Pileus Git - ~andy/linux/blob - fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include "hash.h"
  23 #include "crc32c.h"
  24 #include "ctree.h"
  25 #include "disk-io.h"
  26 #include "print-tree.h"
  27 #include "transaction.h"
  28 #include "volumes.h"
  29 #include "locking.h"
  30 #include "ref-cache.h"
  31
  32 #define PENDING_EXTENT_INSERT 0
  33 #define PENDING_EXTENT_DELETE 1
  34 #define PENDING_BACKREF_UPDATE 2
  35
  36 struct pending_extent_op {
  37         int type;
  38         u64 bytenr;
  39         u64 num_bytes;
  40         u64 parent;
  41         u64 orig_parent;
  42         u64 generation;
  43         u64 orig_generation;
  44         int level;
  45 };
  46
  47 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  48                                  btrfs_root *extent_root, int all);
  49 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  50                                btrfs_root *extent_root, int all);
  51 static struct btrfs_block_group_cache *
  52 __btrfs_find_block_group(struct btrfs_root *root,
  53                          struct btrfs_block_group_cache *hint,
  54                          u64 search_start, int data, int owner);
  55
  56 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  57 {
  58         return (cache->flags & bits) == bits;
  59 }
  60
  61 /*
  62  * this adds the block group to the fs_info rb tree for the block group
  63  * cache
  64  */
  65 int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
  66                                 struct btrfs_block_group_cache *block_group)
  67 {
  68         struct rb_node **p;
  69         struct rb_node *parent = NULL;
  70         struct btrfs_block_group_cache *cache;
  71
  72         spin_lock(&info->block_group_cache_lock);
  73         p = &info->block_group_cache_tree.rb_node;
  74
  75         while (*p) {
  76                 parent = *p;
  77                 cache = rb_entry(parent, struct btrfs_block_group_cache,
  78                                  cache_node);
  79                 if (block_group->key.objectid < cache->key.objectid) {
  80                         p = &(*p)->rb_left;
  81                 } else if (block_group->key.objectid > cache->key.objectid) {
  82                         p = &(*p)->rb_right;
  83                 } else {
  84                         spin_unlock(&info->block_group_cache_lock);
  85                         return -EEXIST;
  86                 }
  87         }
  88
  89         rb_link_node(&block_group->cache_node, parent, p);
  90         rb_insert_color(&block_group->cache_node,
  91                         &info->block_group_cache_tree);
  92         spin_unlock(&info->block_group_cache_lock);
  93
  94         return 0;
  95 }
  96
  97 /*
  98  * This will return the block group at or after bytenr if contains is 0, else
  99  * it will return the block group that contains the bytenr
 100  */
 101 static struct btrfs_block_group_cache *
 102 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 103                               int contains)
 104 {
 105         struct btrfs_block_group_cache *cache, *ret = NULL;
 106         struct rb_node *n;
 107         u64 end, start;
 108
 109         spin_lock(&info->block_group_cache_lock);
 110         n = info->block_group_cache_tree.rb_node;
 111
 112         while (n) {
 113                 cache = rb_entry(n, struct btrfs_block_group_cache,
 114                                  cache_node);
 115                 end = cache->key.objectid + cache->key.offset - 1;
 116                 start = cache->key.objectid;
 117
 118                 if (bytenr < start) {
 119                         if (!contains && (!ret || start < ret->key.objectid))
 120                                 ret = cache;
 121                         n = n->rb_left;
 122                 } else if (bytenr > start) {
 123                         if (contains && bytenr <= end) {
 124                                 ret = cache;
 125                                 break;
 126                         }
 127                         n = n->rb_right;
 128                 } else {
 129                         ret = cache;
 130                         break;
 131                 }
 132         }
 133         spin_unlock(&info->block_group_cache_lock);
 134
 135         return ret;
 136 }
 137
 138 /*
 139  * this is only called by cache_block_group, since we could have freed extents
 140  * we need to check the pinned_extents for any extents that can't be used yet
 141  * since their free space will be released as soon as the transaction commits.
 142  */
 143 static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 144                               struct btrfs_fs_info *info, u64 start, u64 end)
 145 {
 146         u64 extent_start, extent_end, size;
 147         int ret;
 148
 149         mutex_lock(&info->pinned_mutex);
 150         while (start < end) {
 151                 ret = find_first_extent_bit(&info->pinned_extents, start,
 152                                             &extent_start, &extent_end,
 153                                             EXTENT_DIRTY);
 154                 if (ret)
 155                         break;
 156
 157                 if (extent_start == start) {
 158                         start = extent_end + 1;
 159                 } else if (extent_start > start && extent_start < end) {
 160                         size = extent_start - start;
 161                         ret = btrfs_add_free_space_lock(block_group, start,
 162                                                         size);
 163                         BUG_ON(ret);
 164                         start = extent_end + 1;
 165                 } else {
 166                         break;
 167                 }
 168         }
 169
 170         if (start < end) {
 171                 size = end - start;
 172                 ret = btrfs_add_free_space_lock(block_group, start, size);
 173                 BUG_ON(ret);
 174         }
 175         mutex_unlock(&info->pinned_mutex);
 176
 177         return 0;
 178 }
 179
 180 static int cache_block_group(struct btrfs_root *root,
 181                              struct btrfs_block_group_cache *block_group)
 182 {
 183         struct btrfs_path *path;
 184         int ret = 0;
 185         struct btrfs_key key;
 186         struct extent_buffer *leaf;
 187         int slot;
 188         u64 last = 0;
 189         u64 first_free;
 190         int found = 0;
 191
 192         if (!block_group)
 193                 return 0;
 194
 195         root = root->fs_info->extent_root;
 196
 197         if (block_group->cached)
 198                 return 0;
 199
 200         path = btrfs_alloc_path();
 201         if (!path)
 202                 return -ENOMEM;
 203
 204         path->reada = 2;
 205         /*
 206          * we get into deadlocks with paths held by callers of this function.
 207          * since the alloc_mutex is protecting things right now, just
 208          * skip the locking here
 209          */
 210         path->skip_locking = 1;
 211         first_free = max_t(u64, block_group->key.objectid,
 212                            BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 213         key.objectid = block_group->key.objectid;
 214         key.offset = 0;
 215         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 216         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 217         if (ret < 0)
 218                 goto err;
 219         ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
 220         if (ret < 0)
 221                 goto err;
 222         if (ret == 0) {
 223                 leaf = path->nodes[0];
 224                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 225                 if (key.objectid + key.offset > first_free)
 226                         first_free = key.objectid + key.offset;
 227         }
 228         while(1) {
 229                 leaf = path->nodes[0];
 230                 slot = path->slots[0];
 231                 if (slot >= btrfs_header_nritems(leaf)) {
 232                         ret = btrfs_next_leaf(root, path);
 233                         if (ret < 0)
 234                                 goto err;
 235                         if (ret == 0)
 236                                 continue;
 237                         else
 238                                 break;
 239                 }
 240                 btrfs_item_key_to_cpu(leaf, &key, slot);
 241                 if (key.objectid < block_group->key.objectid)
 242                         goto next;
 243
 244                 if (key.objectid >= block_group->key.objectid +
 245                     block_group->key.offset)
 246                         break;
 247
 248                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 249                         if (!found) {
 250                                 last = first_free;
 251                                 found = 1;
 252                         }
 253
 254                         add_new_free_space(block_group, root->fs_info, last,
 255                                            key.objectid);
 256
 257                         last = key.objectid + key.offset;
 258                 }
 259 next:
 260                 path->slots[0]++;
 261         }
 262
 263         if (!found)
 264                 last = first_free;
 265
 266         add_new_free_space(block_group, root->fs_info, last,
 267                            block_group->key.objectid +
 268                            block_group->key.offset);
 269
 270         block_group->cached = 1;
 271         ret = 0;
 272 err:
 273         btrfs_free_path(path);
 274         return ret;
 275 }
 276
 277 /*
 278  * return the block group that starts at or after bytenr
 279  */
 280 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
 281                                                        btrfs_fs_info *info,
 282                                                          u64 bytenr)
 283 {
 284         struct btrfs_block_group_cache *cache;
 285
 286         cache = block_group_cache_tree_search(info, bytenr, 0);
 287
 288         return cache;
 289 }
 290
 291 /*
 292  * return the block group that contains teh given bytenr
 293  */
 294 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 295                                                          btrfs_fs_info *info,
 296                                                          u64 bytenr)
 297 {
 298         struct btrfs_block_group_cache *cache;
 299
 300         cache = block_group_cache_tree_search(info, bytenr, 1);
 301
 302         return cache;
 303 }
 304
 305 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 306                                                   u64 flags)
 307 {
 308         struct list_head *head = &info->space_info;
 309         struct list_head *cur;
 310         struct btrfs_space_info *found;
 311         list_for_each(cur, head) {
 312                 found = list_entry(cur, struct btrfs_space_info, list);
 313                 if (found->flags == flags)
 314                         return found;
 315         }
 316         return NULL;
 317 }
 318
 319 static u64 div_factor(u64 num, int factor)
 320 {
 321         if (factor == 10)
 322                 return num;
 323         num *= factor;
 324         do_div(num, 10);
 325         return num;
 326 }
 327
 328 static struct btrfs_block_group_cache *
 329 __btrfs_find_block_group(struct btrfs_root *root,
 330                          struct btrfs_block_group_cache *hint,
 331                          u64 search_start, int data, int owner)
 332 {
 333         struct btrfs_block_group_cache *cache;
 334         struct btrfs_block_group_cache *found_group = NULL;
 335         struct btrfs_fs_info *info = root->fs_info;
 336         u64 used;
 337         u64 last = 0;
 338         u64 free_check;
 339         int full_search = 0;
 340         int factor = 10;
 341         int wrapped = 0;
 342
 343         if (data & BTRFS_BLOCK_GROUP_METADATA)
 344                 factor = 9;
 345
 346         if (search_start) {
 347                 struct btrfs_block_group_cache *shint;
 348                 shint = btrfs_lookup_first_block_group(info, search_start);
 349                 if (shint && block_group_bits(shint, data) && !shint->ro) {
 350                         spin_lock(&shint->lock);
 351                         used = btrfs_block_group_used(&shint->item);
 352                         if (used + shint->pinned + shint->reserved <
 353                             div_factor(shint->key.offset, factor)) {
 354                                 spin_unlock(&shint->lock);
 355                                 return shint;
 356                         }
 357                         spin_unlock(&shint->lock);
 358                 }
 359         }
 360         if (hint && !hint->ro && block_group_bits(hint, data)) {
 361                 spin_lock(&hint->lock);
 362                 used = btrfs_block_group_used(&hint->item);
 363                 if (used + hint->pinned + hint->reserved <
 364                     div_factor(hint->key.offset, factor)) {
 365                         spin_unlock(&hint->lock);
 366                         return hint;
 367                 }
 368                 spin_unlock(&hint->lock);
 369                 last = hint->key.objectid + hint->key.offset;
 370         } else {
 371                 if (hint)
 372                         last = max(hint->key.objectid, search_start);
 373                 else
 374                         last = search_start;
 375         }
 376 again:
 377         while (1) {
 378                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 379                 if (!cache)
 380                         break;
 381
 382                 spin_lock(&cache->lock);
 383                 last = cache->key.objectid + cache->key.offset;
 384                 used = btrfs_block_group_used(&cache->item);
 385
 386                 if (!cache->ro && block_group_bits(cache, data)) {
 387                         free_check = div_factor(cache->key.offset, factor);
 388                         if (used + cache->pinned + cache->reserved <
 389                             free_check) {
 390                                 found_group = cache;
 391                                 spin_unlock(&cache->lock);
 392                                 goto found;
 393                         }
 394                 }
 395                 spin_unlock(&cache->lock);
 396                 cond_resched();
 397         }
 398         if (!wrapped) {
 399                 last = search_start;
 400                 wrapped = 1;
 401                 goto again;
 402         }
 403         if (!full_search && factor < 10) {
 404                 last = search_start;
 405                 full_search = 1;
 406                 factor = 10;
 407                 goto again;
 408         }
 409 found:
 410         return found_group;
 411 }
 412
 413 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 414                                                  struct btrfs_block_group_cache
 415                                                  *hint, u64 search_start,
 416                                                  int data, int owner)
 417 {
 418
 419         struct btrfs_block_group_cache *ret;
 420         ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
 421         return ret;
 422 }
 423
 424 /* simple helper to search for an existing extent at a given offset */
 425 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 426 {
 427         int ret;
 428         struct btrfs_key key;
 429         struct btrfs_path *path;
 430
 431         path = btrfs_alloc_path();
 432         BUG_ON(!path);
 433         key.objectid = start;
 434         key.offset = len;
 435         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 436         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 437                                 0, 0);
 438         btrfs_free_path(path);
 439         return ret;
 440 }
 441
 442 /*
 443  * Back reference rules.  Back refs have three main goals:
 444  *
 445  * 1) differentiate between all holders of references to an extent so that
 446  *    when a reference is dropped we can make sure it was a valid reference
 447  *    before freeing the extent.
 448  *
 449  * 2) Provide enough information to quickly find the holders of an extent
 450  *    if we notice a given block is corrupted or bad.
 451  *
 452  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 453  *    maintenance.  This is actually the same as #2, but with a slightly
 454  *    different use case.
 455  *
 456  * File extents can be referenced by:
 457  *
 458  * - multiple snapshots, subvolumes, or different generations in one subvol
 459  * - different files inside a single subvolume
 460  * - different offsets inside a file (bookend extents in file.c)
 461  *
 462  * The extent ref structure has fields for:
 463  *
 464  * - Objectid of the subvolume root
 465  * - Generation number of the tree holding the reference
 466  * - objectid of the file holding the reference
 467  * - number of references holding by parent node (alway 1 for tree blocks)
 468  *
 469  * Btree leaf may hold multiple references to a file extent. In most cases,
 470  * these references are from same file and the corresponding offsets inside
 471  * the file are close together.
 472  *
 473  * When a file extent is allocated the fields are filled in:
 474  *     (root_key.objectid, trans->transid, inode objectid, 1)
 475  *
 476  * When a leaf is cow'd new references are added for every file extent found
 477  * in the leaf.  It looks similar to the create case, but trans->transid will
 478  * be different when the block is cow'd.
 479  *
 480  *     (root_key.objectid, trans->transid, inode objectid,
 481  *      number of references in the leaf)
 482  *
 483  * When a file extent is removed either during snapshot deletion or
 484  * file truncation, we find the corresponding back reference and check
 485  * the following fields:
 486  *
 487  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 488  *      inode objectid)
 489  *
 490  * Btree extents can be referenced by:
 491  *
 492  * - Different subvolumes
 493  * - Different generations of the same subvolume
 494  *
 495  * When a tree block is created, back references are inserted:
 496  *
 497  * (root->root_key.objectid, trans->transid, level, 1)
 498  *
 499  * When a tree block is cow'd, new back references are added for all the
 500  * blocks it points to. If the tree block isn't in reference counted root,
 501  * the old back references are removed. These new back references are of
 502  * the form (trans->transid will have increased since creation):
 503  *
 504  * (root->root_key.objectid, trans->transid, level, 1)
 505  *
 506  * When a backref is in deleting, the following fields are checked:
 507  *
 508  * if backref was for a tree root:
 509  *     (btrfs_header_owner(itself), btrfs_header_generation(itself), level)
 510  * else
 511  *     (btrfs_header_owner(parent), btrfs_header_generation(parent), level)
 512  *
 513  * Back Reference Key composing:
 514  *
 515  * The key objectid corresponds to the first byte in the extent, the key
 516  * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
 517  * byte of parent extent. If a extent is tree root, the key offset is set
 518  * to the key objectid.
