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=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 23642C67839 for ; Fri, 14 Dec 2018 08:56:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E584620879 for ; Fri, 14 Dec 2018 08:56:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E584620879 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=canonical.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727229AbeLNI4S (ORCPT ); Fri, 14 Dec 2018 03:56:18 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:57498 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726520AbeLNI4S (ORCPT ); Fri, 14 Dec 2018 03:56:18 -0500 Received: from 201-68-129-100.dsl.telesp.net.br ([201.68.129.100] helo=calabresa) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1gXjGX-0006MU-4m; Fri, 14 Dec 2018 08:56:13 +0000 Date: Fri, 14 Dec 2018 06:56:07 -0200 From: Thadeu Lima de Souza Cascardo To: Hannes Reinecke Cc: Christoph Hellwig , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 4/4] block: expose devt for GENHD_FL_HIDDEN disks Message-ID: <20181214085606.GD5321@calabresa> References: <20181206164812.30925-1-cascardo@canonical.com> <20181206164812.30925-5-cascardo@canonical.com> <20181213143218.GA8723@lst.de> <20181213152532.GA5321@calabresa> <35acb1b3-77f5-29cf-b92d-5171f4ad6450@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <35acb1b3-77f5-29cf-b92d-5171f4ad6450@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Dec 14, 2018 at 08:47:20AM +0100, Hannes Reinecke wrote: > On 12/13/18 4:25 PM, Thadeu Lima de Souza Cascardo wrote: > > On Thu, Dec 13, 2018 at 03:32:18PM +0100, Christoph Hellwig wrote: > > > On Thu, Dec 13, 2018 at 10:18:40AM +0100, Hannes Reinecke wrote: > > > > Welll ... this is not just 'lsblk', but more importantly this will force > > > > udev to create _block_ device nodes for the hidden devices, essentially > > > > 'unhide' them. > > > > > > > > Is this what we want? > > > > Christoph? > > > > I thought the entire _point_ of having hidden devices is that the are ... > > > > well ... hidden ... > > > > > > Yes, that is why I really don't like the last two patches. > > > > > > And I've checked back - lsblk actually works just fine at the moment. > > > But it turns out once we create the slave links it stops working, > > > which is a really good argument against the first two patches, which > > > would otherwise seem nice.. > > > > Which is why I have sent the "paths/" patchset in the first place. Because I > > did some homework and read the previous discussion about this, and how lsblk > > failure to behave with slave links led to the revert of the slaves/holders > > patch by Dr. Hannes. > > > But you haven't answered my question: > > Why can't we patch 'lsblk' to provide the required information even with the > current sysfs layout? > I think we could, but with my Ubuntu hat on, after the kernel fix for initramfs-tools, that is, slaves/holders links, the user will get an updated kernel that breaks the current lsblk on Bionic (Ubuntu 18.04). That will require that we backport the lsblk fix, which is not only more work, but there may be users who only update from -security, which is where kernel updates end regularly, but not this lsblk fix. And that kernel update is a regression against that old lsblk version. Cascardo. > Cheers, > > Hannes > -- > Dr. Hannes Reinecke Teamlead Storage & Networking > hare@suse.de +49 911 74053 688 > SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg > GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton > HRB 21284 (AG Nürnberg)