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 static struct super_operations btrfs_super_ops;
  56
  57 static void btrfs_put_super(struct super_block *sb)
  58 {
  59         struct btrfs_root *root = btrfs_sb(sb);
  60         int ret;
  61
  62         ret = close_ctree(root);
  63         sb->s_fs_info = NULL;
  64 }
  65
  66 enum {
  67         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
  68         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
  69         Opt_ssd, Opt_thread_pool, Opt_noacl,  Opt_compress, Opt_notreelog,
  70         Opt_ratio, Opt_flushoncommit, 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_notreelog, "notreelog"},
  88         {Opt_flushoncommit, "flushoncommit"},
  89         {Opt_ratio, "metadata_ratio=%d"},
  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                                        (unsigned long long)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                                         (unsigned long long)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                                         (unsigned long long)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                 case Opt_ratio:
 238                         intarg = 0;
 239                         match_int(&args[0], &intarg);
 240                         if (intarg) {
 241                                 info->metadata_ratio = intarg;
 242                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 243                                        info->metadata_ratio);
 244                         }
 245                         break;
 246                 default:
 247                         break;
 248                 }
 249         }
 250         kfree(options);
 251         return 0;
 252 }
 253
 254 /*
 255  * Parse mount options that are required early in the mount process.
 256  *
 257  * All other options will be parsed on much later in the mount process and
 258  * only when we need to allocate a new super block.
 259  */
 260 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 261                 void *holder, char **subvol_name,
 262                 struct btrfs_fs_devices **fs_devices)
 263 {
 264         substring_t args[MAX_OPT_ARGS];
 265         char *opts, *p;
 266         int error = 0;
 267
 268         if (!options)
 269                 goto out;
 270
 271         /*
 272          * strsep changes the string, duplicate it because parse_options
 273          * gets called twice
 274          */
 275         opts = kstrdup(options, GFP_KERNEL);
 276         if (!opts)
 277                 return -ENOMEM;
 278
 279         while ((p = strsep(&opts, ",")) != NULL) {
 280                 int token;
 281                 if (!*p)
 282                         continue;
 283
 284                 token = match_token(p, tokens, args);
 285                 switch (token) {
 286                 case Opt_subvol:
 287                         *subvol_name = match_strdup(&args[0]);
 288                         break;
 289                 case Opt_device:
 290                         error = btrfs_scan_one_device(match_strdup(&args[0]),
 291                                         flags, holder, fs_devices);
 292                         if (error)
 293                                 goto out_free_opts;
 294                         break;
 295                 default:
 296                         break;
 297                 }
 298         }
 299
 300  out_free_opts:
 301         kfree(opts);
 302  out:
 303         /*
 304          * If no subvolume name is specified we use the default one.  Allocate
 305          * a copy of the string "." here so that code later in the
 306          * mount path doesn't care if it's the default volume or another one.
 307          */
 308         if (!*subvol_name) {
 309                 *subvol_name = kstrdup(".", GFP_KERNEL);
 310                 if (!*subvol_name)
 311                         return -ENOMEM;
 312         }
 313         return error;
 314 }
 315
 316 static int btrfs_fill_super(struct super_block *sb,
 317                             struct btrfs_fs_devices *fs_devices,
 318                             void *data, int silent)
 319 {
 320         struct inode *inode;
 321         struct dentry *root_dentry;
 322         struct btrfs_super_block *disk_super;
 323         struct btrfs_root *tree_root;
 324         struct btrfs_key key;
 325         int err;
 326
 327         sb->s_maxbytes = MAX_LFS_FILESIZE;
 328         sb->s_magic = BTRFS_SUPER_MAGIC;
 329         sb->s_op = &btrfs_super_ops;
 330         sb->s_export_op = &btrfs_export_ops;
