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> | |
25 | #include <linux/init.h> | |
26 | #include <linux/smp_lock.h> | |
27 | #include <linux/acct.h> | |
28 | #include <linux/blkdev.h> | |
29 | #include <linux/quotaops.h> | |
30 | #include <linux/namei.h> | |
1da177e4 LT |
31 | #include <linux/mount.h> |
32 | #include <linux/security.h> | |
33 | #include <linux/syscalls.h> | |
34 | #include <linux/vfs.h> | |
35 | #include <linux/writeback.h> /* for the emergency remount stuff */ | |
36 | #include <linux/idr.h> | |
37 | #include <linux/kobject.h> | |
353ab6e9 | 38 | #include <linux/mutex.h> |
49e0d02c | 39 | #include <linux/file.h> |
1da177e4 | 40 | #include <asm/uaccess.h> |
6d59e7f5 | 41 | #include "internal.h" |
1da177e4 LT |
42 | |
43 | ||
1da177e4 LT |
44 | LIST_HEAD(super_blocks); |
45 | DEFINE_SPINLOCK(sb_lock); | |
46 | ||
47 | /** | |
48 | * alloc_super - create new superblock | |
fe2bbc48 | 49 | * @type: filesystem type superblock should belong to |
1da177e4 LT |
50 | * |
51 | * Allocates and initializes a new &struct super_block. alloc_super() | |
52 | * returns a pointer new superblock or %NULL if allocation had failed. | |
53 | */ | |
cf516249 | 54 | static struct super_block *alloc_super(struct file_system_type *type) |
1da177e4 | 55 | { |
11b0b5ab | 56 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
1da177e4 LT |
57 | static struct super_operations default_op; |
58 | ||
59 | if (s) { | |
1da177e4 LT |
60 | if (security_sb_alloc(s)) { |
61 | kfree(s); | |
62 | s = NULL; | |
63 | goto out; | |
64 | } | |
65 | INIT_LIST_HEAD(&s->s_dirty); | |
66 | INIT_LIST_HEAD(&s->s_io); | |
0e0f4fc2 | 67 | INIT_LIST_HEAD(&s->s_more_io); |
1da177e4 LT |
68 | INIT_LIST_HEAD(&s->s_files); |
69 | INIT_LIST_HEAD(&s->s_instances); | |
70 | INIT_HLIST_HEAD(&s->s_anon); | |
71 | INIT_LIST_HEAD(&s->s_inodes); | |
da3bbdd4 | 72 | INIT_LIST_HEAD(&s->s_dentry_lru); |
1da177e4 | 73 | init_rwsem(&s->s_umount); |
7892f2f4 | 74 | mutex_init(&s->s_lock); |
897c6ff9 | 75 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
cf516249 IM |
76 | /* |
77 | * The locking rules for s_lock are up to the | |
78 | * filesystem. For example ext3fs has different | |
79 | * lock ordering than usbfs: | |
80 | */ | |
81 | lockdep_set_class(&s->s_lock, &type->s_lock_key); | |
ada723dc PZ |
82 | /* |
83 | * sget() can have s_umount recursion. | |
84 | * | |
85 | * When it cannot find a suitable sb, it allocates a new | |
86 | * one (this one), and tries again to find a suitable old | |
87 | * one. | |
88 | * | |
89 | * In case that succeeds, it will acquire the s_umount | |
90 | * lock of the old one. Since these are clearly distrinct | |
91 | * locks, and this object isn't exposed yet, there's no | |
92 | * risk of deadlocks. | |
93 | * | |
94 | * Annotate this by putting this lock in a different | |
95 | * subclass. | |
96 | */ | |
97 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); | |
1da177e4 LT |
98 | s->s_count = S_BIAS; |
99 | atomic_set(&s->s_active, 1); | |
a11f3a05 | 100 | mutex_init(&s->s_vfs_rename_mutex); |
d3be915f IM |
101 | mutex_init(&s->s_dquot.dqio_mutex); |
102 | mutex_init(&s->s_dquot.dqonoff_mutex); | |
1da177e4 LT |
103 | init_rwsem(&s->s_dquot.dqptr_sem); |
104 | init_waitqueue_head(&s->s_wait_unfrozen); | |
105 | s->s_maxbytes = MAX_NON_LFS; | |
106 | s->dq_op = sb_dquot_ops; | |
107 | s->s_qcop = sb_quotactl_ops; | |
108 | s->s_op = &default_op; | |
109 | s->s_time_gran = 1000000000; | |
110 | } | |
111 | out: | |
112 | return s; | |
113 | } | |
114 | ||
115 | /** | |
116 | * destroy_super - frees a superblock | |
117 | * @s: superblock to free | |
118 | * | |
119 | * Frees a superblock. | |
120 | */ | |
121 | static inline void destroy_super(struct super_block *s) | |
122 | { | |
123 | security_sb_free(s); | |
79c0b2df | 124 | kfree(s->s_subtype); |
b3b304a2 | 125 | kfree(s->s_options); |
1da177e4 LT |
126 | kfree(s); |
127 | } | |
128 | ||
129 | /* Superblock refcounting */ | |
130 | ||
131 | /* | |
132 | * Drop a superblock's refcount. Returns non-zero if the superblock was | |
133 | * destroyed. The caller must hold sb_lock. | |
134 | */ | |
6b09ae66 | 135 | static int __put_super(struct super_block *sb) |
1da177e4 LT |
136 | { |
137 | int ret = 0; | |
138 | ||
139 | if (!--sb->s_count) { | |
140 | destroy_super(sb); | |
141 | ret = 1; | |
142 | } | |
143 | return ret; | |
144 | } | |
145 | ||
146 | /* | |
147 | * Drop a superblock's refcount. | |
148 | * Returns non-zero if the superblock is about to be destroyed and | |
149 | * at least is already removed from super_blocks list, so if we are | |
150 | * making a loop through super blocks then we need to restart. | |
151 | * The caller must hold sb_lock. | |
152 | */ | |
153 | int __put_super_and_need_restart(struct super_block *sb) | |
154 | { | |
155 | /* check for race with generic_shutdown_super() */ | |
156 | if (list_empty(&sb->s_list)) { | |
157 | /* super block is removed, need to restart... */ | |
158 | __put_super(sb); | |
159 | return 1; | |
160 | } | |
161 | /* can't be the last, since s_list is still in use */ | |
162 | sb->s_count--; | |
163 | BUG_ON(sb->s_count == 0); | |
164 | return 0; | |
165 | } | |
166 | ||
167 | /** | |
168 | * put_super - drop a temporary reference to superblock | |
169 | * @sb: superblock in question | |
170 | * | |
171 | * Drops a temporary reference, frees superblock if there's no | |
172 | * references left. | |
173 | */ | |
174 | static void put_super(struct super_block *sb) | |
175 | { | |
176 | spin_lock(&sb_lock); | |
177 | __put_super(sb); | |
178 | spin_unlock(&sb_lock); | |
179 | } | |
180 | ||
181 | ||
182 | /** | |
183 | * deactivate_super - drop an active reference to superblock | |
184 | * @s: superblock to deactivate | |
185 | * | |
186 | * Drops an active reference to superblock, acquiring a temprory one if | |
187 | * there is no active references left. In that case we lock superblock, | |
188 | * tell fs driver to shut it down and drop the temporary reference we | |
189 | * had just acquired. | |
190 | */ | |
191 | void deactivate_super(struct super_block *s) | |
192 | { | |
193 | struct file_system_type *fs = s->s_type; | |
194 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { | |
195 | s->s_count -= S_BIAS-1; | |
196 | spin_unlock(&sb_lock); | |
9e3509e2 | 197 | vfs_dq_off(s, 0); |
1da177e4 LT |
198 | down_write(&s->s_umount); |
199 | fs->kill_sb(s); | |
200 | put_filesystem(fs); | |
201 | put_super(s); | |
202 | } | |
203 | } | |
204 | ||
205 | EXPORT_SYMBOL(deactivate_super); | |
206 | ||
74dbbdd7 AV |
207 | /** |
208 | * deactivate_locked_super - drop an active reference to superblock | |
209 | * @s: superblock to deactivate | |
210 | * | |
211 | * Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that | |
212 | * it does not unlock it until it's all over. As the result, it's safe to | |
213 | * use to dispose of new superblock on ->get_sb() failure exits - nobody | |
214 | * will see the sucker until it's all over. Equivalent using up_write + | |
215 | * deactivate_super is safe for that purpose only if superblock is either | |
216 | * safe to use or has NULL ->s_root when we unlock. | |
217 | */ | |
218 | void deactivate_locked_super(struct super_block *s) | |
219 | { | |
220 | struct file_system_type *fs = s->s_type; | |
221 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { | |
222 | s->s_count -= S_BIAS-1; | |
223 | spin_unlock(&sb_lock); | |
224 | vfs_dq_off(s, 0); | |
225 | fs->kill_sb(s); | |
226 | put_filesystem(fs); | |
227 | put_super(s); | |
228 | } else { | |
229 | up_write(&s->s_umount); | |
230 | } | |
231 | } | |
232 | ||
233 | EXPORT_SYMBOL(deactivate_locked_super); | |
234 | ||
1da177e4 LT |
235 | /** |
236 | * grab_super - acquire an active reference | |
237 | * @s: reference we are trying to make active | |
238 | * | |
239 | * Tries to acquire an active reference. grab_super() is used when we | |
240 | * had just found a superblock in super_blocks or fs_type->fs_supers | |
241 | * and want to turn it into a full-blown active reference. grab_super() | |
242 | * is called with sb_lock held and drops it. Returns 1 in case of | |
243 | * success, 0 if we had failed (superblock contents was already dead or | |
244 | * dying when grab_super() had been called). | |
245 | */ | |
9c4dbee7 | 246 | static int grab_super(struct super_block *s) __releases(sb_lock) |
1da177e4 LT |
247 | { |
248 | s->s_count++; | |
249 | spin_unlock(&sb_lock); | |
250 | down_write(&s->s_umount); | |
251 | if (s->s_root) { | |
252 | spin_lock(&sb_lock); | |
253 | if (s->s_count > S_BIAS) { | |
254 | atomic_inc(&s->s_active); | |
255 | s->s_count--; | |
256 | spin_unlock(&sb_lock); | |
257 | return 1; | |
258 | } | |
259 | spin_unlock(&sb_lock); | |
260 | } | |
261 | up_write(&s->s_umount); | |
262 | put_super(s); | |
263 | yield(); | |
264 | return 0; | |
265 | } | |
266 | ||
914e2637 AV |
267 | /* |
268 | * Superblock locking. We really ought to get rid of these two. | |
269 | */ | |
270 | void lock_super(struct super_block * sb) | |
271 | { | |
272 | get_fs_excl(); | |
273 | mutex_lock(&sb->s_lock); | |
274 | } | |
275 | ||
276 | void unlock_super(struct super_block * sb) | |
277 | { | |
278 | put_fs_excl(); | |
279 | mutex_unlock(&sb->s_lock); | |
280 | } | |
281 | ||
282 | EXPORT_SYMBOL(lock_super); | |
283 | EXPORT_SYMBOL(unlock_super); | |
284 | ||
1da177e4 LT |
285 | /** |
286 | * generic_shutdown_super - common helper for ->kill_sb() | |
287 | * @sb: superblock to kill | |
288 | * | |
289 | * generic_shutdown_super() does all fs-independent work on superblock | |
290 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects | |
291 | * that need destruction out of superblock, call generic_shutdown_super() | |
292 | * and release aforementioned objects. Note: dentries and inodes _are_ | |
293 | * taken care of and do not need specific handling. | |
c636ebdb DH |
294 | * |
295 | * Upon calling this function, the filesystem may no longer alter or | |
296 | * rearrange the set of dentries belonging to this super_block, nor may it | |
297 | * change the attachments of dentries to inodes. | |
1da177e4 LT |
298 | */ |
299 | void generic_shutdown_super(struct super_block *sb) | |
300 | { | |
ee9b6d61 | 301 | const struct super_operations *sop = sb->s_op; |
1da177e4 | 302 | |
efaee192 | 303 | |
c636ebdb DH |
304 | if (sb->s_root) { |
305 | shrink_dcache_for_umount(sb); | |
60b0680f | 306 | sync_filesystem(sb); |
a9e220f8 | 307 | get_fs_excl(); |
1da177e4 | 308 | sb->s_flags &= ~MS_ACTIVE; |
efaee192 | 309 | |
1da177e4 LT |
310 | /* bad name - it should be evict_inodes() */ |
311 | invalidate_inodes(sb); | |
1da177e4 | 312 | |
1da177e4 LT |
313 | if (sop->put_super) |
314 | sop->put_super(sb); | |
315 | ||
316 | /* Forget any remaining inodes */ | |
317 | if (invalidate_inodes(sb)) { | |
7b4fe29e DJ |
318 | printk("VFS: Busy inodes after unmount of %s. " |
319 | "Self-destruct in 5 seconds. Have a nice day...\n", | |
320 | sb->s_id); | |
1da177e4 | 321 | } |
a9e220f8 | 322 | put_fs_excl(); |
1da177e4 LT |
323 | } |
324 | spin_lock(&sb_lock); | |
325 | /* should be initialized for __put_super_and_need_restart() */ | |
326 | list_del_init(&sb->s_list); | |
327 | list_del(&sb->s_instances); | |
328 | spin_unlock(&sb_lock); | |
329 | up_write(&sb->s_umount); | |
330 | } | |
331 | ||
332 | EXPORT_SYMBOL(generic_shutdown_super); | |
333 | ||
334 | /** | |
335 | * sget - find or create a superblock | |
336 | * @type: filesystem type superblock should belong to | |
337 | * @test: comparison callback | |
338 | * @set: setup callback | |
339 | * @data: argument to each of them | |
340 | */ | |
341 | struct super_block *sget(struct file_system_type *type, | |
342 | int (*test)(struct super_block *,void *), | |
343 | int (*set)(struct super_block *,void *), | |
344 | void *data) | |
345 | { | |
346 | struct super_block *s = NULL; | |
d4730127 | 347 | struct super_block *old; |
1da177e4 LT |
348 | int err; |
349 | ||
350 | retry: | |
