Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754676AbbDNUEa (ORCPT ); Tue, 14 Apr 2015 16:04:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753202AbbDNUEV (ORCPT ); Tue, 14 Apr 2015 16:04:21 -0400 Date: Tue, 14 Apr 2015 13:04:18 -0700 From: Zach Brown To: Christoph Hellwig Cc: "J. Bruce Fields" , Anna Schumaker , Jeff Layton , Trond Myklebust , Linux Kernel Mailing List , Linux FS-devel Mailing List , linux-btrfs@vger.kernel.org, Linux NFS Mailing List , linux-scsi@vger.kernel.org Subject: Re: [PATCH RFC 1/3] vfs: add copy_file_range syscall and vfs helper Message-ID: <20150414200418.GA24660@lenny.home.zabbo.net> References: <20150411000208.GA20949@lenny.home.zabbo.net> <20150411090402.67d22d02@tlielax.poochiereds.net> <20150414165344.GA21421@infradead.org> <552D4B5D.3090904@Netapp.com> <20150414181911.GA2080@fieldses.org> <20150414182241.GB23129@lenny.home.zabbo.net> <20150414182906.GB2080@fieldses.org> <20150414185408.GC23129@lenny.home.zabbo.net> <20150414192325.GB20599@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150414192325.GB20599@infradead.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1007 Lines: 21 On Tue, Apr 14, 2015 at 12:23:25PM -0700, Christoph Hellwig wrote: > On Tue, Apr 14, 2015 at 11:54:08AM -0700, Zach Brown wrote: > > Is this relying on btrfs range cloning being atomic? It certainly > > doesn't look atomic. It can modify items across an arbitrarily large > > number of leaf blocks. It can make the changes across multiple > > transactions which could introduce partial modification on reboot after > > crashes. It can fail (the dynamic duo: enomem, eio) and leave the > > desintation partially modified. > > I didn't mean atomic in the failure atomic sense, but in the sense of > being atomic vs other writes, similar to how Posix specifies it for > writes vs other writes. Guess I need to express this intent better. Ah, right, OK. - z -- 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/