 if (btrfs_file_extent_type(leaf, fi) ==
3178                     BTRFS_FILE_EXTENT_INLINE)
3179                         continue;
3180
3181                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
3182
3183                 /* holes don't have refs */
3184                 if (disk_bytenr == 0)
3185                         continue;
3186
3187                 sorted[refi].bytenr = disk_bytenr;
3188                 sorted[refi].slot = i;
3189                 refi++;
3190         }
3191
3192         if (refi == 0)
3193                 goto out;
3194
3195         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3196
3197         for (i = 0; i < refi; i++) {
3198                 u64 disk_bytenr;
3199
3200                 disk_bytenr = sorted[i].bytenr;
3201                 slot = sorted[i].slot;
3202
3203                 cond_resched();
3204
3205                 btrfs_item_key_to_cpu(leaf, &key, slot);
3206                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3207                         continue;
3208
3209                 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
3210
3211                 ret = btrfs_free_extent(trans, root, disk_bytenr,
3212                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
3213                                 leaf->start, leaf_owner, leaf_generation,
3214                                 key.objectid, 0);
3215                 BUG_ON(ret);
3216
3217                 atomic_inc(&root->fs_info->throttle_gen);
3218                 wake_up(&root->fs_info->transaction_throttle);
3219                 cond_resched();
3220         }
3221 out:
3222         kfree(sorted);
3223         return 0;
3224 }
3225
3226 static noinline int cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
3227                                         struct btrfs_root *root,
3228                                         struct btrfs_leaf_ref *ref)
3229 {
3230         int i;
3231         int ret;
3232         struct btrfs_extent_info *info;
3233         struct refsort *sorted;
3234
3235         if (ref->nritems == 0)
3236                 return 0;
3237
3238         sorted = kmalloc(sizeof(*sorted) * ref->nritems, GFP_NOFS);
3239         for (i = 0; i < ref->nritems; i++) {
3240                 sorted[i].bytenr = ref->extents[i].bytenr;
3241                 sorted[i].slot = i;
3242         }
3243         sort(sorted, ref->nritems, sizeof(struct refsort), refsort_cmp, NULL);
3244
3245         /*
3246          * the items in the ref were sorted when the ref was inserted
3247          * into the ref cache, so this is already in order
3248          */
3249         for (i = 0; i < ref->nritems; i++) {
3250                 info = ref->extents + sorted[i].slot;
3251                 ret = btrfs_free_extent(trans, root, info->bytenr,
3252                                           info->num_bytes, ref->bytenr,
3253                                           ref->owner, ref->generation,
3254                                           info->objectid, 0);
3255
3256                 atomic_inc(&root->fs_info->throttle_gen);
3257                 wake_up(&root->fs_info->transaction_throttle);
3258                 cond_resched();
3259
3260                 BUG_ON(ret);
3261                 info++;
3262         }
3263
3264         kfree(sorted);
3265         return 0;
3266 }
3267
3268 static int drop_snap_lookup_refcount(struct btrfs_trans_handle *trans,
3269                                      struct btrfs_root *root, u64 start,
3270                                      u64 len, u32 *refs)
3271 {
3272         int ret;
3273
3274         ret = btrfs_lookup_extent_ref(trans, root, start, len, refs);
3275         BUG_ON(ret);
3276
3277 #if 0 /* some debugging code in case we see problems here */
3278         /* if the refs count is one, it won't get increased again.  But
3279          * if the ref count is > 1, someone may be decreasing it at
3280          * the same time we are.
3281          */
3282         if (*refs != 1) {
3283                 struct extent_buffer *eb = NULL;
3284                 eb = btrfs_find_create_tree_block(root, start, len);
3285                 if (eb)
3286                         btrfs_tree_lock(eb);
3287
3288                 mutex_lock(&root->fs_info->alloc_mutex);
3289                 ret = lookup_extent_ref(NULL, root, start, len, refs);
3290                 BUG_ON(ret);
3291                 mutex_unlock(&root->fs_info->alloc_mutex);
3292
3293                 if (eb) {
3294                         btrfs_tree_unlock(eb);
3295                         free_extent_buffer(eb);
3296                 }
3297                 if (*refs == 1) {
3298                         printk(KERN_ERR "btrfs block %llu went down to one "
3299                                "during drop_snap\n", (unsigned long long)start);
3300                 }
3301
3302         }
3303 #endif
3304
3305         cond_resched();
3306         return ret;
3307 }
3308
3309 /*
3310  * this is used while deleting old snapshots, and it drops the refs
3311  * on a whole subtree starting from a level 1 node.
3312  *
3313  * The idea is to sort all the leaf pointers, and then drop the
3314  * ref on all the leaves in order.  Most of the time the leaves
3315  * will have ref cache entries, so no leaf IOs will be required to
3316  * find the extents they have references on.
3317  *
3318  * For each leaf, any references it has are also dropped in order
3319  *
3320  * This ends up dropping the references in something close to optimal
3321  * order for reading and modifying the extent allocation tree.
3322  */
3323 static noinline int drop_level_one_refs(struct btrfs_trans_handle *trans,
3324                                         struct btrfs_root *root,
3325                                         struct btrfs_path *path)
3326 {
3327         u64 bytenr;
3328         u64 root_owner;
3329         u64 root_gen;
3330         struct extent_buffer *eb = path->nodes[1];
3331         struct extent_buffer *leaf;
3332         struct btrfs_leaf_ref *ref;
3333         struct refsort *sorted = NULL;
3334         int nritems = btrfs_header_nritems(eb);
3335         int ret;
3336         int i;
3337         int refi = 0;
3338         int slot = path->slots[1];
3339         u32 blocksize = btrfs_level_size(root, 0);
3340         u32 refs;
3341
3342         if (nritems == 0)
3343                 goto out;
3344
3345         root_owner = btrfs_header_owner(eb);
3346         root_gen = btrfs_header_generation(eb);
3347         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3348
3349         /*
3350          * step one, sort all the leaf pointers so we don't scribble
3351          * randomly into the extent allocation tree
3352          */
3353         for (i = slot; i < nritems; i++) {
3354                 sorted[refi].bytenr = btrfs_node_blockptr(eb, i);
3355                 sorted[refi].slot = i;
3356                 refi++;
3357         }
3358
3359         /*
3360          * nritems won't be zero, but if we're picking up drop_snapshot
3361          * after a crash, slot might be > 0, so double check things
3362          * just in case.
3363          */
3364         if (refi == 0)
3365                 goto out;
3366
3367         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3368
3369         /*
3370          * the first loop frees everything the leaves point to
3371          */
3372         for (i = 0; i < refi; i++) {
3373                 u64 ptr_gen;
3374
3375                 bytenr = sorted[i].bytenr;
3376
3377                 /*
3378                  * check the reference count on this leaf.  If it is > 1
3379                  * we just decrement it below and don't update any
3380                  * of the refs the leaf points to.
3381                  */
3382                 ret = drop_snap_lookup_refcount(trans, root, bytenr,
3383                                                 blocksize, &refs);
3384                 BUG_ON(ret);
3385                 if (refs != 1)
3386                         continue;
3387
3388                 ptr_gen = btrfs_node_ptr_generation(eb, sorted[i].slot);
3389
3390                 /*
3391                  * the leaf only had one reference, which means the
3392                  * only thing pointing to this leaf is the snapshot
3393                  * we're deleting.  It isn't possible for the reference
3394                  * count to increase again later
3395                  *
3396                  * The reference cache is checked for the leaf,
3397                  * and if found we'll be able to drop any refs held by
3398                  * the leaf without needing to read it in.
3399                  */
3400                 ref = btrfs_lookup_leaf_ref(root, bytenr);
3401                 if (ref && ref->generation != ptr_gen) {
3402                         btrfs_free_leaf_ref(root, ref);
3403                         ref = NULL;
3404                 }
3405                 if (ref) {
3406                         ret = cache_drop_leaf_ref(trans, root, ref);
3407                         BUG_ON(ret);
3408                         btrfs_remove_leaf_ref(root, ref);
3409                         btrfs_free_leaf_ref(root, ref);
3410                 } else {
3411                         /*
3412                          * the leaf wasn't in the reference cache, so
3413                          * we have to read it.
3414                          */
3415                         leaf = read_tree_block(root, bytenr, blocksize,
3416                                                ptr_gen);
3417                         ret = btrfs_drop_leaf_ref(trans, root, leaf);
3418                         BUG_ON(ret);
3419                         free_extent_buffer(leaf);
3420                 }
3421                 atomic_inc(&root->fs_info->throttle_gen);
3422                 wake_up(&root->fs_info->transaction_throttle);
3423                 cond_resched();
3424         }
3425
3426         /*
3427          * run through the loop again to free the refs on the leaves.
3428          * This is faster than doing it in the loop above because
3429          * the leaves are likely to be clustered together.  We end up
3430          * working in nice chunks on the extent allocation tree.
3431          */
3432         for (i = 0; i < refi; i++) {
3433                 bytenr = sorted[i].bytenr;
3434                 ret = btrfs_free_extent(trans, root, bytenr,
3435                                         blocksize, eb->start,
3436                                         root_owner, root_gen, 0, 1);
3437                 BUG_ON(ret);
3438
3439                 atomic_inc(&root->fs_info->throttle_gen);
3440                 wake_up(&root->fs_info->transaction_throttle);
3441                 cond_resched();
3442         }
3443 out:
3444         kfree(sorted);
3445
3446         /*
3447          * update the path to show we've processed the entire level 1
3448          * node.  This will get saved into the root's drop_snapshot_progress
3449          * field so these drops are not repeated again if this transaction
3450          * commits.
3451          */
3452         path->slots[1] = nritems;
3453         return 0;
3454 }
3455
3456 /*
3457  * helper function for drop_snapshot, this walks down the tree dropping ref
3458  * counts as it goes.
3459  */
3460 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
3461                                    struct btrfs_root *root,
3462                                    struct btrfs_path *path, int *level)
3463 {
3464         u64 root_owner;
3465         u64 root_gen;
3466         u64 bytenr;
3467         u64 ptr_gen;
3468         struct extent_buffer *next;
3469         struct extent_buffer *cur;
3470         struct extent_buffer *parent;
3471         u32 blocksize;
3472         int ret;
3473         u32 refs;
3474
3475         WARN_ON(*level < 0);
3476         WARN_ON(*level >= BTRFS_MAX_LEVEL);
3477         ret = drop_snap_lookup_refcount(trans, root, path->nodes[*level]->start,
3478                                 path->nodes[*level]->len, &refs);
3479         BUG_ON(ret);
3480         if (refs > 1)
3481                 goto out;
3482
3483         /*
3484          * walk down to the last node level and free all the leaves
3485          */
3486         while (*level >= 0) {
3487                 WARN_ON(*level < 0);
3488                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
3489                 cur = path->nodes[*level];
3490
3491                 if (btrfs_header_level(cur) != *level)
3492                         WARN_ON(1);
3493
3494                 if (path->slots[*level] >=
3495                     btrfs_header_nritems(cur))
3496                         break;
3497
3498                 /* the new code goes down to level 1 and does all the
3499                  * leaves pointed to that node in bulk.  So, this check
3500                  * for level 0 will always be false.
3501                  *
3502                  * But, the disk format allows the drop_snapshot_progress
3503                  * field in the root to leave things in a state where
3504                  * a leaf will need cleaning up here.  If someone crashes
3505                  * with the old code and then boots with the new code,
3506                  * we might find a leaf here.
3507                  */
3508                 if (*level == 0) {
3509                         ret = btrfs_drop_leaf_ref(trans, root, cur);
3510                         BUG_ON(ret);
3511                         break;
3512                 }
3513
3514                 /*
3515                  * once we get to level one, process the whole node
3516                  * at once, including everything below it.
3517                  */
3518                 if (*level == 1) {
3519                         ret = drop_level_one_refs(trans, root, path);
3520                         BUG_ON(ret);
3521                         break;
3522                 }
3523
3524                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
3525                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
3526                 blocksize = btrfs_level_size(root, *level - 1);
3527
3528                 ret = drop_snap_lookup_refcount(trans, root, bytenr,
3529                                                 blocksize, &refs);
3530                 BUG_ON(ret);
3531
3532                 /*
3533                  * if there is more than one reference, we don't need
3534                  * to read that node to drop any references it has.  We
3535                  * just drop the ref we hold on that node and move on to the
3536                  * next slot in this level.
3537                  */
3538                 if (refs != 1) {
3539                         parent = path->nodes[*level];
3540                         root_owner = btrfs_header_owner(parent);
3541                         root_gen = btrfs_header_generation(parent);
3542                         path->slots[*level]++;
3543
3544                         ret = btrfs_free_extent(trans, root, bytenr,
3545                                                 blocksize, parent->start,
3546                                                 root_owner, root_gen,
3547                                                 *level - 1, 1);
3548                         BUG_ON(ret);
3549
3550                         atomic_inc(&root->fs_info->throttle_gen);
3551                         wake_up(&root->fs_info->transaction_throttle);
3552                         cond_resched();
3553
3554                         continue;
3555                 }
3556
3557                 /*
3558                  * we need to keep freeing things in the next level down.
3559                  * read the block and loop around to process it
3560                  */
3561                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
3562                 WARN_ON(*level <= 0);
3563                 if (path->nodes[*level-1])
3564                         free_extent_buffer(path->nodes[*level-1]);
3565                 path->nodes[*level-1] = next;
3566                 *level = btrfs_header_level(next);
3567                 path->slots[*level] = 0;
3568                 cond_resched();
3569         }
3570 out:
3571         WARN_ON(*level < 0);
3572         WARN_ON(*level >= BTRFS_MAX_LEVEL);
3573
3574         if (path->nodes[*level] == root->node) {
3575                 parent = path->nodes[*level];
3576                 bytenr = path->nodes[*level]->start;
3577         } else {
3578                 parent = path->nodes[*level + 1];
3579                 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
3580         }
3581
3582         blocksize = btrfs_level_size(root, *level);
3583         root_owner = btrfs_header_owner(parent);
3584         root_gen = btrfs_header_generation(parent);
3585
3586         /*
3587          * cleanup and free the reference on the last node
3588          * we processed
3589          */
3590         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
3591                                   parent->start, root_owner, root_gen,
3592                                   *level, 1);
3593         free_extent_buffer(path->nodes[*level]);
3594         path->nodes[*level] = NULL;
3595
3596         *level += 1;
3597         BUG_ON(ret);
3598
3599         cond_resched();
3600         return 0;
3601 }
3602
3603 /*
3604  * helper function for drop_subtree, this function is similar to
3605  * walk_down_tree. The main difference is that it checks reference
3606  * counts while tree blocks are locked.
3607  */
3608 static noinline int walk_down_subtree(struct btrfs_trans_handle *trans,
3609                                       struct btrfs_root *root,
3610                                       struct btrfs_path *path, int *level)
3611 {
3612         struct extent_buffer *next;
3613         struct extent_buffer *cur;
3614         struct extent_buffer *parent;
3615         u64 bytenr;
3616         u64 ptr_gen;
3617         u32 blocksize;
3618         u32 refs;
3619         int ret;
3620
3621         cur = path->nodes[*level];
3622         ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
3623                                       &refs);
3624         BUG_ON(ret);
3625         if (refs > 1)
3626                 goto out;
3627
3628         while (*level >= 0) {
3629                 cur = path->nodes[*level];
3630                 if (*level == 0) {
3631                         ret = btrfs_drop_leaf_ref(trans, root, cur);
3632                         BUG_ON(ret);
3633                         clean_tree_block(trans, root, cur);
3634                         break;
3635                 }
3636                 if (path->slots[*level] >= btrfs_header_nritems(cur)) {
3637                         clean_tree_block(trans, root, cur);
3638                         break;
3639                 }
3640
3641                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
3642                 blocksize = btrfs_level_size(root, *level - 1);
3643                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
3644
3645                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
3646                 btrfs_tree_lock(next);
3647                 btrfs_set_lock_blocking(next);
3648
3649                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
3650                                               &refs);
3651                 BUG_ON(ret);
3652                 if (refs > 1) {
3653                         parent = path->nodes[*level];
3654                         ret = btrfs_free_extent(trans, root, bytenr,
3655                                         blocksize, parent->start,
3656                                         btrfs_header_owner(parent),
3657                                         btrfs_header_generation(parent),
3658                                         *level - 1, 1);
3659                         BUG_ON(ret);
3660                         path->slots[*level]++;
3661                         btrfs_tree_unlock(next);
3662                         free_extent_buffer(next);
3663                         continue;
3664                 }
3665
3666                 *level = btrfs_header_level(next);
3667                 path->nodes[*level] = next;
3668                 path->slots[*level] = 0;
3669                 path->locks[*level] = 1;
3670                 cond_resched();
3671         }
3672 out:
3673         parent = path->nodes[*level + 1];
3674         bytenr = path->nodes[*level]->start;
3675         blocksize = path->nodes[*level]->len;
3676
3677         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
3678                         parent->start, btrfs_header_owner(parent),
3679                         btrfs_header_generation(parent), *level, 1);
3680         BUG_ON(ret);
3681
3682         if (path->locks[*level]) {
3683                 btrfs_tree_unlock(path->nodes[*level]);
3684                 path->locks[*level] = 0;
3685         }
3686         free_extent_buffer(path->nodes[*level]);
3687         path->nodes[*level] = NULL;
3688         *level += 1;
3689         cond_resched();
3690         return 0;
3691 }
3692
3693 /*
3694  * helper for dropping snapshots.  This walks back up the tree in the path
3695  * to find the first node higher up where we haven't yet gone through
3696  * all the slots
3697  */
3698 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
3699                                  struct btrfs_root *root,
3700                                  struct btrfs_path *path,
3701                                  int *level, int max_level)
3702 {
3703         u64 root_owner;
3704         u64 root_gen;
3705         struct btrfs_root_item *root_item = &root->root_item;
3706         int i;
3707         int slot;
3708         int ret;
3709
3710         for (i = *level; i < max_level && path->nodes[i]; i++) {
3711                 slot = path->slots[i];
3712                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
3713                         struct extent_buffer *node;
3714                         struct btrfs_disk_key disk_key;
3715
3716                         /*
3717                          * there is more work to do in this level.
3718                          * Update the drop_progress marker to reflect
3719                          * the work we've done so far, and then bump
3720                          * the slot number
3721                          */
3722                         node = path->nodes[i];
3723                         path->slots[i]++;
3724                         *level = i;
3725                         WARN_ON(*level == 0);
3726                         btrfs_node_key(node, &disk_key, path->slots[i]);
3727                         memcpy(&root_item->drop_progress,
3728                                &disk_key, sizeof(disk_key));
3729                         root_item->drop_level = i;
3730                         return 0;
3731                 } else {
3732                         struct extent_buffer *parent;
3733
3734                         /*
3735                          * this whole node is done, free our reference
3736                          * on it and go up one level
3737                          */
3738                         if (path->nodes[*level] == root->node)
3739                                 parent = path->nodes[*level];
3740                         else
3741                                 parent = path->nodes[*level + 1];
3742
3743                         root_owner = btrfs_header_owner(parent);
3744                         root_gen = btrfs_header_generation(parent);
3745
3746                         clean_tree_block(trans, root, path->nodes[*level]);
3747                         ret = btrfs_free_extent(trans, root,
3748                                                 path->nodes[*level]->start,
3749                                                 path->nodes[*level]->len,
3750                                                 parent->start, root_owner,
3751                                                 root_gen, *level, 1);
3752                         BUG_ON(ret);
3753                         if (path->locks[*level]) {
3754                                 btrfs_tree_unlock(path->nodes[*level]);
3755                                 path->locks[*level] = 0;
3756                         }
3757                         free_extent_buffer(path->nodes[*level]);
3758                         path->nodes[*level] = NULL;
3759                         *level = i + 1;
3760                 }
3761         }
3762         return 1;
3763 }
3764
3765 /*
3766  * drop the reference count on the tree rooted at 'snap'.  This traverses
3767  * the tree freeing any blocks that have a ref count of zero after being
3768  * decremented.
3769  */
3770 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
3771                         *root)
3772 {
3773         int ret = 0;
3774         int wret;
3775         int level;
3776         struct btrfs_path *path;
3777         int i;
3778         int orig_level;
3779         int update_count;
3780         struct btrfs_root_item *root_item = &root->root_item;
3781
3782         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
3783         path = btrfs_alloc_path();
3784         BUG_ON(!path);
3785
3786         level = btrfs_header_level(root->node);
3787         orig_level = level;
3788         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
3789                 path->nodes[level] = root->node;
3790                 extent_buffer_get(root->node);
3791                 path->slots[level] = 0;
3792         } else {
3793                 struct btrfs_key key;
3794                 struct btrfs_disk_key found_key;
3795                 struct extent_buffer *node;
3796
3797                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
3798                 level = root_item->drop_level;
3799                 path->lowest_level = level;
3800                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3801                 if (wret < 0) {
3802                         ret = wret;
3803                         goto out;
3804                 }
3805                 node = path->nodes[level];
3806                 btrfs_node_key(node, &found_key, path->slots[level]);
3807                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
3808                                sizeof(found_key)));
3809                 /*
3810                  * unlock our path, this is safe because only this
3811                  * function is allowed to delete this snapshot
3812                  */
3813                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3814                         if (path->nodes[i] && path->locks[i]) {
3815                                 path->locks[i] = 0;
3816                                 btrfs_tree_unlock(path->nodes[i]);
3817                         }
3818                 }
3819         }
3820         while (1) {
3821                 unsigned long update;
3822                 wret = walk_down_tree(trans, root, path, &level);
3823                 if (wret > 0)
3824                         break;
3825                 if (wret < 0)
3826                         ret = wret;
3827
3828                 wret = walk_up_tree(trans, root, path, &level,
3829                                     BTRFS_MAX_LEVEL);
3830                 if (wret > 0)
3831                         break;
3832                 if (wret < 0)
3833                         ret = wret;
3834                 if (trans->transaction->in_commit ||
3835                     trans->transaction->delayed_refs.flushing) {
3836                         ret = -EAGAIN;
3837                         break;
3838                 }
3839                 atomic_inc(&root->fs_info->throttle_gen);
3840                 wake_up(&root->fs_info->transaction_throttle);
3841                 for (update_count = 0; update_count < 16; update_count++) {
3842                         update = trans->delayed_ref_updates;
3843                         trans->delayed_ref_updates = 0;
3844                         if (update)
3845                                 btrfs_run_delayed_refs(trans, root, update);
3846                         else
3847                                 break;
3848                 }
3849         }
3850         for (i = 0; i <= orig_level; i++) {
3851                 if (path->nodes[i]) {
3852                         free_extent_buffer(path->nodes[i]);
3853                         path->nodes[i] = NULL;
3854                 }
3855         }
3856 out:
3857         btrfs_free_path(path);
3858         return ret;
3859 }
3860
3861 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
3862                         struct btrfs_root *root,
3863                         struct extent_buffer *node,
3864                         struct extent_buffer *parent)
3865 {
3866         struct btrfs_path *path;
3867         int level;
3868         int parent_level;
3869         int ret = 0;
3870         int wret;
3871
3872         path = btrfs_alloc_path();
3873         BUG_ON(!path);
3874
3875         btrfs_assert_tree_locked(parent);
3876         parent_level = btrfs_header_level(parent);
3877         extent_buffer_get(parent);
3878         path->nodes[parent_level] = parent;
3879         path->slots[parent_level] = btrfs_header_nritems(parent);
3880
3881         btrfs_assert_tree_locked(node);
3882         level = btrfs_header_level(node);
3883         extent_buffer_get(node);
3884         path->nodes[level] = node;
3885         path->slots[level] = 0;
3886
3887         while (1) {
3888                 wret = walk_down_subtree(trans, root, path, &level);
3889                 if (wret < 0)
3890                         ret = wret;
3891                 if (wret != 0)
3892                         break;
3893
3894                 wret = walk_up_tree(trans, root, path, &level, parent_level);
3895                 if (wret < 0)
3896                         ret = wret;
3897                 if (wret != 0)
3898                         break;
3899         }
3900
3901         btrfs_free_path(path);
3902         return ret;
3903 }
3904
3905 static unsigned long calc_ra(unsigned long start, unsigned long last,
3906                              unsigned long nr)
3907 {
3908         return min(last, start + nr - 1);
3909 }
3910
3911 static noinline int relocate_inode_pages(struct inode *inode, u64 start,
3912                                          u64 len)
3913 {
3914         u64 page_start;
3915         u64 page_end;
3916         unsigned long first_index;
3917         unsigned long last_index;
3918         unsigned long i;
3919         struct page *page;
3920         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3921         struct file_ra_state *ra;
3922         struct btrfs_ordered_extent *ordered;
3923         unsigned int total_read = 0;
3924         unsigned int total_dirty = 0;
3925         int ret = 0;
3926
3927         ra = kzalloc(sizeof(*ra), GFP_NOFS);
3928
3929         mutex_lock(&inode->i_mutex);
3930         first_index = start >> PAGE_CACHE_SHIFT;
3931         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
3932
3933         /* make sure the dirty trick played by the caller work */
3934         ret = invalidate_inode_pages2_range(inode->i_mapping,
3935                                             first_index, last_index);
3936         if (ret)
3937                 goto out_unlock;
3938
3939         file_ra_state_init(ra, inode->i_mapping);
3940
3941         for (i = first_index ; i <= last_index; i++) {
3942                 if (total_read % ra->ra_pages == 0) {
3943                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
3944                                        calc_ra(i, last_index, ra->ra_pages));
3945                 }
3946                 total_read++;
3947 again:
3948                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
3949                         BUG_ON(1);
3950                 page = grab_cache_page(inode->i_mapping, i);
3951                 if (!page) {
3952                         ret = -ENOMEM;
3953                         goto out_unlock;
3954                 }
3955                 if (!PageUptodate(page)) {
3956                         btrfs_readpage(NULL, page);
3957                         lock_page(page);
3958                         if (!PageUptodate(page)) {
3959                                 unlock_page(page);
3960                                 page_cache_release(page);
3961                                 ret = -EIO;
3962                                 goto out_unlock;
3963                         }
3964                 }
3965                 wait_on_page_writeback(page);
3966
3967                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
3968                 page_end = page_start + PAGE_CACHE_SIZE - 1;
3969                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3970
3971                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
3972                 if (ordered) {
3973                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3974                         unlock_page(page);
3975                         page_cache_release(page);
3976                         btrfs_start_ordered_extent(inode, ordered, 1);
3977                         btrfs_put_ordered_extent(ordered);
3978                         goto again;
3979                 }
3980                 set_page_extent_mapped(page);
3981
3982                 if (i == first_index)
3983                         set_extent_bits(io_tree, page_start, page_end,
3984                                         EXTENT_BOUNDARY, GFP_NOFS);
3985                 btrfs_set_extent_delalloc(inode, page_start, page_end);
3986
3987                 set_page_dirty(page);
3988                 total_dirty++;
3989
3990                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3991                 unlock_page(page);
3992                 page_cache_release(page);
3993         }
3994
3995 out_unlock:
3996         kfree(ra);
3997         mutex_unlock(&inode->i_mutex);
3998         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
3999         return ret;
4000 }
4001
4002 static noinline int relocate_data_extent(struct inode *reloc_inode,
4003                                          struct btrfs_key *extent_key,
4004                                          u64 offset)
4005 {
4006         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4007         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
4008         struct extent_map *em;
4009         u64 start = extent_key->objectid - offset;
4010         u64 end = start + extent_key->offset - 1;
4011
4012         em = alloc_extent_map(GFP_NOFS);
4013         BUG_ON(!em || IS_ERR(em));
4014
4015         em->start = start;
4016         em->len = extent_key->offset;
4017         em->block_len = extent_key->offset;
4018         em->block_start = extent_key->objectid;
4019         em->bdev = root->fs_info->fs_devices->latest_bdev;
4020         set_bit(EXTENT_FLAG_PINNED, &em->flags);
4021
4022         /* setup extent map to cheat btrfs_readpage */
4023         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4024         while (1) {
4025                 int ret;
4026                 spin_lock(&em_tree->lock);
4027                 ret = add_extent_mapping(em_tree, em);
4028                 spin_unlock(&em_tree->lock);
4029                 if (ret != -EEXIST) {
4030                         free_extent_map(em);
4031                         break;
4032                 }
4033                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
4034         }
4035         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4036
4037         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
4038 }
4039
4040 struct btrfs_ref_path {
4041         u64 extent_start;
4042         u64 nodes[BTRFS_MAX_LEVEL];
4043         u64 root_objectid;
4044         u64 root_generation;
4045         u64 owner_objectid;
4046         u32 num_refs;
4047         int lowest_level;
4048         int current_level;
4049         int shared_level;
4050
4051         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
4052         u64 new_nodes[BTRFS_MAX_LEVEL];
4053 };
4054
4055 struct disk_extent {
4056         u64 ram_bytes;
4057         u64 disk_bytenr;
4058         u64 disk_num_bytes;
4059         u64 offset;
4060         u64 num_bytes;
4061         u8 compression;
4062         u8 encryption;
4063         u16 other_encoding;
4064 };
4065
4066 static int is_cowonly_root(u64 root_objectid)
4067 {
4068         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
4069             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
4070             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
4071             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
4072             root_objectid == BTRFS_TREE_LOG_OBJECTID ||
4073             root_objectid == BTRFS_CSUM_TREE_OBJECTID)
4074                 return 1;
4075         return 0;
4076 }
4077
4078 static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
4079                                     struct btrfs_root *extent_root,
4080                                     struct btrfs_ref_path *ref_path,
4081                                     int first_time)
4082 {
4083         struct extent_buffer *leaf;
4084         struct btrfs_path *path;
4085         struct btrfs_extent_ref *ref;
4086         struct btrfs_key key;
4087         struct btrfs_key found_key;
4088         u64 bytenr;
4089         u32 nritems;
4090         int level;
4091         int ret = 1;
4092
4093         path = btrfs_alloc_path();
4094         if (!path)
4095                 return -ENOMEM;
4096
4097         if (first_time) {
4098                 ref_path->lowest_level = -1;
4099                 ref_path->current_level = -1;
4100                 ref_path->shared_level = -1;
4101                 goto walk_up;
4102         }
4103 walk_down:
4104         level = ref_path->current_level - 1;
4105         while (level >= -1) {
4106                 u64 parent;
4107                 if (level < ref_path->lowest_level)
4108                         break;
4109
4110                 if (level >= 0)
4111                         bytenr = ref_path->nodes[level];
4112                 else
4113                         bytenr = ref_path->extent_start;
4114                 BUG_ON(bytenr == 0);
4115
4116                 parent = ref_path->nodes[level + 1];
4117                 ref_path->nodes[level + 1] = 0;
4118                 ref_path->current_level = level;
4119                 BUG_ON(parent == 0);
4120
4121                 key.objectid = bytenr;
4122                 key.offset = parent + 1;
4123                 key.type = BTRFS_EXTENT_REF_KEY;
4124
4125                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4126                 if (ret < 0)
4127                         goto out;
4128                 BUG_ON(ret == 0);
4129
4130                 leaf = path->nodes[0];
4131                 nritems = btrfs_header_nritems(leaf);
4132                 if (path->slots[0] >= nritems) {
4133                         ret = btrfs_next_leaf(extent_root, path);
4134                         if (ret < 0)
4135                                 goto out;
4136                         if (ret > 0)
4137                                 goto next;
4138                         leaf = path->nodes[0];
4139                 }
4140
4141                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4142                 if (found_key.objectid == bytenr &&
4143                     found_key.type == BTRFS_EXTENT_REF_KEY) {
4144                         if (level < ref_path->shared_level)
4145                                 ref_path->shared_level = level;
4146                         goto found;
4147                 }
4148 next:
4149                 level--;
4150                 btrfs_release_path(extent_root, path);
4151                 cond_resched();
4152         }
4153         /* reached lowest level */
4154         ret = 1;
4155         goto out;
4156 walk_up:
4157         level = ref_path->current_level;
4158         while (level < BTRFS_MAX_LEVEL - 1) {
4159                 u64 ref_objectid;
4160
4161                 if (level >= 0)
4162                         bytenr = ref_path->nodes[level];
4163                 else
4164                         bytenr = ref_path->extent_start;
4165
4166                 BUG_ON(bytenr == 0);
4167
4168                 key.objectid = bytenr;
4169                 key.offset = 0;
4170                 key.type = BTRFS_EXTENT_REF_KEY;
4171
4172                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4173                 if (ret < 0)
4174                         goto out;
4175
4176                 leaf = path->nodes[0];
4177                 nritems = btrfs_header_nritems(leaf);
4178                 if (path->slots[0] >= nritems) {
4179                         ret = btrfs_next_leaf(extent_root, path);
4180                         if (ret < 0)
4181                                 goto out;
4182                         if (ret > 0) {
4183                                 /* the extent was freed by someone */
4184                                 if (ref_path->lowest_level == level)
4185                                         goto out;
4186                                 btrfs_release_path(extent_root, path);
4187                                 goto walk_down;
4188                         }
4189                         leaf = path->nodes[0];
4190                 }
4191
4192                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4193                 if (found_key.objectid != bytenr ||
4194                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
4195                         /* the extent was freed by someone */
4196                         if (ref_path->lowest_level == level) {
4197                                 ret = 1;
4198                                 goto out;
4199                         }
4200                         btrfs_release_path(extent_root, path);
4201                         goto walk_down;
4202                 }
4203 found:
4204                 ref = btrfs_item_ptr(leaf, path->slots[0],
4205                                 struct btrfs_extent_ref);
4206                 ref_objectid = btrfs_ref_objectid(leaf, ref);
4207                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4208                         if (first_time) {
4209                                 level = (int)ref_objectid;
4210                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
4211                                 ref_path->lowest_level = level;
4212                                 ref_path->current_level = level;
4213                                 ref_path->nodes[level] = bytenr;
4214                         } else {
4215                                 WARN_ON(ref_objectid != level);
4216                         }
4217                 } else {
4218                         WARN_ON(level != -1);
4219                 }
4220                 first_time = 0;
4221
4222                 if (ref_path->lowest_level == level) {
4223                         ref_path->owner_objectid = ref_objectid;
4224                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
4225                 }
4226
4227                 /*
4228                  * the block is tree root or the block isn't in reference
4229                  * counted tree.
