blob: 1943fdf655faca2d3d1810cca8b36ac80c9d3593 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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:
Jan Engelhardt96de0e22007-10-19 23:21:04 +020018 * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#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>
Ingo Molnar353ab6e2006-03-26 01:37:12 -080039#include <linux/mutex.h>
Dave Hansen49e0d022008-02-15 14:37:32 -080040#include <linux/file.h>
Arjan van de Venefaee192009-01-06 07:20:54 -080041#include <linux/async.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <asm/uaccess.h>
Al Viro6d59e7f2008-03-22 15:48:17 -040043#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046LIST_HEAD(super_blocks);
47DEFINE_SPINLOCK(sb_lock);
48
49/**
50 * alloc_super - create new superblock
Henrik Kretzschmarfe2bbc42006-09-06 00:03:41 -070051 * @type: filesystem type superblock should belong to
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 *
53 * Allocates and initializes a new &struct super_block. alloc_super()
54 * returns a pointer new superblock or %NULL if allocation had failed.
55 */
Ingo Molnarcf516242006-07-03 00:25:27 -070056static struct super_block *alloc_super(struct file_system_type *type)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057{
Oliver Neukum11b0b5a2006-03-25 03:08:13 -080058 struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 static struct super_operations default_op;
60
61 if (s) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 if (security_sb_alloc(s)) {
63 kfree(s);
64 s = NULL;
65 goto out;
66 }
67 INIT_LIST_HEAD(&s->s_dirty);
68 INIT_LIST_HEAD(&s->s_io);
Ken Chen0e0f4fc2007-10-16 23:30:38 -070069 INIT_LIST_HEAD(&s->s_more_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 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);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -070074 INIT_LIST_HEAD(&s->s_dentry_lru);
Arjan van de Venefaee192009-01-06 07:20:54 -080075 INIT_LIST_HEAD(&s->s_async_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 init_rwsem(&s->s_umount);
Ingo Molnar7892f2f2006-01-09 15:59:25 -080077 mutex_init(&s->s_lock);
Arjan van de Ven897c6ff2006-07-03 00:25:28 -070078 lockdep_set_class(&s->s_umount, &type->s_umount_key);
Ingo Molnarcf516242006-07-03 00:25:27 -070079 /*
80 * The locking rules for s_lock are up to the
81 * filesystem. For example ext3fs has different
82 * lock ordering than usbfs:
83 */
84 lockdep_set_class(&s->s_lock, &type->s_lock_key);
Peter Zijlstraada723d2009-02-18 14:48:30 -080085 /*
86 * sget() can have s_umount recursion.
87 *
88 * When it cannot find a suitable sb, it allocates a new
89 * one (this one), and tries again to find a suitable old
90 * one.
91 *
92 * In case that succeeds, it will acquire the s_umount
93 * lock of the old one. Since these are clearly distrinct
94 * locks, and this object isn't exposed yet, there's no
95 * risk of deadlocks.
96 *
97 * Annotate this by putting this lock in a different
98 * subclass.
99 */
100 down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 s->s_count = S_BIAS;
102 atomic_set(&s->s_active, 1);
Arjan van de Vena11f3a02006-03-23 03:00:33 -0800103 mutex_init(&s->s_vfs_rename_mutex);
Ingo Molnard3be9152006-03-23 03:00:29 -0800104 mutex_init(&s->s_dquot.dqio_mutex);
105 mutex_init(&s->s_dquot.dqonoff_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 init_rwsem(&s->s_dquot.dqptr_sem);
107 init_waitqueue_head(&s->s_wait_unfrozen);
108 s->s_maxbytes = MAX_NON_LFS;
109 s->dq_op = sb_dquot_ops;
110 s->s_qcop = sb_quotactl_ops;
111 s->s_op = &default_op;
112 s->s_time_gran = 1000000000;
113 }
114out:
115 return s;
116}
117
118/**
119 * destroy_super - frees a superblock
120 * @s: superblock to free
121 *
122 * Frees a superblock.
123 */
124static inline void destroy_super(struct super_block *s)
125{
126 security_sb_free(s);
Miklos Szeredi79c0b2d2007-05-08 00:25:43 -0700127 kfree(s->s_subtype);
Miklos Szeredib3b304a2008-02-08 04:21:35 -0800128 kfree(s->s_options);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 kfree(s);
130}
131
132/* Superblock refcounting */
133
134/*
135 * Drop a superblock's refcount. Returns non-zero if the superblock was
136 * destroyed. The caller must hold sb_lock.
137 */
Adrian Bunk6b09ae62008-04-29 00:58:54 -0700138static int __put_super(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
140 int ret = 0;
141
142 if (!--sb->s_count) {
143 destroy_super(sb);
144 ret = 1;
145 }
146 return ret;
147}
148
149/*
150 * Drop a superblock's refcount.
