From patchwork Wed Oct 17 22:44:49 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: 10646307 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 4BC6F3C13 for ; Wed, 17 Oct 2018 22:45:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3D25D288CA for ; Wed, 17 Oct 2018 22:45:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1F6A6288E4; Wed, 17 Oct 2018 22:45:42 +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=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from userp2120.oracle.com (userp2120.oracle.com [156.151.31.85]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A8DED288C7 for ; Wed, 17 Oct 2018 22:45:41 +0000 (UTC) Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9HMhjqA189027; Wed, 17 Oct 2018 22:45:23 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : date : message-id : in-reply-to : references : mime-version : cc : subject : list-id : list-unsubscribe : list-archive : list-post : list-help : list-subscribe : content-type : content-transfer-encoding : sender; s=corp-2018-07-02; bh=IMC5NAVhBRDbKE5uv5cltcgw9pmRHVZEj/G7M9C2XRQ=; b=1sH2c9KAh00MvlhgStlls59S+PqysT/OJuOdWoCp0vQbn4GuwnlozLi4FWMMLXG8+Qez j0FquSE04uCkvuUnm8SDHzLD3CG4rsWYb2hyrDYFBnfkFtGQH1Lwnt7WMpXhlVfyGTX+ YfM8b/uP/pvkWOAfpwWPJH525+u4a+5WRYxCBbAQZxRvrfpJII3vJJW70Kpu0tKFOknC JKp8dRwX1v20MVNfZoSKryBYk2fF4ypR2+B1fBnbT1wwJ6uGPsfYOqClV+AcSuIoEwtA LQ4P9h7yW1uDa8htS68wesJdQqK0naDLYvyDO23QQb+RM88zmH/VB4poqVz9kBLzVFMU Lg== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2120.oracle.com with ESMTP id 2n39brhp2n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Oct 2018 22:45:23 +0000 Received: from oss.oracle.com (oss-old-reserved.oracle.com [137.254.22.2]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w9HMjMUs009686 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 17 Oct 2018 22:45:22 GMT Received: from localhost ([127.0.0.1] helo=lb-oss.oracle.com) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1gCuZ8-0007lv-1Z; Wed, 17 Oct 2018 15:45:22 -0700 Received: from aserv0022.oracle.com ([141.146.126.234]) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1gCuYd-0007gM-SD for ocfs2-devel@oss.oracle.com; Wed, 17 Oct 2018 15:44:51 -0700 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9HMip3x000659 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Oct 2018 22:44:51 GMT Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w9HMipBk014640; Wed, 17 Oct 2018 22:44:51 GMT Received: from localhost (/10.159.132.177) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 17 Oct 2018 15:44:51 -0700 From: "Darrick J. Wong" To: david@fromorbit.com, darrick.wong@oracle.com Date: Wed, 17 Oct 2018 15:44:49 -0700 Message-ID: <153981628984.5568.13713064343145585532.stgit@magnolia> In-Reply-To: <153981625504.5568.2708520119290577378.stgit@magnolia> References: <153981625504.5568.2708520119290577378.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 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, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: [Ocfs2-devel] [PATCH 05/29] vfs: avoid problematic remapping requests into partial EOF block X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9049 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810170188 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);