initial commit

hosts/server-n0-darling-erasure.sh

@@ -0,0 +1,23 @@
+mkdir -p /mnt
+
+echo "--- erasing system state begin ---"
+# We first mount the btrfs root to /mnt
+# so we can manipulate btrfs subvolumes.
+mount -o subvol=/ /dev/disk/by-uuid/5dfd3b74-2162-4167-825b-21259ca48820 /mnt
+
+# back up the old root (important!!)
+BOOTID=$(date +"@boot-%Y_%m_%d-%H_%M_%S-%s")
+echo "backing up old root: /mnt/@root/ -> /mnt/@old-roots/$BOOTID..."
+echo "note that the timestamp is of *this* boot, not of the boot that created the old root!"
+mv /mnt/@root /mnt/@old-roots/$BOOTID
+btrfs property set -f -ts /mnt/@old-roots/$BOOTID ro true
+
+echo "restoring blank /@root subvolume..."
+btrfs subvolume snapshot /mnt/@root-blank /mnt/@root
+
+# Once we're done rolling back to a blank snapshot,
+# we can unmount /mnt and continue on the boot process.
+echo "--- erasing system state end ---"
+
+umount /mnt
+