From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:9439 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725748AbeLBJty (ORCPT ); Sun, 2 Dec 2018 04:49:54 -0500 Date: Sun, 2 Dec 2018 09:36:17 +1100 From: Dave Chinner To: Matthew Wilcox Cc: Olga Kornievskaia , bfields@redhat.com, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 01/10] VFS generic copy_file_range() support Message-ID: <20181201223617.GR19305@dastard> References: <20181130200348.59524-1-olga.kornievskaia@gmail.com> <20181130200348.59524-2-olga.kornievskaia@gmail.com> <20181201211806.GO10377@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181201211806.GO10377@bombadil.infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Sat, Dec 01, 2018 at 01:18:06PM -0800, Matthew Wilcox wrote: > On Fri, Nov 30, 2018 at 03:03:39PM -0500, Olga Kornievskaia wrote: > > Relax the condition that input files must be from the same > > file systems. > > > + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, > > + count > MAX_RW_COUNT ? MAX_RW_COUNT : count, 0); > > Wasn't there a concern about splicing between filesystems with different > block sizes mentioned the last time this came up? I can't find a citation > for that now. the filesystems should be able to handle that themselves - they are just passes an iter that has a range of data regions in pages that they copy the required data into/out of. The data transfer mechanism itself is completely independent of filesystem block sizes.... There's lots of other problems with do_splice_direct, but I don't think this is one of them. I coul dbe wrong - this code has pretty much zero documentation on how it is supposed to work and what it is supposed to do - so don't take my word for it... Cheers, Dave. -- Dave Chinner david@fromorbit.com