From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754020Ab3BUUud (ORCPT ); Thu, 21 Feb 2013 15:50:33 -0500 Received: from mx12.netapp.com ([216.240.18.77]:13170 "EHLO mx12.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753513Ab3BUUua convert rfc822-to-8bit (ORCPT ); Thu, 21 Feb 2013 15:50:30 -0500 X-IronPort-AV: E=Sophos;i="4.84,711,1355126400"; d="scan'208";a="24985303" From: "Myklebust, Trond" To: Paolo Bonzini CC: Ric Wheeler , Linux FS Devel , "linux-kernel@vger.kernel.org" , "Chris L. Mason" , Christoph Hellwig , Alexander Viro , "Martin K. Petersen" , Hannes Reinecke , "Joel Becker" Subject: Re: New copyfile system call - discuss before LSF? Thread-Topic: New copyfile system call - discuss before LSF? Thread-Index: AQHOECfzherspfmEjEqBTzfvhb3EUJiE2wAAgAASTQCAAFTBgIAADekA Date: Thu, 21 Feb 2013 20:50:27 +0000 Message-ID: <4FA345DA4F4AE44899BD2B03EEEC2FA9235DAA99@SACEXCMBX04-PRD.hq.netapp.com> References: <512606DF.5050706@redhat.com> <4FA345DA4F4AE44899BD2B03EEEC2FA9235D998C@SACEXCMBX04-PRD.hq.netapp.com> <512635D2.4090207@redhat.com> <51267CEB.8070805@redhat.com> In-Reply-To: <51267CEB.8070805@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.104.60.115] Content-Type: text/plain; charset=US-ASCII Content-ID: Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-02-21 at 21:00 +0100, Paolo Bonzini wrote: > Il 21/02/2013 15:57, Ric Wheeler ha scritto: > >>> > >> sendfile64() pretty much already has the right arguments for a > >> "copyfile", however it would be nice to add a 'flags' parameter: the > >> NFSv4.2 version would use that to specify whether or not to copy file > >> metadata. > > > > That would seem to be enough to me and has the advantage that it is an > > relatively obvious extension to something that is at least not totally > > unknown to developers. > > > > Do we need more than that for non-NFS paths I wonder? What does reflink > > need or the SCSI mechanism? > > For virt we would like to be able to specify arbitrary block ranges. > Copying an entire file helps some copy operations like storage > migration. However, it is not enough to convert the guest's offloaded > copies to host-side offloaded copies. So how would a system call based on sendfile64() plus my flag parameter prevent an underlying implementation from meeting your criterion? -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com