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); |
7a4dec53 | 308 | s = NULL; |
a3cfbb53 | 309 | } |
d3f21473 | 310 | down_write(&old->s_umount); |
7a4dec53 AV |
311 | if (unlikely(!(old->s_flags & MS_BORN))) { |
312 | deactivate_locked_super(old); | |
313 | goto retry; | |
314 | } | |
d4730127 MK |
315 | return old; |
316 | } | |
1da177e4 LT |
317 | } |
318 | if (!s) { | |
319 | spin_unlock(&sb_lock); | |
cf516249 | 320 | s = alloc_super(type); |
1da177e4 LT |
321 | if (!s) |
322 | return ERR_PTR(-ENOMEM); | |
323 | goto retry; | |
324 | } | |
325 | ||
326 | err = set(s, data); | |
327 | if (err) { | |
328 | spin_unlock(&sb_lock); | |
a3cfbb53 | 329 | up_write(&s->s_umount); |
1da177e4 LT |
330 | destroy_super(s); |
331 | return ERR_PTR(err); | |
332 | } | |
333 | s->s_type = type; | |
334 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
335 | list_add_tail(&s->s_list, &super_blocks); | |
336 | list_add(&s->s_instances, &type->fs_supers); | |
337 | spin_unlock(&sb_lock); | |
338 | get_filesystem(type); | |
339 | return s; | |
340 | } | |
341 | ||
342 | EXPORT_SYMBOL(sget); | |
343 | ||
344 | void drop_super(struct super_block *sb) | |
345 | { | |
346 | up_read(&sb->s_umount); | |
347 | put_super(sb); | |
348 | } | |
349 | ||
350 | EXPORT_SYMBOL(drop_super); | |
351 | ||
e5004753 CH |
352 | /** |
353 | * sync_supers - helper for periodic superblock writeback | |
354 | * | |
355 | * Call the write_super method if present on all dirty superblocks in | |
356 | * the system. This is for the periodic writeback used by most older | |
357 | * filesystems. For data integrity superblock writeback use | |
358 | * sync_filesystems() instead. | |
359 | * | |
1da177e4 LT |
360 | * Note: check the dirty flag before waiting, so we don't |
361 | * hold up the sync while mounting a device. (The newly | |
362 | * mounted device won't need syncing.) | |
363 | */ | |
364 | void sync_supers(void) | |
365 | { | |
dca33252 | 366 | struct super_block *sb, *p = NULL; |
618f0636 | 367 | |
1da177e4 | 368 | spin_lock(&sb_lock); |
dca33252 | 369 | list_for_each_entry(sb, &super_blocks, s_list) { |
551de6f3 AV |
370 | if (list_empty(&sb->s_instances)) |
371 | continue; | |
e5004753 | 372 | if (sb->s_op->write_super && sb->s_dirt) { |
1da177e4 LT |
373 | sb->s_count++; |
374 | spin_unlock(&sb_lock); | |
e5004753 | 375 | |
1da177e4 | 376 | down_read(&sb->s_umount); |
e5004753 CH |
377 | if (sb->s_root && sb->s_dirt) |
378 | sb->s_op->write_super(sb); | |
618f0636 | 379 | up_read(&sb->s_umount); |
e5004753 | 380 | |
618f0636 | 381 | spin_lock(&sb_lock); |
dca33252 AV |
382 | if (p) |
383 | __put_super(p); | |
384 | p = sb; | |
618f0636 KK |
385 | } |
386 | } | |
dca33252 AV |
387 | if (p) |
388 | __put_super(p); | |
1da177e4 LT |
389 | spin_unlock(&sb_lock); |
390 | } | |
391 | ||
01a05b33 AV |
392 | /** |
393 | * iterate_supers - call function for all active superblocks | |
394 | * @f: function to call | |
395 | * @arg: argument to pass to it | |
396 | * | |
397 | * Scans the superblock list and calls given function, passing it | |
398 | * locked superblock and given argument. | |
399 | */ | |
400 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) | |
401 | { | |
dca33252 | 402 | struct super_block *sb, *p = NULL; |
01a05b33 AV |
403 | |
404 | spin_lock(&sb_lock); | |
dca33252 | 405 | list_for_each_entry(sb, &super_blocks, s_list) { |
