Comment by cmurf

Very rudimentary, but a way for an application developer to specify categories of perform/safety ratio operations. An app developer might have a simple app that only cares about performance, only cares about safety, there'd be a default in between both. Another app developer might have mixed needs depending on the type of data the app is generating. But in this way, if they write the app with a category of A (let's say that means highest safety at expense of performance) and their benchmarking determines this is crap, and they have to go to category B for writes, that's a simpler change that going back through their code and refactoring a pile of fsyncs or FUA writes.

I mean, I thought this was a major reason for VFS abstraction between the application and kernel anyway. It's also an example of the distinction between open source and free (libre). If as an application developer you have to know such esoterics to sanely optimize, you in fact aren't really free to do what you want. You have to go down a particular rabbit hole and optimize for that fs, at the expense of others. That's not fair choice to have to make.