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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 F2A97C64E7B for ; Mon, 30 Nov 2020 15:17:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 13BA5206F9 for ; Mon, 30 Nov 2020 15:17:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13BA5206F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 528EC8D0005; Mon, 30 Nov 2020 10:17:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D97F8D0002; Mon, 30 Nov 2020 10:17:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F14D8D0005; Mon, 30 Nov 2020 10:17:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0180.hostedemail.com [216.40.44.180]) by kanga.kvack.org (Postfix) with ESMTP id 279348D0002 for ; Mon, 30 Nov 2020 10:17:45 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id DD700180AD81D for ; Mon, 30 Nov 2020 15:17:44 +0000 (UTC) X-FDA: 77541439248.19.money84_4914304273a2 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 67DFE1ACEA2 for ; Mon, 30 Nov 2020 15:17:44 +0000 (UTC) X-HE-Tag: money84_4914304273a2 X-Filterd-Recvd-Size: 3327 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Mon, 30 Nov 2020 15:17:43 +0000 (UTC) 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 62EECAB63; Mon, 30 Nov 2020 15:17:42 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id CC8061E131B; Mon, 30 Nov 2020 16:17:41 +0100 (CET) Date: Mon, 30 Nov 2020 16:17:41 +0100 From: Jan Kara To: Christoph Hellwig Cc: Jan Kara , Jens Axboe , Tejun Heo , Josef Bacik , Coly Li , Mike Snitzer , Greg Kroah-Hartman , Johannes Thumshirn , dm-devel@redhat.com, Jan Kara , linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Chao Yu Subject: Re: [PATCH 30/45] block: remove the nr_sects field in struct hd_struct Message-ID: <20201130151741.GN11250@quack2.suse.cz> References: <20201128161510.347752-1-hch@lst.de> <20201128161510.347752-31-hch@lst.de> <20201130094421.GD11250@quack2.suse.cz> <20201130145150.GA24694@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201130145150.GA24694@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon 30-11-20 15:51:50, Christoph Hellwig wrote: > On Mon, Nov 30, 2020 at 10:44:21AM +0100, Jan Kara wrote: > > I know I'm like a broken record about this but I still don't understand > > here... I'd expect the new code to be: > > > > if (size == capacity || > > (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) > > return false; > > pr_info("%s: detected capacity change from %lld to %lld\n", > > disk->disk_name, size, capacity); > > + if (!capacity || !size) > > + return false; > > kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); > > return true; > > > > At least that would be equivalent to the original functionality of > > set_capacity_and_notify(). And if you indeed intend to change when > > "RESIZE=1" events are sent, then I'd expect an explanation in the changelog > > why this cannot break userspace (I remember we've already broken some udev > > rules in the past by generating unexpected events and we had to revert > > those changes in the partition code so I'm more careful now). The rest of > > the patch looks good to me. > > I explained that I think the GENHD_FL_UP is the more useful one here in > reply to your last comment. If the size changes to or from 0 during > runtime we probably do want an event. Ah, right, sorry, I missed that. And I agree that it might make sense for changes to / from zero during runtime to send notification. But it still seems as a thin ice with potential to breakage to me. > But I'll add your hunk for now and we can discuss this separately. OK, thanks. With that hunk feel free to add: Reviewed-by: Jan Kara Honza -- Jan Kara SUSE Labs, CR