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=-2.2 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 45C97C433DF for ; Wed, 8 Jul 2020 14:42:45 +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 11CBF2078B for ; Wed, 8 Jul 2020 14:42:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kdUjMPgF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 11CBF2078B 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=7Zetmt9rEqZ+0PQXwCV+Z1AL7dkiGUrf+SSae8Xlcm8=; b=kdUjMPgF81K2E7VVyeInbV+x9 CA7Hp8YLrZ3WKMIvZaIrA7mOzmNMT/HjNHOqzjmLaffOh01kMkwbTnwCU+Ds/Rc4V+8qM7CvYKFHq BRn/3XiADUng/OuBZoav3QhwL+ScszUeVIfK0OKdga0C5G/6eAYUxsuK4BMo6aBjZscjSGqLWV4nG gJOkoSByEeqJqhf32ieK3eMlyVWsGl8lACHVHtdRU228MEn4Pg5eTzfW+fjTMbHFZLHpGZERqGdfX qfV9PvHTUEgH3nL5M+wQGqFlFXZr3vN6sYykVeziclbyfRZ4qGOPQ9Sg9JKAGAH8WId4rudmIT4rZ 5m2wnrOBw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtBHN-0008Hf-UE; Wed, 08 Jul 2020 14:42:33 +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 1jtBHK-0008H5-Om for linux-nvme@lists.infradead.org; Wed, 08 Jul 2020 14:42:31 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id CA38E68B05; Wed, 8 Jul 2020 16:42:27 +0200 (CEST) Date: Wed, 8 Jul 2020 16:42:27 +0200 From: Christoph Hellwig To: Anthony Iliopoulos Subject: Re: [PATCH v2 for-5.8-rc 1/6] nvme: fix possible deadlock when I/O is blocked Message-ID: <20200708144227.GA23255@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> <20200707105735.GA16868@technoir> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200707105735.GA16868@technoir> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200708_104231_256726_D26B39CE X-CRM114-Status: GOOD ( 18.25 ) 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 , Sagi Grimberg , linux-nvme@lists.infradead.org, Christoph Hellwig 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, Jul 07, 2020 at 12:57:35PM +0200, Anthony Iliopoulos wrote: > The revalidation is still required there in order to update the blockdev > size when multipath is enabled. With this revert, the behavior regressed > back to before fab7772bfbcf, so the size isn't updated under multipath > when the device is in use (e.g. mounted), it will only be effectively > updated next time it is mounted as a side-effect of blkdev_open on first > opener. This prevents online resizing of filesystems. > > > 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. > > The mpath gendisk doesn't have a revalidate_disk fop indeed, but call to > check_disk_size_change was needed to update its size. Otherwise, the > size change isn't reflected externally to userspace before next mount. > cb224c3af4df doesn't fix this as it skips revalidate and thus also skips > updating the size. > > The issue is that under CONFIG_NVME_MULTIPATH=y the ns->disk becomes a > hidden gendisk (see nvme_set_disk_name) and thus doesn't have a backing > bdev, while ns->head->disk becomes the "visible" one to userspace (with > a backing bdev), and therefore needs its bdev->bd_inode->i_size updated > when resized. > > The following patch seems to be working, although I'm not sufficiently > familiar with the code to tell if this won't cause any other deadlocks > with some confidence: This looks sensible to me. Sagi? _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme