From: "J. Bruce Fields" Subject: Re: [RFC PATCH v1 00/30] fs: inode->i_version rework and optimization Date: Tue, 21 Mar 2017 13:51:29 -0400 Message-ID: <20170321175129.GC17872@fieldses.org> References: <1482339827-7882-1-git-send-email-jlayton@redhat.com> <20161222084549.GA8833@infradead.org> <1482417724.3924.39.camel@redhat.com> <20170320214327.GA5098@fieldses.org> <20170321134500.GA1318@infradead.org> <20170321163011.GA16666@fieldses.org> <1490117004.2542.1.camel@redhat.com> <20170321173704.GA17872@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org To: Jeff Layton Return-path: Content-Disposition: inline In-Reply-To: <20170321173704.GA17872@fieldses.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Mar 21, 2017 at 01:37:04PM -0400, J. Bruce Fields wrote: > On Tue, Mar 21, 2017 at 01:23:24PM -0400, Jeff Layton wrote: > > On Tue, 2017-03-21 at 12:30 -0400, J. Bruce Fields wrote: > > > - NFS doesn't actually require that it increases, but I think it > > > should. I assume 64 bits means we don't need a discussion of > > > wraparound. > > > > I thought NFS spec required that you be able to recognize old change > > attributes so that they can be discarded. I could be wrong here though. > > I'd have to go back and look through the spec to be sure. > > https://tools.ietf.org/html/rfc7862#section-10 So, I'm suggesting we implement this one: NFS4_CHANGE_TYPE_IS_MONOTONIC_INCR: The change attribute value MUST monotonically increase for every atomic change to the file attributes, data, or directory contents. It may be a slight lie--after your patches we wouldn't actually increase "for every atomic change". I think that's OK. --b.