libceph: support for alloc hint flags

Allow indicating future I/O pattern via flags.  This is supported since
Kraken (and bluestore persists flags together with expected_object_size
and expected_write_size).

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 67d65ac..97e102e 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2253,7 +2253,8 @@ static void __rbd_osd_setup_write_ops(struct ceph_osd_request *osd_req,
 	    !(obj_req->flags & RBD_OBJ_FLAG_MAY_EXIST)) {
 		osd_req_op_alloc_hint_init(osd_req, which++,
 					   rbd_dev->layout.object_size,
-					   rbd_dev->layout.object_size);
+					   rbd_dev->layout.object_size,
+					   0);
 	}
 
 	if (rbd_obj_is_entire(obj_req))