Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/super.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * super.c contains code to handle: - mount structures | |
7 | * - super-block tables | |
8 | * - filesystem drivers list | |
9 | * - mount system call | |
10 | * - umount system call | |
11 | * - ustat system call | |
12 | * | |
13 | * GK 2/5/95 - Changed to support mounting the root fs via NFS | |
14 | * | |
15 | * Added kerneld support: Jacques Gelinas and Bjorn Ekwall | |
16 | * Added change_root: Werner Almesberger & Hans Lermen, Feb '96 | |
17 | * Added options to /proc/mounts: | |
96de0e25 | 18 | * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996. |
1da177e4 LT |
19 | * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998 |
20 | * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000 | |
21 | */ | |
22 | ||
1da177e4 LT |
23 | #include <linux/module.h> |
24 | #include <linux/slab.h> | |
1da177e4 LT |
25 | #include <linux/acct.h> |
26 | #include <linux/blkdev.h> | |
27 | #include <linux/quotaops.h> | |
1da177e4 LT |
28 | #include <linux/mount.h> |
29 | #include <linux/security.h> | |
1da177e4 LT |
30 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
31 | #include <linux/idr.h> | |
353ab6e9 | 32 | #include <linux/mutex.h> |
5477d0fa | 33 | #include <linux/backing-dev.h> |
6d59e7f5 | 34 | #include "internal.h" |
1da177e4 LT |
35 | |
36 | ||
1da177e4 LT |
37 | LIST_HEAD(super_blocks); |
38 | DEFINE_SPINLOCK(sb_lock); | |
39 | ||
40 | /** | |
41 | * alloc_super - create new superblock | |
fe2bbc48 | 42 | * @type: filesystem type superblock should belong to |
1da177e4 LT |
43 | * |
44 | * Allocates and initializes a new &struct super_block. alloc_super() | |
45 | * returns a pointer new superblock or %NULL if allocation had failed. | |
46 | */ | |
cf516249 | 47 | static struct super_block *alloc_super(struct file_system_type *type) |
1da177e4 | 48 | { |
11b0b5ab | 49 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
b87221de | 50 | static const struct super_operations default_op; |
1da177e4 LT |
51 | |
52 | if (s) { | |
1da177e4 LT |
53 | if (security_sb_alloc(s)) { |
54 | kfree(s); | |
55 | s = NULL; | |
56 | goto out; | |
57 | } | |
1da177e4 LT |
58 | INIT_LIST_HEAD(&s->s_files); |
59 | INIT_LIST_HEAD(&s->s_instances); | |
60 | INIT_HLIST_HEAD(&s->s_anon); | |
61 | INIT_LIST_HEAD(&s->s_inodes); | |
da3bbdd4 | 62 | INIT_LIST_HEAD(&s->s_dentry_lru); |
1da177e4 | 63 | init_rwsem(&s->s_umount); |
7892f2f4 | 64 | mutex_init(&s->s_lock); |
897c6ff9 | 65 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
cf516249 IM |
66 | /* |
67 | * The locking rules for s_lock are up to the | |
68 | * filesystem. For example ext3fs has different | |
69 | * lock ordering than usbfs: | |
70 | */ | |
71 | lockdep_set_class(&s->s_lock, &type->s_lock_key); | |
ada723dc PZ |
72 | /* |
73 | * sget() can have s_umount recursion. | |
74 | * | |
75 | * When it cannot find a suitable sb, it allocates a new | |
76 | * one (this one), and tries again to find a suitable old | |
77 | * one. | |
78 | * | |
79 | * In case that succeeds, it will acquire the s_umount | |
80 | * lock of the old one. Since these are clearly distrinct | |
81 | * locks, and this object isn't exposed yet, there's no | |
82 | * risk of deadlocks. | |
83 | * | |
84 | * Annotate this by putting this lock in a different | |
85 | * subclass. | |
86 | */ | |
87 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); | |
b20bd1a5 | 88 | s->s_count = 1; |
1da177e4 | 89 | atomic_set(&s->s_active, 1); |
a11f3a05 | 90 | mutex_init(&s->s_vfs_rename_mutex); |
d3be915f IM |
91 | mutex_init(&s->s_dquot.dqio_mutex); |
92 | mutex_init(&s->s_dquot.dqonoff_mutex); | |
1da177e4 LT |
93 | init_rwsem(&s->s_dquot.dqptr_sem); |
94 | init_waitqueue_head(&s->s_wait_unfrozen); | |
95 | s->s_maxbytes = MAX_NON_LFS; | |
96 | s->dq_op = sb_dquot_ops; | |
97 | s->s_qcop = sb_quotactl_ops; | |
98 | s->s_op = &default_op; | |
99 | s->s_time_gran = 1000000000; | |
100 | } | |
101 | out: | |
102 | return s; | |
103 | } | |
104 | ||
105 | /** | |
106 | * destroy_super - frees a superblock | |
107 | * @s: superblock to free | |
108 | * | |
109 | * Frees a superblock. | |
110 | */ | |
111 | static inline void destroy_super(struct super_block *s) | |
112 | { | |
113 | security_sb_free(s); | |
79c0b2df | 114 | kfree(s->s_subtype); |
b3b304a2 | 115 | kfree(s->s_options); |
1da177e4 LT |
116 | kfree(s); |
117 | } | |
118 | ||
119 | /* Superblock refcounting */ | |
120 | ||
121 | /* | |
35cf7ba0 | 122 | * Drop a superblock's refcount. The caller must hold sb_lock. |
1da177e4 | 123 | */ |
35cf7ba0 | 124 | void __put_super(struct super_block *sb) |
1da177e4 | 125 | { |
1da177e4 | 126 | if (!--sb->s_count) { |
