rbd: don't put snap_context twice in rbd_queue_workfn()

Commit 4e752f0ab0e8 ("rbd: access snapshot context and mapping size
safely") moved ceph_get_snap_context() out of rbd_img_request_create()
and into rbd_queue_workfn(), adding a ceph_put_snap_context() to the
error path in rbd_queue_workfn().  However, rbd_img_request_create()
consumes a ref on snapc, so calling ceph_put_snap_context() after
a successful rbd_img_request_create() leads to an extra put.  Fix it.

Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 235708c7c46eee709acb110acb95a28d85ebc946..81ea69fee7ca183313b8e8322833062262279187 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3442,6 +3442,7 @@ static void rbd_queue_workfn(struct work_struct *work)
                goto err_rq;
        }
        img_request->rq = rq;
+       snapc = NULL; /* img_request consumes a ref */
 
        if (op_type == OBJ_OP_DISCARD)
                result = rbd_img_request_fill(img_request, OBJ_REQUEST_NODATA,