SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include "hash.h"
  23 #include "crc32c.h"
  24 #include "ctree.h"
  25 #include "disk-io.h"
  26 #include "print-tree.h"
  27 #include "transaction.h"
  28 #include "volumes.h"
  29 #include "locking.h"
  30 #include "ref-cache.h"
  31
  32 #define PENDING_EXTENT_INSERT 0
  33 #define PENDING_EXTENT_DELETE 1
  34 #define PENDING_BACKREF_UPDATE 2
  35
  36 struct pending_extent_op {
  37         int type;
  38         u64 bytenr;
  39         u64 num_bytes;
  40         u64 parent;
  41         u64 orig_parent;
  42         u64 generation;
  43         u64 orig_generation;
  44         int level;
  45 };
  46
  47 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  48                                  btrfs_root *extent_root);
  49 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  50                                btrfs_root *extent_root);
  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);
 715         del_pending_extents(trans, extent_root);
 716 out:
 717         btrfs_free_path(path);
 718         return ret;
 719 }
 720
 721 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 722                             struct btrfs_root *root, u64 bytenr,
 723                             u64 orig_parent, u64 parent,
 724                             u64 ref_root, u64 ref_generation,
 725                             u64 owner_objectid)
 726 {
 727         int ret;
 728         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 729             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 730                 return 0;
 731         ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
 732                                         parent, ref_root, ref_root,
 733                                         ref_generation, ref_generation,
 734                                         owner_objectid);
 735         return ret;
 736 }
 737
 738 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 739                                   struct btrfs_root *root, u64 bytenr,
 740                                   u64 orig_parent, u64 parent,
 741                                   u64 orig_root, u64 ref_root,
 742                                   u64 orig_generation, u64 ref_generation,
 743                                   u64 owner_objectid)
 744 {
 745         struct btrfs_path *path;
 746         int ret;
 747         struct btrfs_key key;
 748         struct extent_buffer *l;
 749         struct btrfs_extent_item *item;
 750         u32 refs;
 751
 752         path = btrfs_alloc_path();
 753         if (!path)
 754                 return -ENOMEM;
 755
 756         path->reada = 1;
 757         key.objectid = bytenr;
 758         key.type = BTRFS_EXTENT_ITEM_KEY;
 759         key.offset = (u64)-1;
 760
 761         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 762                                 0, 1);
 763         if (ret < 0)
 764                 return ret;
 765         BUG_ON(ret == 0 || path->slots[0] == 0);
 766
 767         path->slots[0]--;
 768         l = path->nodes[0];
 769
 770         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 771         BUG_ON(key.objectid != bytenr);
 772         BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
 773
 774         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 775         refs = btrfs_extent_refs(l, item);
 776         btrfs_set_extent_refs(l, item, refs + 1);
 777         btrfs_mark_buffer_dirty(path->nodes[0]);
 778
 779         btrfs_release_path(root->fs_info->extent_root, path);
 780
 781         path->reada = 1;
 782         ret = insert_extent_backref(trans, root->fs_info->extent_root,
 783                                     path, bytenr, parent,
 784                                     ref_root, ref_generation,
 785                                     owner_objectid);
 786         BUG_ON(ret);
 787         finish_current_insert(trans, root->fs_info->extent_root);
 788         del_pending_extents(trans, root->fs_info->extent_root);
 789
 790         btrfs_free_path(path);
 791         return 0;
 792 }
 793
 794 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 795                          struct btrfs_root *root,
 796                          u64 bytenr, u64 num_bytes, u64 parent,
 797                          u64 ref_root, u64 ref_generation,
 798                          u64 owner_objectid)
 799 {
 800         int ret;
 801         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
 802             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
 803                 return 0;
 804         ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
 805                                      0, ref_root, 0, ref_generation,
 806                                      owner_objectid);
 807         return ret;
 808 }
 809
 810 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
 811                          struct btrfs_root *root)
 812 {
 813         finish_current_insert(trans, root->fs_info->extent_root);
 814         del_pending_extents(trans, root->fs_info->extent_root);
 815         return 0;
 816 }
 817
 818 int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
 819                             struct btrfs_root *root, u64 bytenr,
 820                             u64 num_bytes, u32 *refs)
 821 {
 822         struct btrfs_path *path;
 823         int ret;
 824         struct btrfs_key key;
 825         struct extent_buffer *l;
 826         struct btrfs_extent_item *item;
 827
 828         WARN_ON(num_bytes < root->sectorsize);
 829         path = btrfs_alloc_path();
 830         path->reada = 1;
 831         key.objectid = bytenr;
 832         key.offset = num_bytes;
 833         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 834         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 835                                 0, 0);
 836         if (ret < 0)
 837                 goto out;
 838         if (ret != 0) {
 839                 btrfs_print_leaf(root, path->nodes[0]);
 840                 printk("failed to find block number %Lu\n", bytenr);
 841                 BUG();
 842         }
 843         l = path->nodes[0];
 844         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 845         *refs = btrfs_extent_refs(l, item);
 846 out:
 847         btrfs_free_path(path);
 848         return 0;
 849 }
 850
 851 static int get_reference_status(struct btrfs_root *root, u64 bytenr,
 852                                 u64 parent_gen, u64 ref_objectid,
 853                                 u64 *min_generation, u32 *ref_count)
 854 {
 855         struct btrfs_root *extent_root = root->fs_info->extent_root;
 856         struct btrfs_path *path;
 857         struct extent_buffer *leaf;
 858         struct btrfs_extent_ref *ref_item;
 859         struct btrfs_key key;
 860         struct btrfs_key found_key;
 861         u64 root_objectid = root->root_key.objectid;
 862         u64 ref_generation;
 863         u32 nritems;
 864         int ret;
 865
 866         key.objectid = bytenr;
 867         key.offset = (u64)-1;
 868         key.type = BTRFS_EXTENT_ITEM_KEY;
 869
 870         path = btrfs_alloc_path();
 871         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 872         if (ret < 0)
 873                 goto out;
 874         BUG_ON(ret == 0);
 875         if (ret < 0 || path->slots[0] == 0)
 876                 goto out;
 877
 878         path->slots[0]--;
 879         leaf = path->nodes[0];
 880         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 881
 882         if (found_key.objectid != bytenr ||
 883             found_key.type != BTRFS_EXTENT_ITEM_KEY) {
 884                 ret = 1;
 885                 goto out;
 886         }
 887
 888         *ref_count = 0;
 889         *min_generation = (u64)-1;
 890
 891         while (1) {
 892                 leaf = path->nodes[0];
 893                 nritems = btrfs_header_nritems(leaf);
 894                 if (path->slots[0] >= nritems) {
 895                         ret = btrfs_next_leaf(extent_root, path);
 896                         if (ret < 0)
 897                                 goto out;
 898                         if (ret == 0)
 899                                 continue;
 900                         break;
 901                 }
 902                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 903                 if (found_key.objectid != bytenr)
 904                         break;
 905
 906                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
 907                         path->slots[0]++;
 908                         continue;
 909                 }
 910
 911                 ref_item = btrfs_item_ptr(leaf, path->slots[0],
 912                                           struct btrfs_extent_ref);
 913                 ref_generation = btrfs_ref_generation(leaf, ref_item);
 914                 /*
 915                  * For (parent_gen > 0 && parent_gen > ref_generation):
 916                  *
 917                  * we reach here through the oldest root, therefore
 918                  * all other reference from same snapshot should have
 919                  * a larger generation.
 920                  */
 921                 if ((root_objectid != btrfs_ref_root(leaf, ref_item)) ||
 922                     (parent_gen > 0 && parent_gen > ref_generation) ||
 923                     (ref_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
 924                      ref_objectid != btrfs_ref_objectid(leaf, ref_item))) {
 925                         *ref_count = 2;
 926                         break;
 927                 }
 928
 929                 *ref_count = 1;
 930                 if (*min_generation > ref_generation)
 931                         *min_generation = ref_generation;
 932
 933                 path->slots[0]++;
 934         }
 935         ret = 0;
 936 out:
 937         btrfs_free_path(path);
 938         return ret;
 939 }
 940
 941 int btrfs_cross_ref_exists(struct btrfs_trans_handle *trans,
 942                            struct btrfs_root *root,
 943                            struct btrfs_key *key, u64 bytenr)
 944 {
 945         struct btrfs_root *old_root;
 946         struct btrfs_path *path = NULL;
 947         struct extent_buffer *eb;
 948         struct btrfs_file_extent_item *item;
 949         u64 ref_generation;
 950         u64 min_generation;
 951         u64 extent_start;
 952         u32 ref_count;
 953         int level;
 954         int ret;
 955
 956         BUG_ON(trans == NULL);
 957         BUG_ON(key->type != BTRFS_EXTENT_DATA_KEY);
 958         ret = get_reference_status(root, bytenr, 0, key->objectid,
 959                                    &min_generation, &ref_count);
 960         if (ret)
 961                 return ret;
 962
 963         if (ref_count != 1)
 964                 return 1;
 965
 966         old_root = root->dirty_root->root;
 967         ref_generation = old_root->root_key.offset;
 968
 969         /* all references are created in running transaction */
 970         if (min_generation > ref_generation) {
 971                 ret = 0;
 972                 goto out;
 973         }
 974
 975         path = btrfs_alloc_path();
 976         if (!path) {
 977                 ret = -ENOMEM;
 978                 goto out;
 979         }
 980
 981         path->skip_locking = 1;
 982         /* if no item found, the extent is referenced by other snapshot */
 983         ret = btrfs_search_slot(NULL, old_root, key, path, 0, 0);
 984         if (ret)
 985                 goto out;
 986
 987         eb = path->nodes[0];
 988         item = btrfs_item_ptr(eb, path->slots[0],
 989                               struct btrfs_file_extent_item);
 990         if (btrfs_file_extent_type(eb, item) != BTRFS_FILE_EXTENT_REG ||
 991             btrfs_file_extent_disk_bytenr(eb, item) != bytenr) {
 992                 ret = 1;
 993                 goto out;
 994         }
 995
 996         for (level = BTRFS_MAX_LEVEL - 1; level >= -1; level--) {
 997                 if (level >= 0) {
 998                         eb = path->nodes[level];
 999                         if (!eb)
1000                                 continue;
1001                         extent_start = eb->start;
1002                 } else
1003                         extent_start = bytenr;
1004
1005                 ret = get_reference_status(root, extent_start, ref_generation,
1006                                            0, &min_generation, &ref_count);
1007                 if (ret)
1008                         goto out;
1009
1010                 if (ref_count != 1) {
1011                         ret = 1;
1012                         goto out;
1013                 }
1014                 if (level >= 0)
1015                         ref_generation = btrfs_header_generation(eb);
1016         }
1017         ret = 0;
1018 out:
1019         if (path)
1020                 btrfs_free_path(path);
1021         return ret;
1022 }
1023
1024 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1025                     struct extent_buffer *buf, u32 nr_extents)
1026 {
1027         struct btrfs_key key;
1028         struct btrfs_file_extent_item *fi;
1029         u64 root_gen;
1030         u32 nritems;
1031         int i;
1032         int level;
1033         int ret = 0;
1034         int shared = 0;
1035
1036         if (!root->ref_cows)
1037                 return 0;
1038
1039         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1040                 shared = 0;
1041                 root_gen = root->root_key.offset;
1042         } else {
1043                 shared = 1;
1044                 root_gen = trans->transid - 1;
1045         }
1046
1047         level = btrfs_header_level(buf);
1048         nritems = btrfs_header_nritems(buf);
1049
1050         if (level == 0) {
1051                 struct btrfs_leaf_ref *ref;
1052                 struct btrfs_extent_info *info;
1053
1054                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
1055                 if (!ref) {
1056                         ret = -ENOMEM;
1057                         goto out;
1058                 }
1059
1060                 ref->root_gen = root_gen;
1061                 ref->bytenr = buf->start;
1062                 ref->owner = btrfs_header_owner(buf);
1063                 ref->generation = btrfs_header_generation(buf);
1064                 ref->nritems = nr_extents;
1065                 info = ref->extents;
1066
1067                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
1068                         u64 disk_bytenr;
1069                         btrfs_item_key_to_cpu(buf, &key, i);
1070                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1071                                 continue;
1072                         fi = btrfs_item_ptr(buf, i,
1073                                             struct btrfs_file_extent_item);
1074                         if (btrfs_file_extent_type(buf, fi) ==
1075                             BTRFS_FILE_EXTENT_INLINE)
1076                                 continue;
1077                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1078                         if (disk_bytenr == 0)
1079                                 continue;
1080
1081                         info->bytenr = disk_bytenr;
1082                         info->num_bytes =
1083                                 btrfs_file_extent_disk_num_bytes(buf, fi);
1084                         info->objectid = key.objectid;
1085                         info->offset = key.offset;
1086                         info++;
1087                 }
1088
1089                 ret = btrfs_add_leaf_ref(root, ref, shared);
1090                 if (ret == -EEXIST && shared) {
1091                         struct btrfs_leaf_ref *old;
1092                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
1093                         BUG_ON(!old);
1094                         btrfs_remove_leaf_ref(root, old);
1095                         btrfs_free_leaf_ref(root, old);
1096                         ret = btrfs_add_leaf_ref(root, ref, shared);
1097                 }
1098                 WARN_ON(ret);
1099                 btrfs_free_leaf_ref(root, ref);
1100         }
1101 out:
1102         return ret;
1103 }
1104
1105 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1106                   struct extent_buffer *orig_buf, struct extent_buffer *buf,
1107                   u32 *nr_extents)
1108 {
1109         u64 bytenr;
1110         u64 ref_root;
1111         u64 orig_root;
1112         u64 ref_generation;
1113         u64 orig_generation;
1114         u32 nritems;
1115         u32 nr_file_extents = 0;
1116         struct btrfs_key key;
1117         struct btrfs_file_extent_item *fi;
1118         int i;
1119         int level;
1120         int ret = 0;
1121         int faili = 0;
1122         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
1123                             u64, u64, u64, u64, u64, u64, u64, u64);
1124
1125         ref_root = btrfs_header_owner(buf);
1126         ref_generation = btrfs_header_generation(buf);
1127         orig_root = btrfs_header_owner(orig_buf);
1128         orig_generation = btrfs_header_generation(orig_buf);
1129
1130         nritems = btrfs_header_nritems(buf);
1131         level = btrfs_header_level(buf);
1132
1133         if (root->ref_cows) {
1134                 process_func = __btrfs_inc_extent_ref;
1135         } else {
1136                 if (level == 0 &&
1137                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1138                         goto out;
1139                 if (level != 0 &&
1140                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1141                         goto out;
1142                 process_func = __btrfs_update_extent_ref;
1143         }
1144
1145         for (i = 0; i < nritems; i++) {
1146                 cond_resched();
1147                 if (level == 0) {
1148                         btrfs_item_key_to_cpu(buf, &key, i);
1149                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1150                                 continue;
1151                         fi = btrfs_item_ptr(buf, i,
1152                                             struct btrfs_file_extent_item);
1153                         if (btrfs_file_extent_type(buf, fi) ==
1154                             BTRFS_FILE_EXTENT_INLINE)
1155                                 continue;
1156                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1157                         if (bytenr == 0)
1158                                 continue;
1159
1160                         nr_file_extents++;
1161
1162                         ret = process_func(trans, root, bytenr,
1163                                            orig_buf->start, buf->start,
1164                                            orig_root, ref_root,
1165                                            orig_generation, ref_generation,
1166                                            key.objectid);
1167
1168                         if (ret) {
1169                                 faili = i;
1170                                 WARN_ON(1);
1171                                 goto fail;
1172                         }
1173                 } else {
1174                         bytenr = btrfs_node_blockptr(buf, i);
1175                         ret = process_func(trans, root, bytenr,
1176                                            orig_buf->start, buf->start,
1177                                            orig_root, ref_root,
1178                                            orig_generation, ref_generation,
1179                                            level - 1);
1180                         if (ret) {
1181                                 faili = i;
1182                                 WARN_ON(1);
1183                                 goto fail;
1184                         }
1185                 }
1186         }
1187 out:
1188         if (nr_extents) {
1189                 if (level == 0)
1190                         *nr_extents = nr_file_extents;
1191                 else
1192                         *nr_extents = nritems;
1193         }
1194         return 0;
1195 fail:
1196         WARN_ON(1);
1197         return ret;
1198 }
1199
1200 int btrfs_update_ref(struct btrfs_trans_handle *trans,
1201                      struct btrfs_root *root, struct extent_buffer *orig_buf,
1202                      struct extent_buffer *buf, int start_slot, int nr)
1203
1204 {
1205         u64 bytenr;
1206         u64 ref_root;
1207         u64 orig_root;
1208         u64 ref_generation;
1209         u64 orig_generation;
1210         struct btrfs_key key;
1211         struct btrfs_file_extent_item *fi;
1212         int i;
1213         int ret;
1214         int slot;
1215         int level;
1216
1217         BUG_ON(start_slot < 0);
1218         BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
1219
1220         ref_root = btrfs_header_owner(buf);
1221         ref_generation = btrfs_header_generation(buf);
1222         orig_root = btrfs_header_owner(orig_buf);
1223         orig_generation = btrfs_header_generation(orig_buf);
1224         level = btrfs_header_level(buf);
1225
1226         if (!root->ref_cows) {
1227                 if (level == 0 &&
1228                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1229                         return 0;
1230                 if (level != 0 &&
1231                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1232                         return 0;
1233         }
1234
1235         for (i = 0, slot = start_slot; i < nr; i++, slot++) {
1236                 cond_resched();
1237                 if (level == 0) {
1238                         btrfs_item_key_to_cpu(buf, &key, slot);
1239                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1240                                 continue;
1241                         fi = btrfs_item_ptr(buf, slot,
1242                                             struct btrfs_file_extent_item);
1243                         if (btrfs_file_extent_type(buf, fi) ==
1244                             BTRFS_FILE_EXTENT_INLINE)
1245                                 continue;
1246                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1247                         if (bytenr == 0)
1248                                 continue;
1249                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1250                                             orig_buf->start, buf->start,
1251                                             orig_root, ref_root,
1252                                             orig_generation, ref_generation,
1253                                             key.objectid);
1254                         if (ret)
1255                                 goto fail;
1256                 } else {
1257                         bytenr = btrfs_node_blockptr(buf, slot);
1258                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1259                                             orig_buf->start, buf->start,