551de6f3 | 127 | list_del_init(&sb->s_list); |
1da177e4 | 128 | destroy_super(sb); |
1da177e4 | 129 | } |
1da177e4 LT |
130 | } |
131 | ||
132 | /** | |
133 | * put_super - drop a temporary reference to superblock | |
134 | * @sb: superblock in question | |
135 | * | |
136 | * Drops a temporary reference, frees superblock if there's no | |
137 | * references left. | |
138 | */ | |
03ba3782 | 139 | void put_super(struct super_block *sb) |
1da177e4 LT |
140 | { |
141 | spin_lock(&sb_lock); | |
142 | __put_super(sb); | |
143 | spin_unlock(&sb_lock); | |
144 | } | |
145 | ||
146 | ||
147 | /** | |
1712ac8f | 148 | * deactivate_locked_super - drop an active reference to superblock |
1da177e4 LT |
149 | * @s: superblock to deactivate |
150 | * | |
1712ac8f AV |
151 | * Drops an active reference to superblock, converting it into a temprory |
152 | * one if there is no other active references left. In that case we | |
1da177e4 LT |
153 | * tell fs driver to shut it down and drop the temporary reference we |
154 | * had just acquired. | |
1712ac8f AV |
155 | * |
156 | * Caller holds exclusive lock on superblock; that lock is released. | |
1da177e4 | 157 | */ |
1712ac8f | 158 | void deactivate_locked_super(struct super_block *s) |
1da177e4 LT |
159 | { |
160 | struct file_system_type *fs = s->s_type; | |
b20bd1a5 | 161 | if (atomic_dec_and_test(&s->s_active)) { |
9e3509e2 | 162 | vfs_dq_off(s, 0); |
1da177e4 LT |
163 | fs->kill_sb(s); |
164 | put_filesystem(fs); | |
165 | put_super(s); | |
1712ac8f AV |
166 | } else { |
167 | up_write(&s->s_umount); | |
1da177e4 LT |
168 | } |
169 | } | |
170 | ||
1712ac8f | 171 | EXPORT_SYMBOL(deactivate_locked_super); |
1da177e4 | 172 | |
74dbbdd7 | 173 | /** |
1712ac8f | 174 | * deactivate_super - drop an active reference to superblock |
74dbbdd7 AV |
175 | * @s: superblock to deactivate |
176 | * | |
1712ac8f AV |
177 | * Variant of deactivate_locked_super(), except that superblock is *not* |
178 | * locked by caller. If we are going to drop the final active reference, | |
179 | * lock will be acquired prior to that. | |
74dbbdd7 | 180 | */ |
1712ac8f | 181 | void deactivate_super(struct super_block *s) |
74dbbdd7 | 182 | { |
1712ac8f AV |
183 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
184 | down_write(&s->s_umount); | |
185 | deactivate_locked_super(s); | |
74dbbdd7 AV |
186 | } |
187 | } | |
188 | ||
1712ac8f | 189 | EXPORT_SYMBOL(deactivate_super); |
74dbbdd7 | 190 | |
1da177e4 LT |
191 | /** |
192 | * grab_super - acquire an active reference | |
193 | * @s: reference we are trying to make active | |
194 | * | |
195 | * Tries to acquire an active reference. grab_super() is used when we | |
196 | * had just found a superblock in super_blocks or fs_type->fs_supers | |
197 | * and want to turn it into a full-blown active reference. grab_super() | |
198 | * is called with sb_lock held and drops it. Returns 1 in case of | |
199 | * success, 0 if we had failed (superblock contents was already dead or | |
200 | * dying when grab_super() had been called). | |
201 | */ | |
9c4dbee7 | 202 | static int grab_super(struct super_block *s) __releases(sb_lock) |
1da177e4 | 203 | { |
b20bd1a5 AV |
204 | if (atomic_inc_not_zero(&s->s_active)) { |
205 | spin_unlock(&sb_lock); | |
b20bd1a5 AV |
206 | return 1; |
207 | } | |
208 | /* it's going away */ | |
1da177e4 LT |
209 | s->s_count++; |
210 | spin_unlock(&sb_lock); | |
1712ac8f | 211 | /* wait for it to die */ |
1da177e4 | 212 | down_write(&s->s_umount); |
1da177e4 LT |
213 | up_write(&s->s_umount); |
214 | put_super(s); | |
1da177e4 LT |
215 | return 0; |
216 | } | |
217 | ||
914e2637 AV |
218 | /* |
219 | * Superblock locking. We really ought to get rid of these two. | |
220 | */ | |
221 | void lock_super(struct super_block * sb) | |
222 | { | |
223 | get_fs_excl(); | |
224 | mutex_lock(&sb->s_lock); | |
225 | } | |
226 | ||
227 | void unlock_super(struct super_block * sb) | |
228 | { | |
229 | put_fs_excl(); | |
230 | mutex_unlock(&sb->s_lock); | |
231 | } | |
232 | ||
233 | EXPORT_SYMBOL(lock_super); | |
234 | EXPORT_SYMBOL(unlock_super); | |
235 | ||
1da177e4 LT |
236 | /** |
237 | * generic_shutdown_super - common helper for ->kill_sb() | |
238 | * @sb: superblock to kill | |
239 | * | |
240 | * generic_shutdown_super() does all fs-independent work on superblock | |
241 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects | |
242 | * that need destruction out of superblock, call generic_shutdown_super() | |
243 | * and release aforementioned objects. Note: dentries and inodes _are_ | |
244 | * taken care of and do not need specific handling. | |
c636ebdb DH |
245 | * |
246 | * Upon calling this function, the filesystem may no longer alter or | |
