From 95fc4eb09de428094f60694aef4b54e21a025402 Mon Sep 17 00:00:00 2001
From: Atemu <atemu.main@gmail.com>
Date: Tue, 8 Jun 2021 06:23:27 +0200
Subject: [PATCH] nixos/btrfs: handle new checksum types in initrd

Can't mount a root formatted with those otherwise

(cherry picked from commit e85f2f43bda6e0fe245005b710091f854a7f0200)
---
 nixos/modules/tasks/filesystems/btrfs.nix | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/tasks/filesystems/btrfs.nix b/nixos/modules/tasks/filesystems/btrfs.nix
index c0ff28039b1..ae1dab5b8d8 100644
--- a/nixos/modules/tasks/filesystems/btrfs.nix
+++ b/nixos/modules/tasks/filesystems/btrfs.nix
@@ -55,7 +55,16 @@ in
     (mkIf enableBtrfs {
       system.fsPackages = [ pkgs.btrfs-progs ];
 
-      boot.initrd.kernelModules = mkIf inInitrd [ "btrfs" "crc32c" ];
+      boot.initrd.kernelModules = mkIf inInitrd [ "btrfs" ];
+      boot.initrd.availableKernelModules = mkIf inInitrd (
+        [ "crc32c" ]
+        ++ optionals (config.boot.kernelPackages.kernel.kernelAtLeast "5.5") [
+          # Needed for mounting filesystems with new checksums
+          "xxhash_generic"
+          "blake2b_generic"
+          "sha256_generic" # Should be baked into our kernel, just to be sure
+        ]
+      );
 
       boot.initrd.extraUtilsCommands = mkIf inInitrd
       ''