git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/disk-io.c

   1 #include <linux/module.h>
   2 #include <linux/fs.h>
   3 #include <linux/blkdev.h>
   4 #include <linux/crypto.h>
   5 #include <linux/scatterlist.h>
   6 #include <linux/swap.h>
   7 #include <linux/radix-tree.h>
   8 #include "ctree.h"
   9 #include "disk-io.h"
  10 #include "transaction.h"
  11 #include "btrfs_inode.h"
  12
  13 struct dev_lookup {
  14         u64 block_start;
  15         u64 num_blocks;
  16         u64 device_id;
  17         struct block_device *bdev;
  18 };
  19
  20 int btrfs_insert_dev_radix(struct btrfs_root *root,
  21                            struct block_device *bdev,
  22                            u64 device_id,
  23                            u64 block_start,
  24                            u64 num_blocks)
  25 {
  26         struct dev_lookup *lookup;
  27         char b[BDEVNAME_SIZE];
  28         int ret;
  29
  30         lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
  31         if (!lookup)
  32                 return -ENOMEM;
  33         lookup->block_start = block_start;
  34         lookup->num_blocks = num_blocks;
  35         lookup->bdev = bdev;
  36         lookup->device_id = device_id;
  37 printk("inserting %s into dev radix %Lu %Lu\n", bdevname(bdev, b), block_start, num_blocks);
  38
  39         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  40                                 num_blocks - 1, lookup);
  41         return ret;
  42 }
  43
  44 u64 bh_blocknr(struct buffer_head *bh)
  45 {
  46         int blkbits = bh->b_page->mapping->host->i_blkbits;
  47         u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
  48         unsigned long offset;
  49
  50         if (PageHighMem(bh->b_page))
  51                 offset = (unsigned long)bh->b_data;
  52         else
  53                 offset = bh->b_data - (char *)page_address(bh->b_page);
  54         blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
  55         return blocknr;
  56 }
  57
  58 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
  59 {
  60         struct btrfs_node *node = btrfs_buffer_node(buf);
  61         if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
  62                 printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
  63                        bh_blocknr(buf), btrfs_header_blocknr(&node->header));
  64                 BUG();
  65         }
  66         return 0;
  67 }
  68
  69 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
  70 {
  71         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
  72         int blockbits = root->fs_info->sb->s_blocksize_bits;
  73         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
  74         struct page *page;
  75         struct buffer_head *bh;
  76         struct buffer_head *head;
  77         struct buffer_head *ret = NULL;
  78
  79
  80         page = find_lock_page(mapping, index);
  81         if (!page)
  82                 return NULL;
  83
  84         if (!page_has_buffers(page))
  85                 goto out_unlock;
  86
  87         head = page_buffers(page);
  88         bh = head;
  89         do {
  90                 if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
  91                         ret = bh;
  92                         get_bh(bh);
  93                         goto out_unlock;
  94                 }
  95                 bh = bh->b_this_page;
  96         } while (bh != head);
  97 out_unlock:
  98         unlock_page(page);
  99         if (ret) {
 100                 touch_buffer(ret);
 101         }
 102         page_cache_release(page);
 103         return ret;
 104 }
 105
 106 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
 107                              u64 logical)
 108 {
 109         struct dev_lookup *lookup[2];
 110
 111         int ret;
 112
 113         root = root->fs_info->dev_root;
 114         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
 115                                      (void **)lookup,
 116                                      (unsigned long)logical,
 117                                      ARRAY_SIZE(lookup));
 118         if (ret == 0 || lookup[0]->block_start > logical ||
 119             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
 120                 ret = -ENOENT;
 121                 goto out;
 122         }
 123         bh->b_bdev = lookup[0]->bdev;
 124         bh->b_blocknr = logical - lookup[0]->block_start;
 125         set_buffer_mapped(bh);
 126         ret = 0;
 127 out:
 128         return ret;
 129 }
 130
 131 struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
 132                                                  u64 blocknr)
 133 {