247 | * rearrange the set of dentries belonging to this super_block, nor may it | |
248 | * change the attachments of dentries to inodes. | |
1da177e4 LT |
249 | */ |
250 | void generic_shutdown_super(struct super_block *sb) | |
251 | { | |
ee9b6d61 | 252 | const struct super_operations *sop = sb->s_op; |
1da177e4 | 253 | |
efaee192 | 254 | |
c636ebdb DH |
255 | if (sb->s_root) { |
256 | shrink_dcache_for_umount(sb); | |
60b0680f | 257 | sync_filesystem(sb); |
a9e220f8 | 258 | get_fs_excl(); |
1da177e4 | 259 | sb->s_flags &= ~MS_ACTIVE; |
efaee192 | 260 | |
1da177e4 LT |
261 | /* bad name - it should be evict_inodes() */ |
262 | invalidate_inodes(sb); | |
1da177e4 | 263 | |
1da177e4 LT |
264 | if (sop->put_super) |
265 | sop->put_super(sb); | |
266 | ||
267 | /* Forget any remaining inodes */ | |
268 | if (invalidate_inodes(sb)) { | |
7b4fe29e DJ |
269 | printk("VFS: Busy inodes after unmount of %s. " |
270 | "Self-destruct in 5 seconds. Have a nice day...\n", | |
271 | sb->s_id); | |
1da177e4 | 272 | } |
a9e220f8 | 273 | put_fs_excl(); |
1da177e4 LT |
274 | } |
275 | spin_lock(&sb_lock); | |
276 | /* should be initialized for __put_super_and_need_restart() */ | |
551de6f3 | 277 | list_del_init(&sb->s_instances); |
1da177e4 LT |
278 | spin_unlock(&sb_lock); |
279 | up_write(&sb->s_umount); | |
280 | } | |
281 | ||
282 | EXPORT_SYMBOL(generic_shutdown_super); | |
283 | ||
284 | /** | |
285 | * sget - find or create a superblock | |
286 | * @type: filesystem type superblock should belong to | |
287 | * @test: comparison callback | |
288 | * @set: setup callback | |
289 | * @data: argument to each of them | |
290 | */ | |
291 | struct super_block *sget(struct file_system_type *type, | |
292 | int (*test)(struct super_block *,void *), | |
293 | int (*set)(struct super_block *,void *), | |
294 | void *data) | |
295 | { | |
296 | struct super_block *s = NULL; | |
d4730127 | 297 | struct super_block *old; |
1da177e4 LT |
298 | int err; |
299 | ||
300 | retry: | |
301 | spin_lock(&sb_lock); | |
d4730127 MK |
302 | if (test) { |
303 | list_for_each_entry(old, &type->fs_supers, s_instances) { | |
304 | if (!test(old, data)) | |
305 | continue; | |
306 | if (!grab_super(old)) | |
307 | goto retry; | |
a3cfbb53 LZ |
308 | if (s) { |
309 | up_write(&s->s_umount); | |
d4730127 | 310 | destroy_super(s); |
a3cfbb53 | 311 | } |
d3f21473 | 312 | down_write(&old->s_umount); |
d4730127 MK |
313 | return old; |
314 | } | |
1da177e4 LT |
315 | } |
316 | if (!s) { | |
317 | spin_unlock(&sb_lock); | |
cf516249 | 318 | s = alloc_super(type); |
1da177e4 LT |
319 | if (!s) |
320 | return ERR_PTR(-ENOMEM); | |
321 | goto retry; | |
322 | } | |
323 | ||
324 | err = set(s, data); | |
325 | if (err) { | |
326 | spin_unlock(&sb_lock); | |
a3cfbb53 | 327 | up_write(&s->s_umount); |
1da177e4 LT |
328 | destroy_super(s); |
329 | return ERR_PTR(err); | |
330 | } | |
331 | s->s_type = type; | |
332 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
333 | list_add_tail(&s->s_list, &super_blocks); | |
334 | list_add(&s->s_instances, &type->fs_supers); | |
335 | spin_unlock(&sb_lock); | |
336 | get_filesystem(type); | |
337 | return s; | |
338 | } | |
339 | ||
340 | EXPORT_SYMBOL(sget); | |
341 | ||
342 | void drop_super(struct super_block *sb) | |
343 | { | |
344 | up_read(&sb->s_umount); | |
345 | put_super(sb); | |
346 | } | |
347 | ||
348 | EXPORT_SYMBOL(drop_super); | |
349 | ||
e5004753 CH |
350 | /** |
351 | * sync_supers - helper for periodic superblock writeback | |
352 | * | |
353 | * Call the write_super method if present on all dirty superblocks in | |
354 | * the system. This is for the periodic writeback used by most older | |
355 | * filesystems. For data integrity superblock writeback use | |
356 | * sync_filesystems() instead. | |
357 | * | |
1da177e4 LT |
358 | * Note: check the dirty flag before waiting, so we don't |
359 | * hold up the sync while mounting a device. (The newly | |
360 | * mounted device won't need syncing.) | |
361 | */ | |
362 | void sync_supers(void) | |
363 | { | |
6754af64 | 364 | struct super_block *sb, *n; |
618f0636 | 365 | |
1da177e4 | 366 | spin_lock(&sb_lock); |
6754af64 | 367 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { |
551de6f3 AV |
368 | if (list_empty(&sb->s_instances)) |
369 | continue; | |
e5004753 | 370 | if (sb->s_op->write_super && sb->s_dirt) { |
1da177e4 LT |
371 | sb->s_count++; |
372 | spin_unlock(&sb_lock); | |
e5004753 | 373 | |
1da177e4 | 374 | down_read(&sb->s_umount); |
e5004753 CH |
375 | if (sb->s_root && sb->s_dirt) |
376 | sb->s_op->write_super(sb); | |
618f0636 | 377 | up_read(&sb->s_umount); |
e5004753 | 378 | |
618f0636 | 379 | spin_lock(&sb_lock); |
6754af64 | 380 | __put_super(sb); |
618f0636 KK |
