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Commit f73ca1b7 authored by David Chinner's avatar David Chinner Committed by Linus Torvalds
Browse files

[PATCH] Revert bd_mount_mutex back to a semaphore 



Revert bd_mount_mutex back to a semaphore so that xfs_freeze -f /mnt/newtest;
xfs_freeze -u /mnt/newtest works safely and doesn't produce lockdep warnings.

(XFS unlocks the semaphore from a different task, by design.  The mutex
code warns about this)

Signed-off-by: default avatarDave Chinner <dgc@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 88bf7b39

fs/block_dev.c

+1 −1
Original line number Diff line number Diff line
@@ -411,7 +411,7 @@ static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flag 
	{

		memset(bdev, 0, sizeof(*bdev));

		mutex_init(&bdev->bd_mutex);

		mutex_init(&bdev->bd_mount_mutex);

		sema_init(&bdev->bd_mount_sem, 1);

		INIT_LIST_HEAD(&bdev->bd_inodes);

		INIT_LIST_HEAD(&bdev->bd_list);

#ifdef CONFIG_SYSFS

fs/buffer.c

+3 −3
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ int fsync_bdev(struct block_device *bdev) 
 * freeze_bdev  --  lock a filesystem and force it into a consistent state

 * @bdev:	blockdevice to lock

 *

 * This takes the block device bd_mount_mutex to make sure no new mounts

 * This takes the block device bd_mount_sem to make sure no new mounts

 * happen on bdev until thaw_bdev() is called.

 * If a superblock is found on this device, we take the s_umount semaphore

 * on it to make sure nobody unmounts until the snapshot creation is done.
@@ -189,7 +189,7 @@ struct super_block *freeze_bdev(struct block_device *bdev) 
{

	struct super_block *sb;



	mutex_lock(&bdev->bd_mount_mutex);

	down(&bdev->bd_mount_sem);

	sb = get_super(bdev);

	if (sb && !(sb->s_flags & MS_RDONLY)) {

		sb->s_frozen = SB_FREEZE_WRITE;
@@ -231,7 +231,7 @@ void thaw_bdev(struct block_device *bdev, struct super_block *sb) 
		drop_super(sb);

	}



	mutex_unlock(&bdev->bd_mount_mutex);

	up(&bdev->bd_mount_sem);

}

EXPORT_SYMBOL(thaw_bdev);

fs/gfs2/ops_fstype.c

+2 −2
Original line number Diff line number Diff line
@@ -867,9 +867,9 @@ static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags, 
		error = -EBUSY;

		goto error;

	}

	mutex_lock(&sb->s_bdev->bd_mount_mutex);

	down(&sb->s_bdev->bd_mount_sem);

	new = sget(fs_type, test_bdev_super, set_bdev_super, sb->s_bdev);

	mutex_unlock(&sb->s_bdev->bd_mount_mutex);

	up(&sb->s_bdev->bd_mount_sem);

	if (IS_ERR(new)) {

		error = PTR_ERR(new);

		goto error;

fs/super.c

+2 −2
Original line number Diff line number Diff line
@@ -753,9 +753,9 @@ int get_sb_bdev(struct file_system_type *fs_type, 
	 * will protect the lockfs code from trying to start a snapshot

	 * while we are mounting

	 */

	mutex_lock(&bdev->bd_mount_mutex);

	down(&bdev->bd_mount_sem);

	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);

	mutex_unlock(&bdev->bd_mount_mutex);

	up(&bdev->bd_mount_sem);

	if (IS_ERR(s))

		goto error_s;

include/linux/fs.h

+1 −1
Original line number Diff line number Diff line
@@ -459,7 +459,7 @@ struct block_device { 
	struct inode *		bd_inode;	/* will die */

	int			bd_openers;

	struct mutex		bd_mutex;	/* open/close mutex */

	struct mutex		bd_mount_mutex;	/* mount mutex */

	struct semaphore	bd_mount_sem;

	struct list_head	bd_inodes;

	void *			bd_holder;

	int			bd_holders;