From: Mark Ballard Subject: Corrupted superblock? But disk still mounts. Date: Mon, 18 Aug 2014 19:14:19 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE To: linux-ext4@vger.kernel.org Return-path: Received: from mail-vc0-f172.google.com ([209.85.220.172]:42476 "EHLO mail-vc0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751696AbaHRSOU convert rfc822-to-8bit (ORCPT ); Mon, 18 Aug 2014 14:14:20 -0400 Received: by mail-vc0-f172.google.com with SMTP id im17so6260462vcb.3 for ; Mon, 18 Aug 2014 11:14:19 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: =46ound bad superblock when trying to rename partition using e2label. The same problem has prevented me using dumpe2fs, e2fsck and fsck to try and resolve the problem. But I can still mount the disk and use it. The disk is encrypted. It is not the boot disk. The OS - Xubuntu - has gone helicopter a few times, spiraling out with disk crunching that locks up the machine for so long that I have been faced with no choice but to switch it off at the wall. That is not likely to do with this hick disk being discussed here, but it does mean the hick disk has been knocked out a few times. --------------------------------------------- Here's what happens when I attempt to rename: # e2label /dev/sdb1 e2label: Bad magic number in super-block while trying to open /dev/sdb1 Couldn't find valid filesystem superblock. Two other partitions on the same disk accepted the rename command. fdisk -l gives output consistent with normal conditions. The disk is not using LVM. --------------------------------------------- Here's what happens when I try and run the disk utilities: # dumpe2fs /dev/sdb1 | grep =E2=80=93i superblock grep: superblock: No such file or directory dumpe2fs 1.42.9 (4-Feb-2014) dumpe2fs: Bad magic number in super-block while trying to open /dev/sdb= 1 # e2fsck /dev/sdb1 e2fsck 1.42.9 (4-Feb-2014) ext2fs_open2: Bad magic number in super-block e2fsck: Superblock invalid, trying backup blocks... e2fsck: Bad magic number in super-block while trying to open /dev/sdb1 The superblock could not be read or does not describe a valid ext2/ext3= /ext4 filesystem. If the device is valid and it really contains an ext2/ext3= /ext4 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblo= ck: e2fsck -b 8193 or e2fsck -b 32768 # blockdev --getbsz /dev/sdb1 4096 # e2fsck -b 32768 /dev/sdb1 e2fsck 1.42.9 (4-Feb-2014) e2fsck: Bad magic number in super-block while trying to open /dev/sdb1 The superblock could not be read or does not describe a valid ext2/ext3= /ext4 filesystem. If the device is valid and it really contains an ext2/ext3= /ext4 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblo= ck: e2fsck -b 8193 or e2fsck -b 32768 # fsck.ext4 -v /dev/sdb1 e2fsck 1.42.9 (4-Feb-2014) ext2fs_open2: Bad magic number in super-block fsck.ext4: Superblock invalid, trying backup blocks... fsck.ext4: Bad magic number in super-block while trying to open /dev/sd= b1 The superblock could not be read or does not describe a valid ext2/ext3= /ext4 filesystem. If the device is valid and it really contains an ext2/ext3= /ext4 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblo= ck: e2fsck -b 8193 or e2fsck -b 32768 ------------------------------ mke2fs -n listed 14 backup superblocks, running each of through e2fsck produced the same error bar one: e2fsck 1.42.9 (4-Feb-2014) e2fsck: Bad magic number in super-block while trying to open /dev/sdb1 The superblock could not be read or does not describe a valid ext2/ext3= /ext4 filesystem. If the device is valid and it really contains an ext2/ext3= /ext4 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblo= ck: e2fsck -b 8193 or e2fsck -b 32768 One of the backups gave this with e2fsck: e2fsck 1.42.9 (4-Feb-2014) e2fsck: Attempt to read block from filesystem resulted in short read while trying to open /dev/sdb1 Could this be a zero-length partition? ---------------------------- Mark Ballard =46reelance journalist twitter.com/markjballard Best tel: +44(0)1474 566 118 Mob tel: +44(0)79 827 00815 markjballard@googlemail.com -----------------------------------------------------------------------= ---- -----------------------------------------------------------------------= ---- Public Sector IT Blog: http://www.computerweekly.com/blogs/public-sector/ -----------------------------------------------------------------------= ---- RSS updates: http://www.computerweekly.com/blogs/public-sector/atom.xml -----------------------------------------------------------------------= ----- -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html