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 | lock_super(sb); |
424 | if (sb->s_root && sb->s_dirt) | |
425 | sb->s_op->write_super(sb); | |
426 | unlock_super(sb); | |
618f0636 | 427 | up_read(&sb->s_umount); |
e5004753 | 428 | |
618f0636 KK |
429 | spin_lock(&sb_lock); |
430 | if (__put_super_and_need_restart(sb)) | |
431 | goto restart; | |
432 | } | |
433 | } | |
1da177e4 LT |
434 | spin_unlock(&sb_lock); |
435 | } | |
436 | ||
1da177e4 LT |
437 | /** |
438 | * get_super - get the superblock of a device | |
439 | * @bdev: device to get the superblock for | |
440 | * | |
441 | * Scans the superblock list and finds the superblock of the file system | |
442 | * mounted on the device given. %NULL is returned if no match is found. | |
443 | */ | |
444 | ||
445 | struct super_block * get_super(struct block_device *bdev) | |
446 | { | |
618f0636 KK |
447 | struct super_block *sb; |
448 | ||
1da177e4 LT |
449 | if (!bdev) |
450 | return NULL; | |
618f0636 | 451 | |
1da177e4 | 452 | spin_lock(&sb_lock); |
618f0636 KK |
453 | rescan: |
454 | list_for_each_entry(sb, &super_blocks, s_list) { | |
455 | if (sb->s_bdev == bdev) { | |
456 | sb->s_count++; | |
1da177e4 | 457 | spin_unlock(&sb_lock); |
618f0636 KK |
458 | down_read(&sb->s_umount); |
459 | if (sb->s_root) | |
460 | return sb; | |
461 | up_read(&sb->s_umount); | |
462 | /* restart only when sb is no longer on the list */ | |
463 | spin_lock(&sb_lock); | |
464 | if (__put_super_and_need_restart(sb)) | |
465 | goto rescan; | |
1da177e4 LT |
466 | } |
467 | } | |
468 | spin_unlock(&sb_lock); | |
469 | return NULL; | |
470 | } | |
471 | ||
472 | EXPORT_SYMBOL(get_super); | |
473 | ||
474 | struct super_block * user_get_super(dev_t dev) | |
475 | { | |
618f0636 | 476 | struct super_block *sb; |
1da177e4 | 477 | |
1da177e4 | 478 | spin_lock(&sb_lock); |
618f0636 KK |
479 | rescan: |
480 | list_for_each_entry(sb, &super_blocks, s_list) { | |
481 | if (sb->s_dev == dev) { | |
482 | sb->s_count++; | |
1da177e4 | 483 | spin_unlock(&sb_lock); |
618f0636 KK |
484 | down_read(&sb->s_umount); |
485 | if (sb->s_root) | |
486 | return sb; | |
487 | up_read(&sb->s_umount); | |
488 | /* restart only when sb is no longer on the list */ | |
489 | spin_lock(&sb_lock); | |
490 | if (__put_super_and_need_restart(sb)) | |
491 | goto rescan; | |
1da177e4 LT |
492 | } |
493 | } | |
494 | spin_unlock(&sb_lock); | |
495 | return NULL; | |
496 | } | |
497 | ||
257ac264 | 498 | SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) |
1da177e4 LT |
499 | { |
500 | struct super_block *s; | |
501 | struct ustat tmp; | |
502 | struct kstatfs sbuf; | |
503 | int err = -EINVAL; | |
504 | ||
505 | s = user_get_super(new_decode_dev(dev)); | |
506 | if (s == NULL) | |
507 | goto out; | |
726c3342 | 508 | err = vfs_statfs(s->s_root, &sbuf); |
1da177e4 LT |
509 | drop_super(s); |
510 | if (err) | |
511 | goto out; | |
512 | ||
513 | memset(&tmp,0,sizeof(struct ustat)); | |
514 | tmp.f_tfree = sbuf.f_bfree; | |
515 | tmp.f_tinode = sbuf.f_ffree; | |
516 | ||
517 | err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; | |
518 | out: | |
519 | return err; | |
520 | } | |
521 | ||
1da177e4 LT |
522 | /** |
523 | * do_remount_sb - asks filesystem to change mount options. | |
524 | * @sb: superblock in question | |
525 | * @flags: numeric part of options | |
526 | * @data: the rest of options | |
527 | * @force: whether or not to force the change | |
528 | * | |
529 | * Alters the mount options of a mounted file system. | |
530 | */ | |