01a05b33 AV |
406 | if (list_empty(&sb->s_instances)) |
407 | continue; | |
408 | sb->s_count++; | |
409 | spin_unlock(&sb_lock); | |
410 | ||
411 | down_read(&sb->s_umount); | |
412 | if (sb->s_root) | |
413 | f(sb, arg); | |
414 | up_read(&sb->s_umount); | |
415 | ||
416 | spin_lock(&sb_lock); | |
dca33252 AV |
417 | if (p) |
418 | __put_super(p); | |
419 | p = sb; | |
01a05b33 | 420 | } |
dca33252 AV |
421 | if (p) |
422 | __put_super(p); | |
01a05b33 AV |
423 | spin_unlock(&sb_lock); |
424 | } | |
425 | ||
1da177e4 LT |
426 | /** |
427 | * get_super - get the superblock of a device | |
428 | * @bdev: device to get the superblock for | |
429 | * | |
430 | * Scans the superblock list and finds the superblock of the file system | |
431 | * mounted on the device given. %NULL is returned if no match is found. | |
432 | */ | |
433 | ||
df40c01a | 434 | struct super_block *get_super(struct block_device *bdev) |
1da177e4 | 435 | { |
618f0636 KK |
436 | struct super_block *sb; |
437 | ||
1da177e4 LT |
438 | if (!bdev) |
439 | return NULL; | |
618f0636 | 440 | |
1da177e4 | 441 | spin_lock(&sb_lock); |
618f0636 KK |
442 | rescan: |
443 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
444 | if (list_empty(&sb->s_instances)) |
445 | continue; | |
618f0636 KK |
446 | if (sb->s_bdev == bdev) { |
447 | sb->s_count++; | |
1da177e4 | 448 | spin_unlock(&sb_lock); |
618f0636 | 449 | down_read(&sb->s_umount); |
df40c01a | 450 | /* still alive? */ |
618f0636 KK |
451 | if (sb->s_root) |
452 | return sb; | |
453 | up_read(&sb->s_umount); | |
df40c01a | 454 | /* nope, got unmounted */ |
618f0636 | 455 | spin_lock(&sb_lock); |
df40c01a AV |
456 | __put_super(sb); |
457 | goto rescan; | |
1da177e4 LT |
458 | } |
459 | } | |
460 | spin_unlock(&sb_lock); | |
461 | return NULL; | |
462 | } | |
463 | ||
464 | EXPORT_SYMBOL(get_super); | |
4504230a CH |
465 | |
466 | /** | |
467 | * get_active_super - get an active reference to the superblock of a device | |
468 | * @bdev: device to get the superblock for | |
469 | * | |
470 | * Scans the superblock list and finds the superblock of the file system | |
471 | * mounted on the device given. Returns the superblock with an active | |
d3f21473 | 472 | * reference or %NULL if none was found. |
4504230a CH |
473 | */ |
474 | struct super_block *get_active_super(struct block_device *bdev) | |
475 | { | |
476 | struct super_block *sb; | |
477 | ||
478 | if (!bdev) | |
479 | return NULL; | |
480 | ||
1494583d | 481 | restart: |
4504230a CH |
482 | spin_lock(&sb_lock); |
483 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
484 | if (list_empty(&sb->s_instances)) |
485 | continue; | |
1494583d AV |
486 | if (sb->s_bdev == bdev) { |
487 | if (grab_super(sb)) /* drops sb_lock */ | |
488 | return sb; | |
489 | else | |
490 | goto restart; | |
491 | } | |
4504230a CH |
492 | } |
493 | spin_unlock(&sb_lock); | |
494 | return NULL; | |
495 | } | |
1da177e4 | 496 | |
df40c01a | 497 | struct super_block *user_get_super(dev_t dev) |
1da177e4 | 498 | { |
618f0636 | 499 | struct super_block *sb; |
1da177e4 | 500 | |
1da177e4 | 501 | spin_lock(&sb_lock); |
618f0636 KK |
502 | rescan: |
503 | list_for_each_entry(sb, &super_blocks, s_list) { | |
551de6f3 AV |
504 | if (list_empty(&sb->s_instances)) |
505 | continue; | |
618f0636 KK |
506 | if (sb->s_dev == dev) { |
507 | sb->s_count++; | |
1da177e4 | 508 | spin_unlock(&sb_lock); |
618f0636 | 509 | down_read(&sb->s_umount); |
df40c01a | 510 | /* still alive? */ |
618f0636 KK |
511 | if (sb->s_root) |
512 | return sb; | |
513 | up_read(&sb->s_umount); | |
df40c01a | 514 | /* nope, got unmounted */ |
618f0636 | 515 | spin_lock(&sb_lock); |
df40c01a AV |
516 | __put_super(sb); |
517 | goto rescan; | |
1da177e4 LT |
518 | } |
519 | } | |
520 | spin_unlock(&sb_lock); | |
521 | return NULL; | |
522 | } | |
523 | ||
1da177e4 LT |
524 | /** |
525 | * do_remount_sb - asks filesystem to change mount options. | |
526 | * @sb: superblock in question | |
527 | * @flags: numeric part of options | |
528 | * @data: the rest of options | |
529 | * @force: whether or not to force the change | |
530 | * | |
531 | * Alters the mount options of a mounted file system. | |
532 | */ | |
533 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
534 | { | |
535 | int retval; | |
c79d967d | 536 | int remount_ro; |
4504230a CH |
537 | |
538 | if (sb->s_frozen != SB_UNFROZEN) | |
539 | return -EBUSY; | |
540 | ||
9361401e | 541 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
542 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
543 | return -EACCES; | |
9361401e | 544 | #endif |
4504230a | 545 | |
1da177e4 LT |
546 | if (flags & MS_RDONLY) |
547 | acct_auto_close(sb); | |
548 | shrink_dcache_sb(sb); | |
60b0680f | 549 | sync_filesystem(sb); |
1da177e4 | 550 | |
d208bbdd | 551 | remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); |
d208bbdd | 552 | |
1da177e4 LT |
553 | /* If we are remounting RDONLY and current sb is read/write, |
554 | make sure there are no rw files opened */ | |
d208bbdd | 555 | if (remount_ro) { |
1da177e4 LT |
556 | if (force) |
557 | mark_files_ro(sb); | |
b0895513 | 558 | else if (!fs_may_remount_ro(sb)) |
1da177e4 LT |
559 | return -EBUSY; |
560 | } | |
561 | ||
562 | if (sb->s_op->remount_fs) { | |
1da177e4 | 563 | retval = sb->s_op->remount_fs(sb, &flags, data); |
b0895513 | 564 | if (retval) |
1da177e4 LT |
565 | return retval; |
566 | } | |
567 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
c79d967d | 568 | |
d208bbdd NP |
569 | /* |
570 | * Some filesystems modify their metadata via some other path than the | |
571 | * bdev buffer cache (eg. use a private mapping, or directories in | |
572 | * pagecache, etc). Also file data modifications go via their own | |
573 | * mappings. So If we try to mount readonly then copy the filesystem | |
574 | * from bdev, we could get stale data, so invalidate it to give a best | |
575 | * effort at coherency. | |
576 | */ | |
577 | if (remount_ro && sb->s_bdev) | |
578 | invalidate_bdev(sb->s_bdev); | |
1da177e4 LT |
579 | return 0; |
580 | } | |
581 | ||
a2a9537a | 582 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 | 583 | { |
dca33252 | 584 | struct super_block *sb, *p = NULL; |
1da177e4 LT |
585 | |
586 | spin_lock(&sb_lock); | |
dca33252 | 587 | list_for_each_entry(sb, &super_blocks, s_list) { |
551de6f3 AV |
588 | if (list_empty(&sb->s_instances)) |
589 | continue; | |
1da177e4 LT |
590 | sb->s_count++; |
591 | spin_unlock(&sb_lock); | |
443b94ba | 592 | down_write(&sb->s_umount); |
1da177e4 LT |
593 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
594 | /* | |
1da177e4 LT |
595 | * What lock protects sb->s_flags?? |
596 | */ | |