 331         sb->s_xattr = btrfs_xattr_handlers;
 332         sb->s_time_gran = 1;
 333         sb->s_flags |= MS_POSIXACL;
 334
 335         tree_root = open_ctree(sb, fs_devices, (char *)data);
 336
 337         if (IS_ERR(tree_root)) {
 338                 printk("btrfs: open_ctree failed\n");
 339                 return PTR_ERR(tree_root);
 340         }
 341         sb->s_fs_info = tree_root;
 342         disk_super = &tree_root->fs_info->super_copy;
 343
 344         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 345         key.type = BTRFS_INODE_ITEM_KEY;
 346         key.offset = 0;
 347         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root);
 348         if (IS_ERR(inode)) {
 349                 err = PTR_ERR(inode);
 350                 goto fail_close;
 351         }
 352
 353         root_dentry = d_alloc_root(inode);
 354         if (!root_dentry) {
 355                 iput(inode);
 356                 err = -ENOMEM;
 357                 goto fail_close;
 358         }
 359 #if 0
 360         /* this does the super kobj at the same time */
 361         err = btrfs_sysfs_add_super(tree_root->fs_info);
 362         if (err)
 363                 goto fail_close;
 364 #endif
 365
 366         sb->s_root = root_dentry;
 367
 368         save_mount_options(sb, data);
 369         return 0;
 370
 371 fail_close:
 372         close_ctree(tree_root);
 373         return err;
 374 }
 375
 376 int btrfs_sync_fs(struct super_block *sb, int wait)
 377 {
 378         struct btrfs_trans_handle *trans;
 379         struct btrfs_root *root = btrfs_sb(sb);
 380         int ret;
 381
 382         if (sb->s_flags & MS_RDONLY)
 383                 return 0;
 384
 385         sb->s_dirt = 0;
 386         if (!wait) {
 387                 filemap_flush(root->fs_info->btree_inode->i_mapping);
 388                 return 0;
 389         }
 390
 391         btrfs_start_delalloc_inodes(root);
 392         btrfs_wait_ordered_extents(root, 0);
 393
 394         trans = btrfs_start_transaction(root, 1);
 395         ret = btrfs_commit_transaction(trans, root);
 396         sb->s_dirt = 0;
 397         return ret;
 398 }
 399
 400 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 401 {
 402         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
 403         struct btrfs_fs_info *info = root->fs_info;
 404
 405         if (btrfs_test_opt(root, DEGRADED))
 406                 seq_puts(seq, ",degraded");
 407         if (btrfs_test_opt(root, NODATASUM))
 408                 seq_puts(seq, ",nodatasum");
 409         if (btrfs_test_opt(root, NODATACOW))
 410                 seq_puts(seq, ",nodatacow");
 411         if (btrfs_test_opt(root, NOBARRIER))
 412                 seq_puts(seq, ",nobarrier");
 413         if (info->max_extent != (u64)-1)
 414                 seq_printf(seq, ",max_extent=%llu",
 415                            (unsigned long long)info->max_extent);
 416         if (info->max_inline != 8192 * 1024)
 417                 seq_printf(seq, ",max_inline=%llu",
 418                            (unsigned long long)info->max_inline);
 419         if (info->alloc_start != 0)
 420                 seq_printf(seq, ",alloc_start=%llu",
 421                            (unsigned long long)info->alloc_start);
 422         if (info->thread_pool_size !=  min_t(unsigned long,
 423                                              num_online_cpus() + 2, 8))
 424                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 425         if (btrfs_test_opt(root, COMPRESS))
 426                 seq_puts(seq, ",compress");
 427         if (btrfs_test_opt(root, SSD))
 428                 seq_puts(seq, ",ssd");
 429         if (btrfs_test_opt(root, NOTREELOG))
 430                 seq_puts(seq, ",notreelog");
 431         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 432                 seq_puts(seq, ",flushoncommit");
 433         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 434                 seq_puts(seq, ",noacl");
 435         return 0;
 436 }
 437
 438 static void btrfs_write_super(struct super_block *sb)
 439 {
 440         sb->s_dirt = 0;
 441 }
 442
 443 static int btrfs_test_super(struct super_block *s, void *data)
 444 {
 445         struct btrfs_fs_devices *test_fs_devices = data;
 446         struct btrfs_root *root = btrfs_sb(s);
 447
 448         return root->fs_info->fs_devices == test_fs_devices;
 449 }
 450
 451 /*
 452  * Find a superblock for the given device / mount point.
 453  *
 454  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 455  *        for multiple device setup.  Make sure to keep it in sync.
 456  */
 457 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 458                 const char *dev_name, void *data, struct vfsmount *mnt)
 459 {
 460         char *subvol_name = NULL;
 461         struct block_device *bdev = NULL;
 462         struct super_block *s;
 463         struct dentry *root;
 464         struct btrfs_fs_devices *fs_devices = NULL;
 465         fmode_t mode = FMODE_READ;
 466         int error = 0;
 467
 468         if (!(flags & MS_RDONLY))
 469                 mode |= FMODE_WRITE;
 470
 471         error = btrfs_parse_early_options(data, mode, fs_type,
 472                                           &subvol_name, &fs_devices);
 473         if (error)
 474                 return error;
 475
 476         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 477         if (error)
 478                 goto error_free_subvol_name;
 479
 480         error = btrfs_open_devices(fs_devices, mode, fs_type);
 481         if (error)
 482                 goto error_free_subvol_name;
 483
 484         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
 485                 error = -EACCES;
 486                 goto error_close_devices;
 487         }
 488
 489         bdev = fs_devices->latest_bdev;
 490         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
 491         if (IS_ERR(s))
 492                 goto error_s;
 493
 494         if (s->s_root) {
 495                 if ((flags ^ s->s_flags) & MS_RDONLY) {
 496                         deactivate_locked_super(s);
 497                         error = -EBUSY;
 498                         goto error_close_devices;
 499                 }
 500
 501                 btrfs_close_devices(fs_devices);
 502         } else {
 503                 char b[BDEVNAME_SIZE];
 504
 505                 s->s_flags = flags;
 506                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
 507                 error = btrfs_fill_super(s, fs_devices, data,
 508                                          flags & MS_SILENT ? 1 : 0);
 509                 if (error) {
 510                         deactivate_locked_super(s);
 511                         goto error_free_subvol_name;
 512                 }
 513
 514                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
 515                 s->s_flags |= MS_ACTIVE;
 516         }
 517
 518         if (!strcmp(subvol_name, "."))
 519                 root = dget(s->s_root);
 520         else {
 521                 mutex_lock(&s->s_root->d_inode->i_mutex);
 522                 root = lookup_one_len(subvol_name, s->s_root,
 523                                       strlen(subvol_name));
 524                 mutex_unlock(&s->s_root->d_inode->i_mutex);
 525
 526                 if (IS_ERR(root)) {
 527                         deactivate_locked_super(s);
 528                         error = PTR_ERR(root);
 529                         goto error_free_subvol_name;
 530                 }
 531                 if (!root->d_inode) {
 532                         dput(root);
 533                         deactivate_locked_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                 /* recover relocation */
 579                 ret = btrfs_recover_relocation(root);
 580                 WARN_ON(ret);
 581
 582                 ret = btrfs_cleanup_fs_roots(root->fs_info);
 583                 WARN_ON(ret);
 584
 585                 sb->s_flags &= ~MS_RDONLY;
 586         }
 587
 588         return 0;
 589 }
 590
 591 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 592 {
 593         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
 594         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
 595         int bits = dentry->d_sb->s_blocksize_bits;
 596         __be32 *fsid = (__be32 *)root->fs_info->fsid;
 597
 598         buf->f_namelen = BTRFS_NAME_LEN;
 599         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 600         buf->f_bfree = buf->f_blocks -
 601                 (btrfs_super_bytes_used(disk_super) >> bits);
 602         buf->f_bavail = buf->f_bfree;
 603         buf->f_bsize = dentry->d_sb->s_blocksize;
 604         buf->f_type = BTRFS_SUPER_MAGIC;
 605
 606         /* We treat it as constant endianness (it doesn't matter _which_)
 607            because we want the fsid to come out the same whether mounted
 608            on a big-endian or little-endian host */
 609         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 610         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 611         /* Mask in the root object ID too, to disambiguate subvols */
 612         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
 613         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
 614
 615         return 0;
