OP_READDIR
encode_op_hdr(xdr, OP_READDIR, decode_readdir_maxsz, hdr);
trace_nfs4_xdr_bad_filehandle(xdr, OP_READDIR,
status = decode_op_hdr(xdr, OP_READDIR);
[OP_READDIR] = {
[OP_READDIR] = nfsd4_decode_readdir,
[OP_READDIR] = nfsd4_encode_readdir,