From 94ce6ec866a51ff8e520a1acc592f4de04b5759c Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 30 Jul 2014 13:10:03 +0200
Subject: [PATCH] Print a sensible error message if no device is specified for
 a filesystem

---
 nixos/modules/tasks/filesystems.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/tasks/filesystems.nix b/nixos/modules/tasks/filesystems.nix
index 4b189a801b2..d00f479754f 100644
--- a/nixos/modules/tasks/filesystems.nix
+++ b/nixos/modules/tasks/filesystems.nix
@@ -146,7 +146,9 @@ in
 
         # Filesystems.
         ${flip concatMapStrings fileSystems (fs:
-            (if fs.device != null then fs.device else "/dev/disk/by-label/${fs.label}")
+            (if fs.device != null then fs.device
+             else if fs.label != null then "/dev/disk/by-label/${fs.label}"
+             else throw "No device specified for mount point ‘${fs.mountPoint}’.")
             + " " + fs.mountPoint
             + " " + fs.fsType
             + " " + fs.options