blob: 77cb4ec919b9a7bf941a3effe524c180343d8dee [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/**
211 * grab_super - acquire an active reference
212 * @s: reference we are trying to make active
213 *
214 * Tries to acquire an active reference. grab_super() is used when we
215 * had just found a superblock in super_blocks or fs_type->fs_supers
216 * and want to turn it into a full-blown active reference. grab_super()
217 * is called with sb_lock held and drops it. Returns 1 in case of
218 * success, 0 if we had failed (superblock contents was already dead or
219 * dying when grab_super() had been called).
220 */
Josh Triplett9c4dbee2006-09-29 01:59:29 -0700221static int grab_super(struct super_block *s) __releases(sb_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222{
223 s->s_count++;
224 spin_unlock(&sb_lock);
225 down_write(&s->s_umount);
226 if (s->s_root) {
227 spin_lock(&sb_lock);
228 if (s->s_count > S_BIAS) {
229 atomic_inc(&s->s_active);
230 s->s_count--;
231 spin_unlock(&sb_lock);
232 return 1;
233 }
234 spin_unlock(&sb_lock);
235 }
236 up_write(&s->s_umount);
237 put_super(s);
238 yield();
239 return 0;
240}
241
David Howellscf9a2ae2006-08-29 19:05:54 +0100242/*
Al Viro914e2632006-10-18 13:55:46 -0400243 * Superblock locking. We really ought to get rid of these two.
244 */
245void lock_super(struct super_block * sb)
246{
247 get_fs_excl();
248 mutex_lock(&sb->s_lock);
249}
250
251void unlock_super(struct super_block * sb)
252{
253 put_fs_excl();
254 mutex_unlock(&sb->s_lock);
255}
256
257EXPORT_SYMBOL(lock_super);
258EXPORT_SYMBOL(unlock_super);
259
260/*
David Howellscf9a2ae2006-08-29 19:05:54 +0100261 * Write out and wait upon all dirty data associated with this
262 * superblock. Filesystem data as well as the underlying block
263 * device. Takes the superblock lock. Requires a second blkdev
264 * flush by the caller to complete the operation.
265 */
266void __fsync_super(struct super_block *sb)
267{
268 sync_inodes_sb(sb, 0);
Jan Kara9e3509e2009-01-26 16:45:12 +0100269 vfs_dq_sync(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100270 lock_super(sb);
271 if (sb->s_dirt && sb->s_op->write_super)
272 sb->s_op->write_super(sb);
273 unlock_super(sb);
274 if (sb->s_op->sync_fs)
275 sb->s_op->sync_fs(sb, 1);
276 sync_blockdev(sb->s_bdev);
277 sync_inodes_sb(sb, 1);
278}
279
280/*
281 * Write out and wait upon all dirty data associated with this
282 * superblock. Filesystem data as well as the underlying block
283 * device. Takes the superblock lock.
284 */
285int fsync_super(struct super_block *sb)
286{
287 __fsync_super(sb);
288 return sync_blockdev(sb->s_bdev);
289}
David Howells800a9642009-04-03 16:42:40 +0100290EXPORT_SYMBOL_GPL(fsync_super);
David Howellscf9a2ae2006-08-29 19:05:54 +0100291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292/**
293 * generic_shutdown_super - common helper for ->kill_sb()
294 * @sb: superblock to kill
295 *
296 * generic_shutdown_super() does all fs-independent work on superblock
297 * shutdown. Typical ->kill_sb() should pick all fs-specific objects
298 * that need destruction out of superblock, call generic_shutdown_super()
299 * and release aforementioned objects. Note: dentries and inodes _are_
300 * taken care of and do not need specific handling.
