RBX_CTL
if (flags & RBX_CTL) {
rctlsys_rblk_xfrm(nblk, krde, nval, RBX_TO_BLK | RBX_VAL | RBX_CTL);
if (flags & RBX_CTL) {
rctlsys_rblk_xfrm(krblk, krde, NULL, RBX_TO_BLK | RBX_CTL);
rctlsys_rblk_xfrm(krblk, krde, NULL, RBX_FROM_BLK | RBX_CTL);