From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 695E7C2BC61 for ; Sun, 28 Oct 2018 21:44:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 185022082D for ; Sun, 28 Oct 2018 21:44:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 185022082D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=nod.at Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728044AbeJ2GaL convert rfc822-to-8bit (ORCPT ); Mon, 29 Oct 2018 02:30:11 -0400 Received: from lilium.sigma-star.at ([109.75.188.150]:43440 "EHLO lilium.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728009AbeJ2GaL (ORCPT ); Mon, 29 Oct 2018 02:30:11 -0400 Received: from localhost (localhost [127.0.0.1]) by lilium.sigma-star.at (Postfix) with ESMTP id 2364318011ADE; Sun, 28 Oct 2018 22:44:15 +0100 (CET) From: Richard Weinberger To: linux-mtd@lists.infradead.org Cc: linux-kernel@vger.kernel.org, russell@personaltelco.net, zajec5@gmail.com, Richard Weinberger , stable@vger.kernel.org Subject: [PATCH] ubifs: Handle re-linking of inodes correctly while recovery Date: Sun, 28 Oct 2018 22:44:07 +0100 Message-Id: <20181028214407.20965-1-richard@nod.at> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org UBIFS's recovery code strictly assumes that a deleted inode will never come back, therefore it removes all data which belongs to that inode as soon it faces an inode with link count 0 in the replay list. Before O_TMPFILE this assumption was perfectly fine. With O_TMPFILE it can lead to data loss upon a power-cut. Consider a journal with entries like: 0: inode X (nlink = 0) /* O_TMPFILE was created */ 1: data for inode X /* Someone writes to the temp file */ 2: inode X (nlink = 0) /* inode was changed, xattr, chmod, … */ 3: inode X (nlink = 1) /* inode was re-linked via linkat() */ Upon replay of entry #2 UBIFS will drop all data that belongs to inode X, this will lead to an empty file after mounting. As solution for this problem, scan the replay list for a re-link entry before dropping data. Fixes: 474b93704f32 ("ubifs: Implement O_TMPFILE") Cc: stable@vger.kernel.org Reported-by: Russell Senior Reported-by: Rafał Miłecki Signed-off-by: Richard Weinberger --- Russel, Rafał, please give this patch another testing. I'll also run it on different test systems before merging. Thanks, //richard --- fs/ubifs/replay.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c index 4844538eb926..65a780685b82 100644 --- a/fs/ubifs/replay.c +++ b/fs/ubifs/replay.c @@ -209,6 +209,34 @@ static int trun_remove_range(struct ubifs_info *c, struct replay_entry *r) return ubifs_tnc_remove_range(c, &min_key, &max_key); } +/** + * inode_relinked - check whether inode in question will be re-linked. + * @c: UBIFS file-system description object + * @rino: replay entry to test + * + * O_TMPFILE files can be re-linked, this means link count goes from 0 to 1. + * This case needs special care, otherwise all references to the inode will + * be removed upon the first replay entry of an inode with link count 0 + * is found. + */ +static bool inode_relinked(struct ubifs_info *c, struct replay_entry *rino) +{ + struct replay_entry *r = rino; + + ubifs_assert(c, rino->deletion); + ubifs_assert(c, key_type(c, &rino->key) == UBIFS_INO_KEY); + + list_for_each_entry_from(r, &c->replay_list, list) { + if (key_inum(c, &r->key) == key_inum(c, &rino->key) && + r->deletion == 0) { + ubifs_assert(c, r->sqnum > rino->sqnum); + return true; + } + } + + return false; +} + /** * apply_replay_entry - apply a replay entry to the TNC. * @c: UBIFS file-system description object @@ -236,6 +264,11 @@ static int apply_replay_entry(struct ubifs_info *c, struct replay_entry *r) { ino_t inum = key_inum(c, &r->key); + if (inode_relinked(c, r)) { + err = 0; + break; + } + err = ubifs_tnc_remove_ino(c, inum); break; } -- 2.19.1