David Howellsc636ebd2006-10-11 01:22:19 -0700301 *
302 * Upon calling this function, the filesystem may no longer alter or
303 * rearrange the set of dentries belonging to this super_block, nor may it
304 * change the attachments of dentries to inodes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 */
306void generic_shutdown_super(struct super_block *sb)
307{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800308 const struct super_operations *sop = sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
Arjan van de Venefaee192009-01-06 07:20:54 -0800310
David Howellsc636ebd2006-10-11 01:22:19 -0700311 if (sb->s_root) {
312 shrink_dcache_for_umount(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 fsync_super(sb);
314 lock_super(sb);
315 sb->s_flags &= ~MS_ACTIVE;
Arjan van de Venefaee192009-01-06 07:20:54 -0800316
317 /*
318 * wait for asynchronous fs operations to finish before going further
319 */
Cornelia Huck766ccb92009-01-20 15:31:31 +0100320 async_synchronize_full_domain(&sb->s_async_list);
Arjan van de Venefaee192009-01-06 07:20:54 -0800321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 /* bad name - it should be evict_inodes() */
323 invalidate_inodes(sb);
324 lock_kernel();
325
326 if (sop->write_super && sb->s_dirt)
327 sop->write_super(sb);
328 if (sop->put_super)
329 sop->put_super(sb);
330
331 /* Forget any remaining inodes */
332 if (invalidate_inodes(sb)) {
Dave Jones7b4fe292006-02-07 12:58:48 -0800333 printk("VFS: Busy inodes after unmount of %s. "
334 "Self-destruct in 5 seconds. Have a nice day...\n",
335 sb->s_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 }
337
338 unlock_kernel();
339 unlock_super(sb);
340 }
341 spin_lock(&sb_lock);
342 /* should be initialized for __put_super_and_need_restart() */
343 list_del_init(&sb->s_list);
344 list_del(&sb->s_instances);
345 spin_unlock(&sb_lock);
346 up_write(&sb->s_umount);
347}
348
349EXPORT_SYMBOL(generic_shutdown_super);
350
351/**
352 * sget - find or create a superblock
353 * @type: filesystem type superblock should belong to
354 * @test: comparison callback
355 * @set: setup callback
356 * @data: argument to each of them
357 */
358struct super_block *sget(struct file_system_type *type,
359 int (*test)(struct super_block *,void *),
360 int (*set)(struct super_block *,void *),
361 void *data)
362{
363 struct super_block *s = NULL;
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700364 struct super_block *old;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 int err;
366
367retry:
368 spin_lock(&sb_lock);
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700369 if (test) {
370 list_for_each_entry(old, &type->fs_supers, s_instances) {
371 if (!test(old, data))
372 continue;
373 if (!grab_super(old))
374 goto retry;
Li Zefana3cfbb52009-03-12 14:31:29 -0700375 if (s) {
376 up_write(&s->s_umount);
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700377 destroy_super(s);
Li Zefana3cfbb52009-03-12 14:31:29 -0700378 }
Matthias Kaehlcked4730122007-10-18 23:39:57 -0700379 return old;
380 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 }
382 if (!s) {
383 spin_unlock(&sb_lock);
Ingo Molnarcf516242006-07-03 00:25:27 -0700384 s = alloc_super(type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 if (!s)
386 return ERR_PTR(-ENOMEM);
387 goto retry;
388 }
389
390 err = set(s, data);
391 if (err) {
392 spin_unlock(&sb_lock);
Li Zefana3cfbb52009-03-12 14:31:29 -0700393 up_write(&s->s_umount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 destroy_super(s);
395 return ERR_PTR(err);
396 }
397 s->s_type = type;
398 strlcpy(s->s_id, type->name, sizeof(s->s_id));
399 list_add_tail(&s->s_list, &super_blocks);
400 list_add(&s->s_instances, &type->fs_supers);
401 spin_unlock(&sb_lock);
402 get_filesystem(type);
403 return s;
404}
405
406EXPORT_SYMBOL(sget);
407
408void drop_super(struct super_block *sb)
409{
410 up_read(&sb->s_umount);
411 put_super(sb);
412}
413
414EXPORT_SYMBOL(drop_super);
415
416static inline void write_super(struct super_block *sb)
417{
418 lock_super(sb);
419 if (sb->s_root && sb->s_dirt)
420 if (sb->s_op->write_super)
421 sb->s_op->write_super(sb);
422 unlock_super(sb);
423}
424
425/*
426 * Note: check the dirty flag before waiting, so we don't
427 * hold up the sync while mounting a device. (The newly
428 * mounted device won't need syncing.)
429 */
430void sync_supers(void)
431{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700432 struct super_block *sb;
433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700435restart:
436 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 if (sb->s_dirt) {
438 sb->s_count++;
439 spin_unlock(&sb_lock);
440 down_read(&sb->s_umount);
441 write_super(sb);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700442 up_read(&sb->s_umount);
443 spin_lock(&sb_lock);
444 if (__put_super_and_need_restart(sb))
445 goto restart;
446 }
447 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 spin_unlock(&sb_lock);
449}
450
451/*
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200452 * Call the ->sync_fs super_op against all filesystems which are r/w and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 * which implement it.
454 *
455 * This operation is careful to avoid the livelock which could easily happen
456 * if two or more filesystems are being continuously dirtied. s_need_sync_fs
457 * is used only here. We set it against all filesystems and then clear it as
458 * we sync them. So redirtied filesystems are skipped.
459 *
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +0200460 * But if process A is currently running sync_filesystems and then process B
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 * calls sync_filesystems as well, process B will set all the s_need_sync_fs
462 * flags again, which will cause process A to resync everything. Fix that with
463 * a local mutex.
464 *
465 * (Fabian) Avoid sync_fs with clean fs & wait mode 0
466 */
467void sync_filesystems(int wait)
468{
469 struct super_block *sb;
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800470 static DEFINE_MUTEX(mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800472 mutex_lock(&mutex); /* Could be down_interruptible */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700474 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (!sb->s_op->sync_fs)
476 continue;
477 if (sb->s_flags & MS_RDONLY)
478 continue;
479 sb->s_need_sync_fs = 1;
480 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481
482restart:
Kirill Korotaev618f0632005-06-23 00:09:54 -0700483 list_for_each_entry(sb, &super_blocks, s_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 if (!sb->s_need_sync_fs)
485 continue;
486 sb->s_need_sync_fs = 0;
487 if (sb->s_flags & MS_RDONLY)
488 continue; /* hm. Was remounted r/o meanwhile */
489 sb->s_count++;
490 spin_unlock(&sb_lock);
491 down_read(&sb->s_umount);
Cornelia Huck766ccb92009-01-20 15:31:31 +0100492 async_synchronize_full_domain(&sb->s_async_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 if (sb->s_root && (wait || sb->s_dirt))
494 sb->s_op->sync_fs(sb, wait);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700495 up_read(&sb->s_umount);
496 /* restart only when sb is no longer on the list */
497 spin_lock(&sb_lock);
498 if (__put_super_and_need_restart(sb))
499 goto restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 }
501 spin_unlock(&sb_lock);
Ingo Molnar353ab6e2006-03-26 01:37:12 -0800502 mutex_unlock(&mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503}
504
505/**
506 * get_super - get the superblock of a device
507 * @bdev: device to get the superblock for
508 *
509 * Scans the superblock list and finds the superblock of the file system
510 * mounted on the device given. %NULL is returned if no match is found.
511 */
512
513struct super_block * get_super(struct block_device *bdev)
514{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700515 struct super_block *sb;
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 if (!bdev)
518 return NULL;
Kirill Korotaev618f0632005-06-23 00:09:54 -0700519
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700521rescan:
522 list_for_each_entry(sb, &super_blocks, s_list) {
523 if (sb->s_bdev == bdev) {
524 sb->s_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 spin_unlock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700526 down_read(&sb->s_umount);
527 if (sb->s_root)
528 return sb;
529 up_read(&sb->s_umount);
530 /* restart only when sb is no longer on the list */
531 spin_lock(&sb_lock);
532 if (__put_super_and_need_restart(sb))
533 goto rescan;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 }
535 }
536 spin_unlock(&sb_lock);
537 return NULL;
538}
539
540EXPORT_SYMBOL(get_super);
541
542struct super_block * user_get_super(dev_t dev)
543{
Kirill Korotaev618f0632005-06-23 00:09:54 -0700544 struct super_block *sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 spin_lock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700547rescan:
548 list_for_each_entry(sb, &super_blocks, s_list) {
549 if (sb->s_dev == dev) {
550 sb->s_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 spin_unlock(&sb_lock);
