hpfs_hpbmap
int hpfs_hpbmap (struct hpfsnode *, daddr_t, daddr_t *, int *);
error = hpfs_hpbmap (hp, lbn, &dbn, ap->a_runp);
error = hpfs_hpbmap(hp, lbn, &bn, &runl);
error = hpfs_hpbmap(hp, lbn, &bn, &runl);