On Mon, 2022-09-12 at 09:51 -0400, J. Bruce Fields wrote: > On Mon, Sep 12, 2022 at 08:55:04AM -0400, Jeff Layton wrote: > > Because of the "seen" flag, we have a 63 bit counter to play with. Could > > we use a similar scheme to the one we use to handle when "jiffies" > > wraps? Assume that we'd never compare two values that were more than > > 2^62 apart? We could add i_version_before/i_version_after macros to make > > it simple to handle this. > > As far as I recall the protocol just assumes it can never wrap. I guess > you could add a new change_attr_type that works the way you describe. > But without some new protocol clients aren't going to know what to do > with a change attribute that wraps. > Right, I think that's the case now, and with contemporary hardware that shouldn't ever happen, but in 10 years when we're looking at femtosecond latencies, could this be different? I don't know. > I think this just needs to be designed so that wrapping is impossible in > any realistic scenario. I feel like that's doable? > > If we feel we have to catch that case, the only 100% correct behavior > would probably be to make the filesystem readonly. What would be the recourse at that point? Rebuild the fs from scratch, I guess? -- Jeff Layton <jlayton@xxxxxxxxxx>
