git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/extent-tree.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "print-tree.h"
   5 #include "transaction.h"
   6
   7 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
   8                             *orig_root, u64 num_blocks, u64 search_start, u64
   9                             search_end, struct btrfs_key *ins);
  10 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
  11                                  btrfs_root *extent_root);
  12 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
  13                                btrfs_root *extent_root);
  14
  15 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
  16                                                  struct btrfs_block_group_cache
  17                                                  *hint, int data)
  18 {
  19         struct btrfs_block_group_cache *cache[8];
  20         struct btrfs_block_group_cache *found_group = NULL;
  21         struct btrfs_fs_info *info = root->fs_info;
  22         u64 used;
  23         u64 last = 0;
  24         u64 hint_last;
  25         int i;
  26         int ret;
  27         int full_search = 0;
  28         if (hint) {
  29                 used = btrfs_block_group_used(&hint->item);
  30                 if (used < (hint->key.offset * 2) / 3) {
  31                         return hint;
  32                 }
  33                 radix_tree_tag_clear(&info->block_group_radix,
  34                                      hint->key.objectid + hint->key.offset - 1,
  35                                      BTRFS_BLOCK_GROUP_AVAIL);
  36                 last = hint->key.objectid + hint->key.offset;
  37                 hint_last = last;
  38         } else {
  39                 hint_last = 0;
  40                 last = 0;
  41         }
  42         while(1) {
  43                 ret = radix_tree_gang_lookup_tag(&info->block_group_radix,
  44                                                  (void **)cache,
  45                                                  last, ARRAY_SIZE(cache),
  46                                                  BTRFS_BLOCK_GROUP_AVAIL);
  47                 if (!ret)
  48                         break;
  49                 for (i = 0; i < ret; i++) {
  50                         used = btrfs_block_group_used(&cache[i]->item);
  51                         if (used < (cache[i]->key.offset * 2) / 3) {
  52                                 info->block_group_cache = cache[i];
  53                                 found_group = cache[i];
  54                                 goto found;
  55                         }
  56                         radix_tree_tag_clear(&info->block_group_radix,
  57                                            cache[i]->key.objectid +
  58                                            cache[i]->key.offset - 1,
  59                                            BTRFS_BLOCK_GROUP_AVAIL);
  60                         last = cache[i]->key.objectid +
  61                                 cache[i]->key.offset;
  62                 }
  63         }
  64         last = hint_last;
  65 again:
  66         while(1) {
  67                 ret = radix_tree_gang_lookup(&info->block_group_radix,
  68                                                  (void **)cache,
  69                                                  last, ARRAY_SIZE(cache));
  70                 if (!ret)
  71                         break;
  72                 for (i = 0; i < ret; i++) {
  73                         used = btrfs_block_group_used(&cache[i]->item);
  74                         if (used < cache[i]->key.offset) {
  75                                 info->block_group_cache = cache[i];
  76                                 found_group = cache[i];
  77                                 goto found;
  78                         }
  79                         radix_tree_tag_clear(&info->block_group_radix,
  80                                            cache[i]->key.objectid +
  81                                            cache[i]->key.offset - 1,
  82                                            BTRFS_BLOCK_GROUP_AVAIL);
  83                         last = cache[i]->key.objectid +
  84                                 cache[i]->key.offset;
  85                 }
  86         }
  87         info->block_group_cache = NULL;
  88         if (!full_search) {
  89                 last = 0;
  90                 full_search = 1;
  91                 goto again;
  92         }
  93 found:
  94         if (!found_group) {
  95                 ret = radix_tree_gang_lookup(&info->block_group_radix,
  96                                              (void **)&found_group, 0, 1);
  97                 BUG_ON(ret != 1);
  98         }
  99         return found_group;
 100 }
 101
 102 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 103                                 struct btrfs_root *root,
 104                                 u64 blocknr, u64 num_blocks)
 105 {
 106         struct btrfs_path *path;
 107         int ret;
 108         struct btrfs_key key;
 109         struct btrfs_leaf *l;
 110         struct btrfs_extent_item *item;
 111         struct btrfs_key ins;
 112         u32 refs;
 113
 114         find_free_extent(trans, root->fs_info->extent_root, 0, 0, (u64)-1,
 115                          &ins);
 116         path = btrfs_alloc_path();
 117         BUG_ON(!path);
 118         btrfs_init_path(path);
 119         key.objectid = blocknr;
 120         key.flags = 0;
 121         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 122         key.offset = num_blocks;
