From patchwork Tue Apr 5 07:27:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557902 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2480C43217 for ; Tue, 5 Apr 2022 08:38:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235518AbiDEIjz (ORCPT ); Tue, 5 Apr 2022 04:39:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234465AbiDEIZW (ORCPT ); Tue, 5 Apr 2022 04:25:22 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 379B4640E; Tue, 5 Apr 2022 01:20:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 9BB12CE1BFD; Tue, 5 Apr 2022 08:20:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE50BC385A0; Tue, 5 Apr 2022 08:20:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649146839; bh=/o9fNK5bqR6kftZu/EOWCZug70FUBtUshjvzfQYlfQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SdQMgXma0xOYGFdk6akLh3eXFckUSsBE3Op1FYvVRba7Pyonh4X/TiNNlim1V3NiD SqOknx/K5YzhS9t1cUjIQ4z7K+11vuOsBHWnMpxQlV1rUTNgELvWMmIMYtrXS9BPtd BuACIraGmkejl9BF6JaCrksbuEKb1clVpgC1lofA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , Anand Jain , David Sterba , Sasha Levin Subject: [PATCH 5.17 0880/1126] btrfs: harden identification of a stale device Date: Tue, 5 Apr 2022 09:27:07 +0200 Message-Id: <20220405070433.360745294@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Anand Jain [ Upstream commit 770c79fb65506fc7c16459855c3839429f46cb32 ] Identifying and removing the stale device from the fs_uuids list is done by btrfs_free_stale_devices(). btrfs_free_stale_devices() in turn depends on device_path_matched() to check if the device appears in more than one btrfs_device structure. The matching of the device happens by its path, the device path. However, when device mapper is in use, the dm device paths are nothing but a link to the actual block device, which leads to the device_path_matched() failing to match. Fix this by matching the dev_t as provided by lookup_bdev() instead of plain string compare of the device paths. Reported-by: Josef Bacik Signed-off-by: Anand Jain Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/volumes.c | 45 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b07d382d53a8..24e559d90b6a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -534,15 +534,48 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder, return ret; } -static bool device_path_matched(const char *path, struct btrfs_device *device) +/* + * Check if the device in the path matches the device in the given struct device. + * + * Returns: + * true If it is the same device. + * false If it is not the same device or on error. + */ +static bool device_matched(const struct btrfs_device *device, const char *path) { - int found; + char *device_name; + dev_t dev_old; + dev_t dev_new; + int ret; + + /* + * If we are looking for a device with the matching dev_t, then skip + * device without a name (a missing device). + */ + if (!device->name) + return false; + + device_name = kzalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL); + if (!device_name) + return false; rcu_read_lock(); - found = strcmp(rcu_str_deref(device->name), path); + scnprintf(device_name, BTRFS_PATH_NAME_MAX, "%s", rcu_str_deref(device->name)); rcu_read_unlock(); - return found == 0; + ret = lookup_bdev(device_name, &dev_old); + kfree(device_name); + if (ret) + return false; + + ret = lookup_bdev(path, &dev_new); + if (ret) + return false; + + if (dev_old == dev_new) + return true; + + return false; } /* @@ -575,9 +608,7 @@ static int btrfs_free_stale_devices(const char *path, &fs_devices->devices, dev_list) { if (skip_device && skip_device == device) continue; - if (path && !device->name) - continue; - if (path && !device_path_matched(path, device)) + if (path && !device_matched(device, path)) continue; if (fs_devices->opened) { /* for an already deleted device return 0 */