4230                  */
4231                 if (found_key.objectid == found_key.offset ||
4232                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
4233                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4234                         ref_path->root_generation =
4235                                 btrfs_ref_generation(leaf, ref);
4236                         if (level < 0) {
4237                                 /* special reference from the tree log */
4238                                 ref_path->nodes[0] = found_key.offset;
4239                                 ref_path->current_level = 0;
4240                         }
4241                         ret = 0;
4242                         goto out;
4243                 }
4244
4245                 level++;
4246                 BUG_ON(ref_path->nodes[level] != 0);
4247                 ref_path->nodes[level] = found_key.offset;
4248                 ref_path->current_level = level;
4249
4250                 /*
4251                  * the reference was created in the running transaction,
4252                  * no need to continue walking up.
4253                  */
4254                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
4255                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4256                         ref_path->root_generation =
4257                                 btrfs_ref_generation(leaf, ref);
4258                         ret = 0;
4259                         goto out;
4260                 }
4261
4262                 btrfs_release_path(extent_root, path);
4263                 cond_resched();
4264         }
4265         /* reached max tree level, but no tree root found. */
4266         BUG();
4267 out:
4268         btrfs_free_path(path);
4269         return ret;
4270 }
4271
4272 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
4273                                 struct btrfs_root *extent_root,
4274                                 struct btrfs_ref_path *ref_path,
4275                                 u64 extent_start)
4276 {
4277         memset(ref_path, 0, sizeof(*ref_path));
4278         ref_path->extent_start = extent_start;
4279
4280         return __next_ref_path(trans, extent_root, ref_path, 1);
4281 }
4282
4283 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
4284                                struct btrfs_root *extent_root,
4285                                struct btrfs_ref_path *ref_path)
4286 {
4287         return __next_ref_path(trans, extent_root, ref_path, 0);
4288 }
4289
4290 static noinline int get_new_locations(struct inode *reloc_inode,
4291                                       struct btrfs_key *extent_key,
4292                                       u64 offset, int no_fragment,
4293                                       struct disk_extent **extents,
4294                                       int *nr_extents)
4295 {
4296         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4297         struct btrfs_path *path;
4298         struct btrfs_file_extent_item *fi;
4299         struct extent_buffer *leaf;
4300         struct disk_extent *exts = *extents;
4301         struct btrfs_key found_key;
4302         u64 cur_pos;
4303         u64 last_byte;
4304         u32 nritems;
4305         int nr = 0;
4306         int max = *nr_extents;
4307         int ret;
4308
4309         WARN_ON(!no_fragment && *extents);
4310         if (!exts) {
4311                 max = 1;
4312                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
4313                 if (!exts)
4314                         return -ENOMEM;
4315         }
4316
4317         path = btrfs_alloc_path();
4318         BUG_ON(!path);
4319
4320         cur_pos = extent_key->objectid - offset;
4321         last_byte = extent_key->objectid + extent_key->offset;
4322         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
4323                                        cur_pos, 0);
4324         if (ret < 0)
4325                 goto out;
4326         if (ret > 0) {
4327                 ret = -ENOENT;
4328                 goto out;
4329         }
4330
4331         while (1) {
4332                 leaf = path->nodes[0];
4333                 nritems = btrfs_header_nritems(leaf);
4334                 if (path->slots[0] >= nritems) {
4335                         ret = btrfs_next_leaf(root, path);
4336                         if (ret < 0)
4337                                 goto out;
4338                         if (ret > 0)
4339                                 break;
4340                         leaf = path->nodes[0];
4341                 }
4342
4343                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4344                 if (found_key.offset != cur_pos ||
4345                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
4346                     found_key.objectid != reloc_inode->i_ino)
4347                         break;
4348
4349                 fi = btrfs_item_ptr(leaf, path->slots[0],
4350                                     struct btrfs_file_extent_item);
4351                 if (btrfs_file_extent_type(leaf, fi) !=
4352                     BTRFS_FILE_EXTENT_REG ||
4353                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4354                         break;
4355
4356                 if (nr == max) {
4357                         struct disk_extent *old = exts;
4358                         max *= 2;
4359                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
4360                         memcpy(exts, old, sizeof(*exts) * nr);
4361                         if (old != *extents)
4362                                 kfree(old);
4363                 }
4364
4365                 exts[nr].disk_bytenr =
4366                         btrfs_file_extent_disk_bytenr(leaf, fi);
4367                 exts[nr].disk_num_bytes =
4368                         btrfs_file_extent_disk_num_bytes(leaf, fi);
4369                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
4370                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4371                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
4372                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
4373                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
4374                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
4375                                                                            fi);
4376                 BUG_ON(exts[nr].offset > 0);
4377                 BUG_ON(exts[nr].compression || exts[nr].encryption);
4378                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
4379
4380                 cur_pos += exts[nr].num_bytes;
4381                 nr++;
4382
4383                 if (cur_pos + offset >= last_byte)
4384                         break;
4385
4386                 if (no_fragment) {
4387                         ret = 1;
4388                         goto out;
4389                 }
4390                 path->slots[0]++;
4391         }
4392
4393         BUG_ON(cur_pos + offset > last_byte);
4394         if (cur_pos + offset < last_byte) {
4395                 ret = -ENOENT;
4396                 goto out;
4397         }
4398         ret = 0;
4399 out:
4400         btrfs_free_path(path);
4401         if (ret) {
4402                 if (exts != *extents)
4403                         kfree(exts);
4404         } else {
4405                 *extents = exts;
4406                 *nr_extents = nr;
4407         }
4408         return ret;
4409 }
4410
4411 static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
4412                                         struct btrfs_root *root,
4413                                         struct btrfs_path *path,
4414                                         struct btrfs_key *extent_key,
4415                                         struct btrfs_key *leaf_key,
4416                                         struct btrfs_ref_path *ref_path,
4417                                         struct disk_extent *new_extents,
4418                                         int nr_extents)
4419 {
4420         struct extent_buffer *leaf;
4421         struct btrfs_file_extent_item *fi;
4422         struct inode *inode = NULL;
4423         struct btrfs_key key;
4424         u64 lock_start = 0;
4425         u64 lock_end = 0;
4426         u64 num_bytes;
4427         u64 ext_offset;
4428         u64 search_end = (u64)-1;
4429         u32 nritems;
4430         int nr_scaned = 0;
4431         int extent_locked = 0;
4432         int extent_type;
4433         int ret;
4434
4435         memcpy(&key, leaf_key, sizeof(key));
4436         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
4437                 if (key.objectid < ref_path->owner_objectid ||
4438                     (key.objectid == ref_path->owner_objectid &&
4439                      key.type < BTRFS_EXTENT_DATA_KEY)) {
4440                         key.objectid = ref_path->owner_objectid;
4441                         key.type = BTRFS_EXTENT_DATA_KEY;
4442                         key.offset = 0;
4443                 }
4444         }
4445
4446         while (1) {
4447                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4448                 if (ret < 0)
4449                         goto out;
4450
4451                 leaf = path->nodes[0];
4452                 nritems = btrfs_header_nritems(leaf);
4453 next:
4454                 if (extent_locked && ret > 0) {
4455                         /*
4456                          * the file extent item was modified by someone
4457                          * before the extent got locked.
4458                          */
4459                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4460                                       lock_end, GFP_NOFS);
4461                         extent_locked = 0;
4462                 }
4463
4464                 if (path->slots[0] >= nritems) {
4465                         if (++nr_scaned > 2)
4466                                 break;
4467
4468                         BUG_ON(extent_locked);
4469                         ret = btrfs_next_leaf(root, path);
4470                         if (ret < 0)
4471                                 goto out;
4472                         if (ret > 0)
4473                                 break;
4474                         leaf = path->nodes[0];
4475                         nritems = btrfs_header_nritems(leaf);
4476                 }
4477
4478                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4479
4480                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
4481                         if ((key.objectid > ref_path->owner_objectid) ||
4482                             (key.objectid == ref_path->owner_objectid &&
4483                              key.type > BTRFS_EXTENT_DATA_KEY) ||
4484                             key.offset >= search_end)
4485                                 break;
4486                 }
4487
4488                 if (inode && key.objectid != inode->i_ino) {
4489                         BUG_ON(extent_locked);
4490                         btrfs_release_path(root, path);
4491                         mutex_unlock(&inode->i_mutex);
4492                         iput(inode);
4493                         inode = NULL;
4494                         continue;
4495                 }
4496
4497                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
4498                         path->slots[0]++;
4499                         ret = 1;
4500                         goto next;
4501                 }
4502                 fi = btrfs_item_ptr(leaf, path->slots[0],
4503                                     struct btrfs_file_extent_item);
4504                 extent_type = btrfs_file_extent_type(leaf, fi);
4505                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
4506                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
4507                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
4508                      extent_key->objectid)) {
4509                         path->slots[0]++;
4510                         ret = 1;
4511                         goto next;
4512                 }
4513
4514                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4515                 ext_offset = btrfs_file_extent_offset(leaf, fi);
4516
4517                 if (search_end == (u64)-1) {
4518                         search_end = key.offset - ext_offset +
4519                                 btrfs_file_extent_ram_bytes(leaf, fi);
4520                 }
4521
4522                 if (!extent_locked) {
4523                         lock_start = key.offset;
4524                         lock_end = lock_start + num_bytes - 1;
4525                 } else {
4526                         if (lock_start > key.offset ||
4527                             lock_end + 1 < key.offset + num_bytes) {
4528                                 unlock_extent(&BTRFS_I(inode)->io_tree,
4529                                               lock_start, lock_end, GFP_NOFS);
4530                                 extent_locked = 0;
4531                         }
4532                 }
4533
4534                 if (!inode) {
4535                         btrfs_release_path(root, path);
4536
4537                         inode = btrfs_iget_locked(root->fs_info->sb,
4538                                                   key.objectid, root);
4539                         if (inode->i_state & I_NEW) {
4540                                 BTRFS_I(inode)->root = root;
4541                                 BTRFS_I(inode)->location.objectid =
4542                                         key.objectid;
4543                                 BTRFS_I(inode)->location.type =
4544                                         BTRFS_INODE_ITEM_KEY;
4545                                 BTRFS_I(inode)->location.offset = 0;
4546                                 btrfs_read_locked_inode(inode);
4547                                 unlock_new_inode(inode);
4548                         }
4549                         /*
4550                          * some code call btrfs_commit_transaction while
4551                          * holding the i_mutex, so we can't use mutex_lock
4552                          * here.
