linux_testing_bcachefs: upstream tarballs rather patchsets

This reverts commit cb1b1cf9c6.

bcachefs lacks behind kernel mainline, so we need to use upstream
commits rather than patchsets.

pkgs/os-specific/linux/kernel/linux-testing-bcachefs.nix

@@ -1,33 +1,23 @@
-{ lib
-, fetchpatch
-, kernel
-, date ? "2021-07-08"
-, commit ? "3693b2ca83ff9eda49660b31299d2bebe3a1075f"
-, diffHash ? "1sfq3vwc2kxa761s292f2cqrm0vvqvkdx6drpyn5yaxwnapwidcw"
-, kernelPatches # must always be defined in bcachefs' all-packages.nix entry because it's also a top-level attribute supplied by callPackage
-, argsOverride ? {}
-, ...
-} @ args:
+{ lib, buildPackages, fetchFromGitHub, fetchpatch, perl, buildLinux, ... } @ args:
 
-(kernel.override ( args // {
+buildLinux (args // {
+  version = "5.13.0-2021.10.01";
+  modDirVersion = "5.13.0";
+
+  src = fetchFromGitHub {
+    owner = "koverstreet";
+    repo = "bcachefs";
+    rev = "4114ced1db465b8f4e7f4d6a78aa11416a9ab5d9";
+    sha256 = "sha256-viFC3HHIcjUTDPvloSKKsz9PuSLyvxfYnrtkVUB79mQ=";
+  };
+
+  extraConfig = "BCACHEFS_FS m";
 
-  argsOverride = {
-    version = "${kernel.version}-bcachefs-unstable-${date}";
   extraMeta = {
     branch = "master";
+    hydraPlatforms = []; # Should the testing kernels ever be built on Hydra?
     maintainers = with lib.maintainers; [ davidak chiiruno ];
     platforms = [ "x86_64-linux" ];
   };
-  } // argsOverride;
 
-  kernelPatches = [ {
-      name = "bcachefs-${commit}";
-      patch = fetchpatch {
-        name = "bcachefs-${commit}.diff";
-        url = "https://evilpiepirate.org/git/bcachefs.git/rawdiff/?id=${commit}&id2=v${lib.versions.majorMinor kernel.version}";
-        sha256 = diffHash;
-      };
-      extraConfig = "BCACHEFS_FS m";
-    } ] ++ kernelPatches;
-
-})).overrideAttrs ({ meta ? {}, ... }: { meta = meta // { broken = true; }; })
+} // (args.argsOverride or {}))