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 B1EDFC433E2 for ; Thu, 17 Sep 2020 09:25:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7EDE5206CA for ; Thu, 17 Sep 2020 09:25:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726241AbgIQJZj (ORCPT ); Thu, 17 Sep 2020 05:25:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:41094 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726298AbgIQJZg (ORCPT ); Thu, 17 Sep 2020 05:25:36 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id CA2C7AC12; Thu, 17 Sep 2020 09:25:58 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id BC6F61E12E1; Thu, 17 Sep 2020 11:25:24 +0200 (CEST) Date: Thu, 17 Sep 2020 11:25:24 +0200 From: Jan Kara To: Christoph Hellwig Cc: 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: <20200917092524.GC7347@quack2.suse.cz> References: <20200910144833.742260-1-hch@lst.de> <20200910144833.742260-11-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200910144833.742260-11-hch@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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 Honza -- Jan Kara SUSE Labs, CR