3ce97b217cbeae21ef23e57fe2a605ed11572af1
[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 <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include "compat.h"
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "ioctl.h"
51 #include "print-tree.h"
52 #include "xattr.h"
53 #include "volumes.h"
54 #include "version.h"
55 #include "export.h"
56 #include "compression.h"
57
58 #define CREATE_TRACE_POINTS
59 #include <trace/events/btrfs.h>
60
61 static const struct super_operations btrfs_super_ops;
62 static struct file_system_type btrfs_fs_type;
63
64 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
65                                       char nbuf[16])
66 {
67         char *errstr = NULL;
68
69         switch (errno) {
70         case -EIO:
71                 errstr = "IO failure";
72                 break;
73         case -ENOMEM:
74                 errstr = "Out of memory";
75                 break;
76         case -EROFS:
77                 errstr = "Readonly filesystem";
78                 break;
79         default:
80                 if (nbuf) {
81                         if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
82                                 errstr = nbuf;
83                 }
84                 break;
85         }
86
87         return errstr;
88 }
89
90 static void __save_error_info(struct btrfs_fs_info *fs_info)
91 {
92         /*
93          * today we only save the error info into ram.  Long term we'll
94          * also send it down to the disk
95          */
96         fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
97 }
98
99 /* NOTE:
100  *      We move write_super stuff at umount in order to avoid deadlock
101  *      for umount hold all lock.
102  */
103 static void save_error_info(struct btrfs_fs_info *fs_info)
104 {
105         __save_error_info(fs_info);
106 }
107
108 /* btrfs handle error by forcing the filesystem readonly */
109 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
110 {
111         struct super_block *sb = fs_info->sb;
112
113         if (sb->s_flags & MS_RDONLY)
114                 return;
115
116         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
117                 sb->s_flags |= MS_RDONLY;
118                 printk(KERN_INFO "btrfs is forced readonly\n");
119         }
120 }
121
122 /*
123  * __btrfs_std_error decodes expected errors from the caller and
124  * invokes the approciate error response.
125  */
126 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
127                      unsigned int line, int errno)
128 {
129         struct super_block *sb = fs_info->sb;
130         char nbuf[16];
131         const char *errstr;
132
133         /*
134          * Special case: if the error is EROFS, and we're already
135          * under MS_RDONLY, then it is safe here.
136          */
137         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
138                 return;
139
140         errstr = btrfs_decode_error(fs_info, errno, nbuf);
141         printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
142                 sb->s_id, function, line, errstr);
143         save_error_info(fs_info);
144
145         btrfs_handle_error(fs_info);
146 }
147
148 static void btrfs_put_super(struct super_block *sb)
149 {
150         (void)close_ctree(btrfs_sb(sb)->tree_root);
151         /* FIXME: need to fix VFS to return error? */
152         /* AV: return it _where_?  ->put_super() can be triggered by any number
153          * of async events, up to and including delivery of SIGKILL to the
154          * last process that kept it busy.  Or segfault in the aforementioned
155          * process...  Whom would you report that to?
156          */
157 }
158
159 enum {
160         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
161         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
162         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
163         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
164         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
165         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
166         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
167         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
168         Opt_check_integrity, Opt_check_integrity_including_extent_data,
169         Opt_check_integrity_print_mask,
170         Opt_err,
171 };
172
173 static match_table_t tokens = {
174         {Opt_degraded, "degraded"},
175         {Opt_subvol, "subvol=%s"},
176         {Opt_subvolid, "subvolid=%d"},
177         {Opt_device, "device=%s"},
178         {Opt_nodatasum, "nodatasum"},
179         {Opt_nodatacow, "nodatacow"},
180         {Opt_nobarrier, "nobarrier"},
181         {Opt_max_inline, "max_inline=%s"},
182         {Opt_alloc_start, "alloc_start=%s"},
183         {Opt_thread_pool, "thread_pool=%d"},
184         {Opt_compress, "compress"},
185         {Opt_compress_type, "compress=%s"},
186         {Opt_compress_force, "compress-force"},
187         {Opt_compress_force_type, "compress-force=%s"},
188         {Opt_ssd, "ssd"},
189         {Opt_ssd_spread, "ssd_spread"},
190         {Opt_nossd, "nossd"},
191         {Opt_noacl, "noacl"},
192         {Opt_notreelog, "notreelog"},
193         {Opt_flushoncommit, "flushoncommit"},
194         {Opt_ratio, "metadata_ratio=%d"},
195         {Opt_discard, "discard"},
196         {Opt_space_cache, "space_cache"},
197         {Opt_clear_cache, "clear_cache"},
198         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
199         {Opt_enospc_debug, "enospc_debug"},
200         {Opt_subvolrootid, "subvolrootid=%d"},
201         {Opt_defrag, "autodefrag"},
202         {Opt_inode_cache, "inode_cache"},
203         {Opt_no_space_cache, "nospace_cache"},
204         {Opt_recovery, "recovery"},
205         {Opt_skip_balance, "skip_balance"},
206         {Opt_check_integrity, "check_int"},
207         {Opt_check_integrity_including_extent_data, "check_int_data"},
208         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
209         {Opt_err, NULL},
210 };
211
212 /*
213  * Regular mount options parser.  Everything that is needed only when
214  * reading in a new superblock is parsed here.
