The patch titled
     Revert bd_mount_mutex back to a semaphore
has been removed from the -mm tree.  Its filename was
     revert-bd_mount_mutex-back-to-a-semaphore.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
Subject: Revert bd_mount_mutex back to a semaphore
From: David Chinner <[EMAIL PROTECTED]>

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]>
---

 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 [EMAIL PROTECTED] are

xfs-remove-useless-wmb-memory-barrier.patch
make-bh_unwritten-a-first-class-bufferhead-flag-v2.patch
make-xfs-use-bh_unwritten-and-bh_delay-correctly.patch

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