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 <stdint.h>
  22 #include "kerncompat.h"
  23 #include "radix-tree.h"
  24 #include "ctree.h"
  25 #include "disk-io.h"
  26 #include "print-tree.h"
  27 #include "transaction.h"
  28 #include "crc32c.h"
  29 #include "volumes.h"
  30 #include "free-space-cache.h"
  31 #include "math.h"
  32
  33 #define PENDING_EXTENT_INSERT 0
  34 #define PENDING_EXTENT_DELETE 1
  35 #define PENDING_BACKREF_UPDATE 2
  36
  37 struct pending_extent_op {
  38         int type;
  39         u64 bytenr;
  40         u64 num_bytes;
  41         u64 flags;
  42         struct btrfs_disk_key key;
  43         int level;
  44 };
  45
  46 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  47                                      struct btrfs_root *root,
  48                                      u64 root_objectid, u64 generation,
  49                                      u64 flags, struct btrfs_disk_key *key,
  50                                      int level, struct btrfs_key *ins);
  51 static int __free_extent(struct btrfs_trans_handle *trans,
  52                          struct btrfs_root *root,
  53                          u64 bytenr, u64 num_bytes, u64 parent,
  54                          u64 root_objectid, u64 owner_objectid,
  55                          u64 owner_offset, int refs_to_drop);
  56 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  57                                  btrfs_root *extent_root);
  58 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  59                                btrfs_root *extent_root);
  60
  61 static int remove_sb_from_cache(struct btrfs_root *root,
  62                                 struct btrfs_block_group_cache *cache)
  63 {
  64         u64 bytenr;
  65         u64 *logical;
  66         int stripe_len;
  67         int i, nr, ret;
  68         struct extent_io_tree *free_space_cache;
  69
  70         free_space_cache = &root->fs_info->free_space_cache;
  71         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
  72                 bytenr = btrfs_sb_offset(i);
  73                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
  74                                        cache->key.objectid, bytenr, 0,
  75                                        &logical, &nr, &stripe_len);
  76                 BUG_ON(ret);
  77                 while (nr--) {
  78                         clear_extent_dirty(free_space_cache, logical[nr],
  79                                 logical[nr] + stripe_len - 1, GFP_NOFS);
  80                 }
  81                 kfree(logical);
  82         }
  83         return 0;
  84 }
  85
  86 static int cache_block_group(struct btrfs_root *root,
  87                              struct btrfs_block_group_cache *block_group)
  88 {
  89         struct btrfs_path *path;
  90         int ret;
  91         struct btrfs_key key;
  92         struct extent_buffer *leaf;
  93         struct extent_io_tree *free_space_cache;
  94         int slot;
  95         u64 last;
  96         u64 hole_size;
  97
  98         if (!block_group)
  99                 return 0;
 100
 101         root = root->fs_info->extent_root;
 102         free_space_cache = &root->fs_info->free_space_cache;
 103
 104         if (block_group->cached)
 105                 return 0;
 106
 107         path = btrfs_alloc_path();
 108         if (!path)
 109                 return -ENOMEM;
 110
 111         path->reada = 2;
 112         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 113         key.objectid = last;
 114         key.offset = 0;
 115         key.type = 0;
 116
 117         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 118         if (ret < 0)
 119                 goto err;
 120
 121         while(1) {
 122                 leaf = path->nodes[0];
 123                 slot = path->slots[0];
 124                 if (slot >= btrfs_header_nritems(leaf)) {
 125                         ret = btrfs_next_leaf(root, path);
 126                         if (ret < 0)
 127                                 goto err;
 128                         if (ret == 0) {
 129                                 continue;
 130                         } else {
 131                                 break;
 132                         }
 133                 }
 134                 btrfs_item_key_to_cpu(leaf, &key, slot);
 135                 if (key.objectid < block_group->key.objectid) {
 136                         goto next;
 137                 }
 138                 if (key.objectid >= block_group->key.objectid +
 139                     block_group->key.offset) {
 140                         break;
 141                 }
 142
 143                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 144                     key.type == BTRFS_METADATA_ITEM_KEY) {
 145                         if (key.objectid > last) {
 146                                 hole_size = key.objectid - last;
 147                                 set_extent_dirty(free_space_cache, last,
 148                                                  last + hole_size - 1,
 149                                                  GFP_NOFS);
 150                         }
 151                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 152                                 last = key.objectid + root->leafsize;
 153                         else
 154                                 last = key.objectid + key.offset;
 155                 }
 156 next:
 157                 path->slots[0]++;
 158         }
 159
 160         if (block_group->key.objectid +
 161             block_group->key.offset > last) {
 162                 hole_size = block_group->key.objectid +
 163                         block_group->key.offset - last;
 164                 set_extent_dirty(free_space_cache, last,
 165                                  last + hole_size - 1, GFP_NOFS);
 166         }
 167         remove_sb_from_cache(root, block_group);
 168         block_group->cached = 1;
 169 err:
 170         btrfs_free_path(path);
 171         return 0;
 172 }
 173
 174 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
 175                                                        btrfs_fs_info *info,
 176                                                        u64 bytenr)
 177 {
 178         struct extent_io_tree *block_group_cache;
 179         struct btrfs_block_group_cache *block_group = NULL;
 180         u64 ptr;
 181         u64 start;
 182         u64 end;
 183         int ret;
 184
 185         bytenr = max_t(u64, bytenr,
 186                        BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 187         block_group_cache = &info->block_group_cache;
 188         ret = find_first_extent_bit(block_group_cache,
 189                                     bytenr, &start, &end,
 190                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 191                                     BLOCK_GROUP_SYSTEM);
 192         if (ret) {
 193                 return NULL;
 194         }
 195         ret = get_state_private(block_group_cache, start, &ptr);
 196         if (ret)
 197                 return NULL;
 198
 199         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 200         return block_group;
 201 }
 202
 203 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 204                                                          btrfs_fs_info *info,
 205                                                          u64 bytenr)
 206 {
 207         struct extent_io_tree *block_group_cache;
 208         struct btrfs_block_group_cache *block_group = NULL;
 209         u64 ptr;
 210         u64 start;
 211         u64 end;
 212         int ret;
 213
 214         block_group_cache = &info->block_group_cache;
 215         ret = find_first_extent_bit(block_group_cache,
 216                                     bytenr, &start, &end,
 217                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 218                                     BLOCK_GROUP_SYSTEM);
 219         if (ret) {
 220                 return NULL;
 221         }
 222         ret = get_state_private(block_group_cache, start, &ptr);
 223         if (ret)
 224                 return NULL;
 225
 226         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 227         if (block_group->key.objectid <= bytenr && bytenr <
 228             block_group->key.objectid + block_group->key.offset)
 229                 return block_group;
 230         return NULL;
 231 }
 232
 233 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 234 {
 235         return (cache->flags & bits) == bits;
 236 }
 237
 238 static int noinline find_search_start(struct btrfs_root *root,
 239                               struct btrfs_block_group_cache **cache_ret,
 240                               u64 *start_ret, int num, int data)
 241 {
 242         int ret;
 243         struct btrfs_block_group_cache *cache = *cache_ret;
 244         u64 last = *start_ret;
 245         u64 start = 0;
 246         u64 end = 0;
 247         u64 search_start = *start_ret;
 248         int wrapped = 0;
 249
 250         if (!cache)
 251                 goto out;
 252 again:
 253         ret = cache_block_group(root, cache);
 254         if (ret)
 255                 goto out;
 256
 257         last = max(search_start, cache->key.objectid);
 258         if (cache->ro || !block_group_bits(cache, data))
 259                 goto new_group;
 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         *start_ret = last;
 281         cache = btrfs_lookup_block_group(root->fs_info, search_start);
 282         if (!cache) {
 283                 printk("Unable to find block group for %llu\n",
 284                         (unsigned long long)search_start);
 285                 WARN_ON(1);
 286         }
 287         return -ENOSPC;
 288
 289 new_group:
 290         last = cache->key.objectid + cache->key.offset;
 291 wrapped:
 292         cache = btrfs_lookup_first_block_group(root->fs_info, last);
 293         if (!cache) {
 294                 if (!wrapped) {
 295                         wrapped = 1;
 296                         last = search_start;
 297                         goto wrapped;
 298                 }
 299                 goto out;
 300         }
 301         *cache_ret = cache;
 302         goto again;
 303 }
 304
 305 static int block_group_state_bits(u64 flags)
 306 {
 307         int bits = 0;
 308         if (flags & BTRFS_BLOCK_GROUP_DATA)
 309                 bits |= BLOCK_GROUP_DATA;
 310         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 311                 bits |= BLOCK_GROUP_METADATA;
 312         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 313                 bits |= BLOCK_GROUP_SYSTEM;
 314         return bits;
 315 }
 316
 317 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 318                                                  struct btrfs_block_group_cache
 319                                                  *hint, u64 search_start,
 320                                                  int data, int owner)
 321 {
 322         struct btrfs_block_group_cache *cache;
 323         struct extent_io_tree *block_group_cache;
 324         struct btrfs_block_group_cache *found_group = NULL;
 325         struct btrfs_fs_info *info = root->fs_info;
 326         u64 used;
 327         u64 last = 0;
 328         u64 hint_last;
 329         u64 start;
 330         u64 end;
 331         u64 free_check;
 332         u64 ptr;
 333         int bit;
 334         int ret;
 335         int full_search = 0;
 336         int factor = 10;
 337
 338         block_group_cache = &info->block_group_cache;
 339
 340         if (!owner)
 341                 factor = 10;
 342
 343         bit = block_group_state_bits(data);
 344
 345         if (search_start) {
 346                 struct btrfs_block_group_cache *shint;
 347                 shint = btrfs_lookup_block_group(info, search_start);
 348                 if (shint && !shint->ro && block_group_bits(shint, data)) {
 349                         used = btrfs_block_group_used(&shint->item);
 350                         if (used + shint->pinned <
 351                             div_factor(shint->key.offset, factor)) {
 352                                 return shint;
 353                         }
 354                 }
 355         }
 356         if (hint && !hint->ro && block_group_bits(hint, data)) {
 357                 used = btrfs_block_group_used(&hint->item);
 358                 if (used + hint->pinned <
 359                     div_factor(hint->key.offset, factor)) {
 360                         return hint;
 361                 }
 362                 last = hint->key.objectid + hint->key.offset;
 363                 hint_last = last;
 364         } else {
 365                 if (hint)
 366                         hint_last = max(hint->key.objectid, search_start);
 367                 else
 368                         hint_last = search_start;
 369
 370                 last = hint_last;
 371         }
 372 again:
 373         while(1) {
 374                 ret = find_first_extent_bit(block_group_cache, last,
 375                                             &start, &end, bit);
 376                 if (ret)
 377                         break;
 378
 379                 ret = get_state_private(block_group_cache, start, &ptr);
 380                 if (ret)
 381                         break;
 382
 383                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 384                 last = cache->key.objectid + cache->key.offset;
 385                 used = btrfs_block_group_used(&cache->item);
 386
 387                 if (!cache->ro && block_group_bits(cache, data)) {
 388                         if (full_search)
 389                                 free_check = cache->key.offset;
 390                         else
 391                                 free_check = div_factor(cache->key.offset,
 392                                                         factor);
 393
 394                         if (used + cache->pinned < free_check) {
 395                                 found_group = cache;
 396                                 goto found;
 397                         }
 398                 }
 399                 cond_resched();
 400         }
 401         if (!full_search) {
 402                 last = search_start;
 403                 full_search = 1;
 404                 goto again;
 405         }
 406 found:
 407         return found_group;
 408 }
 409
 410 /*
 411  * Back reference rules.  Back refs have three main goals:
 412  *
 413  * 1) differentiate between all holders of references to an extent so that
 414  *    when a reference is dropped we can make sure it was a valid reference
 415  *    before freeing the extent.
 416  *
 417  * 2) Provide enough information to quickly find the holders of an extent
 418  *    if we notice a given block is corrupted or bad.
 419  *
 420  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 421  *    maintenance.  This is actually the same as #2, but with a slightly
 422  *    different use case.
 423  *
 424  * There are two kinds of back refs. The implicit back refs is optimized
 425  * for pointers in non-shared tree blocks. For a given pointer in a block,
 426  * back refs of this kind provide information about the block's owner tree
 427  * and the pointer's key. These information allow us to find the block by
 428  * b-tree searching. The full back refs is for pointers in tree blocks not
 429  * referenced by their owner trees. The location of tree block is recorded
 430  * in the back refs. Actually the full back refs is generic, and can be
 431  * used in all cases the implicit back refs is used. The major shortcoming
 432  * of the full back refs is its overhead. Every time a tree block gets
 433  * COWed, we have to update back refs entry for all pointers in it.
 434  *
 435  * For a newly allocated tree block, we use implicit back refs for
 436  * pointers in it. This means most tree related operations only involve
 437  * implicit back refs. For a tree block created in old transaction, the
 438  * only way to drop a reference to it is COW it. So we can detect the
 439  * event that tree block loses its owner tree's reference and do the
 440  * back refs conversion.
 441  *
 442  * When a tree block is COW'd through a tree, there are four cases:
 443  *
 444  * The reference count of the block is one and the tree is the block's
 445  * owner tree. Nothing to do in this case.
 446  *
 447  * The reference count of the block is one and the tree is not the
 448  * block's owner tree. In this case, full back refs is used for pointers
 449  * in the block. Remove these full back refs, add implicit back refs for
 450  * every pointers in the new block.
 451  *
 452  * The reference count of the block is greater than one and the tree is
 453  * the block's owner tree. In this case, implicit back refs is used for
 454  * pointers in the block. Add full back refs for every pointers in the
 455  * block, increase lower level extents' reference counts. The original
 456  * implicit back refs are entailed to the new block.
 457  *
 458  * The reference count of the block is greater than one and the tree is
 459  * not the block's owner tree. Add implicit back refs for every pointer in
 460  * the new block, increase lower level extents' reference count.
 461  *
 462  * Back Reference Key composing:
 463  *
 464  * The key objectid corresponds to the first byte in the extent,
 465  * The key type is used to differentiate between types of back refs.
 466  * There are different meanings of the key offset for different types
 467  * of back refs.
