[gentoo-user] Unable to mount root dir, Segmentation failure with mount

[gentoo-user] Unable to mount root dir, Segmentation failure with mount

[pge07beb]

Hi gentoo-users,

I'm running Gentoo flawlessly on my laptop for nearly one year now, but 
since yesterday, I'm in big trouble. At some instance (surfing in the 
web,.. nothing horrible) the screen froze and the only thing I was able to 
do, was pressing the power button 4seconds to shut the computer down.

I was never able to boot my system since then.

It sayed always things like: Not able to find root file system  (or 
likewise)

So I plugged in my live-cd to recover the whole thing...

But I wasn't able to mount the root partition, so I tried e2fsck, which 
turned out to find a whole lot of errors and told me that it corrected 
them.

Thus I retried to mount the file system, which resulted in an big error of 
mount, saying something about Kernel BUG (?!?)

At that point I realized that this could become a major problem for me, 
since all my personal data is on my root partition (I know, I should't do 
that...but thats the way things are right now)

I used dd to make a copy of this partition to an external hard disk, and 
begun to recover it from there.
dd gave no errors as it copied the partition, so I think this is no 
hardware failure

I rerun e2fsck on the partition, it corrected a little more, but after 
that, it didn't found anything new, but I still wasn't able to mount the 
partition (nor the partition dump)

The crutial part of the dmesg output seems to be:

Assertion failure in cleanup_journal_tail() at fs/jbd/checkpoint.c:430: 
"blocknr != 0"

Is this a known issue with ext3 filesystems?

Thaks in andvance for any help,

Carsten

PS: Please tell me if you need more information
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Re: [gentoo-user] Unable to mount root dir, Segmentation failure with mount

[Duane Griffin]

2008/7/14  <pge07beb@studserv.uni-leipzig.de>:
> Hi gentoo-users,
>
> I'm running Gentoo flawlessly on my laptop for nearly one year now, but
> since yesterday, I'm in big trouble. At some instance (surfing in the web,..
> nothing horrible) the screen froze and the only thing I was able to do, was
> pressing the power button 4seconds to shut the computer down.
>
> I was never able to boot my system since then.
>
> It sayed always things like: Not able to find root file system  (or
> likewise)

Ouch.

> So I plugged in my live-cd to recover the whole thing...

Good idea.

> But I wasn't able to mount the root partition, so I tried e2fsck, which
> turned out to find a whole lot of errors and told me that it corrected them.

Not such a good idea. For future reference, unless you don't mind
losing the data, always take a block-level snapshot, if possible,
before doing anything else. You don't know what state things are in,
writing to it could make the situation worse.

> Thus I retried to mount the file system, which resulted in an big error of
> mount, saying something about Kernel BUG (?!?)

D'oh! Congratulations, you found a kernel bug! :)

> At that point I realized that this could become a major problem for me,
> since all my personal data is on my root partition (I know, I should't do
> that...but thats the way things are right now)

Oh dear. You have backups, right?

> I used dd to make a copy of this partition to an external hard disk, and
> begun to recover it from there.

Excellent!

> dd gave no errors as it copied the partition, so I think this is no hardware
> failure

Hopefully. I'd be extra careful about backups for a while, though.

> I rerun e2fsck on the partition, it corrected a little more, but after that,
> it didn't found anything new, but I still wasn't able to mount the partition
> (nor the partition dump)
>
> The crutial part of the dmesg output seems to be:
>
> Assertion failure in cleanup_journal_tail() at fs/jbd/checkpoint.c:430:
> "blocknr != 0"
>
> Is this a known issue with ext3 filesystems?

Google says someone else hit it once upon a time, but it doesn't seem
to be listed on the kernel bugzilla. Your journal is corrupted and the
kernel is not being as careful as it should before using on-disk data.
If you remove the journal you will hopefully get some or all of your
data back. On a *COPY* of the partition image do the following to
replace the old journal with a new one:

tune2fs -O ^has_journal <image>
e2fsck -f <image>
tune2fs -j <image>
e2fsck -f <image>

If everything looks OK and the data you care about is all there then
you can go ahead and fix up your real disk. If you wouldn't mind
though, please keep a copy of the corrupted image. I'll prepare a
patch to fix the BUG and it would be helpful if you could test it once
it is ready.