381 | } |
382 | } | |
1da177e4 LT |
383 | spin_unlock(&sb_lock); |
384 | } | |
385 | ||
01a05b33 AV |
386 | /** |
387 | * iterate_supers - call function for all active superblocks | |
388 | * @f: function to call | |
389 | * @arg: argument to pass to it | |
390 | * | |
391 | * Scans the superblock list and calls given function, passing it | |
392 | * locked superblock and given argument. | |
393 | */ | |
394 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) | |
395 | { | |
396 | struct super_block *sb, *n; | |
397 | ||
398 | spin_lock(&sb_lock); | |
399 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { | |
400 | if (list_empty(&sb->s_instances)) | |
401 | continue; | |
402 | sb->s_count++; | |
403 | spin_unlock(&sb_lock); | |
404 | ||
405 | down_read(&sb->s_umount); | |
406 | if (sb->s_root) | |
407 | f(sb, arg); | |
408 | up_read(&sb->s_umount); | |
409 | ||
410 | spin_lock(&sb_lock); | |
411 | __put_super(sb); | |
412 | } | |
413 | spin_unlock(&sb_lock); | |
414 | } | |
415 | ||
1da177e4 LT |
416 | /** |
417 | * get_super - get the superblock of a device | |
418 | * @bdev: device to get the superblock for | |
419 | * | |
420 | * Scans the superblock list and finds the superblock of the file system | |
421 | * mounted on the device given. %NULL is returned if no match is found. | |
422 | */ | |
423 | ||
df40c01a | 424 | struct super_block *get_super(struct block_device *bdev) |
1da177e4 | 425 | { |
618f0636 KK |
426 | struct super_block *sb; |
427 | ||
1da177e4 LT |
428 | if (!bdev) |
429 | return NULL; | |
618f0636 | 430 | |
1da177e4 | 431 | spin_lock(&sb_lock); |
618f0636 KK |
432 | rescan: |
433 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
434 | if (list_empty(&sb->s_instances)) |
435 | continue; | |
618f0636 KK |
436 | if (sb->s_bdev == bdev) { |
437 | sb->s_count++; | |
1da177e4 | 438 | spin_unlock(&sb_lock); |
618f0636 | 439 | down_read(&sb->s_umount); |
df40c01a | 440 | /* still alive? */ |
618f0636 KK |
441 | if (sb->s_root) |
442 | return sb; | |
443 | up_read(&sb->s_umount); | |
df40c01a | 444 | /* nope, got unmounted */ |
618f0636 | 445 | spin_lock(&sb_lock); |
df40c01a AV |
446 | __put_super(sb); |
447 | goto rescan; | |
1da177e4 LT |
448 | } |
449 | } | |
450 | spin_unlock(&sb_lock); | |
451 | return NULL; | |
452 | } | |
453 | ||
454 | EXPORT_SYMBOL(get_super); | |
4504230a CH |
455 | |
456 | /** | |
457 | * get_active_super - get an active reference to the superblock of a device | |
458 | * @bdev: device to get the superblock for | |
459 | * | |
460 | * Scans the superblock list and finds the superblock of the file system | |
461 | * mounted on the device given. Returns the superblock with an active | |
d3f21473 | 462 | * reference or %NULL if none was found. |
4504230a CH |
463 | */ |
464 | struct super_block *get_active_super(struct block_device *bdev) | |
465 | { | |
466 | struct super_block *sb; | |
467 | ||
468 | if (!bdev) | |
469 | return NULL; | |
470 | ||
1494583d | 471 | restart: |
4504230a CH |
472 | spin_lock(&sb_lock); |
473 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
474 | if (list_empty(&sb->s_instances)) |
475 | continue; | |
1494583d AV |
476 | if (sb->s_bdev == bdev) { |
477 | if (grab_super(sb)) /* drops sb_lock */ | |
478 | return sb; | |
479 | else | |
480 | goto restart; | |
481 | } | |
4504230a CH |
482 | } |
483 | spin_unlock(&sb_lock); | |
484 | return NULL; | |
485 | } | |
1da177e4 | 486 | |
df40c01a | 487 | struct super_block *user_get_super(dev_t dev) |
1da177e4 | 488 | { |
618f0636 | 489 | struct super_block *sb; |
1da177e4 | 490 | |
1da177e4 | 491 | spin_lock(&sb_lock); |
618f0636 KK |
492 | rescan: |
493 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
494 | if (list_empty(&sb->s_instances)) |
495 | continue; | |
618f0636 KK |
496 | if (sb->s_dev == dev) { |
497 | sb->s_count++; | |
1da177e4 | 498 | spin_unlock(&sb_lock); |
618f0636 | 499 | down_read(&sb->s_umount); |
df40c01a | 500 | /* still alive? */ |
618f0636 KK |
501 | if (sb->s_root) |
502 | return sb; | |
503 | up_read(&sb->s_umount); | |
df40c01a | 504 | /* nope, got unmounted */ |
618f0636 | 505 | spin_lock(&sb_lock); |
df40c01a AV |
506 | __put_super(sb); |
507 | goto rescan; | |
1da177e4 LT |
508 | } |
509 | } | |
510 | spin_unlock(&sb_lock); | |
511 | return NULL; | |
512 | } | |
513 | ||
1da177e4 LT |
514 | /** |
515 | * do_remount_sb - asks filesystem to change mount options. | |
516 | * @sb: superblock in question | |
517 | * @flags: numeric part of options | |
518 | * @data: the rest of options | |
519 | * @force: whether or not to force the change | |
520 | * | |
521 | * Alters the mount options of a mounted file system. | |
522 | */ | |
523 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
