osd_req_op_cls_init
ret = osd_req_op_cls_init(req, which, "rbd", "object_map_update");
ret = osd_req_op_cls_init(osd_req, which, "rbd", "copyup");
int osd_req_op_cls_init(struct ceph_osd_request *osd_req, unsigned int which,
ret = osd_req_op_cls_init(req, which, "lock", "assert_locked");
ret = osd_req_op_cls_init(req, 0, class, method);
EXPORT_SYMBOL(osd_req_op_cls_init);