151 * Returns non-zero if the superblock is about to be destroyed and
152 * at least is already removed from super_blocks list, so if we are
153 * making a loop through super blocks then we need to restart.
154 * The caller must hold sb_lock.
155 */
156int __put_super_and_need_restart(struct super_block *sb)
157{
158 /* check for race with generic_shutdown_super() */
159 if (list_empty(&sb->s_list)) {
160 /* super block is removed, need to restart... */
161 __put_super(sb);
162 return 1;
163 }
164 /* can't be the last, since s_list is still in use */
165 sb->s_count--;
166 BUG_ON(sb->s_count == 0);
167 return 0;
168}
169
170/**
171 * put_super - drop a temporary reference to superblock
172 * @sb: superblock in question
173 *
174 * Drops a temporary reference, frees superblock if there's no
175 * references left.
176 */
177static void put_super(struct super_block *sb)
178{
179 spin_lock(&sb_lock);
180 __put_super(sb);
181 spin_unlock(&sb_lock);
182}
183
184
185/**
186 * deactivate_super - drop an active reference to superblock
187 * @s: superblock to deactivate
188 *
189 * Drops an active reference to superblock, acquiring a temprory one if
190 * there is no active references left. In that case we lock superblock,
191 * tell fs driver to shut it down and drop the temporary reference we
192 * had just acquired.
193 */
194void deactivate_super(struct super_block *s)
195{
196 struct file_system_type *fs = s->s_type;
197 if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
198 s->s_count -= S_BIAS-1;
199 spin_unlock(&sb_lock);
Jan Kara9e3509e2009-01-26 16:45:12 +0100200 vfs_dq_off(s, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 down_write(&s->s_umount);
202 fs->kill_sb(s);
203 put_filesystem(fs);
204 put_super(s);
205 }
206}
207
208EXPORT_SYMBOL(deactivate_super);
209
210/**
Al Viro74dbbdd2009-05-06 01:07:50 -0400211 * deactivate_locked_super - drop an active reference to superblock
212 * @s: superblock to deactivate
213 *
214 * Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that
215 * it does not unlock it until it's all over. As the result, it's safe to
216 * use to dispose of new superblock on ->get_sb() failure exits - nobody
217 * will see the sucker until it's all over. Equivalent using up_write +
218 * deactivate_super is safe for that purpose only if superblock is either
219 * safe to use or has NULL ->s_root when we unlock.
220 */
221void deactivate_locked_super(struct super_block *s)
222{
223 struct file_system_type *fs = s->s_type;
224 if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
225 s->s_count -= S_BIAS-1;
226 spin_unlock(&sb_lock);
227 vfs_dq_off(s, 0);
228 fs->kill_sb(s);
229 put_filesystem(fs);
230 put_super(s);
231 } else {
232 up_write(&s->s_umount);
233 }
234}
235
236EXPORT_SYMBOL(deactivate_locked_super);
237
238/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 * grab_super - acquire an active reference
240 * @s: reference we are trying to make active
241 *
242 * Tries to acquire an active reference. grab_super() is used when we
243 * had just found a superblock in super_blocks or fs_type->fs_supers
244 * and want to turn it into a full-blown active reference. grab_super()
245 * is called with sb_lock held and drops it. Returns 1 in case of
246 * success, 0 if we had failed (superblock contents was already dead or
247 * dying when grab_super() had been called).
248 */
Josh Triplett9c4dbee2006-09-29 01:59:29 -0700249static int grab_super(struct super_block *s) __releases(sb_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250{
251 s->s_count++;
252 spin_unlock(&sb_lock);
253 down_write(&s->s_umount);
254 if (s->s_root) {
255 spin_lock(&sb_lock);
256 if (s->s_count > S_BIAS) {
257 atomic_inc(&s->s_active);
258 s->s_count--;
259 spin_unlock(&sb_lock);
260 return 1;
261 }
262 spin_unlock(&sb_lock);
263 }
264 up_write(&s->s_umount);
265 put_super(s);
266 yield();
267 return 0;
268}
269
David Howellscf9a2ae2006-08-29 19:05:54 +0100270/*
Al Viro914e2632006-10-18 13:55:46 -0400271 * Superblock locking. We really ought to get rid of these two.
272 */
273void lock_super(struct super_block * sb)
274{
275 get_fs_excl();
276 mutex_lock(&sb->s_lock);
277}
278
279void unlock_super(struct super_block * sb)
280{
281 put_fs_excl();
282 mutex_unlock(&sb->s_lock);
283}
284
285EXPORT_SYMBOL(lock_super);
286EXPORT_SYMBOL(unlock_super);
287
288/*
David Howellscf9a2ae2006-08-29 19:05:54 +0100289 * Write out and wait upon all dirty data associated with this
290 * superblock. Filesystem data as well as the underlying block
291 * device. Takes the superblock lock. Requires a second blkdev
292 * flush by the caller to complete the operation.
