[PATCH] rbd: fix image request leak on parent read

[Alex Elder <elder@inktank.com>]

When a read for a layered image object finds the target object
doesn't exist, a read image request for the parent image is created
and submitted.  When that completes, the callback routine was
not releasing that parent image request.  Fix that.

The slab allocation stuff just added has greatly simplified the
search for the source of this memory leak.

This resolves:
    http://tracker.ceph.com/issues/4803

Signed-off-by: Alex Elder <elder@inktank.com>
---
 drivers/block/rbd.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 8d9aeef..d669f71 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2547,6 +2547,7 @@ static void rbd_img_parent_read_callback(struct
rbd_img_request *img_request)
 		obj_request->xferred = img_request->xferred;
 	}
 out:
+	rbd_img_request_put(img_request);
 	rbd_img_obj_request_read_callback(obj_request);
 	rbd_obj_request_complete(obj_request);
 }
-- 
1.7.9.5