fs/btrfs/super.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/module.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/highmem.h>
  25 #include <linux/time.h>
  26 #include <linux/init.h>
  27 #include <linux/string.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mount.h>
  31 #include <linux/mpage.h>
  32 #include <linux/swap.h>
  33 #include <linux/writeback.h>
  34 #include <linux/statfs.h>
  35 #include <linux/compat.h>
  36 #include <linux/parser.h>
  37 #include <linux/ctype.h>
  38 #include <linux/namei.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/version.h>
  41 #include "compat.h"
  42 #include "ctree.h"
  43 #include "disk-io.h"
  44 #include "transaction.h"
  45 #include "btrfs_inode.h"
  46 #include "ioctl.h"
  47 #include "print-tree.h"
  48 #include "xattr.h"
  49 #include "volumes.h"
  50 #include "version.h"
  51 #include "export.h"
  52 #include "compression.h"
  53
  54 #define BTRFS_SUPER_MAGIC 0x9123683E
  55
  56 static struct super_operations btrfs_super_ops;
  57
  58 static void btrfs_put_super(struct super_block *sb)
  59 {
  60         struct btrfs_root *root = btrfs_sb(sb);
  61         int ret;
  62
  63         ret = close_ctree(root);
  64         sb->s_fs_info = NULL;
  65 }
  66
  67 enum {
  68         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
  69         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
  70         Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_compress, Opt_err,
  71 };
  72
  73 static match_table_t tokens = {
  74         {Opt_degraded, "degraded"},
  75         {Opt_subvol, "subvol=%s"},
  76         {Opt_device, "device=%s"},
  77         {Opt_nodatasum, "nodatasum"},
  78         {Opt_nodatacow, "nodatacow"},
  79         {Opt_nobarrier, "nobarrier"},
  80         {Opt_max_extent, "max_extent=%s"},
  81         {Opt_max_inline, "max_inline=%s"},
  82         {Opt_alloc_start, "alloc_start=%s"},
  83         {Opt_thread_pool, "thread_pool=%d"},
  84         {Opt_compress, "compress"},
  85         {Opt_ssd, "ssd"},
  86         {Opt_noacl, "noacl"},
  87         {Opt_err, NULL},
  88 };
  89
  90 u64 btrfs_parse_size(char *str)
  91 {
  92         u64 res;
  93         int mult = 1;
  94         char *end;
  95         char last;
  96
  97         res = simple_strtoul(str, &end, 10);
  98
  99         last = end[0];
 100         if (isalpha(last)) {
 101                 last = tolower(last);
 102                 switch (last) {
 103                 case 'g':
 104                         mult *= 1024;
 105                 case 'm':
 106                         mult *= 1024;
 107                 case 'k':
 108                         mult *= 1024;
 109                 }
 110                 res = res * mult;
 111         }
 112         return res;
 113 }
 114
 115 /*
 116  * Regular mount options parser.  Everything that is needed only when
 117  * reading in a new superblock is parsed here.
 118  */
 119 int btrfs_parse_options(struct btrfs_root *root, char *options)
 120 {
 121         struct btrfs_fs_info *info = root->fs_info;
 122         substring_t args[MAX_OPT_ARGS];
 123         char *p, *num;
 124         int intarg;
 125
 126         if (!options)
 127                 return 0;
 128
 129         /*
 130          * strsep changes the string, duplicate it because parse_options
 131          * gets called twice
 132          */
 133         options = kstrdup(options, GFP_NOFS);
 134         if (!options)
 135                 return -ENOMEM;
 136
 137
 138         while ((p = strsep(&options, ",")) != NULL) {
 139                 int token;
 140                 if (!*p)
 141                         continue;
 142
 143                 token = match_token(p, tokens, args);
 144                 switch (token) {
 145                 case Opt_degraded:
 146                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 147                         btrfs_set_opt(info->mount_opt, DEGRADED);
 148                         break;
 149                 case Opt_subvol:
 150                 case Opt_device:
 151                         /*
 152                          * These are parsed by btrfs_parse_early_options
 153                          * and can be happily ignored here.
