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 "hash.h"
  22 #include "crc32c.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "print-tree.h"
  26 #include "transaction.h"
  27 #include "volumes.h"
  28 #include "locking.h"
  29
  30 #define BLOCK_GROUP_DATA     EXTENT_WRITEBACK
  31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
  32 #define BLOCK_GROUP_SYSTEM   EXTENT_NEW
  33
  34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
  35
  36 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  37                                  btrfs_root *extent_root);
  38 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  39                                btrfs_root *extent_root);
  40 static struct btrfs_block_group_cache *
  41 __btrfs_find_block_group(struct btrfs_root *root,
  42                          struct btrfs_block_group_cache *hint,
  43                          u64 search_start, int data, int owner);
  44
  45 void maybe_lock_mutex(struct btrfs_root *root)
  46 {
  47         if (root != root->fs_info->extent_root &&
  48             root != root->fs_info->chunk_root &&
  49             root != root->fs_info->dev_root) {
  50                 mutex_lock(&root->fs_info->alloc_mutex);
  51         }
  52 }
  53
  54 void maybe_unlock_mutex(struct btrfs_root *root)
  55 {
  56         if (root != root->fs_info->extent_root &&
  57             root != root->fs_info->chunk_root &&
  58             root != root->fs_info->dev_root) {
  59                 mutex_unlock(&root->fs_info->alloc_mutex);
  60         }
  61 }
  62
  63 static int cache_block_group(struct btrfs_root *root,
  64                              struct btrfs_block_group_cache *block_group)
  65 {
  66         struct btrfs_path *path;
  67         int ret;
  68         struct btrfs_key key;
  69         struct extent_buffer *leaf;
  70         struct extent_io_tree *free_space_cache;
  71         int slot;
  72         u64 last = 0;
  73         u64 hole_size;
  74         u64 first_free;
  75         int found = 0;
  76
  77         if (!block_group)
  78                 return 0;
  79
  80         root = root->fs_info->extent_root;
  81         free_space_cache = &root->fs_info->free_space_cache;
  82
  83         if (block_group->cached)
  84                 return 0;
  85
  86         path = btrfs_alloc_path();
  87         if (!path)
  88                 return -ENOMEM;
  89
  90         path->reada = 2;
  91         /*
  92          * we get into deadlocks with paths held by callers of this function.
  93          * since the alloc_mutex is protecting things right now, just
  94          * skip the locking here
  95          */
  96         path->skip_locking = 1;
  97         first_free = block_group->key.objectid;
  98         key.objectid = block_group->key.objectid;
  99         key.offset = 0;
 100         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 101         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 102         if (ret < 0)
 103                 return ret;
 104         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
 105         if (ret < 0)
 106                 return ret;
 107         if (ret == 0) {
 108                 leaf = path->nodes[0];
 109                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 110                 if (key.objectid + key.offset > first_free)
 111                         first_free = key.objectid + key.offset;
 112         }
 113         while(1) {
 114                 leaf = path->nodes[0];
 115                 slot = path->slots[0];
 116                 if (slot >= btrfs_header_nritems(leaf)) {
 117                         ret = btrfs_next_leaf(root, path);
 118                         if (ret < 0)
 119                                 goto err;
 120                         if (ret == 0) {
 121                                 continue;
 122                         } else {
 123                                 break;
 124                         }
 125                 }
 126                 btrfs_item_key_to_cpu(leaf, &key, slot);
 127                 if (key.objectid < block_group->key.objectid) {
 128                         goto next;
 129                 }
 130                 if (key.objectid >= block_group->key.objectid +
 131                     block_group->key.offset) {
 132                         break;
 133                 }
 134
 135                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 136                         if (!found) {
 137                                 last = first_free;
 138                                 found = 1;
 139                         }
 140                         if (key.objectid > last) {
 141                                 hole_size = key.objectid - last;
 142                                 set_extent_dirty(free_space_cache, last,
 143                                                  last + hole_size - 1,
 144                                                  GFP_NOFS);
 145                         }
 146                         last = key.objectid + key.offset;
 147                 }
 148 next:
 149                 path->slots[0]++;
 150         }
 151
 152         if (!found)
 153                 last = first_free;
 154         if (block_group->key.objectid +
 155             block_group->key.offset > last) {
 156                 hole_size = block_group->key.objectid +
 157                         block_group->key.offset - last;
 158                 set_extent_dirty(free_space_cache, last,
 159                                  last + hole_size - 1, GFP_NOFS);
 160         }
 161         block_group->cached = 1;
 162 err:
 163         btrfs_free_path(path);
 164         return 0;
 165 }
 166
 167 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
 168                                                        btrfs_fs_info *info,
 169                                                          u64 bytenr)
 170 {
 171         struct extent_io_tree *block_group_cache;
 172         struct btrfs_block_group_cache *block_group = NULL;
 173         u64 ptr;
 174         u64 start;
 175         u64 end;
 176         int ret;
 177
 178         bytenr = max_t(u64, bytenr,
 179                        BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 180         block_group_cache = &info->block_group_cache;
 181         ret = find_first_extent_bit(block_group_cache,
 182                                     bytenr, &start, &end,
 183                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 184                                     BLOCK_GROUP_SYSTEM);
 185         if (ret) {
 186                 return NULL;
 187         }
 188         ret = get_state_private(block_group_cache, start, &ptr);
 189         if (ret)
 190                 return NULL;
 191
 192         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 193         return block_group;
 194 }
 195
 196 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 197                                                          btrfs_fs_info *info,
 198                                                          u64 bytenr)
 199 {
 200         struct extent_io_tree *block_group_cache;
 201         struct btrfs_block_group_cache *block_group = NULL;
 202         u64 ptr;
 203         u64 start;
 204         u64 end;
 205         int ret;
 206
 207         bytenr = max_t(u64, bytenr,
 208                        BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 209         block_group_cache = &info->block_group_cache;
 210         ret = find_first_extent_bit(block_group_cache,
 211                                     bytenr, &start, &end,
 212                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 213                                     BLOCK_GROUP_SYSTEM);
 214         if (ret) {
 215                 return NULL;
 216         }
 217         ret = get_state_private(block_group_cache, start, &ptr);
 218         if (ret)
 219                 return NULL;
 220
 221         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 222         if (block_group->key.objectid <= bytenr && bytenr <
 223             block_group->key.objectid + block_group->key.offset)
 224                 return block_group;
 225         return NULL;
 226 }
 227
 228 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 229 {
 230         return (cache->flags & bits) == bits;
 231 }
 232
 233 static int noinline find_search_start(struct btrfs_root *root,
 234                               struct btrfs_block_group_cache **cache_ret,
 235                               u64 *start_ret, u64 num, int data)
 236 {
 237         int ret;
 238         struct btrfs_block_group_cache *cache = *cache_ret;
 239         struct extent_io_tree *free_space_cache;
 240         struct extent_state *state;
 241         u64 last;
 242         u64 start = 0;
 243         u64 cache_miss = 0;
 244         u64 total_fs_bytes;
 245         u64 search_start = *start_ret;
 246         int wrapped = 0;
 247
 248         total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 249         free_space_cache = &root->fs_info->free_space_cache;
 250
 251         if (!cache)
 252                 goto out;
 253
 254 again:
 255         ret = cache_block_group(root, cache);
 256         if (ret) {
 257                 goto out;
 258         }
 259
 260         last = max(search_start, cache->key.objectid);
 261         if (!block_group_bits(cache, data) || cache->ro)
 262                 goto new_group;
 263
 264         spin_lock_irq(&free_space_cache->lock);
 265         state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);
 266         while(1) {
 267                 if (!state) {
 268                         if (!cache_miss)
 269                                 cache_miss = last;
 270                         spin_unlock_irq(&free_space_cache->lock);
 271                         goto new_group;
 272                 }
 273
 274                 start = max(last, state->start);
 275                 last = state->end + 1;
 276                 if (last - start < num) {
 277                         do {
 278                                 state = extent_state_next(state);
 279                         } while(state && !(state->state & EXTENT_DIRTY));
 280                         continue;
 281                 }
 282                 spin_unlock_irq(&free_space_cache->lock);
 283                 if (cache->ro) {
 284                         goto new_group;
 285                 }
 286                 if (start + num > cache->key.objectid + cache->key.offset)
 287                         goto new_group;
 288                 if (!block_group_bits(cache, data)) {
 289                         printk("block group bits don't match %Lu %d\n", cache->flags, data);
 290                 }
 291                 *start_ret = start;
 292                 return 0;
 293         }
 294 out:
 295         cache = btrfs_lookup_block_group(root->fs_info, search_start);
 296         if (!cache) {
 297                 printk("Unable to find block group for %Lu\n", search_start);
 298                 WARN_ON(1);
 299         }
 300         return -ENOSPC;
 301
 302 new_group:
 303         last = cache->key.objectid + cache->key.offset;
 304 wrapped:
 305         cache = btrfs_lookup_first_block_group(root->fs_info, last);
 306         if (!cache || cache->key.objectid >= total_fs_bytes) {
 307 no_cache:
 308                 if (!wrapped) {
 309                         wrapped = 1;
 310                         last = search_start;
 311                         goto wrapped;
 312                 }
 313                 goto out;
 314         }
 315         if (cache_miss && !cache->cached) {
 316                 cache_block_group(root, cache);
 317                 last = cache_miss;
 318                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 319         }
 320         cache_miss = 0;
 321         cache = __btrfs_find_block_group(root, cache, last, data, 0);
 322         if (!cache)
 323                 goto no_cache;
 324         *cache_ret = cache;
 325         goto again;
 326 }
 327
 328 static u64 div_factor(u64 num, int factor)
 329 {
 330         if (factor == 10)
 331                 return num;
 332         num *= factor;
 333         do_div(num, 10);
 334         return num;
 335 }
 336
 337 static int block_group_state_bits(u64 flags)
 338 {
 339         int bits = 0;
 340         if (flags & BTRFS_BLOCK_GROUP_DATA)
 341                 bits |= BLOCK_GROUP_DATA;
 342         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 343                 bits |= BLOCK_GROUP_METADATA;
 344         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 345                 bits |= BLOCK_GROUP_SYSTEM;
 346         return bits;
 347 }
 348
 349 static struct btrfs_block_group_cache *
 350 __btrfs_find_block_group(struct btrfs_root *root,
 351                          struct btrfs_block_group_cache *hint,
 352                          u64 search_start, int data, int owner)
 353 {
 354         struct btrfs_block_group_cache *cache;
 355         struct extent_io_tree *block_group_cache;
 356         struct btrfs_block_group_cache *found_group = NULL;
 357         struct btrfs_fs_info *info = root->fs_info;
 358         u64 used;
 359         u64 last = 0;
 360         u64 start;
 361         u64 end;
 362         u64 free_check;
 363         u64 ptr;
 364         int bit;
 365         int ret;
 366         int full_search = 0;
 367         int factor = 10;
 368         int wrapped = 0;
 369
 370         block_group_cache = &info->block_group_cache;
 371
 372         if (data & BTRFS_BLOCK_GROUP_METADATA)
 373                 factor = 9;
 374
 375         bit = block_group_state_bits(data);
 376
 377         if (search_start) {
 378                 struct btrfs_block_group_cache *shint;
 379                 shint = btrfs_lookup_first_block_group(info, search_start);
 380                 if (shint && block_group_bits(shint, data) && !shint->ro) {
 381                         used = btrfs_block_group_used(&shint->item);
 382                         if (used + shint->pinned <
 383                             div_factor(shint->key.offset, factor)) {
 384                                 return shint;
 385                         }
 386                 }
 387         }
 388         if (hint && !hint->ro && block_group_bits(hint, data)) {
 389                 used = btrfs_block_group_used(&hint->item);
 390                 if (used + hint->pinned <
 391                     div_factor(hint->key.offset, factor)) {
 392                         return hint;
 393                 }
 394                 last = hint->key.objectid + hint->key.offset;
 395         } else {
 396                 if (hint)
 397                         last = max(hint->key.objectid, search_start);
 398                 else
 399                         last = search_start;
 400         }
 401 again:
 402         while(1) {
 403                 ret = find_first_extent_bit(block_group_cache, last,
 404                                             &start, &end, bit);
 405                 if (ret)
 406                         break;
 407
 408                 ret = get_state_private(block_group_cache, start, &ptr);
 409                 if (ret) {
 410                         last = end + 1;
 411                         continue;
 412                 }
 413
 414                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 415                 last = cache->key.objectid + cache->key.offset;
 416                 used = btrfs_block_group_used(&cache->item);
 417
 418                 if (!cache->ro && block_group_bits(cache, data)) {
 419                         free_check = div_factor(cache->key.offset, factor);
 420                         if (used + cache->pinned < free_check) {
 421                                 found_group = cache;
 422                                 goto found;
 423                         }
 424                 }
 425                 cond_resched();
 426         }
 427         if (!wrapped) {
 428                 last = search_start;
 429                 wrapped = 1;
 430                 goto again;
 431         }
 432         if (!full_search && factor < 10) {
 433                 last = search_start;
 434                 full_search = 1;
 435                 factor = 10;
 436                 goto again;
 437         }
 438 found:
 439         return found_group;
 440 }
 441
 442 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 443                                                  struct btrfs_block_group_cache
 444                                                  *hint, u64 search_start,
 445                                                  int data, int owner)
 446 {
 447
 448         struct btrfs_block_group_cache *ret;
 449         mutex_lock(&root->fs_info->alloc_mutex);
 450         ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
 451         mutex_unlock(&root->fs_info->alloc_mutex);
 452         return ret;
 453 }
 454 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
 455                            u64 owner, u64 owner_offset)
 456 {
 457         u32 high_crc = ~(u32)0;
 458         u32 low_crc = ~(u32)0;
 459         __le64 lenum;
 460         lenum = cpu_to_le64(root_objectid);
 461         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 462         lenum = cpu_to_le64(ref_generation);
 463         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 464         if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
 465                 lenum = cpu_to_le64(owner);
 466                 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 467                 lenum = cpu_to_le64(owner_offset);
 468                 low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 469         }
 470         return ((u64)high_crc << 32) | (u64)low_crc;
 471 }
 472
 473 static int match_extent_ref(struct extent_buffer *leaf,
 474                             struct btrfs_extent_ref *disk_ref,
 475                             struct btrfs_extent_ref *cpu_ref)
 476 {
 477         int ret;
 478         int len;
 479
 480         if (cpu_ref->objectid)
 481                 len = sizeof(*cpu_ref);
 482         else
 483                 len = 2 * sizeof(u64);
 484         ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
 485                                    len);
 486         return ret == 0;
 487 }
 488
 489 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
 490                                           struct btrfs_root *root,
 491                                           struct btrfs_path *path, u64 bytenr,
 492                                           u64 root_objectid,
 493                                           u64 ref_generation, u64 owner,
 494                                           u64 owner_offset, int del)
 495 {
 496         u64 hash;
 497         struct btrfs_key key;
 498         struct btrfs_key found_key;
 499         struct btrfs_extent_ref ref;
 500         struct extent_buffer *leaf;
 501         struct btrfs_extent_ref *disk_ref;
 502         int ret;
 503         int ret2;
 504
 505         btrfs_set_stack_ref_root(&ref, root_objectid);
 506         btrfs_set_stack_ref_generation(&ref, ref_generation);
 507         btrfs_set_stack_ref_objectid(&ref, owner);
 508         btrfs_set_stack_ref_offset(&ref, owner_offset);
 509
 510         hash = hash_extent_ref(root_objectid, ref_generation, owner,
 511                                owner_offset);
 512         key.offset = hash;
 513         key.objectid = bytenr;
 514         key.type = BTRFS_EXTENT_REF_KEY;
 515
 516         while (1) {
 517                 ret = btrfs_search_slot(trans, root, &key, path,
 518                                         del ? -1 : 0, del);
 519                 if (ret < 0)
 520                         goto out;
 521                 leaf = path->nodes[0];
 522                 if (ret != 0) {
 523                         u32 nritems = btrfs_header_nritems(leaf);
 524                         if (path->slots[0] >= nritems) {
 525                                 ret2 = btrfs_next_leaf(root, path);
 526                                 if (ret2)
 527                                         goto out;
 528                                 leaf = path->nodes[0];
 529                         }
 530                         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 531                         if (found_key.objectid != bytenr ||
 532                             found_key.type != BTRFS_EXTENT_REF_KEY)
 533                                 goto out;
 534                         key.offset = found_key.offset;
 535                         if (del) {
 536                                 btrfs_release_path(root, path);
 537                                 continue;
 538                         }
 539                 }
 540                 disk_ref = btrfs_item_ptr(path->nodes[0],
 541                                           path->slots[0],
 542                                           struct btrfs_extent_ref);
 543                 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
 544                         ret = 0;
 545                         goto out;
 546                 }
 547                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 548                 key.offset = found_key.offset + 1;
 549                 btrfs_release_path(root, path);
 550         }
 551 out:
 552         return ret;
 553 }
 554
 555 /*
 556  * Back reference rules.  Back refs have three main goals:
 557  *
 558  * 1) differentiate between all holders of references to an extent so that
 559  *    when a reference is dropped we can make sure it was a valid reference
 560  *    before freeing the extent.
 561  *
 562  * 2) Provide enough information to quickly find the holders of an extent
 563  *    if we notice a given block is corrupted or bad.
 564  *
 565  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 566  *    maintenance.  This is actually the same as #2, but with a slightly
 567  *    different use case.
 568  *
 569  * File extents can be referenced by:
 570  *
 571  * - multiple snapshots, subvolumes, or different generations in one subvol
 572  * - different files inside a single subvolume (in theory, not implemented yet)
 573  * - different offsets inside a file (bookend extents in file.c)
 574  *
 575  * The extent ref structure has fields for:
 576  *
 577  * - Objectid of the subvolume root
 578  * - Generation number of the tree holding the reference
 579  * - objectid of the file holding the reference
 580  * - offset in the file corresponding to the key holding the reference
 581  *
 582  * When a file extent is allocated the fields are filled in:
 583  *     (root_key.objectid, trans->transid, inode objectid, offset in file)
 584  *
 585  * When a leaf is cow'd new references are added for every file extent found
 586  * in the leaf.  It looks the same as the create case, but trans->transid
 587  * will be different when the block is cow'd.
 588  *
 589  *     (root_key.objectid, trans->transid, inode objectid, offset in file)
 590  *
 591  * When a file extent is removed either during snapshot deletion or file
 592  * truncation, the corresponding back reference is found
 593  * by searching for:
 594  *
 595  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 596  *      inode objectid, offset in file)
 597  *
 598  * Btree extents can be referenced by:
 599  *
 600  * - Different subvolumes
 601  * - Different generations of the same subvolume
 602  *
 603  * Storing sufficient information for a full reverse mapping of a btree
 604  * block would require storing the lowest key of the block in the backref,
 605  * and it would require updating that lowest key either before write out or
 606  * every time it changed.  Instead, the objectid of the lowest key is stored
 607  * along with the level of the tree block.  This provides a hint
 608  * about where in the btree the block can be found.  Searches through the
 609  * btree only need to look for a pointer to that block, so they stop one
 610  * level higher than the level recorded in the backref.
 611  *
 612  * Some btrees do not do reference counting on their extents.  These
 613  * include the extent tree and the tree of tree roots.  Backrefs for these
 614  * trees always have a generation of zero.
 615  *
 616  * When a tree block is created, back references are inserted:
 617  *
 618  * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
 619  *
 620  * When a tree block is cow'd in a reference counted root,
 621  * new back references are added for all the blocks it points to.
 622  * These are of the form (trans->transid will have increased since creation):
 623  *
 624  * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
 625  *
 626  * Because the lowest_key_objectid and the level are just hints
 627  * they are not used when backrefs are deleted.  When a backref is deleted:
 628  *
 629  * if backref was for a tree root:
 630  *     root_objectid = root->root_key.objectid
 631  * else
 632  *     root_objectid = btrfs_header_owner(parent)
 633  *
 634  * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
 635  *
 636  * Back Reference Key hashing:
 637  *
 638  * Back references have four fields, each 64 bits long.  Unfortunately,
 639  * This is hashed into a single 64 bit number and placed into the key offset.
 640  * The key objectid corresponds to the first byte in the extent, and the
 641  * key type is set to BTRFS_EXTENT_REF_KEY
 642  */
 643 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
 644                                  struct btrfs_root *root,
 645                                  struct btrfs_path *path, u64 bytenr,
 646                                  u64 root_objectid, u64 ref_generation,
 647                                  u64 owner, u64 owner_offset)
 648 {
 649         u64 hash;
 650         struct btrfs_key key;
 651         struct btrfs_extent_ref ref;
 652         struct btrfs_extent_ref *disk_ref;
 653         int ret;
 654
 655         btrfs_set_stack_ref_root(&ref, root_objectid);
 656         btrfs_set_stack_ref_generation(&ref, ref_generation);
 657         btrfs_set_stack_ref_objectid(&ref, owner);
 658         btrfs_set_stack_ref_offset(&ref, owner_offset);
 659
 660         hash = hash_extent_ref(root_objectid, ref_generation, owner,
 661                                owner_offset);
 662         key.offset = hash;
 663         key.objectid = bytenr;
 664         key.type = BTRFS_EXTENT_REF_KEY;
 665
 666         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
 667         while (ret == -EEXIST) {
 668                 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 669                                           struct btrfs_extent_ref);
 670                 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
 671                         goto out;
 672                 key.offset++;
 673                 btrfs_release_path(root, path);
 674                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 675                                               sizeof(ref));
 676         }
 677         if (ret)
 678                 goto out;
 679         disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 680                                   struct btrfs_extent_ref);
 681         write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
 682                             sizeof(ref));
 683         btrfs_mark_buffer_dirty(path->nodes[0]);
 684 out:
 685         btrfs_release_path(root, path);
 686         return ret;
 687 }
 688
 689 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 690                                 struct btrfs_root *root,
 691                                 u64 bytenr, u64 num_bytes,
 692                                 u64 root_objectid, u64 ref_generation,
 693                                 u64 owner, u64 owner_offset)
 694 {
 695         struct btrfs_path *path;
 696         int ret;
 697         struct btrfs_key key;
 698         struct extent_buffer *l;
 699         struct btrfs_extent_item *item;
 700         u32 refs;
 701
 702         WARN_ON(num_bytes < root->sectorsize);
 703         path = btrfs_alloc_path();
 704         if (!path)
 705                 return -ENOMEM;
 706
 707         path->reada = 1;
 708         key.objectid = bytenr;
 709         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 710         key.offset = num_bytes;
 711         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 712                                 0, 1);
 713         if (ret < 0)
 714                 return ret;
 715         if (ret != 0) {
 716                 BUG();
 717         }
 718         BUG_ON(ret != 0);
 719         l = path->nodes[0];
 720         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 721         refs = btrfs_extent_refs(l, item);
 722         btrfs_set_extent_refs(l, item, refs + 1);
 723         btrfs_mark_buffer_dirty(path->nodes[0]);
 724
 725         btrfs_release_path(root->fs_info->extent_root, path);
 726
 727         path->reada = 1;
 728         ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
 729                                           path, bytenr, root_objectid,
 730                                           ref_generation, owner, owner_offset);
 731         BUG_ON(ret);
 732         finish_current_insert(trans, root->fs_info->extent_root);
 733         del_pending_extents(trans, root->fs_info->extent_root);
 734
 735         btrfs_free_path(path);
 736         return 0;
 737 }
 738
 739 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 740                                 struct btrfs_root *root,
 741                                 u64 bytenr, u64 num_bytes,
 742                                 u64 root_objectid, u64 ref_generation,
 743                                 u64 owner, u64 owner_offset)
 744 {
 745         int ret;
 746
 747         mutex_lock(&root->fs_info->alloc_mutex);
 748         ret = __btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
 749                                      root_objectid, ref_generation,
 750                                      owner, owner_offset);
 751         mutex_unlock(&root->fs_info->alloc_mutex);
 752         return ret;
 753 }
 754
 755 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
 756                          struct btrfs_root *root)
 757 {
 758         finish_current_insert(trans, root->fs_info->extent_root);
 759         del_pending_extents(trans, root->fs_info->extent_root);
 760         return 0;
 761 }
 762
 763 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
 764                              struct btrfs_root *root, u64 bytenr,
 765                              u64 num_bytes, u32 *refs)
 766 {
 767         struct btrfs_path *path;
 768         int ret;
 769         struct btrfs_key key;
 770         struct extent_buffer *l;
 771         struct btrfs_extent_item *item;
 772
 773         WARN_ON(num_bytes < root->sectorsize);
 774         path = btrfs_alloc_path();
 775         path->reada = 1;
 776         key.objectid = bytenr;
 777         key.offset = num_bytes;
 778         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 779         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 780                                 0, 0);
 781         if (ret < 0)
 782                 goto out;
 783         if (ret != 0) {
 784                 btrfs_print_leaf(root, path->nodes[0]);
 785                 printk("failed to find block number %Lu\n", bytenr);
 786                 BUG();
 787         }
 788         l = path->nodes[0];
 789         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 790         *refs = btrfs_extent_refs(l, item);
 791 out:
 792         btrfs_free_path(path);
 793         return 0;
 794 }
 795
 796 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
 797                                   struct btrfs_path *count_path,
 798                                   u64 expected_owner,
 799                                   u64 first_extent)
 800 {
 801         struct btrfs_root *extent_root = root->fs_info->extent_root;
 802         struct btrfs_path *path;
 803         u64 bytenr;
 804         u64 found_objectid;
 805         u64 found_owner;
 806         u64 root_objectid = root->root_key.objectid;
 807         u32 total_count = 0;
 808         u32 extent_refs;
 809         u32 cur_count;
 810         u32 nritems;
 811         int ret;
 812         struct btrfs_key key;
 813         struct btrfs_key found_key;
 814         struct extent_buffer *l;
 815         struct btrfs_extent_item *item;
 816         struct btrfs_extent_ref *ref_item;
 817         int level = -1;
 818
 819         /* FIXME, needs locking */
 820         BUG();
 821
 822         mutex_lock(&root->fs_info->alloc_mutex);
 823         path = btrfs_alloc_path();
 824 again:
 825         if (level == -1)
 826                 bytenr = first_extent;
 827         else
 828                 bytenr = count_path->nodes[level]->start;
 829
 830         cur_count = 0;
 831         key.objectid = bytenr;
 832         key.offset = 0;
 833
 834         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 835         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 836         if (ret < 0)
 837                 goto out;
 838         BUG_ON(ret == 0);
 839
 840         l = path->nodes[0];
 841         btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
 842
 843         if (found_key.objectid != bytenr ||
 844             found_key.type != BTRFS_EXTENT_ITEM_KEY) {
 845                 goto out;
 846         }
 847
 848         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 849         extent_refs = btrfs_extent_refs(l, item);
 850         while (1) {
 851                 l = path->nodes[0];
 852                 nritems = btrfs_header_nritems(l);
 853                 if (path->slots[0] >= nritems) {
 854                         ret = btrfs_next_leaf(extent_root, path);
 855                         if (ret == 0)
 856                                 continue;
 857                         break;
 858                 }
 859                 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
 860                 if (found_key.objectid != bytenr)
 861                         break;
 862
 863                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
 864                         path->slots[0]++;
 865                         continue;
 866                 }
 867
 868                 cur_count++;
 869                 ref_item = btrfs_item_ptr(l, path->slots[0],
 870                                           struct btrfs_extent_ref);
 871                 found_objectid = btrfs_ref_root(l, ref_item);
 872
 873                 if (found_objectid != root_objectid) {
 874                         total_count = 2;
 875                         goto out;
 876                 }
 877                 if (level == -1) {
 878                         found_owner = btrfs_ref_objectid(l, ref_item);
 879                         if (found_owner != expected_owner) {
 880                                 total_count = 2;
 881                                 goto out;
 882                         }
 883                         /*
 884                          * nasty.  we don't count a reference held by
 885                          * the running transaction.  This allows nodatacow
 886                          * to avoid cow most of the time
 887                          */
 888                         if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
 889                             btrfs_ref_generation(l, ref_item) ==
 890                             root->fs_info->generation) {
 891                                 extent_refs--;
 892                         }
 893                 }
 894                 total_count = 1;
 895                 path->slots[0]++;
 896         }
 897         /*
 898          * if there is more than one reference against a data extent,
 899          * we have to assume the other ref is another snapshot
 900          */
 901         if (level == -1 && extent_refs > 1) {
 902                 total_count = 2;
 903                 goto out;
 904         }
 905         if (cur_count == 0) {
 906                 total_count = 0;
 907                 goto out;
 908         }
 909         if (level >= 0 && root->node == count_path->nodes[level])
 910                 goto out;
 911         level++;
 912         btrfs_release_path(root, path);
 913         goto again;
 914
 915 out:
 916         btrfs_free_path(path);
 917         mutex_unlock(&root->fs_info->alloc_mutex);
 918         return total_count;
 919 }
 920
 921 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 922                   struct extent_buffer *buf)
 923 {
 924         u64 bytenr;
 925         u32 nritems;
 926         struct btrfs_key key;
 927         struct btrfs_file_extent_item *fi;
 928         int i;
 929         int level;
 930         int ret;
 931         int faili;
 932
 933         if (!root->ref_cows)
 934                 return 0;
 935
 936         mutex_lock(&root->fs_info->alloc_mutex);
 937         level = btrfs_header_level(buf);
 938         nritems = btrfs_header_nritems(buf);
 939         for (i = 0; i < nritems; i++) {
 940                 if (level == 0) {
 941                         u64 disk_bytenr;
 942                         btrfs_item_key_to_cpu(buf, &key, i);
 943                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
 944                                 continue;
 945                         fi = btrfs_item_ptr(buf, i,
