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