524 | { | |
525 | int retval; | |
d208bbdd | 526 | int remount_rw, remount_ro; |
4504230a CH |
527 | |
528 | if (sb->s_frozen != SB_UNFROZEN) | |
529 | return -EBUSY; | |
530 | ||
9361401e | 531 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
532 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
533 | return -EACCES; | |
9361401e | 534 | #endif |
4504230a | 535 | |
1da177e4 LT |
536 | if (flags & MS_RDONLY) |
537 | acct_auto_close(sb); | |
538 | shrink_dcache_sb(sb); | |
60b0680f | 539 | sync_filesystem(sb); |
1da177e4 | 540 | |
d208bbdd NP |
541 | remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); |
542 | remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); | |
543 | ||
1da177e4 LT |
544 | /* If we are remounting RDONLY and current sb is read/write, |
545 | make sure there are no rw files opened */ | |
d208bbdd | 546 | if (remount_ro) { |
1da177e4 LT |
547 | if (force) |
548 | mark_files_ro(sb); | |
b0895513 | 549 | else if (!fs_may_remount_ro(sb)) |
1da177e4 | 550 | return -EBUSY; |
9e3509e2 | 551 | retval = vfs_dq_off(sb, 1); |
b0895513 | 552 | if (retval < 0 && retval != -ENOSYS) |
0ff5af83 | 553 | return -EBUSY; |
1da177e4 LT |
554 | } |
555 | ||
556 | if (sb->s_op->remount_fs) { | |
1da177e4 | 557 | retval = sb->s_op->remount_fs(sb, &flags, data); |
b0895513 | 558 | if (retval) |
1da177e4 LT |
559 | return retval; |
560 | } | |
561 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
0ff5af83 | 562 | if (remount_rw) |
9e3509e2 | 563 | vfs_dq_quota_on_remount(sb); |
d208bbdd NP |
564 | /* |
565 | * Some filesystems modify their metadata via some other path than the | |
566 | * bdev buffer cache (eg. use a private mapping, or directories in | |
567 | * pagecache, etc). Also file data modifications go via their own | |
568 | * mappings. So If we try to mount readonly then copy the filesystem | |
569 | * from bdev, we could get stale data, so invalidate it to give a best | |
570 | * effort at coherency. | |
571 | */ | |
572 | if (remount_ro && sb->s_bdev) | |
573 | invalidate_bdev(sb->s_bdev); | |
1da177e4 LT |
574 | return 0; |
575 | } | |
576 | ||
a2a9537a | 577 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 | 578 | { |
e7fe0585 | 579 | struct super_block *sb, *n; |
1da177e4 LT |
580 | |
581 | spin_lock(&sb_lock); | |
e7fe0585 | 582 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { |
551de6f3 AV |
583 | if (list_empty(&sb->s_instances)) |
584 | continue; | |
1da177e4 LT |
585 | sb->s_count++; |
586 | spin_unlock(&sb_lock); | |
443b94ba | 587 | down_write(&sb->s_umount); |
1da177e4 LT |
588 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
589 | /* | |
1da177e4 LT |
590 | * What lock protects sb->s_flags?? |
591 | */ | |
1da177e4 | 592 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
1da177e4 | 593 | } |
443b94ba | 594 | up_write(&sb->s_umount); |
1da177e4 | 595 | spin_lock(&sb_lock); |
e7fe0585 | 596 | __put_super(sb); |
1da177e4 LT |
597 | } |
598 | spin_unlock(&sb_lock); | |
a2a9537a | 599 | kfree(work); |
1da177e4 LT |
600 | printk("Emergency Remount complete\n"); |
601 | } | |
602 | ||
603 | void emergency_remount(void) | |
604 | { | |
a2a9537a JA |
605 | struct work_struct *work; |
606 | ||
607 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
608 | if (work) { | |
609 | INIT_WORK(work, do_emergency_remount); | |
610 | schedule_work(work); | |
611 | } | |
1da177e4 LT |
612 | } |
613 | ||
614 | /* | |
615 | * Unnamed block devices are dummy devices used by virtual | |
616 | * filesystems which don't use real block-devices. -- jrs | |
617 | */ | |
618 | ||
ad76cbc6 | 619 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 | 620 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
c63e09ec | 621 | static int unnamed_dev_start = 0; /* don't bother trying below it */ |
1da177e4 LT |
622 | |
623 | int set_anon_super(struct super_block *s, void *data) | |
624 | { | |
625 | int dev; | |
626 | int error; | |
627 | ||
628 | retry: | |
ad76cbc6 | 629 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
630 | return -ENOMEM; |
631 | spin_lock(&unnamed_dev_lock); | |
c63e09ec | 632 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
f21f6220 AV |
633 | if (!error) |
634 | unnamed_dev_start = dev + 1; | |
1da177e4 LT |
635 | spin_unlock(&unnamed_dev_lock); |
636 | if (error == -EAGAIN) | |
637 | /* We raced and lost with another CPU. */ | |
638 | goto retry; | |
639 | else if (error) | |
640 | return -EAGAIN; | |
641 | ||
642 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
643 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 644 | ida_remove(&unnamed_dev_ida, dev); |
f21f6220 AV |
645 | if (unnamed_dev_start > dev) |
646 | unnamed_dev_start = dev; | |
1da177e4 LT |