 946                                             struct btrfs_file_extent_item);
 947                         if (btrfs_file_extent_type(buf, fi) ==
 948                             BTRFS_FILE_EXTENT_INLINE)
 949                                 continue;
 950                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
 951                         if (disk_bytenr == 0)
 952                                 continue;
 953                         ret = __btrfs_inc_extent_ref(trans, root, disk_bytenr,
 954                                     btrfs_file_extent_disk_num_bytes(buf, fi),
 955                                     root->root_key.objectid, trans->transid,
 956                                     key.objectid, key.offset);
 957                         if (ret) {
 958                                 faili = i;
 959                                 goto fail;
 960                         }
 961                 } else {
 962                         bytenr = btrfs_node_blockptr(buf, i);
 963                         btrfs_node_key_to_cpu(buf, &key, i);
 964                         ret = __btrfs_inc_extent_ref(trans, root, bytenr,
 965                                            btrfs_level_size(root, level - 1),
 966                                            root->root_key.objectid,
 967                                            trans->transid,
 968                                            level - 1, key.objectid);
 969                         if (ret) {
 970                                 faili = i;
 971                                 goto fail;
 972                         }
 973                 }
 974         }
 975         mutex_unlock(&root->fs_info->alloc_mutex);
 976         return 0;
 977 fail:
 978         WARN_ON(1);
 979 #if 0
 980         for (i =0; i < faili; i++) {
 981                 if (level == 0) {
 982                         u64 disk_bytenr;
 983                         btrfs_item_key_to_cpu(buf, &key, i);
 984                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
 985                                 continue;
 986                         fi = btrfs_item_ptr(buf, i,
 987                                             struct btrfs_file_extent_item);
 988                         if (btrfs_file_extent_type(buf, fi) ==
 989                             BTRFS_FILE_EXTENT_INLINE)
 990                                 continue;
 991                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
 992                         if (disk_bytenr == 0)
 993                                 continue;
 994                         err = btrfs_free_extent(trans, root, disk_bytenr,
 995                                     btrfs_file_extent_disk_num_bytes(buf,
 996                                                                       fi), 0);
 997                         BUG_ON(err);
 998                 } else {
 999                         bytenr = btrfs_node_blockptr(buf, i);
1000                         err = btrfs_free_extent(trans, root, bytenr,
1001                                         btrfs_level_size(root, level - 1), 0);
1002                         BUG_ON(err);
1003                 }
1004         }
1005 #endif
1006         mutex_unlock(&root->fs_info->alloc_mutex);
1007         return ret;
1008 }
1009
1010 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1011                                  struct btrfs_root *root,
1012                                  struct btrfs_path *path,
1013                                  struct btrfs_block_group_cache *cache)
1014 {
1015         int ret;
1016         int pending_ret;
1017         struct btrfs_root *extent_root = root->fs_info->extent_root;
1018         unsigned long bi;
1019         struct extent_buffer *leaf;
1020
1021         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1022         if (ret < 0)
1023                 goto fail;
1024         BUG_ON(ret);
1025
1026         leaf = path->nodes[0];
1027         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1028         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1029         btrfs_mark_buffer_dirty(leaf);
1030         btrfs_release_path(extent_root, path);
1031 fail:
1032         finish_current_insert(trans, extent_root);
1033         pending_ret = del_pending_extents(trans, extent_root);
1034         if (ret)
1035                 return ret;
1036         if (pending_ret)
1037                 return pending_ret;
1038         return 0;
1039
1040 }
1041
1042 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1043                                    struct btrfs_root *root)
1044 {
1045         struct extent_io_tree *block_group_cache;
1046         struct btrfs_block_group_cache *cache;
1047         int ret;
1048         int err = 0;
1049         int werr = 0;
1050         struct btrfs_path *path;
1051         u64 last = 0;
1052         u64 start;
1053         u64 end;
1054         u64 ptr;
1055
1056         block_group_cache = &root->fs_info->block_group_cache;
1057         path = btrfs_alloc_path();
1058         if (!path)
1059                 return -ENOMEM;
1060
1061         mutex_lock(&root->fs_info->alloc_mutex);
1062         while(1) {
1063                 ret = find_first_extent_bit(block_group_cache, last,
1064                                             &start, &end, BLOCK_GROUP_DIRTY);
1065                 if (ret)
1066                         break;
1067
1068                 last = end + 1;
1069                 ret = get_state_private(block_group_cache, start, &ptr);
1070                 if (ret)
1071                         break;
1072                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1073                 err = write_one_cache_group(trans, root,
1074                                             path, cache);
1075                 /*
1076                  * if we fail to write the cache group, we want
1077                  * to keep it marked dirty in hopes that a later
1078                  * write will work
1079                  */
1080                 if (err) {
1081                         werr = err;
1082                         continue;
1083                 }
1084                 clear_extent_bits(block_group_cache, start, end,
1085                                   BLOCK_GROUP_DIRTY, GFP_NOFS);
1086         }
1087         btrfs_free_path(path);
1088         mutex_unlock(&root->fs_info->alloc_mutex);
1089         return werr;
1090 }
1091
1092 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1093                                                   u64 flags)
1094 {
1095         struct list_head *head = &info->space_info;
1096         struct list_head *cur;
1097         struct btrfs_space_info *found;
1098         list_for_each(cur, head) {
1099                 found = list_entry(cur, struct btrfs_space_info, list);
1100                 if (found->flags == flags)
1101                         return found;
1102         }
1103         return NULL;
1104
1105 }
1106
1107 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1108                              u64 total_bytes, u64 bytes_used,
1109                              struct btrfs_space_info **space_info)
1110 {
1111         struct btrfs_space_info *found;
1112
1113         found = __find_space_info(info, flags);
1114         if (found) {
1115                 found->total_bytes += total_bytes;
1116                 found->bytes_used += bytes_used;
1117                 found->full = 0;
1118                 WARN_ON(found->total_bytes < found->bytes_used);
1119                 *space_info = found;
1120                 return 0;
1121         }
1122         found = kmalloc(sizeof(*found), GFP_NOFS);
1123         if (!found)
1124                 return -ENOMEM;
1125
1126         list_add(&found->list, &info->space_info);
1127         found->flags = flags;
1128         found->total_bytes = total_bytes;
1129         found->bytes_used = bytes_used;
1130         found->bytes_pinned = 0;
1131         found->full = 0;
1132         found->force_alloc = 0;
1133         *space_info = found;
1134         return 0;
1135 }
1136
1137 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1138 {
1139         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1140                                    BTRFS_BLOCK_GROUP_RAID1 |
1141                                    BTRFS_BLOCK_GROUP_RAID10 |
1142                                    BTRFS_BLOCK_GROUP_DUP);
1143         if (extra_flags) {
1144                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1145                         fs_info->avail_data_alloc_bits |= extra_flags;
1146                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1147                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1148                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1149                         fs_info->avail_system_alloc_bits |= extra_flags;
1150         }
1151 }
1152
1153 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1154 {
1155         u64 num_devices = root->fs_info->fs_devices->num_devices;
1156
1157         if (num_devices == 1)
1158                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1159         if (num_devices < 4)
1160                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1161
1162         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1163             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1164                       BTRFS_BLOCK_GROUP_RAID10))) {
1165                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1166         }
1167
1168         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1169             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1170                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1171         }
1172
1173         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1174             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1175              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1176              (flags & BTRFS_BLOCK_GROUP_DUP)))
1177                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1178         return flags;
1179 }
1180
1181 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1182                           struct btrfs_root *extent_root, u64 alloc_bytes,
1183                           u64 flags, int force)
1184 {
1185         struct btrfs_space_info *space_info;
1186         u64 thresh;
1187         u64 start;
1188         u64 num_bytes;
1189         int ret;
1190
1191         flags = reduce_alloc_profile(extent_root, flags);
1192
1193         space_info = __find_space_info(extent_root->fs_info, flags);
1194         if (!space_info) {
1195                 ret = update_space_info(extent_root->fs_info, flags,
1196                                         0, 0, &space_info);
1197                 BUG_ON(ret);
1198         }
1199         BUG_ON(!space_info);
1200
1201         if (space_info->force_alloc) {
1202                 force = 1;
1203                 space_info->force_alloc = 0;
1204         }
1205         if (space_info->full)
1206                 goto out;
1207
1208         thresh = div_factor(space_info->total_bytes, 6);
1209         if (!force &&
1210            (space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1211             thresh)
1212                 goto out;
1213
1214         mutex_lock(&extent_root->fs_info->chunk_mutex);
1215         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1216         if (ret == -ENOSPC) {
1217 printk("space info full %Lu\n", flags);
1218                 space_info->full = 1;
1219                 goto out_unlock;
1220         }
1221         BUG_ON(ret);
1222
1223         ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1224                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1225         BUG_ON(ret);
1226 out_unlock:
1227         mutex_unlock(&extent_root->fs_info->chunk_mutex);
1228 out:
1229         return 0;
1230 }
1231
1232 static int update_block_group(struct btrfs_trans_handle *trans,
1233                               struct btrfs_root *root,
1234                               u64 bytenr, u64 num_bytes, int alloc,
1235                               int mark_free)
1236 {
1237         struct btrfs_block_group_cache *cache;
1238         struct btrfs_fs_info *info = root->fs_info;
1239         u64 total = num_bytes;
1240         u64 old_val;
1241         u64 byte_in_group;
1242         u64 start;
1243         u64 end;
1244
1245         while(total) {
1246                 cache = btrfs_lookup_block_group(info, bytenr);
1247                 if (!cache) {
1248                         return -1;
1249                 }
1250                 byte_in_group = bytenr - cache->key.objectid;
1251                 WARN_ON(byte_in_group > cache->key.offset);
1252                 start = cache->key.objectid;
1253                 end = start + cache->key.offset - 1;
1254                 set_extent_bits(&info->block_group_cache, start, end,
1255                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1256
1257                 old_val = btrfs_block_group_used(&cache->item);
1258                 num_bytes = min(total, cache->key.offset - byte_in_group);
1259                 if (alloc) {
1260                         old_val += num_bytes;
1261                         cache->space_info->bytes_used += num_bytes;
1262                 } else {
1263                         old_val -= num_bytes;
1264                         cache->space_info->bytes_used -= num_bytes;
1265                         if (mark_free) {
1266                                 set_extent_dirty(&info->free_space_cache,
1267                                                  bytenr, bytenr + num_bytes - 1,
1268                                                  GFP_NOFS);
1269                         }
1270                 }
1271                 btrfs_set_block_group_used(&cache->item, old_val);
1272                 total -= num_bytes;
1273                 bytenr += num_bytes;
1274         }
1275         return 0;
1276 }
1277
1278 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1279 {
1280         u64 start;
1281         u64 end;
1282         int ret;
1283         ret = find_first_extent_bit(&root->fs_info->block_group_cache,
1284                                     search_start, &start, &end,
1285                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
1286                                     BLOCK_GROUP_SYSTEM);
1287         if (ret)
1288                 return 0;
1289         return start;
1290 }
1291
1292
1293 static int update_pinned_extents(struct btrfs_root *root,
1294                                 u64 bytenr, u64 num, int pin)
1295 {
1296         u64 len;
1297         struct btrfs_block_group_cache *cache;
1298         struct btrfs_fs_info *fs_info = root->fs_info;
1299
1300         if (pin) {
1301                 set_extent_dirty(&fs_info->pinned_extents,
1302                                 bytenr, bytenr + num - 1, GFP_NOFS);
1303         } else {
1304                 clear_extent_dirty(&fs_info->pinned_extents,
1305                                 bytenr, bytenr + num - 1, GFP_NOFS);
1306         }
1307         while (num > 0) {
1308                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1309                 if (!cache) {
1310                         u64 first = first_logical_byte(root, bytenr);
1311                         WARN_ON(first < bytenr);
1312                         len = min(first - bytenr, num);
1313                 } else {
1314                         len = min(num, cache->key.offset -
1315                                   (bytenr - cache->key.objectid));
1316                 }
1317                 if (pin) {
1318                         if (cache) {
1319                                 cache->pinned += len;
1320                                 cache->space_info->bytes_pinned += len;
1321                         }