215  */
216 int btrfs_parse_options(struct btrfs_root *root, char *options)
217 {
218         struct btrfs_fs_info *info = root->fs_info;
219         substring_t args[MAX_OPT_ARGS];
220         char *p, *num, *orig = NULL;
221         u64 cache_gen;
222         int intarg;
223         int ret = 0;
224         char *compress_type;
225         bool compress_force = false;
226
227         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
228         if (cache_gen)
229                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
230
231         if (!options)
232                 goto out;
233
234         /*
235          * strsep changes the string, duplicate it because parse_options
236          * gets called twice
237          */
238         options = kstrdup(options, GFP_NOFS);
239         if (!options)
240                 return -ENOMEM;
241
242         orig = options;
243
244         while ((p = strsep(&options, ",")) != NULL) {
245                 int token;
246                 if (!*p)
247                         continue;
248
249                 token = match_token(p, tokens, args);
250                 switch (token) {
251                 case Opt_degraded:
252                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
253                         btrfs_set_opt(info->mount_opt, DEGRADED);
254                         break;
255                 case Opt_subvol:
256                 case Opt_subvolid:
257                 case Opt_subvolrootid:
258                 case Opt_device:
259                         /*
260                          * These are parsed by btrfs_parse_early_options
261                          * and can be happily ignored here.
262                          */
263                         break;
264                 case Opt_nodatasum:
265                         printk(KERN_INFO "btrfs: setting nodatasum\n");
266                         btrfs_set_opt(info->mount_opt, NODATASUM);
267                         break;
268                 case Opt_nodatacow:
269                         printk(KERN_INFO "btrfs: setting nodatacow\n");
270                         btrfs_set_opt(info->mount_opt, NODATACOW);
271                         btrfs_set_opt(info->mount_opt, NODATASUM);
272                         break;
273                 case Opt_compress_force:
274                 case Opt_compress_force_type:
275                         compress_force = true;
276                 case Opt_compress:
277                 case Opt_compress_type:
278                         if (token == Opt_compress ||
279                             token == Opt_compress_force ||
280                             strcmp(args[0].from, "zlib") == 0) {
281                                 compress_type = "zlib";
282                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
283                         } else if (strcmp(args[0].from, "lzo") == 0) {
284                                 compress_type = "lzo";
285                                 info->compress_type = BTRFS_COMPRESS_LZO;
286                         } else {
287                                 ret = -EINVAL;
288                                 goto out;
289                         }
290
291                         btrfs_set_opt(info->mount_opt, COMPRESS);
292                         if (compress_force) {
293                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
294                                 pr_info("btrfs: force %s compression\n",
295                                         compress_type);
296                         } else
297                                 pr_info("btrfs: use %s compression\n",
298                                         compress_type);
299                         break;
300                 case Opt_ssd:
301                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
302                         btrfs_set_opt(info->mount_opt, SSD);
303                         break;
304                 case Opt_ssd_spread:
305                         printk(KERN_INFO "btrfs: use spread ssd "
306                                "allocation scheme\n");
307                         btrfs_set_opt(info->mount_opt, SSD);
308                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
309                         break;
310                 case Opt_nossd:
311                         printk(KERN_INFO "btrfs: not using ssd allocation "
312                                "scheme\n");
313                         btrfs_set_opt(info->mount_opt, NOSSD);
314                         btrfs_clear_opt(info->mount_opt, SSD);
315                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
316                         break;
317                 case Opt_nobarrier:
318                         printk(KERN_INFO "btrfs: turning off barriers\n");
319                         btrfs_set_opt(info->mount_opt, NOBARRIER);
320                         break;
321                 case Opt_thread_pool:
322                         intarg = 0;
323                         match_int(&args[0], &intarg);
324                         if (intarg) {
325                                 info->thread_pool_size = intarg;
326                                 printk(KERN_INFO "btrfs: thread pool %d\n",
327                                        info->thread_pool_size);
328                         }
329                         break;
330                 case Opt_max_inline:
331                         num = match_strdup(&args[0]);
332                         if (num) {
333                                 info->max_inline = memparse(num, NULL);
334                                 kfree(num);
335
336                                 if (info->max_inline) {
337                                         info->max_inline = max_t(u64,
338                                                 info->max_inline,
339                                                 root->sectorsize);
340                                 }
341                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
342                                         (unsigned long long)info->max_inline);
343                         }
344                         break;
345                 case Opt_alloc_start:
346                         num = match_strdup(&args[0]);
347                         if (num) {
348                                 info->alloc_start = memparse(num, NULL);
349                                 kfree(num);
350                                 printk(KERN_INFO
351                                         "btrfs: allocations start at %llu\n",
352                                         (unsigned long long)info->alloc_start);
353                         }
354                         break;
355                 case Opt_noacl:
356                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
357                         break;
358                 case Opt_notreelog:
359                         printk(KERN_INFO "btrfs: disabling tree log\n");
360                         btrfs_set_opt(info->mount_opt, NOTREELOG);
361                         break;
362                 case Opt_flushoncommit:
363                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
364                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
365                         break;
366                 case Opt_ratio:
367                         intarg = 0;
368                         match_int(&args[0], &intarg);
369                         if (intarg) {
370                                 info->metadata_ratio = intarg;
371                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
372                                        info->metadata_ratio);
373                         }
374                         break;
375                 case Opt_discard:
376                         btrfs_set_opt(info->mount_opt, DISCARD);
377                         break;
378                 case Opt_space_cache:
379                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
380                         break;
381                 case Opt_no_space_cache:
382                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
383                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
384                         break;
385                 case Opt_inode_cache:
386                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
387                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
388                         break;
389                 case Opt_clear_cache:
390                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
391                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
392                         break;
393                 case Opt_user_subvol_rm_allowed:
394                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
395                         break;
396                 case Opt_enospc_debug:
397                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
398                         break;
399                 case Opt_defrag:
400                         printk(KERN_INFO "btrfs: enabling auto defrag");
401                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
402                         break;
403                 case Opt_recovery:
404                         printk(KERN_INFO "btrfs: enabling auto recovery");
405                         btrfs_set_opt(info->mount_opt, RECOVERY);
406                         break;
407                 case Opt_skip_balance:
408                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
409                         break;
410 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
411                 case Opt_check_integrity_including_extent_data:
412                         printk(KERN_INFO "btrfs: enabling check integrity"
413                                " including extent data\n");
414                         btrfs_set_opt(info->mount_opt,
415                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
416                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
417                         break;
418                 case Opt_check_integrity:
419                         printk(KERN_INFO "btrfs: enabling check integrity\n");
420                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
421                         break;
422                 case Opt_check_integrity_print_mask:
423                         intarg = 0;
424                         match_int(&args[0], &intarg);
425                         if (intarg) {
426                                 info->check_integrity_print_mask = intarg;
427                                 printk(KERN_INFO "btrfs:"
428                                        " check_integrity_print_mask 0x%x\n",
429                                        info->check_integrity_print_mask);
430                         }
431                         break;
432 #else
433                 case Opt_check_integrity_including_extent_data:
434                 case Opt_check_integrity:
435                 case Opt_check_integrity_print_mask:
436                         printk(KERN_ERR "btrfs: support for check_integrity*"
437                                " not compiled in!\n");
438                         ret = -EINVAL;
439                         goto out;
440 #endif
441                 case Opt_err:
442                         printk(KERN_INFO "btrfs: unrecognized mount option "
443                                "'%s'\n", p);
444                         ret = -EINVAL;
445                         goto out;
446                 default:
447                         break;
448                 }
449         }
450 out:
451         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
452                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
453         kfree(orig);
454         return ret;
455 }
456
457 /*
458  * Parse mount options that are required early in the mount process.
459  *
460  * All other options will be parsed on much later in the mount process and
461  * only when we need to allocate a new super block.
462  */
463 static int btrfs_parse_early_options(const char *options, fmode_t flags,
464                 void *holder, char **subvol_name, u64 *subvol_objectid,
465                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
466 {
467         substring_t args[MAX_OPT_ARGS];
468         char *device_name, *opts, *orig, *p;
469         int error = 0;
470         int intarg;
471
472         if (!options)
473                 return 0;
474
475         /*
476          * strsep changes the string, duplicate it because parse_options
477          * gets called twice
478          */
479         opts = kstrdup(options, GFP_KERNEL);
480         if (!opts)
481                 return -ENOMEM;
482         orig = opts;
483
484         while ((p = strsep(&opts, ",")) != NULL) {
485                 int token;
486                 if (!*p)
487                         continue;
488
489                 token = match_token(p, tokens, args);
490                 switch (token) {
491                 case Opt_subvol:
492                         kfree(*subvol_name);
493                         *subvol_name = match_strdup(&args[0]);
494                         break;
495                 case Opt_subvolid:
496                         intarg = 0;
497                         error = match_int(&args[0], &intarg);
498                         if (!error) {
499                                 /* we want the original fs_tree */
500                                 if (!intarg)
501                                         *subvol_objectid =
502                                                 BTRFS_FS_TREE_OBJECTID;
503                                 else
504                                         *subvol_objectid = intarg;
505                         }
506                         break;
507                 case Opt_subvolrootid:
508                         intarg = 0;
509                         error = match_int(&args[0], &intarg);
510                         if (!error) {
511                                 /* we want the original fs_tree */
512                                 if (!intarg)
513                                         *subvol_rootid =
514                                                 BTRFS_FS_TREE_OBJECTID;
515                                 else
516                                         *subvol_rootid = intarg;
517                         }
518                         break;
519                 case Opt_device:
520                         device_name = match_strdup(&args[0]);
521                         if (!device_name) {
522                                 error = -ENOMEM;
523                                 goto out;
524                         }
525                         error = btrfs_scan_one_device(device_name,
526                                         flags, holder, fs_devices);
527                         kfree(device_name);
528                         if (error)
529                                 goto out;
530                         break;
531                 default:
532                         break;
533                 }
534         }
535
536 out:
537         kfree(orig);
538         return error;
539 }
540
541 static struct dentry *get_default_root(struct super_block *sb,
542                                        u64 subvol_objectid)
543 {
544         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
545         struct btrfs_root *root = fs_info->tree_root;
546         struct btrfs_root *new_root;
547         struct btrfs_dir_item *di;
548         struct btrfs_path *path;
549         struct btrfs_key location;
550         struct inode *inode;
551         u64 dir_id;
552         int new = 0;
553
554         /*
555          * We have a specific subvol we want to mount, just setup location and
556          * go look up the root.
557          */
558         if (subvol_objectid) {
559                 location.objectid = subvol_objectid;
560                 location.type = BTRFS_ROOT_ITEM_KEY;
561                 location.offset = (u64)-1;
562                 goto find_root;
563         }
564
565         path = btrfs_alloc_path();
566         if (!path)
567                 return ERR_PTR(-ENOMEM);
568         path->leave_spinning = 1;
569
570         /*
571          * Find the "default" dir item which points to the root item that we
572          * will mount by default if we haven't been given a specific subvolume
573          * to mount.
