4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * super.c contains code to handle: - mount structures
8 * - filesystem drivers list
10 * - umount system call
13 * GK 2/5/95 - Changed to support mounting the root fs via NFS
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
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/acct.h>
26 #include <linux/blkdev.h>
27 #include <linux/mount.h>
28 #include <linux/security.h>
29 #include <linux/writeback.h> /* for the emergency remount stuff */
30 #include <linux/idr.h>
31 #include <linux/mutex.h>
32 #include <linux/backing-dev.h>
33 #include <linux/rculist_bl.h>
34 #include <linux/cleancache.h>
38 LIST_HEAD(super_blocks
);
39 DEFINE_SPINLOCK(sb_lock
);
42 * alloc_super - create new superblock
43 * @type: filesystem type superblock should belong to
45 * Allocates and initializes a new &struct super_block. alloc_super()
46 * returns a pointer new superblock or %NULL if allocation had failed.
48 static struct super_block
*alloc_super(struct file_system_type
*type
)
50 struct super_block
*s
= kzalloc(sizeof(struct super_block
), GFP_USER
);
51 static const struct super_operations default_op
;
54 if (security_sb_alloc(s
)) {
60 s
->s_files
= alloc_percpu(struct list_head
);
69 for_each_possible_cpu(i
)
70 INIT_LIST_HEAD(per_cpu_ptr(s
->s_files
, i
));
73 INIT_LIST_HEAD(&s
->s_files
);
75 s
->s_bdi
= &default_backing_dev_info
;
76 INIT_LIST_HEAD(&s
->s_instances
);
77 INIT_HLIST_BL_HEAD(&s
->s_anon
);
78 INIT_LIST_HEAD(&s
->s_inodes
);
79 INIT_LIST_HEAD(&s
->s_dentry_lru
);
80 INIT_LIST_HEAD(&s
->s_inode_lru
);
81 init_rwsem(&s
->s_umount
);
82 mutex_init(&s
->s_lock
);
83 lockdep_set_class(&s
->s_umount
, &type
->s_umount_key
);
85 * The locking rules for s_lock are up to the
86 * filesystem. For example ext3fs has different
87 * lock ordering than usbfs:
89 lockdep_set_class(&s
->s_lock
, &type
->s_lock_key
);
91 * sget() can have s_umount recursion.
93 * When it cannot find a suitable sb, it allocates a new
94 * one (this one), and tries again to find a suitable old
97 * In case that succeeds, it will acquire the s_umount
98 * lock of the old one. Since these are clearly distrinct
99 * locks, and this object isn't exposed yet, there's no
102 * Annotate this by putting this lock in a different
105 down_write_nested(&s
->s_umount
, SINGLE_DEPTH_NESTING
);
107 atomic_set(&s
->s_active
, 1);
108 mutex_init(&s
->s_vfs_rename_mutex
);
109 lockdep_set_class(&s
->s_vfs_rename_mutex
, &type
->s_vfs_rename_key
);
110 mutex_init(&s
->s_dquot
.dqio_mutex
);
111 mutex_init(&s
->s_dquot
.dqonoff_mutex
);
112 init_rwsem(&s
->s_dquot
.dqptr_sem
);
113 init_waitqueue_head(&s
->s_wait_unfrozen
);
114 s
->s_maxbytes
= MAX_NON_LFS
;
115 s
->s_op
= &default_op
;
116 s
->s_time_gran
= 1000000000;
117 s
->cleancache_poolid
= -1;
124 * destroy_super - frees a superblock
125 * @s: superblock to free
127 * Frees a superblock.
129 static inline void destroy_super(struct super_block
*s
)
132 free_percpu(s
->s_files
);
140 /* Superblock refcounting */
143 * Drop a superblock's refcount. The caller must hold sb_lock.
