From patchwork Thu Dec 26 13:47:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 11310513 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 4F809184C for ; Thu, 26 Dec 2019 13:48:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3847920828 for ; Thu, 26 Dec 2019 13:48:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726074AbfLZNsJ (ORCPT ); Thu, 26 Dec 2019 08:48:09 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:8197 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726596AbfLZNsJ (ORCPT ); Thu, 26 Dec 2019 08:48:09 -0500 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id E60EB48045FF6C5EA907; Thu, 26 Dec 2019 21:48:06 +0800 (CST) Received: from huawei.com (10.175.124.28) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.439.0; Thu, 26 Dec 2019 21:47:56 +0800 From: yu kuai To: , , , , , CC: , , , , , Subject: [PATCH 2/2] xfs: fix stale data exposure problem when punch hole, collapse range or zero range across a delalloc extent Date: Thu, 26 Dec 2019 21:47:21 +0800 Message-ID: <20191226134721.43797-3-yukuai3@huawei.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20191226134721.43797-1-yukuai3@huawei.com> References: <20191226134721.43797-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org In xfs_file_fallocate, when punch hole, zero range or collapse range is performed, xfs_fulsh_unmap_range() need to be called first. However, xfs_map_blocks will convert the whole extent to real, even if there are some blocks not related. Furthermore, the unrelated blocks will hold stale data since xfs_fulsh_unmap_range didn't flush the correspond dirty pages to disk. In this case, if user shutdown file system through xfsioctl with cmd 'XFS_IOC_GOINGDOWN' and arg 'XFS_FSOP_GOING_FLAGS_LOGFLUSH'. All the completed transactions will be flushed to disk, while dirty pages will never be flushed to disk. And after remount, the file will hold stale data. Fix the problem by spliting delalloc extent before xfs_flush_unmap_range is called. Signed-off-by: yu kuai Reported-by: kbuild test robot Reported-by: kernel test robot --- fs/xfs/xfs_file.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index c93250108952..5398102feec9 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -786,6 +786,50 @@ xfs_break_layouts( return error; } +int +try_split_da_extent( + struct xfs_inode *ip, + loff_t offset, + loff_t len) +{ + struct xfs_mount *mp = ip->i_mount; + xfs_fileoff_t start = XFS_B_TO_FSBT(mp, offset); + xfs_fileoff_t end = XFS_B_TO_FSBT(mp, offset + len - 1); + struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK); + struct xfs_iext_cursor cur; + struct xfs_bmbt_irec imap; + int error; + + /* + * if start belong to a delalloc extent and it's not the first block, + * split the extent at start. + */ + if (xfs_iext_lookup_extent(ip, ifp, start, &cur, &imap) && + imap.br_startblock != HOLESTARTBLOCK && + isnullstartblock(imap.br_startblock) && + start > imap.br_startoff) { + error = xfs_bmap_split_da_extent(ip, start); + if (error) + return error; + ip->i_d.di_nextents--; + } + + /* + * if end + 1 belong to a delalloc extent and it's not the first block, + * split the extent at end + 1. + */ + if (xfs_iext_lookup_extent(ip, ifp, end + 1, &cur, &imap) && + imap.br_startblock != HOLESTARTBLOCK && + isnullstartblock(imap.br_startblock) && + end + 1 > imap.br_startoff) { + error = xfs_bmap_split_da_extent(ip, end + 1); + if (error) + return error; + ip->i_d.di_nextents--; + } + + return 0; +} #define XFS_FALLOC_FL_SUPPORTED \ (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ @@ -842,6 +886,9 @@ xfs_file_fallocate( */ if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE | FALLOC_FL_COLLAPSE_RANGE)) { + error = try_split_da_extent(ip, offset, len); + if (error) + goto out_unlock; error = xfs_flush_unmap_range(ip, offset, len); if (error) goto out_unlock;