nixos/global/fs/xfs.nix

{ lib
, config
, ... }: with lib; let
  cfg = config.global.fs;
in mkIf (cfg.type == "xfs") {
  # NOTE: -m reflink=1
  fileSystems."/nix" =
  { device = "/dev/disk/by-uuid/${cfg.store}";
    fsType = "xfs";
  };
}