1322                         fs_info->total_pinned += len;
1323                 } else {
1324                         if (cache) {
1325                                 cache->pinned -= len;
1326                                 cache->space_info->bytes_pinned -= len;
1327                         }
1328                         fs_info->total_pinned -= len;
1329                 }
1330                 bytenr += len;
1331                 num -= len;
1332         }
1333         return 0;
1334 }
1335
1336 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1337 {
1338         u64 last = 0;
1339         u64 start;
1340         u64 end;
1341         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1342         int ret;
1343
1344         while(1) {
1345                 ret = find_first_extent_bit(pinned_extents, last,
1346                                             &start, &end, EXTENT_DIRTY);
1347                 if (ret)
1348                         break;
1349                 set_extent_dirty(copy, start, end, GFP_NOFS);
1350                 last = end + 1;
1351         }
1352         return 0;
1353 }
1354
1355 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1356                                struct btrfs_root *root,
1357                                struct extent_io_tree *unpin)
1358 {
1359         u64 start;
1360         u64 end;
1361         int ret;
1362         struct extent_io_tree *free_space_cache;
1363         free_space_cache = &root->fs_info->free_space_cache;
1364
1365         mutex_lock(&root->fs_info->alloc_mutex);
1366         while(1) {
1367                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1368                                             EXTENT_DIRTY);
1369                 if (ret)
1370                         break;
1371                 update_pinned_extents(root, start, end + 1 - start, 0);
1372                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1373                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1374         }
1375         mutex_unlock(&root->fs_info->alloc_mutex);
1376         return 0;
1377 }
1378
1379 static int finish_current_insert(struct btrfs_trans_handle *trans,
1380                                  struct btrfs_root *extent_root)
1381 {
1382         u64 start;
1383         u64 end;
1384         struct btrfs_fs_info *info = extent_root->fs_info;
1385         struct extent_buffer *eb;
1386         struct btrfs_path *path;
1387         struct btrfs_key ins;
1388         struct btrfs_disk_key first;
1389         struct btrfs_extent_item extent_item;
1390         int ret;
1391         int level;
1392         int err = 0;
1393
1394         btrfs_set_stack_extent_refs(&extent_item, 1);
1395         btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1396         path = btrfs_alloc_path();
1397
1398         while(1) {
1399                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1400                                             &end, EXTENT_LOCKED);
1401                 if (ret)
1402                         break;
1403
1404                 ins.objectid = start;
1405                 ins.offset = end + 1 - start;
1406                 err = btrfs_insert_item(trans, extent_root, &ins,
1407                                         &extent_item, sizeof(extent_item));
1408                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1409                                   GFP_NOFS);
1410                 eb = read_tree_block(extent_root, ins.objectid, ins.offset,
1411                                      trans->transid);
1412                 btrfs_tree_lock(eb);
1413                 level = btrfs_header_level(eb);
1414                 if (level == 0) {
1415                         btrfs_item_key(eb, &first, 0);
1416                 } else {
1417                         btrfs_node_key(eb, &first, 0);
1418                 }
1419                 btrfs_tree_unlock(eb);
1420                 free_extent_buffer(eb);
1421                 /*
1422                  * the first key is just a hint, so the race we've created
1423                  * against reading it is fine
1424                  */
1425                 err = btrfs_insert_extent_backref(trans, extent_root, path,
1426                                           start, extent_root->root_key.objectid,
1427                                           0, level,
1428                                           btrfs_disk_key_objectid(&first));
1429                 BUG_ON(err);
1430         }
1431         btrfs_free_path(path);
1432         return 0;
1433 }
1434
1435 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1436                           int pending)
1437 {
1438         int err = 0;
1439
1440         if (!pending) {
1441 #if 0
1442                 struct extent_buffer *buf;
1443                 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1444                 if (buf) {
1445                         if (!btrfs_try_tree_lock(buf) &&
1446                             btrfs_buffer_uptodate(buf, 0)) {
1447                                 u64 transid =
1448                                     root->fs_info->running_transaction->transid;
1449                                 u64 header_transid =
1450                                         btrfs_header_generation(buf);
1451                                 if (header_transid == transid &&
1452                                     !btrfs_header_flag(buf,
1453                                                BTRFS_HEADER_FLAG_WRITTEN)) {
1454                                         clean_tree_block(NULL, root, buf);
1455                                         btrfs_tree_unlock(buf);
1456                                         free_extent_buffer(buf);
1457                                         return 1;
1458                                 }
1459                                 btrfs_tree_unlock(buf);
1460                         }
1461                         free_extent_buffer(buf);
1462                 }
1463 #endif
1464                 update_pinned_extents(root, bytenr, num_bytes, 1);
1465         } else {
1466                 set_extent_bits(&root->fs_info->pending_del,
1467                                 bytenr, bytenr + num_bytes - 1,
1468                                 EXTENT_LOCKED, GFP_NOFS);
1469         }
1470         BUG_ON(err < 0);
1471         return 0;
1472 }
1473
1474 /*
1475  * remove an extent from the root, returns 0 on success
1476  */
1477 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1478                          *root, u64 bytenr, u64 num_bytes,
1479                          u64 root_objectid, u64 ref_generation,
1480                          u64 owner_objectid, u64 owner_offset, int pin,
1481                          int mark_free)
1482 {
1483         struct btrfs_path *path;
1484         struct btrfs_key key;
1485         struct btrfs_fs_info *info = root->fs_info;
1486         struct btrfs_root *extent_root = info->extent_root;
1487         struct extent_buffer *leaf;
1488         int ret;
1489         int extent_slot = 0;
1490         int found_extent = 0;
1491         int num_to_del = 1;
1492         struct btrfs_extent_item *ei;
1493         u32 refs;
1494
1495         key.objectid = bytenr;
1496         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1497         key.offset = num_bytes;
1498         path = btrfs_alloc_path();
1499         if (!path)
1500                 return -ENOMEM;
1501
1502         path->reada = 1;
1503         ret = lookup_extent_backref(trans, extent_root, path,
1504                                     bytenr, root_objectid,
1505                                     ref_generation,
1506                                     owner_objectid, owner_offset, 1);
1507         if (ret == 0) {
1508                 struct btrfs_key found_key;
1509                 extent_slot = path->slots[0];
1510                 while(extent_slot > 0) {
1511                         extent_slot--;
1512                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1513                                               extent_slot);
1514                         if (found_key.objectid != bytenr)
1515                                 break;
1516                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1517                             found_key.offset == num_bytes) {
1518                                 found_extent = 1;
1519                                 break;
1520                         }
1521                         if (path->slots[0] - extent_slot > 5)
1522                                 break;
1523                 }
1524                 if (!found_extent)
1525                         ret = btrfs_del_item(trans, extent_root, path);
1526         } else {
1527                 btrfs_print_leaf(extent_root, path->nodes[0]);
1528                 WARN_ON(1);
1529                 printk("Unable to find ref byte nr %Lu root %Lu "
1530                        " gen %Lu owner %Lu offset %Lu\n", bytenr,
1531                        root_objectid, ref_generation, owner_objectid,
1532                        owner_offset);
1533         }
1534         if (!found_extent) {
1535                 btrfs_release_path(extent_root, path);
1536                 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1537                 if (ret < 0)
1538                         return ret;
1539                 BUG_ON(ret);
1540                 extent_slot = path->slots[0];
1541         }
1542
1543         leaf = path->nodes[0];
1544         ei = btrfs_item_ptr(leaf, extent_slot,
1545                             struct btrfs_extent_item);
1546         refs = btrfs_extent_refs(leaf, ei);
1547         BUG_ON(refs == 0);
1548         refs -= 1;
1549         btrfs_set_extent_refs(leaf, ei, refs);
1550
1551         btrfs_mark_buffer_dirty(leaf);
1552
1553         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1554                 /* if the back ref and the extent are next to each other
1555                  * they get deleted below in one shot
1556                  */
1557                 path->slots[0] = extent_slot;
1558                 num_to_del = 2;
1559         } else if (found_extent) {
1560                 /* otherwise delete the extent back ref */
1561                 ret = btrfs_del_item(trans, extent_root, path);
1562                 BUG_ON(ret);
1563                 /* if refs are 0, we need to setup the path for deletion */
1564                 if (refs == 0) {
1565                         btrfs_release_path(extent_root, path);
1566                         ret = btrfs_search_slot(trans, extent_root, &key, path,
1567                                                 -1, 1);
1568                         if (ret < 0)
1569                                 return ret;
1570                         BUG_ON(ret);
1571                 }
1572         }
1573
1574         if (refs == 0) {
1575                 u64 super_used;
1576                 u64 root_used;
1577
1578                 if (pin) {
1579                         ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1580                         if (ret > 0)
1581                                 mark_free = 1;
1582                         BUG_ON(ret < 0);
1583                 }
1584
1585                 /* block accounting for super block */
1586                 spin_lock_irq(&info->delalloc_lock);
1587                 super_used = btrfs_super_bytes_used(&info->super_copy);
1588                 btrfs_set_super_bytes_used(&info->super_copy,
1589                                            super_used - num_bytes);
1590                 spin_unlock_irq(&info->delalloc_lock);
1591
1592                 /* block accounting for root item */
1593                 root_used = btrfs_root_used(&root->root_item);
1594                 btrfs_set_root_used(&root->root_item,
1595                                            root_used - num_bytes);
1596                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1597                                       num_to_del);
1598                 if (ret) {
1599                         return ret;
1600                 }
1601                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1602                                          mark_free);
1603                 BUG_ON(ret);
1604         }
1605         btrfs_free_path(path);
1606         finish_current_insert(trans, extent_root);
1607         return ret;
1608 }
1609
1610 /*
1611  * find all the blocks marked as pending in the radix tree and remove
1612  * them from the extent map
1613  */
1614 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1615                                btrfs_root *extent_root)
1616 {
1617         int ret;
1618         int err = 0;
1619         u64 start;
1620         u64 end;
1621         struct extent_io_tree *pending_del;
1622         struct extent_io_tree *pinned_extents;
1623
1624         pending_del = &extent_root->fs_info->pending_del;
1625         pinned_extents = &extent_root->fs_info->pinned_extents;
1626
1627         while(1) {
1628                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1629                                             EXTENT_LOCKED);
1630                 if (ret)
1631                         break;
1632                 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1633                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1634                                   GFP_NOFS);
1635                 ret = __free_extent(trans, extent_root,
1636                                      start, end + 1 - start,
1637                                      extent_root->root_key.objectid,
1638                                      0, 0, 0, 0, 0);
1639                 if (ret)
1640                         err = ret;
1641         }
1642         return err;
1643 }
1644
1645 /*
1646  * remove an extent from the root, returns 0 on success
1647  */
1648 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
1649                                struct btrfs_root *root, u64 bytenr,
1650                                u64 num_bytes, u64 root_objectid,
1651                                u64 ref_generation, u64 owner_objectid,
1652                                u64 owner_offset, int pin)
1653 {
1654         struct btrfs_root *extent_root = root->fs_info->extent_root;
1655         int pending_ret;
1656         int ret;
1657
1658         WARN_ON(num_bytes < root->sectorsize);
1659         if (!root->ref_cows)
1660                 ref_generation = 0;
1661
1662         if (root == extent_root) {
1663                 pin_down_bytes(root, bytenr, num_bytes, 1);
1664                 return 0;
1665         }
1666         ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1667                             ref_generation, owner_objectid, owner_offset,
1668                             pin, pin == 0);
1669         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1670         return ret ? ret : pending_ret;
1671 }
1672
1673 int btrfs_free_extent(struct btrfs_trans_handle *trans,
1674                       struct btrfs_root *root, u64 bytenr,
1675                       u64 num_bytes, u64 root_objectid,
1676                       u64 ref_generation, u64 owner_objectid,
1677                       u64 owner_offset, int pin)
1678 {
1679         int ret;
1680
1681         maybe_lock_mutex(root);
1682         ret = __btrfs_free_extent(trans, root, bytenr, num_bytes,
1683                                   root_objectid, ref_generation,
1684                                   owner_objectid, owner_offset, pin);
1685         maybe_unlock_mutex(root);
1686         return ret;
1687 }
1688
1689 static u64 stripe_align(struct btrfs_root *root, u64 val)
1690 {
1691         u64 mask = ((u64)root->stripesize - 1);
1692         u64 ret = (val + mask) & ~mask;
1693         return ret;
1694 }
1695
1696 /*
1697  * walks the btree of allocated extents and find a hole of a given size.
