From 23a13b562cb7f1dd8a13aba1863a16aee329019b Mon Sep 17 00:00:00 2001
From: Danylo Hlynskyi <abcz2.uprola@gmail.com>
Date: Thu, 17 Jan 2019 15:24:44 +0200
Subject: [PATCH] kernel config: add support for CONFIG_SQUASHFS_ZSTD (#52967)

Also, allow override `make-squashfs.nix` compression parameters.
---
 nixos/lib/make-squashfs.nix                     | 5 ++++-
 pkgs/os-specific/linux/kernel/common-config.nix | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/nixos/lib/make-squashfs.nix b/nixos/lib/make-squashfs.nix
index 7ab84e47f53..ee76c9c5bf2 100644
--- a/nixos/lib/make-squashfs.nix
+++ b/nixos/lib/make-squashfs.nix
@@ -3,6 +3,9 @@
 , # The root directory of the squashfs filesystem is filled with the
   # closures of the Nix store paths listed here.
   storeContents ? []
+, # Compression parameters.
+  # For zstd compression you can use "zstd -Xcompression-level 6".
+  comp ? "xz -Xdict-size 100%"
 }:
 
 stdenv.mkDerivation {
@@ -20,6 +23,6 @@ stdenv.mkDerivation {
 
       # Generate the squashfs image.
       mksquashfs nix-path-registration $(cat $closureInfo/store-paths) $out \
-        -keep-as-directory -all-root -b 1048576 -comp xz -Xdict-size 100%
+        -keep-as-directory -all-root -b 1048576 -comp ${comp}
     '';
 }
diff --git a/pkgs/os-specific/linux/kernel/common-config.nix b/pkgs/os-specific/linux/kernel/common-config.nix
index ab4b1cc2fc9..1466b51b261 100644
--- a/pkgs/os-specific/linux/kernel/common-config.nix
+++ b/pkgs/os-specific/linux/kernel/common-config.nix
@@ -320,6 +320,7 @@ let
       SQUASHFS_LZO                 = yes;
       SQUASHFS_XZ                  = yes;
       SQUASHFS_LZ4                 = yes;
+      SQUASHFS_ZSTD                = whenAtLeast "4.14" yes;
 
       # Native Language Support modules, needed by some filesystems
       NLS              = yes;