1da177e4 | 597 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
1da177e4 | 598 | } |
443b94ba | 599 | up_write(&sb->s_umount); |
1da177e4 | 600 | spin_lock(&sb_lock); |
dca33252 AV |
601 | if (p) |
602 | __put_super(p); | |
603 | p = sb; | |
1da177e4 | 604 | } |
dca33252 AV |
605 | if (p) |
606 | __put_super(p); | |
1da177e4 | 607 | spin_unlock(&sb_lock); |
a2a9537a | 608 | kfree(work); |
1da177e4 LT |
609 | printk("Emergency Remount complete\n"); |
610 | } | |
611 | ||
612 | void emergency_remount(void) | |
613 | { | |
a2a9537a JA |
614 | struct work_struct *work; |
615 | ||
616 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
617 | if (work) { | |
618 | INIT_WORK(work, do_emergency_remount); | |
619 | schedule_work(work); | |
620 | } | |
1da177e4 LT |
621 | } |
622 | ||
623 | /* | |
624 | * Unnamed block devices are dummy devices used by virtual | |
625 | * filesystems which don't use real block-devices. -- jrs | |
626 | */ | |
627 | ||
ad76cbc6 | 628 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 | 629 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
c63e09ec | 630 | static int unnamed_dev_start = 0; /* don't bother trying below it */ |
1da177e4 LT |
631 | |
632 | int set_anon_super(struct super_block *s, void *data) | |
633 | { | |
634 | int dev; | |
635 | int error; | |
636 | ||
637 | retry: | |
ad76cbc6 | 638 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
639 | return -ENOMEM; |
640 | spin_lock(&unnamed_dev_lock); | |
c63e09ec | 641 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
f21f6220 AV |
642 | if (!error) |
643 | unnamed_dev_start = dev + 1; | |
1da177e4 LT |
644 | spin_unlock(&unnamed_dev_lock); |
645 | if (error == -EAGAIN) | |
646 | /* We raced and lost with another CPU. */ | |
647 | goto retry; | |
648 | else if (error) | |
649 | return -EAGAIN; | |
650 | ||
651 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
652 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 653 | ida_remove(&unnamed_dev_ida, dev); |
f21f6220 AV |
654 | if (unnamed_dev_start > dev) |
655 | unnamed_dev_start = dev; | |
1da177e4 LT |
656 | spin_unlock(&unnamed_dev_lock); |
657 | return -EMFILE; | |
658 | } | |
659 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
5129a469 | 660 | s->s_bdi = &noop_backing_dev_info; |
1da177e4 LT |
661 | return 0; |
662 | } | |
663 | ||
664 | EXPORT_SYMBOL(set_anon_super); | |
665 | ||
666 | void kill_anon_super(struct super_block *sb) | |
667 | { | |
668 | int slot = MINOR(sb->s_dev); | |
669 | ||
670 | generic_shutdown_super(sb); | |
671 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 672 | ida_remove(&unnamed_dev_ida, slot); |
c63e09ec AV |
673 | if (slot < unnamed_dev_start) |
674 | unnamed_dev_start = slot; | |
1da177e4 LT |
675 | spin_unlock(&unnamed_dev_lock); |
676 | } | |
677 | ||
678 | EXPORT_SYMBOL(kill_anon_super); | |
679 | ||
1da177e4 LT |
680 | void kill_litter_super(struct super_block *sb) |
681 | { | |
682 | if (sb->s_root) | |
683 | d_genocide(sb->s_root); | |
684 | kill_anon_super(sb); | |
685 | } | |
686 | ||
687 | EXPORT_SYMBOL(kill_litter_super); | |
688 | ||
909e6d94 SH |
689 | static int ns_test_super(struct super_block *sb, void *data) |
690 | { | |
691 | return sb->s_fs_info == data; | |
692 | } | |
693 | ||
694 | static int ns_set_super(struct super_block *sb, void *data) | |
695 | { | |
