From d3468aa5e135dfa17592b1ad7463e1ceebb74b33 Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Mon, 3 Feb 2025 10:37:58 +0100
Subject: [PATCH] yodaTux swapfile

---
 README.md                                | 17 +++++++++++++----
 hosts/yodaTux/hardware-configuration.nix |  9 ++++++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 628b0d5..f48f44e 100644
--- a/README.md
+++ b/README.md
@@ -306,10 +306,19 @@ Filtering:
 Summary:
 
 * Create subvolume `@swap` directly below top-level subvolume.
-* Mount at `/swap`
-* Create swapfile: `sudo btrfs filesystem mkswapfile --size 8g --uuid clear /swap/swapfile`
-* Regenerate hardware-configuration: `sudo nixos-generate-config --dir hosts/$(hostname)`
-* Add `swapDevices = [ { device = "/swap/swapfile"; } ];` to hardware configuration and run `nixos-rebuild switch` (see above).
+  * `sudo mkdir -p /mnt/ssd`
+  * `sudo mount /dev/disk/by-uuid/01f67928-9b35-48b2-aaa6-c58ff6c440a8 /mnt/ssd`
+  * `sudo btrfs subvolume create /mnt/ssd/@swap`
+  * `sudo umount /mnt/ssd`
+* Mount subvolume at `/swap`.
+  * `sudo mkdir /swap`
+  * `sudo mount -o subvol=@swap /dev/disk/by-uuid/01f67928-9b35-48b2-aaa6-c58ff6c440a8 /swap`
+* Create swapfile `/swap/swapfile`.
+  * `sudo btrfs filesystem mkswapfile --size 8g --uuid clear /swap/swapfile`
+* Regenerate hardware-configuration. This will add `fileSystems."/swap"` to it.
+  * `sudo nixos-generate-config --dir hosts/$(hostname)`
+* Add `swapDevices = [ { device = "/swap/swapfile"; } ];` to hardware-configuration.
+* Apply your new NixOS config. This will activate the swapfile.
 
 ## BTRFS CoW
 
diff --git a/hosts/yodaTux/hardware-configuration.nix b/hosts/yodaTux/hardware-configuration.nix
index 6bd36a1..c3e6f47 100644
--- a/hosts/yodaTux/hardware-configuration.nix
+++ b/hosts/yodaTux/hardware-configuration.nix
@@ -24,9 +24,16 @@
   fileSystems."/boot" =
     { device = "/dev/disk/by-uuid/4840-0BFE";
       fsType = "vfat";
+      options = [ "fmask=0022" "dmask=0022" ];
     };
 
-  swapDevices = [ ];
+  fileSystems."/swap" =
+    { device = "/dev/disk/by-uuid/01f67928-9b35-48b2-aaa6-c58ff6c440a8";
+      fsType = "btrfs";
+      options = [ "subvol=@swap" ];
+    };
+
+  swapDevices = [ { device = "/swap/swapfile"; } ];
 
   # Enables DHCP on each ethernet and wireless interface. In case of scripted networking
   # (the default) this is the recommended approach. When using systemd-networkd it's