repart: Enable discard option (#397906)

        example = "require";

        default = "refuse";

      };

      discard = lib.mkOption {

        type = lib.types.bool;

        description = ''

          Controls whether to issue the BLKDISCARD I/O control command on the

          space taken up by any added partitions or on the space in between them.

          Usually, it's a good idea to issue this request since it tells the underlying

          hardware that the covered blocks shall be considered empty, improving performance.

          See {manpage}`systemd-repart(8)` for details.

        '';

        default = true;

      };

    };

    systemd.repart = {

                                  --definitions=/etc/repart.d \

                                  --dry-run=no \

                                  --empty=${initrdCfg.empty} \

                                  --discard=${lib.boolToString initrdCfg.discard} \

                                  ${lib.optionalString (initrdCfg.device != null) initrdCfg.device}

              ''

            ];