nixpkgs/nixos/modules/system/boot/stratisroot.nix

{ config, lib, pkgs, utils, ... }:
let
  requiredStratisFilesystems = lib.attrsets.filterAttrs (_: x: utils.fsNeededForBoot x && x.stratis.poolUuid != null) config.fileSystems;
in
{
  options = {};
  config = lib.mkIf (requiredStratisFilesystems != {}) {
    assertions = [
      {
        assertion = config.boot.initrd.systemd.enable;
        message = "stratis root fs requires systemd stage 1";
      }
    ];
    boot.initrd = {
      systemd = {
        storePaths = [
          "${pkgs.stratisd}/lib/udev/stratis-base32-decode"
          "${pkgs.stratisd}/lib/udev/stratis-str-cmp"
          "${pkgs.lvm2.bin}/bin/dmsetup"
          "${pkgs.stratisd}/libexec/stratisd-min"
          "${pkgs.stratisd.initrd}/bin/stratis-rootfs-setup"
        ];
        packages = [pkgs.stratisd.initrd];
        extraBin = {
          thin_check = "${pkgs."thin-provisioning-tools"}/bin/thin_check";
          thin_repair = "${pkgs."thin-provisioning-tools"}/bin/thin_repair";
          thin_metadata_size = "${pkgs."thin-provisioning-tools"}/bin/thin_metadata_size";
          stratis-min = "${pkgs.stratisd}/bin/stratis-min";
        };
        services =
          lib.attrsets.mapAttrs' (
            mountPoint: fileSystem: {
              name = "stratis-setup-${fileSystem.stratis.poolUuid}";
              value = {
                description = "setup for Stratis root filesystem";
                unitConfig.DefaultDependencies = "no";
                conflicts = [ "shutdown.target" "initrd-switch-root.target" ];
                onFailure = [ "emergency.target" ];
                unitConfig.OnFailureJobMode = "isolate";
                wants = [ "stratisd-min.service" "plymouth-start.service" ];
                wantedBy = [ "initrd.target" ];
                after = [ "paths.target" "plymouth-start.service" "stratisd-min.service" ];
                before = [ "initrd.target" "shutdown.target" "initrd-switch-root.target" ];
                environment.STRATIS_ROOTFS_UUID = fileSystem.stratis.poolUuid;
                serviceConfig = {
                  Type = "oneshot";
                  ExecStart = "${pkgs.stratisd.initrd}/bin/stratis-rootfs-setup";
                  RemainAfterExit = "yes";
                };
              };
            }
          ) requiredStratisFilesystems;
      };
      availableKernelModules = [ "dm-thin-pool" "dm-crypt" ] ++ [ "aes" "aes_generic" "blowfish" "twofish"
        "serpent" "cbc" "xts" "lrw" "sha1" "sha256" "sha512"
        "af_alg" "algif_skcipher"
      ];
      services.udev.packages = [
        pkgs.stratisd.initrd
        pkgs.lvm2
      ];
    };
  };
}