 154                          */
 155                         break;
 156                 case Opt_nodatasum:
 157                         printk(KERN_INFO "btrfs: setting nodatacsum\n");
 158                         btrfs_set_opt(info->mount_opt, NODATASUM);
 159                         break;
 160                 case Opt_nodatacow:
 161                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 162                         btrfs_set_opt(info->mount_opt, NODATACOW);
 163                         btrfs_set_opt(info->mount_opt, NODATASUM);
 164                         break;
 165                 case Opt_compress:
 166                         printk(KERN_INFO "btrfs: use compression\n");
 167                         btrfs_set_opt(info->mount_opt, COMPRESS);
 168                         break;
 169                 case Opt_ssd:
 170                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 171                         btrfs_set_opt(info->mount_opt, SSD);
 172                         break;
 173                 case Opt_nobarrier:
 174                         printk(KERN_INFO "btrfs: turning off barriers\n");
 175                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 176                         break;
 177                 case Opt_thread_pool:
 178                         intarg = 0;
 179                         match_int(&args[0], &intarg);
 180                         if (intarg) {
 181                                 info->thread_pool_size = intarg;
 182                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 183                                        info->thread_pool_size);
 184                         }
 185                         break;
 186                 case Opt_max_extent:
 187                         num = match_strdup(&args[0]);
 188                         if (num) {
 189                                 info->max_extent = btrfs_parse_size(num);
 190                                 kfree(num);
 191
 192                                 info->max_extent = max_t(u64,
 193                                         info->max_extent, root->sectorsize);
 194                                 printk(KERN_INFO "btrfs: max_extent at %llu\n",
 195                                        info->max_extent);
 196                         }
 197                         break;
 198                 case Opt_max_inline:
 199                         num = match_strdup(&args[0]);
 200                         if (num) {
 201                                 info->max_inline = btrfs_parse_size(num);
 202                                 kfree(num);
 203
 204                                 if (info->max_inline) {
 205                                         info->max_inline = max_t(u64,
 206                                                 info->max_inline,
 207                                                 root->sectorsize);
 208                                 }
 209                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 210                                         info->max_inline);
 211                         }
 212                         break;
 213                 case Opt_alloc_start:
 214                         num = match_strdup(&args[0]);
 215                         if (num) {
 216                                 info->alloc_start = btrfs_parse_size(num);
 217                                 kfree(num);
 218                                 printk(KERN_INFO
 219                                         "btrfs: allocations start at %llu\n",
 220                                         info->alloc_start);
 221                         }
 222                         break;
 223                 case Opt_noacl:
 224                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 225                         break;
 226                 default:
 227                         break;
 228                 }
 229         }
 230         kfree(options);
 231         return 0;
 232 }
 233
 234 /*
 235  * Parse mount options that are required early in the mount process.
 236  *
 237  * All other options will be parsed on much later in the mount process and
 238  * only when we need to allocate a new super block.
 239  */
 240 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 241                 void *holder, char **subvol_name,
 242                 struct btrfs_fs_devices **fs_devices)
 243 {
 244         substring_t args[MAX_OPT_ARGS];
 245         char *opts, *p;
 246         int error = 0;
 247
 248         if (!options)
 249                 goto out;
 250
 251         /*
 252          * strsep changes the string, duplicate it because parse_options
 253          * gets called twice
 254          */
 255         opts = kstrdup(options, GFP_KERNEL);
 256         if (!opts)
 257                 return -ENOMEM;
 258
 259         while ((p = strsep(&opts, ",")) != NULL) {
 260                 int token;
 261                 if (!*p)
 262                         continue;
 263
 264                 token = match_token(p, tokens, args);
 265                 switch (token) {
 266                 case Opt_subvol:
 267                         *subvol_name = match_strdup(&args[0]);
 268                         break;
 269                 case Opt_device:
 270                         error = btrfs_scan_one_device(match_strdup(&args[0]),
 271                                         flags, holder, fs_devices);
 272                         if (error)
 273                                 goto out_free_opts;
 274                         break;
 275                 default:
 276                         break;
 277                 }
 278         }
 279
 280  out_free_opts:
 281         kfree(opts);
 282  out:
 283         /*
 284          * If no subvolume name is specified we use the default one.  Allocate
 285          * a copy of the string "." here so that code later in the
 286          * mount path doesn't care if it's the default volume or another one.
