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> | |
1da177e4 LT |
27 | #include <linux/mount.h> |
28 | #include <linux/security.h> | |
1da177e4 LT |
29 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
30 | #include <linux/idr.h> | |
353ab6e9 | 31 | #include <linux/mutex.h> |
5477d0fa | 32 | #include <linux/backing-dev.h> |
6d59e7f5 | 33 | #include "internal.h" |
1da177e4 LT |
34 | |
35 | ||
1da177e4 LT |
36 | LIST_HEAD(super_blocks); |
37 | DEFINE_SPINLOCK(sb_lock); | |
38 | ||
39 | /** | |
40 | * alloc_super - create new superblock | |
fe2bbc48 | 41 | * @type: filesystem type superblock should belong to |
1da177e4 LT |
42 | * |
43 | * Allocates and initializes a new &struct super_block. alloc_super() | |
44 | * returns a pointer new superblock or %NULL if allocation had failed. | |
45 | */ | |
cf516249 | 46 | static struct super_block *alloc_super(struct file_system_type *type) |
1da177e4 | 47 | { |
11b0b5ab | 48 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
b87221de | 49 | static const struct super_operations default_op; |
1da177e4 LT |
50 | |
51 | if (s) { | |
1da177e4 LT |
52 | if (security_sb_alloc(s)) { |
53 | kfree(s); | |
54 | s = NULL; | |
55 | goto out; | |
56 | } | |
1da177e4 LT |
57 | INIT_LIST_HEAD(&s->s_files); |
58 | INIT_LIST_HEAD(&s->s_instances); | |
59 | INIT_HLIST_HEAD(&s->s_anon); | |
60 | INIT_LIST_HEAD(&s->s_inodes); | |
da3bbdd4 | 61 | INIT_LIST_HEAD(&s->s_dentry_lru); |
1da177e4 | 62 | init_rwsem(&s->s_umount); |
7892f2f4 | 63 | mutex_init(&s->s_lock); |
897c6ff9 | 64 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
cf516249 IM |
65 | /* |
66 | * The locking rules for s_lock are up to the | |
67 | * filesystem. For example ext3fs has different | |
68 | * lock ordering than usbfs: | |
69 | */ | |
70 | lockdep_set_class(&s->s_lock, &type->s_lock_key); | |
ada723dc PZ |
71 | /* |
72 | * sget() can have s_umount recursion. | |
73 | * | |
74 | * When it cannot find a suitable sb, it allocates a new | |
75 | * one (this one), and tries again to find a suitable old | |
76 | * one. | |
77 | * | |
78 | * In case that succeeds, it will acquire the s_umount | |
79 | * lock of the old one. Since these are clearly distrinct | |
80 | * locks, and this object isn't exposed yet, there's no | |
81 | * risk of deadlocks. | |
82 | * | |
83 | * Annotate this by putting this lock in a different | |
84 | * subclass. | |
85 | */ | |
86 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); | |
b20bd1a5 | 87 | s->s_count = 1; |
1da177e4 | 88 | atomic_set(&s->s_active, 1); |
a11f3a05 | 89 | mutex_init(&s->s_vfs_rename_mutex); |
51ee049e | 90 | lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key); |
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; | |
1da177e4 LT |
96 | s->s_op = &default_op; |
97 | s->s_time_gran = 1000000000; | |
98 | } | |
99 | out: | |
100 | return s; | |
101 | } | |
102 | ||
103 | /** | |
104 | * destroy_super - frees a superblock | |
105 | * @s: superblock to free | |
106 | * | |
107 | * Frees a superblock. | |
108 | */ | |
109 | static inline void destroy_super(struct super_block *s) | |
110 | { | |
111 | security_sb_free(s); | |
79c0b2df | 112 | kfree(s->s_subtype); |
b3b304a2 | 113 | kfree(s->s_options); |
1da177e4 LT |
114 | kfree(s); |
115 | } | |
116 | ||
117 | /* Superblock refcounting */ | |
118 | ||
119 | /* | |
35cf7ba0 | 120 | * Drop a superblock's refcount. The caller must hold sb_lock. |
1da177e4 | 121 | */ |
35cf7ba0 | 122 | void __put_super(struct super_block *sb) |
1da177e4 | 123 | { |
1da177e4 | 124 | if (!--sb->s_count) { |
551de6f3 | 125 | list_del_init(&sb->s_list); |
1da177e4 | 126 | destroy_super(sb); |
1da177e4 | 127 | } |
1da177e4 LT |
128 | } |
129 | ||
130 | /** | |
131 | * put_super - drop a temporary reference to superblock | |
132 | * @sb: superblock in question | |
133 | * | |
134 | * Drops a temporary reference, frees superblock if there's no | |
135 | * references left. | |
136 | */ | |
03ba3782 | 137 | void put_super(struct super_block *sb) |
1da177e4 LT |
138 | { |
139 | spin_lock(&sb_lock); | |
140 | __put_super(sb); | |
141 | spin_unlock(&sb_lock); | |
142 | } | |
143 | ||
144 | ||
145 | /** | |
1712ac8f | 146 | * deactivate_locked_super - drop an active reference to superblock |
1da177e4 LT |
147 | * @s: superblock to deactivate |
148 | * | |
1712ac8f AV |
149 | * Drops an active reference to superblock, converting it into a temprory |
150 | * one if there is no other active references left. In that case we | |
1da177e4 LT |
151 | * tell fs driver to shut it down and drop the temporary reference we |