 468  *
 469  * File extents can be referenced by:
 470  *
 471  * - multiple snapshots, subvolumes, or different generations in one subvol
 472  * - different files inside a single subvolume
 473  * - different offsets inside a file (bookend extents in file.c)
 474  *
 475  * The extent ref structure for the implicit back refs has fields for:
 476  *
 477  * - Objectid of the subvolume root
 478  * - objectid of the file holding the reference
 479  * - original offset in the file
 480  * - how many bookend extents
 481  *
 482  * The key offset for the implicit back refs is hash of the first
 483  * three fields.
 484  *
 485  * The extent ref structure for the full back refs has field for:
 486  *
 487  * - number of pointers in the tree leaf
 488  *
 489  * The key offset for the implicit back refs is the first byte of
 490  * the tree leaf
 491  *
 492  * When a file extent is allocated, The implicit back refs is used.
 493  * the fields are filled in:
 494  *
 495  *     (root_key.objectid, inode objectid, offset in file, 1)
 496  *
 497  * When a file extent is removed file truncation, we find the
 498  * corresponding implicit back refs and check the following fields:
 499  *
 500  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 501  *
 502  * Btree extents can be referenced by:
 503  *
 504  * - Different subvolumes
 505  *
 506  * Both the implicit back refs and the full back refs for tree blocks
 507  * only consist of key. The key offset for the implicit back refs is
 508  * objectid of block's owner tree. The key offset for the full back refs
 509  * is the first byte of parent block.
 510  *
 511  * When implicit back refs is used, information about the lowest key and
 512  * level of the tree block are required. These information are stored in
 513  * tree block info structure.
 514  */
 515
 516 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 517 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 518                                   struct btrfs_root *root,
 519                                   struct btrfs_path *path,
 520                                   u64 owner, u32 extra_size)
 521 {
 522         struct btrfs_extent_item *item;
 523         struct btrfs_extent_item_v0 *ei0;
 524         struct btrfs_extent_ref_v0 *ref0;
 525         struct btrfs_tree_block_info *bi;
 526         struct extent_buffer *leaf;
 527         struct btrfs_key key;
 528         struct btrfs_key found_key;
 529         u32 new_size = sizeof(*item);
 530         u64 refs;
 531         int ret;
 532
 533         leaf = path->nodes[0];
 534         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 535
 536         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 537         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 538                              struct btrfs_extent_item_v0);
 539         refs = btrfs_extent_refs_v0(leaf, ei0);
 540
 541         if (owner == (u64)-1) {
 542                 while (1) {
 543                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 544                                 ret = btrfs_next_leaf(root, path);
 545                                 if (ret < 0)
 546                                         return ret;
 547                                 BUG_ON(ret > 0);
 548                                 leaf = path->nodes[0];
 549                         }
 550                         btrfs_item_key_to_cpu(leaf, &found_key,
 551                                               path->slots[0]);
 552                         BUG_ON(key.objectid != found_key.objectid);
 553                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 554                                 path->slots[0]++;
 555                                 continue;
 556                         }
 557                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 558                                               struct btrfs_extent_ref_v0);
 559                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 560                         break;
 561                 }
 562         }
 563         btrfs_release_path(root, path);
 564
 565         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 566                 new_size += sizeof(*bi);
 567
 568         new_size -= sizeof(*ei0);
 569         ret = btrfs_search_slot(trans, root, &key, path, new_size, 1);
 570         if (ret < 0)
 571                 return ret;
 572         BUG_ON(ret);
 573
 574         ret = btrfs_extend_item(trans, root, path, new_size);
 575         BUG_ON(ret);
 576
 577         leaf = path->nodes[0];
 578         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 579         btrfs_set_extent_refs(leaf, item, refs);
 580         /* FIXME: get real generation */
 581         btrfs_set_extent_generation(leaf, item, 0);
 582         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 583                 btrfs_set_extent_flags(leaf, item,
 584                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 585                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 586                 bi = (struct btrfs_tree_block_info *)(item + 1);
 587                 /* FIXME: get first key of the block */
 588                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 589                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 590         } else {
 591                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 592         }
 593         btrfs_mark_buffer_dirty(leaf);
 594         return 0;
 595 }
 596 #endif
 597
 598 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 599 {
 600         u32 high_crc = ~(u32)0;
 601         u32 low_crc = ~(u32)0;
 602         __le64 lenum;
 603
 604         lenum = cpu_to_le64(root_objectid);
 605         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 606         lenum = cpu_to_le64(owner);
 607         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 608         lenum = cpu_to_le64(offset);
 609         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 610
 611         return ((u64)high_crc << 31) ^ (u64)low_crc;
 612 }
 613
 614 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 615                                      struct btrfs_extent_data_ref *ref)
 616 {
 617         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 618                                     btrfs_extent_data_ref_objectid(leaf, ref),
 619                                     btrfs_extent_data_ref_offset(leaf, ref));
 620 }
 621
 622 static int match_extent_data_ref(struct extent_buffer *leaf,
 623                                  struct btrfs_extent_data_ref *ref,
 624                                  u64 root_objectid, u64 owner, u64 offset)
 625 {
 626         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 627             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 628             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 629                 return 0;
 630         return 1;
 631 }
 632
 633 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 634                                            struct btrfs_root *root,
 635                                            struct btrfs_path *path,
 636                                            u64 bytenr, u64 parent,
 637                                            u64 root_objectid,
 638                                            u64 owner, u64 offset)
 639 {
 640         struct btrfs_key key;
 641         struct btrfs_extent_data_ref *ref;
 642         struct extent_buffer *leaf;
 643         u32 nritems;
 644         int ret;
 645         int recow;
 646         int err = -ENOENT;
 647
 648         key.objectid = bytenr;
 649         if (parent) {
 650                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 651                 key.offset = parent;
 652         } else {
 653                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 654                 key.offset = hash_extent_data_ref(root_objectid,
 655                                                   owner, offset);
 656         }
 657 again:
 658         recow = 0;
 659         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 660         if (ret < 0) {
 661                 err = ret;
 662                 goto fail;
 663         }
 664
 665         if (parent) {
 666                 if (!ret)
 667                         return 0;
 668 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 669                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 670                 btrfs_release_path(root, path);
 671                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 672                 if (ret < 0) {
 673                         err = ret;
 674                         goto fail;
 675                 }
 676                 if (!ret)
 677                         return 0;
 678 #endif
 679                 goto fail;
 680         }
 681
 682         leaf = path->nodes[0];
 683         nritems = btrfs_header_nritems(leaf);
 684         while (1) {
 685                 if (path->slots[0] >= nritems) {
 686                         ret = btrfs_next_leaf(root, path);
 687                         if (ret < 0)
 688                                 err = ret;
 689                         if (ret)
 690                                 goto fail;
 691
 692                         leaf = path->nodes[0];
 693                         nritems = btrfs_header_nritems(leaf);
 694                         recow = 1;
 695                 }
 696
 697                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 698                 if (key.objectid != bytenr ||
 699                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 700                         goto fail;
 701
 702                 ref = btrfs_item_ptr(leaf, path->slots[0],
 703                                      struct btrfs_extent_data_ref);
 704
 705                 if (match_extent_data_ref(leaf, ref, root_objectid,
 706                                           owner, offset)) {
 707                         if (recow) {
 708                                 btrfs_release_path(root, path);
 709                                 goto again;
 710                         }
 711                         err = 0;
 712                         break;
 713                 }
 714                 path->slots[0]++;
 715         }
 716 fail:
 717         return err;
 718 }
 719
 720 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 721                                            struct btrfs_root *root,
 722                                            struct btrfs_path *path,
 723                                            u64 bytenr, u64 parent,
 724                                            u64 root_objectid, u64 owner,
 725                                            u64 offset, int refs_to_add)
 726 {
 727         struct btrfs_key key;
 728         struct extent_buffer *leaf;
 729         u32 size;
 730         u32 num_refs;
 731         int ret;
 732
 733         key.objectid = bytenr;
 734         if (parent) {
 735                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 736                 key.offset = parent;
 737                 size = sizeof(struct btrfs_shared_data_ref);
 738         } else {
 739                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 740                 key.offset = hash_extent_data_ref(root_objectid,
 741                                                   owner, offset);
 742                 size = sizeof(struct btrfs_extent_data_ref);
 743         }
 744
 745         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 746         if (ret && ret != -EEXIST)
 747                 goto fail;
 748
 749         leaf = path->nodes[0];
 750         if (parent) {
 751                 struct btrfs_shared_data_ref *ref;
 752                 ref = btrfs_item_ptr(leaf, path->slots[0],
 753                                      struct btrfs_shared_data_ref);
 754                 if (ret == 0) {
 755                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 756                 } else {
 757                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 758                         num_refs += refs_to_add;
 759                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 760                 }
 761         } else {
 762                 struct btrfs_extent_data_ref *ref;
 763                 while (ret == -EEXIST) {
 764                         ref = btrfs_item_ptr(leaf, path->slots[0],
 765                                              struct btrfs_extent_data_ref);
 766                         if (match_extent_data_ref(leaf, ref, root_objectid,
 767                                                   owner, offset))
 768                                 break;
 769                         btrfs_release_path(root, path);
 770
 771                         key.offset++;
 772                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 773                                                       size);
 774                         if (ret && ret != -EEXIST)
 775                                 goto fail;
 776
 777                         leaf = path->nodes[0];
 778                 }
 779                 ref = btrfs_item_ptr(leaf, path->slots[0],
 780                                      struct btrfs_extent_data_ref);
 781                 if (ret == 0) {
 782                         btrfs_set_extent_data_ref_root(leaf, ref,
 783                                                        root_objectid);
 784                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 785                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 786                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 787                 } else {
 788                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 789                         num_refs += refs_to_add;
 790                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 791                 }
 792         }
 793         btrfs_mark_buffer_dirty(leaf);
 794         ret = 0;
 795 fail:
 796         btrfs_release_path(root, path);
 797         return ret;
 798 }
 799
 800 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 801                                            struct btrfs_root *root,
 802                                            struct btrfs_path *path,
 803                                            int refs_to_drop)
 804 {
 805         struct btrfs_key key;
 806         struct btrfs_extent_data_ref *ref1 = NULL;
 807         struct btrfs_shared_data_ref *ref2 = NULL;
 808         struct extent_buffer *leaf;
 809         u32 num_refs = 0;
 810         int ret = 0;
 811
 812         leaf = path->nodes[0];
 813         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 814
 815         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 816                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 817                                       struct btrfs_extent_data_ref);
 818                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 819         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 820                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 821                                       struct btrfs_shared_data_ref);
 822                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 823 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 824         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 825                 struct btrfs_extent_ref_v0 *ref0;
 826                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 827                                       struct btrfs_extent_ref_v0);
 828                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 829 #endif
 830         } else {
 831                 BUG();
 832         }
 833
 834         BUG_ON(num_refs < refs_to_drop);
 835         num_refs -= refs_to_drop;
 836
 837         if (num_refs == 0) {
 838                 ret = btrfs_del_item(trans, root, path);
 839         } else {
 840                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 841                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 842                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 843                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 844 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 845                 else {
 846                         struct btrfs_extent_ref_v0 *ref0;
 847                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 848                                         struct btrfs_extent_ref_v0);
 849                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
 850                 }
 851 #endif
 852                 btrfs_mark_buffer_dirty(leaf);
 853         }
 854         return ret;
 855 }
 856
 857 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
 858                                           struct btrfs_path *path,
 859                                           struct btrfs_extent_inline_ref *iref)
 860 {
 861         struct btrfs_key key;
 862         struct extent_buffer *leaf;
 863         struct btrfs_extent_data_ref *ref1;
 864         struct btrfs_shared_data_ref *ref2;
 865         u32 num_refs = 0;
 866
 867         leaf = path->nodes[0];
 868         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 869         if (iref) {
 870                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
 871                     BTRFS_EXTENT_DATA_REF_KEY) {
 872                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 873                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 874                 } else {
 875                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 876                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 877                 }
 878         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 879                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 880                                       struct btrfs_extent_data_ref);
 881                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 882         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 883                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 884                                       struct btrfs_shared_data_ref);
 885                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 886 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 887         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 888                 struct btrfs_extent_ref_v0 *ref0;
 889                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 890                                       struct btrfs_extent_ref_v0);
 891                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 892 #endif
 893         } else {
 894                 BUG();
 895         }
 896         return num_refs;
 897 }
 898
 899 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 900                                           struct btrfs_root *root,
 901                                           struct btrfs_path *path,
 902                                           u64 bytenr, u64 parent,
 903                                           u64 root_objectid)
 904 {
 905         struct btrfs_key key;
 906         int ret;
 907
 908         key.objectid = bytenr;
 909         if (parent) {
 910                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 911                 key.offset = parent;
 912         } else {
 913                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 914                 key.offset = root_objectid;
 915         }
 916
 917         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 918         if (ret > 0)
 919                 ret = -ENOENT;
 920 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 921         if (ret == -ENOENT && parent) {
 922                 btrfs_release_path(root, path);
 923                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 924                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 925                 if (ret > 0)
 926                         ret = -ENOENT;
 927         }
 928 #endif
 929         return ret;
 930 }
 931
 932 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 933                                           struct btrfs_root *root,
 934                                           struct btrfs_path *path,
 935                                           u64 bytenr, u64 parent,
 936                                           u64 root_objectid)
 937 {
 938         struct btrfs_key key;
 939         int ret;
 940
 941         key.objectid = bytenr;
 942         if (parent) {
 943                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 944                 key.offset = parent;
 945         } else {
 946                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 947                 key.offset = root_objectid;
 948         }
 949
 950         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
 951
 952         btrfs_release_path(root, path);
 953         return ret;
 954 }
 955
 956 static inline int extent_ref_type(u64 parent, u64 owner)
 957 {
 958         int type;
 959         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 960                 if (parent > 0)
 961                         type = BTRFS_SHARED_BLOCK_REF_KEY;
 962                 else
 963                         type = BTRFS_TREE_BLOCK_REF_KEY;
 964         } else {
 965                 if (parent > 0)
 966                         type = BTRFS_SHARED_DATA_REF_KEY;
 967                 else
 968                         type = BTRFS_EXTENT_DATA_REF_KEY;
 969         }
 970         return type;
 971 }
 972
 973 static int find_next_key(struct btrfs_path *path, struct btrfs_key *key)
 974
 975 {
 976         int level;
 977         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
 978                 if (!path->nodes[level])
 979                         break;
 980                 if (path->slots[level] + 1 >=
 981                     btrfs_header_nritems(path->nodes[level]))
 982                         continue;
 983                 if (level == 0)
 984                         btrfs_item_key_to_cpu(path->nodes[level], key,
 985                                               path->slots[level] + 1);
 986                 else
 987                         btrfs_node_key_to_cpu(path->nodes[level], key,
 988                                               path->slots[level] + 1);
 989                 return 0;
 990         }
 991         return 1;
 992 }
 993
 994 static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 995                                  struct btrfs_root *root,
 996                                  struct btrfs_path *path,
 997                                  struct btrfs_extent_inline_ref **ref_ret,
 998                                  u64 bytenr, u64 num_bytes,
 999                                  u64 parent, u64 root_objectid,
1000                                  u64 owner, u64 offset, int insert)
1001 {
1002         struct btrfs_key key;
1003         struct extent_buffer *leaf;
1004         struct btrfs_extent_item *ei;
1005         struct btrfs_extent_inline_ref *iref;
1006         u64 flags;
1007         u32 item_size;
1008         unsigned long ptr;
1009         unsigned long end;
1010         int extra_size;
1011         int type;
1012         int want;
1013         int ret;
1014         int err = 0;
1015         int skinny_metadata =
1016                 btrfs_fs_incompat(root->fs_info,
1017                                   BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
1018
1019         key.objectid = bytenr;
1020         key.type = BTRFS_EXTENT_ITEM_KEY;
1021         key.offset = num_bytes;
1022
1023         want = extent_ref_type(parent, owner);
1024         if (insert)
1025                 extra_size = btrfs_extent_inline_ref_size(want);
1026         else
1027                 extra_size = -1;
1028
1029         if (owner < BTRFS_FIRST_FREE_OBJECTID && skinny_metadata) {
1030                 skinny_metadata = 1;
1031                 key.type = BTRFS_METADATA_ITEM_KEY;
1032                 key.offset = owner;
1033         } else if (skinny_metadata) {
1034                 skinny_metadata = 0;
1035         }
1036
1037 again:
1038         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1039         if (ret < 0) {
1040                 err = ret;
1041                 goto out;
1042         }
1043
1044         /*
1045          * We may be a newly converted file system which still has the old fat
1046          * extent entries for metadata, so try and see if we have one of those.