 123         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 124                                 0, 1);
 125         if (ret != 0) {
 126 printk("can't find block %Lu %Lu\n", blocknr, num_blocks);
 127                 BUG();
 128         }
 129         BUG_ON(ret != 0);
 130         l = btrfs_buffer_leaf(path->nodes[0]);
 131         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 132         refs = btrfs_extent_refs(item);
 133         btrfs_set_extent_refs(item, refs + 1);
 134         btrfs_mark_buffer_dirty(path->nodes[0]);
 135
 136         btrfs_release_path(root->fs_info->extent_root, path);
 137         btrfs_free_path(path);
 138         finish_current_insert(trans, root->fs_info->extent_root);
 139         del_pending_extents(trans, root->fs_info->extent_root);
 140         return 0;
 141 }
 142
 143 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
 144                              struct btrfs_root *root, u64 blocknr,
 145                              u64 num_blocks, u32 *refs)
 146 {
 147         struct btrfs_path *path;
 148         int ret;
 149         struct btrfs_key key;
 150         struct btrfs_leaf *l;
 151         struct btrfs_extent_item *item;
 152
 153         path = btrfs_alloc_path();
 154         btrfs_init_path(path);
 155         key.objectid = blocknr;
 156         key.offset = num_blocks;
 157         key.flags = 0;
 158         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 159         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
 160                                 0, 0);
 161         if (ret != 0)
 162                 BUG();
 163         l = btrfs_buffer_leaf(path->nodes[0]);
 164         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
 165         *refs = btrfs_extent_refs(item);
 166         btrfs_release_path(root->fs_info->extent_root, path);
 167         btrfs_free_path(path);
 168         return 0;
 169 }
 170
 171 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
 172                        struct btrfs_root *root)
 173 {
 174         return btrfs_inc_extent_ref(trans, root, bh_blocknr(root->node), 1);
 175 }
 176
 177 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 178                   struct buffer_head *buf)
 179 {
 180         u64 blocknr;
 181         struct btrfs_node *buf_node;
 182         struct btrfs_leaf *buf_leaf;
 183         struct btrfs_disk_key *key;
 184         struct btrfs_file_extent_item *fi;
 185         int i;
 186         int leaf;
 187         int ret;
 188
 189         if (!root->ref_cows)
 190                 return 0;
 191         buf_node = btrfs_buffer_node(buf);
 192         leaf = btrfs_is_leaf(buf_node);
 193         buf_leaf = btrfs_buffer_leaf(buf);
 194         for (i = 0; i < btrfs_header_nritems(&buf_node->header); i++) {
 195                 if (leaf) {
 196                         key = &buf_leaf->items[i].key;
 197                         if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
 198                                 continue;
 199                         fi = btrfs_item_ptr(buf_leaf, i,
 200                                             struct btrfs_file_extent_item);
 201                         if (btrfs_file_extent_type(fi) ==
 202                             BTRFS_FILE_EXTENT_INLINE)
 203                                 continue;
 204                         ret = btrfs_inc_extent_ref(trans, root,
 205                                     btrfs_file_extent_disk_blocknr(fi),
 206                                     btrfs_file_extent_disk_num_blocks(fi));
 207                         BUG_ON(ret);
 208                 } else {
 209                         blocknr = btrfs_node_blockptr(buf_node, i);
 210                         ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
 211                         BUG_ON(ret);
 212                 }
 213         }
 214         return 0;
 215 }
 216
 217 static int write_one_cache_group(struct btrfs_trans_handle *trans,
 218                                  struct btrfs_root *root,
 219                                  struct btrfs_path *path,
 220                                  struct btrfs_block_group_cache *cache)
 221 {
 222         int ret;
 223         int pending_ret;
 224         struct btrfs_root *extent_root = root->fs_info->extent_root;
 225         struct btrfs_block_group_item *bi;
 226         struct btrfs_key ins;
 227
 228         find_free_extent(trans, extent_root, 0, 0, (u64)-1, &ins);
 229         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
 230         BUG_ON(ret);
 231         bi = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 232                             struct btrfs_block_group_item);
 233         memcpy(bi, &cache->item, sizeof(*bi));
 234         mark_buffer_dirty(path->nodes[0]);
 235         btrfs_release_path(extent_root, path);
 236
 237         finish_current_insert(trans, extent_root);
 238         pending_ret = del_pending_extents(trans, extent_root);
 239         if (ret)
 240                 return ret;
 241         if (pending_ret)
 242                 return pending_ret;
 243         return 0;
 244
 245 }
 246
 247 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 248                                     struct btrfs_root *root)
 249 {
 250         struct btrfs_block_group_cache *cache[8];
 251         int ret;
 252         int err = 0;
 253         int werr = 0;
 254         struct radix_tree_root *radix = &root->fs_info->block_group_radix;
 255         int i;
 256         struct btrfs_path *path;
 257
 258         path = btrfs_alloc_path();
 259         if (!path)
 260                 return -ENOMEM;