4553                          */
4554                         if (is_bad_inode(inode) ||
4555                             !mutex_trylock(&inode->i_mutex)) {
4556                                 iput(inode);
4557                                 inode = NULL;
4558                                 key.offset = (u64)-1;
4559                                 goto skip;
4560                         }
4561                 }
4562
4563                 if (!extent_locked) {
4564                         struct btrfs_ordered_extent *ordered;
4565
4566                         btrfs_release_path(root, path);
4567
4568                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4569                                     lock_end, GFP_NOFS);
4570                         ordered = btrfs_lookup_first_ordered_extent(inode,
4571                                                                     lock_end);
4572                         if (ordered &&
4573                             ordered->file_offset <= lock_end &&
4574                             ordered->file_offset + ordered->len > lock_start) {
4575                                 unlock_extent(&BTRFS_I(inode)->io_tree,
4576                                               lock_start, lock_end, GFP_NOFS);
4577                                 btrfs_start_ordered_extent(inode, ordered, 1);
4578                                 btrfs_put_ordered_extent(ordered);
4579                                 key.offset += num_bytes;
4580                                 goto skip;
4581                         }
4582                         if (ordered)
4583                                 btrfs_put_ordered_extent(ordered);
4584
4585                         extent_locked = 1;
4586                         continue;
4587                 }
4588
4589                 if (nr_extents == 1) {
4590                         /* update extent pointer in place */
4591                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
4592                                                 new_extents[0].disk_bytenr);
4593                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4594                                                 new_extents[0].disk_num_bytes);
4595                         btrfs_mark_buffer_dirty(leaf);
4596
4597                         btrfs_drop_extent_cache(inode, key.offset,
4598                                                 key.offset + num_bytes - 1, 0);
4599
4600                         ret = btrfs_inc_extent_ref(trans, root,
4601                                                 new_extents[0].disk_bytenr,
4602                                                 new_extents[0].disk_num_bytes,
4603                                                 leaf->start,
4604                                                 root->root_key.objectid,
4605                                                 trans->transid,
4606                                                 key.objectid);
4607                         BUG_ON(ret);
4608
4609                         ret = btrfs_free_extent(trans, root,
4610                                                 extent_key->objectid,
4611                                                 extent_key->offset,
4612                                                 leaf->start,
4613                                                 btrfs_header_owner(leaf),
4614                                                 btrfs_header_generation(leaf),
4615                                                 key.objectid, 0);
4616                         BUG_ON(ret);
4617
4618                         btrfs_release_path(root, path);
4619                         key.offset += num_bytes;
4620                 } else {
4621                         BUG_ON(1);
4622 #if 0
4623                         u64 alloc_hint;
4624                         u64 extent_len;
4625                         int i;
4626                         /*
4627                          * drop old extent pointer at first, then insert the
4628                          * new pointers one bye one
4629                          */
4630                         btrfs_release_path(root, path);
4631                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
4632                                                  key.offset + num_bytes,
4633                                                  key.offset, &alloc_hint);
4634                         BUG_ON(ret);
4635
4636                         for (i = 0; i < nr_extents; i++) {
4637                                 if (ext_offset >= new_extents[i].num_bytes) {
4638                                         ext_offset -= new_extents[i].num_bytes;
4639                                         continue;
4640                                 }
4641                                 extent_len = min(new_extents[i].num_bytes -
4642                                                  ext_offset, num_bytes);
4643
4644                                 ret = btrfs_insert_empty_item(trans, root,
4645                                                               path, &key,
4646                                                               sizeof(*fi));
4647                                 BUG_ON(ret);
4648
4649                                 leaf = path->nodes[0];
4650                                 fi = btrfs_item_ptr(leaf, path->slots[0],
4651                                                 struct btrfs_file_extent_item);
4652                                 btrfs_set_file_extent_generation(leaf, fi,
4653                                                         trans->transid);
4654                                 btrfs_set_file_extent_type(leaf, fi,
4655                                                         BTRFS_FILE_EXTENT_REG);
4656                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4657                                                 new_extents[i].disk_bytenr);
4658                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4659                                                 new_extents[i].disk_num_bytes);
4660                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
4661                                                 new_extents[i].ram_bytes);
4662
4663                                 btrfs_set_file_extent_compression(leaf, fi,
4664                                                 new_extents[i].compression);
4665                                 btrfs_set_file_extent_encryption(leaf, fi,
4666                                                 new_extents[i].encryption);
4667                                 btrfs_set_file_extent_other_encoding(leaf, fi,
4668                                                 new_extents[i].other_encoding);
4669
4670                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4671                                                         extent_len);
4672                                 ext_offset += new_extents[i].offset;
4673                                 btrfs_set_file_extent_offset(leaf, fi,
4674                                                         ext_offset);
4675                                 btrfs_mark_buffer_dirty(leaf);
4676
4677                                 btrfs_drop_extent_cache(inode, key.offset,
4678                                                 key.offset + extent_len - 1, 0);
4679
4680                                 ret = btrfs_inc_extent_ref(trans, root,
4681                                                 new_extents[i].disk_bytenr,
4682                                                 new_extents[i].disk_num_bytes,
4683                                                 leaf->start,
4684                                                 root->root_key.objectid,
4685                                                 trans->transid, key.objectid);
4686                                 BUG_ON(ret);
4687                                 btrfs_release_path(root, path);
4688
4689                                 inode_add_bytes(inode, extent_len);
4690
4691                                 ext_offset = 0;
4692                                 num_bytes -= extent_len;
4693                                 key.offset += extent_len;
4694
4695                                 if (num_bytes == 0)
4696                                         break;
4697                         }
4698                         BUG_ON(i >= nr_extents);
4699 #endif
4700                 }
4701
4702                 if (extent_locked) {
4703                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4704                                       lock_end, GFP_NOFS);
4705                         extent_locked = 0;
4706                 }
4707 skip:
4708                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
4709                     key.offset >= search_end)
4710                         break;
4711
4712                 cond_resched();
4713         }
4714         ret = 0;
4715 out:
4716         btrfs_release_path(root, path);
4717         if (inode) {
4718                 mutex_unlock(&inode->i_mutex);
4719                 if (extent_locked) {
4720                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4721                                       lock_end, GFP_NOFS);
4722                 }
4723                 iput(inode);
4724         }
4725         return ret;
4726 }
4727
4728 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
4729                                struct btrfs_root *root,
4730                                struct extent_buffer *buf, u64 orig_start)
4731 {
4732         int level;
4733         int ret;
4734
4735         BUG_ON(btrfs_header_generation(buf) != trans->transid);
4736         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
4737
4738         level = btrfs_header_level(buf);
4739         if (level == 0) {
4740                 struct btrfs_leaf_ref *ref;
4741                 struct btrfs_leaf_ref *orig_ref;
4742
4743                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
4744                 if (!orig_ref)
4745                         return -ENOENT;
4746
4747                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
4748                 if (!ref) {
4749                         btrfs_free_leaf_ref(root, orig_ref);
4750                         return -ENOMEM;
4751                 }
4752
4753                 ref->nritems = orig_ref->nritems;
4754                 memcpy(ref->extents, orig_ref->extents,
4755                         sizeof(ref->extents[0]) * ref->nritems);
4756
4757                 btrfs_free_leaf_ref(root, orig_ref);
4758
4759                 ref->root_gen = trans->transid;
4760                 ref->bytenr = buf->start;
4761                 ref->owner = btrfs_header_owner(buf);
4762                 ref->generation = btrfs_header_generation(buf);
4763
4764                 ret = btrfs_add_leaf_ref(root, ref, 0);
4765                 WARN_ON(ret);
4766                 btrfs_free_leaf_ref(root, ref);
4767         }
4768         return 0;
4769 }
4770
4771 static noinline int invalidate_extent_cache(struct btrfs_root *root,
4772                                         struct extent_buffer *leaf,
4773                                         struct btrfs_block_group_cache *group,
4774                                         struct btrfs_root *target_root)
4775 {
4776         struct btrfs_key key;
4777         struct inode *inode = NULL;
4778         struct btrfs_file_extent_item *fi;
4779         u64 num_bytes;
4780         u64 skip_objectid = 0;
4781         u32 nritems;
4782         u32 i;
4783
4784         nritems = btrfs_header_nritems(leaf);
4785         for (i = 0; i < nritems; i++) {
4786                 btrfs_item_key_to_cpu(leaf, &key, i);
4787                 if (key.objectid == skip_objectid ||
4788                     key.type != BTRFS_EXTENT_DATA_KEY)
4789                         continue;
4790                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4791                 if (btrfs_file_extent_type(leaf, fi) ==
4792                     BTRFS_FILE_EXTENT_INLINE)
4793                         continue;
4794                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4795                         continue;
4796                 if (!inode || inode->i_ino != key.objectid) {
4797                         iput(inode);
4798                         inode = btrfs_ilookup(target_root->fs_info->sb,
4799                                               key.objectid, target_root, 1);
4800                 }
4801                 if (!inode) {
4802                         skip_objectid = key.objectid;
4803                         continue;
4804                 }
4805                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4806
4807                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4808                             key.offset + num_bytes - 1, GFP_NOFS);
4809                 btrfs_drop_extent_cache(inode, key.offset,
4810                                         key.offset + num_bytes - 1, 1);
4811                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4812                               key.offset + num_bytes - 1, GFP_NOFS);
4813                 cond_resched();
4814         }
4815         iput(inode);
4816         return 0;
4817 }
4818
4819 static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
4820                                         struct btrfs_root *root,
4821                                         struct extent_buffer *leaf,
4822                                         struct btrfs_block_group_cache *group,
4823                                         struct inode *reloc_inode)
4824 {
4825         struct btrfs_key key;
4826         struct btrfs_key extent_key;
4827         struct btrfs_file_extent_item *fi;
4828         struct btrfs_leaf_ref *ref;
4829         struct disk_extent *new_extent;
4830         u64 bytenr;
4831         u64 num_bytes;
4832         u32 nritems;
4833         u32 i;
4834         int ext_index;
4835         int nr_extent;
4836         int ret;
4837
4838         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
4839         BUG_ON(!new_extent);
4840
4841         ref = btrfs_lookup_leaf_ref(root, leaf->start);
4842         BUG_ON(!ref);
4843
4844         ext_index = -1;
4845         nritems = btrfs_header_nritems(leaf);
4846         for (i = 0; i < nritems; i++) {
4847                 btrfs_item_key_to_cpu(leaf, &key, i);
4848                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
4849                         continue;
4850                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4851                 if (btrfs_file_extent_type(leaf, fi) ==
4852                     BTRFS_FILE_EXTENT_INLINE)
4853                         continue;
4854                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
4855                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
4856                 if (bytenr == 0)
4857                         continue;
4858
4859                 ext_index++;
4860                 if (bytenr >= group->key.objectid + group->key.offset ||
4861                     bytenr + num_bytes <= group->key.objectid)
4862                         continue;
4863
4864                 extent_key.objectid = bytenr;
4865                 extent_key.offset = num_bytes;
4866                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4867                 nr_extent = 1;
4868                 ret = get_new_locations(reloc_inode, &extent_key,
4869                                         group->key.objectid, 1,
4870                                         &new_extent, &nr_extent);
4871                 if (ret > 0)
4872                         continue;
4873                 BUG_ON(ret < 0);
4874
4875                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
4876                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
4877                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
4878                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
4879
4880                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4881                                                 new_extent->disk_bytenr);
4882                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4883                                                 new_extent->disk_num_bytes);
4884                 btrfs_mark_buffer_dirty(leaf);
4885
4886                 ret = btrfs_inc_extent_ref(trans, root,
4887                                         new_extent->disk_bytenr,
4888                                         new_extent->disk_num_bytes,
4889                                         leaf->start,
