Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
[linux-3.10.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/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");