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

[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
......@@ -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
......
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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;
......
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