From 328f87c12f4f1961a525d05ce435bfce4ab07e7c Mon Sep 17 00:00:00 2001
From: Scott Worley <scottworley@scottworley.com>
Date: Thu, 4 Jun 2026 14:13:51 -0700
Subject: [PATCH] Use bcarnes' squashfs label patches instead of the dubious
 kludge

---
 .../libblkid-squashfs-nix-store-kludge.patch  | 19 ------------------
 modules/qemu-vm-isolation.nix                 | 20 +++++++++++++++----
 2 files changed, 16 insertions(+), 23 deletions(-)
 delete mode 100644 modules/libblkid-squashfs-nix-store-kludge.patch

diff --git a/modules/libblkid-squashfs-nix-store-kludge.patch b/modules/libblkid-squashfs-nix-store-kludge.patch
deleted file mode 100644
index de971f7..0000000
--- a/modules/libblkid-squashfs-nix-store-kludge.patch
+++ /dev/null
@@ -1,19 +0,0 @@
-# This dubious kludge results from
-# https://github.com/NixOS/nixpkgs/pull/236656 requiring filesystems to have labels and
-# https://github.com/plougher/squashfs-tools/issues/59 squashfs not supporting labels.
-diff --git a/libblkid/src/superblocks/squashfs.c b/libblkid/src/superblocks/squashfs.c
-index 4db842493..ed7465882 100644
---- a/libblkid/src/superblocks/squashfs.c
-+++ b/libblkid/src/superblocks/squashfs.c
-@@ -45,6 +45,11 @@ static int probe_squashfs(blkid_probe pr, const struct blkid_idmag *mag)
- 
- 	blkid_probe_sprintf_version(pr, "%u.%u", vermaj, vermin);
- 
-+	{
-+		char label_kludge[] = "nix-store";
-+		blkid_probe_set_label(pr, label_kludge, sizeof(label_kludge));
-+	}
-+
- 	return 0;
- }
- 
diff --git a/modules/qemu-vm-isolation.nix b/modules/qemu-vm-isolation.nix
index 69bacde..5467f29 100644
--- a/modules/qemu-vm-isolation.nix
+++ b/modules/qemu-vm-isolation.nix
@@ -49,6 +49,17 @@ let
       }/nix-store.img";
     squashfs =
       "${hostPkgs.callPackage (modulesPath + "/../lib/make-squashfs.nix") {
+        squashfsTools = hostPkgs.squashfsTools.overrideAttrs (old: {
+          # We patch in support for squashfs labels because
+          # https://github.com/NixOS/nixpkgs/pull/236656 requires filesystems to have labels and
+          # https://github.com/plougher/squashfs-tools/issues/59 squashfs doesn't support labels
+          patches = (old.patches or []) ++ [ ./squashfs-tools-label.patch ];
+          buildInputs = (old.buildInputs or []) ++ [ hostPkgs.makeWrapper ];
+          postInstall = (old.postInstall or "") + ''
+            wrapProgram "$out/bin/mksquashfs" \
+              --append-flags "-label nix-store"
+          '';
+        });
         storeContents = config.virtualisation.additionalPaths;
       }}";
   };
@@ -61,8 +72,7 @@ in {
 
         erofs is more compact than ext4, but less mature.
 
-        squashfs support currently requires a dubious kludge that results in these
-        VMs not being able to mount any other squashfs volumes besides the nix store.
+        squashfs is best, but requires patches to set the filesystem label.
       '';
       type = lib.types.enum [ "ext4" "erofs" "squashfs" ];
       default = "ext4";
@@ -76,8 +86,10 @@ in {
       nixpkgs.overlays = optional (cfg.nixStoreFilesystemType == "squashfs")
         (final: prev: {
           util-linux = prev.util-linux.overrideAttrs (old: {
-            patches = (old.patches or [ ])
-              ++ [ ./libblkid-squashfs-nix-store-kludge.patch ];
+            # We patch in support for squashfs labels because
+            # https://github.com/NixOS/nixpkgs/pull/236656 requires filesystems to have labels and
+            # https://github.com/plougher/squashfs-tools/issues/59 squashfs doesn't support labels
+            patches = (old.patches or [ ]) ++ [ ./util-linux-squashfs-label.patch ];
           });
         });
 
-- 
2.51.2