Kirill Korotaev618f0632005-06-23 00:09:54 -0700552 down_read(&sb->s_umount);
553 if (sb->s_root)
554 return sb;
555 up_read(&sb->s_umount);
556 /* restart only when sb is no longer on the list */
557 spin_lock(&sb_lock);
558 if (__put_super_and_need_restart(sb))
559 goto rescan;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 }
561 }
562 spin_unlock(&sb_lock);
563 return NULL;
564}
565
Heiko Carstens257ac262009-01-14 14:14:13 +0100566SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567{
568 struct super_block *s;
569 struct ustat tmp;
570 struct kstatfs sbuf;
571 int err = -EINVAL;
572
573 s = user_get_super(new_decode_dev(dev));
574 if (s == NULL)
575 goto out;
David Howells726c3342006-06-23 02:02:58 -0700576 err = vfs_statfs(s->s_root, &sbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 drop_super(s);
578 if (err)
579 goto out;
580
581 memset(&tmp,0,sizeof(struct ustat));
582 tmp.f_tfree = sbuf.f_bfree;
583 tmp.f_tinode = sbuf.f_ffree;
584
585 err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
586out:
587 return err;
588}
589
590/**
Randy Dunlapa6b91912008-03-19 17:01:00 -0700591 * mark_files_ro - mark all files read-only
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 * @sb: superblock in question
593 *
Randy Dunlapa6b91912008-03-19 17:01:00 -0700594 * All files are marked read-only. We don't care about pending
595 * delete files so this should be used in 'force' mode only.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 */
597
598static void mark_files_ro(struct super_block *sb)
599{
600 struct file *f;
601
Dave Hansen49e0d022008-02-15 14:37:32 -0800602retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 file_list_lock();
Eric Dumazet2f512012005-10-30 15:02:16 -0800604 list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
Dave Hansen49e0d022008-02-15 14:37:32 -0800605 struct vfsmount *mnt;
606 if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
607 continue;
608 if (!file_count(f))
609 continue;
610 if (!(f->f_mode & FMODE_WRITE))
611 continue;
612 f->f_mode &= ~FMODE_WRITE;
Dave Hansenad775f52008-02-15 14:38:01 -0800613 if (file_check_writeable(f) != 0)
614 continue;
615 file_release_write(f);
Dave Hansen49e0d022008-02-15 14:37:32 -0800616 mnt = mntget(f->f_path.mnt);
617 file_list_unlock();
618 /*
619 * This can sleep, so we can't hold
620 * the file_list_lock() spinlock.
621 */
622 mnt_drop_write(mnt);
623 mntput(mnt);
624 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 }
626 file_list_unlock();
627}
628
629/**
630 * do_remount_sb - asks filesystem to change mount options.
631 * @sb: superblock in question
632 * @flags: numeric part of options
633 * @data: the rest of options
634 * @force: whether or not to force the change
635 *
636 * Alters the mount options of a mounted file system.
637 */
638int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
639{
640 int retval;
Jan Kara0ff5af82008-04-28 02:14:33 -0700641 int remount_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642
David Howells93614012006-09-30 20:45:40 +0200643#ifdef CONFIG_BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
645 return -EACCES;
David Howells93614012006-09-30 20:45:40 +0200646#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 if (flags & MS_RDONLY)
648 acct_auto_close(sb);
649 shrink_dcache_sb(sb);
650 fsync_super(sb);
651
652 /* If we are remounting RDONLY and current sb is read/write,
653 make sure there are no rw files opened */
654 if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
655 if (force)
656 mark_files_ro(sb);
657 else if (!fs_may_remount_ro(sb))
658 return -EBUSY;
Jan Kara9e3509e2009-01-26 16:45:12 +0100659 retval = vfs_dq_off(sb, 1);
Jan Kara0ff5af82008-04-28 02:14:33 -0700660 if (retval < 0 && retval != -ENOSYS)
661 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 }
Jan Kara0ff5af82008-04-28 02:14:33 -0700663 remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
665 if (sb->s_op->remount_fs) {
666 lock_super(sb);
667 retval = sb->s_op->remount_fs(sb, &flags, data);
668 unlock_super(sb);
669 if (retval)
670 return retval;
671 }
672 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
Jan Kara0ff5af82008-04-28 02:14:33 -0700673 if (remount_rw)
Jan Kara9e3509e2009-01-26 16:45:12 +0100674 vfs_dq_quota_on_remount(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 return 0;
676}
677
Jens Axboea2a95372009-03-17 09:38:40 +0100678static void do_emergency_remount(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679{
680 struct super_block *sb;
681
682 spin_lock(&sb_lock);
683 list_for_each_entry(sb, &super_blocks, s_list) {
684 sb->s_count++;
685 spin_unlock(&sb_lock);
686 down_read(&sb->s_umount);
687 if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
688 /*
689 * ->remount_fs needs lock_kernel().
