From patchwork Wed Apr 18 22:11:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Allison Henderson X-Patchwork-Id: 10348957 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 F0ACC601D7 for ; Wed, 18 Apr 2018 22:14:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D76EE288D7 for ; Wed, 18 Apr 2018 22:14:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CB172288DD; Wed, 18 Apr 2018 22:14:01 +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=-7.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, 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 39D46288D7 for ; Wed, 18 Apr 2018 22:14:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752586AbeDRWN7 (ORCPT ); Wed, 18 Apr 2018 18:13:59 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:49444 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752463AbeDRWNx (ORCPT ); Wed, 18 Apr 2018 18:13:53 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w3IMBEu2062820 for ; Wed, 18 Apr 2018 22:13:52 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : subject : date : message-id : in-reply-to : references; s=corp-2017-10-26; bh=9YUMlkb9FlBbNqO6CphvIIQ/fXAAvTKQvCWlnLqgnaw=; b=ZNs9gcUvtnSaDnWAxBlenewf3SJLH/yr1SROmDEv9AwBtE1GDir1ucyQy6llaARMM4+y tCq3GUZ9iqNv0v4BFPdd2QM5NKoa9hsmtbfeb6dFzSAEo1HrMCA1/M2JTlHVEidkJ9vW GdvaLYTCFvKvYTVNeG0vpeKi5VNF418JDo3YGPO5hqzcptyxlkaVIMnCkkjHqJbUkAKX wqOUwqXCorvyhevoeMVIdy8uclkh1u+/m7shJfMtPcP0AVOrjBg2UZ2rtRkWqgXq3GXG IbqZcTzl43LO+Arrl4XIbG91piy5iABid4scjPvA26dqxnw+wlbA25WiaP8EDvSaVka+ eA== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2130.oracle.com with ESMTP id 2hdrxnvtrn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 18 Apr 2018 22:13:52 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w3IMDpwZ013245 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 18 Apr 2018 22:13:51 GMT Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w3IMDpCd001400 for ; Wed, 18 Apr 2018 22:13:51 GMT Received: from localhost.localdomain (/72.210.40.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 18 Apr 2018 15:13:50 -0700 From: Allison Henderson To: linux-xfs@vger.kernel.org Subject: [PATCH 10/18] xfs: define parent pointer xattr format Date: Wed, 18 Apr 2018 15:11:18 -0700 Message-Id: <1524089486-22922-11-git-send-email-allison.henderson@oracle.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1524089486-22922-1-git-send-email-allison.henderson@oracle.com> References: <1524089486-22922-1-git-send-email-allison.henderson@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8867 signatures=668698 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1804180201 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Chinner We need to define the parent pointer attribute format before we start adding support for it into all the code that needs to use it. The EA format we will use encodes the following information: name={parent inode #, parent inode generation, dirent offset} value={dirent filename} The inode/gen gives all the information we need to reliably identify the parent without requiring child->parent lock ordering, and allows userspace to do pathname component level reconstruction without the kernel ever needing to verify the parent itself as part of ioctl calls. By using the dirent offset in the EA name, we have a method of knowing the exact parent pointer EA we need to modify/remove in rename/unlink without an unbound EA name search. By keeping the dirent name in the value, we have enough information to be able to validate and reconstruct damaged directory trees. While the diroffset of a filename alone is not unique enough to identify the child, the {diroffset,filename,child_inode} tuple is sufficient. That is, if the diroffset gets reused and points to a different filename, we can detect that from the contents of EA. If a link of the same name is created, then we can check whether it points at the same inode as the parent EA we current have. [achender: rebased, changed __unint32_t to xfs_dir2_dataptr_t, changed p_ino to xfs_ino_t and p_namelen to uint8_t, moved to xfs_da_format for xfs_dir2_dataptr_t] Signed-off-by: Dave Chinner Signed-off-by: Allison Henderson Reviewed-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_da_format.h | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_da_format.h b/fs/xfs/libxfs/xfs_da_format.h index 9bd2e6b..d1c1221 100644 --- a/fs/xfs/libxfs/xfs_da_format.h +++ b/fs/xfs/libxfs/xfs_da_format.h @@ -878,11 +878,35 @@ struct xfs_attr3_rmt_hdr { #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \ ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \ sizeof(struct xfs_attr3_rmt_hdr) : 0)) - /* Number of bytes in a directory block. */ static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp) { return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog); } +/* + * Parent pointer attribute format definition + * + * EA name encodes the parent inode number, generation and the offset of + * the dirent that points to the child inode. The EA value contains the + * same name as the dirent in the parent directory. + */ +struct xfs_parent_name_rec { + __be64 p_ino; + __be32 p_gen; + __be32 p_diroffset; +}; + +/* + * incore version of the above, also contains name pointers so callers + * can pass/obtain all the parent pointer information in a single structure + */ +struct xfs_parent_name_irec { + xfs_ino_t p_ino; + uint32_t p_gen; + xfs_dir2_dataptr_t p_diroffset; + const char *p_name; + uint8_t p_namelen; +}; + #endif /* __XFS_DA_FORMAT_H__ */