 519  */
 520
 521 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
 522                                           struct btrfs_root *root,
 523                                           struct btrfs_path *path,
 524                                           u64 bytenr, u64 parent,
 525                                           u64 ref_root, u64 ref_generation,
 526                                           u64 owner_objectid, int del)
 527 {
 528         struct btrfs_key key;
 529         struct btrfs_extent_ref *ref;
 530         struct extent_buffer *leaf;
 531         u64 ref_objectid;
 532         int ret;
 533
 534         key.objectid = bytenr;
 535         key.type = BTRFS_EXTENT_REF_KEY;
 536         key.offset = parent;
 537
 538         ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
 539         if (ret < 0)
 540                 goto out;
 541         if (ret > 0) {
 542                 ret = -ENOENT;
 543                 goto out;
 544         }
 545
 546         leaf = path->nodes[0];
 547         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 548         ref_objectid = btrfs_ref_objectid(leaf, ref);
 549         if (btrfs_ref_root(leaf, ref) != ref_root ||
 550             btrfs_ref_generation(leaf, ref) != ref_generation ||
 551             (ref_objectid != owner_objectid &&
 552              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 553                 ret = -EIO;
 554                 WARN_ON(1);
 555                 goto out;
 556         }
 557         ret = 0;
 558 out:
 559         return ret;
 560 }
 561
 562 static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
 563                                           struct btrfs_root *root,
 564                                           struct btrfs_path *path,
 565                                           u64 bytenr, u64 parent,
 566                                           u64 ref_root, u64 ref_generation,
 567                                           u64 owner_objectid)
 568 {
 569         struct btrfs_key key;
 570         struct extent_buffer *leaf;
 571         struct btrfs_extent_ref *ref;
 572         u32 num_refs;
 573         int ret;
 574
 575         key.objectid = bytenr;
 576         key.type = BTRFS_EXTENT_REF_KEY;
 577         key.offset = parent;
 578
 579         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
 580         if (ret == 0) {
 581                 leaf = path->nodes[0];
 582                 ref = btrfs_item_ptr(leaf, path->slots[0],
 583                                      struct btrfs_extent_ref);
 584                 btrfs_set_ref_root(leaf, ref, ref_root);
 585                 btrfs_set_ref_generation(leaf, ref, ref_generation);
 586                 btrfs_set_ref_objectid(leaf, ref, owner_objectid);
 587                 btrfs_set_ref_num_refs(leaf, ref, 1);
 588         } else if (ret == -EEXIST) {
 589                 u64 existing_owner;
 590                 BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
 591                 leaf = path->nodes[0];
 592                 ref = btrfs_item_ptr(leaf, path->slots[0],
 593                                      struct btrfs_extent_ref);
 594                 if (btrfs_ref_root(leaf, ref) != ref_root ||
 595                     btrfs_ref_generation(leaf, ref) != ref_generation) {
 596                         ret = -EIO;
 597                         WARN_ON(1);
 598                         goto out;
 599                 }
 600
 601                 num_refs = btrfs_ref_num_refs(leaf, ref);
 602                 BUG_ON(num_refs == 0);
 603                 btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
 604
 605                 existing_owner = btrfs_ref_objectid(leaf, ref);
 606                 if (existing_owner != owner_objectid &&
 607                     existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
 608                         btrfs_set_ref_objectid(leaf, ref,
 609                                         BTRFS_MULTIPLE_OBJECTIDS);
 610                 }
 611                 ret = 0;
 612         } else {
 613                 goto out;
 614         }
 615         btrfs_mark_buffer_dirty(path->nodes[0]);
 616 out:
 617         btrfs_release_path(root, path);
 618         return ret;
 619 }
 620
 621 static int noinline remove_extent_backref(struct btrfs_trans_handle *trans,
 622                                           struct btrfs_root *root,
 623                                           struct btrfs_path *path)
 624 {
 625         struct extent_buffer *leaf;
 626         struct btrfs_extent_ref *ref;
 627         u32 num_refs;
 628         int ret = 0;
 629
 630         leaf = path->nodes[0];
 631         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 632         num_refs = btrfs_ref_num_refs(leaf, ref);
 633         BUG_ON(num_refs == 0);
 634         num_refs -= 1;
 635         if (num_refs == 0) {
 636                 ret = btrfs_del_item(trans, root, path);
 637         } else {
 638                 btrfs_set_ref_num_refs(leaf, ref, num_refs);
 639                 btrfs_mark_buffer_dirty(leaf);
 640         }
 641         btrfs_release_path(root, path);
 642         return ret;
 643 }
 644
 645 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 646                                      struct btrfs_root *root, u64 bytenr,
 647                                      u64 orig_parent, u64 parent,
 648                                      u64 orig_root, u64 ref_root,
 649                                      u64 orig_generation, u64 ref_generation,
 650                                      u64 owner_objectid)
 651 {
 652         int ret;
 653         struct btrfs_root *extent_root = root->fs_info->extent_root;
 654         struct btrfs_path *path;
 655
 656         if (root == root->fs_info->extent_root) {
 657                 struct pending_extent_op *extent_op;
 658                 u64 num_bytes;
 659
 660                 BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
 661                 num_bytes = btrfs_level_size(root, (int)owner_objectid);
 662                 mutex_lock(&root->fs_info->extent_ins_mutex);
 663                 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
 664                                 bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
 665                         u64 priv;
 666                         ret = get_state_private(&root->fs_info->extent_ins,
 667                                                 bytenr, &priv);
 668                         BUG_ON(ret);
 669                         extent_op = (struct pending_extent_op *)
 670                                                         (unsigned long)priv;
 671                         BUG_ON(extent_op->parent != orig_parent);
 672                         BUG_ON(extent_op->generation != orig_generation);
 673
 674                         extent_op->parent = parent;
 675                         extent_op->generation = ref_generation;
 676                 } else {
 677                         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
 678                         BUG_ON(!extent_op);
 679
 680                         extent_op->type = PENDING_BACKREF_UPDATE;
 681                         extent_op->bytenr = bytenr;
 682                         extent_op->num_bytes = num_bytes;
 683                         extent_op->parent = parent;
 684                         extent_op->orig_parent = orig_parent;
 685                         extent_op->generation = ref_generation;
 686                         extent_op->orig_generation = orig_generation;
 687                         extent_op->level = (int)owner_objectid;
 688
 689                         set_extent_bits(&root->fs_info->extent_ins,
 690                                         bytenr, bytenr + num_bytes - 1,
 691                                         EXTENT_WRITEBACK, GFP_NOFS);
 692                         set_state_private(&root->fs_info->extent_ins,
 693                                           bytenr, (unsigned long)extent_op);
 694                 }
 695                 mutex_unlock(&root->fs_info->extent_ins_mutex);
 696                 return 0;
 697         }
 698
 699         path = btrfs_alloc_path();
 700         if (!path)
 701                 return -ENOMEM;
 702         ret = lookup_extent_backref(trans, extent_root, path,
 703                                     bytenr, orig_parent, orig_root,
 704                                     orig_generation, owner_objectid, 1);
 705         if (ret)
 706                 goto out;
 707         ret = remove_extent_backref(trans, extent_root, path);
 708         if (ret)
 709                 goto out;
 710         ret = insert_extent_backref(trans, extent_root, path, bytenr,
 711                                     parent, ref_root, ref_generation,
 712                                     owner_objectid);
 713         BUG_ON(ret);
 714         finish_current_insert(trans, extent_root, 0);
 715         del_pending_extents(trans, extent_root, 0);
 716 out:
 717         btrfs_free_path(path);
 718         return ret;
 719 }
 720
 721 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 722                             struct btrfs_root *root, u64 bytenr,
 723                             u64 orig_parent, u64 parent,
 724                             u64 ref_root, u64 ref_generation,
 725                             u64 owner_objectid)
 726 {
 727         int ret;
 728         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 729             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 730                 return 0;
 731         ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
 732                                         parent, ref_root, ref_root,
 733                                         ref_generation, ref_generation,
 734                                         owner_objectid);
 735         return ret;
 736 }
 737
 738 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 739                                   struct btrfs_root *root, u64 bytenr,
 740                                   u64 orig_parent, u64 parent,
 741                                   u64 orig_root, u64 ref_root,
 742                                   u64 orig_generation, u64 ref_generation,
 743                                   u64 owner_objectid)
 744 {
 745         struct btrfs_path *path;
 746         int ret;
 747         struct btrfs_key key;
 748         struct extent_buffer *l;
 749         struct btrfs_extent_item *item;
 750         u32 refs;
 751
 752         path = btrfs_alloc_path();
 753         if (!path)
 754                 return -ENOMEM;
 755
 756         path->reada = 1;
 757         key.objectid = bytenr;
 758         key.type = BTRFS_EXTENT_ITEM_KEY;
 759         key.offset = (u64)-1;
 760
 761         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 762                                 0, 1);
 763         if (ret < 0)
 764                 return ret;
 765         BUG_ON(ret == 0 || path->slots[0] == 0);
 766
 767         path->slots[0]--;
 768         l = path->nodes[0];
 769
 770         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 771         BUG_ON(key.objectid != bytenr);
 772         BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
 773
 774         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 775         refs = btrfs_extent_refs(l, item);
 776         btrfs_set_extent_refs(l, item, refs + 1);
 777         btrfs_mark_buffer_dirty(path->nodes[0]);
 778
 779         btrfs_release_path(root->fs_info->extent_root, path);
 780
 781         path->reada = 1;
 782         ret = insert_extent_backref(trans, root->fs_info->extent_root,
 783                                     path, bytenr, parent,
 784                                     ref_root, ref_generation,
 785                                     owner_objectid);
 786         BUG_ON(ret);
 787         finish_current_insert(trans, root->fs_info->extent_root, 0);
 788         del_pending_extents(trans, root->fs_info->extent_root, 0);
 789
 790         btrfs_free_path(path);
 791         return 0;
 792 }
 793
 794 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 795                          struct btrfs_root *root,
 796                          u64 bytenr, u64 num_bytes, u64 parent,
 797                          u64 ref_root, u64 ref_generation,
 798                          u64 owner_objectid)
 799 {
 800         int ret;
 801         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 802             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 803                 return 0;
 804         ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
 805                                      0, ref_root, 0, ref_generation,
 806                                      owner_objectid);
 807         return ret;
 808 }
 809
 810 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
 811                          struct btrfs_root *root)
 812 {
 813         finish_current_insert(trans, root->fs_info->extent_root, 1);
 814         del_pending_extents(trans, root->fs_info->extent_root, 1);
 815         return 0;
 816 }
 817
 818 int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
 819                             struct btrfs_root *root, u64 bytenr,
 820                             u64 num_bytes, u32 *refs)
 821 {
 822         struct btrfs_path *path;
 823         int ret;
 824         struct btrfs_key key;
 825         struct extent_buffer *l;
 826         struct btrfs_extent_item *item;
 827
 828         WARN_ON(num_bytes < root->sectorsize);
 829         path = btrfs_alloc_path();
 830         path->reada = 1;
 831         key.objectid = bytenr;
 832         key.offset = num_bytes;
 833         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 834         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 835                                 0, 0);
 836         if (ret < 0)
 837                 goto out;
 838         if (ret != 0) {
 839                 btrfs_print_leaf(root, path->nodes[0]);
 840                 printk("failed to find block number %Lu\n", bytenr);
 841                 BUG();
 842         }
 843         l = path->nodes[0];
 844         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 845         *refs = btrfs_extent_refs(l, item);
 846 out:
 847         btrfs_free_path(path);
 848         return 0;
 849 }
 850
 851 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
 852                           struct btrfs_root *root, u64 bytenr)
 853 {
 854         struct btrfs_root *extent_root = root->fs_info->extent_root;
 855         struct btrfs_path *path;
 856         struct extent_buffer *leaf;
 857         struct btrfs_extent_ref *ref_item;
 858         struct btrfs_key key;
 859         struct btrfs_key found_key;
 860         u64 ref_root;
 861         u64 last_snapshot;
 862         u32 nritems;
 863         int ret;
 864
 865         key.objectid = bytenr;
 866         key.offset = (u64)-1;
 867         key.type = BTRFS_EXTENT_ITEM_KEY;
 868
 869         path = btrfs_alloc_path();
 870         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 871         if (ret < 0)
 872                 goto out;
 873         BUG_ON(ret == 0);
 874
 875         ret = -ENOENT;
 876         if (path->slots[0] == 0)
 877                 goto out;
 878
 879         path->slots[0]--;
 880         leaf = path->nodes[0];
 881         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 882
 883         if (found_key.objectid != bytenr ||
 884             found_key.type != BTRFS_EXTENT_ITEM_KEY)
 885                 goto out;
 886
 887         last_snapshot = btrfs_root_last_snapshot(&root->root_item);
 888         while (1) {
 889                 leaf = path->nodes[0];
 890                 nritems = btrfs_header_nritems(leaf);
 891                 if (path->slots[0] >= nritems) {
 892                         ret = btrfs_next_leaf(extent_root, path);
 893                         if (ret < 0)
 894                                 goto out;
 895                         if (ret == 0)
 896                                 continue;
 897                         break;
 898                 }
 899                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 900                 if (found_key.objectid != bytenr)
 901                         break;
 902
 903                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
 904                         path->slots[0]++;
 905                         continue;
 906                 }
 907
 908                 ref_item = btrfs_item_ptr(leaf, path->slots[0],
 909                                           struct btrfs_extent_ref);
 910                 ref_root = btrfs_ref_root(leaf, ref_item);
 911                 if (ref_root != root->root_key.objectid &&
 912                     ref_root != BTRFS_TREE_LOG_OBJECTID) {
 913                         ret = 1;
 914                         goto out;
 915                 }
 916                 if (btrfs_ref_generation(leaf, ref_item) <= last_snapshot) {
 917                         ret = 1;
 918                         goto out;
 919                 }
 920
 921                 path->slots[0]++;
 922         }
 923         ret = 0;
 924 out:
 925         btrfs_free_path(path);
 926         return ret;
 927 }
 928
 929 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 930                     struct extent_buffer *buf, u32 nr_extents)
 931 {
 932         struct btrfs_key key;
 933         struct btrfs_file_extent_item *fi;
 934         u64 root_gen;
 935         u32 nritems;
 936         int i;
 937         int level;
 938         int ret = 0;
 939         int shared = 0;
 940
 941         if (!root->ref_cows)
 942                 return 0;
 943
 944         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
 945                 shared = 0;
 946                 root_gen = root->root_key.offset;
 947         } else {
 948                 shared = 1;
 949                 root_gen = trans->transid - 1;
 950         }
 951
 952         level = btrfs_header_level(buf);
 953         nritems = btrfs_header_nritems(buf);
 954
 955         if (level == 0) {
 956                 struct btrfs_leaf_ref *ref;
 957                 struct btrfs_extent_info *info;
 958
 959                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
 960                 if (!ref) {
 961                         ret = -ENOMEM;
 962                         goto out;
 963                 }
 964
 965                 ref->root_gen = root_gen;
 966                 ref->bytenr = buf->start;
 967                 ref->owner = btrfs_header_owner(buf);
 968                 ref->generation = btrfs_header_generation(buf);
 969                 ref->nritems = nr_extents;
 970                 info = ref->extents;
 971
 972                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
 973                         u64 disk_bytenr;
 974                         btrfs_item_key_to_cpu(buf, &key, i);
 975                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
 976                                 continue;
 977                         fi = btrfs_item_ptr(buf, i,
 978                                             struct btrfs_file_extent_item);
 979                         if (btrfs_file_extent_type(buf, fi) ==
 980                             BTRFS_FILE_EXTENT_INLINE)
 981                                 continue;
 982                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
 983                         if (disk_bytenr == 0)
 984                                 continue;
 985
 986                         info->bytenr = disk_bytenr;
 987                         info->num_bytes =
 988                                 btrfs_file_extent_disk_num_bytes(buf, fi);
 989                         info->objectid = key.objectid;
 990                         info->offset = key.offset;
 991                         info++;
 992                 }
 993
 994                 ret = btrfs_add_leaf_ref(root, ref, shared);
 995                 if (ret == -EEXIST && shared) {
 996                         struct btrfs_leaf_ref *old;
 997                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
 998                         BUG_ON(!old);
 999                         btrfs_remove_leaf_ref(root, old);
1000                         btrfs_free_leaf_ref(root, old);
1001                         ret = btrfs_add_leaf_ref(root, ref, shared);
1002                 }
1003                 WARN_ON(ret);
1004                 btrfs_free_leaf_ref(root, ref);
1005         }
1006 out:
1007         return ret;
1008 }
1009
1010 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1011                   struct extent_buffer *orig_buf, struct extent_buffer *buf,
1012                   u32 *nr_extents)
1013 {
1014         u64 bytenr;
1015         u64 ref_root;
1016         u64 orig_root;
1017         u64 ref_generation;
1018         u64 orig_generation;
1019         u32 nritems;
1020         u32 nr_file_extents = 0;
1021         struct btrfs_key key;
1022         struct btrfs_file_extent_item *fi;
1023         int i;
1024         int level;
1025         int ret = 0;
1026         int faili = 0;
1027         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
1028                             u64, u64, u64, u64, u64, u64, u64, u64);
1029
1030         ref_root = btrfs_header_owner(buf);
1031         ref_generation = btrfs_header_generation(buf);
1032         orig_root = btrfs_header_owner(orig_buf);
1033         orig_generation = btrfs_header_generation(orig_buf);
1034
1035         nritems = btrfs_header_nritems(buf);
1036         level = btrfs_header_level(buf);
1037
1038         if (root->ref_cows) {
1039                 process_func = __btrfs_inc_extent_ref;
1040         } else {
1041                 if (level == 0 &&
1042                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1043                         goto out;
1044                 if (level != 0 &&
1045                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1046                         goto out;
1047                 process_func = __btrfs_update_extent_ref;
1048         }
1049
1050         for (i = 0; i < nritems; i++) {
1051                 cond_resched();
1052                 if (level == 0) {
1053                         btrfs_item_key_to_cpu(buf, &key, i);
1054                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1055                                 continue;
1056                         fi = btrfs_item_ptr(buf, i,
1057                                             struct btrfs_file_extent_item);
1058                         if (btrfs_file_extent_type(buf, fi) ==
1059                             BTRFS_FILE_EXTENT_INLINE)
1060                                 continue;
1061                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1062                         if (bytenr == 0)
1063                                 continue;
1064
1065                         nr_file_extents++;
1066
1067                         ret = process_func(trans, root, bytenr,
1068                                            orig_buf->start, buf->start,
1069                                            orig_root, ref_root,
1070                                            orig_generation, ref_generation,
1071                                            key.objectid);
1072
1073                         if (ret) {
1074                                 faili = i;
1075                                 WARN_ON(1);
1076                                 goto fail;
1077                         }
1078                 } else {
1079                         bytenr = btrfs_node_blockptr(buf, i);
1080                         ret = process_func(trans, root, bytenr,
1081                                            orig_buf->start, buf->start,
1082                                            orig_root, ref_root,
1083                                            orig_generation, ref_generation,
1084                                            level - 1);
1085                         if (ret) {
1086                                 faili = i;
1087                                 WARN_ON(1);
1088                                 goto fail;
1089                         }
1090                 }
1091         }
1092 out:
1093         if (nr_extents) {
1094                 if (level == 0)
1095                         *nr_extents = nr_file_extents;
1096                 else
1097                         *nr_extents = nritems;
1098         }
1099         return 0;
1100 fail:
1101         WARN_ON(1);
1102         return ret;
1103 }
1104
1105 int btrfs_update_ref(struct btrfs_trans_handle *trans,
1106                      struct btrfs_root *root, struct extent_buffer *orig_buf,
1107                      struct extent_buffer *buf, int start_slot, int nr)
1108
1109 {
1110         u64 bytenr;
1111         u64 ref_root;
1112         u64 orig_root;
1113         u64 ref_generation;
1114         u64 orig_generation;
1115         struct btrfs_key key;
1116         struct btrfs_file_extent_item *fi;
1117         int i;
1118         int ret;
1119         int slot;
1120         int level;
1121
1122         BUG_ON(start_slot < 0);
1123         BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
1124
1125         ref_root = btrfs_header_owner(buf);
1126         ref_generation = btrfs_header_generation(buf);
1127         orig_root = btrfs_header_owner(orig_buf);
1128         orig_generation = btrfs_header_generation(orig_buf);
1129         level = btrfs_header_level(buf);
1130
1131         if (!root->ref_cows) {
1132                 if (level == 0 &&
1133                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1134                         return 0;
1135                 if (level != 0 &&
1136                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1137                         return 0;
1138         }
1139
1140         for (i = 0, slot = start_slot; i < nr; i++, slot++) {
1141                 cond_resched();
1142                 if (level == 0) {
1143                         btrfs_item_key_to_cpu(buf, &key, slot);
1144                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1145                                 continue;
1146                         fi = btrfs_item_ptr(buf, slot,
1147                                             struct btrfs_file_extent_item);
1148                         if (btrfs_file_extent_type(buf, fi) ==
1149                             BTRFS_FILE_EXTENT_INLINE)
1150                                 continue;
1151                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1152                         if (bytenr == 0)
1153                                 continue;
1154                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1155                                             orig_buf->start, buf->start,
1156                                             orig_root, ref_root,
1157                                             orig_generation, ref_generation,
1158                                             key.objectid);
1159                         if (ret)
1160                                 goto fail;
1161                 } else {
1162                         bytenr = btrfs_node_blockptr(buf, slot);
1163                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1164                                             orig_buf->start, buf->start,
1165                                             orig_root, ref_root,
1166                                             orig_generation, ref_generation,
1167                                             level - 1);
1168                         if (ret)
1169                                 goto fail;
1170                 }
1171         }
1172         return 0;
1173 fail:
1174         WARN_ON(1);
1175         return -1;
1176 }
1177
1178 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1179                                  struct btrfs_root *root,
1180                                  struct btrfs_path *path,
1181                                  struct btrfs_block_group_cache *cache)
1182 {
1183         int ret;
1184         int pending_ret;
1185         struct btrfs_root *extent_root = root->fs_info->extent_root;
1186         unsigned long bi;
1187         struct extent_buffer *leaf;
1188
1189         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1190         if (ret < 0)
1191                 goto fail;
1192         BUG_ON(ret);
1193
1194         leaf = path->nodes[0];
1195         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1196         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1197         btrfs_mark_buffer_dirty(leaf);
1198         btrfs_release_path(extent_root, path);
1199 fail:
1200         finish_current_insert(trans, extent_root, 0);
1201         pending_ret = del_pending_extents(trans, extent_root, 0);
1202         if (ret)
1203                 return ret;
1204         if (pending_ret)
1205                 return pending_ret;
1206         return 0;
1207
1208 }
1209
1210 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1211                                    struct btrfs_root *root)
1212 {
1213         struct btrfs_block_group_cache *cache, *entry;
1214         struct rb_node *n;
1215         int err = 0;
1216         int werr = 0;
1217         struct btrfs_path *path;
1218         u64 last = 0;
1219
1220         path = btrfs_alloc_path();
1221         if (!path)
1222                 return -ENOMEM;
1223
1224         while(1) {
1225                 cache = NULL;
1226                 spin_lock(&root->fs_info->block_group_cache_lock);
1227                 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1228                      n; n = rb_next(n)) {
1229                         entry = rb_entry(n, struct btrfs_block_group_cache,
1230                                          cache_node);
1231                         if (entry->dirty) {
1232                                 cache = entry;
1233                                 break;
1234                         }
1235                 }
1236                 spin_unlock(&root->fs_info->block_group_cache_lock);
1237
1238                 if (!cache)
1239                         break;
1240
1241                 cache->dirty = 0;
1242                 last += cache->key.offset;
1243
1244                 err = write_one_cache_group(trans, root,
1245                                             path, cache);
1246                 /*
1247                  * if we fail to write the cache group, we want
1248                  * to keep it marked dirty in hopes that a later
1249                  * write will work
1250                  */
1251                 if (err) {
1252                         werr = err;
1253                         continue;
1254                 }
1255         }
1256         btrfs_free_path(path);
1257         return werr;
1258 }
1259
1260 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1261                              u64 total_bytes, u64 bytes_used,
1262                              struct btrfs_space_info **space_info)
1263 {
1264         struct btrfs_space_info *found;
1265
1266         found = __find_space_info(info, flags);
1267         if (found) {
1268                 spin_lock(&found->lock);
1269                 found->total_bytes += total_bytes;
1270                 found->bytes_used += bytes_used;
1271                 found->full = 0;
1272                 spin_unlock(&found->lock);
1273                 *space_info = found;
1274                 return 0;
1275         }
1276         found = kmalloc(sizeof(*found), GFP_NOFS);
1277         if (!found)
1278                 return -ENOMEM;
1279
1280         list_add(&found->list, &info->space_info);
1281         INIT_LIST_HEAD(&found->block_groups);
1282         init_rwsem(&found->groups_sem);
1283         spin_lock_init(&found->lock);
1284         found->flags = flags;
1285         found->total_bytes = total_bytes;
1286         found->bytes_used = bytes_used;
1287         found->bytes_pinned = 0;
1288         found->bytes_reserved = 0;
1289         found->full = 0;
1290         found->force_alloc = 0;
1291         *space_info = found;
1292         return 0;
1293 }
1294
1295 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1296 {
1297         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1298                                    BTRFS_BLOCK_GROUP_RAID1 |
1299                                    BTRFS_BLOCK_GROUP_RAID10 |
1300                                    BTRFS_BLOCK_GROUP_DUP);
1301         if (extra_flags) {
1302                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1303                         fs_info->avail_data_alloc_bits |= extra_flags;
1304                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1305                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1306                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1307                         fs_info->avail_system_alloc_bits |= extra_flags;
1308         }
1309 }
1310
1311 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1312 {
1313         u64 num_devices = root->fs_info->fs_devices->num_devices;
1314
1315         if (num_devices == 1)
1316                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1317         if (num_devices < 4)
1318                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1319
1320         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1321             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1322                       BTRFS_BLOCK_GROUP_RAID10))) {
1323                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1324         }
1325
1326         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1327             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1328                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1329         }
1330
1331         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1332             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1333              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1334              (flags & BTRFS_BLOCK_GROUP_DUP)))
1335                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1336         return flags;
1337 }
1338
1339 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1340                           struct btrfs_root *extent_root, u64 alloc_bytes,
1341                           u64 flags, int force)
1342 {
1343         struct btrfs_space_info *space_info;
1344         u64 thresh;
1345         u64 start;
1346         u64 num_bytes;
1347         int ret = 0, waited = 0;
1348
1349         flags = reduce_alloc_profile(extent_root, flags);
1350
1351         space_info = __find_space_info(extent_root->fs_info, flags);
1352         if (!space_info) {
1353                 ret = update_space_info(extent_root->fs_info, flags,
1354                                         0, 0, &space_info);
1355                 BUG_ON(ret);
1356         }
1357         BUG_ON(!space_info);
1358
1359         spin_lock(&space_info->lock);
1360         if (space_info->force_alloc) {
1361                 force = 1;
1362                 space_info->force_alloc = 0;
1363         }
1364         if (space_info->full) {
1365                 spin_unlock(&space_info->lock);
1366                 goto out;
1367         }
1368
1369         thresh = div_factor(space_info->total_bytes, 6);
1370         if (!force &&
1371            (space_info->bytes_used + space_info->bytes_pinned +
1372             space_info->bytes_reserved + alloc_bytes) < thresh) {
1373                 spin_unlock(&space_info->lock);
1374                 goto out;
1375         }
1376
1377         spin_unlock(&space_info->lock);
1378
1379         ret = mutex_trylock(&extent_root->fs_info->chunk_mutex);
1380         if (!ret && !force) {
1381                 goto out;
1382         } else if (!ret) {
1383                 mutex_lock(&extent_root->fs_info->chunk_mutex);
1384                 waited = 1;
1385         }
1386
1387         if (waited) {
1388                 spin_lock(&space_info->lock);
1389                 if (space_info->full) {
1390                         spin_unlock(&space_info->lock);
1391                         goto out_unlock;
1392                 }
1393                 spin_unlock(&space_info->lock);
1394         }
1395
1396         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1397         if (ret) {
1398 printk("space info full %Lu\n", flags);
1399                 space_info->full = 1;
1400                 goto out_unlock;
1401         }
1402
1403         ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1404                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1405         BUG_ON(ret);
1406 out_unlock:
1407         mutex_unlock(&extent_root->fs_info->chunk_mutex);
1408 out:
1409         return ret;
1410 }
1411
1412 static int update_block_group(struct btrfs_trans_handle *trans,
1413                               struct btrfs_root *root,
1414                               u64 bytenr, u64 num_bytes, int alloc,
1415                               int mark_free)
1416 {
1417         struct btrfs_block_group_cache *cache;
1418         struct btrfs_fs_info *info = root->fs_info;
1419         u64 total = num_bytes;
1420         u64 old_val;
1421         u64 byte_in_group;
1422
1423         while(total) {
1424                 cache = btrfs_lookup_block_group(info, bytenr);
1425                 if (!cache) {
1426                         return -1;
1427                 }
1428                 byte_in_group = bytenr - cache->key.objectid;
1429                 WARN_ON(byte_in_group > cache->key.offset);
1430
1431                 spin_lock(&cache->space_info->lock);
1432                 spin_lock(&cache->lock);
1433                 cache->dirty = 1;
1434                 old_val = btrfs_block_group_used(&cache->item);
1435                 num_bytes = min(total, cache->key.offset - byte_in_group);
1436                 if (alloc) {
1437                         old_val += num_bytes;
1438                         cache->space_info->bytes_used += num_bytes;
1439                         btrfs_set_block_group_used(&cache->item, old_val);
1440                         spin_unlock(&cache->lock);
1441                         spin_unlock(&cache->space_info->lock);
1442                 } else {
1443                         old_val -= num_bytes;
1444                         cache->space_info->bytes_used -= num_bytes;
1445                         btrfs_set_block_group_used(&cache->item, old_val);
1446                         spin_unlock(&cache->lock);
1447                         spin_unlock(&cache->space_info->lock);
1448                         if (mark_free) {
1449                                 int ret;
1450                                 ret = btrfs_add_free_space(cache, bytenr,
1451                                                            num_bytes);
1452                                 if (ret)
1453                                         return -1;
1454                         }
1455                 }
1456                 total -= num_bytes;
1457                 bytenr += num_bytes;
1458         }
1459         return 0;
1460 }
1461
1462 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1463 {
1464         struct btrfs_block_group_cache *cache;
1465
1466         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
1467         if (!cache)
1468                 return 0;
1469
1470         return cache->key.objectid;
1471 }
1472
1473 int btrfs_update_pinned_extents(struct btrfs_root *root,
1474                                 u64 bytenr, u64 num, int pin)
1475 {
1476         u64 len;
1477         struct btrfs_block_group_cache *cache;
1478         struct btrfs_fs_info *fs_info = root->fs_info;
1479
1480         WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
1481         if (pin) {
1482                 set_extent_dirty(&fs_info->pinned_extents,
1483                                 bytenr, bytenr + num - 1, GFP_NOFS);
1484         } else {
1485                 clear_extent_dirty(&fs_info->pinned_extents,
1486                                 bytenr, bytenr + num - 1, GFP_NOFS);
1487         }
1488         while (num > 0) {
1489                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1490                 BUG_ON(!cache);
1491                 len = min(num, cache->key.offset -
1492                           (bytenr - cache->key.objectid));
1493                 if (pin) {
1494                         spin_lock(&cache->space_info->lock);
1495                         spin_lock(&cache->lock);
1496                         cache->pinned += len;
1497                         cache->space_info->bytes_pinned += len;
1498                         spin_unlock(&cache->lock);
1499                         spin_unlock(&cache->space_info->lock);
1500                         fs_info->total_pinned += len;
1501                 } else {
1502                         spin_lock(&cache->space_info->lock);
1503                         spin_lock(&cache->lock);
1504                         cache->pinned -= len;
1505                         cache->space_info->bytes_pinned -= len;
1506                         spin_unlock(&cache->lock);
1507                         spin_unlock(&cache->space_info->lock);
1508                         fs_info->total_pinned -= len;
1509                 }
1510                 bytenr += len;
1511                 num -= len;
1512         }
1513         return 0;
1514 }
1515
1516 static int update_reserved_extents(struct btrfs_root *root,
1517                                    u64 bytenr, u64 num, int reserve)
1518 {
1519         u64 len;
1520         struct btrfs_block_group_cache *cache;
1521         struct btrfs_fs_info *fs_info = root->fs_info;
1522
1523         while (num > 0) {
1524                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1525                 BUG_ON(!cache);
1526                 len = min(num, cache->key.offset -
1527                           (bytenr - cache->key.objectid));
1528
1529                 spin_lock(&cache->space_info->lock);
1530                 spin_lock(&cache->lock);
1531                 if (reserve) {
1532                         cache->reserved += len;
1533                         cache->space_info->bytes_reserved += len;
1534                 } else {
1535                         cache->reserved -= len;
1536                         cache->space_info->bytes_reserved -= len;
1537                 }
1538                 spin_unlock(&cache->lock);
1539                 spin_unlock(&cache->space_info->lock);
1540                 bytenr += len;
1541                 num -= len;
1542         }
1543         return 0;
1544 }
1545
1546 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1547 {
1548         u64 last = 0;
1549         u64 start;
1550         u64 end;
1551         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1552         int ret;
1553
1554         mutex_lock(&root->fs_info->pinned_mutex);
1555         while(1) {
1556                 ret = find_first_extent_bit(pinned_extents, last,
1557                                             &start, &end, EXTENT_DIRTY);
1558                 if (ret)
1559                         break;
1560                 set_extent_dirty(copy, start, end, GFP_NOFS);
1561                 last = end + 1;
1562         }
1563         mutex_unlock(&root->fs_info->pinned_mutex);
1564         return 0;
1565 }
1566
1567 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1568                                struct btrfs_root *root,
1569                                struct extent_io_tree *unpin)
1570 {
1571         u64 start;
1572         u64 end;
1573         int ret;
1574         struct btrfs_block_group_cache *cache;
1575
1576         mutex_lock(&root->fs_info->pinned_mutex);
1577         while(1) {
1578                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1579                                             EXTENT_DIRTY);
1580                 if (ret)
1581                         break;
1582                 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
1583                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1584                 cache = btrfs_lookup_block_group(root->fs_info, start);
1585                 if (cache->cached)
1586                         btrfs_add_free_space(cache, start, end - start + 1);
1587                 if (need_resched()) {
1588                         mutex_unlock(&root->fs_info->pinned_mutex);
1589                         cond_resched();
1590                         mutex_lock(&root->fs_info->pinned_mutex);
1591                 }
1592         }
1593         mutex_unlock(&root->fs_info->pinned_mutex);
1594         return 0;
1595 }
1596
1597 static int finish_current_insert(struct btrfs_trans_handle *trans,
1598                                  struct btrfs_root *extent_root, int all)
1599 {
1600         u64 start;
1601         u64 end;
1602         u64 priv;
1603         u64 search = 0;
1604         struct btrfs_fs_info *info = extent_root->fs_info;
1605         struct btrfs_path *path;
1606         struct btrfs_extent_ref *ref;
1607         struct pending_extent_op *extent_op;
1608         struct btrfs_key key;
1609         struct btrfs_extent_item extent_item;
1610         int ret;
1611         int err = 0;
1612
1613         btrfs_set_stack_extent_refs(&extent_item, 1);
1614         path = btrfs_alloc_path();
1615
1616         while(1) {
1617                 mutex_lock(&info->extent_ins_mutex);
1618                 ret = find_first_extent_bit(&info->extent_ins, search, &start,
1619                                             &end, EXTENT_WRITEBACK);
1620                 if (ret) {
1621                         mutex_unlock(&info->extent_ins_mutex);
1622                         if (search && all) {
1623                                 search = 0;
1624                                 continue;
1625                         }
1626                         break;
1627                 }
1628
1629                 ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
1630                 if (!ret) {
1631                         search = end + 1;
1632                         mutex_unlock(&info->extent_ins_mutex);
1633                         cond_resched();
1634                         continue;
1635                 }
1636                 BUG_ON(ret < 0);
1637
1638                 ret = get_state_private(&info->extent_ins, start, &priv);
1639                 BUG_ON(ret);
1640                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1641
1642                 mutex_unlock(&info->extent_ins_mutex);
1643
1644                 if (extent_op->type == PENDING_EXTENT_INSERT) {
1645                         key.objectid = start;
1646                         key.offset = end + 1 - start;
1647                         key.type = BTRFS_EXTENT_ITEM_KEY;
1648                         err = btrfs_insert_item(trans, extent_root, &key,
1649                                         &extent_item, sizeof(extent_item));
1650                         BUG_ON(err);
1651
1652                         mutex_lock(&info->extent_ins_mutex);
1653                         clear_extent_bits(&info->extent_ins, start, end,
1654                                           EXTENT_WRITEBACK, GFP_NOFS);
1655                         mutex_unlock(&info->extent_ins_mutex);
1656
1657                         err = insert_extent_backref(trans, extent_root, path,
1658                                                 start, extent_op->parent,
1659                                                 extent_root->root_key.objectid,
1660                                                 extent_op->generation,
1661                                                 extent_op->level);
1662                         BUG_ON(err);
1663                 } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
1664                         err = lookup_extent_backref(trans, extent_root, path,
1665                                                 start, extent_op->orig_parent,
1666                                                 extent_root->root_key.objectid,
1667                                                 extent_op->orig_generation,
1668                                                 extent_op->level, 0);
1669                         BUG_ON(err);
1670
1671                         mutex_lock(&info->extent_ins_mutex);
1672                         clear_extent_bits(&info->extent_ins, start, end,
1673                                           EXTENT_WRITEBACK, GFP_NOFS);
1674                         mutex_unlock(&info->extent_ins_mutex);
1675
1676                         key.objectid = start;
1677                         key.offset = extent_op->parent;
1678                         key.type = BTRFS_EXTENT_REF_KEY;
1679                         err = btrfs_set_item_key_safe(trans, extent_root, path,
1680                                                       &key);
1681                         BUG_ON(err);
1682                         ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1683                                              struct btrfs_extent_ref);
1684                         btrfs_set_ref_generation(path->nodes[0], ref,
1685                                                  extent_op->generation);
1686                         btrfs_mark_buffer_dirty(path->nodes[0]);
1687                         btrfs_release_path(extent_root, path);
1688                 } else {
1689                         BUG_ON(1);
1690                 }
1691                 kfree(extent_op);
1692                 unlock_extent(&info->extent_ins, start, end, GFP_NOFS);
1693                 if (all)
1694                         search = 0;
1695                 else
1696                         search = end + 1;
1697
1698                 cond_resched();
1699         }
1700         btrfs_free_path(path);
1701         return 0;
1702 }
1703
1704 static int pin_down_bytes(struct btrfs_trans_handle *trans,
1705                           struct btrfs_root *root,
1706                           u64 bytenr, u64 num_bytes, int is_data)
1707 {
1708         int err = 0;
1709         struct extent_buffer *buf;
1710
1711         if (is_data)
1712                 goto pinit;
1713
1714         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1715         if (!buf)
1716                 goto pinit;
1717
1718         /* we can reuse a block if it hasn't been written
1719          * and it is from this transaction.  We can't
1720          * reuse anything from the tree log root because
1721          * it has tiny sub-transactions.
1722          */
1723         if (btrfs_buffer_uptodate(buf, 0) &&
1724             btrfs_try_tree_lock(buf)) {
1725                 u64 header_owner = btrfs_header_owner(buf);
1726                 u64 header_transid = btrfs_header_generation(buf);
1727                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
1728                     header_owner != BTRFS_TREE_RELOC_OBJECTID &&
1729                     header_transid == trans->transid &&
1730                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
1731                         clean_tree_block(NULL, root, buf);
1732                         btrfs_tree_unlock(buf);
1733                         free_extent_buffer(buf);
1734                         return 1;
1735                 }
1736                 btrfs_tree_unlock(buf);
1737         }
1738         free_extent_buffer(buf);
1739 pinit:
1740         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
1741
1742         BUG_ON(err < 0);
1743         return 0;
1744 }
1745
1746 /*
1747  * remove an extent from the root, returns 0 on success
1748  */
1749 static int __free_extent(struct btrfs_trans_handle *trans,
1750                          struct btrfs_root *root,
1751                          u64 bytenr, u64 num_bytes, u64 parent,
1752                          u64 root_objectid, u64 ref_generation,
1753                          u64 owner_objectid, int pin, int mark_free)
1754 {
1755         struct btrfs_path *path;
1756         struct btrfs_key key;
1757         struct btrfs_fs_info *info = root->fs_info;
1758         struct btrfs_root *extent_root = info->extent_root;
1759         struct extent_buffer *leaf;
1760         int ret;
1761         int extent_slot = 0;
1762         int found_extent = 0;
1763         int num_to_del = 1;
1764         struct btrfs_extent_item *ei;
1765         u32 refs;
1766
1767         key.objectid = bytenr;
1768         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1769         key.offset = num_bytes;
1770         path = btrfs_alloc_path();
1771         if (!path)
1772                 return -ENOMEM;
1773
1774         path->reada = 1;
1775         ret = lookup_extent_backref(trans, extent_root, path,
1776                                     bytenr, parent, root_objectid,
1777                                     ref_generation, owner_objectid, 1);
1778         if (ret == 0) {
1779                 struct btrfs_key found_key;
1780                 extent_slot = path->slots[0];
1781                 while(extent_slot > 0) {
1782                         extent_slot--;
1783                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1784                                               extent_slot);
1785                         if (found_key.objectid != bytenr)
1786                                 break;
1787                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1788                             found_key.offset == num_bytes) {
1789                                 found_extent = 1;
1790                                 break;
1791                         }
1792                         if (path->slots[0] - extent_slot > 5)
1793                                 break;
1794                 }
1795                 if (!found_extent) {
1796                         ret = remove_extent_backref(trans, extent_root, path);
1797                         BUG_ON(ret);
1798                         btrfs_release_path(extent_root, path);
1799                         ret = btrfs_search_slot(trans, extent_root,
1800                                                 &key, path, -1, 1);
1801                         BUG_ON(ret);
1802                         extent_slot = path->slots[0];
1803                 }
1804         } else {
1805                 btrfs_print_leaf(extent_root, path->nodes[0]);
1806                 WARN_ON(1);
1807                 printk("Unable to find ref byte nr %Lu root %Lu "
1808                        "gen %Lu owner %Lu\n", bytenr,
1809                        root_objectid, ref_generation, owner_objectid);
1810         }
1811
1812         leaf = path->nodes[0];
1813         ei = btrfs_item_ptr(leaf, extent_slot,
1814                             struct btrfs_extent_item);
1815         refs = btrfs_extent_refs(leaf, ei);
1816         BUG_ON(refs == 0);
1817         refs -= 1;
1818         btrfs_set_extent_refs(leaf, ei, refs);
1819
1820         btrfs_mark_buffer_dirty(leaf);
1821
1822         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1823                 struct btrfs_extent_ref *ref;
1824                 ref = btrfs_item_ptr(leaf, path->slots[0],
1825                                      struct btrfs_extent_ref);
1826                 BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
1827                 /* if the back ref and the extent are next to each other
1828                  * they get deleted below in one shot
1829                  */
1830                 path->slots[0] = extent_slot;
1831                 num_to_del = 2;
1832         } else if (found_extent) {
1833                 /* otherwise delete the extent back ref */
1834                 ret = remove_extent_backref(trans, extent_root, path);
1835                 BUG_ON(ret);
1836                 /* if refs are 0, we need to setup the path for deletion */
1837                 if (refs == 0) {
1838                         btrfs_release_path(extent_root, path);
1839                         ret = btrfs_search_slot(trans, extent_root, &key, path,
1840                                                 -1, 1);
1841                         BUG_ON(ret);
1842                 }
1843         }
1844
1845         if (refs == 0) {
1846                 u64 super_used;
1847                 u64 root_used;
1848 #ifdef BIO_RW_DISCARD
1849                 u64 map_length = num_bytes;
1850                 struct btrfs_multi_bio *multi = NULL;
1851 #endif
1852
1853                 if (pin) {
1854                         mutex_lock(&root->fs_info->pinned_mutex);
1855                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
1856                                 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID);
1857                         mutex_unlock(&root->fs_info->pinned_mutex);
1858                         if (ret > 0)
1859                                 mark_free = 1;
1860                         BUG_ON(ret < 0);
1861                 }
1862
1863                 /* block accounting for super block */
1864                 spin_lock_irq(&info->delalloc_lock);
1865                 super_used = btrfs_super_bytes_used(&info->super_copy);
1866                 btrfs_set_super_bytes_used(&info->super_copy,
1867                                            super_used - num_bytes);
1868                 spin_unlock_irq(&info->delalloc_lock);
1869
1870                 /* block accounting for root item */
1871                 root_used = btrfs_root_used(&root->root_item);
1872                 btrfs_set_root_used(&root->root_item,
1873                                            root_used - num_bytes);
1874                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1875                                       num_to_del);
1876                 BUG_ON(ret);
1877                 btrfs_release_path(extent_root, path);
1878                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1879                                          mark_free);
1880                 BUG_ON(ret);
1881
1882 #ifdef BIO_RW_DISCARD
1883                 /* Tell the block device(s) that the sectors can be discarded */
1884                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1885                                       bytenr, &map_length, &multi, 0);
1886                 if (!ret) {
1887                         struct btrfs_bio_stripe *stripe = multi->stripes;
1888                         int i;
1889
1890                         if (map_length > num_bytes)
1891                                 map_length = num_bytes;
1892
1893                         for (i = 0; i < multi->num_stripes; i++, stripe++) {
1894                                 blkdev_issue_discard(stripe->dev->bdev,
1895                                                      stripe->physical >> 9,
1896                                                      map_length >> 9);
1897                         }
1898                         kfree(multi);
1899                 }
1900 #endif
1901         }
1902         btrfs_free_path(path);
1903         finish_current_insert(trans, extent_root, 0);
1904         return ret;
1905 }
1906
1907 /*
1908  * find all the blocks marked as pending in the radix tree and remove
1909  * them from the extent map
1910  */
1911 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1912                                btrfs_root *extent_root, int all)
1913 {
1914         int ret;
1915         int err = 0;
1916         u64 start;
1917         u64 end;
1918         u64 priv;
1919         u64 search = 0;
1920         struct extent_io_tree *pending_del;
1921         struct extent_io_tree *extent_ins;
1922         struct pending_extent_op *extent_op;
1923         struct btrfs_fs_info *info = extent_root->fs_info;
1924
1925         extent_ins = &extent_root->fs_info->extent_ins;
1926         pending_del = &extent_root->fs_info->pending_del;
1927
1928         while(1) {
1929                 mutex_lock(&info->extent_ins_mutex);
1930                 ret = find_first_extent_bit(pending_del, search, &start, &end,
1931                                             EXTENT_WRITEBACK);
1932                 if (ret) {
1933                         mutex_unlock(&info->extent_ins_mutex);
1934                         if (all && search) {
1935                                 search = 0;
1936                                 continue;
1937                         }
1938                         break;
1939                 }
1940
1941                 ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
1942                 if (!ret) {
1943                         search = end+1;
1944                         mutex_unlock(&info->extent_ins_mutex);
1945                         cond_resched();
1946                         continue;
1947                 }
1948                 BUG_ON(ret < 0);
1949
1950                 ret = get_state_private(pending_del, start, &priv);
1951                 BUG_ON(ret);
1952                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1953
1954                 clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
1955                                   GFP_NOFS);
1956                 if (!test_range_bit(extent_ins, start, end,
1957                                     EXTENT_WRITEBACK, 0)) {
1958                         mutex_unlock(&info->extent_ins_mutex);
1959 free_extent:
1960                         ret = __free_extent(trans, extent_root,
1961                                             start, end + 1 - start,
1962                                             extent_op->orig_parent,
1963                                             extent_root->root_key.objectid,
1964                                             extent_op->orig_generation,
1965                                             extent_op->level, 1, 0);
1966                         kfree(extent_op);
1967                 } else {
1968                         kfree(extent_op);
1969
1970                         ret = get_state_private(&info->extent_ins, start,
1971                                                 &priv);
1972                         BUG_ON(ret);
1973                         extent_op = (struct pending_extent_op *)
1974                                                 (unsigned long)priv;
1975
1976                         clear_extent_bits(&info->extent_ins, start, end,
1977                                           EXTENT_WRITEBACK, GFP_NOFS);
1978
1979                         mutex_unlock(&info->extent_ins_mutex);
1980
1981                         if (extent_op->type == PENDING_BACKREF_UPDATE)
1982                                 goto free_extent;
1983
1984                         mutex_lock(&extent_root->fs_info->pinned_mutex);
1985                         ret = pin_down_bytes(trans, extent_root, start,
1986                                              end + 1 - start, 0);
1987                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
1988
1989                         ret = update_block_group(trans, extent_root, start,
1990                                                 end + 1 - start, 0, ret > 0);
1991
1992                         BUG_ON(ret);
1993                         kfree(extent_op);
1994                 }
1995                 if (ret)
1996                         err = ret;
1997                 unlock_extent(extent_ins, start, end, GFP_NOFS);
1998
1999                 if (all)
2000                         search = 0;
2001                 else
2002                         search = end + 1;
2003                 cond_resched();
2004         }
2005         return err;
2006 }
2007
2008 /*
2009  * remove an extent from the root, returns 0 on success
2010  */
2011 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2012                                struct btrfs_root *root,
2013                                u64 bytenr, u64 num_bytes, u64 parent,
2014                                u64 root_objectid, u64 ref_generation,
2015                                u64 owner_objectid, int pin)
2016 {
2017         struct btrfs_root *extent_root = root->fs_info->extent_root;
2018         int pending_ret;
2019         int ret;
2020
2021         WARN_ON(num_bytes < root->sectorsize);
2022         if (root == extent_root) {
2023                 struct pending_extent_op *extent_op;
2024
2025                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2026                 BUG_ON(!extent_op);
2027
2028                 extent_op->type = PENDING_EXTENT_DELETE;
2029                 extent_op->bytenr = bytenr;
2030                 extent_op->num_bytes = num_bytes;
2031                 extent_op->parent = parent;
2032                 extent_op->orig_parent = parent;
2033                 extent_op->generation = ref_generation;
2034                 extent_op->orig_generation = ref_generation;
2035                 extent_op->level = (int)owner_objectid;
2036
2037                 mutex_lock(&root->fs_info->extent_ins_mutex);
2038                 set_extent_bits(&root->fs_info->pending_del,
2039                                 bytenr, bytenr + num_bytes - 1,
2040                                 EXTENT_WRITEBACK, GFP_NOFS);
2041                 set_state_private(&root->fs_info->pending_del,
2042                                   bytenr, (unsigned long)extent_op);
2043                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2044                 return 0;
2045         }
2046         /* if metadata always pin */
2047         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2048                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2049                         struct btrfs_block_group_cache *cache;
2050
2051                         /* btrfs_free_reserved_extent */
2052                         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
2053                         BUG_ON(!cache);
2054                         btrfs_add_free_space(cache, bytenr, num_bytes);
2055                         update_reserved_extents(root, bytenr, num_bytes, 0);
2056                         return 0;
2057                 }
2058                 pin = 1;
2059         }
2060
2061         /* if data pin when any transaction has committed this */
2062         if (ref_generation != trans->transid)
2063                 pin = 1;
2064
2065         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2066                             root_objectid, ref_generation,
2067                             owner_objectid, pin, pin == 0);
2068
2069         finish_current_insert(trans, root->fs_info->extent_root, 0);
2070         pending_ret = del_pending_extents(trans, root->fs_info->extent_root, 0);
2071         return ret ? ret : pending_ret;
2072 }
2073
2074 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2075                       struct btrfs_root *root,
2076                       u64 bytenr, u64 num_bytes, u64 parent,
2077                       u64 root_objectid, u64 ref_generation,
2078                       u64 owner_objectid, int pin)
2079 {
2080         int ret;
2081
2082         ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
2083                                   root_objectid, ref_generation,
2084                                   owner_objectid, pin);
2085         return ret;
2086 }
2087
2088 static u64 stripe_align(struct btrfs_root *root, u64 val)
2089 {
2090         u64 mask = ((u64)root->stripesize - 1);
2091         u64 ret = (val + mask) & ~mask;
2092         return ret;
2093 }
2094
2095 /*
2096  * walks the btree of allocated extents and find a hole of a given size.
