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=-5.5 required=3.0 tests=BAYES_00, 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 8CE9BC433E0 for ; Tue, 21 Jul 2020 16:01:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7126820720 for ; Tue, 21 Jul 2020 16:01:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730045AbgGUQBs (ORCPT ); Tue, 21 Jul 2020 12:01:48 -0400 Received: from verein.lst.de ([213.95.11.211]:52832 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727058AbgGUQBr (ORCPT ); Tue, 21 Jul 2020 12:01:47 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id E5A9068AFE; Tue, 21 Jul 2020 18:01:43 +0200 (CEST) Date: Tue, 21 Jul 2020 18:01:43 +0200 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , 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: <20200721160143.GA12046@lst.de> References: <20200713074633.875946-1-hch@lst.de> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721155925.GB3151642@magnolia> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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.