Return-Path: Received: from fieldses.org ([173.255.197.46]:35036 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752024AbdFQSYM (ORCPT ); Sat, 17 Jun 2017 14:24:12 -0400 Date: Sat, 17 Jun 2017 14:24:11 -0400 From: "J. Bruce Fields" To: Christoph Hellwig Cc: Olga Kornievskaia , Andreas Dilger , Olga Kornievskaia , "linux-fsdevel@vger.kernel.org" , linux-nfs Subject: Re: [PATCH 1/1] [RFC] 64bit copy_file_range system call Message-ID: <20170617182411.GA5399@fieldses.org> References: <20170614170653.58083-1-kolga@netapp.com> <20170615081502.GA10599@infradead.org> <20170616173630.GE12030@fieldses.org> <20170617100309.GA9469@infradead.org> <20170617150938.GA28885@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170617150938.GA28885@infradead.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Sat, Jun 17, 2017 at 08:09:38AM -0700, Christoph Hellwig wrote: > On Sat, Jun 17, 2017 at 08:42:54AM -0400, Olga Kornievskaia wrote: > > > > > On Jun 17, 2017, at 6:03 AM, Christoph Hellwig wrote: > > > > > > On Fri, Jun 16, 2017 at 01:36:30PM -0400, J. Bruce Fields wrote: > > >> It makes a difference in the clone case, doesn't it? (Though I'd think > > >> best there would be a special "copy to end of file" value.) > > > > > > Clones uses a 0 length as "whole" file. Both for the NFS operation > > > and the Linux ioctl. > > > > Does that actually work? There is check vfs_copy_file_range() > > Please re-read the above sentence. I'm talking about NFS clone and > IOC_CLONE_RANGE, not copy_file_range. copy_file_range had to follow > the NFS semantics that don't have the special 0 case. Nope, COPY has it: https://tools.ietf.org/html/rfc7862#section-15.2.3 A count of 0 (zero) requests that all bytes from ca_src_offset through EOF be copied to the destination. I think leaving it out of copy_file_range was just an oversight. --b.