chkrange
if (chkrange(idesc->id_blkno, idesc->id_numfrags)) {
int chkrange(daddr32_t, int);
if (chkrange(idesc->id_blkno, idesc->id_numfrags)) {
if ((anyout = chkrange(fragno, idesc->id_numfrags)) != 0) {
if (anyout && chkrange(fragno, 1)) {
if (chkrange(blkno, 1)) {
if (chkrange(blkno + fragnum, 1)) {