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, 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 9350DC4338F for ; Wed, 28 Jul 2021 06:54:28 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B01A060EBB for ; Wed, 28 Jul 2021 06:54:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B01A060EBB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-591-lcfespMZNuK-ui7P3JVaUA-1; Wed, 28 Jul 2021 02:54:25 -0400 X-MC-Unique: lcfespMZNuK-ui7P3JVaUA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5EE24801AE7; Wed, 28 Jul 2021 06:54:20 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C809A1007606; Wed, 28 Jul 2021 06:54:18 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id ED0024BB7C; Wed, 28 Jul 2021 06:54:15 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 16S6sDr7003550 for ; Wed, 28 Jul 2021 02:54:14 -0400 Received: by smtp.corp.redhat.com (Postfix) id CDF632167807; Wed, 28 Jul 2021 06:54:13 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast01.extmail.prod.ext.rdu2.redhat.com [10.11.55.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C95FF21677FB for ; Wed, 28 Jul 2021 06:54:10 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7CDEE858286 for ; Wed, 28 Jul 2021 06:54:10 +0000 (UTC) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-564-LcdFC1l9NNuO-ktAU207IQ-1; Wed, 28 Jul 2021 02:54:06 -0400 X-MC-Unique: LcdFC1l9NNuO-ktAU207IQ-1 Received: by verein.lst.de (Postfix, from userid 2407) id 683BD67357; Wed, 28 Jul 2021 08:54:03 +0200 (CEST) Date: Wed, 28 Jul 2021 08:54:03 +0200 From: Christoph Hellwig To: Mike Snitzer Message-ID: <20210728065403.GA4815@lst.de> References: <20210725055458.29008-1-hch@lst.de> <20210725055458.29008-5-hch@lst.de> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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 2.78 on 10.11.54.6 X-loop: dm-devel@redhat.com Cc: Jens Axboe , linux-block@vger.kernel.org, dm-devel@redhat.com, Christoph Hellwig Subject: Re: [dm-devel] [PATCH 4/8] block: support delayed holder registration 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 2.84 on 10.5.11.22 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 Tue, Jul 27, 2021 at 12:06:04PM -0400, Mike Snitzer wrote: > This header starts to shine some light on what is motivating this > series by touching on "all kinds of bad side effects" being fixed. > Any chance you could elaborate what you've noticed/found/hit? The proble mis that it leaves the queue in a weird half state. The normal states for a gendisk are: 1) allocated (after *alloc_disk) 2) registered (after add_disk*) 3) unregistered (after del_gendisk) the delayed queue registration adds a weird half state where it is sort of registered, except for in sysfs and the elevator. I have some pretty big changes between how the disk and queue interact that tripped over it, but even right now code has to be very careful in the takedown path to deal with the half-initialized disks. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel 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, 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 D7462C4338F for ; Wed, 28 Jul 2021 06:54:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB89660EBB for ; Wed, 28 Jul 2021 06:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232540AbhG1GyG (ORCPT ); Wed, 28 Jul 2021 02:54:06 -0400 Received: from verein.lst.de ([213.95.11.211]:52571 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232798AbhG1GyG (ORCPT ); Wed, 28 Jul 2021 02:54:06 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 683BD67357; Wed, 28 Jul 2021 08:54:03 +0200 (CEST) Date: Wed, 28 Jul 2021 08:54:03 +0200 From: Christoph Hellwig To: Mike Snitzer Cc: Christoph Hellwig , Jens Axboe , dm-devel@redhat.com, linux-block@vger.kernel.org Subject: Re: [PATCH 4/8] block: support delayed holder registration Message-ID: <20210728065403.GA4815@lst.de> References: <20210725055458.29008-1-hch@lst.de> <20210725055458.29008-5-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jul 27, 2021 at 12:06:04PM -0400, Mike Snitzer wrote: > This header starts to shine some light on what is motivating this > series by touching on "all kinds of bad side effects" being fixed. > Any chance you could elaborate what you've noticed/found/hit? The proble mis that it leaves the queue in a weird half state. The normal states for a gendisk are: 1) allocated (after *alloc_disk) 2) registered (after add_disk*) 3) unregistered (after del_gendisk) the delayed queue registration adds a weird half state where it is sort of registered, except for in sysfs and the elevator. I have some pretty big changes between how the disk and queue interact that tripped over it, but even right now code has to be very careful in the takedown path to deal with the half-initialized disks.