1260                                             orig_root, ref_root,
1261                                             orig_generation, ref_generation,
1262                                             level - 1);
1263                         if (ret)
1264                                 goto fail;
1265                 }
1266         }
1267         return 0;
1268 fail:
1269         WARN_ON(1);
1270         return -1;
1271 }
1272
1273 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1274                                  struct btrfs_root *root,
1275                                  struct btrfs_path *path,
1276                                  struct btrfs_block_group_cache *cache)
1277 {
1278         int ret;
1279         int pending_ret;
1280         struct btrfs_root *extent_root = root->fs_info->extent_root;
1281         unsigned long bi;
1282         struct extent_buffer *leaf;
1283
1284         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1285         if (ret < 0)
1286                 goto fail;
1287         BUG_ON(ret);
1288
1289         leaf = path->nodes[0];
1290         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1291         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1292         btrfs_mark_buffer_dirty(leaf);
1293         btrfs_release_path(extent_root, path);
1294 fail:
1295         finish_current_insert(trans, extent_root);
1296         pending_ret = del_pending_extents(trans, extent_root);
1297         if (ret)
1298                 return ret;
1299         if (pending_ret)
1300                 return pending_ret;
1301         return 0;
1302
1303 }
1304
1305 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1306                                    struct btrfs_root *root)
1307 {
1308         struct btrfs_block_group_cache *cache, *entry;
1309         struct rb_node *n;
1310         int err = 0;
1311         int werr = 0;
1312         struct btrfs_path *path;
1313         u64 last = 0;
1314
1315         path = btrfs_alloc_path();
1316         if (!path)
1317                 return -ENOMEM;
1318
1319         while(1) {
1320                 cache = NULL;
1321                 spin_lock(&root->fs_info->block_group_cache_lock);
1322                 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1323                      n; n = rb_next(n)) {
1324                         entry = rb_entry(n, struct btrfs_block_group_cache,
1325                                          cache_node);
1326                         if (entry->dirty) {
1327                                 cache = entry;
1328                                 break;
1329                         }
1330                 }
1331                 spin_unlock(&root->fs_info->block_group_cache_lock);
1332
1333                 if (!cache)
1334                         break;
1335
1336                 cache->dirty = 0;
1337                 last += cache->key.offset;
1338
1339                 err = write_one_cache_group(trans, root,
1340                                             path, cache);
1341                 /*
1342                  * if we fail to write the cache group, we want
1343                  * to keep it marked dirty in hopes that a later
1344                  * write will work
1345                  */
1346                 if (err) {
1347                         werr = err;
1348                         continue;
1349                 }
1350         }
1351         btrfs_free_path(path);
1352         return werr;
1353 }
1354
1355 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1356                              u64 total_bytes, u64 bytes_used,
1357                              struct btrfs_space_info **space_info)
1358 {
1359         struct btrfs_space_info *found;
1360
1361         found = __find_space_info(info, flags);
1362         if (found) {
1363                 spin_lock(&found->lock);
1364                 found->total_bytes += total_bytes;
1365                 found->bytes_used += bytes_used;
1366                 found->full = 0;
1367                 spin_unlock(&found->lock);
1368                 *space_info = found;
1369                 return 0;
1370         }
1371         found = kmalloc(sizeof(*found), GFP_NOFS);
1372         if (!found)
1373                 return -ENOMEM;
1374
1375         list_add(&found->list, &info->space_info);
1376         INIT_LIST_HEAD(&found->block_groups);
1377         init_rwsem(&found->groups_sem);
1378         spin_lock_init(&found->lock);
1379         found->flags = flags;
1380         found->total_bytes = total_bytes;
1381         found->bytes_used = bytes_used;
1382         found->bytes_pinned = 0;
1383         found->bytes_reserved = 0;
1384         found->full = 0;
1385         found->force_alloc = 0;
1386         *space_info = found;
1387         return 0;
1388 }
1389
1390 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1391 {
1392         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1393                                    BTRFS_BLOCK_GROUP_RAID1 |
1394                                    BTRFS_BLOCK_GROUP_RAID10 |
1395                                    BTRFS_BLOCK_GROUP_DUP);
1396         if (extra_flags) {
1397                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1398                         fs_info->avail_data_alloc_bits |= extra_flags;
1399                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1400                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1401                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1402                         fs_info->avail_system_alloc_bits |= extra_flags;
1403         }
1404 }
1405
1406 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1407 {
1408         u64 num_devices = root->fs_info->fs_devices->num_devices;
1409
1410         if (num_devices == 1)
1411                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1412         if (num_devices < 4)
1413                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1414
1415         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1416             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1417                       BTRFS_BLOCK_GROUP_RAID10))) {
1418                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1419         }
1420
1421         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1422             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1423                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1424         }
1425
1426         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1427             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1428              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1429              (flags & BTRFS_BLOCK_GROUP_DUP)))
1430                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1431         return flags;
1432 }
1433
1434 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1435                           struct btrfs_root *extent_root, u64 alloc_bytes,
1436                           u64 flags, int force)
1437 {
1438         struct btrfs_space_info *space_info;
1439         u64 thresh;
1440         u64 start;
1441         u64 num_bytes;
1442         int ret = 0, waited = 0;
1443
1444         flags = reduce_alloc_profile(extent_root, flags);
1445
1446         space_info = __find_space_info(extent_root->fs_info, flags);
1447         if (!space_info) {
1448                 ret = update_space_info(extent_root->fs_info, flags,
1449                                         0, 0, &space_info);
1450                 BUG_ON(ret);
1451         }
1452         BUG_ON(!space_info);
1453
1454         spin_lock(&space_info->lock);
1455         if (space_info->force_alloc) {
1456                 force = 1;
1457                 space_info->force_alloc = 0;
1458         }
1459         if (space_info->full) {
1460                 spin_unlock(&space_info->lock);
1461                 goto out;
1462         }
1463
1464         thresh = div_factor(space_info->total_bytes, 6);
1465         if (!force &&
1466            (space_info->bytes_used + space_info->bytes_pinned +
1467             space_info->bytes_reserved + alloc_bytes) < thresh) {
1468                 spin_unlock(&space_info->lock);
1469                 goto out;
1470         }
1471
1472         spin_unlock(&space_info->lock);
1473
1474         ret = mutex_trylock(&extent_root->fs_info->chunk_mutex);
1475         if (!ret && !force) {
1476                 goto out;
1477         } else if (!ret) {
1478                 mutex_lock(&extent_root->fs_info->chunk_mutex);
1479                 waited = 1;
1480         }
1481
1482         if (waited) {
1483                 spin_lock(&space_info->lock);
1484                 if (space_info->full) {
1485                         spin_unlock(&space_info->lock);
1486                         goto out_unlock;
1487                 }
1488                 spin_unlock(&space_info->lock);
1489         }
1490
1491         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1492         if (ret) {
1493 printk("space info full %Lu\n", flags);
1494                 space_info->full = 1;
1495                 goto out_unlock;
1496         }
1497
1498         ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1499                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1500         BUG_ON(ret);
1501 out_unlock:
1502         mutex_unlock(&extent_root->fs_info->chunk_mutex);
1503 out:
1504         return ret;
1505 }
1506
1507 static int update_block_group(struct btrfs_trans_handle *trans,
1508                               struct btrfs_root *root,
1509                               u64 bytenr, u64 num_bytes, int alloc,
1510                               int mark_free)
1511 {
1512         struct btrfs_block_group_cache *cache;
1513         struct btrfs_fs_info *info = root->fs_info;
1514         u64 total = num_bytes;
1515         u64 old_val;
1516         u64 byte_in_group;
1517
1518         while(total) {
1519                 cache = btrfs_lookup_block_group(info, bytenr);
1520                 if (!cache) {
1521                         return -1;
1522                 }
1523                 byte_in_group = bytenr - cache->key.objectid;
1524                 WARN_ON(byte_in_group > cache->key.offset);
1525
1526                 spin_lock(&cache->space_info->lock);
1527                 spin_lock(&cache->lock);
1528                 cache->dirty = 1;
1529                 old_val = btrfs_block_group_used(&cache->item);
1530                 num_bytes = min(total, cache->key.offset - byte_in_group);
1531                 if (alloc) {
1532                         old_val += num_bytes;
1533                         cache->space_info->bytes_used += num_bytes;
1534                         btrfs_set_block_group_used(&cache->item, old_val);
1535                         spin_unlock(&cache->lock);
1536                         spin_unlock(&cache->space_info->lock);
1537                 } else {
1538                         old_val -= num_bytes;
1539                         cache->space_info->bytes_used -= num_bytes;
1540                         btrfs_set_block_group_used(&cache->item, old_val);
1541                         spin_unlock(&cache->lock);
1542                         spin_unlock(&cache->space_info->lock);
1543                         if (mark_free) {
1544                                 int ret;
1545                                 ret = btrfs_add_free_space(cache, bytenr,
1546                                                            num_bytes);
1547                                 if (ret)
1548                                         return -1;
1549                         }
1550                 }
1551                 total -= num_bytes;
1552                 bytenr += num_bytes;
1553         }
1554         return 0;
1555 }
1556
1557 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
1558 {
1559         struct btrfs_block_group_cache *cache;
1560
1561         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
1562         if (!cache)
1563                 return 0;
1564
1565         return cache->key.objectid;
1566 }
1567
1568 int btrfs_update_pinned_extents(struct btrfs_root *root,
1569                                 u64 bytenr, u64 num, int pin)
1570 {
1571         u64 len;
1572         struct btrfs_block_group_cache *cache;
1573         struct btrfs_fs_info *fs_info = root->fs_info;
1574
1575         WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
1576         if (pin) {
1577                 set_extent_dirty(&fs_info->pinned_extents,
1578                                 bytenr, bytenr + num - 1, GFP_NOFS);
1579         } else {
1580                 clear_extent_dirty(&fs_info->pinned_extents,
1581                                 bytenr, bytenr + num - 1, GFP_NOFS);
1582         }
1583         while (num > 0) {
1584                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1585                 BUG_ON(!cache);
1586                 len = min(num, cache->key.offset -
1587                           (bytenr - cache->key.objectid));
1588                 if (pin) {
1589                         spin_lock(&cache->space_info->lock);
1590                         spin_lock(&cache->lock);
1591                         cache->pinned += len;
1592                         cache->space_info->bytes_pinned += len;
1593                         spin_unlock(&cache->lock);
1594                         spin_unlock(&cache->space_info->lock);
1595                         fs_info->total_pinned += len;
1596                 } else {
1597                         spin_lock(&cache->space_info->lock);
1598                         spin_lock(&cache->lock);
1599                         cache->pinned -= len;
1600                         cache->space_info->bytes_pinned -= len;
1601                         spin_unlock(&cache->lock);
1602                         spin_unlock(&cache->space_info->lock);
1603                         fs_info->total_pinned -= len;
1604                 }
1605                 bytenr += len;
1606                 num -= len;
1607         }
1608         return 0;
1609 }
1610
1611 static int update_reserved_extents(struct btrfs_root *root,
1612                                    u64 bytenr, u64 num, int reserve)
1613 {
1614         u64 len;
1615         struct btrfs_block_group_cache *cache;
1616         struct btrfs_fs_info *fs_info = root->fs_info;
1617
1618         while (num > 0) {
1619                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1620                 BUG_ON(!cache);
1621                 len = min(num, cache->key.offset -
1622                           (bytenr - cache->key.objectid));
1623
1624                 spin_lock(&cache->space_info->lock);
1625                 spin_lock(&cache->lock);
1626                 if (reserve) {
1627                         cache->reserved += len;
1628                         cache->space_info->bytes_reserved += len;
1629                 } else {
1630                         cache->reserved -= len;
1631                         cache->space_info->bytes_reserved -= len;
1632                 }
1633                 spin_unlock(&cache->lock);
1634                 spin_unlock(&cache->space_info->lock);
1635                 bytenr += len;
1636                 num -= len;
1637         }
1638         return 0;
1639 }
1640
1641 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1642 {
1643         u64 last = 0;
1644         u64 start;
1645         u64 end;
1646         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1647         int ret;
1648
1649         mutex_lock(&root->fs_info->pinned_mutex);
1650         while(1) {
1651                 ret = find_first_extent_bit(pinned_extents, last,
1652                                             &start, &end, EXTENT_DIRTY);
1653                 if (ret)
1654                         break;
1655                 set_extent_dirty(copy, start, end, GFP_NOFS);
1656                 last = end + 1;
1657         }
1658         mutex_unlock(&root->fs_info->pinned_mutex);
1659         return 0;
1660 }
1661
1662 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1663                                struct btrfs_root *root,
1664                                struct extent_io_tree *unpin)
1665 {
1666         u64 start;
1667         u64 end;
1668         int ret;
1669         struct btrfs_block_group_cache *cache;
1670
1671         mutex_lock(&root->fs_info->pinned_mutex);
1672         while(1) {
1673                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1674                                             EXTENT_DIRTY);
1675                 if (ret)
1676                         break;
1677                 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
1678                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1679                 cache = btrfs_lookup_block_group(root->fs_info, start);
1680                 if (cache->cached)
1681                         btrfs_add_free_space(cache, start, end - start + 1);
1682                 if (need_resched()) {
1683                         mutex_unlock(&root->fs_info->pinned_mutex);
1684                         cond_resched();
1685                         mutex_lock(&root->fs_info->pinned_mutex);
1686                 }
1687         }
1688         mutex_unlock(&root->fs_info->pinned_mutex);
1689         return 0;
1690 }
1691
1692 static int finish_current_insert(struct btrfs_trans_handle *trans,
1693                                  struct btrfs_root *extent_root)
1694 {
1695         u64 start;
1696         u64 end;
1697         u64 priv;
1698         u64 search = 0;
1699         struct btrfs_fs_info *info = extent_root->fs_info;
1700         struct btrfs_path *path;
1701         struct btrfs_extent_ref *ref;
1702         struct pending_extent_op *extent_op;
1703         struct btrfs_key key;
1704         struct btrfs_extent_item extent_item;
1705         int ret;
1706         int err = 0;
1707
1708         btrfs_set_stack_extent_refs(&extent_item, 1);
1709         path = btrfs_alloc_path();
1710
1711         while(1) {
1712                 mutex_lock(&info->extent_ins_mutex);
1713                 ret = find_first_extent_bit(&info->extent_ins, search, &start,
1714                                             &end, EXTENT_WRITEBACK);
1715                 if (ret) {
1716                         mutex_unlock(&info->extent_ins_mutex);
1717                         if (search) {
1718                                 search = 0;
1719                                 continue;
1720                         }
1721                         break;
1722                 }
1723
1724                 ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
1725                 if (!ret) {
1726                         search = end+1;
1727                         mutex_unlock(&info->extent_ins_mutex);
1728                         cond_resched();
1729                         continue;
1730                 }
1731                 BUG_ON(ret < 0);
1732
1733                 ret = get_state_private(&info->extent_ins, start, &priv);
1734                 BUG_ON(ret);
1735                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1736
1737                 mutex_unlock(&info->extent_ins_mutex);
1738
1739                 if (extent_op->type == PENDING_EXTENT_INSERT) {
1740                         key.objectid = start;
1741                         key.offset = end + 1 - start;
1742                         key.type = BTRFS_EXTENT_ITEM_KEY;
1743                         err = btrfs_insert_item(trans, extent_root, &key,
1744                                         &extent_item, sizeof(extent_item));
1745                         BUG_ON(err);
1746
1747                         mutex_lock(&info->extent_ins_mutex);
1748                         clear_extent_bits(&info->extent_ins, start, end,
1749                                           EXTENT_WRITEBACK, GFP_NOFS);
1750                         mutex_unlock(&info->extent_ins_mutex);
1751
1752                         err = insert_extent_backref(trans, extent_root, path,
1753                                                 start, extent_op->parent,
1754                                                 extent_root->root_key.objectid,
1755                                                 extent_op->generation,
1756                                                 extent_op->level);
1757                         BUG_ON(err);
1758                 } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
1759                         err = lookup_extent_backref(trans, extent_root, path,
1760                                                 start, extent_op->orig_parent,
1761                                                 extent_root->root_key.objectid,
1762                                                 extent_op->orig_generation,
1763                                                 extent_op->level, 0);
1764                         BUG_ON(err);
1765
1766                         mutex_lock(&info->extent_ins_mutex);
1767                         clear_extent_bits(&info->extent_ins, start, end,
1768                                           EXTENT_WRITEBACK, GFP_NOFS);
1769                         mutex_unlock(&info->extent_ins_mutex);
1770
1771                         key.objectid = start;
1772                         key.offset = extent_op->parent;
1773                         key.type = BTRFS_EXTENT_REF_KEY;
1774                         err = btrfs_set_item_key_safe(trans, extent_root, path,
1775                                                       &key);
1776                         BUG_ON(err);
1777                         ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1778                                              struct btrfs_extent_ref);
1779                         btrfs_set_ref_generation(path->nodes[0], ref,
1780                                                  extent_op->generation);
1781                         btrfs_mark_buffer_dirty(path->nodes[0]);
1782                         btrfs_release_path(extent_root, path);
1783                 } else {
1784                         BUG_ON(1);
1785                 }
1786                 kfree(extent_op);
1787                 unlock_extent(&info->extent_ins, start, end, GFP_NOFS);
1788                 search = 0;
1789
1790                 cond_resched();
1791         }
1792         btrfs_free_path(path);
1793         return 0;
1794 }
1795
1796 static int pin_down_bytes(struct btrfs_trans_handle *trans,
1797                           struct btrfs_root *root,
1798                           u64 bytenr, u64 num_bytes, int is_data)
1799 {
1800         int err = 0;
1801         struct extent_buffer *buf;
1802
1803         if (is_data)
1804                 goto pinit;
1805
1806         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1807         if (!buf)
1808                 goto pinit;
1809
1810         /* we can reuse a block if it hasn't been written
1811          * and it is from this transaction.  We can't
1812          * reuse anything from the tree log root because
1813          * it has tiny sub-transactions.
