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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 70A01C433ED for ; Tue, 21 Jul 2020 16:06:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F7A22077D for ; Tue, 21 Jul 2020 16:06:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="VUBjEX1C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730190AbgGUQGJ (ORCPT ); Tue, 21 Jul 2020 12:06:09 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:52130 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729094AbgGUQGJ (ORCPT ); Tue, 21 Jul 2020 12:06:09 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06LG3SUe077647; Tue, 21 Jul 2020 16:05:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=a7wjNPBX2VLwbGesoL6VTOkK6uEZ/3z/Ep3iy3hAJVE=; b=VUBjEX1Cb89azRfaE3KbHUUU97n75z1WMfoYZp/DbnK3PV+9qzitcv8lHl2/G6fqBI7s IxU1tTnUGxLuJN7Omi1t6JLOk9fbOEekBiO6fKxlWB7ZRo6TUSqHD7ZPHLVpiQfLdT72 F4/NHGZuypLDlTw6FFjrkkx6WY7tqxQNKoQWuZKl6fENTktbPLoMfZXNXS1dgiMhKWqh tqdiwcTiumSNDuHSzA6kEF8t/h8HA4tzB5g0pvJQdpUhz9UEcMsXCQvj/2rrsBWTNDqH uUOt+4BlArHi5n+pmYQn3Aez/GHwOtSw+k/fPcffQLpBR8B1VxOcelHC0Hska7zYtgdz DA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 32d6ksjdcu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 21 Jul 2020 16:05:46 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06LG4A4i054834; Tue, 21 Jul 2020 16:05:46 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 32e3j403mk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Jul 2020 16:05:46 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 06LG5iAF015966; Tue, 21 Jul 2020 16:05:44 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 21 Jul 2020 16:05:44 +0000 Date: Tue, 21 Jul 2020 09:05:42 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Matthew Wilcox , Goldwyn Rodrigues , Dave Chinner , Damien Le Moal , Naohiro Aota , Johannes Thumshirn , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, cluster-devel@redhat.com, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, Michael Kerrisk , linux-man@vger.kernel.org Subject: Re: RFC: iomap write invalidation Message-ID: <20200721160542.GD3151642@magnolia> References: <20200720215125.bfz7geaftocy4r5l@fiona> <20200721145313.GA9217@lst.de> <20200721150432.GH15516@casper.infradead.org> <20200721150615.GA10330@lst.de> <20200721151437.GI15516@casper.infradead.org> <20200721151616.GA11074@lst.de> <20200721152754.GD7597@magnolia> <20200721154132.GA11652@lst.de> <20200721155925.GB3151642@magnolia> <20200721160143.GA12046@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721160143.GA12046@lst.de> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9689 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=1 mlxlogscore=999 phishscore=0 mlxscore=0 adultscore=0 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007210113 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9689 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=1 bulkscore=0 mlxscore=0 mlxlogscore=999 impostorscore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 spamscore=0 adultscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007210113 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Jul 21, 2020 at 06:01:43PM +0200, Christoph Hellwig wrote: > On Tue, Jul 21, 2020 at 08:59:25AM -0700, Darrick J. Wong wrote: > > In the comment that precedes iomap_dio_rw() for the iomap version, > > maybe let's just do that.. > > > ``direct_IO`` > > called by the generic read/write routines to perform direct_IO - > > that is IO requests which bypass the page cache and transfer > > data directly between the storage and the application's address > > space. This function can return -ENOTBLK to signal that it is > > necessary to fallback to buffered IO. Note that > > blockdev_direct_IO and variants can also return -ENOTBLK. > > ->direct_IO is not used for iomap and various other implementations. > In fact it is a horrible hack that I've been trying to get rid of > for a while. Agreed, but for now there are still a number of fses who are still on the old directio code; let's try to keep the drainbamage/confusion potential to a minimum so it doesn't spread to our iomap shinyness. :) --D