574          */
575         dir_id = btrfs_super_root_dir(fs_info->super_copy);
576         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
577         if (IS_ERR(di)) {
578                 btrfs_free_path(path);
579                 return ERR_CAST(di);
580         }
581         if (!di) {
582                 /*
583                  * Ok the default dir item isn't there.  This is weird since
584                  * it's always been there, but don't freak out, just try and
585                  * mount to root most subvolume.
586                  */
587                 btrfs_free_path(path);
588                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
589                 new_root = fs_info->fs_root;
590                 goto setup_root;
591         }
592
593         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
594         btrfs_free_path(path);
595
596 find_root:
597         new_root = btrfs_read_fs_root_no_name(fs_info, &location);
598         if (IS_ERR(new_root))
599                 return ERR_CAST(new_root);
600
601         if (btrfs_root_refs(&new_root->root_item) == 0)
602                 return ERR_PTR(-ENOENT);
603
604         dir_id = btrfs_root_dirid(&new_root->root_item);
605 setup_root:
606         location.objectid = dir_id;
607         location.type = BTRFS_INODE_ITEM_KEY;
608         location.offset = 0;
609
610         inode = btrfs_iget(sb, &location, new_root, &new);
611         if (IS_ERR(inode))
612                 return ERR_CAST(inode);
613
614         /*
615          * If we're just mounting the root most subvol put the inode and return
616          * a reference to the dentry.  We will have already gotten a reference
617          * to the inode in btrfs_fill_super so we're good to go.
618          */
619         if (!new && sb->s_root->d_inode == inode) {
620                 iput(inode);
621                 return dget(sb->s_root);
622         }
623
624         return d_obtain_alias(inode);
625 }
626
627 static int btrfs_fill_super(struct super_block *sb,
628                             struct btrfs_fs_devices *fs_devices,
629                             void *data, int silent)
630 {
631         struct inode *inode;
632         struct dentry *root_dentry;
633         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
634         struct btrfs_key key;
635         int err;
636
637         sb->s_maxbytes = MAX_LFS_FILESIZE;
638         sb->s_magic = BTRFS_SUPER_MAGIC;
639         sb->s_op = &btrfs_super_ops;
640         sb->s_d_op = &btrfs_dentry_operations;
641         sb->s_export_op = &btrfs_export_ops;
642         sb->s_xattr = btrfs_xattr_handlers;
643         sb->s_time_gran = 1;
644 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
645         sb->s_flags |= MS_POSIXACL;
646 #endif
647
648         err = open_ctree(sb, fs_devices, (char *)data);
649         if (err) {
650                 printk("btrfs: open_ctree failed\n");
651                 return err;
652         }
653
654         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
655         key.type = BTRFS_INODE_ITEM_KEY;
656         key.offset = 0;
657         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
658         if (IS_ERR(inode)) {
659                 err = PTR_ERR(inode);
660                 goto fail_close;
661         }
662
663         root_dentry = d_alloc_root(inode);
664         if (!root_dentry) {
665                 iput(inode);
666                 err = -ENOMEM;
667                 goto fail_close;
668         }
669
670         sb->s_root = root_dentry;
671
672         save_mount_options(sb, data);
673         cleancache_init_fs(sb);
674         sb->s_flags |= MS_ACTIVE;
675         return 0;
676
677 fail_close:
678         close_ctree(fs_info->tree_root);
679         return err;
680 }
681
682 int btrfs_sync_fs(struct super_block *sb, int wait)
683 {
684         struct btrfs_trans_handle *trans;
685         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
686         struct btrfs_root *root = fs_info->tree_root;
687         int ret;
688
689         trace_btrfs_sync_fs(wait);
690
691         if (!wait) {
692                 filemap_flush(fs_info->btree_inode->i_mapping);
693                 return 0;
694         }
695
696         btrfs_start_delalloc_inodes(root, 0);
697         btrfs_wait_ordered_extents(root, 0, 0);
698
699         trans = btrfs_start_transaction(root, 0);
700         if (IS_ERR(trans))
701                 return PTR_ERR(trans);
702         ret = btrfs_commit_transaction(trans, root);
703         return ret;
704 }
705
706 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
707 {
708         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
709         struct btrfs_root *root = info->tree_root;
710         char *compress_type;
711
712         if (btrfs_test_opt(root, DEGRADED))
713                 seq_puts(seq, ",degraded");
714         if (btrfs_test_opt(root, NODATASUM))
715                 seq_puts(seq, ",nodatasum");
716         if (btrfs_test_opt(root, NODATACOW))
717                 seq_puts(seq, ",nodatacow");
718         if (btrfs_test_opt(root, NOBARRIER))
719                 seq_puts(seq, ",nobarrier");
720         if (info->max_inline != 8192 * 1024)
721                 seq_printf(seq, ",max_inline=%llu",
722                            (unsigned long long)info->max_inline);
723         if (info->alloc_start != 0)
724                 seq_printf(seq, ",alloc_start=%llu",
725                            (unsigned long long)info->alloc_start);
726         if (info->thread_pool_size !=  min_t(unsigned long,
727                                              num_online_cpus() + 2, 8))
728                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
729         if (btrfs_test_opt(root, COMPRESS)) {
730                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
731                         compress_type = "zlib";
732                 else
733                         compress_type = "lzo";
734                 if (btrfs_test_opt(root, FORCE_COMPRESS))
735                         seq_printf(seq, ",compress-force=%s", compress_type);
736                 else
737                         seq_printf(seq, ",compress=%s", compress_type);
738         }
739         if (btrfs_test_opt(root, NOSSD))
740                 seq_puts(seq, ",nossd");
741         if (btrfs_test_opt(root, SSD_SPREAD))
742                 seq_puts(seq, ",ssd_spread");
743         else if (btrfs_test_opt(root, SSD))
744                 seq_puts(seq, ",ssd");
745         if (btrfs_test_opt(root, NOTREELOG))
746                 seq_puts(seq, ",notreelog");
747         if (btrfs_test_opt(root, FLUSHONCOMMIT))
748                 seq_puts(seq, ",flushoncommit");
749         if (btrfs_test_opt(root, DISCARD))
750                 seq_puts(seq, ",discard");
751         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
752                 seq_puts(seq, ",noacl");
753         if (btrfs_test_opt(root, SPACE_CACHE))
754                 seq_puts(seq, ",space_cache");
755         else
756                 seq_puts(seq, ",nospace_cache");
757         if (btrfs_test_opt(root, CLEAR_CACHE))
758                 seq_puts(seq, ",clear_cache");
759         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
760                 seq_puts(seq, ",user_subvol_rm_allowed");
761         if (btrfs_test_opt(root, ENOSPC_DEBUG))
762                 seq_puts(seq, ",enospc_debug");
763         if (btrfs_test_opt(root, AUTO_DEFRAG))
764                 seq_puts(seq, ",autodefrag");
765         if (btrfs_test_opt(root, INODE_MAP_CACHE))
766                 seq_puts(seq, ",inode_cache");
767         if (btrfs_test_opt(root, SKIP_BALANCE))
768                 seq_puts(seq, ",skip_balance");
769         return 0;
770 }
771
772 static int btrfs_test_super(struct super_block *s, void *data)
773 {
774         struct btrfs_fs_info *p = data;
775         struct btrfs_fs_info *fs_info = btrfs_sb(s);
776
777         return fs_info->fs_devices == p->fs_devices;
778 }
779
780 static int btrfs_set_super(struct super_block *s, void *data)
781 {
782         int err = set_anon_super(s, data);
783         if (!err)
784                 s->s_fs_info = data;
785         return err;
786 }
787
788 /*
789  * subvolumes are identified by ino 256
790  */
791 static inline int is_subvolume_inode(struct inode *inode)
792 {
793         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
794                 return 1;
795         return 0;
796 }
797
798 /*
799  * This will strip out the subvol=%s argument for an argument string and add
800  * subvolid=0 to make sure we get the actual tree root for path walking to the
801  * subvol we want.
802  */
803 static char *setup_root_args(char *args)
804 {
805         unsigned copied = 0;
806         unsigned len = strlen(args) + 2;
807         char *pos;
808         char *ret;
809
810         /*
811          * We need the same args as before, but minus
812          *
813          * subvol=a
814          *
815          * and add
816          *
817          * subvolid=0
818          *
819          * which is a difference of 2 characters, so we allocate strlen(args) +
820          * 2 characters.
821          */
822         ret = kzalloc(len * sizeof(char), GFP_NOFS);
823         if (!ret)
824                 return NULL;
825         pos = strstr(args, "subvol=");
826
827         /* This shouldn't happen, but just in case.. */
828         if (!pos) {
829                 kfree(ret);
830                 return NULL;
831         }
832
833         /*
834          * The subvol=<> arg is not at the front of the string, copy everybody
835          * up to that into ret.
836          */
837         if (pos != args) {
838                 *pos = '\0';
839                 strcpy(ret, args);
840                 copied += strlen(args);
841                 pos++;
842         }
843
844         strncpy(ret + copied, "subvolid=0", len - copied);
845
846         /* Length of subvolid=0 */
847         copied += 10;
848
849         /*
850          * If there is no , after the subvol= option then we know there's no
851          * other options and we can just return.
852          */
853         pos = strchr(pos, ',');
854         if (!pos)
855                 return ret;
856
857         /* Copy the rest of the arguments into our buffer */
858         strncpy(ret + copied, pos, len - copied);
859         copied += strlen(pos);
860
861         return ret;
862 }
863
864 static struct dentry *mount_subvol(const char *subvol_name, int flags,
865                                    const char *device_name, char *data)
866 {
867         struct dentry *root;
868         struct vfsmount *mnt;
869         char *newargs;
870
871         newargs = setup_root_args(data);
872         if (!newargs)
873                 return ERR_PTR(-ENOMEM);
874         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
875                              newargs);
876         kfree(newargs);
877         if (IS_ERR(mnt))
878                 return ERR_CAST(mnt);
879
880         root = mount_subtree(mnt, subvol_name);
881
882         if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
883                 struct super_block *s = root->d_sb;
884                 dput(root);
885                 root = ERR_PTR(-EINVAL);
886                 deactivate_locked_super(s);
887                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
888                                 subvol_name);
889         }
890
891         return root;
892 }
893
894 /*
895  * Find a superblock for the given device / mount point.
896  *
897  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
898  *        for multiple device setup.  Make sure to keep it in sync.
899  */
900 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
901                 const char *device_name, void *data)
902 {
903         struct block_device *bdev = NULL;
904         struct super_block *s;
905         struct dentry *root;
906         struct btrfs_fs_devices *fs_devices = NULL;
907         struct btrfs_fs_info *fs_info = NULL;
908         fmode_t mode = FMODE_READ;
909         char *subvol_name = NULL;
910         u64 subvol_objectid = 0;
911         u64 subvol_rootid = 0;
912         int error = 0;
913
914         if (!(flags & MS_RDONLY))
915                 mode |= FMODE_WRITE;
916
917         error = btrfs_parse_early_options(data, mode, fs_type,
918                                           &subvol_name, &subvol_objectid,
919                                           &subvol_rootid, &fs_devices);
920         if (error) {
921                 kfree(subvol_name);
922                 return ERR_PTR(error);
923         }
924
925         if (subvol_name) {
926                 root = mount_subvol(subvol_name, flags, device_name, data);
927                 kfree(subvol_name);
928                 return root;
929         }
930
931         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
932         if (error)
933                 return ERR_PTR(error);
934
935         /*
936          * Setup a dummy root and fs_info for test/set super.  This is because
937          * we don't actually fill this stuff out until open_ctree, but we need
938          * it for searching for existing supers, so this lets us do that and
939          * then open_ctree will properly initialize everything later.
940          */
941         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
942         if (!fs_info)
943                 return ERR_PTR(-ENOMEM);
944
945         fs_info->fs_devices = fs_devices;
946
947         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
948         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
949         if (!fs_info->super_copy || !fs_info->super_for_commit) {
950                 error = -ENOMEM;
951                 goto error_fs_info;
952         }
953
954         error = btrfs_open_devices(fs_devices, mode, fs_type);
955         if (error)
956                 goto error_fs_info;
957
958         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
959                 error = -EACCES;
960                 goto error_close_devices;
961         }
962
963         bdev = fs_devices->latest_bdev;
964         s = sget(fs_type, btrfs_test_super, btrfs_set_super, fs_info);
965         if (IS_ERR(s)) {
966                 error = PTR_ERR(s);
967                 goto error_close_devices;
968         }
969
970         if (s->s_root) {
971                 btrfs_close_devices(fs_devices);
972                 free_fs_info(fs_info);
973                 if ((flags ^ s->s_flags) & MS_RDONLY)
974                         error = -EBUSY;
975         } else {
976                 char b[BDEVNAME_SIZE];
977
978                 s->s_flags = flags | MS_NOSEC;
979                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
980                 btrfs_sb(s)->bdev_holder = fs_type;
981                 error = btrfs_fill_super(s, fs_devices, data,
982                                          flags & MS_SILENT ? 1 : 0);
983         }
984
985         root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
986         if (IS_ERR(root))
987                 deactivate_locked_super(s);
988
989         return root;
990
991 error_close_devices:
992         btrfs_close_devices(fs_devices);
993 error_fs_info:
994         free_fs_info(fs_info);
995         return ERR_PTR(error);
996 }
997
998 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
999 {
1000         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1001         struct btrfs_root *root = fs_info->tree_root;
1002         int ret;
1003
1004         ret = btrfs_parse_options(root, data);
1005         if (ret)
1006                 return -EINVAL;
1007
1008         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1009                 return 0;
1010
1011         if (*flags & MS_RDONLY) {
1012                 sb->s_flags |= MS_RDONLY;
1013
1014                 ret =  btrfs_commit_super(root);
1015                 WARN_ON(ret);
1016         } else {
1017                 if (fs_info->fs_devices->rw_devices == 0)
1018                         return -EACCES;
1019
1020                 if (btrfs_super_log_root(fs_info->super_copy) != 0)
1021                         return -EINVAL;
1022
1023                 ret = btrfs_cleanup_fs_roots(fs_info);
1024                 WARN_ON(ret);
1025
1026                 /* recover relocation */
1027                 ret = btrfs_recover_relocation(root);
1028                 WARN_ON(ret);
1029
1030                 sb->s_flags &= ~MS_RDONLY;
1031         }
1032
1033         return 0;
1034 }
1035
1036 /* Used to sort the devices by max_avail(descending sort) */
1037 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1038                                        const void *dev_info2)
1039 {
1040         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1041             ((struct btrfs_device_info *)dev_info2)->max_avail)
1042                 return -1;
1043         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1044                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1045                 return 1;
1046         else
1047         return 0;
1048 }
1049
1050 /*
1051  * sort the devices by max_avail, in which max free extent size of each device
1052  * is stored.(Descending Sort)
1053  */
1054 static inline void btrfs_descending_sort_devices(
1055                                         struct btrfs_device_info *devices,
1056                                         size_t nr_devices)
1057 {
1058         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1059              btrfs_cmp_device_free_bytes, NULL);
1060 }
1061
1062 /*
1063  * The helper to calc the free space on the devices that can be used to store
1064  * file data.
1065  */
1066 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1067 {
1068         struct btrfs_fs_info *fs_info = root->fs_info;
1069         struct btrfs_device_info *devices_info;
1070         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1071         struct btrfs_device *device;
1072         u64 skip_space;
1073         u64 type;
1074         u64 avail_space;
1075         u64 used_space;
1076         u64 min_stripe_size;
1077         int min_stripes = 1, num_stripes = 1;
1078         int i = 0, nr_devices;
1079         int ret;
1080
1081         nr_devices = fs_info->fs_devices->open_devices;
1082         BUG_ON(!nr_devices);
1083
1084         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1085                                GFP_NOFS);
1086         if (!devices_info)
1087                 return -ENOMEM;
1088
1089         /* calc min stripe number for data space alloction */
1090         type = btrfs_get_alloc_profile(root, 1);
1091         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1092                 min_stripes = 2;
1093                 num_stripes = nr_devices;
1094         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1095                 min_stripes = 2;
1096                 num_stripes = 2;
1097         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1098                 min_stripes = 4;
1099                 num_stripes = 4;
1100         }
1101
1102         if (type & BTRFS_BLOCK_GROUP_DUP)
1103                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1104         else
1105                 min_stripe_size = BTRFS_STRIPE_LEN;
1106
1107         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1108                 if (!device->in_fs_metadata || !device->bdev)
1109                         continue;
1110
1111                 avail_space = device->total_bytes - device->bytes_used;
1112
1113                 /* align with stripe_len */
1114                 do_div(avail_space, BTRFS_STRIPE_LEN);
1115                 avail_space *= BTRFS_STRIPE_LEN;
1116
1117                 /*
1118                  * In order to avoid overwritting the superblock on the drive,
1119                  * btrfs starts at an offset of at least 1MB when doing chunk
1120                  * allocation.
1121                  */
1122                 skip_space = 1024 * 1024;
1123
1124                 /* user can set the offset in fs_info->alloc_start. */
1125                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1126                     device->total_bytes)
1127                         skip_space = max(fs_info->alloc_start, skip_space);
1128
1129                 /*
1130                  * btrfs can not use the free space in [0, skip_space - 1],
1131                  * we must subtract it from the total. In order to implement
1132                  * it, we account the used space in this range first.
1133                  */
1134                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1135                                                      &used_space);
1136                 if (ret) {
1137                         kfree(devices_info);
1138                         return ret;
1139                 }
1140
1141                 /* calc the free space in [0, skip_space - 1] */
1142                 skip_space -= used_space;
1143
1144                 /*
1145                  * we can use the free space in [0, skip_space - 1], subtract
1146                  * it from the total.
1147                  */
1148                 if (avail_space && avail_space >= skip_space)
1149                         avail_space -= skip_space;
1150                 else
1151                         avail_space = 0;
1152
1153                 if (avail_space < min_stripe_size)
1154                         continue;
1155
1156                 devices_info[i].dev = device;
1157                 devices_info[i].max_avail = avail_space;
1158
1159                 i++;
1160         }
1161
1162         nr_devices = i;
1163
1164         btrfs_descending_sort_devices(devices_info, nr_devices);
1165
1166         i = nr_devices - 1;
1167         avail_space = 0;
1168         while (nr_devices >= min_stripes) {
1169                 if (num_stripes > nr_devices)
1170                         num_stripes = nr_devices;
1171
1172                 if (devices_info[i].max_avail >= min_stripe_size) {
1173                         int j;
1174                         u64 alloc_size;
1175
1176                         avail_space += devices_info[i].max_avail * num_stripes;
1177                         alloc_size = devices_info[i].max_avail;
1178                         for (j = i + 1 - num_stripes; j <= i; j++)
1179                                 devices_info[j].max_avail -= alloc_size;
1180                 }
1181                 i--;
1182                 nr_devices--;
1183         }
1184
1185         kfree(devices_info);
1186         *free_bytes = avail_space;
1187         return 0;
1188 }
1189
1190 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1191 {
1192         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1193         struct btrfs_super_block *disk_super = fs_info->super_copy;
1194         struct list_head *head = &fs_info->space_info;
1195         struct btrfs_space_info *found;
1196         u64 total_used = 0;
1197         u64 total_free_data = 0;
1198         int bits = dentry->d_sb->s_blocksize_bits;
1199         __be32 *fsid = (__be32 *)fs_info->fsid;
1200         int ret;
1201
1202         /* holding chunk_muext to avoid allocating new chunks */
1203         mutex_lock(&fs_info->chunk_mutex);
1204         rcu_read_lock();
1205         list_for_each_entry_rcu(found, head, list) {
1206                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1207                         total_free_data += found->disk_total - found->disk_used;
1208                         total_free_data -=
1209                                 btrfs_account_ro_block_groups_free_space(found);
1210                 }
1211
1212                 total_used += found->disk_used;
1213         }
1214         rcu_read_unlock();
1215
1216         buf->f_namelen = BTRFS_NAME_LEN;
1217         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1218         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1219         buf->f_bsize = dentry->d_sb->s_blocksize;
1220         buf->f_type = BTRFS_SUPER_MAGIC;
1221         buf->f_bavail = total_free_data;
1222         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1223         if (ret) {
1224                 mutex_unlock(&fs_info->chunk_mutex);
1225                 return ret;
1226         }
1227         buf->f_bavail += total_free_data;
1228         buf->f_bavail = buf->f_bavail >> bits;
1229         mutex_unlock(&fs_info->chunk_mutex);
1230
1231         /* We treat it as constant endianness (it doesn't matter _which_)
1232            because we want the fsid to come out the same whether mounted
1233            on a big-endian or little-endian host */
1234         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1235         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1236         /* Mask in the root object ID too, to disambiguate subvols */
1237         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1238         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1239
1240         return 0;
1241 }
1242
1243 static void btrfs_kill_super(struct super_block *sb)
1244 {
1245         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1246         kill_anon_super(sb);
1247         free_fs_info(fs_info);
1248 }
1249
1250 static struct file_system_type btrfs_fs_type = {
1251         .owner          = THIS_MODULE,
1252         .name           = "btrfs",