351 | spin_lock(&sb_lock); | |
d4730127 MK |
352 | if (test) { |
353 | list_for_each_entry(old, &type->fs_supers, s_instances) { | |
354 | if (!test(old, data)) | |
355 | continue; | |
356 | if (!grab_super(old)) | |
357 | goto retry; | |
a3cfbb53 LZ |
358 | if (s) { |
359 | up_write(&s->s_umount); | |
d4730127 | 360 | destroy_super(s); |
a3cfbb53 | 361 | } |
d4730127 MK |
362 | return old; |
363 | } | |
1da177e4 LT |
364 | } |
365 | if (!s) { | |
366 | spin_unlock(&sb_lock); | |
cf516249 | 367 | s = alloc_super(type); |
1da177e4 LT |
368 | if (!s) |
369 | return ERR_PTR(-ENOMEM); | |
370 | goto retry; | |
371 | } | |
372 | ||
373 | err = set(s, data); | |
374 | if (err) { | |
375 | spin_unlock(&sb_lock); | |
a3cfbb53 | 376 | up_write(&s->s_umount); |
1da177e4 LT |
377 | destroy_super(s); |
378 | return ERR_PTR(err); | |
379 | } | |
380 | s->s_type = type; | |
381 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
382 | list_add_tail(&s->s_list, &super_blocks); | |
383 | list_add(&s->s_instances, &type->fs_supers); | |
384 | spin_unlock(&sb_lock); | |
385 | get_filesystem(type); | |
386 | return s; | |
387 | } | |
388 | ||
389 | EXPORT_SYMBOL(sget); | |
390 | ||
391 | void drop_super(struct super_block *sb) | |
392 | { | |
393 | up_read(&sb->s_umount); | |
394 | put_super(sb); | |
395 | } | |
396 | ||
397 | EXPORT_SYMBOL(drop_super); | |
398 | ||
e5004753 CH |
399 | /** |
400 | * sync_supers - helper for periodic superblock writeback | |
401 | * | |
402 | * Call the write_super method if present on all dirty superblocks in | |
403 | * the system. This is for the periodic writeback used by most older | |
404 | * filesystems. For data integrity superblock writeback use | |
405 | * sync_filesystems() instead. | |
406 | * | |
1da177e4 LT |
407 | * Note: check the dirty flag before waiting, so we don't |
408 | * hold up the sync while mounting a device. (The newly | |
409 | * mounted device won't need syncing.) | |
410 | */ | |
411 | void sync_supers(void) | |
412 | { | |
618f0636 KK |
413 | struct super_block *sb; |
414 | ||
1da177e4 | 415 | spin_lock(&sb_lock); |
618f0636 KK |
416 | restart: |
417 | list_for_each_entry(sb, &super_blocks, s_list) { | |
e5004753 | 418 | if (sb->s_op->write_super && sb->s_dirt) { |
1da177e4 LT |
419 | sb->s_count++; |
420 | spin_unlock(&sb_lock); | |
e5004753 | 421 | |
1da177e4 | 422 | down_read(&sb->s_umount); |
e5004753 CH |
423 | if (sb->s_root && sb->s_dirt) |
424 | sb->s_op->write_super(sb); | |
618f0636 | 425 | up_read(&sb->s_umount); |
e5004753 | 426 | |
618f0636 KK |
427 | spin_lock(&sb_lock); |
428 | if (__put_super_and_need_restart(sb)) | |
429 | goto restart; | |
430 | } | |
431 | } | |
1da177e4 LT |
432 | spin_unlock(&sb_lock); |
433 | } | |
434 | ||
1da177e4 LT |
435 | /** |
436 | * get_super - get the superblock of a device | |
437 | * @bdev: device to get the superblock for | |
438 | * | |
439 | * Scans the superblock list and finds the superblock of the file system | |
440 | * mounted on the device given. %NULL is returned if no match is found. | |
441 | */ | |
442 | ||
443 | struct super_block * get_super(struct block_device *bdev) | |
444 | { | |
618f0636 KK |
445 | struct super_block *sb; |
446 | ||
1da177e4 LT |
447 | if (!bdev) |
448 | return NULL; | |
618f0636 | 449 | |
1da177e4 | 450 | spin_lock(&sb_lock); |
618f0636 KK |
451 | rescan: |
452 | list_for_each_entry(sb, &super_blocks, s_list) { | |
453 | if (sb->s_bdev == bdev) { | |
454 | sb->s_count++; | |
1da177e4 | 455 | spin_unlock(&sb_lock); |
618f0636 KK |
456 | down_read(&sb->s_umount); |
457 | if (sb->s_root) | |
458 | return sb; | |
459 | up_read(&sb->s_umount); | |
460 | /* restart only when sb is no longer on the list */ | |
461 | spin_lock(&sb_lock); | |
462 | if (__put_super_and_need_restart(sb)) | |
463 | goto rescan; | |
1da177e4 LT |
464 | } |
465 | } | |
466 | spin_unlock(&sb_lock); | |
467 | return NULL; | |
468 | } | |
469 | ||
470 | EXPORT_SYMBOL(get_super); | |
471 | ||
472 | struct super_block * user_get_super(dev_t dev) | |
473 | { | |
618f0636 | 474 | struct super_block *sb; |
1da177e4 | 475 | |
1da177e4 | 476 | spin_lock(&sb_lock); |
618f0636 KK |
477 | rescan: |
478 | list_for_each_entry(sb, &super_blocks, s_list) { | |
479 | if (sb->s_dev == dev) { | |
480 | sb->s_count++; | |
1da177e4 | 481 | spin_unlock(&sb_lock); |
618f0636 KK |
482 | down_read(&sb->s_umount); |
483 | if (sb->s_root) | |
484 | return sb; | |
485 | up_read(&sb->s_umount); | |
486 | /* restart only when sb is no longer on the list */ | |
487 | spin_lock(&sb_lock); | |
488 | if (__put_super_and_need_restart(sb)) | |
489 | goto rescan; | |
1da177e4 LT |
490 | } |
491 | } | |
492 | spin_unlock(&sb_lock); | |
493 | return NULL; | |
494 | } | |
495 | ||
257ac264 | 496 | SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) |
1da177e4 LT |
497 | { |
498 | struct super_block *s; | |
499 | struct ustat tmp; | |
500 | struct kstatfs sbuf; | |
501 | int err = -EINVAL; | |
502 | ||
503 | s = user_get_super(new_decode_dev(dev)); | |
504 | if (s == NULL) | |
505 | goto out; | |
726c3342 | 506 | err = vfs_statfs(s->s_root, &sbuf); |
1da177e4 LT |
507 | drop_super(s); |
508 | if (err) | |
509 | goto out; | |
510 | ||
511 | memset(&tmp,0,sizeof(struct ustat)); | |
512 | tmp.f_tfree = sbuf.f_bfree; | |
513 | tmp.f_tinode = sbuf.f_ffree; | |
514 | ||
515 | err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; | |
516 | out: | |
517 | return err; | |
518 | } | |
519 | ||
1da177e4 LT |
520 | /** |
521 | * do_remount_sb - asks filesystem to change mount options. | |
522 | * @sb: superblock in question | |
523 | * @flags: numeric part of options | |
524 | * @data: the rest of options | |
525 | * @force: whether or not to force the change | |
526 | * | |
527 | * Alters the mount options of a mounted file system. | |
528 | */ | |
529 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
530 | { | |
531 | int retval; | |
0ff5af83 | 532 | int remount_rw; |
1da177e4 | 533 | |
9361401e | 534 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
535 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
536 | return -EACCES; | |
9361401e | 537 | #endif |
1da177e4 LT |
538 | if (flags & MS_RDONLY) |
539 | acct_auto_close(sb); | |
540 | shrink_dcache_sb(sb); | |
60b0680f | 541 | sync_filesystem(sb); |
1da177e4 LT |
542 | |
543 | /* If we are remounting RDONLY and current sb is read/write, | |
544 | make sure there are no rw files opened */ | |
545 | if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { | |
546 | if (force) | |
547 | mark_files_ro(sb); | |
4aa98cf7 AV |
548 | else if (!fs_may_remount_ro(sb)) { |
549 | unlock_kernel(); | |
1da177e4 | 550 | return -EBUSY; |
4aa98cf7 | 551 | } |
9e3509e2 | 552 | retval = vfs_dq_off(sb, 1); |
4aa98cf7 AV |
553 | if (retval < 0 && retval != -ENOSYS) { |
554 | unlock_kernel(); | |
0ff5af83 | 555 | return -EBUSY; |
4aa98cf7 | 556 | } |
1da177e4 | 557 | } |
0ff5af83 | 558 | remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); |
1da177e4 LT |
559 | |
560 | if (sb->s_op->remount_fs) { | |
1da177e4 | 561 | retval = sb->s_op->remount_fs(sb, &flags, data); |
4aa98cf7 AV |
562 | if (retval) { |
563 | unlock_kernel(); | |
1da177e4 | 564 | return retval; |
4aa98cf7 | 565 | } |
1da177e4 LT |
566 | } |
567 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
0ff5af83 | 568 | if (remount_rw) |
9e3509e2 | 569 | vfs_dq_quota_on_remount(sb); |
1da177e4 LT |
570 | return 0; |
571 | } | |
572 | ||
a2a9537a | 573 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 LT |
574 | { |
575 | struct super_block *sb; | |
576 | ||
577 | spin_lock(&sb_lock); | |
578 | list_for_each_entry(sb, &super_blocks, s_list) { | |
579 | sb->s_count++; | |
580 | spin_unlock(&sb_lock); | |
443b94ba | 581 | down_write(&sb->s_umount); |
1da177e4 LT |
582 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
583 | /* | |
584 | * ->remount_fs needs lock_kernel(). | |
585 | * | |
586 | * What lock protects sb->s_flags?? | |
587 | */ | |
