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
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include "kerncompat.h"
  22 #include "radix-tree.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "print-tree.h"
  26 #include "transaction.h"
  27 #include "crc32c.h"
  28 #include "volumes.h"
  29
  30 #define BLOCK_GROUP_DATA     EXTENT_WRITEBACK
  31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
  32 #define BLOCK_GROUP_SYSTEM   EXTENT_NEW
  33
  34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
  35
  36 #define PENDING_EXTENT_INSERT 0
  37 #define PENDING_EXTENT_DELETE 1
  38 #define PENDING_BACKREF_UPDATE 2
  39
  40 struct pending_extent_op {
  41         int type;
  42         u64 bytenr;
  43         u64 num_bytes;
  44         u64 flags;
  45         struct btrfs_disk_key key;
  46         int level;
  47 };
  48
  49 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  50                                      struct btrfs_root *root,
  51                                      u64 root_objectid, u64 generation,
  52                                      u64 flags, struct btrfs_disk_key *key,
  53                                      int level, struct btrfs_key *ins);
  54 static int __free_extent(struct btrfs_trans_handle *trans,
  55                          struct btrfs_root *root,
  56                          u64 bytenr, u64 num_bytes, u64 parent,
  57                          u64 root_objectid, u64 owner_objectid,
  58                          u64 owner_offset, int refs_to_drop);
  59 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  60                                  btrfs_root *extent_root);
  61 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  62                                btrfs_root *extent_root);
  63
  64 static int remove_sb_from_cache(struct btrfs_root *root,
  65                                 struct btrfs_block_group_cache *cache)
  66 {
  67         u64 bytenr;
  68         u64 *logical;
  69         int stripe_len;
  70         int i, nr, ret;
  71         struct extent_io_tree *free_space_cache;
  72
  73         free_space_cache = &root->fs_info->free_space_cache;
  74         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
  75                 bytenr = btrfs_sb_offset(i);
  76                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
  77                                        cache->key.objectid, bytenr, 0,
  78                                        &logical, &nr, &stripe_len);
  79                 BUG_ON(ret);
  80                 while (nr--) {
  81                         clear_extent_dirty(free_space_cache, logical[nr],
  82                                 logical[nr] + stripe_len - 1, GFP_NOFS);
  83                 }
  84                 kfree(logical);
  85         }
  86         return 0;
  87 }
  88
  89 static int cache_block_group(struct btrfs_root *root,
  90                              struct btrfs_block_group_cache *block_group)
  91 {
  92         struct btrfs_path *path;
  93         int ret;
  94         struct btrfs_key key;
  95         struct extent_buffer *leaf;
  96         struct extent_io_tree *free_space_cache;
  97         int slot;
  98         u64 last;
  99         u64 hole_size;
 100
 101         if (!block_group)
 102                 return 0;
 103
 104         root = root->fs_info->extent_root;
 105         free_space_cache = &root->fs_info->free_space_cache;
 106
 107         if (block_group->cached)
 108                 return 0;
 109
 110         path = btrfs_alloc_path();
 111         if (!path)
 112                 return -ENOMEM;
 113
 114         path->reada = 2;
 115         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 116         key.objectid = last;
 117         key.offset = 0;
 118         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 119         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 120         if (ret < 0)
 121                 goto err;
 122
 123         while(1) {
 124                 leaf = path->nodes[0];
 125                 slot = path->slots[0];
 126                 if (slot >= btrfs_header_nritems(leaf)) {
 127                         ret = btrfs_next_leaf(root, path);
 128                         if (ret < 0)
 129                                 goto err;
 130                         if (ret == 0) {
 131                                 continue;
 132                         } else {
 133                                 break;
 134                         }
 135                 }
 136                 btrfs_item_key_to_cpu(leaf, &key, slot);
 137                 if (key.objectid < block_group->key.objectid) {
 138                         goto next;
 139                 }
 140                 if (key.objectid >= block_group->key.objectid +
 141                     block_group->key.offset) {
 142                         break;
 143                 }
 144
 145                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 146                         if (key.objectid > last) {
 147                                 hole_size = key.objectid - last;
 148                                 set_extent_dirty(free_space_cache, last,
 149                                                  last + hole_size - 1,
 150                                                  GFP_NOFS);
 151                         }
 152                         last = key.objectid + key.offset;
 153                 }
 154 next:
 155                 path->slots[0]++;
 156         }
 157
 158         if (block_group->key.objectid +
 159             block_group->key.offset > last) {
 160                 hole_size = block_group->key.objectid +
 161                         block_group->key.offset - last;
 162                 set_extent_dirty(free_space_cache, last,
 163                                  last + hole_size - 1, GFP_NOFS);
 164         }
 165         remove_sb_from_cache(root, block_group);
 166         block_group->cached = 1;
 167 err:
 168         btrfs_free_path(path);
 169         return 0;
 170 }
 171
 172 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
 173                                                        btrfs_fs_info *info,
 174                                                        u64 bytenr)
 175 {
 176         struct extent_io_tree *block_group_cache;
 177         struct btrfs_block_group_cache *block_group = NULL;
 178         u64 ptr;
 179         u64 start;
 180         u64 end;
 181         int ret;
 182
 183         bytenr = max_t(u64, bytenr,
 184                        BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 185         block_group_cache = &info->block_group_cache;
 186         ret = find_first_extent_bit(block_group_cache,
 187                                     bytenr, &start, &end,
 188                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 189                                     BLOCK_GROUP_SYSTEM);
 190         if (ret) {
 191                 return NULL;
 192         }
 193         ret = get_state_private(block_group_cache, start, &ptr);
 194         if (ret)
 195                 return NULL;
 196
 197         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 198         return block_group;
 199 }
 200
 201 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 202                                                          btrfs_fs_info *info,
 203                                                          u64 bytenr)
 204 {
 205         struct extent_io_tree *block_group_cache;
 206         struct btrfs_block_group_cache *block_group = NULL;
 207         u64 ptr;
 208         u64 start;
 209         u64 end;
 210         int ret;
 211
 212         block_group_cache = &info->block_group_cache;
 213         ret = find_first_extent_bit(block_group_cache,
 214                                     bytenr, &start, &end,
 215                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 216                                     BLOCK_GROUP_SYSTEM);
 217         if (ret) {
 218                 return NULL;
 219         }
 220         ret = get_state_private(block_group_cache, start, &ptr);
 221         if (ret)
 222                 return NULL;
 223
 224         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 225         if (block_group->key.objectid <= bytenr && bytenr <
 226             block_group->key.objectid + block_group->key.offset)
 227                 return block_group;
 228         return NULL;
 229 }
 230
 231 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 232 {
 233         return (cache->flags & bits) == bits;
 234 }
 235
 236 static int noinline find_search_start(struct btrfs_root *root,
 237                               struct btrfs_block_group_cache **cache_ret,
 238                               u64 *start_ret, int num, int data)
 239 {
 240         int ret;
 241         struct btrfs_block_group_cache *cache = *cache_ret;
 242         u64 last;
 243         u64 start = 0;
 244         u64 end = 0;
 245         u64 search_start = *start_ret;
 246         int wrapped = 0;
 247
 248         if (!cache) {
 249                 goto out;
 250         }
 251 again:
 252         ret = cache_block_group(root, cache);
 253         if (ret)
 254                 goto out;
 255
 256         last = max(search_start, cache->key.objectid);
 257         if (cache->ro || !block_group_bits(cache, data)) {
 258                 goto new_group;
 259         }
 260
 261         while(1) {
 262                 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
 263                                             last, &start, &end, EXTENT_DIRTY);
 264                 if (ret) {
 265                         goto new_group;
 266                 }
 267
 268                 start = max(last, start);
 269                 last = end + 1;
 270                 if (last - start < num) {
 271                         continue;
 272                 }
 273                 if (start + num > cache->key.objectid + cache->key.offset) {
 274                         goto new_group;
 275                 }
 276                 *start_ret = start;
 277                 return 0;
 278         }
 279 out:
 280         cache = btrfs_lookup_block_group(root->fs_info, search_start);
 281         if (!cache) {
 282                 printk("Unable to find block group for %llu\n",
 283                         (unsigned long long)search_start);
 284                 WARN_ON(1);
 285         }
 286         return -ENOSPC;
 287
 288 new_group:
 289         last = cache->key.objectid + cache->key.offset;
 290 wrapped:
 291         cache = btrfs_lookup_first_block_group(root->fs_info, last);
 292         if (!cache) {
 293 no_cache:
 294                 if (!wrapped) {
 295                         wrapped = 1;
 296                         last = search_start;
 297                         goto wrapped;
 298                 }
 299                 goto out;
 300         }
 301         cache = btrfs_find_block_group(root, cache, last, data, 0);
 302         cache = btrfs_find_block_group(root, cache, last, data, 0);
 303         if (!cache)
 304                 goto no_cache;
 305
 306         *cache_ret = cache;
 307         goto again;
 308 }
 309
 310 static u64 div_factor(u64 num, int factor)
 311 {
 312         if (factor == 10)
 313                 return num;
 314         num *= factor;
 315         num /= 10;
 316         return num;
 317 }
 318
 319 static int block_group_state_bits(u64 flags)
 320 {
 321         int bits = 0;
 322         if (flags & BTRFS_BLOCK_GROUP_DATA)
 323                 bits |= BLOCK_GROUP_DATA;
 324         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 325                 bits |= BLOCK_GROUP_METADATA;
 326         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 327                 bits |= BLOCK_GROUP_SYSTEM;
 328         return bits;
 329 }
 330
 331 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 332                                                  struct btrfs_block_group_cache
 333                                                  *hint, u64 search_start,
 334                                                  int data, int owner)
 335 {
 336         struct btrfs_block_group_cache *cache;
 337         struct extent_io_tree *block_group_cache;
 338         struct btrfs_block_group_cache *found_group = NULL;
 339         struct btrfs_fs_info *info = root->fs_info;
 340         u64 used;
 341         u64 last = 0;
 342         u64 hint_last;
 343         u64 start;
 344         u64 end;
 345         u64 free_check;
 346         u64 ptr;
 347         int bit;
 348         int ret;
 349         int full_search = 0;
 350         int factor = 10;
 351
 352         block_group_cache = &info->block_group_cache;
 353
 354         if (!owner)
 355                 factor = 10;
 356
 357         bit = block_group_state_bits(data);
 358
 359         if (search_start) {
 360                 struct btrfs_block_group_cache *shint;
 361                 shint = btrfs_lookup_block_group(info, search_start);
 362                 if (shint && !shint->ro && block_group_bits(shint, data)) {
 363                         used = btrfs_block_group_used(&shint->item);
 364                         if (used + shint->pinned <
 365                             div_factor(shint->key.offset, factor)) {
 366                                 return shint;
 367                         }
 368                 }
 369         }
 370         if (hint && !hint->ro && block_group_bits(hint, data)) {
 371                 used = btrfs_block_group_used(&hint->item);
 372                 if (used + hint->pinned <
 373                     div_factor(hint->key.offset, factor)) {
 374                         return hint;
 375                 }
 376                 last = hint->key.objectid + hint->key.offset;
 377                 hint_last = last;
 378         } else {
 379                 if (hint)
 380                         hint_last = max(hint->key.objectid, search_start);
 381                 else
 382                         hint_last = search_start;
 383
 384                 last = hint_last;
 385         }
 386 again:
 387         while(1) {
 388                 ret = find_first_extent_bit(block_group_cache, last,
 389                                             &start, &end, bit);
 390                 if (ret)
 391                         break;
 392
 393                 ret = get_state_private(block_group_cache, start, &ptr);
 394                 if (ret)
 395                         break;
 396
 397                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 398                 last = cache->key.objectid + cache->key.offset;
 399                 used = btrfs_block_group_used(&cache->item);
 400
 401                 if (!cache->ro && block_group_bits(cache, data)) {
 402                         if (full_search)
 403                                 free_check = cache->key.offset;
 404                         else
 405                                 free_check = div_factor(cache->key.offset,
 406                                                         factor);
 407
 408                         if (used + cache->pinned < free_check) {
 409                                 found_group = cache;
 410                                 goto found;
 411                         }
 412                 }
 413                 cond_resched();
 414         }
 415         if (!full_search) {
 416                 last = search_start;
 417                 full_search = 1;
 418                 goto again;
 419         }
 420 found:
 421         return found_group;
 422 }
 423
 424 /*
 425  * Back reference rules.  Back refs have three main goals:
 426  *
 427  * 1) differentiate between all holders of references to an extent so that
 428  *    when a reference is dropped we can make sure it was a valid reference
 429  *    before freeing the extent.
 430  *
 431  * 2) Provide enough information to quickly find the holders of an extent
 432  *    if we notice a given block is corrupted or bad.
 433  *
 434  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 435  *    maintenance.  This is actually the same as #2, but with a slightly
 436  *    different use case.
 437  *
 438  * There are two kinds of back refs. The implicit back refs is optimized
 439  * for pointers in non-shared tree blocks. For a given pointer in a block,
 440  * back refs of this kind provide information about the block's owner tree
 441  * and the pointer's key. These information allow us to find the block by
 442  * b-tree searching. The full back refs is for pointers in tree blocks not
 443  * referenced by their owner trees. The location of tree block is recorded
 444  * in the back refs. Actually the full back refs is generic, and can be
 445  * used in all cases the implicit back refs is used. The major shortcoming
 446  * of the full back refs is its overhead. Every time a tree block gets
 447  * COWed, we have to update back refs entry for all pointers in it.
 448  *
 449  * For a newly allocated tree block, we use implicit back refs for
 450  * pointers in it. This means most tree related operations only involve
 451  * implicit back refs. For a tree block created in old transaction, the
 452  * only way to drop a reference to it is COW it. So we can detect the
 453  * event that tree block loses its owner tree's reference and do the
 454  * back refs conversion.
 455  *
 456  * When a tree block is COW'd through a tree, there are four cases:
 457  *
 458  * The reference count of the block is one and the tree is the block's
 459  * owner tree. Nothing to do in this case.
 460  *
 461  * The reference count of the block is one and the tree is not the
 462  * block's owner tree. In this case, full back refs is used for pointers
 463  * in the block. Remove these full back refs, add implicit back refs for
 464  * every pointers in the new block.
 465  *
 466  * The reference count of the block is greater than one and the tree is
 467  * the block's owner tree. In this case, implicit back refs is used for
 468  * pointers in the block. Add full back refs for every pointers in the
 469  * block, increase lower level extents' reference counts. The original
 470  * implicit back refs are entailed to the new block.
 471  *
 472  * The reference count of the block is greater than one and the tree is
 473  * not the block's owner tree. Add implicit back refs for every pointer in
 474  * the new block, increase lower level extents' reference count.
 475  *
 476  * Back Reference Key composing:
 477  *
 478  * The key objectid corresponds to the first byte in the extent,
 479  * The key type is used to differentiate between types of back refs.
 480  * There are different meanings of the key offset for different types
 481  * of back refs.
 482  *
 483  * File extents can be referenced by:
 484  *
 485  * - multiple snapshots, subvolumes, or different generations in one subvol
 486  * - different files inside a single subvolume
 487  * - different offsets inside a file (bookend extents in file.c)
 488  *
 489  * The extent ref structure for the implicit back refs has fields for:
 490  *
 491  * - Objectid of the subvolume root
 492  * - objectid of the file holding the reference
 493  * - original offset in the file
 494  * - how many bookend extents
 495  *
 496  * The key offset for the implicit back refs is hash of the first
 497  * three fields.
 498  *
 499  * The extent ref structure for the full back refs has field for:
 500  *
 501  * - number of pointers in the tree leaf
 502  *
 503  * The key offset for the implicit back refs is the first byte of
 504  * the tree leaf
 505  *
 506  * When a file extent is allocated, The implicit back refs is used.
 507  * the fields are filled in:
 508  *
 509  *     (root_key.objectid, inode objectid, offset in file, 1)
 510  *
 511  * When a file extent is removed file truncation, we find the
 512  * corresponding implicit back refs and check the following fields:
 513  *
 514  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 515  *
 516  * Btree extents can be referenced by:
 517  *
 518  * - Different subvolumes
 519  *
 520  * Both the implicit back refs and the full back refs for tree blocks
 521  * only consist of key. The key offset for the implicit back refs is
 522  * objectid of block's owner tree. The key offset for the full back refs
 523  * is the first byte of parent block.
 524  *
 525  * When implicit back refs is used, information about the lowest key and
 526  * level of the tree block are required. These information are stored in
 527  * tree block info structure.
 528  */
 529
 530 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 531 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 532                                   struct btrfs_root *root,
 533                                   struct btrfs_path *path,
 534                                   u64 owner, u32 extra_size)
 535 {
 536         struct btrfs_extent_item *item;
 537         struct btrfs_extent_item_v0 *ei0;
 538         struct btrfs_extent_ref_v0 *ref0;
 539         struct btrfs_tree_block_info *bi;
 540         struct extent_buffer *leaf;
 541         struct btrfs_key key;
 542         struct btrfs_key found_key;
 543         u32 new_size = sizeof(*item);
 544         u64 refs;
 545         int ret;
 546
 547         leaf = path->nodes[0];
 548         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 549
 550         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 551         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 552                              struct btrfs_extent_item_v0);
 553         refs = btrfs_extent_refs_v0(leaf, ei0);
 554
 555         if (owner == (u64)-1) {
 556                 while (1) {
 557                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 558                                 ret = btrfs_next_leaf(root, path);
 559                                 if (ret < 0)
 560                                         return ret;
 561                                 BUG_ON(ret > 0);
 562                                 leaf = path->nodes[0];
 563                         }
 564                         btrfs_item_key_to_cpu(leaf, &found_key,
 565                                               path->slots[0]);
 566                         BUG_ON(key.objectid != found_key.objectid);
 567                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 568                                 path->slots[0]++;
 569                                 continue;
 570                         }
 571                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 572                                               struct btrfs_extent_ref_v0);
 573                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 574                         break;
 575                 }
 576         }
 577         btrfs_release_path(root, path);
 578
 579         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 580                 new_size += sizeof(*bi);
 581
 582         new_size -= sizeof(*ei0);
 583         ret = btrfs_search_slot(trans, root, &key, path, new_size, 1);
 584         if (ret < 0)
 585                 return ret;
 586         BUG_ON(ret);
 587
 588         ret = btrfs_extend_item(trans, root, path, new_size);
 589         BUG_ON(ret);
 590
 591         leaf = path->nodes[0];
 592         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 593         btrfs_set_extent_refs(leaf, item, refs);
 594         /* FIXME: get real generation */
 595         btrfs_set_extent_generation(leaf, item, 0);
 596         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 597                 btrfs_set_extent_flags(leaf, item,
 598                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 599                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 600                 bi = (struct btrfs_tree_block_info *)(item + 1);
 601                 /* FIXME: get first key of the block */
 602                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 603                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 604         } else {
 605                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 606         }
 607         btrfs_mark_buffer_dirty(leaf);
 608         return 0;
 609 }
 610 #endif
 611
 612 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 613 {
 614         u32 high_crc = ~(u32)0;
 615         u32 low_crc = ~(u32)0;
 616         __le64 lenum;
 617
 618         lenum = cpu_to_le64(root_objectid);
 619         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 620         lenum = cpu_to_le64(owner);
 621         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 622         lenum = cpu_to_le64(offset);
 623         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 624
 625         return ((u64)high_crc << 31) ^ (u64)low_crc;
 626 }
 627
 628 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 629                                      struct btrfs_extent_data_ref *ref)
 630 {
 631         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 632                                     btrfs_extent_data_ref_objectid(leaf, ref),
 633                                     btrfs_extent_data_ref_offset(leaf, ref));
 634 }
 635
 636 static int match_extent_data_ref(struct extent_buffer *leaf,
 637                                  struct btrfs_extent_data_ref *ref,
 638                                  u64 root_objectid, u64 owner, u64 offset)
 639 {
 640         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 641             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 642             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 643                 return 0;
 644         return 1;
 645 }
 646
 647 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 648                                            struct btrfs_root *root,
 649                                            struct btrfs_path *path,
 650                                            u64 bytenr, u64 parent,
 651                                            u64 root_objectid,
 652                                            u64 owner, u64 offset)
 653 {
 654         struct btrfs_key key;
 655         struct btrfs_extent_data_ref *ref;
 656         struct extent_buffer *leaf;
 657         u32 nritems;
 658         int ret;
 659         int recow;
 660         int err = -ENOENT;
 661
 662         key.objectid = bytenr;
 663         if (parent) {
 664                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 665                 key.offset = parent;
 666         } else {
 667                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 668                 key.offset = hash_extent_data_ref(root_objectid,
 669                                                   owner, offset);
 670         }
 671 again:
 672         recow = 0;
 673         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 674         if (ret < 0) {
 675                 err = ret;
 676                 goto fail;
 677         }
 678
 679         if (parent) {
 680                 if (!ret)
 681                         return 0;
 682 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 683                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 684                 btrfs_release_path(root, path);
 685                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 686                 if (ret < 0) {
 687                         err = ret;
 688                         goto fail;
 689                 }
 690                 if (!ret)
 691                         return 0;
 692 #endif
 693                 goto fail;
 694         }
 695
 696         leaf = path->nodes[0];
 697         nritems = btrfs_header_nritems(leaf);
 698         while (1) {
 699                 if (path->slots[0] >= nritems) {
 700                         ret = btrfs_next_leaf(root, path);
 701                         if (ret < 0)
 702                                 err = ret;
 703                         if (ret)
 704                                 goto fail;
 705
 706                         leaf = path->nodes[0];
 707                         nritems = btrfs_header_nritems(leaf);
 708                         recow = 1;
 709                 }
 710
 711                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 712                 if (key.objectid != bytenr ||
 713                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 714                         goto fail;
 715
 716                 ref = btrfs_item_ptr(leaf, path->slots[0],
 717                                      struct btrfs_extent_data_ref);
 718
 719                 if (match_extent_data_ref(leaf, ref, root_objectid,
 720                                           owner, offset)) {
 721                         if (recow) {
 722                                 btrfs_release_path(root, path);
 723                                 goto again;
 724                         }
 725                         err = 0;
 726                         break;
 727                 }
 728                 path->slots[0]++;
 729         }
 730 fail:
 731         return err;
 732 }
 733
 734 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 735                                            struct btrfs_root *root,
 736                                            struct btrfs_path *path,
 737                                            u64 bytenr, u64 parent,
 738                                            u64 root_objectid, u64 owner,
 739                                            u64 offset, int refs_to_add)
 740 {
 741         struct btrfs_key key;
 742         struct extent_buffer *leaf;
 743         u32 size;
 744         u32 num_refs;
 745         int ret;
 746
 747         key.objectid = bytenr;
 748         if (parent) {
 749                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 750                 key.offset = parent;
 751                 size = sizeof(struct btrfs_shared_data_ref);
 752         } else {
 753                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 754                 key.offset = hash_extent_data_ref(root_objectid,
 755                                                   owner, offset);
 756                 size = sizeof(struct btrfs_extent_data_ref);
 757         }
 758
 759         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 760         if (ret && ret != -EEXIST)
 761                 goto fail;
 762
 763         leaf = path->nodes[0];
 764         if (parent) {
 765                 struct btrfs_shared_data_ref *ref;
 766                 ref = btrfs_item_ptr(leaf, path->slots[0],
 767                                      struct btrfs_shared_data_ref);
 768                 if (ret == 0) {
 769                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 770                 } else {
 771                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 772                         num_refs += refs_to_add;
 773                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 774                 }
 775         } else {
 776                 struct btrfs_extent_data_ref *ref;
 777                 while (ret == -EEXIST) {
 778                         ref = btrfs_item_ptr(leaf, path->slots[0],
 779                                              struct btrfs_extent_data_ref);
 780                         if (match_extent_data_ref(leaf, ref, root_objectid,
 781                                                   owner, offset))
 782                                 break;
 783                         btrfs_release_path(root, path);
 784
 785                         key.offset++;
 786                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 787                                                       size);
 788                         if (ret && ret != -EEXIST)
 789                                 goto fail;
 790
 791                         leaf = path->nodes[0];
 792                 }
 793                 ref = btrfs_item_ptr(leaf, path->slots[0],
 794                                      struct btrfs_extent_data_ref);
 795                 if (ret == 0) {
 796                         btrfs_set_extent_data_ref_root(leaf, ref,
 797                                                        root_objectid);
 798                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 799                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 800                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 801                 } else {
 802                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 803                         num_refs += refs_to_add;
 804                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 805                 }
 806         }
 807         btrfs_mark_buffer_dirty(leaf);
 808         ret = 0;
 809 fail:
 810         btrfs_release_path(root, path);
 811         return ret;
 812 }
 813
 814 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 815                                            struct btrfs_root *root,
 816                                            struct btrfs_path *path,
 817                                            int refs_to_drop)
 818 {
 819         struct btrfs_key key;
 820         struct btrfs_extent_data_ref *ref1 = NULL;
 821         struct btrfs_shared_data_ref *ref2 = NULL;
 822         struct extent_buffer *leaf;
 823         u32 num_refs = 0;
 824         int ret = 0;
 825
 826         leaf = path->nodes[0];
 827         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 828
 829         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 830                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 831                                       struct btrfs_extent_data_ref);
 832                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 833         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 834                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 835                                       struct btrfs_shared_data_ref);
 836                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 837 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 838         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 839                 struct btrfs_extent_ref_v0 *ref0;
 840                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 841                                       struct btrfs_extent_ref_v0);
 842                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 843 #endif
 844         } else {
 845                 BUG();
 846         }
 847
 848         BUG_ON(num_refs < refs_to_drop);
 849         num_refs -= refs_to_drop;
 850
 851         if (num_refs == 0) {
 852                 ret = btrfs_del_item(trans, root, path);
 853         } else {
 854                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 855                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 856                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 857                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 858 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 859                 else {
 860                         struct btrfs_extent_ref_v0 *ref0;
 861                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 862                                         struct btrfs_extent_ref_v0);
 863                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
 864                 }
 865 #endif
 866                 btrfs_mark_buffer_dirty(leaf);
 867         }
 868         return ret;
 869 }
 870
 871 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
 872                                           struct btrfs_path *path,
 873                                           struct btrfs_extent_inline_ref *iref)
 874 {
 875         struct btrfs_key key;
 876         struct extent_buffer *leaf;
 877         struct btrfs_extent_data_ref *ref1;
 878         struct btrfs_shared_data_ref *ref2;
 879         u32 num_refs = 0;
 880
 881         leaf = path->nodes[0];
 882         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 883         if (iref) {
 884                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
 885                     BTRFS_EXTENT_DATA_REF_KEY) {
 886                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 887                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 888                 } else {
 889                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 890                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 891                 }
 892         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 893                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 894                                       struct btrfs_extent_data_ref);
 895                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 896         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 897                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 898                                       struct btrfs_shared_data_ref);
 899                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 900 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 901         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 902                 struct btrfs_extent_ref_v0 *ref0;
 903                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 904                                       struct btrfs_extent_ref_v0);
 905                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 906 #endif
 907         } else {
 908                 BUG();
 909         }
 910         return num_refs;
 911 }
 912
 913 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 914                                           struct btrfs_root *root,
 915                                           struct btrfs_path *path,
 916                                           u64 bytenr, u64 parent,
 917                                           u64 root_objectid)
 918 {
 919         struct btrfs_key key;
 920         int ret;
 921
 922         key.objectid = bytenr;
 923         if (parent) {
 924                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 925                 key.offset = parent;
 926         } else {
 927                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 928                 key.offset = root_objectid;
 929         }
 930
 931         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 932         if (ret > 0)
 933                 ret = -ENOENT;
 934 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 935         if (ret == -ENOENT && parent) {
 936                 btrfs_release_path(root, path);
 937                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 938                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 939                 if (ret > 0)
 940                         ret = -ENOENT;
 941         }
 942 #endif
 943         return ret;
 944 }
 945
 946 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 947                                           struct btrfs_root *root,
 948                                           struct btrfs_path *path,
 949                                           u64 bytenr, u64 parent,
 950                                           u64 root_objectid)
 951 {
 952         struct btrfs_key key;
 953         int ret;
 954
 955         key.objectid = bytenr;
 956         if (parent) {
 957                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 958                 key.offset = parent;
 959         } else {
 960                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 961                 key.offset = root_objectid;
 962         }
 963
 964         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
 965
 966         btrfs_release_path(root, path);
 967         return ret;
 968 }
 969
 970 static inline int extent_ref_type(u64 parent, u64 owner)
 971 {
 972         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 973                 if (parent > 0)
 974                         return BTRFS_SHARED_BLOCK_REF_KEY;
 975                 else
 976                         return BTRFS_TREE_BLOCK_REF_KEY;
 977         } else {
 978                 if (parent > 0)
 979                         return BTRFS_SHARED_DATA_REF_KEY;
 980                 else
 981                         return BTRFS_EXTENT_DATA_REF_KEY;
 982         }
 983 }
 984
 985 static int find_next_key(struct btrfs_path *path, struct btrfs_key *key)
 986
 987 {
 988         int level;
 989         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
 990                 if (!path->nodes[level])
 991                         break;
 992                 if (path->slots[level] + 1 >=
 993                     btrfs_header_nritems(path->nodes[level]))
 994                         continue;
 995                 if (level == 0)
 996                         btrfs_item_key_to_cpu(path->nodes[level], key,
 997                                               path->slots[level] + 1);
 998                 else
 999                         btrfs_node_key_to_cpu(path->nodes[level], key,
1000                                               path->slots[level] + 1);
1001                 return 0;
1002         }
1003         return 1;
1004 }
1005
1006 static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1007                                  struct btrfs_root *root,
1008                                  struct btrfs_path *path,
1009                                  struct btrfs_extent_inline_ref **ref_ret,
1010                                  u64 bytenr, u64 num_bytes,
1011                                  u64 parent, u64 root_objectid,
1012                                  u64 owner, u64 offset, int insert)
1013 {
1014         struct btrfs_key key;
1015         struct extent_buffer *leaf;
1016         struct btrfs_extent_item *ei;
1017         struct btrfs_extent_inline_ref *iref;
1018         u64 flags;
1019         u32 item_size;
1020         unsigned long ptr;
1021         unsigned long end;
1022         int extra_size;
1023         int type;
1024         int want;
1025         int ret;
1026         int err = 0;
1027
1028         key.objectid = bytenr;
1029         key.type = BTRFS_EXTENT_ITEM_KEY;
1030         key.offset = num_bytes;
1031
1032         want = extent_ref_type(parent, owner);
1033         if (insert)
1034                 extra_size = btrfs_extent_inline_ref_size(want);
1035         else
1036                 extra_size = -1;
1037         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1038         if (ret < 0) {
1039                 err = ret;
1040                 goto out;
1041         }
1042         if (ret) {
1043                 printf("Failed to find [%llu, %u, %llu]\n", key.objectid, key.type, key.offset);
1044                 return -ENOENT;
1045         }
1046
1047         BUG_ON(ret);
1048
1049         leaf = path->nodes[0];
1050         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1051 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1052         if (item_size < sizeof(*ei)) {
1053                 if (!insert) {
1054                         err = -ENOENT;
1055                         goto out;
1056                 }
1057                 ret = convert_extent_item_v0(trans, root, path, owner,
1058                                              extra_size);
1059                 if (ret < 0) {
1060                         err = ret;
1061                         goto out;
1062                 }
1063                 leaf = path->nodes[0];
1064                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1065         }
1066 #endif
1067         if (item_size < sizeof(*ei)) {
1068                 printf("Size is %u, needs to be %u, slot %d\n",
1069                        (unsigned)item_size,
1070                        (unsigned)sizeof(*ei), path->slots[0]);
1071                 btrfs_print_leaf(root, leaf);
1072                 return -EINVAL;
1073         }
1074         BUG_ON(item_size < sizeof(*ei));
1075
1076         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1077         flags = btrfs_extent_flags(leaf, ei);
1078
1079         ptr = (unsigned long)(ei + 1);
1080         end = (unsigned long)ei + item_size;
1081
1082         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1083                 ptr += sizeof(struct btrfs_tree_block_info);
1084                 BUG_ON(ptr > end);
1085         } else {
1086                 if (!(flags & BTRFS_EXTENT_FLAG_DATA)) {
1087                         return -EIO;
1088                 }
1089         }
1090
1091         err = -ENOENT;
1092         while (1) {
1093                 if (ptr >= end) {
1094                         WARN_ON(ptr > end);
1095                         break;
1096                 }
1097                 iref = (struct btrfs_extent_inline_ref *)ptr;
1098                 type = btrfs_extent_inline_ref_type(leaf, iref);
1099                 if (want < type)
1100                         break;
1101                 if (want > type) {
1102                         ptr += btrfs_extent_inline_ref_size(type);
1103                         continue;
1104                 }
1105
1106                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1107                         struct btrfs_extent_data_ref *dref;
1108                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1109                         if (match_extent_data_ref(leaf, dref, root_objectid,
1110                                                   owner, offset)) {
1111                                 err = 0;
1112                                 break;
1113                         }
1114                         if (hash_extent_data_ref_item(leaf, dref) <
1115                             hash_extent_data_ref(root_objectid, owner, offset))
1116                                 break;
1117                 } else {
1118                         u64 ref_offset;
1119                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1120                         if (parent > 0) {
1121                                 if (parent == ref_offset) {
1122                                         err = 0;
1123                                         break;
1124                                 }
1125                                 if (ref_offset < parent)
1126                                         break;
1127                         } else {
1128                                 if (root_objectid == ref_offset) {
1129                                         err = 0;
1130                                         break;
1131                                 }
1132                                 if (ref_offset < root_objectid)
1133                                         break;
1134                         }
1135                 }
1136                 ptr += btrfs_extent_inline_ref_size(type);
1137         }
1138         if (err == -ENOENT && insert) {
1139                 if (item_size + extra_size >=
1140                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1141                         err = -EAGAIN;
1142                         goto out;
1143                 }
1144                 /*
1145                  * To add new inline back ref, we have to make sure
1146                  * there is no corresponding back ref item.
1147                  * For simplicity, we just do not add new inline back
1148                  * ref if there is any back ref item.
1149                  */
1150                 if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&
1151                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1152                         err = -EAGAIN;
1153                         goto out;
1154                 }
1155         }
1156         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1157 out:
1158         return err;
1159 }
1160
1161 static int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1162                                 struct btrfs_root *root,
1163                                 struct btrfs_path *path,
1164                                 struct btrfs_extent_inline_ref *iref,
1165                                 u64 parent, u64 root_objectid,
1166                                 u64 owner, u64 offset, int refs_to_add)
1167 {
1168         struct extent_buffer *leaf;
1169         struct btrfs_extent_item *ei;
1170         unsigned long ptr;
1171         unsigned long end;
1172         unsigned long item_offset;
1173         u64 refs;
1174         int size;
1175         int type;
1176         int ret;
1177
1178         leaf = path->nodes[0];
1179         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1180         item_offset = (unsigned long)iref - (unsigned long)ei;
1181
1182         type = extent_ref_type(parent, owner);
1183         size = btrfs_extent_inline_ref_size(type);
1184
1185         ret = btrfs_extend_item(trans, root, path, size);
1186         BUG_ON(ret);
1187
1188         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1189         refs = btrfs_extent_refs(leaf, ei);
1190         refs += refs_to_add;
1191         btrfs_set_extent_refs(leaf, ei, refs);
1192
1193         ptr = (unsigned long)ei + item_offset;
1194         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1195         if (ptr < end - size)
1196                 memmove_extent_buffer(leaf, ptr + size, ptr,
1197                                       end - size - ptr);
1198
1199         iref = (struct btrfs_extent_inline_ref *)ptr;
1200         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1201         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1202                 struct btrfs_extent_data_ref *dref;
1203                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1204                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1205                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1206                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1207                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1208         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1209                 struct btrfs_shared_data_ref *sref;
1210                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1211                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1212                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1213         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1214                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1215         } else {
1216                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1217         }
1218         btrfs_mark_buffer_dirty(leaf);
1219         return 0;
1220 }
1221
1222 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1223                                  struct btrfs_root *root,
1224                                  struct btrfs_path *path,
1225                                  struct btrfs_extent_inline_ref **ref_ret,
1226                                  u64 bytenr, u64 num_bytes, u64 parent,
1227                                  u64 root_objectid, u64 owner, u64 offset)
1228 {
1229         int ret;
1230
1231         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1232                                            bytenr, num_bytes, parent,
1233                                            root_objectid, owner, offset, 0);
1234         if (ret != -ENOENT)
1235                 return ret;
1236
1237         btrfs_release_path(root, path);
1238         *ref_ret = NULL;
1239
1240         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1241                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1242                                             root_objectid);
1243         } else {
1244                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1245                                              root_objectid, owner, offset);
1246         }
1247         return ret;
1248 }
1249
1250 static int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1251                                  struct btrfs_root *root,
1252                                  struct btrfs_path *path,
1253                                  struct btrfs_extent_inline_ref *iref,
1254                                  int refs_to_mod)
1255 {
1256         struct extent_buffer *leaf;
1257         struct btrfs_extent_item *ei;
1258         struct btrfs_extent_data_ref *dref = NULL;
1259         struct btrfs_shared_data_ref *sref = NULL;
1260         unsigned long ptr;
1261         unsigned long end;
1262         u32 item_size;
1263         int size;
1264         int type;
1265         int ret;
1266         u64 refs;
1267
1268         leaf = path->nodes[0];
1269         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1270         refs = btrfs_extent_refs(leaf, ei);
1271         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1272         refs += refs_to_mod;
1273         btrfs_set_extent_refs(leaf, ei, refs);
1274
1275         type = btrfs_extent_inline_ref_type(leaf, iref);
1276
1277         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1278                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1279                 refs = btrfs_extent_data_ref_count(leaf, dref);
1280         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1281                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1282                 refs = btrfs_shared_data_ref_count(leaf, sref);
1283         } else {
1284                 refs = 1;
1285                 BUG_ON(refs_to_mod != -1);
1286         }
1287
1288         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1289         refs += refs_to_mod;
1290
1291         if (refs > 0) {
1292                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1293                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1294                 else
1295                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1296         } else {
1297                 size =  btrfs_extent_inline_ref_size(type);
1298                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1299                 ptr = (unsigned long)iref;
1300                 end = (unsigned long)ei + item_size;
1301                 if (ptr + size < end)
1302                         memmove_extent_buffer(leaf, ptr, ptr + size,
1303                                               end - ptr - size);
1304                 item_size -= size;
1305                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1306                 BUG_ON(ret);
1307         }
1308         btrfs_mark_buffer_dirty(leaf);
1309         return 0;
1310 }
1311
1312 static int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1313                                  struct btrfs_root *root,
1314                                  struct btrfs_path *path,
1315                                  u64 bytenr, u64 num_bytes, u64 parent,
1316                                  u64 root_objectid, u64 owner,
1317                                  u64 offset, int refs_to_add)
1318 {
1319         struct btrfs_extent_inline_ref *iref;
1320         int ret;
1321
1322         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1323                                            bytenr, num_bytes, parent,
1324                                            root_objectid, owner, offset, 1);
1325         if (ret == 0) {
1326                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1327                 ret = update_inline_extent_backref(trans, root, path, iref,
1328                                                    refs_to_add);
1329         } else if (ret == -ENOENT) {
1330                 ret = setup_inline_extent_backref(trans, root, path, iref,
1331                                                   parent, root_objectid,
1332                                                   owner, offset, refs_to_add);
1333         }
1334         return ret;
1335 }
1336
1337 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1338                                  struct btrfs_root *root,
1339                                  struct btrfs_path *path,
1340                                  u64 bytenr, u64 parent, u64 root_objectid,
1341                                  u64 owner, u64 offset, int refs_to_add)
1342 {
1343         int ret;
1344
1345         if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
1346                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1347                                              parent, root_objectid,
1348                                              owner, offset, refs_to_add);
1349         } else {
1350                 BUG_ON(refs_to_add != 1);
1351                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1352                                             parent, root_objectid);
1353         }
1354         return ret;
1355 }
1356
1357 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1358                                  struct btrfs_root *root,
1359                                  struct btrfs_path *path,
1360                                  struct btrfs_extent_inline_ref *iref,
1361                                  int refs_to_drop, int is_data)
1362 {
1363         int ret;
1364
1365         BUG_ON(!is_data && refs_to_drop != 1);
1366         if (iref) {
1367                 ret = update_inline_extent_backref(trans, root, path, iref,
1368                                                    -refs_to_drop);
1369         } else if (is_data) {
1370                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1371         } else {
1372                 ret = btrfs_del_item(trans, root, path);
1373         }
1374         return ret;
1375 }
1376
1377 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1378                          struct btrfs_root *root,
1379                          u64 bytenr, u64 num_bytes, u64 parent,
1380                          u64 root_objectid, u64 owner, u64 offset)
1381 {
1382         struct btrfs_path *path;
1383         struct extent_buffer *leaf;
1384         struct btrfs_extent_item *item;
1385         u64 refs;
1386         int ret;
1387         int err = 0;
1388
1389         path = btrfs_alloc_path();
1390         if (!path)
1391                 return -ENOMEM;
1392
1393         path->reada = 1;
1394         path->leave_spinning = 1;
1395
1396         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1397                                            path, bytenr, num_bytes, parent,
1398                                            root_objectid, owner, offset, 1);
1399         if (ret == 0)
1400                 goto out;
1401
1402         if (ret != -EAGAIN) {
1403                 err = ret;
1404                 goto out;
1405         }
1406
1407         leaf = path->nodes[0];
1408         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1409         refs = btrfs_extent_refs(leaf, item);
1410         btrfs_set_extent_refs(leaf, item, refs + 1);
1411
1412         btrfs_mark_buffer_dirty(leaf);
1413         btrfs_release_path(root->fs_info->extent_root, path);
1414
1415         path->reada = 1;
1416         path->leave_spinning = 1;
1417
1418         /* now insert the actual backref */
1419         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1420                                     path, bytenr, parent, root_objectid,
1421                                     owner, offset, 1);
1422         if (ret)
1423                 err = ret;
1424 out:
1425         btrfs_free_path(path);
1426         finish_current_insert(trans, root->fs_info->extent_root);
1427         del_pending_extents(trans, root->fs_info->extent_root);
1428         BUG_ON(err);
1429         return err;
1430 }
1431
1432 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
1433                          struct btrfs_root *root)
1434 {
1435         finish_current_insert(trans, root->fs_info->extent_root);
1436         del_pending_extents(trans, root->fs_info->extent_root);
1437         return 0;
1438 }
1439
1440 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
1441                              struct btrfs_root *root, u64 bytenr,
1442                              u64 num_bytes, u64 *refs, u64 *flags)
1443 {
1444         struct btrfs_path *path;
1445         int ret;
1446         struct btrfs_key key;
1447         struct extent_buffer *l;
1448         struct btrfs_extent_item *item;
1449         u32 item_size;
1450         u64 num_refs;
1451         u64 extent_flags;
1452
1453         WARN_ON(num_bytes < root->sectorsize);
1454         path = btrfs_alloc_path();
1455         path->reada = 1;
1456         key.objectid = bytenr;
1457         key.offset = num_bytes;
1458         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1459         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1460                                 0, 0);
1461         if (ret < 0)
1462                 goto out;
1463         if (ret != 0) {
1464                 ret = -EIO;
1465                 goto out;
1466         }
1467
1468         l = path->nodes[0];
1469         item_size = btrfs_item_size_nr(l, path->slots[0]);
1470         if (item_size >= sizeof(*item)) {
1471                 item = btrfs_item_ptr(l, path->slots[0],
1472                                       struct btrfs_extent_item);
1473                 num_refs = btrfs_extent_refs(l, item);
1474                 extent_flags = btrfs_extent_flags(l, item);
1475         } else {
1476 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1477                         struct btrfs_extent_item_v0 *ei0;
1478                         BUG_ON(item_size != sizeof(*ei0));
1479                         ei0 = btrfs_item_ptr(l, path->slots[0],
1480                                              struct btrfs_extent_item_v0);
1481                         num_refs = btrfs_extent_refs_v0(l, ei0);
1482                         /* FIXME: this isn't correct for data */
1483                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
1484 #else
1485                         BUG();
1486 #endif
1487         }
1488         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1489         if (refs)
1490                 *refs = num_refs;
1491         if (flags)
1492                 *flags = extent_flags;
1493 out:
1494         btrfs_free_path(path);
1495         return 0;
1496 }
1497
1498 int btrfs_set_block_flags(struct btrfs_trans_handle *trans,
1499                           struct btrfs_root *root,
1500                           u64 bytenr, u64 num_bytes, u64 flags)
1501 {
1502         struct btrfs_path *path;
1503         int ret;
1504         struct btrfs_key key;
1505         struct extent_buffer *l;
1506         struct btrfs_extent_item *item;
1507         u32 item_size;
1508
1509         WARN_ON(num_bytes < root->sectorsize);
1510         path = btrfs_alloc_path();
1511         path->reada = 1;
1512         key.objectid = bytenr;
1513         key.offset = num_bytes;
1514         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1515         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1516                                 0, 0);
1517         if (ret < 0)
1518                 goto out;
1519         if (ret != 0) {
1520                 btrfs_print_leaf(root, path->nodes[0]);
1521                 printk("failed to find block number %Lu\n",
1522                         (unsigned long long)bytenr);
1523                 BUG();
1524         }
1525         l = path->nodes[0];
1526         item_size = btrfs_item_size_nr(l, path->slots[0]);
1527 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1528         if (item_size < sizeof(*item)) {
1529                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1530                                              path, (u64)-1, 0);
1531                 if (ret < 0)
1532                         goto out;
1533
1534                 l = path->nodes[0];
1535                 item_size = btrfs_item_size_nr(l, path->slots[0]);
1536         }
1537 #endif
1538         BUG_ON(item_size < sizeof(*item));
1539         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1540         flags |= btrfs_extent_flags(l, item);
1541         btrfs_set_extent_flags(l, item, flags);
1542 out:
1543         btrfs_free_path(path);
1544         finish_current_insert(trans, root->fs_info->extent_root);
1545         del_pending_extents(trans, root->fs_info->extent_root);
1546         return ret;
1547 }
1548
1549 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
1550                            struct btrfs_root *root,
1551                            struct extent_buffer *buf,
1552                            int record_parent, int inc)
1553 {
1554         u64 bytenr;
1555         u64 num_bytes;
1556         u64 parent;
1557         u64 ref_root;
1558         u32 nritems;
1559         struct btrfs_key key;
1560         struct btrfs_file_extent_item *fi;
1561         int i;
1562         int level;
1563         int ret = 0;
1564         int (*process_func)(struct btrfs_trans_handle *trans,
1565                             struct btrfs_root *root,
1566                             u64, u64, u64, u64, u64, u64);
1567
1568         ref_root = btrfs_header_owner(buf);
1569         nritems = btrfs_header_nritems(buf);
1570         level = btrfs_header_level(buf);
1571
1572         if (!root->ref_cows && level == 0)
1573                 return 0;
1574
1575         if (inc)
1576                 process_func = btrfs_inc_extent_ref;
1577         else
1578                 process_func = btrfs_free_extent;
1579
1580         if (record_parent)
1581                 parent = buf->start;
1582         else
1583                 parent = 0;
1584
1585         for (i = 0; i < nritems; i++) {
1586                 cond_resched();
1587                 if (level == 0) {
1588                         btrfs_item_key_to_cpu(buf, &key, i);
1589                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1590                                 continue;
1591                         fi = btrfs_item_ptr(buf, i,
1592                                             struct btrfs_file_extent_item);
1593                         if (btrfs_file_extent_type(buf, fi) ==
1594                             BTRFS_FILE_EXTENT_INLINE)
1595                                 continue;
1596                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1597                         if (bytenr == 0)
1598                                 continue;
1599
1600                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
1601                         key.offset -= btrfs_file_extent_offset(buf, fi);
1602                         ret = process_func(trans, root, bytenr, num_bytes,
1603                                            parent, ref_root, key.objectid,
1604                                            key.offset);
1605                         if (ret) {
1606                                 WARN_ON(1);
1607                                 goto fail;
1608                         }
1609                 } else {
1610                         bytenr = btrfs_node_blockptr(buf, i);
1611                         num_bytes = btrfs_level_size(root, level - 1);
1612                         ret = process_func(trans, root, bytenr, num_bytes,
1613                                            parent, ref_root, level - 1, 0);
1614                         if (ret) {
1615                                 WARN_ON(1);
1616                                 goto fail;
1617                         }
1618                 }
1619         }
1620         return 0;
1621 fail:
1622         WARN_ON(1);
1623         return ret;
1624 }
1625
1626 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1627                   struct extent_buffer *buf, int record_parent)
1628 {
1629         return __btrfs_mod_ref(trans, root, buf, record_parent, 1);
1630 }
1631
1632 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1633                   struct extent_buffer *buf, int record_parent)
1634 {
1635         return __btrfs_mod_ref(trans, root, buf, record_parent, 0);
1636 }
1637
1638 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1639                                  struct btrfs_root *root,
1640                                  struct btrfs_path *path,
1641                                  struct btrfs_block_group_cache *cache)
1642 {
1643         int ret;
1644         int pending_ret;
1645         struct btrfs_root *extent_root = root->fs_info->extent_root;
1646         unsigned long bi;
1647         struct extent_buffer *leaf;
1648
1649         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1650         if (ret < 0)
1651                 goto fail;
1652         BUG_ON(ret);
1653
1654         leaf = path->nodes[0];
1655         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1656         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1657         btrfs_mark_buffer_dirty(leaf);
1658         btrfs_release_path(extent_root, path);
1659 fail:
1660         finish_current_insert(trans, extent_root);
1661         pending_ret = del_pending_extents(trans, extent_root);
1662         if (ret)
1663                 return ret;
1664         if (pending_ret)
1665                 return pending_ret;
1666         return 0;
1667
1668 }
1669
1670 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1671                                    struct btrfs_root *root)
1672 {
1673         struct extent_io_tree *block_group_cache;
1674         struct btrfs_block_group_cache *cache;
1675         int ret;
1676         struct btrfs_path *path;
1677         u64 last = 0;
1678         u64 start;
1679         u64 end;
1680         u64 ptr;
1681
1682         block_group_cache = &root->fs_info->block_group_cache;
1683         path = btrfs_alloc_path();
1684         if (!path)
1685                 return -ENOMEM;
1686
1687         while(1) {
1688                 ret = find_first_extent_bit(block_group_cache, last,
1689                                             &start, &end, BLOCK_GROUP_DIRTY);
1690                 if (ret) {
1691                         if (last == 0)
1692                                 break;
1693                         last = 0;
1694                         continue;
1695                 }
1696
1697                 last = end + 1;
1698                 ret = get_state_private(block_group_cache, start, &ptr);
1699                 BUG_ON(ret);
1700
1701                 clear_extent_bits(block_group_cache, start, end,
1702                                   BLOCK_GROUP_DIRTY, GFP_NOFS);
1703
1704                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1705                 ret = write_one_cache_group(trans, root, path, cache);
1706         }
1707         btrfs_free_path(path);
1708         return 0;
1709 }
1710
1711 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1712                                                   u64 flags)
1713 {
1714         struct list_head *head = &info->space_info;
1715         struct list_head *cur;
1716         struct btrfs_space_info *found;
1717         list_for_each(cur, head) {
1718                 found = list_entry(cur, struct btrfs_space_info, list);
1719                 if (found->flags & flags)
1720                         return found;
1721         }
1722         return NULL;
1723
1724 }
1725
1726 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1727                              u64 total_bytes, u64 bytes_used,
1728                              struct btrfs_space_info **space_info)
1729 {
1730         struct btrfs_space_info *found;
1731
1732         found = __find_space_info(info, flags);
1733         if (found) {
1734                 found->total_bytes += total_bytes;
1735                 found->bytes_used += bytes_used;
1736                 if (found->total_bytes < found->bytes_used) {
1737                         fprintf(stderr, "warning, bad space info total_bytes "
1738                                 "%llu used %llu\n",
1739                                (unsigned long long)found->total_bytes,
1740                                (unsigned long long)found->bytes_used);
1741                 }
1742                 *space_info = found;
1743                 return 0;
1744         }
1745         found = kmalloc(sizeof(*found), GFP_NOFS);
1746         if (!found)
1747                 return -ENOMEM;
1748
1749         list_add(&found->list, &info->space_info);
1750         found->flags = flags;
1751         found->total_bytes = total_bytes;
1752         found->bytes_used = bytes_used;
1753         found->bytes_pinned = 0;
1754         found->full = 0;
1755         *space_info = found;
1756         return 0;
1757 }
1758
1759
1760 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1761 {
1762         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1763                                    BTRFS_BLOCK_GROUP_RAID1 |
1764                                    BTRFS_BLOCK_GROUP_RAID10 |
1765                                    BTRFS_BLOCK_GROUP_DUP);
1766         if (extra_flags) {
1767                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1768                         fs_info->avail_data_alloc_bits |= extra_flags;
1769                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1770                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1771                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1772                         fs_info->avail_system_alloc_bits |= extra_flags;
1773         }
1774 }
1775
1776 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1777                           struct btrfs_root *extent_root, u64 alloc_bytes,
1778                           u64 flags)
1779 {
1780         struct btrfs_space_info *space_info;
1781         u64 thresh;
1782         u64 start;
1783         u64 num_bytes;
1784         int ret;
1785
1786         space_info = __find_space_info(extent_root->fs_info, flags);
1787         if (!space_info) {
1788                 ret = update_space_info(extent_root->fs_info, flags,
1789                                         0, 0, &space_info);
1790                 BUG_ON(ret);
1791         }
1792         BUG_ON(!space_info);
1793
1794         if (space_info->full)
1795                 return 0;
1796
1797         thresh = div_factor(space_info->total_bytes, 7);
1798         if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1799             thresh)
1800                 return 0;
1801
1802         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes,
1803                                 space_info->flags);
1804         if (ret == -ENOSPC) {
1805                 space_info->full = 1;
1806                 return 0;
1807         }
1808
1809         BUG_ON(ret);
1810
1811         ret = btrfs_make_block_group(trans, extent_root, 0, space_info->flags,
1812                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1813         BUG_ON(ret);
1814         return 0;
1815 }
1816
1817 static int update_block_group(struct btrfs_trans_handle *trans,
1818                               struct btrfs_root *root,
1819                               u64 bytenr, u64 num_bytes, int alloc,
1820                               int mark_free)
1821 {
1822         struct btrfs_block_group_cache *cache;
1823         struct btrfs_fs_info *info = root->fs_info;
1824         u64 total = num_bytes;
1825         u64 old_val;
1826         u64 byte_in_group;
1827         u64 start;
1828         u64 end;
1829
1830         /* block accounting for super block */
1831         old_val = btrfs_super_bytes_used(&info->super_copy);
1832         if (alloc)
1833                 old_val += num_bytes;
1834         else
1835                 old_val -= num_bytes;
1836         btrfs_set_super_bytes_used(&info->super_copy, old_val);
1837
1838         /* block accounting for root item */
1839         old_val = btrfs_root_used(&root->root_item);
1840         if (alloc)
1841                 old_val += num_bytes;
1842         else
1843                 old_val -= num_bytes;
1844         btrfs_set_root_used(&root->root_item, old_val);
1845
1846         while(total) {
1847                 cache = btrfs_lookup_block_group(info, bytenr);
1848                 if (!cache) {
1849                         return -1;
1850                 }
1851                 byte_in_group = bytenr - cache->key.objectid;
1852                 WARN_ON(byte_in_group > cache->key.offset);
1853                 start = cache->key.objectid;
1854                 end = start + cache->key.offset - 1;
1855                 set_extent_bits(&info->block_group_cache, start, end,
1856                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1857
1858                 old_val = btrfs_block_group_used(&cache->item);
1859                 num_bytes = min(total, cache->key.offset - byte_in_group);
1860
1861                 if (alloc) {
1862                         old_val += num_bytes;
1863                         cache->space_info->bytes_used += num_bytes;
1864                 } else {
1865                         old_val -= num_bytes;
1866                         cache->space_info->bytes_used -= num_bytes;
1867                         if (mark_free) {
1868                                 set_extent_dirty(&info->free_space_cache,
1869                                                  bytenr, bytenr + num_bytes - 1,
1870                                                  GFP_NOFS);
1871                         }
1872                 }
1873                 btrfs_set_block_group_used(&cache->item, old_val);
1874                 total -= num_bytes;
1875                 bytenr += num_bytes;
1876         }
1877         return 0;
1878 }
1879
1880 static int update_pinned_extents(struct btrfs_root *root,
1881                                 u64 bytenr, u64 num, int pin)
1882 {
1883         u64 len;
1884         struct btrfs_block_group_cache *cache;
1885         struct btrfs_fs_info *fs_info = root->fs_info;
1886
1887         if (pin) {
1888                 set_extent_dirty(&fs_info->pinned_extents,
1889                                 bytenr, bytenr + num - 1, GFP_NOFS);
1890         } else {
1891                 clear_extent_dirty(&fs_info->pinned_extents,
1892                                 bytenr, bytenr + num - 1, GFP_NOFS);
1893         }
1894         while (num > 0) {
1895                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1896                 if (!cache) {
1897                         len = min((u64)root->sectorsize, num);
1898                         goto next;
1899                 }
1900                 WARN_ON(!cache);
1901                 len = min(num, cache->key.offset -
1902                           (bytenr - cache->key.objectid));
1903                 if (pin) {
1904                         cache->pinned += len;
1905                         cache->space_info->bytes_pinned += len;
1906                         fs_info->total_pinned += len;
1907                 } else {
1908                         cache->pinned -= len;
1909                         cache->space_info->bytes_pinned -= len;
1910                         fs_info->total_pinned -= len;
1911                 }
1912 next:
1913                 bytenr += len;
1914                 num -= len;
1915         }
1916         return 0;
1917 }
1918
1919 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1920 {
1921         u64 last = 0;
1922         u64 start;
1923         u64 end;
1924         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1925         int ret;
1926
1927         while(1) {
1928                 ret = find_first_extent_bit(pinned_extents, last,
1929                                             &start, &end, EXTENT_DIRTY);
1930                 if (ret)
1931                         break;
1932                 set_extent_dirty(copy, start, end, GFP_NOFS);
1933                 last = end + 1;
1934         }
1935         return 0;
1936 }
1937
1938 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1939                                struct btrfs_root *root,
1940                                struct extent_io_tree *unpin)
1941 {
1942         u64 start;
1943         u64 end;
1944         int ret;
1945         struct extent_io_tree *free_space_cache;
1946         free_space_cache = &root->fs_info->free_space_cache;
1947
1948         while(1) {
1949                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1950                                             EXTENT_DIRTY);
1951                 if (ret)
1952                         break;
1953                 update_pinned_extents(root, start, end + 1 - start, 0);
1954                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1955                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1956         }
1957         return 0;
1958 }
1959
1960 static int extent_root_pending_ops(struct btrfs_fs_info *info)
1961 {
1962         u64 start;
1963         u64 end;
1964         int ret;
1965
1966         ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1967                                     &end, EXTENT_LOCKED);
1968         if (!ret) {
1969                 ret = find_first_extent_bit(&info->pending_del, 0, &start, &end,
1970                                             EXTENT_LOCKED);
1971         }
1972         return ret == 0;
1973
1974 }
1975 static int finish_current_insert(struct btrfs_trans_handle *trans,
1976                                  struct btrfs_root *extent_root)
1977 {
1978         u64 start;
1979         u64 end;
1980         u64 priv;
1981         struct btrfs_fs_info *info = extent_root->fs_info;
1982         struct btrfs_path *path;
1983         struct pending_extent_op *extent_op;
1984         struct btrfs_key key;
1985         int ret;
1986
1987         path = btrfs_alloc_path();
1988
1989         while(1) {
1990                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1991                                             &end, EXTENT_LOCKED);
1992                 if (ret)
1993                         break;
1994
1995                 ret = get_state_private(&info->extent_ins, start, &priv);
1996                 BUG_ON(ret);
1997                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1998
1999                 if (extent_op->type == PENDING_EXTENT_INSERT) {
2000                         key.objectid = start;
2001                         key.offset = end + 1 - start;
2002                         key.type = BTRFS_EXTENT_ITEM_KEY;
2003                         ret = alloc_reserved_tree_block(trans, extent_root,
2004                                                 extent_root->root_key.objectid,
2005                                                 trans->transid,
2006                                                 extent_op->flags,
2007                                                 &extent_op->key,
2008                                                 extent_op->level, &key);
2009                 } else {
2010                         BUG_ON(1);
2011                 }
2012
2013                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
2014                                   GFP_NOFS);
2015                 kfree(extent_op);
2016         }
2017         btrfs_free_path(path);
2018         return 0;
2019 }
2020
2021 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2022                           struct btrfs_root *root,
2023                           u64 bytenr, u64 num_bytes, int is_data)
2024 {
2025         int err = 0;
2026         struct extent_buffer *buf;
2027
2028         if (is_data)
2029                 goto pinit;
2030
2031         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2032         if (!buf)
2033                 goto pinit;
2034
2035         /* we can reuse a block if it hasn't been written
2036          * and it is from this transaction.  We can't
2037          * reuse anything from the tree log root because
2038          * it has tiny sub-transactions.
2039          */
2040         if (btrfs_buffer_uptodate(buf, 0)) {
2041                 u64 header_owner = btrfs_header_owner(buf);
2042                 u64 header_transid = btrfs_header_generation(buf);
2043                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2044                     header_transid == trans->transid &&
2045                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2046                         clean_tree_block(NULL, root, buf);
2047                         free_extent_buffer(buf);
2048                         return 1;
2049                 }
2050         }
2051         free_extent_buffer(buf);
2052 pinit:
2053         update_pinned_extents(root, bytenr, num_bytes, 1);
2054
2055         BUG_ON(err < 0);
2056         return 0;
2057 }
2058
2059 void btrfs_pin_extent(struct btrfs_fs_info *fs_info,
2060                        u64 bytenr, u64 num_bytes)
2061 {
2062         update_pinned_extents(fs_info->extent_root, bytenr, num_bytes, 1);
2063 }
2064
2065 /*
2066  * remove an extent from the root, returns 0 on success
2067  */
2068 static int __free_extent(struct btrfs_trans_handle *trans,
2069                          struct btrfs_root *root,
2070                          u64 bytenr, u64 num_bytes, u64 parent,
2071                          u64 root_objectid, u64 owner_objectid,
2072                          u64 owner_offset, int refs_to_drop)
2073 {
2074
2075         struct btrfs_key key;
2076         struct btrfs_path *path;
2077         struct btrfs_extent_ops *ops = root->fs_info->extent_ops;
2078         struct btrfs_root *extent_root = root->fs_info->extent_root;
2079         struct extent_buffer *leaf;
2080         struct btrfs_extent_item *ei;
2081         struct btrfs_extent_inline_ref *iref;
2082         int ret;
2083         int is_data;
2084         int extent_slot = 0;
2085         int found_extent = 0;
2086         int num_to_del = 1;
2087         u32 item_size;
2088         u64 refs;
2089
2090         if (root->fs_info->free_extent_hook) {
2091                 root->fs_info->free_extent_hook(trans, root, bytenr, num_bytes,
2092                                                 parent, root_objectid, owner_objectid,
2093                                                 owner_offset, refs_to_drop);
2094
2095         }
2096         path = btrfs_alloc_path();
2097         if (!path)
2098                 return -ENOMEM;
2099
2100         path->reada = 1;
2101         path->leave_spinning = 1;
2102
2103         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2104         BUG_ON(!is_data && refs_to_drop != 1);
2105
2106         ret = lookup_extent_backref(trans, extent_root, path, &iref,
2107                                     bytenr, num_bytes, parent,
2108                                     root_objectid, owner_objectid,
2109                                     owner_offset);
2110         if (ret == 0) {
2111                 extent_slot = path->slots[0];
2112                 while (extent_slot >= 0) {
2113                         btrfs_item_key_to_cpu(path->nodes[0], &key,
2114                                               extent_slot);
2115                         if (key.objectid != bytenr)
2116                                 break;
2117                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2118                             key.offset == num_bytes) {
2119                                 found_extent = 1;
2120                                 break;
2121                         }
2122                         if (path->slots[0] - extent_slot > 5)
2123                                 break;
2124                         extent_slot--;
2125                 }
2126 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2127                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
2128                 if (found_extent && item_size < sizeof(*ei))
2129                         found_extent = 0;
2130 #endif
2131                 if (!found_extent) {
2132                         BUG_ON(iref);
2133                         ret = remove_extent_backref(trans, extent_root, path,
2134                                                     NULL, refs_to_drop,
2135                                                     is_data);
2136                         BUG_ON(ret);
2137                         btrfs_release_path(extent_root, path);
2138                         path->leave_spinning = 1;
2139
2140                         key.objectid = bytenr;
2141                         key.type = BTRFS_EXTENT_ITEM_KEY;
2142                         key.offset = num_bytes;
2143
2144                         ret = btrfs_search_slot(trans, extent_root,
2145                                                 &key, path, -1, 1);
2146                         if (ret) {
2147                                 printk(KERN_ERR "umm, got %d back from search"
2148                                        ", was looking for %llu\n", ret,
2149                                        (unsigned long long)bytenr);
2150                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2151                         }
2152                         BUG_ON(ret);
2153                         extent_slot = path->slots[0];
2154                 }
2155         } else {
2156                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2157                        "parent %llu root %llu  owner %llu offset %llu\n",
2158                        (unsigned long long)bytenr,
2159                        (unsigned long long)parent,
2160                        (unsigned long long)root_objectid,
2161                        (unsigned long long)owner_objectid,
2162                        (unsigned long long)owner_offset);
2163                 ret = -EIO;
2164                 goto fail;
2165         }
2166
2167         leaf = path->nodes[0];
2168         item_size = btrfs_item_size_nr(leaf, extent_slot);
2169 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2170         if (item_size < sizeof(*ei)) {
2171                 BUG_ON(found_extent || extent_slot != path->slots[0]);
2172                 ret = convert_extent_item_v0(trans, extent_root, path,
2173                                              owner_objectid, 0);
2174                 BUG_ON(ret < 0);
2175
2176                 btrfs_release_path(extent_root, path);
2177                 path->leave_spinning = 1;
2178
2179                 key.objectid = bytenr;
2180                 key.type = BTRFS_EXTENT_ITEM_KEY;
2181                 key.offset = num_bytes;
2182
2183                 ret = btrfs_search_slot(trans, extent_root, &key, path,
2184                                         -1, 1);
2185                 if (ret) {
2186                         printk(KERN_ERR "umm, got %d back from search"
2187                                ", was looking for %llu\n", ret,
2188                                (unsigned long long)bytenr);
2189                         btrfs_print_leaf(extent_root, path->nodes[0]);
2190                 }
2191                 BUG_ON(ret);
2192                 extent_slot = path->slots[0];
2193                 leaf = path->nodes[0];
2194                 item_size = btrfs_item_size_nr(leaf, extent_slot);
2195         }
2196 #endif
2197         BUG_ON(item_size < sizeof(*ei));
2198         ei = btrfs_item_ptr(leaf, extent_slot,
2199                             struct btrfs_extent_item);
2200         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2201                 struct btrfs_tree_block_info *bi;
2202                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
2203                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2204                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
2205         }
2206
2207         refs = btrfs_extent_refs(leaf, ei);
2208         BUG_ON(refs < refs_to_drop);
2209         refs -= refs_to_drop;
2210
2211         if (refs > 0) {
2212                 /*
2213                  * In the case of inline back ref, reference count will
2214                  * be updated by remove_extent_backref
2215                  */
2216                 if (iref) {
2217                         BUG_ON(!found_extent);
2218                 } else {
2219                         btrfs_set_extent_refs(leaf, ei, refs);
2220                         btrfs_mark_buffer_dirty(leaf);
