Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/fs/super.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 20383 byte(s)
Tag kernel26-2.6.12-alx-r9
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/config.h> |
24 | #include <linux/module.h> |
25 | #include <linux/slab.h> |
26 | #include <linux/init.h> |
27 | #include <linux/smp_lock.h> |
28 | #include <linux/acct.h> |
29 | #include <linux/blkdev.h> |
30 | #include <linux/quotaops.h> |
31 | #include <linux/namei.h> |
32 | #include <linux/buffer_head.h> /* for fsync_super() */ |
33 | #include <linux/mount.h> |
34 | #include <linux/security.h> |
35 | #include <linux/syscalls.h> |
36 | #include <linux/vfs.h> |
37 | #include <linux/writeback.h> /* for the emergency remount stuff */ |
38 | #include <linux/idr.h> |
39 | #include <linux/kobject.h> |
40 | #include <asm/uaccess.h> |
41 | |
42 | |
43 | void get_filesystem(struct file_system_type *fs); |
44 | void put_filesystem(struct file_system_type *fs); |
45 | struct file_system_type *get_fs_type(const char *name); |
46 | |
47 | LIST_HEAD(super_blocks); |
48 | DEFINE_SPINLOCK(sb_lock); |
49 | |
50 | /** |
51 | * alloc_super - create new superblock |
52 | * |
53 | * Allocates and initializes a new &struct super_block. alloc_super() |
54 | * returns a pointer new superblock or %NULL if allocation had failed. |
55 | */ |
56 | static struct super_block *alloc_super(void) |
57 | { |
58 | struct super_block *s = kmalloc(sizeof(struct super_block), GFP_USER); |
59 | static struct super_operations default_op; |
60 | |
61 | if (s) { |
62 | memset(s, 0, sizeof(struct super_block)); |
63 | if (security_sb_alloc(s)) { |
64 | kfree(s); |
65 | s = NULL; |
66 | goto out; |
67 | } |
68 | INIT_LIST_HEAD(&s->s_dirty); |
69 | INIT_LIST_HEAD(&s->s_io); |
70 | INIT_LIST_HEAD(&s->s_files); |
71 | INIT_LIST_HEAD(&s->s_instances); |
72 | INIT_HLIST_HEAD(&s->s_anon); |
73 | INIT_LIST_HEAD(&s->s_inodes); |
74 | init_rwsem(&s->s_umount); |
75 | sema_init(&s->s_lock, 1); |
76 | down_write(&s->s_umount); |
77 | s->s_count = S_BIAS; |
78 | atomic_set(&s->s_active, 1); |
79 | sema_init(&s->s_vfs_rename_sem,1); |
80 | sema_init(&s->s_dquot.dqio_sem, 1); |
81 | sema_init(&s->s_dquot.dqonoff_sem, 1); |
82 | init_rwsem(&s->s_dquot.dqptr_sem); |
83 | init_waitqueue_head(&s->s_wait_unfrozen); |
84 | s->s_maxbytes = MAX_NON_LFS; |
85 | s->dq_op = sb_dquot_ops; |
86 | s->s_qcop = sb_quotactl_ops; |
87 | s->s_op = &default_op; |
88 | s->s_time_gran = 1000000000; |
89 | } |
90 | out: |
91 | return s; |
92 | } |
93 | |
94 | /** |
95 | * destroy_super - frees a superblock |
96 | * @s: superblock to free |
97 | * |
98 | * Frees a superblock. |
99 | */ |
100 | static inline void destroy_super(struct super_block *s) |
101 | { |
102 | security_sb_free(s); |
103 | kfree(s); |
104 | } |
105 | |
106 | /* Superblock refcounting */ |
107 | |
108 | /* |
109 | * Drop a superblock's refcount. Returns non-zero if the superblock was |
110 | * destroyed. The caller must hold sb_lock. |
111 | */ |
112 | int __put_super(struct super_block *sb) |
113 | { |
114 | int ret = 0; |
115 | |
116 | if (!--sb->s_count) { |
117 | destroy_super(sb); |
