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=-2.2 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 203AFC33CB1 for ; Tue, 14 Jan 2020 09:05:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 010172075B for ; Tue, 14 Jan 2020 09:05:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728780AbgANJFJ (ORCPT ); Tue, 14 Jan 2020 04:05:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:45004 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbgANJFJ (ORCPT ); Tue, 14 Jan 2020 04:05:09 -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 EA9FBAC54; Tue, 14 Jan 2020 09:05:07 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 8589F1E0D0E; Tue, 14 Jan 2020 10:05:07 +0100 (CET) Date: Tue, 14 Jan 2020 10:05:07 +0100 From: Jan Kara To: "Darrick J. Wong" Cc: Ritesh Harjani , linux-ext4@vger.kernel.org, tytso@mit.edu, jack@suse.cz Subject: Re: [RFC 1/2] iomap: direct-io: Move inode_dio_begin before filemap_write_and_wait_range Message-ID: <20200114090507.GA6466@quack2.suse.cz> References: <27607a16327fe9664f32d09abe565af0d1ae56c9.1578907891.git.riteshh@linux.ibm.com> <20200113215159.GA8235@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200113215159.GA8235@magnolia> 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 Mon 13-01-20 13:51:59, Darrick J. Wong wrote: > On Mon, Jan 13, 2020 at 04:34:21PM +0530, Ritesh Harjani wrote: > > Some filesystems (e.g. ext4) need to know in it's writeback path, that > > whether DIO is in progress or not. This info may be needed to avoid the > > stale data exposure race with DIO reads. > > Does XFS have this problem too? > > Admittedly dio read during mmap write is probably not well supported. ;) 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. Honza -- Jan Kara SUSE Labs, CR