1698  * The key ins is changed to record the hole:
1699  * ins->objectid == block start
1700  * ins->flags = BTRFS_EXTENT_ITEM_KEY
1701  * ins->offset == number of blocks
1702  * Any available blocks before search_start are skipped.
1703  */
1704 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1705                                      struct btrfs_root *orig_root,
1706                                      u64 num_bytes, u64 empty_size,
1707                                      u64 search_start, u64 search_end,
1708                                      u64 hint_byte, struct btrfs_key *ins,
1709                                      u64 exclude_start, u64 exclude_nr,
1710                                      int data)
1711 {
1712         int ret;
1713         u64 orig_search_start;
1714         struct btrfs_root * root = orig_root->fs_info->extent_root;
1715         struct btrfs_fs_info *info = root->fs_info;
1716         u64 total_needed = num_bytes;
1717         u64 *last_ptr = NULL;
1718         struct btrfs_block_group_cache *block_group;
1719         int full_scan = 0;
1720         int wrapped = 0;
1721         int chunk_alloc_done = 0;
1722         int empty_cluster = 2 * 1024 * 1024;
1723         int allowed_chunk_alloc = 0;
1724
1725         WARN_ON(num_bytes < root->sectorsize);
1726         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1727
1728         if (orig_root->ref_cows || empty_size)
1729                 allowed_chunk_alloc = 1;
1730
1731         if (data & BTRFS_BLOCK_GROUP_METADATA) {
1732                 last_ptr = &root->fs_info->last_alloc;
1733                 empty_cluster = 256 * 1024;
1734         }
1735
1736         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
1737                 last_ptr = &root->fs_info->last_data_alloc;
1738         }
1739
1740         if (last_ptr) {
1741                 if (*last_ptr)
1742                         hint_byte = *last_ptr;
1743                 else {
1744                         empty_size += empty_cluster;
1745                 }
1746         }
1747
1748         search_start = max(search_start, first_logical_byte(root, 0));
1749         orig_search_start = search_start;
1750
1751         if (search_end == (u64)-1)
1752                 search_end = btrfs_super_total_bytes(&info->super_copy);
1753
1754         if (hint_byte) {
1755                 block_group = btrfs_lookup_first_block_group(info, hint_byte);
1756                 if (!block_group)
1757                         hint_byte = search_start;
1758                 block_group = __btrfs_find_block_group(root, block_group,
1759                                                      hint_byte, data, 1);
1760                 if (last_ptr && *last_ptr == 0 && block_group)
1761                         hint_byte = block_group->key.objectid;
1762         } else {
1763                 block_group = __btrfs_find_block_group(root,
1764                                                      trans->block_group,
1765                                                      search_start, data, 1);
1766         }
1767         search_start = max(search_start, hint_byte);
1768
1769         total_needed += empty_size;
1770
1771 check_failed:
1772         if (!block_group) {
1773                 block_group = btrfs_lookup_first_block_group(info,
1774                                                              search_start);
1775                 if (!block_group)
1776                         block_group = btrfs_lookup_first_block_group(info,
1777                                                        orig_search_start);
1778         }
1779         if (full_scan && !chunk_alloc_done) {
1780                 if (allowed_chunk_alloc) {
1781                         do_chunk_alloc(trans, root,
1782                                      num_bytes + 2 * 1024 * 1024, data, 1);
1783                         allowed_chunk_alloc = 0;
1784                 } else if (block_group && block_group_bits(block_group, data)) {
1785                         block_group->space_info->force_alloc = 1;
1786                 }
1787                 chunk_alloc_done = 1;
1788         }
1789         ret = find_search_start(root, &block_group, &search_start,
1790                                 total_needed, data);
1791         if (ret == -ENOSPC && last_ptr && *last_ptr) {
1792                 *last_ptr = 0;
1793                 block_group = btrfs_lookup_first_block_group(info,
1794                                                              orig_search_start);
1795                 search_start = orig_search_start;
1796                 ret = find_search_start(root, &block_group, &search_start,
1797                                         total_needed, data);
1798         }
1799         if (ret == -ENOSPC)
1800                 goto enospc;
1801         if (ret)
1802                 goto error;
1803
1804         if (last_ptr && *last_ptr && search_start != *last_ptr) {
1805                 *last_ptr = 0;
1806                 if (!empty_size) {
1807                         empty_size += empty_cluster;
1808                         total_needed += empty_size;
1809                 }
1810                 block_group = btrfs_lookup_first_block_group(info,
1811                                                        orig_search_start);
1812                 search_start = orig_search_start;
1813                 ret = find_search_start(root, &block_group,
1814                                         &search_start, total_needed, data);
1815                 if (ret == -ENOSPC)
1816                         goto enospc;
1817                 if (ret)
1818                         goto error;
1819         }
1820
1821         search_start = stripe_align(root, search_start);
1822         ins->objectid = search_start;
1823         ins->offset = num_bytes;
1824
1825         if (ins->objectid + num_bytes >= search_end)
1826                 goto enospc;
1827
1828         if (ins->objectid + num_bytes >
1829             block_group->key.objectid + block_group->key.offset) {
1830                 search_start = block_group->key.objectid +
1831                         block_group->key.offset;
1832                 goto new_group;
1833         }
1834
1835         if (test_range_bit(&info->extent_ins, ins->objectid,
1836                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1837                 search_start = ins->objectid + num_bytes;
1838                 goto new_group;
1839         }
1840
1841         if (test_range_bit(&info->pinned_extents, ins->objectid,
1842                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1843                 search_start = ins->objectid + num_bytes;
1844                 goto new_group;
1845         }
1846
1847         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1848             ins->objectid < exclude_start + exclude_nr)) {
1849                 search_start = exclude_start + exclude_nr;
1850                 goto new_group;
1851         }
1852
1853         if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1854                 block_group = btrfs_lookup_block_group(info, ins->objectid);
1855                 if (block_group)
1856                         trans->block_group = block_group;
1857         }
1858         ins->offset = num_bytes;
1859         if (last_ptr) {
1860                 *last_ptr = ins->objectid + ins->offset;
1861                 if (*last_ptr ==
1862                     btrfs_super_total_bytes(&root->fs_info->super_copy)) {
1863                         *last_ptr = 0;
1864                 }
1865         }
1866         return 0;
1867
1868 new_group:
1869         if (search_start + num_bytes >= search_end) {
1870 enospc:
1871                 search_start = orig_search_start;
1872                 if (full_scan) {
1873                         ret = -ENOSPC;
1874                         goto error;
1875                 }
1876                 if (wrapped) {
1877                         if (!full_scan)
1878                                 total_needed -= empty_size;
1879                         full_scan = 1;
1880                 } else
1881                         wrapped = 1;
1882         }
1883         block_group = btrfs_lookup_first_block_group(info, search_start);
1884         cond_resched();
1885         block_group = __btrfs_find_block_group(root, block_group,
1886                                              search_start, data, 0);
1887         goto check_failed;
1888
1889 error:
1890         return ret;
1891 }
1892
1893 /*
1894  * finds a free extent and does all the dirty work required for allocation
1895  * returns the key for the extent through ins, and a tree buffer for
1896  * the first block of the extent through buf.
1897  *
1898  * returns 0 if everything worked, non-zero otherwise.
1899  */
1900 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1901                        struct btrfs_root *root,
1902                        u64 num_bytes, u64 min_alloc_size,
1903                        u64 root_objectid, u64 ref_generation,
1904                        u64 owner, u64 owner_offset,
1905                        u64 empty_size, u64 hint_byte,
1906                        u64 search_end, struct btrfs_key *ins, u64 data)
1907 {
1908         int ret;
1909         int pending_ret;
1910         u64 super_used;
1911         u64 root_used;
1912         u64 search_start = 0;
1913         u64 alloc_profile;
1914         u32 sizes[2];
1915         struct btrfs_fs_info *info = root->fs_info;
1916         struct btrfs_root *extent_root = info->extent_root;
1917         struct btrfs_extent_item *extent_item;
1918         struct btrfs_extent_ref *ref;
1919         struct btrfs_path *path;
1920         struct btrfs_key keys[2];
1921
1922         maybe_lock_mutex(root);
1923
1924         if (data) {
1925                 alloc_profile = info->avail_data_alloc_bits &
1926                                 info->data_alloc_profile;
1927                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1928         } else if (root == root->fs_info->chunk_root) {
1929                 alloc_profile = info->avail_system_alloc_bits &
1930                                 info->system_alloc_profile;
1931                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1932         } else {
1933                 alloc_profile = info->avail_metadata_alloc_bits &
1934                                 info->metadata_alloc_profile;
1935                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1936         }
1937 again:
1938         data = reduce_alloc_profile(root, data);
1939         /*
1940          * the only place that sets empty_size is btrfs_realloc_node, which
1941          * is not called recursively on allocations
1942          */
1943         if (empty_size || root->ref_cows) {
1944                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1945                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1946                                      2 * 1024 * 1024,
1947                                      BTRFS_BLOCK_GROUP_METADATA |
1948                                      (info->metadata_alloc_profile &
1949                                       info->avail_metadata_alloc_bits), 0);
1950                         BUG_ON(ret);
1951                 }
1952                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1953                                      num_bytes + 2 * 1024 * 1024, data, 0);
1954                 BUG_ON(ret);
1955         }
1956
1957         WARN_ON(num_bytes < root->sectorsize);
1958         ret = find_free_extent(trans, root, num_bytes, empty_size,
1959                                search_start, search_end, hint_byte, ins,
1960                                trans->alloc_exclude_start,
1961                                trans->alloc_exclude_nr, data);
1962
1963         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
1964                 num_bytes = num_bytes >> 1;
1965                 num_bytes = max(num_bytes, min_alloc_size);
1966                 do_chunk_alloc(trans, root->fs_info->extent_root,
1967                                num_bytes, data, 1);
1968                 goto again;
1969         }
1970         if (ret) {
1971                 printk("allocation failed flags %Lu\n", data);
1972         }
1973         if (ret) {
1974                 BUG();
1975                 goto out;
1976         }
1977
1978         /* block accounting for super block */
1979         spin_lock_irq(&info->delalloc_lock);
1980         super_used = btrfs_super_bytes_used(&info->super_copy);
1981         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1982         spin_unlock_irq(&info->delalloc_lock);
1983
1984         /* block accounting for root item */
1985         root_used = btrfs_root_used(&root->root_item);
1986         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1987
1988         clear_extent_dirty(&root->fs_info->free_space_cache,
1989                            ins->objectid, ins->objectid + ins->offset - 1,
1990                            GFP_NOFS);
1991
1992         if (root == extent_root) {
1993                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1994                                 ins->objectid + ins->offset - 1,
1995                                 EXTENT_LOCKED, GFP_NOFS);
1996                 goto update_block;
1997         }
1998
1999         WARN_ON(trans->alloc_exclude_nr);
2000         trans->alloc_exclude_start = ins->objectid;
2001         trans->alloc_exclude_nr = ins->offset;
2002
2003         memcpy(&keys[0], ins, sizeof(*ins));
2004         keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
2005                                          owner, owner_offset);
2006         keys[1].objectid = ins->objectid;
2007         keys[1].type = BTRFS_EXTENT_REF_KEY;
2008         sizes[0] = sizeof(*extent_item);
2009         sizes[1] = sizeof(*ref);
2010
2011         path = btrfs_alloc_path();
2012         BUG_ON(!path);
2013
2014         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2015                                        sizes, 2);
2016
2017         BUG_ON(ret);
2018         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2019                                      struct btrfs_extent_item);
2020         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
2021         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2022                              struct btrfs_extent_ref);
2023
2024         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2025         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2026         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2027         btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
2028
2029         btrfs_mark_buffer_dirty(path->nodes[0]);
2030
2031         trans->alloc_exclude_start = 0;
2032         trans->alloc_exclude_nr = 0;
2033         btrfs_free_path(path);
2034         finish_current_insert(trans, extent_root);
2035         pending_ret = del_pending_extents(trans, extent_root);
2036
2037         if (ret)
2038                 goto out;
2039         if (pending_ret) {
2040                 ret = pending_ret;
2041                 goto out;
2042         }
2043
2044 update_block:
2045         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
2046         if (ret) {
2047                 printk("update block group failed for %Lu %Lu\n",
2048                        ins->objectid, ins->offset);
2049                 BUG();
2050         }
2051 out:
2052         maybe_unlock_mutex(root);
2053         return ret;
2054 }
2055 /*
2056  * helper function to allocate a block for a given tree
2057  * returns the tree buffer or NULL.