 616 }
 617
 618 static struct file_system_type btrfs_fs_type = {
 619         .owner          = THIS_MODULE,
 620         .name           = "btrfs",
 621         .get_sb         = btrfs_get_sb,
 622         .kill_sb        = kill_anon_super,
 623         .fs_flags       = FS_REQUIRES_DEV,
 624 };
 625
 626 /*
 627  * used by btrfsctl to scan devices when no FS is mounted
 628  */
 629 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 630                                 unsigned long arg)
 631 {
 632         struct btrfs_ioctl_vol_args *vol;
 633         struct btrfs_fs_devices *fs_devices;
 634         int ret = -ENOTTY;
 635
 636         if (!capable(CAP_SYS_ADMIN))
 637                 return -EPERM;
 638
 639         vol = memdup_user((void __user *)arg, sizeof(*vol));
 640         if (IS_ERR(vol))
 641                 return PTR_ERR(vol);
 642
 643         switch (cmd) {
 644         case BTRFS_IOC_SCAN_DEV:
 645                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
 646                                             &btrfs_fs_type, &fs_devices);
 647                 break;
 648         }
 649
 650         kfree(vol);
 651         return ret;
 652 }
 653
 654 static int btrfs_freeze(struct super_block *sb)
 655 {
 656         struct btrfs_root *root = btrfs_sb(sb);
 657         mutex_lock(&root->fs_info->transaction_kthread_mutex);
 658         mutex_lock(&root->fs_info->cleaner_mutex);
 659         return 0;
 660 }
 661
 662 static int btrfs_unfreeze(struct super_block *sb)
 663 {
 664         struct btrfs_root *root = btrfs_sb(sb);
 665         mutex_unlock(&root->fs_info->cleaner_mutex);
 666         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
 667         return 0;
 668 }
 669
 670 static struct super_operations btrfs_super_ops = {
 671         .delete_inode   = btrfs_delete_inode,
 672         .put_super      = btrfs_put_super,
 673         .write_super    = btrfs_write_super,
 674         .sync_fs        = btrfs_sync_fs,
 675         .show_options   = btrfs_show_options,
 676         .write_inode    = btrfs_write_inode,
 677         .dirty_inode    = btrfs_dirty_inode,
 678         .alloc_inode    = btrfs_alloc_inode,
 679         .destroy_inode  = btrfs_destroy_inode,
 680         .statfs         = btrfs_statfs,
 681         .remount_fs     = btrfs_remount,
 682         .freeze_fs      = btrfs_freeze,
 683         .unfreeze_fs    = btrfs_unfreeze,
 684 };
 685
 686 static const struct file_operations btrfs_ctl_fops = {
 687         .unlocked_ioctl  = btrfs_control_ioctl,
 688         .compat_ioctl = btrfs_control_ioctl,
 689         .owner   = THIS_MODULE,
 690 };
 691
 692 static struct miscdevice btrfs_misc = {
 693         .minor          = MISC_DYNAMIC_MINOR,
 694         .name           = "btrfs-control",
 695         .fops           = &btrfs_ctl_fops
 696 };
 697
 698 static int btrfs_interface_init(void)
 699 {
 700         return misc_register(&btrfs_misc);
 701 }
 702
 703 static void btrfs_interface_exit(void)
 704 {
 705         if (misc_deregister(&btrfs_misc) < 0)
 706                 printk(KERN_INFO "misc_deregister failed for control device");
 707 }
 708
 709 static int __init init_btrfs_fs(void)
 710 {
 711         int err;
 712
 713         err = btrfs_init_sysfs();
 714         if (err)
 715                 return err;
 716
 717         err = btrfs_init_cachep();
 718         if (err)
 719                 goto free_sysfs;
 720
 721         err = extent_io_init();
 722         if (err)
 723                 goto free_cachep;
 724
 725         err = extent_map_init();
 726         if (err)
 727                 goto free_extent_io;
 728
 729         err = btrfs_interface_init();
 730         if (err)
 731                 goto free_extent_map;
 732
 733         err = register_filesystem(&btrfs_fs_type);
 734         if (err)
 735                 goto unregister_ioctl;
 736
 737         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
 738         return 0;
 739
 740 unregister_ioctl:
 741         btrfs_interface_exit();
 742 free_extent_map:
 743         extent_map_exit();
 744 free_extent_io:
 745         extent_io_exit();
 746 free_cachep:
 747         btrfs_destroy_cachep();
 748 free_sysfs:
 749         btrfs_exit_sysfs();
 750         return err;
 751 }
 752
 753 static void __exit exit_btrfs_fs(void)
 754 {
 755         btrfs_destroy_cachep();
 756         extent_map_exit();
 757         extent_io_exit();
 758         btrfs_interface_exit();
 759         unregister_filesystem(&btrfs_fs_type);
 760         btrfs_exit_sysfs();
 761         btrfs_cleanup_fs_uuids();
 762         btrfs_zlib_exit();
 763 }
 764
 765 module_init(init_btrfs_fs)
 766 module_exit(exit_btrfs_fs)
 767
 768 MODULE_LICENSE("GPL");