1814          */
1815         if (btrfs_buffer_uptodate(buf, 0) &&
1816             btrfs_try_tree_lock(buf)) {
1817                 u64 header_owner = btrfs_header_owner(buf);
1818                 u64 header_transid = btrfs_header_generation(buf);
1819                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
1820                     header_owner != BTRFS_TREE_RELOC_OBJECTID &&
1821                     header_transid == trans->transid &&
1822                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
1823                         clean_tree_block(NULL, root, buf);
1824                         btrfs_tree_unlock(buf);
1825                         free_extent_buffer(buf);
1826                         return 1;
1827                 }
1828                 btrfs_tree_unlock(buf);
1829         }
1830         free_extent_buffer(buf);
1831 pinit:
1832         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
1833
1834         BUG_ON(err < 0);
1835         return 0;
1836 }
1837
1838 /*
1839  * remove an extent from the root, returns 0 on success
1840  */
1841 static int __free_extent(struct btrfs_trans_handle *trans,
1842                          struct btrfs_root *root,
1843                          u64 bytenr, u64 num_bytes, u64 parent,
1844                          u64 root_objectid, u64 ref_generation,
1845                          u64 owner_objectid, int pin, int mark_free)
1846 {
1847         struct btrfs_path *path;
1848         struct btrfs_key key;
1849         struct btrfs_fs_info *info = root->fs_info;
1850         struct btrfs_root *extent_root = info->extent_root;
1851         struct extent_buffer *leaf;
1852         int ret;
1853         int extent_slot = 0;
1854         int found_extent = 0;
1855         int num_to_del = 1;
1856         struct btrfs_extent_item *ei;
1857         u32 refs;
1858
1859         key.objectid = bytenr;
1860         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1861         key.offset = num_bytes;
1862         path = btrfs_alloc_path();
1863         if (!path)
1864                 return -ENOMEM;
1865
1866         path->reada = 1;
1867         ret = lookup_extent_backref(trans, extent_root, path,
1868                                     bytenr, parent, root_objectid,
1869                                     ref_generation, owner_objectid, 1);
1870         if (ret == 0) {
1871                 struct btrfs_key found_key;
1872                 extent_slot = path->slots[0];
1873                 while(extent_slot > 0) {
1874                         extent_slot--;
1875                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1876                                               extent_slot);
1877                         if (found_key.objectid != bytenr)
1878                                 break;
1879                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1880                             found_key.offset == num_bytes) {
1881                                 found_extent = 1;
1882                                 break;
1883                         }
1884                         if (path->slots[0] - extent_slot > 5)
1885                                 break;
1886                 }
1887                 if (!found_extent) {
1888                         ret = remove_extent_backref(trans, extent_root, path);
1889                         BUG_ON(ret);
1890                         btrfs_release_path(extent_root, path);
1891                         ret = btrfs_search_slot(trans, extent_root,
1892                                                 &key, path, -1, 1);
1893                         BUG_ON(ret);
1894                         extent_slot = path->slots[0];
1895                 }
1896         } else {
1897                 btrfs_print_leaf(extent_root, path->nodes[0]);
1898                 WARN_ON(1);
1899                 printk("Unable to find ref byte nr %Lu root %Lu "
1900                        "gen %Lu owner %Lu\n", bytenr,
1901                        root_objectid, ref_generation, owner_objectid);
1902         }
1903
1904         leaf = path->nodes[0];
1905         ei = btrfs_item_ptr(leaf, extent_slot,
1906                             struct btrfs_extent_item);
1907         refs = btrfs_extent_refs(leaf, ei);
1908         BUG_ON(refs == 0);
1909         refs -= 1;
1910         btrfs_set_extent_refs(leaf, ei, refs);
1911
1912         btrfs_mark_buffer_dirty(leaf);
1913
1914         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1915                 struct btrfs_extent_ref *ref;
1916                 ref = btrfs_item_ptr(leaf, path->slots[0],
1917                                      struct btrfs_extent_ref);
1918                 BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
1919                 /* if the back ref and the extent are next to each other
1920                  * they get deleted below in one shot
1921                  */
1922                 path->slots[0] = extent_slot;
1923                 num_to_del = 2;
1924         } else if (found_extent) {
1925                 /* otherwise delete the extent back ref */
1926                 ret = remove_extent_backref(trans, extent_root, path);
1927                 BUG_ON(ret);
1928                 /* if refs are 0, we need to setup the path for deletion */
1929                 if (refs == 0) {
1930                         btrfs_release_path(extent_root, path);
1931                         ret = btrfs_search_slot(trans, extent_root, &key, path,
1932                                                 -1, 1);
1933                         BUG_ON(ret);
1934                 }
1935         }
1936
1937         if (refs == 0) {
1938                 u64 super_used;
1939                 u64 root_used;
1940 #ifdef BIO_RW_DISCARD
1941                 u64 map_length = num_bytes;
1942                 struct btrfs_multi_bio *multi = NULL;
1943 #endif
1944
1945                 if (pin) {
1946                         mutex_lock(&root->fs_info->pinned_mutex);
1947                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
1948                                 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID);
1949                         mutex_unlock(&root->fs_info->pinned_mutex);
1950                         if (ret > 0)
1951                                 mark_free = 1;
1952                         BUG_ON(ret < 0);
1953                 }
1954
1955                 /* block accounting for super block */
1956                 spin_lock_irq(&info->delalloc_lock);
1957                 super_used = btrfs_super_bytes_used(&info->super_copy);
1958                 btrfs_set_super_bytes_used(&info->super_copy,
1959                                            super_used - num_bytes);
1960                 spin_unlock_irq(&info->delalloc_lock);
1961
1962                 /* block accounting for root item */
1963                 root_used = btrfs_root_used(&root->root_item);
1964                 btrfs_set_root_used(&root->root_item,
1965                                            root_used - num_bytes);
1966                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1967                                       num_to_del);
1968                 BUG_ON(ret);
1969                 btrfs_release_path(extent_root, path);
1970                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1971                                          mark_free);
1972                 BUG_ON(ret);
1973
1974 #ifdef BIO_RW_DISCARD
1975                 /* Tell the block device(s) that the sectors can be discarded */
1976                 ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1977                                       bytenr, &map_length, &multi, 0);
1978                 if (!ret) {
1979                         struct btrfs_bio_stripe *stripe = multi->stripes;
1980                         int i;
1981
1982                         if (map_length > num_bytes)
1983                                 map_length = num_bytes;
1984
1985                         for (i = 0; i < multi->num_stripes; i++, stripe++) {
1986                                 blkdev_issue_discard(stripe->dev->bdev,
1987                                                      stripe->physical >> 9,
1988                                                      map_length >> 9);
1989                         }
1990                         kfree(multi);
1991                 }
1992 #endif
1993         }
1994         btrfs_free_path(path);
1995         finish_current_insert(trans, extent_root);
1996         return ret;
1997 }
1998
1999 /*
2000  * find all the blocks marked as pending in the radix tree and remove
2001  * them from the extent map
2002  */
2003 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
2004                                btrfs_root *extent_root)
2005 {
2006         int ret;
2007         int err = 0;
2008         u64 start;
2009         u64 end;
2010         u64 priv;
2011         u64 search = 0;
2012         struct extent_io_tree *pending_del;
2013         struct extent_io_tree *extent_ins;
2014         struct pending_extent_op *extent_op;
2015         struct btrfs_fs_info *info = extent_root->fs_info;
2016
2017         extent_ins = &extent_root->fs_info->extent_ins;
2018         pending_del = &extent_root->fs_info->pending_del;
2019
2020         while(1) {
2021                 mutex_lock(&info->extent_ins_mutex);
2022                 ret = find_first_extent_bit(pending_del, search, &start, &end,
2023                                             EXTENT_WRITEBACK);
2024                 if (ret) {
2025                         mutex_unlock(&info->extent_ins_mutex);
2026                         if (search) {
2027                                 search = 0;
2028                                 continue;
2029                         }
2030                         break;
2031                 }
2032
2033                 ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
2034                 if (!ret) {
2035                         search = end+1;
2036                         mutex_unlock(&info->extent_ins_mutex);
2037                         cond_resched();
2038                         continue;
2039                 }
2040                 BUG_ON(ret < 0);
2041
2042                 ret = get_state_private(pending_del, start, &priv);
2043                 BUG_ON(ret);
2044                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2045
2046                 clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
2047                                   GFP_NOFS);
2048                 if (!test_range_bit(extent_ins, start, end,
2049                                     EXTENT_WRITEBACK, 0)) {
2050                         mutex_unlock(&info->extent_ins_mutex);
2051 free_extent:
2052                         ret = __free_extent(trans, extent_root,
2053                                             start, end + 1 - start,
2054                                             extent_op->orig_parent,
2055                                             extent_root->root_key.objectid,
2056                                             extent_op->orig_generation,
2057                                             extent_op->level, 1, 0);
2058                         kfree(extent_op);
2059                 } else {
2060                         kfree(extent_op);
2061
2062                         ret = get_state_private(&info->extent_ins, start,
2063                                                 &priv);
2064                         BUG_ON(ret);
2065                         extent_op = (struct pending_extent_op *)
2066                                                 (unsigned long)priv;
2067
2068                         clear_extent_bits(&info->extent_ins, start, end,
2069                                           EXTENT_WRITEBACK, GFP_NOFS);
2070
2071                         mutex_unlock(&info->extent_ins_mutex);
2072
2073                         if (extent_op->type == PENDING_BACKREF_UPDATE)
2074                                 goto free_extent;
2075
2076                         mutex_lock(&extent_root->fs_info->pinned_mutex);
2077                         ret = pin_down_bytes(trans, extent_root, start,
2078                                              end + 1 - start, 0);
2079                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
2080
2081                         ret = update_block_group(trans, extent_root, start,
2082                                                 end + 1 - start, 0, ret > 0);
2083
2084                         BUG_ON(ret);
2085                         kfree(extent_op);
2086                 }
2087                 if (ret)
2088                         err = ret;
2089                 unlock_extent(extent_ins, start, end, GFP_NOFS);
2090
2091                 search = 0;
2092                 cond_resched();
2093         }
2094         return err;
2095 }
2096
2097 /*
2098  * remove an extent from the root, returns 0 on success
2099  */
2100 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2101                                struct btrfs_root *root,
2102                                u64 bytenr, u64 num_bytes, u64 parent,
2103                                u64 root_objectid, u64 ref_generation,
2104                                u64 owner_objectid, int pin)
2105 {
2106         struct btrfs_root *extent_root = root->fs_info->extent_root;
2107         int pending_ret;
2108         int ret;
2109
2110         WARN_ON(num_bytes < root->sectorsize);
2111         if (root == extent_root) {
2112                 struct pending_extent_op *extent_op;
2113
2114                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2115                 BUG_ON(!extent_op);
2116
2117                 extent_op->type = PENDING_EXTENT_DELETE;
2118                 extent_op->bytenr = bytenr;
2119                 extent_op->num_bytes = num_bytes;
2120                 extent_op->parent = parent;
2121                 extent_op->orig_parent = parent;
2122                 extent_op->generation = ref_generation;
2123                 extent_op->orig_generation = ref_generation;
2124                 extent_op->level = (int)owner_objectid;
2125
2126                 mutex_lock(&root->fs_info->extent_ins_mutex);
2127                 set_extent_bits(&root->fs_info->pending_del,
2128                                 bytenr, bytenr + num_bytes - 1,
2129                                 EXTENT_WRITEBACK, GFP_NOFS);
2130                 set_state_private(&root->fs_info->pending_del,
2131                                   bytenr, (unsigned long)extent_op);
2132                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2133                 return 0;
2134         }
2135         /* if metadata always pin */
2136         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2137                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2138                         struct btrfs_block_group_cache *cache;
2139
2140                         /* btrfs_free_reserved_extent */
2141                         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
2142                         BUG_ON(!cache);
2143                         btrfs_add_free_space(cache, bytenr, num_bytes);
2144                         update_reserved_extents(root, bytenr, num_bytes, 0);
2145                         return 0;
2146                 }
2147                 pin = 1;
2148         }
2149
2150         /* if data pin when any transaction has committed this */
2151         if (ref_generation != trans->transid)
2152                 pin = 1;
2153
2154         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2155                             root_objectid, ref_generation,
2156                             owner_objectid, pin, pin == 0);
2157
2158         finish_current_insert(trans, root->fs_info->extent_root);
2159         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
2160         return ret ? ret : pending_ret;
2161 }
2162
2163 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2164                       struct btrfs_root *root,
2165                       u64 bytenr, u64 num_bytes, u64 parent,
2166                       u64 root_objectid, u64 ref_generation,
2167                       u64 owner_objectid, int pin)
2168 {
2169         int ret;
2170
2171         ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
2172                                   root_objectid, ref_generation,
2173                                   owner_objectid, pin);
2174         return ret;
2175 }
2176
2177 static u64 stripe_align(struct btrfs_root *root, u64 val)
2178 {
2179         u64 mask = ((u64)root->stripesize - 1);
2180         u64 ret = (val + mask) & ~mask;
2181         return ret;
2182 }
2183
2184 /*
2185  * walks the btree of allocated extents and find a hole of a given size.
2186  * The key ins is changed to record the hole:
2187  * ins->objectid == block start
2188  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2189  * ins->offset == number of blocks
2190  * Any available blocks before search_start are skipped.
2191  */
2192 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
2193                                      struct btrfs_root *orig_root,
2194                                      u64 num_bytes, u64 empty_size,
2195                                      u64 search_start, u64 search_end,
2196                                      u64 hint_byte, struct btrfs_key *ins,
2197                                      u64 exclude_start, u64 exclude_nr,
2198                                      int data)
2199 {
2200         int ret = 0;
2201         struct btrfs_root * root = orig_root->fs_info->extent_root;
2202         u64 total_needed = num_bytes;
2203         u64 *last_ptr = NULL;
2204         struct btrfs_block_group_cache *block_group = NULL;
2205         int chunk_alloc_done = 0;
2206         int empty_cluster = 2 * 1024 * 1024;
2207         int allowed_chunk_alloc = 0;
2208         struct list_head *head = NULL, *cur = NULL;
2209         int loop = 0;
2210         struct btrfs_space_info *space_info;
2211
2212         WARN_ON(num_bytes < root->sectorsize);
2213         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2214         ins->objectid = 0;
2215         ins->offset = 0;
2216
2217         if (orig_root->ref_cows || empty_size)
2218                 allowed_chunk_alloc = 1;
2219
2220         if (data & BTRFS_BLOCK_GROUP_METADATA) {
2221                 last_ptr = &root->fs_info->last_alloc;
2222                 empty_cluster = 256 * 1024;
2223         }
2224
2225         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
2226                 last_ptr = &root->fs_info->last_data_alloc;
2227
2228         if (last_ptr) {
2229                 if (*last_ptr)
2230                         hint_byte = *last_ptr;
2231                 else
2232                         empty_size += empty_cluster;
2233         }
2234         search_start = max(search_start, first_logical_byte(root, 0));
2235         search_start = max(search_start, hint_byte);
2236         total_needed += empty_size;
2237
2238         block_group = btrfs_lookup_block_group(root->fs_info, search_start);
2239         space_info = __find_space_info(root->fs_info, data);
2240
2241         down_read(&space_info->groups_sem);
2242         while (1) {
2243                 struct btrfs_free_space *free_space;
2244                 /*
2245                  * the only way this happens if our hint points to a block
2246                  * group thats not of the proper type, while looping this
2247                  * should never happen
2248                  */
2249                 WARN_ON(!block_group);
2250                 mutex_lock(&block_group->alloc_mutex);
2251                 if (unlikely(!block_group_bits(block_group, data)))
2252                         goto new_group;
2253
2254                 ret = cache_block_group(root, block_group);
2255                 if (ret) {
2256                         mutex_unlock(&block_group->alloc_mutex);
2257                         break;
2258                 }
2259
2260                 if (block_group->ro)
2261                         goto new_group;
2262
2263                 free_space = btrfs_find_free_space(block_group, search_start,
2264                                                    total_needed);
2265                 if (free_space) {
2266                         u64 start = block_group->key.objectid;
2267                         u64 end = block_group->key.objectid +
2268                                 block_group->key.offset;
2269
2270                         search_start = stripe_align(root, free_space->offset);
2271
2272                         /* move on to the next group */
2273                         if (search_start + num_bytes >= search_end)
2274                                 goto new_group;
2275
2276                         /* move on to the next group */
2277                         if (search_start + num_bytes > end)
2278                                 goto new_group;
2279
2280                         if (exclude_nr > 0 &&
2281                             (search_start + num_bytes > exclude_start &&
2282                              search_start < exclude_start + exclude_nr)) {
2283                                 search_start = exclude_start + exclude_nr;
2284                                 /*
2285                                  * if search_start is still in this block group
2286                                  * then we just re-search this block group
2287                                  */
2288                                 if (search_start >= start &&
2289                                     search_start < end) {
2290                                         mutex_unlock(&block_group->alloc_mutex);
2291                                         continue;
2292                                 }
2293
2294                                 /* else we go to the next block group */
2295                                 goto new_group;
2296                         }
2297
2298                         ins->objectid = search_start;
2299                         ins->offset = num_bytes;
2300
2301                         btrfs_remove_free_space_lock(block_group, search_start,
2302                                                      num_bytes);
2303                         /* we are all good, lets return */
2304                         mutex_unlock(&block_group->alloc_mutex);
2305                         break;
2306                 }
2307 new_group:
2308                 mutex_unlock(&block_group->alloc_mutex);
2309                 /*
2310                  * Here's how this works.
2311                  * loop == 0: we were searching a block group via a hint
2312                  *              and didn't find anything, so we start at
2313                  *              the head of the block groups and keep searching
2314                  * loop == 1: we're searching through all of the block groups
2315                  *              if we hit the head again we have searched
2316                  *              all of the block groups for this space and we
2317                  *              need to try and allocate, if we cant error out.
2318                  * loop == 2: we allocated more space and are looping through
2319                  *              all of the block groups again.
