On Tue, Aug 30, 2022 at 01:02:50PM -0400, Jeff Layton wrote: > The fact that NFS kept this more loosely-defined is what allowed us to > elide some of the i_version bumps and regain a fair bit of performance > for local filesystems [1]. If the change attribute had been more > strictly defined like you mention, then that particular optimization > would not have been possible. > > This sort of thing is why I'm a fan of not defining this any more > strictly than we require. Later on, maybe we'll come up with a way for > filesystems to advertise that they can offer stronger guarantees. Yeah, the afs change-attribute-as-counter thing seems ambitious--I wouldn't even know how to define what exactly you're counting. My one question is whether it'd be worth just defining the thing as *increasing*. That's a lower bar. (Though admittedly we don't quite manage it now--see again 1631087ba872 "Revert "nfsd4: support change_attr_type attribute"".) --b.
