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>
36 LIST_HEAD(super_blocks);
37 DEFINE_SPINLOCK(sb_lock);
40 * alloc_super - create new superblock
41 * @type: filesystem type superblock should belong to
43 * Allocates and initializes a new &struct super_block. alloc_super()
44 * returns a pointer new superblock or %NULL if allocation had failed.
46 static struct super_block *alloc_super(struct file_system_type *type)
48 struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
49 static const struct super_operations default_op;
52 if (security_sb_alloc(s)) {
57 INIT_LIST_HEAD(&s->s_files);
58 INIT_LIST_HEAD(&s->s_instances);
59 INIT_HLIST_HEAD(&s->s_anon);
60 INIT_LIST_HEAD(&s->s_inodes);
61 INIT_LIST_HEAD(&s->s_dentry_lru);
62 init_rwsem(&s->s_umount);
63 mutex_init(&s->s_lock);
64 lockdep_set_class(&s->s_umount, &type->s_umount_key);
66 * The locking rules for s_lock are up to the
67 * filesystem. For example ext3fs has different
68 * lock ordering than usbfs:
70 lockdep_set_class(&s->s_lock, &type->s_lock_key);
72 * sget() can have s_umount recursion.
74 * When it cannot find a suitable sb, it allocates a new
75 * one (this one), and tries again to find a suitable old
78 * In case that succeeds, it will acquire the s_umount
79 * lock of the old one. Since these are clearly distrinct
80 * locks, and this object isn't exposed yet, there's no
83 * Annotate this by putting this lock in a different
86 down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
88 atomic_set(&s->s_active, 1);
89 mutex_init(&s->s_vfs_rename_mutex);
90 lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
91 mutex_init(&s->s_dquot.dqio_mutex);
92 mutex_init(&s->s_dquot.dqonoff_mutex);
93 init_rwsem(&s->s_dquot.dqptr_sem);
94 init_waitqueue_head(&s->s_wait_unfrozen);
95 s->s_maxbytes = MAX_NON_LFS;
96 s->s_op = &default_op;
97 s->s_time_gran = 1000000000;
104 * destroy_super - frees a superblock
105 * @s: superblock to free
107 * Frees a superblock.
109 static inline void destroy_super(struct super_block *s)
117 /* Superblock refcounting */
120 * Drop a superblock's refcount. The caller must hold sb_lock.
122 void __put_super(struct super_block *sb)
124 if (!--sb->s_count) {
125 list_del_init(&sb->s_list);
131 * put_super - drop a temporary reference to superblock
132 * @sb: superblock in question
134 * Drops a temporary reference, frees superblock if there's no
137 void put_super(struct super_block *sb)
141 spin_unlock(&sb_lock);
146 * deactivate_locked_super - drop an active reference to superblock
147 * @s: superblock to deactivate
149 * Drops an active reference to superblock, converting it into a temprory
150 * one if there is no other active references left. In that case we
151 * tell fs driver to shut it down and drop the temporary reference we
154 * Caller holds exclusive lock on superblock; that lock is released.
156 void deactivate_locked_super(struct super_block *s)
158 struct file_system_type *fs = s->s_type;
159 if (atomic_dec_and_test(&s->s_active)) {
164 up_write(&s->s_umount);
168 EXPORT_SYMBOL(deactivate_locked_super);
171 * deactivate_super - drop an active reference to superblock
172 * @s: superblock to deactivate
174 * Variant of deactivate_locked_super(), except that superblock is *not*
175 * locked by caller. If we are going to drop the final active reference,
176 * lock will be acquired prior to that.
178 void deactivate_super(struct super_block *s)
180 if (!atomic_add_unless(&s->s_active, -1, 1)) {
181 down_write(&s->s_umount);
182 deactivate_locked_super(s);
186 EXPORT_SYMBOL(deactivate_super);
189 * grab_super - acquire an active reference
190 * @s: reference we are trying to make active
192 * Tries to acquire an active reference. grab_super() is used when we
193 * had just found a superblock in super_blocks or fs_type->fs_supers
194 * and want to turn it into a full-blown active reference. grab_super()
195 * is called with sb_lock held and drops it. Returns 1 in case of
196 * success, 0 if we had failed (superblock contents was already dead or
197 * dying when grab_super() had been called).
199 static int grab_super(struct super_block *s) __releases(sb_lock)
201 if (atomic_inc_not_zero(&s->s_active)) {
202 spin_unlock(&sb_lock);
205 /* it's going away */
207 spin_unlock(&sb_lock);
208 /* wait for it to die */
209 down_write(&s->s_umount);
210 up_write(&s->s_umount);
216 * Superblock locking. We really ought to get rid of these two.