1253         .mount          = btrfs_mount,
1254         .kill_sb        = btrfs_kill_super,
1255         .fs_flags       = FS_REQUIRES_DEV,
1256 };
1257
1258 /*
1259  * used by btrfsctl to scan devices when no FS is mounted
1260  */
1261 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1262                                 unsigned long arg)
1263 {
1264         struct btrfs_ioctl_vol_args *vol;
1265         struct btrfs_fs_devices *fs_devices;
1266         int ret = -ENOTTY;
1267
1268         if (!capable(CAP_SYS_ADMIN))
1269                 return -EPERM;
1270
1271         vol = memdup_user((void __user *)arg, sizeof(*vol));
1272         if (IS_ERR(vol))
1273                 return PTR_ERR(vol);
1274
1275         switch (cmd) {
1276         case BTRFS_IOC_SCAN_DEV:
1277                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1278                                             &btrfs_fs_type, &fs_devices);
1279                 break;
1280         }
1281
1282         kfree(vol);
1283         return ret;
1284 }
1285
1286 static int btrfs_freeze(struct super_block *sb)
1287 {
1288         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1289         mutex_lock(&fs_info->transaction_kthread_mutex);
1290         mutex_lock(&fs_info->cleaner_mutex);
1291         return 0;
1292 }
1293
1294 static int btrfs_unfreeze(struct super_block *sb)
1295 {
1296         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1297         mutex_unlock(&fs_info->cleaner_mutex);
1298         mutex_unlock(&fs_info->transaction_kthread_mutex);
1299         return 0;
1300 }
1301
1302 static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
1303 {
1304         int ret;
1305
1306         ret = btrfs_dirty_inode(inode);
1307         if (ret)
1308                 printk_ratelimited(KERN_ERR "btrfs: fail to dirty inode %Lu "
1309                                    "error %d\n", btrfs_ino(inode), ret);
1310 }
1311
1312 static const struct super_operations btrfs_super_ops = {
1313         .drop_inode     = btrfs_drop_inode,
1314         .evict_inode    = btrfs_evict_inode,
1315         .put_super      = btrfs_put_super,
1316         .sync_fs        = btrfs_sync_fs,
1317         .show_options   = btrfs_show_options,
1318         .write_inode    = btrfs_write_inode,
1319         .dirty_inode    = btrfs_fs_dirty_inode,
1320         .alloc_inode    = btrfs_alloc_inode,
1321         .destroy_inode  = btrfs_destroy_inode,
1322         .statfs         = btrfs_statfs,
1323         .remount_fs     = btrfs_remount,
1324         .freeze_fs      = btrfs_freeze,
1325         .unfreeze_fs    = btrfs_unfreeze,
1326 };
1327
1328 static const struct file_operations btrfs_ctl_fops = {
1329         .unlocked_ioctl  = btrfs_control_ioctl,
1330         .compat_ioctl = btrfs_control_ioctl,
1331         .owner   = THIS_MODULE,
1332         .llseek = noop_llseek,
1333 };
1334
1335 static struct miscdevice btrfs_misc = {
1336         .minor          = BTRFS_MINOR,
1337         .name           = "btrfs-control",
1338         .fops           = &btrfs_ctl_fops
1339 };
1340
1341 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1342 MODULE_ALIAS("devname:btrfs-control");
1343
1344 static int btrfs_interface_init(void)
1345 {
1346         return misc_register(&btrfs_misc);
1347 }
1348
1349 static void btrfs_interface_exit(void)
1350 {
1351         if (misc_deregister(&btrfs_misc) < 0)
1352                 printk(KERN_INFO "misc_deregister failed for control device");
1353 }
1354
1355 static int __init init_btrfs_fs(void)
1356 {
1357         int err;
1358
1359         err = btrfs_init_sysfs();
1360         if (err)
1361                 return err;
1362
1363         err = btrfs_init_compress();
1364         if (err)
1365                 goto free_sysfs;
1366
1367         err = btrfs_init_cachep();
1368         if (err)
1369                 goto free_compress;
1370
1371         err = extent_io_init();
1372         if (err)
1373                 goto free_cachep;
1374
1375         err = extent_map_init();
1376         if (err)
1377                 goto free_extent_io;
1378
1379         err = btrfs_delayed_inode_init();
1380         if (err)
1381                 goto free_extent_map;
1382
1383         err = btrfs_interface_init();
1384         if (err)
1385                 goto free_delayed_inode;
1386
1387         err = register_filesystem(&btrfs_fs_type);
1388         if (err)
1389                 goto unregister_ioctl;
1390
1391         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1392         return 0;
1393
1394 unregister_ioctl:
1395         btrfs_interface_exit();
1396 free_delayed_inode:
1397         btrfs_delayed_inode_exit();
1398 free_extent_map:
1399         extent_map_exit();
1400 free_extent_io:
1401         extent_io_exit();
1402 free_cachep:
1403         btrfs_destroy_cachep();
1404 free_compress:
1405         btrfs_exit_compress();
1406 free_sysfs:
1407         btrfs_exit_sysfs();
1408         return err;
1409 }
1410
1411 static void __exit exit_btrfs_fs(void)
1412 {
1413         btrfs_destroy_cachep();
1414         btrfs_delayed_inode_exit();
1415         extent_map_exit();
1416         extent_io_exit();
1417         btrfs_interface_exit();
1418         unregister_filesystem(&btrfs_fs_type);
1419         btrfs_exit_sysfs();
1420         btrfs_cleanup_fs_uuids();
1421         btrfs_exit_compress();
1422 }
1423
1424 module_init(init_btrfs_fs)
1425 module_exit(exit_btrfs_fs)
1426
1427 MODULE_LICENSE("GPL");