 287          */
 288         if (!*subvol_name) {
 289                 *subvol_name = kstrdup(".", GFP_KERNEL);
 290                 if (!*subvol_name)
 291                         return -ENOMEM;
 292         }
 293         return error;
 294 }
 295
 296 static int btrfs_fill_super(struct super_block *sb,
 297                             struct btrfs_fs_devices *fs_devices,
 298                             void *data, int silent)
 299 {
 300         struct inode *inode;
 301         struct dentry *root_dentry;
 302         struct btrfs_super_block *disk_super;
 303         struct btrfs_root *tree_root;
 304         struct btrfs_inode *bi;
 305         int err;
 306
 307         sb->s_maxbytes = MAX_LFS_FILESIZE;
 308         sb->s_magic = BTRFS_SUPER_MAGIC;
 309         sb->s_op = &btrfs_super_ops;
 310         sb->s_export_op = &btrfs_export_ops;
 311         sb->s_xattr = btrfs_xattr_handlers;
 312         sb->s_time_gran = 1;
 313         sb->s_flags |= MS_POSIXACL;
 314
 315         tree_root = open_ctree(sb, fs_devices, (char *)data);
 316
 317         if (IS_ERR(tree_root)) {
 318                 printk("btrfs: open_ctree failed\n");
 319                 return PTR_ERR(tree_root);
 320         }
 321         sb->s_fs_info = tree_root;
 322         disk_super = &tree_root->fs_info->super_copy;
 323         inode = btrfs_iget_locked(sb, BTRFS_FIRST_FREE_OBJECTID,
 324                                   tree_root->fs_info->fs_root);
 325         bi = BTRFS_I(inode);
 326         bi->location.objectid = inode->i_ino;
 327         bi->location.offset = 0;
 328         bi->root = tree_root->fs_info->fs_root;
 329
 330         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
 331
 332         if (!inode) {
 333                 err = -ENOMEM;
 334                 goto fail_close;
 335         }
 336         if (inode->i_state & I_NEW) {
 337                 btrfs_read_locked_inode(inode);
 338                 unlock_new_inode(inode);
 339         }
 340
 341         root_dentry = d_alloc_root(inode);
 342         if (!root_dentry) {
 343                 iput(inode);
 344                 err = -ENOMEM;
 345                 goto fail_close;
 346         }
 347 #if 0
 348         /* this does the super kobj at the same time */
 349         err = btrfs_sysfs_add_super(tree_root->fs_info);
 350         if (err)
 351                 goto fail_close;
 352 #endif
 353
 354         sb->s_root = root_dentry;
 355
 356         save_mount_options(sb, data);
 357         return 0;
 358
 359 fail_close:
 360         close_ctree(tree_root);
 361         return err;
 362 }
 363
 364 int btrfs_sync_fs(struct super_block *sb, int wait)
 365 {
 366         struct btrfs_trans_handle *trans;
 367         struct btrfs_root *root;
 368         int ret;
 369         root = btrfs_sb(sb);
 370
 371         if (sb->s_flags & MS_RDONLY)
 372                 return 0;
 373
 374         sb->s_dirt = 0;
 375         if (!wait) {
 376                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 377                 return 0;
 378         }
 379
 380         btrfs_start_delalloc_inodes(root);
 381         btrfs_wait_ordered_extents(root, 0);
 382
 383         btrfs_clean_old_snapshots(root);
 384         trans = btrfs_start_transaction(root, 1);
 385         ret = btrfs_commit_transaction(trans, root);
 386         sb->s_dirt = 0;
 387         return ret;
 388 }
 389
 390 static void btrfs_write_super(struct super_block *sb)
 391 {
 392         sb->s_dirt = 0;
 393 }
 394
 395 static int btrfs_test_super(struct super_block *s, void *data)
 396 {
 397         struct btrfs_fs_devices *test_fs_devices = data;
 398         struct btrfs_root *root = btrfs_sb(s);
 399
 400         return root->fs_info->fs_devices == test_fs_devices;
 401 }
 402
 403 /*
 404  * Find a superblock for the given device / mount point.
 405  *
 406  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 407  *        for multiple device setup.  Make sure to keep it in sync.
 408  */
 409 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 410                 const char *dev_name, void *data, struct vfsmount *mnt)
 411 {
 412         char *subvol_name = NULL;
 413         struct block_device *bdev = NULL;
 414         struct super_block *s;
 415         struct dentry *root;
 416         struct btrfs_fs_devices *fs_devices = NULL;
 417         fmode_t mode = FMODE_READ;
 418         int error = 0;
 419
 420         if (!(flags & MS_RDONLY))
 421                 mode |= FMODE_WRITE;
 422
 423         error = btrfs_parse_early_options(data, mode, fs_type,
 424                                           &subvol_name, &fs_devices);
 425         if (error)
 426                 return error;
 427
 428         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 429         if (error)
 430                 goto error_free_subvol_name;
 431
 432         error = btrfs_open_devices(fs_devices, mode, fs_type);
 433         if (error)
 434                 goto error_free_subvol_name;
 435
 436         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 437                 error = -EACCES;
 438                 goto error_close_devices;
 439         }
 440
 441         bdev = fs_devices->latest_bdev;
 442         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
 443         if (IS_ERR(s))
 444                 goto error_s;
 445
 446         if (s->s_root) {
 447                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 448                         up_write(&s->s_umount);
 449                         deactivate_super(s);
 450                         error = -EBUSY;
 451                         goto error_close_devices;
 452                 }
 453
 454                 btrfs_close_devices(fs_devices);
 455         } else {
 456                 char b[BDEVNAME_SIZE];
 457
 458                 s->s_flags = flags;
 459                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 460                 error = btrfs_fill_super(s, fs_devices, data,
 461                                          flags & MS_SILENT ? 1 : 0);
 462                 if (error) {
 463                         up_write(&s->s_umount);
 464                         deactivate_super(s);
 465                         goto error_free_subvol_name;
 466                 }
 467
 468                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 469                 s->s_flags |= MS_ACTIVE;
 470         }
 471
 472         if (!strcmp(subvol_name, "."))