2097  * The key ins is changed to record the hole:
2098  * ins->objectid == block start
2099  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2100  * ins->offset == number of blocks
2101  * Any available blocks before search_start are skipped.
2102  */
2103 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
2104                                      struct btrfs_root *orig_root,
2105                                      u64 num_bytes, u64 empty_size,
2106                                      u64 search_start, u64 search_end,
2107                                      u64 hint_byte, struct btrfs_key *ins,
2108                                      u64 exclude_start, u64 exclude_nr,
2109                                      int data)
2110 {
2111         int ret = 0;
2112         struct btrfs_root * root = orig_root->fs_info->extent_root;
2113         u64 total_needed = num_bytes;
2114         u64 *last_ptr = NULL;
2115         struct btrfs_block_group_cache *block_group = NULL;
2116         int chunk_alloc_done = 0;
2117         int empty_cluster = 2 * 1024 * 1024;
2118         int allowed_chunk_alloc = 0;
2119         struct list_head *head = NULL, *cur = NULL;
2120         int loop = 0;
2121         struct btrfs_space_info *space_info;
2122
2123         WARN_ON(num_bytes < root->sectorsize);
2124         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2125         ins->objectid = 0;
2126         ins->offset = 0;
2127
2128         if (orig_root->ref_cows || empty_size)
2129                 allowed_chunk_alloc = 1;
2130
2131         if (data & BTRFS_BLOCK_GROUP_METADATA) {
2132                 last_ptr = &root->fs_info->last_alloc;
2133                 empty_cluster = 256 * 1024;
2134         }
2135
2136         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
2137                 last_ptr = &root->fs_info->last_data_alloc;
2138
2139         if (last_ptr) {
2140                 if (*last_ptr)
2141                         hint_byte = *last_ptr;
2142                 else
2143                         empty_size += empty_cluster;
2144         }
2145         search_start = max(search_start, first_logical_byte(root, 0));
2146         search_start = max(search_start, hint_byte);
2147         total_needed += empty_size;
2148
2149         block_group = btrfs_lookup_block_group(root->fs_info, search_start);
2150         if (!block_group)
2151                 block_group = btrfs_lookup_first_block_group(root->fs_info,
2152                                                              search_start);
2153         space_info = __find_space_info(root->fs_info, data);
2154
2155         down_read(&space_info->groups_sem);
2156         while (1) {
2157                 struct btrfs_free_space *free_space;
2158                 /*
2159                  * the only way this happens if our hint points to a block
2160                  * group thats not of the proper type, while looping this
2161                  * should never happen
2162                  */
2163                 WARN_ON(!block_group);
2164                 mutex_lock(&block_group->alloc_mutex);
2165                 if (unlikely(!block_group_bits(block_group, data)))
2166                         goto new_group;
2167
2168                 ret = cache_block_group(root, block_group);
2169                 if (ret) {
2170                         mutex_unlock(&block_group->alloc_mutex);
2171                         break;
2172                 }
2173
2174                 if (block_group->ro)
2175                         goto new_group;
2176
2177                 free_space = btrfs_find_free_space(block_group, search_start,
2178                                                    total_needed);
2179                 if (free_space) {
2180                         u64 start = block_group->key.objectid;
2181                         u64 end = block_group->key.objectid +
2182                                 block_group->key.offset;
2183
2184                         search_start = stripe_align(root, free_space->offset);
2185
2186                         /* move on to the next group */
2187                         if (search_start + num_bytes >= search_end)
2188                                 goto new_group;
2189
2190                         /* move on to the next group */
2191                         if (search_start + num_bytes > end)
2192                                 goto new_group;
2193
2194                         if (exclude_nr > 0 &&
2195                             (search_start + num_bytes > exclude_start &&
2196                              search_start < exclude_start + exclude_nr)) {
2197                                 search_start = exclude_start + exclude_nr;
2198                                 /*
2199                                  * if search_start is still in this block group
2200                                  * then we just re-search this block group
2201                                  */
2202                                 if (search_start >= start &&
2203                                     search_start < end) {
2204                                         mutex_unlock(&block_group->alloc_mutex);
2205                                         continue;
2206                                 }
2207
2208                                 /* else we go to the next block group */
2209                                 goto new_group;
2210                         }
2211
2212                         ins->objectid = search_start;
2213                         ins->offset = num_bytes;
2214
2215                         btrfs_remove_free_space_lock(block_group, search_start,
2216                                                      num_bytes);
2217                         /* we are all good, lets return */
2218                         mutex_unlock(&block_group->alloc_mutex);
2219                         break;
2220                 }
2221 new_group:
2222                 mutex_unlock(&block_group->alloc_mutex);
2223                 /*
2224                  * Here's how this works.
2225                  * loop == 0: we were searching a block group via a hint
2226                  *              and didn't find anything, so we start at
2227                  *              the head of the block groups and keep searching
2228                  * loop == 1: we're searching through all of the block groups
2229                  *              if we hit the head again we have searched
2230                  *              all of the block groups for this space and we
2231                  *              need to try and allocate, if we cant error out.
2232                  * loop == 2: we allocated more space and are looping through
2233                  *              all of the block groups again.
2234                  */
2235                 if (loop == 0) {
2236                         head = &space_info->block_groups;
2237                         cur = head->next;
2238
2239                         if (last_ptr && *last_ptr) {
2240                                 total_needed += empty_cluster;
2241                                 *last_ptr = 0;
2242                         }
2243                         loop++;
2244                 } else if (loop == 1 && cur == head) {
2245                         if (allowed_chunk_alloc && !chunk_alloc_done) {
2246                                 up_read(&space_info->groups_sem);
2247                                 ret = do_chunk_alloc(trans, root, num_bytes +
2248                                                      2 * 1024 * 1024, data, 1);
2249                                 if (ret < 0)
2250                                         break;
2251                                 down_read(&space_info->groups_sem);
2252                                 loop++;
2253                                 head = &space_info->block_groups;
2254                                 cur = head->next;
2255                                 chunk_alloc_done = 1;
2256                         } else if (!allowed_chunk_alloc) {
2257                                 space_info->force_alloc = 1;
2258                                 break;
2259                         } else {
2260                                 break;
2261                         }
2262                 } else if (cur == head) {
2263                         break;
2264                 }
2265
2266                 block_group = list_entry(cur, struct btrfs_block_group_cache,
2267                                          list);
2268                 search_start = block_group->key.objectid;
2269                 cur = cur->next;
2270         }
2271
2272         /* we found what we needed */
2273         if (ins->objectid) {
2274                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
2275                         trans->block_group = block_group;
2276
2277                 if (last_ptr)
2278                         *last_ptr = ins->objectid + ins->offset;
2279                 ret = 0;
2280         } else if (!ret) {
2281                 ret = -ENOSPC;
2282         }
2283
2284         up_read(&space_info->groups_sem);
2285         return ret;
2286 }
2287
2288 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
2289 {
2290         struct btrfs_block_group_cache *cache;
2291         struct list_head *l;
2292
2293         printk(KERN_INFO "space_info has %Lu free, is %sfull\n",
2294                info->total_bytes - info->bytes_used - info->bytes_pinned -
2295                info->bytes_reserved, (info->full) ? "" : "not ");
2296
2297         down_read(&info->groups_sem);
2298         list_for_each(l, &info->block_groups) {
2299                 cache = list_entry(l, struct btrfs_block_group_cache, list);
2300                 spin_lock(&cache->lock);
2301                 printk(KERN_INFO "block group %Lu has %Lu bytes, %Lu used "
2302                        "%Lu pinned %Lu reserved\n",
2303                        cache->key.objectid, cache->key.offset,
2304                        btrfs_block_group_used(&cache->item),
2305                        cache->pinned, cache->reserved);
2306                 btrfs_dump_free_space(cache, bytes);
2307                 spin_unlock(&cache->lock);
2308         }
2309         up_read(&info->groups_sem);
2310 }
2311
2312 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2313                                   struct btrfs_root *root,
2314                                   u64 num_bytes, u64 min_alloc_size,
2315                                   u64 empty_size, u64 hint_byte,
2316                                   u64 search_end, struct btrfs_key *ins,
2317                                   u64 data)
2318 {
2319         int ret;
2320         u64 search_start = 0;
2321         u64 alloc_profile;
2322         struct btrfs_fs_info *info = root->fs_info;
2323
2324         if (data) {
2325                 alloc_profile = info->avail_data_alloc_bits &
2326                                 info->data_alloc_profile;
2327                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2328         } else if (root == root->fs_info->chunk_root) {
2329                 alloc_profile = info->avail_system_alloc_bits &
2330                                 info->system_alloc_profile;
2331                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2332         } else {
2333                 alloc_profile = info->avail_metadata_alloc_bits &
2334                                 info->metadata_alloc_profile;
2335                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2336         }
2337 again:
2338         data = reduce_alloc_profile(root, data);
2339         /*
2340          * the only place that sets empty_size is btrfs_realloc_node, which
2341          * is not called recursively on allocations
2342          */
2343         if (empty_size || root->ref_cows) {
2344                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2345                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2346                                      2 * 1024 * 1024,
2347                                      BTRFS_BLOCK_GROUP_METADATA |
2348                                      (info->metadata_alloc_profile &
2349                                       info->avail_metadata_alloc_bits), 0);
2350                 }
2351                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2352                                      num_bytes + 2 * 1024 * 1024, data, 0);
2353         }
2354
2355         WARN_ON(num_bytes < root->sectorsize);
2356         ret = find_free_extent(trans, root, num_bytes, empty_size,
2357                                search_start, search_end, hint_byte, ins,
2358                                trans->alloc_exclude_start,
2359                                trans->alloc_exclude_nr, data);
2360
2361         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
2362                 num_bytes = num_bytes >> 1;
2363                 num_bytes = num_bytes & ~(root->sectorsize - 1);
2364                 num_bytes = max(num_bytes, min_alloc_size);
2365                 do_chunk_alloc(trans, root->fs_info->extent_root,
2366                                num_bytes, data, 1);
2367                 goto again;
2368         }
2369         if (ret) {
2370                 struct btrfs_space_info *sinfo;
2371
2372                 sinfo = __find_space_info(root->fs_info, data);
2373                 printk("allocation failed flags %Lu, wanted %Lu\n",
2374                        data, num_bytes);
2375                 dump_space_info(sinfo, num_bytes);
2376                 BUG();
2377         }
2378
2379         return ret;
2380 }
2381
2382 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
2383 {
2384         struct btrfs_block_group_cache *cache;
2385
2386         cache = btrfs_lookup_block_group(root->fs_info, start);
2387         if (!cache) {
2388                 printk(KERN_ERR "Unable to find block group for %Lu\n", start);
2389                 return -ENOSPC;
2390         }
2391         btrfs_add_free_space(cache, start, len);
2392         update_reserved_extents(root, start, len, 0);
2393         return 0;
2394 }
2395
2396 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2397                                   struct btrfs_root *root,
2398                                   u64 num_bytes, u64 min_alloc_size,
2399                                   u64 empty_size, u64 hint_byte,
2400                                   u64 search_end, struct btrfs_key *ins,
2401                                   u64 data)
2402 {
2403         int ret;
2404         ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
2405                                      empty_size, hint_byte, search_end, ins,
2406                                      data);
2407         update_reserved_extents(root, ins->objectid, ins->offset, 1);
2408         return ret;
2409 }
2410
2411 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2412                                          struct btrfs_root *root, u64 parent,
2413                                          u64 root_objectid, u64 ref_generation,
2414                                          u64 owner, struct btrfs_key *ins)
2415 {
2416         int ret;
2417         int pending_ret;
2418         u64 super_used;
2419         u64 root_used;
2420         u64 num_bytes = ins->offset;
2421         u32 sizes[2];
2422         struct btrfs_fs_info *info = root->fs_info;
2423         struct btrfs_root *extent_root = info->extent_root;
2424         struct btrfs_extent_item *extent_item;
2425         struct btrfs_extent_ref *ref;
2426         struct btrfs_path *path;
2427         struct btrfs_key keys[2];
2428
2429         if (parent == 0)
2430                 parent = ins->objectid;
2431
2432         /* block accounting for super block */
2433         spin_lock_irq(&info->delalloc_lock);
2434         super_used = btrfs_super_bytes_used(&info->super_copy);
2435         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
2436         spin_unlock_irq(&info->delalloc_lock);
2437
2438         /* block accounting for root item */
2439         root_used = btrfs_root_used(&root->root_item);
2440         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
2441
2442         if (root == extent_root) {
2443                 struct pending_extent_op *extent_op;
2444
2445                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2446                 BUG_ON(!extent_op);
2447
2448                 extent_op->type = PENDING_EXTENT_INSERT;
2449                 extent_op->bytenr = ins->objectid;
2450                 extent_op->num_bytes = ins->offset;
2451                 extent_op->parent = parent;
2452                 extent_op->orig_parent = 0;
2453                 extent_op->generation = ref_generation;
2454                 extent_op->orig_generation = 0;
2455                 extent_op->level = (int)owner;
2456
2457                 mutex_lock(&root->fs_info->extent_ins_mutex);
2458                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2459                                 ins->objectid + ins->offset - 1,
2460                                 EXTENT_WRITEBACK, GFP_NOFS);
2461                 set_state_private(&root->fs_info->extent_ins,
2462                                   ins->objectid, (unsigned long)extent_op);
2463                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2464                 goto update_block;
2465         }
2466
2467         memcpy(&keys[0], ins, sizeof(*ins));
2468         keys[1].objectid = ins->objectid;
2469         keys[1].type = BTRFS_EXTENT_REF_KEY;
2470         keys[1].offset = parent;
2471         sizes[0] = sizeof(*extent_item);
2472         sizes[1] = sizeof(*ref);
2473
2474         path = btrfs_alloc_path();
2475         BUG_ON(!path);
2476
2477         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2478                                        sizes, 2);
2479         BUG_ON(ret);
2480
2481         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2482                                      struct btrfs_extent_item);
2483         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
2484         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2485                              struct btrfs_extent_ref);
2486
2487         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2488         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2489         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2490         btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
2491
2492         btrfs_mark_buffer_dirty(path->nodes[0]);
2493
2494         trans->alloc_exclude_start = 0;
2495         trans->alloc_exclude_nr = 0;
2496         btrfs_free_path(path);
2497         finish_current_insert(trans, extent_root, 0);
2498         pending_ret = del_pending_extents(trans, extent_root, 0);
2499
2500         if (ret)
2501                 goto out;
2502         if (pending_ret) {
2503                 ret = pending_ret;
2504                 goto out;
2505         }
2506
2507 update_block:
2508         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
2509         if (ret) {
2510                 printk("update block group failed for %Lu %Lu\n",
2511                        ins->objectid, ins->offset);
2512                 BUG();
2513         }
2514 out:
2515         return ret;
2516 }
2517
2518 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2519                                 struct btrfs_root *root, u64 parent,
2520                                 u64 root_objectid, u64 ref_generation,
2521                                 u64 owner, struct btrfs_key *ins)
2522 {
2523         int ret;
2524
2525         if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
2526                 return 0;
2527         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
2528                                             ref_generation, owner, ins);
2529         update_reserved_extents(root, ins->objectid, ins->offset, 0);
2530         return ret;
2531 }
2532
2533 /*
2534  * this is used by the tree logging recovery code.  It records that
2535  * an extent has been allocated and makes sure to clear the free
2536  * space cache bits as well
2537  */
2538 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
2539                                 struct btrfs_root *root, u64 parent,
2540                                 u64 root_objectid, u64 ref_generation,
2541                                 u64 owner, struct btrfs_key *ins)
2542 {
2543         int ret;
2544         struct btrfs_block_group_cache *block_group;
2545
2546         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
2547         mutex_lock(&block_group->alloc_mutex);
2548         cache_block_group(root, block_group);
2549
2550         ret = btrfs_remove_free_space_lock(block_group, ins->objectid,
2551                                            ins->offset);
2552         mutex_unlock(&block_group->alloc_mutex);
2553         BUG_ON(ret);
2554         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
2555                                             ref_generation, owner, ins);
2556         return ret;
2557 }
2558
2559 /*
2560  * finds a free extent and does all the dirty work required for allocation
2561  * returns the key for the extent through ins, and a tree buffer for
2562  * the first block of the extent through buf.
2563  *
2564  * returns 0 if everything worked, non-zero otherwise.
