From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Zwisler Subject: mkfs.ext4 -D option fails to mount Date: Thu, 29 Jun 2017 09:35:38 -0600 Message-ID: <20170629153538.GA4268@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: linux-ext4@vger.kernel.org Return-path: Received: from mga04.intel.com ([192.55.52.120]:59112 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753299AbdF2Pfk (ORCPT ); Thu, 29 Jun 2017 11:35:40 -0400 Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-ID: Our validation team noticed that in some configurations mkfs.ext4 with the -D option creates a filesystem that can't be mounted: # mkfs.ext4 -D -F /dev/pmem5 mke2fs 1.43.3 (04-Sep-2016) /dev/pmem5 contains a ext4 file system last mounted on Tue Jul 26 07:44:19 2016 Creating filesystem with 65027584 4k blocks and 16261120 inodes Filesystem UUID: 6f95ece9-d4cb-4cfc-bc22-211119d5efe7 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872 Allocating group tables: done Writing inode tables: done Creating journal (262144 blocks): done Writing superblocks and filesystem accounting information: done # mount /dev/pmem5 /mnt mount: wrong fs type, bad option, bad superblock on /dev/pmem5, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. where dmesg says: EXT4-fs (pmem5): ext4_check_descriptors: Block bitmap for group 1 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode bitmap for group 1 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode table for group 1 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Block bitmap for group 2 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode bitmap for group 2 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode table for group 2 overlaps superblock ... EXT4-fs (pmem5): ext4_check_descriptors: Block bitmap for group 63 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode bitmap for group 63 overlaps superblock EXT4-fs (pmem5): ext4_check_descriptors: Inode table for group 63 overlaps superblock EXT4-fs (pmem5): no journal found If we omit the "-D" option from mkfs.ext4, everything works. Note also that this behavior is independent of the DAX mount option. This isn't blocking us, I just thought you would want to know. - Ross