Return-Path: Received: from mx144.netapp.com ([216.240.21.25]:5174 "EHLO mx144.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757516AbbI1O2Y (ORCPT ); Mon, 28 Sep 2015 10:28:24 -0400 Subject: Re: [PATCH v3 8/9] vfs: copy_file_range() can do a pagecache copy with splice To: Andy Lutomirski References: <1443214096-12769-1-git-send-email-Anna.Schumaker@Netapp.com> <1443214096-12769-9-git-send-email-Anna.Schumaker@Netapp.com> CC: , Linux btrfs Developers List , Linux FS Devel , Linux API , Zach Brown , Al Viro , Chris Mason , "Darrick J. Wong" , Michael Kerrisk-manpages , , Christoph Hellwig From: Anna Schumaker Message-ID: <56094E82.2070800@Netapp.com> Date: Mon, 28 Sep 2015 10:28:18 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: On 09/25/2015 08:14 PM, Andy Lutomirski wrote: > On Fri, Sep 25, 2015 at 1:48 PM, Anna Schumaker > wrote: >> The NFS server will need some kind offallback for filesystems that don't >> have any kind of copy acceleration, and it should be generally useful to >> have an in-kernel copy to avoid lots of switches between kernel and user >> space. >> >> I make this configurable by adding two new flags. Users who only want a >> reflink can pass COPY_FR_REFLINK, and users who want a full data copy can >> pass COPY_FR_COPY. The default (flags=0) means to first attempt a >> reflink, but use the pagecache if that fails. >> > > Can you clarify how the subject line fits in? I'm a bit lost. I'll try! I use the splice interface to copy file data from the pagecache, and this implements an in-kernel copy that can be controlled using the two flags I added. I plan on using this in the NFS server when I add server-side copy support. Let me know if that doesn't answer your question! Anna > > --Andy >