Not commenting on whether OPs idea is sound or not, however tunefs implies the now less and less used ext4 (many distros are switching to XFS or btrfs :-/). On

Not commenting on whether OPs idea is sound or not, however tunefs implies the now less and less used ext4 (many distros are switching to XFS or btrfs :-/). On another note, that limit applies to non-privileged processes only. Some crap running as root will just fill up the disk too.