1047          */
1048         if (ret > 0 && skinny_metadata) {
1049                 skinny_metadata = 0;
1050                 if (path->slots[0]) {
1051                         path->slots[0]--;
1052                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1053                                               path->slots[0]);
1054                         if (key.objectid == bytenr &&
1055                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1056                             key.offset == num_bytes)
1057                                 ret = 0;
1058                 }
1059                 if (ret) {
1060                         key.type = BTRFS_EXTENT_ITEM_KEY;
1061                         key.offset = num_bytes;
1062                         goto again;
1063                 }
1064         }
1065
1066         if (ret) {
1067                 printf("Failed to find [%llu, %u, %llu]\n", key.objectid, key.type, key.offset);
1068                 return -ENOENT;
1069         }
1070
1071         BUG_ON(ret);
1072
1073         leaf = path->nodes[0];
1074         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1075 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1076         if (item_size < sizeof(*ei)) {
1077                 if (!insert) {
1078                         err = -ENOENT;
1079                         goto out;
1080                 }
1081                 ret = convert_extent_item_v0(trans, root, path, owner,
1082                                              extra_size);
1083                 if (ret < 0) {
1084                         err = ret;
1085                         goto out;
1086                 }
1087                 leaf = path->nodes[0];
1088                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1089         }
1090 #endif
1091         if (item_size < sizeof(*ei)) {
1092                 printf("Size is %u, needs to be %u, slot %d\n",
1093                        (unsigned)item_size,
1094                        (unsigned)sizeof(*ei), path->slots[0]);
1095                 btrfs_print_leaf(root, leaf);
1096                 return -EINVAL;
1097         }
1098         BUG_ON(item_size < sizeof(*ei));
1099
1100         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1101         flags = btrfs_extent_flags(leaf, ei);
1102
1103         ptr = (unsigned long)(ei + 1);
1104         end = (unsigned long)ei + item_size;
1105
1106         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1107                 ptr += sizeof(struct btrfs_tree_block_info);
1108                 BUG_ON(ptr > end);
1109         } else if (!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1110                 if (!(flags & BTRFS_EXTENT_FLAG_DATA)) {
1111                         return -EIO;
1112                 }
1113         }
1114
1115         err = -ENOENT;
1116         while (1) {
1117                 if (ptr >= end) {
1118                         WARN_ON(ptr > end);
1119                         break;
1120                 }
1121                 iref = (struct btrfs_extent_inline_ref *)ptr;
1122                 type = btrfs_extent_inline_ref_type(leaf, iref);
1123                 if (want < type)
1124                         break;
1125                 if (want > type) {
1126                         ptr += btrfs_extent_inline_ref_size(type);
1127                         continue;
1128                 }
1129
1130                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1131                         struct btrfs_extent_data_ref *dref;
1132                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1133                         if (match_extent_data_ref(leaf, dref, root_objectid,
1134                                                   owner, offset)) {
1135                                 err = 0;
1136                                 break;
1137                         }
1138                         if (hash_extent_data_ref_item(leaf, dref) <
1139                             hash_extent_data_ref(root_objectid, owner, offset))
1140                                 break;
1141                 } else {
1142                         u64 ref_offset;
1143                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1144                         if (parent > 0) {
1145                                 if (parent == ref_offset) {
1146                                         err = 0;
1147                                         break;
1148                                 }
1149                                 if (ref_offset < parent)
1150                                         break;
1151                         } else {
1152                                 if (root_objectid == ref_offset) {
1153                                         err = 0;
1154                                         break;
1155                                 }
1156                                 if (ref_offset < root_objectid)
1157                                         break;
1158                         }
1159                 }
1160                 ptr += btrfs_extent_inline_ref_size(type);
1161         }
1162         if (err == -ENOENT && insert) {
1163                 if (item_size + extra_size >=
1164                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1165                         err = -EAGAIN;
1166                         goto out;
1167                 }
1168                 /*
1169                  * To add new inline back ref, we have to make sure
1170                  * there is no corresponding back ref item.
1171                  * For simplicity, we just do not add new inline back
1172                  * ref if there is any back ref item.
1173                  */
1174                 if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&
1175                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1176                         err = -EAGAIN;
1177                         goto out;
1178                 }
1179         }
1180         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1181 out:
1182         return err;
1183 }
1184
1185 static int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1186                                 struct btrfs_root *root,
1187                                 struct btrfs_path *path,
1188                                 struct btrfs_extent_inline_ref *iref,
1189                                 u64 parent, u64 root_objectid,
1190                                 u64 owner, u64 offset, int refs_to_add)
1191 {
1192         struct extent_buffer *leaf;
1193         struct btrfs_extent_item *ei;
1194         unsigned long ptr;
1195         unsigned long end;
1196         unsigned long item_offset;
1197         u64 refs;
1198         int size;
1199         int type;
1200         int ret;
1201
1202         leaf = path->nodes[0];
1203         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1204         item_offset = (unsigned long)iref - (unsigned long)ei;
1205
1206         type = extent_ref_type(parent, owner);
1207         size = btrfs_extent_inline_ref_size(type);
1208
1209         ret = btrfs_extend_item(trans, root, path, size);
1210         BUG_ON(ret);
1211
1212         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1213         refs = btrfs_extent_refs(leaf, ei);
1214         refs += refs_to_add;
1215         btrfs_set_extent_refs(leaf, ei, refs);
1216
1217         ptr = (unsigned long)ei + item_offset;
1218         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1219         if (ptr < end - size)
1220                 memmove_extent_buffer(leaf, ptr + size, ptr,
1221                                       end - size - ptr);
1222
1223         iref = (struct btrfs_extent_inline_ref *)ptr;
1224         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1225         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1226                 struct btrfs_extent_data_ref *dref;
1227                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1228                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1229                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1230                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1231                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1232         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1233                 struct btrfs_shared_data_ref *sref;
1234                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1235                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1236                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1237         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1238                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1239         } else {
1240                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1241         }
1242         btrfs_mark_buffer_dirty(leaf);
1243         return 0;
1244 }
1245
1246 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1247                                  struct btrfs_root *root,
1248                                  struct btrfs_path *path,
1249                                  struct btrfs_extent_inline_ref **ref_ret,
1250                                  u64 bytenr, u64 num_bytes, u64 parent,
1251                                  u64 root_objectid, u64 owner, u64 offset)
1252 {
1253         int ret;
1254
1255         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1256                                            bytenr, num_bytes, parent,
1257                                            root_objectid, owner, offset, 0);
1258         if (ret != -ENOENT)
1259                 return ret;
1260
1261         btrfs_release_path(root, path);
1262         *ref_ret = NULL;
1263
1264         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1265                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1266                                             root_objectid);
1267         } else {
1268                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1269                                              root_objectid, owner, offset);
1270         }
1271         return ret;
1272 }
1273
1274 static int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1275                                  struct btrfs_root *root,
1276                                  struct btrfs_path *path,
1277                                  struct btrfs_extent_inline_ref *iref,
1278                                  int refs_to_mod)
1279 {
1280         struct extent_buffer *leaf;
1281         struct btrfs_extent_item *ei;
1282         struct btrfs_extent_data_ref *dref = NULL;
1283         struct btrfs_shared_data_ref *sref = NULL;
1284         unsigned long ptr;
1285         unsigned long end;
1286         u32 item_size;
1287         int size;
1288         int type;
1289         int ret;
1290         u64 refs;
1291
1292         leaf = path->nodes[0];
1293         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1294         refs = btrfs_extent_refs(leaf, ei);
1295         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1296         refs += refs_to_mod;
1297         btrfs_set_extent_refs(leaf, ei, refs);
1298
1299         type = btrfs_extent_inline_ref_type(leaf, iref);
1300
1301         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1302                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1303                 refs = btrfs_extent_data_ref_count(leaf, dref);
1304         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1305                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1306                 refs = btrfs_shared_data_ref_count(leaf, sref);
1307         } else {
1308                 refs = 1;
1309                 BUG_ON(refs_to_mod != -1);
1310         }
1311
1312         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1313         refs += refs_to_mod;
1314
1315         if (refs > 0) {
1316                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1317                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1318                 else
1319                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1320         } else {
1321                 size =  btrfs_extent_inline_ref_size(type);
1322                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1323                 ptr = (unsigned long)iref;
1324                 end = (unsigned long)ei + item_size;
1325                 if (ptr + size < end)
1326                         memmove_extent_buffer(leaf, ptr, ptr + size,
1327                                               end - ptr - size);
1328                 item_size -= size;
1329                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1330                 BUG_ON(ret);
1331         }
1332         btrfs_mark_buffer_dirty(leaf);
1333         return 0;
1334 }
1335
1336 static int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1337                                  struct btrfs_root *root,
1338                                  struct btrfs_path *path,
1339                                  u64 bytenr, u64 num_bytes, u64 parent,
1340                                  u64 root_objectid, u64 owner,
1341                                  u64 offset, int refs_to_add)
1342 {
1343         struct btrfs_extent_inline_ref *iref;
1344         int ret;
1345
1346         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1347                                            bytenr, num_bytes, parent,
1348                                            root_objectid, owner, offset, 1);
1349         if (ret == 0) {
1350                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1351                 ret = update_inline_extent_backref(trans, root, path, iref,
1352                                                    refs_to_add);
1353         } else if (ret == -ENOENT) {
1354                 ret = setup_inline_extent_backref(trans, root, path, iref,
1355                                                   parent, root_objectid,
1356                                                   owner, offset, refs_to_add);
1357         }
1358         return ret;
1359 }
1360
1361 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1362                                  struct btrfs_root *root,
1363                                  struct btrfs_path *path,
1364                                  u64 bytenr, u64 parent, u64 root_objectid,
1365                                  u64 owner, u64 offset, int refs_to_add)
1366 {
1367         int ret;
1368
1369         if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
1370                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1371                                              parent, root_objectid,
1372                                              owner, offset, refs_to_add);
1373         } else {
1374                 BUG_ON(refs_to_add != 1);
1375                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1376                                             parent, root_objectid);
1377         }
1378         return ret;
1379 }
1380
1381 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1382                                  struct btrfs_root *root,
1383                                  struct btrfs_path *path,
1384                                  struct btrfs_extent_inline_ref *iref,
1385                                  int refs_to_drop, int is_data)
1386 {
1387         int ret;
1388
1389         BUG_ON(!is_data && refs_to_drop != 1);
1390         if (iref) {
1391                 ret = update_inline_extent_backref(trans, root, path, iref,
1392                                                    -refs_to_drop);
1393         } else if (is_data) {
1394                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1395         } else {
1396                 ret = btrfs_del_item(trans, root, path);
1397         }
1398         return ret;
1399 }
1400
1401 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1402                          struct btrfs_root *root,
1403                          u64 bytenr, u64 num_bytes, u64 parent,
1404                          u64 root_objectid, u64 owner, u64 offset)
1405 {
1406         struct btrfs_path *path;
1407         struct extent_buffer *leaf;
1408         struct btrfs_extent_item *item;
1409         u64 refs;
1410         int ret;
1411         int err = 0;
1412
1413         path = btrfs_alloc_path();
1414         if (!path)
1415                 return -ENOMEM;
1416
1417         path->reada = 1;
1418         path->leave_spinning = 1;
1419
1420         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1421                                            path, bytenr, num_bytes, parent,
1422                                            root_objectid, owner, offset, 1);
1423         if (ret == 0)
1424                 goto out;
1425
1426         if (ret != -EAGAIN) {
1427                 err = ret;
1428                 goto out;
1429         }
1430
1431         leaf = path->nodes[0];
1432         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1433         refs = btrfs_extent_refs(leaf, item);
1434         btrfs_set_extent_refs(leaf, item, refs + 1);
1435
1436         btrfs_mark_buffer_dirty(leaf);
1437         btrfs_release_path(root->fs_info->extent_root, path);
1438
1439         path->reada = 1;
1440         path->leave_spinning = 1;
1441
1442         /* now insert the actual backref */
1443         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1444                                     path, bytenr, parent, root_objectid,
1445                                     owner, offset, 1);
1446         if (ret)
1447                 err = ret;
1448 out:
1449         btrfs_free_path(path);
1450         finish_current_insert(trans, root->fs_info->extent_root);
1451         del_pending_extents(trans, root->fs_info->extent_root);
1452         BUG_ON(err);
1453         return err;
1454 }
1455
1456 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
1457                          struct btrfs_root *root)
1458 {
1459         finish_current_insert(trans, root->fs_info->extent_root);
1460         del_pending_extents(trans, root->fs_info->extent_root);
1461         return 0;
1462 }
1463
1464 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
1465                              struct btrfs_root *root, u64 bytenr,
1466                              u64 offset, int metadata, u64 *refs, u64 *flags)
1467 {
1468         struct btrfs_path *path;
1469         int ret;
1470         struct btrfs_key key;
1471         struct extent_buffer *l;
1472         struct btrfs_extent_item *item;
1473         u32 item_size;
1474         u64 num_refs;
1475         u64 extent_flags;
1476
1477         if (metadata &&
1478             !btrfs_fs_incompat(root->fs_info,
1479                                BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)) {
1480                 offset = root->leafsize;
1481                 metadata = 0;
1482         }
1483
1484         path = btrfs_alloc_path();
1485         path->reada = 1;
1486
1487         key.objectid = bytenr;
1488         key.offset = offset;
1489         if (metadata)
1490                 key.type = BTRFS_METADATA_ITEM_KEY;
1491         else
1492                 key.type = BTRFS_EXTENT_ITEM_KEY;
1493
1494 again:
1495         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1496                                 0, 0);
1497         if (ret < 0)
1498                 goto out;
1499
1500         /*
1501          * Deal with the fact that we may have mixed SKINNY and normal refs.  If
1502          * we didn't find what we wanted check and see if we have a normal ref
1503          * right next to us, or re-search if we are on the edge of the leaf just
1504          * to make sure.
1505          */
1506         if (ret > 0 && metadata) {
1507                 if (path->slots) {
1508                         path->slots[0]--;
1509                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1510                                               path->slots[0]);
1511                         if (key.objectid == bytenr &&
1512                             key.type == BTRFS_METADATA_ITEM_KEY)
1513                                 ret = 0;
1514                 }
1515
1516                 if (ret) {
1517                         btrfs_release_path(root, path);
1518                         key.type = BTRFS_EXTENT_ITEM_KEY;
1519                         key.offset = root->leafsize;
1520                         metadata = 0;
1521                         goto again;
1522                 }
1523         }
1524
1525         if (ret != 0) {
1526                 ret = -EIO;
1527                 goto out;
1528         }
1529
1530         l = path->nodes[0];
1531         item_size = btrfs_item_size_nr(l, path->slots[0]);
1532         if (item_size >= sizeof(*item)) {
1533                 item = btrfs_item_ptr(l, path->slots[0],
1534                                       struct btrfs_extent_item);
1535                 num_refs = btrfs_extent_refs(l, item);
1536                 extent_flags = btrfs_extent_flags(l, item);
1537         } else {
1538 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1539                         struct btrfs_extent_item_v0 *ei0;
1540                         BUG_ON(item_size != sizeof(*ei0));
1541                         ei0 = btrfs_item_ptr(l, path->slots[0],
1542                                              struct btrfs_extent_item_v0);
1543                         num_refs = btrfs_extent_refs_v0(l, ei0);
1544                         /* FIXME: this isn't correct for data */
1545                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
1546 #else
1547                         BUG();
1548 #endif
1549         }
1550         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1551         if (refs)
1552                 *refs = num_refs;
1553         if (flags)
1554                 *flags = extent_flags;
1555 out:
1556         btrfs_free_path(path);
1557         return 0;
1558 }
1559
1560 int btrfs_set_block_flags(struct btrfs_trans_handle *trans,
1561                           struct btrfs_root *root,
1562                           u64 bytenr, int level, u64 flags)
1563 {
1564         struct btrfs_path *path;
1565         int ret;
1566         struct btrfs_key key;
1567         struct extent_buffer *l;
1568         struct btrfs_extent_item *item;
1569         u32 item_size;
1570         int skinny_metadata =
1571                 btrfs_fs_incompat(root->fs_info,
1572                                   BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
1573
1574         path = btrfs_alloc_path();
1575         path->reada = 1;
1576
1577         key.objectid = bytenr;
1578         if (skinny_metadata) {
1579                 key.offset = level;
1580                 key.type = BTRFS_METADATA_ITEM_KEY;
1581         } else {
1582                 key.offset = root->leafsize;
1583                 key.type = BTRFS_EXTENT_ITEM_KEY;
1584         }
1585
1586 again:
1587         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1588                                 0, 0);
1589         if (ret < 0)
1590                 goto out;
1591
1592         if (ret > 0 && skinny_metadata) {
1593                 skinny_metadata = 0;
1594                 if (path->slots[0]--) {
1595                         path->slots[0]--;
1596                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1597                                               path->slots[0]);
1598                         if (key.objectid == bytenr &&
1599                             key.offset == root->leafsize &&
1600                             key.type == BTRFS_EXTENT_ITEM_KEY)
1601                                 ret = 0;
1602                 }
1603                 if (ret) {
1604                         btrfs_release_path(root, path);
1605                         key.offset = root->leafsize;
1606                         key.type = BTRFS_EXTENT_ITEM_KEY;
1607                         goto again;
1608                 }
1609         }
1610
1611         if (ret != 0) {
1612                 btrfs_print_leaf(root, path->nodes[0]);
1613                 printk("failed to find block number %Lu\n",
1614                         (unsigned long long)bytenr);
1615                 BUG();
1616         }
1617         l = path->nodes[0];
1618         item_size = btrfs_item_size_nr(l, path->slots[0]);
1619 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1620         if (item_size < sizeof(*item)) {
1621                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1622                                              path, (u64)-1, 0);
1623                 if (ret < 0)
1624                         goto out;
1625
1626                 l = path->nodes[0];
1627                 item_size = btrfs_item_size_nr(l, path->slots[0]);
1628         }
1629 #endif
1630         BUG_ON(item_size < sizeof(*item));
1631         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1632         flags |= btrfs_extent_flags(l, item);
1633         btrfs_set_extent_flags(l, item, flags);
1634 out:
1635         btrfs_free_path(path);
1636         finish_current_insert(trans, root->fs_info->extent_root);
1637         del_pending_extents(trans, root->fs_info->extent_root);
1638         return ret;
1639 }
1640
1641 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
1642                            struct btrfs_root *root,
1643                            struct extent_buffer *buf,
1644                            int record_parent, int inc)
1645 {
1646         u64 bytenr;
1647         u64 num_bytes;
1648         u64 parent;
1649         u64 ref_root;
1650         u32 nritems;
1651         struct btrfs_key key;
1652         struct btrfs_file_extent_item *fi;
1653         int i;
1654         int level;
1655         int ret = 0;
1656         int (*process_func)(struct btrfs_trans_handle *trans,
1657                             struct btrfs_root *root,
1658                             u64, u64, u64, u64, u64, u64);
1659
1660         ref_root = btrfs_header_owner(buf);
1661         nritems = btrfs_header_nritems(buf);
1662         level = btrfs_header_level(buf);
1663
1664         if (!root->ref_cows && level == 0)
1665                 return 0;
1666
1667         if (inc)
1668                 process_func = btrfs_inc_extent_ref;
1669         else
1670                 process_func = btrfs_free_extent;
1671
1672         if (record_parent)
1673                 parent = buf->start;
1674         else
1675                 parent = 0;
1676
1677         for (i = 0; i < nritems; i++) {
1678                 cond_resched();
1679                 if (level == 0) {
1680                         btrfs_item_key_to_cpu(buf, &key, i);
1681                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1682                                 continue;
1683                         fi = btrfs_item_ptr(buf, i,
1684                                             struct btrfs_file_extent_item);
1685                         if (btrfs_file_extent_type(buf, fi) ==
1686                             BTRFS_FILE_EXTENT_INLINE)
1687                                 continue;
1688                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1689                         if (bytenr == 0)
1690                                 continue;
1691
1692                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
1693                         key.offset -= btrfs_file_extent_offset(buf, fi);
1694                         ret = process_func(trans, root, bytenr, num_bytes,
1695                                            parent, ref_root, key.objectid,
1696                                            key.offset);
1697                         if (ret) {
1698                                 WARN_ON(1);
1699                                 goto fail;
1700                         }
1701                 } else {
1702                         bytenr = btrfs_node_blockptr(buf, i);
1703                         num_bytes = btrfs_level_size(root, level - 1);
1704                         ret = process_func(trans, root, bytenr, num_bytes,
1705                                            parent, ref_root, level - 1, 0);
1706                         if (ret) {
1707                                 WARN_ON(1);
1708                                 goto fail;
1709                         }
1710                 }
1711         }
1712         return 0;
1713 fail:
1714         WARN_ON(1);
1715         return ret;
1716 }
1717
1718 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1719                   struct extent_buffer *buf, int record_parent)
1720 {
1721         return __btrfs_mod_ref(trans, root, buf, record_parent, 1);
1722 }
1723
1724 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1725                   struct extent_buffer *buf, int record_parent)
1726 {
1727         return __btrfs_mod_ref(trans, root, buf, record_parent, 0);
1728 }
1729
1730 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1731                                  struct btrfs_root *root,
1732                                  struct btrfs_path *path,
1733                                  struct btrfs_block_group_cache *cache)
1734 {
1735         int ret;
1736         int pending_ret;
1737         struct btrfs_root *extent_root = root->fs_info->extent_root;
1738         unsigned long bi;
1739         struct extent_buffer *leaf;
1740
1741         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1742         if (ret < 0)
1743                 goto fail;
1744         BUG_ON(ret);
1745
1746         leaf = path->nodes[0];
1747         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1748         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1749         btrfs_mark_buffer_dirty(leaf);
1750         btrfs_release_path(extent_root, path);
1751 fail:
1752         finish_current_insert(trans, extent_root);
1753         pending_ret = del_pending_extents(trans, extent_root);
1754         if (ret)
1755                 return ret;
1756         if (pending_ret)
1757                 return pending_ret;
1758         return 0;
1759
1760 }
1761
1762 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1763                                    struct btrfs_root *root)
1764 {
1765         struct extent_io_tree *block_group_cache;
1766         struct btrfs_block_group_cache *cache;
1767         int ret;
1768         struct btrfs_path *path;
1769         u64 last = 0;
1770         u64 start;
1771         u64 end;
1772         u64 ptr;
1773
1774         block_group_cache = &root->fs_info->block_group_cache;
1775         path = btrfs_alloc_path();
1776         if (!path)
1777                 return -ENOMEM;
1778
1779         while(1) {
1780                 ret = find_first_extent_bit(block_group_cache, last,
1781                                             &start, &end, BLOCK_GROUP_DIRTY);
1782                 if (ret) {
1783                         if (last == 0)
1784                                 break;
1785                         last = 0;
1786                         continue;
1787                 }
1788
1789                 last = end + 1;
1790                 ret = get_state_private(block_group_cache, start, &ptr);
1791                 BUG_ON(ret);
1792
1793                 clear_extent_bits(block_group_cache, start, end,
1794                                   BLOCK_GROUP_DIRTY, GFP_NOFS);
1795
1796                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1797                 ret = write_one_cache_group(trans, root, path, cache);
1798         }
1799         btrfs_free_path(path);
1800         return 0;
1801 }
1802
1803 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1804                                                   u64 flags)
1805 {
1806         struct list_head *head = &info->space_info;
1807         struct list_head *cur;
1808         struct btrfs_space_info *found;
1809         list_for_each(cur, head) {
1810                 found = list_entry(cur, struct btrfs_space_info, list);
1811                 if (found->flags & flags)
1812                         return found;
1813         }
1814         return NULL;
1815
1816 }
1817
1818 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1819                              u64 total_bytes, u64 bytes_used,
1820                              struct btrfs_space_info **space_info)
1821 {
1822         struct btrfs_space_info *found;
1823
1824         found = __find_space_info(info, flags);
1825         if (found) {
1826                 found->total_bytes += total_bytes;
1827                 found->bytes_used += bytes_used;
1828                 if (found->total_bytes < found->bytes_used) {
1829                         fprintf(stderr, "warning, bad space info total_bytes "
1830                                 "%llu used %llu\n",
1831                                (unsigned long long)found->total_bytes,
1832                                (unsigned long long)found->bytes_used);
1833                 }
1834                 *space_info = found;
1835                 return 0;
1836         }
1837         found = kmalloc(sizeof(*found), GFP_NOFS);
1838         if (!found)
1839                 return -ENOMEM;
1840
1841         list_add(&found->list, &info->space_info);
1842         found->flags = flags;
1843         found->total_bytes = total_bytes;
1844         found->bytes_used = bytes_used;
1845         found->bytes_pinned = 0;
1846         found->full = 0;
1847         *space_info = found;
1848         return 0;
1849 }
1850
1851
1852 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1853 {
1854         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1855                                    BTRFS_BLOCK_GROUP_RAID1 |
1856                                    BTRFS_BLOCK_GROUP_RAID10 |
1857                                    BTRFS_BLOCK_GROUP_RAID5 |
1858                                    BTRFS_BLOCK_GROUP_RAID6 |
1859                                    BTRFS_BLOCK_GROUP_DUP);
1860         if (extra_flags) {
1861                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1862                         fs_info->avail_data_alloc_bits |= extra_flags;
1863                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1864                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1865                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1866                         fs_info->avail_system_alloc_bits |= extra_flags;
1867         }
1868 }
1869
1870 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1871                           struct btrfs_root *extent_root, u64 alloc_bytes,
1872                           u64 flags)
1873 {
1874         struct btrfs_space_info *space_info;
1875         u64 thresh;
1876         u64 start;
1877         u64 num_bytes;
1878         int ret;
1879
1880         space_info = __find_space_info(extent_root->fs_info, flags);
1881         if (!space_info) {
1882                 ret = update_space_info(extent_root->fs_info, flags,
1883                                         0, 0, &space_info);
1884                 BUG_ON(ret);
1885         }
1886         BUG_ON(!space_info);
1887
1888         if (space_info->full)
1889                 return 0;
1890
1891         thresh = div_factor(space_info->total_bytes, 7);
1892         if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1893             thresh)
1894                 return 0;
1895
1896         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes,
1897                                 space_info->flags);
1898         if (ret == -ENOSPC) {
1899                 space_info->full = 1;
1900                 return 0;
1901         }
1902
1903         BUG_ON(ret);
1904
1905         ret = btrfs_make_block_group(trans, extent_root, 0, space_info->flags,
1906                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1907         BUG_ON(ret);
1908         return 0;
1909 }
1910
1911 static int update_block_group(struct btrfs_trans_handle *trans,
1912                               struct btrfs_root *root,
1913                               u64 bytenr, u64 num_bytes, int alloc,
1914                               int mark_free)
1915 {
1916         struct btrfs_block_group_cache *cache;
1917         struct btrfs_fs_info *info = root->fs_info;
1918         u64 total = num_bytes;
1919         u64 old_val;
1920         u64 byte_in_group;
1921         u64 start;
1922         u64 end;
1923
1924         /* block accounting for super block */
1925         old_val = btrfs_super_bytes_used(info->super_copy);
1926         if (alloc)
1927                 old_val += num_bytes;
1928         else
1929                 old_val -= num_bytes;
1930         btrfs_set_super_bytes_used(info->super_copy, old_val);
1931
1932         /* block accounting for root item */
1933         old_val = btrfs_root_used(&root->root_item);
1934         if (alloc)
1935                 old_val += num_bytes;
1936         else
1937                 old_val -= num_bytes;
1938         btrfs_set_root_used(&root->root_item, old_val);
1939
1940         while(total) {
1941                 cache = btrfs_lookup_block_group(info, bytenr);
1942                 if (!cache) {
1943                         return -1;
1944                 }
1945                 byte_in_group = bytenr - cache->key.objectid;
1946                 WARN_ON(byte_in_group > cache->key.offset);
1947                 start = cache->key.objectid;
1948                 end = start + cache->key.offset - 1;
1949                 set_extent_bits(&info->block_group_cache, start, end,
1950                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1951
1952                 old_val = btrfs_block_group_used(&cache->item);
1953                 num_bytes = min(total, cache->key.offset - byte_in_group);
1954
1955                 if (alloc) {
1956                         old_val += num_bytes;
1957                         cache->space_info->bytes_used += num_bytes;
1958                 } else {
1959                         old_val -= num_bytes;
1960                         cache->space_info->bytes_used -= num_bytes;
1961                         if (mark_free) {
1962                                 set_extent_dirty(&info->free_space_cache,
1963                                                  bytenr, bytenr + num_bytes - 1,
