From e6d17c8ca6060a3feebefa8a78716a19fad702d5 Mon Sep 17 00:00:00 2001
From: Haonan Chen <chn@chn.moe>
Date: Sun, 14 Dec 2025 11:51:50 +0800
Subject: [PATCH] modules.system.kernel: add 6.18 btrfs patch

---
 flake/src.nix             | 23 ++++++++++++++++++++++-
 modules/system/kernel.nix | 19 ++++++-------------
 2 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/flake/src.nix b/flake/src.nix
index 8d6a4746..55dddc22 100644
--- a/flake/src.nix
+++ b/flake/src.nix
@@ -1,4 +1,4 @@
-{ inputs }: let inherit (inputs.self.packages.x86_64-linux) pkgs; in
+{ inputs }: let inherit (inputs.self.packages.x86_64-linux) pkgs; inherit (inputs.nixpkgs) lib; in
 {
   nvhpc =
   {
@@ -208,4 +208,25 @@
       finalImageTag = "v8.0.12";
     };
   };
+  btrfs =
+  {
+    "6.12" =
+    {
+      patch = pkgs.fetchurl
+      {
+        url = "https://github.com/kakra/linux/pull/36.patch";
+        sha256 = "0wimihsvrxib6g23jcqdbvqlkqk6nbqjswfx9bzmpm1vlvzxj8m0";
+      };
+      structuredExtraConfig.BTRFS_EXPERIMENTAL = lib.kernel.yes;
+    };
+    "6.18" =
+    {
+      patch = pkgs.fetchurl
+      {
+        url = "https://github.com/kakra/linux/pull/40.patch";
+        sha256 = "00k57gx5xmwsdr83qc24dwkiin1qcyl929262m9kix699g7fclga";
+      };
+      structuredExtraConfig = { BTRFS_ALLOCATOR_HINTS = lib.kernel.yes; BTRFS_READ_POLICIES = lib.kernel.yes; };
+    };
+  };
 }
diff --git a/modules/system/kernel.nix b/modules/system/kernel.nix
index a0cd6f6a..dcc0b1dd 100644
--- a/modules/system/kernel.nix
+++ b/modules/system/kernel.nix
@@ -62,19 +62,12 @@ inputs:
         cachyos-rc = inputs.pkgs.linuxPackages_cachyos-rc;
       }.${kernel.variant};
       kernelPatches =
-        let patches =
-        {
-          btrfs =
-          [{
-            name = "btrfs";
-            patch = inputs.pkgs.fetchurl
-            {
-              url = "https://github.com/kakra/linux/pull/36.patch";
-              sha256 = "0wimihsvrxib6g23jcqdbvqlkqk6nbqjswfx9bzmpm1vlvzxj8m0";
-            };
-            structuredExtraConfig.BTRFS_EXPERIMENTAL = inputs.lib.kernel.yes;
-          }];
-        };
+        let
+          version = inputs.lib.versions.majorMinor inputs.config.boot.kernelPackages.kernel.version;
+          patches =
+          {
+            btrfs = [(inputs.topInputs.self.src.btrfs.${version} // { name = "btrfs"; })];
+          };
         in builtins.concatLists (builtins.map (name: patches.${name}) kernel.patches);
     };
   };