On Thu, 2022-09-08 at 14:22 -0400, J. Bruce Fields wrote: > On Thu, Sep 08, 2022 at 01:40:11PM -0400, Jeff Layton wrote: > > Yeah, ok. That does make some sense. So we would mix this into the > > i_version instead of the ctime when it was available. Preferably, we'd > > mix that in when we store the i_version rather than adding it afterward. > > > > Ted, how would we access this? Maybe we could just add a new (generic) > > super_block field for this that ext4 (and other filesystems) could > > populate at mount time? > > Couldn't the filesystem just return an ino_version that already includes > it? > Yes. That's simple if we want to just fold it in during getattr. If we want to fold that into the values stored on disk, then I'm a little less clear on how that will work. Maybe I need a concrete example of how that will work: Suppose we have an i_version value X with the previous crash counter already factored in that makes it to disk. We hand out a newer version X+1 to a client, but that value never makes it to disk. The machine crashes and comes back up, and we get a query for i_version and it comes back as X. Fine, it's an old version. Now there is a write. What do we do to ensure that the new value doesn't collide with X+1? -- Jeff Layton <jlayton@xxxxxxxxxx>