118 | ret = 1; |
119 | } |
120 | return ret; |
121 | } |
122 | |
123 | /* |
124 | * Drop a superblock's refcount. |
125 | * Returns non-zero if the superblock is about to be destroyed and |
126 | * at least is already removed from super_blocks list, so if we are |
127 | * making a loop through super blocks then we need to restart. |
128 | * The caller must hold sb_lock. |
129 | */ |
130 | int __put_super_and_need_restart(struct super_block *sb) |
131 | { |
132 | /* check for race with generic_shutdown_super() */ |
133 | if (list_empty(&sb->s_list)) { |
134 | /* super block is removed, need to restart... */ |
135 | __put_super(sb); |
136 | return 1; |
137 | } |
138 | /* can't be the last, since s_list is still in use */ |
139 | sb->s_count--; |
140 | BUG_ON(sb->s_count == 0); |
141 | return 0; |
142 | } |
143 | |
144 | /** |
145 | * put_super - drop a temporary reference to superblock |
146 | * @sb: superblock in question |
147 | * |
148 | * Drops a temporary reference, frees superblock if there's no |
149 | * references left. |
150 | */ |
151 | static void put_super(struct super_block *sb) |
152 | { |
153 | spin_lock(&sb_lock); |
154 | __put_super(sb); |
155 | spin_unlock(&sb_lock); |
156 | } |
157 | |
158 | |
159 | /** |
160 | * deactivate_super - drop an active reference to superblock |
161 | * @s: superblock to deactivate |
162 | * |
163 | * Drops an active reference to superblock, acquiring a temprory one if |
164 | * there is no active references left. In that case we lock superblock, |
165 | * tell fs driver to shut it down and drop the temporary reference we |
166 | * had just acquired. |
167 | */ |
168 | void deactivate_super(struct super_block *s) |
169 | { |
170 | struct file_system_type *fs = s->s_type; |
171 | if (atomic_dec_and_lock(&s->s_active, &sb_lock)) { |
172 | s->s_count -= S_BIAS-1; |
173 | spin_unlock(&sb_lock); |
174 | down_write(&s->s_umount); |
175 | fs->kill_sb(s); |
176 | put_filesystem(fs); |
177 | put_super(s); |
178 | } |
179 | } |
180 | |
181 | EXPORT_SYMBOL(deactivate_super); |
182 | |
183 | /** |
184 | * grab_super - acquire an active reference |
185 | * @s: reference we are trying to make active |
186 | * |
187 | * Tries to acquire an active reference. grab_super() is used when we |
188 | * had just found a superblock in super_blocks or fs_type->fs_supers |
189 | * and want to turn it into a full-blown active reference. grab_super() |
190 | * is called with sb_lock held and drops it. Returns 1 in case of |
191 | * success, 0 if we had failed (superblock contents was already dead or |
192 | * dying when grab_super() had been called). |
193 | */ |
194 | static int grab_super(struct super_block *s) |
195 | { |
196 | s->s_count++; |
197 | spin_unlock(&sb_lock); |
198 | down_write(&s->s_umount); |
199 | if (s->s_root) { |
200 | spin_lock(&sb_lock); |
201 | if (s->s_count > S_BIAS) { |
202 | atomic_inc(&s->s_active); |
203 | s->s_count--; |
204 | spin_unlock(&sb_lock); |
205 | return 1; |
206 | } |
207 | spin_unlock(&sb_lock); |
208 | } |
209 | up_write(&s->s_umount); |
210 | put_super(s); |
211 | yield(); |
212 | return 0; |
213 | } |
214 | |
215 | /** |
