From patchwork Mon Mar 16 13:07:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Bin X-Patchwork-Id: 11440353 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8530290 for ; Mon, 16 Mar 2020 13:00:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FFD92074D for ; Mon, 16 Mar 2020 13:00:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731066AbgCPNAT (ORCPT ); Mon, 16 Mar 2020 09:00:19 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:45398 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731062AbgCPNAT (ORCPT ); Mon, 16 Mar 2020 09:00:19 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id E75A1348A51EAB71F376; Mon, 16 Mar 2020 21:00:06 +0800 (CST) Received: from huawei.com (10.90.53.225) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Mon, 16 Mar 2020 20:59:55 +0800 From: Zheng Bin To: , , , , CC: , Subject: [PATCH 2/2] xfs: avoid f_bfree overflow Date: Mon, 16 Mar 2020 21:07:08 +0800 Message-ID: <1584364028-122886-3-git-send-email-zhengbin13@huawei.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1584364028-122886-1-git-send-email-zhengbin13@huawei.com> References: <1584364028-122886-1-git-send-email-zhengbin13@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.90.53.225] X-CFilter-Loop: Reflected Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org If fdblocks < mp->m_alloc_set_aside, statp->f_bfree will overflow. When we df -h /mnt(xfs mount point), will show this: Filesystem Size Used Avail Use% Mounted on /dev/loop0 13M -64Z -32K 100% /mnt Make sure statp->f_bfree does not underflow. PS: add fdblocks check in mount. Signed-off-by: Zheng Bin --- fs/xfs/xfs_mount.c | 6 ++++++ fs/xfs/xfs_super.c | 3 ++- 2 files changed, 8 insertions(+), 1 deletion(-) -- 2.7.4 diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index dc41801..a223af4 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -816,6 +816,12 @@ xfs_mountfs( if (error) goto out_log_dealloc; + if (sbp->sb_fdblocks < mp->m_alloc_set_aside) { + xfs_alert(mp, "Corruption detected. Please run xfs_repair."); + error = -EFSCORRUPTED; + goto out_log_dealloc; + } + /* * Get and sanity-check the root inode. * Save the pointer to it in the mount structure. diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 2094386..9dcf772 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -755,7 +755,8 @@ xfs_fs_statfs( statp->f_blocks = sbp->sb_dblocks - lsize; spin_unlock(&mp->m_sb_lock); - statp->f_bfree = fdblocks - mp->m_alloc_set_aside; + /* make sure statp->f_bfree does not underflow */ + statp->f_bfree = max_t(int64_t, fdblocks - mp->m_alloc_set_aside, 0); statp->f_bavail = statp->f_bfree; fakeinos = XFS_FSB_TO_INO(mp, statp->f_bfree);