145 void __put_super(struct super_block
*sb
)
147 if (!--sb
->s_count
) {
148 list_del_init(&sb
->s_list
);
154 * put_super - drop a temporary reference to superblock
155 * @sb: superblock in question
157 * Drops a temporary reference, frees superblock if there's no
160 void put_super(struct super_block
*sb
)
164 spin_unlock(&sb_lock
);
169 * deactivate_locked_super - drop an active reference to superblock
170 * @s: superblock to deactivate
172 * Drops an active reference to superblock, converting it into a temprory
173 * one if there is no other active references left. In that case we
174 * tell fs driver to shut it down and drop the temporary reference we
177 * Caller holds exclusive lock on superblock; that lock is released.
179 void deactivate_locked_super(struct super_block
*s
)
181 struct file_system_type
*fs
= s
->s_type
;
182 if (atomic_dec_and_test(&s
->s_active
)) {
183 cleancache_flush_fs(s
);
186 * We need to call rcu_barrier so all the delayed rcu free
187 * inodes are flushed before we release the fs module.
193 up_write(&s
->s_umount
);
197 EXPORT_SYMBOL(deactivate_locked_super
);
200 * deactivate_super - drop an active reference to superblock
201 * @s: superblock to deactivate
203 * Variant of deactivate_locked_super(), except that superblock is *not*
204 * locked by caller. If we are going to drop the final active reference,
205 * lock will be acquired prior to that.
207 void deactivate_super(struct super_block
*s
)
209 if (!atomic_add_unless(&s
->s_active
, -1, 1)) {
210 down_write(&s
->s_umount
);
211 deactivate_locked_super(s
);
215 EXPORT_SYMBOL(deactivate_super
);
218 * grab_super - acquire an active reference
219 * @s: reference we are trying to make active
221 * Tries to acquire an active reference. grab_super() is used when we
222 * had just found a superblock in super_blocks or fs_type->fs_supers
223 * and want to turn it into a full-blown active reference. grab_super()
224 * is called with sb_lock held and drops it. Returns 1 in case of
225 * success, 0 if we had failed (superblock contents was already dead or
226 * dying when grab_super() had been called).
228 static int grab_super(struct super_block
*s
) __releases(sb_lock
)
230 if (atomic_inc_not_zero(&s
->s_active
)) {
231 spin_unlock(&sb_lock
);
234 /* it's going away */
236 spin_unlock(&sb_lock
);
237 /* wait for it to die */
238 down_write(&s
->s_umount
);
239 up_write(&s
->s_umount
);
245 * Superblock locking. We really ought to get rid of these two.
247 void lock_super(struct super_block
* sb
)
250 mutex_lock(&sb
->s_lock
);
253 void unlock_super(struct super_block
* sb
)
256 mutex_unlock(&sb
->s_lock
);
259 EXPORT_SYMBOL(lock_super
);
260 EXPORT_SYMBOL(unlock_super
);
263 * generic_shutdown_super - common helper for ->kill_sb()
264 * @sb: superblock to kill
266 * generic_shutdown_super() does all fs-independent work on superblock
267 * shutdown. Typical ->kill_sb() should pick all fs-specific objects
268 * that need destruction out of superblock, call generic_shutdown_super()
269 * and release aforementioned objects. Note: dentries and inodes _are_
270 * taken care of and do not need specific handling.
272 * Upon calling this function, the filesystem may no longer alter or
273 * rearrange the set of dentries belonging to this super_block, nor may it
274 * change the attachments of dentries to inodes.
276 void generic_shutdown_super(struct super_block
*sb
)
278 const struct super_operations
*sop
= sb
->s_op
;
282 shrink_dcache_for_umount(sb
);
285 sb
->s_flags
&= ~MS_ACTIVE
;
287 fsnotify_unmount_inodes(&sb
->s_inodes
);
294 if (!list_empty(&sb
->s_inodes
)) {
295 printk("VFS: Busy inodes after unmount of %s. "
296 "Self-destruct in 5 seconds. Have a nice day...\n",
302 /* should be initialized for __put_super_and_need_restart() */
303 list_del_init(&sb
->s_instances
);
304 spin_unlock(&sb_lock
);
305 up_write(&sb
->s_umount
);
308 EXPORT_SYMBOL(generic_shutdown_super
);
311 * sget - find or create a superblock
312 * @type: filesystem type superblock should belong to
313 * @test: comparison callback
314 * @set: setup callback
315 * @data: argument to each of them
317 struct super_block
*sget(struct file_system_type
*type
,
318 int (*test
)(struct super_block
*,void *),
319 int (*set
)(struct super_block
*,void *),
322 struct super_block
*s
= NULL
;
323 struct super_block
*old
;
329 list_for_each_entry(old
, &type
->fs_supers
, s_instances
) {
330 if (!test(old
, data
))
332 if (!grab_super(old
))
335 up_write(&s
->s_umount
);
339 down_write(&old
->s_umount
);
340 if (unlikely(!(old
->s_flags
& MS_BORN
))) {
341 deactivate_locked_super(old
);
348 spin_unlock(&sb_lock
);
349 s
= alloc_super(type
);
351 return ERR_PTR(-ENOMEM
);
357 spin_unlock(&sb_lock
);
358 up_write(&s
->s_umount
);
363 strlcpy(s
->s_id
, type
->name
, sizeof(s
->s_id
));
364 list_add_tail(&s
->s_list
, &super_blocks
);
365 list_add(&s
->s_instances
, &type
->fs_supers
);
366 spin_unlock(&sb_lock
);
367 get_filesystem(type
);
373 void drop_super(struct super_block
*sb
)
375 up_read(&sb
->s_umount
);
379 EXPORT_SYMBOL(drop_super
);
382 * sync_supers - helper for periodic superblock writeback
384 * Call the write_super method if present on all dirty superblocks in
385 * the system. This is for the periodic writeback used by most older
386 * filesystems. For data integrity superblock writeback use
387 * sync_filesystems() instead.
389 * Note: check the dirty flag before waiting, so we don't
390 * hold up the sync while mounting a device. (The newly
391 * mounted device won't need syncing.)
393 void sync_supers(void)
395 struct super_block
*sb
, *p
= NULL
;
398 list_for_each_entry(sb
, &super_blocks
, s_list
) {
399 if (list_empty(&sb
->s_instances
))
401 if (sb
->s_op
->write_super
&& sb
->s_dirt
) {
403 spin_unlock(&sb_lock
);
405 down_read(&sb
->s_umount
);
406 if (sb
->s_root
&& sb
->s_dirt
)
407 sb
->s_op
->write_super(sb
);
408 up_read(&sb
->s_umount
);
418 spin_unlock(&sb_lock
);
422 * iterate_supers - call function for all active superblocks
423 * @f: function to call
424 * @arg: argument to pass to it
426 * Scans the superblock list and calls given function, passing it
427 * locked superblock and given argument.
429 void iterate_supers(void (*f
)(struct super_block
*, void *), void *arg
)
431 struct super_block
*sb
, *p
= NULL
;
434 list_for_each_entry(sb
, &super_blocks
, s_list
) {
435 if (list_empty(&sb
->s_instances
))
438 spin_unlock(&sb_lock
);
440 down_read(&sb
->s_umount
);
443 up_read(&sb
->s_umount
);
452 spin_unlock(&sb_lock
);
456 * iterate_supers_type - call function for superblocks of given type
458 * @f: function to call
459 * @arg: argument to pass to it
461 * Scans the superblock list and calls given function, passing it
462 * locked superblock and given argument.
464 void iterate_supers_type(struct file_system_type
*type
,
465 void (*f
)(struct super_block
*, void *), void *arg
)
467 struct super_block
*sb
, *p
= NULL
;
470 list_for_each_entry(sb
, &type
->fs_supers
, s_instances
) {
472 spin_unlock(&sb_lock
);
474 down_read(&sb
->s_umount
);
477 up_read(&sb
->s_umount
);
486 spin_unlock(&sb_lock
);
489 EXPORT_SYMBOL(iterate_supers_type
);
492 * get_super - get the superblock of a device
493 * @bdev: device to get the superblock for
495 * Scans the superblock list and finds the superblock of the file system
496 * mounted on the device given. %NULL is returned if no match is found.
499 struct super_block
*get_super(struct block_device
*bdev
)
501 struct super_block
*sb
;
508 list_for_each_entry(sb
, &super_blocks
, s_list
) {
509 if (list_empty(&sb
->s_instances
))
511 if (sb
->s_bdev
== bdev
) {
513 spin_unlock(&sb_lock
);
514 down_read(&sb
->s_umount
);
518 up_read(&sb
->s_umount
);
519 /* nope, got unmounted */
525 spin_unlock(&sb_lock
);
529 EXPORT_SYMBOL(get_super
);
532 * get_active_super - get an active reference to the superblock of a device
533 * @bdev: device to get the superblock for
535 * Scans the superblock list and finds the superblock of the file system
536 * mounted on the device given. Returns the superblock with an active
537 * reference or %NULL if none was found.
539 struct super_block
*get_active_super(struct block_device
*bdev
)
541 struct super_block
*sb
;
548 list_for_each_entry(sb
, &super_blocks
, s_list
) {
549 if (list_empty(&sb
->s_instances
))
551 if (sb
->s_bdev
== bdev
) {
552 if (grab_super(sb
)) /* drops sb_lock */
558 spin_unlock(&sb_lock
);
562 struct super_block
*user_get_super(dev_t dev
)
564 struct super_block
*sb
;
568 list_for_each_entry(sb
, &super_blocks
, s_list
) {
569 if (list_empty(&sb
->s_instances
))
571 if (sb
->s_dev
== dev
) {
573 spin_unlock(&sb_lock
);
574 down_read(&sb
->s_umount
);
578 up_read(&sb
->s_umount
);
579 /* nope, got unmounted */
585 spin_unlock(&sb_lock
);
590 * do_remount_sb - asks filesystem to change mount options.
591 * @sb: superblock in question
592 * @flags: numeric part of options
593 * @data: the rest of options
594 * @force: whether or not to force the change
596 * Alters the mount options of a mounted file system.
598 int do_remount_sb(struct super_block
*sb
, int flags
, void *data
, int force
)
603 if (sb
->s_frozen
!= SB_UNFROZEN
)
607 if (!(flags
& MS_RDONLY
) && bdev_read_only(sb
->s_bdev
))
611 if (flags
& MS_RDONLY
)
613 shrink_dcache_sb(sb
);
616 remount_ro
= (flags
& MS_RDONLY
) && !(sb
->s_flags
& MS_RDONLY
);
618 /* If we are remounting RDONLY and current sb is read/write,
619 make sure there are no rw files opened */
623 else if (!fs_may_remount_ro(sb
))
627 if (sb
->s_op
->remount_fs
) {
628 retval
= sb
->s_op
->remount_fs(sb
, &flags
, data
);
632 sb
->s_flags
= (sb
->s_flags
& ~MS_RMT_MASK
) | (flags
& MS_RMT_MASK
);
635 * Some filesystems modify their metadata via some other path than the
636 * bdev buffer cache (eg. use a private mapping, or directories in
637 * pagecache, etc). Also file data modifications go via their own
638 * mappings. So If we try to mount readonly then copy the filesystem
639 * from bdev, we could get stale data, so invalidate it to give a best
640 * effort at coherency.
642 if (remount_ro
&& sb
->s_bdev
)
643 invalidate_bdev(sb
->s_bdev
);
647 static void do_emergency_remount(struct work_struct
*work
)
649 struct super_block
*sb
, *p
= NULL
;
652 list_for_each_entry(sb
, &super_blocks
, s_list
) {
653 if (list_empty(&sb
->s_instances
))
656 spin_unlock(&sb_lock
);
657 down_write(&sb
->s_umount
);
658 if (sb
->s_root
&& sb
->s_bdev
&& !(sb
->s_flags
& MS_RDONLY
)) {
660 * What lock protects sb->s_flags??
662 do_remount_sb(sb
, MS_RDONLY
, NULL
, 1);
664 up_write(&sb
->s_umount
);
672 spin_unlock(&sb_lock
);
674 printk("Emergency Remount complete\n");
677 void emergency_remount(void)
679 struct work_struct
*work
;
681 work
= kmalloc(sizeof(*work
), GFP_ATOMIC
);
683 INIT_WORK(work
, do_emergency_remount
);
689 * Unnamed block devices are dummy devices used by virtual
690 * filesystems which don't use real block-devices. -- jrs
693 static DEFINE_IDA(unnamed_dev_ida
);
694 static DEFINE_SPINLOCK(unnamed_dev_lock
);/* protects the above */
695 static int unnamed_dev_start
= 0; /* don't bother trying below it */
697 int get_anon_bdev(dev_t
*p
)
703 if (ida_pre_get(&unnamed_dev_ida
, GFP_ATOMIC
) == 0)
705 spin_lock(&unnamed_dev_lock
);
706 error
= ida_get_new_above(&unnamed_dev_ida
, unnamed_dev_start
, &dev
);
708 unnamed_dev_start
= dev
+ 1;
709 spin_unlock(&unnamed_dev_lock
);
710 if (error
== -EAGAIN
)
711 /* We raced and lost with another CPU. */
716 if ((dev
& MAX_ID_MASK
) == (1 << MINORBITS
)) {
717 spin_lock(&unnamed_dev_lock
);
718 ida_remove(&unnamed_dev_ida
, dev
);
719 if (unnamed_dev_start
> dev
)
720 unnamed_dev_start
= dev
;
721 spin_unlock(&unnamed_dev_lock
);
724 *p
= MKDEV(0, dev
& MINORMASK
);
727 EXPORT_SYMBOL(get_anon_bdev
);
729 void free_anon_bdev(dev_t dev
)
731 int slot
= MINOR(dev
);
732 spin_lock(&unnamed_dev_lock
);
733 ida_remove(&unnamed_dev_ida
, slot
);
734 if (slot
< unnamed_dev_start
)
735 unnamed_dev_start
= slot
;
736 spin_unlock(&unnamed_dev_lock
);
738 EXPORT_SYMBOL(free_anon_bdev
);
740 int set_anon_super(struct super_block
*s
, void *data
)
742 int error
= get_anon_bdev(&s
->s_dev
);
744 s
->s_bdi
= &noop_backing_dev_info
;
748 EXPORT_SYMBOL(set_anon_super
);
750 void kill_anon_super(struct super_block
*sb
)
752 dev_t dev
= sb
->s_dev
;
753 generic_shutdown_super(sb
);
757 EXPORT_SYMBOL(kill_anon_super
);
759 void kill_litter_super(struct super_block
*sb
)
762 d_genocide(sb
->s_root
);
766 EXPORT_SYMBOL(kill_litter_super
);
768 static int ns_test_super(struct super_block
*sb
, void *data
)
770 return sb
->s_fs_info
== data
;
773 static int ns_set_super(struct super_block
*sb
, void *data
)
775 sb
->s_fs_info
= data
;
776 return set_anon_super(sb
, NULL
);
779 struct dentry
*mount_ns(struct file_system_type
*fs_type
, int flags
,
780 void *data
, int (*fill_super
)(struct super_block
*, void *, int))
782 struct super_block
*sb
;
784 sb
= sget(fs_type
, ns_test_super
, ns_set_super
, data
);
791 err
= fill_super(sb
, data
, flags
& MS_SILENT
? 1 : 0);
793 deactivate_locked_super(sb
);
797 sb
->s_flags
|= MS_ACTIVE
;
800 return dget(sb
->s_root
);
803 EXPORT_SYMBOL(mount_ns
);
806 static int set_bdev_super(struct super_block
*s
, void *data
)
809 s
->s_dev
= s
->s_bdev
->bd_dev
;
812 * We set the bdi here to the queue backing, file systems can
813 * overwrite this in ->fill_super()
815 s
->s_bdi
= &bdev_get_queue(s
->s_bdev
)->backing_dev_info
;
819 static int test_bdev_super(struct super_block
*s
, void *data
)
821 return (void *)s
->s_bdev
== data
;
824 struct dentry
*mount_bdev(struct file_system_type
*fs_type
,
825 int flags
, const char *dev_name
, void *data
,
826 int (*fill_super
)(struct super_block
*, void *, int))
828 struct block_device
*bdev
;
829 struct super_block
*s
;
830 fmode_t mode
= FMODE_READ
| FMODE_EXCL
;
833 if (!(flags
& MS_RDONLY
))
836 bdev
= blkdev_get_by_path(dev_name
, mode
, fs_type
);
838 return ERR_CAST(bdev
);
841 * once the super is inserted into the list by sget, s_umount
842 * will protect the lockfs code from trying to start a snapshot
843 * while we are mounting
845 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
846 if (bdev
->bd_fsfreeze_count
> 0) {
847 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
851 s
= sget(fs_type
, test_bdev_super
, set_bdev_super
, bdev
);
852 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
857 if ((flags
^ s
->s_flags
) & MS_RDONLY
) {
858 deactivate_locked_super(s
);
864 * s_umount nests inside bd_mutex during
865 * __invalidate_device(). blkdev_put() acquires
866 * bd_mutex and can't be called under s_umount. Drop
867 * s_umount temporarily. This is safe as we're
868 * holding an active reference.
870 up_write(&s
->s_umount
);
871 blkdev_put(bdev
, mode
);
872 down_write(&s
->s_umount
);
874 char b
[BDEVNAME_SIZE
];
876 s
->s_flags
= flags
| MS_NOSEC
;
878 strlcpy(s
->s_id
, bdevname(bdev
, b
), sizeof(s
->s_id
));
879 sb_set_blocksize(s
, block_size(bdev
));
880 error
= fill_super(s
, data
, flags
& MS_SILENT
? 1 : 0);
882 deactivate_locked_super(s
);
886 s
->s_flags
|= MS_ACTIVE
;
890 return dget(s
->s_root
);
895 blkdev_put(bdev
, mode
);
897 return ERR_PTR(error
);
899 EXPORT_SYMBOL(mount_bdev
);
901 void kill_block_super(struct super_block
*sb
)
903 struct block_device
*bdev
= sb
->s_bdev
;
904 fmode_t mode
= sb
->s_mode
;
906 bdev
->bd_super
= NULL
;
907 generic_shutdown_super(sb
);
909 WARN_ON_ONCE(!(mode
& FMODE_EXCL
));
910 blkdev_put(bdev
, mode
| FMODE_EXCL
);
913 EXPORT_SYMBOL(kill_block_super
);
916 struct dentry
*mount_nodev(struct file_system_type
*fs_type
,
917 int flags
, void *data
,
918 int (*fill_super
)(struct super_block
*, void *, int))
921 struct super_block
*s
= sget(fs_type
, NULL
, set_anon_super
, NULL
);
928 error
= fill_super(s
, data
, flags
& MS_SILENT
? 1 : 0);
930 deactivate_locked_super(s
);
931 return ERR_PTR(error
);
933 s
->s_flags
|= MS_ACTIVE
;
934 return dget(s
->s_root
);
936 EXPORT_SYMBOL(mount_nodev
);
938 static int compare_single(struct super_block
*s
, void *p
)
943 struct dentry
*mount_single(struct file_system_type
*fs_type
,
944 int flags
, void *data
,
945 int (*fill_super
)(struct super_block
*, void *, int))
947 struct super_block
*s
;
950 s
= sget(fs_type
, compare_single
, set_anon_super
, NULL
);
955 error
= fill_super(s
, data
, flags
& MS_SILENT
? 1 : 0);
957 deactivate_locked_super(s
);
958 return ERR_PTR(error
);
960 s
->s_flags
|= MS_ACTIVE
;
962 do_remount_sb(s
, flags
, data
, 0);
964 return dget(s
->s_root
);
966 EXPORT_SYMBOL(mount_single
);
969 mount_fs(struct file_system_type
*type
, int flags
, const char *name
, void *data
)
972 struct super_block
*sb
;
973 char *secdata
= NULL
;
976 if (data
&& !(type
->fs_flags
& FS_BINARY_MOUNTDATA
)) {
977 secdata
= alloc_secdata();
981 error
= security_sb_copy_data(data
, secdata
);
983 goto out_free_secdata
;
986 root
= type
->mount(type
, flags
, name
, data
);
988 error
= PTR_ERR(root
);
989 goto out_free_secdata
;
994 WARN_ON(sb
->s_bdi
== &default_backing_dev_info
);
995 sb
->s_flags
|= MS_BORN
;
997 error
= security_sb_kern_mount(sb
, flags
, secdata
);
1002 * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
1003 * but s_maxbytes was an unsigned long long for many releases. Throw
1004 * this warning for a little while to try and catch filesystems that
1005 * violate this rule.
1007 WARN((sb
->s_maxbytes
< 0), "%s set sb->s_maxbytes to "
1008 "negative value (%lld)\n", type
->name
, sb
->s_maxbytes
);
1010 up_write(&sb
->s_umount
);
1011 free_secdata(secdata
);
1015 deactivate_locked_super(sb
);
1017 free_secdata(secdata
);
1019 return ERR_PTR(error
);
1023 * freeze_super - lock the filesystem and force it into a consistent state
1024 * @sb: the super to lock
1026 * Syncs the super to make sure the filesystem is consistent and calls the fs's
1027 * freeze_fs. Subsequent calls to this without first thawing the fs will return
1030 int freeze_super(struct super_block
*sb
)
1034 atomic_inc(&sb
->s_active
);
1035 down_write(&sb
->s_umount
);
1037 deactivate_locked_super(sb
);
1041 if (sb
->s_flags
& MS_RDONLY
) {
1042 sb
->s_frozen
= SB_FREEZE_TRANS
;
1044 up_write(&sb
->s_umount
);
1048 sb
->s_frozen
= SB_FREEZE_WRITE
;
1051 sync_filesystem(sb
);
1053 sb
->s_frozen
= SB_FREEZE_TRANS
;
1056 sync_blockdev(sb
->s_bdev
);
1057 if (sb
->s_op
->freeze_fs
) {
1058 ret
= sb
->s_op
->freeze_fs(sb
);
1061 "VFS:Filesystem freeze failed\n");
1062 sb
->s_frozen
= SB_UNFROZEN
;
1063 deactivate_locked_super(sb
);
1067 up_write(&sb
->s_umount
);
1070 EXPORT_SYMBOL(freeze_super
);
1073 * thaw_super -- unlock filesystem
1074 * @sb: the super to thaw
1076 * Unlocks the filesystem and marks it writeable again after freeze_super().
1078 int thaw_super(struct super_block
*sb
)
1082 down_write(&sb
->s_umount
);
1083 if (sb
->s_frozen
== SB_UNFROZEN
) {
1084 up_write(&sb
->s_umount
);
1088 if (sb
->s_flags
& MS_RDONLY
)
1091 if (sb
->s_op
->unfreeze_fs
) {
1092 error
= sb
->s_op
->unfreeze_fs(sb
);
1095 "VFS:Filesystem thaw failed\n");
1096 sb
->s_frozen
= SB_FREEZE_TRANS
;
1097 up_write(&sb
->s_umount
);
1103 sb
->s_frozen
= SB_UNFROZEN
;
1105 wake_up(&sb
->s_wait_unfrozen
);
1106 deactivate_locked_super(sb
);
1110 EXPORT_SYMBOL(thaw_super
);