2320                  */
2321                 if (loop == 0) {
2322                         head = &space_info->block_groups;
2323                         cur = head->next;
2324
2325                         if (last_ptr && *last_ptr) {
2326                                 total_needed += empty_cluster;
2327                                 *last_ptr = 0;
2328                         }
2329                         loop++;
2330                 } else if (loop == 1 && cur == head) {
2331                         if (allowed_chunk_alloc && !chunk_alloc_done) {
2332                                 up_read(&space_info->groups_sem);
2333                                 ret = do_chunk_alloc(trans, root, num_bytes +
2334                                                      2 * 1024 * 1024, data, 1);
2335                                 if (ret < 0)
2336                                         break;
2337                                 down_read(&space_info->groups_sem);
2338                                 loop++;
2339                                 head = &space_info->block_groups;
2340                                 cur = head->next;
2341                                 chunk_alloc_done = 1;
2342                         } else if (!allowed_chunk_alloc) {
2343                                 space_info->force_alloc = 1;
2344                                 break;
2345                         } else {
2346                                 break;
2347                         }
2348                 } else if (cur == head) {
2349                         break;
2350                 }
2351
2352                 block_group = list_entry(cur, struct btrfs_block_group_cache,
2353                                          list);
2354                 search_start = block_group->key.objectid;
2355                 cur = cur->next;
2356         }
2357
2358         /* we found what we needed */
2359         if (ins->objectid) {
2360                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
2361                         trans->block_group = block_group;
2362
2363                 if (last_ptr)
2364                         *last_ptr = ins->objectid + ins->offset;
2365                 ret = 0;
2366         } else if (!ret) {
2367                 ret = -ENOSPC;
2368         }
2369
2370         up_read(&space_info->groups_sem);
2371         return ret;
2372 }
2373
2374 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
2375 {
2376         struct btrfs_block_group_cache *cache;
2377         struct list_head *l;
2378
2379         printk(KERN_INFO "space_info has %Lu free, is %sfull\n",
2380                info->total_bytes - info->bytes_used - info->bytes_pinned -
2381                info->bytes_reserved, (info->full) ? "" : "not ");
2382
2383         down_read(&info->groups_sem);
2384         list_for_each(l, &info->block_groups) {
2385                 cache = list_entry(l, struct btrfs_block_group_cache, list);
2386                 spin_lock(&cache->lock);
2387                 printk(KERN_INFO "block group %Lu has %Lu bytes, %Lu used "
2388                        "%Lu pinned %Lu reserved\n",
2389                        cache->key.objectid, cache->key.offset,
2390                        btrfs_block_group_used(&cache->item),
2391                        cache->pinned, cache->reserved);
2392                 btrfs_dump_free_space(cache, bytes);
2393                 spin_unlock(&cache->lock);
2394         }
2395         up_read(&info->groups_sem);
2396 }
2397
2398 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2399                                   struct btrfs_root *root,
2400                                   u64 num_bytes, u64 min_alloc_size,
2401                                   u64 empty_size, u64 hint_byte,
2402                                   u64 search_end, struct btrfs_key *ins,
2403                                   u64 data)
2404 {
2405         int ret;
2406         u64 search_start = 0;
2407         u64 alloc_profile;
2408         struct btrfs_fs_info *info = root->fs_info;
2409
2410         if (data) {
2411                 alloc_profile = info->avail_data_alloc_bits &
2412                                 info->data_alloc_profile;
2413                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2414         } else if (root == root->fs_info->chunk_root) {
2415                 alloc_profile = info->avail_system_alloc_bits &
2416                                 info->system_alloc_profile;
2417                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2418         } else {
2419                 alloc_profile = info->avail_metadata_alloc_bits &
2420                                 info->metadata_alloc_profile;
2421                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2422         }
2423 again:
2424         data = reduce_alloc_profile(root, data);
2425         /*
2426          * the only place that sets empty_size is btrfs_realloc_node, which
2427          * is not called recursively on allocations
2428          */
2429         if (empty_size || root->ref_cows) {
2430                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2431                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2432                                      2 * 1024 * 1024,
2433                                      BTRFS_BLOCK_GROUP_METADATA |
2434                                      (info->metadata_alloc_profile &
2435                                       info->avail_metadata_alloc_bits), 0);
2436                 }
2437                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2438                                      num_bytes + 2 * 1024 * 1024, data, 0);
2439         }
2440
2441         WARN_ON(num_bytes < root->sectorsize);
2442         ret = find_free_extent(trans, root, num_bytes, empty_size,
2443                                search_start, search_end, hint_byte, ins,
2444                                trans->alloc_exclude_start,
2445                                trans->alloc_exclude_nr, data);
2446
2447         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
2448                 num_bytes = num_bytes >> 1;
2449                 num_bytes = num_bytes & ~(root->sectorsize - 1);
2450                 num_bytes = max(num_bytes, min_alloc_size);
2451                 do_chunk_alloc(trans, root->fs_info->extent_root,
2452                                num_bytes, data, 1);
2453                 goto again;
2454         }
2455         if (ret) {
2456                 struct btrfs_space_info *sinfo;
2457
2458                 sinfo = __find_space_info(root->fs_info, data);
2459                 printk("allocation failed flags %Lu, wanted %Lu\n",
2460                        data, num_bytes);
2461                 dump_space_info(sinfo, num_bytes);
2462                 BUG();
2463         }
2464
2465         return ret;
2466 }
2467
2468 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
2469 {
2470         struct btrfs_block_group_cache *cache;
2471
2472         cache = btrfs_lookup_block_group(root->fs_info, start);
2473         if (!cache) {
2474                 printk(KERN_ERR "Unable to find block group for %Lu\n", start);
2475                 return -ENOSPC;
2476         }
2477         btrfs_add_free_space(cache, start, len);
2478         update_reserved_extents(root, start, len, 0);
2479         return 0;
2480 }
2481
2482 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2483                                   struct btrfs_root *root,
2484                                   u64 num_bytes, u64 min_alloc_size,
2485                                   u64 empty_size, u64 hint_byte,
2486                                   u64 search_end, struct btrfs_key *ins,
2487                                   u64 data)
2488 {
2489         int ret;
2490         ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
2491                                      empty_size, hint_byte, search_end, ins,
2492                                      data);
2493         update_reserved_extents(root, ins->objectid, ins->offset, 1);
2494         return ret;
2495 }
2496
2497 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2498                                          struct btrfs_root *root, u64 parent,
2499                                          u64 root_objectid, u64 ref_generation,
2500                                          u64 owner, struct btrfs_key *ins)
2501 {
2502         int ret;
2503         int pending_ret;
2504         u64 super_used;
2505         u64 root_used;
2506         u64 num_bytes = ins->offset;
2507         u32 sizes[2];
2508         struct btrfs_fs_info *info = root->fs_info;
2509         struct btrfs_root *extent_root = info->extent_root;
2510         struct btrfs_extent_item *extent_item;
2511         struct btrfs_extent_ref *ref;
2512         struct btrfs_path *path;
2513         struct btrfs_key keys[2];
2514
2515         if (parent == 0)
2516                 parent = ins->objectid;
2517
2518         /* block accounting for super block */
2519         spin_lock_irq(&info->delalloc_lock);
2520         super_used = btrfs_super_bytes_used(&info->super_copy);
2521         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
2522         spin_unlock_irq(&info->delalloc_lock);
2523
2524         /* block accounting for root item */
2525         root_used = btrfs_root_used(&root->root_item);
2526         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
2527
2528         if (root == extent_root) {
2529                 struct pending_extent_op *extent_op;
2530
2531                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2532                 BUG_ON(!extent_op);
2533
2534                 extent_op->type = PENDING_EXTENT_INSERT;
2535                 extent_op->bytenr = ins->objectid;
2536                 extent_op->num_bytes = ins->offset;
2537                 extent_op->parent = parent;
2538                 extent_op->orig_parent = 0;
2539                 extent_op->generation = ref_generation;
2540                 extent_op->orig_generation = 0;
2541                 extent_op->level = (int)owner;
2542
2543                 mutex_lock(&root->fs_info->extent_ins_mutex);
2544                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2545                                 ins->objectid + ins->offset - 1,
2546                                 EXTENT_WRITEBACK, GFP_NOFS);
2547                 set_state_private(&root->fs_info->extent_ins,
2548                                   ins->objectid, (unsigned long)extent_op);
2549                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2550                 goto update_block;
2551         }
2552
2553         memcpy(&keys[0], ins, sizeof(*ins));
2554         keys[1].objectid = ins->objectid;
2555         keys[1].type = BTRFS_EXTENT_REF_KEY;
2556         keys[1].offset = parent;
2557         sizes[0] = sizeof(*extent_item);
2558         sizes[1] = sizeof(*ref);
2559
2560         path = btrfs_alloc_path();
2561         BUG_ON(!path);
2562
2563         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
2564                                        sizes, 2);
2565         BUG_ON(ret);
2566
2567         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2568                                      struct btrfs_extent_item);
2569         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
2570         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
2571                              struct btrfs_extent_ref);
2572
2573         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
2574         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
2575         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
2576         btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
2577
2578         btrfs_mark_buffer_dirty(path->nodes[0]);
2579
2580         trans->alloc_exclude_start = 0;
2581         trans->alloc_exclude_nr = 0;
2582         btrfs_free_path(path);
2583         finish_current_insert(trans, extent_root);
2584         pending_ret = del_pending_extents(trans, extent_root);
2585
2586         if (ret)
2587                 goto out;
2588         if (pending_ret) {
2589                 ret = pending_ret;
2590                 goto out;
2591         }
2592
2593 update_block:
2594         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
2595         if (ret) {
2596                 printk("update block group failed for %Lu %Lu\n",
2597                        ins->objectid, ins->offset);
2598                 BUG();
2599         }
2600 out:
2601         return ret;
2602 }
2603
2604 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
2605                                 struct btrfs_root *root, u64 parent,
2606                                 u64 root_objectid, u64 ref_generation,
2607                                 u64 owner, struct btrfs_key *ins)
2608 {
2609         int ret;
2610
2611         if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
2612                 return 0;
2613         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
2614                                             ref_generation, owner, ins);
2615         update_reserved_extents(root, ins->objectid, ins->offset, 0);
2616         return ret;
2617 }
2618
2619 /*
2620  * this is used by the tree logging recovery code.  It records that
2621  * an extent has been allocated and makes sure to clear the free
2622  * space cache bits as well
2623  */
2624 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
2625                                 struct btrfs_root *root, u64 parent,
2626                                 u64 root_objectid, u64 ref_generation,
2627                                 u64 owner, struct btrfs_key *ins)
2628 {
2629         int ret;
2630         struct btrfs_block_group_cache *block_group;
2631
2632         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
2633         mutex_lock(&block_group->alloc_mutex);
2634         cache_block_group(root, block_group);
2635
2636         ret = btrfs_remove_free_space_lock(block_group, ins->objectid,
2637                                            ins->offset);
2638         mutex_unlock(&block_group->alloc_mutex);
2639         BUG_ON(ret);
2640         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
2641                                             ref_generation, owner, ins);
2642         return ret;
2643 }
2644
2645 /*
2646  * finds a free extent and does all the dirty work required for allocation
2647  * returns the key for the extent through ins, and a tree buffer for
2648  * the first block of the extent through buf.
2649  *
2650  * returns 0 if everything worked, non-zero otherwise.
2651  */
2652 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
2653                        struct btrfs_root *root,
2654                        u64 num_bytes, u64 parent, u64 min_alloc_size,
2655                        u64 root_objectid, u64 ref_generation,
2656                        u64 owner_objectid, u64 empty_size, u64 hint_byte,
2657                        u64 search_end, struct btrfs_key *ins, u64 data)
2658 {
2659         int ret;
2660
2661         ret = __btrfs_reserve_extent(trans, root, num_bytes,
2662                                      min_alloc_size, empty_size, hint_byte,
2663                                      search_end, ins, data);
2664         BUG_ON(ret);
2665         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
2666                 ret = __btrfs_alloc_reserved_extent(trans, root, parent,
2667                                         root_objectid, ref_generation,
2668                                         owner_objectid, ins);
2669                 BUG_ON(ret);
2670
2671         } else {
2672                 update_reserved_extents(root, ins->objectid, ins->offset, 1);
2673         }
2674         return ret;
2675 }
2676
2677 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
2678                                             struct btrfs_root *root,
2679                                             u64 bytenr, u32 blocksize)
2680 {
2681         struct extent_buffer *buf;
2682
2683         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
2684         if (!buf)
2685                 return ERR_PTR(-ENOMEM);
2686         btrfs_set_header_generation(buf, trans->transid);
2687         btrfs_tree_lock(buf);
2688         clean_tree_block(trans, root, buf);
2689         btrfs_set_buffer_uptodate(buf);
2690         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2691                 set_extent_dirty(&root->dirty_log_pages, buf->start,
2692                          buf->start + buf->len - 1, GFP_NOFS);
2693         } else {
2694                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
2695                          buf->start + buf->len - 1, GFP_NOFS);
2696         }
2697         trans->blocks_used++;
2698         return buf;
2699 }
2700
2701 /*
2702  * helper function to allocate a block for a given tree
2703  * returns the tree buffer or NULL.
2704  */
2705 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2706                                              struct btrfs_root *root,
2707                                              u32 blocksize, u64 parent,
2708                                              u64 root_objectid,
2709                                              u64 ref_generation,
2710                                              int level,
2711                                              u64 hint,
2712                                              u64 empty_size)
2713 {
2714         struct btrfs_key ins;
2715         int ret;
2716         struct extent_buffer *buf;
2717
2718         ret = btrfs_alloc_extent(trans, root, blocksize, parent, blocksize,
2719                                  root_objectid, ref_generation, level,
2720                                  empty_size, hint, (u64)-1, &ins, 0);
2721         if (ret) {
2722                 BUG_ON(ret > 0);
2723                 return ERR_PTR(ret);
2724         }
2725
2726         buf = btrfs_init_new_buffer(trans, root, ins.objectid, blocksize);
2727         return buf;
2728 }
2729
2730 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
2731                         struct btrfs_root *root, struct extent_buffer *leaf)
2732 {
2733         u64 leaf_owner;
2734         u64 leaf_generation;
2735         struct btrfs_key key;
2736         struct btrfs_file_extent_item *fi;
2737         int i;
2738         int nritems;
2739         int ret;
2740
2741         BUG_ON(!btrfs_is_leaf(leaf));
2742         nritems = btrfs_header_nritems(leaf);
2743         leaf_owner = btrfs_header_owner(leaf);
2744         leaf_generation = btrfs_header_generation(leaf);
2745
2746         for (i = 0; i < nritems; i++) {
2747                 u64 disk_bytenr;
2748                 cond_resched();
2749
2750                 btrfs_item_key_to_cpu(leaf, &key, i);
2751                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2752                         continue;
2753                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2754                 if (btrfs_file_extent_type(leaf, fi) ==
2755                     BTRFS_FILE_EXTENT_INLINE)
2756                         continue;
2757                 /*
2758                  * FIXME make sure to insert a trans record that
2759                  * repeats the snapshot del on crash
2760                  */
2761                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2762                 if (disk_bytenr == 0)
2763                         continue;
2764
2765                 ret = __btrfs_free_extent(trans, root, disk_bytenr,
2766                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2767                                 leaf->start, leaf_owner, leaf_generation,
2768                                 key.objectid, 0);
2769                 BUG_ON(ret);
2770
2771                 atomic_inc(&root->fs_info->throttle_gen);
2772                 wake_up(&root->fs_info->transaction_throttle);
2773                 cond_resched();
2774         }
2775         return 0;
2776 }
2777
2778 static int noinline cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
2779                                         struct btrfs_root *root,
2780                                         struct btrfs_leaf_ref *ref)
2781 {
2782         int i;
2783         int ret;
2784         struct btrfs_extent_info *info = ref->extents;
2785
2786         for (i = 0; i < ref->nritems; i++) {
2787                 ret = __btrfs_free_extent(trans, root, info->bytenr,
2788                                           info->num_bytes, ref->bytenr,
2789                                           ref->owner, ref->generation,
2790                                           info->objectid, 0);
2791
2792                 atomic_inc(&root->fs_info->throttle_gen);
2793                 wake_up(&root->fs_info->transaction_throttle);
2794                 cond_resched();
2795
2796                 BUG_ON(ret);
2797                 info++;
2798         }
2799
2800         return 0;
2801 }
2802
2803 int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
2804                               u32 *refs)
2805 {
2806         int ret;
2807
2808         ret = btrfs_lookup_extent_ref(NULL, root, start, len, refs);
2809         BUG_ON(ret);
2810
2811 #if 0 // some debugging code in case we see problems here
2812         /* if the refs count is one, it won't get increased again.  But
2813          * if the ref count is > 1, someone may be decreasing it at
2814          * the same time we are.
2815          */
2816         if (*refs != 1) {
2817                 struct extent_buffer *eb = NULL;
2818                 eb = btrfs_find_create_tree_block(root, start, len);
2819                 if (eb)
2820                         btrfs_tree_lock(eb);
2821
2822                 mutex_lock(&root->fs_info->alloc_mutex);
2823                 ret = lookup_extent_ref(NULL, root, start, len, refs);
2824                 BUG_ON(ret);
2825                 mutex_unlock(&root->fs_info->alloc_mutex);
2826
2827                 if (eb) {
2828                         btrfs_tree_unlock(eb);
2829                         free_extent_buffer(eb);
2830                 }
2831                 if (*refs == 1) {
2832                         printk("block %llu went down to one during drop_snap\n",
2833                                (unsigned long long)start);
2834                 }
2835
2836         }
2837 #endif
2838
2839         cond_resched();
2840         return ret;
2841 }
2842
2843 /*
2844  * helper function for drop_snapshot, this walks down the tree dropping ref
2845  * counts as it goes.
2846  */
2847 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2848                                    struct btrfs_root *root,
2849                                    struct btrfs_path *path, int *level)
2850 {
2851         u64 root_owner;
2852         u64 root_gen;
2853         u64 bytenr;
2854         u64 ptr_gen;
2855         struct extent_buffer *next;
2856         struct extent_buffer *cur;
2857         struct extent_buffer *parent;
2858         struct btrfs_leaf_ref *ref;
2859         u32 blocksize;
2860         int ret;
2861         u32 refs;
2862
2863         WARN_ON(*level < 0);
2864         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2865         ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
2866                                 path->nodes[*level]->len, &refs);
2867         BUG_ON(ret);
2868         if (refs > 1)
2869                 goto out;
2870
2871         /*
2872          * walk down to the last node level and free all the leaves
2873          */
2874         while(*level >= 0) {
2875                 WARN_ON(*level < 0);
2876                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2877                 cur = path->nodes[*level];
2878
2879                 if (btrfs_header_level(cur) != *level)
2880                         WARN_ON(1);
2881
2882                 if (path->slots[*level] >=
2883                     btrfs_header_nritems(cur))
2884                         break;
2885                 if (*level == 0) {
2886                         ret = btrfs_drop_leaf_ref(trans, root, cur);
2887                         BUG_ON(ret);
2888                         break;
2889                 }
2890                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2891                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2892                 blocksize = btrfs_level_size(root, *level - 1);
2893
2894                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
2895                 BUG_ON(ret);
2896                 if (refs != 1) {
2897                         parent = path->nodes[*level];
2898                         root_owner = btrfs_header_owner(parent);
2899                         root_gen = btrfs_header_generation(parent);
2900                         path->slots[*level]++;
2901
2902                         ret = __btrfs_free_extent(trans, root, bytenr,
2903                                                 blocksize, parent->start,
2904                                                 root_owner, root_gen,
2905                                                 *level - 1, 1);
2906                         BUG_ON(ret);
2907
2908                         atomic_inc(&root->fs_info->throttle_gen);
2909                         wake_up(&root->fs_info->transaction_throttle);
2910                         cond_resched();
2911
2912                         continue;
2913                 }
2914                 /*
2915                  * at this point, we have a single ref, and since the
2916                  * only place referencing this extent is a dead root
2917                  * the reference count should never go higher.
2918                  * So, we don't need to check it again
2919                  */
2920                 if (*level == 1) {
2921                         ref = btrfs_lookup_leaf_ref(root, bytenr);
2922                         if (ref && ref->generation != ptr_gen) {
2923                                 btrfs_free_leaf_ref(root, ref);
2924                                 ref = NULL;
2925                         }
2926                         if (ref) {
2927                                 ret = cache_drop_leaf_ref(trans, root, ref);
2928                                 BUG_ON(ret);
2929                                 btrfs_remove_leaf_ref(root, ref);
2930                                 btrfs_free_leaf_ref(root, ref);
2931                                 *level = 0;
2932                                 break;
2933                         }
2934                         if (printk_ratelimit()) {
2935                                 printk("leaf ref miss for bytenr %llu\n",
2936                                        (unsigned long long)bytenr);
2937                         }
2938                 }
2939                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2940                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2941                         free_extent_buffer(next);
2942
2943                         next = read_tree_block(root, bytenr, blocksize,
2944                                                ptr_gen);
2945                         cond_resched();
2946 #if 0
2947                         /*
2948                          * this is a debugging check and can go away
2949                          * the ref should never go all the way down to 1
2950                          * at this point
2951                          */
2952                         ret = lookup_extent_ref(NULL, root, bytenr, blocksize,
2953                                                 &refs);
2954                         BUG_ON(ret);
2955                         WARN_ON(refs != 1);
2956 #endif
2957                 }
2958                 WARN_ON(*level <= 0);
2959                 if (path->nodes[*level-1])
2960                         free_extent_buffer(path->nodes[*level-1]);
2961                 path->nodes[*level-1] = next;
2962                 *level = btrfs_header_level(next);
2963                 path->slots[*level] = 0;
2964                 cond_resched();
2965         }
2966 out:
2967         WARN_ON(*level < 0);
2968         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2969
2970         if (path->nodes[*level] == root->node) {
2971                 parent = path->nodes[*level];
2972                 bytenr = path->nodes[*level]->start;
2973         } else {
2974                 parent = path->nodes[*level + 1];
2975                 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
2976         }
2977
2978         blocksize = btrfs_level_size(root, *level);
2979         root_owner = btrfs_header_owner(parent);
2980         root_gen = btrfs_header_generation(parent);
2981
2982         ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
2983                                   parent->start, root_owner, root_gen,
2984                                   *level, 1);
2985         free_extent_buffer(path->nodes[*level]);
2986         path->nodes[*level] = NULL;
2987         *level += 1;
2988         BUG_ON(ret);
2989
2990         cond_resched();
2991         return 0;
2992 }
2993
2994 /*
2995  * helper function for drop_subtree, this function is similar to
2996  * walk_down_tree. The main difference is that it checks reference
2997  * counts while tree blocks are locked.
2998  */
2999 static int noinline walk_down_subtree(struct btrfs_trans_handle *trans,
3000                                       struct btrfs_root *root,
3001                                       struct btrfs_path *path, int *level)
3002 {
3003         struct extent_buffer *next;
3004         struct extent_buffer *cur;
3005         struct extent_buffer *parent;
3006         u64 bytenr;
3007         u64 ptr_gen;
3008         u32 blocksize;
3009         u32 refs;
3010         int ret;
3011
3012         cur = path->nodes[*level];
3013         ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
3014                                       &refs);
3015         BUG_ON(ret);
3016         if (refs > 1)
3017                 goto out;
3018
3019         while (*level >= 0) {
3020                 cur = path->nodes[*level];
3021                 if (*level == 0) {
3022                         ret = btrfs_drop_leaf_ref(trans, root, cur);
3023                         BUG_ON(ret);
3024                         clean_tree_block(trans, root, cur);
3025                         break;
3026                 }
3027                 if (path->slots[*level] >= btrfs_header_nritems(cur)) {
3028                         clean_tree_block(trans, root, cur);
3029                         break;
3030                 }
3031
3032                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
3033                 blocksize = btrfs_level_size(root, *level - 1);
3034                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
3035
3036                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
3037                 btrfs_tree_lock(next);
3038
3039                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
3040                                               &refs);
3041                 BUG_ON(ret);
3042                 if (refs > 1) {
3043                         parent = path->nodes[*level];
3044                         ret = btrfs_free_extent(trans, root, bytenr,
3045                                         blocksize, parent->start,
3046                                         btrfs_header_owner(parent),
3047                                         btrfs_header_generation(parent),
3048                                         *level - 1, 1);
3049                         BUG_ON(ret);
3050                         path->slots[*level]++;
3051                         btrfs_tree_unlock(next);
3052                         free_extent_buffer(next);
3053                         continue;
3054                 }
3055
3056                 *level = btrfs_header_level(next);
3057                 path->nodes[*level] = next;
3058                 path->slots[*level] = 0;
3059                 path->locks[*level] = 1;
3060                 cond_resched();
3061         }
3062 out:
3063         parent = path->nodes[*level + 1];
3064         bytenr = path->nodes[*level]->start;
3065         blocksize = path->nodes[*level]->len;
3066
3067         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
3068                         parent->start, btrfs_header_owner(parent),
3069                         btrfs_header_generation(parent), *level, 1);
3070         BUG_ON(ret);
3071
3072         if (path->locks[*level]) {
3073                 btrfs_tree_unlock(path->nodes[*level]);
3074                 path->locks[*level] = 0;
3075         }
3076         free_extent_buffer(path->nodes[*level]);
3077         path->nodes[*level] = NULL;
3078         *level += 1;
3079         cond_resched();
3080         return 0;
3081 }
3082
3083 /*
3084  * helper for dropping snapshots.  This walks back up the tree in the path
3085  * to find the first node higher up where we haven't yet gone through
3086  * all the slots
3087  */
3088 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
3089                                  struct btrfs_root *root,
3090                                  struct btrfs_path *path,
3091                                  int *level, int max_level)
3092 {
3093         u64 root_owner;
3094         u64 root_gen;
3095         struct btrfs_root_item *root_item = &root->root_item;
3096         int i;
3097         int slot;
3098         int ret;
3099
3100         for (i = *level; i < max_level && path->nodes[i]; i++) {
3101                 slot = path->slots[i];
3102                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
3103                         struct extent_buffer *node;
3104                         struct btrfs_disk_key disk_key;
3105                         node = path->nodes[i];
3106                         path->slots[i]++;
3107                         *level = i;
3108                         WARN_ON(*level == 0);
3109                         btrfs_node_key(node, &disk_key, path->slots[i]);
3110                         memcpy(&root_item->drop_progress,
3111                                &disk_key, sizeof(disk_key));
3112                         root_item->drop_level = i;
3113                         return 0;
3114                 } else {
3115                         struct extent_buffer *parent;
3116                         if (path->nodes[*level] == root->node)
3117                                 parent = path->nodes[*level];
3118                         else
3119                                 parent = path->nodes[*level + 1];
3120
3121                         root_owner = btrfs_header_owner(parent);
3122                         root_gen = btrfs_header_generation(parent);
3123
3124                         clean_tree_block(trans, root, path->nodes[*level]);
3125                         ret = btrfs_free_extent(trans, root,
3126                                                 path->nodes[*level]->start,
3127                                                 path->nodes[*level]->len,
3128                                                 parent->start, root_owner,
3129                                                 root_gen, *level, 1);
3130                         BUG_ON(ret);
3131                         if (path->locks[*level]) {
3132                                 btrfs_tree_unlock(path->nodes[*level]);
3133                                 path->locks[*level] = 0;
3134                         }
3135                         free_extent_buffer(path->nodes[*level]);
3136                         path->nodes[*level] = NULL;
3137                         *level = i + 1;
3138                 }
3139         }
3140         return 1;
3141 }
3142
3143 /*
3144  * drop the reference count on the tree rooted at 'snap'.  This traverses
3145  * the tree freeing any blocks that have a ref count of zero after being
3146  * decremented.
3147  */
3148 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
3149                         *root)
3150 {
3151         int ret = 0;
3152         int wret;
3153         int level;
3154         struct btrfs_path *path;
3155         int i;
3156         int orig_level;
3157         struct btrfs_root_item *root_item = &root->root_item;
3158
3159         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
3160         path = btrfs_alloc_path();
3161         BUG_ON(!path);
3162
3163         level = btrfs_header_level(root->node);
3164         orig_level = level;
3165         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
3166                 path->nodes[level] = root->node;
3167                 extent_buffer_get(root->node);
3168                 path->slots[level] = 0;
3169         } else {
3170                 struct btrfs_key key;
3171                 struct btrfs_disk_key found_key;
3172                 struct extent_buffer *node;
3173
3174                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
3175                 level = root_item->drop_level;
3176                 path->lowest_level = level;
3177                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3178                 if (wret < 0) {
3179                         ret = wret;
3180                         goto out;
3181                 }
3182                 node = path->nodes[level];
3183                 btrfs_node_key(node, &found_key, path->slots[level]);
3184                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
3185                                sizeof(found_key)));
3186                 /*
3187                  * unlock our path, this is safe because only this
3188                  * function is allowed to delete this snapshot
3189                  */
3190                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3191                         if (path->nodes[i] && path->locks[i]) {
3192                                 path->locks[i] = 0;
3193                                 btrfs_tree_unlock(path->nodes[i]);
3194                         }
3195                 }
3196         }
3197         while(1) {
3198                 wret = walk_down_tree(trans, root, path, &level);
3199                 if (wret > 0)
3200                         break;
3201                 if (wret < 0)
3202                         ret = wret;
3203
3204                 wret = walk_up_tree(trans, root, path, &level,
3205                                     BTRFS_MAX_LEVEL);
3206                 if (wret > 0)
3207                         break;
3208                 if (wret < 0)
3209                         ret = wret;
3210                 if (trans->transaction->in_commit) {
3211                         ret = -EAGAIN;
3212                         break;
3213                 }
3214                 atomic_inc(&root->fs_info->throttle_gen);
3215                 wake_up(&root->fs_info->transaction_throttle);
3216         }
3217         for (i = 0; i <= orig_level; i++) {
3218                 if (path->nodes[i]) {
3219                         free_extent_buffer(path->nodes[i]);
3220                         path->nodes[i] = NULL;
3221                 }
3222         }
3223 out:
3224         btrfs_free_path(path);
3225         return ret;
3226 }
3227
3228 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
3229                         struct btrfs_root *root,
3230                         struct extent_buffer *node,
3231                         struct extent_buffer *parent)
3232 {
3233         struct btrfs_path *path;
3234         int level;
3235         int parent_level;
3236         int ret = 0;
3237         int wret;
3238
3239         path = btrfs_alloc_path();
3240         BUG_ON(!path);
3241
3242         BUG_ON(!btrfs_tree_locked(parent));
3243         parent_level = btrfs_header_level(parent);
3244         extent_buffer_get(parent);
3245         path->nodes[parent_level] = parent;
3246         path->slots[parent_level] = btrfs_header_nritems(parent);
3247
3248         BUG_ON(!btrfs_tree_locked(node));
3249         level = btrfs_header_level(node);
3250         extent_buffer_get(node);
3251         path->nodes[level] = node;
3252         path->slots[level] = 0;
3253
3254         while (1) {
3255                 wret = walk_down_subtree(trans, root, path, &level);
3256                 if (wret < 0)
3257                         ret = wret;
3258                 if (wret != 0)
3259                         break;
3260
3261                 wret = walk_up_tree(trans, root, path, &level, parent_level);
3262                 if (wret < 0)
3263                         ret = wret;
3264                 if (wret != 0)
3265                         break;
3266         }
3267
3268         btrfs_free_path(path);
3269         return ret;
3270 }
3271
3272 static unsigned long calc_ra(unsigned long start, unsigned long last,
3273                              unsigned long nr)
3274 {
3275         return min(last, start + nr - 1);
3276 }
3277
3278 static int noinline relocate_inode_pages(struct inode *inode, u64 start,
3279                                          u64 len)
3280 {
3281         u64 page_start;
3282         u64 page_end;
3283         unsigned long first_index;
3284         unsigned long last_index;
3285         unsigned long i;
3286         struct page *page;
3287         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3288         struct file_ra_state *ra;
3289         struct btrfs_ordered_extent *ordered;
3290         unsigned int total_read = 0;
3291         unsigned int total_dirty = 0;
3292         int ret = 0;
3293
3294         ra = kzalloc(sizeof(*ra), GFP_NOFS);
3295
3296         mutex_lock(&inode->i_mutex);
3297         first_index = start >> PAGE_CACHE_SHIFT;
3298         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
3299
3300         /* make sure the dirty trick played by the caller work */
3301         ret = invalidate_inode_pages2_range(inode->i_mapping,
3302                                             first_index, last_index);
3303         if (ret)
3304                 goto out_unlock;
3305
3306         file_ra_state_init(ra, inode->i_mapping);
3307
3308         for (i = first_index ; i <= last_index; i++) {
3309                 if (total_read % ra->ra_pages == 0) {
3310                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
3311                                        calc_ra(i, last_index, ra->ra_pages));
3312                 }
3313                 total_read++;
3314 again:
3315                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
3316                         BUG_ON(1);
3317                 page = grab_cache_page(inode->i_mapping, i);
3318                 if (!page) {
3319                         ret = -ENOMEM;
3320                         goto out_unlock;
3321                 }
3322                 if (!PageUptodate(page)) {
3323                         btrfs_readpage(NULL, page);
3324                         lock_page(page);
3325                         if (!PageUptodate(page)) {
3326                                 unlock_page(page);
3327                                 page_cache_release(page);
3328                                 ret = -EIO;
3329                                 goto out_unlock;
3330                         }
3331                 }
3332                 wait_on_page_writeback(page);
3333
3334                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
3335                 page_end = page_start + PAGE_CACHE_SIZE - 1;
3336                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3337
3338                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
3339                 if (ordered) {
3340                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3341                         unlock_page(page);
3342                         page_cache_release(page);
3343                         btrfs_start_ordered_extent(inode, ordered, 1);
3344                         btrfs_put_ordered_extent(ordered);
3345                         goto again;
3346                 }
3347                 set_page_extent_mapped(page);
3348
3349                 btrfs_set_extent_delalloc(inode, page_start, page_end);
3350                 if (i == first_index)
3351                         set_extent_bits(io_tree, page_start, page_end,
3352                                         EXTENT_BOUNDARY, GFP_NOFS);
3353
3354                 set_page_dirty(page);
3355                 total_dirty++;
3356
3357                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3358                 unlock_page(page);
3359                 page_cache_release(page);
3360         }
3361
3362 out_unlock:
3363         kfree(ra);
3364         mutex_unlock(&inode->i_mutex);
3365         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
3366         return ret;
3367 }
3368
3369 static int noinline relocate_data_extent(struct inode *reloc_inode,
3370                                          struct btrfs_key *extent_key,
3371                                          u64 offset)
3372 {
3373         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
3374         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
3375         struct extent_map *em;
3376
3377         em = alloc_extent_map(GFP_NOFS);
3378         BUG_ON(!em || IS_ERR(em));
3379
3380         em->start = extent_key->objectid - offset;
3381         em->len = extent_key->offset;
3382         em->block_len = extent_key->offset;
3383         em->block_start = extent_key->objectid;
3384         em->bdev = root->fs_info->fs_devices->latest_bdev;
3385         set_bit(EXTENT_FLAG_PINNED, &em->flags);
3386
3387         /* setup extent map to cheat btrfs_readpage */
3388         mutex_lock(&BTRFS_I(reloc_inode)->extent_mutex);
3389         while (1) {
3390                 int ret;
3391                 spin_lock(&em_tree->lock);
3392                 ret = add_extent_mapping(em_tree, em);
3393                 spin_unlock(&em_tree->lock);
3394                 if (ret != -EEXIST) {
3395                         free_extent_map(em);
3396                         break;
3397                 }
3398                 btrfs_drop_extent_cache(reloc_inode, em->start,
3399                                         em->start + em->len - 1, 0);
3400         }
3401         mutex_unlock(&BTRFS_I(reloc_inode)->extent_mutex);
3402
3403         return relocate_inode_pages(reloc_inode, extent_key->objectid - offset,
3404                                     extent_key->offset);
3405 }
3406
3407 struct btrfs_ref_path {
3408         u64 extent_start;
3409         u64 nodes[BTRFS_MAX_LEVEL];
3410         u64 root_objectid;
3411         u64 root_generation;
3412         u64 owner_objectid;
3413         u32 num_refs;
3414         int lowest_level;
3415         int current_level;
3416         int shared_level;
3417
3418         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
3419         u64 new_nodes[BTRFS_MAX_LEVEL];
3420 };
3421
3422 struct disk_extent {
3423         u64 ram_bytes;
3424         u64 disk_bytenr;
3425         u64 disk_num_bytes;
3426         u64 offset;
3427         u64 num_bytes;
3428         u8 compression;
3429         u8 encryption;
3430         u16 other_encoding;
3431 };
3432
3433 static int is_cowonly_root(u64 root_objectid)
3434 {
3435         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
3436             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
3437             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
3438             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
3439             root_objectid == BTRFS_TREE_LOG_OBJECTID)
3440                 return 1;
3441         return 0;
3442 }
3443
3444 static int noinline __next_ref_path(struct btrfs_trans_handle *trans,
3445                                     struct btrfs_root *extent_root,
3446                                     struct btrfs_ref_path *ref_path,
3447                                     int first_time)
3448 {
3449         struct extent_buffer *leaf;
3450         struct btrfs_path *path;
3451         struct btrfs_extent_ref *ref;
3452         struct btrfs_key key;
3453         struct btrfs_key found_key;
3454         u64 bytenr;
3455         u32 nritems;
3456         int level;
3457         int ret = 1;
3458
3459         path = btrfs_alloc_path();
3460         if (!path)
3461                 return -ENOMEM;
3462
3463         if (first_time) {
3464                 ref_path->lowest_level = -1;
3465                 ref_path->current_level = -1;
3466                 ref_path->shared_level = -1;
3467                 goto walk_up;
3468         }
3469 walk_down:
3470         level = ref_path->current_level - 1;
3471         while (level >= -1) {
3472                 u64 parent;
3473                 if (level < ref_path->lowest_level)
3474                         break;
3475
3476                 if (level >= 0) {
3477                         bytenr = ref_path->nodes[level];
3478                 } else {
3479                         bytenr = ref_path->extent_start;
3480                 }
3481                 BUG_ON(bytenr == 0);
3482
3483                 parent = ref_path->nodes[level + 1];
3484                 ref_path->nodes[level + 1] = 0;
3485                 ref_path->current_level = level;
3486                 BUG_ON(parent == 0);
3487
3488                 key.objectid = bytenr;
3489                 key.offset = parent + 1;
3490                 key.type = BTRFS_EXTENT_REF_KEY;
3491
3492                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
3493                 if (ret < 0)
3494                         goto out;
3495                 BUG_ON(ret == 0);
3496
3497                 leaf = path->nodes[0];
3498                 nritems = btrfs_header_nritems(leaf);
3499                 if (path->slots[0] >= nritems) {
3500                         ret = btrfs_next_leaf(extent_root, path);
3501                         if (ret < 0)
3502                                 goto out;
3503                         if (ret > 0)
3504                                 goto next;
3505                         leaf = path->nodes[0];
3506                 }
3507
3508                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3509                 if (found_key.objectid == bytenr &&
3510                     found_key.type == BTRFS_EXTENT_REF_KEY) {
3511                         if (level < ref_path->shared_level)
3512                                 ref_path->shared_level = level;
3513                         goto found;
3514                 }
3515 next:
3516                 level--;
3517                 btrfs_release_path(extent_root, path);
3518                 if (need_resched()) {
3519                         cond_resched();
3520                 }
3521         }
3522         /* reached lowest level */
3523         ret = 1;
3524         goto out;
3525 walk_up:
3526         level = ref_path->current_level;
3527         while (level < BTRFS_MAX_LEVEL - 1) {
3528                 u64 ref_objectid;
3529                 if (level >= 0) {
3530                         bytenr = ref_path->nodes[level];
3531                 } else {
3532                         bytenr = ref_path->extent_start;
3533                 }
3534                 BUG_ON(bytenr == 0);
3535
3536                 key.objectid = bytenr;
3537                 key.offset = 0;
3538                 key.type = BTRFS_EXTENT_REF_KEY;
3539
3540                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
3541                 if (ret < 0)
3542                         goto out;
3543
3544                 leaf = path->nodes[0];
3545                 nritems = btrfs_header_nritems(leaf);
3546                 if (path->slots[0] >= nritems) {
3547                         ret = btrfs_next_leaf(extent_root, path);
3548                         if (ret < 0)
3549                                 goto out;
3550                         if (ret > 0) {
3551                                 /* the extent was freed by someone */
3552                                 if (ref_path->lowest_level == level)
3553                                         goto out;
3554                                 btrfs_release_path(extent_root, path);
3555                                 goto walk_down;
3556                         }
3557                         leaf = path->nodes[0];
3558                 }
3559
3560                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3561                 if (found_key.objectid != bytenr ||
3562                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
3563                         /* the extent was freed by someone */
3564                         if (ref_path->lowest_level == level) {
3565                                 ret = 1;
3566                                 goto out;
3567                         }
3568                         btrfs_release_path(extent_root, path);
3569                         goto walk_down;
3570                 }
3571 found:
3572                 ref = btrfs_item_ptr(leaf, path->slots[0],
3573                                 struct btrfs_extent_ref);
3574                 ref_objectid = btrfs_ref_objectid(leaf, ref);
3575                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
3576                         if (first_time) {
3577                                 level = (int)ref_objectid;
3578                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
3579                                 ref_path->lowest_level = level;
3580                                 ref_path->current_level = level;
3581                                 ref_path->nodes[level] = bytenr;
3582                         } else {
3583                                 WARN_ON(ref_objectid != level);
3584                         }
3585                 } else {
3586                         WARN_ON(level != -1);
3587                 }
3588                 first_time = 0;
3589
3590                 if (ref_path->lowest_level == level) {
3591                         ref_path->owner_objectid = ref_objectid;
3592                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
3593                 }
3594
3595                 /*
3596                  * the block is tree root or the block isn't in reference
3597                  * counted tree.
