% mount | grep btrfs
/dev/vdb on / type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=266,subvol=/lxd/storage-pools/default/containers/penguin/rootfs)
/dev/vdb on /dev/wl0 type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=5,subvol=/lxd/devices/penguin/unix.wl0.dev-wl0)
