extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include "kerncompat.h"
  22 #include "radix-tree.h"
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "print-tree.h"
  26 #include "transaction.h"
  27 #include "crc32c.h"
  28 #include "volumes.h"
  29
  30 #define BLOCK_GROUP_DATA     EXTENT_WRITEBACK
  31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
  32 #define BLOCK_GROUP_SYSTEM   EXTENT_NEW
  33
  34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
  35
  36 #define PENDING_EXTENT_INSERT 0
  37 #define PENDING_EXTENT_DELETE 1
  38 #define PENDING_BACKREF_UPDATE 2
  39
  40 struct pending_extent_op {
  41         int type;
  42         u64 bytenr;
  43         u64 num_bytes;
  44         u64 flags;
  45         struct btrfs_disk_key key;
  46         int level;
  47 };
  48
  49 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  50                                      struct btrfs_root *root,
  51                                      u64 root_objectid, u64 generation,
  52                                      u64 flags, struct btrfs_disk_key *key,
  53                                      int level, struct btrfs_key *ins);
  54 static int __free_extent(struct btrfs_trans_handle *trans,
  55                          struct btrfs_root *root,
  56                          u64 bytenr, u64 num_bytes, u64 parent,
  57                          u64 root_objectid, u64 owner_objectid,
  58                          u64 owner_offset, int refs_to_drop);
  59 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  60                                  btrfs_root *extent_root);
  61 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  62                                btrfs_root *extent_root);
  63
  64 static int remove_sb_from_cache(struct btrfs_root *root,
  65                                 struct btrfs_block_group_cache *cache)
  66 {
  67         u64 bytenr;
  68         u64 *logical;
  69         int stripe_len;
  70         int i, nr, ret;
  71         struct extent_io_tree *free_space_cache;
  72
  73         free_space_cache = &root->fs_info->free_space_cache;
  74         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
  75                 bytenr = btrfs_sb_offset(i);
  76                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
  77                                        cache->key.objectid, bytenr, 0,
  78                                        &logical, &nr, &stripe_len);
  79                 BUG_ON(ret);
  80                 while (nr--) {
  81                         clear_extent_dirty(free_space_cache, logical[nr],
  82                                 logical[nr] + stripe_len - 1, GFP_NOFS);
  83                 }
  84                 kfree(logical);
  85         }
  86         return 0;
  87 }
  88
  89 static int cache_block_group(struct btrfs_root *root,
  90                              struct btrfs_block_group_cache *block_group)
  91 {
  92         struct btrfs_path *path;
  93         int ret;
  94         struct btrfs_key key;
  95         struct extent_buffer *leaf;
  96         struct extent_io_tree *free_space_cache;
  97         int slot;
  98         u64 last;
  99         u64 hole_size;
 100
 101         if (!block_group)
 102                 return 0;
 103
 104         root = root->fs_info->extent_root;
 105         free_space_cache = &root->fs_info->free_space_cache;
 106
 107         if (block_group->cached)
 108                 return 0;
 109
 110         path = btrfs_alloc_path();
 111         if (!path)
 112                 return -ENOMEM;
 113
 114         path->reada = 2;
 115         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 116         key.objectid = last;
 117         key.offset = 0;
 118         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 119         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 120         if (ret < 0)
 121                 goto err;
 122
 123         while(1) {
 124                 leaf = path->nodes[0];
 125                 slot = path->slots[0];
 126                 if (slot >= btrfs_header_nritems(leaf)) {
 127                         ret = btrfs_next_leaf(root, path);
 128                         if (ret < 0)
 129                                 goto err;
 130                         if (ret == 0) {
 131                                 continue;
 132                         } else {
 133                                 break;
 134                         }
 135                 }
 136                 btrfs_item_key_to_cpu(leaf, &key, slot);
 137                 if (key.objectid < block_group->key.objectid) {
 138                         goto next;
 139                 }
 140                 if (key.objectid >= block_group->key.objectid +
 141                     block_group->key.offset) {
 142                         break;
 143                 }
 144
 145                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 146                         if (key.objectid > last) {
 147                                 hole_size = key.objectid - last;
 148                                 set_extent_dirty(free_space_cache, last,
 149                                                  last + hole_size - 1,
 150                                                  GFP_NOFS);
 151                         }
 152                         last = key.objectid + key.offset;
 153                 }
 154 next:
 155                 path->slots[0]++;
 156         }
 157
 158         if (block_group->key.objectid +
 159             block_group->key.offset > last) {
 160                 hole_size = block_group->key.objectid +
 161                         block_group->key.offset - last;
 162                 set_extent_dirty(free_space_cache, last,
 163                                  last + hole_size - 1, GFP_NOFS);
 164         }
 165         remove_sb_from_cache(root, block_group);
 166         block_group->cached = 1;
 167 err:
 168         btrfs_free_path(path);
 169         return 0;
 170 }
 171
 172 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
 173                                                        btrfs_fs_info *info,
 174                                                        u64 bytenr)
 175 {
 176         struct extent_io_tree *block_group_cache;
 177         struct btrfs_block_group_cache *block_group = NULL;
 178         u64 ptr;
 179         u64 start;
 180         u64 end;
 181         int ret;
 182
 183         bytenr = max_t(u64, bytenr,
 184                        BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
 185         block_group_cache = &info->block_group_cache;
 186         ret = find_first_extent_bit(block_group_cache,
 187                                     bytenr, &start, &end,
 188                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 189                                     BLOCK_GROUP_SYSTEM);
 190         if (ret) {
 191                 return NULL;
 192         }
 193         ret = get_state_private(block_group_cache, start, &ptr);
 194         if (ret)
 195                 return NULL;
 196
 197         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 198         return block_group;
 199 }
 200
 201 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
 202                                                          btrfs_fs_info *info,
 203                                                          u64 bytenr)
 204 {
 205         struct extent_io_tree *block_group_cache;
 206         struct btrfs_block_group_cache *block_group = NULL;
 207         u64 ptr;
 208         u64 start;
 209         u64 end;
 210         int ret;
 211
 212         block_group_cache = &info->block_group_cache;
 213         ret = find_first_extent_bit(block_group_cache,
 214                                     bytenr, &start, &end,
 215                                     BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
 216                                     BLOCK_GROUP_SYSTEM);
 217         if (ret) {
 218                 return NULL;
 219         }
 220         ret = get_state_private(block_group_cache, start, &ptr);
 221         if (ret)
 222                 return NULL;
 223
 224         block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 225         if (block_group->key.objectid <= bytenr && bytenr <
 226             block_group->key.objectid + block_group->key.offset)
 227                 return block_group;
 228         return NULL;
 229 }
 230
 231 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 232 {
 233         return (cache->flags & bits) == bits;
 234 }
 235
 236 static int noinline find_search_start(struct btrfs_root *root,
 237                               struct btrfs_block_group_cache **cache_ret,
 238                               u64 *start_ret, int num, int data)
 239 {
 240         int ret;
 241         struct btrfs_block_group_cache *cache = *cache_ret;
 242         u64 last;
 243         u64 start = 0;
 244         u64 end = 0;
 245         u64 search_start = *start_ret;
 246         int wrapped = 0;
 247
 248         if (!cache) {
 249                 goto out;
 250         }
 251 again:
 252         ret = cache_block_group(root, cache);
 253         if (ret)
 254                 goto out;
 255
 256         last = max(search_start, cache->key.objectid);
 257         if (cache->ro || !block_group_bits(cache, data)) {
 258                 goto new_group;
 259         }
 260
 261         while(1) {
 262                 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
 263                                             last, &start, &end, EXTENT_DIRTY);
 264                 if (ret) {
 265                         goto new_group;
 266                 }
 267
 268                 start = max(last, start);
 269                 last = end + 1;
 270                 if (last - start < num) {
 271                         continue;
 272                 }
 273                 if (start + num > cache->key.objectid + cache->key.offset) {
 274                         goto new_group;
 275                 }
 276                 *start_ret = start;
 277                 return 0;
 278         }
 279 out:
 280         cache = btrfs_lookup_block_group(root->fs_info, search_start);
 281         if (!cache) {
 282                 printk("Unable to find block group for %llu\n",
 283                         (unsigned long long)search_start);
 284                 WARN_ON(1);
 285         }
 286         return -ENOSPC;
 287
 288 new_group:
 289         last = cache->key.objectid + cache->key.offset;
 290 wrapped:
 291         cache = btrfs_lookup_first_block_group(root->fs_info, last);
 292         if (!cache) {
 293 no_cache:
 294                 if (!wrapped) {
 295                         wrapped = 1;
 296                         last = search_start;
 297                         goto wrapped;
 298                 }
 299                 goto out;
 300         }
 301         cache = btrfs_find_block_group(root, cache, last, data, 0);
 302         cache = btrfs_find_block_group(root, cache, last, data, 0);
 303         if (!cache)
 304                 goto no_cache;
 305
 306         *cache_ret = cache;
 307         goto again;
 308 }
 309
 310 static u64 div_factor(u64 num, int factor)
 311 {
 312         if (factor == 10)
 313                 return num;
 314         num *= factor;
 315         num /= 10;
 316         return num;
 317 }
 318
 319 static int block_group_state_bits(u64 flags)
 320 {
 321         int bits = 0;
 322         if (flags & BTRFS_BLOCK_GROUP_DATA)
 323                 bits |= BLOCK_GROUP_DATA;
 324         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 325                 bits |= BLOCK_GROUP_METADATA;
 326         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 327                 bits |= BLOCK_GROUP_SYSTEM;
 328         return bits;
 329 }
 330
 331 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 332                                                  struct btrfs_block_group_cache
 333                                                  *hint, u64 search_start,
 334                                                  int data, int owner)
 335 {
 336         struct btrfs_block_group_cache *cache;
 337         struct extent_io_tree *block_group_cache;
 338         struct btrfs_block_group_cache *found_group = NULL;
 339         struct btrfs_fs_info *info = root->fs_info;
 340         u64 used;
 341         u64 last = 0;
 342         u64 hint_last;
 343         u64 start;
 344         u64 end;
 345         u64 free_check;
 346         u64 ptr;
 347         int bit;
 348         int ret;
 349         int full_search = 0;
 350         int factor = 10;
 351
 352         block_group_cache = &info->block_group_cache;
 353
 354         if (!owner)
 355                 factor = 10;
 356
 357         bit = block_group_state_bits(data);
 358
 359         if (search_start) {
 360                 struct btrfs_block_group_cache *shint;
 361                 shint = btrfs_lookup_block_group(info, search_start);
 362                 if (shint && !shint->ro && block_group_bits(shint, data)) {
 363                         used = btrfs_block_group_used(&shint->item);
 364                         if (used + shint->pinned <
 365                             div_factor(shint->key.offset, factor)) {
 366                                 return shint;
 367                         }
 368                 }
 369         }
 370         if (hint && !hint->ro && block_group_bits(hint, data)) {
 371                 used = btrfs_block_group_used(&hint->item);
 372                 if (used + hint->pinned <
 373                     div_factor(hint->key.offset, factor)) {
 374                         return hint;
 375                 }
 376                 last = hint->key.objectid + hint->key.offset;
 377                 hint_last = last;
 378         } else {
 379                 if (hint)
 380                         hint_last = max(hint->key.objectid, search_start);
 381                 else
 382                         hint_last = search_start;
 383
 384                 last = hint_last;
 385         }
 386 again:
 387         while(1) {
 388                 ret = find_first_extent_bit(block_group_cache, last,
 389                                             &start, &end, bit);
 390                 if (ret)
 391                         break;
 392
 393                 ret = get_state_private(block_group_cache, start, &ptr);
 394                 if (ret)
 395                         break;
 396
 397                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
 398                 last = cache->key.objectid + cache->key.offset;
 399                 used = btrfs_block_group_used(&cache->item);
 400
 401                 if (!cache->ro && block_group_bits(cache, data)) {
 402                         if (full_search)
 403                                 free_check = cache->key.offset;
 404                         else
 405                                 free_check = div_factor(cache->key.offset,
 406                                                         factor);
 407
 408                         if (used + cache->pinned < free_check) {
 409                                 found_group = cache;
 410                                 goto found;
 411                         }
 412                 }
 413                 cond_resched();
 414         }
 415         if (!full_search) {
 416                 last = search_start;
 417                 full_search = 1;
 418                 goto again;
 419         }
 420 found:
 421         return found_group;
 422 }
 423
 424 /*
 425  * Back reference rules.  Back refs have three main goals:
 426  *
 427  * 1) differentiate between all holders of references to an extent so that
 428  *    when a reference is dropped we can make sure it was a valid reference
 429  *    before freeing the extent.
 430  *
 431  * 2) Provide enough information to quickly find the holders of an extent
 432  *    if we notice a given block is corrupted or bad.
 433  *
 434  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 435  *    maintenance.  This is actually the same as #2, but with a slightly
 436  *    different use case.
