1 files changed, 29 insertions, 1 deletions
diff --git a/machines/aszlig/dnyarri.nix b/machines/aszlig/dnyarri.nix
index e060aac6..7e42f607 100644
--- a/machines/aszlig/dnyarri.nix
+++ b/machines/aszlig/dnyarri.nix
@@ -1,4 +1,4 @@
-{ pkgs, lib, ... }:
+{ config, pkgs, utils, lib, ... }:
 
 let
   mkDevice = category: num: uuid: {
@@ -19,6 +19,20 @@ let
     ];
   };
 
+  bcacheMode = "writearound";
+
+  bcacheStart = ''
+    for i in /sys/block/bcache[0-9]*/bcache/cache_mode; do
+      echo ${lib.escapeShellArg bcacheMode} > "$i"
+    done
+  '';
+
+  bcacheStop = ''
+    for i in /sys/block/bcache[0-9]*/bcache/cache_mode; do
+      echo none > "$i"
+    done
+  '';
+
 in {
   vuizvui.user.aszlig.profiles.workstation.enable = true;
 
@@ -78,10 +92,24 @@ in {
   powerManagement.powerUpCommands = ''
     ${pkgs.hdparm}/sbin/hdparm -B 255 /dev/disk/by-id/ata-ST31500541AS_5XW0AMNH
     ${pkgs.hdparm}/sbin/hdparm -B 255 /dev/disk/by-id/ata-ST31500541AS_6XW0M217
+    ${bcacheStart}
   '';
 
+  powerManagement.powerDownCommands = bcacheStop;
+
   services.btrfs.autoScrub.enable = true;
 
+  # Inject preStart/postStart for activating/deactivating bcache to the scrub
+  # services, so we don't get large amounts of nonsense on the caching device.
+  systemd.services = let
+    scrubServiceUnits = let
+      mkName = fs: "btrfs-scrub-${utils.escapeSystemdPath fs}.service";
+    in map mkName config.services.btrfs.autoScrub.fileSystems;
+  in lib.genAttrs scrubServiceUnits (lib.const {
+    preStart = bcacheStop;
+    postStart = bcacheStart;
+  });
+
   swapDevices = map ({ name, ... }: {
     device = "/dev/mapper/${name}";
   }) cryptDevices.swap;