From cc763bcbb0bcc75b5926a30d2135be47e63e6895 Mon Sep 17 00:00:00 2001
From: Tejun Heo <htejun@gmail.com>
Date: Fri, 15 Jun 2007 13:24:28 +0200
Subject: [PATCH] --- yaml --- r: 57775 b: refs/heads/master c:
 bc90ba093af2e5022b9d055a2148b54a6aa35bc9 h: refs/heads/master i:   57773:
 1f09a41dc67b93b084be152d672a8e17b3de0176   57771:
 ff0ae662b063239530ec44f437700870f8049632   57767:
 cb4d3b0c70910e35f0ad2e116344bac396bb761c   57759:
 327de45ffc9df6db9b042c3f6f5756fdac66bf1a v: v3

---
 [refs]                  | 2 +-
 trunk/block/ll_rw_blk.c | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 66bf4ee214fe..d2aa040161fd 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e126c7b6bbb0c5b5fc3ecf2fd1ae67c803b747cc
+refs/heads/master: bc90ba093af2e5022b9d055a2148b54a6aa35bc9
diff --git a/trunk/block/ll_rw_blk.c b/trunk/block/ll_rw_blk.c
index 6b5173ac8131..c99b46354859 100644
--- a/trunk/block/ll_rw_blk.c
+++ b/trunk/block/ll_rw_blk.c
@@ -340,6 +340,15 @@ unsigned blk_ordered_req_seq(struct request *rq)
 	if (rq == &q->post_flush_rq)
 		return QUEUE_ORDSEQ_POSTFLUSH;
 
+	/*
+	 * !fs requests don't need to follow barrier ordering.  Always
+	 * put them at the front.  This fixes the following deadlock.
+	 *
+	 * http://thread.gmane.org/gmane.linux.kernel/537473
+	 */
+	if (!blk_fs_request(rq))
+		return QUEUE_ORDSEQ_DRAIN;
+
 	if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
 	    (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
 		return QUEUE_ORDSEQ_DRAIN;