293 */
294void __fsync_super(struct super_block *sb)
295{
296 sync_inodes_sb(sb, 0);
Jan Kara9e3509e2009-01-26 16:45:12 +0100297 vfs_dq_sync(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100298 lock_super(sb);
299 if (sb->s_dirt && sb->s_op->write_super)
300 sb->s_op->write_super(sb);
301 unlock_super(sb);
302 if (sb->s_op->sync_fs)
303 sb->s_op->sync_fs(sb, 1);
304 sync_blockdev(sb->s_bdev);
305 sync_inodes_sb(sb, 1);
306}
307
308/*
309 * Write out and wait upon all dirty data associated with this
310 * superblock. Filesystem data as well as the underlying block
311 * device. Takes the superblock lock.
312 */
313int fsync_super(struct super_block *sb)
314{
315 __fsync_super(sb);
316 return sync_blockdev(sb->s_bdev);
317}
David Howells800a9642009-04-03 16:42:40 +0100318EXPORT_SYMBOL_GPL(fsync_super);
David Howellscf9a2ae2006-08-29 19:05:54 +0100319
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320/**
321 * generic_shutdown_super - common helper for ->kill_sb()
322 * @sb: superblock to kill
323 *
324 * generic_shutdown_super() does all fs-independent work on superblock
325 * shutdown. Typical ->kill_sb() should pick all fs-specific objects
326 * that need destruction out of superblock, call generic_shutdown_super()
327 * and release aforementioned objects. Note: dentries and inodes _are_
328 * taken care of and do not need specific handling.
David Howellsc636ebd2006-10-11 01:22:19 -0700329 *
330 * Upon calling this function, the filesystem may no longer alter or
331 * rearrange the set of dentries belonging to this super_block, nor may it
332 * change the attachments of dentries to inodes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 */
334void generic_shutdown_super(struct super_block *sb)
335{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800336 const struct super_operations *sop = sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337
Arjan van de Venefaee192009-01-06 07:20:54 -0800338
David Howellsc636ebd2006-10-11 01:22:19 -0700339 if (sb->s_root) {
340 shrink_dcache_for_umount(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 fsync_super(sb);
342 lock_super(sb);
343 sb->s_flags &= ~MS_ACTIVE;
Arjan van de Venefaee192009-01-06 07:20:54 -0800344
345 /*
346 * wait for asynchronous fs operations to finish before going further
347 */
Cornelia Huck766ccb92009-01-20 15:31:31 +0100348 async_synchronize_full_domain(&sb->s_async_list);
Arjan van de Venefaee192009-01-06 07:20:54 -0800349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 /* bad name - it should be evict_inodes() */
351 invalidate_inodes(sb);
352 lock_kernel();
353
354 if (sop->write_super && sb->s_dirt)
355 sop->write_super(sb);
356 if (sop->put_super)
357 sop->put_super(sb);
358
359 /* Forget any remaining inodes */
360 if (invalidate_inodes(sb)) {
Dave Jones7b4fe292006-02-07 12:58:48 -0800361 printk("VFS: Busy inodes after unmount of %s. "
362 "Self-destruct in 5 seconds. Have a nice day...\n",
363 sb->s_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 }
365
366 unlock_kernel();
367 unlock_super(sb);
368 }
369 spin_lock(&sb_lock);
370 /* should be initialized for __put_super_and_need_restart() */
371 list_del_init(&sb->s_list);
372 list_del(&sb->s_instances);
373 spin_unlock(&sb_lock);
374 up_write(&sb->s_umount);
375}
376
377EXPORT_SYMBOL(generic_shutdown_super);
378
379/**
380 * sget - find or create a superblock
381 * @type: filesystem type superblock should belong to
382 * @test: comparison callback
383 * @set: setup callback
384 * @data: argument to each of them
385 */
386struct super_block *sget(struct file_system_type *type,
387 int (*test)(struct super_block *,void *),
388 int (*set)(struct super_block *,void *),
389 void *data)
390{
391 struct super_block *s = NULL;
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700392 struct super_block *old;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 int err;
394
395retry:
396 spin_lock(&sb_lock);
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700397 if (test) {
398 list_for_each_entry(old, &type->fs_supers, s_instances) {
399 if (!test(old, data))
400 continue;
401 if (!grab_super(old))
402 goto retry;
Li Zefana3cfbb52009-03-12 14:31:29 -0700403 if (s) {
404 up_write(&s->s_umount);
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700405 destroy_super(s);
Li Zefana3cfbb52009-03-12 14:31:29 -0700406 }
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700407 return old;
408 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 }
410 if (!s) {
411 spin_unlock(&sb_lock);
