nixos/profiles/base: enable bcachefs with kernel >= 6.7

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

@@ -33,6 +33,8 @@
 
 - `nixos-option` has been rewritten to a Nix expression called by a simple bash script. This lowers our maintenance threshold, makes eval errors less verbose, adds support for flake-based configurations, descending into `attrsOf` and `listOf` submodule options, and `--show-trace`.
 
+- `bcachefs` is now enabled in the installation media when kernel is at least 6.7.
+
 - The Mattermost module ({option}`services.mattermost`) and packages (`mattermost` and `mmctl`) have been substantially updated:
   - `pkgs.mattermostLatest` is now an option to track the latest (non-prerelease) Mattermost release. We test upgrade migrations from ESR releases (`pkgs.mattermost`) to `pkgs.mattermostLatest`.
   - The Mattermost frontend is now built from source and can be overridden.

nixos/modules/profiles/base.nix

@@ -45,8 +45,15 @@
   # Include support for various filesystems and tools to create / manipulate them.
   boot.supportedFilesystems =
     [ "btrfs" "cifs" "f2fs" "ntfs" "vfat" "xfs" ] ++
+    lib.optional (config.boot.kernelPackages.kernel.kernelAtLeast "6.7") "bcachefs" ++
     lib.optional (lib.meta.availableOn pkgs.stdenv.hostPlatform config.boot.zfs.package) "zfs";
 
+  # Might be required as a workaround for bcachefs bug
+  # https://github.com/NixOS/nixpkgs/issues/32279#issuecomment-1093682970
+  boot.postBootCommands = lib.optional (config.boot.supportedFilesystems.bcachefs) ''
+    ${lib.getExe' pkgs.keyutils "keyctl"} link @u @s
+  '';
+
   # Configure host id for ZFS to work
   networking.hostId = lib.mkDefault "8425e349";
 }