1964                                                  GFP_NOFS);
1965                         }
1966                 }
1967                 btrfs_set_block_group_used(&cache->item, old_val);
1968                 total -= num_bytes;
1969                 bytenr += num_bytes;
1970         }
1971         return 0;
1972 }
1973
1974 static int update_pinned_extents(struct btrfs_root *root,
1975                                 u64 bytenr, u64 num, int pin)
1976 {
1977         u64 len;
1978         struct btrfs_block_group_cache *cache;
1979         struct btrfs_fs_info *fs_info = root->fs_info;
1980
1981         if (pin) {
1982                 set_extent_dirty(&fs_info->pinned_extents,
1983                                 bytenr, bytenr + num - 1, GFP_NOFS);
1984         } else {
1985                 clear_extent_dirty(&fs_info->pinned_extents,
1986                                 bytenr, bytenr + num - 1, GFP_NOFS);
1987         }
1988         while (num > 0) {
1989                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1990                 if (!cache) {
1991                         len = min((u64)root->sectorsize, num);
1992                         goto next;
1993                 }
1994                 WARN_ON(!cache);
1995                 len = min(num, cache->key.offset -
1996                           (bytenr - cache->key.objectid));
1997                 if (pin) {
1998                         cache->pinned += len;
1999                         cache->space_info->bytes_pinned += len;
2000                         fs_info->total_pinned += len;
2001                 } else {
2002                         cache->pinned -= len;
2003                         cache->space_info->bytes_pinned -= len;
2004                         fs_info->total_pinned -= len;
2005                 }
2006 next:
2007                 bytenr += len;
2008                 num -= len;
2009         }
2010         return 0;
2011 }
2012
2013 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
2014 {
2015         u64 last = 0;
2016         u64 start;
2017         u64 end;
2018         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
2019         int ret;
2020
2021         while(1) {
2022                 ret = find_first_extent_bit(pinned_extents, last,
2023                                             &start, &end, EXTENT_DIRTY);
2024                 if (ret)
2025                         break;
2026                 set_extent_dirty(copy, start, end, GFP_NOFS);
2027                 last = end + 1;
2028         }
2029         return 0;
2030 }
2031
2032 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
2033                                struct btrfs_root *root,
2034                                struct extent_io_tree *unpin)
2035 {
2036         u64 start;
2037         u64 end;
2038         int ret;
2039         struct extent_io_tree *free_space_cache;
2040         free_space_cache = &root->fs_info->free_space_cache;
2041
2042         while(1) {
2043                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2044                                             EXTENT_DIRTY);
2045                 if (ret)
2046                         break;
2047                 update_pinned_extents(root, start, end + 1 - start, 0);
2048                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
2049                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
2050         }
2051         return 0;
2052 }
2053
2054 static int extent_root_pending_ops(struct btrfs_fs_info *info)
2055 {
2056         u64 start;
2057         u64 end;
2058         int ret;
2059
2060         ret = find_first_extent_bit(&info->extent_ins, 0, &start,
2061                                     &end, EXTENT_LOCKED);
2062         if (!ret) {
2063                 ret = find_first_extent_bit(&info->pending_del, 0, &start, &end,
2064                                             EXTENT_LOCKED);
2065         }
2066         return ret == 0;
2067
2068 }
2069 static int finish_current_insert(struct btrfs_trans_handle *trans,
2070                                  struct btrfs_root *extent_root)
2071 {
2072         u64 start;
2073         u64 end;
2074         u64 priv;
2075         struct btrfs_fs_info *info = extent_root->fs_info;
2076         struct btrfs_path *path;
2077         struct pending_extent_op *extent_op;
2078         struct btrfs_key key;
2079         int ret;
2080         int skinny_metadata =
2081                 btrfs_fs_incompat(extent_root->fs_info,
2082                                   BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
2083
2084         path = btrfs_alloc_path();
2085
2086         while(1) {
2087                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
2088                                             &end, EXTENT_LOCKED);
2089                 if (ret)
2090                         break;
2091
2092                 ret = get_state_private(&info->extent_ins, start, &priv);
2093                 BUG_ON(ret);
2094                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2095
2096                 if (extent_op->type == PENDING_EXTENT_INSERT) {
2097                         key.objectid = start;
2098                         if (skinny_metadata) {
2099                                 key.offset = extent_op->level;
2100                                 key.type = BTRFS_METADATA_ITEM_KEY;
2101                         } else {
2102                                 key.offset = extent_op->num_bytes;
2103                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2104                         }
2105                         ret = alloc_reserved_tree_block(trans, extent_root,
2106                                                 extent_root->root_key.objectid,
2107                                                 trans->transid,
2108                                                 extent_op->flags,
2109                                                 &extent_op->key,
2110                                                 extent_op->level, &key);
2111                         BUG_ON(ret);
2112                 } else {
2113                         BUG_ON(1);
2114                 }
2115
2116                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
2117                                   GFP_NOFS);
2118                 kfree(extent_op);
2119         }
2120         btrfs_free_path(path);
2121         return 0;
2122 }
2123
2124 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2125                           struct btrfs_root *root,
2126                           u64 bytenr, u64 num_bytes, int is_data)
2127 {
2128         int err = 0;
2129         struct extent_buffer *buf;
2130
2131         if (is_data)
2132                 goto pinit;
2133
2134         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2135         if (!buf)
2136                 goto pinit;
2137
2138         /* we can reuse a block if it hasn't been written
2139          * and it is from this transaction.  We can't
2140          * reuse anything from the tree log root because
2141          * it has tiny sub-transactions.
2142          */
2143         if (btrfs_buffer_uptodate(buf, 0)) {
2144                 u64 header_owner = btrfs_header_owner(buf);
2145                 u64 header_transid = btrfs_header_generation(buf);
2146                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2147                     header_transid == trans->transid &&
2148                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2149                         clean_tree_block(NULL, root, buf);
2150                         free_extent_buffer(buf);
2151                         return 1;
2152                 }
2153         }
2154         free_extent_buffer(buf);
2155 pinit:
2156         update_pinned_extents(root, bytenr, num_bytes, 1);
2157
2158         BUG_ON(err < 0);
2159         return 0;
2160 }
2161
2162 void btrfs_pin_extent(struct btrfs_fs_info *fs_info,
2163                        u64 bytenr, u64 num_bytes)
2164 {
2165         update_pinned_extents(fs_info->extent_root, bytenr, num_bytes, 1);
2166 }
2167
2168 void btrfs_unpin_extent(struct btrfs_fs_info *fs_info,
2169                         u64 bytenr, u64 num_bytes)
2170 {
2171         update_pinned_extents(fs_info->extent_root, bytenr, num_bytes, 0);
2172 }
2173
2174 /*
2175  * remove an extent from the root, returns 0 on success
2176  */
2177 static int __free_extent(struct btrfs_trans_handle *trans,
2178                          struct btrfs_root *root,
2179                          u64 bytenr, u64 num_bytes, u64 parent,
2180                          u64 root_objectid, u64 owner_objectid,
2181                          u64 owner_offset, int refs_to_drop)
2182 {
2183
2184         struct btrfs_key key;
2185         struct btrfs_path *path;
2186         struct btrfs_extent_ops *ops = root->fs_info->extent_ops;
2187         struct btrfs_root *extent_root = root->fs_info->extent_root;
2188         struct extent_buffer *leaf;
2189         struct btrfs_extent_item *ei;
2190         struct btrfs_extent_inline_ref *iref;
2191         int ret;
2192         int is_data;
2193         int extent_slot = 0;
2194         int found_extent = 0;
2195         int num_to_del = 1;
2196         u32 item_size;
2197         u64 refs;
2198         int skinny_metadata =
2199                 btrfs_fs_incompat(extent_root->fs_info,
2200                                   BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
2201
2202         if (root->fs_info->free_extent_hook) {
2203                 root->fs_info->free_extent_hook(trans, root, bytenr, num_bytes,
2204                                                 parent, root_objectid, owner_objectid,
2205                                                 owner_offset, refs_to_drop);
2206
2207         }
2208         path = btrfs_alloc_path();
2209         if (!path)
2210                 return -ENOMEM;
2211
2212         path->reada = 1;
2213         path->leave_spinning = 1;
2214
2215         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2216         if (is_data)
2217                 skinny_metadata = 0;
2218         BUG_ON(!is_data && refs_to_drop != 1);
2219
2220         ret = lookup_extent_backref(trans, extent_root, path, &iref,
2221                                     bytenr, num_bytes, parent,
2222                                     root_objectid, owner_objectid,
2223                                     owner_offset);
2224         if (ret == 0) {
2225                 extent_slot = path->slots[0];
2226                 while (extent_slot >= 0) {
2227                         btrfs_item_key_to_cpu(path->nodes[0], &key,
2228                                               extent_slot);
2229                         if (key.objectid != bytenr)
2230                                 break;
2231                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2232                             key.offset == num_bytes) {
2233                                 found_extent = 1;
2234                                 break;
2235                         }
2236                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
2237                             key.offset == owner_objectid) {
2238                                 found_extent = 1;
2239                                 break;
2240                         }
2241                         if (path->slots[0] - extent_slot > 5)
2242                                 break;
2243                         extent_slot--;
2244                 }
2245 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2246                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
2247                 if (found_extent && item_size < sizeof(*ei))
2248                         found_extent = 0;
2249 #endif
2250                 if (!found_extent) {
2251                         BUG_ON(iref);
2252                         ret = remove_extent_backref(trans, extent_root, path,
2253                                                     NULL, refs_to_drop,
2254                                                     is_data);
2255                         BUG_ON(ret);
2256                         btrfs_release_path(extent_root, path);
2257                         path->leave_spinning = 1;
2258
2259                         key.objectid = bytenr;
2260
2261                         if (skinny_metadata) {
2262                                 key.type = BTRFS_METADATA_ITEM_KEY;
2263                                 key.offset = owner_objectid;
2264                         } else {
2265                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2266                                 key.offset = num_bytes;
2267                         }
2268
2269                         ret = btrfs_search_slot(trans, extent_root,
2270                                                 &key, path, -1, 1);
2271                         if (ret > 0 && skinny_metadata && path->slots[0]) {
2272                                 path->slots[0]--;
2273                                 btrfs_item_key_to_cpu(path->nodes[0],
2274                                                       &key,
2275                                                       path->slots[0]);
2276                                 if (key.objectid == bytenr &&
2277                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2278                                     key.offset == num_bytes)
2279                                         ret = 0;
2280                         }
2281
2282                         if (ret > 0 && skinny_metadata) {
2283                                 skinny_metadata = 0;
2284                                 btrfs_release_path(extent_root, path);
2285                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2286                                 key.offset = num_bytes;
2287                                 ret = btrfs_search_slot(trans, extent_root,
2288                                                         &key, path, -1, 1);
2289                         }
2290
2291                         if (ret) {
2292                                 printk(KERN_ERR "umm, got %d back from search"
2293                                        ", was looking for %llu\n", ret,
2294                                        (unsigned long long)bytenr);
2295                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2296                         }
2297                         BUG_ON(ret);
2298                         extent_slot = path->slots[0];
2299                 }
2300         } else {
2301                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2302                        "parent %llu root %llu  owner %llu offset %llu\n",
2303                        (unsigned long long)bytenr,
2304                        (unsigned long long)parent,
2305                        (unsigned long long)root_objectid,
2306                        (unsigned long long)owner_objectid,
2307                        (unsigned long long)owner_offset);
2308                 ret = -EIO;
2309                 goto fail;
2310         }
2311
2312         leaf = path->nodes[0];
2313         item_size = btrfs_item_size_nr(leaf, extent_slot);
2314 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2315         if (item_size < sizeof(*ei)) {
2316                 BUG_ON(found_extent || extent_slot != path->slots[0]);
2317                 ret = convert_extent_item_v0(trans, extent_root, path,
2318                                              owner_objectid, 0);
2319                 BUG_ON(ret < 0);
2320
2321                 btrfs_release_path(extent_root, path);
2322                 path->leave_spinning = 1;
2323
2324                 key.objectid = bytenr;
2325                 key.type = BTRFS_EXTENT_ITEM_KEY;
2326                 key.offset = num_bytes;
2327
2328                 ret = btrfs_search_slot(trans, extent_root, &key, path,
2329                                         -1, 1);
2330                 if (ret) {
2331                         printk(KERN_ERR "umm, got %d back from search"
2332                                ", was looking for %llu\n", ret,
2333                                (unsigned long long)bytenr);
2334                         btrfs_print_leaf(extent_root, path->nodes[0]);
2335                 }
2336                 BUG_ON(ret);
2337                 extent_slot = path->slots[0];
2338                 leaf = path->nodes[0];
2339                 item_size = btrfs_item_size_nr(leaf, extent_slot);
2340         }
2341 #endif
2342         BUG_ON(item_size < sizeof(*ei));
2343         ei = btrfs_item_ptr(leaf, extent_slot,
2344                             struct btrfs_extent_item);
2345         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
2346             key.type == BTRFS_EXTENT_ITEM_KEY) {
2347                 struct btrfs_tree_block_info *bi;
2348                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
2349                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2350                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
2351         }
2352
2353         refs = btrfs_extent_refs(leaf, ei);
2354         BUG_ON(refs < refs_to_drop);
2355         refs -= refs_to_drop;
2356
2357         if (refs > 0) {
2358                 /*
2359                  * In the case of inline back ref, reference count will
2360                  * be updated by remove_extent_backref
2361                  */
2362                 if (iref) {
2363                         BUG_ON(!found_extent);
2364                 } else {
2365                         btrfs_set_extent_refs(leaf, ei, refs);
2366                         btrfs_mark_buffer_dirty(leaf);
2367                 }
2368                 if (found_extent) {
2369                         ret = remove_extent_backref(trans, extent_root, path,
2370                                                     iref, refs_to_drop,
2371                                                     is_data);
2372                         BUG_ON(ret);
2373                 }
2374         } else {
2375                 int mark_free = 0;
2376                 int pin = 1;
2377
2378                 if (found_extent) {
2379                         BUG_ON(is_data && refs_to_drop !=
2380                                extent_data_ref_count(root, path, iref));
2381                         if (iref) {
2382                                 BUG_ON(path->slots[0] != extent_slot);
2383                         } else {
2384                                 BUG_ON(path->slots[0] != extent_slot + 1);