Ingo Molnarcf516242006-07-03 00:25:27 -0700412 s = alloc_super(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 if (!s)
414 return ERR_PTR(-ENOMEM);
415 goto retry;
416 }
417
418 err = set(s, data);
419 if (err) {
420 spin_unlock(&sb_lock);
Li Zefana3cfbb52009-03-12 14:31:29 -0700421 up_write(&s->s_umount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 destroy_super(s);
423 return ERR_PTR(err);
424 }
425 s->s_type = type;
426 strlcpy(s->s_id, type->name, sizeof(s->s_id));
427 list_add_tail(&s->s_list, &super_blocks);
428 list_add(&s->s_instances, &type->fs_supers);
429 spin_unlock(&sb_lock);
430 get_filesystem(type);
431 return s;
432}
433
434EXPORT_SYMBOL(sget);
435
436void drop_super(struct super_block *sb)
437{
438 up_read(&sb->s_umount);
439 put_super(sb);
440}
441
442EXPORT_SYMBOL(drop_super);
443
444static inline void write_super(struct super_block *sb)
445{
446 lock_super(sb);
447 if (sb->s_root && sb->s_dirt)
448 if (sb->s_op->write_super)
449 sb->s_op->write_super(sb);
450 unlock_super(sb);
451}
452
453/*
454 * Note: check the dirty flag before waiting, so we don't
455 * hold up the sync while mounting a device. (The newly
456 * mounted device won't need syncing.)
457 */
458void sync_supers(void)
459{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700460 struct super_block *sb;
461
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700463restart:
464 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 if (sb->s_dirt) {
466 sb->s_count++;
467 spin_unlock(&sb_lock);
468 down_read(&sb->s_umount);
469 write_super(sb);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700470 up_read(&sb->s_umount);
471 spin_lock(&sb_lock);
472 if (__put_super_and_need_restart(sb))
473 goto restart;
474 }
475 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 spin_unlock(&sb_lock);
477}
478
479/*
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200480 * Call the ->sync_fs super_op against all filesystems which are r/w and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 * which implement it.
482 *
483 * This operation is careful to avoid the livelock which could easily happen
484 * if two or more filesystems are being continuously dirtied. s_need_sync_fs
485 * is used only here. We set it against all filesystems and then clear it as
486 * we sync them. So redirtied filesystems are skipped.
487 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200488 * But if process A is currently running sync_filesystems and then process B
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 * calls sync_filesystems as well, process B will set all the s_need_sync_fs
490 * flags again, which will cause process A to resync everything. Fix that with
491 * a local mutex.
492 *
493 * (Fabian) Avoid sync_fs with clean fs & wait mode 0
494 */
495void sync_filesystems(int wait)
496{
497 struct super_block *sb;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800498 static DEFINE_MUTEX(mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800500 mutex_lock(&mutex); /* Could be down_interruptible */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700502 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (!sb->s_op->sync_fs)
504 continue;
505 if (sb->s_flags & MS_RDONLY)
506 continue;
507 sb->s_need_sync_fs = 1;
508 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509
510restart:
Kirill Korotaev618f0632005-06-23 00:09:54 -0700511 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 if (!sb->s_need_sync_fs)
513 continue;
514 sb->s_need_sync_fs = 0;
515 if (sb->s_flags & MS_RDONLY)
516 continue; /* hm. Was remounted r/o meanwhile */
517 sb->s_count++;
518 spin_unlock(&sb_lock);
519 down_read(&sb->s_umount);
Cornelia Huck766ccb92009-01-20 15:31:31 +0100520 async_synchronize_full_domain(&sb->s_async_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 if (sb->s_root && (wait || sb->s_dirt))
522 sb->s_op->sync_fs(sb, wait);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700523 up_read(&sb->s_umount);
524 /* restart only when sb is no longer on the list */
525 spin_lock(&sb_lock);
526 if (__put_super_and_need_restart(sb))
527 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 }
529 spin_unlock(&sb_lock);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800530 mutex_unlock(&mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531}
532
533/**
534 * get_super - get the superblock of a device
535 * @bdev: device to get the superblock for
536 *
537 * Scans the superblock list and finds the superblock of the file system
538 * mounted on the device given. %NULL is returned if no match is found.