 134         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 135         int blockbits = root->fs_info->sb->s_blocksize_bits;
 136         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
 137         struct page *page;
 138         struct buffer_head *bh;
 139         struct buffer_head *head;
 140         struct buffer_head *ret = NULL;
 141         int err;
 142         u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
 143
 144         page = grab_cache_page(mapping, index);
 145         if (!page)
 146                 return NULL;
 147
 148         if (!page_has_buffers(page))
 149                 create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
 150         head = page_buffers(page);
 151         bh = head;
 152         do {
 153                 if (!buffer_mapped(bh)) {
 154                         err = btrfs_map_bh_to_logical(root, bh, first_block);
 155                         BUG_ON(err);
 156                 }
 157                 if (bh_blocknr(bh) == blocknr) {
 158                         ret = bh;
 159                         get_bh(bh);
 160                         goto out_unlock;
 161                 }
 162                 bh = bh->b_this_page;
 163                 first_block++;
 164         } while (bh != head);
 165 out_unlock:
 166         unlock_page(page);
 167         if (ret)
 168                 touch_buffer(ret);
 169         page_cache_release(page);
 170         return ret;
 171 }
 172
 173 static int btree_get_block(struct inode *inode, sector_t iblock,
 174                            struct buffer_head *bh, int create)
 175 {
 176         int err;
 177         struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
 178         err = btrfs_map_bh_to_logical(root, bh, iblock);
 179         return err;
 180 }
 181
 182 int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
 183                     char *result)
 184 {
 185         struct scatterlist sg;
 186         struct crypto_hash *tfm = root->fs_info->hash_tfm;
 187         struct hash_desc desc;
 188         int ret;
 189
 190         desc.tfm = tfm;
 191         desc.flags = 0;
 192         sg_init_one(&sg, data, len);
 193         spin_lock(&root->fs_info->hash_lock);
 194         ret = crypto_hash_digest(&desc, &sg, 1, result);
 195         spin_unlock(&root->fs_info->hash_lock);
 196         if (ret) {
 197                 printk("sha256 digest failed\n");
 198         }
 199         return ret;
 200 }
 201 static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
 202                            int verify)
 203 {
 204         char result[BTRFS_CSUM_SIZE];
 205         int ret;
 206         struct btrfs_node *node;
 207
 208         ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
 209                               bh->b_size - BTRFS_CSUM_SIZE, result);
 210         if (ret)
 211                 return ret;
 212         if (verify) {
 213                 if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
 214                         printk("checksum verify failed on %Lu\n",
 215                                bh_blocknr(bh));
 216                         return 1;
 217                 }
 218         } else {
 219                 node = btrfs_buffer_node(bh);
 220                 memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
 221         }
 222         return 0;
 223 }
 224
 225 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 226 {
 227         struct buffer_head *bh;
 228         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 229         struct buffer_head *head;
 230         if (!page_has_buffers(page)) {
 231                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 232                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 233         }
 234         head = page_buffers(page);
 235         bh = head;
 236         do {
 237                 if (buffer_dirty(bh))
 238                         csum_tree_block(root, bh, 0);
 239                 bh = bh->b_this_page;
 240         } while (bh != head);
 241         return block_write_full_page(page, btree_get_block, wbc);
 242 }
 243
 244 static int btree_readpage(struct file * file, struct page * page)
 245 {
 246         return block_read_full_page(page, btree_get_block);
 247 }
 248
 249 static struct address_space_operations btree_aops = {
 250         .readpage       = btree_readpage,
 251         .writepage      = btree_writepage,
 252         .sync_page      = block_sync_page,
 253 };
 254
 255 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
 256 {
 257         struct buffer_head *bh = NULL;
 258
 259         bh = btrfs_find_create_tree_block(root, blocknr);
 260         if (!bh)
 261                 return bh;
 262         if (buffer_uptodate(bh))
 263                 goto uptodate;
 264         lock_buffer(bh);