 261
 262         while(1) {
 263                 ret = radix_tree_gang_lookup_tag(radix, (void **)cache,
 264                                                  0, ARRAY_SIZE(cache),
 265                                                  BTRFS_BLOCK_GROUP_DIRTY);
 266                 if (!ret)
 267                         break;
 268                 for (i = 0; i < ret; i++) {
 269                         radix_tree_tag_clear(radix, cache[i]->key.objectid +
 270                                              cache[i]->key.offset - 1,
 271                                              BTRFS_BLOCK_GROUP_DIRTY);
 272                         err = write_one_cache_group(trans, root,
 273                                                     path, cache[i]);
 274                         if (err)
 275                                 werr = err;
 276                         cache[i]->last_alloc = cache[i]->first_free;
 277                 }
 278         }
 279         btrfs_free_path(path);
 280         return werr;
 281 }
 282
 283 static int update_block_group(struct btrfs_trans_handle *trans,
 284                               struct btrfs_root *root,
 285                               u64 blocknr, u64 num, int alloc)
 286 {
 287         struct btrfs_block_group_cache *cache;
 288         struct btrfs_fs_info *info = root->fs_info;
 289         u64 total = num;
 290         u64 old_val;
 291         u64 block_in_group;
 292         int ret;
 293         while(total) {
 294                 ret = radix_tree_gang_lookup(&info->block_group_radix,
 295                                              (void **)&cache, blocknr, 1);
 296                 if (!ret) {
 297                         printk(KERN_CRIT "blocknr %Lu lookup failed\n",
 298                                blocknr);
 299                         return -1;
 300                 }
 301                 block_in_group = blocknr - cache->key.objectid;
 302                 WARN_ON(block_in_group > cache->key.offset);
 303                 radix_tree_tag_set(&info->block_group_radix,
 304                                    cache->key.objectid + cache->key.offset - 1,
 305                                    BTRFS_BLOCK_GROUP_DIRTY);
 306
 307                 old_val = btrfs_block_group_used(&cache->item);
 308                 num = min(total, cache->key.offset - block_in_group);
 309                 total -= num;
 310                 blocknr += num;
 311                 if (alloc) {
 312                         old_val += num;
 313                         if (blocknr > cache->last_alloc)
 314                                 cache->last_alloc = blocknr;
 315                 } else {
 316                         old_val -= num;
 317                         if (blocknr < cache->first_free)
 318                                 cache->first_free = blocknr;
 319                 }
 320                 btrfs_set_block_group_used(&cache->item, old_val);
 321         }
 322         return 0;
 323 }
 324
 325 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
 326                                btrfs_root *root)
 327 {
 328         unsigned long gang[8];
 329         u64 first = 0;
 330         int ret;
 331         int i;
 332         struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
 333
 334         while(1) {
 335                 ret = find_first_radix_bit(pinned_radix, gang,
 336                                            ARRAY_SIZE(gang));
 337                 if (!ret)
 338                         break;
 339                 if (!first)
 340                         first = gang[0];
 341                 for (i = 0; i < ret; i++) {
 342                         clear_radix_bit(pinned_radix, gang[i]);
 343                 }
 344         }
 345         return 0;
 346 }
 347
 348 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
 349                                  btrfs_root *extent_root)
 350 {
 351         struct btrfs_key ins;
 352         struct btrfs_extent_item extent_item;
 353         int i;
 354         int ret;
 355         u64 super_blocks_used;
 356         struct btrfs_fs_info *info = extent_root->fs_info;
 357
 358         btrfs_set_extent_refs(&extent_item, 1);
 359         ins.offset = 1;
 360         ins.flags = 0;
 361         btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
 362         btrfs_set_extent_owner(&extent_item, extent_root->root_key.objectid);
 363
 364         for (i = 0; i < extent_root->fs_info->extent_tree_insert_nr; i++) {
 365                 ins.objectid = extent_root->fs_info->extent_tree_insert[i];
 366                 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
 367                 btrfs_set_super_blocks_used(info->disk_super,
 368                                             super_blocks_used + 1);
 369                 ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
 370                                         sizeof(extent_item));
 371                 BUG_ON(ret);
 372         }
 373         extent_root->fs_info->extent_tree_insert_nr = 0;
 374         extent_root->fs_info->extent_tree_prealloc_nr = 0;
 375         return 0;
 376 }
 377
 378 static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
 379 {
 380         int err;
 381         struct btrfs_header *header;
 382         struct buffer_head *bh;
 383
 384         if (!pending) {
 385                 bh = btrfs_find_tree_block(root, blocknr);
 386                 if (bh) {
 387                         if (buffer_uptodate(bh)) {
 388                                 u64 transid =
 389                                     root->fs_info->running_transaction->transid;