152 | * had just acquired. | |
1712ac8f AV |
153 | * |
154 | * Caller holds exclusive lock on superblock; that lock is released. | |
1da177e4 | 155 | */ |
1712ac8f | 156 | void deactivate_locked_super(struct super_block *s) |
1da177e4 LT |
157 | { |
158 | struct file_system_type *fs = s->s_type; | |
b20bd1a5 | 159 | if (atomic_dec_and_test(&s->s_active)) { |
1da177e4 LT |
160 | fs->kill_sb(s); |
161 | put_filesystem(fs); | |
162 | put_super(s); | |
1712ac8f AV |
163 | } else { |
164 | up_write(&s->s_umount); | |
1da177e4 LT |
165 | } |
166 | } | |
167 | ||
1712ac8f | 168 | EXPORT_SYMBOL(deactivate_locked_super); |
1da177e4 | 169 | |
74dbbdd7 | 170 | /** |
1712ac8f | 171 | * deactivate_super - drop an active reference to superblock |
74dbbdd7 AV |
172 | * @s: superblock to deactivate |
173 | * | |
1712ac8f AV |
174 | * Variant of deactivate_locked_super(), except that superblock is *not* |
175 | * locked by caller. If we are going to drop the final active reference, | |
176 | * lock will be acquired prior to that. | |
74dbbdd7 | 177 | */ |
1712ac8f | 178 | void deactivate_super(struct super_block *s) |
74dbbdd7 | 179 | { |
1712ac8f AV |
180 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
181 | down_write(&s->s_umount); | |
182 | deactivate_locked_super(s); | |
74dbbdd7 AV |
183 | } |
184 | } | |
185 | ||
1712ac8f | 186 | EXPORT_SYMBOL(deactivate_super); |
74dbbdd7 | 187 | |
1da177e4 LT |
188 | /** |
189 | * grab_super - acquire an active reference | |
190 | * @s: reference we are trying to make active | |
191 | * | |
192 | * Tries to acquire an active reference. grab_super() is used when we | |
193 | * had just found a superblock in super_blocks or fs_type->fs_supers | |
194 | * and want to turn it into a full-blown active reference. grab_super() | |
195 | * is called with sb_lock held and drops it. Returns 1 in case of | |
196 | * success, 0 if we had failed (superblock contents was already dead or | |
197 | * dying when grab_super() had been called). | |
198 | */ | |
9c4dbee7 | 199 | static int grab_super(struct super_block *s) __releases(sb_lock) |
1da177e4 | 200 | { |
b20bd1a5 AV |
201 | if (atomic_inc_not_zero(&s->s_active)) { |
202 | spin_unlock(&sb_lock); | |
b20bd1a5 AV |
203 | return 1; |
204 | } | |
205 | /* it's going away */ | |
1da177e4 LT |
206 | s->s_count++; |
207 | spin_unlock(&sb_lock); | |
1712ac8f | 208 | /* wait for it to die */ |
1da177e4 | 209 | down_write(&s->s_umount); |
1da177e4 LT |
210 | up_write(&s->s_umount); |
211 | put_super(s); | |
1da177e4 LT |
212 | return 0; |
213 | } | |
214 | ||
914e2637 AV |
215 | /* |
216 | * Superblock locking. We really ought to get rid of these two. | |
217 | */ | |
218 | void lock_super(struct super_block * sb) | |
219 | { | |
220 | get_fs_excl(); | |
221 | mutex_lock(&sb->s_lock); | |
222 | } | |
223 | ||
224 | void unlock_super(struct super_block * sb) | |
225 | { | |
226 | put_fs_excl(); | |
227 | mutex_unlock(&sb->s_lock); | |
228 | } | |
229 | ||
230 | EXPORT_SYMBOL(lock_super); | |
231 | EXPORT_SYMBOL(unlock_super); | |
232 | ||
1da177e4 LT |
233 | /** |
234 | * generic_shutdown_super - common helper for ->kill_sb() | |
235 | * @sb: superblock to kill | |
236 | * | |
237 | * generic_shutdown_super() does all fs-independent work on superblock | |
238 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects | |
239 | * that need destruction out of superblock, call generic_shutdown_super() | |
240 | * and release aforementioned objects. Note: dentries and inodes _are_ | |
241 | * taken care of and do not need specific handling. | |
c636ebdb DH |
242 | * |
243 | * Upon calling this function, the filesystem may no longer alter or | |
244 | * rearrange the set of dentries belonging to this super_block, nor may it | |
245 | * change the attachments of dentries to inodes. | |
1da177e4 LT |
246 | */ |
247 | void generic_shutdown_super(struct super_block *sb) | |
248 | { | |
ee9b6d61 | 249 | const struct super_operations *sop = sb->s_op; |
1da177e4 | 250 | |
efaee192 | 251 | |
c636ebdb DH |
252 | if (sb->s_root) { |
253 | shrink_dcache_for_umount(sb); | |
60b0680f | 254 | sync_filesystem(sb); |
a9e220f8 | 255 | get_fs_excl(); |
1da177e4 | 256 | sb->s_flags &= ~MS_ACTIVE; |
efaee192 | 257 | |
1da177e4 LT |
258 | /* bad name - it should be evict_inodes() */ |
259 | invalidate_inodes(sb); | |
1da177e4 | 260 | |
1da177e4 LT |
261 | if (sop->put_super) |
262 | sop->put_super(sb); | |
263 | ||
264 | /* Forget any remaining inodes */ | |
265 | if (invalidate_inodes(sb)) { | |
7b4fe29e DJ |
