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Commit | Line | Data |
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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> | |
31 | #include <linux/buffer_head.h> /* for fsync_super() */ | |
32 | #include <linux/mount.h> | |
33 | #include <linux/security.h> | |
34 | #include <linux/syscalls.h> | |
35 | #include <linux/vfs.h> | |
36 | #include <linux/writeback.h> /* for the emergency remount stuff */ | |
37 | #include <linux/idr.h> | |
38 | #include <linux/kobject.h> | |
353ab6e9 | 39 | #include <linux/mutex.h> |
49e0d02c | 40 | #include <linux/file.h> |
1da177e4 | 41 | #include <asm/uaccess.h> |
6d59e7f5 | 42 | #include "internal.h" |
1da177e4 LT |
43 | |
44 | ||
1da177e4 LT |
45 | LIST_HEAD(super_blocks); |
46 | DEFINE_SPINLOCK(sb_lock); | |
47 | ||
48 | /** | |
49 | * alloc_super - create new superblock | |
fe2bbc48 | 50 | * @type: filesystem type superblock should belong to |
1da177e4 LT |
51 | * |
52 | * Allocates and initializes a new &struct super_block. alloc_super() | |
53 | * returns a pointer new superblock or %NULL if allocation had failed. | |
54 | */ | |
cf516249 | 55 | static struct super_block *alloc_super(struct file_system_type *type) |
1da177e4 | 56 | { |
11b0b5ab | 57 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
1da177e4 LT |
58 | static struct super_operations default_op; |
59 | ||
60 | if (s) { | |
1da177e4 LT |
61 | if (security_sb_alloc(s)) { |
62 | kfree(s); | |
63 | s = NULL; | |
64 | goto out; | |
65 | } | |
66 | INIT_LIST_HEAD(&s->s_dirty); | |
67 | INIT_LIST_HEAD(&s->s_io); | |
0e0f4fc2 | 68 | INIT_LIST_HEAD(&s->s_more_io); |
1da177e4 LT |
69 | INIT_LIST_HEAD(&s->s_files); |
70 | INIT_LIST_HEAD(&s->s_instances); | |
71 | INIT_HLIST_HEAD(&s->s_anon); | |
72 | INIT_LIST_HEAD(&s->s_inodes); | |
da3bbdd4 | 73 | INIT_LIST_HEAD(&s->s_dentry_lru); |
1da177e4 | 74 | init_rwsem(&s->s_umount); |
7892f2f4 | 75 | mutex_init(&s->s_lock); |
897c6ff9 | 76 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
cf516249 IM |
77 | /* |
78 | * The locking rules for s_lock are up to the | |
79 | * filesystem. For example ext3fs has different | |
80 | * lock ordering than usbfs: | |
81 | */ | |
82 | lockdep_set_class(&s->s_lock, &type->s_lock_key); | |
ada723dc PZ |
83 | /* |
84 | * sget() can have s_umount recursion. | |
85 | * | |
86 | * When it cannot find a suitable sb, it allocates a new | |
87 | * one (this one), and tries again to find a suitable old | |
88 | * one. | |
89 | * | |
90 | * In case that succeeds, it will acquire the s_umount | |
91 | * lock of the old one. Since these are clearly distrinct | |
92 | * locks, and this object isn't exposed yet, there's no | |
93 | * risk of deadlocks. | |
94 | * | |
95 | * Annotate this by putting this lock in a different | |
96 | * subclass. | |
97 | */ | |
98 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); | |
1da177e4 LT |
99 | s->s_count = S_BIAS; |
100 | atomic_set(&s->s_active, 1); | |
a11f3a05 | 101 | mutex_init(&s->s_vfs_rename_mutex); |
d3be915f IM |
102 | mutex_init(&s->s_dquot.dqio_mutex); |
103 | mutex_init(&s->s_dquot.dqonoff_mutex); | |
1da177e4 LT |
104 | init_rwsem(&s->s_dquot.dqptr_sem); |
105 | init_waitqueue_head(&s->s_wait_unfrozen); | |
106 | s->s_maxbytes = MAX_NON_LFS; | |
107 | s->dq_op = sb_dquot_ops; | |
108 | s->s_qcop = sb_quotactl_ops; | |
109 | s->s_op = &default_op; | |
110 | s->s_time_gran = 1000000000; | |
111 | } | |
112 | out: | |
113 | return s; | |
114 | } | |
115 | ||
116 | /** | |
117 | * destroy_super - frees a superblock | |
118 | * @s: superblock to free | |
119 | * | |
120 | * Frees a superblock. | |
121 | */ | |
122 | static inline void destroy_super(struct super_block *s) | |
123 | { | |
124 | security_sb_free(s); | |
79c0b2df | 125 | kfree(s->s_subtype); |
b3b304a2 | 126 | kfree(s->s_options); |
1da177e4 LT |
127 | kfree(s); |
128 | } | |
129 | ||
130 | /* Superblock refcounting */ | |
131 | ||