1da177e4 | 588 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
1da177e4 | 589 | } |
443b94ba AV |
590 | up_write(&sb->s_umount); |
591 | put_super(sb); | |
1da177e4 LT |
592 | spin_lock(&sb_lock); |
593 | } | |
594 | spin_unlock(&sb_lock); | |
a2a9537a | 595 | kfree(work); |
1da177e4 LT |
596 | printk("Emergency Remount complete\n"); |
597 | } | |
598 | ||
599 | void emergency_remount(void) | |
600 | { | |
a2a9537a JA |
601 | struct work_struct *work; |
602 | ||
603 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
604 | if (work) { | |
605 | INIT_WORK(work, do_emergency_remount); | |
606 | schedule_work(work); | |
607 | } | |
1da177e4 LT |
608 | } |
609 | ||
610 | /* | |
611 | * Unnamed block devices are dummy devices used by virtual | |
612 | * filesystems which don't use real block-devices. -- jrs | |
613 | */ | |
614 | ||
ad76cbc6 | 615 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 LT |
616 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
617 | ||
618 | int set_anon_super(struct super_block *s, void *data) | |
619 | { | |
620 | int dev; | |
621 | int error; | |
622 | ||
623 | retry: | |
ad76cbc6 | 624 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
625 | return -ENOMEM; |
626 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 627 | error = ida_get_new(&unnamed_dev_ida, &dev); |
1da177e4 LT |
628 | spin_unlock(&unnamed_dev_lock); |
629 | if (error == -EAGAIN) | |
630 | /* We raced and lost with another CPU. */ | |
631 | goto retry; | |
632 | else if (error) | |
633 | return -EAGAIN; | |
634 | ||
635 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
636 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 637 | ida_remove(&unnamed_dev_ida, dev); |
1da177e4 LT |
638 | spin_unlock(&unnamed_dev_lock); |
639 | return -EMFILE; | |
640 | } | |
641 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
642 | return 0; | |
643 | } | |
644 | ||
645 | EXPORT_SYMBOL(set_anon_super); | |
646 | ||
647 | void kill_anon_super(struct super_block *sb) | |
648 | { | |
649 | int slot = MINOR(sb->s_dev); | |
650 | ||
651 | generic_shutdown_super(sb); | |
652 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 653 | ida_remove(&unnamed_dev_ida, slot); |
1da177e4 LT |
654 | spin_unlock(&unnamed_dev_lock); |
655 | } | |
656 | ||
657 | EXPORT_SYMBOL(kill_anon_super); | |
658 | ||
1da177e4 LT |
659 | void kill_litter_super(struct super_block *sb) |
660 | { | |
661 | if (sb->s_root) | |
662 | d_genocide(sb->s_root); | |
663 | kill_anon_super(sb); | |
664 | } | |
665 | ||
666 | EXPORT_SYMBOL(kill_litter_super); | |
667 | ||
909e6d94 SH |
668 | static int ns_test_super(struct super_block *sb, void *data) |
669 | { | |
670 | return sb->s_fs_info == data; | |
671 | } | |
672 | ||
673 | static int ns_set_super(struct super_block *sb, void *data) | |
674 | { | |
675 | sb->s_fs_info = data; | |
676 | return set_anon_super(sb, NULL); | |
677 | } | |
678 | ||
679 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
680 | int (*fill_super)(struct super_block *, void *, int), | |
681 | struct vfsmount *mnt) | |
682 | { | |
683 | struct super_block *sb; | |
684 | ||
685 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
686 | if (IS_ERR(sb)) | |
687 | return PTR_ERR(sb); | |
688 | ||
689 | if (!sb->s_root) { | |
690 | int err; | |
691 | sb->s_flags = flags; | |
692 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
693 | if (err) { | |
74dbbdd7 | 694 | deactivate_locked_super(sb); |
909e6d94 SH |
695 | return err; |
696 | } | |
697 | ||
698 | sb->s_flags |= MS_ACTIVE; | |
699 | } | |
700 | ||
701 | simple_set_mnt(mnt, sb); | |
702 | return 0; | |
703 | } | |
704 | ||
705 | EXPORT_SYMBOL(get_sb_ns); | |
706 | ||
9361401e | 707 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
708 | static int set_bdev_super(struct super_block *s, void *data) |
709 | { | |
710 | s->s_bdev = data; | |
711 | s->s_dev = s->s_bdev->bd_dev; | |
712 | return 0; | |
713 | } | |
714 | ||
715 | static int test_bdev_super(struct super_block *s, void *data) | |
716 | { | |
717 | return (void *)s->s_bdev == data; | |
718 | } | |
719 | ||
454e2398 | 720 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 721 | int flags, const char *dev_name, void *data, |
454e2398 DH |
722 | int (*fill_super)(struct super_block *, void *, int), |
723 | struct vfsmount *mnt) | |
1da177e4 LT |
724 | { |
725 | struct block_device *bdev; | |
726 | struct super_block *s; | |
30c40d2c | 727 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
728 | int error = 0; |
729 | ||
30c40d2c AV |
730 | if (!(flags & MS_RDONLY)) |
731 | mode |= FMODE_WRITE; | |
732 | ||
733 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 734 | if (IS_ERR(bdev)) |
454e2398 | 735 | return PTR_ERR(bdev); |
1da177e4 LT |
736 | |
737 | /* | |
738 | * once the super is inserted into the list by sget, s_umount | |
739 | * will protect the lockfs code from trying to start a snapshot | |
740 | * while we are mounting | |
741 | */ | |
f73ca1b7 | 742 | down(&bdev->bd_mount_sem); |
1da177e4 | 743 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
f73ca1b7 | 744 | up(&bdev->bd_mount_sem); |
1da177e4 | 745 | if (IS_ERR(s)) |
454e2398 | 746 | goto error_s; |
1da177e4 LT |
747 | |
748 | if (s->s_root) { | |
749 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 750 | deactivate_locked_super(s); |
454e2398 DH |
751 | error = -EBUSY; |
752 | goto error_bdev; | |
1da177e4 | 753 | } |
454e2398 | 754 | |
30c40d2c | 755 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
756 | } else { |
757 | char b[BDEVNAME_SIZE]; | |
758 | ||
759 | s->s_flags = flags; | |
30c40d2c | 760 | s->s_mode = mode; |
1da177e4 | 761 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 762 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 763 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 764 | if (error) { |
74dbbdd7 | 765 | deactivate_locked_super(s); |
454e2398 | 766 | goto error; |
fa675765 | 767 | } |
454e2398 DH |
768 | |
769 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 770 | bdev->bd_super = s; |
1da177e4 LT |
771 | } |
772 | ||
a3ec947c SB |
773 | simple_set_mnt(mnt, s); |
774 | return 0; | |
1da177e4 | 775 | |
454e2398 DH |
776 | error_s: |
777 | error = PTR_ERR(s); | |
778 | error_bdev: | |
30c40d2c | 779 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
780 | error: |
781 | return error; | |
1da177e4 LT |
782 | } |
783 | ||
784 | EXPORT_SYMBOL(get_sb_bdev); | |
785 | ||
786 | void kill_block_super(struct super_block *sb) | |
787 | { | |
788 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 789 | fmode_t mode = sb->s_mode; |
1da177e4 | 790 | |
ddbaaf30 | 791 | bdev->bd_super = NULL; |
1da177e4 LT |
792 | generic_shutdown_super(sb); |
793 | sync_blockdev(bdev); | |
30c40d2c | 794 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
795 | } |
796 | ||
797 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 798 | #endif |
1da177e4 | 799 | |
454e2398 | 800 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 801 | int flags, void *data, |
454e2398 DH |
802 | int (*fill_super)(struct super_block *, void *, int), |
803 | struct vfsmount *mnt) | |
1da177e4 LT |
804 | { |
805 | int error; | |
806 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
807 | ||
808 | if (IS_ERR(s)) | |
454e2398 | 809 | return PTR_ERR(s); |
1da177e4 LT |
810 | |
811 | s->s_flags = flags; | |
812 | ||
9b04c997 | 813 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 814 | if (error) { |
74dbbdd7 | 815 | deactivate_locked_super(s); |
454e2398 | 816 | return error; |
1da177e4 LT |
817 | } |
818 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
819 | simple_set_mnt(mnt, s); |
820 | return 0; | |
1da177e4 LT |
821 | } |
822 | ||
823 | EXPORT_SYMBOL(get_sb_nodev); | |
824 | ||
825 | static int compare_single(struct super_block *s, void *p) | |
826 | { | |
827 | return 1; | |
828 | } | |
829 | ||
454e2398 | 830 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 831 | int flags, void *data, |
454e2398 DH |