531 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
532 | { | |
533 | int retval; | |
0ff5af83 | 534 | int remount_rw; |
1da177e4 | 535 | |
9361401e | 536 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
537 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
538 | return -EACCES; | |
9361401e | 539 | #endif |
1da177e4 LT |
540 | if (flags & MS_RDONLY) |
541 | acct_auto_close(sb); | |
542 | shrink_dcache_sb(sb); | |
60b0680f | 543 | sync_filesystem(sb); |
1da177e4 | 544 | |
4aa98cf7 | 545 | lock_kernel(); |
1da177e4 LT |
546 | /* If we are remounting RDONLY and current sb is read/write, |
547 | make sure there are no rw files opened */ | |
548 | if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { | |
549 | if (force) | |
550 | mark_files_ro(sb); | |
4aa98cf7 AV |
551 | else if (!fs_may_remount_ro(sb)) { |
552 | unlock_kernel(); | |
1da177e4 | 553 | return -EBUSY; |
4aa98cf7 | 554 | } |
9e3509e2 | 555 | retval = vfs_dq_off(sb, 1); |
4aa98cf7 AV |
556 | if (retval < 0 && retval != -ENOSYS) { |
557 | unlock_kernel(); | |
0ff5af83 | 558 | return -EBUSY; |
4aa98cf7 | 559 | } |
1da177e4 | 560 | } |
0ff5af83 | 561 | remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); |
1da177e4 LT |
562 | |
563 | if (sb->s_op->remount_fs) { | |
1da177e4 | 564 | retval = sb->s_op->remount_fs(sb, &flags, data); |
4aa98cf7 AV |
565 | if (retval) { |
566 | unlock_kernel(); | |
1da177e4 | 567 | return retval; |
4aa98cf7 | 568 | } |
1da177e4 LT |
569 | } |
570 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
4aa98cf7 | 571 | unlock_kernel(); |
0ff5af83 | 572 | if (remount_rw) |
9e3509e2 | 573 | vfs_dq_quota_on_remount(sb); |
1da177e4 LT |
574 | return 0; |
575 | } | |
576 | ||
a2a9537a | 577 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 LT |
578 | { |
579 | struct super_block *sb; | |
580 | ||
581 | spin_lock(&sb_lock); | |
582 | list_for_each_entry(sb, &super_blocks, s_list) { | |
583 | sb->s_count++; | |
584 | spin_unlock(&sb_lock); | |
443b94ba | 585 | down_write(&sb->s_umount); |
1da177e4 LT |
586 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
587 | /* | |
588 | * ->remount_fs needs lock_kernel(). | |
589 | * | |
590 | * What lock protects sb->s_flags?? | |
591 | */ | |
1da177e4 | 592 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
1da177e4 | 593 | } |
443b94ba AV |
594 | up_write(&sb->s_umount); |
595 | put_super(sb); | |
1da177e4 LT |
596 | spin_lock(&sb_lock); |
597 | } | |
598 | spin_unlock(&sb_lock); | |
a2a9537a | 599 | kfree(work); |
1da177e4 LT |
600 | printk("Emergency Remount complete\n"); |
601 | } | |
602 | ||
603 | void emergency_remount(void) | |
604 | { | |
a2a9537a JA |
605 | struct work_struct *work; |
606 | ||
607 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
608 | if (work) { | |
609 | INIT_WORK(work, do_emergency_remount); | |
610 | schedule_work(work); | |
611 | } | |
1da177e4 LT |
612 | } |
613 | ||
614 | /* | |
615 | * Unnamed block devices are dummy devices used by virtual | |
616 | * filesystems which don't use real block-devices. -- jrs | |
617 | */ | |
618 | ||
ad76cbc6 | 619 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 LT |
620 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
621 | ||
622 | int set_anon_super(struct super_block *s, void *data) | |
623 | { | |
624 | int dev; | |
625 | int error; | |
626 | ||
627 | retry: | |
ad76cbc6 | 628 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
629 | return -ENOMEM; |
630 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 631 | error = ida_get_new(&unnamed_dev_ida, &dev); |
1da177e4 LT |
632 | spin_unlock(&unnamed_dev_lock); |
633 | if (error == -EAGAIN) | |
634 | /* We raced and lost with another CPU. */ | |
635 | goto retry; | |
636 | else if (error) | |
637 | return -EAGAIN; | |
638 | ||
639 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
640 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 641 | ida_remove(&unnamed_dev_ida, dev); |
1da177e4 LT |
642 | spin_unlock(&unnamed_dev_lock); |
643 | return -EMFILE; | |
644 | } | |
645 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
646 | return 0; | |
647 | } | |
648 | ||
649 | EXPORT_SYMBOL(set_anon_super); | |
650 | ||
651 | void kill_anon_super(struct super_block *sb) | |
652 | { | |
653 | int slot = MINOR(sb->s_dev); | |
654 | ||
655 | generic_shutdown_super(sb); | |
656 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 657 | ida_remove(&unnamed_dev_ida, slot); |
1da177e4 LT |
658 | spin_unlock(&unnamed_dev_lock); |
659 | } | |
660 | ||
661 | EXPORT_SYMBOL(kill_anon_super); | |
662 | ||
1da177e4 LT |
663 | void kill_litter_super(struct super_block *sb) |
664 | { | |
665 | if (sb->s_root) | |
666 | d_genocide(sb->s_root); | |
667 | kill_anon_super(sb); | |
668 | } | |
669 | ||
670 | EXPORT_SYMBOL(kill_litter_super); | |
671 | ||
909e6d94 SH |
672 | static int ns_test_super(struct super_block *sb, void *data) |
673 | { | |
674 | return sb->s_fs_info == data; | |
675 | } | |
676 | ||
677 | static int ns_set_super(struct super_block *sb, void *data) | |
678 | { | |
679 | sb->s_fs_info = data; | |
680 | return set_anon_super(sb, NULL); | |
681 | } | |
682 | ||
683 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
684 | int (*fill_super)(struct super_block *, void *, int), | |
685 | struct vfsmount *mnt) | |
686 | { | |
687 | struct super_block *sb; | |
688 | ||
689 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
690 | if (IS_ERR(sb)) | |
691 | return PTR_ERR(sb); | |
692 | ||
693 | if (!sb->s_root) { | |
694 | int err; | |
695 | sb->s_flags = flags; | |
696 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
697 | if (err) { | |
74dbbdd7 | 698 | deactivate_locked_super(sb); |
909e6d94 SH |
699 | return err; |
700 | } | |
701 | ||
702 | sb->s_flags |= MS_ACTIVE; | |
703 | } | |
704 | ||
705 | simple_set_mnt(mnt, sb); | |
706 | return 0; | |
707 | } | |
708 | ||
709 | EXPORT_SYMBOL(get_sb_ns); | |
710 | ||
9361401e | 711 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
712 | static int set_bdev_super(struct super_block *s, void *data) |
713 | { | |
714 | s->s_bdev = data; | |
715 | s->s_dev = s->s_bdev->bd_dev; | |
716 | return 0; | |
717 | } | |
718 | ||
719 | static int test_bdev_super(struct super_block *s, void *data) | |
720 | { | |
721 | return (void *)s->s_bdev == data; | |
722 | } | |
723 | ||
454e2398 | 724 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 725 | int flags, const char *dev_name, void *data, |
454e2398 DH |
726 | int (*fill_super)(struct super_block *, void *, int), |
727 | struct vfsmount *mnt) | |
1da177e4 LT |
728 | { |
729 | struct block_device *bdev; | |
730 | struct super_block *s; | |
30c40d2c | 731 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
732 | int error = 0; |
733 | ||
30c40d2c AV |
734 | if (!(flags & MS_RDONLY)) |
735 | mode |= FMODE_WRITE; | |
736 | ||
737 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 738 | if (IS_ERR(bdev)) |
454e2398 | 739 | return PTR_ERR(bdev); |
1da177e4 LT |
740 | |
741 | /* | |
742 | * once the super is inserted into the list by sget, s_umount | |
743 | * will protect the lockfs code from trying to start a snapshot | |
