drbd_set_role
extern enum drbd_state_rv drbd_set_role(struct drbd_device *device,
retcode = drbd_set_role(peer_device->device, R_SECONDARY, 0);
rv = drbd_set_role(adm_ctx->device, R_PRIMARY, parms.assume_uptodate);
rv = drbd_set_role(adm_ctx->device, R_SECONDARY, 0);