2385                                 path->slots[0] = extent_slot;
2386                                 num_to_del = 2;
2387                         }
2388                 }
2389
2390                 if (ops && ops->free_extent) {
2391                         ret = ops->free_extent(root, bytenr, num_bytes);
2392                         if (ret > 0) {
2393                                 pin = 0;
2394                                 mark_free = 0;
2395                         }
2396                 }
2397
2398                 if (pin) {
2399                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
2400                                              is_data);
2401                         if (ret > 0)
2402                                 mark_free = 1;
2403                         BUG_ON(ret < 0);
2404                 }
2405
2406                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2407                                       num_to_del);
2408                 BUG_ON(ret);
2409                 btrfs_release_path(extent_root, path);
2410
2411                 if (is_data) {
2412                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2413                         BUG_ON(ret);
2414                 }
2415
2416                 update_block_group(trans, root, bytenr, num_bytes, 0, mark_free);
2417         }
2418 fail:
2419         btrfs_free_path(path);
2420         finish_current_insert(trans, extent_root);
2421         return ret;
2422 }
2423
2424 /*
2425  * find all the blocks marked as pending in the radix tree and remove
2426  * them from the extent map
2427  */
2428 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
2429                                btrfs_root *extent_root)
2430 {
2431         int ret;
2432         int err = 0;
2433         u64 start;
2434         u64 end;
2435         u64 priv;
2436         struct extent_io_tree *pending_del;
2437         struct extent_io_tree *extent_ins;
2438         struct pending_extent_op *extent_op;
2439
2440         extent_ins = &extent_root->fs_info->extent_ins;
2441         pending_del = &extent_root->fs_info->pending_del;
2442
2443         while(1) {
2444                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
2445                                             EXTENT_LOCKED);
2446                 if (ret)
2447                         break;
2448
2449                 ret = get_state_private(pending_del, start, &priv);
2450                 BUG_ON(ret);
2451                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2452
2453                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
2454                                   GFP_NOFS);
2455
2456                 if (!test_range_bit(extent_ins, start, end,
2457                                     EXTENT_LOCKED, 0)) {
2458                         ret = __free_extent(trans, extent_root,
2459                                             start, end + 1 - start, 0,
2460                                             extent_root->root_key.objectid,
2461                                             extent_op->level, 0, 1);
2462                         kfree(extent_op);
2463                 } else {
2464                         kfree(extent_op);
2465                         ret = get_state_private(extent_ins, start, &priv);
2466                         BUG_ON(ret);
2467                         extent_op = (struct pending_extent_op *)
2468                                                         (unsigned long)priv;
2469
2470                         clear_extent_bits(extent_ins, start, end,
2471                                           EXTENT_LOCKED, GFP_NOFS);
2472
2473                         if (extent_op->type == PENDING_BACKREF_UPDATE)
2474                                 BUG_ON(1);
2475
2476                         kfree(extent_op);
2477                 }
2478                 if (ret)
2479                         err = ret;
2480         }
2481         return err;
2482 }
2483
2484 /*
2485  * remove an extent from the root, returns 0 on success
2486  */
2487
2488 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2489                       struct btrfs_root *root,
2490                       u64 bytenr, u64 num_bytes, u64 parent,
2491                       u64 root_objectid, u64 owner, u64 offset)
2492 {
2493         struct btrfs_root *extent_root = root->fs_info->extent_root;
2494         int pending_ret;
2495         int ret;
2496
2497         WARN_ON(num_bytes < root->sectorsize);
2498         if (root == extent_root) {
2499                 struct pending_extent_op *extent_op;
2500
2501                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2502                 BUG_ON(!extent_op);
2503
2504                 extent_op->type = PENDING_EXTENT_DELETE;
2505                 extent_op->bytenr = bytenr;
2506                 extent_op->num_bytes = num_bytes;
2507                 extent_op->level = (int)owner;
2508
2509                 set_extent_bits(&root->fs_info->pending_del,
2510                                 bytenr, bytenr + num_bytes - 1,
2511                                 EXTENT_LOCKED, GFP_NOFS);
2512                 set_state_private(&root->fs_info->pending_del,
2513                                   bytenr, (unsigned long)extent_op);
2514                 return 0;
2515         }
2516         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2517                             root_objectid, owner, offset, 1);
2518         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
2519         return ret ? ret : pending_ret;
2520 }
2521
2522 static u64 stripe_align(struct btrfs_root *root, u64 val)
2523 {
2524         u64 mask = ((u64)root->stripesize - 1);
2525         u64 ret = (val + mask) & ~mask;
2526         return ret;
2527 }
2528
2529 /*
2530  * walks the btree of allocated extents and find a hole of a given size.
2531  * The key ins is changed to record the hole:
2532  * ins->objectid == block start
2533  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2534  * ins->offset == number of blocks
2535  * Any available blocks before search_start are skipped.
2536  */
2537 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
2538                                      struct btrfs_root *orig_root,
2539                                      u64 num_bytes, u64 empty_size,
2540                                      u64 search_start, u64 search_end,
2541                                      u64 hint_byte, struct btrfs_key *ins,
2542                                      u64 exclude_start, u64 exclude_nr,
2543                                      int data)
2544 {
2545         int ret;
2546         u64 orig_search_start = search_start;
2547         struct btrfs_root * root = orig_root->fs_info->extent_root;
2548         struct btrfs_fs_info *info = root->fs_info;
2549         u64 total_needed = num_bytes;
2550         struct btrfs_block_group_cache *block_group;
2551         int full_scan = 0;
2552         int wrapped = 0;
2553
2554         WARN_ON(num_bytes < root->sectorsize);
2555         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2556
2557         search_start = stripe_align(root, search_start);
2558
2559         if (hint_byte) {
2560                 block_group = btrfs_lookup_first_block_group(info, hint_byte);
2561                 if (!block_group)
2562                         hint_byte = search_start;
2563                 block_group = btrfs_find_block_group(root, block_group,
2564                                                      hint_byte, data, 1);
2565         } else {
2566                 block_group = btrfs_find_block_group(root,
2567                                                      trans->block_group,
2568                                                      search_start, data, 1);
2569         }
2570
2571         total_needed += empty_size;
2572
2573 check_failed:
2574         search_start = stripe_align(root, search_start);
2575         if (!block_group) {
2576                 block_group = btrfs_lookup_first_block_group(info,
2577                                                              search_start);
2578                 if (!block_group)
2579                         block_group = btrfs_lookup_first_block_group(info,
2580                                                        orig_search_start);
2581         }
2582         ret = find_search_start(root, &block_group, &search_start,
2583                                 total_needed, data);
2584         if (ret)
2585                 goto new_group;
2586
2587         ins->objectid = search_start;
2588         ins->offset = num_bytes;
2589
2590         if (ins->objectid + num_bytes >
2591             block_group->key.objectid + block_group->key.offset) {
2592                 search_start = block_group->key.objectid +
2593                         block_group->key.offset;
2594                 goto new_group;
2595         }
2596
2597         if (test_range_bit(&info->extent_ins, ins->objectid,
2598                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
2599                 search_start = ins->objectid + num_bytes;
2600                 goto new_group;
2601         }
2602
2603         if (test_range_bit(&info->pinned_extents, ins->objectid,
2604                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
2605                 search_start = ins->objectid + num_bytes;
2606                 goto new_group;
2607         }
2608
2609         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
2610             ins->objectid < exclude_start + exclude_nr)) {
2611                 search_start = exclude_start + exclude_nr;
2612                 goto new_group;
2613         }
2614
2615         if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
2616                 block_group = btrfs_lookup_block_group(info, ins->objectid);
2617                 if (block_group)
2618                         trans->block_group = block_group;
2619         }
2620         ins->offset = num_bytes;
2621         return 0;
2622
2623 new_group:
2624         block_group = btrfs_lookup_first_block_group(info, search_start);
2625         if (!block_group) {
2626                 search_start = orig_search_start;
2627                 if (full_scan) {
2628                         ret = -ENOSPC;
2629                         goto error;
2630                 }
2631                 if (wrapped) {
2632                         if (!full_scan)
2633                                 total_needed -= empty_size;
2634                         full_scan = 1;
2635                 } else
2636                         wrapped = 1;
2637         }
2638         cond_resched();
2639         block_group = btrfs_find_block_group(root, block_group,
2640                                              search_start, data, 0);
2641         goto check_failed;
2642
2643 error:
2644         return ret;
2645 }
2646
2647 static int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2648                                 struct btrfs_root *root,
2649                                 u64 num_bytes, u64 empty_size,
2650                                 u64 hint_byte, u64 search_end,
2651                                 struct btrfs_key *ins, int data)
2652 {
2653         int ret;
2654         u64 search_start = 0;
2655         u64 alloc_profile;
2656         struct btrfs_fs_info *info = root->fs_info;
2657
2658         if (info->extent_ops) {
2659                 struct btrfs_extent_ops *ops = info->extent_ops;
2660                 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
2661                 BUG_ON(ret);
2662                 goto found;
2663         }
2664
2665         if (data) {
2666                 alloc_profile = info->avail_data_alloc_bits &
2667                                 info->data_alloc_profile;
2668                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2669         } else if ((info->system_allocs > 0 || root == info->chunk_root) &&
2670                    info->system_allocs >= 0) {
2671                 alloc_profile = info->avail_system_alloc_bits &
2672                                 info->system_alloc_profile;
2673                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2674         } else {
2675                 alloc_profile = info->avail_metadata_alloc_bits &
2676                                 info->metadata_alloc_profile;
2677                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2678         }
2679
2680         if (root->ref_cows) {
2681                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2682                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2683                                              num_bytes,
2684                                              BTRFS_BLOCK_GROUP_METADATA);
2685                         BUG_ON(ret);
2686                 }
2687                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2688                                      num_bytes + 2 * 1024 * 1024, data);
2689                 BUG_ON(ret);
2690         }
2691
2692         WARN_ON(num_bytes < root->sectorsize);
2693         ret = find_free_extent(trans, root, num_bytes, empty_size,
2694                                search_start, search_end, hint_byte, ins,
2695                                trans->alloc_exclude_start,
2696                                trans->alloc_exclude_nr, data);
2697         BUG_ON(ret);
2698 found:
2699         clear_extent_dirty(&root->fs_info->free_space_cache,
2700                            ins->objectid, ins->objectid + ins->offset - 1,
2701                            GFP_NOFS);
2702         return ret;
2703 }
2704
2705 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
2706                                      struct btrfs_root *root,
2707                                      u64 root_objectid, u64 generation,
2708                                      u64 flags, struct btrfs_disk_key *key,
2709                                      int level, struct btrfs_key *ins)
2710 {
2711         int ret;
2712         struct btrfs_fs_info *fs_info = root->fs_info;
2713         struct btrfs_extent_item *extent_item;
2714         struct btrfs_tree_block_info *block_info;
2715         struct btrfs_extent_inline_ref *iref;
2716         struct btrfs_path *path;
2717         struct extent_buffer *leaf;
2718         u32 size = sizeof(*extent_item) + sizeof(*iref);
2719         int skinny_metadata =
2720                 btrfs_fs_incompat(fs_info,
2721                                   BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
2722
2723         if (!skinny_metadata)
2724                 size += sizeof(*block_info);
2725
2726         path = btrfs_alloc_path();
2727         BUG_ON(!path);
2728
2729         path->leave_spinning = 1;
2730         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
2731                                       ins, size);
2732         BUG_ON(ret);
2733
2734         leaf = path->nodes[0];
2735         extent_item = btrfs_item_ptr(leaf, path->slots[0],
2736                                      struct btrfs_extent_item);
2737         btrfs_set_extent_refs(leaf, extent_item, 1);
2738         btrfs_set_extent_generation(leaf, extent_item, generation);
2739         btrfs_set_extent_flags(leaf, extent_item,
2740                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
2741
2742         if (skinny_metadata) {
2743                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
2744         } else {
2745                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
2746                 btrfs_set_tree_block_key(leaf, block_info, key);
2747                 btrfs_set_tree_block_level(leaf, block_info, level);
2748                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
2749         }
2750
2751         btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY);
2752         btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
2753
2754         btrfs_mark_buffer_dirty(leaf);
2755         btrfs_free_path(path);
2756
2757         ret = update_block_group(trans, root, ins->objectid, root->leafsize,
2758                                  1, 0);
2759         return ret;
2760 }
2761
2762 static int alloc_tree_block(struct btrfs_trans_handle *trans,
2763                             struct btrfs_root *root, u64 num_bytes,
2764                             u64 root_objectid, u64 generation,
2765                             u64 flags, struct btrfs_disk_key *key,
2766                             int level, u64 empty_size, u64 hint_byte,
2767                             u64 search_end, struct btrfs_key *ins)
2768 {
2769         int ret;
2770         ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
2771                                    hint_byte, search_end, ins, 0);
2772         BUG_ON(ret);
2773
2774         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID) {
2775                 struct pending_extent_op *extent_op;
2776
2777                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2778                 BUG_ON(!extent_op);
2779
2780                 extent_op->type = PENDING_EXTENT_INSERT;
2781                 extent_op->bytenr = ins->objectid;
2782                 extent_op->num_bytes = ins->offset;
2783                 extent_op->level = level;
2784                 extent_op->flags = flags;
2785                 memcpy(&extent_op->key, key, sizeof(*key));
2786
2787                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2788                                 ins->objectid + ins->offset - 1,
2789                                 EXTENT_LOCKED, GFP_NOFS);
2790                 set_state_private(&root->fs_info->extent_ins,
2791                                   ins->objectid, (unsigned long)extent_op);
2792         } else {
2793                 if (btrfs_fs_incompat(root->fs_info,
2794                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)) {
2795                         ins->offset = level;
2796                         ins->type = BTRFS_METADATA_ITEM_KEY;
2797                 }
2798                 ret = alloc_reserved_tree_block(trans, root, root_objectid,
2799                                                 generation, flags,
2800                                                 key, level, ins);
2801                 finish_current_insert(trans, root->fs_info->extent_root);
2802                 del_pending_extents(trans, root->fs_info->extent_root);
2803         }
2804         return ret;
2805 }
2806
2807 /*
2808  * helper function to allocate a block for a given tree
2809  * returns the tree buffer or NULL.