 437  *
 438  * There are two kinds of back refs. The implicit back refs is optimized
 439  * for pointers in non-shared tree blocks. For a given pointer in a block,
 440  * back refs of this kind provide information about the block's owner tree
 441  * and the pointer's key. These information allow us to find the block by
 442  * b-tree searching. The full back refs is for pointers in tree blocks not
 443  * referenced by their owner trees. The location of tree block is recorded
 444  * in the back refs. Actually the full back refs is generic, and can be
 445  * used in all cases the implicit back refs is used. The major shortcoming
 446  * of the full back refs is its overhead. Every time a tree block gets
 447  * COWed, we have to update back refs entry for all pointers in it.
 448  *
 449  * For a newly allocated tree block, we use implicit back refs for
 450  * pointers in it. This means most tree related operations only involve
 451  * implicit back refs. For a tree block created in old transaction, the
 452  * only way to drop a reference to it is COW it. So we can detect the
 453  * event that tree block loses its owner tree's reference and do the
 454  * back refs conversion.
 455  *
 456  * When a tree block is COW'd through a tree, there are four cases:
 457  *
 458  * The reference count of the block is one and the tree is the block's
 459  * owner tree. Nothing to do in this case.
 460  *
 461  * The reference count of the block is one and the tree is not the
 462  * block's owner tree. In this case, full back refs is used for pointers
 463  * in the block. Remove these full back refs, add implicit back refs for
 464  * every pointers in the new block.
 465  *
 466  * The reference count of the block is greater than one and the tree is
 467  * the block's owner tree. In this case, implicit back refs is used for
 468  * pointers in the block. Add full back refs for every pointers in the
 469  * block, increase lower level extents' reference counts. The original
 470  * implicit back refs are entailed to the new block.
 471  *
 472  * The reference count of the block is greater than one and the tree is
 473  * not the block's owner tree. Add implicit back refs for every pointer in
 474  * the new block, increase lower level extents' reference count.
 475  *
 476  * Back Reference Key composing:
 477  *
 478  * The key objectid corresponds to the first byte in the extent,
 479  * The key type is used to differentiate between types of back refs.
 480  * There are different meanings of the key offset for different types
 481  * of back refs.
 482  *
 483  * File extents can be referenced by:
 484  *
 485  * - multiple snapshots, subvolumes, or different generations in one subvol
 486  * - different files inside a single subvolume
 487  * - different offsets inside a file (bookend extents in file.c)
 488  *
 489  * The extent ref structure for the implicit back refs has fields for:
 490  *
 491  * - Objectid of the subvolume root
 492  * - objectid of the file holding the reference
 493  * - original offset in the file
 494  * - how many bookend extents
 495  *
 496  * The key offset for the implicit back refs is hash of the first
 497  * three fields.
 498  *
 499  * The extent ref structure for the full back refs has field for:
 500  *
 501  * - number of pointers in the tree leaf
 502  *
 503  * The key offset for the implicit back refs is the first byte of
 504  * the tree leaf
 505  *
 506  * When a file extent is allocated, The implicit back refs is used.
 507  * the fields are filled in:
 508  *
 509  *     (root_key.objectid, inode objectid, offset in file, 1)
 510  *
 511  * When a file extent is removed file truncation, we find the
 512  * corresponding implicit back refs and check the following fields:
 513  *
 514  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 515  *
 516  * Btree extents can be referenced by:
 517  *
 518  * - Different subvolumes
 519  *
 520  * Both the implicit back refs and the full back refs for tree blocks
 521  * only consist of key. The key offset for the implicit back refs is
 522  * objectid of block's owner tree. The key offset for the full back refs
 523  * is the first byte of parent block.
 524  *
 525  * When implicit back refs is used, information about the lowest key and
 526  * level of the tree block are required. These information are stored in
 527  * tree block info structure.
 528  */
 529
 530 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 531 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 532                                   struct btrfs_root *root,
 533                                   struct btrfs_path *path,
 534                                   u64 owner, u32 extra_size)
 535 {
 536         struct btrfs_extent_item *item;
 537         struct btrfs_extent_item_v0 *ei0;
 538         struct btrfs_extent_ref_v0 *ref0;
 539         struct btrfs_tree_block_info *bi;
 540         struct extent_buffer *leaf;
 541         struct btrfs_key key;
 542         struct btrfs_key found_key;
 543         u32 new_size = sizeof(*item);
 544         u64 refs;
 545         int ret;
 546
 547         leaf = path->nodes[0];
 548         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 549
 550         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 551         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 552                              struct btrfs_extent_item_v0);
 553         refs = btrfs_extent_refs_v0(leaf, ei0);
 554
 555         if (owner == (u64)-1) {
 556                 while (1) {
 557                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 558                                 ret = btrfs_next_leaf(root, path);
 559                                 if (ret < 0)
 560                                         return ret;
 561                                 BUG_ON(ret > 0);
 562                                 leaf = path->nodes[0];
 563                         }
 564                         btrfs_item_key_to_cpu(leaf, &found_key,
 565                                               path->slots[0]);
 566                         BUG_ON(key.objectid != found_key.objectid);
 567                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 568                                 path->slots[0]++;
 569                                 continue;
 570                         }
 571                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 572                                               struct btrfs_extent_ref_v0);
 573                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 574                         break;
 575                 }
 576         }
 577         btrfs_release_path(root, path);
 578
 579         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 580                 new_size += sizeof(*bi);
 581
 582         new_size -= sizeof(*ei0);
 583         ret = btrfs_search_slot(trans, root, &key, path, new_size, 1);
 584         if (ret < 0)
 585                 return ret;
 586         BUG_ON(ret);
 587
 588         ret = btrfs_extend_item(trans, root, path, new_size);
 589         BUG_ON(ret);
 590
 591         leaf = path->nodes[0];
 592         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 593         btrfs_set_extent_refs(leaf, item, refs);
 594         /* FIXME: get real generation */
 595         btrfs_set_extent_generation(leaf, item, 0);
 596         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 597                 btrfs_set_extent_flags(leaf, item,
 598                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 599                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 600                 bi = (struct btrfs_tree_block_info *)(item + 1);
 601                 /* FIXME: get first key of the block */
 602                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 603                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 604         } else {
 605                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 606         }
 607         btrfs_mark_buffer_dirty(leaf);
 608         return 0;
 609 }
 610 #endif
 611
 612 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 613 {
 614         u32 high_crc = ~(u32)0;
 615         u32 low_crc = ~(u32)0;
 616         __le64 lenum;
 617
 618         lenum = cpu_to_le64(root_objectid);
 619         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 620         lenum = cpu_to_le64(owner);
 621         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 622         lenum = cpu_to_le64(offset);
 623         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 624
 625         return ((u64)high_crc << 31) ^ (u64)low_crc;
 626 }
 627
 628 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 629                                      struct btrfs_extent_data_ref *ref)
 630 {
 631         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 632                                     btrfs_extent_data_ref_objectid(leaf, ref),
 633                                     btrfs_extent_data_ref_offset(leaf, ref));
 634 }
 635
 636 static int match_extent_data_ref(struct extent_buffer *leaf,
 637                                  struct btrfs_extent_data_ref *ref,
 638                                  u64 root_objectid, u64 owner, u64 offset)
 639 {
 640         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 641             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 642             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 643                 return 0;
 644         return 1;
 645 }
 646
 647 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 648                                            struct btrfs_root *root,
 649                                            struct btrfs_path *path,
 650                                            u64 bytenr, u64 parent,
 651                                            u64 root_objectid,
 652                                            u64 owner, u64 offset)
 653 {
 654         struct btrfs_key key;
 655         struct btrfs_extent_data_ref *ref;
 656         struct extent_buffer *leaf;
 657         u32 nritems;
 658         int ret;
 659         int recow;
 660         int err = -ENOENT;
 661
 662         key.objectid = bytenr;
 663         if (parent) {
 664                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 665                 key.offset = parent;
 666         } else {
 667                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 668                 key.offset = hash_extent_data_ref(root_objectid,
 669                                                   owner, offset);
 670         }
 671 again:
 672         recow = 0;
 673         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 674         if (ret < 0) {
 675                 err = ret;
 676                 goto fail;
 677         }
 678
 679         if (parent) {
 680                 if (!ret)
 681                         return 0;
 682 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 683                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 684                 btrfs_release_path(root, path);
 685                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 686                 if (ret < 0) {
 687                         err = ret;
 688                         goto fail;
 689                 }
 690                 if (!ret)
 691                         return 0;
 692 #endif
 693                 goto fail;
 694         }
 695
 696         leaf = path->nodes[0];
 697         nritems = btrfs_header_nritems(leaf);
 698         while (1) {
 699                 if (path->slots[0] >= nritems) {
 700                         ret = btrfs_next_leaf(root, path);
 701                         if (ret < 0)
 702                                 err = ret;
 703                         if (ret)
 704                                 goto fail;
 705
 706                         leaf = path->nodes[0];
 707                         nritems = btrfs_header_nritems(leaf);
 708                         recow = 1;
 709                 }
 710
 711                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 712                 if (key.objectid != bytenr ||
 713                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 714                         goto fail;
 715
 716                 ref = btrfs_item_ptr(leaf, path->slots[0],
 717                                      struct btrfs_extent_data_ref);
 718
 719                 if (match_extent_data_ref(leaf, ref, root_objectid,
 720                                           owner, offset)) {
 721                         if (recow) {
 722                                 btrfs_release_path(root, path);
 723                                 goto again;
 724                         }
 725                         err = 0;
 726                         break;
 727                 }
 728                 path->slots[0]++;
 729         }
 730 fail:
 731         return err;
 732 }
 733
 734 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 735                                            struct btrfs_root *root,
 736                                            struct btrfs_path *path,
 737                                            u64 bytenr, u64 parent,
 738                                            u64 root_objectid, u64 owner,
 739                                            u64 offset, int refs_to_add)
 740 {
 741         struct btrfs_key key;
 742         struct extent_buffer *leaf;
 743         u32 size;
 744         u32 num_refs;
 745         int ret;
 746
 747         key.objectid = bytenr;
 748         if (parent) {
 749                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 750                 key.offset = parent;
 751                 size = sizeof(struct btrfs_shared_data_ref);
 752         } else {
 753                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 754                 key.offset = hash_extent_data_ref(root_objectid,
 755                                                   owner, offset);
 756                 size = sizeof(struct btrfs_extent_data_ref);
 757         }
 758
 759         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 760         if (ret && ret != -EEXIST)
 761                 goto fail;
 762
 763         leaf = path->nodes[0];
 764         if (parent) {
 765                 struct btrfs_shared_data_ref *ref;
 766                 ref = btrfs_item_ptr(leaf, path->slots[0],
 767                                      struct btrfs_shared_data_ref);
 768                 if (ret == 0) {
 769                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 770                 } else {
 771                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 772                         num_refs += refs_to_add;
 773                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 774                 }
 775         } else {
 776                 struct btrfs_extent_data_ref *ref;
 777                 while (ret == -EEXIST) {
 778                         ref = btrfs_item_ptr(leaf, path->slots[0],
 779                                              struct btrfs_extent_data_ref);
 780                         if (match_extent_data_ref(leaf, ref, root_objectid,
 781                                                   owner, offset))
 782                                 break;
 783                         btrfs_release_path(root, path);
 784
 785                         key.offset++;
 786                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 787                                                       size);
 788                         if (ret && ret != -EEXIST)
 789                                 goto fail;
 790
 791                         leaf = path->nodes[0];
 792                 }
 793                 ref = btrfs_item_ptr(leaf, path->slots[0],
 794                                      struct btrfs_extent_data_ref);
 795                 if (ret == 0) {
 796                         btrfs_set_extent_data_ref_root(leaf, ref,
 797                                                        root_objectid);
 798                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 799                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 800                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 801                 } else {
 802                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 803                         num_refs += refs_to_add;
 804                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 805                 }
 806         }
 807         btrfs_mark_buffer_dirty(leaf);
 808         ret = 0;
 809 fail:
 810         btrfs_release_path(root, path);
 811         return ret;
 812 }
 813
 814 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 815                                            struct btrfs_root *root,
 816                                            struct btrfs_path *path,
 817                                            int refs_to_drop)
 818 {
 819         struct btrfs_key key;
 820         struct btrfs_extent_data_ref *ref1 = NULL;
 821         struct btrfs_shared_data_ref *ref2 = NULL;
 822         struct extent_buffer *leaf;
 823         u32 num_refs = 0;
 824         int ret = 0;
 825
 826         leaf = path->nodes[0];
 827         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 828
 829         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 830                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 831                                       struct btrfs_extent_data_ref);
 832                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 833         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 834                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 835                                       struct btrfs_shared_data_ref);
 836                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 837 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 838         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 839                 struct btrfs_extent_ref_v0 *ref0;
 840                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 841                                       struct btrfs_extent_ref_v0);
 842                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 843 #endif
 844         } else {
 845                 BUG();
 846         }
 847
 848         BUG_ON(num_refs < refs_to_drop);
 849         num_refs -= refs_to_drop;
 850
 851         if (num_refs == 0) {
 852                 ret = btrfs_del_item(trans, root, path);
 853         } else {
 854                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 855                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 856                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 857                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 858 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 859                 else {
 860                         struct btrfs_extent_ref_v0 *ref0;
 861                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 862                                         struct btrfs_extent_ref_v0);
 863                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
 864                 }
 865 #endif
 866                 btrfs_mark_buffer_dirty(leaf);
 867         }
 868         return ret;
 869 }
 870
 871 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
 872                                           struct btrfs_path *path,
 873                                           struct btrfs_extent_inline_ref *iref)
 874 {
 875         struct btrfs_key key;
 876         struct extent_buffer *leaf;
 877         struct btrfs_extent_data_ref *ref1;
 878         struct btrfs_shared_data_ref *ref2;
 879         u32 num_refs = 0;
 880
 881         leaf = path->nodes[0];
 882         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 883         if (iref) {
 884                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
 885                     BTRFS_EXTENT_DATA_REF_KEY) {
 886                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 887                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 888                 } else {
 889                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 890                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 891                 }
 892         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 893                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 894                                       struct btrfs_extent_data_ref);
 895                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 896         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 897                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 898                                       struct btrfs_shared_data_ref);
 899                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 900 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 901         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
 902                 struct btrfs_extent_ref_v0 *ref0;
 903                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
 904                                       struct btrfs_extent_ref_v0);
 905                 num_refs = btrfs_ref_count_v0(leaf, ref0);
 906 #endif
 907         } else {
 908                 BUG();
 909         }
 910         return num_refs;
 911 }
 912
 913 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 914                                           struct btrfs_root *root,
 915                                           struct btrfs_path *path,
 916                                           u64 bytenr, u64 parent,
 917                                           u64 root_objectid)
 918 {
 919         struct btrfs_key key;
 920         int ret;
 921
 922         key.objectid = bytenr;
 923         if (parent) {
 924                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 925                 key.offset = parent;
 926         } else {
 927                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 928                 key.offset = root_objectid;
 929         }
 930
 931         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 932         if (ret > 0)
 933                 ret = -ENOENT;
 934 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 935         if (ret == -ENOENT && parent) {
 936                 btrfs_release_path(root, path);
 937                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 938                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 939                 if (ret > 0)
 940                         ret = -ENOENT;
 941         }
 942 #endif
 943         return ret;
 944 }
 945
 946 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 947                                           struct btrfs_root *root,
 948                                           struct btrfs_path *path,
 949                                           u64 bytenr, u64 parent,
 950                                           u64 root_objectid)
 951 {
 952         struct btrfs_key key;
 953         int ret;
 954
 955         key.objectid = bytenr;
 956         if (parent) {
 957                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 958                 key.offset = parent;
 959         } else {
 960                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 961                 key.offset = root_objectid;
 962         }
 963
 964         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
 965
 966         btrfs_release_path(root, path);
 967         return ret;
 968 }
 969
 970 static inline int extent_ref_type(u64 parent, u64 owner)
 971 {
 972         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 973                 if (parent > 0)
 974                         return BTRFS_SHARED_BLOCK_REF_KEY;
 975                 else
 976                         return BTRFS_TREE_BLOCK_REF_KEY;
 977         } else {
 978                 if (parent > 0)
 979                         return BTRFS_SHARED_DATA_REF_KEY;
 980                 else
 981                         return BTRFS_EXTENT_DATA_REF_KEY;
 982         }
 983 }
 984
 985 static int find_next_key(struct btrfs_path *path, struct btrfs_key *key)
 986
 987 {
 988         int level;
 989         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
 990                 if (!path->nodes[level])
 991                         break;
 992                 if (path->slots[level] + 1 >=
 993                     btrfs_header_nritems(path->nodes[level]))
 994                         continue;
 995                 if (level == 0)
 996                         btrfs_item_key_to_cpu(path->nodes[level], key,
 997                                               path->slots[level] + 1);
 998                 else
 999                         btrfs_node_key_to_cpu(path->nodes[level], key,
1000                                               path->slots[level] + 1);
1001                 return 0;
1002         }
1003         return 1;
1004 }
1005
1006 static int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1007                                  struct btrfs_root *root,
1008                                  struct btrfs_path *path,
1009                                  struct btrfs_extent_inline_ref **ref_ret,
1010                                  u64 bytenr, u64 num_bytes,
1011                                  u64 parent, u64 root_objectid,
1012                                  u64 owner, u64 offset, int insert)
1013 {
1014         struct btrfs_key key;
1015         struct extent_buffer *leaf;
1016         struct btrfs_extent_item *ei;
1017         struct btrfs_extent_inline_ref *iref;
1018         u64 flags;
1019         u32 item_size;
1020         unsigned long ptr;
1021         unsigned long end;
1022         int extra_size;
1023         int type;
1024         int want;
1025         int ret;
1026         int err = 0;
1027
1028         key.objectid = bytenr;
1029         key.type = BTRFS_EXTENT_ITEM_KEY;
1030         key.offset = num_bytes;
1031
1032         want = extent_ref_type(parent, owner);
1033         if (insert)
1034                 extra_size = btrfs_extent_inline_ref_size(want);
1035         else
1036                 extra_size = -1;
1037         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1038         if (ret < 0) {
1039                 err = ret;
1040                 goto out;
1041         }
1042         BUG_ON(ret);
1043
1044         leaf = path->nodes[0];
1045         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1046 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1047         if (item_size < sizeof(*ei)) {
1048                 if (!insert) {
1049                         err = -ENOENT;
1050                         goto out;
1051                 }
1052                 ret = convert_extent_item_v0(trans, root, path, owner,
1053                                              extra_size);
1054                 if (ret < 0) {
1055                         err = ret;
1056                         goto out;
1057                 }
1058                 leaf = path->nodes[0];
1059                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1060         }
1061 #endif
1062         BUG_ON(item_size < sizeof(*ei));
1063
1064         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1065         flags = btrfs_extent_flags(leaf, ei);
1066
1067         ptr = (unsigned long)(ei + 1);
1068         end = (unsigned long)ei + item_size;
1069
1070         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1071                 ptr += sizeof(struct btrfs_tree_block_info);
1072                 BUG_ON(ptr > end);
1073         } else {
1074                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1075         }
1076
1077         err = -ENOENT;
1078         while (1) {
1079                 if (ptr >= end) {
1080                         WARN_ON(ptr > end);
1081                         break;
1082                 }
1083                 iref = (struct btrfs_extent_inline_ref *)ptr;
1084                 type = btrfs_extent_inline_ref_type(leaf, iref);
1085                 if (want < type)
1086                         break;
1087                 if (want > type) {
1088                         ptr += btrfs_extent_inline_ref_size(type);
1089                         continue;
1090                 }
1091
1092                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1093                         struct btrfs_extent_data_ref *dref;
1094                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1095                         if (match_extent_data_ref(leaf, dref, root_objectid,
1096                                                   owner, offset)) {
1097                                 err = 0;
1098                                 break;
1099                         }
1100                         if (hash_extent_data_ref_item(leaf, dref) <
1101                             hash_extent_data_ref(root_objectid, owner, offset))
1102                                 break;
1103                 } else {
1104                         u64 ref_offset;
1105                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1106                         if (parent > 0) {
1107                                 if (parent == ref_offset) {
1108                                         err = 0;
1109                                         break;
1110                                 }
1111                                 if (ref_offset < parent)
1112                                         break;
1113                         } else {
1114                                 if (root_objectid == ref_offset) {
1115                                         err = 0;
1116                                         break;
1117                                 }
1118                                 if (ref_offset < root_objectid)
1119                                         break;
1120                         }
1121                 }
1122                 ptr += btrfs_extent_inline_ref_size(type);
1123         }
1124         if (err == -ENOENT && insert) {
1125                 if (item_size + extra_size >=
1126                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1127                         err = -EAGAIN;
1128                         goto out;
1129                 }
1130                 /*
1131                  * To add new inline back ref, we have to make sure
1132                  * there is no corresponding back ref item.
1133                  * For simplicity, we just do not add new inline back
1134                  * ref if there is any back ref item.
1135                  */
1136                 if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&
1137                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1138                         err = -EAGAIN;
1139                         goto out;
1140                 }
1141         }
1142         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1143 out:
1144         return err;
1145 }
1146
1147 static int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1148                                 struct btrfs_root *root,
1149                                 struct btrfs_path *path,
1150                                 struct btrfs_extent_inline_ref *iref,
1151                                 u64 parent, u64 root_objectid,
1152                                 u64 owner, u64 offset, int refs_to_add)
1153 {
1154         struct extent_buffer *leaf;
1155         struct btrfs_extent_item *ei;
1156         unsigned long ptr;
1157         unsigned long end;
1158         unsigned long item_offset;
1159         u64 refs;
1160         int size;
1161         int type;
1162         int ret;
1163
1164         leaf = path->nodes[0];
1165         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1166         item_offset = (unsigned long)iref - (unsigned long)ei;
1167
1168         type = extent_ref_type(parent, owner);
1169         size = btrfs_extent_inline_ref_size(type);
1170
1171         ret = btrfs_extend_item(trans, root, path, size);
1172         BUG_ON(ret);
1173
1174         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1175         refs = btrfs_extent_refs(leaf, ei);
1176         refs += refs_to_add;
1177         btrfs_set_extent_refs(leaf, ei, refs);
1178
1179         ptr = (unsigned long)ei + item_offset;
1180         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1181         if (ptr < end - size)
1182                 memmove_extent_buffer(leaf, ptr + size, ptr,
1183                                       end - size - ptr);
1184
1185         iref = (struct btrfs_extent_inline_ref *)ptr;
1186         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1187         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1188                 struct btrfs_extent_data_ref *dref;
1189                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1190                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1191                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1192                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1193                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1194         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1195                 struct btrfs_shared_data_ref *sref;
1196                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1197                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1198                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1199         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1200                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1201         } else {
1202                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1203         }
1204         btrfs_mark_buffer_dirty(leaf);
1205         return 0;
1206 }
1207
1208 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1209                                  struct btrfs_root *root,
1210                                  struct btrfs_path *path,
1211                                  struct btrfs_extent_inline_ref **ref_ret,
1212                                  u64 bytenr, u64 num_bytes, u64 parent,
1213                                  u64 root_objectid, u64 owner, u64 offset)
1214 {
1215         int ret;
1216
1217         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1218                                            bytenr, num_bytes, parent,
1219                                            root_objectid, owner, offset, 0);
1220         if (ret != -ENOENT)
1221                 return ret;
1222
1223         btrfs_release_path(root, path);
1224         *ref_ret = NULL;
1225
1226         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1227                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1228                                             root_objectid);
1229         } else {
1230                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1231                                              root_objectid, owner, offset);
1232         }
1233         return ret;
1234 }
1235
1236 static int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1237                                  struct btrfs_root *root,
1238                                  struct btrfs_path *path,
1239                                  struct btrfs_extent_inline_ref *iref,
1240                                  int refs_to_mod)
1241 {
1242         struct extent_buffer *leaf;
1243         struct btrfs_extent_item *ei;
1244         struct btrfs_extent_data_ref *dref = NULL;
1245         struct btrfs_shared_data_ref *sref = NULL;
1246         unsigned long ptr;
1247         unsigned long end;
1248         u32 item_size;
1249         int size;
1250         int type;
1251         int ret;
1252         u64 refs;
1253
1254         leaf = path->nodes[0];
1255         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1256         refs = btrfs_extent_refs(leaf, ei);
1257         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1258         refs += refs_to_mod;
1259         btrfs_set_extent_refs(leaf, ei, refs);
1260
1261         type = btrfs_extent_inline_ref_type(leaf, iref);
1262
1263         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1264                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1265                 refs = btrfs_extent_data_ref_count(leaf, dref);
1266         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1267                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1268                 refs = btrfs_shared_data_ref_count(leaf, sref);
1269         } else {
1270                 refs = 1;
1271                 BUG_ON(refs_to_mod != -1);
1272         }
1273
1274         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1275         refs += refs_to_mod;
1276
1277         if (refs > 0) {
1278                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1279                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1280                 else
1281                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1282         } else {
1283                 size =  btrfs_extent_inline_ref_size(type);
1284                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1285                 ptr = (unsigned long)iref;
1286                 end = (unsigned long)ei + item_size;
1287                 if (ptr + size < end)
1288                         memmove_extent_buffer(leaf, ptr, ptr + size,
1289                                               end - ptr - size);
1290                 item_size -= size;
1291                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1292                 BUG_ON(ret);
1293         }
1294         btrfs_mark_buffer_dirty(leaf);
1295         return 0;
1296 }
1297
1298 static int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1299                                  struct btrfs_root *root,
1300                                  struct btrfs_path *path,
1301                                  u64 bytenr, u64 num_bytes, u64 parent,
1302                                  u64 root_objectid, u64 owner,
1303                                  u64 offset, int refs_to_add)
1304 {
1305         struct btrfs_extent_inline_ref *iref;
1306         int ret;
1307
1308         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1309                                            bytenr, num_bytes, parent,
1310                                            root_objectid, owner, offset, 1);
1311         if (ret == 0) {
1312                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1313                 ret = update_inline_extent_backref(trans, root, path, iref,
1314                                                    refs_to_add);
1315         } else if (ret == -ENOENT) {
1316                 ret = setup_inline_extent_backref(trans, root, path, iref,
1317                                                   parent, root_objectid,
1318                                                   owner, offset, refs_to_add);
1319         }
1320         return ret;
1321 }
1322
1323 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1324                                  struct btrfs_root *root,
1325                                  struct btrfs_path *path,
1326                                  u64 bytenr, u64 parent, u64 root_objectid,
1327                                  u64 owner, u64 offset, int refs_to_add)
1328 {
1329         int ret;
1330
1331         if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
1332                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1333                                              parent, root_objectid,
1334                                              owner, offset, refs_to_add);
1335         } else {
1336                 BUG_ON(refs_to_add != 1);
1337                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1338                                             parent, root_objectid);
1339         }
1340         return ret;
1341 }
1342
1343 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1344                                  struct btrfs_root *root,
1345                                  struct btrfs_path *path,
1346                                  struct btrfs_extent_inline_ref *iref,
1347                                  int refs_to_drop, int is_data)
1348 {
1349         int ret;
1350
1351         BUG_ON(!is_data && refs_to_drop != 1);
1352         if (iref) {
1353                 ret = update_inline_extent_backref(trans, root, path, iref,
1354                                                    -refs_to_drop);
1355         } else if (is_data) {
1356                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1357         } else {
1358                 ret = btrfs_del_item(trans, root, path);
1359         }
1360         return ret;
1361 }
1362
1363 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1364                          struct btrfs_root *root,
1365                          u64 bytenr, u64 num_bytes, u64 parent,
1366                          u64 root_objectid, u64 owner, u64 offset)
1367 {
1368         struct btrfs_path *path;
1369         struct extent_buffer *leaf;
1370         struct btrfs_extent_item *item;
1371         u64 refs;
1372         int ret;
1373         int err = 0;
1374
1375         path = btrfs_alloc_path();
1376         if (!path)
1377                 return -ENOMEM;
1378
1379         path->reada = 1;
1380         path->leave_spinning = 1;
1381
1382         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1383                                            path, bytenr, num_bytes, parent,
1384                                            root_objectid, owner, offset, 1);
1385         if (ret == 0)
1386                 goto out;
1387
1388         if (ret != -EAGAIN) {
1389                 err = ret;
1390                 goto out;
1391         }
1392
1393         leaf = path->nodes[0];
1394         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1395         refs = btrfs_extent_refs(leaf, item);
1396         btrfs_set_extent_refs(leaf, item, refs + 1);
1397
1398         btrfs_mark_buffer_dirty(leaf);
1399         btrfs_release_path(root->fs_info->extent_root, path);
1400
1401         path->reada = 1;
1402         path->leave_spinning = 1;
1403
1404         /* now insert the actual backref */
1405         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1406                                     path, bytenr, parent, root_objectid,
1407                                     owner, offset, 1);
1408         if (ret)
1409                 err = ret;
1410 out:
1411         btrfs_free_path(path);
1412         finish_current_insert(trans, root->fs_info->extent_root);
1413         del_pending_extents(trans, root->fs_info->extent_root);
1414         BUG_ON(err);
1415         return err;
1416 }
1417
1418 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
1419                          struct btrfs_root *root)
1420 {
1421         finish_current_insert(trans, root->fs_info->extent_root);
1422         del_pending_extents(trans, root->fs_info->extent_root);
1423         return 0;
1424 }
1425
1426 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
1427                              struct btrfs_root *root, u64 bytenr,
1428                              u64 num_bytes, u64 *refs, u64 *flags)
1429 {
1430         struct btrfs_path *path;
1431         int ret;
1432         struct btrfs_key key;
1433         struct extent_buffer *l;
1434         struct btrfs_extent_item *item;
1435         u32 item_size;
1436         u64 num_refs;
1437         u64 extent_flags;
1438
1439         WARN_ON(num_bytes < root->sectorsize);
1440         path = btrfs_alloc_path();
1441         path->reada = 1;
1442         key.objectid = bytenr;
1443         key.offset = num_bytes;
1444         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1445         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1446                                 0, 0);
1447         if (ret < 0)
1448                 goto out;
1449         if (ret != 0) {
1450                 btrfs_print_leaf(root, path->nodes[0]);
1451                 printk("failed to find block number %Lu\n", bytenr);
1452                 BUG();
1453         }
1454
1455         l = path->nodes[0];
1456         item_size = btrfs_item_size_nr(l, path->slots[0]);
1457         if (item_size >= sizeof(*item)) {
1458                 item = btrfs_item_ptr(l, path->slots[0],
1459                                       struct btrfs_extent_item);
1460                 num_refs = btrfs_extent_refs(l, item);
1461                 extent_flags = btrfs_extent_flags(l, item);
1462         } else {
1463 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1464                         struct btrfs_extent_item_v0 *ei0;
1465                         BUG_ON(item_size != sizeof(*ei0));
1466                         ei0 = btrfs_item_ptr(l, path->slots[0],
1467                                              struct btrfs_extent_item_v0);
1468                         num_refs = btrfs_extent_refs_v0(l, ei0);
1469                         /* FIXME: this isn't correct for data */
1470                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
1471 #else
1472                         BUG();
1473 #endif
1474                 }
1475                 BUG_ON(num_refs == 0);
1476         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1477         if (refs)
1478                 *refs = num_refs;
1479         if (flags)
1480                 *flags = extent_flags;
1481 out:
1482         btrfs_free_path(path);
1483         return 0;
1484 }
1485
1486 int btrfs_set_block_flags(struct btrfs_trans_handle *trans,
1487                           struct btrfs_root *root,
1488                           u64 bytenr, u64 num_bytes, u64 flags)
1489 {
1490         struct btrfs_path *path;
1491         int ret;
1492         struct btrfs_key key;
1493         struct extent_buffer *l;
1494         struct btrfs_extent_item *item;
1495         u32 item_size;
1496
1497         WARN_ON(num_bytes < root->sectorsize);
1498         path = btrfs_alloc_path();
1499         path->reada = 1;
1500         key.objectid = bytenr;
1501         key.offset = num_bytes;
1502         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1503         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1504                                 0, 0);
1505         if (ret < 0)
1506                 goto out;
1507         if (ret != 0) {
1508                 btrfs_print_leaf(root, path->nodes[0]);
1509                 printk("failed to find block number %Lu\n",
1510                         (unsigned long long)bytenr);
1511                 BUG();
1512         }
1513         l = path->nodes[0];
1514         item_size = btrfs_item_size_nr(l, path->slots[0]);
1515 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1516         if (item_size < sizeof(*item)) {
1517                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1518                                              path, (u64)-1, 0);
1519                 if (ret < 0)
1520                         goto out;
1521
1522                 l = path->nodes[0];
1523                 item_size = btrfs_item_size_nr(l, path->slots[0]);
1524         }
1525 #endif
1526         BUG_ON(item_size < sizeof(*item));
1527         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1528         flags |= btrfs_extent_flags(l, item);
1529         btrfs_set_extent_flags(l, item, flags);
1530 out:
1531         btrfs_free_path(path);
1532         finish_current_insert(trans, root->fs_info->extent_root);
1533         del_pending_extents(trans, root->fs_info->extent_root);
1534         return ret;
1535 }
1536
1537 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
1538                            struct btrfs_root *root,
1539                            struct extent_buffer *buf,
1540                            int record_parent, int inc)
1541 {
1542         u64 bytenr;
1543         u64 num_bytes;
1544         u64 parent;
1545         u64 ref_root;
1546         u32 nritems;
1547         struct btrfs_key key;
1548         struct btrfs_file_extent_item *fi;
1549         int i;
1550         int level;
1551         int ret = 0;
1552         int faili = 0;
1553         int (*process_func)(struct btrfs_trans_handle *trans,
1554                             struct btrfs_root *root,
1555                             u64, u64, u64, u64, u64, u64);
1556
1557         ref_root = btrfs_header_owner(buf);
1558         nritems = btrfs_header_nritems(buf);
1559         level = btrfs_header_level(buf);
1560
1561         if (!root->ref_cows && level == 0)
1562                 return 0;
1563
1564         if (inc)
1565                 process_func = btrfs_inc_extent_ref;
1566         else
1567                 process_func = btrfs_free_extent;
1568
1569         if (record_parent)
1570                 parent = buf->start;
1571         else
1572                 parent = 0;
1573
1574         for (i = 0; i < nritems; i++) {
1575                 cond_resched();
1576                 if (level == 0) {
1577                         btrfs_item_key_to_cpu(buf, &key, i);
1578                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1579                                 continue;
1580                         fi = btrfs_item_ptr(buf, i,
1581                                             struct btrfs_file_extent_item);
1582                         if (btrfs_file_extent_type(buf, fi) ==
1583                             BTRFS_FILE_EXTENT_INLINE)
1584                                 continue;
1585                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1586                         if (bytenr == 0)
1587                                 continue;
1588
1589                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
1590                         key.offset -= btrfs_file_extent_offset(buf, fi);
1591                         ret = process_func(trans, root, bytenr, num_bytes,
1592                                            parent, ref_root, key.objectid,
1593                                            key.offset);
1594                         if (ret) {
1595                                 faili = i;
1596                                 WARN_ON(1);
1597                                 goto fail;
1598                         }
1599                 } else {
1600                         bytenr = btrfs_node_blockptr(buf, i);
1601                         num_bytes = btrfs_level_size(root, level - 1);
1602                         ret = process_func(trans, root, bytenr, num_bytes,
