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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 LT |
41 | #include <asm/uaccess.h> |
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); | |
72 | init_rwsem(&s->s_umount); | |
7892f2f4 | 73 | mutex_init(&s->s_lock); |
897c6ff9 | 74 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
cf516249 IM |
75 | /* |
76 | * The locking rules for s_lock are up to the | |
77 | * filesystem. For example ext3fs has different | |
78 | * lock ordering than usbfs: | |
79 | */ | |
80 | lockdep_set_class(&s->s_lock, &type->s_lock_key); | |
1da177e4 LT |
81 | down_write(&s->s_umount); |
82 | s->s_count = S_BIAS; | |
83 | atomic_set(&s->s_active, 1); | |
a11f3a05 | 84 | mutex_init(&s->s_vfs_rename_mutex); |
d3be915f IM |
85 | mutex_init(&s->s_dquot.dqio_mutex); |
86 | mutex_init(&s->s_dquot.dqonoff_mutex); | |
1da177e4 LT |
87 | init_rwsem(&s->s_dquot.dqptr_sem); |
88 | init_waitqueue_head(&s->s_wait_unfrozen); | |
89 | s->s_maxbytes = MAX_NON_LFS; | |
90 | s->dq_op = sb_dquot_ops; | |
91 | s->s_qcop = sb_quotactl_ops; | |
92 | s->s_op = &default_op; | |
93 | s->s_time_gran = 1000000000; | |
94 | } | |
95 | out: | |
96 | return s; | |
97 | } | |
98 | ||
99 | /** | |
100 | * destroy_super - frees a superblock | |
101 | * @s: superblock to free | |
102 | * | |
103 | * Frees a superblock. | |
104 | */ | |
105 | static inline void destroy_super(struct super_block *s) | |
106 | { | |
107 | security_sb_free(s); | |
79c0b2df | 108 | kfree(s->s_subtype); |
b3b304a2 | 109 | kfree(s->s_options); |
1da177e4 LT |
110 | kfree(s); |
111 | } | |
112 | ||
113 | /* Superblock refcounting */ | |
114 | ||
115 | /* | |
116 | * Drop a superblock's refcount. Returns non-zero if the superblock was | |
117 | * destroyed. The caller must hold sb_lock. | |
118 | */ | |
119 | int __put_super(struct super_block *sb) | |
120 | { | |
121 | int ret = 0; | |
122 | ||
123 | if (!--sb->s_count) { | |
124 | destroy_super(sb); | |
125 | ret = 1; | |
126 | } | |
127 | return ret; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Drop a superblock's refcount. | |
132 | * Returns non-zero if the superblock is about to be destroyed and | |
133 | * at least is already removed from super_blocks list, so if we are | |
134 | * making a loop through super blocks then we need to restart. | |
135 | * The caller must hold sb_lock. | |
136 | */ | |
137 | int __put_super_and_need_restart(struct super_block *sb) | |
138 | { | |
139 | /* check for race with generic_shutdown_super() */ | |
140 | if (list_empty(&sb->s_list)) { | |
141 | /* super block is removed, need to restart... */ | |
142 | __put_super(sb); | |
143 | return 1; | |
144 | } | |
145 | /* can't be the last, since s_list is still in use */ | |
146 | sb->s_count--; | |
147 | BUG_ON(sb->s_count == 0); | |
148 | return 0; | |
149 | } | |
150 | ||
151 | /** | |
152 | * put_super - drop a temporary reference to superblock | |
153 | * @sb: superblock in question | |
154 | * | |
155 | * Drops a temporary reference, frees superblock if there's no | |
156 | * references left. | |
157 | */ | |
158 | static void put_super(struct super_block *sb) | |
159 | { | |
160 | spin_lock(&sb_lock); | |
161 | __put_super(sb); | |
162 | spin_unlock(&sb_lock); | |
163 | } | |
164 | ||
165 | ||
166 | /** | |
167 | * deactivate_super - drop an active reference to superblock | |
168 | * @s: superblock to deactivate | |
169 | * | |
170 | * Drops an active reference to superblock, acquiring a temprory one if | |
171 | * there is no active references left. In that case we lock superblock, | |
172 | * tell fs driver to shut it down and drop the temporary reference we | |
173 | * had just acquired. | |
174 | */ | |
175 | void deactivate_super(struct super_block *s) | |
176 | { | |
177 | struct file_system_type *fs = s->s_type; | |
178 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { | |
179 | s->s_count -= S_BIAS-1; | |
180 | spin_unlock(&sb_lock); | |
7b7b1ace | 181 | DQUOT_OFF(s); |
1da177e4 LT |
182 | down_write(&s->s_umount); |
183 | fs->kill_sb(s); | |
184 | put_filesystem(fs); | |
185 | put_super(s); | |
186 | } | |
187 | } | |
188 | ||
189 | EXPORT_SYMBOL(deactivate_super); | |
190 | ||
191 | /** | |
192 | * grab_super - acquire an active reference | |
193 | * @s: reference we are trying to make active | |
194 | * | |
195 | * Tries to acquire an active reference. grab_super() is used when we | |
196 | * had just found a superblock in super_blocks or fs_type->fs_supers | |
197 | * and want to turn it into a full-blown active reference. grab_super() | |
198 | * is called with sb_lock held and drops it. Returns 1 in case of | |
199 | * success, 0 if we had failed (superblock contents was already dead or | |
200 | * dying when grab_super() had been called). | |
201 | */ | |
9c4dbee7 | 202 | static int grab_super(struct super_block *s) __releases(sb_lock) |
1da177e4 LT |
203 | { |
204 | s->s_count++; | |
205 | spin_unlock(&sb_lock); | |
206 | down_write(&s->s_umount); | |
207 | if (s->s_root) { | |
208 | spin_lock(&sb_lock); | |
209 | if (s->s_count > S_BIAS) { | |
210 | atomic_inc(&s->s_active); | |
211 | s->s_count--; | |
212 | spin_unlock(&sb_lock); | |
213 | return 1; | |
214 | } | |
215 | spin_unlock(&sb_lock); | |
216 | } | |
217 | up_write(&s->s_umount); | |
218 | put_super(s); | |
219 | yield(); | |
220 | return 0; | |
221 | } | |
222 | ||
914e2637 AV |
223 | /* |
224 | * Superblock locking. We really ought to get rid of these two. | |
225 | */ | |
226 | void lock_super(struct super_block * sb) | |
227 | { | |
228 | get_fs_excl(); | |
229 | mutex_lock(&sb->s_lock); | |
230 | } | |
231 | ||
232 | void unlock_super(struct super_block * sb) | |
233 | { | |
234 | put_fs_excl(); | |
235 | mutex_unlock(&sb->s_lock); | |
236 | } | |
237 | ||
238 | EXPORT_SYMBOL(lock_super); | |
239 | EXPORT_SYMBOL(unlock_super); | |
240 | ||
cf9a2ae8 DH |
241 | /* |
242 | * Write out and wait upon all dirty data associated with this | |
243 | * superblock. Filesystem data as well as the underlying block | |
244 | * device. Takes the superblock lock. Requires a second blkdev | |
245 | * flush by the caller to complete the operation. | |
246 | */ | |
247 | void __fsync_super(struct super_block *sb) | |
248 | { | |
249 | sync_inodes_sb(sb, 0); | |
250 | DQUOT_SYNC(sb); | |
251 | lock_super(sb); | |
252 | if (sb->s_dirt && sb->s_op->write_super) | |
253 | sb->s_op->write_super(sb); | |
254 | unlock_super(sb); | |
255 | if (sb->s_op->sync_fs) | |
256 | sb->s_op->sync_fs(sb, 1); | |
257 | sync_blockdev(sb->s_bdev); | |
258 | sync_inodes_sb(sb, 1); | |
259 | } | |
260 | ||
261 | /* | |
262 | * Write out and wait upon all dirty data associated with this | |
263 | * superblock. Filesystem data as well as the underlying block | |
264 | * device. Takes the superblock lock. | |
265 | */ | |
266 | int fsync_super(struct super_block *sb) | |
267 | { | |
268 | __fsync_super(sb); | |
269 | return sync_blockdev(sb->s_bdev); | |
270 | } | |
271 | ||
1da177e4 LT |
272 | /** |
273 | * generic_shutdown_super - common helper for ->kill_sb() | |
274 | * @sb: superblock to kill | |
275 | * | |
276 | * generic_shutdown_super() does all fs-independent work on superblock | |
277 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects | |
278 | * that need destruction out of superblock, call generic_shutdown_super() | |
279 | * and release aforementioned objects. Note: dentries and inodes _are_ | |
280 | * taken care of and do not need specific handling. | |
c636ebdb DH |
281 | * |
282 | * Upon calling this function, the filesystem may no longer alter or | |
283 | * rearrange the set of dentries belonging to this super_block, nor may it | |
284 | * change the attachments of dentries to inodes. | |
1da177e4 LT |
285 | */ |
286 | void generic_shutdown_super(struct super_block *sb) | |
287 | { | |
ee9b6d61 | 288 | const struct super_operations *sop = sb->s_op; |
1da177e4 | 289 | |
c636ebdb DH |
290 | if (sb->s_root) { |
291 | shrink_dcache_for_umount(sb); | |
1da177e4 LT |
292 | fsync_super(sb); |
293 | lock_super(sb); | |
294 | sb->s_flags &= ~MS_ACTIVE; | |
295 | /* bad name - it should be evict_inodes() */ | |
296 | invalidate_inodes(sb); | |
297 | lock_kernel(); | |
298 | ||
299 | if (sop->write_super && sb->s_dirt) | |
300 | sop->write_super(sb); | |
301 | if (sop->put_super) | |
302 | sop->put_super(sb); | |
303 | ||
304 | /* Forget any remaining inodes */ | |
305 | if (invalidate_inodes(sb)) { | |
7b4fe29e DJ |
306 | printk("VFS: Busy inodes after unmount of %s. " |
307 | "Self-destruct in 5 seconds. Have a nice day...\n", | |
308 | sb->s_id); | |
1da177e4 LT |
309 | } |
310 | ||
311 | unlock_kernel(); | |
312 | unlock_super(sb); | |
313 | } | |
314 | spin_lock(&sb_lock); | |
315 | /* should be initialized for __put_super_and_need_restart() */ | |
316 | list_del_init(&sb->s_list); | |
317 | list_del(&sb->s_instances); | |
318 | spin_unlock(&sb_lock); | |
319 | up_write(&sb->s_umount); | |
320 | } | |
321 | ||
322 | EXPORT_SYMBOL(generic_shutdown_super); | |
323 | ||
324 | /** | |
325 | * sget - find or create a superblock | |
326 | * @type: filesystem type superblock should belong to | |
327 | * @test: comparison callback | |
328 | * @set: setup callback | |
329 | * @data: argument to each of them | |
330 | */ | |
331 | struct super_block *sget(struct file_system_type *type, | |
332 | int (*test)(struct super_block *,void *), | |
333 | int (*set)(struct super_block *,void *), | |
334 | void *data) | |
335 | { | |
336 | struct super_block *s = NULL; | |
d4730127 | 337 | struct super_block *old; |
1da177e4 LT |
338 | int err; |
339 | ||
340 | retry: | |
341 | spin_lock(&sb_lock); | |
d4730127 MK |
342 | if (test) { |
343 | list_for_each_entry(old, &type->fs_supers, s_instances) { | |
344 | if (!test(old, data)) | |
345 | continue; | |
346 | if (!grab_super(old)) | |
347 | goto retry; | |
348 | if (s) | |
349 | destroy_super(s); | |
350 | return old; | |
351 | } | |
1da177e4 LT |
352 | } |
353 | if (!s) { | |
354 | spin_unlock(&sb_lock); | |
cf516249 | 355 | s = alloc_super(type); |
1da177e4 LT |
356 | if (!s) |
357 | return ERR_PTR(-ENOMEM); | |
358 | goto retry; | |
359 | } | |
360 | ||
361 | err = set(s, data); | |
362 | if (err) { | |
363 | spin_unlock(&sb_lock); | |
364 | destroy_super(s); | |
365 | return ERR_PTR(err); | |
366 | } | |
367 | s->s_type = type; | |
368 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); | |
369 | list_add_tail(&s->s_list, &super_blocks); | |
370 | list_add(&s->s_instances, &type->fs_supers); | |
371 | spin_unlock(&sb_lock); | |
372 | get_filesystem(type); | |
373 | return s; | |
374 | } | |
375 | ||
376 | EXPORT_SYMBOL(sget); | |
377 | ||
378 | void drop_super(struct super_block *sb) | |
379 | { | |
380 | up_read(&sb->s_umount); | |
381 | put_super(sb); | |
382 | } | |
383 | ||
384 | EXPORT_SYMBOL(drop_super); | |
385 | ||
386 | static inline void write_super(struct super_block *sb) | |
387 | { | |
388 | lock_super(sb); | |
389 | if (sb->s_root && sb->s_dirt) | |
390 | if (sb->s_op->write_super) | |
391 | sb->s_op->write_super(sb); | |
392 | unlock_super(sb); | |
393 | } | |
394 | ||
395 | /* | |
396 | * Note: check the dirty flag before waiting, so we don't | |
397 | * hold up the sync while mounting a device. (The newly | |
398 | * mounted device won't need syncing.) | |
399 | */ | |
400 | void sync_supers(void) | |
401 | { | |
618f0636 KK |
402 | struct super_block *sb; |
403 | ||
1da177e4 | 404 | spin_lock(&sb_lock); |
618f0636 KK |
405 | restart: |
406 | list_for_each_entry(sb, &super_blocks, s_list) { | |
1da177e4 LT |
407 | if (sb->s_dirt) { |
408 | sb->s_count++; | |
409 | spin_unlock(&sb_lock); | |
410 | down_read(&sb->s_umount); | |
411 | write_super(sb); | |
618f0636 KK |
412 | up_read(&sb->s_umount); |
413 | spin_lock(&sb_lock); | |
414 | if (__put_super_and_need_restart(sb)) | |
415 | goto restart; | |
416 | } | |
417 | } | |
1da177e4 LT |
418 | spin_unlock(&sb_lock); |
419 | } | |
420 | ||
421 | /* | |
3a4fa0a2 | 422 | * Call the ->sync_fs super_op against all filesystems which are r/w and |
1da177e4 LT |
423 | * which implement it. |
424 | * | |
425 | * This operation is careful to avoid the livelock which could easily happen | |
426 | * if two or more filesystems are being continuously dirtied. s_need_sync_fs | |
427 | * is used only here. We set it against all filesystems and then clear it as | |
428 | * we sync them. So redirtied filesystems are skipped. | |
429 | * | |
3a4fa0a2 | 430 | * But if process A is currently running sync_filesystems and then process B |
1da177e4 LT |
431 | * calls sync_filesystems as well, process B will set all the s_need_sync_fs |
432 | * flags again, which will cause process A to resync everything. Fix that with | |
433 | * a local mutex. | |
434 | * | |
435 | * (Fabian) Avoid sync_fs with clean fs & wait mode 0 | |
436 | */ | |
437 | void sync_filesystems(int wait) | |
438 | { | |
439 | struct super_block *sb; | |
353ab6e9 | 440 | static DEFINE_MUTEX(mutex); |
1da177e4 | 441 | |
353ab6e9 | 442 | mutex_lock(&mutex); /* Could be down_interruptible */ |
1da177e4 | 443 | spin_lock(&sb_lock); |
618f0636 | 444 | list_for_each_entry(sb, &super_blocks, s_list) { |
1da177e4 LT |
445 | if (!sb->s_op->sync_fs) |
446 | continue; | |
447 | if (sb->s_flags & MS_RDONLY) | |
448 | continue; | |
449 | sb->s_need_sync_fs = 1; | |
450 | } | |
1da177e4 LT |
451 | |
452 | restart: | |
618f0636 | 453 | list_for_each_entry(sb, &super_blocks, s_list) { |
1da177e4 LT |
454 | if (!sb->s_need_sync_fs) |
455 | continue; | |
456 | sb->s_need_sync_fs = 0; | |
457 | if (sb->s_flags & MS_RDONLY) | |
458 | continue; /* hm. Was remounted r/o meanwhile */ | |
459 | sb->s_count++; | |
460 | spin_unlock(&sb_lock); | |
461 | down_read(&sb->s_umount); | |
462 | if (sb->s_root && (wait || sb->s_dirt)) | |
463 | sb->s_op->sync_fs(sb, wait); | |
618f0636 KK |
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 restart; | |
1da177e4 LT |
469 | } |
470 | spin_unlock(&sb_lock); | |
353ab6e9 | 471 | mutex_unlock(&mutex); |
1da177e4 LT |
472 | } |
473 | ||
474 | /** | |
475 | * get_super - get the superblock of a device | |
476 | * @bdev: device to get the superblock for | |
477 | * | |
478 | * Scans the superblock list and finds the superblock of the file system | |
479 | * mounted on the device given. %NULL is returned if no match is found. | |
480 | */ | |
481 | ||
482 | struct super_block * get_super(struct block_device *bdev) | |
483 | { | |
618f0636 KK |
484 | struct super_block *sb; |
485 | ||
1da177e4 LT |
486 | if (!bdev) |
487 | return NULL; | |
618f0636 | 488 | |
1da177e4 | 489 | spin_lock(&sb_lock); |
618f0636 KK |
490 | rescan: |
491 | list_for_each_entry(sb, &super_blocks, s_list) { | |
492 | if (sb->s_bdev == bdev) { | |
493 | sb->s_count++; | |
1da177e4 | 494 | spin_unlock(&sb_lock); |
618f0636 KK |
495 | down_read(&sb->s_umount); |
496 | if (sb->s_root) | |
497 | return sb; | |
498 | up_read(&sb->s_umount); | |
499 | /* restart only when sb is no longer on the list */ | |
500 | spin_lock(&sb_lock); | |
501 | if (__put_super_and_need_restart(sb)) | |
502 | goto rescan; | |
1da177e4 LT |
503 | } |
504 | } | |
505 | spin_unlock(&sb_lock); | |
506 | return NULL; | |
507 | } | |
508 | ||
509 | EXPORT_SYMBOL(get_super); | |
510 | ||
511 | struct super_block * user_get_super(dev_t dev) | |
512 | { | |
618f0636 | 513 | struct super_block *sb; |
1da177e4 | 514 | |
1da177e4 | 515 | spin_lock(&sb_lock); |
618f0636 KK |
516 | rescan: |
517 | list_for_each_entry(sb, &super_blocks, s_list) { | |
518 | if (sb->s_dev == dev) { | |
519 | sb->s_count++; | |
1da177e4 | 520 | spin_unlock(&sb_lock); |
618f0636 KK |
521 | down_read(&sb->s_umount); |
522 | if (sb->s_root) | |
523 | return sb; | |
524 | up_read(&sb->s_umount); | |
525 | /* restart only when sb is no longer on the list */ | |
526 | spin_lock(&sb_lock); | |
527 | if (__put_super_and_need_restart(sb)) | |
528 | goto rescan; | |
1da177e4 LT |
529 | } |
530 | } | |
531 | spin_unlock(&sb_lock); | |
532 | return NULL; | |
533 | } | |
534 | ||
1da177e4 LT |
535 | asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf) |
536 | { | |
537 | struct super_block *s; | |
538 | struct ustat tmp; | |
539 | struct kstatfs sbuf; | |
540 | int err = -EINVAL; | |
541 | ||
542 | s = user_get_super(new_decode_dev(dev)); | |
543 | if (s == NULL) | |
544 | goto out; | |
726c3342 | 545 | err = vfs_statfs(s->s_root, &sbuf); |
1da177e4 LT |
546 | drop_super(s); |
547 | if (err) | |
548 | goto out; | |
549 | ||
550 | memset(&tmp,0,sizeof(struct ustat)); | |
551 | tmp.f_tfree = sbuf.f_bfree; | |
552 | tmp.f_tinode = sbuf.f_ffree; | |
553 | ||
554 | err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; | |
555 | out: | |
556 | return err; | |
557 | } | |
558 | ||
559 | /** | |
a6b91919 | 560 | * mark_files_ro - mark all files read-only |
1da177e4 LT |
561 | * @sb: superblock in question |
562 | * | |
a6b91919 RD |
563 | * All files are marked read-only. We don't care about pending |
564 | * delete files so this should be used in 'force' mode only. | |
1da177e4 LT |
565 | */ |
566 | ||
567 | static void mark_files_ro(struct super_block *sb) | |
568 | { | |
569 | struct file *f; | |
570 | ||
49e0d02c | 571 | retry: |
1da177e4 | 572 | file_list_lock(); |
2f512016 | 573 | list_for_each_entry(f, &sb->s_files, f_u.fu_list) { |
49e0d02c DH |
574 | struct vfsmount *mnt; |
575 | if (!S_ISREG(f->f_path.dentry->d_inode->i_mode)) | |
576 | continue; | |
577 | if (!file_count(f)) | |
578 | continue; | |
579 | if (!(f->f_mode & FMODE_WRITE)) | |
580 | continue; | |
581 | f->f_mode &= ~FMODE_WRITE; | |
582 | mnt = mntget(f->f_path.mnt); | |
583 | file_list_unlock(); | |
584 | /* | |
585 | * This can sleep, so we can't hold | |
586 | * the file_list_lock() spinlock. | |
587 | */ | |
588 | mnt_drop_write(mnt); | |
589 | mntput(mnt); | |
590 | goto retry; | |
1da177e4 LT |
591 | } |
592 | file_list_unlock(); | |
593 | } | |
594 | ||
595 | /** | |
596 | * do_remount_sb - asks filesystem to change mount options. | |
597 | * @sb: superblock in question | |
598 | * @flags: numeric part of options | |
599 | * @data: the rest of options | |
600 | * @force: whether or not to force the change | |
601 | * | |
602 | * Alters the mount options of a mounted file system. | |
603 | */ | |
604 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) | |
605 | { | |
606 | int retval; | |
607 | ||
9361401e | 608 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
609 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
610 | return -EACCES; | |
9361401e | 611 | #endif |
1da177e4 LT |
612 | if (flags & MS_RDONLY) |
613 | acct_auto_close(sb); | |
614 | shrink_dcache_sb(sb); | |
615 | fsync_super(sb); | |
616 | ||
617 | /* If we are remounting RDONLY and current sb is read/write, | |
618 | make sure there are no rw files opened */ | |
619 | if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { | |
620 | if (force) | |
621 | mark_files_ro(sb); | |
