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=unavailable 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 0C8EFC64E7B for ; Mon, 30 Nov 2020 15:18:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B97B720719 for ; Mon, 30 Nov 2020 15:18:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725987AbgK3PSY (ORCPT ); Mon, 30 Nov 2020 10:18:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:59114 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725849AbgK3PSX (ORCPT ); Mon, 30 Nov 2020 10:18:23 -0500 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) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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