From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEED9C33CB1 for ; Wed, 15 Jan 2020 09:19:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA3842081E for ; Wed, 15 Jan 2020 09:19:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729281AbgAOJTd (ORCPT ); Wed, 15 Jan 2020 04:19:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:42446 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729270AbgAOJTd (ORCPT ); Wed, 15 Jan 2020 04:19:33 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 5EE8FAEFF; Wed, 15 Jan 2020 09:19:31 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id EA9E31E0CBC; Wed, 15 Jan 2020 10:19:25 +0100 (CET) Date: Wed, 15 Jan 2020 10:19:25 +0100 From: Jan Kara To: Christoph Hellwig Cc: Jan Kara , "Darrick J. Wong" , Ritesh Harjani , linux-ext4@vger.kernel.org, tytso@mit.edu Subject: Re: [RFC 1/2] iomap: direct-io: Move inode_dio_begin before filemap_write_and_wait_range Message-ID: <20200115091925.GC31450@quack2.suse.cz> References: <27607a16327fe9664f32d09abe565af0d1ae56c9.1578907891.git.riteshh@linux.ibm.com> <20200113215159.GA8235@magnolia> <20200114090507.GA6466@quack2.suse.cz> <20200114163818.GB7127@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200114163818.GB7127@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue 14-01-20 08:38:18, Christoph Hellwig wrote: > On Tue, Jan 14, 2020 at 10:05:07AM +0100, Jan Kara wrote: > > > > Well, XFS always performs buffered writeback using unwritten extents so at > > least the immediate problem of stale data exposure ext4 has does not happen > > there AFAICT. > > Currently XFS never uses unwritten extents when converting delalloc > extents. I see, it is a long time since I last looked at that part of XFS code. So then I think XFS might be prone to the same kind of race and data exposure as I outlined in [1]... Honza [1] https://lore.kernel.org/linux-ext4/20200114094741.GC6466@quack2.suse.cz -- Jan Kara SUSE Labs, CR