cbtocylno
cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
cg_blktot(&acg)[cbtocylno(&sblock, d)]++;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
cg_blktot(&acg)[cbtocylno(&sblock, d)]--;
cg_blks(&sblock, &acg, cbtocylno(&sblock, d))
cylno = cbtocylno(fs, bno);
i = cbtocylno(fs, bno);
i = cbtocylno(fs, bbase);