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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 151CBC433E0 for ; Wed, 24 Jun 2020 06:57:55 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 D58042072E for ; Wed, 24 Jun 2020 06:57:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="GZI5qb5v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D58042072E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=suz0xIwxiTiw6bufJ15SgZEqqd27zJFsGTMppHb5/VA=; b=GZI5qb5vef3niB80gJQT1hEEt zfdubdRWbs9hWWHWZwsCk8cEYeJbHA9P4IU2ToNaHDI/cchfjdHJCdhvHXazmmYFdI4bBFE7EuHuD m6jyD6zJOuZogmCCNJOZ8ACdJXULLYlS70kUHNPEQkKnlEdrY+E84d07DKoXgwUn/eJs5ePYwCNqp rZ8gzi0TfiDR1WK8WqxzpUcZXnc/DbAA+AfvIifZCME6S/RB5AdDXJ1EbGhjb3zNCEgRHKKXXcBr4 iiWbvvIq/BgNn/zMTQjeB1NKl4mIYlZS+4whEP2BJumbud+qCQsnpcj8D/sIBP8QUKLrcX0VjFhqU bbSGBmVIA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jnzM0-0001uw-2G; Wed, 24 Jun 2020 06:57:52 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jnzLw-0001st-3P for linux-nvme@lists.infradead.org; Wed, 24 Jun 2020 06:57:48 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 8EC3C68AEF; Wed, 24 Jun 2020 08:57:45 +0200 (CEST) Date: Wed, 24 Jun 2020 08:57:45 +0200 From: Christoph Hellwig To: Sagi Grimberg Subject: Re: [PATCH v2 for-5.8-rc 1/6] nvme: fix possible deadlock when I/O is blocked Message-ID: <20200624065745.GA18207@lst.de> References: <20200624001853.5408-1-sagi@grimberg.me> <20200624001853.5408-2-sagi@grimberg.me> <20200624062902.GA17594@lst.de> <84583b2e-d59b-01bc-1737-5db107999d84@grimberg.me> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <84583b2e-d59b-01bc-1737-5db107999d84@grimberg.me> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Keith Busch , Anton Eidelman , Christoph Hellwig , linux-nvme@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Jun 23, 2020 at 11:54:31PM -0700, Sagi Grimberg wrote: > >>> Revert fab7772bfbcf ("nvme-multipath: revalidate nvme_ns_head gendisk >>> in nvme_validate_ns") >>> >>> When adding a new namespace to the head disk (via nvme_mpath_set_live) >>> we will see partition scan which triggers I/O on the mpath device node. >>> This process will usually be triggered from the scan_work which holds >>> the scan_lock. If I/O blocks (if we got ana change currently have only >>> available paths but none are accessible) this can deadlock on the head >>> disk bd_mutex as both partition scan I/O takes it, and head disk revalidation >>> takes it to check for resize (also triggered from scan_work on a different >>> path). See trace [1]. >>> >>> This is no longer needed since commit cb224c3af4df ("nvme: Convert to >>> use set_capacity_revalidate_and_notify") which already updates resize >>> info without unnecessarily revalidating the disk. >> >> Did you look if any other revalidation gets skipped this way? E.g. >> LBA size change? >> >> From purely the size POV this looks good, though. > > The only reason the revalidate was added was to update on a size change, > which is redundant. > > And if you look at revalidate, it only calls fops->revalidate_disk > (which is a noop in the mpath device) and checks the size change. Please add this blurb to the changelog for the next version. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme