From patchwork Wed Feb 13 14:26:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Thumshirn X-Patchwork-Id: 10810023 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 42254922 for ; Wed, 13 Feb 2019 14:26:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 306FE2074F for ; Wed, 13 Feb 2019 14:26:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2450D2D2BD; Wed, 13 Feb 2019 14:26:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B083E2074F for ; Wed, 13 Feb 2019 14:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392147AbfBMO0V (ORCPT ); Wed, 13 Feb 2019 09:26:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:53810 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388763AbfBMO0V (ORCPT ); Wed, 13 Feb 2019 09:26:21 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6F2A6AC69; Wed, 13 Feb 2019 14:26:20 +0000 (UTC) From: Johannes Thumshirn To: David Sterba Cc: Linux BTRFS Mailinglist , Johannes Thumshirn , Liu Bo Subject: [PATCH] btrfs: ensure that a DUP block group has exactly two stripes Date: Wed, 13 Feb 2019 15:26:02 +0100 Message-Id: <20190213142602.20436-1-jthumshirn@suse.de> X-Mailer: git-send-email 2.16.4 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We recently had a customer issue with a corrupted filesystem. When trying to mount this image btrfs panicked with a division by zero in calc_stripe_length(). The corrupt chunk had a 'num_stripes' value of 1. calc_stripe_length() takes this value and divides it by the number of copies the RAID profile is expected to have to calculate the amount of data stripes. As a DUP profile is expected to have 2 copies this division resulted in 1/2 = 0. Later then the 'data_stripes' variable is used as a divisor in the stripe length calculation which results in a division by 0 and thus a kernel panic. When encountering a filesystem with a DUP block group and a 'num_stripes' value unequal to 2, refuse mounting as the image is corrupted and will lead to unexpected behaviour. Fixes: e06cd3dd7cea ("Btrfs: add validadtion checks for chunk loading") Cc: Liu Bo Signed-off-by: Johannes Thumshirn Reviewed-by: Nikolay Borisov Reviewed-by: Qu Wenruo --- fs/btrfs/volumes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 03f223aa7194..b40cc7c830f4 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6794,7 +6794,7 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info, (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) || (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) || (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) || - (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) || + (type & BTRFS_BLOCK_GROUP_DUP && num_stripes != 2) || ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 && num_stripes != 1)) { btrfs_err(fs_info,