From patchwork Tue Oct 16 03:10:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 10642767 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 384593B73 for ; Tue, 16 Oct 2018 03:10:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2839029883 for ; Tue, 16 Oct 2018 03:10:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1C3672988C; Tue, 16 Oct 2018 03:10:53 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable 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 AEA79298A8 for ; Tue, 16 Oct 2018 03:10:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727193AbeJPK64 (ORCPT ); Tue, 16 Oct 2018 06:58:56 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:48832 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727005AbeJPK64 (ORCPT ); Tue, 16 Oct 2018 06:58:56 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9G38WEU053380; Tue, 16 Oct 2018 03:10:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : from : to : cc : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=SHexZ7j4NahuPkzJw7xdjRTs2Ez8K2Od8tzKdBj+sBY=; b=H0ukRTz8fmbz+UNjUlWTynWGl8FmMJlmvVkeCt3iD2KS+3j13JoPAZ6DxpdIPgbwnhAi 4SiVZpLOD6yNMXxBGPvKgCRJUsSHv9fqyoZ6taQJfBJLBSk6GnfNaD8M/Zkf3KEpgHFr Bo5cYCuQ97yAJWM5URMC/34YVkaUnIcq6HKXWT0WTeKWL9cB1qVaz828uLlbV9raHXdT rqsqRRp0cCgp5CkqKQ/k0FxAYXw6rhZLudyGP9v3Jdk1vA5AXpbakT36k1MnIjDxBxjw XJ61fLF8ccZ4JRT+cGgHGRpSXgi9qBcK6co9110eKq26CfNLQn+WAAFWbHkLnuCOWHGW Lg== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by aserp2120.oracle.com with ESMTP id 2n38npwuw6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Oct 2018 03:10:39 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9G3AdSi010257 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Oct 2018 03:10:39 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w9G3Advo002407; Tue, 16 Oct 2018 03:10:39 GMT Received: from localhost (/10.159.227.150) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 15 Oct 2018 20:10:39 -0700 Subject: [PATCH 06/26] vfs: avoid problematic remapping requests into partial EOF block From: "Darrick J. Wong" To: david@fromorbit.com, darrick.wong@oracle.com Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , ocfs2-devel@oss.oracle.com Date: Mon, 15 Oct 2018 20:10:37 -0700 Message-ID: <153965943770.1256.12251598427341926061.stgit@magnolia> In-Reply-To: <153965939489.1256.7400115244528045860.stgit@magnolia> References: <153965939489.1256.7400115244528045860.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9047 signatures=668706 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=786 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810160026 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Darrick J. Wong A deduplication data corruption is exposed in XFS and btrfs. It is caused by extending the block match range to include the partial EOF block, but then allowing unknown data beyond EOF to be considered a "match" to data in the destination file because the comparison is only made to the end of the source file. This corrupts the destination file when the source extent is shared with it. The VFS remapping prep functions only support whole block dedupe, but we still need to appear to support whole file dedupe correctly. Hence if the dedupe request includes the last block of the souce file, don't include it in the actual dedupe operation. If the rest of the range dedupes successfully, then reject the entire request. A subsequent patch will enable us to shorten dedupe requests correctly. When reflinking sub-file ranges, a data corruption can occur when the source file range includes a partial EOF block. This shares the unknown data beyond EOF into the second file at a position inside EOF, exposing stale data in the second file. If the reflink request includes the last block of the souce file, only proceed with the reflink operation if it lands at or past the destination file's current EOF. If it lands within the destination file EOF, reject the entire request with -EINVAL and make the caller go the hard way. A subsequent patch will enable us to shorten reflink requests correctly. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/read_write.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index 2456da3f8a41..0f0a6efdd502 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1708,6 +1708,34 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write) return security_file_permission(file, write ? MAY_WRITE : MAY_READ); } +/* + * Ensure that we don't remap a partial EOF block in the middle of something + * else. Assume that the offsets have already been checked for block + * alignment. + * + * For deduplication we always scale down to the previous block because we + * can't meaningfully compare post-EOF contents. + * + * For clone we only link a partial EOF block above the destination file's EOF. + */ +static int generic_remap_check_len(struct inode *inode_in, + struct inode *inode_out, + loff_t pos_out, + u64 *len, + bool is_dedupe) +{ + u64 blkmask = i_blocksize(inode_in) - 1; + + if ((*len & blkmask) == 0) + return 0; + + if (is_dedupe) + *len &= ~blkmask; + else if (pos_out + *len < i_size_read(inode_out)) + return -EINVAL; + + return 0; +} /* * Check that the two inodes are eligible for cloning, the ranges make @@ -1787,6 +1815,11 @@ int vfs_clone_file_prep(struct file *file_in, loff_t pos_in, return -EBADE; } + ret = generic_remap_check_len(inode_in, inode_out, pos_out, len, + is_dedupe); + if (ret) + return ret; + return 1; } EXPORT_SYMBOL(vfs_clone_file_prep);