696 | sb->s_fs_info = data; | |
697 | return set_anon_super(sb, NULL); | |
698 | } | |
699 | ||
700 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
701 | int (*fill_super)(struct super_block *, void *, int), | |
702 | struct vfsmount *mnt) | |
703 | { | |
704 | struct super_block *sb; | |
705 | ||
706 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
707 | if (IS_ERR(sb)) | |
708 | return PTR_ERR(sb); | |
709 | ||
710 | if (!sb->s_root) { | |
711 | int err; | |
712 | sb->s_flags = flags; | |
713 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
714 | if (err) { | |
74dbbdd7 | 715 | deactivate_locked_super(sb); |
909e6d94 SH |
716 | return err; |
717 | } | |
718 | ||
719 | sb->s_flags |= MS_ACTIVE; | |
720 | } | |
721 | ||
722 | simple_set_mnt(mnt, sb); | |
723 | return 0; | |
724 | } | |
725 | ||
726 | EXPORT_SYMBOL(get_sb_ns); | |
727 | ||
9361401e | 728 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
729 | static int set_bdev_super(struct super_block *s, void *data) |
730 | { | |
731 | s->s_bdev = data; | |
732 | s->s_dev = s->s_bdev->bd_dev; | |
32a88aa1 JA |
733 | |
734 | /* | |
735 | * We set the bdi here to the queue backing, file systems can | |
736 | * overwrite this in ->fill_super() | |
737 | */ | |
738 | s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info; | |
1da177e4 LT |
739 | return 0; |
740 | } | |
741 | ||
742 | static int test_bdev_super(struct super_block *s, void *data) | |
743 | { | |
744 | return (void *)s->s_bdev == data; | |
745 | } | |
746 | ||
454e2398 | 747 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 748 | int flags, const char *dev_name, void *data, |
454e2398 DH |
749 | int (*fill_super)(struct super_block *, void *, int), |
750 | struct vfsmount *mnt) | |
1da177e4 LT |
751 | { |
752 | struct block_device *bdev; | |
753 | struct super_block *s; | |
30c40d2c | 754 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
755 | int error = 0; |
756 | ||
30c40d2c AV |
757 | if (!(flags & MS_RDONLY)) |
758 | mode |= FMODE_WRITE; | |
759 | ||
760 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 761 | if (IS_ERR(bdev)) |
454e2398 | 762 | return PTR_ERR(bdev); |
1da177e4 LT |
763 | |
764 | /* | |
765 | * once the super is inserted into the list by sget, s_umount | |
766 | * will protect the lockfs code from trying to start a snapshot | |
767 | * while we are mounting | |
768 | */ | |
4fadd7bb CH |
769 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
770 | if (bdev->bd_fsfreeze_count > 0) { | |
771 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
772 | error = -EBUSY; | |
773 | goto error_bdev; | |
774 | } | |
1da177e4 | 775 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
4fadd7bb | 776 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
1da177e4 | 777 | if (IS_ERR(s)) |
454e2398 | 778 | goto error_s; |
1da177e4 LT |
779 | |
780 | if (s->s_root) { | |
781 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 782 | deactivate_locked_super(s); |
454e2398 DH |
783 | error = -EBUSY; |
784 | goto error_bdev; | |
1da177e4 | 785 | } |
454e2398 | 786 | |
4f331f01 TH |
787 | /* |
788 | * s_umount nests inside bd_mutex during | |
789 | * __invalidate_device(). close_bdev_exclusive() | |
790 | * acquires bd_mutex and can't be called under | |
791 | * s_umount. Drop s_umount temporarily. This is safe | |
792 | * as we're holding an active reference. | |
