From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:59403 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964943AbeEITId (ORCPT ); Wed, 9 May 2018 15:08:33 -0400 Subject: Re: [PATCH 2/4] copy_file_range: Perform splice if in/out SB are not same To: Florian Weimer , linux-fsdevel@vger.kernel.org Cc: hch@lst.de, smfrench@gmail.com, linux-unionfs@vger.kernel.org, david@fromorbit.com, Goldwyn Rodrigues References: <20180508212405.15297-1-rgoldwyn@suse.de> <20180508212405.15297-3-rgoldwyn@suse.de> From: Goldwyn Rodrigues Message-ID: <4afb2ef0-7cf9-a2c4-4ad8-d91f9ea3d3df@suse.de> Date: Wed, 9 May 2018 14:08:27 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 05/08/2018 04:57 PM, Florian Weimer wrote: > On 05/08/2018 11:24 PM, Goldwyn Rodrigues wrote: >> While performing copy_file_range(), if superblocks of file_in and >> file_out don't match, instead of returning -EXDEV, perform >> splice for a faster copy. > > We have a userspace emulation in glibc which used to be quite faithful, > including the EXDEV error (which is not strictly necessary to produce). > > Should we change glibc to perform a userspace copy if the system call > returns EXDEV due to an older kernel? > I don't seen any purpose. The user would anyways have to perform a copy if it receives -EXDEV. -- Goldwyn