2221                 }
2222                 if (found_extent) {
2223                         ret = remove_extent_backref(trans, extent_root, path,
2224                                                     iref, refs_to_drop,
2225                                                     is_data);
2226                         BUG_ON(ret);
2227                 }
2228         } else {
2229                 int mark_free = 0;
2230                 int pin = 1;
2231
2232                 if (found_extent) {
2233                         BUG_ON(is_data && refs_to_drop !=
2234                                extent_data_ref_count(root, path, iref));
2235                         if (iref) {
2236                                 BUG_ON(path->slots[0] != extent_slot);
2237                         } else {
2238                                 BUG_ON(path->slots[0] != extent_slot + 1);
2239                                 path->slots[0] = extent_slot;
2240                                 num_to_del = 2;
2241                         }
2242                 }
2243
2244                 if (ops && ops->free_extent) {
2245                         ret = ops->free_extent(root, bytenr, num_bytes);
2246                         if (ret > 0) {
2247                                 pin = 0;
2248                                 mark_free = 0;
2249                         }
2250                 }
2251
2252                 if (pin) {
2253                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
2254                                              is_data);
2255                         if (ret > 0)
2256                                 mark_free = 1;
2257                         BUG_ON(ret < 0);
2258                 }
2259
2260                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2261                                       num_to_del);
2262                 BUG_ON(ret);
2263                 btrfs_release_path(extent_root, path);
2264
2265                 if (is_data) {
2266                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2267                         BUG_ON(ret);
2268                 }
2269
2270                 update_block_group(trans, root, bytenr, num_bytes, 0, mark_free);
2271         }
2272 fail:
2273         btrfs_free_path(path);
2274         finish_current_insert(trans, extent_root);
2275         return ret;
2276 }
2277
2278 /*
2279  * find all the blocks marked as pending in the radix tree and remove
2280  * them from the extent map
2281  */
2282 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
2283                                btrfs_root *extent_root)
2284 {
2285         int ret;
2286         int err = 0;
2287         u64 start;
2288         u64 end;
2289         u64 priv;
2290         struct extent_io_tree *pending_del;
2291         struct extent_io_tree *extent_ins;
2292         struct pending_extent_op *extent_op;
2293
2294         extent_ins = &extent_root->fs_info->extent_ins;
2295         pending_del = &extent_root->fs_info->pending_del;
2296
2297         while(1) {
2298                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
2299                                             EXTENT_LOCKED);
2300                 if (ret)
2301                         break;
2302
2303                 ret = get_state_private(pending_del, start, &priv);
2304                 BUG_ON(ret);
2305                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2306
2307                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
2308                                   GFP_NOFS);
2309
2310                 if (!test_range_bit(extent_ins, start, end,
2311                                     EXTENT_LOCKED, 0)) {
2312                         ret = __free_extent(trans, extent_root,
2313                                             start, end + 1 - start, 0,
2314                                             extent_root->root_key.objectid,
2315                                             extent_op->level, 0, 1);
2316                         kfree(extent_op);
2317                 } else {
2318                         kfree(extent_op);
2319                         ret = get_state_private(extent_ins, start, &priv);
2320                         BUG_ON(ret);
2321                         extent_op = (struct pending_extent_op *)
2322                                                         (unsigned long)priv;
2323
2324                         clear_extent_bits(extent_ins, start, end,
2325                                           EXTENT_LOCKED, GFP_NOFS);
2326
2327                         if (extent_op->type == PENDING_BACKREF_UPDATE)
2328                                 BUG_ON(1);
2329
2330                         kfree(extent_op);
2331                 }
2332                 if (ret)
2333                         err = ret;
2334         }
2335         return err;
2336 }
2337
2338 /*
2339  * remove an extent from the root, returns 0 on success
2340  */
2341
2342 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2343                       struct btrfs_root *root,
2344                       u64 bytenr, u64 num_bytes, u64 parent,
2345                       u64 root_objectid, u64 owner, u64 offset)
2346 {
2347         struct btrfs_root *extent_root = root->fs_info->extent_root;
2348         int pending_ret;
2349         int ret;
2350
2351         WARN_ON(num_bytes < root->sectorsize);
2352         if (root == extent_root) {
2353                 struct pending_extent_op *extent_op;
2354
2355                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2356                 BUG_ON(!extent_op);
2357
2358                 extent_op->type = PENDING_EXTENT_DELETE;
2359                 extent_op->bytenr = bytenr;
2360                 extent_op->num_bytes = num_bytes;
2361                 extent_op->level = (int)owner;
2362
2363                 set_extent_bits(&root->fs_info->pending_del,
2364                                 bytenr, bytenr + num_bytes - 1,
2365                                 EXTENT_LOCKED, GFP_NOFS);
2366                 set_state_private(&root->fs_info->pending_del,
2367                                   bytenr, (unsigned long)extent_op);
2368                 return 0;
2369         }
2370         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2371                             root_objectid, owner, offset, 1);
2372         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
2373         return ret ? ret : pending_ret;
2374 }
2375
2376 static u64 stripe_align(struct btrfs_root *root, u64 val)
2377 {
2378         u64 mask = ((u64)root->stripesize - 1);
2379         u64 ret = (val + mask) & ~mask;
2380         return ret;
2381 }
2382
2383 /*
2384  * walks the btree of allocated extents and find a hole of a given size.
2385  * The key ins is changed to record the hole:
2386  * ins->objectid == block start
2387  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2388  * ins->offset == number of blocks
2389  * Any available blocks before search_start are skipped.
2390  */
2391 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
2392                                      struct btrfs_root *orig_root,
2393                                      u64 num_bytes, u64 empty_size,
2394                                      u64 search_start, u64 search_end,
2395                                      u64 hint_byte, struct btrfs_key *ins,
2396                                      u64 exclude_start, u64 exclude_nr,
2397                                      int data)
2398 {
2399         int ret;
2400         u64 orig_search_start = search_start;
2401         struct btrfs_root * root = orig_root->fs_info->extent_root;
2402         struct btrfs_fs_info *info = root->fs_info;
2403         u64 total_needed = num_bytes;
2404         struct btrfs_block_group_cache *block_group;
2405         int full_scan = 0;
2406         int wrapped = 0;
2407
2408         WARN_ON(num_bytes < root->sectorsize);
2409         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2410
2411         search_start = stripe_align(root, search_start);
2412
2413         if (hint_byte) {
2414                 block_group = btrfs_lookup_first_block_group(info, hint_byte);
2415                 if (!block_group)
2416                         hint_byte = search_start;
2417                 block_group = btrfs_find_block_group(root, block_group,
2418                                                      hint_byte, data, 1);
2419         } else {
2420                 block_group = btrfs_find_block_group(root,
2421                                                      trans->block_group,
2422                                                      search_start, data, 1);
2423         }
2424
2425         total_needed += empty_size;
2426
2427 check_failed:
2428         search_start = stripe_align(root, search_start);
2429         if (!block_group) {
2430                 block_group = btrfs_lookup_first_block_group(info,
2431                                                              search_start);
2432                 if (!block_group)
2433                         block_group = btrfs_lookup_first_block_group(info,
2434                                                        orig_search_start);
2435         }
2436         ret = find_search_start(root, &block_group, &search_start,
2437                                 total_needed, data);
2438         if (ret)
2439                 goto error;
2440
2441         ins->objectid = search_start;
2442         ins->offset = num_bytes;
2443
2444         if (ins->objectid + num_bytes >
2445             block_group->key.objectid + block_group->key.offset) {
2446                 search_start = block_group->key.objectid +
2447                         block_group->key.offset;
2448                 goto new_group;
2449         }
2450
2451         if (test_range_bit(&info->extent_ins, ins->objectid,
2452                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
2453                 search_start = ins->objectid + num_bytes;
2454                 goto new_group;
2455         }
2456
2457         if (test_range_bit(&info->pinned_extents, ins->objectid,
2458                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
2459                 search_start = ins->objectid + num_bytes;
2460                 goto new_group;
2461         }
2462
2463         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
2464             ins->objectid < exclude_start + exclude_nr)) {
2465                 search_start = exclude_start + exclude_nr;
2466                 goto new_group;
2467         }
2468
2469         if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
2470                 block_group = btrfs_lookup_block_group(info, ins->objectid);
2471                 if (block_group)
2472                         trans->block_group = block_group;
2473         }
2474         ins->offset = num_bytes;
2475         return 0;
2476
2477 new_group:
2478         block_group = btrfs_lookup_first_block_group(info, search_start);
2479         if (!block_group) {
2480                 search_start = orig_search_start;
2481                 if (full_scan) {
2482                         ret = -ENOSPC;
2483                         goto error;
2484                 }
2485                 if (wrapped) {
2486                         if (!full_scan)
2487                                 total_needed -= empty_size;
2488                         full_scan = 1;
2489                 } else
2490                         wrapped = 1;
2491         }
2492         cond_resched();
2493         block_group = btrfs_find_block_group(root, block_group,
2494                                              search_start, data, 0);
2495         goto check_failed;
2496
2497 error:
2498         return ret;
2499 }
2500
2501 static int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2502                                 struct btrfs_root *root,
2503                                 u64 num_bytes, u64 empty_size,
2504                                 u64 hint_byte, u64 search_end,
2505                                 struct btrfs_key *ins, int data)
2506 {
2507         int ret;
2508         u64 search_start = 0;
2509         u64 alloc_profile;
2510         struct btrfs_fs_info *info = root->fs_info;
2511
2512         if (info->extent_ops) {
2513                 struct btrfs_extent_ops *ops = info->extent_ops;
2514                 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
2515                 BUG_ON(ret);
2516                 goto found;
2517         }
2518
2519         if (data) {
2520                 alloc_profile = info->avail_data_alloc_bits &
2521                                 info->data_alloc_profile;
2522                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2523         } else if ((info->system_allocs > 0 || root == info->chunk_root) &&
2524                    info->system_allocs >= 0) {
2525                 alloc_profile = info->avail_system_alloc_bits &
2526                                 info->system_alloc_profile;
2527                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2528         } else {
2529                 alloc_profile = info->avail_metadata_alloc_bits &
2530                                 info->metadata_alloc_profile;
2531                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2532         }
2533
2534         if (root->ref_cows) {
2535                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2536                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2537                                              num_bytes,
2538                                              BTRFS_BLOCK_GROUP_METADATA);
2539                         BUG_ON(ret);
2540                 }
2541                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2542                                      num_bytes + 2 * 1024 * 1024, data);
2543                 BUG_ON(ret);
2544         }
2545
2546         WARN_ON(num_bytes < root->sectorsize);
2547         ret = find_free_extent(trans, root, num_bytes, empty_size,
2548                                search_start, search_end, hint_byte, ins,
2549                                trans->alloc_exclude_start,
2550                                trans->alloc_exclude_nr, data);
2551         BUG_ON(ret);
2552 found:
2553         clear_extent_dirty(&root->fs_info->free_space_cache,
2554                            ins->objectid, ins->objectid + ins->offset - 1,
2555                            GFP_NOFS);
2556         return ret;
2557 }
2558
2559 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
2560                                      struct btrfs_root *root,
2561                                      u64 root_objectid, u64 generation,
2562                                      u64 flags, struct btrfs_disk_key *key,
2563                                      int level, struct btrfs_key *ins)
2564 {
2565         int ret;
2566         struct btrfs_fs_info *fs_info = root->fs_info;
2567         struct btrfs_extent_item *extent_item;
2568         struct btrfs_tree_block_info *block_info;
2569         struct btrfs_extent_inline_ref *iref;
2570         struct btrfs_path *path;
2571         struct extent_buffer *leaf;
2572         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
2573
2574         path = btrfs_alloc_path();
2575         BUG_ON(!path);
2576
2577         path->leave_spinning = 1;
2578         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
2579                                       ins, size);
2580         BUG_ON(ret);
2581
2582         leaf = path->nodes[0];
2583         extent_item = btrfs_item_ptr(leaf, path->slots[0],
2584                                      struct btrfs_extent_item);
2585         btrfs_set_extent_refs(leaf, extent_item, 1);
2586         btrfs_set_extent_generation(leaf, extent_item, generation);
2587         btrfs_set_extent_flags(leaf, extent_item,
2588                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
2589         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
2590
2591         btrfs_set_tree_block_key(leaf, block_info, key);
2592         btrfs_set_tree_block_level(leaf, block_info, level);
2593
2594         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
2595         btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY);
2596         btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
2597
2598         btrfs_mark_buffer_dirty(leaf);
2599         btrfs_free_path(path);
2600
2601         ret = update_block_group(trans, root, ins->objectid, ins->offset,
2602                                  1, 0);
2603         return 0;
2604 }
2605
2606 static int alloc_tree_block(struct btrfs_trans_handle *trans,
2607                             struct btrfs_root *root, u64 num_bytes,
2608                             u64 root_objectid, u64 generation,
2609                             u64 flags, struct btrfs_disk_key *key,
2610                             int level, u64 empty_size, u64 hint_byte,
2611                             u64 search_end, struct btrfs_key *ins)
2612 {
2613         int ret;
2614         ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
2615                                    hint_byte, search_end, ins, 0);
2616         BUG_ON(ret);
2617
2618         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID) {
2619                 struct pending_extent_op *extent_op;
2620
2621                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2622                 BUG_ON(!extent_op);
2623
2624                 extent_op->type = PENDING_EXTENT_INSERT;
2625                 extent_op->bytenr = ins->objectid;
2626                 extent_op->num_bytes = ins->offset;
2627                 extent_op->level = level;
2628                 extent_op->flags = flags;
2629                 memcpy(&extent_op->key, key, sizeof(*key));
2630
2631                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2632                                 ins->objectid + ins->offset - 1,
2633                                 EXTENT_LOCKED, GFP_NOFS);
2634                 set_state_private(&root->fs_info->extent_ins,
2635                                   ins->objectid, (unsigned long)extent_op);
2636         } else {
2637                 ret = alloc_reserved_tree_block(trans, root, root_objectid,
2638                                                 generation, flags,
2639                                                 key, level, ins);
2640                 finish_current_insert(trans, root->fs_info->extent_root);
2641                 del_pending_extents(trans, root->fs_info->extent_root);
2642         }
2643         return ret;
2644 }
2645
2646 /*
2647  * helper function to allocate a block for a given tree
2648  * returns the tree buffer or NULL.