690 *
691 * What lock protects sb->s_flags??
692 */
693 lock_kernel();
694 do_remount_sb(sb, MS_RDONLY, NULL, 1);
695 unlock_kernel();
696 }
697 drop_super(sb);
698 spin_lock(&sb_lock);
699 }
700 spin_unlock(&sb_lock);
Jens Axboea2a95372009-03-17 09:38:40 +0100701 kfree(work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 printk("Emergency Remount complete\n");
703}
704
705void emergency_remount(void)
706{
Jens Axboea2a95372009-03-17 09:38:40 +0100707 struct work_struct *work;
708
709 work = kmalloc(sizeof(*work), GFP_ATOMIC);
710 if (work) {
711 INIT_WORK(work, do_emergency_remount);
712 schedule_work(work);
713 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714}
715
716/*
717 * Unnamed block devices are dummy devices used by virtual
718 * filesystems which don't use real block-devices. -- jrs
719 */
720
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400721static DEFINE_IDA(unnamed_dev_ida);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
723
724int set_anon_super(struct super_block *s, void *data)
725{
726 int dev;
727 int error;
728
729 retry:
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400730 if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 return -ENOMEM;
732 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400733 error = ida_get_new(&unnamed_dev_ida, &dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 spin_unlock(&unnamed_dev_lock);
735 if (error == -EAGAIN)
736 /* We raced and lost with another CPU. */
737 goto retry;
738 else if (error)
739 return -EAGAIN;
740
741 if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
742 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400743 ida_remove(&unnamed_dev_ida, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 spin_unlock(&unnamed_dev_lock);
745 return -EMFILE;
746 }
747 s->s_dev = MKDEV(0, dev & MINORMASK);
748 return 0;
749}
750
751EXPORT_SYMBOL(set_anon_super);
752
753void kill_anon_super(struct super_block *sb)
754{
755 int slot = MINOR(sb->s_dev);
756
757 generic_shutdown_super(sb);
758 spin_lock(&unnamed_dev_lock);
Alexey Dobriyanad76cbc2008-08-28 06:26:23 +0400759 ida_remove(&unnamed_dev_ida, slot);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 spin_unlock(&unnamed_dev_lock);
761}
762
763EXPORT_SYMBOL(kill_anon_super);
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765void kill_litter_super(struct super_block *sb)
766{
767 if (sb->s_root)
768 d_genocide(sb->s_root);
769 kill_anon_super(sb);
770}
771
772EXPORT_SYMBOL(kill_litter_super);
773
David Howells93614012006-09-30 20:45:40 +0200774#ifdef CONFIG_BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775static int set_bdev_super(struct super_block *s, void *data)
776{
777 s->s_bdev = data;
778 s->s_dev = s->s_bdev->bd_dev;
779 return 0;
780}
781
782static int test_bdev_super(struct super_block *s, void *data)
783{
784 return (void *)s->s_bdev == data;
785}
786
David Howells454e2392006-06-23 02:02:57 -0700787int get_sb_bdev(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 int flags, const char *dev_name, void *data,
David Howells454e2392006-06-23 02:02:57 -0700789 int (*fill_super)(struct super_block *, void *, int),
790 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791{
792 struct block_device *bdev;
793 struct super_block *s;
Al Viro30c40d22008-02-22 19:50:45 -0500794 fmode_t mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 int error = 0;
796
Al Viro30c40d22008-02-22 19:50:45 -0500797 if (!(flags & MS_RDONLY))
798 mode |= FMODE_WRITE;
799
800 bdev = open_bdev_exclusive(dev_name, mode, fs_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 if (IS_ERR(bdev))
David Howells454e2392006-06-23 02:02:57 -0700802 return PTR_ERR(bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803
804 /*
805 * once the super is inserted into the list by sget, s_umount
806 * will protect the lockfs code from trying to start a snapshot
807 * while we are mounting
808 */
David Chinnerf73ca1b2007-01-10 23:15:41 -0800809 down(&bdev->bd_mount_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
David Chinnerf73ca1b2007-01-10 23:15:41 -0800811 up(&bdev->bd_mount_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700813 goto error_s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814
815 if (s->s_root) {
816 if ((flags ^ s->s_flags) & MS_RDONLY) {