218 void lock_super(struct super_block * sb)
221 mutex_lock(&sb->s_lock);
224 void unlock_super(struct super_block * sb)
227 mutex_unlock(&sb->s_lock);
230 EXPORT_SYMBOL(lock_super);
231 EXPORT_SYMBOL(unlock_super);
234 * generic_shutdown_super - common helper for ->kill_sb()
235 * @sb: superblock to kill
237 * generic_shutdown_super() does all fs-independent work on superblock
238 * shutdown. Typical ->kill_sb() should pick all fs-specific objects
239 * that need destruction out of superblock, call generic_shutdown_super()
240 * and release aforementioned objects. Note: dentries and inodes _are_
241 * taken care of and do not need specific handling.
243 * Upon calling this function, the filesystem may no longer alter or
244 * rearrange the set of dentries belonging to this super_block, nor may it
245 * change the attachments of dentries to inodes.
247 void generic_shutdown_super(struct super_block *sb)
249 const struct super_operations *sop = sb->s_op;
253 shrink_dcache_for_umount(sb);
256 sb->s_flags &= ~MS_ACTIVE;
258 /* bad name - it should be evict_inodes() */
259 invalidate_inodes(sb);
264 /* Forget any remaining inodes */
265 if (invalidate_inodes(sb)) {
266 printk("VFS: Busy inodes after unmount of %s. "
267 "Self-destruct in 5 seconds. Have a nice day...\n",
273 /* should be initialized for __put_super_and_need_restart() */
274 list_del_init(&sb->s_instances);
275 spin_unlock(&sb_lock);
276 up_write(&sb->s_umount);
279 EXPORT_SYMBOL(generic_shutdown_super);
282 * sget - find or create a superblock
283 * @type: filesystem type superblock should belong to
284 * @test: comparison callback
285 * @set: setup callback
286 * @data: argument to each of them
288 struct super_block *sget(struct file_system_type *type,
289 int (*test)(struct super_block *,void *),
290 int (*set)(struct super_block *,void *),
293 struct super_block *s = NULL;
294 struct super_block *old;
300 list_for_each_entry(old, &type->fs_supers, s_instances) {
301 if (!test(old, data))
303 if (!grab_super(old))
306 up_write(&s->s_umount);
309 down_write(&old->s_umount);
314 spin_unlock(&sb_lock);
315 s = alloc_super(type);
317 return ERR_PTR(-ENOMEM);
323 spin_unlock(&sb_lock);
324 up_write(&s->s_umount);
329 strlcpy(s->s_id, type->name, sizeof(s->s_id));
330 list_add_tail(&s->s_list, &super_blocks);
331 list_add(&s->s_instances, &type->fs_supers);
332 spin_unlock(&sb_lock);
333 get_filesystem(type);
339 void drop_super(struct super_block *sb)
341 up_read(&sb->s_umount);
345 EXPORT_SYMBOL(drop_super);
348 * sync_supers - helper for periodic superblock writeback
350 * Call the write_super method if present on all dirty superblocks in
351 * the system. This is for the periodic writeback used by most older
352 * filesystems. For data integrity superblock writeback use
353 * sync_filesystems() instead.
355 * Note: check the dirty flag before waiting, so we don't
356 * hold up the sync while mounting a device. (The newly
357 * mounted device won't need syncing.)
359 void sync_supers(void)
361 struct super_block *sb, *n;
364 list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
365 if (list_empty(&sb->s_instances))
367 if (sb->s_op->write_super && sb->s_dirt) {
369 spin_unlock(&sb_lock);
371 down_read(&sb->s_umount);
372 if (sb->s_root && sb->s_dirt)
373 sb->s_op->write_super(sb);
374 up_read(&sb->s_umount);
380 spin_unlock(&sb_lock);
384 * iterate_supers - call function for all active superblocks
385 * @f: function to call
386 * @arg: argument to pass to it
388 * Scans the superblock list and calls given function, passing it
389 * locked superblock and given argument.
391 void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
393 struct super_block *sb, *n;
396 list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
397 if (list_empty(&sb->s_instances))
400 spin_unlock(&sb_lock);
402 down_read(&sb->s_umount);
405 up_read(&sb->s_umount);
410 spin_unlock(&sb_lock);
414 * get_super - get the superblock of a device
415 * @bdev: device to get the superblock for
417 * Scans the superblock list and finds the superblock of the file system
418 * mounted on the device given. %NULL is returned if no match is found.
