[ 065/136 ] MD: ignore discard request for hard disks of hybid raid1/raid10array

[Steven Rostedt]

3.6.11.4 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Shaohua Li <shli@xxxxxxxxxx>

[ Upstream commit 32f9f570d04461a41bdcd5c1d93b41ebc5ce182a ]

In SSD/hard disk hybid storage, discard request should be ignored for hard
disk. We used to be doing this way, but the unplug path forgets it.

This is suitable for stable tree since v3.6.

Cc: stable@xxxxxxxxxxxxxxx
Reported-and-tested-by: Markus <M4rkusXXL@xxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 drivers/md/raid1.c  |    7 ++++++-
 drivers/md/raid10.c |    6 ++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 7077dcf..36c6003 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -976,7 +976,12 @@ static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
 	while (bio) { /* submit pending writes */
 		struct bio *next = bio->bi_next;
 		bio->bi_next = NULL;
-		generic_make_request(bio);
+		if (unlikely((bio->bi_rw & REQ_DISCARD) &&
+		    !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
+			/* Just ignore it */
+			bio_endio(bio, 0);
+		else
+			generic_make_request(bio);
 		bio = next;
 	}
 	kfree(plug);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c52d893..bec9db8 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -912,6 +912,12 @@ static void flush_pending_writes(struct r10conf *conf)
 			struct bio *next = bio->bi_next;
 			bio->bi_next = NULL;
 			generic_make_request(bio);
+			if (unlikely((bio->bi_rw & REQ_DISCARD) &&
+				     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
+				/* Just ignore it */
+				bio_endio(bio, 0);
+			else
+				generic_make_request(bio);
 			bio = next;
 		}
 	} else
-- 
1.7.10.4


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