nixos/filesystems: init erofs

Enable using an erofs filesystem as one of the filesystems needed to boot the system. This is useful for example in image based deployments where the Nix store is mounted read only. [erofs](https://docs.kernel.org/filesystems/erofs.html) offers multiple benefits over older filesystems like squashfs. Skip fsck.erofs because it is still experimental.
2023-05-11 14:35:00 +02:00
parent b15daed965
commit fa09e0a3c7
4 changed files with 120 additions and 44 deletions
--- a/nixos/tests/non-default-filesystems.nix
+++ b/nixos/tests/non-default-filesystems.nix
@@ -1,55 +1,106 @@
-import ./make-test-python.nix ({ lib, pkgs, ... }:
+{ system ? builtins.currentSystem
+, config ? { }
+, pkgs ? import ../.. { inherit system config; }
+}:
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+with pkgs.lib;
 {
-  name = "non-default-filesystems";
-
-  nodes.machine =
-    { config, pkgs, lib, ... }:
-    let
-      disk = config.virtualisation.rootDevice;
-    in
+  btrfs = makeTest
    {
-      virtualisation.rootDevice = "/dev/vda";
-      virtualisation.useDefaultFilesystems = false;
+      name = "non-default-filesystems-btrfs";

-      boot.initrd.availableKernelModules = [ "btrfs" ];
-      boot.supportedFilesystems = [ "btrfs" ];
+      nodes.machine =
+        { config, pkgs, lib, ... }:
+        let
+          disk = config.virtualisation.rootDevice;
+        in
+        {
+          virtualisation.rootDevice = "/dev/vda";
+          virtualisation.useDefaultFilesystems = false;

-      boot.initrd.postDeviceCommands = ''
-        FSTYPE=$(blkid -o value -s TYPE ${disk} || true)
-        if test -z "$FSTYPE"; then
-          modprobe btrfs
-          ${pkgs.btrfs-progs}/bin/mkfs.btrfs ${disk}
+          boot.initrd.availableKernelModules = [ "btrfs" ];
+          boot.supportedFilesystems = [ "btrfs" ];

-          mkdir /nixos
-          mount -t btrfs ${disk} /nixos
+          boot.initrd.postDeviceCommands = ''
+            FSTYPE=$(blkid -o value -s TYPE ${disk} || true)
+            if test -z "$FSTYPE"; then
+              modprobe btrfs
+              ${pkgs.btrfs-progs}/bin/mkfs.btrfs ${disk}

-          ${pkgs.btrfs-progs}/bin/btrfs subvolume create /nixos/root
-          ${pkgs.btrfs-progs}/bin/btrfs subvolume create /nixos/home
+              mkdir /nixos
+              mount -t btrfs ${disk} /nixos

-          umount /nixos
-        fi
+              ${pkgs.btrfs-progs}/bin/btrfs subvolume create /nixos/root
+              ${pkgs.btrfs-progs}/bin/btrfs subvolume create /nixos/home
+
+              umount /nixos
+            fi
+          '';
+
+          virtualisation.fileSystems = {
+            "/" = {
+              device = disk;
+              fsType = "btrfs";
+              options = [ "subvol=/root" ];
+            };
+
+            "/home" = {
+              device = disk;
+              fsType = "btrfs";
+              options = [ "subvol=/home" ];
+            };
+          };
+        };
+
+      testScript = ''
+        machine.wait_for_unit("multi-user.target")
+
+        with subtest("BTRFS filesystems are mounted correctly"):
+          machine.succeed("grep -E '/dev/vda / btrfs rw,relatime,space_cache=v2,subvolid=[0-9]+,subvol=/root 0 0' /proc/mounts")
+          machine.succeed("grep -E '/dev/vda /home btrfs rw,relatime,space_cache=v2,subvolid=[0-9]+,subvol=/home 0 0' /proc/mounts")
      '';
-
-      virtualisation.fileSystems = {
-        "/" = {
-          device = disk;
-          fsType = "btrfs";
-          options = [ "subvol=/root" ];
-        };
-
-        "/home" = {
-          device = disk;
-          fsType = "btrfs";
-          options = [ "subvol=/home" ];
-        };
-      };
    };

-  testScript = ''
-    machine.wait_for_unit("multi-user.target")
+  erofs =
+    let
+      fsImage = "/tmp/non-default-filesystem.img";
+    in
+    makeTest {
+      name = "non-default-filesystems-erofs";

-    with subtest("BTRFS filesystems are mounted correctly"):
-      machine.succeed("grep -E '/dev/vda / btrfs rw,relatime,space_cache=v2,subvolid=[0-9]+,subvol=/root 0 0' /proc/mounts")
-      machine.succeed("grep -E '/dev/vda /home btrfs rw,relatime,space_cache=v2,subvolid=[0-9]+,subvol=/home 0 0' /proc/mounts")
-  '';
-})
+      nodes.machine = _: {
+        virtualisation.qemu.drives = [{
+          name = "non-default-filesystem";
+          file = fsImage;
+        }];
+
+        virtualisation.fileSystems."/non-default" = {
+          device = "/dev/vdb";
+          fsType = "erofs";
+          neededForBoot = true;
+        };
+      };
+
+      testScript = ''
+        import subprocess
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as tmp_dir:
+          with open(f"{tmp_dir}/filesystem", "w") as f:
+              f.write("erofs")
+
+          subprocess.run([
+            "${pkgs.erofs-utils}/bin/mkfs.erofs",
+            "${fsImage}",
+            tmp_dir,
+          ])
+
+        machine.start()
+        machine.wait_for_unit("default.target")
+
+        file_contents = machine.succeed("cat /non-default/filesystem")
+        assert "erofs" in file_contents
+      '';
+    };
+}