> you need to be absolutely, positively, 100% sure that `fsync()` has done The Right Thing would be: "Good luck with that!" But it's safe to assume the right t

> you need to be absolutely, positively, 100% sure that `fsync()` has done The Right Thing would be: "Good luck with that!" But it's safe to assume the right thing is not done if we haven't even called `fsync` to start with and just hope and pray that the dirty page flushing mechanism does it for us.