When installing ubuntu 18.04 (tested with the minimal install cd), and selecting a root filesystem on btrfs without swap partition, the creates a swapfile, but the swapfile can't be used on btrfs (see https://btrfs.wiki.kernel.org/index.php/FAQ#Does_btrfs_support_swap_files.3F).
The installer should no create this file and add it to /etc/fsab
When installing ubuntu 18.04 (tested with the minimal install cd), and selecting a root filesystem on btrfs without swap partition, the creates a swapfile, but the swapfile can't be used on btrfs (see https:/ /btrfs. wiki.kernel. org/index. php/FAQ# Does_btrfs_ support_ swap_files. 3F).
The installer should no create this file and add it to /etc/fsab