216 | * generic_shutdown_super - common helper for ->kill_sb() |
217 | * @sb: superblock to kill |
218 | * |
219 | * generic_shutdown_super() does all fs-independent work on superblock |
220 | * shutdown. Typical ->kill_sb() should pick all fs-specific objects |
221 | * that need destruction out of superblock, call generic_shutdown_super() |
222 | * and release aforementioned objects. Note: dentries and inodes _are_ |
223 | * taken care of and do not need specific handling. |
224 | */ |
225 | void generic_shutdown_super(struct super_block *sb) |
226 | { |
227 | struct dentry *root = sb->s_root; |
228 | struct super_operations *sop = sb->s_op; |
229 | |
230 | if (root) { |
231 | sb->s_root = NULL; |
232 | shrink_dcache_parent(root); |
233 | shrink_dcache_anon(&sb->s_anon); |
234 | dput(root); |
235 | fsync_super(sb); |
236 | lock_super(sb); |
237 | sb->s_flags &= ~MS_ACTIVE; |
238 | /* bad name - it should be evict_inodes() */ |
239 | invalidate_inodes(sb); |
240 | lock_kernel(); |
241 | |
242 | if (sop->write_super && sb->s_dirt) |
243 | sop->write_super(sb); |
244 | if (sop->put_super) |
245 | sop->put_super(sb); |
246 | |
247 | /* Forget any remaining inodes */ |
248 | if (invalidate_inodes(sb)) { |
249 | printk("VFS: Busy inodes after unmount. " |
250 | "Self-destruct in 5 seconds. Have a nice day...\n"); |
251 | } |
252 | |
253 | unlock_kernel(); |
254 | unlock_super(sb); |
255 | } |
256 | spin_lock(&sb_lock); |
257 | /* should be initialized for __put_super_and_need_restart() */ |
258 | list_del_init(&sb->s_list); |
259 | list_del(&sb->s_instances); |
260 | spin_unlock(&sb_lock); |
261 | up_write(&sb->s_umount); |
262 | } |
263 | |
264 | EXPORT_SYMBOL(generic_shutdown_super); |
265 | |
266 | /** |
267 | * sget - find or create a superblock |
268 | * @type: filesystem type superblock should belong to |
269 | * @test: comparison callback |
270 | * @set: setup callback |
271 | * @data: argument to each of them |
272 | */ |
273 | struct super_block *sget(struct file_system_type *type, |
274 | int (*test)(struct super_block *,void *), |
275 | int (*set)(struct super_block *,void *), |
276 | void *data) |
277 | { |
278 | struct super_block *s = NULL; |
279 | struct list_head *p; |
280 | int err; |
281 | |
282 | retry: |
283 | spin_lock(&sb_lock); |
284 | if (test) list_for_each(p, &type->fs_supers) { |
285 | struct super_block *old; |
286 | old = list_entry(p, struct super_block, s_instances); |
287 | if (!test(old, data)) |
288 | continue; |
289 | if (!grab_super(old)) |
290 | goto retry; |
291 | if (s) |
292 | destroy_super(s); |
293 | return old; |
294 | } |
295 | if (!s) { |
296 | spin_unlock(&sb_lock); |
297 | s = alloc_super(); |
298 | if (!s) |
299 | return ERR_PTR(-ENOMEM); |
300 | goto retry; |
301 | } |
302 | |
303 | err = set(s, data); |
304 | if (err) { |
305 | spin_unlock(&sb_lock); |
306 | destroy_super(s); |
307 | return ERR_PTR(err); |
308 | } |
309 | s->s_type = type; |
310 | strlcpy(s->s_id, type->name, sizeof(s->s_id)); |
311 | list_add_tail(&s->s_list, &super_blocks); |
312 | list_add(&s->s_instances, &type->fs_supers); |
313 | spin_unlock(&sb_lock); |
314 | get_filesystem(type); |
