From e866840a120976ad63882fa53fbddfd714cff93d Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Mon, 28 Sep 2015 21:50:22 +0200
Subject: [PATCH] Wait for udev after resizing partitions

Otherwise the EC2 boot may panic.
---
 nixos/modules/virtualisation/amazon-grow-partition.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/virtualisation/amazon-grow-partition.nix b/nixos/modules/virtualisation/amazon-grow-partition.nix
index 31899fae6c02..44a9fa93e7ec 100644
--- a/nixos/modules/virtualisation/amazon-grow-partition.nix
+++ b/nixos/modules/virtualisation/amazon-grow-partition.nix
@@ -39,7 +39,10 @@ in
     '';
 
     boot.initrd.postDeviceCommands = ''
-      [ -e /dev/xvda ] && [ -e /dev/xvda1 ] && TMPDIR=/run sh $(type -P growpart) /dev/xvda 1
+      if [ -e /dev/xvda ] && [ -e /dev/xvda1 ]; then
+        TMPDIR=/run sh $(type -P growpart) /dev/xvda 1
+        udevadm settle
+      fi
     '';
 
   };