 390                                 header = btrfs_buffer_header(bh);
 391                                 if (btrfs_header_generation(header) ==
 392                                     transid) {
 393                                         btrfs_block_release(root, bh);
 394                                         return 0;
 395                                 }
 396                         }
 397                         btrfs_block_release(root, bh);
 398                 }
 399                 err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
 400         } else {
 401                 err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
 402         }
 403         BUG_ON(err);
 404         return 0;
 405 }
 406
 407 /*
 408  * remove an extent from the root, returns 0 on success
 409  */
 410 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 411                          *root, u64 blocknr, u64 num_blocks, int pin)
 412 {
 413         struct btrfs_path *path;
 414         struct btrfs_key key;
 415         struct btrfs_fs_info *info = root->fs_info;
 416         struct btrfs_root *extent_root = info->extent_root;
 417         int ret;
 418         struct btrfs_extent_item *ei;
 419         struct btrfs_key ins;
 420         u32 refs;
 421
 422         key.objectid = blocknr;
 423         key.flags = 0;
 424         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 425         key.offset = num_blocks;
 426
 427         find_free_extent(trans, root, 0, 0, (u64)-1, &ins);
 428         path = btrfs_alloc_path();
 429         BUG_ON(!path);
 430         btrfs_init_path(path);
 431
 432         ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
 433         if (ret) {
 434                 printk("failed to find %Lu\n", key.objectid);
 435                 btrfs_print_tree(extent_root, extent_root->node);
 436                 printk("failed to find %Lu\n", key.objectid);
 437                 BUG();
 438         }
 439         ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 440                             struct btrfs_extent_item);
 441         BUG_ON(ei->refs == 0);
 442         refs = btrfs_extent_refs(ei) - 1;
 443         btrfs_set_extent_refs(ei, refs);
 444         btrfs_mark_buffer_dirty(path->nodes[0]);
 445         if (refs == 0) {
 446                 u64 super_blocks_used;
 447
 448                 if (pin) {
 449                         ret = pin_down_block(root, blocknr, 0);
 450                         BUG_ON(ret);
 451                 }
 452
 453                 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
 454                 btrfs_set_super_blocks_used(info->disk_super,
 455                                             super_blocks_used - num_blocks);
 456                 ret = btrfs_del_item(trans, extent_root, path);
 457                 if (ret)
 458                         BUG();
 459                 ret = update_block_group(trans, root, blocknr, num_blocks, 0);
 460                 BUG_ON(ret);
 461         }
 462         btrfs_release_path(extent_root, path);
 463         btrfs_free_path(path);
 464         finish_current_insert(trans, extent_root);
 465         return ret;
 466 }
 467
 468 /*
 469  * find all the blocks marked as pending in the radix tree and remove
 470  * them from the extent map
 471  */
 472 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
 473                                btrfs_root *extent_root)
 474 {
 475         int ret;
 476         int wret;
 477         int err = 0;
 478         unsigned long gang[4];
 479         int i;
 480         struct radix_tree_root *pending_radix;
 481         struct radix_tree_root *pinned_radix;
 482
 483         pending_radix = &extent_root->fs_info->pending_del_radix;
 484         pinned_radix = &extent_root->fs_info->pinned_radix;
 485
 486         while(1) {
 487                 ret = find_first_radix_bit(pending_radix, gang,
 488                                            ARRAY_SIZE(gang));
 489                 if (!ret)
 490                         break;
 491                 for (i = 0; i < ret; i++) {
 492                         wret = set_radix_bit(pinned_radix, gang[i]);
 493                         BUG_ON(wret);
 494                         wret = clear_radix_bit(pending_radix, gang[i]);
 495                         BUG_ON(wret);
 496                         wret = __free_extent(trans, extent_root,
 497                                              gang[i], 1, 0);
 498                         if (wret)
 499                                 err = wret;
 500                 }
 501         }
 502         return err;
 503 }
 504
 505 /*
 506  * remove an extent from the root, returns 0 on success
 507  */
 508 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 509                       *root, u64 blocknr, u64 num_blocks, int pin)
 510 {
 511         struct btrfs_root *extent_root = root->fs_info->extent_root;
 512         int pending_ret;
 513         int ret;
 514
 515         if (root == extent_root) {
 516                 pin_down_block(root, blocknr, 1);
 517                 return 0;
 518         }
 519         ret = __free_extent(trans, root, blocknr, num_blocks, pin);
 520         pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
 521         return ret ? ret : pending_ret;
 522 }
 523
 524 /*
 525  * walks the btree of allocated extents and find a hole of a given size.
 526  * The key ins is changed to record the hole:
 527  * ins->objectid == block start
 528  * ins->flags = BTRFS_EXTENT_ITEM_KEY
 529  * ins->offset == number of blocks
 530  * Any available blocks before search_start are skipped.