315 | return s; |
316 | } |
317 | |
318 | EXPORT_SYMBOL(sget); |
319 | |
320 | void drop_super(struct super_block *sb) |
321 | { |
322 | up_read(&sb->s_umount); |
323 | put_super(sb); |
324 | } |
325 | |
326 | EXPORT_SYMBOL(drop_super); |
327 | |
328 | static inline void write_super(struct super_block *sb) |
329 | { |
330 | lock_super(sb); |
331 | if (sb->s_root && sb->s_dirt) |
332 | if (sb->s_op->write_super) |
333 | sb->s_op->write_super(sb); |
334 | unlock_super(sb); |
335 | } |
336 | |
337 | /* |
338 | * Note: check the dirty flag before waiting, so we don't |
339 | * hold up the sync while mounting a device. (The newly |
340 | * mounted device won't need syncing.) |
341 | */ |
342 | void sync_supers(void) |
343 | { |
344 | struct super_block * sb; |
345 | restart: |
346 | spin_lock(&sb_lock); |
347 | sb = sb_entry(super_blocks.next); |
348 | while (sb != sb_entry(&super_blocks)) |
349 | if (sb->s_dirt) { |
350 | sb->s_count++; |
351 | spin_unlock(&sb_lock); |
352 | down_read(&sb->s_umount); |
353 | write_super(sb); |
354 | drop_super(sb); |
355 | goto restart; |
356 | } else |
357 | sb = sb_entry(sb->s_list.next); |
358 | spin_unlock(&sb_lock); |
359 | } |
360 | |
361 | /* |
362 | * Call the ->sync_fs super_op against all filesytems which are r/w and |
363 | * which implement it. |
364 | * |
365 | * This operation is careful to avoid the livelock which could easily happen |
366 | * if two or more filesystems are being continuously dirtied. s_need_sync_fs |
367 | * is used only here. We set it against all filesystems and then clear it as |
368 | * we sync them. So redirtied filesystems are skipped. |
369 | * |
370 | * But if process A is currently running sync_filesytems and then process B |
371 | * calls sync_filesystems as well, process B will set all the s_need_sync_fs |
372 | * flags again, which will cause process A to resync everything. Fix that with |
373 | * a local mutex. |
374 | * |
375 | * (Fabian) Avoid sync_fs with clean fs & wait mode 0 |
376 | */ |
377 | void sync_filesystems(int wait) |
378 | { |
379 | struct super_block *sb; |
380 | static DECLARE_MUTEX(mutex); |
381 | |
382 | down(&mutex); /* Could be down_interruptible */ |
383 | spin_lock(&sb_lock); |
384 | for (sb = sb_entry(super_blocks.next); sb != sb_entry(&super_blocks); |
385 | sb = sb_entry(sb->s_list.next)) { |
386 | if (!sb->s_op->sync_fs) |
387 | continue; |
388 | if (sb->s_flags & MS_RDONLY) |
389 | continue; |
390 | sb->s_need_sync_fs = 1; |
391 | } |
392 | spin_unlock(&sb_lock); |
393 | |
394 | restart: |
395 | spin_lock(&sb_lock); |
396 | for (sb = sb_entry(super_blocks.next); sb != sb_entry(&super_blocks); |
397 | sb = sb_entry(sb->s_list.next)) { |
398 | if (!sb->s_need_sync_fs) |
399 | continue; |
400 | sb->s_need_sync_fs = 0; |
401 | if (sb->s_flags & MS_RDONLY) |
402 | continue; /* hm. Was remounted r/o meanwhile */ |
403 | sb->s_count++; |
404 | spin_unlock(&sb_lock); |
405 | down_read(&sb->s_umount); |
406 | if (sb->s_root && (wait || sb->s_dirt)) |
407 | sb->s_op->sync_fs(sb, wait); |
408 | drop_super(sb); |
409 | goto restart; |
410 | } |
411 | spin_unlock(&sb_lock); |
412 | up(&mutex); |
413 | } |
414 | |
415 | /** |
416 | * get_super - get the superblock of a device |
417 | * @bdev: device to get the superblock for |
418 | * |
419 | * Scans the superblock list and finds the superblock of the file system |
420 | * mounted on the device given. %NULL is returned if no match is found. |
421 | */ |
422 | |
423 | struct super_block * get_super(struct block_device *bdev) |
424 | { |
425 | struct list_head *p; |
426 | if (!bdev) |
427 | return NULL; |
428 | rescan: |
429 | spin_lock(&sb_lock); |
430 | list_for_each(p, &super_blocks) { |
431 | struct super_block *s = sb_entry(p); |
432 | if (s->s_bdev == bdev) { |
433 | s->s_count++; |
434 | spin_unlock(&sb_lock); |
435 | down_read(&s->s_umount); |
436 | if (s->s_root) |
437 | return s; |
438 | drop_super(s); |
439 | goto rescan; |
440 | } |
441 | } |
442 | spin_unlock(&sb_lock); |
443 | return NULL; |
444 | } |
445 | |
446 | EXPORT_SYMBOL(get_super); |
447 | |
448 | struct super_block * user_get_super(dev_t dev) |
449 | { |
450 | struct list_head *p; |
451 | |
452 | rescan: |
453 | spin_lock(&sb_lock); |
454 | list_for_each(p, &super_blocks) { |
455 | struct super_block *s = sb_entry(p); |
456 | if (s->s_dev == dev) { |
457 | s->s_count++; |
458 | spin_unlock(&sb_lock); |
459 | down_read(&s->s_umount); |
460 | if (s->s_root) |
461 | return s; |
462 | drop_super(s); |
463 | goto rescan; |
464 | } |
465 | } |
466 | spin_unlock(&sb_lock); |
467 | return NULL; |
468 | } |
469 | |
470 | EXPORT_SYMBOL(user_get_super); |
471 | |
472 | asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf) |
473 | { |
474 | struct super_block *s; |
475 | struct ustat tmp; |
476 | struct kstatfs sbuf; |
477 | int err = -EINVAL; |
478 | |
479 | s = user_get_super(new_decode_dev(dev)); |
480 | if (s == NULL) |
481 | goto out; |
482 | err = vfs_statfs(s, &sbuf); |
483 | drop_super(s); |
484 | if (err) |
485 | goto out; |
486 | |
487 | memset(&tmp,0,sizeof(struct ustat)); |
488 | tmp.f_tfree = sbuf.f_bfree; |
489 | tmp.f_tinode = sbuf.f_ffree; |
490 | |
491 | err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; |
492 | out: |
493 | return err; |
494 | } |
495 | |
496 | /** |
497 | * mark_files_ro |
498 | * @sb: superblock in question |
499 | * |
500 | * All files are marked read/only. We don't care about pending |
501 | * delete files so this should be used in 'force' mode only |
502 | */ |
503 | |
504 | static void mark_files_ro(struct super_block *sb) |
505 | { |
506 | struct file *f; |
507 | |
508 | file_list_lock(); |
509 | list_for_each_entry(f, &sb->s_files, f_list) { |
510 | if (S_ISREG(f->f_dentry->d_inode->i_mode) && file_count(f)) |
511 | f->f_mode &= ~FMODE_WRITE; |
512 | } |
513 | file_list_unlock(); |
514 | } |
515 | |
516 | /** |
517 | * do_remount_sb - asks filesystem to change mount options. |
518 | * @sb: superblock in question |
519 | * @flags: numeric part of options |
520 | * @data: the rest of options |
521 | * @force: whether or not to force the change |
522 | * |
523 | * Alters the mount options of a mounted file system. |
524 | */ |
525 | int do_remount_sb(struct super_block *sb, int flags, void *data, int force) |
526 | { |
527 | int retval; |
