Root/
Source at commit b05a5adf03613de371c77c3235f7d970d7cd0c71 created 13 years 1 month ago. By Lars-Peter Clausen, NAND: Optimize reading the eec data for the JZ4740 (evil hack) | |
---|---|
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: |
18 | * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996. |
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 | |
23 | #include <linux/module.h> |
24 | #include <linux/slab.h> |
25 | #include <linux/acct.h> |
26 | #include <linux/blkdev.h> |
27 | #include <linux/mount.h> |
28 | #include <linux/security.h> |
29 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
30 | #include <linux/idr.h> |
31 | #include <linux/mutex.h> |
32 | #include <linux/backing-dev.h> |
33 | #include <linux/rculist_bl.h> |
34 | #include "internal.h" |
35 | |
36 | |
37 | LIST_HEAD(super_blocks); |
38 | DEFINE_SPINLOCK(sb_lock); |
39 | |
40 | /** |
41 | * alloc_super - create new superblock |
42 | * @type: filesystem type superblock should belong to |
43 | * |
44 | * Allocates and initializes a new &struct super_block. alloc_super() |
45 | * returns a pointer new superblock or %NULL if allocation had failed. |
46 | */ |
47 | static struct super_block *alloc_super(struct file_system_type *type) |
48 | { |
49 | struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER); |
50 | static const struct super_operations default_op; |
51 | |
52 | if (s) { |
53 | if (security_sb_alloc(s)) { |
54 | kfree(s); |
55 | s = NULL; |
56 | goto out; |
57 | } |
58 | #ifdef CONFIG_SMP |
59 | s->s_files = alloc_percpu(struct list_head); |
60 | if (!s->s_files) { |
61 | security_sb_free(s); |
62 | kfree(s); |
63 | s = NULL; |
64 | goto out; |
65 | } else { |
66 | int i; |
67 | |
68 | for_each_possible_cpu(i) |
69 | INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i)); |
70 | } |
71 | #else |
72 | INIT_LIST_HEAD(&s->s_files); |
73 | #endif |
74 | s->s_bdi = &default_backing_dev_info; |
75 | INIT_LIST_HEAD(&s->s_instances); |
76 | INIT_HLIST_BL_HEAD(&s->s_anon); |
77 | INIT_LIST_HEAD(&s->s_inodes); |
78 | INIT_LIST_HEAD(&s->s_dentry_lru); |
79 | init_rwsem(&s->s_umount); |
80 | mutex_init(&s->s_lock); |
81 | lockdep_set_class(&s->s_umount, &type->s_umount_key); |
82 | /* |
83 | * The locking rules for s_lock are up to the |
84 | * filesystem. For example ext3fs has different |
85 | * lock ordering than usbfs: |
86 | */ |
87 | lockdep_set_class(&s->s_lock, &type->s_lock_key); |
88 | /* |
89 | * sget() can have s_umount recursion. |
90 | * |
91 | * When it cannot find a suitable sb, it allocates a new |
92 | * one (this one), and tries again to find a suitable old |
93 | * one. |
94 | * |
95 | * In case that succeeds, it will acquire the s_umount |
96 | * lock of the old one. Since these are clearly distrinct |
97 | * locks, and this object isn't exposed yet, there's no |
98 | * risk of deadlocks. |
99 | * |
100 | * Annotate this by putting this lock in a different |
101 | * subclass. |
102 | */ |
103 | down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); |
104 | s->s_count = 1; |
105 | atomic_set(&s->s_active, 1); |
106 | mutex_init(&s->s_vfs_rename_mutex); |
107 | lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key); |
108 | mutex_init(&s->s_dquot.dqio_mutex); |
109 | mutex_init(&s->s_dquot.dqonoff_mutex); |
110 | init_rwsem(&s->s_dquot.dqptr_sem); |
111 | init_waitqueue_head(&s->s_wait_unfrozen); |
112 | s->s_maxbytes = MAX_NON_LFS; |
113 | s->s_op = &default_op; |
114 | s->s_time_gran = 1000000000; |
115 | } |
116 | out: |
117 | return s; |
118 | } |
119 | |
120 | /** |
121 | * destroy_super - frees a superblock |
122 | * @s: superblock to free |
123 | * |
124 | * Frees a superblock. |
125 | */ |
126 | static inline void destroy_super(struct super_block *s) |
127 | { |
128 | #ifdef CONFIG_SMP |
129 | free_percpu(s->s_files); |
130 | #endif |
131 | security_sb_free(s); |
132 | kfree(s->s_subtype); |
133 | kfree(s->s_options); |
134 | kfree(s); |
135 | } |
136 | |
137 | /* Superblock refcounting */ |
138 | |
139 | /* |
140 | * Drop a superblock's refcount. The caller must hold sb_lock. |
141 | */ |
142 | void __put_super(struct super_block *sb) |
143 | { |
144 | if (!--sb->s_count) { |
145 | list_del_init(&sb->s_list); |
146 | destroy_super(sb); |
147 | } |
148 | } |
149 | |
150 | /** |
151 | * put_super - drop a temporary reference to superblock |
152 | * @sb: superblock in question |
153 | * |
154 | * Drops a temporary reference, frees superblock if there's no |
155 | * references left. |
156 | */ |
157 | void put_super(struct super_block *sb) |
158 | { |
159 | spin_lock(&sb_lock); |
160 | __put_super(sb); |
161 | spin_unlock(&sb_lock); |
162 | } |
163 | |
164 | |
165 | /** |
166 | * deactivate_locked_super - drop an active reference to superblock |
167 | * @s: superblock to deactivate |
168 | * |
169 | * Drops an active reference to superblock, converting it into a temprory |
170 | * one if there is no other active references left. In that case we |
171 | * tell fs driver to shut it down and drop the temporary reference we |
172 | * had just acquired. |
173 | * |
174 | * Caller holds exclusive lock on superblock; that lock is released. |
175 | */ |
176 | void deactivate_locked_super(struct super_block *s) |
177 | { |
178 | struct file_system_type *fs = s->s_type; |
179 | if (atomic_dec_and_test(&s->s_active)) { |
180 | fs->kill_sb(s); |
181 | /* |
182 | * We need to call rcu_barrier so all the delayed rcu free |
183 | * inodes are flushed before we release the fs module. |
184 | */ |
185 | rcu_barrier(); |
186 | put_filesystem(fs); |
187 | put_super(s); |
188 | } else { |
189 | up_write(&s->s_umount); |
190 | } |
191 | } |
192 | |
193 | EXPORT_SYMBOL(deactivate_locked_super); |
194 | |
195 | /** |
196 | * deactivate_super - drop an active reference to superblock |
197 | * @s: superblock to deactivate |
198 | * |
199 | * Variant of deactivate_locked_super(), except that superblock is *not* |
200 | * locked by caller. If we are going to drop the final active reference, |
201 | * lock will be acquired prior to that. |
202 | */ |
203 | void deactivate_super(struct super_block *s) |
204 | { |
205 | if (!atomic_add_unless(&s->s_active, -1, 1)) { |
206 | down_write(&s->s_umount); |
207 | deactivate_locked_super(s); |
208 | } |
209 | } |
210 | |
211 | EXPORT_SYMBOL(deactivate_super); |
212 | |
213 | /** |
214 | * grab_super - acquire an active reference |
215 | * @s: reference we are trying to make active |
216 | * |
217 | * Tries to acquire an active reference. grab_super() is used when we |
218 | * had just found a superblock in super_blocks or fs_type->fs_supers |
219 | * and want to turn it into a full-blown active reference. grab_super() |
220 | * is called with sb_lock held and drops it. Returns 1 in case of |
221 | * success, 0 if we had failed (superblock contents was already dead or |
222 | * dying when grab_super() had been called). |
223 | */ |
224 | static int grab_super(struct super_block *s) __releases(sb_lock) |
225 | { |
226 | if (atomic_inc_not_zero(&s->s_active)) { |
227 | spin_unlock(&sb_lock); |
228 | return 1; |
229 | } |
230 | /* it's going away */ |
231 | s->s_count++; |
232 | spin_unlock(&sb_lock); |
233 | /* wait for it to die */ |
234 | down_write(&s->s_umount); |
235 | up_write(&s->s_umount); |
236 | put_super(s); |
237 | return 0; |
238 | } |
239 | |
240 | /* |
241 | * Superblock locking. We really ought to get rid of these two. |
242 | */ |
243 | void lock_super(struct super_block * sb) |
244 | { |
245 | get_fs_excl(); |
246 | mutex_lock(&sb->s_lock); |
247 | } |
248 | |
249 | void unlock_super(struct super_block * sb) |
250 | { |
251 | put_fs_excl(); |
252 | mutex_unlock(&sb->s_lock); |
253 | } |
254 | |
255 | EXPORT_SYMBOL(lock_super); |
256 | EXPORT_SYMBOL(unlock_super); |
257 | |
258 | /** |
