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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 41EF5C43466 for ; Sat, 19 Sep 2020 06:51:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EFBE20796 for ; Sat, 19 Sep 2020 06:51:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726201AbgISGvc (ORCPT ); Sat, 19 Sep 2020 02:51:32 -0400 Received: from verein.lst.de ([213.95.11.211]:35048 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726112AbgISGvc (ORCPT ); Sat, 19 Sep 2020 02:51:32 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 2740768BFE; Sat, 19 Sep 2020 08:51:27 +0200 (CEST) Date: Sat, 19 Sep 2020 08:51:26 +0200 From: Christoph Hellwig To: Jan Kara Cc: Christoph Hellwig , Jens Axboe , Song Liu , Hans de Goede , Richard Weinberger , Minchan Kim , linux-mtd@lists.infradead.org, dm-devel@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com, linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org Subject: Re: [PATCH 10/12] bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag Message-ID: <20200919065126.GA8048@lst.de> References: <20200910144833.742260-1-hch@lst.de> <20200910144833.742260-11-hch@lst.de> <20200917092524.GC7347@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200917092524.GC7347@quack2.suse.cz> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On Thu, Sep 17, 2020 at 11:25:24AM +0200, Jan Kara wrote: > On Thu 10-09-20 16:48:30, Christoph Hellwig wrote: > > The BDI_CAP_STABLE_WRITES is one of the few bits of information in the > > backing_dev_info shared between the block drivers and the writeback code. > > To help untangling the dependency replace it with a queue flag and a > > superblock flag derived from it. This also helps with the case of e.g. > > a file system requiring stable writes due to its own checksumming, but > > not forcing it on other users of the block device like the swap code. > > > > One downside is that we can't support the stable_pages_required bdi > > attribute in sysfs anymore. It is replaced with a queue attribute, that > > can also be made writable for easier testing. > ^^^^^^^^^^^^^^^^ > is also made > > For a while I was confused thinking that the new attribute is not writeable > but when I checked the code I saw that it is. > > Not supporting stable_pages_required attribute is not nice but probably it > isn't widely used. Maybe the deprecation message can even mention to use > the queue attribute? Otherwise the patch looks good to me so feel free to > add: > > Reviewed-by: Jan Kara Thanks. I've fixed the commit log and changed the warning to: dev_warn_once(dev, "the stable_pages_required attribute has been removed. Use the stable_writes queue attribute instead.\n");