528 | |
529 | if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev)) |
530 | return -EACCES; |
531 | if (flags & MS_RDONLY) |
532 | acct_auto_close(sb); |
533 | shrink_dcache_sb(sb); |
534 | fsync_super(sb); |
535 | |
536 | /* If we are remounting RDONLY and current sb is read/write, |
537 | make sure there are no rw files opened */ |
538 | if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) { |
539 | if (force) |
540 | mark_files_ro(sb); |
541 | else if (!fs_may_remount_ro(sb)) |
542 | return -EBUSY; |
543 | } |
544 | |
545 | if (sb->s_op->remount_fs) { |
546 | lock_super(sb); |
547 | retval = sb->s_op->remount_fs(sb, &flags, data); |
548 | unlock_super(sb); |
549 | if (retval) |
550 | return retval; |
551 | } |
552 | sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); |
553 | return 0; |
554 | } |
555 | |
556 | static void do_emergency_remount(unsigned long foo) |
557 | { |
558 | struct super_block *sb; |
559 | |
560 | spin_lock(&sb_lock); |
561 | list_for_each_entry(sb, &super_blocks, s_list) { |
562 | sb->s_count++; |
563 | spin_unlock(&sb_lock); |
564 | down_read(&sb->s_umount); |
565 | if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) { |
566 | /* |
567 | * ->remount_fs needs lock_kernel(). |
568 | * |
569 | * What lock protects sb->s_flags?? |
570 | */ |
571 | lock_kernel(); |
572 | do_remount_sb(sb, MS_RDONLY, NULL, 1); |
573 | unlock_kernel(); |
574 | } |
575 | drop_super(sb); |
576 | spin_lock(&sb_lock); |
577 | } |
578 | spin_unlock(&sb_lock); |
579 | printk("Emergency Remount complete\n"); |
580 | } |
581 | |
582 | void emergency_remount(void) |
583 | { |
584 | pdflush_operation(do_emergency_remount, 0); |
585 | } |
586 | |
587 | /* |
588 | * Unnamed block devices are dummy devices used by virtual |
589 | * filesystems which don't use real block-devices. -- jrs |
590 | */ |
591 | |
592 | static struct idr unnamed_dev_idr; |
593 | static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ |
594 | |
595 | int set_anon_super(struct super_block *s, void *data) |
596 | { |
597 | int dev; |
598 | int error; |
599 | |
600 | retry: |
601 | if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0) |
602 | return -ENOMEM; |
603 | spin_lock(&unnamed_dev_lock); |
604 | error = idr_get_new(&unnamed_dev_idr, NULL, &dev); |
605 | spin_unlock(&unnamed_dev_lock); |
606 | if (error == -EAGAIN) |
607 | /* We raced and lost with another CPU. */ |
608 | goto retry; |
609 | else if (error) |
610 | return -EAGAIN; |
611 | |
612 | if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) { |
613 | spin_lock(&unnamed_dev_lock); |
614 | idr_remove(&unnamed_dev_idr, dev); |
615 | spin_unlock(&unnamed_dev_lock); |
616 | return -EMFILE; |
617 | } |
618 | s->s_dev = MKDEV(0, dev & MINORMASK); |
619 | return 0; |
620 | } |
621 | |
622 | EXPORT_SYMBOL(set_anon_super); |
623 | |
624 | void kill_anon_super(struct super_block *sb) |
625 | { |
626 | int slot = MINOR(sb->s_dev); |
627 | |
628 | generic_shutdown_super(sb); |
629 | spin_lock(&unnamed_dev_lock); |
630 | idr_remove(&unnamed_dev_idr, slot); |
631 | spin_unlock(&unnamed_dev_lock); |
632 | } |
633 | |
634 | EXPORT_SYMBOL(kill_anon_super); |