622 | else if (!fs_may_remount_ro(sb)) | |
623 | return -EBUSY; | |
66191dc6 | 624 | DQUOT_OFF(sb); |
1da177e4 LT |
625 | } |
626 | ||
627 | if (sb->s_op->remount_fs) { | |
628 | lock_super(sb); | |
629 | retval = sb->s_op->remount_fs(sb, &flags, data); | |
630 | unlock_super(sb); | |
631 | if (retval) | |
632 | return retval; | |
633 | } | |
634 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); | |
635 | return 0; | |
636 | } | |
637 | ||
638 | static void do_emergency_remount(unsigned long foo) | |
639 | { | |
640 | struct super_block *sb; | |
641 | ||
642 | spin_lock(&sb_lock); | |
643 | list_for_each_entry(sb, &super_blocks, s_list) { | |
644 | sb->s_count++; | |
645 | spin_unlock(&sb_lock); | |
646 | down_read(&sb->s_umount); | |
647 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { | |
648 | /* | |
649 | * ->remount_fs needs lock_kernel(). | |
650 | * | |
651 | * What lock protects sb->s_flags?? | |
652 | */ | |
653 | lock_kernel(); | |
654 | do_remount_sb(sb, MS_RDONLY, NULL, 1); | |
655 | unlock_kernel(); | |
656 | } | |
657 | drop_super(sb); | |
658 | spin_lock(&sb_lock); | |
659 | } | |
660 | spin_unlock(&sb_lock); | |
661 | printk("Emergency Remount complete\n"); | |
662 | } | |
663 | ||
664 | void emergency_remount(void) | |
665 | { | |
666 | pdflush_operation(do_emergency_remount, 0); | |
667 | } | |
668 | ||
669 | /* | |
670 | * Unnamed block devices are dummy devices used by virtual | |
671 | * filesystems which don't use real block-devices. -- jrs | |
672 | */ | |
673 | ||
674 | static struct idr unnamed_dev_idr; | |
675 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ | |
676 | ||
677 | int set_anon_super(struct super_block *s, void *data) | |
678 | { | |
679 | int dev; | |
680 | int error; | |
681 | ||
682 | retry: | |
683 | if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0) | |
684 | return -ENOMEM; | |
685 | spin_lock(&unnamed_dev_lock); | |
686 | error = idr_get_new(&unnamed_dev_idr, NULL, &dev); | |
687 | spin_unlock(&unnamed_dev_lock); | |
688 | if (error == -EAGAIN) | |
689 | /* We raced and lost with another CPU. */ | |
690 | goto retry; | |
691 | else if (error) | |
692 | return -EAGAIN; | |
693 | ||
694 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { | |
695 | spin_lock(&unnamed_dev_lock); | |
696 | idr_remove(&unnamed_dev_idr, dev); | |
697 | spin_unlock(&unnamed_dev_lock); | |
698 | return -EMFILE; | |
699 | } | |
700 | s->s_dev = MKDEV(0, dev & MINORMASK); | |
701 | return 0; | |
702 | } | |
703 | ||
704 | EXPORT_SYMBOL(set_anon_super); | |
705 | ||
706 | void kill_anon_super(struct super_block *sb) | |
707 | { | |
708 | int slot = MINOR(sb->s_dev); | |
709 | ||
710 | generic_shutdown_super(sb); | |
711 | spin_lock(&unnamed_dev_lock); | |
712 | idr_remove(&unnamed_dev_idr, slot); | |
713 | spin_unlock(&unnamed_dev_lock); | |
714 | } | |
715 | ||
716 | EXPORT_SYMBOL(kill_anon_super); | |
717 | ||
718 | void __init unnamed_dev_init(void) | |
719 | { | |
720 | idr_init(&unnamed_dev_idr); | |
721 | } | |
722 | ||
723 | void kill_litter_super(struct super_block *sb) | |
724 | { | |
725 | if (sb->s_root) | |
726 | d_genocide(sb->s_root); | |
727 | kill_anon_super(sb); | |
728 | } | |
729 | ||
730 | EXPORT_SYMBOL(kill_litter_super); | |
731 | ||
9361401e | 732 | #ifdef CONFIG_BLOCK |
1da177e4 LT |
733 | static int set_bdev_super(struct super_block *s, void *data) |
734 | { | |
735 | s->s_bdev = data; | |
736 | s->s_dev = s->s_bdev->bd_dev; | |
737 | return 0; | |
738 | } | |
739 | ||
740 | static int test_bdev_super(struct super_block *s, void *data) | |
741 | { | |
742 | return (void *)s->s_bdev == data; | |
743 | } | |
744 | ||
454e2398 | 745 | int get_sb_bdev(struct file_system_type *fs_type, |
1da177e4 | 746 | int flags, const char *dev_name, void *data, |
