framework-2024-11-25-00-02-03

configs/common.nix

@@ -5,14 +5,73 @@
   inputs,
   ...
 }: {
+  nixpkgs = {
+    config = {
+      allowUnfree = true;
+    };
+  };
+
   boot = {
+    loader = {
+      efi.canTouchEfiVariables = true;
+      grub = {
+        enable = true;
+        device = "nodev";
+        efiSupport = true;
+        configurationLimit = 5;
+        enableCryptodisk = true;
+        useOSProber = true;
+      };
+    };
+
     tmp = {
       useTmpfs = lib.mkDefault true;
       cleanOnBoot = true;
     };
     consoleLogLevel = 0;
     kernel.sysctl = {"vm.max_map_count" = 262144;};
-    supportedFilesystems = ["ntfs"];
+    supportedFilesystems = ["ntfs" "btrfs"];
+
+    initrd = {
+      postDeviceCommands = pkgs.lib.mkBefore ''
+        mkdir -p /mnt
+
+        # We first mount the btrfs root to /mnt
+        # so we can manipulate btrfs subvolumes.
+        mount -o subvol=/ /dev/mapper/lvm-root /mnt
+
+        # While we're tempted to just delete /root and create
+        # a new snapshot from /root-blank, /root is already
+        # populated at this point with a number of subvolumes,
+        # which makes `btrfs subvolume delete` fail.
+        # So, we remove them first.
+        #
+        # /root contains subvolumes:
+        # - /root/var/lib/portables
+        # - /root/var/lib/machines
+        #
+        # I suspect these are related to systemd-nspawn, but
+        # since I don't use it I'm not 100% sure.
+        # Anyhow, deleting these subvolumes hasn't resulted
+        # in any issues so far, except for fairly
+        # benign-looking errors from systemd-tmpfiles.
+        btrfs subvolume list -o /mnt/root |
+        cut -f9 -d' ' |
+        while read subvolume; do
+          echo "deleting /$subvolume subvolume..."
+          btrfs subvolume delete "/mnt/$subvolume"
+        done &&
+        echo "deleting /root subvolume..." &&
+        btrfs subvolume delete /mnt/root
+
+        echo "restoring blank /root subvolume..."
+        btrfs subvolume snapshot /mnt/root-blank /mnt/root
+
+        # Once we're done rolling back to a blank snapshot,
+        # we can unmount /mnt and continue on the boot process.
+        umount /mnt
+      '';
+    };
   };
 
   # Work around for https://github.com/NixOS/nixpkgs/issues/124215
@@ -88,6 +147,23 @@
       man-pages
       man-pages-posix
     ];
+
+    persistence."/persist" = {
+      directories = [
+        "/var/lib/nixos"
+        "/var/lib/tailscale"
+        "/var/lib/tuptime"
+        "/var/lib/vnstat"
+      ];
+      files = [
+        "/etc/machine-id"
+        "/etc/NIXOS"
+        "/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"
+      ];
+    };
   };
 
   i18n = {