744 | * while we are mounting | |
745 | */ | |
f73ca1b7 | 746 | down(&bdev->bd_mount_sem); |
1da177e4 | 747 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
f73ca1b7 | 748 | up(&bdev->bd_mount_sem); |
1da177e4 | 749 | if (IS_ERR(s)) |
454e2398 | 750 | goto error_s; |
1da177e4 LT |
751 | |
752 | if (s->s_root) { | |
753 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 754 | deactivate_locked_super(s); |
454e2398 DH |
755 | error = -EBUSY; |
756 | goto error_bdev; | |
1da177e4 | 757 | } |
454e2398 | 758 | |
30c40d2c | 759 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
760 | } else { |
761 | char b[BDEVNAME_SIZE]; | |
762 | ||
763 | s->s_flags = flags; | |
30c40d2c | 764 | s->s_mode = mode; |
1da177e4 | 765 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 766 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 767 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 768 | if (error) { |
74dbbdd7 | 769 | deactivate_locked_super(s); |
454e2398 | 770 | goto error; |
fa675765 | 771 | } |
454e2398 DH |
772 | |
773 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 774 | bdev->bd_super = s; |
1da177e4 LT |
775 | } |
776 | ||
a3ec947c SB |
777 | simple_set_mnt(mnt, s); |
778 | return 0; | |
1da177e4 | 779 | |
454e2398 DH |
780 | error_s: |
781 | error = PTR_ERR(s); | |
782 | error_bdev: | |
30c40d2c | 783 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
784 | error: |
785 | return error; | |
1da177e4 LT |
786 | } |
787 | ||
788 | EXPORT_SYMBOL(get_sb_bdev); | |
789 | ||
790 | void kill_block_super(struct super_block *sb) | |
791 | { | |
792 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 793 | fmode_t mode = sb->s_mode; |
1da177e4 | 794 | |
ddbaaf30 | 795 | bdev->bd_super = NULL; |
1da177e4 LT |
796 | generic_shutdown_super(sb); |
797 | sync_blockdev(bdev); | |
30c40d2c | 798 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
799 | } |
800 | ||
801 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 802 | #endif |
1da177e4 | 803 | |
454e2398 | 804 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 805 | int flags, void *data, |
454e2398 DH |
806 | int (*fill_super)(struct super_block *, void *, int), |
807 | struct vfsmount *mnt) | |
1da177e4 LT |
808 | { |
809 | int error; | |
810 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
811 | ||
812 | if (IS_ERR(s)) | |
454e2398 | 813 | return PTR_ERR(s); |
1da177e4 LT |
814 | |
815 | s->s_flags = flags; | |
816 | ||
9b04c997 | 817 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 818 | if (error) { |
74dbbdd7 | 819 | deactivate_locked_super(s); |
454e2398 | 820 | return error; |
1da177e4 LT |
821 | } |
822 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
823 | simple_set_mnt(mnt, s); |
824 | return 0; | |
1da177e4 LT |
825 | } |
826 | ||
827 | EXPORT_SYMBOL(get_sb_nodev); | |
828 | ||
829 | static int compare_single(struct super_block *s, void *p) | |
830 | { | |
831 | return 1; | |
832 | } | |
833 | ||
454e2398 | 834 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 835 | int flags, void *data, |
454e2398 DH |
836 | int (*fill_super)(struct super_block *, void *, int), |
837 | struct vfsmount *mnt) | |
1da177e4 LT |
838 | { |
839 | struct super_block *s; | |
840 | int error; | |
841 | ||
842 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
843 | if (IS_ERR(s)) | |
454e2398 | 844 | return PTR_ERR(s); |
1da177e4 LT |
845 | if (!s->s_root) { |
846 | s->s_flags = flags; | |
9b04c997 | 847 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 848 | if (error) { |
74dbbdd7 | 849 | deactivate_locked_super(s); |
454e2398 | 850 | return error; |
1da177e4 LT |
851 | } |
852 | s->s_flags |= MS_ACTIVE; | |
853 | } | |
854 | do_remount_sb(s, flags, data, 0); | |
a3ec947c SB |
855 | simple_set_mnt(mnt, s); |
856 | return 0; | |
1da177e4 LT |
857 | } |
858 | ||
859 | EXPORT_SYMBOL(get_sb_single); | |
860 | ||
861 | struct vfsmount * | |
bb4a58bf | 862 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 863 | { |
1da177e4 | 864 | struct vfsmount *mnt; |
1da177e4 | 865 | char *secdata = NULL; |
454e2398 | 866 | int error; |
1da177e4 LT |
867 | |
868 | if (!type) | |
869 | return ERR_PTR(-ENODEV); | |
1da177e4 | 870 | |
454e2398 | 871 | error = -ENOMEM; |
1da177e4 LT |
872 | mnt = alloc_vfsmnt(name); |
873 | if (!mnt) | |
874 | goto out; | |
875 | ||
e0007529 | 876 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 877 | secdata = alloc_secdata(); |
454e2398 | 878 | if (!secdata) |
1da177e4 | 879 | goto out_mnt; |
1da177e4 | 880 | |
e0007529 | 881 | error = security_sb_copy_data(data, secdata); |
454e2398 | 882 | if (error) |
1da177e4 | 883 | goto out_free_secdata; |
1da177e4 LT |
884 | } |
885 | ||
454e2398 DH |
886 | error = type->get_sb(type, flags, name, data, mnt); |
887 | if (error < 0) | |
1da177e4 | 888 | goto out_free_secdata; |
b4c07bce | 889 | BUG_ON(!mnt->mnt_sb); |
454e2398 | 890 | |
12204e24 | 891 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
1da177e4 LT |
892 | if (error) |
893 | goto out_sb; | |
454e2398 DH |
894 | |
895 | mnt->mnt_mountpoint = mnt->mnt_root; | |
1da177e4 | 896 | mnt->mnt_parent = mnt; |
454e2398 | 897 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 898 | free_secdata(secdata); |
1da177e4 LT |
899 | return mnt; |
900 | out_sb: | |
454e2398 | 901 | dput(mnt->mnt_root); |
74dbbdd7 | 902 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
903 | out_free_secdata: |
904 | free_secdata(secdata); | |
905 | out_mnt: | |
906 | free_vfsmnt(mnt); | |
907 | out: | |
454e2398 | 908 | return ERR_PTR(error); |
1da177e4 LT |
909 | } |
910 | ||
bb4a58bf TM |
911 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
912 | ||
79c0b2df MS |
913 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
914 | { | |
915 | int err; | |
916 | const char *subtype = strchr(fstype, '.'); | |
917 | if (subtype) { | |
918 | subtype++; | |
919 | err = -EINVAL; | |
920 | if (!subtype[0]) | |
921 | goto err; | |
922 | } else | |
923 | subtype = ""; | |
924 | ||
925 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
926 | err = -ENOMEM; | |
927 | if (!mnt->mnt_sb->s_subtype) | |
928 | goto err; | |
929 | return mnt; | |
930 | ||
931 | err: | |
932 | mntput(mnt); | |
933 | return ERR_PTR(err); | |
934 | } | |
935 | ||
bb4a58bf TM |
936 | struct vfsmount * |
937 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
938 | { | |
939 | struct file_system_type *type = get_fs_type(fstype); | |
940 | struct vfsmount *mnt; | |
941 | if (!type) | |
942 | return ERR_PTR(-ENODEV); | |
943 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
944 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
945 | !mnt->mnt_sb->s_subtype) | |
946 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
947 | put_filesystem(type); |
948 | return mnt; | |
949 | } | |
8a4e98d9 | 950 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 951 | |
8bf9725c | 952 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 953 | { |
8bf9725c | 954 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
955 | } |
956 | ||
8bf9725c | 957 | EXPORT_SYMBOL_GPL(kern_mount_data); |