 265         if (!buffer_uptodate(bh)) {
 266                 get_bh(bh);
 267                 bh->b_end_io = end_buffer_read_sync;
 268                 submit_bh(READ, bh);
 269                 wait_on_buffer(bh);
 270                 if (!buffer_uptodate(bh))
 271                         goto fail;
 272                 csum_tree_block(root, bh, 1);
 273         } else {
 274                 unlock_buffer(bh);
 275         }
 276 uptodate:
 277         if (check_tree_block(root, bh))
 278                 BUG();
 279         return bh;
 280 fail:
 281         brelse(bh);
 282         return NULL;
 283 }
 284
 285 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 286                      struct buffer_head *buf)
 287 {
 288         WARN_ON(atomic_read(&buf->b_count) == 0);
 289         mark_buffer_dirty(buf);
 290         return 0;
 291 }
 292
 293 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 294                      struct buffer_head *buf)
 295 {
 296         WARN_ON(atomic_read(&buf->b_count) == 0);
 297         clear_buffer_dirty(buf);
 298         return 0;
 299 }
 300
 301 static int __setup_root(int blocksize,
 302                         struct btrfs_root *root,
 303                         struct btrfs_fs_info *fs_info,
 304                         u64 objectid)
 305 {
 306         root->node = NULL;
 307         root->inode = NULL;
 308         root->commit_root = NULL;
 309         root->blocksize = blocksize;
 310         root->ref_cows = 0;
 311         root->fs_info = fs_info;
 312         root->objectid = objectid;
 313         root->last_trans = 0;
 314         root->highest_inode = 0;
 315         root->last_inode_alloc = 0;
 316         memset(&root->root_key, 0, sizeof(root->root_key));
 317         memset(&root->root_item, 0, sizeof(root->root_item));
 318         return 0;
 319 }
 320
 321 static int find_and_setup_root(int blocksize,
 322                                struct btrfs_root *tree_root,
 323                                struct btrfs_fs_info *fs_info,
 324                                u64 objectid,
 325                                struct btrfs_root *root)
 326 {
 327         int ret;
 328
 329         __setup_root(blocksize, root, fs_info, objectid);
 330         ret = btrfs_find_last_root(tree_root, objectid,
 331                                    &root->root_item, &root->root_key);
 332         BUG_ON(ret);
 333
 334         root->node = read_tree_block(root,
 335                                      btrfs_root_blocknr(&root->root_item));
 336         BUG_ON(!root->node);
 337         return 0;
 338 }
 339
 340 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 341                                       struct btrfs_key *location)
 342 {
 343         struct btrfs_root *root;
 344         struct btrfs_root *tree_root = fs_info->tree_root;
 345         struct btrfs_path *path;
 346         struct btrfs_leaf *l;
 347         u64 highest_inode;
 348         int ret = 0;
 349
 350 printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
 351         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 352                                  (unsigned long)location->objectid);
 353         if (root) {
 354 printk("found %p in cache\n", root);
 355                 return root;
 356         }
 357         root = kmalloc(sizeof(*root), GFP_NOFS);
 358         if (!root) {
 359 printk("failed1\n");
 360                 return ERR_PTR(-ENOMEM);
 361         }
 362         if (location->offset == (u64)-1) {
 363                 ret = find_and_setup_root(fs_info->sb->s_blocksize,
 364                                           fs_info->tree_root, fs_info,
 365                                           location->objectid, root);
 366                 if (ret) {
 367 printk("failed2\n");
 368                         kfree(root);
 369                         return ERR_PTR(ret);
 370                 }
 371                 goto insert;
 372         }
 373
 374         __setup_root(fs_info->sb->s_blocksize, root, fs_info,
 375                      location->objectid);
 376
 377         path = btrfs_alloc_path();
 378         BUG_ON(!path);
 379         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 380         if (ret != 0) {
 381 printk("internal search_slot gives us %d\n", ret);
 382                 if (ret > 0)
 383                         ret = -ENOENT;
 384                 goto out;
 385         }
 386         l = btrfs_buffer_leaf(path->nodes[0]);
 387         memcpy(&root->root_item,
 388                btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
 389                sizeof(root->root_item));
 390         memcpy(&root->root_key, location, sizeof(*location));
 391         ret = 0;
 392 out:
 393         btrfs_release_path(root, path);
