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/seq_file.h>
  28 #include <linux/string.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/mount.h>
  32 #include <linux/mpage.h>
  33 #include <linux/swap.h>
  34 #include <linux/writeback.h>
  35 #include <linux/statfs.h>
  36 #include <linux/compat.h>
  37 #include <linux/parser.h>
  38 #include <linux/ctype.h>
  39 #include <linux/namei.h>
  40 #include <linux/miscdevice.h>
  41 #include <linux/magic.h>
  42 #include "compat.h"
  43 #include "ctree.h"
  44 #include "disk-io.h"
  45 #include "transaction.h"
  46 #include "btrfs_inode.h"
  47 #include "ioctl.h"
  48 #include "print-tree.h"
  49 #include "xattr.h"
  50 #include "volumes.h"
  51 #include "version.h"
  52 #include "export.h"
  53 #include "compression.h"
  54
  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_notreelog,
  71         Opt_flushoncommit, Opt_err,
  72 };
  73
  74 static match_table_t tokens = {
  75         {Opt_degraded, "degraded"},
  76         {Opt_subvol, "subvol=%s"},
  77         {Opt_device, "device=%s"},
  78         {Opt_nodatasum, "nodatasum"},
  79         {Opt_nodatacow, "nodatacow"},
  80         {Opt_nobarrier, "nobarrier"},
  81         {Opt_max_extent, "max_extent=%s"},
  82         {Opt_max_inline, "max_inline=%s"},
  83         {Opt_alloc_start, "alloc_start=%s"},
  84         {Opt_thread_pool, "thread_pool=%d"},
  85         {Opt_compress, "compress"},
  86         {Opt_ssd, "ssd"},
  87         {Opt_noacl, "noacl"},
  88         {Opt_notreelog, "notreelog"},
  89         {Opt_flushoncommit, "flushoncommit"},
  90         {Opt_err, NULL},
  91 };
  92
  93 u64 btrfs_parse_size(char *str)
  94 {
  95         u64 res;
  96         int mult = 1;
  97         char *end;
  98         char last;
  99
 100         res = simple_strtoul(str, &end, 10);
 101
 102         last = end[0];
 103         if (isalpha(last)) {
 104                 last = tolower(last);
 105                 switch (last) {
 106                 case 'g':
 107                         mult *= 1024;
 108                 case 'm':
 109                         mult *= 1024;
 110                 case 'k':
 111                         mult *= 1024;
 112                 }
 113                 res = res * mult;
 114         }
 115         return res;
 116 }
 117
 118 /*
 119  * Regular mount options parser.  Everything that is needed only when
 120  * reading in a new superblock is parsed here.
 121  */
 122 int btrfs_parse_options(struct btrfs_root *root, char *options)
 123 {
 124         struct btrfs_fs_info *info = root->fs_info;
 125         substring_t args[MAX_OPT_ARGS];
 126         char *p, *num;
 127         int intarg;
 128
 129         if (!options)
 130                 return 0;
 131
 132         /*
 133          * strsep changes the string, duplicate it because parse_options
 134          * gets called twice
 135          */
 136         options = kstrdup(options, GFP_NOFS);
 137         if (!options)
 138                 return -ENOMEM;
 139
 140
 141         while ((p = strsep(&options, ",")) != NULL) {
 142                 int token;
 143                 if (!*p)
 144                         continue;
 145
 146                 token = match_token(p, tokens, args);
 147                 switch (token) {
 148                 case Opt_degraded:
 149                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 150                         btrfs_set_opt(info->mount_opt, DEGRADED);
 151                         break;
 152                 case Opt_subvol:
 153                 case Opt_device:
 154                         /*
 155                          * These are parsed by btrfs_parse_early_options
 156                          * and can be happily ignored here.
 157                          */
 158                         break;
 159                 case Opt_nodatasum:
 160                         printk(KERN_INFO "btrfs: setting nodatacsum\n");
 161                         btrfs_set_opt(info->mount_opt, NODATASUM);
 162                         break;
 163                 case Opt_nodatacow:
 164                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 165                         btrfs_set_opt(info->mount_opt, NODATACOW);
 166                         btrfs_set_opt(info->mount_opt, NODATASUM);
 167                         break;
 168                 case Opt_compress:
 169                         printk(KERN_INFO "btrfs: use compression\n");
 170                         btrfs_set_opt(info->mount_opt, COMPRESS);
 171                         break;
 172                 case Opt_ssd:
 173                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 174                         btrfs_set_opt(info->mount_opt, SSD);
 175                         break;
 176                 case Opt_nobarrier:
 177                         printk(KERN_INFO "btrfs: turning off barriers\n");
 178                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 179                         break;
 180                 case Opt_thread_pool:
 181                         intarg = 0;
 182                         match_int(&args[0], &intarg);
 183                         if (intarg) {
 184                                 info->thread_pool_size = intarg;
 185                                 printk(KERN_INFO "btrfs: thread pool %d\n",
 186                                        info->thread_pool_size);
 187                         }
 188                         break;
 189                 case Opt_max_extent:
 190                         num = match_strdup(&args[0]);
 191                         if (num) {
 192                                 info->max_extent = btrfs_parse_size(num);
 193                                 kfree(num);
 194
 195                                 info->max_extent = max_t(u64,
 196                                         info->max_extent, root->sectorsize);
 197                                 printk(KERN_INFO "btrfs: max_extent at %llu\n",
 198                                        info->max_extent);
 199                         }
 200                         break;
 201                 case Opt_max_inline:
 202                         num = match_strdup(&args[0]);
 203                         if (num) {
 204                                 info->max_inline = btrfs_parse_size(num);
 205                                 kfree(num);
 206
 207                                 if (info->max_inline) {
 208                                         info->max_inline = max_t(u64,
 209                                                 info->max_inline,
 210                                                 root->sectorsize);
 211                                 }
 212                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 213                                         info->max_inline);
 214                         }
 215                         break;
 216                 case Opt_alloc_start:
 217                         num = match_strdup(&args[0]);
 218                         if (num) {
 219                                 info->alloc_start = btrfs_parse_size(num);
 220                                 kfree(num);
 221                                 printk(KERN_INFO
 222                                         "btrfs: allocations start at %llu\n",
 223                                         info->alloc_start);
 224                         }
 225                         break;
 226                 case Opt_noacl:
 227                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 228                         break;
 229                 case Opt_notreelog:
 230                         printk(KERN_INFO "btrfs: disabling tree log\n");
 231                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 232                         break;
 233                 case Opt_flushoncommit:
 234                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 235                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 236                         break;
 237                 default:
 238                         break;
 239                 }
 240         }
 241         kfree(options);
 242         return 0;
 243 }
 244
 245 /*
 246  * Parse mount options that are required early in the mount process.
 247  *
 248  * All other options will be parsed on much later in the mount process and
 249  * only when we need to allocate a new super block.
 250  */
 251 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 252                 void *holder, char **subvol_name,
 253                 struct btrfs_fs_devices **fs_devices)
 254 {
 255         substring_t args[MAX_OPT_ARGS];
 256         char *opts, *p;
 257         int error = 0;
 258
 259         if (!options)
 260                 goto out;
 261
 262         /*
 263          * strsep changes the string, duplicate it because parse_options
 264          * gets called twice
 265          */
 266         opts = kstrdup(options, GFP_KERNEL);
 267         if (!opts)
 268                 return -ENOMEM;
 269
 270         while ((p = strsep(&opts, ",")) != NULL) {
 271                 int token;
 272                 if (!*p)
 273                         continue;
 274
 275                 token = match_token(p, tokens, args);
 276                 switch (token) {
 277                 case Opt_subvol:
 278                         *subvol_name = match_strdup(&args[0]);
 279                         break;
 280                 case Opt_device:
 281                         error = btrfs_scan_one_device(match_strdup(&args[0]),
 282                                         flags, holder, fs_devices);
 283                         if (error)
 284                                 goto out_free_opts;
 285                         break;
 286                 default:
 287                         break;
 288                 }
 289         }
 290
 291  out_free_opts:
 292         kfree(opts);
 293  out:
 294         /*
 295          * If no subvolume name is specified we use the default one.  Allocate
 296          * a copy of the string "." here so that code later in the
 297          * mount path doesn't care if it's the default volume or another one.
