Return-Path: Received: from mout.kundenserver.de ([212.227.126.130]:64481 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753132AbcEINJZ (ORCPT ); Mon, 9 May 2016 09:09:25 -0400 From: Arnd Bergmann To: Steve French Cc: David Howells , linux-fsdevel , linux-afs@vger.kernel.org, "linux-nfs@vger.kernel.org" , samba-technical , LKML , "linux-ext4@vger.kernel.org" , Deepa Dinamani Subject: Re: [RFC][PATCH 0/6] Enhanced file stat system call Date: Mon, 09 May 2016 15:09:04 +0200 Message-ID: <4211584.odaTcq8sN6@wuerfel> In-Reply-To: References: <20160429125736.23636.47874.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thursday 05 May 2016 21:00:18 Steve French wrote: > On Thu, May 5, 2016 at 5:54 PM, Steve French wrote: > > On Wed, May 4, 2016 at 8:46 AM, Arnd Bergmann wrote: > >> On Friday 29 April 2016 13:57:36 David Howells wrote: > >>> struct statx *buffer); > >>> > >>> This is an enhanced file stat function that provides a number of useful > >>> features, in summary: > >>> > >>> (1) More information: creation time, data version number, inode > >>> generation > >>> number and flags. A subset of these is available through a number of > >>> filesystems (such as CIFS, NFS, AFS, Ext4 and BTRFS). > >>> > >> > >> I have a question about birthtime/creationtime: As we are gaining a way > >> to read this, should we also provide a way to update it using a new > >> variant > >> of the utimensat syscall in order to have 'cp -a' create an identical > >> copy, > >> or is the idea that this is defined as the time that is particular copy > >> of the inode was created? > >> > >> I've discussed this with Deepa in the past, as she is driving the > >> convertion of the inode timestamps to timespec64 now, and we will > >> need a new version of utimensat for her work as well. I can see good > >> reasons either way (allowing updates of btime or disallowing them). > > > It would help interop with Windows (and presumably Mac) if birth time can be > updated Ok, thanks. That is certainly a good reason in favor. If nothing else comes up, I guess we can prepare a patch for a new utimensat variant to do this and wait for more comments on that. Arnd