 531  */
 532 static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 533                             *orig_root, u64 num_blocks, u64 search_start, u64
 534                             search_end, struct btrfs_key *ins)
 535 {
 536         struct btrfs_path *path;
 537         struct btrfs_key key;
 538         int ret;
 539         u64 hole_size = 0;
 540         int slot = 0;
 541         u64 last_block = 0;
 542         u64 test_block;
 543         int start_found;
 544         struct btrfs_leaf *l;
 545         struct btrfs_root * root = orig_root->fs_info->extent_root;
 546         struct btrfs_fs_info *info = root->fs_info;
 547         int total_needed = num_blocks;
 548         int total_found = 0;
 549         int fill_prealloc = 0;
 550         int level;
 551         int update_block_group = 0;
 552         struct btrfs_block_group_cache *hint_block_group;
 553
 554         path = btrfs_alloc_path();
 555         ins->flags = 0;
 556         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
 557
 558         level = btrfs_header_level(btrfs_buffer_header(root->node));
 559         /* find search start here */
 560         if (0 && search_start && num_blocks) {
 561                 u64 used;
 562                 ret = radix_tree_gang_lookup(&info->block_group_radix,
 563                                              (void **)&hint_block_group,
 564                                              search_start, 1);
 565                 if (ret) {
 566                         used = btrfs_block_group_used(&hint_block_group->item);
 567                         if (used > (hint_block_group->key.offset * 9) / 10)
 568                                 search_start = 0;
 569                         else if (search_start < hint_block_group->last_alloc)
 570                                 search_start = hint_block_group->last_alloc;
 571                 } else {
 572                         search_start = 0;
 573                 }
 574         }
 575         if (num_blocks == 0) {
 576                 fill_prealloc = 1;
 577                 num_blocks = 1;
 578                 total_needed = (min(level + 1, BTRFS_MAX_LEVEL) + 2) * 3;
 579         }
 580         if (1 || !search_start) {
 581                 trans->block_group = btrfs_find_block_group(root,
 582                                                             trans->block_group,
 583                                                             0);
 584                 if (trans->block_group->last_alloc > search_start)
 585                         search_start = trans->block_group->last_alloc;
 586                 update_block_group = 1;
 587         }
 588 check_failed:
 589         btrfs_init_path(path);
 590         ins->objectid = search_start;
 591         ins->offset = 0;
 592         start_found = 0;
 593         ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
 594         if (ret < 0)
 595                 goto error;
 596
 597         if (path->slots[0] > 0)
 598                 path->slots[0]--;
 599
 600         while (1) {
 601                 l = btrfs_buffer_leaf(path->nodes[0]);
 602                 slot = path->slots[0];
 603                 if (slot >= btrfs_header_nritems(&l->header)) {
 604                         if (fill_prealloc) {
 605                                 info->extent_tree_prealloc_nr = 0;
 606                                 total_found = 0;
 607                         }
 608                         ret = btrfs_next_leaf(root, path);
 609                         if (ret == 0)
 610                                 continue;
 611                         if (ret < 0)
 612                                 goto error;
 613                         if (!start_found) {
 614                                 ins->objectid = search_start;
 615                                 ins->offset = (u64)-1 - search_start;
 616                                 start_found = 1;
 617                                 goto check_pending;
 618                         }
 619                         ins->objectid = last_block > search_start ?
 620                                         last_block : search_start;
 621                         ins->offset = (u64)-1 - ins->objectid;
 622                         goto check_pending;
 623                 }
 624                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
 625                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
 626                         goto next;
 627                 if (key.objectid >= search_start) {
 628                         if (start_found) {
 629                                 if (last_block < search_start)
 630                                         last_block = search_start;
 631                                 hole_size = key.objectid - last_block;
 632                                 if (hole_size >= num_blocks) {
 633                                         ins->objectid = last_block;
 634                                         ins->offset = hole_size;
 635                                         goto check_pending;
 636                                 }
 637                         }
 638                 }
 639                 start_found = 1;
 640                 last_block = key.objectid + key.offset;
 641 next:
 642                 path->slots[0]++;
 643         }
 644         // FIXME -ENOSPC
 645 check_pending:
 646         /* we have to make sure we didn't find an extent that has already
 647          * been allocated by the map tree or the original allocation
 648          */
 649         btrfs_release_path(root, path);
 650         BUG_ON(ins->objectid < search_start);
 651         if (ins->objectid >= btrfs_super_total_blocks(info->disk_super)) {
 652                 if (search_start == 0)
 653                         return -ENOSPC;
 654                 search_start = 0;