3598                  */
3599                 if (found_key.objectid == found_key.offset ||
3600                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
3601                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
3602                         ref_path->root_generation =
3603                                 btrfs_ref_generation(leaf, ref);
3604                         if (level < 0) {
3605                                 /* special reference from the tree log */
3606                                 ref_path->nodes[0] = found_key.offset;
3607                                 ref_path->current_level = 0;
3608                         }
3609                         ret = 0;
3610                         goto out;
3611                 }
3612
3613                 level++;
3614                 BUG_ON(ref_path->nodes[level] != 0);
3615                 ref_path->nodes[level] = found_key.offset;
3616                 ref_path->current_level = level;
3617
3618                 /*
3619                  * the reference was created in the running transaction,
3620                  * no need to continue walking up.
3621                  */
3622                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
3623                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
3624                         ref_path->root_generation =
3625                                 btrfs_ref_generation(leaf, ref);
3626                         ret = 0;
3627                         goto out;
3628                 }
3629
3630                 btrfs_release_path(extent_root, path);
3631                 if (need_resched()) {
3632                         cond_resched();
3633                 }
3634         }
3635         /* reached max tree level, but no tree root found. */
3636         BUG();
3637 out:
3638         btrfs_free_path(path);
3639         return ret;
3640 }
3641
3642 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
3643                                 struct btrfs_root *extent_root,
3644                                 struct btrfs_ref_path *ref_path,
3645                                 u64 extent_start)
3646 {
3647         memset(ref_path, 0, sizeof(*ref_path));
3648         ref_path->extent_start = extent_start;
3649
3650         return __next_ref_path(trans, extent_root, ref_path, 1);
3651 }
3652
3653 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
3654                                struct btrfs_root *extent_root,
3655                                struct btrfs_ref_path *ref_path)
3656 {
3657         return __next_ref_path(trans, extent_root, ref_path, 0);
3658 }
3659
3660 static int noinline get_new_locations(struct inode *reloc_inode,
3661                                       struct btrfs_key *extent_key,
3662                                       u64 offset, int no_fragment,
3663                                       struct disk_extent **extents,
3664                                       int *nr_extents)
3665 {
3666         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
3667         struct btrfs_path *path;
3668         struct btrfs_file_extent_item *fi;
3669         struct extent_buffer *leaf;
3670         struct disk_extent *exts = *extents;
3671         struct btrfs_key found_key;
3672         u64 cur_pos;
3673         u64 last_byte;
3674         u32 nritems;
3675         int nr = 0;
3676         int max = *nr_extents;
3677         int ret;
3678
3679         WARN_ON(!no_fragment && *extents);
3680         if (!exts) {
3681                 max = 1;
3682                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
3683                 if (!exts)
3684                         return -ENOMEM;
3685         }
3686
3687         path = btrfs_alloc_path();
3688         BUG_ON(!path);
3689
3690         cur_pos = extent_key->objectid - offset;
3691         last_byte = extent_key->objectid + extent_key->offset;
3692         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
3693                                        cur_pos, 0);
3694         if (ret < 0)
3695                 goto out;
3696         if (ret > 0) {
3697                 ret = -ENOENT;
3698                 goto out;
3699         }
3700
3701         while (1) {
3702                 leaf = path->nodes[0];
3703                 nritems = btrfs_header_nritems(leaf);
3704                 if (path->slots[0] >= nritems) {
3705                         ret = btrfs_next_leaf(root, path);
3706                         if (ret < 0)
3707                                 goto out;
3708                         if (ret > 0)
3709                                 break;
3710                         leaf = path->nodes[0];
3711                 }
3712
3713                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3714                 if (found_key.offset != cur_pos ||
3715                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
3716                     found_key.objectid != reloc_inode->i_ino)
3717                         break;
3718
3719                 fi = btrfs_item_ptr(leaf, path->slots[0],
3720                                     struct btrfs_file_extent_item);
3721                 if (btrfs_file_extent_type(leaf, fi) !=
3722                     BTRFS_FILE_EXTENT_REG ||
3723                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
3724                         break;
3725
3726                 if (nr == max) {
3727                         struct disk_extent *old = exts;
3728                         max *= 2;
3729                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
3730                         memcpy(exts, old, sizeof(*exts) * nr);
3731                         if (old != *extents)
3732                                 kfree(old);
3733                 }
3734
3735                 exts[nr].disk_bytenr =
3736                         btrfs_file_extent_disk_bytenr(leaf, fi);
3737                 exts[nr].disk_num_bytes =
3738                         btrfs_file_extent_disk_num_bytes(leaf, fi);
3739                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
3740                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
3741                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
3742                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
3743                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
3744                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
3745                                                                            fi);
3746                 WARN_ON(exts[nr].offset > 0);
3747                 WARN_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
3748
3749                 cur_pos += exts[nr].num_bytes;
3750                 nr++;
3751
3752                 if (cur_pos + offset >= last_byte)
3753                         break;
3754
3755                 if (no_fragment) {
3756                         ret = 1;
3757                         goto out;
3758                 }
3759                 path->slots[0]++;
3760         }
3761
3762         WARN_ON(cur_pos + offset > last_byte);
3763         if (cur_pos + offset < last_byte) {
3764                 ret = -ENOENT;
3765                 goto out;
3766         }
3767         ret = 0;
3768 out:
3769         btrfs_free_path(path);
3770         if (ret) {
3771                 if (exts != *extents)
3772                         kfree(exts);
3773         } else {
3774                 *extents = exts;
3775                 *nr_extents = nr;
3776         }
3777         return ret;
3778 }
3779
3780 static int noinline replace_one_extent(struct btrfs_trans_handle *trans,
3781                                         struct btrfs_root *root,
3782                                         struct btrfs_path *path,
3783                                         struct btrfs_key *extent_key,
3784                                         struct btrfs_key *leaf_key,
3785                                         struct btrfs_ref_path *ref_path,
3786                                         struct disk_extent *new_extents,
3787                                         int nr_extents)
3788 {
3789         struct extent_buffer *leaf;
3790         struct btrfs_file_extent_item *fi;
3791         struct inode *inode = NULL;
3792         struct btrfs_key key;
3793         u64 lock_start = 0;
3794         u64 lock_end = 0;
3795         u64 num_bytes;
3796         u64 ext_offset;
3797         u64 first_pos;
3798         u32 nritems;
3799         int nr_scaned = 0;
3800         int extent_locked = 0;
3801         int ret;
3802
3803         memcpy(&key, leaf_key, sizeof(key));
3804         first_pos = INT_LIMIT(loff_t) - extent_key->offset;
3805         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
3806                 if (key.objectid < ref_path->owner_objectid ||
3807                     (key.objectid == ref_path->owner_objectid &&
3808                      key.type < BTRFS_EXTENT_DATA_KEY)) {
3809                         key.objectid = ref_path->owner_objectid;
3810                         key.type = BTRFS_EXTENT_DATA_KEY;
3811                         key.offset = 0;
3812                 }
3813         }
3814
3815         while (1) {
3816                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
3817                 if (ret < 0)
3818                         goto out;
3819
3820                 leaf = path->nodes[0];
3821                 nritems = btrfs_header_nritems(leaf);
3822 next:
3823                 if (extent_locked && ret > 0) {
3824                         /*
3825                          * the file extent item was modified by someone
3826                          * before the extent got locked.
3827                          */
3828                         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
3829                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
3830                                       lock_end, GFP_NOFS);
3831                         extent_locked = 0;
3832                 }
3833
3834                 if (path->slots[0] >= nritems) {
3835                         if (++nr_scaned > 2)
3836                                 break;
3837
3838                         BUG_ON(extent_locked);
3839                         ret = btrfs_next_leaf(root, path);
3840                         if (ret < 0)
3841                                 goto out;
3842                         if (ret > 0)
3843                                 break;
3844                         leaf = path->nodes[0];
3845                         nritems = btrfs_header_nritems(leaf);
3846                 }
3847
3848                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3849
3850                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
3851                         if ((key.objectid > ref_path->owner_objectid) ||
3852                             (key.objectid == ref_path->owner_objectid &&
3853                              key.type > BTRFS_EXTENT_DATA_KEY) ||
3854                             (key.offset >= first_pos + extent_key->offset))
3855                                 break;
3856                 }
3857
3858                 if (inode && key.objectid != inode->i_ino) {
3859                         BUG_ON(extent_locked);
3860                         btrfs_release_path(root, path);
3861                         mutex_unlock(&inode->i_mutex);
3862                         iput(inode);
3863                         inode = NULL;
3864                         continue;
3865                 }
3866
3867                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
3868                         path->slots[0]++;
3869                         ret = 1;
3870                         goto next;
3871                 }
3872                 fi = btrfs_item_ptr(leaf, path->slots[0],
3873                                     struct btrfs_file_extent_item);
3874                 if ((btrfs_file_extent_type(leaf, fi) !=
3875                      BTRFS_FILE_EXTENT_REG) ||
3876                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3877                      extent_key->objectid)) {
3878                         path->slots[0]++;
3879                         ret = 1;
3880                         goto next;
3881                 }
3882
3883                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
3884                 ext_offset = btrfs_file_extent_offset(leaf, fi);
3885
3886                 if (first_pos > key.offset - ext_offset)
3887                         first_pos = key.offset - ext_offset;
3888
3889                 if (!extent_locked) {
3890                         lock_start = key.offset;
3891                         lock_end = lock_start + num_bytes - 1;
3892                 } else {
3893                         BUG_ON(lock_start != key.offset);
3894                         BUG_ON(lock_end - lock_start + 1 < num_bytes);
3895                 }
3896
3897                 if (!inode) {
3898                         btrfs_release_path(root, path);
3899
3900                         inode = btrfs_iget_locked(root->fs_info->sb,
3901                                                   key.objectid, root);
3902                         if (inode->i_state & I_NEW) {
3903                                 BTRFS_I(inode)->root = root;
3904                                 BTRFS_I(inode)->location.objectid =
3905                                         key.objectid;
3906                                 BTRFS_I(inode)->location.type =
3907                                         BTRFS_INODE_ITEM_KEY;
3908                                 BTRFS_I(inode)->location.offset = 0;
3909                                 btrfs_read_locked_inode(inode);
3910                                 unlock_new_inode(inode);
3911                         }
3912                         /*
3913                          * some code call btrfs_commit_transaction while
3914                          * holding the i_mutex, so we can't use mutex_lock
3915                          * here.
3916                          */
3917                         if (is_bad_inode(inode) ||
3918                             !mutex_trylock(&inode->i_mutex)) {
3919                                 iput(inode);
3920                                 inode = NULL;
3921                                 key.offset = (u64)-1;
3922                                 goto skip;
3923                         }
3924                 }
3925
3926                 if (!extent_locked) {
3927                         struct btrfs_ordered_extent *ordered;
3928
3929                         btrfs_release_path(root, path);
3930
3931                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
3932                                     lock_end, GFP_NOFS);
3933                         ordered = btrfs_lookup_first_ordered_extent(inode,
3934                                                                     lock_end);
3935                         if (ordered &&
3936                             ordered->file_offset <= lock_end &&
3937                             ordered->file_offset + ordered->len > lock_start) {
3938                                 unlock_extent(&BTRFS_I(inode)->io_tree,
3939                                               lock_start, lock_end, GFP_NOFS);
3940                                 btrfs_start_ordered_extent(inode, ordered, 1);
3941                                 btrfs_put_ordered_extent(ordered);
3942                                 key.offset += num_bytes;
3943                                 goto skip;
3944                         }
3945                         if (ordered)
3946                                 btrfs_put_ordered_extent(ordered);
3947
3948                         mutex_lock(&BTRFS_I(inode)->extent_mutex);
3949                         extent_locked = 1;
3950                         continue;
3951                 }
3952
3953                 if (nr_extents == 1) {
3954                         /* update extent pointer in place */
3955                         btrfs_set_file_extent_generation(leaf, fi,
3956                                                 trans->transid);
3957                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
3958                                                 new_extents[0].disk_bytenr);
3959                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
3960                                                 new_extents[0].disk_num_bytes);
3961                         btrfs_set_file_extent_ram_bytes(leaf, fi,
3962                                                 new_extents[0].ram_bytes);
3963                         ext_offset += new_extents[0].offset;
3964                         btrfs_set_file_extent_offset(leaf, fi, ext_offset);
3965                         btrfs_mark_buffer_dirty(leaf);
3966
3967                         btrfs_drop_extent_cache(inode, key.offset,
3968                                                 key.offset + num_bytes - 1, 0);
3969
3970                         ret = btrfs_inc_extent_ref(trans, root,
3971                                                 new_extents[0].disk_bytenr,
3972                                                 new_extents[0].disk_num_bytes,
3973                                                 leaf->start,
3974                                                 root->root_key.objectid,
3975                                                 trans->transid,
3976                                                 key.objectid);
3977                         BUG_ON(ret);
3978
3979                         ret = btrfs_free_extent(trans, root,
3980                                                 extent_key->objectid,
3981                                                 extent_key->offset,
3982                                                 leaf->start,
3983                                                 btrfs_header_owner(leaf),
3984                                                 btrfs_header_generation(leaf),
3985                                                 key.objectid, 0);
3986                         BUG_ON(ret);
3987
3988                         btrfs_release_path(root, path);
3989                         key.offset += num_bytes;
3990                 } else {
3991                         u64 alloc_hint;
3992                         u64 extent_len;
3993                         int i;
3994                         /*
3995                          * drop old extent pointer at first, then insert the
3996                          * new pointers one bye one
3997                          */
3998                         btrfs_release_path(root, path);
3999                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
4000                                                  key.offset + num_bytes,
4001                                                  key.offset, &alloc_hint);
4002                         BUG_ON(ret);
4003
4004                         for (i = 0; i < nr_extents; i++) {
4005                                 if (ext_offset >= new_extents[i].num_bytes) {
4006                                         ext_offset -= new_extents[i].num_bytes;
4007                                         continue;
4008                                 }
4009                                 extent_len = min(new_extents[i].num_bytes -
4010                                                  ext_offset, num_bytes);
4011
4012                                 ret = btrfs_insert_empty_item(trans, root,
4013                                                               path, &key,
4014                                                               sizeof(*fi));
4015                                 BUG_ON(ret);
4016
4017                                 leaf = path->nodes[0];
4018                                 fi = btrfs_item_ptr(leaf, path->slots[0],
4019                                                 struct btrfs_file_extent_item);
4020                                 btrfs_set_file_extent_generation(leaf, fi,
4021                                                         trans->transid);
4022                                 btrfs_set_file_extent_type(leaf, fi,
4023                                                         BTRFS_FILE_EXTENT_REG);
4024                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4025                                                 new_extents[i].disk_bytenr);
4026                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4027                                                 new_extents[i].disk_num_bytes);
4028                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
4029                                                 new_extents[i].ram_bytes);
4030
4031                                 btrfs_set_file_extent_compression(leaf, fi,
4032                                                 new_extents[i].compression);
4033                                 btrfs_set_file_extent_encryption(leaf, fi,
4034                                                 new_extents[i].encryption);
4035                                 btrfs_set_file_extent_other_encoding(leaf, fi,
4036                                                 new_extents[i].other_encoding);
4037
4038                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4039                                                         extent_len);
4040                                 ext_offset += new_extents[i].offset;
4041                                 btrfs_set_file_extent_offset(leaf, fi,
4042                                                         ext_offset);
4043                                 btrfs_mark_buffer_dirty(leaf);
4044
4045                                 btrfs_drop_extent_cache(inode, key.offset,
4046                                                 key.offset + extent_len - 1, 0);
4047
4048                                 ret = btrfs_inc_extent_ref(trans, root,
4049                                                 new_extents[i].disk_bytenr,
4050                                                 new_extents[i].disk_num_bytes,
4051                                                 leaf->start,
4052                                                 root->root_key.objectid,
4053                                                 trans->transid, key.objectid);
4054                                 BUG_ON(ret);
4055                                 btrfs_release_path(root, path);
4056
4057                                 inode_add_bytes(inode, extent_len);
4058
4059                                 ext_offset = 0;
4060                                 num_bytes -= extent_len;
4061                                 key.offset += extent_len;
4062
4063                                 if (num_bytes == 0)
4064                                         break;
4065                         }
4066                         BUG_ON(i >= nr_extents);
4067                 }
4068
4069                 if (extent_locked) {
4070                         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
4071                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4072                                       lock_end, GFP_NOFS);
4073                         extent_locked = 0;
4074                 }
4075 skip:
4076                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
4077                     key.offset >= first_pos + extent_key->offset)
4078                         break;
4079
4080                 cond_resched();
4081         }
4082         ret = 0;
4083 out:
4084         btrfs_release_path(root, path);
4085         if (inode) {
4086                 mutex_unlock(&inode->i_mutex);
4087                 if (extent_locked) {
4088                         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
4089                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4090                                       lock_end, GFP_NOFS);
4091                 }
4092                 iput(inode);
4093         }
4094         return ret;
4095 }
4096
4097 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
4098                                struct btrfs_root *root,
4099                                struct extent_buffer *buf, u64 orig_start)
4100 {
4101         int level;
4102         int ret;
4103
4104         BUG_ON(btrfs_header_generation(buf) != trans->transid);
