Swap file creation on btrfs

Support
9 
ID 1834 gen 107681 top level 5 uuid 550fac1e-bc55-f449-ac83-7dbfdfa76040 path @swap
sudo mount /var/lib/systemd-swap/
mount: /var/lib/systemd-swap/: can't find UUID=550fac1e-bc55-f449-ac83-7dbfdfa76040.