reiserfs: Don't call reiserfs_get_acl() with the reiserfs lock

reiserfs_get_acl is usually not called under the reiserfs lock,
as it doesn't need it. But it happens when it is called by
reiserfs_acl_chmod(), which creates a dependency inversion against
the private xattr inodes mutexes for the given inode.

We need to call it without the reiserfs lock, especially since
it's unnecessary.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>

fs/reiserfs/xattr_acl.c

@@ -452,7 +452,9 @@ int reiserfs_acl_chmod(struct inode *inode)
 		return 0;
 	}
 
+	reiserfs_write_unlock(inode->i_sb);
 	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
+	reiserfs_write_lock(inode->i_sb);
 	if (!acl)
 		return 0;
 	if (IS_ERR(acl))