266 | printk("VFS: Busy inodes after unmount of %s. " |
267 | "Self-destruct in 5 seconds. Have a nice day...\n", | |
268 | sb->s_id); | |
1da177e4 | 269 | } |
a9e220f8 | 270 | put_fs_excl(); |
1da177e4 LT |
271 | } |
272 | spin_lock(&sb_lock); | |
273 | /* should be initialized for __put_super_and_need_restart() */ | |
551de6f3 | 274 | list_del_init(&sb->s_instances); |
1da177e4 LT |
275 | spin_unlock(&sb_lock); |
276 | up_write(&sb->s_umount); | |
277 | } | |
278 | ||
279 | EXPORT_SYMBOL(generic_shutdown_super); | |
280 | ||
281 | /** | |
282 | * sget - find or create a superblock | |
283 | * @type: filesystem type superblock should belong to | |
284 | * @test: comparison callback | |
285 | * @set: setup callback | |
286 | * @data: argument to each of them | |
287 | */ | |
288 | struct super_block *sget(struct file_system_type *type, | |
289 | int (*test)(struct super_block *,void *), | |
290 | int (*set)(struct super_block *,void *), | |
291 | void *data) | |
292 | { | |
293 | struct super_block *s = NULL; | |
d4730127 | 294 | struct super_block *old; |
1da177e4 LT |
295 | int err; |
296 | ||
297 | retry: | |
298 | spin_lock(&sb_lock); | |
d4730127 MK |
299 | if (test) { |
300 | list_for_each_entry(old, &type->fs_supers, s_instances) { | |
301 | if (!test(old, data)) | |
302 | continue; | |
303 | if (!grab_super(old)) | |
304 | goto retry; | |
a3cfbb53 LZ |
305 | if (s) { |
306 | up_write(&s->s_umount); | |
d4730127 | 307 | destroy_super(s); |
a3cfbb53 | 308 | } |
d3f21473 | 309 | down_write(&old->s_umount); |
d4730127 MK |
310 | return old; |
311 | } | |
1da177e4 LT |
312 | } |
313 | if (!s) { | |
314 | spin_unlock(&sb_lock); | |
cf516249 | 315 | s = alloc_super(type); |
1da177e4 LT |
316 | if (!s) |
317 | return ERR_PTR(-ENOMEM); | |
318 | goto retry; | |
319 | } | |
320 | ||
321 | err = set(s, data); | |
322 | if (err) { | |
323 | spin_unlock(&sb_lock); | |
a3cfbb53 | 324 | up_write(&s->s_umount); |
1da177e4 LT |
325 | destroy_super(s); |
326 | return ERR_PTR(err); | |
327 | } | |
328 | s->s_type = type; | |
329 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
330 | list_add_tail(&s->s_list, &super_blocks); | |
331 | list_add(&s->s_instances, &type->fs_supers); | |
332 | spin_unlock(&sb_lock); | |
333 | get_filesystem(type); | |
334 | return s; | |
335 | } | |
336 | ||
337 | EXPORT_SYMBOL(sget); | |
338 | ||
339 | void drop_super(struct super_block *sb) | |
340 | { | |
341 | up_read(&sb->s_umount); | |
342 | put_super(sb); | |
343 | } | |
344 | ||
345 | EXPORT_SYMBOL(drop_super); | |
346 | ||
e5004753 CH |
347 | /** |
348 | * sync_supers - helper for periodic superblock writeback | |
349 | * | |
350 | * Call the write_super method if present on all dirty superblocks in | |
351 | * the system. This is for the periodic writeback used by most older | |
352 | * filesystems. For data integrity superblock writeback use | |
353 | * sync_filesystems() instead. | |
354 | * | |
1da177e4 LT |
355 | * Note: check the dirty flag before waiting, so we don't |
356 | * hold up the sync while mounting a device. (The newly | |
357 | * mounted device won't need syncing.) | |
358 | */ | |
359 | void sync_supers(void) | |
360 | { | |
6754af64 | 361 | struct super_block *sb, *n; |
618f0636 | 362 | |
1da177e4 | 363 | spin_lock(&sb_lock); |
6754af64 | 364 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { |
551de6f3 AV |
365 | if (list_empty(&sb->s_instances)) |
366 | continue; | |
e5004753 | 367 | if (sb->s_op->write_super && sb->s_dirt) { |
1da177e4 LT |
368 | sb->s_count++; |
369 | spin_unlock(&sb_lock); | |
e5004753 | 370 | |
1da177e4 | 371 | down_read(&sb->s_umount); |
e5004753 CH |
372 | if (sb->s_root && sb->s_dirt) |
373 | sb->s_op->write_super(sb); | |
618f0636 | 374 | up_read(&sb->s_umount); |
e5004753 | 375 | |
618f0636 | 376 | spin_lock(&sb_lock); |
57439f87 | 377 | /* lock was dropped, must reset next */ |
378 | list_safe_reset_next(sb, n, s_list); | |
6754af64 | 379 | __put_super(sb); |
618f0636 KK |
380 | } |
381 | } | |
1da177e4 LT |
382 | spin_unlock(&sb_lock); |
383 | } | |
384 | ||
01a05b33 AV |
385 | /** |
386 | * iterate_supers - call function for all active superblocks | |
387 | * @f: function to call | |
388 | * @arg: argument to pass to it | |
389 | * | |
390 | * Scans the superblock list and calls given function, passing it | |
391 | * locked superblock and given argument. | |
392 | */ | |
393 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) | |
394 | { | |
395 | struct super_block *sb, *n; | |
396 | ||
397 | spin_lock(&sb_lock); | |
