On Wed, 17 Aug 2022, Dave Chinner wrote: > > In XFS, we've defined the on-disk i_version field to mean > "increments with any persistent inode data or metadata change", > regardless of what the high level applications that use i_version > might actually require. > > That some network filesystem might only need a subset of the > metadata to be covered by i_version is largely irrelevant - if we > don't cover every persistent inode metadata change with i_version, > then applications that *need* stuff like atime change notification > can't be supported. So what you are saying is that the i_version provided by XFS does not match the changeid semantics required by NFSv4. Fair enough. I guess we shouldn't use the one to implement the other then. Maybe we should just go back to using ctime. ctime is *exactly* what NFSv4 wants, as long as its granularity is sufficient to catch every single change. Presumably XFS doesn't try to ensure this. How hard would it be to get any ctime update to add at least one nanosecond? This would be enabled by a mount option, or possibly be a direct request from nfsd. <rant>NFSv4 changeid is really one of the more horrible parts of the design</rant> NeilBrown