454e2398 DH |
747 | int (*fill_super)(struct super_block *, void *, int), |
748 | struct vfsmount *mnt) | |
1da177e4 LT |
749 | { |
750 | struct block_device *bdev; | |
751 | struct super_block *s; | |
752 | int error = 0; | |
753 | ||
754 | bdev = open_bdev_excl(dev_name, flags, fs_type); | |
755 | if (IS_ERR(bdev)) | |
454e2398 | 756 | return PTR_ERR(bdev); |
1da177e4 LT |
757 | |
758 | /* | |
759 | * once the super is inserted into the list by sget, s_umount | |
760 | * will protect the lockfs code from trying to start a snapshot | |
761 | * while we are mounting | |
762 | */ | |
f73ca1b7 | 763 | down(&bdev->bd_mount_sem); |
1da177e4 | 764 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
f73ca1b7 | 765 | up(&bdev->bd_mount_sem); |
1da177e4 | 766 | if (IS_ERR(s)) |
454e2398 | 767 | goto error_s; |
1da177e4 LT |
768 | |
769 | if (s->s_root) { | |
770 | if ((flags ^ s->s_flags) & MS_RDONLY) { | |
771 | up_write(&s->s_umount); | |
772 | deactivate_super(s); | |
454e2398 DH |
773 | error = -EBUSY; |
774 | goto error_bdev; | |
1da177e4 | 775 | } |
454e2398 DH |
776 | |
777 | close_bdev_excl(bdev); | |
1da177e4 LT |
778 | } else { |
779 | char b[BDEVNAME_SIZE]; | |
780 | ||
781 | s->s_flags = flags; | |
782 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); | |
e78c9a00 | 783 | sb_set_blocksize(s, block_size(bdev)); |
9b04c997 | 784 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 LT |
785 | if (error) { |
786 | up_write(&s->s_umount); | |
787 | deactivate_super(s); | |
454e2398 | 788 | goto error; |
fa675765 | 789 | } |
454e2398 DH |
790 | |
791 | s->s_flags |= MS_ACTIVE; | |
1da177e4 LT |
792 | } |
793 | ||
454e2398 | 794 | return simple_set_mnt(mnt, s); |
1da177e4 | 795 | |
454e2398 DH |
796 | error_s: |
797 | error = PTR_ERR(s); | |
798 | error_bdev: | |
1da177e4 | 799 | close_bdev_excl(bdev); |
454e2398 DH |
800 | error: |
801 | return error; | |
1da177e4 LT |
802 | } |
803 | ||
804 | EXPORT_SYMBOL(get_sb_bdev); | |
805 | ||
806 | void kill_block_super(struct super_block *sb) | |
807 | { | |
808 | struct block_device *bdev = sb->s_bdev; | |
809 | ||
1da177e4 LT |
810 | generic_shutdown_super(sb); |
811 | sync_blockdev(bdev); | |
812 | close_bdev_excl(bdev); | |
813 | } | |
814 | ||
815 | EXPORT_SYMBOL(kill_block_super); | |
9361401e | 816 | #endif |
1da177e4 | 817 | |
454e2398 | 818 | int get_sb_nodev(struct file_system_type *fs_type, |
1da177e4 | 819 | int flags, void *data, |
454e2398 DH |
820 | int (*fill_super)(struct super_block *, void *, int), |
821 | struct vfsmount *mnt) | |
1da177e4 LT |
822 | { |
823 | int error; | |
824 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
825 | ||
826 | if (IS_ERR(s)) | |
454e2398 | 827 | return PTR_ERR(s); |
1da177e4 LT |
828 | |
829 | s->s_flags = flags; | |
830 | ||
9b04c997 | 831 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 LT |
832 | if (error) { |
833 | up_write(&s->s_umount); | |
834 | deactivate_super(s); | |
454e2398 | 835 | return error; |
1da177e4 LT |
836 | } |
837 | s->s_flags |= MS_ACTIVE; | |
454e2398 | 838 | return simple_set_mnt(mnt, s); |
1da177e4 LT |
839 | } |
840 | ||
841 | EXPORT_SYMBOL(get_sb_nodev); | |
842 | ||
843 | static int compare_single(struct super_block *s, void *p) | |
844 | { | |
845 | return 1; | |
846 | } | |
847 | ||
454e2398 | 848 | int get_sb_single(struct file_system_type *fs_type, |
1da177e4 | 849 | int flags, void *data, |
454e2398 DH |
850 | int (*fill_super)(struct super_block *, void *, int), |
851 | struct vfsmount *mnt) | |
1da177e4 LT |
852 | { |
853 | struct super_block *s; | |
854 | int error; | |
855 | ||
856 | s = sget(fs_type, compare_single, set_anon_super, NULL); | |
857 | if (IS_ERR(s)) | |
454e2398 | 858 | return PTR_ERR(s); |
1da177e4 LT |
859 | if (!s->s_root) { |
860 | s->s_flags = flags; | |
