From patchwork Sun Jun 10 05:07:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Allison Henderson X-Patchwork-Id: 10456543 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 DD4146020F for ; Sun, 10 Jun 2018 05:10:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CE301251F9 for ; Sun, 10 Jun 2018 05:10:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C30AD25EA6; Sun, 10 Jun 2018 05:10:18 +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 5B2D4251F9 for ; Sun, 10 Jun 2018 05:10:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932157AbeFJFKR (ORCPT ); Sun, 10 Jun 2018 01:10:17 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:33962 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753675AbeFJFKO (ORCPT ); Sun, 10 Jun 2018 01:10:14 -0400 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 w5A56ndP095021 for ; Sun, 10 Jun 2018 05:10:14 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=7YbiyakXkXNpIyiC6pbK3+YlYklT16c/6eidWuCSthM=; b=MuYjMy003pu0HEJ7b3aGJ93WfCXuHSFVsbIwSgrUN7FNIGJJ6M+kbLIaBNHhXz+9pGaA TXprDVqggNnq2vc0jspWICDB8z5W60PCK9skS/O8XSM74WhlT/1x2216tLEi9z9dJ8z3 /81F+vS41kXCHg0gVFFu5cQCbC8rq5pKrbX/CDEVD/A9S7KPnEY2Rv/tTaZ8y2HKWcnB ZDZlbxhE9wmWCoQ9kThnQlQ+vjYhZ496ryW81rxKM+Q4EwgUWvS6QcXlfbV4ecSTOQaM Z7A9FaO1pPXGHglI5G7c8mdg8Bd5TAsnHCxcqwQLu/vkHkeorBBFs7wyGWpw/v9180CY ZA== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2jg7hwstd2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sun, 10 Jun 2018 05:10:14 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5A5AD6M004564 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sun, 10 Jun 2018 05:10:13 GMT Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5A5ADnk001506 for ; Sun, 10 Jun 2018 05:10:13 GMT Received: from localhost.localdomain (/72.210.40.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 09 Jun 2018 22:10:13 -0700 From: Allison Henderson To: linux-xfs@vger.kernel.org Subject: [PATCH v2 13/27] xfsprogs: define parent pointer xattr format Date: Sat, 9 Jun 2018 22:07:38 -0700 Message-Id: <1528607272-11122-14-git-send-email-allison.henderson@oracle.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1528607272-11122-1-git-send-email-allison.henderson@oracle.com> References: <1528607272-11122-1-git-send-email-allison.henderson@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8919 signatures=668702 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=8.0.1-1805220000 definitions=main-1806100059 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 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 Signed-off-by: Allison Henderson --- libxfs/xfs_da_format.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/libxfs/xfs_da_format.h b/libxfs/xfs_da_format.h index 9bd2e6b..bb5d8ec 100644 --- a/libxfs/xfs_da_format.h +++ b/libxfs/xfs_da_format.h @@ -885,4 +885,29 @@ 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__ */