 655                 goto check_failed;
 656         }
 657         for (test_block = ins->objectid;
 658              test_block < ins->objectid + num_blocks; test_block++) {
 659                 if (test_radix_bit(&info->pinned_radix, test_block)) {
 660                         search_start = test_block + 1;
 661                         goto check_failed;
 662                 }
 663         }
 664         if (!fill_prealloc && info->extent_tree_insert_nr) {
 665                 u64 last =
 666                   info->extent_tree_insert[info->extent_tree_insert_nr - 1];
 667                 if (ins->objectid + num_blocks >
 668                     info->extent_tree_insert[0] &&
 669                     ins->objectid <= last) {
 670                         search_start = last + 1;
 671                         WARN_ON(1);
 672                         goto check_failed;
 673                 }
 674         }
 675         if (!fill_prealloc && info->extent_tree_prealloc_nr) {
 676                 u64 first =
 677                   info->extent_tree_prealloc[info->extent_tree_prealloc_nr - 1];
 678                 if (ins->objectid + num_blocks > first &&
 679                     ins->objectid <= info->extent_tree_prealloc[0]) {
 680                         search_start = info->extent_tree_prealloc[0] + 1;
 681                         WARN_ON(1);
 682                         goto check_failed;
 683                 }
 684         }
 685         if (fill_prealloc) {
 686                 int nr;
 687                 test_block = ins->objectid;
 688                 while(test_block < ins->objectid + ins->offset &&
 689                       total_found < total_needed) {
 690                         nr = total_needed - total_found - 1;
 691                         BUG_ON(nr < 0);
 692                         info->extent_tree_prealloc[nr] = test_block;
 693                         total_found++;
 694                         test_block++;
 695                 }
 696                 if (total_found < total_needed) {
 697                         search_start = test_block;
 698                         goto check_failed;
 699                 }
 700                 info->extent_tree_prealloc_nr = total_found;
 701         }
 702         if (update_block_group) {
 703                 ret = radix_tree_gang_lookup(&info->block_group_radix,
 704                                              (void **)&trans->block_group,
 705                                              ins->objectid, 1);
 706                 if (ret) {
 707                         trans->block_group->last_alloc = ins->objectid;
 708                 }
 709         }
 710         ins->offset = num_blocks;
 711         btrfs_free_path(path);
 712         return 0;
 713 error:
 714         btrfs_release_path(root, path);
 715         btrfs_free_path(path);
 716         return ret;
 717 }
 718 /*
 719  * finds a free extent and does all the dirty work required for allocation
 720  * returns the key for the extent through ins, and a tree buffer for
 721  * the first block of the extent through buf.
 722  *
 723  * returns 0 if everything worked, non-zero otherwise.
 724  */
 725 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 726                        struct btrfs_root *root, u64 owner,
 727                        u64 num_blocks, u64 search_start,
 728                        u64 search_end, struct btrfs_key *ins)
 729 {
 730         int ret;
 731         int pending_ret;
 732         u64 super_blocks_used;
 733         struct btrfs_fs_info *info = root->fs_info;
 734         struct btrfs_root *extent_root = info->extent_root;
 735         struct btrfs_extent_item extent_item;
 736         struct btrfs_key prealloc_key;
 737
 738         btrfs_set_extent_refs(&extent_item, 1);
 739         btrfs_set_extent_owner(&extent_item, owner);
 740
 741         if (root == extent_root) {
 742                 int nr;
 743                 BUG_ON(info->extent_tree_prealloc_nr == 0);
 744                 BUG_ON(num_blocks != 1);
 745                 ins->offset = 1;
 746                 info->extent_tree_prealloc_nr--;
 747                 nr = info->extent_tree_prealloc_nr;
 748                 ins->objectid = info->extent_tree_prealloc[nr];
 749                 info->extent_tree_insert[info->extent_tree_insert_nr++] =
 750                         ins->objectid;
 751                 ret = update_block_group(trans, root,
 752                                          ins->objectid, ins->offset, 1);
 753                 BUG_ON(ret);
 754                 return 0;
 755         }
 756         /* do the real allocation */
 757         ret = find_free_extent(trans, root, num_blocks, search_start,
 758                                search_end, ins);
 759         if (ret)
 760                 return ret;
 761
 762         /* then do prealloc for the extent tree */
 763         ret = find_free_extent(trans, root, 0, ins->objectid + ins->offset,
 764                                search_end, &prealloc_key);
 765         if (ret)
 766                 return ret;
 767
 768         super_blocks_used = btrfs_super_blocks_used(info->disk_super);
 769         btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
 770                                     num_blocks);
 771         ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
 772                                 sizeof(extent_item));
 773
 774         finish_current_insert(trans, extent_root);
 775         pending_ret = del_pending_extents(trans, extent_root);
 776         if (ret)
 777                 return ret;
 778         if (pending_ret)
 779                 return pending_ret;
 780         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
 781         return 0;
 782 }
 783
 784 /*
 785  * helper function to allocate a block for a given tree
 786  * returns the tree buffer or NULL.