647 | spin_unlock(&unnamed_dev_lock); |
648 | return -EMFILE; | |
649 | } | |
650 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
5129a469 | 651 | s->s_bdi = &noop_backing_dev_info; |
1da177e4 LT |
652 | return 0; |
653 | } | |
654 | ||
655 | EXPORT_SYMBOL(set_anon_super); | |
656 | ||
657 | void kill_anon_super(struct super_block *sb) | |
658 | { | |
659 | int slot = MINOR(sb->s_dev); | |
660 | ||
661 | generic_shutdown_super(sb); | |
662 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 663 | ida_remove(&unnamed_dev_ida, slot); |
c63e09ec AV |
664 | if (slot < unnamed_dev_start) |
665 | unnamed_dev_start = slot; | |
1da177e4 LT |
666 | spin_unlock(&unnamed_dev_lock); |
667 | } | |
668 | ||
669 | EXPORT_SYMBOL(kill_anon_super); | |
670 | ||
1da177e4 LT |
671 | void kill_litter_super(struct super_block *sb) |
672 | { | |
673 | if (sb->s_root) | |
674 | d_genocide(sb->s_root); | |
675 | kill_anon_super(sb); | |
676 | } | |
677 | ||
678 | EXPORT_SYMBOL(kill_litter_super); | |
679 | ||
909e6d94 SH |
680 | static int ns_test_super(struct super_block *sb, void *data) |
681 | { | |
682 | return sb->s_fs_info == data; | |
683 | } | |
684 | ||
685 | static int ns_set_super(struct super_block *sb, void *data) | |
686 | { | |
687 | sb->s_fs_info = data; | |
688 | return set_anon_super(sb, NULL); | |
689 | } | |
690 | ||
691 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
692 | int (*fill_super)(struct super_block *, void *, int), | |
693 | struct vfsmount *mnt) | |
694 | { | |
695 | struct super_block *sb; | |
696 | ||
697 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
698 | if (IS_ERR(sb)) | |
699 | return PTR_ERR(sb); | |
700 | ||
701 | if (!sb->s_root) { | |
702 | int err; | |
703 | sb->s_flags = flags; | |
704 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
705 | if (err) { | |
74dbbdd7 | 706 | deactivate_locked_super(sb); |
909e6d94 SH |
707 | return err; |
708 | } | |
709 | ||
710 | sb->s_flags |= MS_ACTIVE; | |
711 | } | |
712 | ||
713 | simple_set_mnt(mnt, sb); | |
714 | return 0; | |
715 | } | |
716 | ||
717 | EXPORT_SYMBOL(get_sb_ns); | |
718 | ||
9361401e | 719 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
720 | static int set_bdev_super(struct super_block *s, void *data) |
721 | { | |
722 | s->s_bdev = data; | |
723 | s->s_dev = s->s_bdev->bd_dev; | |
32a88aa1 JA |
724 | |
725 | /* | |
726 | * We set the bdi here to the queue backing, file systems can | |
727 | * overwrite this in ->fill_super() | |
728 | */ | |
729 | s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info; | |
1da177e4 LT |
730 | return 0; |
731 | } | |
732 | ||
733 | static int test_bdev_super(struct super_block *s, void *data) | |
734 | { | |
735 | return (void *)s->s_bdev == data; | |
736 | } | |
737 | ||
454e2398 | 738 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 739 | int flags, const char *dev_name, void *data, |
454e2398 DH |
740 | int (*fill_super)(struct super_block *, void *, int), |
741 | struct vfsmount *mnt) | |
1da177e4 LT |
742 | { |
743 | struct block_device *bdev; | |
744 | struct super_block *s; | |
30c40d2c | 745 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
746 | int error = 0; |
747 | ||
30c40d2c AV |
748 | if (!(flags & MS_RDONLY)) |
749 | mode |= FMODE_WRITE; | |
750 | ||
751 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 752 | if (IS_ERR(bdev)) |
454e2398 | 753 | return PTR_ERR(bdev); |
1da177e4 LT |
754 | |
755 | /* | |
756 | * once the super is inserted into the list by sget, s_umount | |
757 | * will protect the lockfs code from trying to start a snapshot | |
758 | * while we are mounting | |
759 | */ | |
4fadd7bb CH |
760 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
761 | if (bdev->bd_fsfreeze_count > 0) { | |
762 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
763 | error = -EBUSY; | |
764 | goto error_bdev; | |
765 | } | |
1da177e4 | 766 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
4fadd7bb | 767 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
1da177e4 | 768 | if (IS_ERR(s)) |
454e2398 | 769 | goto error_s; |
1da177e4 LT |
770 | |
771 | if (s->s_root) { | |
772 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 773 | deactivate_locked_super(s); |
454e2398 DH |
774 | error = -EBUSY; |
775 | goto error_bdev; | |
1da177e4 | 776 | } |
454e2398 | 777 | |
30c40d2c | 778 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
779 | } else { |
780 | char b[BDEVNAME_SIZE]; | |
781 | ||
782 | s->s_flags = flags; | |
30c40d2c | 783 | s->s_mode = mode; |
1da177e4 | 784 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 785 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 786 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 787 | if (error) { |