539 */
540
541struct super_block * get_super(struct block_device *bdev)
542{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700543 struct super_block *sb;
544
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 if (!bdev)
546 return NULL;
Kirill Korotaev618f0632005-06-23 00:09:54 -0700547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700549rescan:
550 list_for_each_entry(sb, &super_blocks, s_list) {
551 if (sb->s_bdev == bdev) {
552 sb->s_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 spin_unlock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700554 down_read(&sb->s_umount);
555 if (sb->s_root)
556 return sb;
557 up_read(&sb->s_umount);
558 /* restart only when sb is no longer on the list */
559 spin_lock(&sb_lock);
560 if (__put_super_and_need_restart(sb))
561 goto rescan;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 }
563 }
564 spin_unlock(&sb_lock);
565 return NULL;
566}
567
568EXPORT_SYMBOL(get_super);
569
570struct super_block * user_get_super(dev_t dev)
571{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700572 struct super_block *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700575rescan:
576 list_for_each_entry(sb, &super_blocks, s_list) {
577 if (sb->s_dev == dev) {
578 sb->s_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 spin_unlock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700580 down_read(&sb->s_umount);
581 if (sb->s_root)
582 return sb;
583 up_read(&sb->s_umount);
584 /* restart only when sb is no longer on the list */
585 spin_lock(&sb_lock);
586 if (__put_super_and_need_restart(sb))
587 goto rescan;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 }
589 }
590 spin_unlock(&sb_lock);
591 return NULL;
592}
593
Heiko Carstens257ac262009-01-14 14:14:13 +0100594SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
596 struct super_block *s;
597 struct ustat tmp;
598 struct kstatfs sbuf;
599 int err = -EINVAL;
600
601 s = user_get_super(new_decode_dev(dev));
602 if (s == NULL)
603 goto out;
David Howells726c3342006-06-23 02:02:58 -0700604 err = vfs_statfs(s->s_root, &sbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 drop_super(s);
606 if (err)
607 goto out;
608
609 memset(&tmp,0,sizeof(struct ustat));
610 tmp.f_tfree = sbuf.f_bfree;
611 tmp.f_tinode = sbuf.f_ffree;
612
613 err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
614out:
615 return err;
616}
617
618/**
Randy Dunlapa6b91912008-03-19 17:01:00 -0700619 * mark_files_ro - mark all files read-only
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 * @sb: superblock in question
621 *
Randy Dunlapa6b91912008-03-19 17:01:00 -0700622 * All files are marked read-only. We don't care about pending
623 * delete files so this should be used in 'force' mode only.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 */
625
626static void mark_files_ro(struct super_block *sb)
627{
628 struct file *f;
629
Dave Hansen49e0d022008-02-15 14:37:32 -0800630retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 file_list_lock();
Eric Dumazet2f512012005-10-30 15:02:16 -0800632 list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
Dave Hansen49e0d022008-02-15 14:37:32 -0800633 struct vfsmount *mnt;
634 if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
635 continue;
636 if (!file_count(f))
637 continue;
638 if (!(f->f_mode & FMODE_WRITE))
639 continue;
640 f->f_mode &= ~FMODE_WRITE;
Dave Hansenad775f52008-02-15 14:38:01 -0800641 if (file_check_writeable(f) != 0)
642 continue;
643 file_release_write(f);
Dave Hansen49e0d022008-02-15 14:37:32 -0800644 mnt = mntget(f->f_path.mnt);
645 file_list_unlock();
646 /*
647 * This can sleep, so we can't hold
648 * the file_list_lock() spinlock.
649 */
650 mnt_drop_write(mnt);
651 mntput(mnt);
652 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 }
654 file_list_unlock();
655}
656
657/**
658 * do_remount_sb - asks filesystem to change mount options.
659 * @sb: superblock in question
660 * @flags: numeric part of options
661 * @data: the rest of options
662 * @force: whether or not to force the change
663 *
664 * Alters the mount options of a mounted file system.
665 */
666int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
667{
668 int retval;
Jan Kara0ff5af82008-04-28 02:14:33 -0700669 int remount_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
David Howells93614012006-09-30 20:45:40 +0200671#ifdef CONFIG_BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
673 return -EACCES;
David Howells93614012006-09-30 20:45:40 +0200674#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 if (flags & MS_RDONLY)
676 acct_auto_close(sb);
677 shrink_dcache_sb(sb);
678 fsync_super(sb);
679
680 /* If we are remounting RDONLY and current sb is read/write,
681 make sure there are no rw files opened */
682 if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
683 if (force)
684 mark_files_ro(sb);
685 else if (!fs_may_remount_ro(sb))
686 return -EBUSY;
Jan Kara9e3509e2009-01-26 16:45:12 +0100687 retval = vfs_dq_off(sb, 1);
Jan Kara0ff5af82008-04-28 02:14:33 -0700688 if (retval < 0 && retval != -ENOSYS)
689 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 }
Jan Kara0ff5af82008-04-28 02:14:33 -0700691 remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692
693 if (sb->s_op->remount_fs) {
694 lock_super(sb);
695 retval = sb->s_op->remount_fs(sb, &flags, data);
696 unlock_super(sb);
697 if (retval)
698 return retval;
699 }
700 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
Jan Kara0ff5af82008-04-28 02:14:33 -0700701 if (remount_rw)
Jan Kara9e3509e2009-01-26 16:45:12 +0100702 vfs_dq_quota_on_remount(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 return 0;
704}
705
Jens Axboea2a95372009-03-17 09:38:40 +0100706static void do_emergency_remount(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707{
708 struct super_block *sb;
709
710 spin_lock(&sb_lock);
711 list_for_each_entry(sb, &super_blocks, s_list) {
712 sb->s_count++;
713 spin_unlock(&sb_lock);
714 down_read(&sb->s_umount);
715 if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
716 /*
717 * ->remount_fs needs lock_kernel().
