File systems aren't databases, but journaling file systems use journals just like databases. It can theoretically define any granularity for something that might happen to a file to become an irreversible transaction. I suppose that file systems have to remain “general purpose enough” to be useful (otherwise they become part of the specific program or library), and that's why complex features which might become a pitfall for the regular users who expect “just regular files” rarely become the main focus.