OP_LAYOUTGET
encode_op_hdr(xdr, OP_LAYOUTGET, decode_layoutget_maxsz, hdr);
status = decode_op_hdr(xdr, OP_LAYOUTGET);
[OP_LAYOUTGET] = {
[OP_LAYOUTGET] = nfsd4_decode_layoutget,
[OP_LAYOUTGET] = nfsd4_decode_notsupp,
[OP_LAYOUTGET] = nfsd4_encode_layoutget,
[OP_LAYOUTGET] = nfsd4_encode_noop,