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         int ret;
  28
  29         lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
  30         if (!lookup)
  31                 return -ENOMEM;
  32         lookup->block_start = block_start;
  33         lookup->num_blocks = num_blocks;
  34         lookup->bdev = bdev;
  35         lookup->device_id = device_id;
  36
  37         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  38                                 num_blocks - 1, lookup);
  39         return ret;
  40 }
  41
  42 u64 bh_blocknr(struct buffer_head *bh)
  43 {
  44         int blkbits = bh->b_page->mapping->host->i_blkbits;
  45         u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
  46         unsigned long offset;
  47
  48         if (PageHighMem(bh->b_page))
  49                 offset = (unsigned long)bh->b_data;
  50         else
  51                 offset = bh->b_data - (char *)page_address(bh->b_page);
  52         blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
  53         return blocknr;
  54 }
  55
  56 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
  57 {
  58         struct btrfs_node *node = btrfs_buffer_node(buf);
  59         if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
  60                 printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
  61                        bh_blocknr(buf), btrfs_header_blocknr(&node->header));
  62                 BUG();
  63         }
  64         return 0;
  65 }
  66
  67 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
  68 {
  69         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
  70         int blockbits = root->fs_info->sb->s_blocksize_bits;
  71         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
  72         struct page *page;
  73         struct buffer_head *bh;
  74         struct buffer_head *head;
  75         struct buffer_head *ret = NULL;
  76
  77
  78         page = find_lock_page(mapping, index);
  79         if (!page)
  80                 return NULL;
  81
  82         if (!page_has_buffers(page))
  83                 goto out_unlock;
  84
  85         head = page_buffers(page);
  86         bh = head;
  87         do {
  88                 if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
  89                         ret = bh;
  90                         get_bh(bh);
  91                         goto out_unlock;
  92                 }
  93                 bh = bh->b_this_page;
  94         } while (bh != head);
  95 out_unlock:
  96         unlock_page(page);
  97         if (ret) {
  98                 touch_buffer(ret);
  99         }
 100         page_cache_release(page);
 101         return ret;
 102 }
 103
 104 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
 105                              u64 logical)
 106 {
 107         struct dev_lookup *lookup[2];
 108
 109         int ret;
 110
 111         if (logical == 0) {
 112                 bh->b_bdev = NULL;
 113                 bh->b_blocknr = 0;
 114                 set_buffer_mapped(bh);
 115                 return 0;
 116         }
 117         root = root->fs_info->dev_root;
 118         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
 119                                      (void **)lookup,
 120                                      (unsigned long)logical,
 121                                      ARRAY_SIZE(lookup));
 122         if (ret == 0 || lookup[0]->block_start > logical ||
 123             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
 124                 ret = -ENOENT;
 125                 goto out;
 126         }
 127         bh->b_bdev = lookup[0]->bdev;
 128         bh->b_blocknr = logical - lookup[0]->block_start;
 129         set_buffer_mapped(bh);
 130         ret = 0;
 131 out:
 132         return ret;
 133 }
 134
 135 struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
 136                                                  u64 blocknr)
 137 {
 138         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 139         int blockbits = root->fs_info->sb->s_blocksize_bits;
 140         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
 141         struct page *page;
 142         struct buffer_head *bh;
 143         struct buffer_head *head;
 144         struct buffer_head *ret = NULL;
 145         int err;
 146         u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
 147
 148         page = grab_cache_page(mapping, index);
 149         if (!page)
 150                 return NULL;
 151
 152         if (!page_has_buffers(page))
 153                 create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
 154         head = page_buffers(page);
 155         bh = head;
 156         do {
 157                 if (!buffer_mapped(bh)) {
 158                         err = btrfs_map_bh_to_logical(root, bh, first_block);
 159                         BUG_ON(err);
 160                 }
 161                 if (bh_blocknr(bh) == blocknr) {
 162                         ret = bh;
 163                         get_bh(bh);
 164                         goto out_unlock;
 165                 }
 166                 bh = bh->b_this_page;
 167                 first_block++;
 168         } while (bh != head);
 169 out_unlock:
 170         unlock_page(page);
 171         if (ret)
 172                 touch_buffer(ret);
 173         page_cache_release(page);
 174         return ret;
 175 }
 176
 177 static int btree_get_block(struct inode *inode, sector_t iblock,
 178                            struct buffer_head *bh, int create)
 179 {
 180         int err;
 181         struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
 182         err = btrfs_map_bh_to_logical(root, bh, iblock);
 183         return err;
 184 }
 185
 186 int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
 187                     char *result)
 188 {
 189         struct scatterlist sg;
 190         struct crypto_hash *tfm = root->fs_info->hash_tfm;
 191         struct hash_desc desc;
 192         int ret;
 193
 194         desc.tfm = tfm;
 195         desc.flags = 0;
 196         sg_init_one(&sg, data, len);
 197         spin_lock(&root->fs_info->hash_lock);
 198         ret = crypto_hash_digest(&desc, &sg, 1, result);
 199         spin_unlock(&root->fs_info->hash_lock);
 200         if (ret) {
 201                 printk("sha256 digest failed\n");
 202         }
 203         return ret;
 204 }
 205 static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
 206                            int verify)
 207 {
 208         char result[BTRFS_CSUM_SIZE];
 209         int ret;
 210         struct btrfs_node *node;
 211
 212         ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
 213                               bh->b_size - BTRFS_CSUM_SIZE, result);
 214         if (ret)
 215                 return ret;
 216         if (verify) {
 217                 if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
 218                         printk("checksum verify failed on %Lu\n",
 219                                bh_blocknr(bh));
 220                         return 1;
 221                 }
 222         } else {
 223                 node = btrfs_buffer_node(bh);
 224                 memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
 225         }
 226         return 0;
 227 }
 228
 229 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 230 {
 231         struct buffer_head *bh;
 232         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 233         struct buffer_head *head;
 234         if (!page_has_buffers(page)) {
 235                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 236                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 237         }
 238         head = page_buffers(page);
 239         bh = head;
 240         do {
 241                 if (buffer_dirty(bh))
 242                         csum_tree_block(root, bh, 0);
 243                 bh = bh->b_this_page;
 244         } while (bh != head);
 245         return block_write_full_page(page, btree_get_block, wbc);
 246 }
 247
 248 static int btree_readpage(struct file * file, struct page * page)
 249 {
 250         return block_read_full_page(page, btree_get_block);
 251 }
 252
 253 static struct address_space_operations btree_aops = {
 254         .readpage       = btree_readpage,
 255         .writepage      = btree_writepage,
 256         .sync_page      = block_sync_page,
 257 };
 258
 259 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
 260 {
 261         struct buffer_head *bh = NULL;
 262
 263         bh = btrfs_find_create_tree_block(root, blocknr);
 264         if (!bh)
 265                 return bh;
 266         if (buffer_uptodate(bh))
 267                 goto uptodate;
 268         lock_buffer(bh);
 269         if (!buffer_uptodate(bh)) {
 270                 get_bh(bh);
 271                 bh->b_end_io = end_buffer_read_sync;
 272                 submit_bh(READ, bh);
 273                 wait_on_buffer(bh);
 274                 if (!buffer_uptodate(bh))
 275                         goto fail;
 276                 csum_tree_block(root, bh, 1);
 277         } else {
 278                 unlock_buffer(bh);
 279         }
 280 uptodate:
 281         if (check_tree_block(root, bh))
 282                 BUG();
 283         return bh;
 284 fail:
 285         brelse(bh);
 286         return NULL;
 287 }
 288
 289 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 290                      struct buffer_head *buf)
 291 {
 292         WARN_ON(atomic_read(&buf->b_count) == 0);
 293         mark_buffer_dirty(buf);
 294         return 0;
 295 }
 296
 297 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 298                      struct buffer_head *buf)
 299 {
 300         WARN_ON(atomic_read(&buf->b_count) == 0);
 301         clear_buffer_dirty(buf);
 302         return 0;
 303 }
 304
 305 static int __setup_root(int blocksize,
 306                         struct btrfs_root *root,
 307                         struct btrfs_fs_info *fs_info,
 308                         u64 objectid)
 309 {
 310         root->node = NULL;
 311         root->inode = NULL;
 312         root->commit_root = NULL;
 313         root->blocksize = blocksize;
 314         root->ref_cows = 0;
 315         root->fs_info = fs_info;
 316         root->objectid = objectid;
 317         root->last_trans = 0;
 318         root->highest_inode = 0;
 319         root->last_inode_alloc = 0;
 320         memset(&root->root_key, 0, sizeof(root->root_key));
 321         memset(&root->root_item, 0, sizeof(root->root_item));
 322         return 0;
 323 }
 324
 325 static int find_and_setup_root(int blocksize,
 326                                struct btrfs_root *tree_root,
 327                                struct btrfs_fs_info *fs_info,
 328                                u64 objectid,
 329                                struct btrfs_root *root)
 330 {
 331         int ret;
 332
 333         __setup_root(blocksize, root, fs_info, objectid);
 334         ret = btrfs_find_last_root(tree_root, objectid,
 335                                    &root->root_item, &root->root_key);
 336         BUG_ON(ret);
 337
 338         root->node = read_tree_block(root,
 339                                      btrfs_root_blocknr(&root->root_item));
 340         BUG_ON(!root->node);
 341         return 0;
 342 }
 343
 344 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 345                                       struct btrfs_key *location)
 346 {
 347         struct btrfs_root *root;
 348         struct btrfs_root *tree_root = fs_info->tree_root;
 349         struct btrfs_path *path;
 350         struct btrfs_leaf *l;
 351         u64 highest_inode;
 352         int ret = 0;
 353
 354 printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
 355         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 356                                  (unsigned long)location->objectid);
 357         if (root) {
 358 printk("found %p in cache\n", root);
 359                 return root;
 360         }
 361         root = kmalloc(sizeof(*root), GFP_NOFS);
 362         if (!root) {
 363 printk("failed1\n");
 364                 return ERR_PTR(-ENOMEM);
 365         }
 366         if (location->offset == (u64)-1) {
 367                 ret = find_and_setup_root(fs_info->sb->s_blocksize,
 368                                           fs_info->tree_root, fs_info,
 369                                           location->objectid, root);
 370                 if (ret) {
 371 printk("failed2\n");
 372                         kfree(root);
 373                         return ERR_PTR(ret);
 374                 }
 375                 goto insert;
 376         }
 377
 378         __setup_root(fs_info->sb->s_blocksize, root, fs_info,
 379                      location->objectid);
 380
 381         path = btrfs_alloc_path();
 382         BUG_ON(!path);
 383         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 384         if (ret != 0) {
 385 printk("internal search_slot gives us %d\n", ret);
 386                 if (ret > 0)
 387                         ret = -ENOENT;
 388                 goto out;
 389         }
 390         l = btrfs_buffer_leaf(path->nodes[0]);
 391         memcpy(&root->root_item,
 392                btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
 393                sizeof(root->root_item));
 394         memcpy(&root->root_key, location, sizeof(*location));
 395         ret = 0;
 396 out:
 397         btrfs_release_path(root, path);
 398         btrfs_free_path(path);
 399         if (ret) {
 400                 kfree(root);
 401                 return ERR_PTR(ret);
 402         }
 403         root->node = read_tree_block(root,
 404                                      btrfs_root_blocknr(&root->root_item));
 405         BUG_ON(!root->node);
 406 insert:
 407 printk("inserting %p\n", root);
 408         root->ref_cows = 1;
 409         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 410                                 (unsigned long)root->root_key.objectid,
 411                                 root);
 412         if (ret) {
