The patch titled
Revert bd_mount_mutex back to a semaphore
has been added to the -mm tree. Its filename is
revert-bd_mount_mutex-back-to-a-semaphore.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Revert bd_mount_mutex back to a semaphore
From: David Chinner <dgc@xxxxxxx>
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@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/block_dev.c | 2 +-
fs/buffer.c | 6 +++---
fs/gfs2/ops_fstype.c | 4 ++--
fs/super.c | 4 ++--
include/linux/fs.h | 2 +-
5 files changed, 9 insertions(+), 9 deletions(-)
diff -puN fs/block_dev.c~revert-bd_mount_mutex-back-to-a-semaphore fs/block_dev.c
--- a/fs/block_dev.c~revert-bd_mount_mutex-back-to-a-semaphore
+++ a/fs/block_dev.c
@@ -411,7 +411,7 @@ static void init_once(void * foo, struct
{
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 -puN fs/buffer.c~revert-bd_mount_mutex-back-to-a-semaphore fs/buffer.c
--- a/fs/buffer.c~revert-bd_mount_mutex-back-to-a-semaphore
+++ a/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 b
{
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
drop_super(sb);
}
- mutex_unlock(&bdev->bd_mount_mutex);
+ up(&bdev->bd_mount_sem);
}
EXPORT_SYMBOL(thaw_bdev);
diff -puN fs/gfs2/ops_fstype.c~revert-bd_mount_mutex-back-to-a-semaphore fs/gfs2/ops_fstype.c
--- a/fs/gfs2/ops_fstype.c~revert-bd_mount_mutex-back-to-a-semaphore
+++ a/fs/gfs2/ops_fstype.c
@@ -867,9 +867,9 @@ static int gfs2_get_sb_meta(struct file_
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 -puN fs/super.c~revert-bd_mount_mutex-back-to-a-semaphore fs/super.c
--- a/fs/super.c~revert-bd_mount_mutex-back-to-a-semaphore
+++ a/fs/super.c
@@ -753,9 +753,9 @@ int get_sb_bdev(struct file_system_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 -puN include/linux/fs.h~revert-bd_mount_mutex-back-to-a-semaphore include/linux/fs.h
--- a/include/linux/fs.h~revert-bd_mount_mutex-back-to-a-semaphore
+++ a/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;
_
Patches currently in -mm which might be from dgc@xxxxxxx are
revert-bd_mount_mutex-back-to-a-semaphore.patch
xfs-remove-useless-wmb-memory-barrier.patch
-
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