Convert to requeue_io_wait() for case:

	pages skipped due to locked buffers.

Cc: Michael Rubin <mrubin@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
 fs/fs-writeback.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

--- linux-mm.orig/fs/fs-writeback.c
+++ linux-mm/fs/fs-writeback.c
@@ -456,7 +456,7 @@ int generic_sync_sb_inodes(struct super_
 			 * writeback is not making progress due to locked
 			 * buffers.  Skip this inode for now.
 			 */
-			redirty_tail(inode);
+			requeue_io_wait(inode);
 		}
 		spin_unlock(&inode_lock);
 		iput(inode);
--