 787  */
 788 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 789                                            struct btrfs_root *root, u64 hint)
 790 {
 791         struct btrfs_key ins;
 792         int ret;
 793         struct buffer_head *buf;
 794
 795         ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
 796                                  1, hint, (unsigned long)-1, &ins);
 797         if (ret) {
 798                 BUG();
 799                 return NULL;
 800         }
 801         BUG_ON(ret);
 802         buf = btrfs_find_create_tree_block(root, ins.objectid);
 803         set_buffer_uptodate(buf);
 804         set_buffer_checked(buf);
 805         set_radix_bit(&trans->transaction->dirty_pages, buf->b_page->index);
 806         return buf;
 807 }
 808
 809 static int drop_leaf_ref(struct btrfs_trans_handle *trans,
 810                          struct btrfs_root *root, struct buffer_head *cur)
 811 {
 812         struct btrfs_disk_key *key;
 813         struct btrfs_leaf *leaf;
 814         struct btrfs_file_extent_item *fi;
 815         int i;
 816         int nritems;
 817         int ret;
 818
 819         BUG_ON(!btrfs_is_leaf(btrfs_buffer_node(cur)));
 820         leaf = btrfs_buffer_leaf(cur);
 821         nritems = btrfs_header_nritems(&leaf->header);
 822         for (i = 0; i < nritems; i++) {
 823                 key = &leaf->items[i].key;
 824                 if (btrfs_disk_key_type(key) != BTRFS_EXTENT_DATA_KEY)
 825                         continue;
 826                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
 827                 if (btrfs_file_extent_type(fi) == BTRFS_FILE_EXTENT_INLINE)
 828                         continue;
 829                 /*
 830                  * FIXME make sure to insert a trans record that
 831                  * repeats the snapshot del on crash
 832                  */
 833                 ret = btrfs_free_extent(trans, root,
 834                                         btrfs_file_extent_disk_blocknr(fi),
 835                                         btrfs_file_extent_disk_num_blocks(fi),
 836                                         0);
 837                 BUG_ON(ret);
 838         }
 839         return 0;
 840 }
 841
 842 /*
 843  * helper function for drop_snapshot, this walks down the tree dropping ref
 844  * counts as it goes.
 845  */
 846 static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
 847                           *root, struct btrfs_path *path, int *level)
 848 {
 849         struct buffer_head *next;
 850         struct buffer_head *cur;
 851         u64 blocknr;
 852         int ret;
 853         u32 refs;
 854
 855         WARN_ON(*level < 0);
 856         WARN_ON(*level >= BTRFS_MAX_LEVEL);
 857         ret = lookup_extent_ref(trans, root, bh_blocknr(path->nodes[*level]),
 858                                1, &refs);
 859         BUG_ON(ret);
 860         if (refs > 1)
 861                 goto out;
 862         /*
 863          * walk down to the last node level and free all the leaves
 864          */
 865         while(*level >= 0) {
 866                 WARN_ON(*level < 0);
 867                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
 868                 cur = path->nodes[*level];
 869                 if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
 870                         WARN_ON(1);
 871                 if (path->slots[*level] >=
 872                     btrfs_header_nritems(btrfs_buffer_header(cur)))
 873                         break;
 874                 if (*level == 0) {
 875                         ret = drop_leaf_ref(trans, root, cur);
 876                         BUG_ON(ret);
 877                         break;
 878                 }
 879                 blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
 880                                               path->slots[*level]);
 881                 ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
 882                 BUG_ON(ret);
 883                 if (refs != 1) {
 884                         path->slots[*level]++;
 885                         ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
 886                         BUG_ON(ret);
 887                         continue;
 888                 }
 889                 next = read_tree_block(root, blocknr);
 890                 WARN_ON(*level <= 0);
 891                 if (path->nodes[*level-1])
 892                         btrfs_block_release(root, path->nodes[*level-1]);
 893                 path->nodes[*level-1] = next;
 894                 *level = btrfs_header_level(btrfs_buffer_header(next));
 895                 path->slots[*level] = 0;
 896         }
 897 out:
 898         WARN_ON(*level < 0);
 899         WARN_ON(*level >= BTRFS_MAX_LEVEL);
 900         ret = btrfs_free_extent(trans, root,
 901                                 bh_blocknr(path->nodes[*level]), 1, 1);
 902         btrfs_block_release(root, path->nodes[*level]);
 903         path->nodes[*level] = NULL;
 904         *level += 1;
 905         BUG_ON(ret);
 906         return 0;
 907 }
 908
 909 /*
 910  * helper for dropping snapshots.  This walks back up the tree in the path
 911  * to find the first node higher up where we haven't yet gone through
 912  * all the slots
 913  */
 914 static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
 915                         *root, struct btrfs_path *path, int *level)
 916 {
 917         int i;
 918         int slot;
 919         int ret;
 920         for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
 921                 slot = path->slots[i];
 922                 if (slot < btrfs_header_nritems(
 923                     btrfs_buffer_header(path->nodes[i])) - 1) {
 924                         path->slots[i]++;
 925                         *level = i;
 926                         return 0;
 927                 } else {
 928                         ret = btrfs_free_extent(trans, root,
 929                                                 bh_blocknr(path->nodes[*level]),
 930                                                 1, 1);
 931                         BUG_ON(ret);
 932                         btrfs_block_release(root, path->nodes[*level]);
 933                         path->nodes[*level] = NULL;
 934                         *level = i + 1;
 935                 }
 936         }
 937         return 1;
 938 }
 939
 940 /*
 941  * drop the reference count on the tree rooted at 'snap'.  This traverses
 942  * the tree freeing any blocks that have a ref count of zero after being
 943  * decremented.