793 | */ | |
794 | up_write(&s->s_umount); | |
30c40d2c | 795 | close_bdev_exclusive(bdev, mode); |
4f331f01 | 796 | down_write(&s->s_umount); |
1da177e4 LT |
797 | } else { |
798 | char b[BDEVNAME_SIZE]; | |
799 | ||
800 | s->s_flags = flags; | |
30c40d2c | 801 | s->s_mode = mode; |
1da177e4 | 802 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 803 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 804 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 805 | if (error) { |
74dbbdd7 | 806 | deactivate_locked_super(s); |
454e2398 | 807 | goto error; |
fa675765 | 808 | } |
454e2398 DH |
809 | |
810 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 811 | bdev->bd_super = s; |
1da177e4 LT |
812 | } |
813 | ||
a3ec947c SB |
814 | simple_set_mnt(mnt, s); |
815 | return 0; | |
1da177e4 | 816 | |
454e2398 DH |
817 | error_s: |
818 | error = PTR_ERR(s); | |
819 | error_bdev: | |
30c40d2c | 820 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
821 | error: |
822 | return error; | |
1da177e4 LT |
823 | } |
824 | ||
825 | EXPORT_SYMBOL(get_sb_bdev); | |
826 | ||
827 | void kill_block_super(struct super_block *sb) | |
828 | { | |
829 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 830 | fmode_t mode = sb->s_mode; |
1da177e4 | 831 | |
ddbaaf30 | 832 | bdev->bd_super = NULL; |
1da177e4 LT |
833 | generic_shutdown_super(sb); |
834 | sync_blockdev(bdev); | |
30c40d2c | 835 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
836 | } |
837 | ||
838 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 839 | #endif |
1da177e4 | 840 | |
454e2398 | 841 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 842 | int flags, void *data, |
454e2398 DH |
843 | int (*fill_super)(struct super_block *, void *, int), |
844 | struct vfsmount *mnt) | |
1da177e4 LT |
845 | { |
846 | int error; | |
847 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
848 | ||
849 | if (IS_ERR(s)) | |
454e2398 | 850 | return PTR_ERR(s); |
1da177e4 LT |
851 | |
852 | s->s_flags = flags; | |
853 | ||
9b04c997 | 854 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 855 | if (error) { |
74dbbdd7 | 856 | deactivate_locked_super(s); |
454e2398 | 857 | return error; |
1da177e4 LT |
858 | } |
859 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
860 | simple_set_mnt(mnt, s); |
861 | return 0; | |
1da177e4 LT |
862 | } |
863 | ||
864 | EXPORT_SYMBOL(get_sb_nodev); | |
865 | ||
866 | static int compare_single(struct super_block *s, void *p) | |
867 | { | |
868 | return 1; | |
869 | } | |
870 | ||
454e2398 | 871 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 872 | int flags, void *data, |
454e2398 DH |
873 | int (*fill_super)(struct super_block *, void *, int), |
874 | struct vfsmount *mnt) | |
1da177e4 LT |
875 | { |
876 | struct super_block *s; | |
877 | int error; | |
878 | ||
879 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
880 | if (IS_ERR(s)) | |
454e2398 | 881 | return PTR_ERR(s); |
1da177e4 LT |
882 | if (!s->s_root) { |
883 | s->s_flags = flags; | |
9b04c997 | 884 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 885 | if (error) { |
74dbbdd7 | 886 | deactivate_locked_super(s); |
454e2398 | 887 | return error; |
1da177e4 LT |
888 | } |
889 | s->s_flags |= MS_ACTIVE; | |
9329d1be KS |
890 | } else { |
891 | do_remount_sb(s, flags, data, 0); | |
1da177e4 | 892 | } |
a3ec947c SB |
893 | simple_set_mnt(mnt, s); |
894 | return 0; | |
1da177e4 LT |
895 | } |
896 | ||
897 | EXPORT_SYMBOL(get_sb_single); | |
898 | ||
899 | struct vfsmount * | |
bb4a58bf | 900 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 901 | { |
1da177e4 | 902 | struct vfsmount *mnt; |
1da177e4 | 903 | char *secdata = NULL; |
454e2398 | 904 | int error; |
1da177e4 LT |
905 | |
906 | if (!type) | |
907 | return ERR_PTR(-ENODEV); | |
1da177e4 | 908 | |
454e2398 | 909 | error = -ENOMEM; |
1da177e4 LT |
910 | mnt = alloc_vfsmnt(name); |
911 | if (!mnt) | |
912 | goto out; | |
913 | ||
8089352a AV |
914 | if (flags & MS_KERNMOUNT) |
915 | mnt->mnt_flags = MNT_INTERNAL; | |
916 | ||
e0007529 | 917 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 918 | secdata = alloc_secdata(); |
454e2398 | 919 | if (!secdata) |
1da177e4 | 920 | goto out_mnt; |
1da177e4 | 921 | |
e0007529 | 922 | error = security_sb_copy_data(data, secdata); |
454e2398 | 923 | if (error) |
1da177e4 | 924 | goto out_free_secdata; |
1da177e4 LT |
925 | } |
926 | ||
454e2398 DH |
927 | error = type->get_sb(type, flags, name, data, mnt); |
928 | if (error < 0) | |
1da177e4 | 929 | goto out_free_secdata; |
b4c07bce | 930 | BUG_ON(!mnt->mnt_sb); |
5129a469 | 931 | WARN_ON(!mnt->mnt_sb->s_bdi); |
7a4dec53 | 932 | mnt->mnt_sb->s_flags |= MS_BORN; |
454e2398 | 933 | |
5129a469 JE |
934 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
935 | if (error) | |
936 | goto out_sb; | |
454e2398 | 937 | |
42cb56ae JL |
938 | /* |
939 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE | |
940 | * but s_maxbytes was an unsigned long long for many releases. Throw | |
941 | * this warning for a little while to try and catch filesystems that | |
942 | * violate this rule. This warning should be either removed or | |
943 | * converted to a BUG() in 2.6.34. | |
944 | */ | |
945 | WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " | |
946 | "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes); | |
947 | ||
454e2398 | 948 | mnt->mnt_mountpoint = mnt->mnt_root; |
1da177e4 | 949 | mnt->mnt_parent = mnt; |
454e2398 | 950 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 951 | free_secdata(secdata); |
1da177e4 LT |
952 | return mnt; |
953 | out_sb: | |
454e2398 | 954 | dput(mnt->mnt_root); |
74dbbdd7 | 955 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
956 | out_free_secdata: |
957 | free_secdata(secdata); | |
958 | out_mnt: | |
959 | free_vfsmnt(mnt); | |
960 | out: | |
454e2398 | 961 | return ERR_PTR(error); |
1da177e4 LT |
962 | } |
963 | ||
bb4a58bf TM |
964 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
965 | ||
18e9e510 | 966 | /** |
7000d3c4 RD |
967 | * freeze_super - lock the filesystem and force it into a consistent state |
968 | * @sb: the super to lock | |
18e9e510 JB |
969 | * |
970 | * Syncs the super to make sure the filesystem is consistent and calls the fs's | |
971 | * freeze_fs. Subsequent calls to this without first thawing the fs will return | |
972 | * -EBUSY. | |
973 | */ | |
974 | int freeze_super(struct super_block *sb) | |
975 | { | |
976 | int ret; | |
977 | ||
978 | atomic_inc(&sb->s_active); | |
979 | down_write(&sb->s_umount); | |
980 | if (sb->s_frozen) { | |
981 | deactivate_locked_super(sb); | |
982 | return -EBUSY; | |
983 | } | |
984 | ||
985 | if (sb->s_flags & MS_RDONLY) { | |
986 | sb->s_frozen = SB_FREEZE_TRANS; | |
987 | smp_wmb(); | |
988 | up_write(&sb->s_umount); | |
989 | return 0; | |
990 | } | |
991 | ||
992 | sb->s_frozen = SB_FREEZE_WRITE; | |
993 | smp_wmb(); | |
994 | ||
995 | sync_filesystem(sb); | |
996 | ||
997 | sb->s_frozen = SB_FREEZE_TRANS; | |
998 | smp_wmb(); | |
999 | ||
1000 | sync_blockdev(sb->s_bdev); | |
1001 | if (sb->s_op->freeze_fs) { | |
1002 | ret = sb->s_op->freeze_fs(sb); | |
1003 | if (ret) { | |
1004 | printk(KERN_ERR | |
1005 | "VFS:Filesystem freeze failed\n"); | |
1006 | sb->s_frozen = SB_UNFROZEN; | |
1007 | deactivate_locked_super(sb); | |
1008 | return ret; | |
1009 | } | |
1010 | } | |
1011 | up_write(&sb->s_umount); | |
1012 | return 0; | |
1013 | } | |
1014 | EXPORT_SYMBOL(freeze_super); | |
1015 | ||
1016 | /** | |
1017 | * thaw_super -- unlock filesystem | |
1018 | * @sb: the super to thaw | |
1019 | * | |
1020 | * Unlocks the filesystem and marks it writeable again after freeze_super(). | |
1021 | */ | |
1022 | int thaw_super(struct super_block *sb) | |
1023 | { | |
1024 | int error; | |
1025 | ||
1026 | down_write(&sb->s_umount); | |
1027 | if (sb->s_frozen == SB_UNFROZEN) { | |
1028 | up_write(&sb->s_umount); | |
1029 | return -EINVAL; | |
1030 | } | |
1031 | ||
1032 | if (sb->s_flags & MS_RDONLY) | |
1033 | goto out; | |
1034 | ||
1035 | if (sb->s_op->unfreeze_fs) { | |
1036 | error = sb->s_op->unfreeze_fs(sb); | |
1037 | if (error) { | |
1038 | printk(KERN_ERR | |
1039 | "VFS:Filesystem thaw failed\n"); | |
1040 | sb->s_frozen = SB_FREEZE_TRANS; | |
1041 | up_write(&sb->s_umount); | |
1042 | return error; | |
1043 | } | |
1044 | } | |
1045 | ||
1046 | out: | |
1047 | sb->s_frozen = SB_UNFROZEN; | |
1048 | smp_wmb(); | |
1049 | wake_up(&sb->s_wait_unfrozen); | |
1050 | deactivate_locked_super(sb); | |
1051 | ||
1052 | return 0; | |
1053 | } | |
1054 | EXPORT_SYMBOL(thaw_super); | |
1055 | ||
79c0b2df MS |
1056 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
1057 | { | |
1058 | int err; | |
1059 | const char *subtype = strchr(fstype, '.'); | |
1060 | if (subtype) { | |
1061 | subtype++; | |
1062 | err = -EINVAL; | |
1063 | if (!subtype[0]) | |
1064 | goto err; | |
1065 | } else | |
1066 | subtype = ""; | |
1067 | ||
1068 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
1069 | err = -ENOMEM; | |
1070 | if (!mnt->mnt_sb->s_subtype) | |
1071 | goto err; | |
1072 | return mnt; | |
1073 | ||
1074 | err: | |
1075 | mntput(mnt); | |
1076 | return ERR_PTR(err); | |
1077 | } | |
1078 | ||
bb4a58bf TM |
1079 | struct vfsmount * |
1080 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
1081 | { | |
1082 | struct file_system_type *type = get_fs_type(fstype); | |
1083 | struct vfsmount *mnt; | |
1084 | if (!type) | |
1085 | return ERR_PTR(-ENODEV); | |
1086 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
1087 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
1088 | !mnt->mnt_sb->s_subtype) | |
1089 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
1090 | put_filesystem(type); |
1091 | return mnt; | |
1092 | } | |
8a4e98d9 | 1093 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 1094 | |
8bf9725c | 1095 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 1096 | { |
8bf9725c | 1097 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
1098 | } |
1099 | ||
8bf9725c | 1100 | EXPORT_SYMBOL_GPL(kern_mount_data); |