2810  */
2811 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2812                                         struct btrfs_root *root,
2813                                         u32 blocksize, u64 root_objectid,
2814                                         struct btrfs_disk_key *key, int level,
2815                                         u64 hint, u64 empty_size)
2816 {
2817         struct btrfs_key ins;
2818         int ret;
2819         struct extent_buffer *buf;
2820
2821         ret = alloc_tree_block(trans, root, blocksize, root_objectid,
2822                                trans->transid, 0, key, level,
2823                                empty_size, hint, (u64)-1, &ins);
2824         if (ret) {
2825                 BUG_ON(ret > 0);
2826                 return ERR_PTR(ret);
2827         }
2828
2829         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2830         if (!buf) {
2831                 btrfs_free_extent(trans, root, ins.objectid, ins.offset,
2832                                   0, root->root_key.objectid, level, 0);
2833                 BUG_ON(1);
2834                 return ERR_PTR(-ENOMEM);
2835         }
2836         btrfs_set_buffer_uptodate(buf);
2837         trans->blocks_used++;
2838
2839         return buf;
2840 }
2841
2842 #if 0
2843
2844 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2845                                   struct btrfs_root *root,
2846                                   struct extent_buffer *leaf)
2847 {
2848         u64 leaf_owner;
2849         u64 leaf_generation;
2850         struct btrfs_key key;
2851         struct btrfs_file_extent_item *fi;
2852         int i;
2853         int nritems;
2854         int ret;
2855
2856         BUG_ON(!btrfs_is_leaf(leaf));
2857         nritems = btrfs_header_nritems(leaf);
2858         leaf_owner = btrfs_header_owner(leaf);
2859         leaf_generation = btrfs_header_generation(leaf);
2860
2861         for (i = 0; i < nritems; i++) {
2862                 u64 disk_bytenr;
2863
2864                 btrfs_item_key_to_cpu(leaf, &key, i);
2865                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2866                         continue;
2867                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2868                 if (btrfs_file_extent_type(leaf, fi) ==
2869                     BTRFS_FILE_EXTENT_INLINE)
2870                         continue;
2871                 /*
2872                  * FIXME make sure to insert a trans record that
2873                  * repeats the snapshot del on crash
2874                  */
2875                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2876                 if (disk_bytenr == 0)
2877                         continue;
2878                 ret = btrfs_free_extent(trans, root, disk_bytenr,
2879                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2880                                 leaf->start, leaf_owner, leaf_generation,
2881                                 key.objectid, 0);
2882                 BUG_ON(ret);
2883         }
2884         return 0;
2885 }
2886
2887 static void noinline reada_walk_down(struct btrfs_root *root,
2888                                      struct extent_buffer *node,
2889                                      int slot)
2890 {
2891         u64 bytenr;
2892         u64 last = 0;
2893         u32 nritems;
2894         u32 refs;
2895         u32 blocksize;
2896         int ret;
2897         int i;
2898         int level;
2899         int skipped = 0;
2900
2901         nritems = btrfs_header_nritems(node);
2902         level = btrfs_header_level(node);
2903         if (level)
2904                 return;
2905
2906         for (i = slot; i < nritems && skipped < 32; i++) {
2907                 bytenr = btrfs_node_blockptr(node, i);
2908                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2909                              (last > bytenr && last - bytenr > 32 * 1024))) {
2910                         skipped++;
2911                         continue;
2912                 }
2913                 blocksize = btrfs_level_size(root, level - 1);
2914                 if (i != slot) {
2915                         ret = btrfs_lookup_extent_ref(NULL, root, bytenr,
2916                                                       blocksize, &refs);
2917                         BUG_ON(ret);
2918                         if (refs != 1) {
2919                                 skipped++;
2920                                 continue;
2921                         }
2922                 }
2923                 mutex_unlock(&root->fs_info->fs_mutex);
2924                 ret = readahead_tree_block(root, bytenr, blocksize,
2925                                            btrfs_node_ptr_generation(node, i));
2926                 last = bytenr + blocksize;
2927                 cond_resched();
2928                 mutex_lock(&root->fs_info->fs_mutex);
2929                 if (ret)
2930                         break;
2931         }
2932 }
2933
2934 /*
2935  * helper function for drop_snapshot, this walks down the tree dropping ref
2936  * counts as it goes.
2937  */
2938 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2939                                    struct btrfs_root *root,
2940                                    struct btrfs_path *path, int *level)
2941 {
2942         u64 root_owner;
2943         u64 root_gen;
2944         u64 bytenr;
2945         u64 ptr_gen;
2946         struct extent_buffer *next;
2947         struct extent_buffer *cur;
2948         struct extent_buffer *parent;
2949         u32 blocksize;
2950         int ret;
2951         u32 refs;
2952
2953         WARN_ON(*level < 0);
2954         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2955         ret = btrfs_lookup_extent_ref(trans, root,
2956                                       path->nodes[*level]->start,
2957                                       path->nodes[*level]->len, &refs);
2958         BUG_ON(ret);
2959         if (refs > 1)
2960                 goto out;
2961
2962         /*
2963          * walk down to the last node level and free all the leaves
2964          */
2965         while(*level >= 0) {
2966                 WARN_ON(*level < 0);
2967                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2968                 cur = path->nodes[*level];
2969
2970                 if (btrfs_header_level(cur) != *level)
2971                         WARN_ON(1);
2972
2973                 if (path->slots[*level] >=
2974                     btrfs_header_nritems(cur))
2975                         break;
2976                 if (*level == 0) {
2977                         ret = drop_leaf_ref(trans, root, cur);
2978                         BUG_ON(ret);
2979                         break;
2980                 }
2981                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2982                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2983                 blocksize = btrfs_level_size(root, *level - 1);
2984                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
2985                                               &refs);
2986                 BUG_ON(ret);
2987                 if (refs != 1) {
2988                         parent = path->nodes[*level];
2989                         root_owner = btrfs_header_owner(parent);
2990                         root_gen = btrfs_header_generation(parent);
2991                         path->slots[*level]++;
2992                         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
2993                                                 parent->start, root_owner,
2994                                                 root_gen, *level - 1, 1);
2995                         BUG_ON(ret);
2996                         continue;
2997                 }
2998                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2999                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
3000                         free_extent_buffer(next);
3001                         reada_walk_down(root, cur, path->slots[*level]);
3002                         mutex_unlock(&root->fs_info->fs_mutex);
3003                         next = read_tree_block(root, bytenr, blocksize,
3004                                                ptr_gen);
3005                         mutex_lock(&root->fs_info->fs_mutex);
3006                 }
3007                 WARN_ON(*level <= 0);
3008                 if (path->nodes[*level-1])
3009                         free_extent_buffer(path->nodes[*level-1]);
3010                 path->nodes[*level-1] = next;
3011                 *level = btrfs_header_level(next);
3012                 path->slots[*level] = 0;
3013         }
3014 out:
3015         WARN_ON(*level < 0);
3016         WARN_ON(*level >= BTRFS_MAX_LEVEL);
3017
3018         if (path->nodes[*level] == root->node) {
3019                 root_owner = root->root_key.objectid;
3020                 parent = path->nodes[*level];
3021         } else {
3022                 parent = path->nodes[*level + 1];
3023                 root_owner = btrfs_header_owner(parent);
3024         }
3025
3026         root_gen = btrfs_header_generation(parent);
3027         ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
3028                                 path->nodes[*level]->len, parent->start,
3029                                 root_owner, root_gen, *level, 1);
3030         free_extent_buffer(path->nodes[*level]);
3031         path->nodes[*level] = NULL;
3032         *level += 1;
3033         BUG_ON(ret);
3034         return 0;
3035 }
3036
3037 /*
3038  * helper for dropping snapshots.  This walks back up the tree in the path
3039  * to find the first node higher up where we haven't yet gone through
3040  * all the slots
3041  */
3042 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
3043                                  struct btrfs_root *root,
3044                                  struct btrfs_path *path, int *level)
3045 {
3046         u64 root_owner;
3047         u64 root_gen;
3048         struct btrfs_root_item *root_item = &root->root_item;
3049         int i;
3050         int slot;
3051         int ret;
3052
3053         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
3054                 slot = path->slots[i];
3055                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
3056                         struct extent_buffer *node;
3057                         struct btrfs_disk_key disk_key;
3058                         node = path->nodes[i];
3059                         path->slots[i]++;
3060                         *level = i;
3061                         WARN_ON(*level == 0);
3062                         btrfs_node_key(node, &disk_key, path->slots[i]);
3063                         memcpy(&root_item->drop_progress,
3064                                &disk_key, sizeof(disk_key));
3065                         root_item->drop_level = i;
3066                         return 0;
3067                 } else {
3068                         struct extent_buffer *parent;
3069                         if (path->nodes[*level] == root->node)
3070                                 parent = path->nodes[*level];
3071                         else
3072                                 parent = path->nodes[*level + 1];
3073
3074                         root_owner = btrfs_header_owner(parent);
3075                         root_gen = btrfs_header_generation(parent);
3076                         ret = btrfs_free_extent(trans, root,
3077                                                 path->nodes[*level]->start,
3078                                                 path->nodes[*level]->len,
3079                                                 parent->start, root_owner,
3080                                                 root_gen, *level, 1);
3081                         BUG_ON(ret);
3082                         free_extent_buffer(path->nodes[*level]);
3083                         path->nodes[*level] = NULL;
3084                         *level = i + 1;
3085                 }
3086         }
3087         return 1;
3088 }
3089
3090 #endif
3091
3092 int btrfs_free_block_groups(struct btrfs_fs_info *info)
3093 {
3094         struct btrfs_space_info *sinfo;
3095         struct btrfs_block_group_cache *cache;
3096         u64 start;
3097         u64 end;
3098         u64 ptr;
3099         int ret;
3100
3101         while(1) {
3102                 ret = find_first_extent_bit(&info->block_group_cache, 0,
3103                                             &start, &end, (unsigned int)-1);
3104                 if (ret)
3105                         break;
3106                 ret = get_state_private(&info->block_group_cache, start, &ptr);
3107                 if (!ret) {
3108                         cache = (struct btrfs_block_group_cache *)
3109                                         (uintptr_t)ptr;
3110                         if (cache->free_space_ctl) {
3111                                 btrfs_remove_free_space_cache(cache);
3112                                 kfree(cache->free_space_ctl);
3113                         }
3114                         kfree(cache);
3115                 }
3116                 clear_extent_bits(&info->block_group_cache, start,
3117                                   end, (unsigned int)-1, GFP_NOFS);
3118         }
3119         while(1) {
3120                 ret = find_first_extent_bit(&info->free_space_cache, 0,
3121                                             &start, &end, EXTENT_DIRTY);
3122                 if (ret)
3123                         break;
3124                 clear_extent_dirty(&info->free_space_cache, start,
3125                                    end, GFP_NOFS);
3126         }
3127
3128         while (!list_empty(&info->space_info)) {
3129                 sinfo = list_entry(info->space_info.next,
3130                                    struct btrfs_space_info, list);
3131                 list_del_init(&sinfo->list);
3132                 kfree(sinfo);
3133         }
3134         return 0;
3135 }
3136
3137 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3138                            struct btrfs_key *key)
3139 {
3140         int ret;
3141         struct btrfs_key found_key;
3142         struct extent_buffer *leaf;
3143         int slot;
3144
3145         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3146         if (ret < 0)
3147                 return ret;
3148         while(1) {
3149                 slot = path->slots[0];
3150                 leaf = path->nodes[0];
3151                 if (slot >= btrfs_header_nritems(leaf)) {
3152                         ret = btrfs_next_leaf(root, path);
3153                         if (ret == 0)
3154                                 continue;
3155                         if (ret < 0)
3156                                 goto error;
3157                         break;
3158                 }
3159                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3160
3161                 if (found_key.objectid >= key->objectid &&
3162                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
3163                         return 0;
3164                 path->slots[0]++;
3165         }
3166         ret = -ENOENT;
3167 error:
3168         return ret;
3169 }
3170
3171 int btrfs_read_block_groups(struct btrfs_root *root)
3172 {
3173         struct btrfs_path *path;
3174         int ret;
3175         int bit;
3176         struct btrfs_block_group_cache *cache;
3177         struct btrfs_fs_info *info = root->fs_info;
3178         struct btrfs_space_info *space_info;
3179         struct extent_io_tree *block_group_cache;
3180         struct btrfs_key key;
3181         struct btrfs_key found_key;
3182         struct extent_buffer *leaf;
3183
3184         block_group_cache = &info->block_group_cache;
3185
3186         root = info->extent_root;
3187         key.objectid = 0;
3188         key.offset = 0;
3189         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3190         path = btrfs_alloc_path();
3191         if (!path)
3192                 return -ENOMEM;
3193
3194         while(1) {
3195                 ret = find_first_block_group(root, path, &key);
3196                 if (ret > 0) {
3197                         ret = 0;
3198                         goto error;
3199                 }
3200                 if (ret != 0) {
3201                         goto error;
3202                 }
3203                 leaf = path->nodes[0];
3204                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3205                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3206                 if (!cache) {
3207                         ret = -ENOMEM;
3208                         break;
3209                 }
3210