 413 printk("radix_tree_insert gives us %d\n", ret);
 414                 brelse(root->node);
 415                 kfree(root);
 416                 return ERR_PTR(ret);
 417         }
 418         ret = btrfs_find_highest_inode(root, &highest_inode);
 419         if (ret == 0) {
 420                 root->highest_inode = highest_inode;
 421                 root->last_inode_alloc = highest_inode;
 422 printk("highest inode is %Lu\n", highest_inode);
 423         }
 424 printk("all worked\n");
 425         return root;
 426 }
 427
 428 static int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 429                            u64 block_start, u64 num_blocks,
 430                            char *filename, int name_len)
 431 {
 432         char *null_filename;
 433         struct block_device *bdev;
 434         int ret;
 435
 436         null_filename = kmalloc(name_len + 1, GFP_NOFS);
 437         if (!null_filename)
 438                 return -ENOMEM;
 439         memcpy(null_filename, filename, name_len);
 440         null_filename[name_len] = '\0';
 441
 442         bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
 443         if (IS_ERR(bdev)) {
 444                 ret = PTR_ERR(bdev);
 445                 goto out;
 446         }
 447         set_blocksize(bdev, root->fs_info->sb->s_blocksize);
 448         ret = btrfs_insert_dev_radix(root, bdev, device_id,
 449                                      block_start, num_blocks);
 450         BUG_ON(ret);
 451         ret = 0;
 452 out:
 453         kfree(null_filename);
 454         return ret;
 455 }
 456
 457 static int read_device_info(struct btrfs_root *root)
 458 {
 459         struct btrfs_path *path;
 460         int ret;
 461         struct btrfs_key key;
 462         struct btrfs_leaf *leaf;
 463         struct btrfs_device_item *dev_item;
 464         int nritems;
 465         int slot;
 466
 467         root = root->fs_info->dev_root;
 468
 469         path = btrfs_alloc_path();
 470         if (!path)
 471                 return -ENOMEM;
 472         key.objectid = 0;
 473         key.offset = 0;
 474         key.flags = 0;
 475         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 476
 477         mutex_lock(&root->fs_info->fs_mutex);
 478         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 479         leaf = btrfs_buffer_leaf(path->nodes[0]);
 480         nritems = btrfs_header_nritems(&leaf->header);
 481         while(1) {
 482                 slot = path->slots[0];
 483                 if (slot >= nritems) {
 484                         ret = btrfs_next_leaf(root, path);
 485                         if (ret)
 486                                 break;
 487                         leaf = btrfs_buffer_leaf(path->nodes[0]);
 488                         nritems = btrfs_header_nritems(&leaf->header);
 489                         slot = path->slots[0];
 490                 }
 491                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 492                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 493                         path->slots[0]++;
 494                         continue;
 495                 }
 496                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 497 printk("found key %Lu %Lu\n", key.objectid, key.offset);
 498                 if (btrfs_device_id(dev_item) !=
 499                     btrfs_super_device_id(root->fs_info->disk_super)) {
 500                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 501                                               key.objectid, key.offset,
 502                                               (char *)(dev_item + 1),
 503                                               btrfs_device_pathlen(dev_item));
 504                         BUG_ON(ret);
 505                 }
 506                 path->slots[0]++;
 507         }
 508         btrfs_free_path(path);
 509         mutex_unlock(&root->fs_info->fs_mutex);
 510         return 0;
 511 }
 512
 513 struct btrfs_root *open_ctree(struct super_block *sb)
 514 {
 515         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
 516                                                  GFP_NOFS);
 517         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
 518                                                  GFP_NOFS);
 519         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
 520                                                GFP_NOFS);
 521         struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
 522                                                 GFP_NOFS);
 523         int ret;
 524         struct btrfs_super_block *disk_super;
 525         struct dev_lookup *dev_lookup;
 526
 527         init_bit_radix(&fs_info->pinned_radix);
