From patchwork Thu Aug 4 04:57:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liu Bo X-Patchwork-Id: 9262685 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8C6A060839 for ; Thu, 4 Aug 2016 04:53:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 735BD27DE0 for ; Thu, 4 Aug 2016 04:53:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 655A527FAC; Thu, 4 Aug 2016 04:53:52 +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=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY 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 13B3E27DE0 for ; Thu, 4 Aug 2016 04:53:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752836AbcHDExs (ORCPT ); Thu, 4 Aug 2016 00:53:48 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:26076 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330AbcHDExq (ORCPT ); Thu, 4 Aug 2016 00:53:46 -0400 Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u744rBD8006413 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 4 Aug 2016 04:53:11 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.13.8) with ESMTP id u744rAYk003807 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 4 Aug 2016 04:53:11 GMT Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u744rACM014292; Thu, 4 Aug 2016 04:53:10 GMT Received: from localhost.us.oracle.com (/10.211.47.181) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 03 Aug 2016 21:53:10 -0700 From: Liu Bo To: linux-btrfs@vger.kernel.org Cc: David Sterba Subject: [PATCH] Btrfs: detect corruption when non-root leaf has zero item Date: Wed, 3 Aug 2016 21:57:08 -0700 Message-Id: <1470286628-4123-1-git-send-email-bo.li.liu@oracle.com> X-Mailer: git-send-email 2.5.5 X-Source-IP: userv0022.oracle.com [156.151.31.74] 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 Right now we treat leaf which has zero item as a valid one because we could have an empty tree, that is, a root that is also a leaf without any item, however, in the same case but when the leaf is not a root, we can end up with hitting the BUG_ON(1) in btrfs_extend_item() called by setup_inline_extent_backref(). This makes us check the situation as a corruption if leaf is not its own root. Signed-off-by: Liu Bo --- fs/btrfs/disk-io.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a5a22be..dfaeb96 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -559,8 +559,28 @@ static noinline int check_leaf(struct btrfs_root *root, u32 nritems = btrfs_header_nritems(leaf); int slot; - if (nritems == 0) + if (nritems == 0) { + struct btrfs_root *r; + + key.objectid = btrfs_header_owner(leaf); + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = -1ULL; + + r = btrfs_get_fs_root(root->fs_info, &key, false); + /* + * The only reason we also check NULL here is that during + * open_ctree() some roots has not yet been set up. + */ + if (!IS_ERR_OR_NULL(r)) { + /* if leaf is the root, then it's fine */ + if (leaf->start != btrfs_root_bytenr(&r->root_item)) { + CORRUPT("non-root leaf's nritems is 0", + leaf, root, 0); + return -EIO; + } + } return 0; + } /* Check the 0 item */ if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=