398 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { | |
399 | if (list_empty(&sb->s_instances)) | |
400 | continue; | |
401 | sb->s_count++; | |
402 | spin_unlock(&sb_lock); | |
403 | ||
404 | down_read(&sb->s_umount); | |
405 | if (sb->s_root) | |
406 | f(sb, arg); | |
407 | up_read(&sb->s_umount); | |
408 | ||
409 | spin_lock(&sb_lock); | |
57439f87 | 410 | /* lock was dropped, must reset next */ |
411 | list_safe_reset_next(sb, n, s_list); | |
01a05b33 AV |
412 | __put_super(sb); |
413 | } | |
414 | spin_unlock(&sb_lock); | |
415 | } | |
416 | ||
1da177e4 LT |
417 | /** |
418 | * get_super - get the superblock of a device | |
419 | * @bdev: device to get the superblock for | |
420 | * | |
421 | * Scans the superblock list and finds the superblock of the file system | |
422 | * mounted on the device given. %NULL is returned if no match is found. | |
423 | */ | |
424 | ||
df40c01a | 425 | struct super_block *get_super(struct block_device *bdev) |
1da177e4 | 426 | { |
618f0636 KK |
427 | struct super_block *sb; |
428 | ||
1da177e4 LT |
429 | if (!bdev) |
430 | return NULL; | |
618f0636 | 431 | |
1da177e4 | 432 | spin_lock(&sb_lock); |
618f0636 KK |
433 | rescan: |
434 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
435 | if (list_empty(&sb->s_instances)) |
436 | continue; | |
618f0636 KK |
437 | if (sb->s_bdev == bdev) { |
438 | sb->s_count++; | |
1da177e4 | 439 | spin_unlock(&sb_lock); |
618f0636 | 440 | down_read(&sb->s_umount); |
df40c01a | 441 | /* still alive? */ |
618f0636 KK |
442 | if (sb->s_root) |
443 | return sb; | |
444 | up_read(&sb->s_umount); | |
df40c01a | 445 | /* nope, got unmounted */ |
618f0636 | 446 | spin_lock(&sb_lock); |
df40c01a AV |
447 | __put_super(sb); |
448 | goto rescan; | |
1da177e4 LT |
449 | } |
450 | } | |
451 | spin_unlock(&sb_lock); | |
452 | return NULL; | |
453 | } | |
454 | ||
455 | EXPORT_SYMBOL(get_super); | |
4504230a CH |
456 | |
457 | /** | |
458 | * get_active_super - get an active reference to the superblock of a device | |
459 | * @bdev: device to get the superblock for | |
460 | * | |
461 | * Scans the superblock list and finds the superblock of the file system | |
462 | * mounted on the device given. Returns the superblock with an active | |
d3f21473 | 463 | * reference or %NULL if none was found. |
4504230a CH |
464 | */ |
465 | struct super_block *get_active_super(struct block_device *bdev) | |
466 | { | |
467 | struct super_block *sb; | |
468 | ||
469 | if (!bdev) | |
470 | return NULL; | |
471 | ||
1494583d | 472 | restart: |
4504230a CH |
473 | spin_lock(&sb_lock); |
474 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
475 | if (list_empty(&sb->s_instances)) |
476 | continue; | |
1494583d AV |
477 | if (sb->s_bdev == bdev) { |
478 | if (grab_super(sb)) /* drops sb_lock */ | |
479 | return sb; | |
480 | else | |
481 | goto restart; | |
482 | } | |
4504230a CH |
483 | } |
484 | spin_unlock(&sb_lock); | |
485 | return NULL; | |
486 | } | |
1da177e4 | 487 | |
df40c01a | 488 | struct super_block *user_get_super(dev_t dev) |
1da177e4 | 489 | { |
618f0636 | 490 | struct super_block *sb; |
1da177e4 | 491 | |
1da177e4 | 492 | spin_lock(&sb_lock); |
618f0636 KK |
493 | rescan: |
494 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
495 | if (list_empty(&sb->s_instances)) |
496 | continue; | |
618f0636 KK |
497 | if (sb->s_dev == dev) { |
498 | sb->s_count++; | |
1da177e4 | 499 | spin_unlock(&sb_lock); |
618f0636 | 500 | down_read(&sb->s_umount); |
df40c01a | 501 | /* still alive? */ |
618f0636 KK |
502 | if (sb->s_root) |
503 | return sb; | |
504 | up_read(&sb->s_umount); | |
df40c01a | 505 | /* nope, got unmounted */ |
618f0636 | 506 | spin_lock(&sb_lock); |
df40c01a AV |
507 | __put_super(sb); |
508 | goto rescan; | |
1da177e4 LT |
509 | } |
510 | } | |
511 | spin_unlock(&sb_lock); | |
512 | return NULL; | |
513 | } | |
514 | ||
1da177e4 LT |
515 | /** |
516 | * do_remount_sb - asks filesystem to change mount options. | |
517 | * @sb: superblock in question | |
518 | * @flags: numeric part of options | |
519 | * @data: the rest of options | |
520 | * @force: whether or not to force the change | |
521 | * | |
522 | * Alters the mount options of a mounted file system. | |
523 | */ | |
524 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
525 | { | |
526 | int retval; | |
c79d967d | 527 | int remount_ro; |
4504230a CH |
528 | |
529 | if (sb->s_frozen != SB_UNFROZEN) | |
530 | return -EBUSY; | |
531 | ||
9361401e | 532 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
533 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
534 | return -EACCES; | |
9361401e | 535 | #endif |
4504230a | 536 | |
1da177e4 LT |
537 | if (flags & MS_RDONLY) |
538 | acct_auto_close(sb); | |
539 | shrink_dcache_sb(sb); | |
60b0680f | 540 | sync_filesystem(sb); |
1da177e4 | 541 | |
d208bbdd | 542 | remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); |
d208bbdd | 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 LT |
550 | return -EBUSY; |
551 | } | |
552 | ||
553 | if (sb->s_op->remount_fs) { | |
1da177e4 | 554 | retval = sb->s_op->remount_fs(sb, &flags, data); |
b0895513 | 555 | if (retval) |
1da177e4 LT |
556 | return retval; |
557 | } | |
558 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
c79d967d | 559 | |
d208bbdd NP |
560 | /* |
561 | * Some filesystems modify their metadata via some other path than the | |
562 | * bdev buffer cache (eg. use a private mapping, or directories in | |
563 | * pagecache, etc). Also file data modifications go via their own | |
564 | * mappings. So If we try to mount readonly then copy the filesystem | |
565 | * from bdev, we could get stale data, so invalidate it to give a best | |
566 | * effort at coherency. | |
567 | */ | |
568 | if (remount_ro && sb->s_bdev) | |
569 | invalidate_bdev(sb->s_bdev); | |
1da177e4 LT |
570 | return 0; |
571 | } | |
572 | ||
a2a9537a | 573 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 | 574 | { |
e7fe0585 | 575 | struct super_block *sb, *n; |
1da177e4 LT |
576 | |
577 | spin_lock(&sb_lock); | |
e7fe0585 | 578 | list_for_each_entry_safe(sb, n, &super_blocks, s_list) { |
551de6f3 AV |
579 | if (list_empty(&sb->s_instances)) |
580 | continue; | |
1da177e4 LT |
581 | sb->s_count++; |
582 | spin_unlock(&sb_lock); | |
443b94ba | 583 | down_write(&sb->s_umount); |
1da177e4 LT |
584 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
585 | /* | |
1da177e4 LT |
586 | * What lock protects sb->s_flags?? |
587 | */ | |
1da177e4 | 588 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
1da177e4 | 589 | } |
443b94ba | 590 | up_write(&sb->s_umount); |
1da177e4 | 591 | spin_lock(&sb_lock); |
57439f87 | 592 | /* lock was dropped, must reset next */ |
593 | list_safe_reset_next(sb, n, s_list); | |
e7fe0585 | 594 | __put_super(sb); |
1da177e4 LT |
595 | } |
596 | spin_unlock(&sb_lock); | |
a2a9537a | 597 | kfree(work); |
1da177e4 LT |
598 | printk("Emergency Remount complete\n"); |
599 | } | |
600 | ||
601 | void emergency_remount(void) | |
602 | { | |
a2a9537a JA |
603 | struct work_struct *work; |
604 | ||
605 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
606 | if (work) { | |
607 | INIT_WORK(work, do_emergency_remount); | |
608 | schedule_work(work); | |
609 | } | |
1da177e4 LT |
610 | } |
611 | ||
612 | /* | |
613 | * Unnamed block devices are dummy devices used by virtual | |
614 | * filesystems which don't use real block-devices. -- jrs | |
615 | */ | |
616 | ||
ad76cbc6 | 617 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 | 618 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
c63e09ec | 619 | static int unnamed_dev_start = 0; /* don't bother trying below it */ |
1da177e4 LT |
620 | |
621 | int set_anon_super(struct super_block *s, void *data) | |
622 | { | |
623 | int dev; | |
624 | int error; | |
625 | ||
626 | retry: | |
ad76cbc6 | 627 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
628 | return -ENOMEM; |
629 | spin_lock(&unnamed_dev_lock); | |
c63e09ec | 630 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
f21f6220 AV |
631 | if (!error) |
632 | unnamed_dev_start = dev + 1; | |
1da177e4 LT |
633 | spin_unlock(&unnamed_dev_lock); |
634 | if (error == -EAGAIN) | |
635 | /* We raced and lost with another CPU. */ | |
636 | goto retry; | |
637 | else if (error) | |
638 | return -EAGAIN; | |
639 | ||
640 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
641 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 642 | ida_remove(&unnamed_dev_ida, dev); |
f21f6220 AV |
643 | if (unnamed_dev_start > dev) |
644 | unnamed_dev_start = dev; | |
1da177e4 LT |
645 | spin_unlock(&unnamed_dev_lock); |
646 | return -EMFILE; | |
647 | } | |
648 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
5129a469 | 649 | s->s_bdi = &noop_backing_dev_info; |
1da177e4 LT |
650 | return 0; |
651 | } | |
652 | ||
653 | EXPORT_SYMBOL(set_anon_super); | |
654 | ||
655 | void kill_anon_super(struct super_block *sb) | |
656 | { | |
657 | int slot = MINOR(sb->s_dev); | |
658 | ||
659 | generic_shutdown_super(sb); | |
660 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 661 | ida_remove(&unnamed_dev_ida, slot); |
