[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: Dave Chinner <[email protected]> Cc: Ingo Molnar <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ambv · Jan 12, 2007 · f73ca1b · f73ca1b
1 parent 88bf7b3
commit f73ca1b
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Showing 5 changed files with 9 additions and 9 deletions.
diff --git a/fs/block_dev.c b/fs/block_dev.c
@@ -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

diff --git a/fs/buffer.c b/fs/buffer.c
@@ -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);
 

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
@@ -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;

diff --git a/fs/super.c b/fs/super.c
@@ -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;
 

diff --git a/include/linux/fs.h b/include/linux/fs.h
@@ -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;