259 | * generic_shutdown_super - common helper for ->kill_sb() |
260 | * @sb: superblock to kill |
261 | * |
262 | * generic_shutdown_super() does all fs-independent work on superblock |
263 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects |
264 | * that need destruction out of superblock, call generic_shutdown_super() |
265 | * and release aforementioned objects. Note: dentries and inodes _are_ |
266 | * taken care of and do not need specific handling. |
267 | * |
268 | * Upon calling this function, the filesystem may no longer alter or |
269 | * rearrange the set of dentries belonging to this super_block, nor may it |
270 | * change the attachments of dentries to inodes. |
271 | */ |
272 | void generic_shutdown_super(struct super_block *sb) |
273 | { |
274 | const struct super_operations *sop = sb->s_op; |
275 | |
276 | |
277 | if (sb->s_root) { |
278 | shrink_dcache_for_umount(sb); |
279 | sync_filesystem(sb); |
280 | get_fs_excl(); |
281 | sb->s_flags &= ~MS_ACTIVE; |
282 | |
283 | fsnotify_unmount_inodes(&sb->s_inodes); |
284 | |
285 | evict_inodes(sb); |
286 | |
287 | if (sop->put_super) |
288 | sop->put_super(sb); |
289 | |
290 | if (!list_empty(&sb->s_inodes)) { |
291 | printk("VFS: Busy inodes after unmount of %s. " |
292 | "Self-destruct in 5 seconds. Have a nice day...\n", |
293 | sb->s_id); |
294 | } |
295 | put_fs_excl(); |
296 | } |
297 | spin_lock(&sb_lock); |
298 | /* should be initialized for __put_super_and_need_restart() */ |
299 | list_del_init(&sb->s_instances); |
300 | spin_unlock(&sb_lock); |
301 | up_write(&sb->s_umount); |
302 | } |
303 | |
304 | EXPORT_SYMBOL(generic_shutdown_super); |
305 | |
306 | /** |
307 | * sget - find or create a superblock |
308 | * @type: filesystem type superblock should belong to |
309 | * @test: comparison callback |
310 | * @set: setup callback |
311 | * @data: argument to each of them |
312 | */ |
313 | struct super_block *sget(struct file_system_type *type, |
314 | int (*test)(struct super_block *,void *), |
315 | int (*set)(struct super_block *,void *), |
316 | void *data) |
317 | { |
318 | struct super_block *s = NULL; |
319 | struct super_block *old; |
320 | int err; |
321 | |
322 | retry: |
323 | spin_lock(&sb_lock); |
324 | if (test) { |
325 | list_for_each_entry(old, &type->fs_supers, s_instances) { |
326 | if (!test(old, data)) |
327 | continue; |
328 | if (!grab_super(old)) |
329 | goto retry; |
330 | if (s) { |
331 | up_write(&s->s_umount); |
332 | destroy_super(s); |
333 | s = NULL; |
334 | } |
335 | down_write(&old->s_umount); |
336 | if (unlikely(!(old->s_flags & MS_BORN))) { |
337 | deactivate_locked_super(old); |
338 | goto retry; |
339 | } |
340 | return old; |
341 | } |
342 | } |
343 | if (!s) { |
344 | spin_unlock(&sb_lock); |
345 | s = alloc_super(type); |
346 | if (!s) |
347 | return ERR_PTR(-ENOMEM); |
348 | goto retry; |
349 | } |
350 | |
351 | err = set(s, data); |
352 | if (err) { |
353 | spin_unlock(&sb_lock); |
354 | up_write(&s->s_umount); |
355 | destroy_super(s); |
356 | return ERR_PTR(err); |
357 | } |
358 | s->s_type = type; |
359 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); |
360 | list_add_tail(&s->s_list, &super_blocks); |
361 | list_add(&s->s_instances, &type->fs_supers); |
362 | spin_unlock(&sb_lock); |
363 | get_filesystem(type); |
364 | return s; |
365 | } |
366 | |
367 | EXPORT_SYMBOL(sget); |
368 | |
369 | void drop_super(struct super_block *sb) |
370 | { |
371 | up_read(&sb->s_umount); |
372 | put_super(sb); |
373 | } |
374 | |
375 | EXPORT_SYMBOL(drop_super); |
376 | |
377 | /** |
378 | * sync_supers - helper for periodic superblock writeback |
379 | * |
380 | * Call the write_super method if present on all dirty superblocks in |
381 | * the system. This is for the periodic writeback used by most older |
382 | * filesystems. For data integrity superblock writeback use |
383 | * sync_filesystems() instead. |
384 | * |
385 | * Note: check the dirty flag before waiting, so we don't |
386 | * hold up the sync while mounting a device. (The newly |
387 | * mounted device won't need syncing.) |
388 | */ |
389 | void sync_supers(void) |
390 | { |
391 | struct super_block *sb, *p = NULL; |
392 | |
393 | spin_lock(&sb_lock); |
394 | list_for_each_entry(sb, &super_blocks, s_list) { |
395 | if (list_empty(&sb->s_instances)) |
396 | continue; |
397 | if (sb->s_op->write_super && sb->s_dirt) { |
398 | sb->s_count++; |
399 | spin_unlock(&sb_lock); |
400 | |
401 | down_read(&sb->s_umount); |
402 | if (sb->s_root && sb->s_dirt) |
403 | sb->s_op->write_super(sb); |
404 | up_read(&sb->s_umount); |
405 | |
406 | spin_lock(&sb_lock); |
407 | if (p) |
408 | __put_super(p); |
409 | p = sb; |
410 | } |
411 | } |
412 | if (p) |
413 | __put_super(p); |
414 | spin_unlock(&sb_lock); |
415 | } |
416 | |
417 | /** |
418 | * iterate_supers - call function for all active superblocks |
419 | * @f: function to call |
420 | * @arg: argument to pass to it |
421 | * |
422 | * Scans the superblock list and calls given function, passing it |
423 | * locked superblock and given argument. |
424 | */ |
425 | void iterate_supers(void (*f)(struct super_block *, void *), void *arg) |
426 | { |
427 | struct super_block *sb, *p = NULL; |
428 | |
429 | spin_lock(&sb_lock); |
430 | list_for_each_entry(sb, &super_blocks, s_list) { |
431 | if (list_empty(&sb->s_instances)) |
432 | continue; |
433 | sb->s_count++; |
434 | spin_unlock(&sb_lock); |
435 | |
436 | down_read(&sb->s_umount); |
437 | if (sb->s_root) |
438 | f(sb, arg); |
439 | up_read(&sb->s_umount); |
440 | |
441 | spin_lock(&sb_lock); |
442 | if (p) |
443 | __put_super(p); |
444 | p = sb; |
445 | } |
446 | if (p) |
447 | __put_super(p); |
448 | spin_unlock(&sb_lock); |
449 | } |
450 | |
451 | /** |
452 | * get_super - get the superblock of a device |
453 | * @bdev: device to get the superblock for |
454 | * |
455 | * Scans the superblock list and finds the superblock of the file system |
456 | * mounted on the device given. %NULL is returned if no match is found. |
457 | */ |
458 | |
459 | struct super_block *get_super(struct block_device *bdev) |
460 | { |
461 | struct super_block *sb; |
462 | |
463 | if (!bdev) |
464 | return NULL; |
465 | |
466 | spin_lock(&sb_lock); |
467 | rescan: |
468 | list_for_each_entry(sb, &super_blocks, s_list) { |
469 | if (list_empty(&sb->s_instances)) |
470 | continue; |
471 | if (sb->s_bdev == bdev) { |
472 | sb->s_count++; |
473 | spin_unlock(&sb_lock); |
474 | down_read(&sb->s_umount); |
475 | /* still alive? */ |
476 | if (sb->s_root) |
477 | return sb; |
478 | up_read(&sb->s_umount); |
479 | /* nope, got unmounted */ |
480 | spin_lock(&sb_lock); |
481 | __put_super(sb); |
482 | goto rescan; |
483 | } |
484 | } |
485 | spin_unlock(&sb_lock); |
486 | return NULL; |
487 | } |
488 | |
489 | EXPORT_SYMBOL(get_super); |
490 | |
491 | /** |
492 | * get_active_super - get an active reference to the superblock of a device |
493 | * @bdev: device to get the superblock for |
494 | * |
495 | * Scans the superblock list and finds the superblock of the file system |
496 | * mounted on the device given. Returns the superblock with an active |
497 | * reference or %NULL if none was found. |
498 | */ |
499 | struct super_block *get_active_super(struct block_device *bdev) |
500 | { |
501 | struct super_block *sb; |
502 | |
503 | if (!bdev) |
504 | return NULL; |
505 | |
506 | restart: |
507 | spin_lock(&sb_lock); |
508 | list_for_each_entry(sb, &super_blocks, s_list) { |
509 | if (list_empty(&sb->s_instances)) |
510 | continue; |
511 | if (sb->s_bdev == bdev) { |
512 | if (grab_super(sb)) /* drops sb_lock */ |
513 | return sb; |
514 | else |
515 | goto restart; |
516 | } |
517 | } |
518 | spin_unlock(&sb_lock); |
519 | return NULL; |
520 | } |
521 | |
522 | struct super_block *user_get_super(dev_t dev) |
523 | { |
524 | struct super_block *sb; |
525 | |
526 | spin_lock(&sb_lock); |
527 | rescan: |
528 | list_for_each_entry(sb, &super_blocks, s_list) { |
529 | if (list_empty(&sb->s_instances)) |
530 | continue; |
531 | if (sb->s_dev == dev) { |
532 | sb->s_count++; |
533 | spin_unlock(&sb_lock); |
534 | down_read(&sb->s_umount); |
535 | /* still alive? */ |
536 | if (sb->s_root) |
537 | return sb; |
538 | up_read(&sb->s_umount); |
539 | /* nope, got unmounted */ |
540 | spin_lock(&sb_lock); |
541 | __put_super(sb); |
542 | goto rescan; |
543 | } |
544 | } |
545 | spin_unlock(&sb_lock); |
546 | return NULL; |
547 | } |
548 | |
549 | /** |
550 | * do_remount_sb - asks filesystem to change mount options. |
551 | * @sb: superblock in question |
552 | * @flags: numeric part of options |
553 | * @data: the rest of options |
554 | * @force: whether or not to force the change |
555 | * |
556 | * Alters the mount options of a mounted file system. |
557 | */ |
558 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) |
559 | { |
560 | int retval; |
561 | int remount_ro; |
562 | |
563 | if (sb->s_frozen != SB_UNFROZEN) |
564 | return -EBUSY; |
565 | |
566 | #ifdef CONFIG_BLOCK |
567 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
568 | return -EACCES; |
569 | #endif |
570 | |
571 | if (flags & MS_RDONLY) |
572 | acct_auto_close(sb); |
573 | shrink_dcache_sb(sb); |
574 | sync_filesystem(sb); |
575 | |
576 | remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY); |
577 | |
578 | /* If we are remounting RDONLY and current sb is read/write, |
579 | make sure there are no rw files opened */ |
580 | if (remount_ro) { |
581 | if (force) |
582 | mark_files_ro(sb); |
583 | else if (!fs_may_remount_ro(sb)) |
584 | return -EBUSY; |
585 | } |
586 | |
587 | if (sb->s_op->remount_fs) { |
588 | retval = sb->s_op->remount_fs(sb, &flags, data); |
589 | if (retval) |
590 | return retval; |
591 | } |
592 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); |
593 | |
594 | /* |
595 | * Some filesystems modify their metadata via some other path than the |
596 | * bdev buffer cache (eg. use a private mapping, or directories in |
597 | * pagecache, etc). Also file data modifications go via their own |
598 | * mappings. So If we try to mount readonly then copy the filesystem |
599 | * from bdev, we could get stale data, so invalidate it to give a best |
600 | * effort at coherency. |
601 | */ |
602 | if (remount_ro && sb->s_bdev) |
603 | invalidate_bdev(sb->s_bdev); |
604 | return 0; |
605 | } |
606 | |
607 | static void do_emergency_remount(struct work_struct *work) |
608 | { |
609 | struct super_block *sb, *p = NULL; |
610 | |
611 | spin_lock(&sb_lock); |
612 | list_for_each_entry(sb, &super_blocks, s_list) { |
613 | if (list_empty(&sb->s_instances)) |
614 | continue; |
615 | sb->s_count++; |
616 | spin_unlock(&sb_lock); |
617 | down_write(&sb->s_umount); |
618 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
619 | /* |
620 | * What lock protects sb->s_flags?? |
621 | */ |
622 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
623 | } |
624 | up_write(&sb->s_umount); |
625 | spin_lock(&sb_lock); |
626 | if (p) |
627 | __put_super(p); |
628 | p = sb; |
629 | } |
630 | if (p) |
631 | __put_super(p); |
632 | spin_unlock(&sb_lock); |
633 | kfree(work); |
634 | printk("Emergency Remount complete\n"); |
635 | } |
636 | |
637 | void emergency_remount(void) |
638 | { |
639 | struct work_struct *work; |
640 | |
641 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
642 | if (work) { |
643 | INIT_WORK(work, do_emergency_remount); |
644 | schedule_work(work); |
645 | } |
646 | } |
647 | |
648 | /* |
649 | * Unnamed block devices are dummy devices used by virtual |
650 | * filesystems which don't use real block-devices. -- jrs |
651 | */ |
652 | |
653 | static DEFINE_IDA(unnamed_dev_ida); |
654 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
655 | static int unnamed_dev_start = 0; /* don't bother trying below it */ |