1603                                            parent, ref_root, level - 1, 0);
1604                         if (ret) {
1605                                 faili = i;
1606                                 WARN_ON(1);
1607                                 goto fail;
1608                         }
1609                 }
1610         }
1611         return 0;
1612 fail:
1613         WARN_ON(1);
1614 #if 0
1615         for (i =0; i < faili; i++) {
1616                 if (level == 0) {
1617                         u64 disk_bytenr;
1618                         btrfs_item_key_to_cpu(buf, &key, i);
1619                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1620                                 continue;
1621                         fi = btrfs_item_ptr(buf, i,
1622                                             struct btrfs_file_extent_item);
1623                         if (btrfs_file_extent_type(buf, fi) ==
1624                             BTRFS_FILE_EXTENT_INLINE)
1625                                 continue;
1626                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1627                         if (disk_bytenr == 0)
1628                                 continue;
1629                         err = btrfs_free_extent(trans, root, disk_bytenr,
1630                                     btrfs_file_extent_disk_num_bytes(buf,
1631                                                                       fi), 0);
1632                         BUG_ON(err);
1633                 } else {
1634                         bytenr = btrfs_node_blockptr(buf, i);
1635                         err = btrfs_free_extent(trans, root, bytenr,
1636                                         btrfs_level_size(root, level - 1), 0);
1637                         BUG_ON(err);
1638                 }
1639         }
1640 #endif
1641         return ret;
1642 }
1643
1644 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1645                   struct extent_buffer *buf, int record_parent)
1646 {
1647         return __btrfs_mod_ref(trans, root, buf, record_parent, 1);
1648 }
1649
1650 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1651                   struct extent_buffer *buf, int record_parent)
1652 {
1653         return __btrfs_mod_ref(trans, root, buf, record_parent, 0);
1654 }
1655
1656 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1657                                  struct btrfs_root *root,
1658                                  struct btrfs_path *path,
1659                                  struct btrfs_block_group_cache *cache)
1660 {
1661         int ret;
1662         int pending_ret;
1663         struct btrfs_root *extent_root = root->fs_info->extent_root;
1664         unsigned long bi;
1665         struct extent_buffer *leaf;
1666
1667         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1668         if (ret < 0)
1669                 goto fail;
1670         BUG_ON(ret);
1671
1672         leaf = path->nodes[0];
1673         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1674         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1675         btrfs_mark_buffer_dirty(leaf);
1676         btrfs_release_path(extent_root, path);
1677 fail:
1678         finish_current_insert(trans, extent_root);
1679         pending_ret = del_pending_extents(trans, extent_root);
1680         if (ret)
1681                 return ret;
1682         if (pending_ret)
1683                 return pending_ret;
1684         return 0;
1685
1686 }
1687
1688 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1689                                    struct btrfs_root *root)
1690 {
1691         struct extent_io_tree *block_group_cache;
1692         struct btrfs_block_group_cache *cache;
1693         int ret;
1694         struct btrfs_path *path;
1695         u64 last = 0;
1696         u64 start;
1697         u64 end;
1698         u64 ptr;
1699
1700         block_group_cache = &root->fs_info->block_group_cache;
1701         path = btrfs_alloc_path();
1702         if (!path)
1703                 return -ENOMEM;
1704
1705         while(1) {
1706                 ret = find_first_extent_bit(block_group_cache, last,
1707                                             &start, &end, BLOCK_GROUP_DIRTY);
1708                 if (ret) {
1709                         if (last == 0)
1710                                 break;
1711                         last = 0;
1712                         continue;
1713                 }
1714
1715                 last = end + 1;
1716                 ret = get_state_private(block_group_cache, start, &ptr);
1717                 BUG_ON(ret);
1718
1719                 clear_extent_bits(block_group_cache, start, end,
1720                                   BLOCK_GROUP_DIRTY, GFP_NOFS);
1721
1722                 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1723                 ret = write_one_cache_group(trans, root, path, cache);
1724                 BUG_ON(ret);
1725         }
1726         btrfs_free_path(path);
1727         return 0;
1728 }
1729
1730 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1731                                                   u64 flags)
1732 {
1733         struct list_head *head = &info->space_info;
1734         struct list_head *cur;
1735         struct btrfs_space_info *found;
1736         list_for_each(cur, head) {
1737                 found = list_entry(cur, struct btrfs_space_info, list);
1738                 if (found->flags == flags)
1739                         return found;
1740         }
1741         return NULL;
1742
1743 }
1744
1745 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1746                              u64 total_bytes, u64 bytes_used,
1747                              struct btrfs_space_info **space_info)
1748 {
1749         struct btrfs_space_info *found;
1750
1751         found = __find_space_info(info, flags);
1752         if (found) {
1753                 found->total_bytes += total_bytes;
1754                 found->bytes_used += bytes_used;
1755                 WARN_ON(found->total_bytes < found->bytes_used);
1756                 *space_info = found;
1757                 return 0;
1758         }
1759         found = kmalloc(sizeof(*found), GFP_NOFS);
1760         if (!found)
1761                 return -ENOMEM;
1762
1763         list_add(&found->list, &info->space_info);
1764         found->flags = flags;
1765         found->total_bytes = total_bytes;
1766         found->bytes_used = bytes_used;
1767         found->bytes_pinned = 0;
1768         found->full = 0;
1769         *space_info = found;
1770         return 0;
1771 }
1772
1773
1774 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1775 {
1776         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1777                                    BTRFS_BLOCK_GROUP_RAID1 |
1778                                    BTRFS_BLOCK_GROUP_DUP);
1779         if (extra_flags) {
1780                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1781                         fs_info->avail_data_alloc_bits |= extra_flags;
1782                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1783                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1784                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1785                         fs_info->avail_system_alloc_bits |= extra_flags;
1786         }
1787 }
1788
1789 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1790                           struct btrfs_root *extent_root, u64 alloc_bytes,
1791                           u64 flags)
1792 {
1793         struct btrfs_space_info *space_info;
1794         u64 thresh;
1795         u64 start;
1796         u64 num_bytes;
1797         int ret;
1798
1799         space_info = __find_space_info(extent_root->fs_info, flags);
1800         if (!space_info) {
1801                 ret = update_space_info(extent_root->fs_info, flags,
1802                                         0, 0, &space_info);
1803                 BUG_ON(ret);
1804         }
1805         BUG_ON(!space_info);
1806
1807         if (space_info->full)
1808                 return 0;
1809
1810         thresh = div_factor(space_info->total_bytes, 7);
1811         if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1812             thresh)
1813                 return 0;
1814
1815         ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1816         if (ret == -ENOSPC) {
1817                 space_info->full = 1;
1818                 return 0;
1819         }
1820
1821         BUG_ON(ret);
1822
1823         ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1824                      BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1825         BUG_ON(ret);
1826         return 0;
1827 }
1828
1829 static int update_block_group(struct btrfs_trans_handle *trans,
1830                               struct btrfs_root *root,
1831                               u64 bytenr, u64 num_bytes, int alloc,
1832                               int mark_free)
1833 {
1834         struct btrfs_block_group_cache *cache;
1835         struct btrfs_fs_info *info = root->fs_info;
1836         u64 total = num_bytes;
1837         u64 old_val;
1838         u64 byte_in_group;
1839         u64 start;
1840         u64 end;
1841
1842         /* block accounting for super block */
1843         old_val = btrfs_super_bytes_used(&info->super_copy);
1844         if (alloc)
1845                 old_val += num_bytes;
1846         else
1847                 old_val -= num_bytes;
1848         btrfs_set_super_bytes_used(&info->super_copy, old_val);
1849
1850         /* block accounting for root item */
1851         old_val = btrfs_root_used(&root->root_item);
1852         if (alloc)
1853                 old_val += num_bytes;
1854         else
1855                 old_val -= num_bytes;
1856         btrfs_set_root_used(&root->root_item, old_val);
1857
1858         while(total) {
1859                 cache = btrfs_lookup_block_group(info, bytenr);
1860                 if (!cache) {
1861                         return -1;
1862                 }
1863                 byte_in_group = bytenr - cache->key.objectid;
1864                 WARN_ON(byte_in_group > cache->key.offset);
1865                 start = cache->key.objectid;
1866                 end = start + cache->key.offset - 1;
1867                 set_extent_bits(&info->block_group_cache, start, end,
1868                                 BLOCK_GROUP_DIRTY, GFP_NOFS);
1869
1870                 old_val = btrfs_block_group_used(&cache->item);
1871                 num_bytes = min(total, cache->key.offset - byte_in_group);
1872                 if (alloc) {
1873                         old_val += num_bytes;
1874                         cache->space_info->bytes_used += num_bytes;
1875                 } else {
1876                         old_val -= num_bytes;
1877                         cache->space_info->bytes_used -= num_bytes;
1878                         if (mark_free) {
1879                                 set_extent_dirty(&info->free_space_cache,
1880                                                  bytenr, bytenr + num_bytes - 1,
1881                                                  GFP_NOFS);
1882                         }
1883                 }
1884                 btrfs_set_block_group_used(&cache->item, old_val);
1885                 total -= num_bytes;
1886                 bytenr += num_bytes;
1887         }
1888         return 0;
1889 }
1890
1891 static int update_pinned_extents(struct btrfs_root *root,
1892                                 u64 bytenr, u64 num, int pin)
1893 {
1894         u64 len;
1895         struct btrfs_block_group_cache *cache;
1896         struct btrfs_fs_info *fs_info = root->fs_info;
1897
1898         if (pin) {
1899                 set_extent_dirty(&fs_info->pinned_extents,
1900                                 bytenr, bytenr + num - 1, GFP_NOFS);
1901         } else {
1902                 clear_extent_dirty(&fs_info->pinned_extents,
1903                                 bytenr, bytenr + num - 1, GFP_NOFS);
1904         }
1905         while (num > 0) {
1906                 cache = btrfs_lookup_block_group(fs_info, bytenr);
1907                 WARN_ON(!cache);
1908                 len = min(num, cache->key.offset -
1909                           (bytenr - cache->key.objectid));
1910                 if (pin) {
1911                         cache->pinned += len;
1912                         cache->space_info->bytes_pinned += len;
1913                         fs_info->total_pinned += len;
1914                 } else {
1915                         cache->pinned -= len;
1916                         cache->space_info->bytes_pinned -= len;
1917                         fs_info->total_pinned -= len;
1918                 }
1919                 bytenr += len;
1920                 num -= len;
1921         }
1922         return 0;
1923 }
1924
1925 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1926 {
1927         u64 last = 0;
1928         u64 start;
1929         u64 end;
1930         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1931         int ret;
1932
1933         while(1) {
1934                 ret = find_first_extent_bit(pinned_extents, last,
1935                                             &start, &end, EXTENT_DIRTY);
1936                 if (ret)
1937                         break;
1938                 set_extent_dirty(copy, start, end, GFP_NOFS);
1939                 last = end + 1;
1940         }
1941         return 0;
1942 }
1943
1944 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1945                                struct btrfs_root *root,
1946                                struct extent_io_tree *unpin)
1947 {
1948         u64 start;
1949         u64 end;
1950         int ret;
1951         struct extent_io_tree *free_space_cache;
1952         free_space_cache = &root->fs_info->free_space_cache;
1953
1954         while(1) {
1955                 ret = find_first_extent_bit(unpin, 0, &start, &end,
1956                                             EXTENT_DIRTY);
1957                 if (ret)
1958                         break;
1959                 update_pinned_extents(root, start, end + 1 - start, 0);
1960                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1961                 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1962         }
1963         return 0;
1964 }
1965
1966 static int finish_current_insert(struct btrfs_trans_handle *trans,
1967                                  struct btrfs_root *extent_root)
1968 {
1969         u64 start;
1970         u64 end;
1971         u64 priv;
1972         struct btrfs_fs_info *info = extent_root->fs_info;
1973         struct btrfs_path *path;
1974         struct pending_extent_op *extent_op;
1975         struct btrfs_key key;
1976         int ret;
1977
1978         path = btrfs_alloc_path();
1979
1980         while(1) {
1981                 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1982                                             &end, EXTENT_LOCKED);
1983                 if (ret)
1984                         break;
1985
1986                 ret = get_state_private(&info->extent_ins, start, &priv);
1987                 BUG_ON(ret);
1988                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1989
1990                 if (extent_op->type == PENDING_EXTENT_INSERT) {
1991                         key.objectid = start;
1992                         key.offset = end + 1 - start;
1993                         key.type = BTRFS_EXTENT_ITEM_KEY;
1994                         ret = alloc_reserved_tree_block(trans, extent_root,
1995                                                 extent_root->root_key.objectid,
1996                                                 trans->transid,
1997                                                 extent_op->flags,
1998                                                 &extent_op->key,
1999                                                 extent_op->level, &key);
2000                 } else {
2001                         BUG_ON(1);
2002                 }
2003
2004                 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
2005                                   GFP_NOFS);
2006                 kfree(extent_op);
2007         }
2008         btrfs_free_path(path);
2009         return 0;
2010 }
2011
2012 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2013                           struct btrfs_root *root,
2014                           u64 bytenr, u64 num_bytes, int is_data)
2015 {
2016         int err = 0;
2017         struct extent_buffer *buf;
2018
2019         if (is_data)
2020                 goto pinit;
2021
2022         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2023         if (!buf)
2024                 goto pinit;
2025
2026         /* we can reuse a block if it hasn't been written
2027          * and it is from this transaction.  We can't
2028          * reuse anything from the tree log root because
2029          * it has tiny sub-transactions.