2565  */
2566 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
2567                        struct btrfs_root *root,
2568                        u64 num_bytes, u64 parent, u64 min_alloc_size,
2569                        u64 root_objectid, u64 ref_generation,
2570                        u64 owner_objectid, u64 empty_size, u64 hint_byte,
2571                        u64 search_end, struct btrfs_key *ins, u64 data)
2572 {
2573         int ret;
2574
2575         ret = __btrfs_reserve_extent(trans, root, num_bytes,
2576                                      min_alloc_size, empty_size, hint_byte,
2577                                      search_end, ins, data);
2578         BUG_ON(ret);
2579         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
2580                 ret = __btrfs_alloc_reserved_extent(trans, root, parent,
2581                                         root_objectid, ref_generation,
2582                                         owner_objectid, ins);
2583                 BUG_ON(ret);
2584
2585         } else {
2586                 update_reserved_extents(root, ins->objectid, ins->offset, 1);
2587         }
2588         return ret;
2589 }
2590
2591 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
2592                                             struct btrfs_root *root,
2593                                             u64 bytenr, u32 blocksize)
2594 {
2595         struct extent_buffer *buf;
2596
2597         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
2598         if (!buf)
2599                 return ERR_PTR(-ENOMEM);
2600         btrfs_set_header_generation(buf, trans->transid);
2601         btrfs_tree_lock(buf);
2602         clean_tree_block(trans, root, buf);
2603         btrfs_set_buffer_uptodate(buf);
2604         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2605                 set_extent_dirty(&root->dirty_log_pages, buf->start,
2606                          buf->start + buf->len - 1, GFP_NOFS);
2607         } else {
2608                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2609                          buf->start + buf->len - 1, GFP_NOFS);
2610         }
2611         trans->blocks_used++;
2612         return buf;
2613 }
2614
2615 /*
2616  * helper function to allocate a block for a given tree
2617  * returns the tree buffer or NULL.
2618  */
2619 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2620                                              struct btrfs_root *root,
2621                                              u32 blocksize, u64 parent,
2622                                              u64 root_objectid,
2623                                              u64 ref_generation,
2624                                              int level,
2625                                              u64 hint,
2626                                              u64 empty_size)
2627 {
2628         struct btrfs_key ins;
2629         int ret;
2630         struct extent_buffer *buf;
2631
2632         ret = btrfs_alloc_extent(trans, root, blocksize, parent, blocksize,
2633                                  root_objectid, ref_generation, level,
2634                                  empty_size, hint, (u64)-1, &ins, 0);
2635         if (ret) {
2636                 BUG_ON(ret > 0);
2637                 return ERR_PTR(ret);
2638         }
2639
2640         buf = btrfs_init_new_buffer(trans, root, ins.objectid, blocksize);
2641         return buf;
2642 }
2643
2644 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
2645                         struct btrfs_root *root, struct extent_buffer *leaf)
2646 {
2647         u64 leaf_owner;
2648         u64 leaf_generation;
2649         struct btrfs_key key;
2650         struct btrfs_file_extent_item *fi;
2651         int i;
2652         int nritems;
2653         int ret;
2654
2655         BUG_ON(!btrfs_is_leaf(leaf));
2656         nritems = btrfs_header_nritems(leaf);
2657         leaf_owner = btrfs_header_owner(leaf);
2658         leaf_generation = btrfs_header_generation(leaf);
2659
2660         for (i = 0; i < nritems; i++) {
2661                 u64 disk_bytenr;
2662                 cond_resched();
2663
2664                 btrfs_item_key_to_cpu(leaf, &key, i);
2665                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2666                         continue;
2667                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2668                 if (btrfs_file_extent_type(leaf, fi) ==
2669                     BTRFS_FILE_EXTENT_INLINE)
2670                         continue;
2671                 /*
2672                  * FIXME make sure to insert a trans record that
2673                  * repeats the snapshot del on crash
2674                  */
2675                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2676                 if (disk_bytenr == 0)
2677                         continue;
2678
2679                 ret = __btrfs_free_extent(trans, root, disk_bytenr,
2680                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2681                                 leaf->start, leaf_owner, leaf_generation,
2682                                 key.objectid, 0);
2683                 BUG_ON(ret);
2684
2685                 atomic_inc(&root->fs_info->throttle_gen);
2686                 wake_up(&root->fs_info->transaction_throttle);
2687                 cond_resched();
2688         }
2689         return 0;
2690 }
2691
2692 static int noinline cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
2693                                         struct btrfs_root *root,
2694                                         struct btrfs_leaf_ref *ref)
2695 {
2696         int i;
2697         int ret;
2698         struct btrfs_extent_info *info = ref->extents;
2699
2700         for (i = 0; i < ref->nritems; i++) {
2701                 ret = __btrfs_free_extent(trans, root, info->bytenr,
2702                                           info->num_bytes, ref->bytenr,
2703                                           ref->owner, ref->generation,
2704                                           info->objectid, 0);
2705
2706                 atomic_inc(&root->fs_info->throttle_gen);
2707                 wake_up(&root->fs_info->transaction_throttle);
2708                 cond_resched();
2709
2710                 BUG_ON(ret);
2711                 info++;
2712         }
2713
2714         return 0;
2715 }
2716
2717 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
2718                               u32 *refs)
2719 {
2720         int ret;
2721
2722         ret = btrfs_lookup_extent_ref(NULL, root, start, len, refs);
2723         BUG_ON(ret);
2724
2725 #if 0 // some debugging code in case we see problems here
2726         /* if the refs count is one, it won't get increased again.  But
2727          * if the ref count is > 1, someone may be decreasing it at
2728          * the same time we are.
2729          */
2730         if (*refs != 1) {
2731                 struct extent_buffer *eb = NULL;
2732                 eb = btrfs_find_create_tree_block(root, start, len);
2733                 if (eb)
2734                         btrfs_tree_lock(eb);
2735
2736                 mutex_lock(&root->fs_info->alloc_mutex);
2737                 ret = lookup_extent_ref(NULL, root, start, len, refs);
2738                 BUG_ON(ret);
2739                 mutex_unlock(&root->fs_info->alloc_mutex);
2740
2741                 if (eb) {
2742                         btrfs_tree_unlock(eb);
2743                         free_extent_buffer(eb);
2744                 }
2745                 if (*refs == 1) {
2746                         printk("block %llu went down to one during drop_snap\n",
2747                                (unsigned long long)start);
2748                 }
2749
2750         }
2751 #endif
2752
2753         cond_resched();
2754         return ret;
2755 }
2756
2757 /*
2758  * helper function for drop_snapshot, this walks down the tree dropping ref
2759  * counts as it goes.
2760  */
2761 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2762                                    struct btrfs_root *root,
2763                                    struct btrfs_path *path, int *level)
2764 {
2765         u64 root_owner;
2766         u64 root_gen;
2767         u64 bytenr;
2768         u64 ptr_gen;
2769         struct extent_buffer *next;
2770         struct extent_buffer *cur;
2771         struct extent_buffer *parent;
2772         struct btrfs_leaf_ref *ref;
2773         u32 blocksize;
2774         int ret;
2775         u32 refs;
2776
2777         WARN_ON(*level < 0);
2778         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2779         ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
2780                                 path->nodes[*level]->len, &refs);
2781         BUG_ON(ret);
2782         if (refs > 1)
2783                 goto out;
2784
2785         /*
2786          * walk down to the last node level and free all the leaves
2787          */
2788         while(*level >= 0) {
2789                 WARN_ON(*level < 0);
2790                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2791                 cur = path->nodes[*level];
2792
2793                 if (btrfs_header_level(cur) != *level)
2794                         WARN_ON(1);
2795
2796                 if (path->slots[*level] >=
2797                     btrfs_header_nritems(cur))
2798                         break;
2799                 if (*level == 0) {
2800                         ret = btrfs_drop_leaf_ref(trans, root, cur);
2801                         BUG_ON(ret);
2802                         break;
2803                 }
2804                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2805                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2806                 blocksize = btrfs_level_size(root, *level - 1);
2807
2808                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
2809                 BUG_ON(ret);
2810                 if (refs != 1) {
2811                         parent = path->nodes[*level];
2812                         root_owner = btrfs_header_owner(parent);
2813                         root_gen = btrfs_header_generation(parent);
2814                         path->slots[*level]++;
2815
2816                         ret = __btrfs_free_extent(trans, root, bytenr,
2817                                                 blocksize, parent->start,
2818                                                 root_owner, root_gen,
2819                                                 *level - 1, 1);
2820                         BUG_ON(ret);
2821
2822                         atomic_inc(&root->fs_info->throttle_gen);
2823                         wake_up(&root->fs_info->transaction_throttle);
2824                         cond_resched();
2825
2826                         continue;
2827                 }
2828                 /*
2829                  * at this point, we have a single ref, and since the
2830                  * only place referencing this extent is a dead root
2831                  * the reference count should never go higher.
2832                  * So, we don't need to check it again
2833                  */
2834                 if (*level == 1) {
2835                         ref = btrfs_lookup_leaf_ref(root, bytenr);
2836                         if (ref && ref->generation != ptr_gen) {
2837                                 btrfs_free_leaf_ref(root, ref);
2838                                 ref = NULL;
2839                         }
2840                         if (ref) {
2841                                 ret = cache_drop_leaf_ref(trans, root, ref);
2842                                 BUG_ON(ret);
2843                                 btrfs_remove_leaf_ref(root, ref);
2844                                 btrfs_free_leaf_ref(root, ref);
2845                                 *level = 0;
2846                                 break;
2847                         }
2848                         if (printk_ratelimit()) {
2849                                 printk("leaf ref miss for bytenr %llu\n",
2850                                        (unsigned long long)bytenr);
2851                         }
2852                 }
2853                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2854                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2855                         free_extent_buffer(next);
2856
2857                         next = read_tree_block(root, bytenr, blocksize,
2858                                                ptr_gen);
2859                         cond_resched();
2860 #if 0
2861                         /*
2862                          * this is a debugging check and can go away
2863                          * the ref should never go all the way down to 1
2864                          * at this point
2865                          */
2866                         ret = lookup_extent_ref(NULL, root, bytenr, blocksize,
2867                                                 &refs);
2868                         BUG_ON(ret);
2869                         WARN_ON(refs != 1);
2870 #endif
2871                 }
2872                 WARN_ON(*level <= 0);
2873                 if (path->nodes[*level-1])
2874                         free_extent_buffer(path->nodes[*level-1]);
2875                 path->nodes[*level-1] = next;
2876                 *level = btrfs_header_level(next);
2877                 path->slots[*level] = 0;
2878                 cond_resched();
2879         }
2880 out:
2881         WARN_ON(*level < 0);
2882         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2883
2884         if (path->nodes[*level] == root->node) {
2885                 parent = path->nodes[*level];
2886                 bytenr = path->nodes[*level]->start;
2887         } else {
2888                 parent = path->nodes[*level + 1];
2889                 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
2890         }
2891
2892         blocksize = btrfs_level_size(root, *level);
2893         root_owner = btrfs_header_owner(parent);
2894         root_gen = btrfs_header_generation(parent);
2895
2896         ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
2897                                   parent->start, root_owner, root_gen,
2898                                   *level, 1);
2899         free_extent_buffer(path->nodes[*level]);
2900         path->nodes[*level] = NULL;
2901         *level += 1;
2902         BUG_ON(ret);
2903
2904         cond_resched();
2905         return 0;
2906 }
2907
2908 /*
2909  * helper function for drop_subtree, this function is similar to
2910  * walk_down_tree. The main difference is that it checks reference
2911  * counts while tree blocks are locked.
2912  */
2913 static int noinline walk_down_subtree(struct btrfs_trans_handle *trans,
2914                                       struct btrfs_root *root,
2915                                       struct btrfs_path *path, int *level)
2916 {
2917         struct extent_buffer *next;
2918         struct extent_buffer *cur;
2919         struct extent_buffer *parent;
2920         u64 bytenr;
2921         u64 ptr_gen;
2922         u32 blocksize;
2923         u32 refs;
2924         int ret;
2925
2926         cur = path->nodes[*level];
2927         ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
2928                                       &refs);
2929         BUG_ON(ret);
2930         if (refs > 1)
2931                 goto out;
2932
2933         while (*level >= 0) {
2934                 cur = path->nodes[*level];
2935                 if (*level == 0) {
2936                         ret = btrfs_drop_leaf_ref(trans, root, cur);
2937                         BUG_ON(ret);
2938                         clean_tree_block(trans, root, cur);
2939                         break;
2940                 }
2941                 if (path->slots[*level] >= btrfs_header_nritems(cur)) {
2942                         clean_tree_block(trans, root, cur);
2943                         break;
2944                 }
2945
2946                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2947                 blocksize = btrfs_level_size(root, *level - 1);
2948                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2949
2950                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
2951                 btrfs_tree_lock(next);
2952
2953                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
2954                                               &refs);
2955                 BUG_ON(ret);
2956                 if (refs > 1) {
2957                         parent = path->nodes[*level];
2958                         ret = btrfs_free_extent(trans, root, bytenr,
2959                                         blocksize, parent->start,
2960                                         btrfs_header_owner(parent),
2961                                         btrfs_header_generation(parent),
2962                                         *level - 1, 1);
2963                         BUG_ON(ret);
2964                         path->slots[*level]++;
2965                         btrfs_tree_unlock(next);
2966                         free_extent_buffer(next);
2967                         continue;
2968                 }
2969
2970                 *level = btrfs_header_level(next);
2971                 path->nodes[*level] = next;
2972                 path->slots[*level] = 0;
2973                 path->locks[*level] = 1;
2974                 cond_resched();
2975         }
2976 out:
2977         parent = path->nodes[*level + 1];
2978         bytenr = path->nodes[*level]->start;
2979         blocksize = path->nodes[*level]->len;
2980
2981         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
2982                         parent->start, btrfs_header_owner(parent),
2983                         btrfs_header_generation(parent), *level, 1);
2984         BUG_ON(ret);
2985
2986         if (path->locks[*level]) {
2987                 btrfs_tree_unlock(path->nodes[*level]);
2988                 path->locks[*level] = 0;
2989         }
2990         free_extent_buffer(path->nodes[*level]);
2991         path->nodes[*level] = NULL;
2992         *level += 1;
2993         cond_resched();
2994         return 0;
2995 }
2996
2997 /*
2998  * helper for dropping snapshots.  This walks back up the tree in the path
2999  * to find the first node higher up where we haven't yet gone through
3000  * all the slots
3001  */
3002 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
3003                                  struct btrfs_root *root,
3004                                  struct btrfs_path *path,
3005                                  int *level, int max_level)
3006 {
3007         u64 root_owner;
3008         u64 root_gen;
3009         struct btrfs_root_item *root_item = &root->root_item;
3010         int i;
3011         int slot;
3012         int ret;
3013
3014         for (i = *level; i < max_level && path->nodes[i]; i++) {
3015                 slot = path->slots[i];
3016                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
3017                         struct extent_buffer *node;
3018                         struct btrfs_disk_key disk_key;
3019                         node = path->nodes[i];
3020                         path->slots[i]++;
3021                         *level = i;
3022                         WARN_ON(*level == 0);
3023                         btrfs_node_key(node, &disk_key, path->slots[i]);
3024                         memcpy(&root_item->drop_progress,
3025                                &disk_key, sizeof(disk_key));
3026                         root_item->drop_level = i;
3027                         return 0;
3028                 } else {
3029                         struct extent_buffer *parent;
3030                         if (path->nodes[*level] == root->node)
3031                                 parent = path->nodes[*level];
3032                         else
3033                                 parent = path->nodes[*level + 1];
3034
3035                         root_owner = btrfs_header_owner(parent);
3036                         root_gen = btrfs_header_generation(parent);
3037
3038                         clean_tree_block(trans, root, path->nodes[*level]);
3039                         ret = btrfs_free_extent(trans, root,
3040                                                 path->nodes[*level]->start,
3041                                                 path->nodes[*level]->len,
3042                                                 parent->start, root_owner,
3043                                                 root_gen, *level, 1);
3044                         BUG_ON(ret);
3045                         if (path->locks[*level]) {
3046                                 btrfs_tree_unlock(path->nodes[*level]);
3047                                 path->locks[*level] = 0;
3048                         }
3049                         free_extent_buffer(path->nodes[*level]);
3050                         path->nodes[*level] = NULL;
3051                         *level = i + 1;
3052                 }
3053         }
3054         return 1;
3055 }
3056
3057 /*
3058  * drop the reference count on the tree rooted at 'snap'.  This traverses
3059  * the tree freeing any blocks that have a ref count of zero after being
3060  * decremented.
3061  */
3062 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
3063                         *root)
3064 {
3065         int ret = 0;
3066         int wret;
3067         int level;
3068         struct btrfs_path *path;
3069         int i;
3070         int orig_level;
3071         struct btrfs_root_item *root_item = &root->root_item;
3072
3073         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
3074         path = btrfs_alloc_path();
3075         BUG_ON(!path);
3076
3077         level = btrfs_header_level(root->node);
3078         orig_level = level;
3079         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
3080                 path->nodes[level] = root->node;
3081                 extent_buffer_get(root->node);
3082                 path->slots[level] = 0;
3083         } else {
3084                 struct btrfs_key key;
3085                 struct btrfs_disk_key found_key;
3086                 struct extent_buffer *node;
3087
3088                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
3089                 level = root_item->drop_level;
3090                 path->lowest_level = level;
3091                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3092                 if (wret < 0) {
3093                         ret = wret;
3094                         goto out;
3095                 }
3096                 node = path->nodes[level];
3097                 btrfs_node_key(node, &found_key, path->slots[level]);
3098                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
3099                                sizeof(found_key)));
3100                 /*
3101                  * unlock our path, this is safe because only this
3102                  * function is allowed to delete this snapshot
3103                  */
3104                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3105                         if (path->nodes[i] && path->locks[i]) {
3106                                 path->locks[i] = 0;
3107                                 btrfs_tree_unlock(path->nodes[i]);
3108                         }
3109                 }
3110         }
3111         while(1) {
3112                 wret = walk_down_tree(trans, root, path, &level);
3113                 if (wret > 0)
3114                         break;
3115                 if (wret < 0)
3116                         ret = wret;
3117
3118                 wret = walk_up_tree(trans, root, path, &level,
3119                                     BTRFS_MAX_LEVEL);
3120                 if (wret > 0)
3121                         break;
3122                 if (wret < 0)
3123                         ret = wret;
3124                 if (trans->transaction->in_commit) {
3125                         ret = -EAGAIN;
3126                         break;
3127                 }
3128                 atomic_inc(&root->fs_info->throttle_gen);
3129                 wake_up(&root->fs_info->transaction_throttle);
3130         }
3131         for (i = 0; i <= orig_level; i++) {
3132                 if (path->nodes[i]) {
3133                         free_extent_buffer(path->nodes[i]);
3134                         path->nodes[i] = NULL;
3135                 }
3136         }
3137 out:
3138         btrfs_free_path(path);
3139         return ret;
3140 }
3141
3142 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
3143                         struct btrfs_root *root,
3144                         struct extent_buffer *node,
3145                         struct extent_buffer *parent)
3146 {
3147         struct btrfs_path *path;
3148         int level;
3149         int parent_level;
3150         int ret = 0;
3151         int wret;
3152
3153         path = btrfs_alloc_path();
3154         BUG_ON(!path);
3155
3156         BUG_ON(!btrfs_tree_locked(parent));
3157         parent_level = btrfs_header_level(parent);
3158         extent_buffer_get(parent);
3159         path->nodes[parent_level] = parent;
3160         path->slots[parent_level] = btrfs_header_nritems(parent);
3161
3162         BUG_ON(!btrfs_tree_locked(node));
3163         level = btrfs_header_level(node);
3164         extent_buffer_get(node);
3165         path->nodes[level] = node;
3166         path->slots[level] = 0;
3167
3168         while (1) {
3169                 wret = walk_down_subtree(trans, root, path, &level);
3170                 if (wret < 0)
3171                         ret = wret;
3172                 if (wret != 0)
3173                         break;
3174
3175                 wret = walk_up_tree(trans, root, path, &level, parent_level);
3176                 if (wret < 0)
3177                         ret = wret;
3178                 if (wret != 0)
3179                         break;
3180         }
3181
3182         btrfs_free_path(path);
3183         return ret;
3184 }
3185
3186 static unsigned long calc_ra(unsigned long start, unsigned long last,
3187                              unsigned long nr)
3188 {
3189         return min(last, start + nr - 1);
3190 }
3191
3192 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
3193                                          u64 len)
3194 {
3195         u64 page_start;
3196         u64 page_end;
3197         unsigned long first_index;
3198         unsigned long last_index;
3199         unsigned long i;
3200         struct page *page;
3201         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3202         struct file_ra_state *ra;
3203         struct btrfs_ordered_extent *ordered;
3204         unsigned int total_read = 0;
3205         unsigned int total_dirty = 0;
3206         int ret = 0;
3207
3208         ra = kzalloc(sizeof(*ra), GFP_NOFS);
3209
3210         mutex_lock(&inode->i_mutex);
3211         first_index = start >> PAGE_CACHE_SHIFT;
3212         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
3213
3214         /* make sure the dirty trick played by the caller work */
3215         ret = invalidate_inode_pages2_range(inode->i_mapping,
3216                                             first_index, last_index);
3217         if (ret)
3218                 goto out_unlock;
3219
3220         file_ra_state_init(ra, inode->i_mapping);
3221
3222         for (i = first_index ; i <= last_index; i++) {
3223                 if (total_read % ra->ra_pages == 0) {
3224                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
3225                                        calc_ra(i, last_index, ra->ra_pages));
3226                 }
3227                 total_read++;
3228 again:
3229                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
3230                         BUG_ON(1);
3231                 page = grab_cache_page(inode->i_mapping, i);
3232                 if (!page) {
3233                         ret = -ENOMEM;
3234                         goto out_unlock;
3235                 }
3236                 if (!PageUptodate(page)) {
3237                         btrfs_readpage(NULL, page);
3238                         lock_page(page);
3239                         if (!PageUptodate(page)) {
3240                                 unlock_page(page);
3241                                 page_cache_release(page);
3242                                 ret = -EIO;
3243                                 goto out_unlock;
3244                         }
3245                 }
3246                 wait_on_page_writeback(page);
3247
3248                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
3249                 page_end = page_start + PAGE_CACHE_SIZE - 1;
3250                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3251
3252                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
3253                 if (ordered) {
3254                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3255                         unlock_page(page);
3256                         page_cache_release(page);
3257                         btrfs_start_ordered_extent(inode, ordered, 1);
3258                         btrfs_put_ordered_extent(ordered);
3259                         goto again;
3260                 }
3261                 set_page_extent_mapped(page);
3262
3263                 btrfs_set_extent_delalloc(inode, page_start, page_end);
3264                 if (i == first_index)
3265                         set_extent_bits(io_tree, page_start, page_end,
3266                                         EXTENT_BOUNDARY, GFP_NOFS);
3267
3268                 set_page_dirty(page);
3269                 total_dirty++;
3270
3271                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3272                 unlock_page(page);
3273                 page_cache_release(page);
3274         }
3275
3276 out_unlock:
3277         kfree(ra);
3278         mutex_unlock(&inode->i_mutex);
3279         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
3280         return ret;
3281 }
3282
3283 static int noinline relocate_data_extent(struct inode *reloc_inode,
3284                                          struct btrfs_key *extent_key,
3285                                          u64 offset)
3286 {
3287         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
3288         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
3289         struct extent_map *em;
3290         u64 start = extent_key->objectid - offset;
3291         u64 end = start + extent_key->offset - 1;
3292
3293         em = alloc_extent_map(GFP_NOFS);
3294         BUG_ON(!em || IS_ERR(em));
3295
3296         em->start = start;
3297         em->len = extent_key->offset;
3298         em->block_len = extent_key->offset;
3299         em->block_start = extent_key->objectid;
3300         em->bdev = root->fs_info->fs_devices->latest_bdev;
3301         set_bit(EXTENT_FLAG_PINNED, &em->flags);
3302
3303         /* setup extent map to cheat btrfs_readpage */
3304         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
3305         while (1) {
3306                 int ret;
3307                 spin_lock(&em_tree->lock);
3308                 ret = add_extent_mapping(em_tree, em);
3309                 spin_unlock(&em_tree->lock);
3310                 if (ret != -EEXIST) {
3311                         free_extent_map(em);
3312                         break;
3313                 }
3314                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
3315         }
3316         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
3317
3318         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
3319 }
3320
3321 struct btrfs_ref_path {
3322         u64 extent_start;
3323         u64 nodes[BTRFS_MAX_LEVEL];
3324         u64 root_objectid;
3325         u64 root_generation;
3326         u64 owner_objectid;
3327         u32 num_refs;
3328         int lowest_level;
3329         int current_level;
3330         int shared_level;
3331
3332         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
3333         u64 new_nodes[BTRFS_MAX_LEVEL];
3334 };
3335
3336 struct disk_extent {
3337         u64 ram_bytes;
3338         u64 disk_bytenr;
3339         u64 disk_num_bytes;
3340         u64 offset;
3341         u64 num_bytes;
3342         u8 compression;
3343         u8 encryption;
3344         u16 other_encoding;
3345 };
3346
3347 static int is_cowonly_root(u64 root_objectid)
3348 {
3349         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
3350             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
3351             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
3352             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
3353             root_objectid == BTRFS_TREE_LOG_OBJECTID)
3354                 return 1;
3355         return 0;
3356 }
3357
3358 static int noinline __next_ref_path(struct btrfs_trans_handle *trans,
3359                                     struct btrfs_root *extent_root,
3360                                     struct btrfs_ref_path *ref_path,
3361                                     int first_time)
3362 {
3363         struct extent_buffer *leaf;
3364         struct btrfs_path *path;
3365         struct btrfs_extent_ref *ref;
3366         struct btrfs_key key;
3367         struct btrfs_key found_key;
3368         u64 bytenr;
3369         u32 nritems;
3370         int level;
3371         int ret = 1;
3372
3373         path = btrfs_alloc_path();
3374         if (!path)
3375                 return -ENOMEM;
3376
3377         if (first_time) {
3378                 ref_path->lowest_level = -1;
3379                 ref_path->current_level = -1;
3380                 ref_path->shared_level = -1;
3381                 goto walk_up;
3382         }
3383 walk_down:
3384         level = ref_path->current_level - 1;
3385         while (level >= -1) {
3386                 u64 parent;
3387                 if (level < ref_path->lowest_level)
3388                         break;
3389
3390                 if (level >= 0) {
3391                         bytenr = ref_path->nodes[level];
3392                 } else {
3393                         bytenr = ref_path->extent_start;
3394                 }
3395                 BUG_ON(bytenr == 0);
3396
3397                 parent = ref_path->nodes[level + 1];
3398                 ref_path->nodes[level + 1] = 0;
3399                 ref_path->current_level = level;
3400                 BUG_ON(parent == 0);
3401
3402                 key.objectid = bytenr;
3403                 key.offset = parent + 1;
3404                 key.type = BTRFS_EXTENT_REF_KEY;
3405
3406                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
3407                 if (ret < 0)
3408                         goto out;
3409                 BUG_ON(ret == 0);
3410
3411                 leaf = path->nodes[0];
3412                 nritems = btrfs_header_nritems(leaf);
3413                 if (path->slots[0] >= nritems) {
3414                         ret = btrfs_next_leaf(extent_root, path);
3415                         if (ret < 0)
3416                                 goto out;
3417                         if (ret > 0)
3418                                 goto next;
3419                         leaf = path->nodes[0];
3420                 }
3421
3422                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3423                 if (found_key.objectid == bytenr &&
3424                     found_key.type == BTRFS_EXTENT_REF_KEY) {
3425                         if (level < ref_path->shared_level)
3426                                 ref_path->shared_level = level;
3427                         goto found;
3428                 }
3429 next:
3430                 level--;
3431                 btrfs_release_path(extent_root, path);
3432                 cond_resched();
3433         }
3434         /* reached lowest level */
3435         ret = 1;
3436         goto out;
3437 walk_up:
3438         level = ref_path->current_level;
3439         while (level < BTRFS_MAX_LEVEL - 1) {
3440                 u64 ref_objectid;
3441                 if (level >= 0) {
3442                         bytenr = ref_path->nodes[level];
3443                 } else {
3444                         bytenr = ref_path->extent_start;
3445                 }
3446                 BUG_ON(bytenr == 0);
3447
3448                 key.objectid = bytenr;
3449                 key.offset = 0;
3450                 key.type = BTRFS_EXTENT_REF_KEY;
3451
3452                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
3453                 if (ret < 0)
3454                         goto out;
3455
3456                 leaf = path->nodes[0];
3457                 nritems = btrfs_header_nritems(leaf);
3458                 if (path->slots[0] >= nritems) {
3459                         ret = btrfs_next_leaf(extent_root, path);
3460                         if (ret < 0)
3461                                 goto out;
3462                         if (ret > 0) {
3463                                 /* the extent was freed by someone */
3464                                 if (ref_path->lowest_level == level)
3465                                         goto out;
3466                                 btrfs_release_path(extent_root, path);
3467                                 goto walk_down;
3468                         }
3469                         leaf = path->nodes[0];
3470                 }
3471
3472                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3473                 if (found_key.objectid != bytenr ||
3474                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
3475                         /* the extent was freed by someone */
3476                         if (ref_path->lowest_level == level) {
3477                                 ret = 1;
3478                                 goto out;
3479                         }
3480                         btrfs_release_path(extent_root, path);
3481                         goto walk_down;
3482                 }
3483 found:
3484                 ref = btrfs_item_ptr(leaf, path->slots[0],
3485                                 struct btrfs_extent_ref);
3486                 ref_objectid = btrfs_ref_objectid(leaf, ref);
3487                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
3488                         if (first_time) {
3489                                 level = (int)ref_objectid;
3490                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
3491                                 ref_path->lowest_level = level;
3492                                 ref_path->current_level = level;
3493                                 ref_path->nodes[level] = bytenr;
3494                         } else {
3495                                 WARN_ON(ref_objectid != level);
3496                         }
3497                 } else {
3498                         WARN_ON(level != -1);
3499                 }
3500                 first_time = 0;
3501
3502                 if (ref_path->lowest_level == level) {
3503                         ref_path->owner_objectid = ref_objectid;
3504                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
3505                 }
3506
3507                 /*
3508                  * the block is tree root or the block isn't in reference
3509                  * counted tree.
3510                  */
3511                 if (found_key.objectid == found_key.offset ||
3512                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
3513                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
3514                         ref_path->root_generation =
3515                                 btrfs_ref_generation(leaf, ref);
3516                         if (level < 0) {
3517                                 /* special reference from the tree log */
3518                                 ref_path->nodes[0] = found_key.offset;
3519                                 ref_path->current_level = 0;
3520                         }
3521                         ret = 0;
3522                         goto out;
3523                 }
3524
3525                 level++;
3526                 BUG_ON(ref_path->nodes[level] != 0);
3527                 ref_path->nodes[level] = found_key.offset;
3528                 ref_path->current_level = level;
3529
3530                 /*
3531                  * the reference was created in the running transaction,
3532                  * no need to continue walking up.
3533                  */
3534                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
3535                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
3536                         ref_path->root_generation =
3537                                 btrfs_ref_generation(leaf, ref);
3538                         ret = 0;
3539                         goto out;
3540                 }
3541
3542                 btrfs_release_path(extent_root, path);
3543                 cond_resched();
3544         }
3545         /* reached max tree level, but no tree root found. */
3546         BUG();
3547 out:
3548         btrfs_free_path(path);
3549         return ret;
3550 }
3551
3552 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
3553                                 struct btrfs_root *extent_root,
3554                                 struct btrfs_ref_path *ref_path,
3555                                 u64 extent_start)
3556 {
3557         memset(ref_path, 0, sizeof(*ref_path));
3558         ref_path->extent_start = extent_start;
3559
3560         return __next_ref_path(trans, extent_root, ref_path, 1);
3561 }
3562
3563 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
3564                                struct btrfs_root *extent_root,
3565                                struct btrfs_ref_path *ref_path)
3566 {
3567         return __next_ref_path(trans, extent_root, ref_path, 0);
3568 }
3569
3570 static int noinline get_new_locations(struct inode *reloc_inode,
3571                                       struct btrfs_key *extent_key,
3572                                       u64 offset, int no_fragment,
3573                                       struct disk_extent **extents,
3574                                       int *nr_extents)
3575 {
3576         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
3577         struct btrfs_path *path;
3578         struct btrfs_file_extent_item *fi;
3579         struct extent_buffer *leaf;
3580         struct disk_extent *exts = *extents;
3581         struct btrfs_key found_key;
3582         u64 cur_pos;
3583         u64 last_byte;
3584         u32 nritems;
3585         int nr = 0;
3586         int max = *nr_extents;
3587         int ret;
3588
3589         WARN_ON(!no_fragment && *extents);
3590         if (!exts) {
3591                 max = 1;
3592                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
3593                 if (!exts)
3594                         return -ENOMEM;
3595         }
3596
3597         path = btrfs_alloc_path();
3598         BUG_ON(!path);
3599
3600         cur_pos = extent_key->objectid - offset;
3601         last_byte = extent_key->objectid + extent_key->offset;
3602         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
3603                                        cur_pos, 0);
3604         if (ret < 0)
3605                 goto out;
3606         if (ret > 0) {
3607                 ret = -ENOENT;
3608                 goto out;
3609         }
3610
3611         while (1) {
3612                 leaf = path->nodes[0];
3613                 nritems = btrfs_header_nritems(leaf);
3614                 if (path->slots[0] >= nritems) {
3615                         ret = btrfs_next_leaf(root, path);
3616                         if (ret < 0)
3617                                 goto out;
3618                         if (ret > 0)
3619                                 break;
3620                         leaf = path->nodes[0];
3621                 }
3622
3623                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3624                 if (found_key.offset != cur_pos ||
3625                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
3626                     found_key.objectid != reloc_inode->i_ino)
3627                         break;
3628
3629                 fi = btrfs_item_ptr(leaf, path->slots[0],
3630                                     struct btrfs_file_extent_item);
3631                 if (btrfs_file_extent_type(leaf, fi) !=
3632                     BTRFS_FILE_EXTENT_REG ||
3633                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
3634                         break;
3635
3636                 if (nr == max) {
3637                         struct disk_extent *old = exts;
3638                         max *= 2;
3639                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
3640                         memcpy(exts, old, sizeof(*exts) * nr);
3641                         if (old != *extents)
3642                                 kfree(old);
3643                 }
3644
3645                 exts[nr].disk_bytenr =
3646                         btrfs_file_extent_disk_bytenr(leaf, fi);
3647                 exts[nr].disk_num_bytes =
3648                         btrfs_file_extent_disk_num_bytes(leaf, fi);
3649                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
3650                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
3651                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
3652                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
3653                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
3654                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
3655                                                                            fi);
3656                 BUG_ON(exts[nr].offset > 0);
3657                 BUG_ON(exts[nr].compression || exts[nr].encryption);
3658                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
3659
3660                 cur_pos += exts[nr].num_bytes;
3661                 nr++;
3662
3663                 if (cur_pos + offset >= last_byte)
3664                         break;
3665
3666                 if (no_fragment) {
3667                         ret = 1;
3668                         goto out;
3669                 }
3670                 path->slots[0]++;
3671         }
3672
3673         WARN_ON(cur_pos + offset > last_byte);
3674         if (cur_pos + offset < last_byte) {
3675                 ret = -ENOENT;
3676                 goto out;
3677         }
3678         ret = 0;
3679 out:
3680         btrfs_free_path(path);
3681         if (ret) {
3682                 if (exts != *extents)
3683                         kfree(exts);
3684         } else {
3685                 *extents = exts;
3686                 *nr_extents = nr;
3687         }
3688         return ret;
3689 }
3690
3691 static int noinline replace_one_extent(struct btrfs_trans_handle *trans,
3692                                         struct btrfs_root *root,
3693                                         struct btrfs_path *path,
3694                                         struct btrfs_key *extent_key,
3695                                         struct btrfs_key *leaf_key,
3696                                         struct btrfs_ref_path *ref_path,
3697                                         struct disk_extent *new_extents,
3698                                         int nr_extents)
3699 {
3700         struct extent_buffer *leaf;
3701         struct btrfs_file_extent_item *fi;
3702         struct inode *inode = NULL;
3703         struct btrfs_key key;
3704         u64 lock_start = 0;
3705         u64 lock_end = 0;
3706         u64 num_bytes;
3707         u64 ext_offset;
3708         u64 first_pos;
3709         u32 nritems;
3710         int nr_scaned = 0;
3711         int extent_locked = 0;
3712         int extent_type;
3713         int ret;
3714
3715         memcpy(&key, leaf_key, sizeof(key));
3716         first_pos = INT_LIMIT(loff_t) - extent_key->offset;
3717         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
3718                 if (key.objectid < ref_path->owner_objectid ||
3719                     (key.objectid == ref_path->owner_objectid &&
3720                      key.type < BTRFS_EXTENT_DATA_KEY)) {
3721                         key.objectid = ref_path->owner_objectid;
3722                         key.type = BTRFS_EXTENT_DATA_KEY;
3723                         key.offset = 0;
3724                 }
3725         }
3726
3727         while (1) {
3728                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
3729                 if (ret < 0)
3730                         goto out;
3731
3732                 leaf = path->nodes[0];
3733                 nritems = btrfs_header_nritems(leaf);
3734 next:
3735                 if (extent_locked && ret > 0) {
3736                         /*
3737                          * the file extent item was modified by someone
3738                          * before the extent got locked.
3739                          */
3740                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
3741                                       lock_end, GFP_NOFS);
3742                         extent_locked = 0;
3743                 }
3744
3745                 if (path->slots[0] >= nritems) {
3746                         if (++nr_scaned > 2)
3747                                 break;
3748
3749                         BUG_ON(extent_locked);
3750                         ret = btrfs_next_leaf(root, path);
3751                         if (ret < 0)
3752                                 goto out;
3753                         if (ret > 0)
3754                                 break;
3755                         leaf = path->nodes[0];
3756                         nritems = btrfs_header_nritems(leaf);
3757                 }
3758
3759                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3760
3761                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
3762                         if ((key.objectid > ref_path->owner_objectid) ||
3763                             (key.objectid == ref_path->owner_objectid &&
3764                              key.type > BTRFS_EXTENT_DATA_KEY) ||
3765                             (key.offset >= first_pos + extent_key->offset))
3766                                 break;
3767                 }
3768
3769                 if (inode && key.objectid != inode->i_ino) {
3770                         BUG_ON(extent_locked);
3771                         btrfs_release_path(root, path);
3772                         mutex_unlock(&inode->i_mutex);
3773                         iput(inode);
3774                         inode = NULL;
3775                         continue;
3776                 }
3777
3778                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
3779                         path->slots[0]++;
3780                         ret = 1;
3781                         goto next;
3782                 }
3783                 fi = btrfs_item_ptr(leaf, path->slots[0],
3784                                     struct btrfs_file_extent_item);
3785                 extent_type = btrfs_file_extent_type(leaf, fi);
3786                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
3787                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
3788                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3789                      extent_key->objectid)) {
3790                         path->slots[0]++;
3791                         ret = 1;
3792                         goto next;
3793                 }
3794
3795                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
3796                 ext_offset = btrfs_file_extent_offset(leaf, fi);
3797
3798                 if (first_pos > key.offset - ext_offset)
3799                         first_pos = key.offset - ext_offset;
3800
3801                 if (!extent_locked) {
3802                         lock_start = key.offset;
3803                         lock_end = lock_start + num_bytes - 1;
3804                 } else {
3805                         if (lock_start > key.offset ||
3806                             lock_end + 1 < key.offset + num_bytes) {
3807                                 unlock_extent(&BTRFS_I(inode)->io_tree,
3808                                               lock_start, lock_end, GFP_NOFS);
3809                                 extent_locked = 0;
3810                         }
3811                 }
3812
3813                 if (!inode) {
3814                         btrfs_release_path(root, path);
3815
3816                         inode = btrfs_iget_locked(root->fs_info->sb,
3817                                                   key.objectid, root);
3818                         if (inode->i_state & I_NEW) {
3819                                 BTRFS_I(inode)->root = root;
3820                                 BTRFS_I(inode)->location.objectid =
3821                                         key.objectid;
3822                                 BTRFS_I(inode)->location.type =
3823                                         BTRFS_INODE_ITEM_KEY;
3824                                 BTRFS_I(inode)->location.offset = 0;
3825                                 btrfs_read_locked_inode(inode);
3826                                 unlock_new_inode(inode);
3827                         }
3828                         /*
3829                          * some code call btrfs_commit_transaction while
3830                          * holding the i_mutex, so we can't use mutex_lock
3831                          * here.
3832                          */
3833                         if (is_bad_inode(inode) ||
3834                             !mutex_trylock(&inode->i_mutex)) {
3835                                 iput(inode);
3836                                 inode = NULL;
3837                                 key.offset = (u64)-1;
3838                                 goto skip;
3839                         }
3840                 }
3841
3842                 if (!extent_locked) {
3843                         struct btrfs_ordered_extent *ordered;
3844
3845                         btrfs_release_path(root, path);
3846
3847                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
3848                                     lock_end, GFP_NOFS);
3849                         ordered = btrfs_lookup_first_ordered_extent(inode,
3850                                                                     lock_end);
3851                         if (ordered &&
3852                             ordered->file_offset <= lock_end &&
3853                             ordered->file_offset + ordered->len > lock_start) {
3854                                 unlock_extent(&BTRFS_I(inode)->io_tree,
3855                                               lock_start, lock_end, GFP_NOFS);
3856                                 btrfs_start_ordered_extent(inode, ordered, 1);
3857                                 btrfs_put_ordered_extent(ordered);
3858                                 key.offset += num_bytes;
3859                                 goto skip;
3860                         }
3861                         if (ordered)
3862                                 btrfs_put_ordered_extent(ordered);
3863
3864                         extent_locked = 1;
3865                         continue;
3866                 }
3867
3868                 if (nr_extents == 1) {
3869                         /* update extent pointer in place */
3870                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
3871                                                 new_extents[0].disk_bytenr);
3872                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
3873                                                 new_extents[0].disk_num_bytes);
3874                         btrfs_mark_buffer_dirty(leaf);
3875
3876                         btrfs_drop_extent_cache(inode, key.offset,
3877                                                 key.offset + num_bytes - 1, 0);
3878
3879                         ret = btrfs_inc_extent_ref(trans, root,
3880                                                 new_extents[0].disk_bytenr,
3881                                                 new_extents[0].disk_num_bytes,
3882                                                 leaf->start,
3883                                                 root->root_key.objectid,
3884                                                 trans->transid,
3885                                                 key.objectid);
3886                         BUG_ON(ret);
3887
3888                         ret = btrfs_free_extent(trans, root,
3889                                                 extent_key->objectid,
3890                                                 extent_key->offset,
3891                                                 leaf->start,
3892                                                 btrfs_header_owner(leaf),
3893                                                 btrfs_header_generation(leaf),
3894                                                 key.objectid, 0);
3895                         BUG_ON(ret);
3896
3897                         btrfs_release_path(root, path);
3898                         key.offset += num_bytes;
3899                 } else {
3900                         BUG_ON(1);
3901 #if 0
3902                         u64 alloc_hint;
3903                         u64 extent_len;
3904                         int i;
3905                         /*
3906                          * drop old extent pointer at first, then insert the
3907                          * new pointers one bye one
3908                          */
3909                         btrfs_release_path(root, path);
3910                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
3911                                                  key.offset + num_bytes,
3912                                                  key.offset, &alloc_hint);
3913                         BUG_ON(ret);
3914
3915                         for (i = 0; i < nr_extents; i++) {
3916                                 if (ext_offset >= new_extents[i].num_bytes) {
3917                                         ext_offset -= new_extents[i].num_bytes;
3918                                         continue;
3919                                 }
3920                                 extent_len = min(new_extents[i].num_bytes -
3921                                                  ext_offset, num_bytes);
3922
3923                                 ret = btrfs_insert_empty_item(trans, root,
3924                                                               path, &key,
3925                                                               sizeof(*fi));
3926                                 BUG_ON(ret);
3927
3928                                 leaf = path->nodes[0];
3929                                 fi = btrfs_item_ptr(leaf, path->slots[0],
3930                                                 struct btrfs_file_extent_item);
3931                                 btrfs_set_file_extent_generation(leaf, fi,
3932                                                         trans->transid);
3933                                 btrfs_set_file_extent_type(leaf, fi,
3934                                                         BTRFS_FILE_EXTENT_REG);
3935                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
3936                                                 new_extents[i].disk_bytenr);
3937                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
3938                                                 new_extents[i].disk_num_bytes);
3939                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
3940                                                 new_extents[i].ram_bytes);
3941
3942                                 btrfs_set_file_extent_compression(leaf, fi,
3943                                                 new_extents[i].compression);
3944                                 btrfs_set_file_extent_encryption(leaf, fi,
3945                                                 new_extents[i].encryption);
3946                                 btrfs_set_file_extent_other_encoding(leaf, fi,
3947                                                 new_extents[i].other_encoding);
3948
3949                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3950                                                         extent_len);
3951                                 ext_offset += new_extents[i].offset;
3952                                 btrfs_set_file_extent_offset(leaf, fi,
3953                                                         ext_offset);
3954                                 btrfs_mark_buffer_dirty(leaf);
3955
3956                                 btrfs_drop_extent_cache(inode, key.offset,
3957                                                 key.offset + extent_len - 1, 0);
3958
3959                                 ret = btrfs_inc_extent_ref(trans, root,
3960                                                 new_extents[i].disk_bytenr,
3961                                                 new_extents[i].disk_num_bytes,
3962                                                 leaf->start,
3963                                                 root->root_key.objectid,
3964                                                 trans->transid, key.objectid);
3965                                 BUG_ON(ret);
3966                                 btrfs_release_path(root, path);
3967
3968                                 inode_add_bytes(inode, extent_len);
3969
3970                                 ext_offset = 0;
3971                                 num_bytes -= extent_len;
3972                                 key.offset += extent_len;
3973
3974                                 if (num_bytes == 0)
3975                                         break;
3976                         }
3977                         BUG_ON(i >= nr_extents);
3978 #endif
3979                 }
3980
3981                 if (extent_locked) {
3982                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
3983                                       lock_end, GFP_NOFS);
3984                         extent_locked = 0;
3985                 }
3986 skip:
3987                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
3988                     key.offset >= first_pos + extent_key->offset)
3989                         break;
3990
3991                 cond_resched();
3992         }
3993         ret = 0;
3994 out:
3995         btrfs_release_path(root, path);
3996         if (inode) {
3997                 mutex_unlock(&inode->i_mutex);
3998                 if (extent_locked) {
3999                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4000                                       lock_end, GFP_NOFS);
4001                 }
4002                 iput(inode);
4003         }
4004         return ret;
4005 }
4006
4007 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
4008                                struct btrfs_root *root,
4009                                struct extent_buffer *buf, u64 orig_start)
4010 {
4011         int level;
4012         int ret;
4013
4014         BUG_ON(btrfs_header_generation(buf) != trans->transid);
4015         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
4016
4017         level = btrfs_header_level(buf);
4018         if (level == 0) {
4019                 struct btrfs_leaf_ref *ref;
4020                 struct btrfs_leaf_ref *orig_ref;
4021
4022                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
4023                 if (!orig_ref)
4024                         return -ENOENT;
4025
4026                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
4027                 if (!ref) {
4028                         btrfs_free_leaf_ref(root, orig_ref);
4029                         return -ENOMEM;
4030                 }
4031
4032                 ref->nritems = orig_ref->nritems;
4033                 memcpy(ref->extents, orig_ref->extents,
4034                         sizeof(ref->extents[0]) * ref->nritems);
4035
4036                 btrfs_free_leaf_ref(root, orig_ref);
4037
4038                 ref->root_gen = trans->transid;
4039                 ref->bytenr = buf->start;
4040                 ref->owner = btrfs_header_owner(buf);
4041                 ref->generation = btrfs_header_generation(buf);
4042                 ret = btrfs_add_leaf_ref(root, ref, 0);
4043                 WARN_ON(ret);
4044                 btrfs_free_leaf_ref(root, ref);
4045         }
4046         return 0;
4047 }
4048
4049 static int noinline invalidate_extent_cache(struct btrfs_root *root,
4050                                         struct extent_buffer *leaf,
4051                                         struct btrfs_block_group_cache *group,
4052                                         struct btrfs_root *target_root)
4053 {
4054         struct btrfs_key key;
4055         struct inode *inode = NULL;
4056         struct btrfs_file_extent_item *fi;
4057         u64 num_bytes;
4058         u64 skip_objectid = 0;
4059         u32 nritems;
4060         u32 i;
4061
4062         nritems = btrfs_header_nritems(leaf);
4063         for (i = 0; i < nritems; i++) {
4064                 btrfs_item_key_to_cpu(leaf, &key, i);
4065                 if (key.objectid == skip_objectid ||
4066                     key.type != BTRFS_EXTENT_DATA_KEY)
4067                         continue;
4068                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4069                 if (btrfs_file_extent_type(leaf, fi) ==
4070                     BTRFS_FILE_EXTENT_INLINE)
4071                         continue;
4072                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4073                         continue;
4074                 if (!inode || inode->i_ino != key.objectid) {
4075                         iput(inode);
4076                         inode = btrfs_ilookup(target_root->fs_info->sb,
4077                                               key.objectid, target_root, 1);
4078                 }
4079                 if (!inode) {
4080                         skip_objectid = key.objectid;
4081                         continue;
4082                 }
4083                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4084
4085                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4086                             key.offset + num_bytes - 1, GFP_NOFS);
4087                 btrfs_drop_extent_cache(inode, key.offset,
4088                                         key.offset + num_bytes - 1, 1);
4089                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4090                               key.offset + num_bytes - 1, GFP_NOFS);
4091                 cond_resched();
4092         }
4093         iput(inode);
4094         return 0;
4095 }
4096
4097 static int noinline replace_extents_in_leaf(struct btrfs_trans_handle *trans,
4098                                         struct btrfs_root *root,
4099                                         struct extent_buffer *leaf,
4100                                         struct btrfs_block_group_cache *group,
4101                                         struct inode *reloc_inode)
4102 {
4103         struct btrfs_key key;
4104         struct btrfs_key extent_key;
4105         struct btrfs_file_extent_item *fi;
4106         struct btrfs_leaf_ref *ref;
4107         struct disk_extent *new_extent;
4108         u64 bytenr;
4109         u64 num_bytes;
4110         u32 nritems;
4111         u32 i;
4112         int ext_index;
4113         int nr_extent;
4114         int ret;
4115
4116         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
4117         BUG_ON(!new_extent);
4118
4119         ref = btrfs_lookup_leaf_ref(root, leaf->start);
4120         BUG_ON(!ref);
4121
4122         ext_index = -1;
4123         nritems = btrfs_header_nritems(leaf);
4124         for (i = 0; i < nritems; i++) {
4125                 btrfs_item_key_to_cpu(leaf, &key, i);
4126                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
4127                         continue;
4128                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4129                 if (btrfs_file_extent_type(leaf, fi) ==
4130                     BTRFS_FILE_EXTENT_INLINE)
4131                         continue;
4132                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
4133                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
4134                 if (bytenr == 0)
4135                         continue;
4136
4137                 ext_index++;
4138                 if (bytenr >= group->key.objectid + group->key.offset ||
4139                     bytenr + num_bytes <= group->key.objectid)
4140                         continue;
4141
4142                 extent_key.objectid = bytenr;
4143                 extent_key.offset = num_bytes;
4144                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4145                 nr_extent = 1;
4146                 ret = get_new_locations(reloc_inode, &extent_key,
4147                                         group->key.objectid, 1,
4148                                         &new_extent, &nr_extent);
4149                 if (ret > 0)
4150                         continue;
4151                 BUG_ON(ret < 0);
4152
4153                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
4154                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
4155                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
4156                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
4157
4158                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4159                                                 new_extent->disk_bytenr);
4160                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4161                                                 new_extent->disk_num_bytes);
4162                 btrfs_mark_buffer_dirty(leaf);
4163
4164                 ret = btrfs_inc_extent_ref(trans, root,
4165                                         new_extent->disk_bytenr,
4166                                         new_extent->disk_num_bytes,
4167                                         leaf->start,
4168                                         root->root_key.objectid,
4169                                         trans->transid, key.objectid);
4170                 BUG_ON(ret);
4171                 ret = btrfs_free_extent(trans, root,
4172                                         bytenr, num_bytes, leaf->start,
4173                                         btrfs_header_owner(leaf),
4174                                         btrfs_header_generation(leaf),
4175                                         key.objectid, 0);
4176                 BUG_ON(ret);
4177                 cond_resched();
4178         }
4179         kfree(new_extent);
4180         BUG_ON(ext_index + 1 != ref->nritems);
4181         btrfs_free_leaf_ref(root, ref);
4182         return 0;
4183 }
4184
4185 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
4186                           struct btrfs_root *root)
4187 {
4188         struct btrfs_root *reloc_root;
4189         int ret;
4190
4191         if (root->reloc_root) {
4192                 reloc_root = root->reloc_root;
4193                 root->reloc_root = NULL;
4194                 list_add(&reloc_root->dead_list,
4195                          &root->fs_info->dead_reloc_roots);
4196
4197                 btrfs_set_root_bytenr(&reloc_root->root_item,
4198                                       reloc_root->node->start);
4199                 btrfs_set_root_level(&root->root_item,
4200                                      btrfs_header_level(reloc_root->node));
4201                 memset(&reloc_root->root_item.drop_progress, 0,
4202                         sizeof(struct btrfs_disk_key));
4203                 reloc_root->root_item.drop_level = 0;
4204
4205                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4206                                         &reloc_root->root_key,
4207                                         &reloc_root->root_item);
4208                 BUG_ON(ret);
4209         }
4210         return 0;
4211 }
4212
4213 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
4214 {
4215         struct btrfs_trans_handle *trans;
4216         struct btrfs_root *reloc_root;
4217         struct btrfs_root *prev_root = NULL;
4218         struct list_head dead_roots;
4219         int ret;
4220         unsigned long nr;
4221
4222         INIT_LIST_HEAD(&dead_roots);
4223         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
4224
4225         while (!list_empty(&dead_roots)) {
4226                 reloc_root = list_entry(dead_roots.prev,
4227                                         struct btrfs_root, dead_list);
4228                 list_del_init(&reloc_root->dead_list);
4229
4230                 BUG_ON(reloc_root->commit_root != NULL);
4231                 while (1) {
4232                         trans = btrfs_join_transaction(root, 1);
4233                         BUG_ON(!trans);
4234
4235                         mutex_lock(&root->fs_info->drop_mutex);
4236                         ret = btrfs_drop_snapshot(trans, reloc_root);
4237                         if (ret != -EAGAIN)
4238                                 break;
4239                         mutex_unlock(&root->fs_info->drop_mutex);
4240
4241                         nr = trans->blocks_used;
4242                         ret = btrfs_end_transaction(trans, root);
4243                         BUG_ON(ret);
4244                         btrfs_btree_balance_dirty(root, nr);
4245                 }
4246
4247                 free_extent_buffer(reloc_root->node);
4248
4249                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
4250                                      &reloc_root->root_key);
4251                 BUG_ON(ret);
4252                 mutex_unlock(&root->fs_info->drop_mutex);
4253
4254                 nr = trans->blocks_used;
4255                 ret = btrfs_end_transaction(trans, root);
4256                 BUG_ON(ret);
4257                 btrfs_btree_balance_dirty(root, nr);
4258
4259                 kfree(prev_root);
4260                 prev_root = reloc_root;
4261         }
4262         if (prev_root) {
4263                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
4264                 kfree(prev_root);
4265         }
4266         return 0;
4267 }
4268
4269 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
4270 {
4271         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
4272         return 0;
4273 }
4274
4275 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
4276 {
4277         struct btrfs_root *reloc_root;
4278         struct btrfs_trans_handle *trans;
4279         struct btrfs_key location;
4280         int found;
4281         int ret;
4282
4283         mutex_lock(&root->fs_info->tree_reloc_mutex);
4284         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
4285         BUG_ON(ret);
4286         found = !list_empty(&root->fs_info->dead_reloc_roots);
4287         mutex_unlock(&root->fs_info->tree_reloc_mutex);
4288
4289         if (found) {
4290                 trans = btrfs_start_transaction(root, 1);
4291                 BUG_ON(!trans);
4292                 ret = btrfs_commit_transaction(trans, root);
4293                 BUG_ON(ret);
4294         }
4295
4296         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
4297         location.offset = (u64)-1;
4298         location.type = BTRFS_ROOT_ITEM_KEY;
4299
4300         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
4301         BUG_ON(!reloc_root);
4302         btrfs_orphan_cleanup(reloc_root);
4303         return 0;
4304 }
4305
4306 static int noinline init_reloc_tree(struct btrfs_trans_handle *trans,
4307                                     struct btrfs_root *root)
4308 {
4309         struct btrfs_root *reloc_root;
4310         struct extent_buffer *eb;
4311         struct btrfs_root_item *root_item;
4312         struct btrfs_key root_key;
4313         int ret;
4314
4315         BUG_ON(!root->ref_cows);
4316         if (root->reloc_root)
4317                 return 0;
4318
4319         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
4320         BUG_ON(!root_item);
4321
4322         ret = btrfs_copy_root(trans, root, root->commit_root,
4323                               &eb, BTRFS_TREE_RELOC_OBJECTID);
4324         BUG_ON(ret);
4325
4326         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4327         root_key.offset = root->root_key.objectid;
4328         root_key.type = BTRFS_ROOT_ITEM_KEY;
4329
4330         memcpy(root_item, &root->root_item, sizeof(root_item));
4331         btrfs_set_root_refs(root_item, 0);
4332         btrfs_set_root_bytenr(root_item, eb->start);
4333         btrfs_set_root_level(root_item, btrfs_header_level(eb));
4334         btrfs_set_root_generation(root_item, trans->transid);
4335
4336         btrfs_tree_unlock(eb);
4337         free_extent_buffer(eb);
4338
4339         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
4340                                 &root_key, root_item);
4341         BUG_ON(ret);
4342         kfree(root_item);
4343
4344         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
4345                                                  &root_key);
4346         BUG_ON(!reloc_root);
4347         reloc_root->last_trans = trans->transid;
4348         reloc_root->commit_root = NULL;
4349         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
4350
4351         root->reloc_root = reloc_root;
4352         return 0;
4353 }
4354
4355 /*
4356  * Core function of space balance.
4357  *
4358  * The idea is using reloc trees to relocate tree blocks in reference
4359  * counted roots. There is one reloc tree for each subvol, and all
4360  * reloc trees share same root key objectid. Reloc trees are snapshots
4361  * of the latest committed roots of subvols (root->commit_root).
4362  *
4363  * To relocate a tree block referenced by a subvol, there are two steps.
4364  * COW the block through subvol's reloc tree, then update block pointer
4365  * in the subvol to point to the new block. Since all reloc trees share
4366  * same root key objectid, doing special handing for tree blocks owned
4367  * by them is easy. Once a tree block has been COWed in one reloc tree,
4368  * we can use the resulting new block directly when the same block is
4369  * required to COW again through other reloc trees. By this way, relocated
4370  * tree blocks are shared between reloc trees, so they are also shared
4371  * between subvols.
4372  */
4373 static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
4374                                       struct btrfs_root *root,
4375                                       struct btrfs_path *path,
4376                                       struct btrfs_key *first_key,
4377                                       struct btrfs_ref_path *ref_path,
4378                                       struct btrfs_block_group_cache *group,
4379                                       struct inode *reloc_inode)
4380 {
4381         struct btrfs_root *reloc_root;
4382         struct extent_buffer *eb = NULL;
4383         struct btrfs_key *keys;
4384         u64 *nodes;
4385         int level;
4386         int shared_level;
4387         int lowest_level = 0;
4388         int ret;
4389
4390         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
4391                 lowest_level = ref_path->owner_objectid;
4392
4393         if (!root->ref_cows) {
4394                 path->lowest_level = lowest_level;
4395                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
4396                 BUG_ON(ret < 0);
4397                 path->lowest_level = 0;
4398                 btrfs_release_path(root, path);
4399                 return 0;
4400         }
4401
4402         mutex_lock(&root->fs_info->tree_reloc_mutex);
4403         ret = init_reloc_tree(trans, root);
4404         BUG_ON(ret);
4405         reloc_root = root->reloc_root;
4406
4407         shared_level = ref_path->shared_level;
4408         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
4409
4410         keys = ref_path->node_keys;
4411         nodes = ref_path->new_nodes;
4412         memset(&keys[shared_level + 1], 0,
4413                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
4414         memset(&nodes[shared_level + 1], 0,
4415                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
4416
4417         if (nodes[lowest_level] == 0) {
4418                 path->lowest_level = lowest_level;
4419                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
4420                                         0, 1);
4421                 BUG_ON(ret);
4422                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
4423                         eb = path->nodes[level];
4424                         if (!eb || eb == reloc_root->node)
4425                                 break;
4426                         nodes[level] = eb->start;
4427                         if (level == 0)
4428                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
4429                         else
4430                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
4431                 }
4432                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4433                         eb = path->nodes[0];
4434                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
4435                                                       group, reloc_inode);
4436                         BUG_ON(ret);
4437                 }
4438                 btrfs_release_path(reloc_root, path);
4439         } else {
4440                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
4441                                        lowest_level);
4442                 BUG_ON(ret);
4443         }
4444
4445         /*
4446          * replace tree blocks in the fs tree with tree blocks in
4447          * the reloc tree.
4448          */
4449         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
4450         BUG_ON(ret < 0);
4451
4452         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4453                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
4454                                         0, 0);
4455                 BUG_ON(ret);
4456                 extent_buffer_get(path->nodes[0]);
4457                 eb = path->nodes[0];
4458                 btrfs_release_path(reloc_root, path);
4459                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
4460                 BUG_ON(ret);
4461                 free_extent_buffer(eb);
4462         }
4463
4464         mutex_unlock(&root->fs_info->tree_reloc_mutex);
4465         path->lowest_level = 0;
4466         return 0;
4467 }
4468
4469 static int noinline relocate_tree_block(struct btrfs_trans_handle *trans,
4470                                         struct btrfs_root *root,
4471                                         struct btrfs_path *path,
4472                                         struct btrfs_key *first_key,
4473                                         struct btrfs_ref_path *ref_path)
4474 {
4475         int ret;
4476
4477         ret = relocate_one_path(trans, root, path, first_key,
4478                                 ref_path, NULL, NULL);
4479         BUG_ON(ret);
4480
4481         if (root == root->fs_info->extent_root)
4482                 btrfs_extent_post_op(trans, root);
4483
4484         return 0;
4485 }
4486
4487 static int noinline del_extent_zero(struct btrfs_trans_handle *trans,
4488                                     struct btrfs_root *extent_root,
4489                                     struct btrfs_path *path,
4490                                     struct btrfs_key *extent_key)
4491 {
4492         int ret;
4493
4494         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
4495         if (ret)
4496                 goto out;
4497         ret = btrfs_del_item(trans, extent_root, path);
4498 out:
4499         btrfs_release_path(extent_root, path);
4500         return ret;
4501 }
4502
4503 static struct btrfs_root noinline *read_ref_root(struct btrfs_fs_info *fs_info,
4504                                                 struct btrfs_ref_path *ref_path)
4505 {
4506         struct btrfs_key root_key;
4507
4508         root_key.objectid = ref_path->root_objectid;
4509         root_key.type = BTRFS_ROOT_ITEM_KEY;
4510         if (is_cowonly_root(ref_path->root_objectid))
4511                 root_key.offset = 0;
4512         else
4513                 root_key.offset = (u64)-1;
4514
4515         return btrfs_read_fs_root_no_name(fs_info, &root_key);
4516 }
4517
4518 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
4519                                         struct btrfs_path *path,
4520                                         struct btrfs_key *extent_key,
4521                                         struct btrfs_block_group_cache *group,
4522                                         struct inode *reloc_inode, int pass)
4523 {
4524         struct btrfs_trans_handle *trans;
4525         struct btrfs_root *found_root;
4526         struct btrfs_ref_path *ref_path = NULL;
4527         struct disk_extent *new_extents = NULL;
4528         int nr_extents = 0;
4529         int loops;
4530         int ret;
4531         int level;
4532         struct btrfs_key first_key;
4533         u64 prev_block = 0;
4534
4535
4536         trans = btrfs_start_transaction(extent_root, 1);
4537         BUG_ON(!trans);
4538
4539         if (extent_key->objectid == 0) {
4540                 ret = del_extent_zero(trans, extent_root, path, extent_key);
4541                 goto out;
4542         }
4543
4544         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
4545         if (!ref_path) {
4546                ret = -ENOMEM;
4547                goto out;
4548         }
4549
4550         for (loops = 0; ; loops++) {
4551                 if (loops == 0) {
4552                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
4553                                                    extent_key->objectid);
4554                 } else {
4555                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
4556                 }
4557                 if (ret < 0)
4558                         goto out;
4559                 if (ret > 0)
4560                         break;
4561
4562                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
4563                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
4564                         continue;
4565
4566                 found_root = read_ref_root(extent_root->fs_info, ref_path);
4567                 BUG_ON(!found_root);
4568                 /*
4569                  * for reference counted tree, only process reference paths
4570                  * rooted at the latest committed root.
4571                  */
4572                 if (found_root->ref_cows &&
4573                     ref_path->root_generation != found_root->root_key.offset)
4574                         continue;
4575
4576                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4577                         if (pass == 0) {
4578                                 /*
4579                                  * copy data extents to new locations
4580                                  */
4581                                 u64 group_start = group->key.objectid;
4582                                 ret = relocate_data_extent(reloc_inode,
4583                                                            extent_key,
4584                                                            group_start);
4585                                 if (ret < 0)
4586                                         goto out;
4587                                 break;
4588                         }
4589                         level = 0;
4590                 } else {
4591                         level = ref_path->owner_objectid;
4592                 }
4593
4594                 if (prev_block != ref_path->nodes[level]) {
4595                         struct extent_buffer *eb;
4596                         u64 block_start = ref_path->nodes[level];
4597                         u64 block_size = btrfs_level_size(found_root, level);
4598
4599                         eb = read_tree_block(found_root, block_start,
4600                                              block_size, 0);
4601                         btrfs_tree_lock(eb);
4602                         BUG_ON(level != btrfs_header_level(eb));
4603
4604                         if (level == 0)
4605                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
4606                         else
4607                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
4608
4609                         btrfs_tree_unlock(eb);
4610                         free_extent_buffer(eb);
4611                         prev_block = block_start;
4612                 }
4613
4614                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
4615                     pass >= 2) {
4616                         /*
4617                          * use fallback method to process the remaining
4618                          * references.
4619                          */
4620                         if (!new_extents) {
4621                                 u64 group_start = group->key.objectid;
4622                                 new_extents = kmalloc(sizeof(*new_extents),
4623                                                       GFP_NOFS);
4624                                 nr_extents = 1;
4625                                 ret = get_new_locations(reloc_inode,
4626                                                         extent_key,
4627                                                         group_start, 1,
4628                                                         &new_extents,
4629                                                         &nr_extents);
4630                                 if (ret)
4631                                         goto out;
4632                         }
4633                         btrfs_record_root_in_trans(found_root);
4634                         ret = replace_one_extent(trans, found_root,
4635                                                 path, extent_key,
4636                                                 &first_key, ref_path,
4637                                                 new_extents, nr_extents);
4638                         if (ret < 0)
4639                                 goto out;
4640                         continue;
4641                 }
4642
4643                 btrfs_record_root_in_trans(found_root);
4644                 if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4645                         ret = relocate_tree_block(trans, found_root, path,
4646                                                   &first_key, ref_path);
4647                 } else {
4648                         /*
4649                          * try to update data extent references while
4650                          * keeping metadata shared between snapshots.
4651                          */
4652                         ret = relocate_one_path(trans, found_root, path,
4653                                                 &first_key, ref_path,
4654                                                 group, reloc_inode);
4655                 }
4656                 if (ret < 0)
4657                         goto out;
4658         }
4659         ret = 0;
4660 out:
4661         btrfs_end_transaction(trans, extent_root);
4662         kfree(new_extents);
4663         kfree(ref_path);
4664         return ret;
4665 }
4666
4667 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
4668 {
4669         u64 num_devices;
4670         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
4671                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
4672
4673         num_devices = root->fs_info->fs_devices->num_devices;
4674         if (num_devices == 1) {
4675                 stripped |= BTRFS_BLOCK_GROUP_DUP;
4676                 stripped = flags & ~stripped;
4677
4678                 /* turn raid0 into single device chunks */
4679                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
4680                         return stripped;
4681
4682                 /* turn mirroring into duplication */
4683                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
4684                              BTRFS_BLOCK_GROUP_RAID10))
4685                         return stripped | BTRFS_BLOCK_GROUP_DUP;
4686                 return flags;
4687         } else {
4688                 /* they already had raid on here, just return */
4689                 if (flags & stripped)
4690                         return flags;
4691
4692                 stripped |= BTRFS_BLOCK_GROUP_DUP;
4693                 stripped = flags & ~stripped;
4694
4695                 /* switch duplicated blocks with raid1 */
4696                 if (flags & BTRFS_BLOCK_GROUP_DUP)
4697                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
4698
4699                 /* turn single device chunks into raid0 */
4700                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
4701         }
4702         return flags;
4703 }
4704
4705 int __alloc_chunk_for_shrink(struct btrfs_root *root,
4706                      struct btrfs_block_group_cache *shrink_block_group,
4707                      int force)
4708 {
4709         struct btrfs_trans_handle *trans;
4710         u64 new_alloc_flags;
4711         u64 calc;
4712
4713         spin_lock(&shrink_block_group->lock);
4714         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
4715                 spin_unlock(&shrink_block_group->lock);
4716
4717                 trans = btrfs_start_transaction(root, 1);
4718                 spin_lock(&shrink_block_group->lock);
4719
4720                 new_alloc_flags = update_block_group_flags(root,
4721                                                    shrink_block_group->flags);
4722                 if (new_alloc_flags != shrink_block_group->flags) {
4723                         calc =
4724                              btrfs_block_group_used(&shrink_block_group->item);
4725                 } else {
4726                         calc = shrink_block_group->key.offset;
4727                 }
4728                 spin_unlock(&shrink_block_group->lock);
4729
4730                 do_chunk_alloc(trans, root->fs_info->extent_root,
4731                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
4732
4733                 btrfs_end_transaction(trans, root);
4734         } else
4735                 spin_unlock(&shrink_block_group->lock);
4736         return 0;
4737 }
4738
4739 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4740                                  struct btrfs_root *root,
4741                                  u64 objectid, u64 size)
4742 {
4743         struct btrfs_path *path;
4744         struct btrfs_inode_item *item;
4745         struct extent_buffer *leaf;
4746         int ret;
4747
4748         path = btrfs_alloc_path();
4749         if (!path)
4750                 return -ENOMEM;
4751
4752         ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4753         if (ret)
4754                 goto out;
4755
4756         leaf = path->nodes[0];
4757         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4758         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4759         btrfs_set_inode_generation(leaf, item, 1);
4760         btrfs_set_inode_size(leaf, item, size);
4761         btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4762         btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NODATASUM |
4763                                           BTRFS_INODE_NOCOMPRESS);
4764         btrfs_mark_buffer_dirty(leaf);
4765         btrfs_release_path(root, path);
4766 out:
4767         btrfs_free_path(path);
4768         return ret;
4769 }
4770
4771 static struct inode noinline *create_reloc_inode(struct btrfs_fs_info *fs_info,
4772                                         struct btrfs_block_group_cache *group)
4773 {
4774         struct inode *inode = NULL;
4775         struct btrfs_trans_handle *trans;
4776         struct btrfs_root *root;
4777         struct btrfs_key root_key;
4778         u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4779         int err = 0;
4780
4781         root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
4782         root_key.type = BTRFS_ROOT_ITEM_KEY;
4783         root_key.offset = (u64)-1;
4784         root = btrfs_read_fs_root_no_name(fs_info, &root_key);
4785         if (IS_ERR(root))
4786                 return ERR_CAST(root);
4787
4788         trans = btrfs_start_transaction(root, 1);
4789         BUG_ON(!trans);
4790
4791         err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
4792         if (err)
4793                 goto out;
4794
4795         err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
4796         BUG_ON(err);
4797
4798         err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
4799                                        group->key.offset, 0, group->key.offset,
4800                                        0, 0, 0);
4801         BUG_ON(err);
4802
4803         inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
4804         if (inode->i_state & I_NEW) {
4805                 BTRFS_I(inode)->root = root;
4806                 BTRFS_I(inode)->location.objectid = objectid;
4807                 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
4808                 BTRFS_I(inode)->location.offset = 0;
4809                 btrfs_read_locked_inode(inode);
4810                 unlock_new_inode(inode);
4811                 BUG_ON(is_bad_inode(inode));
4812         } else {
4813                 BUG_ON(1);
4814         }
4815
4816         err = btrfs_orphan_add(trans, inode);
4817 out:
4818         btrfs_end_transaction(trans, root);
4819         if (err) {
4820                 if (inode)
4821                         iput(inode);
4822                 inode = ERR_PTR(err);
4823         }
4824         return inode;
4825 }
4826
4827 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
4828 {
4829         struct btrfs_trans_handle *trans;
4830         struct btrfs_path *path;
4831         struct btrfs_fs_info *info = root->fs_info;
4832         struct extent_buffer *leaf;
4833         struct inode *reloc_inode;
4834         struct btrfs_block_group_cache *block_group;
4835         struct btrfs_key key;
4836         u64 skipped;
4837         u64 cur_byte;
4838         u64 total_found;
4839         u32 nritems;
4840         int ret;
4841         int progress;
4842         int pass = 0;
4843
4844         root = root->fs_info->extent_root;
4845
4846         block_group = btrfs_lookup_block_group(info, group_start);
4847         BUG_ON(!block_group);
4848
4849         printk("btrfs relocating block group %llu flags %llu\n",
4850                (unsigned long long)block_group->key.objectid,
4851                (unsigned long long)block_group->flags);
4852
4853         path = btrfs_alloc_path();
4854         BUG_ON(!path);
4855
4856         reloc_inode = create_reloc_inode(info, block_group);
4857         BUG_ON(IS_ERR(reloc_inode));
4858
4859         __alloc_chunk_for_shrink(root, block_group, 1);
4860         block_group->ro = 1;
4861         block_group->space_info->total_bytes -= block_group->key.offset;
4862
4863         btrfs_start_delalloc_inodes(info->tree_root);
4864         btrfs_wait_ordered_extents(info->tree_root, 0);
4865 again:
4866         skipped = 0;
4867         total_found = 0;
4868         progress = 0;
4869         key.objectid = block_group->key.objectid;
4870         key.offset = 0;
4871         key.type = 0;
4872         cur_byte = key.objectid;
4873
4874         trans = btrfs_start_transaction(info->tree_root, 1);
4875         btrfs_commit_transaction(trans, info->tree_root);
4876
4877         mutex_lock(&root->fs_info->cleaner_mutex);
4878         btrfs_clean_old_snapshots(info->tree_root);
4879         btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
4880         mutex_unlock(&root->fs_info->cleaner_mutex);
4881
4882         while(1) {
4883                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4884                 if (ret < 0)
4885                         goto out;
4886 next:
4887                 leaf = path->nodes[0];
4888                 nritems = btrfs_header_nritems(leaf);
4889                 if (path->slots[0] >= nritems) {
4890                         ret = btrfs_next_leaf(root, path);
4891                         if (ret < 0)
4892                                 goto out;
4893                         if (ret == 1) {
4894                                 ret = 0;
4895                                 break;
4896                         }
4897                         leaf = path->nodes[0];
4898                         nritems = btrfs_header_nritems(leaf);
4899                 }
4900
4901                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4902
4903                 if (key.objectid >= block_group->key.objectid +
4904                     block_group->key.offset)
4905                         break;
4906
4907                 if (progress && need_resched()) {
4908                         btrfs_release_path(root, path);
4909                         cond_resched();
4910                         progress = 0;
4911                         continue;
4912                 }
4913                 progress = 1;
4914
4915                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
4916                     key.objectid + key.offset <= cur_byte) {
4917                         path->slots[0]++;
4918                         goto next;
4919                 }
4920
4921                 total_found++;
4922                 cur_byte = key.objectid + key.offset;
4923                 btrfs_release_path(root, path);
4924
4925                 __alloc_chunk_for_shrink(root, block_group, 0);
4926                 ret = relocate_one_extent(root, path, &key, block_group,
4927                                           reloc_inode, pass);
4928                 BUG_ON(ret < 0);
4929                 if (ret > 0)
4930                         skipped++;
4931
4932                 key.objectid = cur_byte;
4933                 key.type = 0;
4934                 key.offset = 0;
4935         }
4936
4937         btrfs_release_path(root, path);
4938
4939         if (pass == 0) {
4940                 btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
4941                 invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
4942                 WARN_ON(reloc_inode->i_mapping->nrpages);
4943         }
4944
4945         if (total_found > 0) {
4946                 printk("btrfs found %llu extents in pass %d\n",
4947                        (unsigned long long)total_found, pass);
4948                 pass++;
4949                 if (total_found == skipped && pass > 2) {
4950                         iput(reloc_inode);
4951                         reloc_inode = create_reloc_inode(info, block_group);
4952                         pass = 0;
4953                 }
4954                 goto again;
4955         }
4956
4957         /* delete reloc_inode */
4958         iput(reloc_inode);
4959
4960         /* unpin extents in this range */
4961         trans = btrfs_start_transaction(info->tree_root, 1);
4962         btrfs_commit_transaction(trans, info->tree_root);
4963
4964         spin_lock(&block_group->lock);
4965         WARN_ON(block_group->pinned > 0);
4966         WARN_ON(block_group->reserved > 0);
4967         WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
4968         spin_unlock(&block_group->lock);
4969         ret = 0;
4970 out:
4971         btrfs_free_path(path);
4972         return ret;
4973 }
4974
4975 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
4976                            struct btrfs_key *key)
4977 {
4978         int ret = 0;
4979         struct btrfs_key found_key;
4980         struct extent_buffer *leaf;
4981         int slot;
4982
4983         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
4984         if (ret < 0)
4985                 goto out;
4986
4987         while(1) {
4988                 slot = path->slots[0];
4989                 leaf = path->nodes[0];
4990                 if (slot >= btrfs_header_nritems(leaf)) {
4991                         ret = btrfs_next_leaf(root, path);
4992                         if (ret == 0)
4993                                 continue;
4994                         if (ret < 0)
4995                                 goto out;
4996                         break;
4997                 }
4998                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4999
5000                 if (found_key.objectid >= key->objectid &&
5001                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
5002                         ret = 0;
5003                         goto out;
5004                 }
5005                 path->slots[0]++;
5006         }
5007         ret = -ENOENT;
5008 out:
5009         return ret;
5010 }
5011
5012 int btrfs_free_block_groups(struct btrfs_fs_info *info)
5013 {
5014         struct btrfs_block_group_cache *block_group;
5015         struct rb_node *n;
5016
5017         spin_lock(&info->block_group_cache_lock);
5018         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
5019                 block_group = rb_entry(n, struct btrfs_block_group_cache,
5020                                        cache_node);
5021                 rb_erase(&block_group->cache_node,
5022                          &info->block_group_cache_tree);
5023                 spin_unlock(&info->block_group_cache_lock);
5024
5025                 btrfs_remove_free_space_cache(block_group);
5026                 down_write(&block_group->space_info->groups_sem);
5027                 list_del(&block_group->list);
5028                 up_write(&block_group->space_info->groups_sem);
5029                 kfree(block_group);
5030
5031                 spin_lock(&info->block_group_cache_lock);
5032         }
5033         spin_unlock(&info->block_group_cache_lock);
5034         return 0;
5035 }
5036
5037 int btrfs_read_block_groups(struct btrfs_root *root)
5038 {
5039         struct btrfs_path *path;
5040         int ret;
5041         struct btrfs_block_group_cache *cache;
5042         struct btrfs_fs_info *info = root->fs_info;
5043         struct btrfs_space_info *space_info;
5044         struct btrfs_key key;
5045         struct btrfs_key found_key;
5046         struct extent_buffer *leaf;
5047
5048         root = info->extent_root;
5049         key.objectid = 0;
5050         key.offset = 0;
5051         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
5052         path = btrfs_alloc_path();
5053         if (!path)
5054                 return -ENOMEM;
5055
5056         while(1) {
5057                 ret = find_first_block_group(root, path, &key);
5058                 if (ret > 0) {
5059                         ret = 0;
5060                         goto error;
5061                 }
5062                 if (ret != 0)
5063                         goto error;
5064
5065                 leaf = path->nodes[0];
5066                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5067                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
5068                 if (!cache) {
5069                         ret = -ENOMEM;
5070                         break;
5071                 }
5072
5073                 spin_lock_init(&cache->lock);
5074                 mutex_init(&cache->alloc_mutex);
5075                 INIT_LIST_HEAD(&cache->list);
5076                 read_extent_buffer(leaf, &cache->item,
5077                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
5078                                    sizeof(cache->item));
5079                 memcpy(&cache->key, &found_key, sizeof(found_key));
5080
5081                 key.objectid = found_key.objectid + found_key.offset;
5082                 btrfs_release_path(root, path);
5083                 cache->flags = btrfs_block_group_flags(&cache->item);
5084
5085                 ret = update_space_info(info, cache->flags, found_key.offset,
5086                                         btrfs_block_group_used(&cache->item),
5087                                         &space_info);
5088                 BUG_ON(ret);
5089                 cache->space_info = space_info;
5090                 down_write(&space_info->groups_sem);
5091                 list_add_tail(&cache->list, &space_info->block_groups);
5092                 up_write(&space_info->groups_sem);
5093
5094                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
5095                 BUG_ON(ret);
5096
5097                 set_avail_alloc_bits(root->fs_info, cache->flags);
5098         }
5099         ret = 0;
5100 error:
5101         btrfs_free_path(path);
5102         return ret;
5103 }
5104
5105 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
5106                            struct btrfs_root *root, u64 bytes_used,
5107                            u64 type, u64 chunk_objectid, u64 chunk_offset,
5108                            u64 size)
5109 {
5110         int ret;
5111         struct btrfs_root *extent_root;
5112         struct btrfs_block_group_cache *cache;
5113
5114         extent_root = root->fs_info->extent_root;
5115
5116         root->fs_info->last_trans_new_blockgroup = trans->transid;
5117
5118         cache = kzalloc(sizeof(*cache), GFP_NOFS);
5119         if (!cache)
5120                 return -ENOMEM;
5121
5122         cache->key.objectid = chunk_offset;
5123         cache->key.offset = size;
5124         spin_lock_init(&cache->lock);
5125         mutex_init(&cache->alloc_mutex);
5126         INIT_LIST_HEAD(&cache->list);
5127         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
5128
5129         btrfs_set_block_group_used(&cache->item, bytes_used);
5130         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
5131         cache->flags = type;
5132         btrfs_set_block_group_flags(&cache->item, type);
5133
5134         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
5135                                 &cache->space_info);
5136         BUG_ON(ret);
5137         down_write(&cache->space_info->groups_sem);
5138         list_add_tail(&cache->list, &cache->space_info->block_groups);
5139         up_write(&cache->space_info->groups_sem);
5140
5141         ret = btrfs_add_block_group_cache(root->fs_info, cache);
5142         BUG_ON(ret);
5143
5144         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
5145                                 sizeof(cache->item));
5146         BUG_ON(ret);
5147
5148         finish_current_insert(trans, extent_root, 0);
5149         ret = del_pending_extents(trans, extent_root, 0);
5150         BUG_ON(ret);
5151         set_avail_alloc_bits(extent_root->fs_info, type);
5152
5153         return 0;
5154 }
5155
5156 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
5157                              struct btrfs_root *root, u64 group_start)
5158 {
5159         struct btrfs_path *path;
5160         struct btrfs_block_group_cache *block_group;
5161         struct btrfs_key key;
5162         int ret;
5163
5164         root = root->fs_info->extent_root;
5165
5166         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
5167         BUG_ON(!block_group);
5168
5169         memcpy(&key, &block_group->key, sizeof(key));
5170
5171         path = btrfs_alloc_path();
5172         BUG_ON(!path);
5173
5174         btrfs_remove_free_space_cache(block_group);
5175         rb_erase(&block_group->cache_node,
5176                  &root->fs_info->block_group_cache_tree);
5177         down_write(&block_group->space_info->groups_sem);
5178         list_del(&block_group->list);
5179         up_write(&block_group->space_info->groups_sem);
5180
5181         /*
5182         memset(shrink_block_group, 0, sizeof(*shrink_block_group));
5183         kfree(shrink_block_group);
5184         */
5185
5186         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
5187         if (ret > 0)
5188                 ret = -EIO;
5189         if (ret < 0)
5190                 goto out;
5191
5192         ret = btrfs_del_item(trans, root, path);
5193 out:
5194         btrfs_free_path(path);
5195         return ret;
5196 }