2649  */
2650 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2651                                         struct btrfs_root *root,
2652                                         u32 blocksize, u64 root_objectid,
2653                                         struct btrfs_disk_key *key, int level,
2654                                         u64 hint, u64 empty_size)
2655 {
2656         struct btrfs_key ins;
2657         int ret;
2658         struct extent_buffer *buf;
2659
2660         ret = alloc_tree_block(trans, root, blocksize, root_objectid,
2661                                trans->transid, 0, key, level,
2662                                empty_size, hint, (u64)-1, &ins);
2663         if (ret) {
2664                 BUG_ON(ret > 0);
2665                 return ERR_PTR(ret);
2666         }
2667
2668         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2669         if (!buf) {
2670                 btrfs_free_extent(trans, root, ins.objectid, ins.offset,
2671                                   0, root->root_key.objectid, level, 0);
2672                 BUG_ON(1);
2673                 return ERR_PTR(-ENOMEM);
2674         }
2675         btrfs_set_buffer_uptodate(buf);
2676         trans->blocks_used++;
2677
2678         return buf;
2679 }
2680
2681 #if 0
2682
2683 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2684                                   struct btrfs_root *root,
2685                                   struct extent_buffer *leaf)
2686 {
2687         u64 leaf_owner;
2688         u64 leaf_generation;
2689         struct btrfs_key key;
2690         struct btrfs_file_extent_item *fi;
2691         int i;
2692         int nritems;
2693         int ret;
2694
2695         BUG_ON(!btrfs_is_leaf(leaf));
2696         nritems = btrfs_header_nritems(leaf);
2697         leaf_owner = btrfs_header_owner(leaf);
2698         leaf_generation = btrfs_header_generation(leaf);
2699
2700         for (i = 0; i < nritems; i++) {
2701                 u64 disk_bytenr;
2702
2703                 btrfs_item_key_to_cpu(leaf, &key, i);
2704                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2705                         continue;
2706                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2707                 if (btrfs_file_extent_type(leaf, fi) ==
2708                     BTRFS_FILE_EXTENT_INLINE)
2709                         continue;
2710                 /*
2711                  * FIXME make sure to insert a trans record that
2712                  * repeats the snapshot del on crash
2713                  */
2714                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2715                 if (disk_bytenr == 0)
2716                         continue;
2717                 ret = btrfs_free_extent(trans, root, disk_bytenr,
2718                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2719                                 leaf->start, leaf_owner, leaf_generation,
2720                                 key.objectid, 0);
2721                 BUG_ON(ret);
2722         }
2723         return 0;
2724 }
2725
2726 static void noinline reada_walk_down(struct btrfs_root *root,
2727                                      struct extent_buffer *node,
2728                                      int slot)
2729 {
2730         u64 bytenr;
2731         u64 last = 0;
2732         u32 nritems;
2733         u32 refs;
2734         u32 blocksize;
2735         int ret;
2736         int i;
2737         int level;
2738         int skipped = 0;
2739
2740         nritems = btrfs_header_nritems(node);
2741         level = btrfs_header_level(node);
2742         if (level)
2743                 return;
2744
2745         for (i = slot; i < nritems && skipped < 32; i++) {
2746                 bytenr = btrfs_node_blockptr(node, i);
2747                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2748                              (last > bytenr && last - bytenr > 32 * 1024))) {
2749                         skipped++;
2750                         continue;
2751                 }
2752                 blocksize = btrfs_level_size(root, level - 1);
2753                 if (i != slot) {
2754                         ret = btrfs_lookup_extent_ref(NULL, root, bytenr,
2755                                                       blocksize, &refs);
2756                         BUG_ON(ret);
2757                         if (refs != 1) {
2758                                 skipped++;
2759                                 continue;
2760                         }
2761                 }
2762                 mutex_unlock(&root->fs_info->fs_mutex);
2763                 ret = readahead_tree_block(root, bytenr, blocksize,
2764                                            btrfs_node_ptr_generation(node, i));
2765                 last = bytenr + blocksize;
2766                 cond_resched();
2767                 mutex_lock(&root->fs_info->fs_mutex);
2768                 if (ret)
2769                         break;
2770         }
2771 }
2772
2773 /*
2774  * helper function for drop_snapshot, this walks down the tree dropping ref
2775  * counts as it goes.
2776  */
2777 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2778                                    struct btrfs_root *root,
2779                                    struct btrfs_path *path, int *level)
2780 {
2781         u64 root_owner;
2782         u64 root_gen;
2783         u64 bytenr;
2784         u64 ptr_gen;
2785         struct extent_buffer *next;
2786         struct extent_buffer *cur;
2787         struct extent_buffer *parent;
2788         u32 blocksize;
2789         int ret;
2790         u32 refs;
2791
2792         WARN_ON(*level < 0);
2793         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2794         ret = btrfs_lookup_extent_ref(trans, root,
2795                                       path->nodes[*level]->start,
2796                                       path->nodes[*level]->len, &refs);
2797         BUG_ON(ret);
2798         if (refs > 1)
2799                 goto out;
2800
2801         /*
2802          * walk down to the last node level and free all the leaves
2803          */
2804         while(*level >= 0) {
2805                 WARN_ON(*level < 0);
2806                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2807                 cur = path->nodes[*level];
2808
2809                 if (btrfs_header_level(cur) != *level)
2810                         WARN_ON(1);
2811
2812                 if (path->slots[*level] >=
2813                     btrfs_header_nritems(cur))
2814                         break;
2815                 if (*level == 0) {
2816                         ret = drop_leaf_ref(trans, root, cur);
2817                         BUG_ON(ret);
2818                         break;
2819                 }
2820                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2821                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2822                 blocksize = btrfs_level_size(root, *level - 1);
2823                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
2824                                               &refs);
2825                 BUG_ON(ret);
2826                 if (refs != 1) {
2827                         parent = path->nodes[*level];
2828                         root_owner = btrfs_header_owner(parent);
2829                         root_gen = btrfs_header_generation(parent);
2830                         path->slots[*level]++;
2831                         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
2832                                                 parent->start, root_owner,
2833                                                 root_gen, *level - 1, 1);
2834                         BUG_ON(ret);
2835                         continue;
2836                 }
2837                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2838                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2839                         free_extent_buffer(next);
2840                         reada_walk_down(root, cur, path->slots[*level]);
2841                         mutex_unlock(&root->fs_info->fs_mutex);
2842                         next = read_tree_block(root, bytenr, blocksize,
2843                                                ptr_gen);
2844                         mutex_lock(&root->fs_info->fs_mutex);
2845                 }
2846                 WARN_ON(*level <= 0);
2847                 if (path->nodes[*level-1])
2848                         free_extent_buffer(path->nodes[*level-1]);
2849                 path->nodes[*level-1] = next;
2850                 *level = btrfs_header_level(next);
2851                 path->slots[*level] = 0;
2852         }
2853 out:
2854         WARN_ON(*level < 0);
2855         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2856
2857         if (path->nodes[*level] == root->node) {
2858                 root_owner = root->root_key.objectid;
2859                 parent = path->nodes[*level];
2860         } else {
2861                 parent = path->nodes[*level + 1];
2862                 root_owner = btrfs_header_owner(parent);
2863         }
2864
2865         root_gen = btrfs_header_generation(parent);
2866         ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2867                                 path->nodes[*level]->len, parent->start,
2868                                 root_owner, root_gen, *level, 1);
2869         free_extent_buffer(path->nodes[*level]);
2870         path->nodes[*level] = NULL;
2871         *level += 1;
2872         BUG_ON(ret);
2873         return 0;
2874 }
2875
2876 /*
2877  * helper for dropping snapshots.  This walks back up the tree in the path
2878  * to find the first node higher up where we haven't yet gone through
2879  * all the slots
2880  */
2881 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2882                                  struct btrfs_root *root,
2883                                  struct btrfs_path *path, int *level)
2884 {
2885         u64 root_owner;
2886         u64 root_gen;
2887         struct btrfs_root_item *root_item = &root->root_item;
2888         int i;
2889         int slot;
2890         int ret;
2891
2892         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2893                 slot = path->slots[i];
2894                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2895                         struct extent_buffer *node;
2896                         struct btrfs_disk_key disk_key;
2897                         node = path->nodes[i];
2898                         path->slots[i]++;
2899                         *level = i;
2900                         WARN_ON(*level == 0);
2901                         btrfs_node_key(node, &disk_key, path->slots[i]);
2902                         memcpy(&root_item->drop_progress,
2903                                &disk_key, sizeof(disk_key));
2904                         root_item->drop_level = i;
2905                         return 0;
2906                 } else {
2907                         struct extent_buffer *parent;
2908                         if (path->nodes[*level] == root->node)
2909                                 parent = path->nodes[*level];
2910                         else
2911                                 parent = path->nodes[*level + 1];
2912
2913                         root_owner = btrfs_header_owner(parent);
2914                         root_gen = btrfs_header_generation(parent);
2915                         ret = btrfs_free_extent(trans, root,
2916                                                 path->nodes[*level]->start,
2917                                                 path->nodes[*level]->len,
2918                                                 parent->start, root_owner,
2919                                                 root_gen, *level, 1);
2920                         BUG_ON(ret);
2921                         free_extent_buffer(path->nodes[*level]);
2922                         path->nodes[*level] = NULL;
2923                         *level = i + 1;
2924                 }
2925         }
2926         return 1;
2927 }
2928
2929 /*
2930  * drop the reference count on the tree rooted at 'snap'.  This traverses
2931  * the tree freeing any blocks that have a ref count of zero after being
2932  * decremented.
