pc_bmap
error = pc_bmap(pcp, pc_lblkno(fsp, offset), &bn, NULL);
err1 = pc_bmap(pcp, lbn, &bn, &xfersize);
err1 = pc_bmap(pcp, (daddr_t)lbn, &bn, &xfersize);
extern int pc_bmap(struct pcnode *, daddr_t, daddr_t *, uint_t *);