On Wed, Sep 07, 2022 at 09:37:33PM +1000, NeilBrown wrote: > On Wed, 07 Sep 2022, Jeff Layton wrote: > > +The change to \fIstatx.stx_ino_version\fP is not atomic with respect to the > > +other changes in the inode. On a write, for instance, the i_version it usually > > +incremented before the data is copied into the pagecache. Therefore it is > > +possible to see a new i_version value while a read still shows the old data. > > Doesn't that make the value useless? Surely the change number must > change no sooner than the change itself is visible, otherwise stale data > could be cached indefinitely. For the purposes of NFS close-to-open, I guess all we need is for the change attribute increment to happen sometime between the open and the close. But, yes, it'd seem a lot more useful if it was guaranteed to happen after. (Or before and after both--extraneous increments aren't a big problem here.) --b. > > If currently implementations behave this way, surely they are broken. > > NeilBrown