2030          */
2031         if (btrfs_buffer_uptodate(buf, 0)) {
2032                 u64 header_owner = btrfs_header_owner(buf);
2033                 u64 header_transid = btrfs_header_generation(buf);
2034                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2035                     header_transid == trans->transid &&
2036                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2037                         clean_tree_block(NULL, root, buf);
2038                         free_extent_buffer(buf);
2039                         return 1;
2040                 }
2041         }
2042         free_extent_buffer(buf);
2043 pinit:
2044         update_pinned_extents(root, bytenr, num_bytes, 1);
2045
2046         BUG_ON(err < 0);
2047         return 0;
2048 }
2049
2050 /*
2051  * remove an extent from the root, returns 0 on success
2052  */
2053 static int __free_extent(struct btrfs_trans_handle *trans,
2054                          struct btrfs_root *root,
2055                          u64 bytenr, u64 num_bytes, u64 parent,
2056                          u64 root_objectid, u64 owner_objectid,
2057                          u64 owner_offset, int refs_to_drop)
2058 {
2059
2060         struct btrfs_key key;
2061         struct btrfs_path *path;
2062         struct btrfs_extent_ops *ops = root->fs_info->extent_ops;
2063         struct btrfs_root *extent_root = root->fs_info->extent_root;
2064         struct extent_buffer *leaf;
2065         struct btrfs_extent_item *ei;
2066         struct btrfs_extent_inline_ref *iref;
2067         int ret;
2068         int is_data;
2069         int extent_slot = 0;
2070         int found_extent = 0;
2071         int num_to_del = 1;
2072         u32 item_size;
2073         u64 refs;
2074
2075         path = btrfs_alloc_path();
2076         if (!path)
2077                 return -ENOMEM;
2078
2079         path->reada = 1;
2080         path->leave_spinning = 1;
2081
2082         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2083         BUG_ON(!is_data && refs_to_drop != 1);
2084
2085         ret = lookup_extent_backref(trans, extent_root, path, &iref,
2086                                     bytenr, num_bytes, parent,
2087                                     root_objectid, owner_objectid,
2088                                     owner_offset);
2089         if (ret == 0) {
2090                 extent_slot = path->slots[0];
2091                 while (extent_slot >= 0) {
2092                         btrfs_item_key_to_cpu(path->nodes[0], &key,
2093                                               extent_slot);
2094                         if (key.objectid != bytenr)
2095                                 break;
2096                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2097                             key.offset == num_bytes) {
2098                                 found_extent = 1;
2099                                 break;
2100                         }
2101                         if (path->slots[0] - extent_slot > 5)
2102                                 break;
2103                         extent_slot--;
2104                 }
2105 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2106                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
2107                 if (found_extent && item_size < sizeof(*ei))
2108                         found_extent = 0;
2109 #endif
2110                 if (!found_extent) {
2111                         BUG_ON(iref);
2112                         ret = remove_extent_backref(trans, extent_root, path,
2113                                                     NULL, refs_to_drop,
2114                                                     is_data);
2115                         BUG_ON(ret);
2116                         btrfs_release_path(extent_root, path);
2117                         path->leave_spinning = 1;
2118
2119                         key.objectid = bytenr;
2120                         key.type = BTRFS_EXTENT_ITEM_KEY;
2121                         key.offset = num_bytes;
2122
2123                         ret = btrfs_search_slot(trans, extent_root,
2124                                                 &key, path, -1, 1);
2125                         if (ret) {
2126                                 printk(KERN_ERR "umm, got %d back from search"
2127                                        ", was looking for %llu\n", ret,
2128                                        (unsigned long long)bytenr);
2129                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2130                         }
2131                         BUG_ON(ret);
2132                         extent_slot = path->slots[0];
2133                 }
2134         } else {
2135                 btrfs_print_leaf(extent_root, path->nodes[0]);
2136                 WARN_ON(1);
2137                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2138                        "parent %llu root %llu  owner %llu offset %llu\n",
2139                        (unsigned long long)bytenr,
2140                        (unsigned long long)parent,
2141                        (unsigned long long)root_objectid,
2142                        (unsigned long long)owner_objectid,
2143                        (unsigned long long)owner_offset);
2144         }
2145
2146         leaf = path->nodes[0];
2147         item_size = btrfs_item_size_nr(leaf, extent_slot);
2148 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2149         if (item_size < sizeof(*ei)) {
2150                 BUG_ON(found_extent || extent_slot != path->slots[0]);
2151                 ret = convert_extent_item_v0(trans, extent_root, path,
2152                                              owner_objectid, 0);
2153                 BUG_ON(ret < 0);
2154
2155                 btrfs_release_path(extent_root, path);
2156                 path->leave_spinning = 1;
2157
2158                 key.objectid = bytenr;
2159                 key.type = BTRFS_EXTENT_ITEM_KEY;
2160                 key.offset = num_bytes;
2161
2162                 ret = btrfs_search_slot(trans, extent_root, &key, path,
2163                                         -1, 1);
2164                 if (ret) {
2165                         printk(KERN_ERR "umm, got %d back from search"
2166                                ", was looking for %llu\n", ret,
2167                                (unsigned long long)bytenr);
2168                         btrfs_print_leaf(extent_root, path->nodes[0]);
2169                 }
2170                 BUG_ON(ret);
2171                 extent_slot = path->slots[0];
2172                 leaf = path->nodes[0];
2173                 item_size = btrfs_item_size_nr(leaf, extent_slot);
2174         }
2175 #endif
2176         BUG_ON(item_size < sizeof(*ei));
2177         ei = btrfs_item_ptr(leaf, extent_slot,
2178                             struct btrfs_extent_item);
2179         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2180                 struct btrfs_tree_block_info *bi;
2181                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
2182                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2183                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
2184         }
2185
2186         refs = btrfs_extent_refs(leaf, ei);
2187         BUG_ON(refs < refs_to_drop);
2188         refs -= refs_to_drop;
2189
2190         if (refs > 0) {
2191                 /*
2192                  * In the case of inline back ref, reference count will
2193                  * be updated by remove_extent_backref
2194                  */
2195                 if (iref) {
2196                         BUG_ON(!found_extent);
2197                 } else {
2198                         btrfs_set_extent_refs(leaf, ei, refs);
2199                         btrfs_mark_buffer_dirty(leaf);
2200                 }
2201                 if (found_extent) {
2202                         ret = remove_extent_backref(trans, extent_root, path,
2203                                                     iref, refs_to_drop,
2204                                                     is_data);
2205                         BUG_ON(ret);
2206                 }
2207         } else {
2208                 int mark_free = 0;
2209                 int pin = 1;
2210
2211                 if (found_extent) {
2212                         BUG_ON(is_data && refs_to_drop !=
2213                                extent_data_ref_count(root, path, iref));
2214                         if (iref) {
2215                                 BUG_ON(path->slots[0] != extent_slot);
2216                         } else {
2217                                 BUG_ON(path->slots[0] != extent_slot + 1);
2218                                 path->slots[0] = extent_slot;
2219                                 num_to_del = 2;
2220                         }
2221                 }
2222
2223                 if (ops && ops->free_extent) {
2224                         ret = ops->free_extent(root, bytenr, num_bytes);
2225                         if (ret > 0) {
2226                                 pin = 0;
2227                                 mark_free = 0;
2228                         }
2229                 }
2230
2231                 if (pin) {
2232                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
2233                                              is_data);
2234                         if (ret > 0)
2235                                 mark_free = 1;
2236                         BUG_ON(ret < 0);
2237                 }
2238
2239                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2240                                       num_to_del);
2241                 BUG_ON(ret);
2242                 btrfs_release_path(extent_root, path);
2243
2244                 if (is_data) {
2245                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2246                         BUG_ON(ret);
2247                 }
2248
2249                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
2250                                          mark_free);
2251                 BUG_ON(ret);
2252         }
2253         btrfs_free_path(path);
2254         finish_current_insert(trans, extent_root);
2255         return ret;
2256 }
2257
2258 /*
2259  * find all the blocks marked as pending in the radix tree and remove
2260  * them from the extent map
2261  */
2262 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
2263                                btrfs_root *extent_root)
2264 {
2265         int ret;
2266         int err = 0;
2267         u64 start;
2268         u64 end;
2269         u64 priv;
2270         struct extent_io_tree *pending_del;
2271         struct extent_io_tree *extent_ins;
2272         struct pending_extent_op *extent_op;
2273
2274         extent_ins = &extent_root->fs_info->extent_ins;
2275         pending_del = &extent_root->fs_info->pending_del;
2276
2277         while(1) {
2278                 ret = find_first_extent_bit(pending_del, 0, &start, &end,
2279                                             EXTENT_LOCKED);
2280                 if (ret)
2281                         break;
2282
2283                 ret = get_state_private(pending_del, start, &priv);
2284                 BUG_ON(ret);
2285                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2286
2287                 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
2288                                   GFP_NOFS);
2289
2290                 if (!test_range_bit(extent_ins, start, end,
2291                                     EXTENT_LOCKED, 0)) {
2292                         ret = __free_extent(trans, extent_root,
2293                                             start, end + 1 - start, 0,
2294                                             extent_root->root_key.objectid,
2295                                             extent_op->level, 0, 1);
2296                         kfree(extent_op);
2297                 } else {
2298                         kfree(extent_op);
2299                         ret = get_state_private(extent_ins, start, &priv);
2300                         BUG_ON(ret);
2301                         extent_op = (struct pending_extent_op *)
2302                                                         (unsigned long)priv;
2303
2304                         clear_extent_bits(extent_ins, start, end,
2305                                           EXTENT_LOCKED, GFP_NOFS);
2306
2307                         if (extent_op->type == PENDING_BACKREF_UPDATE)
2308                                 BUG_ON(1);
2309
2310                         kfree(extent_op);
2311                 }
2312                 if (ret)
2313                         err = ret;
2314         }
2315         return err;
2316 }
2317
2318 /*
2319  * remove an extent from the root, returns 0 on success
2320  */
2321
2322 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2323                       struct btrfs_root *root,
2324                       u64 bytenr, u64 num_bytes, u64 parent,
2325                       u64 root_objectid, u64 owner, u64 offset)
2326 {
2327         struct btrfs_root *extent_root = root->fs_info->extent_root;
2328         int pending_ret;
2329         int ret;
2330
2331         WARN_ON(num_bytes < root->sectorsize);
2332         if (root == extent_root) {
2333                 struct pending_extent_op *extent_op;
2334
2335                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2336                 BUG_ON(!extent_op);
2337
2338                 extent_op->type = PENDING_EXTENT_DELETE;
2339                 extent_op->bytenr = bytenr;
2340                 extent_op->num_bytes = num_bytes;
2341                 extent_op->level = (int)owner;
2342
2343                 set_extent_bits(&root->fs_info->pending_del,
2344                                 bytenr, bytenr + num_bytes - 1,
2345                                 EXTENT_LOCKED, GFP_NOFS);
2346                 set_state_private(&root->fs_info->pending_del,
2347                                   bytenr, (unsigned long)extent_op);
2348                 return 0;
2349         }
2350         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2351                             root_objectid, owner, offset, 1);
2352         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
2353         return ret ? ret : pending_ret;
2354 }
2355
2356 static u64 stripe_align(struct btrfs_root *root, u64 val)
2357 {
2358         u64 mask = ((u64)root->stripesize - 1);
2359         u64 ret = (val + mask) & ~mask;
2360         return ret;
2361 }
2362
2363 /*
2364  * walks the btree of allocated extents and find a hole of a given size.
2365  * The key ins is changed to record the hole:
2366  * ins->objectid == block start
2367  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2368  * ins->offset == number of blocks
2369  * Any available blocks before search_start are skipped.
2370  */
2371 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
2372                                      struct btrfs_root *orig_root,
2373                                      u64 num_bytes, u64 empty_size,
2374                                      u64 search_start, u64 search_end,
2375                                      u64 hint_byte, struct btrfs_key *ins,
2376                                      u64 exclude_start, u64 exclude_nr,
2377                                      int data)
2378 {
2379         int ret;
2380         u64 orig_search_start = search_start;
2381         struct btrfs_root * root = orig_root->fs_info->extent_root;
2382         struct btrfs_fs_info *info = root->fs_info;
2383         u64 total_needed = num_bytes;
2384         struct btrfs_block_group_cache *block_group;
2385         int full_scan = 0;
2386         int wrapped = 0;
2387
2388         WARN_ON(num_bytes < root->sectorsize);
2389         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2390
2391         if (hint_byte) {
2392                 block_group = btrfs_lookup_first_block_group(info, hint_byte);
2393                 if (!block_group)
2394                         hint_byte = search_start;
2395                 block_group = btrfs_find_block_group(root, block_group,
2396                                                      hint_byte, data, 1);
2397         } else {
2398                 block_group = btrfs_find_block_group(root,
2399                                                      trans->block_group,
2400                                                      search_start, data, 1);
2401         }
2402
2403         total_needed += empty_size;
2404
2405 check_failed:
2406         if (!block_group) {
2407                 block_group = btrfs_lookup_first_block_group(info,
2408                                                              search_start);
2409                 if (!block_group)
2410                         block_group = btrfs_lookup_first_block_group(info,
2411                                                        orig_search_start);
2412         }
2413         ret = find_search_start(root, &block_group, &search_start,
2414                                 total_needed, data);
2415         if (ret)
2416                 goto error;
2417
2418         search_start = stripe_align(root, search_start);
2419         ins->objectid = search_start;
2420         ins->offset = num_bytes;
2421
2422         if (ins->objectid + num_bytes >
2423             block_group->key.objectid + block_group->key.offset) {
2424                 search_start = block_group->key.objectid +
2425                         block_group->key.offset;
2426                 goto new_group;
2427         }
2428
2429         if (test_range_bit(&info->extent_ins, ins->objectid,
2430                            ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
2431                 search_start = ins->objectid + num_bytes;
2432                 goto new_group;
2433         }
2434
2435         if (test_range_bit(&info->pinned_extents, ins->objectid,
2436                            ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
2437                 search_start = ins->objectid + num_bytes;
2438                 goto new_group;
2439         }
2440
2441         if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
2442             ins->objectid < exclude_start + exclude_nr)) {
2443                 search_start = exclude_start + exclude_nr;
2444                 goto new_group;
2445         }
2446
2447         if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
2448                 block_group = btrfs_lookup_block_group(info, ins->objectid);
2449                 if (block_group)
2450                         trans->block_group = block_group;
2451         }
2452         ins->offset = num_bytes;
2453         return 0;
2454
2455 new_group:
2456         block_group = btrfs_lookup_first_block_group(info, search_start);
2457         if (!block_group) {
2458                 search_start = orig_search_start;
2459                 if (full_scan) {
2460                         ret = -ENOSPC;
2461                         goto error;
2462                 }
2463                 if (wrapped) {
2464                         if (!full_scan)
2465                                 total_needed -= empty_size;
2466                         full_scan = 1;
2467                 } else
2468                         wrapped = 1;
2469         }
2470         cond_resched();
2471         block_group = btrfs_find_block_group(root, block_group,
2472                                              search_start, data, 0);
2473         goto check_failed;
2474
2475 error:
2476         return ret;
2477 }
2478
2479 static int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
2480                                 struct btrfs_root *root,
2481                                 u64 num_bytes, u64 empty_size,
2482                                 u64 hint_byte, u64 search_end,
2483                                 struct btrfs_key *ins, int data)
2484 {
2485         int ret;
2486         u64 search_start = 0;
2487         u64 alloc_profile;
2488         struct btrfs_fs_info *info = root->fs_info;
2489
2490         if (info->extent_ops) {
2491                 struct btrfs_extent_ops *ops = info->extent_ops;
2492                 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
2493                 BUG_ON(ret);
2494                 goto found;
2495         }
2496
2497         if (data) {
2498                 alloc_profile = info->avail_data_alloc_bits &
2499                                 info->data_alloc_profile;
2500                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2501         } else if ((info->system_allocs > 0 || root == info->chunk_root) &&
2502                    info->system_allocs >= 0) {
2503                 alloc_profile = info->avail_system_alloc_bits &
2504                                 info->system_alloc_profile;
2505                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2506         } else {
2507                 alloc_profile = info->avail_metadata_alloc_bits &
2508                                 info->metadata_alloc_profile;
2509                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2510         }
2511
2512         if (root->ref_cows) {
2513                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
2514                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2515                                              num_bytes,
2516                                              BTRFS_BLOCK_GROUP_METADATA);
2517                         BUG_ON(ret);
2518                 }
2519                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2520                                      num_bytes + 2 * 1024 * 1024, data);
2521                 BUG_ON(ret);
2522         }
2523
2524         WARN_ON(num_bytes < root->sectorsize);
2525         ret = find_free_extent(trans, root, num_bytes, empty_size,
2526                                search_start, search_end, hint_byte, ins,
2527                                trans->alloc_exclude_start,
2528                                trans->alloc_exclude_nr, data);
2529         BUG_ON(ret);
2530 found:
2531         clear_extent_dirty(&root->fs_info->free_space_cache,
2532                            ins->objectid, ins->objectid + ins->offset - 1,
2533                            GFP_NOFS);
2534         return ret;
2535 }
2536
2537 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
2538                                      struct btrfs_root *root,
2539                                      u64 root_objectid, u64 generation,
2540                                      u64 flags, struct btrfs_disk_key *key,
2541                                      int level, struct btrfs_key *ins)
2542 {
2543         int ret;
2544         struct btrfs_fs_info *fs_info = root->fs_info;
2545         struct btrfs_extent_item *extent_item;
2546         struct btrfs_tree_block_info *block_info;
2547         struct btrfs_extent_inline_ref *iref;
2548         struct btrfs_path *path;
2549         struct extent_buffer *leaf;
2550         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
2551
2552         path = btrfs_alloc_path();
2553         BUG_ON(!path);
2554
2555         path->leave_spinning = 1;
2556         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
2557                                       ins, size);
2558         BUG_ON(ret);
2559
2560         leaf = path->nodes[0];
2561         extent_item = btrfs_item_ptr(leaf, path->slots[0],
2562                                      struct btrfs_extent_item);
2563         btrfs_set_extent_refs(leaf, extent_item, 1);
2564         btrfs_set_extent_generation(leaf, extent_item, generation);
2565         btrfs_set_extent_flags(leaf, extent_item,
2566                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
2567         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
2568
2569         btrfs_set_tree_block_key(leaf, block_info, key);
2570         btrfs_set_tree_block_level(leaf, block_info, level);
2571
2572         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
2573         btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_TREE_BLOCK_REF_KEY);
2574         btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
2575
2576         btrfs_mark_buffer_dirty(leaf);
2577         btrfs_free_path(path);
2578
2579         ret = update_block_group(trans, root, ins->objectid, ins->offset,
2580                                  1, 0);
2581         if (ret) {
2582                 printk(KERN_ERR "btrfs update block group failed for %llu "
2583                        "%llu\n", (unsigned long long)ins->objectid,
2584                        (unsigned long long)ins->offset);
2585                 BUG();
2586         }
2587         return ret;
2588 }
2589
2590 static int alloc_tree_block(struct btrfs_trans_handle *trans,
2591                             struct btrfs_root *root, u64 num_bytes,
2592                             u64 root_objectid, u64 generation,
2593                             u64 flags, struct btrfs_disk_key *key,
2594                             int level, u64 empty_size, u64 hint_byte,
2595                             u64 search_end, struct btrfs_key *ins)
2596 {
2597         int ret;
2598         ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
2599                                    hint_byte, search_end, ins, 0);
2600         BUG_ON(ret);
2601
2602         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID) {
2603                 struct pending_extent_op *extent_op;
2604
2605                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2606                 BUG_ON(!extent_op);
2607
2608                 extent_op->type = PENDING_EXTENT_INSERT;
2609                 extent_op->bytenr = ins->objectid;
2610                 extent_op->num_bytes = ins->offset;
2611                 extent_op->level = level;
2612                 extent_op->flags = flags;
2613                 memcpy(&extent_op->key, key, sizeof(*key));
2614
2615                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
2616                                 ins->objectid + ins->offset - 1,
2617                                 EXTENT_LOCKED, GFP_NOFS);
2618                 set_state_private(&root->fs_info->extent_ins,
2619                                   ins->objectid, (unsigned long)extent_op);
2620         } else {
2621                 ret = alloc_reserved_tree_block(trans, root, root_objectid,
2622                                                 generation, flags,
2623                                                 key, level, ins);
2624                 finish_current_insert(trans, root->fs_info->extent_root);
2625                 del_pending_extents(trans, root->fs_info->extent_root);
2626         }
2627         return ret;
2628 }
2629
2630 /*
2631  * helper function to allocate a block for a given tree
2632  * returns the tree buffer or NULL.
2633  */
2634 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
2635                                         struct btrfs_root *root,
2636                                         u32 blocksize, u64 root_objectid,
2637                                         struct btrfs_disk_key *key, int level,
2638                                         u64 hint, u64 empty_size)
2639 {
2640         struct btrfs_key ins;
2641         int ret;
2642         struct extent_buffer *buf;
2643
2644         ret = alloc_tree_block(trans, root, blocksize, root_objectid,
2645                                trans->transid, 0, key, level,
2646                                empty_size, hint, (u64)-1, &ins);
2647         if (ret) {
2648                 BUG_ON(ret > 0);
2649                 return ERR_PTR(ret);
2650         }
2651
2652         buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2653         if (!buf) {
2654                 btrfs_free_extent(trans, root, ins.objectid, ins.offset,
2655                                   0, root->root_key.objectid, level, 0);
2656                 BUG_ON(1);
2657                 return ERR_PTR(-ENOMEM);
2658         }
2659         btrfs_set_buffer_uptodate(buf);
2660         trans->blocks_used++;
2661
2662         return buf;
2663 }
2664
2665 #if 0
2666
2667 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2668                                   struct btrfs_root *root,
2669                                   struct extent_buffer *leaf)
2670 {
2671         u64 leaf_owner;
2672         u64 leaf_generation;
2673         struct btrfs_key key;
2674         struct btrfs_file_extent_item *fi;
2675         int i;
2676         int nritems;
2677         int ret;
2678
2679         BUG_ON(!btrfs_is_leaf(leaf));
2680         nritems = btrfs_header_nritems(leaf);
2681         leaf_owner = btrfs_header_owner(leaf);
2682         leaf_generation = btrfs_header_generation(leaf);
2683
2684         for (i = 0; i < nritems; i++) {
2685                 u64 disk_bytenr;
2686
2687                 btrfs_item_key_to_cpu(leaf, &key, i);
2688                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2689                         continue;
2690                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2691                 if (btrfs_file_extent_type(leaf, fi) ==
2692                     BTRFS_FILE_EXTENT_INLINE)
2693                         continue;
2694                 /*
2695                  * FIXME make sure to insert a trans record that
2696                  * repeats the snapshot del on crash
2697                  */
2698                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2699                 if (disk_bytenr == 0)
2700                         continue;
2701                 ret = btrfs_free_extent(trans, root, disk_bytenr,
2702                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
2703                                 leaf->start, leaf_owner, leaf_generation,
2704                                 key.objectid, 0);
2705                 BUG_ON(ret);
2706         }
2707         return 0;
2708 }
2709
2710 static void noinline reada_walk_down(struct btrfs_root *root,
2711                                      struct extent_buffer *node,
2712                                      int slot)
2713 {
2714         u64 bytenr;
2715         u64 last = 0;
2716         u32 nritems;
2717         u32 refs;
2718         u32 blocksize;
2719         int ret;
2720         int i;
2721         int level;
2722         int skipped = 0;
2723
2724         nritems = btrfs_header_nritems(node);
2725         level = btrfs_header_level(node);
2726         if (level)
2727                 return;
2728
2729         for (i = slot; i < nritems && skipped < 32; i++) {
2730                 bytenr = btrfs_node_blockptr(node, i);
2731                 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2732                              (last > bytenr && last - bytenr > 32 * 1024))) {
2733                         skipped++;
2734                         continue;
2735                 }
2736                 blocksize = btrfs_level_size(root, level - 1);
2737                 if (i != slot) {
2738                         ret = btrfs_lookup_extent_ref(NULL, root, bytenr,
2739                                                       blocksize, &refs);
2740                         BUG_ON(ret);
2741                         if (refs != 1) {
2742                                 skipped++;
2743                                 continue;
2744                         }
2745                 }
2746                 mutex_unlock(&root->fs_info->fs_mutex);
2747                 ret = readahead_tree_block(root, bytenr, blocksize,
2748                                            btrfs_node_ptr_generation(node, i));
2749                 last = bytenr + blocksize;
2750                 cond_resched();
2751                 mutex_lock(&root->fs_info->fs_mutex);
2752                 if (ret)
2753                         break;
2754         }
2755 }
2756
2757 /*
2758  * helper function for drop_snapshot, this walks down the tree dropping ref
2759  * counts as it goes.
2760  */
2761 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2762                                    struct btrfs_root *root,
2763                                    struct btrfs_path *path, int *level)
2764 {
2765         u64 root_owner;
2766         u64 root_gen;
2767         u64 bytenr;
2768         u64 ptr_gen;
2769         struct extent_buffer *next;
2770         struct extent_buffer *cur;
2771         struct extent_buffer *parent;
2772         u32 blocksize;
2773         int ret;
2774         u32 refs;
2775
2776         WARN_ON(*level < 0);
2777         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2778         ret = btrfs_lookup_extent_ref(trans, root,
2779                                       path->nodes[*level]->start,
2780                                       path->nodes[*level]->len, &refs);
2781         BUG_ON(ret);
2782         if (refs > 1)
2783                 goto out;
2784
2785         /*
2786          * walk down to the last node level and free all the leaves
2787          */
2788         while(*level >= 0) {
2789                 WARN_ON(*level < 0);
2790                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2791                 cur = path->nodes[*level];
2792
2793                 if (btrfs_header_level(cur) != *level)
2794                         WARN_ON(1);
2795
2796                 if (path->slots[*level] >=
2797                     btrfs_header_nritems(cur))
2798                         break;
2799                 if (*level == 0) {
2800                         ret = drop_leaf_ref(trans, root, cur);
2801                         BUG_ON(ret);
2802                         break;
2803                 }
2804                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2805                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2806                 blocksize = btrfs_level_size(root, *level - 1);
2807                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
2808                                               &refs);
2809                 BUG_ON(ret);
2810                 if (refs != 1) {
2811                         parent = path->nodes[*level];
2812                         root_owner = btrfs_header_owner(parent);
2813                         root_gen = btrfs_header_generation(parent);
2814                         path->slots[*level]++;
2815                         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
2816                                                 parent->start, root_owner,
2817                                                 root_gen, *level - 1, 1);
2818                         BUG_ON(ret);
2819                         continue;
2820                 }
2821                 next = btrfs_find_tree_block(root, bytenr, blocksize);
2822                 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2823                         free_extent_buffer(next);
2824                         reada_walk_down(root, cur, path->slots[*level]);
2825                         mutex_unlock(&root->fs_info->fs_mutex);
2826                         next = read_tree_block(root, bytenr, blocksize,
2827                                                ptr_gen);
2828                         mutex_lock(&root->fs_info->fs_mutex);
2829                 }
2830                 WARN_ON(*level <= 0);
2831                 if (path->nodes[*level-1])
2832                         free_extent_buffer(path->nodes[*level-1]);
2833                 path->nodes[*level-1] = next;
2834                 *level = btrfs_header_level(next);
2835                 path->slots[*level] = 0;
2836         }
2837 out:
2838         WARN_ON(*level < 0);
2839         WARN_ON(*level >= BTRFS_MAX_LEVEL);
2840
2841         if (path->nodes[*level] == root->node) {
2842                 root_owner = root->root_key.objectid;
2843                 parent = path->nodes[*level];
2844         } else {
2845                 parent = path->nodes[*level + 1];
2846                 root_owner = btrfs_header_owner(parent);
2847         }
2848
2849         root_gen = btrfs_header_generation(parent);
2850         ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2851                                 path->nodes[*level]->len, parent->start,
2852                                 root_owner, root_gen, *level, 1);
2853         free_extent_buffer(path->nodes[*level]);
2854         path->nodes[*level] = NULL;
2855         *level += 1;
2856         BUG_ON(ret);
2857         return 0;
2858 }
2859
2860 /*
2861  * helper for dropping snapshots.  This walks back up the tree in the path
2862  * to find the first node higher up where we haven't yet gone through
2863  * all the slots
2864  */
2865 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2866                                  struct btrfs_root *root,
2867                                  struct btrfs_path *path, int *level)
2868 {
2869         u64 root_owner;
2870         u64 root_gen;
2871         struct btrfs_root_item *root_item = &root->root_item;
2872         int i;
2873         int slot;
2874         int ret;
2875
2876         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2877                 slot = path->slots[i];
2878                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2879                         struct extent_buffer *node;
2880                         struct btrfs_disk_key disk_key;
2881                         node = path->nodes[i];
2882                         path->slots[i]++;
2883                         *level = i;
2884                         WARN_ON(*level == 0);
2885                         btrfs_node_key(node, &disk_key, path->slots[i]);
2886                         memcpy(&root_item->drop_progress,
2887                                &disk_key, sizeof(disk_key));
2888                         root_item->drop_level = i;
2889                         return 0;
2890                 } else {
2891                         struct extent_buffer *parent;
2892                         if (path->nodes[*level] == root->node)
2893                                 parent = path->nodes[*level];
2894                         else
2895                                 parent = path->nodes[*level + 1];
2896
2897                         root_owner = btrfs_header_owner(parent);
2898                         root_gen = btrfs_header_generation(parent);
2899                         ret = btrfs_free_extent(trans, root,
2900                                                 path->nodes[*level]->start,
2901                                                 path->nodes[*level]->len,
2902                                                 parent->start, root_owner,
2903                                                 root_gen, *level, 1);
2904                         BUG_ON(ret);
2905                         free_extent_buffer(path->nodes[*level]);
2906                         path->nodes[*level] = NULL;
2907                         *level = i + 1;
2908                 }
2909         }
2910         return 1;
2911 }
2912
2913 /*
2914  * drop the reference count on the tree rooted at 'snap'.  This traverses
2915  * the tree freeing any blocks that have a ref count of zero after being
2916  * decremented.
