From: "J. Bruce Fields" Subject: Re: [PATCH-v2 0/5] add support for a lazytime mount option Date: Mon, 24 Nov 2014 17:11:45 -0500 Message-ID: <20141124221145.GB24003@fieldses.org> References: <1416675267-2191-1-git-send-email-tytso@mit.edu> <20141124090755.GA28534@infradead.org> <20141124115727.GA19918@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , linux-fsdevel@vger.kernel.org, Ext4 Developers List , xfs@oss.sgi.com, linux-btrfs@vger.kernel.org To: Theodore Ts'o Return-path: Content-Disposition: inline In-Reply-To: <20141124115727.GA19918@thunk.org> Sender: linux-btrfs-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, Nov 24, 2014 at 06:57:27AM -0500, Theodore Ts'o wrote: > If we want to be paranoid, we handle i_version updates non-lazily; I > can see arguments in favor of that. > > Ext4 only enables MS_I_VERSION if the user asks for it explicitly, so > it wouldn't cause me any problems. However, xfs and btrfs enables it > by default, so that means xfs and btrfs wouldn't see the benefits of > lazytime (if you're going to have to push I_VERSION to disk, you might > as well update the [acm]time while you're at it). I've always thought > that we *should* do is to only enable it if nfsv4 is serving the file > system, and not otherwise, though, which would also give us > consistency across all the file systems. I guess you need to worry about the case where you shutdown nfsd, modify a file, then restart nfsd--you don't want a client to miss the modification in that case. --b.