2058  */
2059 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2060                                              struct btrfs_root *root,
2061                                              u32 blocksize,
2062                                              u64 root_objectid,
2063                                              u64 ref_generation,
2064                                              u64 first_objectid,
2065                                              int level,
2066                                              u64 hint,
2067                                              u64 empty_size)
2068 {
2069         struct btrfs_key ins;
2070         int ret;
2071         struct extent_buffer *buf;
2072
2073         ret = btrfs_alloc_extent(trans, root, blocksize, blocksize,
2074                                  root_objectid, ref_generation,
2075                                  level, first_objectid, empty_size, hint,
2076                                  (u64)-1, &ins, 0);
2077         if (ret) {
2078                 BUG_ON(ret > 0);
2079                 return ERR_PTR(ret);
2080         }
2081         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2082         if (!buf) {
2083                 btrfs_free_extent(trans, root, ins.objectid, blocksize,
2084                                   root->root_key.objectid, ref_generation,
2085                                   0, 0, 0);
2086                 return ERR_PTR(-ENOMEM);
2087         }
2088         btrfs_set_header_generation(buf, trans->transid);
2089         btrfs_tree_lock(buf);
2090         clean_tree_block(trans, root, buf);
2091         btrfs_set_buffer_uptodate(buf);
2092
2093         if (PageDirty(buf->first_page)) {
2094                 printk("page %lu dirty\n", buf->first_page->index);
2095                 WARN_ON(1);
2096         }
2097
2098         set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2099                          buf->start + buf->len - 1, GFP_NOFS);
2100         if (!btrfs_test_opt(root, SSD))
2101                 btrfs_set_buffer_defrag(buf);
2102         trans->blocks_used++;
2103         return buf;
2104 }
2105
2106 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2107                                   struct btrfs_root *root,
2108                                   struct extent_buffer *leaf)
2109 {
2110         u64 leaf_owner;
2111         u64 leaf_generation;
2112         struct btrfs_key key;
2113         struct btrfs_file_extent_item *fi;
2114         int i;
2115         int nritems;
2116         int ret;
2117
2118         BUG_ON(!btrfs_is_leaf(leaf));
2119         nritems = btrfs_header_nritems(leaf);
2120         leaf_owner = btrfs_header_owner(leaf);
2121         leaf_generation = btrfs_header_generation(leaf);
2122
2123         for (i = 0; i < nritems; i++) {
2124                 u64 disk_bytenr;
2125
2126                 btrfs_item_key_to_cpu(leaf, &key, i);
2127                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2128                         continue;
2129                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2130                 if (btrfs_file_extent_type(leaf, fi) ==
2131                     BTRFS_FILE_EXTENT_INLINE)
2132                         continue;
2133                 /*
2134                  * FIXME make sure to insert a trans record that
2135                  * repeats the snapshot del on crash
2136                  */
2137                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2138                 if (disk_bytenr == 0)
2139                         continue;
2140                 ret = __btrfs_free_extent(trans, root, disk_bytenr,
2141                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2142                                 leaf_owner, leaf_generation,
2143                                 key.objectid, key.offset, 0);
2144                 BUG_ON(ret);
2145         }
2146         return 0;
2147 }
2148
2149 static void noinline reada_walk_down(struct btrfs_root *root,
2150                                      struct extent_buffer *node,
2151                                      int slot)
2152 {
2153         u64 bytenr;
2154         u64 last = 0;
2155         u32 nritems;
2156         u32 refs;
2157         u32 blocksize;
2158         int ret;
2159         int i;
2160         int level;
2161         int skipped = 0;
2162
2163         nritems = btrfs_header_nritems(node);
2164         level = btrfs_header_level(node);
2165         if (level)
2166                 return;
2167
2168         for (i = slot; i < nritems && skipped < 32; i++) {
2169                 bytenr = btrfs_node_blockptr(node, i);
2170                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2171                              (last > bytenr && last - bytenr > 32 * 1024))) {
2172                         skipped++;
2173                         continue;
2174                 }
2175                 blocksize = btrfs_level_size(root, level - 1);
2176                 if (i != slot) {
2177                         ret = lookup_extent_ref(NULL, root, bytenr,
2178                                                 blocksize, &refs);
2179                         BUG_ON(ret);
2180                         if (refs != 1) {
2181                                 skipped++;
2182                                 continue;
2183                         }
2184                 }
2185                 ret = readahead_tree_block(root, bytenr, blocksize,
2186                                            btrfs_node_ptr_generation(node, i));
2187                 last = bytenr + blocksize;
2188                 cond_resched();
2189                 if (ret)
2190                         break;
2191         }
2192 }
2193
2194 /*
2195  * we want to avoid as much random IO as we can with the alloc mutex
2196  * held, so drop the lock and do the lookup, then do it again with the
2197  * lock held.
2198  */
2199 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
2200                               u32 *refs)
2201 {
2202         mutex_unlock(&root->fs_info->alloc_mutex);
2203         lookup_extent_ref(NULL, root, start, len, refs);
2204         cond_resched();
2205         mutex_lock(&root->fs_info->alloc_mutex);
2206         return lookup_extent_ref(NULL, root, start, len, refs);
2207 }
2208
2209 /*
2210  * helper function for drop_snapshot, this walks down the tree dropping ref
2211  * counts as it goes.
2212  */
2213 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2214                                    struct btrfs_root *root,
2215                                    struct btrfs_path *path, int *level)
2216 {
2217         u64 root_owner;
2218         u64 root_gen;
2219         u64 bytenr;
2220         u64 ptr_gen;
2221         struct extent_buffer *next;
2222         struct extent_buffer *cur;
2223         struct extent_buffer *parent;
2224         u32 blocksize;
2225         int ret;
2226         u32 refs;
2227
2228         mutex_lock(&root->fs_info->alloc_mutex);
2229
2230         WARN_ON(*level < 0);
2231         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2232         ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
2233                                 path->nodes[*level]->len, &refs);
2234         BUG_ON(ret);
2235         if (refs > 1)
2236                 goto out;
2237
2238         /*
2239          * walk down to the last node level and free all the leaves
2240          */
2241         while(*level >= 0) {
2242                 WARN_ON(*level < 0);
2243                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2244                 cur = path->nodes[*level];
2245
2246                 if (btrfs_header_level(cur) != *level)
2247                         WARN_ON(1);
2248
2249                 if (path->slots[*level] >=
2250                     btrfs_header_nritems(cur))
2251                         break;
2252                 if (*level == 0) {
2253                         ret = drop_leaf_ref(trans, root, cur);
2254                         BUG_ON(ret);
2255                         break;
2256                 }
2257                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2258                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2259                 blocksize = btrfs_level_size(root, *level - 1);
2260
2261                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
2262                 BUG_ON(ret);
2263                 if (refs != 1) {
2264                         parent = path->nodes[*level];
2265                         root_owner = btrfs_header_owner(parent);
2266                         root_gen = btrfs_header_generation(parent);
2267                         path->slots[*level]++;
2268                         ret = __btrfs_free_extent(trans, root, bytenr,
2269                                                 blocksize, root_owner,
2270                                                 root_gen, 0, 0, 1);
2271                         BUG_ON(ret);
2272                         continue;
2273                 }
2274                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2275                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2276                         free_extent_buffer(next);
2277                         mutex_unlock(&root->fs_info->alloc_mutex);
2278
2279                         if (path->slots[*level] == 0)
2280                                 reada_walk_down(root, cur, path->slots[*level]);
2281
2282                         next = read_tree_block(root, bytenr, blocksize,
2283                                                ptr_gen);
2284                         cond_resched();
2285                         mutex_lock(&root->fs_info->alloc_mutex);
2286
2287                         /* we've dropped the lock, double check */
2288                         ret = drop_snap_lookup_refcount(root, bytenr,
2289                                                 blocksize, &refs);
2290                         BUG_ON(ret);
2291                         if (refs != 1) {
2292                                 parent = path->nodes[*level];
2293                                 root_owner = btrfs_header_owner(parent);
2294                                 root_gen = btrfs_header_generation(parent);
2295
2296                                 path->slots[*level]++;
2297                                 free_extent_buffer(next);
2298                                 ret = __btrfs_free_extent(trans, root, bytenr,
2299                                                         blocksize,
2300                                                         root_owner,
2301                                                         root_gen, 0, 0, 1);
2302                                 BUG_ON(ret);
2303                                 continue;
2304                         }
2305                 }
2306                 WARN_ON(*level <= 0);
2307                 if (path->nodes[*level-1])
2308                         free_extent_buffer(path->nodes[*level-1]);
2309                 path->nodes[*level-1] = next;
2310                 *level = btrfs_header_level(next);
2311                 path->slots[*level] = 0;
2312         }
2313 out:
2314         WARN_ON(*level < 0);
2315         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2316
2317         if (path->nodes[*level] == root->node) {
2318                 root_owner = root->root_key.objectid;
2319                 parent = path->nodes[*level];
2320         } else {
2321                 parent = path->nodes[*level + 1];
2322                 root_owner = btrfs_header_owner(parent);
2323         }
2324
2325         root_gen = btrfs_header_generation(parent);
2326         ret = __btrfs_free_extent(trans, root, path->nodes[*level]->start,
2327                                 path->nodes[*level]->len,
2328                                 root_owner, root_gen, 0, 0, 1);
2329         free_extent_buffer(path->nodes[*level]);
2330         path->nodes[*level] = NULL;
2331         *level += 1;
2332         BUG_ON(ret);
2333         mutex_unlock(&root->fs_info->alloc_mutex);
2334         cond_resched();
2335         return 0;
2336 }
2337
2338 /*
2339  * helper for dropping snapshots.  This walks back up the tree in the path
2340  * to find the first node higher up where we haven't yet gone through
2341  * all the slots
2342  */
2343 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2344                                  struct btrfs_root *root,
2345                                  struct btrfs_path *path, int *level)
2346 {
2347         u64 root_owner;
2348         u64 root_gen;
2349         struct btrfs_root_item *root_item = &root->root_item;
2350         int i;
2351         int slot;
2352         int ret;
2353
2354         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2355                 slot = path->slots[i];
2356                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2357                         struct extent_buffer *node;
2358                         struct btrfs_disk_key disk_key;
2359                         node = path->nodes[i];
2360                         path->slots[i]++;
2361                         *level = i;
2362                         WARN_ON(*level == 0);
2363                         btrfs_node_key(node, &disk_key, path->slots[i]);
2364                         memcpy(&root_item->drop_progress,
2365                                &disk_key, sizeof(disk_key));
2366                         root_item->drop_level = i;
2367                         return 0;
2368                 } else {
2369                         if (path->nodes[*level] == root->node) {
2370                                 root_owner = root->root_key.objectid;
2371                                 root_gen =
2372                                    btrfs_header_generation(path->nodes[*level]);
2373                         } else {
2374                                 struct extent_buffer *node;
2375                                 node = path->nodes[*level + 1];
2376                                 root_owner = btrfs_header_owner(node);
2377                                 root_gen = btrfs_header_generation(node);
2378                         }
2379                         ret = btrfs_free_extent(trans, root,
2380                                                 path->nodes[*level]->start,
2381                                                 path->nodes[*level]->len,
2382                                                 root_owner, root_gen, 0, 0, 1);
2383                         BUG_ON(ret);
2384                         free_extent_buffer(path->nodes[*level]);
2385                         path->nodes[*level] = NULL;
2386                         *level = i + 1;
2387                 }
2388         }
2389         return 1;
2390 }
2391
2392 /*
2393  * drop the reference count on the tree rooted at 'snap'.  This traverses
2394  * the tree freeing any blocks that have a ref count of zero after being
2395  * decremented.
