update for SteamOS 3.6

README.md

@@ -11,10 +11,10 @@ Once installed, you can use the `steamos-rw` command to enable, disable, or rese
 ## Details
 The overlay data is stored in a disk image at `/home/.steamos/offload/usr.img` alongside the rest of the SteamOS offload folders.
 That disk image is mounted to `/var/lib/overlays/usr` alongside the `etc` overlay folder (`var-lib-overlay-usr.mount`).
-Finally, overlayfs is used the same way as SteamOS does with the `etc` overlay to enable writing to the `usr` folder (`usr.mount`), which allows you to use pacman.
+Overlayfs is used the same way as SteamOS does with the `etc` overlay to enable writing to the `usr` folder (`usr.mount`), which allows you to use pacman.
 Additionally, all the pre-installed packages are added to the pacman `IgnorePkg` list (`/etc/pacman.conf`) to prevent you from borking your system with a `pacman -Syu`.
 Next, the default mirrorlist (`/etc/pacman.d/mirrorlist`) has to have `SigLevel = Optional TrustAll` added to work at all, thanks to valve somehow breaking package/repo signing.
-After initializing the pacman keyring, `pacman-contrib` is installed to get the `paccache` service, which will help prevent pacman cache from filling up the small `/var` partition.
+Since SteamOS 3.6, the pacman cache is stored on the home partition, removing the need for the paccache service, and the atomic-update config allows us to exclude steamos-rw files from being removed with updates.
 To get systemd services like tailscale working, a system and user service (`overlay-units.service`) is added to issue start commands to enabled services, since they show up in the system too late for systemd to automatically start them.
 Finally, `steamos-rw.target` and the `steamos-rw` command allow you to easily control the overlay.
 You can also use `steamos-rw reset` to re-format the overlay disk image if you'd like to reset your installed software.

atomic-update.conf

@@ -0,0 +1,8 @@
+/etc/systemd/system/usr.mount
+/etc/systemd/system/var-lib-overlays-usr.mount
+/etc/systemd/system/steamos-rw.target
+/etc/systemd/system/overlay-units.service
+/etc/systemd/user/overlay-units.service
+/etc/atomic-update.conf.d/steamos-rw.conf
+/etc/pacman.conf
+/etc/pacman.d

install.sh

@@ -10,6 +10,7 @@ set -xeuo pipefail
 
 cp *.target *.service *.mount /etc/systemd/system/
 cp *.service /etc/systemd/user/
+cp atomic-update.conf /etc/atomic-update.conf.d/steamos-rw.conf 
 systemctl daemon-reload
 
 truncate /home/.steamos/offload/usr.img -s $(blockdev --getsize64 $(findmnt -n -o SOURCE --target /home))
@@ -19,6 +20,7 @@ systemctl start var-lib-overlays-usr.mount
 mkdir -p /var/lib/overlays/usr/work /var/lib/overlays/usr/upper
 systemctl enable steamos-rw.target --now
 ln -s $PWD/steamos-rw.sh /bin/steamos-rw
+chmod +x /bin/steamos-rw
 
 cat <<EOF >> /etc/pacman.conf
 # block updates for steamos pre-installed packages
@@ -31,8 +33,6 @@ cat <<EOF >> /etc/pacman.d/mirrorlist
 SigLevel = Optional TrustAll
 EOF
 pacman-key --init
-pacman -Syu pacman-contrib --noconfirm
-systemctl enable paccache.timer
 
 set +x
 read -rp "Install complete, you may close this window or press enter to exit"

overlay-units.service

@@ -3,6 +3,7 @@ Description = start overlayed systemd units
 Requires=usr.mount
 After=usr.mount
 After=default.target
+PartOf=steamos-rw.target
 
 [Service]
 Type=oneshot

uninstall.sh

@@ -13,4 +13,8 @@ cd /etc/systemd/system
 rm usr.mount steamos-rw.target overlay-units.service var-lib-overlays-usr.mount
 cd /etc/system/user
 rm overlay-units.service
+cd /var/lib/overlays
+rm -rf usr
+cd /etc/atomic-update.conf.d/
+rm steamos-rw.conf
 reboot

var-lib-overlays-usr.mount

@@ -1,5 +1,6 @@
 [Unit]
 Description = SteamOS-RW Offload - /usr
+PartOf=steamos-rw.target
 
 [Mount]
 What=/home/.steamos/offload/usr.img