On Mon, 2023-07-24 at 11:20 -0400, Chuck Lever wrote: > On Mon, Jul 24, 2023 at 10:53:39AM -0400, Jeff Layton wrote: > > In the event that we can't fetch post_op_attr attributes, we still need > > to set a value for the after_change. The operation has already happened, > > so we're not able to return an error at that point, but we do want to > > ensure that the client knows that its cache should be invalidated. > > > > If we weren't able to fetch post-op attrs, then just set the > > after_change to before_change + 1. The atomic flag should already be > > clear in this case. > > > > Suggested-by: Neil Brown <neilb@xxxxxxx> > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > --- > > fs/nfsd/nfs4proc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > I'm not sure this change makes any difference. The client would > possibly see the change value move forward then back. I'd think a > false "atomic" field and using the /same/ pre- and post-change would > be safer...? > > But I'm intrigued enough to apply this to nfsd-next provisionally, > at least for testing and further review. It will appear a little > later today. > > Thanks. I think there really are no great choices here. This is a rather unlikely error case that should only come into play when there are problems with the underlying filesystem, but only when fetching the post-op attrs. We don't have a way to just opt out of providing a post-op attribute and I think this is probably the least bad option of what to put in there. > > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c > > index 3f6710c9c5c9..f0f318e78630 100644 > > --- a/fs/nfsd/nfs4proc.c > > +++ b/fs/nfsd/nfs4proc.c > > @@ -411,7 +411,7 @@ set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp) > > if (WARN_ON_ONCE(!fhp->fh_pre_saved)) > > cinfo->before_change = 0; > > if (!fhp->fh_post_saved) > > - cinfo->after_change = 0; > > + cinfo->after_change = cinfo->before_change + 1; > > } > > > > static __be32 > > > > --- > > base-commit: 97a5d0146ef443df148805a4e9c3c44111f14ab1 > > change-id: 20230724-bz2223560-5ed6bc3a5db7 > > > > Best regards, > > -- > > Jeff Layton <jlayton@xxxxxxxxxx> > > > -- Jeff Layton <jlayton@xxxxxxxxxx>
