[Nix-dev] luks encrypted home stopped mounting after channel update

[Ellis Whitehead]

A few days ago, I ran `nixos-rebuild --switch` using the up-to-date
unstable channel, and everything worked fine.  Last night I updated
the channel again and rebuilt, but when I started my computer this
morning, it doesn't prompt for the encryption password anymore, and
home doesn't mount.  Any ideas?

I can get into my system by telling GRUB to boot the previous
configuration instead, so the partition itself is fine.  Nothing
changed in my configure.nix.  Here are the relevant lines:

---
    # Use the GRUB 2 boot loader.
    boot.loader.grub.enable = true;
    boot.loader.grub.version = 2;
    # Define on which hard drive you want to install Grub.
    boot.loader.grub.device = "/dev/sda";

    # Encrypted home
    boot.initrd.luks.devices = [ { device = "/dev/sda6"; name = "home"; } ];

    fileSystems."/home".device = "/dev/mapper/home";
---

And this is my hardware-configuration-lorax.nix:

---
# Do not modify this file!  It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations.  Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, pkgs, ... }:

{
  imports =
    [ <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
    ];

  boot.initrd.availableKernelModules = [ "ehci_pci" "ahci" "xhci_hcd"
"usbhid" ];
  boot.kernelModules = [ "kvm-intel" ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "/dev/sda5";
      fsType = "ext4";
    };

  swapDevices =[ ];

  nix.maxJobs = 4;
}
---

The error message in `journalctl -xb` is:
May 20 04:50:55 lorax systemd[1]: Job dev-mapper-home.device/start timed out.
May 20 04:50:55 lorax systemd[1]: Timed out waiting for device
dev-mapper-home.device.
May 20 04:50:55 lorax systemd[1]: Dependency failed for /home.
May 20 04:50:55 lorax systemd[1]: Dependency failed for Local File Systems.
May 20 04:50:55 lorax systemd[1]: Triggering OnFailure= dependencies
of local-fs.target.
May 20 04:50:55 lorax systemd[1]: Dependency failed for File System
Check on /dev/mapper/home.

The AES encryption modules is loaded, though.

Any ideas about how to get the system to ask for my encryption
password again?  Much appreciated,
Ellis