From d4b3a096c020145183dfa756c15d142b5491dc69 Mon Sep 17 00:00:00 2001
From: Paul Meyer <katexochen0@gmail.com>
Date: Fri, 20 Dec 2024 09:24:31 +0100
Subject: [PATCH] nixos/image: use erofs-utils' --hard-dereference flag

to make image builds reproducible between systems with nix store optimization enables/disabled.

Signed-off-by: Paul Meyer <katexochen0@gmail.com>
---
 packages/nixos/image.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/nixos/image.nix b/packages/nixos/image.nix
index caf834473..f21f1bafe 100644
--- a/packages/nixos/image.nix
+++ b/packages/nixos/image.nix
@@ -28,6 +28,12 @@ in
       name = "image-podvm-gpu";
       inherit (config.system.image) version;
 
+      mkfsOptions.erofs = [
+        # Dereference hardlinks to avoid different number of inodes between images
+        # built on systems with nix store optimization enabled and disabled.
+        "--hard-dereference"
+      ];
+
       # This defines the actual partition layout.
       partitions = {
         # EFI System Partition, holds the UKI.