4105         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
4106
4107         level = btrfs_header_level(buf);
4108         if (level == 0) {
4109                 struct btrfs_leaf_ref *ref;
4110                 struct btrfs_leaf_ref *orig_ref;
4111
4112                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
4113                 if (!orig_ref)
4114                         return -ENOENT;
4115
4116                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
4117                 if (!ref) {
4118                         btrfs_free_leaf_ref(root, orig_ref);
4119                         return -ENOMEM;
4120                 }
4121
4122                 ref->nritems = orig_ref->nritems;
4123                 memcpy(ref->extents, orig_ref->extents,
4124                         sizeof(ref->extents[0]) * ref->nritems);
4125
4126                 btrfs_free_leaf_ref(root, orig_ref);
4127
4128                 ref->root_gen = trans->transid;
4129                 ref->bytenr = buf->start;
4130                 ref->owner = btrfs_header_owner(buf);
4131                 ref->generation = btrfs_header_generation(buf);
4132                 ret = btrfs_add_leaf_ref(root, ref, 0);
4133                 WARN_ON(ret);
4134                 btrfs_free_leaf_ref(root, ref);
4135         }
4136         return 0;
4137 }
4138
4139 static int noinline invalidate_extent_cache(struct btrfs_root *root,
4140                                         struct extent_buffer *leaf,
4141                                         struct btrfs_block_group_cache *group,
4142                                         struct btrfs_root *target_root)
4143 {
4144         struct btrfs_key key;
4145         struct inode *inode = NULL;
4146         struct btrfs_file_extent_item *fi;
4147         u64 num_bytes;
4148         u64 skip_objectid = 0;
4149         u32 nritems;
4150         u32 i;
4151
4152         nritems = btrfs_header_nritems(leaf);
4153         for (i = 0; i < nritems; i++) {
4154                 btrfs_item_key_to_cpu(leaf, &key, i);
4155                 if (key.objectid == skip_objectid ||
4156                     key.type != BTRFS_EXTENT_DATA_KEY)
4157                         continue;
4158                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4159                 if (btrfs_file_extent_type(leaf, fi) ==
4160                     BTRFS_FILE_EXTENT_INLINE)
4161                         continue;
4162                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4163                         continue;
4164                 if (!inode || inode->i_ino != key.objectid) {
4165                         iput(inode);
4166                         inode = btrfs_ilookup(target_root->fs_info->sb,
4167                                               key.objectid, target_root, 1);
4168                 }
4169                 if (!inode) {
4170                         skip_objectid = key.objectid;
4171                         continue;
4172                 }
4173                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4174
4175                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4176                             key.offset + num_bytes - 1, GFP_NOFS);
4177                 mutex_lock(&BTRFS_I(inode)->extent_mutex);
4178                 btrfs_drop_extent_cache(inode, key.offset,
4179                                         key.offset + num_bytes - 1, 1);
4180                 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
4181                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
4182                               key.offset + num_bytes - 1, GFP_NOFS);
4183                 cond_resched();
4184         }
4185         iput(inode);
4186         return 0;
4187 }
4188
4189 static int noinline replace_extents_in_leaf(struct btrfs_trans_handle *trans,
4190                                         struct btrfs_root *root,
4191                                         struct extent_buffer *leaf,
4192                                         struct btrfs_block_group_cache *group,
4193                                         struct inode *reloc_inode)
4194 {
4195         struct btrfs_key key;
4196         struct btrfs_key extent_key;
4197         struct btrfs_file_extent_item *fi;
4198         struct btrfs_leaf_ref *ref;
4199         struct disk_extent *new_extent;
4200         u64 bytenr;
4201         u64 num_bytes;
4202         u32 nritems;
4203         u32 i;
4204         int ext_index;
4205         int nr_extent;
4206         int ret;
4207
4208         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
4209         BUG_ON(!new_extent);
4210
4211         ref = btrfs_lookup_leaf_ref(root, leaf->start);
4212         BUG_ON(!ref);
4213
4214         ext_index = -1;
4215         nritems = btrfs_header_nritems(leaf);
4216         for (i = 0; i < nritems; i++) {
4217                 btrfs_item_key_to_cpu(leaf, &key, i);
4218                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
4219                         continue;
4220                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
4221                 if (btrfs_file_extent_type(leaf, fi) ==
4222                     BTRFS_FILE_EXTENT_INLINE)
4223                         continue;
4224                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
4225                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
4226                 if (bytenr == 0)
4227                         continue;
4228
4229                 ext_index++;
4230                 if (bytenr >= group->key.objectid + group->key.offset ||
4231                     bytenr + num_bytes <= group->key.objectid)
4232                         continue;
4233
4234                 extent_key.objectid = bytenr;
4235                 extent_key.offset = num_bytes;
4236                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4237                 nr_extent = 1;
4238                 ret = get_new_locations(reloc_inode, &extent_key,
4239                                         group->key.objectid, 1,
4240                                         &new_extent, &nr_extent);
4241                 if (ret > 0)
4242                         continue;
4243                 BUG_ON(ret < 0);
4244
4245                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
4246                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
4247                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
4248                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
4249
4250                 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
4251                 btrfs_set_file_extent_ram_bytes(leaf, fi,
4252                                                 new_extent->ram_bytes);
4253                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4254                                                 new_extent->disk_bytenr);
4255                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4256                                                 new_extent->disk_num_bytes);
4257                 new_extent->offset += btrfs_file_extent_offset(leaf, fi);
4258                 btrfs_set_file_extent_offset(leaf, fi, new_extent->offset);
4259                 btrfs_mark_buffer_dirty(leaf);
4260
4261                 ret = btrfs_inc_extent_ref(trans, root,
4262                                         new_extent->disk_bytenr,
4263                                         new_extent->disk_num_bytes,
4264                                         leaf->start,
4265                                         root->root_key.objectid,
4266                                         trans->transid, key.objectid);
4267                 BUG_ON(ret);
4268                 ret = btrfs_free_extent(trans, root,
4269                                         bytenr, num_bytes, leaf->start,
4270                                         btrfs_header_owner(leaf),
4271                                         btrfs_header_generation(leaf),
4272                                         key.objectid, 0);
4273                 BUG_ON(ret);
4274                 cond_resched();
4275         }
4276         kfree(new_extent);
4277         BUG_ON(ext_index + 1 != ref->nritems);
4278         btrfs_free_leaf_ref(root, ref);
4279         return 0;
4280 }
4281
4282 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
4283                           struct btrfs_root *root)
4284 {
4285         struct btrfs_root *reloc_root;
4286         int ret;
4287
4288         if (root->reloc_root) {
4289                 reloc_root = root->reloc_root;
4290                 root->reloc_root = NULL;
4291                 list_add(&reloc_root->dead_list,
4292                          &root->fs_info->dead_reloc_roots);
4293
4294                 btrfs_set_root_bytenr(&reloc_root->root_item,
4295                                       reloc_root->node->start);
4296                 btrfs_set_root_level(&root->root_item,
4297                                      btrfs_header_level(reloc_root->node));
4298                 memset(&reloc_root->root_item.drop_progress, 0,
4299                         sizeof(struct btrfs_disk_key));
4300                 reloc_root->root_item.drop_level = 0;
4301
4302                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4303                                         &reloc_root->root_key,
4304                                         &reloc_root->root_item);
4305                 BUG_ON(ret);
4306         }
4307         return 0;
4308 }
4309
4310 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
4311 {
4312         struct btrfs_trans_handle *trans;
4313         struct btrfs_root *reloc_root;
4314         struct btrfs_root *prev_root = NULL;
4315         struct list_head dead_roots;
4316         int ret;
4317         unsigned long nr;
4318
4319         INIT_LIST_HEAD(&dead_roots);
4320         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
4321
4322         while (!list_empty(&dead_roots)) {
4323                 reloc_root = list_entry(dead_roots.prev,
4324                                         struct btrfs_root, dead_list);
4325                 list_del_init(&reloc_root->dead_list);
4326
4327                 BUG_ON(reloc_root->commit_root != NULL);
4328                 while (1) {
4329                         trans = btrfs_join_transaction(root, 1);
4330                         BUG_ON(!trans);
4331
4332                         mutex_lock(&root->fs_info->drop_mutex);
4333                         ret = btrfs_drop_snapshot(trans, reloc_root);
4334                         if (ret != -EAGAIN)
4335                                 break;
4336                         mutex_unlock(&root->fs_info->drop_mutex);
4337
4338                         nr = trans->blocks_used;
4339                         ret = btrfs_end_transaction(trans, root);
4340                         BUG_ON(ret);
4341                         btrfs_btree_balance_dirty(root, nr);
4342                 }
4343
4344                 free_extent_buffer(reloc_root->node);
4345
4346                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
4347                                      &reloc_root->root_key);
4348                 BUG_ON(ret);
4349                 mutex_unlock(&root->fs_info->drop_mutex);
4350
4351                 nr = trans->blocks_used;
4352                 ret = btrfs_end_transaction(trans, root);
4353                 BUG_ON(ret);
4354                 btrfs_btree_balance_dirty(root, nr);
4355
4356                 kfree(prev_root);
4357                 prev_root = reloc_root;
4358         }
4359         if (prev_root) {
4360                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
4361                 kfree(prev_root);
4362         }
4363         return 0;
4364 }
4365
4366 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
4367 {
4368         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
4369         return 0;
4370 }
4371
4372 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
4373 {
4374         struct btrfs_root *reloc_root;
4375         struct btrfs_trans_handle *trans;
4376         struct btrfs_key location;
4377         int found;
4378         int ret;
4379
4380         mutex_lock(&root->fs_info->tree_reloc_mutex);
4381         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
4382         BUG_ON(ret);
4383         found = !list_empty(&root->fs_info->dead_reloc_roots);
4384         mutex_unlock(&root->fs_info->tree_reloc_mutex);
4385
4386         if (found) {
4387                 trans = btrfs_start_transaction(root, 1);
4388                 BUG_ON(!trans);
4389                 ret = btrfs_commit_transaction(trans, root);
4390                 BUG_ON(ret);
4391         }
4392
4393         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
4394         location.offset = (u64)-1;
4395         location.type = BTRFS_ROOT_ITEM_KEY;
4396
4397         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
4398         BUG_ON(!reloc_root);
4399         btrfs_orphan_cleanup(reloc_root);
4400         return 0;
4401 }
4402
4403 static int noinline init_reloc_tree(struct btrfs_trans_handle *trans,
4404                                     struct btrfs_root *root)
4405 {
4406         struct btrfs_root *reloc_root;
4407         struct extent_buffer *eb;
4408         struct btrfs_root_item *root_item;
4409         struct btrfs_key root_key;
4410         int ret;
4411
4412         BUG_ON(!root->ref_cows);
4413         if (root->reloc_root)
4414                 return 0;
4415
4416         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
4417         BUG_ON(!root_item);
4418
4419         ret = btrfs_copy_root(trans, root, root->commit_root,
4420                               &eb, BTRFS_TREE_RELOC_OBJECTID);
4421         BUG_ON(ret);
4422
4423         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4424         root_key.offset = root->root_key.objectid;
4425         root_key.type = BTRFS_ROOT_ITEM_KEY;
4426
4427         memcpy(root_item, &root->root_item, sizeof(root_item));
4428         btrfs_set_root_refs(root_item, 0);
4429         btrfs_set_root_bytenr(root_item, eb->start);
4430         btrfs_set_root_level(root_item, btrfs_header_level(eb));
4431
4432         btrfs_tree_unlock(eb);
4433         free_extent_buffer(eb);
4434
4435         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
4436                                 &root_key, root_item);
4437         BUG_ON(ret);
4438         kfree(root_item);
4439
4440         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
4441                                                  &root_key);
4442         BUG_ON(!reloc_root);
4443         reloc_root->last_trans = trans->transid;
4444         reloc_root->commit_root = NULL;
4445         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
4446
4447         root->reloc_root = reloc_root;
4448         return 0;
4449 }
4450
4451 /*
4452  * Core function of space balance.
4453  *
4454  * The idea is using reloc trees to relocate tree blocks in reference
4455  * counted roots. There is one reloc tree for each subvol, and all
4456  * reloc trees share same root key objectid. Reloc trees are snapshots
4457  * of the latest committed roots of subvols (root->commit_root).
4458  *
4459  * To relocate a tree block referenced by a subvol, there are two steps.
4460  * COW the block through subvol's reloc tree, then update block pointer
4461  * in the subvol to point to the new block. Since all reloc trees share
4462  * same root key objectid, doing special handing for tree blocks owned
4463  * by them is easy. Once a tree block has been COWed in one reloc tree,
4464  * we can use the resulting new block directly when the same block is
4465  * required to COW again through other reloc trees. By this way, relocated
4466  * tree blocks are shared between reloc trees, so they are also shared
4467  * between subvols.
4468  */
4469 static int noinline relocate_one_path(struct btrfs_trans_handle *trans,
4470                                       struct btrfs_root *root,
4471                                       struct btrfs_path *path,
4472                                       struct btrfs_key *first_key,
4473                                       struct btrfs_ref_path *ref_path,
4474                                       struct btrfs_block_group_cache *group,
4475                                       struct inode *reloc_inode)
4476 {
4477         struct btrfs_root *reloc_root;
4478         struct extent_buffer *eb = NULL;
4479         struct btrfs_key *keys;
4480         u64 *nodes;
4481         int level;
4482         int shared_level;
4483         int lowest_level = 0;
4484         int ret;
4485
4486         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
4487                 lowest_level = ref_path->owner_objectid;
4488
4489         if (!root->ref_cows) {
4490                 path->lowest_level = lowest_level;
4491                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
4492                 BUG_ON(ret < 0);
4493                 path->lowest_level = 0;
4494                 btrfs_release_path(root, path);
4495                 return 0;
4496         }
4497
4498         mutex_lock(&root->fs_info->tree_reloc_mutex);
4499         ret = init_reloc_tree(trans, root);
4500         BUG_ON(ret);
4501         reloc_root = root->reloc_root;
4502
4503         shared_level = ref_path->shared_level;
4504         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
4505
4506         keys = ref_path->node_keys;
4507         nodes = ref_path->new_nodes;
4508         memset(&keys[shared_level + 1], 0,
4509                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
4510         memset(&nodes[shared_level + 1], 0,
4511                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
4512
4513         if (nodes[lowest_level] == 0) {
4514                 path->lowest_level = lowest_level;
4515                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
4516                                         0, 1);
4517                 BUG_ON(ret);
4518                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
4519                         eb = path->nodes[level];
4520                         if (!eb || eb == reloc_root->node)
4521                                 break;
4522                         nodes[level] = eb->start;
4523                         if (level == 0)
4524                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
4525                         else
4526                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
4527                 }
4528                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4529                         eb = path->nodes[0];
4530                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
4531                                                       group, reloc_inode);
4532                         BUG_ON(ret);
4533                 }
4534                 btrfs_release_path(reloc_root, path);
4535         } else {
4536                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
4537                                        lowest_level);
4538                 BUG_ON(ret);
4539         }
4540
4541         /*
4542          * replace tree blocks in the fs tree with tree blocks in
4543          * the reloc tree.
4544          */
4545         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
4546         BUG_ON(ret < 0);
4547
4548         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4549                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
4550                                         0, 0);
4551                 BUG_ON(ret);
4552                 extent_buffer_get(path->nodes[0]);
4553                 eb = path->nodes[0];
4554                 btrfs_release_path(reloc_root, path);
4555                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
4556                 BUG_ON(ret);
4557                 free_extent_buffer(eb);
4558         }
4559
4560         mutex_unlock(&root->fs_info->tree_reloc_mutex);
4561         path->lowest_level = 0;
4562         return 0;
4563 }
4564
4565 static int noinline relocate_tree_block(struct btrfs_trans_handle *trans,
4566                                         struct btrfs_root *root,
4567                                         struct btrfs_path *path,
4568                                         struct btrfs_key *first_key,
4569                                         struct btrfs_ref_path *ref_path)
4570 {
4571         int ret;
4572
4573         ret = relocate_one_path(trans, root, path, first_key,
4574                                 ref_path, NULL, NULL);
4575         BUG_ON(ret);
4576
4577         if (root == root->fs_info->extent_root)
4578                 btrfs_extent_post_op(trans, root);
4579
4580         return 0;
4581 }
4582
4583 static int noinline del_extent_zero(struct btrfs_trans_handle *trans,
4584                                     struct btrfs_root *extent_root,
4585                                     struct btrfs_path *path,
4586                                     struct btrfs_key *extent_key)
4587 {
4588         int ret;
4589
4590         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
4591         if (ret)
4592                 goto out;
4593         ret = btrfs_del_item(trans, extent_root, path);
4594 out:
4595         btrfs_release_path(extent_root, path);
4596         return ret;
4597 }
4598
4599 static struct btrfs_root noinline *read_ref_root(struct btrfs_fs_info *fs_info,
4600                                                 struct btrfs_ref_path *ref_path)
4601 {
4602         struct btrfs_key root_key;
4603
4604         root_key.objectid = ref_path->root_objectid;
4605         root_key.type = BTRFS_ROOT_ITEM_KEY;
4606         if (is_cowonly_root(ref_path->root_objectid))
4607                 root_key.offset = 0;
4608         else
4609                 root_key.offset = (u64)-1;
4610
4611         return btrfs_read_fs_root_no_name(fs_info, &root_key);
4612 }
4613
4614 static int noinline relocate_one_extent(struct btrfs_root *extent_root,
4615                                         struct btrfs_path *path,
4616                                         struct btrfs_key *extent_key,
4617                                         struct btrfs_block_group_cache *group,
4618                                         struct inode *reloc_inode, int pass)
4619 {
4620         struct btrfs_trans_handle *trans;
4621         struct btrfs_root *found_root;
4622         struct btrfs_ref_path *ref_path = NULL;
4623         struct disk_extent *new_extents = NULL;
4624         int nr_extents = 0;
4625         int loops;
4626         int ret;
4627         int level;
4628         struct btrfs_key first_key;
4629         u64 prev_block = 0;
4630
4631
4632         trans = btrfs_start_transaction(extent_root, 1);
4633         BUG_ON(!trans);
4634
4635         if (extent_key->objectid == 0) {
4636                 ret = del_extent_zero(trans, extent_root, path, extent_key);
4637                 goto out;
4638         }
4639
4640         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
4641         if (!ref_path) {
4642                ret = -ENOMEM;
4643                goto out;
4644         }
4645
4646         for (loops = 0; ; loops++) {
4647                 if (loops == 0) {
4648                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
4649                                                    extent_key->objectid);
4650                 } else {
4651                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
4652                 }
4653                 if (ret < 0)
4654                         goto out;
4655                 if (ret > 0)
4656                         break;
4657
4658                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
4659                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
4660                         continue;
4661
4662                 found_root = read_ref_root(extent_root->fs_info, ref_path);
4663                 BUG_ON(!found_root);
4664                 /*
4665                  * for reference counted tree, only process reference paths
4666                  * rooted at the latest committed root.
