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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 05443C48BDE for ; Sun, 7 Jul 2019 19:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D11F820838 for ; Sun, 7 Jul 2019 19:38:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727834AbfGGTiu (ORCPT ); Sun, 7 Jul 2019 15:38:50 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57286 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727549AbfGGTiI (ORCPT ); Sun, 7 Jul 2019 15:38:08 -0400 Received: from 94.197.121.43.threembb.co.uk ([94.197.121.43] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hkCz5-0006hG-UV; Sun, 07 Jul 2019 20:38:04 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hkCz4-0005bK-GN; Sun, 07 Jul 2019 20:38:02 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Theodore Ts'o" , "Jan Kara" Date: Sun, 07 Jul 2019 17:54:17 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 063/129] ext4: fix crash during online resizing In-Reply-To: X-SA-Exim-Connect-IP: 94.197.121.43 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.70-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit f96c3ac8dfc24b4e38fc4c2eba5fea2107b929d1 upstream. When computing maximum size of filesystem possible with given number of group descriptor blocks, we forget to include s_first_data_block into the number of blocks. Thus for filesystems with non-zero s_first_data_block it can happen that computed maximum filesystem size is actually lower than current filesystem size which confuses the code and eventually leads to a BUG_ON in ext4_alloc_group_tables() hitting on flex_gd->count == 0. The problem can be reproduced like: truncate -s 100g /tmp/image mkfs.ext4 -b 1024 -E resize=262144 /tmp/image 32768 mount -t ext4 -o loop /tmp/image /mnt resize2fs /dev/loop0 262145 resize2fs /dev/loop0 300000 Fix the problem by properly including s_first_data_block into the computed number of filesystem blocks. Fixes: 1c6bd7173d66 "ext4: convert file system to meta_bg if needed..." Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings --- fs/ext4/resize.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1931,7 +1931,8 @@ retry: le16_to_cpu(es->s_reserved_gdt_blocks); n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb); n_blocks_count = (ext4_fsblk_t)n_group * - EXT4_BLOCKS_PER_GROUP(sb); + EXT4_BLOCKS_PER_GROUP(sb) + + le32_to_cpu(es->s_first_data_block); n_group--; /* set to last group number */ }