[PATCH 3.2 014/152] drbd: merge_bvec_fn: properly remap bvm->bi_bdev

Ben Hutchings
2015-02-17T01:46:53Z

From: Lars Ellenberg <lars.ellenberg@linbit.com>

commit 3b9d35d744bb5139f9fed57f38c019bb8c7d351c upstream.

This was not noticed for many years. Affects operation if
md raid is used a backing device for DRBD.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
[bwh: Backported to 3.2: s/device/mdev/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/block/drbd/drbd_req.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1184,6 +1184,7 @@ int drbd_merge_bvec(struct request_queue
struct request_queue * const b =
mdev->ldev->backing_bdev->bd_disk->queue;
if (b->merge_bvec_fn) {
+ bvm->bi_bdev = mdev->ldev->backing_bdev;
backing_limit = b->merge_bvec_fn(b, bvm, bvec);
limit = min(limit, backing_limit);
}