c63e09ec AV |
662 | if (slot < unnamed_dev_start) |
663 | unnamed_dev_start = slot; | |
1da177e4 LT |
664 | spin_unlock(&unnamed_dev_lock); |
665 | } | |
666 | ||
667 | EXPORT_SYMBOL(kill_anon_super); | |
668 | ||
1da177e4 LT |
669 | void kill_litter_super(struct super_block *sb) |
670 | { | |
671 | if (sb->s_root) | |
672 | d_genocide(sb->s_root); | |
673 | kill_anon_super(sb); | |
674 | } | |
675 | ||
676 | EXPORT_SYMBOL(kill_litter_super); | |
677 | ||
909e6d94 SH |
678 | static int ns_test_super(struct super_block *sb, void *data) |
679 | { | |
680 | return sb->s_fs_info == data; | |
681 | } | |
682 | ||
683 | static int ns_set_super(struct super_block *sb, void *data) | |
684 | { | |
685 | sb->s_fs_info = data; | |
686 | return set_anon_super(sb, NULL); | |
687 | } | |
688 | ||
689 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
690 | int (*fill_super)(struct super_block *, void *, int), | |
691 | struct vfsmount *mnt) | |
692 | { | |
693 | struct super_block *sb; | |
694 | ||
695 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
696 | if (IS_ERR(sb)) | |
697 | return PTR_ERR(sb); | |
698 | ||
699 | if (!sb->s_root) { | |
700 | int err; | |
701 | sb->s_flags = flags; | |
702 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
703 | if (err) { | |
74dbbdd7 | 704 | deactivate_locked_super(sb); |
909e6d94 SH |
705 | return err; |
706 | } | |
707 | ||
708 | sb->s_flags |= MS_ACTIVE; | |
709 | } | |
710 | ||
711 | simple_set_mnt(mnt, sb); | |
712 | return 0; | |
713 | } | |
714 | ||
715 | EXPORT_SYMBOL(get_sb_ns); | |
716 | ||
9361401e | 717 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
718 | static int set_bdev_super(struct super_block *s, void *data) |
719 | { | |
720 | s->s_bdev = data; | |
721 | s->s_dev = s->s_bdev->bd_dev; | |
32a88aa1 JA |
722 | |
723 | /* | |
724 | * We set the bdi here to the queue backing, file systems can | |
725 | * overwrite this in ->fill_super() | |
726 | */ | |
727 | s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info; | |
1da177e4 LT |
728 | return 0; |
729 | } | |
730 | ||
731 | static int test_bdev_super(struct super_block *s, void *data) | |
732 | { | |
733 | return (void *)s->s_bdev == data; | |
734 | } | |
735 | ||
454e2398 | 736 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 737 | int flags, const char *dev_name, void *data, |
454e2398 DH |
738 | int (*fill_super)(struct super_block *, void *, int), |
739 | struct vfsmount *mnt) | |
1da177e4 LT |
740 | { |
741 | struct block_device *bdev; | |
742 | struct super_block *s; | |
30c40d2c | 743 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
744 | int error = 0; |
745 | ||
30c40d2c AV |
746 | if (!(flags & MS_RDONLY)) |
747 | mode |= FMODE_WRITE; | |
748 | ||
749 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 750 | if (IS_ERR(bdev)) |
454e2398 | 751 | return PTR_ERR(bdev); |
1da177e4 LT |
752 | |
753 | /* | |
754 | * once the super is inserted into the list by sget, s_umount | |
755 | * will protect the lockfs code from trying to start a snapshot | |
756 | * while we are mounting | |
757 | */ | |
4fadd7bb CH |
758 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
759 | if (bdev->bd_fsfreeze_count > 0) { | |
760 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
761 | error = -EBUSY; | |
762 | goto error_bdev; | |
763 | } | |
1da177e4 | 764 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
4fadd7bb | 765 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
1da177e4 | 766 | if (IS_ERR(s)) |
454e2398 | 767 | goto error_s; |
1da177e4 LT |
768 | |
769 | if (s->s_root) { | |
770 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 771 | deactivate_locked_super(s); |
454e2398 DH |
772 | error = -EBUSY; |
773 | goto error_bdev; | |
1da177e4 | 774 | } |
454e2398 | 775 | |
30c40d2c | 776 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
777 | } else { |
778 | char b[BDEVNAME_SIZE]; | |
779 | ||
780 | s->s_flags = flags; | |
30c40d2c | 781 | s->s_mode = mode; |
1da177e4 | 782 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 783 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 784 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 785 | if (error) { |
74dbbdd7 | 786 | deactivate_locked_super(s); |
454e2398 | 787 | goto error; |
fa675765 | 788 | } |
454e2398 DH |
789 | |
790 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 791 | bdev->bd_super = s; |
1da177e4 LT |
792 | } |
793 | ||
a3ec947c SB |
794 | simple_set_mnt(mnt, s); |
795 | return 0; | |
1da177e4 | 796 | |
454e2398 DH |
797 | error_s: |
798 | error = PTR_ERR(s); | |