718 *
719 * What lock protects sb->s_flags??
720 */
721 lock_kernel();
722 do_remount_sb(sb, MS_RDONLY, NULL, 1);
723 unlock_kernel();
724 }
725 drop_super(sb);
726 spin_lock(&sb_lock);
727 }
728 spin_unlock(&sb_lock);
Jens Axboea2a95372009-03-17 09:38:40 +0100729 kfree(work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 printk("Emergency Remount complete\n");
731}
732
733void emergency_remount(void)
734{
Jens Axboea2a95372009-03-17 09:38:40 +0100735 struct work_struct *work;
736
737 work = kmalloc(sizeof(*work), GFP_ATOMIC);
738 if (work) {
739 INIT_WORK(work, do_emergency_remount);
740 schedule_work(work);
741 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742}
743
744/*
745 * Unnamed block devices are dummy devices used by virtual
746 * filesystems which don't use real block-devices. -- jrs
747 */
748
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400749static DEFINE_IDA(unnamed_dev_ida);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
751
752int set_anon_super(struct super_block *s, void *data)
753{
754 int dev;
755 int error;
756
757 retry:
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400758 if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 return -ENOMEM;
760 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400761 error = ida_get_new(&unnamed_dev_ida, &dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 spin_unlock(&unnamed_dev_lock);
763 if (error == -EAGAIN)
764 /* We raced and lost with another CPU. */
765 goto retry;
766 else if (error)
767 return -EAGAIN;
768
769 if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
770 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400771 ida_remove(&unnamed_dev_ida, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 spin_unlock(&unnamed_dev_lock);
773 return -EMFILE;
774 }
775 s->s_dev = MKDEV(0, dev & MINORMASK);
776 return 0;
777}
778
779EXPORT_SYMBOL(set_anon_super);
780
781void kill_anon_super(struct super_block *sb)
782{
783 int slot = MINOR(sb->s_dev);
784
785 generic_shutdown_super(sb);
786 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400787 ida_remove(&unnamed_dev_ida, slot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 spin_unlock(&unnamed_dev_lock);
789}
790
791EXPORT_SYMBOL(kill_anon_super);
792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793void kill_litter_super(struct super_block *sb)
794{
795 if (sb->s_root)
796 d_genocide(sb->s_root);
797 kill_anon_super(sb);
798}
799
800EXPORT_SYMBOL(kill_litter_super);
801
Serge E. Hallyn909e6d92009-04-06 19:01:07 -0700802static int ns_test_super(struct super_block *sb, void *data)
803{
804 return sb->s_fs_info == data;
805}
806
807static int ns_set_super(struct super_block *sb, void *data)
808{
809 sb->s_fs_info = data;
810 return set_anon_super(sb, NULL);
811}
812
813int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
814 int (*fill_super)(struct super_block *, void *, int),
815 struct vfsmount *mnt)
816{
817 struct super_block *sb;
818
819 sb = sget(fs_type, ns_test_super, ns_set_super, data);
820 if (IS_ERR(sb))
821 return PTR_ERR(sb);
822
823 if (!sb->s_root) {
824 int err;
825 sb->s_flags = flags;
826 err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
827 if (err) {
Al Viro74dbbdd2009-05-06 01:07:50 -0400828 deactivate_locked_super(sb);
Serge E. Hallyn909e6d92009-04-06 19:01:07 -0700829 return err;
830 }
831
832 sb->s_flags |= MS_ACTIVE;
833 }
834
835 simple_set_mnt(mnt, sb);
836 return 0;
837}
838
839EXPORT_SYMBOL(get_sb_ns);
840
David Howells93614012006-09-30 20:45:40 +0200841#ifdef CONFIG_BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842static int set_bdev_super(struct super_block *s, void *data)
843{
844 s->s_bdev = data;
845 s->s_dev = s->s_bdev->bd_dev;
846 return 0;
847}
848
849static int test_bdev_super(struct super_block *s, void *data)
850{
851 return (void *)s->s_bdev == data;
852}
853
David Howells454e2392006-06-23 02:02:57 -0700854int get_sb_bdev(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 int flags, const char *dev_name, void *data,
David Howells454e2392006-06-23 02:02:57 -0700856 int (*fill_super)(struct super_block *, void *, int),
857 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858{
859 struct block_device *bdev;
860 struct super_block *s;
Al Viro30c40d22008-02-22 19:50:45 -0500861 fmode_t mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 int error = 0;
863
Al Viro30c40d22008-02-22 19:50:45 -0500864 if (!(flags & MS_RDONLY))
865 mode |= FMODE_WRITE;
866
867 bdev = open_bdev_exclusive(dev_name, mode, fs_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 if (IS_ERR(bdev))
David Howells454e2392006-06-23 02:02:57 -0700869 return PTR_ERR(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
