From be10e86c9587d3207c8d4a850a72ed88124d1aac Mon Sep 17 00:00:00 2001
From: Will Fancher <elvishjerricco@gmail.com>
Date: Sat, 19 Mar 2022 23:00:27 -0400
Subject: [PATCH] systemd-initrd: Partially fix qemu-vm

TODO: Auto formatting / partitioning / resizing
---
 nixos/modules/virtualisation/qemu-vm.nix | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index 514389358947..f8653a6f34a8 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -953,6 +953,28 @@ in
           };
       } // lib.mapAttrs' mkSharedDir cfg.sharedDirectories);
 
+    boot.initrd.systemd = lib.mkIf (config.boot.initrd.systemd.enable && cfg.writableStore) {
+      mounts = [{
+        where = "/sysroot/nix/store";
+        what = "overlay";
+        type = "overlay";
+        options = "lowerdir=/sysroot/nix/.ro-store,upperdir=/sysroot/nix/.rw-store/store,workdir=/sysroot/nix/.rw-store/work";
+        wantedBy = ["local-fs.target"];
+        before = ["local-fs.target"];
+        requires = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
+        after = ["sysroot-nix-.ro\\x2dstore.mount" "sysroot-nix-.rw\\x2dstore.mount" "rw-store.service"];
+        unitConfig.IgnoreOnIsolate = true;
+      }];
+      services.rw-store = {
+        after = ["sysroot-nix-.rw\\x2dstore.mount"];
+        unitConfig.DefaultDependencies = false;
+        serviceConfig = {
+          Type = "oneshot";
+          ExecStart = "/bin/mkdir -p 0755 /sysroot/nix/.rw-store/store /sysroot/nix/.rw-store/work /sysroot/nix/store";
+        };
+      };
+    };
+
     swapDevices = mkVMOverride [ ];
     boot.initrd.luks.devices = mkVMOverride {};