 394         btrfs_free_path(path);
 395         if (ret) {
 396                 kfree(root);
 397                 return ERR_PTR(ret);
 398         }
 399         root->node = read_tree_block(root,
 400                                      btrfs_root_blocknr(&root->root_item));
 401         BUG_ON(!root->node);
 402 insert:
 403 printk("inserting %p\n", root);
 404         root->ref_cows = 1;
 405         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 406                                 (unsigned long)root->root_key.objectid,
 407                                 root);
 408         if (ret) {
 409 printk("radix_tree_insert gives us %d\n", ret);
 410                 brelse(root->node);
 411                 kfree(root);
 412                 return ERR_PTR(ret);
 413         }
 414         ret = btrfs_find_highest_inode(root, &highest_inode);
 415         if (ret == 0) {
 416                 root->highest_inode = highest_inode;
 417                 root->last_inode_alloc = highest_inode;
 418 printk("highest inode is %Lu\n", highest_inode);
 419         }
 420 printk("all worked\n");
 421         return root;
 422 }
 423
 424 static int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 425                            u64 block_start, u64 num_blocks,
 426                            char *filename, int name_len)
 427 {
 428         char *null_filename;
 429         struct block_device *bdev;
 430         int ret;
 431
 432         null_filename = kmalloc(name_len + 1, GFP_NOFS);
 433         if (!null_filename)
 434                 return -ENOMEM;
 435         memcpy(null_filename, filename, name_len);
 436         null_filename[name_len] = '\0';
 437
 438         bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
 439         if (IS_ERR(bdev)) {
 440                 ret = PTR_ERR(bdev);
 441                 goto out;
 442         }
 443         set_blocksize(bdev, root->fs_info->sb->s_blocksize);
 444         ret = btrfs_insert_dev_radix(root, bdev, device_id,
 445                                      block_start, num_blocks);
 446         BUG_ON(ret);
 447         ret = 0;
 448 out:
 449         kfree(null_filename);
 450         return ret;
 451 }
 452
 453 static int read_device_info(struct btrfs_root *root)
 454 {
 455         struct btrfs_path *path;
 456         int ret;
 457         struct btrfs_key key;
 458         struct btrfs_leaf *leaf;
 459         struct btrfs_device_item *dev_item;
 460         int nritems;
 461         int slot;
 462
 463         root = root->fs_info->dev_root;
 464
 465         path = btrfs_alloc_path();
 466         if (!path)
 467                 return -ENOMEM;
 468         key.objectid = 0;
 469         key.offset = 0;
 470         key.flags = 0;
 471         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 472
 473         mutex_lock(&root->fs_info->fs_mutex);
 474         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 475         leaf = btrfs_buffer_leaf(path->nodes[0]);
 476         nritems = btrfs_header_nritems(&leaf->header);
 477         while(1) {
 478                 slot = path->slots[0];
 479                 if (slot >= nritems) {
 480                         ret = btrfs_next_leaf(root, path);
 481                         if (ret)
 482                                 break;
 483                         leaf = btrfs_buffer_leaf(path->nodes[0]);
 484                         nritems = btrfs_header_nritems(&leaf->header);
 485                         slot = path->slots[0];
 486                 }
 487                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 488                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 489                         path->slots[0]++;
 490                         continue;
 491                 }
 492                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 493 printk("found key %Lu %Lu\n", key.objectid, key.offset);
 494                 if (btrfs_device_id(dev_item) !=
 495                     btrfs_super_device_id(root->fs_info->disk_super)) {
 496                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 497                                               key.objectid, key.offset,
 498                                               (char *)(dev_item + 1),
 499                                               btrfs_device_pathlen(dev_item));
 500                         BUG_ON(ret);
 501                 }
 502                 path->slots[0]++;
 503         }
 504         btrfs_free_path(path);
 505         mutex_unlock(&root->fs_info->fs_mutex);
 506         return 0;
 507 }
 508
 509 struct btrfs_root *open_ctree(struct super_block *sb)
 510 {
 511         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
 512                                                  GFP_NOFS);