3211                 read_extent_buffer(leaf, &cache->item,
3212                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
3213                                    sizeof(cache->item));
3214                 memcpy(&cache->key, &found_key, sizeof(found_key));
3215                 cache->cached = 0;
3216                 cache->pinned = 0;
3217                 key.objectid = found_key.objectid + found_key.offset;
3218                 btrfs_release_path(root, path);
3219                 cache->flags = btrfs_block_group_flags(&cache->item);
3220                 bit = 0;
3221                 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3222                         bit = BLOCK_GROUP_DATA;
3223                 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3224                         bit = BLOCK_GROUP_SYSTEM;
3225                 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3226                         bit = BLOCK_GROUP_METADATA;
3227                 }
3228                 set_avail_alloc_bits(info, cache->flags);
3229                 if (btrfs_chunk_readonly(root, cache->key.objectid))
3230                         cache->ro = 1;
3231
3232                 ret = update_space_info(info, cache->flags, found_key.offset,
3233                                         btrfs_block_group_used(&cache->item),
3234                                         &space_info);
3235                 BUG_ON(ret);
3236                 cache->space_info = space_info;
3237
3238                 /* use EXTENT_LOCKED to prevent merging */
3239                 set_extent_bits(block_group_cache, found_key.objectid,
3240                                 found_key.objectid + found_key.offset - 1,
3241                                 bit | EXTENT_LOCKED, GFP_NOFS);
3242                 set_state_private(block_group_cache, found_key.objectid,
3243                                   (unsigned long)cache);
3244         }
3245         ret = 0;
3246 error:
3247         btrfs_free_path(path);
3248         return ret;
3249 }
3250
3251 struct btrfs_block_group_cache *
3252 btrfs_add_block_group(struct btrfs_fs_info *fs_info, u64 bytes_used, u64 type,
3253                       u64 chunk_objectid, u64 chunk_offset, u64 size)
3254 {
3255         int ret;
3256         int bit = 0;
3257         struct btrfs_block_group_cache *cache;
3258         struct extent_io_tree *block_group_cache;
3259
3260         block_group_cache = &fs_info->block_group_cache;
3261
3262         cache = kzalloc(sizeof(*cache), GFP_NOFS);
3263         BUG_ON(!cache);
3264         cache->key.objectid = chunk_offset;
3265         cache->key.offset = size;
3266
3267         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3268         btrfs_set_block_group_used(&cache->item, bytes_used);
3269         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3270         cache->flags = type;
3271         btrfs_set_block_group_flags(&cache->item, type);
3272
3273         ret = update_space_info(fs_info, cache->flags, size, bytes_used,
3274                                 &cache->space_info);
3275         BUG_ON(ret);
3276
3277         bit = block_group_state_bits(type);
3278         ret = set_extent_bits(block_group_cache, chunk_offset,
3279                               chunk_offset + size - 1,
3280                               bit | EXTENT_LOCKED, GFP_NOFS);
3281         BUG_ON(ret);
3282
3283         ret = set_state_private(block_group_cache, chunk_offset,
3284                                 (unsigned long)cache);
3285         BUG_ON(ret);
3286         set_avail_alloc_bits(fs_info, type);
3287
3288         return cache;
3289 }
3290
3291 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3292                            struct btrfs_root *root, u64 bytes_used,
3293                            u64 type, u64 chunk_objectid, u64 chunk_offset,
3294                            u64 size)
3295 {
3296         int ret;
3297         struct btrfs_root *extent_root;
3298         struct btrfs_block_group_cache *cache;
3299
3300         cache = btrfs_add_block_group(root->fs_info, bytes_used, type,
3301                                       chunk_objectid, chunk_offset, size);
3302         extent_root = root->fs_info->extent_root;
3303         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3304                                 sizeof(cache->item));
3305         BUG_ON(ret);
3306
3307         ret = finish_current_insert(trans, extent_root);
3308         BUG_ON(ret);
3309         ret = del_pending_extents(trans, extent_root);
3310         BUG_ON(ret);
3311
3312         return 0;
3313 }
3314
3315 /*
3316  * This is for converter use only.
3317  *
3318  * In that case, we don't know where are free blocks located.
3319  * Therefore all block group cache entries must be setup properly
3320  * before doing any block allocation.
3321  */
3322 int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
3323                             struct btrfs_root *root)
3324 {
3325         u64 total_bytes;
3326         u64 cur_start;
3327         u64 group_type;
3328         u64 group_size;
3329         u64 group_align;
3330         u64 total_data = 0;
3331         u64 total_metadata = 0;
3332         u64 chunk_objectid;
3333         int ret;
3334         int bit;
3335         struct btrfs_root *extent_root;
3336         struct btrfs_block_group_cache *cache;
3337         struct extent_io_tree *block_group_cache;
3338
3339         extent_root = root->fs_info->extent_root;
3340         block_group_cache = &root->fs_info->block_group_cache;
3341         chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3342         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
3343         group_align = 64 * root->sectorsize;
3344
3345         cur_start = 0;
3346         while (cur_start < total_bytes) {
3347                 group_size = total_bytes / 12;
3348                 group_size = min_t(u64, group_size, total_bytes - cur_start);
3349                 if (cur_start == 0) {
3350                         bit = BLOCK_GROUP_SYSTEM;
3351                         group_type = BTRFS_BLOCK_GROUP_SYSTEM;
3352                         group_size /= 4;
3353                         group_size &= ~(group_align - 1);
3354                         group_size = max_t(u64, group_size, 8 * 1024 * 1024);
3355                         group_size = min_t(u64, group_size, 32 * 1024 * 1024);
3356                 } else {
3357                         group_size &= ~(group_align - 1);
3358                         if (total_data >= total_metadata * 2) {
3359                                 group_type = BTRFS_BLOCK_GROUP_METADATA;
3360                                 group_size = min_t(u64, group_size,
3361                                                    1ULL * 1024 * 1024 * 1024);
3362                                 total_metadata += group_size;
3363                         } else {
3364                                 group_type = BTRFS_BLOCK_GROUP_DATA;
3365                                 group_size = min_t(u64, group_size,
3366                                                    5ULL * 1024 * 1024 * 1024);
3367                                 total_data += group_size;
3368                         }
3369                         if ((total_bytes - cur_start) * 4 < group_size * 5)
3370                                 group_size = total_bytes - cur_start;
3371                 }
3372
3373                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3374                 BUG_ON(!cache);
3375
3376                 cache->key.objectid = cur_start;
3377                 cache->key.offset = group_size;
3378                 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3379
3380                 btrfs_set_block_group_used(&cache->item, 0);
3381                 btrfs_set_block_group_chunk_objectid(&cache->item,
3382                                                      chunk_objectid);
3383                 btrfs_set_block_group_flags(&cache->item, group_type);
3384
3385                 cache->flags = group_type;
3386
3387                 ret = update_space_info(root->fs_info, group_type, group_size,
3388                                         0, &cache->space_info);
3389                 BUG_ON(ret);
3390                 set_avail_alloc_bits(extent_root->fs_info, group_type);
3391
3392                 set_extent_bits(block_group_cache, cur_start,
3393                                 cur_start + group_size - 1,
3394                                 bit | EXTENT_LOCKED, GFP_NOFS);
3395                 set_state_private(block_group_cache, cur_start,
3396                                   (unsigned long)cache);
3397                 cur_start += group_size;
3398         }
3399         /* then insert all the items */
3400         cur_start = 0;
3401         while(cur_start < total_bytes) {
3402                 cache = btrfs_lookup_block_group(root->fs_info, cur_start);
3403                 BUG_ON(!cache);
3404
3405                 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3406                                         sizeof(cache->item));
3407                 BUG_ON(ret);
3408
3409                 finish_current_insert(trans, extent_root);
3410                 ret = del_pending_extents(trans, extent_root);
3411                 BUG_ON(ret);
3412
3413                 cur_start = cache->key.objectid + cache->key.offset;
3414         }
3415         return 0;
3416 }
3417
3418 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3419                              struct btrfs_root *root,
3420                              u64 bytenr, u64 num_bytes, int alloc,
3421                              int mark_free)
3422 {
3423         return update_block_group(trans, root, bytenr, num_bytes,
3424                                   alloc, mark_free);
3425 }
3426
3427 static int btrfs_count_extents_in_block_group(struct btrfs_root *root,
3428                                               struct btrfs_path *path, u64 start,
3429                                               u64 len,
3430                                               u64 *total)
3431 {
3432         struct btrfs_key key;
3433         struct extent_buffer *leaf;
3434         u64 bytes_used = 0;
3435         int ret;
3436         int slot;
3437
3438         key.offset = 0;
3439         key.objectid = start;
3440         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
3441         ret = btrfs_search_slot(NULL, root->fs_info->extent_root,
3442                                 &key, path, 0, 0);
3443         if (ret < 0)
3444                 return ret;
3445         while(1) {
3446                 leaf = path->nodes[0];
3447                 slot = path->slots[0];
3448                 if (slot >= btrfs_header_nritems(leaf)) {
3449                         ret = btrfs_next_leaf(root, path);
3450                         if (ret < 0)
3451                                 return ret;
3452                         if (ret > 0)
3453                                 break;
3454                         leaf = path->nodes[0];
3455                         slot = path->slots[0];
3456                 }
3457                 btrfs_item_key_to_cpu(leaf, &key, slot);
3458                 if (key.objectid > start + len)
3459                         break;
3460                 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3461                         bytes_used += key.offset;
3462                 if (key.type == BTRFS_METADATA_ITEM_KEY)
3463                         bytes_used += root->leafsize;
3464                 path->slots[0]++;
3465         }
3466         *total = bytes_used;
3467         btrfs_release_path(root, path);
3468         return 0;
3469 }
3470
3471 int btrfs_check_block_accounting(struct btrfs_root *root)
3472 {
3473         int ret;
3474         u64 start = 0;
3475         u64 bytes_used = 0;
3476         struct btrfs_path path;
3477         struct btrfs_block_group_cache *cache;
3478         struct btrfs_fs_info *fs_info = root->fs_info;
3479
3480         btrfs_init_path(&path);
3481
3482         while(1) {
3483                 cache = btrfs_lookup_block_group(fs_info, start);
3484                 if (!cache)
3485                         break;
3486
3487                 ret = btrfs_count_extents_in_block_group(root, &path,
3488                                                          cache->key.objectid,
3489                                                          cache->key.offset,
3490                                                          &bytes_used);
3491
3492                 if (ret == 0) {
3493                         u64 on_disk = btrfs_block_group_used(&cache->item);
3494                         if (on_disk != bytes_used) {
3495                                 fprintf(stderr, "bad block group accounting found %llu "
3496                                         "expected %llu block group %llu\n",
3497                                         (unsigned long long)bytes_used,
3498                                         (unsigned long long)on_disk,
3499                                         (unsigned long long)cache->key.objectid);
3500                         }
3501                 }
3502                 start = cache->key.objectid + cache->key.offset;
3503
3504                 cache->space_info->bytes_used = 0;
3505         }
3506         return 0;
3507 }
3508
3509 /*
3510  * Fixup block accounting. The initial block accounting created by
3511  * make_block_groups isn't accuracy in this case.
3512  */
3513 int btrfs_fix_block_accounting(struct btrfs_trans_handle *trans,
3514                                struct btrfs_root *root)
3515 {
3516         int ret;
3517         int slot;
3518         u64 start = 0;
3519         u64 bytes_used = 0;
3520         struct btrfs_path path;
3521         struct btrfs_key key;
3522         struct extent_buffer *leaf;
3523         struct btrfs_block_group_cache *cache;
3524         struct btrfs_fs_info *fs_info = root->fs_info;
3525
3526         root = root->fs_info->extent_root;
3527
3528         while(extent_root_pending_ops(fs_info)) {
3529                 ret = finish_current_insert(trans, root);
3530                 if (ret)
3531                         return ret;
3532                 ret = del_pending_extents(trans, root);
3533                 if (ret)
3534                         return ret;
3535         }
3536
3537         while(1) {
3538                 cache = btrfs_lookup_first_block_group(fs_info, start);
3539                 if (!cache)
3540                         break;
3541                 start = cache->key.objectid + cache->key.offset;
3542                 btrfs_set_block_group_used(&cache->item, 0);
3543                 cache->space_info->bytes_used = 0;
3544                 set_extent_bits(&root->fs_info->block_group_cache,
3545                                 cache->key.objectid,
3546                                 cache->key.objectid + cache->key.offset -1,
3547                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
3548         }
3549
3550         btrfs_init_path(&path);
3551         key.offset = 0;
3552         key.objectid = 0;
3553         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
3554         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
3555                                 &key, &path, 0, 0);
3556         if (ret < 0)
3557                 return ret;
3558         while(1) {
3559                 leaf = path.nodes[0];
3560                 slot = path.slots[0];
3561                 if (slot >= btrfs_header_nritems(leaf)) {
3562                         ret = btrfs_next_leaf(root, &path);
3563                         if (ret < 0)
3564                                 return ret;
3565                         if (ret > 0)
3566                                 break;
3567                         leaf = path.nodes[0];
3568                         slot = path.slots[0];
3569                 }
3570                 btrfs_item_key_to_cpu(leaf, &key, slot);
3571                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
3572                         bytes_used += key.offset;
3573                         ret = btrfs_update_block_group(trans, root,
3574                                   key.objectid, key.offset, 1, 0);
3575                         BUG_ON(ret);
3576                 } else if (key.type == BTRFS_METADATA_ITEM_KEY) {
3577                         bytes_used += root->leafsize;
3578                         ret = btrfs_update_block_group(trans, root,
3579                                   key.objectid, root->leafsize, 1, 0);
3580                         BUG_ON(ret);
3581                 }
3582                 path.slots[0]++;
3583         }
3584         btrfs_set_super_bytes_used(root->fs_info->super_copy, bytes_used);
3585         btrfs_release_path(root, &path);
3586         return 0;
3587 }