> Broken? Yes, it is breaking the promise of what it is supposed to do. If fsync() was defined as "will ensure your data is on disk, unless that's kinda slow,

> Broken? Yes, it is breaking the promise of what it is supposed to do. If fsync() was defined as "will ensure your data is on disk, unless that's kinda slow, then who knows", then the behaviour would not be broken, just potentially useless for many applications. But if you promise to ensure something is stored on disk, and then don't, that's the definition of being broken.