832 | int (*fill_super)(struct super_block *, void *, int), |
833 | struct vfsmount *mnt) | |
1da177e4 LT |
834 | { |
835 | struct super_block *s; | |
836 | int error; | |
837 | ||
838 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
839 | if (IS_ERR(s)) | |
454e2398 | 840 | return PTR_ERR(s); |
1da177e4 LT |
841 | if (!s->s_root) { |
842 | s->s_flags = flags; | |
9b04c997 | 843 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 844 | if (error) { |
74dbbdd7 | 845 | deactivate_locked_super(s); |
454e2398 | 846 | return error; |
1da177e4 LT |
847 | } |
848 | s->s_flags |= MS_ACTIVE; | |
849 | } | |
850 | do_remount_sb(s, flags, data, 0); | |
a3ec947c SB |
851 | simple_set_mnt(mnt, s); |
852 | return 0; | |
1da177e4 LT |
853 | } |
854 | ||
855 | EXPORT_SYMBOL(get_sb_single); | |
856 | ||
857 | struct vfsmount * | |
bb4a58bf | 858 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 859 | { |
1da177e4 | 860 | struct vfsmount *mnt; |
1da177e4 | 861 | char *secdata = NULL; |
454e2398 | 862 | int error; |
1da177e4 LT |
863 | |
864 | if (!type) | |
865 | return ERR_PTR(-ENODEV); | |
1da177e4 | 866 | |
454e2398 | 867 | error = -ENOMEM; |
1da177e4 LT |
868 | mnt = alloc_vfsmnt(name); |
869 | if (!mnt) | |
870 | goto out; | |
871 | ||
e0007529 | 872 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 873 | secdata = alloc_secdata(); |
454e2398 | 874 | if (!secdata) |
1da177e4 | 875 | goto out_mnt; |
1da177e4 | 876 | |
e0007529 | 877 | error = security_sb_copy_data(data, secdata); |
454e2398 | 878 | if (error) |
1da177e4 | 879 | goto out_free_secdata; |
1da177e4 LT |
880 | } |
881 | ||
454e2398 DH |
882 | error = type->get_sb(type, flags, name, data, mnt); |
883 | if (error < 0) | |
1da177e4 | 884 | goto out_free_secdata; |
b4c07bce | 885 | BUG_ON(!mnt->mnt_sb); |
454e2398 | 886 | |
12204e24 | 887 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
1da177e4 LT |
888 | if (error) |
889 | goto out_sb; | |
454e2398 DH |
890 | |
891 | mnt->mnt_mountpoint = mnt->mnt_root; | |
1da177e4 | 892 | mnt->mnt_parent = mnt; |
454e2398 | 893 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 894 | free_secdata(secdata); |
1da177e4 LT |
895 | return mnt; |
896 | out_sb: | |
454e2398 | 897 | dput(mnt->mnt_root); |
74dbbdd7 | 898 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
899 | out_free_secdata: |
900 | free_secdata(secdata); | |
901 | out_mnt: | |
902 | free_vfsmnt(mnt); | |
903 | out: | |
454e2398 | 904 | return ERR_PTR(error); |
1da177e4 LT |
905 | } |
906 | ||
bb4a58bf TM |
907 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
908 | ||
79c0b2df MS |
909 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
910 | { | |
911 | int err; | |
912 | const char *subtype = strchr(fstype, '.'); | |
913 | if (subtype) { | |
914 | subtype++; | |
915 | err = -EINVAL; | |
916 | if (!subtype[0]) | |
917 | goto err; | |
918 | } else | |
919 | subtype = ""; | |
920 | ||
921 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
922 | err = -ENOMEM; | |
923 | if (!mnt->mnt_sb->s_subtype) | |
924 | goto err; | |
925 | return mnt; | |
926 | ||
927 | err: | |
928 | mntput(mnt); | |
929 | return ERR_PTR(err); | |
930 | } | |
931 | ||
bb4a58bf TM |
932 | struct vfsmount * |
933 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
934 | { | |
935 | struct file_system_type *type = get_fs_type(fstype); | |
936 | struct vfsmount *mnt; | |
937 | if (!type) | |
938 | return ERR_PTR(-ENODEV); | |
939 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
940 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
941 | !mnt->mnt_sb->s_subtype) | |
942 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
943 | put_filesystem(type); |
944 | return mnt; | |
945 | } | |
8a4e98d9 | 946 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 947 | |
8bf9725c | 948 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 949 | { |
8bf9725c | 950 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
951 | } |
952 | ||
8bf9725c | 953 | EXPORT_SYMBOL_GPL(kern_mount_data); |