Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933370Ab0G3Sk1 (ORCPT ); Fri, 30 Jul 2010 14:40:27 -0400 Received: from fieldses.org ([174.143.236.118]:40977 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933309Ab0G3SkP (ORCPT ); Fri, 30 Jul 2010 14:40:15 -0400 Date: Fri, 30 Jul 2010 14:38:19 -0400 To: Neil Brown Cc: David Howells , Linus Torvalds , Jan Engelhardt , Jeremy Allison , Volker.Lendecke@sernet.de, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH 02/18] xstat: Add a pair of system calls to make extended file stats available [ver #6] Message-ID: <20100730183819.GE21729@fieldses.org> References: <20100722162712.GB10352@jeremy-laptop> <13591.1280338082@redhat.com> <20100729090401.4b0a21f8@notabene> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100729090401.4b0a21f8@notabene> User-Agent: Mutt/1.5.20 (2009-06-14) From: "J. Bruce Fields" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1333 Lines: 30 On Thu, Jul 29, 2010 at 09:04:01AM +1000, Neil Brown wrote: > On Wed, 28 Jul 2010 18:28:02 +0100 > David Howells wrote: > > > Neil Brown wrote: > > > > > ctime and mtime have real cache-coherence semantics which require them being > > > updated by the kernel (whether the cache is on an NFS client, in a backup > > > archive, or in a .o translation of a .c file). > > > > So does creation time, at least for CIFS caching. Creation time has potential > > for spotting when the object at a pathname has changed for something else, > > given the lack of inode number and inode generation from windows servers. > > Creation time gives us one more datum to use. > > This justifies for me why a CIFS client would want to extract the > creation-time from the CIFS protocol, but not why you want to expose it via a > generic interface. > The kernel/filesystem doesn't need to maintain creation-time to meet this > need, only the CIFS server needs to maintain it For what it's worth, the NFSv4 server would also export creation time if we had it. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/