fh3_xdata
bcopy(bp, fhp->fh3_xdata, dsize);
bcopy(fh.fh3_xdata, &buf[i], fh.fh3_xlen);
bcopy(fh.fh3_xdata, &logbuf[i], sz);
ASSERT(fh->fh3_xlen <= sizeof (fh->fh3_xdata));
bcopy(exi->exi_fid.fid_data, fh->fh3_xdata, fh->fh3_xlen);