> Thaks in andvance for any help,
>
> Carsten

Cheers,
Duane.

-- 
"I never could learn to drink that blood and call it wine" - Bob Dylan
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Re: [gentoo-user] Unable to mount root dir, Segmentation failure with mount

[Volker Armin Hemmann]

Hi,

in your case: go to lkml with your problems. There the people who wrote the 
stuff. They are probably the only ones who can really help you.

And yes, the great ones will need more information. Like kernel version, exact 
error message, version of the tools used, hardware ... 




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[gentoo-user] Re: Unable to mount root dir, Segmentation failure with mount

[Nikos Chantziaras]

pge07beb@studserv.uni-leipzig.de wrote:
> 
> Hi gentoo-users,
> 
> I'm running Gentoo flawlessly on my laptop for nearly one year now, but 
> since yesterday, I'm in big trouble. At some instance (surfing in the 
> web,.. nothing horrible) the screen froze and the only thing I was able 
> to do, was pressing the power button 4seconds to shut the computer down.
> 
> I was never able to boot my system since then.
> 
> It sayed always things like: Not able to find root file system  (or 
> likewise)

There was good advice from the other users here, but also try a live CD 
with a more recent kernel (Gentoo 2008.0-r1 for example, or something 
else like openSUSE 11).  Also, if removing the journal doesn't work, try 
to mount it as ext2 (ext3 is backwards compatible with ext2 so doing 
that is perfectly OK).

As to the cause of this, I suspect a hardware failure due to overheating 
(laptops tend to do that if you don't open them and give them a thorough 
cleaning each 10 months or so).  I'm an overclocker and things like this 
can happen when a CPU or chipset overheats (corrupted data starts to get 
written on disk).  The other possibility is that the drive is dying 
(damaged sectors).

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Re: [gentoo-user] Unable to mount root dir, Segmentation failure with mount

[pge07beb]

thaks, this one helped me:

I followed those steps, and where able to recover my system.

On Tue, Jul 15, 2008 at 02:34:42AM +0100, Duane Griffin wrote:
> Google says someone else hit it once upon a time, but it doesn't seem
> to be listed on the kernel bugzilla. Your journal is corrupted and the
> kernel is not being as careful as it should before using on-disk data.
> If you remove the journal you will hopefully get some or all of your
> data back. On a *COPY* of the partition image do the following to
> replace the old journal with a new one:
> 
> tune2fs -O ^has_journal <image>
> e2fsck -f <image>
> tune2fs -j <image>
> e2fsck -f <image>
> 
> If everything looks OK and the data you care about is all there then
> you can go ahead and fix up your real disk. If you wouldn't mind
> though, please keep a copy of the corrupted image. I'll prepare a
> patch to fix the BUG and it would be helpful if you could test it once
> it is ready.
> 
> > Thaks in andvance for any help,
> >
> > Carsten
> 
> Cheers,
> Duane.

I'd like to help, so that this problem can be fixed, if you got anything
ready, just send it to me, and I'll giv it a try on that corrupted image.

bye,
Carsten

I now get other problems, but will tell you about later... 
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Re: [gentoo-user] Unable to mount root dir, Segmentation failure with mount

[Duane Griffin]

2008/7/17  <pge07beb@studserv.uni-leipzig.de>:
> I followed those steps, and where able to recover my system.

Excellent, I'm pleased to hear that!

> I'd like to help, so that this problem can be fixed, if you got anything
> ready, just send it to me, and I'll giv it a try on that corrupted image.

Thanks, I'll send a couple of patches to you shortly, offline.

Cheers,
Duane.

-- 
"I never could learn to drink that blood and call it wine" - Bob Dylan
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