 298          */
 299         if (!*subvol_name) {
 300                 *subvol_name = kstrdup(".", GFP_KERNEL);
 301                 if (!*subvol_name)
 302                         return -ENOMEM;
 303         }
 304         return error;
 305 }
 306
 307 static int btrfs_fill_super(struct super_block *sb,
 308                             struct btrfs_fs_devices *fs_devices,
 309                             void *data, int silent)
 310 {
 311         struct inode *inode;
 312         struct dentry *root_dentry;
 313         struct btrfs_super_block *disk_super;
 314         struct btrfs_root *tree_root;
 315         struct btrfs_inode *bi;
 316         int err;
 317
 318         sb->s_maxbytes = MAX_LFS_FILESIZE;
 319         sb->s_magic = BTRFS_SUPER_MAGIC;
 320         sb->s_op = &btrfs_super_ops;
 321         sb->s_export_op = &btrfs_export_ops;
 322         sb->s_xattr = btrfs_xattr_handlers;
 323         sb->s_time_gran = 1;
 324         sb->s_flags |= MS_POSIXACL;
 325
 326         tree_root = open_ctree(sb, fs_devices, (char *)data);
 327
 328         if (IS_ERR(tree_root)) {
 329                 printk("btrfs: open_ctree failed\n");
 330                 return PTR_ERR(tree_root);
 331         }
 332         sb->s_fs_info = tree_root;
 333         disk_super = &tree_root->fs_info->super_copy;
 334         inode = btrfs_iget_locked(sb, BTRFS_FIRST_FREE_OBJECTID,
 335                                   tree_root->fs_info->fs_root);
 336         bi = BTRFS_I(inode);
 337         bi->location.objectid = inode->i_ino;
 338         bi->location.offset = 0;
 339         bi->root = tree_root->fs_info->fs_root;
 340
 341         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
 342
 343         if (!inode) {
 344                 err = -ENOMEM;
 345                 goto fail_close;
 346         }
 347         if (inode->i_state & I_NEW) {
 348                 btrfs_read_locked_inode(inode);
 349                 unlock_new_inode(inode);
 350         }
 351
 352         root_dentry = d_alloc_root(inode);
 353         if (!root_dentry) {
 354                 iput(inode);
 355                 err = -ENOMEM;
 356                 goto fail_close;
 357         }
 358 #if 0
 359         /* this does the super kobj at the same time */
 360         err = btrfs_sysfs_add_super(tree_root->fs_info);
 361         if (err)
 362                 goto fail_close;
 363 #endif
 364
 365         sb->s_root = root_dentry;
 366
 367         save_mount_options(sb, data);
 368         return 0;
 369
 370 fail_close:
 371         close_ctree(tree_root);
 372         return err;
 373 }
 374
 375 int btrfs_sync_fs(struct super_block *sb, int wait)
 376 {
 377         struct btrfs_trans_handle *trans;
 378         struct btrfs_root *root = btrfs_sb(sb);
 379         int ret;
 380
 381         if (sb->s_flags & MS_RDONLY)
 382                 return 0;
 383
 384         sb->s_dirt = 0;
 385         if (!wait) {
 386                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 387                 return 0;
 388         }
 389
 390         btrfs_start_delalloc_inodes(root);
 391         btrfs_wait_ordered_extents(root, 0);
 392
 393         trans = btrfs_start_transaction(root, 1);
 394         ret = btrfs_commit_transaction(trans, root);
 395         sb->s_dirt = 0;
 396         return ret;
 397 }
 398
 399 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 400 {
 401         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 402         struct btrfs_fs_info *info = root->fs_info;
 403
 404         if (btrfs_test_opt(root, DEGRADED))
 405                 seq_puts(seq, ",degraded");
 406         if (btrfs_test_opt(root, NODATASUM))
 407                 seq_puts(seq, ",nodatasum");
 408         if (btrfs_test_opt(root, NODATACOW))
 409                 seq_puts(seq, ",nodatacow");
 410         if (btrfs_test_opt(root, NOBARRIER))
 411                 seq_puts(seq, ",nobarrier");
 412         if (info->max_extent != (u64)-1)
 413                 seq_printf(seq, ",max_extent=%llu", info->max_extent);
 414         if (info->max_inline != 8192 * 1024)
 415                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
 416         if (info->alloc_start != 0)
 417                 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
 418         if (info->thread_pool_size !=  min_t(unsigned long,
 419                                              num_online_cpus() + 2, 8))
 420                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 421         if (btrfs_test_opt(root, COMPRESS))
 422                 seq_puts(seq, ",compress");
 423         if (btrfs_test_opt(root, SSD))
 424                 seq_puts(seq, ",ssd");
 425         if (btrfs_test_opt(root, NOTREELOG))
 426                 seq_puts(seq, ",no-treelog");
 427         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 428                 seq_puts(seq, ",flush-on-commit");
 429         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 430                 seq_puts(seq, ",noacl");
 431         return 0;
 432 }
 433
 434 static void btrfs_write_super(struct super_block *sb)
 435 {
 436         sb->s_dirt = 0;
 437 }
 438
 439 static int btrfs_test_super(struct super_block *s, void *data)
 440 {
 441         struct btrfs_fs_devices *test_fs_devices = data;
 442         struct btrfs_root *root = btrfs_sb(s);
 443
 444         return root->fs_info->fs_devices == test_fs_devices;
 445 }
 446
 447 /*
 448  * Find a superblock for the given device / mount point.
 449  *
 450  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 451  *        for multiple device setup.  Make sure to keep it in sync.
 452  */
 453 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 454                 const char *dev_name, void *data, struct vfsmount *mnt)
 455 {
 456         char *subvol_name = NULL;
 457         struct block_device *bdev = NULL;
 458         struct super_block *s;
 459         struct dentry *root;
 460         struct btrfs_fs_devices *fs_devices = NULL;
 461         fmode_t mode = FMODE_READ;
 462         int error = 0;
 463
 464         if (!(flags & MS_RDONLY))
 465                 mode |= FMODE_WRITE;
 466
 467         error = btrfs_parse_early_options(data, mode, fs_type,
 468                                           &subvol_name, &fs_devices);
 469         if (error)
 470                 return error;
 471
 472         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 473         if (error)
 474                 goto error_free_subvol_name;
 475
 476         error = btrfs_open_devices(fs_devices, mode, fs_type);
 477         if (error)
 478                 goto error_free_subvol_name;
 479
 480         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 481                 error = -EACCES;
 482                 goto error_close_devices;
 483         }
 484
 485         bdev = fs_devices->latest_bdev;
 486         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
 487         if (IS_ERR(s))
 488                 goto error_s;
 489
 490         if (s->s_root) {
 491                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 492                         up_write(&s->s_umount);
 493                         deactivate_super(s);
 494                         error = -EBUSY;
 495                         goto error_close_devices;
 496                 }
 497
 498                 btrfs_close_devices(fs_devices);
 499         } else {
 500                 char b[BDEVNAME_SIZE];
 501
 502                 s->s_flags = flags;
 503                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 504                 error = btrfs_fill_super(s, fs_devices, data,
 505                                          flags & MS_SILENT ? 1 : 0);
 506                 if (error) {
 507                         up_write(&s->s_umount);
 508                         deactivate_super(s);
 509                         goto error_free_subvol_name;
 510                 }
 511
 512                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 513                 s->s_flags |= MS_ACTIVE;
 514         }
 515
 516         if (!strcmp(subvol_name, "."))
 517                 root = dget(s->s_root);
 518         else {
 519                 mutex_lock(&s->s_root->d_inode->i_mutex);
 520                 root = lookup_one_len(subvol_name, s->s_root,
 521                                       strlen(subvol_name));
 522                 mutex_unlock(&s->s_root->d_inode->i_mutex);
 523
 524                 if (IS_ERR(root)) {
 525                         up_write(&s->s_umount);
 526                         deactivate_super(s);
 527                         error = PTR_ERR(root);
 528                         goto error_free_subvol_name;
 529                 }
 530                 if (!root->d_inode) {
 531                         dput(root);
 532                         up_write(&s->s_umount);
 533                         deactivate_super(s);
 534                         error = -ENXIO;
 535                         goto error_free_subvol_name;
 536                 }
 537         }
 538
 539         mnt->mnt_sb = s;
 540         mnt->mnt_root = root;
 541
 542         kfree(subvol_name);
 543         return 0;
 544
 545 error_s:
 546         error = PTR_ERR(s);
 547 error_close_devices:
 548         btrfs_close_devices(fs_devices);
 549 error_free_subvol_name:
 550         kfree(subvol_name);
 551         return error;
 552 }
 553
 554 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 555 {
 556         struct btrfs_root *root = btrfs_sb(sb);
 557         int ret;
 558
 559         ret = btrfs_parse_options(root, data);
 560         if (ret)
 561                 return -EINVAL;
 562
 563         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 564                 return 0;
 565
 566         if (*flags & MS_RDONLY) {
 567                 sb->s_flags |= MS_RDONLY;
 568
 569                 ret =  btrfs_commit_super(root);
 570                 WARN_ON(ret);
 571         } else {
 572                 if (root->fs_info->fs_devices->rw_devices == 0)
 573                         return -EACCES;
 574
 575                 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
 576                         return -EINVAL;
 577
 578                 ret = btrfs_cleanup_reloc_trees(root);
 579                 WARN_ON(ret);
 580
 581                 ret = btrfs_cleanup_fs_roots(root->fs_info);
 582                 WARN_ON(ret);
 583
 584                 sb->s_flags &= ~MS_RDONLY;
 585         }
 586
 587         return 0;
 588 }
 589
 590 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 591 {
 592         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 593         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 594         int bits = dentry->d_sb->s_blocksize_bits;
 595         __be32 *fsid = (__be32 *)root->fs_info->fsid;
 596
 597         buf->f_namelen = BTRFS_NAME_LEN;
 598         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 599         buf->f_bfree = buf->f_blocks -
 600                 (btrfs_super_bytes_used(disk_super) >> bits);
 601         buf->f_bavail = buf->f_bfree;
 602         buf->f_bsize = dentry->d_sb->s_blocksize;
 603         buf->f_type = BTRFS_SUPER_MAGIC;
 604
 605         /* We treat it as constant endianness (it doesn't matter _which_)
 606            because we want the fsid to come out the same whether mounted
 607            on a big-endian or little-endian host */
 608         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 609         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 610         /* Mask in the root object ID too, to disambiguate subvols */
 611         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
 612         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
 613
 614         return 0;
 615 }
 616
 617 static struct file_system_type btrfs_fs_type = {
 618         .owner          = THIS_MODULE,
 619         .name           = "btrfs",
 620         .get_sb         = btrfs_get_sb,
 621         .kill_sb        = kill_anon_super,
 622         .fs_flags       = FS_REQUIRES_DEV,
 623 };
 624
 625 /*
 626  * used by btrfsctl to scan devices when no FS is mounted
 627  */
 628 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 629                                 unsigned long arg)
 630 {
 631         struct btrfs_ioctl_vol_args *vol;
 632         struct btrfs_fs_devices *fs_devices;
 633         int ret = -ENOTTY;
 634
 635         if (!capable(CAP_SYS_ADMIN))
 636                 return -EPERM;
 637
 638         vol = memdup_user((void __user *)arg, sizeof(*vol));
 639         if (IS_ERR(vol))
 640                 return PTR_ERR(vol);
 641
 642         switch (cmd) {
 643         case BTRFS_IOC_SCAN_DEV:
 644                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
 645                                             &btrfs_fs_type, &fs_devices);
 646                 break;
 647         }
 648
 649         kfree(vol);
 650         return ret;
 651 }
 652
 653 static int btrfs_freeze(struct super_block *sb)
 654 {
 655         struct btrfs_root *root = btrfs_sb(sb);
 656         mutex_lock(&root->fs_info->transaction_kthread_mutex);
 657         mutex_lock(&root->fs_info->cleaner_mutex);
 658         return 0;
 659 }
 660
 661 static int btrfs_unfreeze(struct super_block *sb)
 662 {
 663         struct btrfs_root *root = btrfs_sb(sb);
 664         mutex_unlock(&root->fs_info->cleaner_mutex);
 665         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 666         return 0;
 667 }
 668
 669 static struct super_operations btrfs_super_ops = {
 670         .delete_inode   = btrfs_delete_inode,
 671         .put_super      = btrfs_put_super,
 672         .write_super    = btrfs_write_super,
 673         .sync_fs        = btrfs_sync_fs,
 674         .show_options   = btrfs_show_options,
 675         .write_inode    = btrfs_write_inode,
 676         .dirty_inode    = btrfs_dirty_inode,
 677         .alloc_inode    = btrfs_alloc_inode,
 678         .destroy_inode  = btrfs_destroy_inode,
 679         .statfs         = btrfs_statfs,
 680         .remount_fs     = btrfs_remount,
 681         .freeze_fs      = btrfs_freeze,
 682         .unfreeze_fs    = btrfs_unfreeze,
 683 };
 684
 685 static const struct file_operations btrfs_ctl_fops = {
 686         .unlocked_ioctl  = btrfs_control_ioctl,
 687         .compat_ioctl = btrfs_control_ioctl,
 688         .owner   = THIS_MODULE,
 689 };
 690
 691 static struct miscdevice btrfs_misc = {
 692         .minor          = MISC_DYNAMIC_MINOR,
 693         .name           = "btrfs-control",
 694         .fops           = &btrfs_ctl_fops
 695 };
 696
 697 static int btrfs_interface_init(void)
 698 {
 699         return misc_register(&btrfs_misc);
 700 }
 701
 702 static void btrfs_interface_exit(void)
 703 {
 704         if (misc_deregister(&btrfs_misc) < 0)
 705                 printk(KERN_INFO "misc_deregister failed for control device");
 706 }
 707
 708 static int __init init_btrfs_fs(void)
 709 {
 710         int err;
 711
 712         err = btrfs_init_sysfs();
 713         if (err)
 714                 return err;
 715
 716         err = btrfs_init_cachep();
 717         if (err)
 718                 goto free_sysfs;
 719
 720         err = extent_io_init();
 721         if (err)
 722                 goto free_cachep;
 723
 724         err = extent_map_init();
 725         if (err)
 726                 goto free_extent_io;
 727
 728         err = btrfs_interface_init();
 729         if (err)
 730                 goto free_extent_map;
 731
 732         err = register_filesystem(&btrfs_fs_type);
 733         if (err)
 734                 goto unregister_ioctl;
 735
 736         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
 737         return 0;
 738
 739 unregister_ioctl:
 740         btrfs_interface_exit();
 741 free_extent_map:
 742         extent_map_exit();
 743 free_extent_io:
 744         extent_io_exit();
 745 free_cachep:
 746         btrfs_destroy_cachep();
 747 free_sysfs:
 748         btrfs_exit_sysfs();
 749         return err;
 750 }
 751
 752 static void __exit exit_btrfs_fs(void)
 753 {
 754         btrfs_destroy_cachep();
 755         extent_map_exit();
 756         extent_io_exit();
 757         btrfs_interface_exit();
 758         unregister_filesystem(&btrfs_fs_type);
 759         btrfs_exit_sysfs();
 760         btrfs_cleanup_fs_uuids();
 761         btrfs_zlib_exit();
 762 }
 763
 764 module_init(init_btrfs_fs)
 765 module_exit(exit_btrfs_fs)
 766
 767 MODULE_LICENSE("GPL");