2396  */
2397 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2398                         *root)
2399 {
2400         int ret = 0;
2401         int wret;
2402         int level;
2403         struct btrfs_path *path;
2404         int i;
2405         int orig_level;
2406         struct btrfs_root_item *root_item = &root->root_item;
2407
2408         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
2409         path = btrfs_alloc_path();
2410         BUG_ON(!path);
2411
2412         level = btrfs_header_level(root->node);
2413         orig_level = level;
2414         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2415                 path->nodes[level] = root->node;
2416                 extent_buffer_get(root->node);
2417                 path->slots[level] = 0;
2418         } else {
2419                 struct btrfs_key key;
2420                 struct btrfs_disk_key found_key;
2421                 struct extent_buffer *node;
2422
2423                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2424                 level = root_item->drop_level;
2425                 path->lowest_level = level;
2426                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2427                 if (wret < 0) {
2428                         ret = wret;
2429                         goto out;
2430                 }
2431                 node = path->nodes[level];
2432                 btrfs_node_key(node, &found_key, path->slots[level]);
2433                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2434                                sizeof(found_key)));
2435                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
2436                         if (path->nodes[i] && path->locks[i]) {
2437                                 path->locks[i] = 0;
2438                                 btrfs_tree_unlock(path->nodes[i]);
2439                         }
2440                 }
2441         }
2442         while(1) {
2443                 wret = walk_down_tree(trans, root, path, &level);
2444                 if (wret > 0)
2445                         break;
2446                 if (wret < 0)
2447                         ret = wret;
2448
2449                 wret = walk_up_tree(trans, root, path, &level);
2450                 if (wret > 0)
2451                         break;
2452                 if (wret < 0)
2453                         ret = wret;
2454                 if (trans->transaction->in_commit) {
2455                         ret = -EAGAIN;
2456                         break;
2457                 }
2458         }
2459         for (i = 0; i <= orig_level; i++) {
2460                 if (path->nodes[i]) {
2461                         free_extent_buffer(path->nodes[i]);
2462                         path->nodes[i] = NULL;
2463                 }
2464         }
2465 out:
2466         btrfs_free_path(path);
2467         return ret;
2468 }
2469
2470 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2471 {
2472         u64 start;
2473         u64 end;
2474         u64 ptr;
2475         int ret;
2476
2477         mutex_lock(&info->alloc_mutex);
2478         while(1) {
2479                 ret = find_first_extent_bit(&info->block_group_cache, 0,
2480                                             &start, &end, (unsigned int)-1);
2481                 if (ret)
2482                         break;
2483                 ret = get_state_private(&info->block_group_cache, start, &ptr);
2484                 if (!ret)
2485                         kfree((void *)(unsigned long)ptr);
2486                 clear_extent_bits(&info->block_group_cache, start,
2487                                   end, (unsigned int)-1, GFP_NOFS);
2488         }
2489         while(1) {
2490                 ret = find_first_extent_bit(&info->free_space_cache, 0,
2491                                             &start, &end, EXTENT_DIRTY);
2492                 if (ret)
2493                         break;
2494                 clear_extent_dirty(&info->free_space_cache, start,
2495                                    end, GFP_NOFS);
2496         }
2497         mutex_unlock(&info->alloc_mutex);
2498         return 0;
2499 }
2500
2501 static unsigned long calc_ra(unsigned long start, unsigned long last,
2502                              unsigned long nr)
2503 {
2504         return min(last, start + nr - 1);
2505 }
2506
2507 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
2508                                          u64 len)
2509 {
2510         u64 page_start;
2511         u64 page_end;
2512         unsigned long last_index;
2513         unsigned long i;
2514         struct page *page;
2515         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2516         struct file_ra_state *ra;
2517         unsigned long total_read = 0;
2518         unsigned long ra_pages;
2519         struct btrfs_trans_handle *trans;
2520
2521         ra = kzalloc(sizeof(*ra), GFP_NOFS);
2522
2523         mutex_lock(&inode->i_mutex);
2524         i = start >> PAGE_CACHE_SHIFT;
2525         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
2526
2527         ra_pages = BTRFS_I(inode)->root->fs_info->bdi.ra_pages;
2528
2529         file_ra_state_init(ra, inode->i_mapping);
2530
2531         for (; i <= last_index; i++) {
2532                 if (total_read % ra_pages == 0) {
2533                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
2534                                        calc_ra(i, last_index, ra_pages));
2535                 }
2536                 total_read++;
2537                 if (((u64)i << PAGE_CACHE_SHIFT) > inode->i_size)
2538                         goto truncate_racing;
2539
2540                 page = grab_cache_page(inode->i_mapping, i);
2541                 if (!page) {
2542                         goto out_unlock;
2543                 }
2544                 if (!PageUptodate(page)) {
2545                         btrfs_readpage(NULL, page);
2546                         lock_page(page);
2547                         if (!PageUptodate(page)) {
2548                                 unlock_page(page);
2549                                 page_cache_release(page);
2550                                 goto out_unlock;
2551                         }
2552                 }
2553 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
2554                 ClearPageDirty(page);
2555 #else
2556                 cancel_dirty_page(page, PAGE_CACHE_SIZE);
2557 #endif
2558                 wait_on_page_writeback(page);
2559                 set_page_extent_mapped(page);
2560                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2561                 page_end = page_start + PAGE_CACHE_SIZE - 1;
2562
2563                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
2564
2565                 set_extent_delalloc(io_tree, page_start,
2566                                     page_end, GFP_NOFS);
2567                 set_page_dirty(page);
2568
2569                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
2570                 unlock_page(page);
2571                 page_cache_release(page);
2572         }
2573         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2574                                            total_read);
2575
2576 out_unlock:
2577         kfree(ra);
2578         trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
2579         if (trans) {
2580                 btrfs_add_ordered_inode(inode);
2581                 btrfs_end_transaction(trans, BTRFS_I(inode)->root);
2582                 mark_inode_dirty(inode);
2583         }
2584         mutex_unlock(&inode->i_mutex);
2585         return 0;
2586
2587 truncate_racing:
2588         vmtruncate(inode, inode->i_size);
2589         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
2590                                            total_read);
2591         goto out_unlock;
2592 }
2593
2594 /*
2595  * The back references tell us which tree holds a ref on a block,
2596  * but it is possible for the tree root field in the reference to
2597  * reflect the original root before a snapshot was made.  In this
2598  * case we should search through all the children of a given root
2599  * to find potential holders of references on a block.
2600  *
2601  * Instead, we do something a little less fancy and just search
2602  * all the roots for a given key/block combination.
2603  */
2604 static int find_root_for_ref(struct btrfs_root *root,
2605                              struct btrfs_path *path,
2606                              struct btrfs_key *key0,
2607                              int level,
2608                              int file_key,
2609                              struct btrfs_root **found_root,
2610                              u64 bytenr)
2611 {
2612         struct btrfs_key root_location;
2613         struct btrfs_root *cur_root = *found_root;
2614         struct btrfs_file_extent_item *file_extent;
2615         u64 root_search_start = BTRFS_FS_TREE_OBJECTID;
2616         u64 found_bytenr;
2617         int ret;
2618         int i;
2619
2620         root_location.offset = (u64)-1;
2621         root_location.type = BTRFS_ROOT_ITEM_KEY;
2622         path->lowest_level = level;
2623         path->reada = 0;
2624         while(1) {
2625                 ret = btrfs_search_slot(NULL, cur_root, key0, path, 0, 0);
2626                 found_bytenr = 0;
2627                 if (ret == 0 && file_key) {
2628                         struct extent_buffer *leaf = path->nodes[0];
2629                         file_extent = btrfs_item_ptr(leaf, path->slots[0],
2630                                              struct btrfs_file_extent_item);
2631                         if (btrfs_file_extent_type(leaf, file_extent) ==
2632                             BTRFS_FILE_EXTENT_REG) {
2633                                 found_bytenr =
2634                                         btrfs_file_extent_disk_bytenr(leaf,
2635                                                                file_extent);
2636                        }
2637                 } else if (!file_key) {
2638                         if (path->nodes[level])
2639                                 found_bytenr = path->nodes[level]->start;
2640                 }
2641
2642                 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2643                         if (!path->nodes[i])
2644                                 break;
2645                         free_extent_buffer(path->nodes[i]);
2646                         path->nodes[i] = NULL;
2647                 }
2648                 btrfs_release_path(cur_root, path);
2649
2650                 if (found_bytenr == bytenr) {
2651                         *found_root = cur_root;
2652                         ret = 0;
2653                         goto out;
2654                 }
2655                 ret = btrfs_search_root(root->fs_info->tree_root,
2656                                         root_search_start, &root_search_start);
2657                 if (ret)
2658                         break;
2659
2660                 root_location.objectid = root_search_start;
2661                 cur_root = btrfs_read_fs_root_no_name(root->fs_info,
2662                                                       &root_location);
2663                 if (!cur_root) {
2664                         ret = 1;
2665                         break;
2666                 }
2667         }
2668 out:
2669         path->lowest_level = 0;
2670         return ret;
2671 }
2672
2673 /*
2674  * note, this releases the path
2675  */
2676 static int noinline relocate_one_reference(struct btrfs_root *extent_root,
2677                                   struct btrfs_path *path,
2678                                   struct btrfs_key *extent_key,
2679                                   u64 *last_file_objectid,
2680                                   u64 *last_file_offset,
2681                                   u64 *last_file_root,
2682                                   u64 last_extent)
2683 {
2684         struct inode *inode;
2685         struct btrfs_root *found_root;
2686         struct btrfs_key root_location;
2687         struct btrfs_key found_key;
2688         struct btrfs_extent_ref *ref;
2689         u64 ref_root;
2690         u64 ref_gen;
2691         u64 ref_objectid;
2692         u64 ref_offset;
2693         int ret;
2694         int level;
2695
2696         ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
2697                              struct btrfs_extent_ref);
2698         ref_root = btrfs_ref_root(path->nodes[0], ref);
2699         ref_gen = btrfs_ref_generation(path->nodes[0], ref);
2700         ref_objectid = btrfs_ref_objectid(path->nodes[0], ref);
2701         ref_offset = btrfs_ref_offset(path->nodes[0], ref);
2702         btrfs_release_path(extent_root, path);
2703
2704         root_location.objectid = ref_root;
2705         if (ref_gen == 0)
2706                 root_location.offset = 0;
2707         else
2708                 root_location.offset = (u64)-1;
2709         root_location.type = BTRFS_ROOT_ITEM_KEY;
2710
2711         found_root = btrfs_read_fs_root_no_name(extent_root->fs_info,
2712                                                 &root_location);
2713         BUG_ON(!found_root);
2714
2715         if (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2716                 found_key.objectid = ref_objectid;
2717                 found_key.type = BTRFS_EXTENT_DATA_KEY;
2718                 found_key.offset = ref_offset;
2719                 level = 0;
2720
2721                 if (last_extent == extent_key->objectid &&
2722                     *last_file_objectid == ref_objectid &&
2723                     *last_file_offset == ref_offset &&
2724                     *last_file_root == ref_root)
2725                         goto out;
2726
2727                 ret = find_root_for_ref(extent_root, path, &found_key,
2728                                         level, 1, &found_root,
2729                                         extent_key->objectid);
2730
2731                 if (ret)
2732                         goto out;
2733
2734                 if (last_extent == extent_key->objectid &&
2735                     *last_file_objectid == ref_objectid &&
2736                     *last_file_offset == ref_offset &&
2737                     *last_file_root == ref_root)
2738                         goto out;
2739
2740                 inode = btrfs_iget_locked(extent_root->fs_info->sb,
2741                                           ref_objectid, found_root);
2742                 if (inode->i_state & I_NEW) {
2743                         /* the inode and parent dir are two different roots */
2744                         BTRFS_I(inode)->root = found_root;
2745                         BTRFS_I(inode)->location.objectid = ref_objectid;
2746                         BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
2747                         BTRFS_I(inode)->location.offset = 0;
2748                         btrfs_read_locked_inode(inode);
2749                         unlock_new_inode(inode);
2750
2751                 }
2752                 /* this can happen if the reference is not against
2753                  * the latest version of the tree root
2754                  */
2755                 if (is_bad_inode(inode)) {
2756                         goto out;
2757                 }
2758                 *last_file_objectid = inode->i_ino;
2759                 *last_file_root = found_root->root_key.objectid;
2760                 *last_file_offset = ref_offset;
2761
2762                 relocate_inode_pages(inode, ref_offset, extent_key->offset);
2763                 iput(inode);
2764         } else {
2765                 struct btrfs_trans_handle *trans;
2766                 struct extent_buffer *eb;
2767                 int i;
2768
2769                 eb = read_tree_block(found_root, extent_key->objectid,
2770                                      extent_key->offset, 0);
2771                 btrfs_tree_lock(eb);
2772                 level = btrfs_header_level(eb);
2773
2774                 if (level == 0)
2775                         btrfs_item_key_to_cpu(eb, &found_key, 0);
2776                 else
2777                         btrfs_node_key_to_cpu(eb, &found_key, 0);
2778
2779                 btrfs_tree_unlock(eb);
2780                 free_extent_buffer(eb);
2781
2782                 ret = find_root_for_ref(extent_root, path, &found_key,
2783                                         level, 0, &found_root,
2784                                         extent_key->objectid);
2785
2786                 if (ret)
2787                         goto out;
2788
2789                 trans = btrfs_start_transaction(found_root, 1);
2790
2791                 path->lowest_level = level;
2792                 path->reada = 2;
2793                 ret = btrfs_search_slot(trans, found_root, &found_key, path,
2794                                         0, 1);
2795                 path->lowest_level = 0;
2796                 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
2797                         if (!path->nodes[i])
2798                                 break;
2799                         free_extent_buffer(path->nodes[i]);
2800                         path->nodes[i] = NULL;
2801                 }
2802                 btrfs_release_path(found_root, path);
2803                 if (found_root == found_root->fs_info->extent_root)
2804                         btrfs_extent_post_op(trans, found_root);
2805                 btrfs_end_transaction(trans, found_root);
2806         }
2807
2808 out:
2809         return 0;
2810 }
2811
2812 static int noinline del_extent_zero(struct btrfs_root *extent_root,
2813                                     struct btrfs_path *path,
2814                                     struct btrfs_key *extent_key)
2815 {
2816         int ret;
2817         struct btrfs_trans_handle *trans;
2818
2819         trans = btrfs_start_transaction(extent_root, 1);
2820         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
2821         if (ret > 0) {
2822                 ret = -EIO;
2823                 goto out;
2824         }
2825         if (ret < 0)
2826                 goto out;
2827         ret = btrfs_del_item(trans, extent_root, path);
2828 out:
2829         btrfs_end_transaction(trans, extent_root);
2830         return ret;
2831 }
2832
2833 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
2834                                         struct btrfs_path *path,
2835                                         struct btrfs_key *extent_key)
2836 {
2837         struct btrfs_key key;
2838         struct btrfs_key found_key;
2839         struct extent_buffer *leaf;
2840         u64 last_file_objectid = 0;
2841         u64 last_file_root = 0;
2842         u64 last_file_offset = (u64)-1;