4890                                         root->root_key.objectid,
4891                                         trans->transid, key.objectid);
4892                 BUG_ON(ret);
4893
4894                 ret = btrfs_free_extent(trans, root,
4895                                         bytenr, num_bytes, leaf->start,
4896                                         btrfs_header_owner(leaf),
4897                                         btrfs_header_generation(leaf),
4898                                         key.objectid, 0);
4899                 BUG_ON(ret);
4900                 cond_resched();
4901         }
4902         kfree(new_extent);
4903         BUG_ON(ext_index + 1 != ref->nritems);
4904         btrfs_free_leaf_ref(root, ref);
4905         return 0;
4906 }
4907
4908 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
4909                           struct btrfs_root *root)
4910 {
4911         struct btrfs_root *reloc_root;
4912         int ret;
4913
4914         if (root->reloc_root) {
4915                 reloc_root = root->reloc_root;
4916                 root->reloc_root = NULL;
4917                 list_add(&reloc_root->dead_list,
4918                          &root->fs_info->dead_reloc_roots);
4919
4920                 btrfs_set_root_bytenr(&reloc_root->root_item,
4921                                       reloc_root->node->start);
4922                 btrfs_set_root_level(&root->root_item,
4923                                      btrfs_header_level(reloc_root->node));
4924                 memset(&reloc_root->root_item.drop_progress, 0,
4925                         sizeof(struct btrfs_disk_key));
4926                 reloc_root->root_item.drop_level = 0;
4927
4928                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4929                                         &reloc_root->root_key,
4930                                         &reloc_root->root_item);
4931                 BUG_ON(ret);
4932         }
4933         return 0;
4934 }
4935
4936 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
4937 {
4938         struct btrfs_trans_handle *trans;
4939         struct btrfs_root *reloc_root;
4940         struct btrfs_root *prev_root = NULL;
4941         struct list_head dead_roots;
4942         int ret;
4943         unsigned long nr;
4944
4945         INIT_LIST_HEAD(&dead_roots);
4946         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
4947
4948         while (!list_empty(&dead_roots)) {
4949                 reloc_root = list_entry(dead_roots.prev,
4950                                         struct btrfs_root, dead_list);
4951                 list_del_init(&reloc_root->dead_list);
4952
4953                 BUG_ON(reloc_root->commit_root != NULL);
4954                 while (1) {
4955                         trans = btrfs_join_transaction(root, 1);
4956                         BUG_ON(!trans);
4957
4958                         mutex_lock(&root->fs_info->drop_mutex);
4959                         ret = btrfs_drop_snapshot(trans, reloc_root);
4960                         if (ret != -EAGAIN)
4961                                 break;
4962                         mutex_unlock(&root->fs_info->drop_mutex);
4963
4964                         nr = trans->blocks_used;
4965                         ret = btrfs_end_transaction(trans, root);
4966                         BUG_ON(ret);
4967                         btrfs_btree_balance_dirty(root, nr);
4968                 }
4969
4970                 free_extent_buffer(reloc_root->node);
4971
4972                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
4973                                      &reloc_root->root_key);
4974                 BUG_ON(ret);
4975                 mutex_unlock(&root->fs_info->drop_mutex);
4976
4977                 nr = trans->blocks_used;
4978                 ret = btrfs_end_transaction(trans, root);
4979                 BUG_ON(ret);
4980                 btrfs_btree_balance_dirty(root, nr);
4981
4982                 kfree(prev_root);
4983                 prev_root = reloc_root;
4984         }
4985         if (prev_root) {
4986                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
4987                 kfree(prev_root);
4988         }
4989         return 0;
4990 }
4991
4992 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
4993 {
4994         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
4995         return 0;
4996 }
4997
4998 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
4999 {
5000         struct btrfs_root *reloc_root;
5001         struct btrfs_trans_handle *trans;
5002         struct btrfs_key location;
5003         int found;
5004         int ret;
5005
5006         mutex_lock(&root->fs_info->tree_reloc_mutex);
5007         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
5008         BUG_ON(ret);
5009         found = !list_empty(&root->fs_info->dead_reloc_roots);
5010         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5011
5012         if (found) {
5013                 trans = btrfs_start_transaction(root, 1);
5014                 BUG_ON(!trans);
5015                 ret = btrfs_commit_transaction(trans, root);
5016                 BUG_ON(ret);
5017         }
5018
5019         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
5020         location.offset = (u64)-1;
5021         location.type = BTRFS_ROOT_ITEM_KEY;
5022
5023         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
5024         BUG_ON(!reloc_root);
5025         btrfs_orphan_cleanup(reloc_root);
5026         return 0;
5027 }
5028
5029 static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
5030                                     struct btrfs_root *root)
5031 {
5032         struct btrfs_root *reloc_root;
5033         struct extent_buffer *eb;
5034         struct btrfs_root_item *root_item;
5035         struct btrfs_key root_key;
5036         int ret;
5037
5038         BUG_ON(!root->ref_cows);
5039         if (root->reloc_root)
5040                 return 0;
5041
5042         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
5043         BUG_ON(!root_item);
5044
5045         ret = btrfs_copy_root(trans, root, root->commit_root,
5046                               &eb, BTRFS_TREE_RELOC_OBJECTID);
5047         BUG_ON(ret);
5048
5049         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
5050         root_key.offset = root->root_key.objectid;
5051         root_key.type = BTRFS_ROOT_ITEM_KEY;
5052
5053         memcpy(root_item, &root->root_item, sizeof(root_item));
5054         btrfs_set_root_refs(root_item, 0);
5055         btrfs_set_root_bytenr(root_item, eb->start);
5056         btrfs_set_root_level(root_item, btrfs_header_level(eb));
5057         btrfs_set_root_generation(root_item, trans->transid);
5058
5059         btrfs_tree_unlock(eb);
5060         free_extent_buffer(eb);
5061
5062         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
5063                                 &root_key, root_item);
5064         BUG_ON(ret);
5065         kfree(root_item);
5066
5067         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
5068                                                  &root_key);
5069         BUG_ON(!reloc_root);
5070         reloc_root->last_trans = trans->transid;
5071         reloc_root->commit_root = NULL;
5072         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
5073
5074         root->reloc_root = reloc_root;
5075         return 0;
5076 }
5077
5078 /*
5079  * Core function of space balance.
5080  *
5081  * The idea is using reloc trees to relocate tree blocks in reference
5082  * counted roots. There is one reloc tree for each subvol, and all
5083  * reloc trees share same root key objectid. Reloc trees are snapshots
5084  * of the latest committed roots of subvols (root->commit_root).
5085  *
5086  * To relocate a tree block referenced by a subvol, there are two steps.
5087  * COW the block through subvol's reloc tree, then update block pointer
5088  * in the subvol to point to the new block. Since all reloc trees share
5089  * same root key objectid, doing special handing for tree blocks owned
5090  * by them is easy. Once a tree block has been COWed in one reloc tree,
5091  * we can use the resulting new block directly when the same block is
5092  * required to COW again through other reloc trees. By this way, relocated
5093  * tree blocks are shared between reloc trees, so they are also shared
5094  * between subvols.
5095  */
5096 static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
5097                                       struct btrfs_root *root,
5098                                       struct btrfs_path *path,
5099                                       struct btrfs_key *first_key,
5100                                       struct btrfs_ref_path *ref_path,
5101                                       struct btrfs_block_group_cache *group,
5102                                       struct inode *reloc_inode)
5103 {
5104         struct btrfs_root *reloc_root;
5105         struct extent_buffer *eb = NULL;
5106         struct btrfs_key *keys;
5107         u64 *nodes;
5108         int level;
5109         int shared_level;
5110         int lowest_level = 0;
5111         int ret;
5112
5113         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
5114                 lowest_level = ref_path->owner_objectid;
5115
5116         if (!root->ref_cows) {
5117                 path->lowest_level = lowest_level;
5118                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
5119                 BUG_ON(ret < 0);
5120                 path->lowest_level = 0;
5121                 btrfs_release_path(root, path);
5122                 return 0;
5123         }
5124
5125         mutex_lock(&root->fs_info->tree_reloc_mutex);
5126         ret = init_reloc_tree(trans, root);
5127         BUG_ON(ret);
5128         reloc_root = root->reloc_root;
5129
5130         shared_level = ref_path->shared_level;
5131         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
5132
5133         keys = ref_path->node_keys;
5134         nodes = ref_path->new_nodes;
5135         memset(&keys[shared_level + 1], 0,
5136                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
5137         memset(&nodes[shared_level + 1], 0,
5138                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
5139
5140         if (nodes[lowest_level] == 0) {
5141                 path->lowest_level = lowest_level;
5142                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5143                                         0, 1);
5144                 BUG_ON(ret);
5145                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
5146                         eb = path->nodes[level];
5147                         if (!eb || eb == reloc_root->node)
5148                                 break;
5149                         nodes[level] = eb->start;
5150                         if (level == 0)
5151                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
5152                         else
5153                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
5154                 }
5155                 if (nodes[0] &&
5156                     ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5157                         eb = path->nodes[0];
5158                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
5159                                                       group, reloc_inode);
5160                         BUG_ON(ret);
5161                 }
5162                 btrfs_release_path(reloc_root, path);
5163         } else {
5164                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
5165                                        lowest_level);
5166                 BUG_ON(ret);
5167         }
5168
5169         /*
5170          * replace tree blocks in the fs tree with tree blocks in
5171          * the reloc tree.
5172          */
5173         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
5174         BUG_ON(ret < 0);
5175
5176         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5177                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5178                                         0, 0);
5179                 BUG_ON(ret);
5180                 extent_buffer_get(path->nodes[0]);
5181                 eb = path->nodes[0];
5182                 btrfs_release_path(reloc_root, path);
5183                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
5184                 BUG_ON(ret);
5185                 free_extent_buffer(eb);
5186         }
5187
5188         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5189         path->lowest_level = 0;
5190         return 0;
5191 }
5192
5193 static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
5194                                         struct btrfs_root *root,
5195                                         struct btrfs_path *path,
5196                                         struct btrfs_key *first_key,
5197                                         struct btrfs_ref_path *ref_path)
5198 {
5199         int ret;
5200
5201         ret = relocate_one_path(trans, root, path, first_key,
5202                                 ref_path, NULL, NULL);
5203         BUG_ON(ret);
5204
5205         return 0;
5206 }
5207
5208 static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
5209                                     struct btrfs_root *extent_root,
5210                                     struct btrfs_path *path,
5211                                     struct btrfs_key *extent_key)
5212 {
5213         int ret;
5214
5215         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
5216         if (ret)
5217                 goto out;
5218         ret = btrfs_del_item(trans, extent_root, path);
5219 out:
5220         btrfs_release_path(extent_root, path);
5221         return ret;
5222 }
5223
5224 static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
5225                                                 struct btrfs_ref_path *ref_path)
5226 {
5227         struct btrfs_key root_key;
5228
5229         root_key.objectid = ref_path->root_objectid;
5230         root_key.type = BTRFS_ROOT_ITEM_KEY;
5231         if (is_cowonly_root(ref_path->root_objectid))
5232                 root_key.offset = 0;
5233         else
5234                 root_key.offset = (u64)-1;
5235
5236         return btrfs_read_fs_root_no_name(fs_info, &root_key);
5237 }
5238
5239 static noinline int relocate_one_extent(struct btrfs_root *extent_root,
5240                                         struct btrfs_path *path,
5241                                         struct btrfs_key *extent_key,
5242                                         struct btrfs_block_group_cache *group,
5243                                         struct inode *reloc_inode, int pass)
5244 {
5245         struct btrfs_trans_handle *trans;
5246         struct btrfs_root *found_root;
5247         struct btrfs_ref_path *ref_path = NULL;
5248         struct disk_extent *new_extents = NULL;
5249         int nr_extents = 0;
5250         int loops;
5251         int ret;
5252         int level;
5253         struct btrfs_key first_key;
5254         u64 prev_block = 0;
5255
5256
5257         trans = btrfs_start_transaction(extent_root, 1);
5258         BUG_ON(!trans);
5259
5260         if (extent_key->objectid == 0) {
5261                 ret = del_extent_zero(trans, extent_root, path, extent_key);
5262                 goto out;
5263         }
5264
5265         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
5266         if (!ref_path) {
5267                 ret = -ENOMEM;
5268                 goto out;
5269         }
5270
5271         for (loops = 0; ; loops++) {
5272                 if (loops == 0) {
5273                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
5274                                                    extent_key->objectid);
5275                 } else {
5276                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
5277                 }
5278                 if (ret < 0)
5279                         goto out;
5280                 if (ret > 0)
5281                         break;
5282
5283                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
5284                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
5285                         continue;
5286
5287                 found_root = read_ref_root(extent_root->fs_info, ref_path);
5288                 BUG_ON(!found_root);
5289                 /*
5290                  * for reference counted tree, only process reference paths
5291                  * rooted at the latest committed root.