74dbbdd7 | 788 | deactivate_locked_super(s); |
454e2398 | 789 | goto error; |
fa675765 | 790 | } |
454e2398 DH |
791 | |
792 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 793 | bdev->bd_super = s; |
1da177e4 LT |
794 | } |
795 | ||
a3ec947c SB |
796 | simple_set_mnt(mnt, s); |
797 | return 0; | |
1da177e4 | 798 | |
454e2398 DH |
799 | error_s: |
800 | error = PTR_ERR(s); | |
801 | error_bdev: | |
30c40d2c | 802 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
803 | error: |
804 | return error; | |
1da177e4 LT |
805 | } |
806 | ||
807 | EXPORT_SYMBOL(get_sb_bdev); | |
808 | ||
809 | void kill_block_super(struct super_block *sb) | |
810 | { | |
811 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 812 | fmode_t mode = sb->s_mode; |
1da177e4 | 813 | |
ddbaaf30 | 814 | bdev->bd_super = NULL; |
1da177e4 LT |
815 | generic_shutdown_super(sb); |
816 | sync_blockdev(bdev); | |
30c40d2c | 817 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
818 | } |
819 | ||
820 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 821 | #endif |
1da177e4 | 822 | |
454e2398 | 823 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 824 | int flags, void *data, |
454e2398 DH |
825 | int (*fill_super)(struct super_block *, void *, int), |
826 | struct vfsmount *mnt) | |
1da177e4 LT |
827 | { |
828 | int error; | |
829 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
830 | ||
831 | if (IS_ERR(s)) | |
454e2398 | 832 | return PTR_ERR(s); |
1da177e4 LT |
833 | |
834 | s->s_flags = flags; | |
835 | ||
9b04c997 | 836 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 837 | if (error) { |
74dbbdd7 | 838 | deactivate_locked_super(s); |
454e2398 | 839 | return error; |
1da177e4 LT |
840 | } |
841 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
842 | simple_set_mnt(mnt, s); |
843 | return 0; | |
1da177e4 LT |
844 | } |
845 | ||
846 | EXPORT_SYMBOL(get_sb_nodev); | |
847 | ||
848 | static int compare_single(struct super_block *s, void *p) | |
849 | { | |
850 | return 1; | |
851 | } | |
852 | ||
454e2398 | 853 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 854 | int flags, void *data, |
454e2398 DH |
855 | int (*fill_super)(struct super_block *, void *, int), |
856 | struct vfsmount *mnt) | |
1da177e4 LT |
857 | { |
858 | struct super_block *s; | |
859 | int error; | |
860 | ||
861 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
862 | if (IS_ERR(s)) | |
454e2398 | 863 | return PTR_ERR(s); |
1da177e4 LT |
864 | if (!s->s_root) { |
865 | s->s_flags = flags; | |
9b04c997 | 866 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 867 | if (error) { |
74dbbdd7 | 868 | deactivate_locked_super(s); |
454e2398 | 869 | return error; |
1da177e4 LT |
870 | } |
871 | s->s_flags |= MS_ACTIVE; | |
9329d1be KS |
872 | } else { |
873 | do_remount_sb(s, flags, data, 0); | |
1da177e4 | 874 | } |
a3ec947c SB |
875 | simple_set_mnt(mnt, s); |
876 | return 0; | |
1da177e4 LT |
877 | } |
878 | ||
879 | EXPORT_SYMBOL(get_sb_single); | |
880 | ||
881 | struct vfsmount * | |
bb4a58bf | 882 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 883 | { |
1da177e4 | 884 | struct vfsmount *mnt; |
1da177e4 | 885 | char *secdata = NULL; |
454e2398 | 886 | int error; |
1da177e4 LT |
887 | |
888 | if (!type) | |
889 | return ERR_PTR(-ENODEV); | |
1da177e4 | 890 | |
454e2398 | 891 | error = -ENOMEM; |
1da177e4 LT |
892 | mnt = alloc_vfsmnt(name); |
893 | if (!mnt) | |
894 | goto out; | |
895 | ||
8089352a AV |
896 | if (flags & MS_KERNMOUNT) |
897 | mnt->mnt_flags = MNT_INTERNAL; | |
898 | ||
e0007529 | 899 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 900 | secdata = alloc_secdata(); |
454e2398 | 901 | if (!secdata) |
1da177e4 | 902 | goto out_mnt; |
1da177e4 | 903 | |
e0007529 | 904 | error = security_sb_copy_data(data, secdata); |
454e2398 | 905 | if (error) |
1da177e4 | 906 | goto out_free_secdata; |
1da177e4 LT |
907 | } |
908 | ||
454e2398 DH |
909 | error = type->get_sb(type, flags, name, data, mnt); |
910 | if (error < 0) | |
1da177e4 | 911 | goto out_free_secdata; |
b4c07bce | 912 | BUG_ON(!mnt->mnt_sb); |
5129a469 | 913 | WARN_ON(!mnt->mnt_sb->s_bdi); |
454e2398 | 914 | |
5129a469 JE |
915 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
916 | if (error) | |
917 | goto out_sb; | |
454e2398 | 918 | |
42cb56ae JL |
919 | /* |
920 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE | |
921 | * but s_maxbytes was an unsigned long long for many releases. Throw | |
922 | * this warning for a little while to try and catch filesystems that | |
923 | * violate this rule. This warning should be either removed or | |
924 | * converted to a BUG() in 2.6.34. | |
925 | */ | |
926 | WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " | |
927 | "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes); | |
928 | ||
454e2398 | 929 | mnt->mnt_mountpoint = mnt->mnt_root; |
1da177e4 | 930 | mnt->mnt_parent = mnt; |
454e2398 | 931 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 932 | free_secdata(secdata); |
1da177e4 LT |
933 | return mnt; |
934 | out_sb: | |
454e2398 | 935 | dput(mnt->mnt_root); |
74dbbdd7 | 936 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
937 | out_free_secdata: |
938 | free_secdata(secdata); | |
939 | out_mnt: | |
940 | free_vfsmnt(mnt); | |
941 | out: | |
454e2398 | 942 | return ERR_PTR(error); |
1da177e4 LT |
943 | } |
944 | ||
bb4a58bf TM |
945 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
946 | ||
18e9e510 JB |
947 | /** |
948 | * freeze_super -- lock the filesystem and force it into a consistent state | |
949 | * @super: the super to lock | |
950 | * | |
951 | * Syncs the super to make sure the filesystem is consistent and calls the fs's | |
952 | * freeze_fs. Subsequent calls to this without first thawing the fs will return | |
953 | * -EBUSY. | |
954 | */ | |
955 | int freeze_super(struct super_block *sb) | |
956 | { | |
957 | int ret; | |
958 | ||
959 | atomic_inc(&sb->s_active); | |
960 | down_write(&sb->s_umount); | |
961 | if (sb->s_frozen) { | |
962 | deactivate_locked_super(sb); | |
963 | return -EBUSY; | |
964 | } | |
965 | ||
966 | if (sb->s_flags & MS_RDONLY) { | |
967 | sb->s_frozen = SB_FREEZE_TRANS; | |
968 | smp_wmb(); | |
969 | up_write(&sb->s_umount); | |
970 | return 0; | |
971 | } | |
972 | ||
973 | sb->s_frozen = SB_FREEZE_WRITE; | |
974 | smp_wmb(); | |
975 | ||
976 | sync_filesystem(sb); | |
977 | ||
978 | sb->s_frozen = SB_FREEZE_TRANS; | |
979 | smp_wmb(); | |
980 | ||
981 | sync_blockdev(sb->s_bdev); | |
982 | if (sb->s_op->freeze_fs) { | |
983 | ret = sb->s_op->freeze_fs(sb); | |
984 | if (ret) { | |
985 | printk(KERN_ERR | |
986 | "VFS:Filesystem freeze failed\n"); | |
987 | sb->s_frozen = SB_UNFROZEN; | |
988 | deactivate_locked_super(sb); | |
989 | return ret; | |
990 | } | |
991 | } | |
992 | up_write(&sb->s_umount); | |
993 | return 0; | |
994 | } | |
995 | EXPORT_SYMBOL(freeze_super); | |
996 | ||
997 | /** | |
998 | * thaw_super -- unlock filesystem | |
999 | * @sb: the super to thaw | |
1000 | * | |
1001 | * Unlocks the filesystem and marks it writeable again after freeze_super(). | |
1002 | */ | |
1003 | int thaw_super(struct super_block *sb) | |
1004 | { | |
1005 | int error; | |
1006 | ||
1007 | down_write(&sb->s_umount); | |
1008 | if (sb->s_frozen == SB_UNFROZEN) { | |
1009 | up_write(&sb->s_umount); | |
1010 | return -EINVAL; | |
1011 | } | |
1012 | ||
1013 | if (sb->s_flags & MS_RDONLY) | |
1014 | goto out; | |
1015 | ||
1016 | if (sb->s_op->unfreeze_fs) { | |
1017 | error = sb->s_op->unfreeze_fs(sb); | |
1018 | if (error) { | |
1019 | printk(KERN_ERR | |
1020 | "VFS:Filesystem thaw failed\n"); | |
1021 | sb->s_frozen = SB_FREEZE_TRANS; | |
1022 | up_write(&sb->s_umount); | |
1023 | return error; | |
1024 | } | |
1025 | } | |
1026 | ||
1027 | out: | |
1028 | sb->s_frozen = SB_UNFROZEN; | |
1029 | smp_wmb(); | |
1030 | wake_up(&sb->s_wait_unfrozen); | |
1031 | deactivate_locked_super(sb); | |
1032 | ||
1033 | return 0; | |
1034 | } | |
1035 | EXPORT_SYMBOL(thaw_super); | |
1036 | ||
79c0b2df MS |
1037 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
1038 | { | |
1039 | int err; | |
1040 | const char *subtype = strchr(fstype, '.'); | |
1041 | if (subtype) { | |
1042 | subtype++; | |
1043 | err = -EINVAL; | |
1044 | if (!subtype[0]) | |
1045 | goto err; | |
1046 | } else | |
1047 | subtype = ""; | |
1048 | ||
1049 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
1050 | err = -ENOMEM; | |
1051 | if (!mnt->mnt_sb->s_subtype) | |
1052 | goto err; | |
1053 | return mnt; | |
1054 | ||
1055 | err: | |
1056 | mntput(mnt); | |
1057 | return ERR_PTR(err); | |
1058 | } | |
1059 | ||
bb4a58bf TM |
1060 | struct vfsmount * |
1061 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
1062 | { | |
1063 | struct file_system_type *type = get_fs_type(fstype); | |
1064 | struct vfsmount *mnt; | |
1065 | if (!type) | |
1066 | return ERR_PTR(-ENODEV); | |
1067 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
1068 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
1069 | !mnt->mnt_sb->s_subtype) | |
1070 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
1071 | put_filesystem(type); |
1072 | return mnt; | |
1073 | } | |
8a4e98d9 | 1074 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 1075 | |
8bf9725c | 1076 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 1077 | { |
8bf9725c | 1078 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
1079 | } |
1080 | ||
8bf9725c | 1081 | EXPORT_SYMBOL_GPL(kern_mount_data); |