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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 3218CC433DB for ; Tue, 26 Jan 2021 09:27:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D69F92310E for ; Tue, 26 Jan 2021 09:27:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389541AbhAZJ1J (ORCPT ); Tue, 26 Jan 2021 04:27:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:35934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731025AbhAYStO (ORCPT ); Mon, 25 Jan 2021 13:49:14 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0B98A2063A; Mon, 25 Jan 2021 18:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611600535; bh=v96sACv011yE0+Z3rLK+GaGBJSBWc3PlydDDvFBYxyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vUgEPmAFkI0BkP08NxQVab4tDkJJCdel9tkSW3GOp681b/QKyOAGxANdxVZV7hjYm FuEVbHNsV403UTExn6uRoHN7nyZME2imbZv0O8pyLdQhgnez/1MbIqkeevfts0+e6q v3gr3w9edNQbKiMVY9rTQ0bi2VUxtFxjxRm1pTr8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hannes Reinecke , Martin Wilck , Christoph Hellwig , Mike Snitzer Subject: [PATCH 5.10 025/199] dm: avoid filesystem lookup in dm_get_dev_t() Date: Mon, 25 Jan 2021 19:37:27 +0100 Message-Id: <20210125183217.318368884@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210125183216.245315437@linuxfoundation.org> References: <20210125183216.245315437@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hannes Reinecke commit 809b1e4945774c9ec5619a8f4e2189b7b3833c0c upstream. This reverts commit 644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()") dm_get_dev_t() is just used to convert an arbitrary 'path' string into a dev_t. It doesn't presume that the device is present; that check will be done later, as the only caller is dm_get_device(), which does a dm_get_table_device() later on, which will properly open the device. So if the path string already _is_ in major:minor representation we can convert it directly, avoiding a recursion into the filesystem to lookup the block device. This avoids a hang in multipath_message() when the filesystem is inaccessible. Fixes: 644bda6f3460 ("dm table: fall back to getting device using name_to_dev_t()") Cc: stable@vger.kernel.org Signed-off-by: Hannes Reinecke Signed-off-by: Martin Wilck Reviewed-by: Christoph Hellwig Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-table.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -370,14 +370,23 @@ int dm_get_device(struct dm_target *ti, { int r; dev_t dev; + unsigned int major, minor; + char dummy; struct dm_dev_internal *dd; struct dm_table *t = ti->table; BUG_ON(!t); - dev = dm_get_dev_t(path); - if (!dev) - return -ENODEV; + if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) { + /* Extract the major/minor numbers */ + dev = MKDEV(major, minor); + if (MAJOR(dev) != major || MINOR(dev) != minor) + return -EOVERFLOW; + } else { + dev = dm_get_dev_t(path); + if (!dev) + return -ENODEV; + } dd = find_device(&t->devices, dev); if (!dd) {