From 4c13c933229d62de6e3928508b2f81a878b43e6d Mon Sep 17 00:00:00 2001
From: MidAutumnMoon <me@418.im>
Date: Wed, 26 Nov 2025 14:03:46 +0800
Subject: [PATCH] nixos/zram-as-tmp: fix boot failure caused by e2fsprogs not
 available

This module made the assumption that `e2fsprogs` will always be
available in `system.fsPackages`, whereas on my system with tmpfs as
root+btrfs setup, e2fsprogs is not added to `fsPackages`, causing zram-generator
failed to find mkfs.ext4.

Related log:

```
systemd-makefs[555]: mkfs binary for ext4 is not available.
```

(cherry picked from commit fb093b46b596527484d311f799d1568ad467862d)
---
 nixos/modules/system/boot/zram-as-tmp.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/nixos/modules/system/boot/zram-as-tmp.nix b/nixos/modules/system/boot/zram-as-tmp.nix
index 194e7c1659ff..b87bd373ed24 100644
--- a/nixos/modules/system/boot/zram-as-tmp.nix
+++ b/nixos/modules/system/boot/zram-as-tmp.nix
@@ -85,6 +85,10 @@ in
       }
     ];
 
+    boot.supportedFilesystems = {
+      ${cfg.zramSettings.fs-type} = true;
+    };
+
     services.zram-generator.enable = true;
     services.zram-generator.settings =
       let