656 | |
657 | int set_anon_super(struct super_block *s, void *data) |
658 | { |
659 | int dev; |
660 | int error; |
661 | |
662 | retry: |
663 | if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) |
664 | return -ENOMEM; |
665 | spin_lock(&unnamed_dev_lock); |
666 | error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); |
667 | if (!error) |
668 | unnamed_dev_start = dev + 1; |
669 | spin_unlock(&unnamed_dev_lock); |
670 | if (error == -EAGAIN) |
671 | /* We raced and lost with another CPU. */ |
672 | goto retry; |
673 | else if (error) |
674 | return -EAGAIN; |
675 | |
676 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { |
677 | spin_lock(&unnamed_dev_lock); |
678 | ida_remove(&unnamed_dev_ida, dev); |
679 | if (unnamed_dev_start > dev) |
680 | unnamed_dev_start = dev; |
681 | spin_unlock(&unnamed_dev_lock); |
682 | return -EMFILE; |
683 | } |
684 | s->s_dev = MKDEV(0, dev & MINORMASK); |
685 | s->s_bdi = &noop_backing_dev_info; |
686 | return 0; |
687 | } |
688 | |
689 | EXPORT_SYMBOL(set_anon_super); |
690 | |
691 | void kill_anon_super(struct super_block *sb) |
692 | { |
693 | int slot = MINOR(sb->s_dev); |
694 | |
695 | generic_shutdown_super(sb); |
696 | spin_lock(&unnamed_dev_lock); |
697 | ida_remove(&unnamed_dev_ida, slot); |
698 | if (slot < unnamed_dev_start) |
699 | unnamed_dev_start = slot; |
700 | spin_unlock(&unnamed_dev_lock); |
701 | } |
702 | |
703 | EXPORT_SYMBOL(kill_anon_super); |
704 | |
705 | void kill_litter_super(struct super_block *sb) |
706 | { |
707 | if (sb->s_root) |
708 | d_genocide(sb->s_root); |
709 | kill_anon_super(sb); |
710 | } |
711 | |
712 | EXPORT_SYMBOL(kill_litter_super); |
713 | |
714 | static int ns_test_super(struct super_block *sb, void *data) |
715 | { |
716 | return sb->s_fs_info == data; |
717 | } |
718 | |
719 | static int ns_set_super(struct super_block *sb, void *data) |
720 | { |
721 | sb->s_fs_info = data; |
722 | return set_anon_super(sb, NULL); |
723 | } |
724 | |
725 | struct dentry *mount_ns(struct file_system_type *fs_type, int flags, |
726 | void *data, int (*fill_super)(struct super_block *, void *, int)) |
727 | { |
728 | struct super_block *sb; |
729 | |
730 | sb = sget(fs_type, ns_test_super, ns_set_super, data); |
731 | if (IS_ERR(sb)) |
732 | return ERR_CAST(sb); |
733 | |
734 | if (!sb->s_root) { |
735 | int err; |
736 | sb->s_flags = flags; |
737 | err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); |
738 | if (err) { |
739 | deactivate_locked_super(sb); |
740 | return ERR_PTR(err); |
741 | } |
742 | |
743 | sb->s_flags |= MS_ACTIVE; |
744 | } |
745 | |
746 | return dget(sb->s_root); |
747 | } |
748 | |
749 | EXPORT_SYMBOL(mount_ns); |
750 | |
751 | #ifdef CONFIG_BLOCK |
752 | static int set_bdev_super(struct super_block *s, void *data) |
753 | { |
754 | s->s_bdev = data; |
755 | s->s_dev = s->s_bdev->bd_dev; |
756 | |
757 | /* |
758 | * We set the bdi here to the queue backing, file systems can |
759 | * overwrite this in ->fill_super() |
760 | */ |
761 | s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info; |
762 | return 0; |
763 | } |
764 | |
765 | static int test_bdev_super(struct super_block *s, void *data) |
766 | { |
767 | return (void *)s->s_bdev == data; |
768 | } |
769 | |
770 | struct dentry *mount_bdev(struct file_system_type *fs_type, |
771 | int flags, const char *dev_name, void *data, |
772 | int (*fill_super)(struct super_block *, void *, int)) |
773 | { |
774 | struct block_device *bdev; |
775 | struct super_block *s; |
776 | fmode_t mode = FMODE_READ | FMODE_EXCL; |
777 | int error = 0; |
778 | |
779 | if (!(flags & MS_RDONLY)) |
780 | mode |= FMODE_WRITE; |
781 | |
782 | bdev = blkdev_get_by_path(dev_name, mode, fs_type); |
783 | if (IS_ERR(bdev)) |
784 | return ERR_CAST(bdev); |
785 | |
786 | /* |
787 | * once the super is inserted into the list by sget, s_umount |
