nixos/profiles: enable bcachefs for new-kernel profile

nixos/doc/manual/release-notes/rl-2505.section.md

@@ -45,6 +45,8 @@
   - A new `pkgs.mattermost.buildPlugin` function has been added, which allows plugins to be built from source, including webapp frontends with a supported package-lock.json. See the Mattermost NixOS test and [manual](https://nixos.org/manual/nixpkgs/unstable/#sec-mattermost-plugins-build) for an example.
   - Note that the Mattermost module will create an account _without_ a well-known UID if the username differs from the default (`mattermost`). If you used Mattermost with a nonstandard username, you may want to review the module changes before upgrading.
 
+- `bcachefs` is now enabled in the installation media with a suitable kernel.
+
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->
 
 ## New Modules {#sec-release-25.05-new-modules}

nixos/modules/profiles/new-kernel.nix

@@ -1,8 +1,15 @@
 {
+  lib,
   pkgs,
   ...
 }:
 
 {
   boot.kernelPackages = pkgs.linuxPackages_latest;
+  boot.supportedFilesystems = [ "bcachefs" ];
+  # Might be required as a workaround for bcachefs bug
+  # https://github.com/NixOS/nixpkgs/issues/32279#issuecomment-1093682970
+  boot.postBootCommands = ''
+    ${lib.getExe pkgs.keyutils "keyctl"} link @u @s
+  '';
 }