cg_old_ncyl
int16_t cg_old_ncyl; /* number of cyl's this cg */
n->cg_old_ncyl = bswap16(o->cg_old_ncyl);
acg.cg_old_ncyl = howmany(acg.cg_ndblk,
acg.cg_old_ncyl = sblock.fs_old_cpg;