From: Jens Axboe <jaxboe@fusionio.com>
Date: Fri, 25 Mar 2011 15:57:52 +0000 (+0100)
Subject: block: fix bug with inserting flush requests as sort/merge
X-Git-Tag: v3.12-rc1~6531^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=401a18e92ce32cd0ddfa5738899ca2b8114f2bbf;p=kernel%2Fkernel-generic.git

block: fix bug with inserting flush requests as sort/merge

With the introduction of the on-stack plugging, we would assume
that any request being inserted was a normal file system request.
As flush/fua requires a special insert mode, this caused problems.

Fix this up by checking for this in flush_plug_list() and use
the appropriate insert mechanism.

Big thanks goes to Markus Tripplesdorf for tirelessly testing
patches, and to Sergey Senozhatsky for helping find the real
issue.

Reported-by: Markus Tripplesdorf <markus@trippelsdorf.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---

diff --git a/block/blk-core.c b/block/blk-core.c
index 59b5c00..64e96ee 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2702,7 +2702,10 @@ static void flush_plug_list(struct blk_plug *plug)
 		/*
 		 * rq is already accounted, so use raw insert
 		 */
-		__elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
+		if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA))
+			__elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);
+		else
+			__elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
 	}
 
 	if (q) {