871 /*
872 * once the super is inserted into the list by sget, s_umount
873 * will protect the lockfs code from trying to start a snapshot
874 * while we are mounting
875 */
David Chinnerf73ca1b2007-01-10 23:15:41 -0800876 down(&bdev->bd_mount_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
David Chinnerf73ca1b2007-01-10 23:15:41 -0800878 up(&bdev->bd_mount_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700880 goto error_s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
882 if (s->s_root) {
883 if ((flags ^ s->s_flags) & MS_RDONLY) {
Al Viro74dbbdd2009-05-06 01:07:50 -0400884 deactivate_locked_super(s);
David Howells454e2392006-06-23 02:02:57 -0700885 error = -EBUSY;
886 goto error_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 }
David Howells454e2392006-06-23 02:02:57 -0700888
Al Viro30c40d22008-02-22 19:50:45 -0500889 close_bdev_exclusive(bdev, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 } else {
891 char b[BDEVNAME_SIZE];
892
893 s->s_flags = flags;
Al Viro30c40d22008-02-22 19:50:45 -0500894 s->s_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
Pekka Enberge78c9a02006-01-08 01:03:39 -0800896 sb_set_blocksize(s, block_size(bdev));
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800897 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 if (error) {
Al Viro74dbbdd2009-05-06 01:07:50 -0400899 deactivate_locked_super(s);
David Howells454e2392006-06-23 02:02:57 -0700900 goto error;
Greg Kroah-Hartmanfa675762006-02-22 09:39:02 -0800901 }
David Howells454e2392006-06-23 02:02:57 -0700902
903 s->s_flags |= MS_ACTIVE;
Theodore Ts'o87d8fe12009-01-03 09:47:09 -0500904 bdev->bd_super = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 }
906
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800907 simple_set_mnt(mnt, s);
908 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909
David Howells454e2392006-06-23 02:02:57 -0700910error_s:
911 error = PTR_ERR(s);
912error_bdev:
Al Viro30c40d22008-02-22 19:50:45 -0500913 close_bdev_exclusive(bdev, mode);
David Howells454e2392006-06-23 02:02:57 -0700914error:
915 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916}
917
918EXPORT_SYMBOL(get_sb_bdev);
919
920void kill_block_super(struct super_block *sb)
921{
922 struct block_device *bdev = sb->s_bdev;
Al Viro30c40d22008-02-22 19:50:45 -0500923 fmode_t mode = sb->s_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
H Hartley Sweetenddbaaf32009-04-29 20:14:57 -0400925 bdev->bd_super = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 generic_shutdown_super(sb);
927 sync_blockdev(bdev);
Al Viro30c40d22008-02-22 19:50:45 -0500928 close_bdev_exclusive(bdev, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929}
930
931EXPORT_SYMBOL(kill_block_super);
David Howells93614012006-09-30 20:45:40 +0200932#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
David Howells454e2392006-06-23 02:02:57 -0700934int get_sb_nodev(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 int flags, void *data,
David Howells454e2392006-06-23 02:02:57 -0700936 int (*fill_super)(struct super_block *, void *, int),
937 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938{
939 int error;
940 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
941
942 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700943 return PTR_ERR(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
945 s->s_flags = flags;
946
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800947 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 if (error) {
Al Viro74dbbdd2009-05-06 01:07:50 -0400949 deactivate_locked_super(s);
David Howells454e2392006-06-23 02:02:57 -0700950 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 }
952 s->s_flags |= MS_ACTIVE;
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800953 simple_set_mnt(mnt, s);
954 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955}
956
957EXPORT_SYMBOL(get_sb_nodev);
958
959static int compare_single(struct super_block *s, void *p)
960{
961 return 1;
962}
963
David Howells454e2392006-06-23 02:02:57 -0700964int get_sb_single(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 int flags, void *data,
David Howells454e2392006-06-23 02:02:57 -0700966 int (*fill_super)(struct super_block *, void *, int),
967 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968{
969 struct super_block *s;
970 int error;
971
972 s = sget(fs_type, compare_single, set_anon_super, NULL);
973 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700974 return PTR_ERR(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 if (!s->s_root) {
976 s->s_flags = flags;
