[PATCH] raid0: Set discard_granularity to correct value after reshape.

[Pawel Baldysiak <pawel.baldysiak@intel.com>]

In case of reshape of raid0 through raid4 a value of discard_granularity
will be set to stripe size. MD driver should re-set this value to correct
one when migration will be finished. Otherwise array will be left with
wrong value and discard operations will not work properly.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Cc: Shaohua Li <shli@kernel.org>
---
 drivers/md/raid0.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index c4d420b..807ca3a 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -266,6 +266,8 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 	}
 	mddev->queue->backing_dev_info.congested_fn = raid0_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
+	mddev->queue->limits.discard_granularity =
+			queue_logical_block_size(mddev->queue);
 
 	/*
 	 * now since we have the hard sector sizes, we can make sure