132 | /* | |
133 | * Drop a superblock's refcount. Returns non-zero if the superblock was | |
134 | * destroyed. The caller must hold sb_lock. | |
135 | */ | |
6b09ae66 | 136 | static int __put_super(struct super_block *sb) |
1da177e4 LT |
137 | { |
138 | int ret = 0; | |
139 | ||
140 | if (!--sb->s_count) { | |
141 | destroy_super(sb); | |
142 | ret = 1; | |
143 | } | |
144 | return ret; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Drop a superblock's refcount. | |
149 | * Returns non-zero if the superblock is about to be destroyed and | |
150 | * at least is already removed from super_blocks list, so if we are | |
151 | * making a loop through super blocks then we need to restart. | |
152 | * The caller must hold sb_lock. | |
153 | */ | |
154 | int __put_super_and_need_restart(struct super_block *sb) | |
155 | { | |
156 | /* check for race with generic_shutdown_super() */ | |
157 | if (list_empty(&sb->s_list)) { | |
158 | /* super block is removed, need to restart... */ | |
159 | __put_super(sb); | |
160 | return 1; | |
161 | } | |
162 | /* can't be the last, since s_list is still in use */ | |
163 | sb->s_count--; | |
164 | BUG_ON(sb->s_count == 0); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | /** | |
169 | * put_super - drop a temporary reference to superblock | |
170 | * @sb: superblock in question | |
171 | * | |
172 | * Drops a temporary reference, frees superblock if there's no | |
173 | * references left. | |
174 | */ | |
175 | static void put_super(struct super_block *sb) | |
176 | { | |
177 | spin_lock(&sb_lock); | |
178 | __put_super(sb); | |
179 | spin_unlock(&sb_lock); | |
180 | } | |
181 | ||
182 | ||
183 | /** | |
184 | * deactivate_super - drop an active reference to superblock | |
185 | * @s: superblock to deactivate | |
186 | * | |
187 | * Drops an active reference to superblock, acquiring a temprory one if | |
188 | * there is no active references left. In that case we lock superblock, | |
189 | * tell fs driver to shut it down and drop the temporary reference we | |
190 | * had just acquired. | |
191 | */ | |
192 | void deactivate_super(struct super_block *s) | |
193 | { | |
194 | struct file_system_type *fs = s->s_type; | |
195 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { | |
196 | s->s_count -= S_BIAS-1; | |
197 | spin_unlock(&sb_lock); | |
9e3509e2 | 198 | vfs_dq_off(s, 0); |
1da177e4 LT |
199 | down_write(&s->s_umount); |
200 | fs->kill_sb(s); | |
201 | put_filesystem(fs); | |
202 | put_super(s); | |
203 | } | |
204 | } | |
205 | ||
206 | EXPORT_SYMBOL(deactivate_super); | |
207 | ||
74dbbdd7 AV |
208 | /** |
209 | * deactivate_locked_super - drop an active reference to superblock | |
210 | * @s: superblock to deactivate | |
211 | * | |
212 | * Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that | |
213 | * it does not unlock it until it's all over. As the result, it's safe to | |
214 | * use to dispose of new superblock on ->get_sb() failure exits - nobody | |
215 | * will see the sucker until it's all over. Equivalent using up_write + | |
216 | * deactivate_super is safe for that purpose only if superblock is either | |
217 | * safe to use or has NULL ->s_root when we unlock. | |
218 | */ | |
219 | void deactivate_locked_super(struct super_block *s) | |
220 | { | |
221 | struct file_system_type *fs = s->s_type; | |
222 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { | |
223 | s->s_count -= S_BIAS-1; | |
224 | spin_unlock(&sb_lock); | |
225 | vfs_dq_off(s, 0); | |
226 | fs->kill_sb(s); | |
227 | put_filesystem(fs); | |
228 | put_super(s); | |
229 | } else { | |
230 | up_write(&s->s_umount); | |
231 | } | |
232 | } | |
233 | ||
234 | EXPORT_SYMBOL(deactivate_locked_super); | |
235 | ||
1da177e4 LT |
236 | /** |
237 | * grab_super - acquire an active reference | |
238 | * @s: reference we are trying to make active | |
239 | * | |
240 | * Tries to acquire an active reference. grab_super() is used when we | |