 513         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
 514                                                  GFP_NOFS);
 515         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
 516                                                GFP_NOFS);
 517         struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
 518                                                 GFP_NOFS);
 519         int ret;
 520         struct btrfs_super_block *disk_super;
 521         struct dev_lookup *dev_lookup;
 522
 523         init_bit_radix(&fs_info->pinned_radix);
 524         init_bit_radix(&fs_info->pending_del_radix);
 525         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 526         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
 527         sb_set_blocksize(sb, 4096);
 528         fs_info->running_transaction = NULL;
 529         fs_info->tree_root = tree_root;
 530         fs_info->extent_root = extent_root;
 531         fs_info->dev_root = dev_root;
 532         fs_info->sb = sb;
 533         fs_info->btree_inode = new_inode(sb);
 534         fs_info->btree_inode->i_ino = 1;
 535         fs_info->btree_inode->i_nlink = 1;
 536         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
 537         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
 538         BTRFS_I(fs_info->btree_inode)->root = tree_root;
 539         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
 540                sizeof(struct btrfs_key));
 541         insert_inode_hash(fs_info->btree_inode);
 542         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 543         fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
 544         spin_lock_init(&fs_info->hash_lock);
 545         if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
 546                 printk("failed to allocate sha256 hash\n");
 547                 return NULL;
 548         }
 549         mutex_init(&fs_info->trans_mutex);
 550         mutex_init(&fs_info->fs_mutex);
 551         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 552         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 553
 554         __setup_root(sb->s_blocksize, dev_root,
 555                      fs_info, BTRFS_DEV_TREE_OBJECTID);
 556
 557         __setup_root(sb->s_blocksize, tree_root,
 558                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 559
 560         dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
 561         dev_lookup->block_start = 0;
 562         dev_lookup->num_blocks = (u32)-2;
 563         dev_lookup->bdev = sb->s_bdev;
 564         dev_lookup->device_id = 0;
 565         ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
 566         BUG_ON(ret);
 567         fs_info->sb_buffer = read_tree_block(tree_root,
 568                                              BTRFS_SUPER_INFO_OFFSET /
 569                                              sb->s_blocksize);
 570
 571         if (!fs_info->sb_buffer)
 572                 return NULL;
 573         disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
 574         if (!btrfs_super_root(disk_super))
 575                 return NULL;
 576
 577         i_size_write(fs_info->btree_inode,
 578                      btrfs_super_total_blocks(disk_super) <<
 579                      fs_info->btree_inode->i_blkbits);
 580
 581         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
 582         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
 583         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
 584         dev_lookup->device_id = btrfs_super_device_id(disk_super);
 585
 586         ret = radix_tree_insert(&fs_info->dev_radix,
 587                                 dev_lookup->block_start +
 588                                 dev_lookup->num_blocks - 1, dev_lookup);
 589         BUG_ON(ret);
 590
 591         fs_info->disk_super = disk_super;
 592
 593         dev_root->node = read_tree_block(tree_root,
 594                                           btrfs_super_device_root(disk_super));
 595
 596         ret = read_device_info(dev_root);
 597         BUG_ON(ret);
 598
 599         tree_root->node = read_tree_block(tree_root,
 600                                           btrfs_super_root(disk_super));
 601         BUG_ON(!tree_root->node);
 602
 603         mutex_lock(&fs_info->fs_mutex);
 604         ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
 605                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
 606         BUG_ON(ret);
 607
 608         fs_info->generation = btrfs_super_generation(disk_super) + 1;
 609         memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
 610         kobj_set_kset_s(fs_info, btrfs_subsys);
 611         kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
 612         kobject_register(&fs_info->kobj);
 613         mutex_unlock(&fs_info->fs_mutex);
 614         return tree_root;
 615 }
 616
 617 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 618                       *root)
 619 {
 620         struct buffer_head *bh = root->fs_info->sb_buffer;
 621
 622         btrfs_set_super_root(root->fs_info->disk_super,
 623                              bh_blocknr(root->fs_info->tree_root->node));
 624         lock_buffer(bh);
 625         WARN_ON(atomic_read(&bh->b_count) < 1);
 626         clear_buffer_dirty(bh);
 627         csum_tree_block(root, bh, 0);
 628         bh->b_end_io = end_buffer_write_sync;
 629         get_bh(bh);
 630         submit_bh(WRITE, bh);
 631         wait_on_buffer(bh);
 632         if (!buffer_uptodate(bh)) {
 633                 WARN_ON(1);
 634                 return -EIO;
 635         }
 636         return 0;
 637 }
 638
 639 static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 640 {
 641         radix_tree_delete(&fs_info->fs_roots_radix,
 642                           (unsigned long)root->root_key.objectid);
 643         if (root->inode)
 644                 iput(root->inode);
 645         if (root->node)
 646                 brelse(root->node);
 647         if (root->commit_root)
 648                 brelse(root->commit_root);
 649         kfree(root);
 650         return 0;
 651 }
 652
 653 int del_fs_roots(struct btrfs_fs_info *fs_info)
 654 {
 655         int ret;
 656         struct btrfs_root *gang[8];
 657         int i;
 658
 659         while(1) {
 660                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
 661                                              (void **)gang, 0,
 662                                              ARRAY_SIZE(gang));
 663                 if (!ret)
 664                         break;
 665                 for (i = 0; i < ret; i++)
 666                         free_fs_root(fs_info, gang[i]);
 667         }
 668         return 0;
 669 }
 670
 671 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 672 {
 673         struct dev_lookup *lookup[8];
 674         struct block_device *super_bdev = fs_info->sb->s_bdev;
 675         int ret;
 676         int i;
 677         while(1) {
 678                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 679                                              (void **)lookup, 0,
 680                                              ARRAY_SIZE(lookup));
 681                 if (!ret)
 682                         break;
 683                 for (i = 0; i < ret; i++) {
 684                         if (lookup[i]->bdev != super_bdev)
 685                                 close_bdev_excl(lookup[i]->bdev);
 686                         radix_tree_delete(&fs_info->dev_radix,
 687                                           lookup[i]->block_start +
 688                                           lookup[i]->num_blocks - 1);
 689                         kfree(lookup[i]);
 690                 }
 691         }
 692         return 0;
 693 }
 694
 695 int close_ctree(struct btrfs_root *root)
 696 {
 697         int ret;
 698         struct btrfs_trans_handle *trans;
 699         struct btrfs_fs_info *fs_info = root->fs_info;
 700
 701         mutex_lock(&fs_info->fs_mutex);
 702         trans = btrfs_start_transaction(root, 1);
 703         btrfs_commit_transaction(trans, root);
 704         /* run commit again to  drop the original snapshot */
 705         trans = btrfs_start_transaction(root, 1);
 706         btrfs_commit_transaction(trans, root);
 707         ret = btrfs_write_and_wait_transaction(NULL, root);
 708         BUG_ON(ret);
 709         write_ctree_super(NULL, root);
 710         mutex_unlock(&fs_info->fs_mutex);
 711
 712         if (fs_info->extent_root->node)
 713                 btrfs_block_release(fs_info->extent_root,
 714                                     fs_info->extent_root->node);
 715         if (fs_info->dev_root->node)
 716                 btrfs_block_release(fs_info->dev_root,
 717                                     fs_info->dev_root->node);
 718         if (fs_info->tree_root->node)
 719                 btrfs_block_release(fs_info->tree_root,
 720                                     fs_info->tree_root->node);
 721         btrfs_block_release(root, fs_info->sb_buffer);
 722         crypto_free_hash(fs_info->hash_tfm);
 723         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
 724         iput(fs_info->btree_inode);
 725
 726         free_dev_radix(fs_info);
 727         del_fs_roots(fs_info);
 728         kfree(fs_info->extent_root);
 729         kfree(fs_info->tree_root);
 730         kobject_unregister(&fs_info->kobj);
 731         return 0;
 732 }
 733
 734 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
 735 {
 736         brelse(buf);
 737 }
 738