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,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 5CAAAC55ABD for ; Mon, 9 Nov 2020 09:25:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B08620731 for ; Mon, 9 Nov 2020 09:25:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728385AbgKIJZ0 (ORCPT ); Mon, 9 Nov 2020 04:25:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:48186 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726176AbgKIJZZ (ORCPT ); Mon, 9 Nov 2020 04:25:25 -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 CA23CABCC; Mon, 9 Nov 2020 09:25:23 +0000 (UTC) Subject: Re: [PATCH 03/24] nvme: let set_capacity_revalidate_and_notify update the bdev size To: Christoph Hellwig Cc: Jens Axboe , Justin Sanders , Josef Bacik , Ilya Dryomov , Jack Wang , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Minchan Kim , Mike Snitzer , Song Liu , "Martin K. Petersen" , dm-devel@redhat.com, linux-block@vger.kernel.org, drbd-dev@lists.linbit.com, nbd@other.debian.org, ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20201106190337.1973127-1-hch@lst.de> <20201106190337.1973127-4-hch@lst.de> <1d06cdfa-a904-30be-f3ec-08ae2fa85cbd@suse.de> <20201109085340.GB27483@lst.de> From: Hannes Reinecke Message-ID: Date: Mon, 9 Nov 2020 10:25:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201109085340.GB27483@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On 11/9/20 9:53 AM, Christoph Hellwig wrote: > On Mon, Nov 09, 2020 at 08:53:58AM +0100, Hannes Reinecke wrote: >>> index 376096bfc54a83..4e86c9aafd88a7 100644 >>> --- a/drivers/nvme/host/core.c >>> +++ b/drivers/nvme/host/core.c >>> @@ -2053,7 +2053,7 @@ static void nvme_update_disk_info(struct gendisk *disk, >>> capacity = 0; [ .. ] >> Originally nvme multipath would update/change the size of the multipath >> device according to the underlying path devices. >> With this patch the size of the multipath device will _not_ change if there >> is a change on the underlying devices. > > Yes, it will. Take a close look at nvme_update_disk_info and how it is > called. > Okay, then: What would be the correct way of handling a size update for NVMe multipath? Assuming we're getting an AEN for each path signalling the size change (or a controller reset leading to a size change). So if we're updating the size of the multipath device together with the path device at the first AEN/reset we'll end up with the other paths having a different size than the multipath device (and the path we've just been updating). - Do we care, or cross fingers and hope for the best? - Shouldn't we detect the case where we won't get a size update for the other paths, or, indeed, we have a genuine device size mismatch due to a misconfiguration on the target? IE shouldn't we have a flag 'size update pending' for the other paths,, to take them out ouf use temporarily until the other AENs/resets have been processed? Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer