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