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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 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 In-Reply-To: <20201130145150.GA24694@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-loop: dm-devel@redhat.com Cc: Jens Axboe , Chao Yu , Jan Kara , Mike Snitzer , linux-mm@kvack.org, Greg Kroah-Hartman , Jan Kara , Josef Bacik , Coly Li , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, linux-mtd@lists.infradead.org, Johannes Thumshirn , Tejun Heo , linux-bcache@vger.kernel.org Subject: Re: [dm-devel] [PATCH 30/45] block: remove the nr_sects field in struct hd_struct X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel