hpfs_addextentr
error = hpfs_addextentr (hpmp, anp->an_lsn, &al, ranp, &pf);
int hpfs_addextentr (struct hpfsmount *, lsn_t, alleaf_t *,
error = hpfs_addextentr (hpmp, anp->an_lsn, ralp, ranp, &pf);