817 up_write(&s->s_umount);
818 deactivate_super(s);
David Howells454e2392006-06-23 02:02:57 -0700819 error = -EBUSY;
820 goto error_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 }
David Howells454e2392006-06-23 02:02:57 -0700822
Al Viro30c40d22008-02-22 19:50:45 -0500823 close_bdev_exclusive(bdev, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 } else {
825 char b[BDEVNAME_SIZE];
826
827 s->s_flags = flags;
Al Viro30c40d22008-02-22 19:50:45 -0500828 s->s_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
Pekka Enberge78c9a02006-01-08 01:03:39 -0800830 sb_set_blocksize(s, block_size(bdev));
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800831 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 if (error) {
833 up_write(&s->s_umount);
834 deactivate_super(s);
David Howells454e2392006-06-23 02:02:57 -0700835 goto error;
Greg Kroah-Hartmanfa675762006-02-22 09:39:02 -0800836 }
David Howells454e2392006-06-23 02:02:57 -0700837
838 s->s_flags |= MS_ACTIVE;
Theodore Ts'o87d8fe12009-01-03 09:47:09 -0500839 bdev->bd_super = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 }
841
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800842 simple_set_mnt(mnt, s);
843 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844
David Howells454e2392006-06-23 02:02:57 -0700845error_s:
846 error = PTR_ERR(s);
847error_bdev:
Al Viro30c40d22008-02-22 19:50:45 -0500848 close_bdev_exclusive(bdev, mode);
David Howells454e2392006-06-23 02:02:57 -0700849error:
850 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851}
852
853EXPORT_SYMBOL(get_sb_bdev);
854
855void kill_block_super(struct super_block *sb)
856{
857 struct block_device *bdev = sb->s_bdev;
Al Viro30c40d22008-02-22 19:50:45 -0500858 fmode_t mode = sb->s_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859
Theodore Ts'o87d8fe12009-01-03 09:47:09 -0500860 bdev->bd_super = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 generic_shutdown_super(sb);
862 sync_blockdev(bdev);
Al Viro30c40d22008-02-22 19:50:45 -0500863 close_bdev_exclusive(bdev, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864}
865
866EXPORT_SYMBOL(kill_block_super);
David Howells93614012006-09-30 20:45:40 +0200867#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
David Howells454e2392006-06-23 02:02:57 -0700869int get_sb_nodev(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 int flags, void *data,
David Howells454e2392006-06-23 02:02:57 -0700871 int (*fill_super)(struct super_block *, void *, int),
872 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873{
874 int error;
875 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
876
877 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700878 return PTR_ERR(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
880 s->s_flags = flags;
881
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800882 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 if (error) {
884 up_write(&s->s_umount);
885 deactivate_super(s);
David Howells454e2392006-06-23 02:02:57 -0700886 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 }
888 s->s_flags |= MS_ACTIVE;
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800889 simple_set_mnt(mnt, s);
890 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891}
892
893EXPORT_SYMBOL(get_sb_nodev);
894
895static int compare_single(struct super_block *s, void *p)
896{
897 return 1;
898}
899
David Howells454e2392006-06-23 02:02:57 -0700900int get_sb_single(struct file_system_type *fs_type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 int flags, void *data,
David Howells454e2392006-06-23 02:02:57 -0700902 int (*fill_super)(struct super_block *, void *, int),
903 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904{
905 struct super_block *s;
906 int error;
907
908 s = sget(fs_type, compare_single, set_anon_super, NULL);
909 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700910 return PTR_ERR(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 if (!s->s_root) {
912 s->s_flags = flags;
Theodore Ts'o9b04c992006-03-24 03:15:10 -0800913 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 if (error) {
915 up_write(&s->s_umount);
916 deactivate_super(s);
David Howells454e2392006-06-23 02:02:57 -0700917 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 }
919 s->s_flags |= MS_ACTIVE;
920 }
921 do_remount_sb(s, flags, data, 0);
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -0800922 simple_set_mnt(mnt, s);
923 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924}
925
926EXPORT_SYMBOL(get_sb_single);
927
928struct vfsmount *
Trond Myklebustbb4a58b2006-06-09 09:34:15 -0400929vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 struct vfsmount *mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 char *secdata = NULL;
David Howells454e2392006-06-23 02:02:57 -0700933 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
935 if (!type)
936 return ERR_PTR(-ENODEV);
937
David Howells454e2392006-06-23 02:02:57 -0700938 error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 mnt = alloc_vfsmnt(name);
940 if (!mnt)
941 goto out;
942
Eric Parise0007522008-03-05 10:31:54 -0500943 if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 secdata = alloc_secdata();
David Howells454e2392006-06-23 02:02:57 -0700945 if (!secdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 goto out_mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947
Eric Parise0007522008-03-05 10:31:54 -0500948 error = security_sb_copy_data(data, secdata);
David Howells454e2392006-06-23 02:02:57 -0700949 if (error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 goto out_free_secdata;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 }
952
David Howells454e2392006-06-23 02:02:57 -0700953 error = type->get_sb(type, flags, name, data, mnt);
954 if (error < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 goto out_free_secdata;
Lee Schermerhornb4c07bc2007-07-15 23:40:54 -0700956 BUG_ON(!mnt->mnt_sb);
David Howells454e2392006-06-23 02:02:57 -0700957
James Morris12204e22008-12-19 10:44:42 +1100958 error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 if (error)
960 goto out_sb;
David Howells454e2392006-06-23 02:02:57 -0700961
962 mnt->mnt_mountpoint = mnt->mnt_root;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 mnt->mnt_parent = mnt;
David Howells454e2392006-06-23 02:02:57 -0700964 up_write(&mnt->mnt_sb->s_umount);
Gerald Schaefer8680e222005-06-21 17:15:16 -0700965 free_secdata(secdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 return mnt;
967out_sb:
David Howells454e2392006-06-23 02:02:57 -0700968 dput(mnt->mnt_root);
969 up_write(&mnt->mnt_sb->s_umount);
970 deactivate_super(mnt->mnt_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971out_free_secdata:
972 free_secdata(secdata);
973out_mnt:
974 free_vfsmnt(mnt);
975out:
David Howells454e2392006-06-23 02:02:57 -0700976 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977}
978
Trond Myklebustbb4a58b2006-06-09 09:34:15 -0400979EXPORT_SYMBOL_GPL(vfs_kern_mount);
980
Miklos Szeredi79c0b2d2007-05-08 00:25:43 -0700981static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
982{
983 int err;
984 const char *subtype = strchr(fstype, '.');
985 if (subtype) {
986 subtype++;
987 err = -EINVAL;
988 if (!subtype[0])
989 goto err;
990 } else
991 subtype = "";
992
993 mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
994 err = -ENOMEM;
995 if (!mnt->mnt_sb->s_subtype)
996 goto err;
997 return mnt;
998
999 err:
1000 mntput(mnt);
1001 return ERR_PTR(err);
1002}
1003
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001004struct vfsmount *
1005do_kern_mount(const char *fstype, int flags, const char *name, void *data)
1006{
1007 struct file_system_type *type = get_fs_type(fstype);
1008 struct vfsmount *mnt;
1009 if (!type)
1010 return ERR_PTR(-ENODEV);
1011 mnt = vfs_kern_mount(type, flags, name, data);
Miklos Szeredi79c0b2d2007-05-08 00:25:43 -07001012 if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
1013 !mnt->mnt_sb->s_subtype)
1014 mnt = fs_set_subtype(mnt, fstype);
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001015 put_filesystem(type);
1016 return mnt;
1017}
Al Viro8a4e98d2008-02-24 01:43:03 -05001018EXPORT_SYMBOL_GPL(do_kern_mount);
Trond Myklebustbb4a58b2006-06-09 09:34:15 -04001019
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001020struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021{
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001022 return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023}
1024
Pavel Emelyanov8bf97252007-10-18 23:40:02 -07001025EXPORT_SYMBOL_GPL(kern_mount_data);