635 | |
636 | void __init unnamed_dev_init(void) |
637 | { |
638 | idr_init(&unnamed_dev_idr); |
639 | } |
640 | |
641 | void kill_litter_super(struct super_block *sb) |
642 | { |
643 | if (sb->s_root) |
644 | d_genocide(sb->s_root); |
645 | kill_anon_super(sb); |
646 | } |
647 | |
648 | EXPORT_SYMBOL(kill_litter_super); |
649 | |
650 | static int set_bdev_super(struct super_block *s, void *data) |
651 | { |
652 | s->s_bdev = data; |
653 | s->s_dev = s->s_bdev->bd_dev; |
654 | return 0; |
655 | } |
656 | |
657 | static int test_bdev_super(struct super_block *s, void *data) |
658 | { |
659 | return (void *)s->s_bdev == data; |
660 | } |
661 | |
662 | static void bdev_uevent(struct block_device *bdev, enum kobject_action action) |
663 | { |
664 | if (bdev->bd_disk) { |
665 | if (bdev->bd_part) |
666 | kobject_uevent(&bdev->bd_part->kobj, action, NULL); |
667 | else |
668 | kobject_uevent(&bdev->bd_disk->kobj, action, NULL); |
669 | } |
670 | } |
671 | |
672 | struct super_block *get_sb_bdev(struct file_system_type *fs_type, |
673 | int flags, const char *dev_name, void *data, |
674 | int (*fill_super)(struct super_block *, void *, int)) |
675 | { |
676 | struct block_device *bdev; |
677 | struct super_block *s; |
678 | int error = 0; |
679 | |
680 | bdev = open_bdev_excl(dev_name, flags, fs_type); |
681 | if (IS_ERR(bdev)) |
682 | return (struct super_block *)bdev; |
683 | |
684 | /* |
685 | * once the super is inserted into the list by sget, s_umount |
686 | * will protect the lockfs code from trying to start a snapshot |
687 | * while we are mounting |
688 | */ |
689 | down(&bdev->bd_mount_sem); |
690 | s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); |
691 | up(&bdev->bd_mount_sem); |
692 | if (IS_ERR(s)) |
693 | goto out; |
694 | |
695 | if (s->s_root) { |
696 | if ((flags ^ s->s_flags) & MS_RDONLY) { |
697 | up_write(&s->s_umount); |
698 | deactivate_super(s); |
699 | s = ERR_PTR(-EBUSY); |
700 | } |
701 | goto out; |
702 | } else { |
703 | char b[BDEVNAME_SIZE]; |
704 | |
705 | s->s_flags = flags; |
706 | strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); |
707 | s->s_old_blocksize = block_size(bdev); |
708 | sb_set_blocksize(s, s->s_old_blocksize); |
709 | error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
710 | if (error) { |
711 | up_write(&s->s_umount); |
712 | deactivate_super(s); |
713 | s = ERR_PTR(error); |
714 | } else { |
715 | s->s_flags |= MS_ACTIVE; |
716 | bdev_uevent(bdev, KOBJ_MOUNT); |
717 | } |
718 | } |
719 | |
720 | return s; |
721 | |
722 | out: |
723 | close_bdev_excl(bdev); |
724 | return s; |
725 | } |
726 | |
727 | EXPORT_SYMBOL(get_sb_bdev); |
728 | |
729 | void kill_block_super(struct super_block *sb) |
730 | { |
731 | struct block_device *bdev = sb->s_bdev; |
732 | |
733 | bdev_uevent(bdev, KOBJ_UMOUNT); |
734 | generic_shutdown_super(sb); |
735 | sync_blockdev(bdev); |
736 | close_bdev_excl(bdev); |
737 | } |
738 | |
739 | EXPORT_SYMBOL(kill_block_super); |
740 | |
741 | struct super_block *get_sb_nodev(struct file_system_type *fs_type, |
742 | int flags, void *data, |
743 | int (*fill_super)(struct super_block *, void *, int)) |