9b04c997 | 861 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
1da177e4 LT |
862 | if (error) { |
863 | up_write(&s->s_umount); | |
864 | deactivate_super(s); | |
454e2398 | 865 | return error; |
1da177e4 LT |
866 | } |
867 | s->s_flags |= MS_ACTIVE; | |
868 | } | |
869 | do_remount_sb(s, flags, data, 0); | |
454e2398 | 870 | return simple_set_mnt(mnt, s); |
1da177e4 LT |
871 | } |
872 | ||
873 | EXPORT_SYMBOL(get_sb_single); | |
874 | ||
875 | struct vfsmount * | |
bb4a58bf | 876 | vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) |
1da177e4 | 877 | { |
1da177e4 | 878 | struct vfsmount *mnt; |
1da177e4 | 879 | char *secdata = NULL; |
454e2398 | 880 | int error; |
1da177e4 LT |
881 | |
882 | if (!type) | |
883 | return ERR_PTR(-ENODEV); | |
1da177e4 | 884 | |
454e2398 | 885 | error = -ENOMEM; |
1da177e4 LT |
886 | mnt = alloc_vfsmnt(name); |
887 | if (!mnt) | |
888 | goto out; | |
889 | ||
e0007529 | 890 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
1da177e4 | 891 | secdata = alloc_secdata(); |
454e2398 | 892 | if (!secdata) |
1da177e4 | 893 | goto out_mnt; |
1da177e4 | 894 | |
e0007529 | 895 | error = security_sb_copy_data(data, secdata); |
454e2398 | 896 | if (error) |
1da177e4 | 897 | goto out_free_secdata; |
1da177e4 LT |
898 | } |
899 | ||
454e2398 DH |
900 | error = type->get_sb(type, flags, name, data, mnt); |
901 | if (error < 0) | |
1da177e4 | 902 | goto out_free_secdata; |
b4c07bce | 903 | BUG_ON(!mnt->mnt_sb); |
454e2398 DH |
904 | |
905 | error = security_sb_kern_mount(mnt->mnt_sb, secdata); | |
1da177e4 LT |
906 | if (error) |
907 | goto out_sb; | |
454e2398 DH |
908 | |
909 | mnt->mnt_mountpoint = mnt->mnt_root; | |
1da177e4 | 910 | mnt->mnt_parent = mnt; |
454e2398 | 911 | up_write(&mnt->mnt_sb->s_umount); |
8680e22f | 912 | free_secdata(secdata); |
1da177e4 LT |
913 | return mnt; |
914 | out_sb: | |
454e2398 DH |
915 | dput(mnt->mnt_root); |
916 | up_write(&mnt->mnt_sb->s_umount); | |
917 | deactivate_super(mnt->mnt_sb); | |
1da177e4 LT |
918 | out_free_secdata: |
919 | free_secdata(secdata); | |
920 | out_mnt: | |
921 | free_vfsmnt(mnt); | |
922 | out: | |
454e2398 | 923 | return ERR_PTR(error); |
1da177e4 LT |
924 | } |
925 | ||
bb4a58bf TM |
926 | EXPORT_SYMBOL_GPL(vfs_kern_mount); |
927 | ||
79c0b2df MS |
928 | static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) |
929 | { | |
930 | int err; | |
931 | const char *subtype = strchr(fstype, '.'); | |
932 | if (subtype) { | |
933 | subtype++; | |
934 | err = -EINVAL; | |
935 | if (!subtype[0]) | |
936 | goto err; | |
937 | } else | |
938 | subtype = ""; | |
939 | ||
940 | mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); | |
941 | err = -ENOMEM; | |
942 | if (!mnt->mnt_sb->s_subtype) | |
943 | goto err; | |
944 | return mnt; | |
945 | ||
946 | err: | |
947 | mntput(mnt); | |
948 | return ERR_PTR(err); | |
949 | } | |
950 | ||
bb4a58bf TM |
951 | struct vfsmount * |
952 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) | |
953 | { | |
954 | struct file_system_type *type = get_fs_type(fstype); | |
955 | struct vfsmount *mnt; | |
956 | if (!type) | |
957 | return ERR_PTR(-ENODEV); | |
958 | mnt = vfs_kern_mount(type, flags, name, data); | |
79c0b2df MS |
959 | if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && |
960 | !mnt->mnt_sb->s_subtype) | |
961 | mnt = fs_set_subtype(mnt, fstype); | |
bb4a58bf TM |
962 | put_filesystem(type); |
963 | return mnt; | |
964 | } | |
8a4e98d9 | 965 | EXPORT_SYMBOL_GPL(do_kern_mount); |
bb4a58bf | 966 | |
8bf9725c | 967 | struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) |
1da177e4 | 968 | { |
8bf9725c | 969 | return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); |
1da177e4 LT |
970 | } |
971 | ||
8bf9725c | 972 | EXPORT_SYMBOL_GPL(kern_mount_data); |