2917  */
2918 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2919                         *root)
2920 {
2921         int ret = 0;
2922         int wret;
2923         int level;
2924         struct btrfs_path *path;
2925         int i;
2926         int orig_level;
2927         struct btrfs_root_item *root_item = &root->root_item;
2928
2929         path = btrfs_alloc_path();
2930         BUG_ON(!path);
2931
2932         level = btrfs_header_level(root->node);
2933         orig_level = level;
2934         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2935                 path->nodes[level] = root->node;
2936                 extent_buffer_get(root->node);
2937                 path->slots[level] = 0;
2938         } else {
2939                 struct btrfs_key key;
2940                 struct btrfs_disk_key found_key;
2941                 struct extent_buffer *node;
2942
2943                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2944                 level = root_item->drop_level;
2945                 path->lowest_level = level;
2946                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2947                 if (wret < 0) {
2948                         ret = wret;
2949                         goto out;
2950                 }
2951                 node = path->nodes[level];
2952                 btrfs_node_key(node, &found_key, path->slots[level]);
2953                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2954                                sizeof(found_key)));
2955         }
2956         while(1) {
2957                 wret = walk_down_tree(trans, root, path, &level);
2958                 if (wret < 0)
2959                         ret = wret;
2960                 if (wret != 0)
2961                         break;
2962
2963                 wret = walk_up_tree(trans, root, path, &level);
2964                 if (wret < 0)
2965                         ret = wret;
2966                 if (wret != 0)
2967                         break;
2968                 /*
2969                 ret = -EAGAIN;
2970                 break;
2971                 */
2972         }
2973         for (i = 0; i <= orig_level; i++) {
2974                 if (path->nodes[i]) {
2975                         free_extent_buffer(path->nodes[i]);
2976                         path->nodes[i] = NULL;
2977                 }
2978         }
2979 out:
2980         btrfs_free_path(path);
2981         return ret;
2982 }
2983
2984 #endif
2985
2986 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2987 {
2988         u64 start;
2989         u64 end;
2990         u64 ptr;
2991         int ret;
2992         while(1) {
2993                 ret = find_first_extent_bit(&info->block_group_cache, 0,
2994                                             &start, &end, (unsigned int)-1);
2995                 if (ret)
2996                         break;
2997                 ret = get_state_private(&info->block_group_cache, start, &ptr);
2998                 if (!ret)
2999                         kfree((void *)(unsigned long)ptr);
3000                 clear_extent_bits(&info->block_group_cache, start,
3001                                   end, (unsigned int)-1, GFP_NOFS);
3002         }
3003         while(1) {
3004                 ret = find_first_extent_bit(&info->free_space_cache, 0,
3005                                             &start, &end, EXTENT_DIRTY);
3006                 if (ret)
3007                         break;
3008                 clear_extent_dirty(&info->free_space_cache, start,
3009                                    end, GFP_NOFS);
3010         }
3011         return 0;
3012 }
3013
3014 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
3015                            struct btrfs_key *key)
3016 {
3017         int ret;
3018         struct btrfs_key found_key;
3019         struct extent_buffer *leaf;
3020         int slot;
3021
3022         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
3023         if (ret < 0)
3024                 return ret;
3025         while(1) {
3026                 slot = path->slots[0];
3027                 leaf = path->nodes[0];
3028                 if (slot >= btrfs_header_nritems(leaf)) {
3029                         ret = btrfs_next_leaf(root, path);
3030                         if (ret == 0)
3031                                 continue;
3032                         if (ret < 0)
3033                                 goto error;
3034                         break;
3035                 }
3036                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3037
3038                 if (found_key.objectid >= key->objectid &&
3039                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
3040                         return 0;
3041                 path->slots[0]++;
3042         }
3043         ret = -ENOENT;
3044 error:
3045         return ret;
3046 }
3047
3048 int btrfs_read_block_groups(struct btrfs_root *root)
3049 {
3050         struct btrfs_path *path;
3051         int ret;
3052         int bit;
3053         struct btrfs_block_group_cache *cache;
3054         struct btrfs_fs_info *info = root->fs_info;
3055         struct btrfs_space_info *space_info;
3056         struct extent_io_tree *block_group_cache;
3057         struct btrfs_key key;
3058         struct btrfs_key found_key;
3059         struct extent_buffer *leaf;
3060
3061         block_group_cache = &info->block_group_cache;
3062
3063         root = info->extent_root;
3064         key.objectid = 0;
3065         key.offset = 0;
3066         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3067         path = btrfs_alloc_path();
3068         if (!path)
3069                 return -ENOMEM;
3070
3071         while(1) {
3072                 ret = find_first_block_group(root, path, &key);
3073                 if (ret > 0) {
3074                         ret = 0;
3075                         goto error;
3076                 }
3077                 if (ret != 0) {
3078                         goto error;
3079                 }
3080                 leaf = path->nodes[0];
3081                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3082                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3083                 if (!cache) {
3084                         ret = -ENOMEM;
3085                         break;
3086                 }
3087
3088                 read_extent_buffer(leaf, &cache->item,
3089                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
3090                                    sizeof(cache->item));
3091                 memcpy(&cache->key, &found_key, sizeof(found_key));
3092                 cache->cached = 0;
3093                 cache->pinned = 0;
3094                 key.objectid = found_key.objectid + found_key.offset;
3095                 btrfs_release_path(root, path);
3096                 cache->flags = btrfs_block_group_flags(&cache->item);
3097                 bit = 0;
3098                 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
3099                         bit = BLOCK_GROUP_DATA;
3100                 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
3101                         bit = BLOCK_GROUP_SYSTEM;
3102                 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
3103                         bit = BLOCK_GROUP_METADATA;
3104                 }
3105                 set_avail_alloc_bits(info, cache->flags);
3106                 if (btrfs_chunk_readonly(root, cache->key.objectid))
3107                         cache->ro = 1;
3108
3109                 ret = update_space_info(info, cache->flags, found_key.offset,
3110                                         btrfs_block_group_used(&cache->item),
3111                                         &space_info);
3112                 BUG_ON(ret);
3113                 cache->space_info = space_info;
3114
3115                 /* use EXTENT_LOCKED to prevent merging */
3116                 set_extent_bits(block_group_cache, found_key.objectid,
3117                                 found_key.objectid + found_key.offset - 1,
3118                                 bit | EXTENT_LOCKED, GFP_NOFS);
3119                 set_state_private(block_group_cache, found_key.objectid,
3120                                   (unsigned long)cache);
3121         }
3122         ret = 0;
3123 error:
3124         btrfs_free_path(path);
3125         return ret;
3126 }
3127
3128 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
3129                            struct btrfs_root *root, u64 bytes_used,
3130                            u64 type, u64 chunk_objectid, u64 chunk_offset,
3131                            u64 size)
3132 {
3133         int ret;
3134         int bit = 0;
3135         struct btrfs_root *extent_root;
3136         struct btrfs_block_group_cache *cache;
3137         struct extent_io_tree *block_group_cache;
3138
3139         extent_root = root->fs_info->extent_root;
3140         block_group_cache = &root->fs_info->block_group_cache;
3141
3142         cache = kzalloc(sizeof(*cache), GFP_NOFS);
3143         BUG_ON(!cache);
3144         cache->key.objectid = chunk_offset;
3145         cache->key.offset = size;
3146
3147         btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3148         btrfs_set_block_group_used(&cache->item, bytes_used);
3149         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
3150         cache->flags = type;
3151         btrfs_set_block_group_flags(&cache->item, type);
3152
3153         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
3154                                 &cache->space_info);
3155         BUG_ON(ret);
3156
3157         bit = block_group_state_bits(type);
3158         set_extent_bits(block_group_cache, chunk_offset,
3159                         chunk_offset + size - 1,
3160                         bit | EXTENT_LOCKED, GFP_NOFS);
3161
3162         set_state_private(block_group_cache, chunk_offset,
3163                           (unsigned long)cache);
3164         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3165                                 sizeof(cache->item));
3166         BUG_ON(ret);
3167
3168         finish_current_insert(trans, extent_root);
3169         ret = del_pending_extents(trans, extent_root);
3170         BUG_ON(ret);
3171         set_avail_alloc_bits(extent_root->fs_info, type);
3172         return 0;
3173 }
3174
3175 /*
3176  * This is for converter use only.
3177  *
3178  * In that case, we don't know where are free blocks located.
3179  * Therefore all block group cache entries must be setup properly
3180  * before doing any block allocation.
3181  */
3182 int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
3183                             struct btrfs_root *root)
3184 {
3185         u64 total_bytes;
3186         u64 cur_start;
3187         u64 group_type;
3188         u64 group_size;
3189         u64 group_align;
3190         u64 total_data = 0;
3191         u64 total_metadata = 0;
3192         u64 chunk_objectid;
3193         int ret;
3194         int bit;
3195         struct btrfs_root *extent_root;
3196         struct btrfs_block_group_cache *cache;
3197         struct extent_io_tree *block_group_cache;
3198
3199         extent_root = root->fs_info->extent_root;
3200         block_group_cache = &root->fs_info->block_group_cache;
3201         chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3202         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
3203         group_align = 64 * root->sectorsize;
3204
3205         cur_start = 0;
3206         while (cur_start < total_bytes) {
3207                 group_size = total_bytes / 12;
3208                 group_size = min_t(u64, group_size, total_bytes - cur_start);
3209                 if (cur_start == 0) {
3210                         bit = BLOCK_GROUP_SYSTEM;
3211                         group_type = BTRFS_BLOCK_GROUP_SYSTEM;
3212                         group_size /= 4;
3213                         group_size &= ~(group_align - 1);
3214                         group_size = max_t(u64, group_size, 8 * 1024 * 1024);
3215                         group_size = min_t(u64, group_size, 32 * 1024 * 1024);
3216                 } else {
3217                         group_size &= ~(group_align - 1);
3218                         if (total_data >= total_metadata * 2) {
3219                                 group_type = BTRFS_BLOCK_GROUP_METADATA;
3220                                 group_size = min_t(u64, group_size,
3221                                                    1ULL * 1024 * 1024 * 1024);
3222                                 total_metadata += group_size;
3223                         } else {
3224                                 group_type = BTRFS_BLOCK_GROUP_DATA;
3225                                 group_size = min_t(u64, group_size,
3226                                                    5ULL * 1024 * 1024 * 1024);
3227                                 total_data += group_size;
3228                         }
3229                         if ((total_bytes - cur_start) * 4 < group_size * 5)
3230                                 group_size = total_bytes - cur_start;
3231                 }
3232
3233                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
3234                 BUG_ON(!cache);
3235
3236                 cache->key.objectid = cur_start;
3237                 cache->key.offset = group_size;
3238                 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
3239
3240                 btrfs_set_block_group_used(&cache->item, 0);
3241                 btrfs_set_block_group_chunk_objectid(&cache->item,
3242                                                      chunk_objectid);
3243                 btrfs_set_block_group_flags(&cache->item, group_type);
3244
3245                 cache->flags = group_type;
3246
3247                 ret = update_space_info(root->fs_info, group_type, group_size,
3248                                         0, &cache->space_info);
3249                 BUG_ON(ret);
3250                 set_avail_alloc_bits(extent_root->fs_info, group_type);
3251
3252                 set_extent_bits(block_group_cache, cur_start,
3253                                 cur_start + group_size - 1,
3254                                 bit | EXTENT_LOCKED, GFP_NOFS);
3255                 set_state_private(block_group_cache, cur_start,
3256                                   (unsigned long)cache);
3257                 cur_start += group_size;
3258         }
3259         /* then insert all the items */
3260         cur_start = 0;
3261         while(cur_start < total_bytes) {
3262                 cache = btrfs_lookup_block_group(root->fs_info, cur_start);
3263                 BUG_ON(!cache);
3264
3265                 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
3266                                         sizeof(cache->item));
3267                 BUG_ON(ret);
3268
3269                 finish_current_insert(trans, extent_root);
3270                 ret = del_pending_extents(trans, extent_root);
3271                 BUG_ON(ret);
3272
3273                 cur_start = cache->key.objectid + cache->key.offset;
3274         }
3275         return 0;
3276 }
3277
3278 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
3279                              struct btrfs_root *root,
3280                              u64 bytenr, u64 num_bytes, int alloc,
3281                              int mark_free)
3282 {
3283         return update_block_group(trans, root, bytenr, num_bytes,
3284                                   alloc, mark_free);
3285 }