ephermal systemd unit is now for host agnostic; moved io to disko disk management

hosts/modules/ephermal.nix

@@ -0,0 +1,64 @@
+{
+  hostType,
+  lib,
+  ...
+}:
+
+{
+  config = lib.mkMerge [
+    # Common configuration
+    {
+    }
+
+    # Server specific configuration
+    (lib.mkIf hostType.isServer {
+    })
+
+    # Workstation specific configuration
+    (lib.mkIf hostType.isWorkstation {
+      boot.initrd.systemd.services.recreate-root = {
+        description = "Rolling over and creating new filesystem root";
+        requires = [ "initrd-root-device.target" ];
+        after = [
+          "local-fs-pre.target"
+          "initrd-root-device.target"
+        ];
+        requiredBy = [ "initrd-root-fs.target" ];
+        before = [ "sysroot.mount" ];
+        unitConfig = {
+          AssertPathExists = "/etc/initrd-release";
+          DefaultDependencies = false;
+        };
+        serviceConfig = {
+          Type = "oneshot";
+          RemainAfterExit = true;
+        };
+        script = ''
+          mkdir /btrfs_tmp
+          mount /dev/mapper/cryptroot /btrfs_tmp
+
+          if [[ -e /btrfs_tmp/@root ]]; then
+            mkdir -p /btrfs_tmp/old_roots
+            timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/@root)" "+%Y-%m-%-d_%H:%M:%S")
+            mv /btrfs_tmp/@root "/btrfs_tmp/old_roots/$timestamp"
+          fi
+
+          delete_subvolume_recursively() {
+            IFS=$'\n'
+            for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
+               delete_subvolume_recursively "/btrfs_tmp/$i"
+            done
+            btrfs subvolume delete "$1"
+          }
+
+          for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
+            delete_subvolume_recursively "$i"
+          done
+
+          btrfs subvolume create /btrfs_tmp/@root
+          umount /btrfs_tmp
+        '';
+      };
+    })
+  ];
+}