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800977 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 if (error) {
Al Viro74dbbdd2009-05-06 01:07:50 -0400979 deactivate_locked_super(s);
David Howells454e2392006-06-23 02:02:57 -0700980 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 }
982 s->s_flags |= MS_ACTIVE;
983 }
984 do_remount_sb(s, flags, data, 0);
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800985 simple_set_mnt(mnt, s);
986 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987}
988
989EXPORT_SYMBOL(get_sb_single);
990
991struct vfsmount *
Trond Myklebustbb4a58b2006-06-09 09:34:15 -0400992vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 struct vfsmount *mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 char *secdata = NULL;
David Howells454e2392006-06-23 02:02:57 -0700996 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997
998 if (!type)
999 return ERR_PTR(-ENODEV);
1000
David Howells454e2392006-06-23 02:02:57 -07001001 error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 mnt = alloc_vfsmnt(name);
1003 if (!mnt)
1004 goto out;
1005
Eric Parise0007522008-03-05 10:31:54 -05001006 if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 secdata = alloc_secdata();
David Howells454e2392006-06-23 02:02:57 -07001008 if (!secdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 goto out_mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010
Eric Parise0007522008-03-05 10:31:54 -05001011 error = security_sb_copy_data(data, secdata);
David Howells454e2392006-06-23 02:02:57 -07001012 if (error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 goto out_free_secdata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 }
1015
David Howells454e2392006-06-23 02:02:57 -07001016 error = type->get_sb(type, flags, name, data, mnt);
1017 if (error < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 goto out_free_secdata;
Lee Schermerhornb4c07bc2007-07-15 23:40:54 -07001019 BUG_ON(!mnt->mnt_sb);
David Howells454e2392006-06-23 02:02:57 -07001020
James Morris12204e22008-12-19 10:44:42 +11001021 error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 if (error)
1023 goto out_sb;
David Howells454e2392006-06-23 02:02:57 -07001024
1025 mnt->mnt_mountpoint = mnt->mnt_root;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 mnt->mnt_parent = mnt;
David Howells454e2392006-06-23 02:02:57 -07001027 up_write(&mnt->mnt_sb->s_umount);
Gerald Schaefer8680e222005-06-21 17:15:16 -07001028 free_secdata(secdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 return mnt;
1030out_sb:
David Howells454e2392006-06-23 02:02:57 -07001031 dput(mnt->mnt_root);
Al Viro74dbbdd2009-05-06 01:07:50 -04001032 deactivate_locked_super(mnt->mnt_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033out_free_secdata:
1034 free_secdata(secdata);
1035out_mnt:
1036 free_vfsmnt(mnt);
1037out:
David Howells454e2392006-06-23 02:02:57 -07001038 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039}
1040
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001041EXPORT_SYMBOL_GPL(vfs_kern_mount);
1042
Miklos Szeredi79c0b2d2007-05-08 00:25:43 -07001043static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
1044{
1045 int err;
1046 const char *subtype = strchr(fstype, '.');
1047 if (subtype) {
1048 subtype++;
1049 err = -EINVAL;
1050 if (!subtype[0])
1051 goto err;
1052 } else
1053 subtype = "";
1054
1055 mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
1056 err = -ENOMEM;
1057 if (!mnt->mnt_sb->s_subtype)
1058 goto err;
1059 return mnt;
1060
1061 err:
1062 mntput(mnt);
1063 return ERR_PTR(err);
1064}
1065
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001066struct vfsmount *
1067do_kern_mount(const char *fstype, int flags, const char *name, void *data)
1068{
1069 struct file_system_type *type = get_fs_type(fstype);
1070 struct vfsmount *mnt;
1071 if (!type)
1072 return ERR_PTR(-ENODEV);
1073 mnt = vfs_kern_mount(type, flags, name, data);
Miklos Szeredi79c0b2d2007-05-08 00:25:43 -07001074 if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
1075 !mnt->mnt_sb->s_subtype)
1076 mnt = fs_set_subtype(mnt, fstype);
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001077 put_filesystem(type);
1078 return mnt;
1079}
Al Viro8a4e98d2008-02-24 01:43:03 -05001080EXPORT_SYMBOL_GPL(do_kern_mount);
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001081
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001082struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083{
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001084 return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085}
1086
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001087EXPORT_SYMBOL_GPL(kern_mount_data);