5292                  */
5293                 if (found_root->ref_cows &&
5294                     ref_path->root_generation != found_root->root_key.offset)
5295                         continue;
5296
5297                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5298                         if (pass == 0) {
5299                                 /*
5300                                  * copy data extents to new locations
5301                                  */
5302                                 u64 group_start = group->key.objectid;
5303                                 ret = relocate_data_extent(reloc_inode,
5304                                                            extent_key,
5305                                                            group_start);
5306                                 if (ret < 0)
5307                                         goto out;
5308                                 break;
5309                         }
5310                         level = 0;
5311                 } else {
5312                         level = ref_path->owner_objectid;
5313                 }
5314
5315                 if (prev_block != ref_path->nodes[level]) {
5316                         struct extent_buffer *eb;
5317                         u64 block_start = ref_path->nodes[level];
5318                         u64 block_size = btrfs_level_size(found_root, level);
5319
5320                         eb = read_tree_block(found_root, block_start,
5321                                              block_size, 0);
5322                         btrfs_tree_lock(eb);
5323                         BUG_ON(level != btrfs_header_level(eb));
5324
5325                         if (level == 0)
5326                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
5327                         else
5328                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
5329
5330                         btrfs_tree_unlock(eb);
5331                         free_extent_buffer(eb);
5332                         prev_block = block_start;
5333                 }
5334
5335                 mutex_lock(&extent_root->fs_info->trans_mutex);
5336                 btrfs_record_root_in_trans(found_root);
5337                 mutex_unlock(&extent_root->fs_info->trans_mutex);
5338                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5339                         /*
5340                          * try to update data extent references while
5341                          * keeping metadata shared between snapshots.
5342                          */
5343                         if (pass == 1) {
5344                                 ret = relocate_one_path(trans, found_root,
5345                                                 path, &first_key, ref_path,
5346                                                 group, reloc_inode);
5347                                 if (ret < 0)
5348                                         goto out;
5349                                 continue;
5350                         }
5351                         /*
5352                          * use fallback method to process the remaining
5353                          * references.
5354                          */
5355                         if (!new_extents) {
5356                                 u64 group_start = group->key.objectid;
5357                                 new_extents = kmalloc(sizeof(*new_extents),
5358                                                       GFP_NOFS);
5359                                 nr_extents = 1;
5360                                 ret = get_new_locations(reloc_inode,
5361                                                         extent_key,
5362                                                         group_start, 1,
5363                                                         &new_extents,
5364                                                         &nr_extents);
5365                                 if (ret)
5366                                         goto out;
5367                         }
5368                         ret = replace_one_extent(trans, found_root,
5369                                                 path, extent_key,
5370                                                 &first_key, ref_path,
5371                                                 new_extents, nr_extents);
5372                 } else {
5373                         ret = relocate_tree_block(trans, found_root, path,
5374                                                   &first_key, ref_path);
5375                 }
5376                 if (ret < 0)
5377                         goto out;
5378         }
5379         ret = 0;
5380 out:
5381         btrfs_end_transaction(trans, extent_root);
5382         kfree(new_extents);
5383         kfree(ref_path);
5384         return ret;
5385 }
5386
5387 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
5388 {
5389         u64 num_devices;
5390         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
5391                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
5392
5393         num_devices = root->fs_info->fs_devices->rw_devices;
5394         if (num_devices == 1) {
5395                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5396                 stripped = flags & ~stripped;
5397
5398                 /* turn raid0 into single device chunks */
5399                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
5400                         return stripped;
5401
5402                 /* turn mirroring into duplication */
5403                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
5404                              BTRFS_BLOCK_GROUP_RAID10))
5405                         return stripped | BTRFS_BLOCK_GROUP_DUP;
5406                 return flags;
5407         } else {
5408                 /* they already had raid on here, just return */
5409                 if (flags & stripped)
5410                         return flags;
5411
5412                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5413                 stripped = flags & ~stripped;
5414
5415                 /* switch duplicated blocks with raid1 */
5416                 if (flags & BTRFS_BLOCK_GROUP_DUP)
5417                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
5418
5419                 /* turn single device chunks into raid0 */
5420                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
5421         }
5422         return flags;
5423 }
5424
5425 static int __alloc_chunk_for_shrink(struct btrfs_root *root,
5426                      struct btrfs_block_group_cache *shrink_block_group,
5427                      int force)
5428 {
5429         struct btrfs_trans_handle *trans;
5430         u64 new_alloc_flags;
5431         u64 calc;
5432
5433         spin_lock(&shrink_block_group->lock);
5434         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
5435                 spin_unlock(&shrink_block_group->lock);
5436
5437                 trans = btrfs_start_transaction(root, 1);
5438                 spin_lock(&shrink_block_group->lock);
5439
5440                 new_alloc_flags = update_block_group_flags(root,
5441                                                    shrink_block_group->flags);
5442                 if (new_alloc_flags != shrink_block_group->flags) {
5443                         calc =
5444                              btrfs_block_group_used(&shrink_block_group->item);
5445                 } else {
5446                         calc = shrink_block_group->key.offset;
5447                 }
5448                 spin_unlock(&shrink_block_group->lock);
5449
5450                 do_chunk_alloc(trans, root->fs_info->extent_root,
5451                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
5452
5453                 btrfs_end_transaction(trans, root);
5454         } else
5455                 spin_unlock(&shrink_block_group->lock);
5456         return 0;
5457 }
5458
5459 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
5460                                  struct btrfs_root *root,
5461                                  u64 objectid, u64 size)
5462 {
5463         struct btrfs_path *path;
5464         struct btrfs_inode_item *item;
5465         struct extent_buffer *leaf;
5466         int ret;
5467
5468         path = btrfs_alloc_path();
5469         if (!path)
5470                 return -ENOMEM;
5471
5472         path->leave_spinning = 1;
5473         ret = btrfs_insert_empty_inode(trans, root, path, objectid);
5474         if (ret)
5475                 goto out;
5476
5477         leaf = path->nodes[0];
5478         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
5479         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
5480         btrfs_set_inode_generation(leaf, item, 1);
5481         btrfs_set_inode_size(leaf, item, size);
5482         btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
5483         btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
5484         btrfs_mark_buffer_dirty(leaf);
5485         btrfs_release_path(root, path);
5486 out:
5487         btrfs_free_path(path);
5488         return ret;
5489 }
5490
5491 static noinline struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
5492                                         struct btrfs_block_group_cache *group)
5493 {
5494         struct inode *inode = NULL;
5495         struct btrfs_trans_handle *trans;
5496         struct btrfs_root *root;
5497         struct btrfs_key root_key;
5498         u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
5499         int err = 0;
5500
5501         root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
5502         root_key.type = BTRFS_ROOT_ITEM_KEY;
5503         root_key.offset = (u64)-1;
5504         root = btrfs_read_fs_root_no_name(fs_info, &root_key);
5505         if (IS_ERR(root))
5506                 return ERR_CAST(root);
5507
5508         trans = btrfs_start_transaction(root, 1);
5509         BUG_ON(!trans);
5510
5511         err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
5512         if (err)
5513                 goto out;
5514
5515         err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
5516         BUG_ON(err);
5517
5518         err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
5519                                        group->key.offset, 0, group->key.offset,
5520                                        0, 0, 0);
5521         BUG_ON(err);
5522
5523         inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
5524         if (inode->i_state & I_NEW) {
5525                 BTRFS_I(inode)->root = root;
5526                 BTRFS_I(inode)->location.objectid = objectid;
5527                 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
5528                 BTRFS_I(inode)->location.offset = 0;
5529                 btrfs_read_locked_inode(inode);
5530                 unlock_new_inode(inode);
5531                 BUG_ON(is_bad_inode(inode));
5532         } else {
5533                 BUG_ON(1);
5534         }
5535         BTRFS_I(inode)->index_cnt = group->key.objectid;
5536
5537         err = btrfs_orphan_add(trans, inode);
5538 out:
5539         btrfs_end_transaction(trans, root);
5540         if (err) {
5541                 if (inode)
5542                         iput(inode);
5543                 inode = ERR_PTR(err);
5544         }
5545         return inode;
5546 }
5547
5548 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
5549 {
5550
5551         struct btrfs_ordered_sum *sums;
5552         struct btrfs_sector_sum *sector_sum;
5553         struct btrfs_ordered_extent *ordered;
5554         struct btrfs_root *root = BTRFS_I(inode)->root;
5555         struct list_head list;
5556         size_t offset;
5557         int ret;
5558         u64 disk_bytenr;
5559
5560         INIT_LIST_HEAD(&list);
5561
5562         ordered = btrfs_lookup_ordered_extent(inode, file_pos);
5563         BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
5564
5565         disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
5566         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
5567                                        disk_bytenr + len - 1, &list);
5568
5569         while (!list_empty(&list)) {
5570                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
5571                 list_del_init(&sums->list);
5572
5573                 sector_sum = sums->sums;
5574                 sums->bytenr = ordered->start;
5575
5576                 offset = 0;
5577                 while (offset < sums->len) {
5578                         sector_sum->bytenr += ordered->start - disk_bytenr;
5579                         sector_sum++;
5580                         offset += root->sectorsize;
5581                 }
5582
5583                 btrfs_add_ordered_sum(inode, ordered, sums);
5584         }
5585         btrfs_put_ordered_extent(ordered);
5586         return 0;
5587 }
5588
5589 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
5590 {
5591         struct btrfs_trans_handle *trans;
5592         struct btrfs_path *path;
5593         struct btrfs_fs_info *info = root->fs_info;
5594         struct extent_buffer *leaf;
5595         struct inode *reloc_inode;
5596         struct btrfs_block_group_cache *block_group;
5597         struct btrfs_key key;
5598         u64 skipped;
5599         u64 cur_byte;
5600         u64 total_found;
5601         u32 nritems;
5602         int ret;
5603         int progress;
5604         int pass = 0;
5605
5606         root = root->fs_info->extent_root;
5607
5608         block_group = btrfs_lookup_block_group(info, group_start);
5609         BUG_ON(!block_group);
5610
5611         printk(KERN_INFO "btrfs relocating block group %llu flags %llu\n",
5612                (unsigned long long)block_group->key.objectid,
5613                (unsigned long long)block_group->flags);
5614
5615         path = btrfs_alloc_path();
5616         BUG_ON(!path);
5617
5618         reloc_inode = create_reloc_inode(info, block_group);
5619         BUG_ON(IS_ERR(reloc_inode));
5620
5621         __alloc_chunk_for_shrink(root, block_group, 1);
5622         set_block_group_readonly(block_group);
5623
5624         btrfs_start_delalloc_inodes(info->tree_root);
5625         btrfs_wait_ordered_extents(info->tree_root, 0);
5626 again:
5627         skipped = 0;
5628         total_found = 0;
5629         progress = 0;
