(untested) config for stinky and diff script.

common/impermanence.nix

@@ -1,6 +1,5 @@
 {
   pkgs,
-  inputs,
   lib,
   config,
   ...
@@ -9,31 +8,22 @@ let
   cfg = config.custom.impermanence;
 in
 {
+  # Import common impermanence configuration
+  imports = [ ./impermanence-common.nix ];
+
   options.custom.impermanence = {
     enable = lib.mkOption {
       type = lib.types.bool;
       default = true;
-      description = "Enable impermanent root fs";
+      description = "Enable impermanent root fs with btrfs subvolume rollback";
     };
   };
 
   config = lib.mkIf cfg.enable {
-    environment.persistence = {
-      "/persist" = {
-        directories = [
-          "/var/lib/nixos"
-          "/home"
-        ];
-        files = [
-          "/etc/machine-id"
-          "/etc/ssh/ssh_host_ed25519_key"
-          "/etc/ssh/ssh_host_ed25519_key.pub"
-          "/etc/ssh/ssh_host_rsa_key"
-          "/etc/ssh/ssh_host_rsa_key.pub"
-        ];
-      };
-    };
+    # Use /persist for btrfs-based impermanence
+    custom.impermanence.persistPath = "/persist";
 
+    # Btrfs-specific filesystem options
     fileSystems."/".options = [
       "compress=zstd"
       "noatime"
@@ -53,17 +43,7 @@ in
     ];
     fileSystems."/var/log".neededForBoot = true;
 
-    users.mutableUsers = false;
-
-    # rollback results in sudo lectures after each reboot
-    security.sudo.extraConfig = ''
-      Defaults lecture = never
-    '';
-
-    # needed for allowOther in the home-manager impermanence config
-    programs.fuse.userAllowOther = true;
-
-    # reset / at each boot
+    # Btrfs subvolume rollback at each boot
     # Note `lib.mkBefore` is used instead of `lib.mkAfter` here.
     boot.initrd.postDeviceCommands = pkgs.lib.mkBefore ''
       mkdir /mnt