Fix restoring snapshot on boot

machines/elendel/default.nix

@@ -42,6 +42,7 @@
       zfs = {
         enable = true;
         rootDataset = "zroot/local/root";
+        rootPool = "zroot";
       };
     };
   };

machines/kholinar/default.nix

@@ -31,6 +31,7 @@
           }
         ];
         rootDataset = "rpool/local/root";
+        rootPool = "rpool";
       };
     };
     development = {

machines/lasting-integrity/default.nix

@@ -68,6 +68,7 @@
           }
         ];
         rootDataset = "zroot/local/root";
+        rootPool = "zroot";
       };
     };
     games = {

machines/marabethia/default.nix

@@ -30,6 +30,7 @@
       zfs = {
         enable = true;
         rootDataset = "zroot/local/root";
+        rootPool = "zroot";
       };
     };
   };

machines/urithiru/default.nix

@@ -55,6 +55,7 @@
           }
         ];
         rootDataset = "zroot/local/root";
+        rootPool = "zroot";
       };
     };
     services = {

modules/nixos/base/zfs/default.nix

@@ -1,4 +1,4 @@
-{ config, lib, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   config = lib.mkIf config.chvp.base.zfs.enable {
@@ -8,9 +8,21 @@
     boot = {
       supportedFilesystems = [ "zfs" ];
       zfs.requestEncryptionCredentials = config.chvp.base.zfs.encrypted;
-      initrd.postDeviceCommands = lib.mkAfter ''
+      initrd.systemd = {
-        zfs rollback -r ${config.chvp.base.zfs.rootDataset}@blank
+        enable = true;
-      '';
+        services.rollback = {
+          description = "Rollback root filesystem to a pristine state on boot";
+          wantedBy = [ "initrd.target" ];
+          after = [ "zfs-import-${config.chvp.base.zfs.rootPool}.service" ];
+          before = [ "sysroot.mount" ];
+          path = with pkgs; [ zfs ];
+          unitConfig.DefaultDependencies = "no";
+          serviceConfig.Type = "oneshot";
+          script = ''
+            zfs rollback -r ${config.chvp.base.zfs.rootDataset}@blank && echo "  >> >> rollback complete << <<"
+          '';
+        };
+      };
     };
 
     services = {

modules/shared/base/zfs/default.nix

@@ -45,5 +45,8 @@
     rootDataset = lib.mkOption {
       example = "rpool/local/root";
     };
+    rootPool = lib.mkOption {
+      example = "rpool";
+    };
   };
 }