 944  */
 945 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
 946                         *root, struct buffer_head *snap)
 947 {
 948         int ret = 0;
 949         int wret;
 950         int level;
 951         struct btrfs_path *path;
 952         int i;
 953         int orig_level;
 954
 955         path = btrfs_alloc_path();
 956         BUG_ON(!path);
 957         btrfs_init_path(path);
 958
 959         level = btrfs_header_level(btrfs_buffer_header(snap));
 960         orig_level = level;
 961         path->nodes[level] = snap;
 962         path->slots[level] = 0;
 963         while(1) {
 964                 wret = walk_down_tree(trans, root, path, &level);
 965                 if (wret > 0)
 966                         break;
 967                 if (wret < 0)
 968                         ret = wret;
 969
 970                 wret = walk_up_tree(trans, root, path, &level);
 971                 if (wret > 0)
 972                         break;
 973                 if (wret < 0)
 974                         ret = wret;
 975                 btrfs_btree_balance_dirty(root);
 976         }
 977         for (i = 0; i <= orig_level; i++) {
 978                 if (path->nodes[i]) {
 979                         btrfs_block_release(root, path->nodes[i]);
 980                 }
 981         }
 982         btrfs_free_path(path);
 983         return ret;
 984 }
 985
 986 int btrfs_free_block_groups(struct btrfs_fs_info *info)
 987 {
 988         int ret;
 989         struct btrfs_block_group_cache *cache[8];
 990         int i;
 991
 992         while(1) {
 993                 ret = radix_tree_gang_lookup(&info->block_group_radix,
 994                                              (void **)cache, 0,
 995                                              ARRAY_SIZE(cache));
 996                 if (!ret)
 997                         break;
 998                 for (i = 0; i < ret; i++) {
 999                         radix_tree_delete(&info->block_group_radix,
1000                                           cache[i]->key.objectid +
1001                                           cache[i]->key.offset - 1);
1002                         kfree(cache[i]);
1003                 }
1004         }
1005         return 0;
1006 }
1007
1008 int btrfs_read_block_groups(struct btrfs_root *root)
1009 {
1010         struct btrfs_path *path;
1011         int ret;
1012         int err = 0;
1013         struct btrfs_block_group_item *bi;
1014         struct btrfs_block_group_cache *cache;
1015         struct btrfs_key key;
1016         struct btrfs_key found_key;
1017         struct btrfs_leaf *leaf;
1018         u64 group_size_blocks = BTRFS_BLOCK_GROUP_SIZE / root->blocksize;
1019         u64 used;
1020
1021         root = root->fs_info->extent_root;
1022         key.objectid = 0;
1023         key.offset = group_size_blocks;
1024         key.flags = 0;
1025         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
1026
1027         path = btrfs_alloc_path();
1028         if (!path)
1029                 return -ENOMEM;
1030
1031         while(1) {
1032                 ret = btrfs_search_slot(NULL, root->fs_info->extent_root,
1033                                         &key, path, 0, 0);
1034                 if (ret != 0) {
1035                         err = ret;
1036                         break;
1037                 }
1038                 leaf = btrfs_buffer_leaf(path->nodes[0]);
1039                 btrfs_disk_key_to_cpu(&found_key,
1040                                       &leaf->items[path->slots[0]].key);
1041                 cache = kmalloc(sizeof(*cache), GFP_NOFS);
1042                 if (!cache) {
1043                         err = -1;
1044                         break;
1045                 }
1046                 bi = btrfs_item_ptr(leaf, path->slots[0],
1047                                     struct btrfs_block_group_item);
1048                 memcpy(&cache->item, bi, sizeof(*bi));
1049                 memcpy(&cache->key, &found_key, sizeof(found_key));
1050                 cache->last_alloc = cache->key.objectid;
1051                 cache->first_free = cache->key.objectid;
1052                 key.objectid = found_key.objectid + found_key.offset;
1053                 btrfs_release_path(root, path);
1054                 ret = radix_tree_insert(&root->fs_info->block_group_radix,
1055                                         found_key.objectid +
1056                                         found_key.offset - 1,
1057                                         (void *)cache);
1058                 BUG_ON(ret);
1059                 used = btrfs_block_group_used(bi);
1060                 if (used < (key.offset * 2) / 3) {
1061                         radix_tree_tag_set(&root->fs_info->block_group_radix,
1062                                            found_key.objectid +
1063                                            found_key.offset - 1,
1064                                            BTRFS_BLOCK_GROUP_AVAIL);
1065                 }
1066                 if (key.objectid >=
1067                     btrfs_super_total_blocks(root->fs_info->disk_super))
1068                         break;
1069         }
1070
1071         btrfs_free_path(path);
1072         return 0;
1073 }