744 | { |
745 | int error; |
746 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); |
747 | |
748 | if (IS_ERR(s)) |
749 | return s; |
750 | |
751 | s->s_flags = flags; |
752 | |
753 | error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
754 | if (error) { |
755 | up_write(&s->s_umount); |
756 | deactivate_super(s); |
757 | return ERR_PTR(error); |
758 | } |
759 | s->s_flags |= MS_ACTIVE; |
760 | return s; |
761 | } |
762 | |
763 | EXPORT_SYMBOL(get_sb_nodev); |
764 | |
765 | static int compare_single(struct super_block *s, void *p) |
766 | { |
767 | return 1; |
768 | } |
769 | |
770 | struct super_block *get_sb_single(struct file_system_type *fs_type, |
771 | int flags, void *data, |
772 | int (*fill_super)(struct super_block *, void *, int)) |
773 | { |
774 | struct super_block *s; |
775 | int error; |
776 | |
777 | s = sget(fs_type, compare_single, set_anon_super, NULL); |
778 | if (IS_ERR(s)) |
779 | return s; |
780 | if (!s->s_root) { |
781 | s->s_flags = flags; |
782 | error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
783 | if (error) { |
784 | up_write(&s->s_umount); |
785 | deactivate_super(s); |
786 | return ERR_PTR(error); |
787 | } |
788 | s->s_flags |= MS_ACTIVE; |
789 | } |
790 | do_remount_sb(s, flags, data, 0); |
791 | return s; |
792 | } |
793 | |
794 | EXPORT_SYMBOL(get_sb_single); |
795 | |
796 | struct vfsmount * |
797 | do_kern_mount(const char *fstype, int flags, const char *name, void *data) |
798 | { |
799 | struct file_system_type *type = get_fs_type(fstype); |
800 | struct super_block *sb = ERR_PTR(-ENOMEM); |
801 | struct vfsmount *mnt; |
802 | int error; |
803 | char *secdata = NULL; |
804 | |
805 | if (!type) |
806 | return ERR_PTR(-ENODEV); |
807 | |
808 | mnt = alloc_vfsmnt(name); |
809 | if (!mnt) |
810 | goto out; |
811 | |
812 | if (data) { |
813 | secdata = alloc_secdata(); |
814 | if (!secdata) { |
815 | sb = ERR_PTR(-ENOMEM); |
816 | goto out_mnt; |
817 | } |
818 | |
819 | error = security_sb_copy_data(type, data, secdata); |
820 | if (error) { |
821 | sb = ERR_PTR(error); |
822 | goto out_free_secdata; |
823 | } |
824 | } |
825 | |
826 | sb = type->get_sb(type, flags, name, data); |
827 | if (IS_ERR(sb)) |
828 | goto out_free_secdata; |
829 | error = security_sb_kern_mount(sb, secdata); |
830 | if (error) |
831 | goto out_sb; |
832 | mnt->mnt_sb = sb; |
833 | mnt->mnt_root = dget(sb->s_root); |
834 | mnt->mnt_mountpoint = sb->s_root; |
835 | mnt->mnt_parent = mnt; |
836 | mnt->mnt_namespace = current->namespace; |
837 | up_write(&sb->s_umount); |
838 | put_filesystem(type); |
839 | return mnt; |
840 | out_sb: |
841 | up_write(&sb->s_umount); |
842 | deactivate_super(sb); |
843 | sb = ERR_PTR(error); |
844 | out_free_secdata: |
845 | free_secdata(secdata); |
846 | out_mnt: |
847 | free_vfsmnt(mnt); |
848 | out: |
849 | put_filesystem(type); |
850 | return (struct vfsmount *)sb; |
851 | } |
852 | |
853 | EXPORT_SYMBOL_GPL(do_kern_mount); |
854 | |
855 | struct vfsmount *kern_mount(struct file_system_type *type) |
856 | { |
857 | return do_kern_mount(type->name, 0, type->name, NULL); |
858 | } |
859 | |
860 | EXPORT_SYMBOL(kern_mount); |