4667                  */
4668                 if (found_root->ref_cows &&
4669                     ref_path->root_generation != found_root->root_key.offset)
4670                         continue;
4671
4672                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
4673                         if (pass == 0) {
4674                                 /*
4675                                  * copy data extents to new locations
4676                                  */
4677                                 u64 group_start = group->key.objectid;
4678                                 ret = relocate_data_extent(reloc_inode,
4679                                                            extent_key,
4680                                                            group_start);
4681                                 if (ret < 0)
4682                                         goto out;
4683                                 break;
4684                         }
4685                         level = 0;
4686                 } else {
4687                         level = ref_path->owner_objectid;
4688                 }
4689
4690                 if (prev_block != ref_path->nodes[level]) {
4691                         struct extent_buffer *eb;
4692                         u64 block_start = ref_path->nodes[level];
4693                         u64 block_size = btrfs_level_size(found_root, level);
4694
4695                         eb = read_tree_block(found_root, block_start,
4696                                              block_size, 0);
4697                         btrfs_tree_lock(eb);
4698                         BUG_ON(level != btrfs_header_level(eb));
4699
4700                         if (level == 0)
4701                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
4702                         else
4703                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
4704
4705                         btrfs_tree_unlock(eb);
4706                         free_extent_buffer(eb);
4707                         prev_block = block_start;
4708                 }
4709
4710                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
4711                     pass >= 2) {
4712                         /*
4713                          * use fallback method to process the remaining
4714                          * references.
4715                          */
4716                         if (!new_extents) {
4717                                 u64 group_start = group->key.objectid;
4718                                 ret = get_new_locations(reloc_inode,
4719                                                         extent_key,
4720                                                         group_start, 0,
4721                                                         &new_extents,
4722                                                         &nr_extents);
4723                                 if (ret < 0)
4724                                         goto out;
4725                         }
4726                         btrfs_record_root_in_trans(found_root);
4727                         ret = replace_one_extent(trans, found_root,
4728                                                 path, extent_key,
4729                                                 &first_key, ref_path,
4730                                                 new_extents, nr_extents);
4731                         if (ret < 0)
4732                                 goto out;
4733                         continue;
4734                 }
4735
4736                 btrfs_record_root_in_trans(found_root);
4737                 if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4738                         ret = relocate_tree_block(trans, found_root, path,
4739                                                   &first_key, ref_path);
4740                 } else {
4741                         /*
4742                          * try to update data extent references while
4743                          * keeping metadata shared between snapshots.
4744                          */
4745                         ret = relocate_one_path(trans, found_root, path,
4746                                                 &first_key, ref_path,
4747                                                 group, reloc_inode);
4748                 }
4749                 if (ret < 0)
4750                         goto out;
4751         }
4752         ret = 0;
4753 out:
4754         btrfs_end_transaction(trans, extent_root);
4755         kfree(new_extents);
4756         kfree(ref_path);
4757         return ret;
4758 }
4759
4760 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
4761 {
4762         u64 num_devices;
4763         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
4764                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
4765
4766         num_devices = root->fs_info->fs_devices->num_devices;
4767         if (num_devices == 1) {
4768                 stripped |= BTRFS_BLOCK_GROUP_DUP;
4769                 stripped = flags & ~stripped;
4770
4771                 /* turn raid0 into single device chunks */
4772                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
4773                         return stripped;
4774
4775                 /* turn mirroring into duplication */
4776                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
4777                              BTRFS_BLOCK_GROUP_RAID10))
4778                         return stripped | BTRFS_BLOCK_GROUP_DUP;
4779                 return flags;
4780         } else {
4781                 /* they already had raid on here, just return */
4782                 if (flags & stripped)
4783                         return flags;
4784
4785                 stripped |= BTRFS_BLOCK_GROUP_DUP;
4786                 stripped = flags & ~stripped;
4787
4788                 /* switch duplicated blocks with raid1 */
4789                 if (flags & BTRFS_BLOCK_GROUP_DUP)
4790                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
4791
4792                 /* turn single device chunks into raid0 */
4793                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
4794         }
4795         return flags;
4796 }
4797
4798 int __alloc_chunk_for_shrink(struct btrfs_root *root,
4799                      struct btrfs_block_group_cache *shrink_block_group,
4800                      int force)
4801 {
4802         struct btrfs_trans_handle *trans;
4803         u64 new_alloc_flags;
4804         u64 calc;
4805
4806         spin_lock(&shrink_block_group->lock);
4807         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
4808                 spin_unlock(&shrink_block_group->lock);
4809
4810                 trans = btrfs_start_transaction(root, 1);
4811                 spin_lock(&shrink_block_group->lock);
4812
4813                 new_alloc_flags = update_block_group_flags(root,
4814                                                    shrink_block_group->flags);
4815                 if (new_alloc_flags != shrink_block_group->flags) {
4816                         calc =
4817                              btrfs_block_group_used(&shrink_block_group->item);
4818                 } else {
4819                         calc = shrink_block_group->key.offset;
4820                 }
4821                 spin_unlock(&shrink_block_group->lock);
4822
4823                 do_chunk_alloc(trans, root->fs_info->extent_root,
4824                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
4825
4826                 btrfs_end_transaction(trans, root);
4827         } else
4828                 spin_unlock(&shrink_block_group->lock);
4829         return 0;
4830 }
4831
4832 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4833                                  struct btrfs_root *root,
4834                                  u64 objectid, u64 size)
4835 {
4836         struct btrfs_path *path;
4837         struct btrfs_inode_item *item;
4838         struct extent_buffer *leaf;
4839         int ret;
4840
4841         path = btrfs_alloc_path();
4842         if (!path)
4843                 return -ENOMEM;
4844
4845         ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4846         if (ret)
4847                 goto out;
4848
4849         leaf = path->nodes[0];
4850         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4851         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4852         btrfs_set_inode_generation(leaf, item, 1);
4853         btrfs_set_inode_size(leaf, item, size);
4854         btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4855         btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NODATASUM);
4856         btrfs_mark_buffer_dirty(leaf);
4857         btrfs_release_path(root, path);
4858 out:
4859         btrfs_free_path(path);
4860         return ret;
4861 }
4862
4863 static struct inode noinline *create_reloc_inode(struct btrfs_fs_info *fs_info,
4864                                         struct btrfs_block_group_cache *group)
4865 {
4866         struct inode *inode = NULL;
4867         struct btrfs_trans_handle *trans;
4868         struct btrfs_root *root;
4869         struct btrfs_key root_key;
4870         u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4871         int err = 0;
4872
4873         root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
4874         root_key.type = BTRFS_ROOT_ITEM_KEY;
4875         root_key.offset = (u64)-1;
4876         root = btrfs_read_fs_root_no_name(fs_info, &root_key);
4877         if (IS_ERR(root))
4878                 return ERR_CAST(root);
4879
4880         trans = btrfs_start_transaction(root, 1);
4881         BUG_ON(!trans);
4882
4883         err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
4884         if (err)
4885                 goto out;
4886
4887         err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
4888         BUG_ON(err);
4889
4890         err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
4891                                        group->key.offset, 0, group->key.offset,
4892                                        0, 0, 0);
4893         BUG_ON(err);
4894
4895         inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
4896         if (inode->i_state & I_NEW) {
4897                 BTRFS_I(inode)->root = root;
4898                 BTRFS_I(inode)->location.objectid = objectid;
4899                 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
4900                 BTRFS_I(inode)->location.offset = 0;
4901                 btrfs_read_locked_inode(inode);
4902                 unlock_new_inode(inode);
4903                 BUG_ON(is_bad_inode(inode));
4904         } else {
4905                 BUG_ON(1);
4906         }
4907
4908         err = btrfs_orphan_add(trans, inode);
4909 out:
4910         btrfs_end_transaction(trans, root);
4911         if (err) {
4912                 if (inode)
4913                         iput(inode);
4914                 inode = ERR_PTR(err);
4915         }
4916         return inode;
4917 }
4918
4919 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
4920 {
4921         struct btrfs_trans_handle *trans;
4922         struct btrfs_path *path;
4923         struct btrfs_fs_info *info = root->fs_info;
4924         struct extent_buffer *leaf;
4925         struct inode *reloc_inode;
4926         struct btrfs_block_group_cache *block_group;
4927         struct btrfs_key key;
4928         u64 cur_byte;
4929         u64 total_found;
4930         u32 nritems;
4931         int ret;
4932         int progress;
4933         int pass = 0;
4934
4935         root = root->fs_info->extent_root;
4936
4937         block_group = btrfs_lookup_block_group(info, group_start);
4938         BUG_ON(!block_group);
4939
4940         printk("btrfs relocating block group %llu flags %llu\n",
4941                (unsigned long long)block_group->key.objectid,
4942                (unsigned long long)block_group->flags);
4943
4944         path = btrfs_alloc_path();
4945         BUG_ON(!path);
4946
4947         reloc_inode = create_reloc_inode(info, block_group);
4948         BUG_ON(IS_ERR(reloc_inode));
4949
4950         __alloc_chunk_for_shrink(root, block_group, 1);
4951         block_group->ro = 1;
4952         block_group->space_info->total_bytes -= block_group->key.offset;
4953
4954         btrfs_start_delalloc_inodes(info->tree_root);
4955         btrfs_wait_ordered_extents(info->tree_root, 0);
4956 again:
4957         total_found = 0;
4958         progress = 0;
4959         key.objectid = block_group->key.objectid;
4960         key.offset = 0;
4961         key.type = 0;
4962         cur_byte = key.objectid;
4963
4964         trans = btrfs_start_transaction(info->tree_root, 1);
4965         btrfs_commit_transaction(trans, info->tree_root);
4966
4967         mutex_lock(&root->fs_info->cleaner_mutex);
4968         btrfs_clean_old_snapshots(info->tree_root);
4969         btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
4970         mutex_unlock(&root->fs_info->cleaner_mutex);
4971
4972         while(1) {
4973                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4974                 if (ret < 0)
4975                         goto out;
4976 next:
4977                 leaf = path->nodes[0];
4978                 nritems = btrfs_header_nritems(leaf);
4979                 if (path->slots[0] >= nritems) {
4980                         ret = btrfs_next_leaf(root, path);
4981                         if (ret < 0)
4982                                 goto out;
4983                         if (ret == 1) {
4984                                 ret = 0;
4985                                 break;
4986                         }
4987                         leaf = path->nodes[0];
4988                         nritems = btrfs_header_nritems(leaf);
4989                 }
4990
4991                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4992
4993                 if (key.objectid >= block_group->key.objectid +
4994                     block_group->key.offset)
4995                         break;
4996
4997                 if (progress && need_resched()) {
4998                         btrfs_release_path(root, path);
4999                         cond_resched();
5000                         progress = 0;
5001                         continue;
5002                 }
5003                 progress = 1;
5004
5005                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
5006                     key.objectid + key.offset <= cur_byte) {
5007                         path->slots[0]++;
5008                         goto next;
5009                 }
5010
5011                 total_found++;
5012                 cur_byte = key.objectid + key.offset;
5013                 btrfs_release_path(root, path);
5014
5015                 __alloc_chunk_for_shrink(root, block_group, 0);
5016                 ret = relocate_one_extent(root, path, &key, block_group,
5017                                           reloc_inode, pass);
5018                 BUG_ON(ret < 0);
5019
5020                 key.objectid = cur_byte;
5021                 key.type = 0;
5022                 key.offset = 0;
5023         }
5024
5025         btrfs_release_path(root, path);
5026
5027         if (pass == 0) {
5028                 btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
5029                 invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
5030                 WARN_ON(reloc_inode->i_mapping->nrpages);
5031         }
5032
5033         if (total_found > 0) {
5034                 printk("btrfs found %llu extents in pass %d\n",
5035                        (unsigned long long)total_found, pass);
5036                 pass++;
5037                 goto again;
5038         }
5039
5040         /* delete reloc_inode */
5041         iput(reloc_inode);
5042
5043         /* unpin extents in this range */
5044         trans = btrfs_start_transaction(info->tree_root, 1);
5045         btrfs_commit_transaction(trans, info->tree_root);
5046
5047         spin_lock(&block_group->lock);
5048         WARN_ON(block_group->pinned > 0);
5049         WARN_ON(block_group->reserved > 0);
5050         WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
5051         spin_unlock(&block_group->lock);
5052         ret = 0;
5053 out:
5054         btrfs_free_path(path);
5055         return ret;
5056 }
5057
5058 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
5059                            struct btrfs_key *key)
5060 {
5061         int ret = 0;
5062         struct btrfs_key found_key;
5063         struct extent_buffer *leaf;
5064         int slot;
5065
5066         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
5067         if (ret < 0)
5068                 goto out;
5069
5070         while(1) {
5071                 slot = path->slots[0];
5072                 leaf = path->nodes[0];
5073                 if (slot >= btrfs_header_nritems(leaf)) {
5074                         ret = btrfs_next_leaf(root, path);
5075                         if (ret == 0)
5076                                 continue;
5077                         if (ret < 0)
5078                                 goto out;
5079                         break;
5080                 }
5081                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5082
5083                 if (found_key.objectid >= key->objectid &&
5084                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
5085                         ret = 0;
5086                         goto out;
5087                 }
5088                 path->slots[0]++;
5089         }
5090         ret = -ENOENT;
5091 out:
5092         return ret;
5093 }
5094
5095 int btrfs_free_block_groups(struct btrfs_fs_info *info)
5096 {
5097         struct btrfs_block_group_cache *block_group;
5098         struct rb_node *n;
5099
5100         spin_lock(&info->block_group_cache_lock);
5101         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
5102                 block_group = rb_entry(n, struct btrfs_block_group_cache,
5103                                        cache_node);
5104
5105                 spin_unlock(&info->block_group_cache_lock);
5106                 btrfs_remove_free_space_cache(block_group);
5107                 spin_lock(&info->block_group_cache_lock);
5108
5109                 rb_erase(&block_group->cache_node,
5110                          &info->block_group_cache_tree);
5111                 down_write(&block_group->space_info->groups_sem);
5112                 list_del(&block_group->list);
5113                 up_write(&block_group->space_info->groups_sem);
5114                 kfree(block_group);
5115         }
5116         spin_unlock(&info->block_group_cache_lock);
5117         return 0;
5118 }
5119
5120 int btrfs_read_block_groups(struct btrfs_root *root)
5121 {
5122         struct btrfs_path *path;
5123         int ret;
5124         struct btrfs_block_group_cache *cache;
5125         struct btrfs_fs_info *info = root->fs_info;
5126         struct btrfs_space_info *space_info;
5127         struct btrfs_key key;
5128         struct btrfs_key found_key;
5129         struct extent_buffer *leaf;
5130
5131         root = info->extent_root;
5132         key.objectid = 0;
5133         key.offset = 0;
5134         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
5135         path = btrfs_alloc_path();
5136         if (!path)
5137                 return -ENOMEM;
5138
5139         while(1) {
5140                 ret = find_first_block_group(root, path, &key);
5141                 if (ret > 0) {
5142                         ret = 0;
5143                         goto error;
5144                 }
5145                 if (ret != 0)
5146                         goto error;
5147
5148                 leaf = path->nodes[0];
5149                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5150                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
5151                 if (!cache) {
5152                         ret = -ENOMEM;
5153                         break;
5154                 }
5155
5156                 spin_lock_init(&cache->lock);
5157                 mutex_init(&cache->alloc_mutex);
5158                 INIT_LIST_HEAD(&cache->list);
5159                 read_extent_buffer(leaf, &cache->item,
5160                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
5161                                    sizeof(cache->item));
5162                 memcpy(&cache->key, &found_key, sizeof(found_key));
5163
5164                 key.objectid = found_key.objectid + found_key.offset;
5165                 btrfs_release_path(root, path);
5166                 cache->flags = btrfs_block_group_flags(&cache->item);
5167
5168                 ret = update_space_info(info, cache->flags, found_key.offset,
5169                                         btrfs_block_group_used(&cache->item),
5170                                         &space_info);
5171                 BUG_ON(ret);
5172                 cache->space_info = space_info;
5173                 down_write(&space_info->groups_sem);
5174                 list_add_tail(&cache->list, &space_info->block_groups);
5175                 up_write(&space_info->groups_sem);
5176
5177                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
5178                 BUG_ON(ret);
5179
5180                 set_avail_alloc_bits(root->fs_info, cache->flags);
5181         }
5182         ret = 0;
5183 error:
5184         btrfs_free_path(path);
5185         return ret;
5186 }
5187
5188 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
5189                            struct btrfs_root *root, u64 bytes_used,
5190                            u64 type, u64 chunk_objectid, u64 chunk_offset,
5191                            u64 size)
5192 {
5193         int ret;
5194         struct btrfs_root *extent_root;
5195         struct btrfs_block_group_cache *cache;
5196
5197         extent_root = root->fs_info->extent_root;
5198
5199         root->fs_info->last_trans_new_blockgroup = trans->transid;
5200
5201         cache = kzalloc(sizeof(*cache), GFP_NOFS);
5202         if (!cache)
5203                 return -ENOMEM;
5204
5205         cache->key.objectid = chunk_offset;
5206         cache->key.offset = size;
5207         spin_lock_init(&cache->lock);
5208         mutex_init(&cache->alloc_mutex);
5209         INIT_LIST_HEAD(&cache->list);
5210         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
5211
5212         btrfs_set_block_group_used(&cache->item, bytes_used);
5213         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
5214         cache->flags = type;
5215         btrfs_set_block_group_flags(&cache->item, type);
5216
5217         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
5218                                 &cache->space_info);
5219         BUG_ON(ret);
5220         down_write(&cache->space_info->groups_sem);
5221         list_add_tail(&cache->list, &cache->space_info->block_groups);
5222         up_write(&cache->space_info->groups_sem);
5223
5224         ret = btrfs_add_block_group_cache(root->fs_info, cache);
5225         BUG_ON(ret);
5226
5227         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
5228                                 sizeof(cache->item));
5229         BUG_ON(ret);
5230
5231         finish_current_insert(trans, extent_root);
5232         ret = del_pending_extents(trans, extent_root);
5233         BUG_ON(ret);
5234         set_avail_alloc_bits(extent_root->fs_info, type);
5235
5236         return 0;
5237 }
5238
5239 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
5240                              struct btrfs_root *root, u64 group_start)
5241 {
5242         struct btrfs_path *path;
5243         struct btrfs_block_group_cache *block_group;
5244         struct btrfs_key key;
5245         int ret;
5246
5247         root = root->fs_info->extent_root;
5248
5249         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
5250         BUG_ON(!block_group);
5251
5252         memcpy(&key, &block_group->key, sizeof(key));
5253
5254         path = btrfs_alloc_path();
5255         BUG_ON(!path);
5256
5257         btrfs_remove_free_space_cache(block_group);
5258         rb_erase(&block_group->cache_node,
5259                  &root->fs_info->block_group_cache_tree);
5260         down_write(&block_group->space_info->groups_sem);
5261         list_del(&block_group->list);
5262         up_write(&block_group->space_info->groups_sem);
5263
5264         /*
5265         memset(shrink_block_group, 0, sizeof(*shrink_block_group));
5266         kfree(shrink_block_group);
5267         */
5268
5269         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
5270         if (ret > 0)
5271                 ret = -EIO;
5272         if (ret < 0)
5273                 goto out;
5274
5275         ret = btrfs_del_item(trans, root, path);
5276 out:
5277         btrfs_free_path(path);
5278         return ret;
5279 }