241 | * had just found a superblock in super_blocks or fs_type->fs_supers | |
242 | * and want to turn it into a full-blown active reference. grab_super() | |
243 | * is called with sb_lock held and drops it. Returns 1 in case of | |
244 | * success, 0 if we had failed (superblock contents was already dead or | |
245 | * dying when grab_super() had been called). | |
246 | */ | |
9c4dbee7 | 247 | static int grab_super(struct super_block *s) __releases(sb_lock) |
1da177e4 LT |
248 | { |
249 | s->s_count++; | |
250 | spin_unlock(&sb_lock); | |
251 | down_write(&s->s_umount); | |
252 | if (s->s_root) { | |
253 | spin_lock(&sb_lock); | |
254 | if (s->s_count > S_BIAS) { | |
255 | atomic_inc(&s->s_active); | |
256 | s->s_count--; | |
257 | spin_unlock(&sb_lock); | |
258 | return 1; | |
259 | } | |
260 | spin_unlock(&sb_lock); | |
261 | } | |
262 | up_write(&s->s_umount); | |
263 | put_super(s); | |
264 | yield(); | |
265 | return 0; | |
266 | } | |
267 | ||
914e2637 AV |
268 | /* |
269 | * Superblock locking. We really ought to get rid of these two. | |
270 | */ | |
271 | void lock_super(struct super_block * sb) | |
272 | { | |
273 | get_fs_excl(); | |
274 | mutex_lock(&sb->s_lock); | |
275 | } | |
276 | ||
277 | void unlock_super(struct super_block * sb) | |
278 | { | |
279 | put_fs_excl(); | |
280 | mutex_unlock(&sb->s_lock); | |
281 | } | |
282 | ||
283 | EXPORT_SYMBOL(lock_super); | |
284 | EXPORT_SYMBOL(unlock_super); | |
285 | ||
1da177e4 LT |
286 | /** |
287 | * generic_shutdown_super - common helper for ->kill_sb() | |
288 | * @sb: superblock to kill | |
289 | * | |
290 | * generic_shutdown_super() does all fs-independent work on superblock | |
291 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects | |
292 | * that need destruction out of superblock, call generic_shutdown_super() | |
293 | * and release aforementioned objects. Note: dentries and inodes _are_ | |
294 | * taken care of and do not need specific handling. | |
c636ebdb DH |
295 | * |
296 | * Upon calling this function, the filesystem may no longer alter or | |
297 | * rearrange the set of dentries belonging to this super_block, nor may it | |
298 | * change the attachments of dentries to inodes. | |
1da177e4 LT |
299 | */ |
300 | void generic_shutdown_super(struct super_block *sb) | |
301 | { | |
ee9b6d61 | 302 | const struct super_operations *sop = sb->s_op; |
1da177e4 | 303 | |
efaee192 | 304 | |
c636ebdb DH |
305 | if (sb->s_root) { |
306 | shrink_dcache_for_umount(sb); | |
1da177e4 LT |
307 | fsync_super(sb); |
308 | lock_super(sb); | |
309 | sb->s_flags &= ~MS_ACTIVE; | |
efaee192 | 310 | |
1da177e4 LT |
311 | /* bad name - it should be evict_inodes() */ |
312 | invalidate_inodes(sb); | |
313 | lock_kernel(); | |
314 | ||
315 | if (sop->write_super && sb->s_dirt) | |
316 | sop->write_super(sb); | |
317 | if (sop->put_super) | |
318 | sop->put_super(sb); | |
319 | ||
320 | /* Forget any remaining inodes */ | |
321 | if (invalidate_inodes(sb)) { | |
7b4fe29e DJ |
322 | printk("VFS: Busy inodes after unmount of %s. " |
323 | "Self-destruct in 5 seconds. Have a nice day...\n", | |
324 | sb->s_id); | |
1da177e4 LT |
325 | } |
326 | ||
327 | unlock_kernel(); | |
328 | unlock_super(sb); | |
329 | } | |
330 | spin_lock(&sb_lock); | |
331 | /* should be initialized for __put_super_and_need_restart() */ | |
332 | list_del_init(&sb->s_list); | |
333 | list_del(&sb->s_instances); | |
334 | spin_unlock(&sb_lock); | |
335 | up_write(&sb->s_umount); | |
336 | } | |
337 | ||
338 | EXPORT_SYMBOL(generic_shutdown_super); | |
339 | ||
340 | /** | |
341 | * sget - find or create a superblock | |
342 | * @type: filesystem type superblock should belong to | |
343 | * @test: comparison callback | |
344 | * @set: setup callback | |
345 | * @data: argument to each of them | |
346 | */ | |
347 | struct super_block *sget(struct file_system_type *type, | |
348 | int (*test)(struct super_block *,void *), | |
349 | int (*set)(struct super_block *,void *), | |
350 | void *data) | |
351 | { | |
352 | struct super_block *s = NULL; | |
d4730127 | 353 | struct super_block *old; |
1da177e4 LT |
354 | int err; |
355 | ||
356 | retry: | |
357 | spin_lock(&sb_lock); | |
d4730127 MK |
358 | if (test) { |
359 | list_for_each_entry(old, &type->fs_supers, s_instances) { | |
360 | if (!test(old, data)) | |
361 | continue; | |
362 | if (!grab_super(old)) | |
363 | goto retry; | |
a3cfbb53 LZ |
364 | if (s) { |
365 | up_write(&s->s_umount); | |
d4730127 | 366 | destroy_super(s); |
a3cfbb53 | 367 | } |
d4730127 MK |
368 | return old; |
369 | } | |
1da177e4 LT |
370 | } |
371 | if (!s) { | |
372 | spin_unlock(&sb_lock); | |
cf516249 | 373 | s = alloc_super(type); |
1da177e4 LT |
374 | if (!s) |
375 | return ERR_PTR(-ENOMEM); | |
376 | goto retry; | |
377 | } | |
378 | ||
379 | err = set(s, data); | |
380 | if (err) { | |
381 | spin_unlock(&sb_lock); | |
a3cfbb53 | 382 | up_write(&s->s_umount); |
1da177e4 LT |
383 | destroy_super(s); |
384 | return ERR_PTR(err); | |
385 | } | |
386 | s->s_type = type; | |
387 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
388 | list_add_tail(&s->s_list, &super_blocks); | |
389 | list_add(&s->s_instances, &type->fs_supers); | |
390 | spin_unlock(&sb_lock); | |
391 | get_filesystem(type); | |
392 | return s; | |
393 | } | |
394 | ||
395 | EXPORT_SYMBOL(sget); | |
396 | ||
397 | void drop_super(struct super_block *sb) | |
398 | { | |
399 | up_read(&sb->s_umount); | |
400 | put_super(sb); | |
401 | } | |
402 | ||
403 | EXPORT_SYMBOL(drop_super); | |
404 | ||
405 | static inline void write_super(struct super_block *sb) | |
406 | { | |
407 | lock_super(sb); | |
408 | if (sb->s_root && sb->s_dirt) | |
409 | if (sb->s_op->write_super) | |
410 | sb->s_op->write_super(sb); | |
411 | unlock_super(sb); | |
412 | } | |
413 | ||
414 | /* | |
415 | * Note: check the dirty flag before waiting, so we don't | |
416 | * hold up the sync while mounting a device. (The newly | |
417 | * mounted device won't need syncing.) | |
418 | */ | |
419 | void sync_supers(void) | |
420 | { | |
618f0636 KK |
421 | struct super_block *sb; |
422 | ||
1da177e4 | 423 | spin_lock(&sb_lock); |
618f0636 KK |
424 | restart: |
425 | list_for_each_entry(sb, &super_blocks, s_list) { | |
1da177e4 LT |
426 | if (sb->s_dirt) { |
427 | sb->s_count++; | |
428 | spin_unlock(&sb_lock); | |
429 | down_read(&sb->s_umount); | |
430 | write_super(sb); | |
618f0636 KK |
431 | up_read(&sb->s_umount); |
432 | spin_lock(&sb_lock); | |
433 | if (__put_super_and_need_restart(sb)) | |
434 | goto restart; | |
435 | } | |
436 | } | |
1da177e4 LT |
437 | spin_unlock(&sb_lock); |
438 | } | |
439 | ||
1da177e4 LT |
440 | /** |
441 | * get_super - get the superblock of a device | |
442 | * @bdev: device to get the superblock for | |
443 | * | |
444 | * Scans the superblock list and finds the superblock of the file system | |
445 | * mounted on the device given. %NULL is returned if no match is found. | |
446 | */ | |
447 | ||
448 | struct super_block * get_super(struct block_device *bdev) | |
449 | { | |
618f0636 KK |
450 | struct super_block *sb; |
451 | ||
1da177e4 LT |
452 | if (!bdev) |
453 | return NULL; | |
618f0636 | 454 | |
1da177e4 | 455 | spin_lock(&sb_lock); |
618f0636 KK |
456 | rescan: |
457 | list_for_each_entry(sb, &super_blocks, s_list) { | |
458 | if (sb->s_bdev == bdev) { | |
459 | sb->s_count++; | |
1da177e4 | 460 | spin_unlock(&sb_lock); |
618f0636 KK |
461 | down_read(&sb->s_umount); |
462 | if (sb->s_root) | |
463 | return sb; | |
464 | up_read(&sb->s_umount); | |
465 | /* restart only when sb is no longer on the list */ | |
466 | spin_lock(&sb_lock); | |
467 | if (__put_super_and_need_restart(sb)) | |
468 | goto rescan; | |
1da177e4 LT |
469 | } |
470 | } | |
471 | spin_unlock(&sb_lock); | |
472 | return NULL; | |
473 | } | |
474 | ||
475 | EXPORT_SYMBOL(get_super); | |
476 | ||
477 | struct super_block * user_get_super(dev_t dev) | |
478 | { | |
618f0636 | 479 | struct super_block *sb; |
1da177e4 | 480 | |
1da177e4 | 481 | spin_lock(&sb_lock); |
618f0636 KK |
482 | rescan: |
483 | list_for_each_entry(sb, &super_blocks, s_list) { | |
484 | if (sb->s_dev == dev) { | |
485 | sb->s_count++; | |
1da177e4 | 486 | spin_unlock(&sb_lock); |
618f0636 KK |
487 | down_read(&sb->s_umount); |
488 | if (sb->s_root) | |
489 | return sb; | |
490 | up_read(&sb->s_umount); | |
491 | /* restart only when sb is no longer on the list */ | |
492 | spin_lock(&sb_lock); | |
493 | if (__put_super_and_need_restart(sb)) | |
494 | goto rescan; | |
1da177e4 LT |
495 | } |
496 | } | |
497 | spin_unlock(&sb_lock); | |
498 | return NULL; | |
499 | } | |
500 | ||
257ac264 | 501 | SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) |
1da177e4 LT |
502 | { |
503 | struct super_block *s; | |
504 | struct ustat tmp; | |
505 | struct kstatfs sbuf; | |
506 | int err = -EINVAL; | |
507 | ||
508 | s = user_get_super(new_decode_dev(dev)); | |
509 | if (s == NULL) | |
510 | goto out; | |
726c3342 | 511 | err = vfs_statfs(s->s_root, &sbuf); |
1da177e4 LT |
512 | drop_super(s); |
513 | if (err) | |
514 | goto out; | |
515 | ||
516 | memset(&tmp,0,sizeof(struct ustat)); | |
517 | tmp.f_tfree = sbuf.f_bfree; | |
518 | tmp.f_tinode = sbuf.f_ffree; | |
519 | ||
520 | err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; | |
521 | out: | |
522 | return err; | |
523 | } | |
524 | ||
1da177e4 LT |
525 | /** |
526 | * do_remount_sb - asks filesystem to change mount options. | |
527 | * @sb: superblock in question | |
528 | * @flags: numeric part of options | |
529 | * @data: the rest of options | |
530 | * @force: whether or not to force the change | |
531 | * | |
532 | * Alters the mount options of a mounted file system. | |
533 | */ | |
534 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
535 | { | |
536 | int retval; | |
0ff5af83 | 537 | int remount_rw; |
1da177e4 | 538 | |
9361401e | 539 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
540 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
541 | return -EACCES; | |
9361401e | 542 | #endif |
1da177e4 LT |
543 | if (flags & MS_RDONLY) |
544 | acct_auto_close(sb); | |
545 | shrink_dcache_sb(sb); | |
546 | fsync_super(sb); | |
547 | ||
548 | /* If we are remounting RDONLY and current sb is read/write, | |
549 | make sure there are no rw files opened */ | |
550 | if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { | |
551 | if (force) | |
552 | mark_files_ro(sb); | |
553 | else if (!fs_may_remount_ro(sb)) | |
554 | return -EBUSY; | |
9e3509e2 | 555 | retval = vfs_dq_off(sb, 1); |
0ff5af83 JK |
556 | if (retval < 0 && retval != -ENOSYS) |
557 | return -EBUSY; | |
1da177e4 | 558 | } |
0ff5af83 | 559 | remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY); |
1da177e4 LT |
560 | |
561 | if (sb->s_op->remount_fs) { | |
562 | lock_super(sb); | |
563 | retval = sb->s_op->remount_fs(sb, &flags, data); | |
564 | unlock_super(sb); | |
565 | if (retval) | |
566 | return retval; | |
567 | } | |
568 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
0ff5af83 | 569 | if (remount_rw) |
9e3509e2 | 570 | vfs_dq_quota_on_remount(sb); |
1da177e4 LT |
571 | return 0; |
572 | } | |
573 | ||
a2a9537a | 574 | static void do_emergency_remount(struct work_struct *work) |
1da177e4 LT |
575 | { |
576 | struct super_block *sb; | |
577 | ||
578 | spin_lock(&sb_lock); | |
579 | list_for_each_entry(sb, &super_blocks, s_list) { | |
580 | sb->s_count++; | |
581 | spin_unlock(&sb_lock); | |
582 | down_read(&sb->s_umount); | |
583 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { | |
584 | /* | |
585 | * ->remount_fs needs lock_kernel(). | |
586 | * | |
587 | * What lock protects sb->s_flags?? | |
588 | */ | |
589 | lock_kernel(); | |
590 | do_remount_sb(sb, MS_RDONLY, NULL, 1); | |
591 | unlock_kernel(); | |
592 | } | |
593 | drop_super(sb); | |
594 | spin_lock(&sb_lock); | |
595 | } | |
596 | spin_unlock(&sb_lock); | |
a2a9537a | 597 | kfree(work); |
1da177e4 LT |
598 | printk("Emergency Remount complete\n"); |
599 | } | |
600 | ||
601 | void emergency_remount(void) | |
602 | { | |
a2a9537a JA |
603 | struct work_struct *work; |
604 | ||
605 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
606 | if (work) { | |
607 | INIT_WORK(work, do_emergency_remount); | |
608 | schedule_work(work); | |
609 | } | |
1da177e4 LT |
610 | } |
611 | ||
612 | /* | |
613 | * Unnamed block devices are dummy devices used by virtual | |
614 | * filesystems which don't use real block-devices. -- jrs | |
615 | */ | |
616 | ||
ad76cbc6 | 617 | static DEFINE_IDA(unnamed_dev_ida); |
1da177e4 LT |
618 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
619 | ||
620 | int set_anon_super(struct super_block *s, void *data) | |
621 | { | |
622 | int dev; | |
623 | int error; | |
624 | ||
625 | retry: | |
ad76cbc6 | 626 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
1da177e4 LT |
627 | return -ENOMEM; |
628 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 629 | error = ida_get_new(&unnamed_dev_ida, &dev); |
1da177e4 LT |
630 | spin_unlock(&unnamed_dev_lock); |
631 | if (error == -EAGAIN) | |
632 | /* We raced and lost with another CPU. */ | |
633 | goto retry; | |
634 | else if (error) | |
635 | return -EAGAIN; | |
636 | ||
637 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
638 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 639 | ida_remove(&unnamed_dev_ida, dev); |
1da177e4 LT |
640 | spin_unlock(&unnamed_dev_lock); |
641 | return -EMFILE; | |
642 | } | |
643 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
644 | return 0; | |
645 | } | |
646 | ||
647 | EXPORT_SYMBOL(set_anon_super); | |
648 | ||
649 | void kill_anon_super(struct super_block *sb) | |
650 | { | |
651 | int slot = MINOR(sb->s_dev); | |
652 | ||
653 | generic_shutdown_super(sb); | |
654 | spin_lock(&unnamed_dev_lock); | |
ad76cbc6 | 655 | ida_remove(&unnamed_dev_ida, slot); |
1da177e4 LT |
656 | spin_unlock(&unnamed_dev_lock); |
657 | } | |
658 | ||
659 | EXPORT_SYMBOL(kill_anon_super); | |
660 | ||
1da177e4 LT |
661 | void kill_litter_super(struct super_block *sb) |
662 | { | |
663 | if (sb->s_root) | |
664 | d_genocide(sb->s_root); | |
665 | kill_anon_super(sb); | |
666 | } | |
667 | ||
668 | EXPORT_SYMBOL(kill_litter_super); | |
669 | ||
909e6d94 SH |
670 | static int ns_test_super(struct super_block *sb, void *data) |
671 | { | |
672 | return sb->s_fs_info == data; | |
673 | } | |
674 | ||
675 | static int ns_set_super(struct super_block *sb, void *data) | |
676 | { | |
677 | sb->s_fs_info = data; | |
678 | return set_anon_super(sb, NULL); | |
679 | } | |
680 | ||
681 | int get_sb_ns(struct file_system_type *fs_type, int flags, void *data, | |
682 | int (*fill_super)(struct super_block *, void *, int), | |
683 | struct vfsmount *mnt) | |
684 | { | |
685 | struct super_block *sb; | |
686 | ||
687 | sb = sget(fs_type, ns_test_super, ns_set_super, data); | |
688 | if (IS_ERR(sb)) | |
689 | return PTR_ERR(sb); | |
690 | ||
691 | if (!sb->s_root) { | |
692 | int err; | |
693 | sb->s_flags = flags; | |
694 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
695 | if (err) { | |
74dbbdd7 | 696 | deactivate_locked_super(sb); |
909e6d94 SH |
697 | return err; |
698 | } | |
699 | ||
700 | sb->s_flags |= MS_ACTIVE; | |
701 | } | |
702 | ||
703 | simple_set_mnt(mnt, sb); | |
704 | return 0; | |
705 | } | |
706 | ||
707 | EXPORT_SYMBOL(get_sb_ns); | |
708 | ||
9361401e | 709 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
710 | static int set_bdev_super(struct super_block *s, void *data) |
711 | { | |
712 | s->s_bdev = data; | |
713 | s->s_dev = s->s_bdev->bd_dev; | |
714 | return 0; | |
715 | } | |
716 | ||
717 | static int test_bdev_super(struct super_block *s, void *data) | |
718 | { | |
719 | return (void *)s->s_bdev == data; | |
720 | } | |
721 | ||
454e2398 | 722 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 723 | int flags, const char *dev_name, void *data, |
454e2398 DH |
724 | int (*fill_super)(struct super_block *, void *, int), |
725 | struct vfsmount *mnt) | |
1da177e4 LT |
726 | { |
727 | struct block_device *bdev; | |
728 | struct super_block *s; | |
30c40d2c | 729 | fmode_t mode = FMODE_READ; |
1da177e4 LT |
730 | int error = 0; |
731 | ||
30c40d2c AV |
732 | if (!(flags & MS_RDONLY)) |
733 | mode |= FMODE_WRITE; | |
734 | ||
735 | bdev = open_bdev_exclusive(dev_name, mode, fs_type); | |
1da177e4 | 736 | if (IS_ERR(bdev)) |
454e2398 | 737 | return PTR_ERR(bdev); |
1da177e4 LT |
738 | |
739 | /* | |
740 | * once the super is inserted into the list by sget, s_umount | |
741 | * will protect the lockfs code from trying to start a snapshot | |
742 | * while we are mounting | |
743 | */ | |
f73ca1b7 | 744 | down(&bdev->bd_mount_sem); |
1da177e4 | 745 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
f73ca1b7 | 746 | up(&bdev->bd_mount_sem); |
1da177e4 | 747 | if (IS_ERR(s)) |
454e2398 | 748 | goto error_s; |
1da177e4 LT |
749 | |
750 | if (s->s_root) { | |
751 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
74dbbdd7 | 752 | deactivate_locked_super(s); |
454e2398 DH |
753 | error = -EBUSY; |
754 | goto error_bdev; | |
1da177e4 | 755 | } |
454e2398 | 756 | |
30c40d2c | 757 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
758 | } else { |
759 | char b[BDEVNAME_SIZE]; | |
760 | ||
761 | s->s_flags = flags; | |
30c40d2c | 762 | s->s_mode = mode; |
1da177e4 | 763 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
e78c9a00 | 764 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 765 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 766 | if (error) { |
74dbbdd7 | 767 | deactivate_locked_super(s); |
454e2398 | 768 | goto error; |
fa675765 | 769 | } |
454e2398 DH |
770 | |
771 | s->s_flags |= MS_ACTIVE; | |
87d8fe1e | 772 | bdev->bd_super = s; |
1da177e4 LT |
773 | } |
774 | ||
a3ec947c SB |
775 | simple_set_mnt(mnt, s); |
776 | return 0; | |
1da177e4 | 777 | |
454e2398 DH |
778 | error_s: |
779 | error = PTR_ERR(s); | |
780 | error_bdev: | |
30c40d2c | 781 | close_bdev_exclusive(bdev, mode); |
454e2398 DH |
782 | error: |
783 | return error; | |
1da177e4 LT |
784 | } |
785 | ||
786 | EXPORT_SYMBOL(get_sb_bdev); | |
787 | ||
788 | void kill_block_super(struct super_block *sb) | |
789 | { | |
790 | struct block_device *bdev = sb->s_bdev; | |
30c40d2c | 791 | fmode_t mode = sb->s_mode; |
1da177e4 | 792 | |
ddbaaf30 | 793 | bdev->bd_super = NULL; |
1da177e4 LT |
794 | generic_shutdown_super(sb); |
795 | sync_blockdev(bdev); | |
30c40d2c | 796 | close_bdev_exclusive(bdev, mode); |
1da177e4 LT |
797 | } |
798 | ||
799 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 800 | #endif |
1da177e4 | 801 | |
454e2398 | 802 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 803 | int flags, void *data, |
454e2398 DH |
804 | int (*fill_super)(struct super_block *, void *, int), |
805 | struct vfsmount *mnt) | |
1da177e4 LT |
806 | { |
807 | int error; | |
808 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
809 | ||
810 | if (IS_ERR(s)) | |
454e2398 | 811 | return PTR_ERR(s); |
1da177e4 LT |
812 | |
813 | s->s_flags = flags; | |
814 | ||
9b04c997 | 815 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 816 | if (error) { |
74dbbdd7 | 817 | deactivate_locked_super(s); |
454e2398 | 818 | return error; |
1da177e4 LT |
819 | } |
820 | s->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
821 | simple_set_mnt(mnt, s); |
822 | return 0; | |
1da177e4 LT |
823 | } |
824 | ||
825 | EXPORT_SYMBOL(get_sb_nodev); | |
826 | ||
827 | static int compare_single(struct super_block *s, void *p) | |
828 | { | |
829 | return 1; | |
830 | } | |
831 | ||
454e2398 | 832 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 833 | int flags, void *data, |
454e2398 DH |
834 | int (*fill_super)(struct super_block *, void *, int), |
835 | struct vfsmount *mnt) | |
1da177e4 LT |
836 | { |
837 | struct super_block *s; | |
838 | int error; | |
839 | ||
840 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
841 | if (IS_ERR(s)) | |
454e2398 | 842 | return PTR_ERR(s); |
1da177e4 LT |
843 | if (!s->s_root) { |
844 | s->s_flags = flags; | |
9b04c997 | 845 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 | 846 | if (error) { |
74dbbdd7 | 847 | deactivate_locked_super(s); |
454e2398 | 848 | return error; |
1da177e4 LT |
849 | } |
850 | s->s_flags |= MS_ACTIVE; | |
851 | } | |
852 | do_remount_sb(s, flags, data, 0); | |
a3ec947c SB |
853 | simple_set_mnt(mnt, s); |
854 | return 0; | |
1da177e4 LT |
855 | } |
856 | ||
857 | EXPORT_SYMBOL(get_sb_single); | |
858 | ||
859 | struct vfsmount * | |
bb4a58bf | 860 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 861 | { |
1da177e4 | 862 | struct vfsmount *mnt; |
1da177e4 | 863 | char *secdata = NULL; |
454e2398 | 864 | int error; |
1da177e4 LT |
865 | |
866 | if (!type) | |
867 | return ERR_PTR(-ENODEV); | |
1da177e4 | 868 | |
454e2398 | 869 | error = -ENOMEM; |
1da177e4 LT |
870 | mnt = alloc_vfsmnt(name); |
871 | if (!mnt) | |
872 | goto out; | |
873 | ||
e0007529 | 874 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 875 | secdata = alloc_secdata(); |
454e2398 | 876 | if (!secdata) |
1da177e4 | 877 | goto out_mnt; |
1da177e4 | 878 | |
e0007529 | 879 | error = security_sb_copy_data(data, secdata); |
454e2398 | 880 | if (error) |
1da177e4 | 881 | goto out_free_secdata; |
1da177e4 LT |
882 | } |
883 | ||
454e2398 DH |
884 | error = type->get_sb(type, flags, name, data, mnt); |
885 | if (error < 0) | |
1da177e4 | 886 | goto out_free_secdata; |
b4c07bce | 887 | BUG_ON(!mnt->mnt_sb); |
454e2398 | 888 | |
12204e24 | 889 | error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); |
1da177e4 LT |
890 | if (error) |
891 | goto out_sb; | |
454e2398 DH |
892 | |
893 | mnt->mnt_mountpoint = mnt->mnt_root; | |
1da177e4 | 894 | mnt->mnt_parent = mnt; |
454e2398 | 895 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 896 | free_secdata(secdata); |
1da177e4 LT |
897 | return mnt; |
898 | out_sb: | |
454e2398 | 899 | dput(mnt->mnt_root); |
74dbbdd7 | 900 | deactivate_locked_super(mnt->mnt_sb); |
1da177e4 LT |
901 | out_free_secdata: |
902 | free_secdata(secdata); | |
903 | out_mnt: | |
904 | free_vfsmnt(mnt); | |
905 | out: | |
454e2398 | 906 | return ERR_PTR(error); |
1da177e4 LT |
907 | } |
908 | ||
bb4a58bf TM |
909 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
910 | ||
79c0b2df MS |
911 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
912 | { | |
913 | int err; | |
914 | const char *subtype = strchr(fstype, '.'); | |
915 | if (subtype) { | |
916 | subtype++; | |
917 | err = -EINVAL; | |
918 | if (!subtype[0]) | |
919 | goto err; | |
920 | } else | |
921 | subtype = ""; | |
922 | ||
923 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
924 | err = -ENOMEM; | |
925 | if (!mnt->mnt_sb->s_subtype) | |
926 | goto err; | |
927 | return mnt; | |
928 | ||
929 | err: | |
930 | mntput(mnt); | |
931 | return ERR_PTR(err); | |
932 | } | |
933 | ||
bb4a58bf TM |
934 | struct vfsmount * |
935 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
936 | { | |
937 | struct file_system_type *type = get_fs_type(fstype); | |
938 | struct vfsmount *mnt; | |
939 | if (!type) | |
940 | return ERR_PTR(-ENODEV); | |
941 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
942 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
943 | !mnt->mnt_sb->s_subtype) | |
944 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
945 | put_filesystem(type); |
946 | return mnt; | |
947 | } | |
8a4e98d9 | 948 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 949 | |
8bf9725c | 950 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 951 | { |
8bf9725c | 952 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
953 | } |
954 | ||
8bf9725c | 955 | EXPORT_SYMBOL_GPL(kern_mount_data); |