From: "Randy.Dunlap" Subject: Re: rfc: [patch] change attribute for ext3 Date: Wed, 13 Sep 2006 13:31:36 -0700 Message-ID: <20060913133136.449c731a.rdunlap@xenotime.net> References: <20060913164202.GA14838@openx1.frec.bull.fr> <1158171071.6072.10.camel@lade.trondhjem.org> <20060913183001.GA1702@moule.localdomain> <1158174362.6072.27.camel@lade.trondhjem.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Alexandre Ratchov , linux-ext4@vger.kernel.org, nfsv4@linux-nfs.org Return-path: Received: from xenotime.net ([66.160.160.81]:9699 "HELO xenotime.net") by vger.kernel.org with SMTP id S1751086AbWIMUaZ (ORCPT ); Wed, 13 Sep 2006 16:30:25 -0400 Received: from midway.site ([71.117.233.155]) by xenotime.net for ; Wed, 13 Sep 2006 13:30:25 -0700 To: Trond Myklebust In-Reply-To: <1158174362.6072.27.camel@lade.trondhjem.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, 13 Sep 2006 15:06:02 -0400 Trond Myklebust wrote: > On Wed, 2006-09-13 at 20:30 +0200, Alexandre Ratchov wrote: > > On Wed, Sep 13, 2006 at 02:11:11PM -0400, Trond Myklebust wrote: > > > On Wed, 2006-09-13 at 18:42 +0200, Alexandre Ratchov wrote: > > > > hello, > > > > > > > > here is a small patch that adds the "change attribute" for ext3 > > > > file-systems; > > > > > > > > the change attribute is a simple counter that is reset to zero on > > > > inode creation and that is incremented every time the inode data is > > > > modified (similarly to the "ctime" time-stamp). > > > > > > I would really have preferred a full-blown 64-bit counter as per > > > RFC3530, but I suppose we could always combine this change attribute > > > with the high word from ctime in order to make up the NFSv4 change > > > attribute. That should keep us safe until someone develops a ramdisk > > > with < 1 nsecond access time. > > > > > > > do you mean something like "(ctime.tv_sec << 32) | change_attribute"? this > > would allow 2^32 inode changes per second. > > Yes. As I said, that probably ought to suffice for now. > > > For ext3 it's hard to find unused bits in the on-disk inode structure, but > > ext4 inode may become larger in the future, allowing a 64bit counter. > > In anticipation of that event, could you please change the field in > 'struct stat' and 'struct stat64' to be an 'unsigned long long' instead > of the current 'unsigned long'? > > All the other fields are internal to the kernel, so a future change of > their size should not matter. and while you are making changes + resubmitting, Signed-off-by: needs to have name + email address. --- ~Randy