799 | error_bdev: | |
30c40d2c | 800 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
801 | error: |
802 | return error; | |
1da177e4 LT |
803 | } |
804 | ||
805 | EXPORT_SYMBOL(get_sb_bdev); | |
806 | ||
807 | void kill_block_super(struct super_block *sb) | |
808 | { | |
809 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 810 | fmode_t mode = sb->s_mode; |
1da177e4 | 811 | |
ddbaaf30 | 812 | bdev->bd_super = NULL; |
1da177e4 LT |
813 | generic_shutdown_super(sb); |
814 | sync_blockdev(bdev); | |
30c40d2c | 815 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
816 | } |
817 | ||
818 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 819 | #endif |
1da177e4 | 820 | |
454e2398 | 821 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 822 | int flags, void *data, |
454e2398 DH |
823 | int (*fill_super)(struct super_block *, void *, int), |
824 | struct vfsmount *mnt) | |
1da177e4 LT |
825 | { |
826 | int error; | |
827 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
828 | ||
829 | if (IS_ERR(s)) | |
454e2398 | 830 | return PTR_ERR(s); |
1da177e4 LT |
831 | |
832 | s->s_flags = flags; | |
833 | ||
9b04c997 | 834 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 835 | if (error) { |
74dbbdd7 | 836 | deactivate_locked_super(s); |
454e2398 | 837 | return error; |
1da177e4 LT |
838 | } |
839 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
840 | simple_set_mnt(mnt, s); |
841 | return 0; | |
1da177e4 LT |
842 | } |
843 | ||
844 | EXPORT_SYMBOL(get_sb_nodev); | |
845 | ||
846 | static int compare_single(struct super_block *s, void *p) | |
847 | { | |
848 | return 1; | |
849 | } | |
850 | ||
454e2398 | 851 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 852 | int flags, void *data, |
454e2398 DH |
853 | int (*fill_super)(struct super_block *, void *, int), |
854 | struct vfsmount *mnt) | |
1da177e4 LT |
855 | { |
856 | struct super_block *s; | |
857 | int error; | |
858 | ||
859 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
860 | if (IS_ERR(s)) | |
454e2398 | 861 | return PTR_ERR(s); |
1da177e4 LT |
862 | if (!s->s_root) { |
863 | s->s_flags = flags; | |
9b04c997 | 864 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 865 | if (error) { |
74dbbdd7 | 866 | deactivate_locked_super(s); |
454e2398 | 867 | return error; |
1da177e4 LT |
868 | } |
869 | s->s_flags |= MS_ACTIVE; | |
9329d1be KS |
870 | } else { |
871 | do_remount_sb(s, flags, data, 0); | |
1da177e4 | 872 | } |
a3ec947c SB |
873 | simple_set_mnt(mnt, s); |
874 | return 0; | |
1da177e4 LT |
875 | } |
876 | ||
877 | EXPORT_SYMBOL(get_sb_single); | |
878 | ||
879 | struct vfsmount * | |
bb4a58bf | 880 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 881 | { |
1da177e4 | 882 | struct vfsmount *mnt; |
1da177e4 | 883 | char *secdata = NULL; |
454e2398 | 884 | int error; |
1da177e4 LT |
885 | |
886 | if (!type) | |
887 | return ERR_PTR(-ENODEV); | |
1da177e4 | 888 | |
454e2398 | 889 | error = -ENOMEM; |
1da177e4 LT |
890 | mnt = alloc_vfsmnt(name); |
891 | if (!mnt) | |
892 | goto out; | |
893 | ||
8089352a AV |
894 | if (flags & MS_KERNMOUNT) |
895 | mnt->mnt_flags = MNT_INTERNAL; | |
896 | ||
e0007529 | 897 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 898 | secdata = alloc_secdata(); |
454e2398 | 899 | if (!secdata) |
1da177e4 | 900 | goto out_mnt; |
1da177e4 | 901 | |
e0007529 | 902 | error = security_sb_copy_data(data, secdata); |
454e2398 | 903 | if (error) |
1da177e4 | 904 | goto out_free_secdata; |
1da177e4 LT |
905 | } |
906 | ||
454e2398 DH |
907 | error = type->get_sb(type, flags, name, data, mnt); |
908 | if (error < 0) | |
1da177e4 | 909 | goto out_free_secdata; |
b4c07bce | 910 | BUG_ON(!mnt->mnt_sb); |
5129a469 | 911 | WARN_ON(!mnt->mnt_sb->s_bdi); |
454e2398 | 912 | |
5129a469 JE |
913 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
914 | if (error) | |
915 | goto out_sb; | |
454e2398 | 916 | |
42cb56ae JL |
917 | /* |
918 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE | |
919 | * but s_maxbytes was an unsigned long long for many releases. Throw | |
920 | * this warning for a little while to try and catch filesystems that | |
921 | * violate this rule. This warning should be either removed or | |
922 | * converted to a BUG() in 2.6.34. | |
923 | */ | |
924 | WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " | |
925 | "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes); | |
926 | ||
454e2398 | 927 | mnt->mnt_mountpoint = mnt->mnt_root; |
1da177e4 | 928 | mnt->mnt_parent = mnt; |
