OP_GETDEVICEINFO
encode_op_hdr(xdr, OP_GETDEVICEINFO, decode_getdeviceinfo_maxsz, hdr);
status = decode_op_hdr(xdr, OP_GETDEVICEINFO);
[OP_GETDEVICEINFO] = {
[OP_GETDEVICEINFO] = nfsd4_decode_getdeviceinfo,
[OP_GETDEVICEINFO] = nfsd4_decode_notsupp,
[OP_GETDEVICEINFO] = nfsd4_encode_getdeviceinfo,
[OP_GETDEVICEINFO] = nfsd4_encode_noop,