421 struct super_block *get_super(struct block_device *bdev)
423 struct super_block *sb;
430 list_for_each_entry(sb, &super_blocks, s_list) {
431 if (list_empty(&sb->s_instances))
433 if (sb->s_bdev == bdev) {
435 spin_unlock(&sb_lock);
436 down_read(&sb->s_umount);
440 up_read(&sb->s_umount);
441 /* nope, got unmounted */
447 spin_unlock(&sb_lock);
451 EXPORT_SYMBOL(get_super);
454 * get_active_super - get an active reference to the superblock of a device
455 * @bdev: device to get the superblock for
457 * Scans the superblock list and finds the superblock of the file system
458 * mounted on the device given. Returns the superblock with an active
459 * reference or %NULL if none was found.
461 struct super_block *get_active_super(struct block_device *bdev)
463 struct super_block *sb;
470 list_for_each_entry(sb, &super_blocks, s_list) {
471 if (list_empty(&sb->s_instances))
473 if (sb->s_bdev == bdev) {
474 if (grab_super(sb)) /* drops sb_lock */
480 spin_unlock(&sb_lock);
484 struct super_block *user_get_super(dev_t dev)
486 struct super_block *sb;
490 list_for_each_entry(sb, &super_blocks, s_list) {
491 if (list_empty(&sb->s_instances))
493 if (sb->s_dev == dev) {
495 spin_unlock(&sb_lock);
496 down_read(&sb->s_umount);
500 up_read(&sb->s_umount);
501 /* nope, got unmounted */
507 spin_unlock(&sb_lock);
511 #define REMOUNT_FORCE 1
512 #define REMOUNT_SHRINK_DCACHE 2
514 static int __do_remount_sb(struct super_block *sb, int flags, void *data, int rflags)
519 if (sb->s_frozen != SB_UNFROZEN)
523 if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
527 if (flags & MS_RDONLY)
529 if (rflags & REMOUNT_SHRINK_DCACHE)
530 shrink_dcache_sb(sb);
533 remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
535 /* If we are remounting RDONLY and current sb is read/write,
536 make sure there are no rw files opened */
538 if (rflags & REMOUNT_FORCE)
540 else if (!fs_may_remount_ro(sb))
544 if (sb->s_op->remount_fs) {
545 retval = sb->s_op->remount_fs(sb, &flags, data);
549 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
552 * Some filesystems modify their metadata via some other path than the
553 * bdev buffer cache (eg. use a private mapping, or directories in
554 * pagecache, etc). Also file data modifications go via their own
555 * mappings. So If we try to mount readonly then copy the filesystem
556 * from bdev, we could get stale data, so invalidate it to give a best
557 * effort at coherency.
559 if (remount_ro && sb->s_bdev)
560 invalidate_bdev(sb->s_bdev);
565 * do_remount_sb - asks filesystem to change mount options.
566 * @sb: superblock in question
567 * @flags: numeric part of options
568 * @data: the rest of options
569 * @force: whether or not to force the change
571 * Alters the mount options of a mounted file system.
573 int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
575 return __do_remount_sb(sb, flags, data,
576 REMOUNT_SHRINK_DCACHE|(force? REMOUNT_FORCE : 0));
579 static void do_emergency_remount(struct work_struct *work)
581 struct super_block *sb, *n;
584 list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
585 if (list_empty(&sb->s_instances))
588 spin_unlock(&sb_lock);
589 down_write(&sb->s_umount);
590 if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
592 * What lock protects sb->s_flags??
594 do_remount_sb(sb, MS_RDONLY, NULL, 1);
596 up_write(&sb->s_umount);
600 spin_unlock(&sb_lock);
602 printk("Emergency Remount complete\n");
605 void emergency_remount(void)
607 struct work_struct *work;
609 work = kmalloc(sizeof(*work), GFP_ATOMIC);
611 INIT_WORK(work, do_emergency_remount);
617 * Unnamed block devices are dummy devices used by virtual
618 * filesystems which don't use real block-devices. -- jrs
621 static DEFINE_IDA(unnamed_dev_ida);
622 static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
623 static int unnamed_dev_start = 0; /* don't bother trying below it */
625 int set_anon_super(struct super_block *s, void *data)
631 if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
633 spin_lock(&unnamed_dev_lock);
634 error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
636 unnamed_dev_start = dev + 1;
637 spin_unlock(&unnamed_dev_lock);
638 if (error == -EAGAIN)
639 /* We raced and lost with another CPU. */
644 if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
645 spin_lock(&unnamed_dev_lock);
646 ida_remove(&unnamed_dev_ida, dev);
647 if (unnamed_dev_start > dev)
648 unnamed_dev_start = dev;
649 spin_unlock(&unnamed_dev_lock);
652 s->s_dev = MKDEV(0, dev & MINORMASK);
653 s->s_bdi = &noop_backing_dev_info;
657 EXPORT_SYMBOL(set_anon_super);
659 void kill_anon_super(struct super_block *sb)
661 int slot = MINOR(sb->s_dev);
663 generic_shutdown_super(sb);
664 spin_lock(&unnamed_dev_lock);
665 ida_remove(&unnamed_dev_ida, slot);
666 if (slot < unnamed_dev_start)
667 unnamed_dev_start = slot;
668 spin_unlock(&unnamed_dev_lock);
671 EXPORT_SYMBOL(kill_anon_super);
673 void kill_litter_super(struct super_block *sb)
676 d_genocide(sb->s_root);
680 EXPORT_SYMBOL(kill_litter_super);
682 static int ns_test_super(struct super_block *sb, void *data)
684 return sb->s_fs_info == data;
687 static int ns_set_super(struct super_block *sb, void *data)
689 sb->s_fs_info = data;
690 return set_anon_super(sb, NULL);
693 int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
694 int (*fill_super)(struct super_block *, void *, int),
695 struct vfsmount *mnt)
697 struct super_block *sb;
699 sb = sget(fs_type, ns_test_super, ns_set_super, data);
706 err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
708 deactivate_locked_super(sb);
712 sb->s_flags |= MS_ACTIVE;
715 simple_set_mnt(mnt, sb);
719 EXPORT_SYMBOL(get_sb_ns);
722 static int set_bdev_super(struct super_block *s, void *data)
725 s->s_dev = s->s_bdev->bd_dev;
728 * We set the bdi here to the queue backing, file systems can
729 * overwrite this in ->fill_super()
731 s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
735 static int test_bdev_super(struct super_block *s, void *data)
737 return (void *)s->s_bdev == data;
740 int get_sb_bdev(struct file_system_type *fs_type,
741 int flags, const char *dev_name, void *data,
742 int (*fill_super)(struct super_block *, void *, int),
743 struct vfsmount *mnt)
745 struct block_device *bdev;
746 struct super_block *s;
747 fmode_t mode = FMODE_READ;
750 if (!(flags & MS_RDONLY))
753 bdev = open_bdev_exclusive(dev_name, mode, fs_type);
755 return PTR_ERR(bdev);
758 * once the super is inserted into the list by sget, s_umount
759 * will protect the lockfs code from trying to start a snapshot
760 * while we are mounting
762 mutex_lock(&bdev->bd_fsfreeze_mutex);
763 if (bdev->bd_fsfreeze_count > 0) {
764 mutex_unlock(&bdev->bd_fsfreeze_mutex);
768 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
769 mutex_unlock(&bdev->bd_fsfreeze_mutex);
774 if ((flags ^ s->s_flags) & MS_RDONLY) {
775 deactivate_locked_super(s);
780 close_bdev_exclusive(bdev, mode);
782 char b[BDEVNAME_SIZE];
786 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
787 sb_set_blocksize(s, block_size(bdev));
788 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
790 deactivate_locked_super(s);
794 s->s_flags |= MS_ACTIVE;
798 simple_set_mnt(mnt, s);
804 close_bdev_exclusive(bdev, mode);
809 EXPORT_SYMBOL(get_sb_bdev);
811 void kill_block_super(struct super_block *sb)
813 struct block_device *bdev = sb->s_bdev;
814 fmode_t mode = sb->s_mode;
816 bdev->bd_super = NULL;
817 generic_shutdown_super(sb);
819 close_bdev_exclusive(bdev, mode);
822 EXPORT_SYMBOL(kill_block_super);
825 int get_sb_nodev(struct file_system_type *fs_type,
826 int flags, void *data,
827 int (*fill_super)(struct super_block *, void *, int),
828 struct vfsmount *mnt)
831 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
838 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
840 deactivate_locked_super(s);
843 s->s_flags |= MS_ACTIVE;
844 simple_set_mnt(mnt, s);
848 EXPORT_SYMBOL(get_sb_nodev);
850 static int compare_single(struct super_block *s, void *p)
855 int get_sb_single(struct file_system_type *fs_type,
856 int flags, void *data,
857 int (*fill_super)(struct super_block *, void *, int),
858 struct vfsmount *mnt)
860 struct super_block *s;
863 s = sget(fs_type, compare_single, set_anon_super, NULL);
868 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
870 deactivate_locked_super(s);
873 s->s_flags |= MS_ACTIVE;
875 __do_remount_sb(s, flags, data, 0);
877 simple_set_mnt(mnt, s);
881 EXPORT_SYMBOL(get_sb_single);
884 vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
886 struct vfsmount *mnt;
887 char *secdata = NULL;
891 return ERR_PTR(-ENODEV);
894 mnt = alloc_vfsmnt(name);
898 if (flags & MS_KERNMOUNT)
899 mnt->mnt_flags = MNT_INTERNAL;
901 if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
902 secdata = alloc_secdata();
906 error = security_sb_copy_data(data, secdata);
908 goto out_free_secdata;
911 error = type->get_sb(type, flags, name, data, mnt);
913 goto out_free_secdata;
914 BUG_ON(!mnt->mnt_sb);
915 WARN_ON(!mnt->mnt_sb->s_bdi);
917 error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
922 * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
923 * but s_maxbytes was an unsigned long long for many releases. Throw
924 * this warning for a little while to try and catch filesystems that
925 * violate this rule. This warning should be either removed or
926 * converted to a BUG() in 2.6.34.
