Barriers are also used in btrfs.

and from what i can tell clone operations are also handled atomically

though i kinda wonder what exactly is meant by atomic writes.

Thanks for clearing that up.

I might have to dig into it a bit more.

Yeah, it depends on the use case. For home directories and large risk items like financial stuff, testing that barrier writes are happening is a good thing. You don't want a storm to knock out a DC to learn that the hw/sw fs stack was lying to you at some level.