2843         u64 last_extent = 0;
2844         u32 nritems;
2845         u32 item_size;
2846         int ret = 0;
2847
2848         if (extent_key->objectid == 0) {
2849                 ret = del_extent_zero(extent_root, path, extent_key);
2850                 goto out;
2851         }
2852         key.objectid = extent_key->objectid;
2853         key.type = BTRFS_EXTENT_REF_KEY;
2854         key.offset = 0;
2855
2856         while(1) {
2857                 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2858
2859                 if (ret < 0)
2860                         goto out;
2861
2862                 ret = 0;
2863                 leaf = path->nodes[0];
2864                 nritems = btrfs_header_nritems(leaf);
2865                 if (path->slots[0] == nritems) {
2866                         ret = btrfs_next_leaf(extent_root, path);
2867                         if (ret > 0) {
2868                                 ret = 0;
2869                                 goto out;
2870                         }
2871                         if (ret < 0)
2872                                 goto out;
2873                         leaf = path->nodes[0];
2874                 }
2875
2876                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2877                 if (found_key.objectid != extent_key->objectid) {
2878                         break;
2879                 }
2880
2881                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
2882                         break;
2883                 }
2884
2885                 key.offset = found_key.offset + 1;
2886                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2887
2888                 ret = relocate_one_reference(extent_root, path, extent_key,
2889                                              &last_file_objectid,
2890                                              &last_file_offset,
2891                                              &last_file_root, last_extent);
2892                 if (ret)
2893                         goto out;
2894                 last_extent = extent_key->objectid;
2895         }
2896         ret = 0;
2897 out:
2898         btrfs_release_path(extent_root, path);
2899         return ret;
2900 }
2901
2902 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
2903 {
2904         u64 num_devices;
2905         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
2906                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
2907
2908         num_devices = root->fs_info->fs_devices->num_devices;
2909         if (num_devices == 1) {
2910                 stripped |= BTRFS_BLOCK_GROUP_DUP;
2911                 stripped = flags & ~stripped;
2912
2913                 /* turn raid0 into single device chunks */
2914                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
2915                         return stripped;
2916
2917                 /* turn mirroring into duplication */
2918                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2919                              BTRFS_BLOCK_GROUP_RAID10))
2920                         return stripped | BTRFS_BLOCK_GROUP_DUP;
2921                 return flags;
2922         } else {
2923                 /* they already had raid on here, just return */
2924                 if (flags & stripped)
2925                         return flags;
2926
2927                 stripped |= BTRFS_BLOCK_GROUP_DUP;
2928                 stripped = flags & ~stripped;
2929
2930                 /* switch duplicated blocks with raid1 */
2931                 if (flags & BTRFS_BLOCK_GROUP_DUP)
2932                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
2933
2934                 /* turn single device chunks into raid0 */
2935                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
2936         }
2937         return flags;
2938 }
2939
2940 int __alloc_chunk_for_shrink(struct btrfs_root *root,
2941                      struct btrfs_block_group_cache *shrink_block_group,
2942                      int force)
2943 {
2944         struct btrfs_trans_handle *trans;
2945         u64 new_alloc_flags;
2946         u64 calc;
2947
2948         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
2949
2950                 trans = btrfs_start_transaction(root, 1);
2951                 new_alloc_flags = update_block_group_flags(root,
2952                                                    shrink_block_group->flags);
2953                 if (new_alloc_flags != shrink_block_group->flags) {
2954                         calc =
2955                              btrfs_block_group_used(&shrink_block_group->item);
2956                 } else {
2957                         calc = shrink_block_group->key.offset;
2958                 }
2959                 do_chunk_alloc(trans, root->fs_info->extent_root,
2960                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
2961                 btrfs_end_transaction(trans, root);
2962         }
2963         return 0;
2964 }
2965
2966 int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 shrink_start)
2967 {
2968         struct btrfs_trans_handle *trans;
2969         struct btrfs_root *tree_root = root->fs_info->tree_root;
2970         struct btrfs_path *path;
2971         u64 cur_byte;
2972         u64 total_found;
2973         u64 shrink_last_byte;
2974         struct btrfs_block_group_cache *shrink_block_group;
2975         struct btrfs_fs_info *info = root->fs_info;
2976         struct btrfs_key key;
2977         struct btrfs_key found_key;
2978         struct extent_buffer *leaf;
2979         u32 nritems;
2980         int ret;
2981         int progress;
2982
2983         mutex_lock(&root->fs_info->alloc_mutex);
2984         shrink_block_group = btrfs_lookup_block_group(root->fs_info,
2985                                                       shrink_start);
2986         BUG_ON(!shrink_block_group);
2987
2988         shrink_last_byte = shrink_block_group->key.objectid +
2989                 shrink_block_group->key.offset;
2990
2991         shrink_block_group->space_info->total_bytes -=
2992                 shrink_block_group->key.offset;
2993         path = btrfs_alloc_path();
2994         root = root->fs_info->extent_root;
2995         path->reada = 2;
2996
2997         printk("btrfs relocating block group %llu flags %llu\n",
2998                (unsigned long long)shrink_start,
2999                (unsigned long long)shrink_block_group->flags);
3000
3001         __alloc_chunk_for_shrink(root, shrink_block_group, 1);
3002
3003 again:
3004
3005         shrink_block_group->ro = 1;
3006
3007         total_found = 0;
3008         progress = 0;
3009         key.objectid = shrink_start;
3010         key.offset = 0;
3011         key.type = 0;
3012         cur_byte = key.objectid;
3013
3014         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3015         if (ret < 0)
3016                 goto out;
3017
3018         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
3019         if (ret < 0)
3020                 goto out;
3021
3022         if (ret == 0) {
3023                 leaf = path->nodes[0];
3024                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3025                 if (found_key.objectid + found_key.offset > shrink_start &&
3026                     found_key.objectid < shrink_last_byte) {
3027                         cur_byte = found_key.objectid;
3028                         key.objectid = cur_byte;
3029                 }
3030         }
3031         btrfs_release_path(root, path);
3032
3033         while(1) {
3034                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3035                 if (ret < 0)
3036                         goto out;
3037
3038                 leaf = path->nodes[0];
3039                 nritems = btrfs_header_nritems(leaf);
3040 next:
3041                 if (path->slots[0] >= nritems) {
3042                         ret = btrfs_next_leaf(root, path);
3043                         if (ret < 0)
3044                                 goto out;
3045                         if (ret == 1) {
3046                                 ret = 0;
3047                                 break;
3048                         }
3049                         leaf = path->nodes[0];
3050                         nritems = btrfs_header_nritems(leaf);
3051                 }
3052
3053                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3054
3055                 if (found_key.objectid >= shrink_last_byte)
3056                         break;
3057
3058                 if (progress && need_resched()) {
3059                         memcpy(&key, &found_key, sizeof(key));
3060                         cond_resched();
3061                         btrfs_release_path(root, path);
3062                         btrfs_search_slot(NULL, root, &key, path, 0, 0);
3063                         progress = 0;
3064                         goto next;
3065                 }
3066                 progress = 1;
3067
3068                 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||
3069                     found_key.objectid + found_key.offset <= cur_byte) {
3070                         memcpy(&key, &found_key, sizeof(key));
3071                         key.offset++;
3072                         path->slots[0]++;
3073                         goto next;
3074                 }
3075
3076                 total_found++;
3077                 cur_byte = found_key.objectid + found_key.offset;
3078                 key.objectid = cur_byte;
3079                 btrfs_release_path(root, path);
3080                 ret = relocate_one_extent(root, path, &found_key);
3081                 __alloc_chunk_for_shrink(root, shrink_block_group, 0);
3082         }
3083
3084         btrfs_release_path(root, path);
3085
3086         if (total_found > 0) {
3087                 printk("btrfs relocate found %llu last extent was %llu\n",
3088                        (unsigned long long)total_found,
3089                        (unsigned long long)found_key.objectid);
3090                 trans = btrfs_start_transaction(tree_root, 1);
3091                 btrfs_commit_transaction(trans, tree_root);
3092
3093                 btrfs_clean_old_snapshots(tree_root);
3094
3095                 trans = btrfs_start_transaction(tree_root, 1);
3096                 btrfs_commit_transaction(trans, tree_root);
3097                 goto again;
3098         }
3099
3100         /*
3101          * we've freed all the extents, now remove the block
3102          * group item from the tree
3103          */
3104         trans = btrfs_start_transaction(root, 1);
3105         memcpy(&key, &shrink_block_group->key, sizeof(key));
3106
3107         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3108         if (ret > 0)
3109                 ret = -EIO;
3110         if (ret < 0)
3111                 goto out;
3112
3113         clear_extent_bits(&info->block_group_cache, key.objectid,
3114                           key.objectid + key.offset - 1,
3115                           (unsigned int)-1, GFP_NOFS);
3116
3117
3118         clear_extent_bits(&info->free_space_cache,
3119                            key.objectid, key.objectid + key.offset - 1,
3120                            (unsigned int)-1, GFP_NOFS);
3121
3122         memset(shrink_block_group, 0, sizeof(*shrink_block_group));
3123         kfree(shrink_block_group);
3124
3125         btrfs_del_item(trans, root, path);
3126         btrfs_commit_transaction(trans, root);
3127
3128         /* the code to unpin extents might set a few bits in the free
3129          * space cache for this range again
3130          */
3131         clear_extent_bits(&info->free_space_cache,
3132                            key.objectid, key.objectid + key.offset - 1,
3133                            (unsigned int)-1, GFP_NOFS);
3134 out:
3135         btrfs_free_path(path);
3136         mutex_unlock(&root->fs_info->alloc_mutex);
3137         return ret;
3138 }
3139
3140 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3141                            struct btrfs_key *key)
3142 {
3143         int ret = 0;
3144         struct btrfs_key found_key;
3145         struct extent_buffer *leaf;
3146         int slot;
3147
3148         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3149         if (ret < 0)
3150                 goto out;
3151
3152         while(1) {
3153                 slot = path->slots[0];
3154                 leaf = path->nodes[0];
3155                 if (slot >= btrfs_header_nritems(leaf)) {
3156                         ret = btrfs_next_leaf(root, path);
3157                         if (ret == 0)
3158                                 continue;
3159                         if (ret < 0)
3160                                 goto out;
3161                         break;
3162                 }
3163                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3164
3165                 if (found_key.objectid >= key->objectid &&
3166                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
3167                         ret = 0;
3168                         goto out;
3169                 }
3170                 path->slots[0]++;
3171         }
3172         ret = -ENOENT;
3173 out:
3174         return ret;
3175 }
3176
3177 int btrfs_read_block_groups(struct btrfs_root *root)
3178 {
3179         struct btrfs_path *path;
3180         int ret;
3181         int bit;
3182         struct btrfs_block_group_cache *cache;
3183         struct btrfs_fs_info *info = root->fs_info;
3184         struct btrfs_space_info *space_info;
3185         struct extent_io_tree *block_group_cache;
3186         struct btrfs_key key;
3187         struct btrfs_key found_key;
3188         struct extent_buffer *leaf;
3189
3190         block_group_cache = &info->block_group_cache;
3191         root = info->extent_root;
3192         key.objectid = 0;
3193         key.offset = 0;
3194         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3195         path = btrfs_alloc_path();
3196         if (!path)
3197                 return -ENOMEM;
3198
3199         mutex_lock(&root->fs_info->alloc_mutex);
3200         while(1) {
3201                 ret = find_first_block_group(root, path, &key);
3202                 if (ret > 0) {
3203                         ret = 0;
3204                         goto error;
3205                 }
3206                 if (ret != 0)
3207                         goto error;
3208
3209                 leaf = path->nodes[0];
3210                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3211                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3212                 if (!cache) {
3213                         ret = -ENOMEM;
3214                         break;
3215                 }
3216
3217                 read_extent_buffer(leaf, &cache->item,
3218                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
3219                                    sizeof(cache->item));
3220                 memcpy(&cache->key, &found_key, sizeof(found_key));
3221
3222                 key.objectid = found_key.objectid + found_key.offset;
3223                 btrfs_release_path(root, path);
3224                 cache->flags = btrfs_block_group_flags(&cache->item);
3225                 bit = 0;
3226                 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3227                         bit = BLOCK_GROUP_DATA;
3228                 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3229                         bit = BLOCK_GROUP_SYSTEM;
3230                 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3231                         bit = BLOCK_GROUP_METADATA;
3232                 }
3233                 set_avail_alloc_bits(info, cache->flags);
3234
3235                 ret = update_space_info(info, cache->flags, found_key.offset,
3236                                         btrfs_block_group_used(&cache->item),
3237                                         &space_info);
3238                 BUG_ON(ret);
3239                 cache->space_info = space_info;
3240
3241                 /* use EXTENT_LOCKED to prevent merging */
3242                 set_extent_bits(block_group_cache, found_key.objectid,
3243                                 found_key.objectid + found_key.offset - 1,
3244                                 bit | EXTENT_LOCKED, GFP_NOFS);
3245                 set_state_private(block_group_cache, found_key.objectid,
3246                                   (unsigned long)cache);
3247
3248                 if (key.objectid >=
3249                     btrfs_super_total_bytes(&info->super_copy))
3250                         break;
3251         }
3252         ret = 0;
3253 error:
3254         btrfs_free_path(path);
3255         mutex_unlock(&root->fs_info->alloc_mutex);
3256         return ret;
3257 }
3258
3259 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3260                            struct btrfs_root *root, u64 bytes_used,
3261                            u64 type, u64 chunk_objectid, u64 chunk_offset,
3262                            u64 size)
3263 {
3264         int ret;
3265         int bit = 0;
3266         struct btrfs_root *extent_root;
3267         struct btrfs_block_group_cache *cache;
3268         struct extent_io_tree *block_group_cache;
3269
3270         extent_root = root->fs_info->extent_root;
3271         block_group_cache = &root->fs_info->block_group_cache;
3272
3273         cache = kzalloc(sizeof(*cache), GFP_NOFS);
3274         BUG_ON(!cache);
3275         cache->key.objectid = chunk_offset;
3276         cache->key.offset = size;
3277         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3278
3279         btrfs_set_block_group_used(&cache->item, bytes_used);
3280         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3281         cache->flags = type;
3282         btrfs_set_block_group_flags(&cache->item, type);
3283
3284         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3285                                 &cache->space_info);
3286         BUG_ON(ret);
3287
3288         bit = block_group_state_bits(type);
3289         set_extent_bits(block_group_cache, chunk_offset,
3290                         chunk_offset + size - 1,
3291                         bit | EXTENT_LOCKED, GFP_NOFS);
3292
3293         set_state_private(block_group_cache, chunk_offset,
3294                           (unsigned long)cache);
3295         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3296                                 sizeof(cache->item));
3297         BUG_ON(ret);
3298
3299         finish_current_insert(trans, extent_root);
3300         ret = del_pending_extents(trans, extent_root);
3301         BUG_ON(ret);
3302         set_avail_alloc_bits(extent_root->fs_info, type);
3303
3304         return 0;
3305 }