 473                 root = dget(s->s_root);
 474         else {
 475                 mutex_lock(&s->s_root->d_inode->i_mutex);
 476                 root = lookup_one_len(subvol_name, s->s_root,
 477                                       strlen(subvol_name));
 478                 mutex_unlock(&s->s_root->d_inode->i_mutex);
 479
 480                 if (IS_ERR(root)) {
 481                         up_write(&s->s_umount);
 482                         deactivate_super(s);
 483                         error = PTR_ERR(root);
 484                         goto error_free_subvol_name;
 485                 }
 486                 if (!root->d_inode) {
 487                         dput(root);
 488                         up_write(&s->s_umount);
 489                         deactivate_super(s);
 490                         error = -ENXIO;
 491                         goto error_free_subvol_name;
 492                 }
 493         }
 494
 495         mnt->mnt_sb = s;
 496         mnt->mnt_root = root;
 497
 498         kfree(subvol_name);
 499         return 0;
 500
 501 error_s:
 502         error = PTR_ERR(s);
 503 error_close_devices:
 504         btrfs_close_devices(fs_devices);
 505 error_free_subvol_name:
 506         kfree(subvol_name);
 507         return error;
 508 }
 509
 510 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 511 {
 512         struct btrfs_root *root = btrfs_sb(sb);
 513         int ret;
 514
 515         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 516                 return 0;
 517
 518         if (*flags & MS_RDONLY) {
 519                 sb->s_flags |= MS_RDONLY;
 520
 521                 ret =  btrfs_commit_super(root);
 522                 WARN_ON(ret);
 523         } else {
 524                 if (root->fs_info->fs_devices->rw_devices == 0)
 525                         return -EACCES;
 526
 527                 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
 528                         return -EINVAL;
 529
 530                 ret = btrfs_cleanup_reloc_trees(root);
 531                 WARN_ON(ret);
 532
 533                 ret = btrfs_cleanup_fs_roots(root->fs_info);
 534                 WARN_ON(ret);
 535
 536                 sb->s_flags &= ~MS_RDONLY;
 537         }
 538
 539         return 0;
 540 }
 541
 542 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 543 {
 544         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 545         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 546         int bits = dentry->d_sb->s_blocksize_bits;
 547         __be32 *fsid = (__be32 *)root->fs_info->fsid;
 548
 549         buf->f_namelen = BTRFS_NAME_LEN;
 550         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 551         buf->f_bfree = buf->f_blocks -
 552                 (btrfs_super_bytes_used(disk_super) >> bits);
 553         buf->f_bavail = buf->f_bfree;
 554         buf->f_bsize = dentry->d_sb->s_blocksize;
 555         buf->f_type = BTRFS_SUPER_MAGIC;
 556
 557         /* We treat it as constant endianness (it doesn't matter _which_)
 558            because we want the fsid to come out the same whether mounted
 559            on a big-endian or little-endian host */
 560         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 561         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 562         /* Mask in the root object ID too, to disambiguate subvols */
 563         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
 564         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
 565
 566         return 0;
 567 }
 568
 569 static struct file_system_type btrfs_fs_type = {
 570         .owner          = THIS_MODULE,
 571         .name           = "btrfs",
 572         .get_sb         = btrfs_get_sb,
 573         .kill_sb        = kill_anon_super,
 574         .fs_flags       = FS_REQUIRES_DEV,
 575 };
 576
 577 /*
 578  * used by btrfsctl to scan devices when no FS is mounted
 579  */
 580 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 581                                 unsigned long arg)
 582 {
 583         struct btrfs_ioctl_vol_args *vol;
 584         struct btrfs_fs_devices *fs_devices;
 585         int ret = 0;
 586         int len;
 587