 528         init_bit_radix(&fs_info->pending_del_radix);
 529         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 530         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
 531         INIT_LIST_HEAD(&fs_info->trans_list);
 532         sb_set_blocksize(sb, 4096);
 533         fs_info->running_transaction = NULL;
 534         fs_info->tree_root = tree_root;
 535         fs_info->extent_root = extent_root;
 536         fs_info->dev_root = dev_root;
 537         fs_info->sb = sb;
 538         fs_info->btree_inode = new_inode(sb);
 539         fs_info->btree_inode->i_ino = 1;
 540         fs_info->btree_inode->i_nlink = 1;
 541         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
 542         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
 543         fs_info->do_barriers = 1;
 544         BTRFS_I(fs_info->btree_inode)->root = tree_root;
 545         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
 546                sizeof(struct btrfs_key));
 547         insert_inode_hash(fs_info->btree_inode);
 548         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 549         fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
 550         spin_lock_init(&fs_info->hash_lock);
 551         if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
 552                 printk("failed to allocate sha256 hash\n");
 553                 return NULL;
 554         }
 555         mutex_init(&fs_info->trans_mutex);
 556         mutex_init(&fs_info->fs_mutex);
 557         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 558         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 559
 560         __setup_root(sb->s_blocksize, dev_root,
 561                      fs_info, BTRFS_DEV_TREE_OBJECTID);
 562
 563         __setup_root(sb->s_blocksize, tree_root,
 564                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 565
 566         dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
 567         dev_lookup->block_start = 0;
 568         dev_lookup->num_blocks = (u32)-2;
 569         dev_lookup->bdev = sb->s_bdev;
 570         dev_lookup->device_id = 0;
 571         ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
 572         BUG_ON(ret);
 573         fs_info->sb_buffer = read_tree_block(tree_root,
 574                                              BTRFS_SUPER_INFO_OFFSET /
 575                                              sb->s_blocksize);
 576
 577         if (!fs_info->sb_buffer)
 578                 return NULL;
 579         disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
 580         if (!btrfs_super_root(disk_super))
 581                 return NULL;
 582
 583         i_size_write(fs_info->btree_inode,
 584                      btrfs_super_total_blocks(disk_super) <<
 585                      fs_info->btree_inode->i_blkbits);
 586
 587         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
 588         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
 589         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
 590         dev_lookup->device_id = btrfs_super_device_id(disk_super);
 591
 592         ret = radix_tree_insert(&fs_info->dev_radix,
 593                                 dev_lookup->block_start +
 594                                 dev_lookup->num_blocks - 1, dev_lookup);
 595         BUG_ON(ret);
 596
 597         fs_info->disk_super = disk_super;
 598
 599         dev_root->node = read_tree_block(tree_root,
 600                                           btrfs_super_device_root(disk_super));
 601
 602         ret = read_device_info(dev_root);
 603         BUG_ON(ret);
 604
 605         tree_root->node = read_tree_block(tree_root,
 606                                           btrfs_super_root(disk_super));
 607         BUG_ON(!tree_root->node);
 608
 609         mutex_lock(&fs_info->fs_mutex);
 610         ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
 611                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
 612         BUG_ON(ret);
 613
 614         fs_info->generation = btrfs_super_generation(disk_super) + 1;
 615         memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
 616         kobj_set_kset_s(fs_info, btrfs_subsys);
 617         kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
 618         kobject_register(&fs_info->kobj);
 619         mutex_unlock(&fs_info->fs_mutex);
 620         return tree_root;
 621 }
 622
 623 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 624                       *root)
 625 {
 626         int ret;
 627         struct buffer_head *bh = root->fs_info->sb_buffer;
 628
 629         btrfs_set_super_root(root->fs_info->disk_super,
 630                              bh_blocknr(root->fs_info->tree_root->node));
