[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 <dgc@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1715d6b..8b18e43 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -411,7 +411,7 @@
{
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
index 263f88e..3b11607 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -180,7 +180,7 @@
* 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 *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 @@
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
index d14e139..ee80b8a 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -867,9 +867,9 @@
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
index f961e03..3e7458c 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -753,9 +753,9 @@
* 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
index 14a337c..1410e53 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -459,7 +459,7 @@
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;