8a1ea6e64575a34c507c29cd8c84ec4944885583
[linux-2.6.git] / 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/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/magic.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 static const struct super_operations btrfs_super_ops;
55
56 static void btrfs_put_super(struct super_block *sb)
57 {
58         struct btrfs_root *root = btrfs_sb(sb);
59         int ret;
60
61         ret = close_ctree(root);
62         sb->s_fs_info = NULL;
63 }
64
65 enum {
66         Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
67         Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
68         Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl,
69         Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio,
70         Opt_flushoncommit,
71         Opt_discard, 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_compress_force, "compress-force"},
87         {Opt_ssd, "ssd"},
88         {Opt_ssd_spread, "ssd_spread"},
89         {Opt_nossd, "nossd"},
90         {Opt_noacl, "noacl"},
91         {Opt_notreelog, "notreelog"},
92         {Opt_flushoncommit, "flushoncommit"},
93         {Opt_ratio, "metadata_ratio=%d"},
94         {Opt_discard, "discard"},
95         {Opt_err, NULL},
96 };
97
98 u64 btrfs_parse_size(char *str)
99 {
100         u64 res;
101         int mult = 1;
102         char *end;
103         char last;
104
105         res = simple_strtoul(str, &end, 10);
106
107         last = end[0];
108         if (isalpha(last)) {
109                 last = tolower(last);
110                 switch (last) {
111                 case 'g':
112                         mult *= 1024;
113                 case 'm':
114                         mult *= 1024;
115                 case 'k':
116                         mult *= 1024;
117                 }
118                 res = res * mult;
119         }
120         return res;
121 }
122
123 /*
124  * Regular mount options parser.  Everything that is needed only when
125  * reading in a new superblock is parsed here.
126  */
127 int btrfs_parse_options(struct btrfs_root *root, char *options)
128 {
129         struct btrfs_fs_info *info = root->fs_info;
130         substring_t args[MAX_OPT_ARGS];
131         char *p, *num;
132         int intarg;
133         int ret = 0;
134
135         if (!options)
136                 return 0;
137
138         /*
139          * strsep changes the string, duplicate it because parse_options
140          * gets called twice
141          */
142         options = kstrdup(options, GFP_NOFS);
143         if (!options)
144                 return -ENOMEM;
145
146
147         while ((p = strsep(&options, ",")) != NULL) {
148                 int token;
149                 if (!*p)
150                         continue;
151
152                 token = match_token(p, tokens, args);
153                 switch (token) {
154                 case Opt_degraded:
155                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
156                         btrfs_set_opt(info->mount_opt, DEGRADED);
157                         break;
158                 case Opt_subvol:
159                 case Opt_device:
160                         /*
161                          * These are parsed by btrfs_parse_early_options
162                          * and can be happily ignored here.
163                          */
164                         break;
165                 case Opt_nodatasum:
166                         printk(KERN_INFO "btrfs: setting nodatasum\n");
167                         btrfs_set_opt(info->mount_opt, NODATASUM);
168                         break;
169                 case Opt_nodatacow:
170                         printk(KERN_INFO "btrfs: setting nodatacow\n");
171                         btrfs_set_opt(info->mount_opt, NODATACOW);
172                         btrfs_set_opt(info->mount_opt, NODATASUM);
173                         break;
174                 case Opt_compress:
175                         printk(KERN_INFO "btrfs: use compression\n");
176                         btrfs_set_opt(info->mount_opt, COMPRESS);
177                         break;
178                 case Opt_compress_force:
179                         printk(KERN_INFO "btrfs: forcing compression\n");
180                         btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
181                         btrfs_set_opt(info->mount_opt, COMPRESS);
182                         break;
183                 case Opt_ssd:
184                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
185                         btrfs_set_opt(info->mount_opt, SSD);
186                         break;
187                 case Opt_ssd_spread:
188                         printk(KERN_INFO "btrfs: use spread ssd "
189                                "allocation scheme\n");
190                         btrfs_set_opt(info->mount_opt, SSD);
191                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
192                         break;
193                 case Opt_nossd:
194                         printk(KERN_INFO "btrfs: not using ssd allocation "
195                                "scheme\n");
196                         btrfs_set_opt(info->mount_opt, NOSSD);
197                         btrfs_clear_opt(info->mount_opt, SSD);
198                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
199                         break;
200                 case Opt_nobarrier:
201                         printk(KERN_INFO "btrfs: turning off barriers\n");
202                         btrfs_set_opt(info->mount_opt, NOBARRIER);
203                         break;
204                 case Opt_thread_pool:
205                         intarg = 0;
206                         match_int(&args[0], &intarg);
207                         if (intarg) {
208                                 info->thread_pool_size = intarg;
209                                 printk(KERN_INFO "btrfs: thread pool %d\n",
210                                        info->thread_pool_size);
211                         }
212                         break;
213                 case Opt_max_extent:
214                         num = match_strdup(&args[0]);
215                         if (num) {
216                                 info->max_extent = btrfs_parse_size(num);
217                                 kfree(num);
218
219                                 info->max_extent = max_t(u64,
220                                         info->max_extent, root->sectorsize);
221                                 printk(KERN_INFO "btrfs: max_extent at %llu\n",
222                                        (unsigned long long)info->max_extent);
223                         }
224                         break;
225                 case Opt_max_inline:
226                         num = match_strdup(&args[0]);
227                         if (num) {
228                                 info->max_inline = btrfs_parse_size(num);
229                                 kfree(num);
230
231                                 if (info->max_inline) {
232                                         info->max_inline = max_t(u64,
233                                                 info->max_inline,
234                                                 root->sectorsize);
235                                 }
236                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
237                                         (unsigned long long)info->max_inline);
238                         }
239                         break;
240                 case Opt_alloc_start:
241                         num = match_strdup(&args[0]);
242                         if (num) {
243                                 info->alloc_start = btrfs_parse_size(num);
244                                 kfree(num);
245                                 printk(KERN_INFO
246                                         "btrfs: allocations start at %llu\n",
247                                         (unsigned long long)info->alloc_start);
248                         }
249                         break;
250                 case Opt_noacl:
251                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
252                         break;
253                 case Opt_notreelog:
254                         printk(KERN_INFO "btrfs: disabling tree log\n");
255                         btrfs_set_opt(info->mount_opt, NOTREELOG);
256                         break;
257                 case Opt_flushoncommit:
258                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
259                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
260                         break;
261                 case Opt_ratio:
262                         intarg = 0;
263                         match_int(&args[0], &intarg);
264                         if (intarg) {
265                                 info->metadata_ratio = intarg;
266                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
267                                        info->metadata_ratio);
268                         }
269                         break;
270                 case Opt_discard:
271                         btrfs_set_opt(info->mount_opt, DISCARD);
272                         break;
273                 case Opt_err:
274                         printk(KERN_INFO "btrfs: unrecognized mount option "
275                                "'%s'\n", p);
276                         ret = -EINVAL;
277                         goto out;
278                 default:
279                         break;
280                 }
281         }
282 out:
283         kfree(options);
284         return ret;
285 }
286
287 /*
288  * Parse mount options that are required early in the mount process.
289  *
290  * All other options will be parsed on much later in the mount process and
291  * only when we need to allocate a new super block.
292  */
293 static int btrfs_parse_early_options(const char *options, fmode_t flags,
294                 void *holder, char **subvol_name,
295                 struct btrfs_fs_devices **fs_devices)
296 {
297         substring_t args[MAX_OPT_ARGS];
298         char *opts, *p;
299         int error = 0;
300
301         if (!options)
302                 goto out;
303
304         /*
305          * strsep changes the string, duplicate it because parse_options
306          * gets called twice
307          */
308         opts = kstrdup(options, GFP_KERNEL);
309         if (!opts)
310                 return -ENOMEM;
311
312         while ((p = strsep(&opts, ",")) != NULL) {
313                 int token;
314                 if (!*p)
315                         continue;
316
317                 token = match_token(p, tokens, args);
318                 switch (token) {
319                 case Opt_subvol:
320                         *subvol_name = match_strdup(&args[0]);
321                         break;
322                 case Opt_device:
323                         error = btrfs_scan_one_device(match_strdup(&args[0]),
324                                         flags, holder, fs_devices);
325                         if (error)
326                                 goto out_free_opts;
327                         break;
328                 default:
329                         break;
330                 }
331         }
332
333  out_free_opts:
334         kfree(opts);
335  out:
336         /*
337          * If no subvolume name is specified we use the default one.  Allocate
338          * a copy of the string "." here so that code later in the
339          * mount path doesn't care if it's the default volume or another one.
340          */
341         if (!*subvol_name) {
342                 *subvol_name = kstrdup(".", GFP_KERNEL);
343                 if (!*subvol_name)
344                         return -ENOMEM;
345         }
346         return error;
347 }
348
349 static int btrfs_fill_super(struct super_block *sb,
350                             struct btrfs_fs_devices *fs_devices,
351                             void *data, int silent)
352 {
353         struct inode *inode;
354         struct dentry *root_dentry;
355         struct btrfs_super_block *disk_super;
356         struct btrfs_root *tree_root;
357         struct btrfs_key key;
358         int err;
359
360         sb->s_maxbytes = MAX_LFS_FILESIZE;
361         sb->s_magic = BTRFS_SUPER_MAGIC;
362         sb->s_op = &btrfs_super_ops;
363         sb->s_export_op = &btrfs_export_ops;
364         sb->s_xattr = btrfs_xattr_handlers;
365         sb->s_time_gran = 1;
366 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
367         sb->s_flags |= MS_POSIXACL;
368 #endif
369
370         tree_root = open_ctree(sb, fs_devices, (char *)data);
371
372         if (IS_ERR(tree_root)) {
373                 printk("btrfs: open_ctree failed\n");
374                 return PTR_ERR(tree_root);
375         }
376         sb->s_fs_info = tree_root;
377         disk_super = &tree_root->fs_info->super_copy;
378
379         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
380         key.type = BTRFS_INODE_ITEM_KEY;
381         key.offset = 0;
382         inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root);
383         if (IS_ERR(inode)) {
384                 err = PTR_ERR(inode);
385                 goto fail_close;
386         }
387
388         root_dentry = d_alloc_root(inode);
389         if (!root_dentry) {
390                 iput(inode);
391                 err = -ENOMEM;
392                 goto fail_close;
393         }
394 #if 0
395         /* this does the super kobj at the same time */
396         err = btrfs_sysfs_add_super(tree_root->fs_info);
397         if (err)
398                 goto fail_close;
399 #endif
400
401         sb->s_root = root_dentry;
402
403         save_mount_options(sb, data);
404         return 0;
405
406 fail_close:
407         close_ctree(tree_root);
408         return err;
409 }
410
411 int btrfs_sync_fs(struct super_block *sb, int wait)
412 {
413         struct btrfs_trans_handle *trans;
414         struct btrfs_root *root = btrfs_sb(sb);
415         int ret;
416
417         if (!wait) {
418                 filemap_flush(root->fs_info->btree_inode->i_mapping);
419                 return 0;
420         }
421
422         btrfs_start_delalloc_inodes(root, 0);
423         btrfs_wait_ordered_extents(root, 0, 0);
424
425         trans = btrfs_start_transaction(root, 1);
426         ret = btrfs_commit_transaction(trans, root);
427         return ret;
428 }
429
430 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
431 {
432         struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
433         struct btrfs_fs_info *info = root->fs_info;
434
435         if (btrfs_test_opt(root, DEGRADED))
436                 seq_puts(seq, ",degraded");
437         if (btrfs_test_opt(root, NODATASUM))
438                 seq_puts(seq, ",nodatasum");
439         if (btrfs_test_opt(root, NODATACOW))
440                 seq_puts(seq, ",nodatacow");
441         if (btrfs_test_opt(root, NOBARRIER))
442                 seq_puts(seq, ",nobarrier");
443         if (info->max_extent != (u64)-1)
444                 seq_printf(seq, ",max_extent=%llu",
445                            (unsigned long long)info->max_extent);
446         if (info->max_inline != 8192 * 1024)
447                 seq_printf(seq, ",max_inline=%llu",
448                            (unsigned long long)info->max_inline);
449         if (info->alloc_start != 0)
450                 seq_printf(seq, ",alloc_start=%llu",
451                            (unsigned long long)info->alloc_start);
452         if (info->thread_pool_size !=  min_t(unsigned long,
453                                              num_online_cpus() + 2, 8))
454                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
455         if (btrfs_test_opt(root, COMPRESS))
456                 seq_puts(seq, ",compress");
457         if (btrfs_test_opt(root, NOSSD))
458                 seq_puts(seq, ",nossd");
459         if (btrfs_test_opt(root, SSD_SPREAD))
460                 seq_puts(seq, ",ssd_spread");
461         else if (btrfs_test_opt(root, SSD))
462                 seq_puts(seq, ",ssd");
463         if (btrfs_test_opt(root, NOTREELOG))
464                 seq_puts(seq, ",notreelog");
465         if (btrfs_test_opt(root, FLUSHONCOMMIT))
466                 seq_puts(seq, ",flushoncommit");
467         if (btrfs_test_opt(root, DISCARD))
468                 seq_puts(seq, ",discard");
469         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
470                 seq_puts(seq, ",noacl");
471         return 0;
472 }
473
474 static int btrfs_test_super(struct super_block *s, void *data)
475 {
476         struct btrfs_fs_devices *test_fs_devices = data;
477         struct btrfs_root *root = btrfs_sb(s);
478
479         return root->fs_info->fs_devices == test_fs_devices;
480 }
481
482 /*
483  * Find a superblock for the given device / mount point.
484  *
485  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
486  *        for multiple device setup.  Make sure to keep it in sync.
487  */
488 static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
489                 const char *dev_name, void *data, struct vfsmount *mnt)
490 {
491         char *subvol_name = NULL;
492         struct block_device *bdev = NULL;
493         struct super_block *s;
494         struct dentry *root;
495         struct btrfs_fs_devices *fs_devices = NULL;
496         fmode_t mode = FMODE_READ;
497         int error = 0;
498
499         if (!(flags & MS_RDONLY))
500                 mode |= FMODE_WRITE;
501
502         error = btrfs_parse_early_options(data, mode, fs_type,
503                                           &subvol_name, &fs_devices);
504         if (error)
505                 return error;
506
507         error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
508         if (error)
509                 goto error_free_subvol_name;
510
511         error = btrfs_open_devices(fs_devices, mode, fs_type);
512         if (error)
513                 goto error_free_subvol_name;
514
515         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
516                 error = -EACCES;
517                 goto error_close_devices;
518         }
519
520         bdev = fs_devices->latest_bdev;
521         s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
522         if (IS_ERR(s))
523                 goto error_s;
524
525         if (s->s_root) {
526                 if ((flags ^ s->s_flags) & MS_RDONLY) {
527                         deactivate_locked_super(s);
528                         error = -EBUSY;
529                         goto error_close_devices;
530                 }
531
532                 btrfs_close_devices(fs_devices);
533         } else {
534                 char b[BDEVNAME_SIZE];
535
536                 s->s_flags = flags;
537                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
538                 error = btrfs_fill_super(s, fs_devices, data,
539                                          flags & MS_SILENT ? 1 : 0);
540                 if (error) {
541                         deactivate_locked_super(s);
542                         goto error_free_subvol_name;
543                 }
544
545                 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
546                 s->s_flags |= MS_ACTIVE;
547         }
548
549         if (!strcmp(subvol_name, "."))
550                 root = dget(s->s_root);
551         else {
552                 mutex_lock(&s->s_root->d_inode->i_mutex);
553                 root = lookup_one_len(subvol_name, s->s_root,
554                                       strlen(subvol_name));
555                 mutex_unlock(&s->s_root->d_inode->i_mutex);
556
557                 if (IS_ERR(root)) {
558                         deactivate_locked_super(s);
559                         error = PTR_ERR(root);
560                         goto error_free_subvol_name;
561                 }
562                 if (!root->d_inode) {
563                         dput(root);
564                         deactivate_locked_super(s);
565                         error = -ENXIO;
566                         goto error_free_subvol_name;
567                 }
568         }
569
570         mnt->mnt_sb = s;
571         mnt->mnt_root = root;
572
573         kfree(subvol_name);
574         return 0;
575
576 error_s:
577         error = PTR_ERR(s);
578 error_close_devices:
579         btrfs_close_devices(fs_devices);
580 error_free_subvol_name:
581         kfree(subvol_name);
582         return error;
583 }
584
585 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
586 {
587         struct btrfs_root *root = btrfs_sb(sb);
588         int ret;
589
590         ret = btrfs_parse_options(root, data);
591         if (ret)
592                 return -EINVAL;
593
594         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
595                 return 0;
596
597         if (*flags & MS_RDONLY) {
598                 sb->s_flags |= MS_RDONLY;
599
600                 ret =  btrfs_commit_super(root);
601                 WARN_ON(ret);
602         } else {
603                 if (root->fs_info->fs_devices->rw_devices == 0)
604                         return -EACCES;
605
606                 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
607                         return -EINVAL;
608
609                 /* recover relocation */
610                 ret = btrfs_recover_relocation(root);
611                 WARN_ON(ret);
612
613                 ret = btrfs_cleanup_fs_roots(root->fs_info);
614                 WARN_ON(ret);
615
616                 sb->s_flags &= ~MS_RDONLY;
617         }
618
619         return 0;
620 }
621
622 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
623 {
624         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
625         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
626         int bits = dentry->d_sb->s_blocksize_bits;
627         __be32 *fsid = (__be32 *)root->fs_info->fsid;
628
629         buf->f_namelen = BTRFS_NAME_LEN;
630         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
631         buf->f_bfree = buf->f_blocks -
632                 (btrfs_super_bytes_used(disk_super) >> bits);
633         buf->f_bavail = buf->f_bfree;
634         buf->f_bsize = dentry->d_sb->s_blocksize;
635         buf->f_type = BTRFS_SUPER_MAGIC;
636
637         /* We treat it as constant endianness (it doesn't matter _which_)
638            because we want the fsid to come out the same whether mounted
639            on a big-endian or little-endian host */
640         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
641         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
642         /* Mask in the root object ID too, to disambiguate subvols */
643         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
644         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
645
646         return 0;
647 }
648
649 static struct file_system_type btrfs_fs_type = {
650         .owner          = THIS_MODULE,
651         .name           = "btrfs",
652         .get_sb         = btrfs_get_sb,
653         .kill_sb        = kill_anon_super,
654         .fs_flags       = FS_REQUIRES_DEV,
655 };
656
657 /*
658  * used by btrfsctl to scan devices when no FS is mounted
659  */
660 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
661                                 unsigned long arg)
662 {
663         struct btrfs_ioctl_vol_args *vol;
664         struct btrfs_fs_devices *fs_devices;
665         int ret = -ENOTTY;
666
667         if (!capable(CAP_SYS_ADMIN))
668                 return -EPERM;
669
670         vol = memdup_user((void __user *)arg, sizeof(*vol));
671         if (IS_ERR(vol))
672                 return PTR_ERR(vol);
673
674         switch (cmd) {
675         case BTRFS_IOC_SCAN_DEV:
676                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
677                                             &btrfs_fs_type, &fs_devices);
678                 break;
679         }
680
681         kfree(vol);
682         return ret;
683 }
684
685 static int btrfs_freeze(struct super_block *sb)
686 {
687         struct btrfs_root *root = btrfs_sb(sb);
688         mutex_lock(&root->fs_info->transaction_kthread_mutex);
689         mutex_lock(&root->fs_info->cleaner_mutex);
690         return 0;
691 }
692
693 static int btrfs_unfreeze(struct super_block *sb)
694 {
695         struct btrfs_root *root = btrfs_sb(sb);
696         mutex_unlock(&root->fs_info->cleaner_mutex);
697         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
698         return 0;
699 }
700
701 static const struct super_operations btrfs_super_ops = {
702         .drop_inode     = btrfs_drop_inode,
703         .delete_inode   = btrfs_delete_inode,
704         .put_super      = btrfs_put_super,
705         .sync_fs        = btrfs_sync_fs,
706         .show_options   = btrfs_show_options,
707         .write_inode    = btrfs_write_inode,
708         .dirty_inode    = btrfs_dirty_inode,
709         .alloc_inode    = btrfs_alloc_inode,
710         .destroy_inode  = btrfs_destroy_inode,
711         .statfs         = btrfs_statfs,
712         .remount_fs     = btrfs_remount,
713         .freeze_fs      = btrfs_freeze,
714         .unfreeze_fs    = btrfs_unfreeze,
715 };
716
717 static const struct file_operations btrfs_ctl_fops = {
718         .unlocked_ioctl  = btrfs_control_ioctl,
719         .compat_ioctl = btrfs_control_ioctl,
720         .owner   = THIS_MODULE,
721 };
722
723 static struct miscdevice btrfs_misc = {
724         .minor          = MISC_DYNAMIC_MINOR,
725         .name           = "btrfs-control",
726         .fops           = &btrfs_ctl_fops
727 };
728
729 static int btrfs_interface_init(void)
730 {
731         return misc_register(&btrfs_misc);
732 }
733
734 static void btrfs_interface_exit(void)
735 {
736         if (misc_deregister(&btrfs_misc) < 0)
737                 printk(KERN_INFO "misc_deregister failed for control device");
738 }
739
740 static int __init init_btrfs_fs(void)
741 {
742         int err;
743
744         err = btrfs_init_sysfs();
745         if (err)
746                 return err;
747
748         err = btrfs_init_cachep();
749         if (err)
750                 goto free_sysfs;
751
752         err = extent_io_init();
753         if (err)
754                 goto free_cachep;
755
756         err = extent_map_init();
757         if (err)
758                 goto free_extent_io;
759
760         err = btrfs_interface_init();
761         if (err)
762                 goto free_extent_map;
763
764         err = register_filesystem(&btrfs_fs_type);
765         if (err)
766                 goto unregister_ioctl;
767
768         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
769         return 0;
770
771 unregister_ioctl:
772         btrfs_interface_exit();
773 free_extent_map:
774         extent_map_exit();
775 free_extent_io:
776         extent_io_exit();
777 free_cachep:
778         btrfs_destroy_cachep();
779 free_sysfs:
780         btrfs_exit_sysfs();
781         return err;
782 }
783
784 static void __exit exit_btrfs_fs(void)
785 {
786         btrfs_destroy_cachep();
787         extent_map_exit();
788         extent_io_exit();
789         btrfs_interface_exit();
790         unregister_filesystem(&btrfs_fs_type);
791         btrfs_exit_sysfs();
792         btrfs_cleanup_fs_uuids();
793         btrfs_zlib_exit();
794 }
795
796 module_init(init_btrfs_fs)
797 module_exit(exit_btrfs_fs)
798
799 MODULE_LICENSE("GPL");