---

yaml --- r: 123291 b: refs/heads/master c: a185eb4 h: refs/heads/master i: 123289: 2fdb69d 123287: 43b5b18 v: v3
git-mirror · Dec 29, 2008 · 1f97be2 · 1f97be2
1 parent c4d2a3e
commit 1f97be2
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 58eea927d2de43dc6f03d1ba2c46e55854b31540
+refs/heads/master: a185eb4bc84155fff35b602ce99602c010de9634
diff --git a/trunk/block/blk-barrier.c b/trunk/block/blk-barrier.c
@@ -166,9 +166,21 @@ static inline bool start_ordered(struct request_queue *q, struct request **rqp)
 	 * For an empty barrier, there's no actual BAR request, which
 	 * in turn makes POSTFLUSH unnecessary.  Mask them off.
 	 */
-	if (!rq->hard_nr_sectors)
+	if (!rq->hard_nr_sectors) {
 		q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
 				QUEUE_ORDERED_DO_POSTFLUSH);
+		/*
+		 * Empty barrier on a write-through device w/ ordered
+		 * tag has no command to issue and without any command
+		 * to issue, ordering by tag can't be used.  Drain
+		 * instead.
+		 */
+		if ((q->ordered & QUEUE_ORDERED_BY_TAG) &&
+		    !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) {
+			q->ordered &= ~QUEUE_ORDERED_BY_TAG;
+			q->ordered |= QUEUE_ORDERED_BY_DRAIN;
+		}
+	}
 
 	/* stash away the original request */
 	elv_dequeue_request(q, rq);