788 | * will protect the lockfs code from trying to start a snapshot |
789 | * while we are mounting |
790 | */ |
791 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
792 | if (bdev->bd_fsfreeze_count > 0) { |
793 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
794 | error = -EBUSY; |
795 | goto error_bdev; |
796 | } |
797 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
798 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
799 | if (IS_ERR(s)) |
800 | goto error_s; |
801 | |
802 | if (s->s_root) { |
803 | if ((flags ^ s->s_flags) & MS_RDONLY) { |
804 | deactivate_locked_super(s); |
805 | error = -EBUSY; |
806 | goto error_bdev; |
807 | } |
808 | |
809 | /* |
810 | * s_umount nests inside bd_mutex during |
811 | * __invalidate_device(). blkdev_put() acquires |
812 | * bd_mutex and can't be called under s_umount. Drop |
813 | * s_umount temporarily. This is safe as we're |
814 | * holding an active reference. |
815 | */ |
816 | up_write(&s->s_umount); |
817 | blkdev_put(bdev, mode); |
818 | down_write(&s->s_umount); |
819 | } else { |
820 | char b[BDEVNAME_SIZE]; |
821 | |
822 | s->s_flags = flags; |
823 | s->s_mode = mode; |
824 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
825 | sb_set_blocksize(s, block_size(bdev)); |
826 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
827 | if (error) { |
828 | deactivate_locked_super(s); |
829 | goto error; |
830 | } |
831 | |
832 | s->s_flags |= MS_ACTIVE; |
833 | bdev->bd_super = s; |
834 | } |
835 | |
836 | return dget(s->s_root); |
837 | |
838 | error_s: |
839 | error = PTR_ERR(s); |
840 | error_bdev: |
841 | blkdev_put(bdev, mode); |
842 | error: |
843 | return ERR_PTR(error); |
844 | } |
845 | EXPORT_SYMBOL(mount_bdev); |
846 | |
847 | void kill_block_super(struct super_block *sb) |
848 | { |
849 | struct block_device *bdev = sb->s_bdev; |
850 | fmode_t mode = sb->s_mode; |
851 | |
852 | bdev->bd_super = NULL; |
853 | generic_shutdown_super(sb); |
854 | sync_blockdev(bdev); |
855 | WARN_ON_ONCE(!(mode & FMODE_EXCL)); |
856 | blkdev_put(bdev, mode | FMODE_EXCL); |
857 | } |
858 | |
859 | EXPORT_SYMBOL(kill_block_super); |
860 | #endif |
861 | |
862 | struct dentry *mount_nodev(struct file_system_type *fs_type, |
863 | int flags, void *data, |
864 | int (*fill_super)(struct super_block *, void *, int)) |
865 | { |
866 | int error; |
867 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); |
868 | |
869 | if (IS_ERR(s)) |
870 | return ERR_CAST(s); |
871 | |
872 | s->s_flags = flags; |
873 | |
874 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
875 | if (error) { |
876 | deactivate_locked_super(s); |
877 | return ERR_PTR(error); |
878 | } |
879 | s->s_flags |= MS_ACTIVE; |
880 | return dget(s->s_root); |
881 | } |
882 | EXPORT_SYMBOL(mount_nodev); |
883 | |
884 | static int compare_single(struct super_block *s, void *p) |
885 | { |
886 | return 1; |
887 | } |
888 | |
889 | struct dentry *mount_single(struct file_system_type *fs_type, |
890 | int flags, void *data, |
891 | int (*fill_super)(struct super_block *, void *, int)) |
892 | { |
893 | struct super_block *s; |
894 | int error; |
895 | |
896 | s = sget(fs_type, compare_single, set_anon_super, NULL); |
897 | if (IS_ERR(s)) |
898 | return ERR_CAST(s); |
899 | if (!s->s_root) { |
900 | s->s_flags = flags; |
901 | error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); |
902 | if (error) { |
903 | deactivate_locked_super(s); |
904 | return ERR_PTR(error); |
905 | } |
906 | s->s_flags |= MS_ACTIVE; |
907 | } else { |
908 | do_remount_sb(s, flags, data, 0); |
909 | } |
910 | return dget(s->s_root); |
911 | } |
912 | EXPORT_SYMBOL(mount_single); |
913 | |
914 | struct dentry * |
915 | mount_fs(struct file_system_type *type, int flags, const char *name, void *data) |
916 | { |
917 | struct dentry *root; |
918 | struct super_block *sb; |
919 | char *secdata = NULL; |
920 | int error = -ENOMEM; |
921 | |