5630         key.objectid = block_group->key.objectid;
5631         key.offset = 0;
5632         key.type = 0;
5633         cur_byte = key.objectid;
5634
5635         trans = btrfs_start_transaction(info->tree_root, 1);
5636         btrfs_commit_transaction(trans, info->tree_root);
5637
5638         mutex_lock(&root->fs_info->cleaner_mutex);
5639         btrfs_clean_old_snapshots(info->tree_root);
5640         btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
5641         mutex_unlock(&root->fs_info->cleaner_mutex);
5642
5643         trans = btrfs_start_transaction(info->tree_root, 1);
5644         btrfs_commit_transaction(trans, info->tree_root);
5645
5646         while (1) {
5647                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5648                 if (ret < 0)
5649                         goto out;
5650 next:
5651                 leaf = path->nodes[0];
5652                 nritems = btrfs_header_nritems(leaf);
5653                 if (path->slots[0] >= nritems) {
5654                         ret = btrfs_next_leaf(root, path);
5655                         if (ret < 0)
5656                                 goto out;
5657                         if (ret == 1) {
5658                                 ret = 0;
5659                                 break;
5660                         }
5661                         leaf = path->nodes[0];
5662                         nritems = btrfs_header_nritems(leaf);
5663                 }
5664
5665                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
5666
5667                 if (key.objectid >= block_group->key.objectid +
5668                     block_group->key.offset)
5669                         break;
5670
5671                 if (progress && need_resched()) {
5672                         btrfs_release_path(root, path);
5673                         cond_resched();
5674                         progress = 0;
5675                         continue;
5676                 }
5677                 progress = 1;
5678
5679                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
5680                     key.objectid + key.offset <= cur_byte) {
5681                         path->slots[0]++;
5682                         goto next;
5683                 }
5684
5685                 total_found++;
5686                 cur_byte = key.objectid + key.offset;
5687                 btrfs_release_path(root, path);
5688
5689                 __alloc_chunk_for_shrink(root, block_group, 0);
5690                 ret = relocate_one_extent(root, path, &key, block_group,
5691                                           reloc_inode, pass);
5692                 BUG_ON(ret < 0);
5693                 if (ret > 0)
5694                         skipped++;
5695
5696                 key.objectid = cur_byte;
5697                 key.type = 0;
5698                 key.offset = 0;
5699         }
5700
5701         btrfs_release_path(root, path);
5702
5703         if (pass == 0) {
5704                 btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
5705                 invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
5706         }
5707
5708         if (total_found > 0) {
5709                 printk(KERN_INFO "btrfs found %llu extents in pass %d\n",
5710                        (unsigned long long)total_found, pass);
5711                 pass++;
5712                 if (total_found == skipped && pass > 2) {
5713                         iput(reloc_inode);
5714                         reloc_inode = create_reloc_inode(info, block_group);
5715                         pass = 0;
5716                 }
5717                 goto again;
5718         }
5719
5720         /* delete reloc_inode */
5721         iput(reloc_inode);
5722
5723         /* unpin extents in this range */
5724         trans = btrfs_start_transaction(info->tree_root, 1);
5725         btrfs_commit_transaction(trans, info->tree_root);
5726
5727         spin_lock(&block_group->lock);
5728         WARN_ON(block_group->pinned > 0);
5729         WARN_ON(block_group->reserved > 0);
5730         WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
5731         spin_unlock(&block_group->lock);
5732         put_block_group(block_group);
5733         ret = 0;
5734 out:
5735         btrfs_free_path(path);
5736         return ret;
5737 }
5738
5739 static int find_first_block_group(struct btrfs_root *root,
5740                 struct btrfs_path *path, struct btrfs_key *key)
5741 {
5742         int ret = 0;
5743         struct btrfs_key found_key;
5744         struct extent_buffer *leaf;
5745         int slot;
5746
5747         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
5748         if (ret < 0)
5749                 goto out;
5750
5751         while (1) {
5752                 slot = path->slots[0];
5753                 leaf = path->nodes[0];
5754                 if (slot >= btrfs_header_nritems(leaf)) {
5755                         ret = btrfs_next_leaf(root, path);
5756                         if (ret == 0)
5757                                 continue;
5758                         if (ret < 0)
5759                                 goto out;
5760                         break;
5761                 }
5762                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5763
5764                 if (found_key.objectid >= key->objectid &&
5765                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
5766                         ret = 0;
5767                         goto out;
5768                 }
5769                 path->slots[0]++;
5770         }
5771         ret = -ENOENT;
5772 out:
5773         return ret;
5774 }
5775
5776 int btrfs_free_block_groups(struct btrfs_fs_info *info)
5777 {
5778         struct btrfs_block_group_cache *block_group;
5779         struct btrfs_space_info *space_info;
5780         struct rb_node *n;
5781
5782         spin_lock(&info->block_group_cache_lock);
5783         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
5784                 block_group = rb_entry(n, struct btrfs_block_group_cache,
5785                                        cache_node);
5786                 rb_erase(&block_group->cache_node,
5787                          &info->block_group_cache_tree);
5788                 spin_unlock(&info->block_group_cache_lock);
5789
5790                 btrfs_remove_free_space_cache(block_group);
5791                 down_write(&block_group->space_info->groups_sem);
5792                 list_del(&block_group->list);
5793                 up_write(&block_group->space_info->groups_sem);
5794
5795                 WARN_ON(atomic_read(&block_group->count) != 1);
5796                 kfree(block_group);
5797
5798                 spin_lock(&info->block_group_cache_lock);
5799         }
5800         spin_unlock(&info->block_group_cache_lock);
5801
5802         /* now that all the block groups are freed, go through and
5803          * free all the space_info structs.  This is only called during
5804          * the final stages of unmount, and so we know nobody is
5805          * using them.  We call synchronize_rcu() once before we start,
5806          * just to be on the safe side.
5807          */
5808         synchronize_rcu();
5809
5810         while(!list_empty(&info->space_info)) {
5811                 space_info = list_entry(info->space_info.next,
5812                                         struct btrfs_space_info,
5813                                         list);
5814
5815                 list_del(&space_info->list);
5816                 kfree(space_info);
5817         }
5818         return 0;
5819 }
5820
5821 int btrfs_read_block_groups(struct btrfs_root *root)
5822 {
5823         struct btrfs_path *path;
5824         int ret;
5825         struct btrfs_block_group_cache *cache;
5826         struct btrfs_fs_info *info = root->fs_info;
5827         struct btrfs_space_info *space_info;
5828         struct btrfs_key key;
5829         struct btrfs_key found_key;
5830         struct extent_buffer *leaf;
5831
5832         root = info->extent_root;
5833         key.objectid = 0;
5834         key.offset = 0;
5835         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
5836         path = btrfs_alloc_path();
5837         if (!path)
5838                 return -ENOMEM;
5839
5840         while (1) {
5841                 ret = find_first_block_group(root, path, &key);
5842                 if (ret > 0) {
5843                         ret = 0;
5844                         goto error;
5845                 }
5846                 if (ret != 0)
5847                         goto error;
5848
5849                 leaf = path->nodes[0];
5850                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5851                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
5852                 if (!cache) {
5853                         ret = -ENOMEM;
5854                         break;
5855                 }
5856
5857                 atomic_set(&cache->count, 1);
5858                 spin_lock_init(&cache->lock);
5859                 mutex_init(&cache->alloc_mutex);
5860                 mutex_init(&cache->cache_mutex);
5861                 INIT_LIST_HEAD(&cache->list);
5862                 read_extent_buffer(leaf, &cache->item,
5863                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
5864                                    sizeof(cache->item));
5865                 memcpy(&cache->key, &found_key, sizeof(found_key));
5866
5867                 key.objectid = found_key.objectid + found_key.offset;
5868                 btrfs_release_path(root, path);
5869                 cache->flags = btrfs_block_group_flags(&cache->item);
5870
5871                 ret = update_space_info(info, cache->flags, found_key.offset,
5872                                         btrfs_block_group_used(&cache->item),
5873                                         &space_info);
5874                 BUG_ON(ret);
5875                 cache->space_info = space_info;
5876                 down_write(&space_info->groups_sem);
5877                 list_add_tail(&cache->list, &space_info->block_groups);
5878                 up_write(&space_info->groups_sem);
5879
5880                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
5881                 BUG_ON(ret);
5882
5883                 set_avail_alloc_bits(root->fs_info, cache->flags);
5884                 if (btrfs_chunk_readonly(root, cache->key.objectid))
5885                         set_block_group_readonly(cache);
5886         }
5887         ret = 0;
5888 error:
5889         btrfs_free_path(path);
5890         return ret;
5891 }
5892
5893 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
5894                            struct btrfs_root *root, u64 bytes_used,
5895                            u64 type, u64 chunk_objectid, u64 chunk_offset,
5896                            u64 size)
5897 {
5898         int ret;
5899         struct btrfs_root *extent_root;
5900         struct btrfs_block_group_cache *cache;
5901
5902         extent_root = root->fs_info->extent_root;
5903
5904         root->fs_info->last_trans_log_full_commit = trans->transid;
5905
5906         cache = kzalloc(sizeof(*cache), GFP_NOFS);
5907         if (!cache)
5908                 return -ENOMEM;
5909
5910         cache->key.objectid = chunk_offset;
5911         cache->key.offset = size;
5912         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
5913         atomic_set(&cache->count, 1);
5914         spin_lock_init(&cache->lock);
5915         mutex_init(&cache->alloc_mutex);
5916         mutex_init(&cache->cache_mutex);
5917         INIT_LIST_HEAD(&cache->list);
5918
5919         btrfs_set_block_group_used(&cache->item, bytes_used);
5920         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
5921         cache->flags = type;
5922         btrfs_set_block_group_flags(&cache->item, type);
5923
5924         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
5925                                 &cache->space_info);
5926         BUG_ON(ret);
5927         down_write(&cache->space_info->groups_sem);
5928         list_add_tail(&cache->list, &cache->space_info->block_groups);
5929         up_write(&cache->space_info->groups_sem);
5930
5931         ret = btrfs_add_block_group_cache(root->fs_info, cache);
5932         BUG_ON(ret);
5933
5934         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
5935                                 sizeof(cache->item));
5936         BUG_ON(ret);
5937
5938         set_avail_alloc_bits(extent_root->fs_info, type);
5939
5940         return 0;
5941 }
5942
5943 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
5944                              struct btrfs_root *root, u64 group_start)
5945 {
5946         struct btrfs_path *path;
5947         struct btrfs_block_group_cache *block_group;
5948         struct btrfs_key key;
5949         int ret;
5950
5951         root = root->fs_info->extent_root;
5952
5953         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
5954         BUG_ON(!block_group);
5955         BUG_ON(!block_group->ro);
5956
5957         memcpy(&key, &block_group->key, sizeof(key));
5958
5959         path = btrfs_alloc_path();
5960         BUG_ON(!path);
5961
5962         spin_lock(&root->fs_info->block_group_cache_lock);
5963         rb_erase(&block_group->cache_node,
5964                  &root->fs_info->block_group_cache_tree);
5965         spin_unlock(&root->fs_info->block_group_cache_lock);
5966         btrfs_remove_free_space_cache(block_group);
5967         down_write(&block_group->space_info->groups_sem);
5968         list_del(&block_group->list);
5969         up_write(&block_group->space_info->groups_sem);
5970
5971         spin_lock(&block_group->space_info->lock);
5972         block_group->space_info->total_bytes -= block_group->key.offset;
5973         block_group->space_info->bytes_readonly -= block_group->key.offset;
5974         spin_unlock(&block_group->space_info->lock);
5975         block_group->space_info->full = 0;
5976
5977         put_block_group(block_group);
5978         put_block_group(block_group);
5979
5980         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
5981         if (ret > 0)
5982                 ret = -EIO;
5983         if (ret < 0)
5984                 goto out;
5985
5986         ret = btrfs_del_item(trans, root, path);
5987 out:
5988         btrfs_free_path(path);
5989         return ret;
5990 }