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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 86CE5C4338F for ; Thu, 19 Aug 2021 18:06:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63D0560C3E for ; Thu, 19 Aug 2021 18:06:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229520AbhHSSGj (ORCPT ); Thu, 19 Aug 2021 14:06:39 -0400 Received: from verein.lst.de ([213.95.11.211]:38473 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229465AbhHSSGi (ORCPT ); Thu, 19 Aug 2021 14:06:38 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 8BDED6736F; Thu, 19 Aug 2021 20:05:59 +0200 (CEST) Date: Thu, 19 Aug 2021 20:05:59 +0200 From: Christoph Hellwig To: Mike Snitzer Cc: Christoph Hellwig , Jens Axboe , dm-devel@redhat.com, linux-block@vger.kernel.org, Tushar Sugandhi Subject: Re: holders not working properly, regression [was: Re: use regular gendisk registration in device mapper v2] Message-ID: <20210819180559.GA14001@lst.de> References: <20210804094147.459763-1-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 Manually reverting "block: remove the extra kobject reference in bd_link_disk_holder" as show below fixed the issue for me. I'll spend some more time tomorrow trying to fully understan the life time rules tomorrow before sending a patch, though. --- >From 6b94f5435900d23769db8d07ff47415aab4ac63e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 19 Aug 2021 20:01:43 +0200 Subject: Revert "block: remove the extra kobject reference in bd_link_disk_holder" This reverts commit fbd9a39542ecdd2ade55869c13856b2590db3df8. --- block/holder.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/holder.c b/block/holder.c index 4568cc4f6827..ecbc6941e7d8 100644 --- a/block/holder.c +++ b/block/holder.c @@ -106,6 +106,12 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) } list_add(&holder->list, &disk->slave_bdevs); + /* + * bdev could be deleted beneath us which would implicitly destroy + * the holder directory. Hold on to it. + */ + kobject_get(bdev->bd_holder_dir); + out_unlock: mutex_unlock(&disk->open_mutex); return ret; @@ -138,6 +144,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { if (disk->slave_dir) __unlink_disk_holder(bdev, disk); + kobject_put(bdev->bd_holder_dir); list_del_init(&holder->list); kfree(holder); } -- 2.30.2