928 WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
929 "negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
931 mnt->mnt_mountpoint = mnt->mnt_root;
932 mnt->mnt_parent = mnt;
933 up_write(&mnt->mnt_sb->s_umount);
934 free_secdata(secdata);
938 deactivate_locked_super(mnt->mnt_sb);
940 free_secdata(secdata);
944 return ERR_PTR(error);
947 EXPORT_SYMBOL_GPL(vfs_kern_mount);
950 * freeze_super - lock the filesystem and force it into a consistent state
951 * @sb: the super to lock
953 * Syncs the super to make sure the filesystem is consistent and calls the fs's
954 * freeze_fs. Subsequent calls to this without first thawing the fs will return
957 int freeze_super(struct super_block *sb)
961 atomic_inc(&sb->s_active);
962 down_write(&sb->s_umount);
964 deactivate_locked_super(sb);
968 if (sb->s_flags & MS_RDONLY) {
969 sb->s_frozen = SB_FREEZE_TRANS;
971 up_write(&sb->s_umount);
975 sb->s_frozen = SB_FREEZE_WRITE;
980 sb->s_frozen = SB_FREEZE_TRANS;
983 sync_blockdev(sb->s_bdev);
984 if (sb->s_op->freeze_fs) {
985 ret = sb->s_op->freeze_fs(sb);
988 "VFS:Filesystem freeze failed\n");
989 sb->s_frozen = SB_UNFROZEN;
990 deactivate_locked_super(sb);
994 up_write(&sb->s_umount);
997 EXPORT_SYMBOL(freeze_super);
1000 * thaw_super -- unlock filesystem
1001 * @sb: the super to thaw
1003 * Unlocks the filesystem and marks it writeable again after freeze_super().
1005 int thaw_super(struct super_block *sb)
1009 down_write(&sb->s_umount);
1010 if (sb->s_frozen == SB_UNFROZEN) {
1011 up_write(&sb->s_umount);
1015 if (sb->s_flags & MS_RDONLY)
1018 if (sb->s_op->unfreeze_fs) {
1019 error = sb->s_op->unfreeze_fs(sb);
1022 "VFS:Filesystem thaw failed\n");
1023 sb->s_frozen = SB_FREEZE_TRANS;
1024 up_write(&sb->s_umount);
1030 sb->s_frozen = SB_UNFROZEN;
1032 wake_up(&sb->s_wait_unfrozen);
1033 deactivate_locked_super(sb);
1037 EXPORT_SYMBOL(thaw_super);
1039 static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
1042 const char *subtype = strchr(fstype, '.');
1051 mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
1053 if (!mnt->mnt_sb->s_subtype)
1059 return ERR_PTR(err);
1063 do_kern_mount(const char *fstype, int flags, const char *name, void *data)
1065 struct file_system_type *type = get_fs_type(fstype);
1066 struct vfsmount *mnt;
1068 return ERR_PTR(-ENODEV);
1069 mnt = vfs_kern_mount(type, flags, name, data);
1070 if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
1071 !mnt->mnt_sb->s_subtype)
1072 mnt = fs_set_subtype(mnt, fstype);
1073 put_filesystem(type);
1076 EXPORT_SYMBOL_GPL(do_kern_mount);
1078 struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
1080 return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
1083 EXPORT_SYMBOL_GPL(kern_mount_data);