 631         lock_buffer(bh);
 632         WARN_ON(atomic_read(&bh->b_count) < 1);
 633         clear_buffer_dirty(bh);
 634         csum_tree_block(root, bh, 0);
 635         bh->b_end_io = end_buffer_write_sync;
 636         get_bh(bh);
 637         if (root->fs_info->do_barriers)
 638                 ret = submit_bh(WRITE_BARRIER, bh);
 639         else
 640                 ret = submit_bh(WRITE, bh);
 641         if (ret == -EOPNOTSUPP) {
 642                 set_buffer_uptodate(bh);
 643                 root->fs_info->do_barriers = 0;
 644                 ret = submit_bh(WRITE, bh);
 645         }
 646         wait_on_buffer(bh);
 647         if (!buffer_uptodate(bh)) {
 648                 WARN_ON(1);
 649                 return -EIO;
 650         }
 651         return 0;
 652 }
 653
 654 static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 655 {
 656         radix_tree_delete(&fs_info->fs_roots_radix,
 657                           (unsigned long)root->root_key.objectid);
 658         if (root->inode)
 659                 iput(root->inode);
 660         if (root->node)
 661                 brelse(root->node);
 662         if (root->commit_root)
 663                 brelse(root->commit_root);
 664         kfree(root);
 665         return 0;
 666 }
 667
 668 int del_fs_roots(struct btrfs_fs_info *fs_info)
 669 {
 670         int ret;
 671         struct btrfs_root *gang[8];
 672         int i;
 673
 674         while(1) {
 675                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
 676                                              (void **)gang, 0,
 677                                              ARRAY_SIZE(gang));
 678                 if (!ret)
 679                         break;
 680                 for (i = 0; i < ret; i++)
 681                         free_fs_root(fs_info, gang[i]);
 682         }
 683         return 0;
 684 }
 685
 686 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 687 {
 688         struct dev_lookup *lookup[8];
 689         struct block_device *super_bdev = fs_info->sb->s_bdev;
 690         int ret;
 691         int i;
 692         while(1) {
 693                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 694                                              (void **)lookup, 0,
 695                                              ARRAY_SIZE(lookup));
 696                 if (!ret)
 697                         break;
 698                 for (i = 0; i < ret; i++) {
 699                         if (lookup[i]->bdev != super_bdev)
 700                                 close_bdev_excl(lookup[i]->bdev);
 701                         radix_tree_delete(&fs_info->dev_radix,
 702                                           lookup[i]->block_start +
 703                                           lookup[i]->num_blocks - 1);
 704                         kfree(lookup[i]);
 705                 }
 706         }
 707         return 0;
 708 }
 709
 710 int close_ctree(struct btrfs_root *root)
 711 {
 712         int ret;
 713         struct btrfs_trans_handle *trans;
 714         struct btrfs_fs_info *fs_info = root->fs_info;
 715
 716         mutex_lock(&fs_info->fs_mutex);
 717         trans = btrfs_start_transaction(root, 1);
 718         btrfs_commit_transaction(trans, root);
 719         /* run commit again to  drop the original snapshot */
 720         trans = btrfs_start_transaction(root, 1);
 721         btrfs_commit_transaction(trans, root);
 722         ret = btrfs_write_and_wait_transaction(NULL, root);
 723         BUG_ON(ret);
 724         write_ctree_super(NULL, root);
 725         mutex_unlock(&fs_info->fs_mutex);
 726
 727         if (fs_info->extent_root->node)
 728                 btrfs_block_release(fs_info->extent_root,
 729                                     fs_info->extent_root->node);
 730         if (fs_info->dev_root->node)
 731                 btrfs_block_release(fs_info->dev_root,
 732                                     fs_info->dev_root->node);
 733         if (fs_info->tree_root->node)
 734                 btrfs_block_release(fs_info->tree_root,
 735                                     fs_info->tree_root->node);
 736         btrfs_block_release(root, fs_info->sb_buffer);
 737         crypto_free_hash(fs_info->hash_tfm);
 738         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
 739         iput(fs_info->btree_inode);
 740
 741         free_dev_radix(fs_info);
 742         del_fs_roots(fs_info);
 743         kfree(fs_info->extent_root);
 744         kfree(fs_info->tree_root);
 745         kobject_unregister(&fs_info->kobj);
 746         return 0;
 747 }
 748
 749 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
 750 {
 751         brelse(buf);
 752 }
 753