$ cd /tmp
$ truncate -s 500M img
$ mkdir -p mnt
$ mkfs.btrfs
$ run0 mount img mnt
$ run0 chmod 777 mnt
$ cd mnt
$ yes > y
yes: standard output: No space left on device
$ install y y2
install: cannot install 'y' to 'y2': No space left on device (os error 28)
$ gnu9.11-install y y2 # success
