linux-ext4 - Re: Corrupted superblock? But disk still mounts.

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Date:	Fri, 22 Aug 2014 11:09:53 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	Mark Ballard <markjballard@...glemail.com>
CC:	linux-ext4@...r.kernel.org
Subject: Re: Corrupted superblock? But disk still mounts.

On 8/22/14, 9:19 AM, Mark Ballard wrote:
> Ya. It did look that way. 'Scuse me for not checking first.
> 
> But my point is that it may still be a problem for ext4, dumpe2fs,
> e2fsck, fsck and presumably gparted and so on.
> 
> That is, would it not be polite of them to report the error ...<drum
> roll>... accurately?

Ah, I see.  So you don't like "corrupted" - you'd like to know that it's
something else perfectly valid, just not the thing you were looking for.

Maybe like:

# misc/dumpe2fs /dev/sdc1
dumpe2fs 1.43-WIP (09-Jul-2014)
misc/dumpe2fs: Superblock checksum does not match superblock while trying to open /dev/sdc1
Couldn't find valid filesystem superblock.
/dev/sdc1 contains a xfs file system

# misc/dumpe2fs /dev/sdc
dumpe2fs 1.43-WIP (09-Jul-2014)
misc/dumpe2fs: Superblock checksum does not match superblock while trying to open /dev/sdc
Couldn't find valid filesystem superblock.
/dev/sdc is entire device, not just one partition!

-Eric

> (No irony intended.)
> 
> 
> On 19 August 2014 15:36, Eric Sandeen <sandeen@...hat.com> wrote:
>> On 8/18/14, 3:23 PM, Mark Ballard wrote:
>>>> I'm guessing that it's the encryption getting in your way.
>>>
>>> Cheers, Eric. Does rather look that way. But for the sake of a user report...
>>>
>>>>
>>>> How is /dev/sdb1 encrypted?  Usually this is done with something like dm-crypt.
>>>> Or is it hardware encryption managed in the bios?  Did you unlock it?
>>>
>>> Done with crytpsetup using luks.
>>>
>>>>
>>>> What does "blkid /dev/sdb1" say?
>>>>
>>>
>>> It says Luks.
>>
>> and not ext4 - so you need to unlock it via mumblemumbleLuksStuffmumblemumble
>> before you can operate on it with e2fsprogs tools.
>>
>> # cryptsetup luksOpen /dev/sdb1 <name>... or something.  Sorry, I'm not a LUKS
>> expert...
>>
>> Anyway, not an ext4 problem.  Your superblock isn't corrupted, it's encrypted.  :)
>>
>> -Eric
>>

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