 588         if (!capable(CAP_SYS_ADMIN))
 589                 return -EPERM;
 590
 591         vol = kmalloc(sizeof(*vol), GFP_KERNEL);
 592         if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
 593                 ret = -EFAULT;
 594                 goto out;
 595         }
 596         len = strnlen(vol->name, BTRFS_PATH_NAME_MAX);
 597         switch (cmd) {
 598         case BTRFS_IOC_SCAN_DEV:
 599                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
 600                                             &btrfs_fs_type, &fs_devices);
 601                 break;
 602         }
 603 out:
 604         kfree(vol);
 605         return ret;
 606 }
 607
 608 static int btrfs_freeze(struct super_block *sb)
 609 {
 610         struct btrfs_root *root = btrfs_sb(sb);
 611         mutex_lock(&root->fs_info->transaction_kthread_mutex);
 612         mutex_lock(&root->fs_info->cleaner_mutex);
 613         return 0;
 614 }
 615
 616 static int btrfs_unfreeze(struct super_block *sb)
 617 {
 618         struct btrfs_root *root = btrfs_sb(sb);
 619         mutex_unlock(&root->fs_info->cleaner_mutex);
 620         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 621         return 0;
 622 }
 623
 624 static struct super_operations btrfs_super_ops = {
 625         .delete_inode   = btrfs_delete_inode,
 626         .put_super      = btrfs_put_super,
 627         .write_super    = btrfs_write_super,
 628         .sync_fs        = btrfs_sync_fs,
 629         .show_options   = generic_show_options,
 630         .write_inode    = btrfs_write_inode,
 631         .dirty_inode    = btrfs_dirty_inode,
 632         .alloc_inode    = btrfs_alloc_inode,
 633         .destroy_inode  = btrfs_destroy_inode,
 634         .statfs         = btrfs_statfs,
 635         .remount_fs     = btrfs_remount,
 636         .freeze_fs      = btrfs_freeze,
 637         .unfreeze_fs    = btrfs_unfreeze,
 638 };
 639
 640 static const struct file_operations btrfs_ctl_fops = {
 641         .unlocked_ioctl  = btrfs_control_ioctl,
 642         .compat_ioctl = btrfs_control_ioctl,
 643         .owner   = THIS_MODULE,
 644 };
 645
 646 static struct miscdevice btrfs_misc = {
 647         .minor          = MISC_DYNAMIC_MINOR,
 648         .name           = "btrfs-control",
 649         .fops           = &btrfs_ctl_fops
 650 };
 651
 652 static int btrfs_interface_init(void)
 653 {
 654         return misc_register(&btrfs_misc);
 655 }
 656
 657 static void btrfs_interface_exit(void)
 658 {
 659         if (misc_deregister(&btrfs_misc) < 0)
 660                 printk(KERN_INFO "misc_deregister failed for control device");
 661 }
 662
 663 static int __init init_btrfs_fs(void)
 664 {
 665         int err;
 666
 667         err = btrfs_init_sysfs();
 668         if (err)
 669                 return err;
 670
 671         err = btrfs_init_cachep();
 672         if (err)
 673                 goto free_sysfs;
 674
 675         err = extent_io_init();
 676         if (err)
 677                 goto free_cachep;
 678
 679         err = extent_map_init();
 680         if (err)
 681                 goto free_extent_io;
 682
 683         err = btrfs_interface_init();
 684         if (err)
 685                 goto free_extent_map;
 686
 687         err = register_filesystem(&btrfs_fs_type);
 688         if (err)
 689                 goto unregister_ioctl;
 690
 691         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
 692         return 0;
 693
 694 unregister_ioctl:
 695         btrfs_interface_exit();
 696 free_extent_map:
 697         extent_map_exit();
 698 free_extent_io:
 699         extent_io_exit();
 700 free_cachep:
 701         btrfs_destroy_cachep();
 702 free_sysfs:
 703         btrfs_exit_sysfs();
 704         return err;
 705 }
 706
 707 static void __exit exit_btrfs_fs(void)
 708 {
 709         btrfs_destroy_cachep();
 710         extent_map_exit();
 711         extent_io_exit();
 712         btrfs_interface_exit();
 713         unregister_filesystem(&btrfs_fs_type);
 714         btrfs_exit_sysfs();
 715         btrfs_cleanup_fs_uuids();
 716         btrfs_zlib_exit();
 717 }
 718
 719 module_init(init_btrfs_fs)
 720 module_exit(exit_btrfs_fs)
 721
 722 MODULE_LICENSE("GPL");