454e2398 | 929 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 930 | free_secdata(secdata); |
1da177e4 LT |
931 | return mnt; |
932 | out_sb: | |
454e2398 | 933 | dput(mnt->mnt_root); |
74dbbdd7 | 934 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
935 | out_free_secdata: |
936 | free_secdata(secdata); | |
937 | out_mnt: | |
938 | free_vfsmnt(mnt); | |
939 | out: | |
454e2398 | 940 | return ERR_PTR(error); |
1da177e4 LT |
941 | } |
942 | ||
bb4a58bf TM |
943 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
944 | ||
18e9e510 | 945 | /** |
7000d3c4 RD |
946 | * freeze_super - lock the filesystem and force it into a consistent state |
947 | * @sb: the super to lock | |
18e9e510 JB |
948 | * |
949 | * Syncs the super to make sure the filesystem is consistent and calls the fs's | |
950 | * freeze_fs. Subsequent calls to this without first thawing the fs will return | |
951 | * -EBUSY. | |
952 | */ | |
953 | int freeze_super(struct super_block *sb) | |
954 | { | |
955 | int ret; | |
956 | ||
957 | atomic_inc(&sb->s_active); | |
958 | down_write(&sb->s_umount); | |
959 | if (sb->s_frozen) { | |
960 | deactivate_locked_super(sb); | |
961 | return -EBUSY; | |
962 | } | |
963 | ||
964 | if (sb->s_flags & MS_RDONLY) { | |
965 | sb->s_frozen = SB_FREEZE_TRANS; | |
966 | smp_wmb(); | |
967 | up_write(&sb->s_umount); | |
968 | return 0; | |
969 | } | |
970 | ||
971 | sb->s_frozen = SB_FREEZE_WRITE; | |
972 | smp_wmb(); | |
973 | ||
974 | sync_filesystem(sb); | |
975 | ||
976 | sb->s_frozen = SB_FREEZE_TRANS; | |
977 | smp_wmb(); | |
978 | ||
979 | sync_blockdev(sb->s_bdev); | |
980 | if (sb->s_op->freeze_fs) { | |
981 | ret = sb->s_op->freeze_fs(sb); | |
982 | if (ret) { | |
983 | printk(KERN_ERR | |
984 | "VFS:Filesystem freeze failed\n"); | |
985 | sb->s_frozen = SB_UNFROZEN; | |
986 | deactivate_locked_super(sb); | |
987 | return ret; | |
988 | } | |
989 | } | |
990 | up_write(&sb->s_umount); | |
991 | return 0; | |
992 | } | |
993 | EXPORT_SYMBOL(freeze_super); | |
994 | ||
995 | /** | |
996 | * thaw_super -- unlock filesystem | |
997 | * @sb: the super to thaw | |
998 | * | |
999 | * Unlocks the filesystem and marks it writeable again after freeze_super(). | |
1000 | */ | |
1001 | int thaw_super(struct super_block *sb) | |
1002 | { | |
1003 | int error; | |
1004 | ||
1005 | down_write(&sb->s_umount); | |
1006 | if (sb->s_frozen == SB_UNFROZEN) { | |
1007 | up_write(&sb->s_umount); | |
1008 | return -EINVAL; | |
1009 | } | |
1010 | ||
1011 | if (sb->s_flags & MS_RDONLY) | |
1012 | goto out; | |
1013 | ||
1014 | if (sb->s_op->unfreeze_fs) { | |
1015 | error = sb->s_op->unfreeze_fs(sb); | |
1016 | if (error) { | |
1017 | printk(KERN_ERR | |
1018 | "VFS:Filesystem thaw failed\n"); | |
1019 | sb->s_frozen = SB_FREEZE_TRANS; | |
1020 | up_write(&sb->s_umount); | |
1021 | return error; | |
1022 | } | |
1023 | } | |
1024 | ||
1025 | out: | |
1026 | sb->s_frozen = SB_UNFROZEN; | |
1027 | smp_wmb(); | |
1028 | wake_up(&sb->s_wait_unfrozen); | |
1029 | deactivate_locked_super(sb); | |
1030 | ||
1031 | return 0; | |
1032 | } | |
1033 | EXPORT_SYMBOL(thaw_super); | |
1034 | ||
79c0b2df MS |
1035 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
1036 | { | |
1037 | int err; | |
1038 | const char *subtype = strchr(fstype, '.'); | |
1039 | if (subtype) { | |
1040 | subtype++; | |
1041 | err = -EINVAL; | |
1042 | if (!subtype[0]) | |
1043 | goto err; | |
1044 | } else | |
1045 | subtype = ""; | |
1046 | ||
1047 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
1048 | err = -ENOMEM; | |
1049 | if (!mnt->mnt_sb->s_subtype) | |
1050 | goto err; | |
1051 | return mnt; | |
1052 | ||
1053 | err: | |
1054 | mntput(mnt); | |
1055 | return ERR_PTR(err); | |
1056 | } | |
1057 | ||
bb4a58bf TM |
1058 | struct vfsmount * |
1059 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
1060 | { | |
1061 | struct file_system_type *type = get_fs_type(fstype); | |
1062 | struct vfsmount *mnt; | |
1063 | if (!type) | |
1064 | return ERR_PTR(-ENODEV); | |
1065 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
1066 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
1067 | !mnt->mnt_sb->s_subtype) | |
1068 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
1069 | put_filesystem(type); |
1070 | return mnt; | |
1071 | } | |
8a4e98d9 | 1072 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 1073 | |
8bf9725c | 1074 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 1075 | { |
8bf9725c | 1076 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
1077 | } |
1078 | ||
8bf9725c | 1079 | EXPORT_SYMBOL_GPL(kern_mount_data); |