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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, 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 A3C7BC433E6 for ; Tue, 16 Feb 2021 11:49:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69A9E64DA8 for ; Tue, 16 Feb 2021 11:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230106AbhBPLtm (ORCPT ); Tue, 16 Feb 2021 06:49:42 -0500 Received: from verein.lst.de ([213.95.11.211]:40978 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230360AbhBPLrY (ORCPT ); Tue, 16 Feb 2021 06:47:24 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 5738667373; Tue, 16 Feb 2021 12:46:24 +0100 (CET) Date: Tue, 16 Feb 2021 12:46:24 +0100 From: Christoph Hellwig To: Mike Snitzer Cc: Christoph Hellwig , Jens Axboe , Justin Sanders , Josef Bacik , Ilya Dryomov , Jack Wang , "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Stefan Hajnoczi , Konrad Rzeszutek Wilk , Roger Pau =?iso-8859-1?Q?Monn=E9?= , Minchan Kim , Song Liu , "Martin K. Petersen" , device-mapper development , linux-block , 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 , Hannes Reinecke Subject: Re: [PATCH 12/78] dm: use set_capacity_and_notify Message-ID: <20210216114624.GA1221@lst.de> References: <20201116145809.410558-1-hch@lst.de> <20201116145809.410558-13-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-raid@vger.kernel.org On Fri, Feb 12, 2021 at 10:45:32AM -0500, Mike Snitzer wrote: > On Mon, Nov 16, 2020 at 10:05 AM Christoph Hellwig wrote: > > > > Use set_capacity_and_notify to set the size of both the disk and block > > device. This also gets the uevent notifications for the resize for free. > > > > Signed-off-by: Christoph Hellwig > > Reviewed-by: Hannes Reinecke > > --- > > drivers/md/dm.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > > index c18fc25485186d..62ad44925e73ec 100644 > > --- a/drivers/md/dm.c > > +++ b/drivers/md/dm.c > > @@ -1971,8 +1971,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, > > if (size != dm_get_size(md)) > > memset(&md->geometry, 0, sizeof(md->geometry)); > > > > - set_capacity(md->disk, size); > > - bd_set_nr_sectors(md->bdev, size); > > + set_capacity_and_notify(md->disk, size); > > > > dm_table_event_callback(t, event_callback, md); > > > > Not yet pinned down _why_ DM is calling set_capacity_and_notify() with > a size of 0 but, when running various DM regression tests, I'm seeing > a lot of noise like: > > [ 689.240037] dm-2: detected capacity change from 2097152 to 0 > > Is this pr_info really useful? Should it be moved to below: if > (!capacity || !size) so that it only prints if a uevent is sent? In general I suspect such a size change might be interesting to users if it e.g. comes from a remote event. So I'd be curious why this happens with DM, and if we can detect some higher level gendisk state to supress it if it is indeed spurious.