From d19c223ba6285da363e8bb8022e67a52c7bb9e0a Mon Sep 17 00:00:00 2001
From: Shea Levy <shea@shealevy.com>
Date: Sun, 16 Dec 2012 13:07:42 -0500
Subject: [PATCH] Simplify unionfs-chroot bind-mounting

---
 modules/installer/cd-dvd/iso-image.nix | 16 ++++++++--------
 modules/virtualisation/qemu-vm.nix     | 10 +++++-----
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/modules/installer/cd-dvd/iso-image.nix b/modules/installer/cd-dvd/iso-image.nix
index c9d443441e36..33000a3fbf1d 100644
--- a/modules/installer/cd-dvd/iso-image.nix
+++ b/modules/installer/cd-dvd/iso-image.nix
@@ -202,20 +202,20 @@ in
   # /nix/store (the squashfs image) to make this a live CD.
   boot.initrd.postMountCommands =
     ''
-      mkdir -p /unionfs-chroot$targetRoot
-      mount --rbind $targetRoot /unionfs-chroot$targetRoot
+      mkdir -p /unionfs-chroot/ro-root
+      mount --rbind $targetRoot /unionfs-chroot/ro-root
 
-      mkdir /unionfs-chroot/mnt-root-tmpfs
-      mount -t tmpfs -o "mode=755" none /unionfs-chroot/mnt-root-tmpfs
+      mkdir /unionfs-chroot/rw-root
+      mount -t tmpfs -o "mode=755" none /unionfs-chroot/rw-root
       mkdir /mnt-root-union
-      unionfs -o allow_other,cow,chroot=/unionfs-chroot /mnt-root-tmpfs=RW:$targetRoot=RO /mnt-root-union
+      unionfs -o allow_other,cow,chroot=/unionfs-chroot /rw-root=RW:/ro-root=RO /mnt-root-union
       oldTargetRoot=$targetRoot
       targetRoot=/mnt-root-union
 
-      mkdir /unionfs-chroot/mnt-store-tmpfs
-      mount -t tmpfs -o "mode=755" none /unionfs-chroot/mnt-store-tmpfs
+      mkdir /unionfs-chroot/rw-store
+      mount -t tmpfs -o "mode=755" none /unionfs-chroot/rw-store
       mkdir -p $oldTargetRoot/nix/store
-      unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /mnt-store-tmpfs=RW:$oldTargetRoot/nix/store=RO /mnt-root-union/nix/store
+      unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /rw-store=RW:/ro-root/nix/store=RO /mnt-root-union/nix/store
     '';
 
   # Closures to be copied to the Nix store on the CD, namely the init
diff --git a/modules/virtualisation/qemu-vm.nix b/modules/virtualisation/qemu-vm.nix
index 8d50da8296c0..0367379b2444 100644
--- a/modules/virtualisation/qemu-vm.nix
+++ b/modules/virtualisation/qemu-vm.nix
@@ -286,12 +286,12 @@ in
       mkdir -p $targetRoot/boot
       mount -o remount,ro $targetRoot/nix/store
       ${optionalString cfg.writableStore ''
-        mkdir -p /unionfs-chroot$targetRoot
-        mount --rbind $targetRoot /unionfs-chroot$targetRoot
+        mkdir -p /unionfs-chroot/ro-store
+        mount --rbind $targetRoot/nix/store /unionfs-chroot/ro-store
 
-        mkdir /unionfs-chroot/mnt-store-tmpfs
-        mount -t tmpfs -o "mode=755" none /unionfs-chroot/mnt-store-tmpfs
-        unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /mnt-store-tmpfs=RW:$targetRoot/nix/store=RO $targetRoot/nix/store
+        mkdir /unionfs-chroot/rw-store
+        mount -t tmpfs -o "mode=755" none /unionfs-chroot/rw-store
+        unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot /rw-store=RW:/ro-store=RO $targetRoot/nix/store
       ''}
     '';