2933  */
2934 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2935                         *root)
2936 {
2937         int ret = 0;
2938         int wret;
2939         int level;
2940         struct btrfs_path *path;
2941         int i;
2942         int orig_level;
2943         struct btrfs_root_item *root_item = &root->root_item;
2944
2945         path = btrfs_alloc_path();
2946         BUG_ON(!path);
2947
2948         level = btrfs_header_level(root->node);
2949         orig_level = level;
2950         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2951                 path->nodes[level] = root->node;
2952                 extent_buffer_get(root->node);
2953                 path->slots[level] = 0;
2954         } else {
2955                 struct btrfs_key key;
2956                 struct btrfs_disk_key found_key;
2957                 struct extent_buffer *node;
2958
2959                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2960                 level = root_item->drop_level;
2961                 path->lowest_level = level;
2962                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2963                 if (wret < 0) {
2964                         ret = wret;
2965                         goto out;
2966                 }
2967                 node = path->nodes[level];
2968                 btrfs_node_key(node, &found_key, path->slots[level]);
2969                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2970                                sizeof(found_key)));
2971         }
2972         while(1) {
2973                 wret = walk_down_tree(trans, root, path, &level);
2974                 if (wret < 0)
2975                         ret = wret;
2976                 if (wret != 0)
2977                         break;
2978
2979                 wret = walk_up_tree(trans, root, path, &level);
2980                 if (wret < 0)
2981                         ret = wret;
2982                 if (wret != 0)
2983                         break;
2984                 /*
2985                 ret = -EAGAIN;
2986                 break;
2987                 */
2988         }
2989         for (i = 0; i <= orig_level; i++) {
2990                 if (path->nodes[i]) {
2991                         free_extent_buffer(path->nodes[i]);
2992                         path->nodes[i] = NULL;
2993                 }
2994         }
2995 out:
2996         btrfs_free_path(path);
2997         return ret;
2998 }
2999
3000 #endif
3001
3002 int btrfs_free_block_groups(struct btrfs_fs_info *info)
3003 {
3004         u64 start;
3005         u64 end;
3006         u64 ptr;
3007         int ret;
3008         while(1) {
3009                 ret = find_first_extent_bit(&info->block_group_cache, 0,
3010                                             &start, &end, (unsigned int)-1);
3011                 if (ret)
3012                         break;
3013                 ret = get_state_private(&info->block_group_cache, start, &ptr);
3014                 if (!ret)
3015                         kfree((void *)(unsigned long)ptr);
3016                 clear_extent_bits(&info->block_group_cache, start,
3017                                   end, (unsigned int)-1, GFP_NOFS);
3018         }
3019         while(1) {
3020                 ret = find_first_extent_bit(&info->free_space_cache, 0,
3021                                             &start, &end, EXTENT_DIRTY);
3022                 if (ret)
3023                         break;
3024                 clear_extent_dirty(&info->free_space_cache, start,
3025                                    end, GFP_NOFS);
3026         }
3027         return 0;
3028 }
3029
3030 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3031                            struct btrfs_key *key)
3032 {
3033         int ret;
3034         struct btrfs_key found_key;
3035         struct extent_buffer *leaf;
3036         int slot;
3037
3038         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3039         if (ret < 0)
3040                 return ret;
3041         while(1) {
3042                 slot = path->slots[0];
3043                 leaf = path->nodes[0];
3044                 if (slot >= btrfs_header_nritems(leaf)) {
3045                         ret = btrfs_next_leaf(root, path);
3046                         if (ret == 0)
3047                                 continue;
3048                         if (ret < 0)
3049                                 goto error;
3050                         break;
3051                 }
3052                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3053
3054                 if (found_key.objectid >= key->objectid &&
3055                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
3056                         return 0;
3057                 path->slots[0]++;
3058         }
3059         ret = -ENOENT;
3060 error:
3061         return ret;
3062 }
3063
3064 int btrfs_read_block_groups(struct btrfs_root *root)
3065 {
3066         struct btrfs_path *path;
3067         int ret;
3068         int bit;
3069         struct btrfs_block_group_cache *cache;
3070         struct btrfs_fs_info *info = root->fs_info;
3071         struct btrfs_space_info *space_info;
3072         struct extent_io_tree *block_group_cache;
3073         struct btrfs_key key;
3074         struct btrfs_key found_key;
3075         struct extent_buffer *leaf;
3076
3077         block_group_cache = &info->block_group_cache;
3078
3079         root = info->extent_root;
3080         key.objectid = 0;
3081         key.offset = 0;
3082         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3083         path = btrfs_alloc_path();
3084         if (!path)
3085                 return -ENOMEM;
3086
3087         while(1) {
3088                 ret = find_first_block_group(root, path, &key);
3089                 if (ret > 0) {
3090                         ret = 0;
3091                         goto error;
3092                 }
3093                 if (ret != 0) {
3094                         goto error;
3095                 }
3096                 leaf = path->nodes[0];
3097                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3098                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3099                 if (!cache) {
3100                         ret = -ENOMEM;
3101                         break;
3102                 }
3103
3104                 read_extent_buffer(leaf, &cache->item,
3105                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
3106                                    sizeof(cache->item));
3107                 memcpy(&cache->key, &found_key, sizeof(found_key));
3108                 cache->cached = 0;
3109                 cache->pinned = 0;
3110                 key.objectid = found_key.objectid + found_key.offset;
3111                 btrfs_release_path(root, path);
3112                 cache->flags = btrfs_block_group_flags(&cache->item);
3113                 bit = 0;
3114                 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3115                         bit = BLOCK_GROUP_DATA;
3116                 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3117                         bit = BLOCK_GROUP_SYSTEM;
3118                 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3119                         bit = BLOCK_GROUP_METADATA;
3120                 }
3121                 set_avail_alloc_bits(info, cache->flags);
3122                 if (btrfs_chunk_readonly(root, cache->key.objectid))
3123                         cache->ro = 1;
3124
3125                 ret = update_space_info(info, cache->flags, found_key.offset,
3126                                         btrfs_block_group_used(&cache->item),
3127                                         &space_info);
3128                 BUG_ON(ret);
3129                 cache->space_info = space_info;
3130
3131                 /* use EXTENT_LOCKED to prevent merging */
3132                 set_extent_bits(block_group_cache, found_key.objectid,
3133                                 found_key.objectid + found_key.offset - 1,
3134                                 bit | EXTENT_LOCKED, GFP_NOFS);
3135                 set_state_private(block_group_cache, found_key.objectid,
3136                                   (unsigned long)cache);
3137         }
3138         ret = 0;
3139 error:
3140         btrfs_free_path(path);
3141         return ret;
3142 }
3143
3144 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3145                            struct btrfs_root *root, u64 bytes_used,
3146                            u64 type, u64 chunk_objectid, u64 chunk_offset,
3147                            u64 size)
3148 {
3149         int ret;
3150         int bit = 0;
3151         struct btrfs_root *extent_root;
3152         struct btrfs_block_group_cache *cache;
3153         struct extent_io_tree *block_group_cache;
3154
3155         extent_root = root->fs_info->extent_root;
3156         block_group_cache = &root->fs_info->block_group_cache;
3157
3158         cache = kzalloc(sizeof(*cache), GFP_NOFS);
3159         BUG_ON(!cache);
3160         cache->key.objectid = chunk_offset;
3161         cache->key.offset = size;
3162
3163         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3164         btrfs_set_block_group_used(&cache->item, bytes_used);
3165         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3166         cache->flags = type;
3167         btrfs_set_block_group_flags(&cache->item, type);
3168
3169         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3170                                 &cache->space_info);
3171         BUG_ON(ret);
3172
3173         bit = block_group_state_bits(type);
3174         set_extent_bits(block_group_cache, chunk_offset,
3175                         chunk_offset + size - 1,
3176                         bit | EXTENT_LOCKED, GFP_NOFS);
3177
3178         set_state_private(block_group_cache, chunk_offset,
3179                           (unsigned long)cache);
3180         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3181                                 sizeof(cache->item));
3182         BUG_ON(ret);
3183
3184         finish_current_insert(trans, extent_root);
3185         ret = del_pending_extents(trans, extent_root);
3186         set_avail_alloc_bits(extent_root->fs_info, type);
3187         return 0;
3188 }
3189
3190 /*
3191  * This is for converter use only.
3192  *
3193  * In that case, we don't know where are free blocks located.
3194  * Therefore all block group cache entries must be setup properly
3195  * before doing any block allocation.
3196  */
3197 int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
3198                             struct btrfs_root *root)
3199 {
3200         u64 total_bytes;
3201         u64 cur_start;
3202         u64 group_type;
3203         u64 group_size;
3204         u64 group_align;
3205         u64 total_data = 0;
3206         u64 total_metadata = 0;
3207         u64 chunk_objectid;
3208         int ret;
3209         int bit;
3210         struct btrfs_root *extent_root;
3211         struct btrfs_block_group_cache *cache;
3212         struct extent_io_tree *block_group_cache;
3213
3214         extent_root = root->fs_info->extent_root;
3215         block_group_cache = &root->fs_info->block_group_cache;
3216         chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3217         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
3218         group_align = 64 * root->sectorsize;
3219
3220         cur_start = 0;
3221         while (cur_start < total_bytes) {
3222                 group_size = total_bytes / 12;
3223                 group_size = min_t(u64, group_size, total_bytes - cur_start);
3224                 if (cur_start == 0) {
3225                         bit = BLOCK_GROUP_SYSTEM;
3226                         group_type = BTRFS_BLOCK_GROUP_SYSTEM;
3227                         group_size /= 4;
3228                         group_size &= ~(group_align - 1);
3229                         group_size = max_t(u64, group_size, 8 * 1024 * 1024);
3230                         group_size = min_t(u64, group_size, 32 * 1024 * 1024);
3231                 } else {
3232                         group_size &= ~(group_align - 1);
3233                         if (total_data >= total_metadata * 2) {
3234                                 group_type = BTRFS_BLOCK_GROUP_METADATA;
3235                                 group_size = min_t(u64, group_size,
3236                                                    1ULL * 1024 * 1024 * 1024);
3237                                 total_metadata += group_size;
3238                         } else {
3239                                 group_type = BTRFS_BLOCK_GROUP_DATA;
3240                                 group_size = min_t(u64, group_size,
3241                                                    5ULL * 1024 * 1024 * 1024);
3242                                 total_data += group_size;
3243                         }
3244                         if ((total_bytes - cur_start) * 4 < group_size * 5)
3245                                 group_size = total_bytes - cur_start;
3246                 }
3247
3248                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3249                 BUG_ON(!cache);
3250
3251                 cache->key.objectid = cur_start;
3252                 cache->key.offset = group_size;
3253                 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3254
3255                 btrfs_set_block_group_used(&cache->item, 0);
3256                 btrfs_set_block_group_chunk_objectid(&cache->item,
3257                                                      chunk_objectid);
3258                 btrfs_set_block_group_flags(&cache->item, group_type);
3259
3260                 cache->flags = group_type;
3261
3262                 ret = update_space_info(root->fs_info, group_type, group_size,
3263                                         0, &cache->space_info);
3264                 BUG_ON(ret);
3265                 set_avail_alloc_bits(extent_root->fs_info, group_type);
3266
3267                 set_extent_bits(block_group_cache, cur_start,
3268                                 cur_start + group_size - 1,
3269                                 bit | EXTENT_LOCKED, GFP_NOFS);
3270                 set_state_private(block_group_cache, cur_start,
3271                                   (unsigned long)cache);
3272                 cur_start += group_size;
3273         }
3274         /* then insert all the items */
3275         cur_start = 0;
3276         while(cur_start < total_bytes) {
3277                 cache = btrfs_lookup_block_group(root->fs_info, cur_start);
3278                 BUG_ON(!cache);
3279
3280                 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3281                                         sizeof(cache->item));
3282                 BUG_ON(ret);
3283
3284                 finish_current_insert(trans, extent_root);
3285                 ret = del_pending_extents(trans, extent_root);
3286                 BUG_ON(ret);
3287
3288                 cur_start = cache->key.objectid + cache->key.offset;
3289         }
3290         return 0;
3291 }
3292
3293 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3294                              struct btrfs_root *root,
3295                              u64 bytenr, u64 num_bytes, int alloc,
3296                              int mark_free)
3297 {
3298         return update_block_group(trans, root, bytenr, num_bytes,
3299                                   alloc, mark_free);
3300 }
3301
3302 static int btrfs_count_extents_in_block_group(struct btrfs_root *root,
3303                                               struct btrfs_path *path, u64 start,
3304                                               u64 len,
3305                                               u64 *total)
3306 {
3307         struct btrfs_key key;
3308         struct extent_buffer *leaf;
3309         u64 bytes_used = 0;
3310         int ret;
3311         int slot;
3312
3313         key.offset = 0;
3314         key.objectid = start;
3315         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
3316         ret = btrfs_search_slot(NULL, root->fs_info->extent_root,
3317                                 &key, path, 0, 0);
3318         if (ret < 0)
3319                 return ret;
3320         while(1) {
3321                 leaf = path->nodes[0];
3322                 slot = path->slots[0];
3323                 if (slot >= btrfs_header_nritems(leaf)) {
3324                         ret = btrfs_next_leaf(root, path);
3325                         if (ret < 0)
3326                                 return ret;
3327                         if (ret > 0)
3328                                 break;
3329                         leaf = path->nodes[0];
3330                         slot = path->slots[0];
3331                 }
3332                 btrfs_item_key_to_cpu(leaf, &key, slot);
3333                 if (key.objectid > start + len)
3334                         break;
3335                 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3336                         bytes_used += key.offset;
3337                 path->slots[0]++;
3338         }
3339         *total = bytes_used;
3340         btrfs_release_path(root, path);
3341         return 0;
3342 }
3343
3344 int btrfs_check_block_accounting(struct btrfs_root *root)
3345 {
3346         int ret;
3347         u64 start = 0;
3348         u64 bytes_used = 0;
3349         struct btrfs_path path;
3350         struct btrfs_block_group_cache *cache;
3351         struct btrfs_fs_info *fs_info = root->fs_info;
3352
3353         btrfs_init_path(&path);
3354
3355         while(1) {
3356                 cache = btrfs_lookup_block_group(fs_info, start);
3357                 if (!cache)
3358                         break;
3359
3360                 ret = btrfs_count_extents_in_block_group(root, &path,
3361                                                          cache->key.objectid,
3362                                                          cache->key.offset,
3363                                                          &bytes_used);
3364
3365                 if (ret == 0) {
3366                         u64 on_disk = btrfs_block_group_used(&cache->item);
3367                         if (on_disk != bytes_used) {
3368                                 fprintf(stderr, "bad block group accounting found %llu "
3369                                         "expected %llu block group %llu\n",
3370                                         (unsigned long long)bytes_used,
3371                                         (unsigned long long)on_disk,
3372                                         (unsigned long long)cache->key.objectid);
3373                         }
3374                 }
3375                 start = cache->key.objectid + cache->key.offset;
3376
3377                 cache->space_info->bytes_used = 0;
3378         }
3379         return 0;
3380 }
3381
3382 /*
3383  * Fixup block accounting. The initial block accounting created by
3384  * make_block_groups isn't accuracy in this case.
3385  */
3386 int btrfs_fix_block_accounting(struct btrfs_trans_handle *trans,
3387                                struct btrfs_root *root)
3388 {
3389         int ret;
3390         int slot;
3391         u64 start = 0;
3392         u64 bytes_used = 0;
3393         struct btrfs_path path;
3394         struct btrfs_key key;
3395         struct extent_buffer *leaf;
3396         struct btrfs_block_group_cache *cache;
3397         struct btrfs_fs_info *fs_info = root->fs_info;
3398
3399         root = root->fs_info->extent_root;
3400
3401         while(extent_root_pending_ops(fs_info)) {
3402                 ret = finish_current_insert(trans, root);
3403                 if (ret)
3404                         return ret;
3405                 ret = del_pending_extents(trans, root);
3406                 if (ret)
3407                         return ret;
3408         }
3409
3410         while(1) {
3411                 cache = btrfs_lookup_block_group(fs_info, start);
3412                 if (!cache)
3413                         break;
3414                 start = cache->key.objectid + cache->key.offset;
3415                 btrfs_set_block_group_used(&cache->item, 0);
3416                 cache->space_info->bytes_used = 0;
3417                 set_extent_bits(&root->fs_info->block_group_cache,
3418                                 cache->key.objectid,
3419                                 cache->key.objectid + cache->key.offset -1,
3420                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
3421         }
3422
3423         btrfs_init_path(&path);
3424         key.offset = 0;
3425         key.objectid = 0;
3426         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
3427         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
3428                                 &key, &path, 0, 0);
3429         if (ret < 0)
3430                 return ret;
3431         while(1) {
3432                 leaf = path.nodes[0];
3433                 slot = path.slots[0];
3434                 if (slot >= btrfs_header_nritems(leaf)) {
3435                         ret = btrfs_next_leaf(root, &path);
3436                         if (ret < 0)
3437                                 return ret;
3438                         if (ret > 0)
3439                                 break;
3440                         leaf = path.nodes[0];
3441                         slot = path.slots[0];
3442                 }
3443                 btrfs_item_key_to_cpu(leaf, &key, slot);
3444                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
3445                         bytes_used += key.offset;
3446                         ret = btrfs_update_block_group(trans, root,
3447                                   key.objectid, key.offset, 1, 0);
3448                         BUG_ON(ret);
3449                 }
3450                 path.slots[0]++;
3451         }
3452         btrfs_set_super_bytes_used(&root->fs_info->super_copy, bytes_used);
3453         btrfs_release_path(root, &path);
3454         return 0;
3455 }