From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57302 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726948AbeI0PvX (ORCPT ); Thu, 27 Sep 2018 11:51:23 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Torsten Hilbrich , Theodore Tso Subject: [PATCH 4.4 22/28] ext4: fix online resizes handling of a too-small final block group Date: Thu, 27 Sep 2018 11:06:46 +0200 Message-Id: <20180927090638.606585824@linuxfoundation.org> In-Reply-To: <20180927090637.687829444@linuxfoundation.org> References: <20180927090637.687829444@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit f0a459dec5495a3580f8d784555e6f8f3bf7f263 upstream. Avoid growing the file system to an extent so that the last block group is too small to hold all of the metadata that must be stored in the block group. This problem can be triggered with the following reproducer: umount /mnt mke2fs -F -m0 -b 4096 -t ext4 -O resize_inode,^has_journal \ -E resize=1073741824 /tmp/foo.img 128M mount /tmp/foo.img /mnt truncate --size 1708M /tmp/foo.img resize2fs /dev/loop0 295400 umount /mnt e2fsck -fy /tmp/foo.img Reported-by: Torsten Hilbrich Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/resize.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1954,6 +1954,26 @@ retry: } } + /* + * Make sure the last group has enough space so that it's + * guaranteed to have enough space for all metadata blocks + * that it might need to hold. (We might not need to store + * the inode table blocks in the last block group, but there + * will be cases where this might be needed.) + */ + if ((ext4_group_first_block_no(sb, n_group) + + ext4_group_overhead_blocks(sb, n_group) + 2 + + sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) { + n_blocks_count = ext4_group_first_block_no(sb, n_group); + n_group--; + n_blocks_count_retry = 0; + if (resize_inode) { + iput(resize_inode); + resize_inode = NULL; + } + goto retry; + } + /* extend the last group */ if (n_group == o_group) add = n_blocks_count - o_blocks_count;