922 | if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { |
923 | secdata = alloc_secdata(); |
924 | if (!secdata) |
925 | goto out; |
926 | |
927 | error = security_sb_copy_data(data, secdata); |
928 | if (error) |
929 | goto out_free_secdata; |
930 | } |
931 | |
932 | root = type->mount(type, flags, name, data); |
933 | if (IS_ERR(root)) { |
934 | error = PTR_ERR(root); |
935 | goto out_free_secdata; |
936 | } |
937 | sb = root->d_sb; |
938 | BUG_ON(!sb); |
939 | WARN_ON(!sb->s_bdi); |
940 | WARN_ON(sb->s_bdi == &default_backing_dev_info); |
941 | sb->s_flags |= MS_BORN; |
942 | |
943 | error = security_sb_kern_mount(sb, flags, secdata); |
944 | if (error) |
945 | goto out_sb; |
946 | |
947 | /* |
948 | * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE |
949 | * but s_maxbytes was an unsigned long long for many releases. Throw |
950 | * this warning for a little while to try and catch filesystems that |
951 | * violate this rule. This warning should be either removed or |
952 | * converted to a BUG() in 2.6.34. |
953 | */ |
954 | WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " |
955 | "negative value (%lld)\n", type->name, sb->s_maxbytes); |
956 | |
957 | up_write(&sb->s_umount); |
958 | free_secdata(secdata); |
959 | return root; |
960 | out_sb: |
961 | dput(root); |
962 | deactivate_locked_super(sb); |
963 | out_free_secdata: |
964 | free_secdata(secdata); |
965 | out: |
966 | return ERR_PTR(error); |
967 | } |
968 | |
969 | /** |
970 | * freeze_super - lock the filesystem and force it into a consistent state |
971 | * @sb: the super to lock |
972 | * |
973 | * Syncs the super to make sure the filesystem is consistent and calls the fs's |
974 | * freeze_fs. Subsequent calls to this without first thawing the fs will return |
975 | * -EBUSY. |
976 | */ |
977 | int freeze_super(struct super_block *sb) |
978 | { |
979 | int ret; |
980 | |
981 | atomic_inc(&sb->s_active); |
982 | down_write(&sb->s_umount); |
983 | if (sb->s_frozen) { |
984 | deactivate_locked_super(sb); |
985 | return -EBUSY; |
986 | } |
987 | |
988 | if (sb->s_flags & MS_RDONLY) { |
989 | sb->s_frozen = SB_FREEZE_TRANS; |
990 | smp_wmb(); |
991 | up_write(&sb->s_umount); |
992 | return 0; |
993 | } |
994 | |
995 | sb->s_frozen = SB_FREEZE_WRITE; |
996 | smp_wmb(); |
997 | |
998 | sync_filesystem(sb); |
999 | |
1000 | sb->s_frozen = SB_FREEZE_TRANS; |
1001 | smp_wmb(); |
1002 | |
1003 | sync_blockdev(sb->s_bdev); |
1004 | if (sb->s_op->freeze_fs) { |
1005 | ret = sb->s_op->freeze_fs(sb); |
1006 | if (ret) { |
1007 | printk(KERN_ERR |
1008 | "VFS:Filesystem freeze failed\n"); |
1009 | sb->s_frozen = SB_UNFROZEN; |
1010 | deactivate_locked_super(sb); |
1011 | return ret; |
1012 | } |
1013 | } |
1014 | up_write(&sb->s_umount); |
1015 | return 0; |
1016 | } |
1017 | EXPORT_SYMBOL(freeze_super); |
1018 | |
1019 | /** |
1020 | * thaw_super -- unlock filesystem |
1021 | * @sb: the super to thaw |
1022 | * |
1023 | * Unlocks the filesystem and marks it writeable again after freeze_super(). |
1024 | */ |
1025 | int thaw_super(struct super_block *sb) |
1026 | { |
1027 | int error; |
1028 | |
1029 | down_write(&sb->s_umount); |
1030 | if (sb->s_frozen == SB_UNFROZEN) { |
1031 | up_write(&sb->s_umount); |
1032 | return -EINVAL; |
1033 | } |
1034 | |
1035 | if (sb->s_flags & MS_RDONLY) |
1036 | goto out; |
1037 | |
1038 | if (sb->s_op->unfreeze_fs) { |
1039 | error = sb->s_op->unfreeze_fs(sb); |
1040 | if (error) { |
1041 | printk(KERN_ERR |
1042 | "VFS:Filesystem thaw failed\n"); |
1043 | sb->s_frozen = SB_FREEZE_TRANS; |
1044 | up_write(&sb->s_umount); |
1045 | return error; |
1046 | } |
1047 | } |
1048 | |
1049 | out: |
1050 | sb->s_frozen = SB_UNFROZEN; |
1051 | smp_wmb(); |
1052 | wake_up(&sb->s_wait_unfrozen); |
1053 | deactivate_locked_super(sb); |
1054 | |
1055 | return 0; |
1056 | } |
1057 | EXPORT_SYMBOL(thaw_super); |
1058 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9