Re: Reiserfs Data Recovery

Re: Reiserfs Data Recovery

[Nick Vahalik]

'lo All,

I've been doing some reading through some of the "hidden features" in 
the source code...

Are these features tested?  Is there any more documentation on them 
besides just what's in the comments?  Are there any good sites to read 
up some more on reiserfs v3.6 internals?  I've become determined to get 
this data back.  I've got a couple ideas that I'd like to try but look 
at some of these commands I see that some of the things I'd like to 
access may already be written.

If the problem is that there are sections of my tree missing, why can't 
we just chop the bad sections off and salvage the data that is still 
there?  Are there any tools that do this?

Nick Vahalik

Re: Reiserfs Data Recovery

[Vladimir Saveliev]

Hello

On Wed, 2004-03-10 at 06:07, Nick Vahalik wrote:
> 'lo All,
> 
> I've been doing some reading through some of the "hidden features" in 
> the source code...
> 
> Are these features tested?  

Most of these things were added quickly to solve certain user problems.
To use them one is to understand what they were created for.

> Is there any more documentation on them 
> besides just what's in the comments?

no.

>   Are there any good sites to read 
> up some more on reiserfs v3.6 internals? 

namesys.com had description of reiserfs internals. But now it does not.
read source code instead

>  I've become determined to get 
> this data back.  I've got a couple ideas that I'd like to try but look 
> at some of these commands I see that some of the things I'd like to 
> access may already be written.
> 
> If the problem is that there are sections of my tree missing, why can't 
> we just chop the bad sections off and salvage the data that is still 
> there?  Are there any tools that do this?
> 

did you try reiserfsck?

> Nick Vahalik
> 

Re: Reiserfs Data Recovery

[Nick Vahalik]

Vladimir Saveliev wrote:

>>Are these features tested?  
>>    
>>
>
>Most of these things were added quickly to solve certain user problems.
>To use them one is to understand what they were created for.
>
>  
>
And I guess that isn't documented....

>>Is there any more documentation on them 
>>besides just what's in the comments?
>>    
>>
>
>no.
>  
>

>>  Are there any good sites to read 
>>up some more on reiserfs v3.6 internals? 
>>    
>>
>
>namesys.com had description of reiserfs internals. But now it does not.
>read source code instead
>  
>
Is there a reason?  I grabbed a copy of the whitepaper from archive.org 
and started reading it last night.  Is that information out of date... 
or is it taken down pending the release of Reiserv4?

>> I've become determined to get 
>>this data back.  I've got a couple ideas that I'd like to try but look 
>>at some of these commands I see that some of the things I'd like to 
>>access may already be written.
>>
>>If the problem is that there are sections of my tree missing, why can't 
>>we just chop the bad sections off and salvage the data that is still 
>>there?  Are there any tools that do this?
>>    
>>
>did you try reiserfsck?
>  
>
Yes... with --rebuild-tree, and it aborts after Pass0 every time.  It 
fixes... maybe 10 leaves... and then it finds a bad pointer (or 
something) and dies every time it runs.

Nick Vahalik

Re: Reiserfs Data Recovery

[Vladimir Saveliev]

Hello

On Wed, 2004-03-10 at 18:08, Nick Vahalik wrote:
> Vladimir Saveliev wrote:
> 
> >>Are these features tested?  
> >>    
> >>
> >
> >Most of these things were added quickly to solve certain user problems.
> >To use them one is to understand what they were created for.
> >
> >  
> >
> And I guess that isn't documented....
> 
> >>Is there any more documentation on them 
> >>besides just what's in the comments?
> >>    
> >>
> >
> >no.
> >  
> >
> 
> >>  Are there any good sites to read 
> >>up some more on reiserfs v3.6 internals? 
> >>    
> >>
> >
> >namesys.com had description of reiserfs internals. But now it does not.
> >read source code instead
> >  
> >
> Is there a reason?  I grabbed a copy of the whitepaper from archive.org 
> and started reading it last night.  Is that information out of date... 
> or is it taken down pending the release of Reiserv4?
> 
I have no idea why it was removed. I will try to find out.

> >> I've become determined to get 
> >>this data back.  I've got a couple ideas that I'd like to try but look 
> >>at some of these commands I see that some of the things I'd like to 
> >>access may already be written.
> >>
> >>If the problem is that there are sections of my tree missing, why can't 
> >>we just chop the bad sections off and salvage the data that is still 
> >>there?  Are there any tools that do this?
> >>    
> >>
> >did you try reiserfsck?
> >  
> >
> Yes... with --rebuild-tree, and it aborts after Pass0 every time.  It 
> fixes... maybe 10 leaves... and then it finds a bad pointer (or 
> something) and dies every time it runs.
> 

Are you using reiserfsck from
ftp://ftp.namesys.com/pub/reiserfsprogs/reiserfsprogs-3.6.13.tar.gz?

If yes - please run
debugreiserfs -p /dev/problemdevice | bzip2 -c > problemdevice.bz2
and make problemdevice.bz2 available for downloading.

It should allow us to fix reiserfsck bug.

If you are using older rieserfsck (reiserfsck -V), please try with the
one of
ftp://ftp.namesys.com/pub/reiserfsprogs/reiserfsprogs-3.6.13.tar.gz

> Nick Vahalik
> 

Re: Reiserfs Data Recovery

[Nick Vahalik]

Vladimir Saveliev wrote:

>Are you using reiserfsck from
>ftp://ftp.namesys.com/pub/reiserfsprogs/reiserfsprogs-3.6.13.tar.gz?
>
>If yes - please run
>debugreiserfs -p /dev/problemdevice | bzip2 -c > problemdevice.bz2
>and make problemdevice.bz2 available for downloading.
>
>It should allow us to fix reiserfsck bug.
>
>If you are using older rieserfsck (reiserfsck -V), please try with the
>one of
>ftp://ftp.namesys.com/pub/reiserfsprogs/reiserfsprogs-3.6.13.tar.gz
>  
>
root@bardiel:~/reiserdata# debugreiserfs -V
debugreiserfs 3.6.13 (2003 www.namesys.com)

root@bardiel:~/reiserdata# debugreiserfs -p /dev/sda1 | bzip2 -c > 
devsda1.bz2
debugreiserfs 3.6.13 (2003 www.namesys.com)
 
Loading on-disk bitmap .. 38677079 bits set - done
super block..ok
bitmaps..(1228).. ok
journal (from 18 to 8210)..ok
Super block, bitmaps, journal - 9422 blocks - done, 38667657 blocks left
0%....20%....40%....60%....80%....100%                       left 0, 
15211 /sec
Packed 66463 blocks:
        compessed 63534
        full blocks 2929
                leaves with broken block head 55
                corrupted leaves 83
                internals 672
                descriptors 0
data packed with ratio 0.09

The meta-data info can be downloaded at 
http://24.162.126.168:8080/devsda1.bz2
~5.3 MB

Thanks

Nick Vahalik

Re: Reiserfs Data Recovery

[Nick Vahalik]

Vitaly Fertman wrote:

>Hello,
>
>  
>
>>The meta-data info can be downloaded at
>>http://24.162.126.168:8080/devsda1.bz2
>>~5.3 MB
>>    
>>
>
>I have tried fsck on these metadata and had no problems.
>Did you compile progs on the same conputer where you 
>run it?
>
>  
>
Yes, I did.

Re: Reiserfs Data Recovery

[Stewart Smith]

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On Wed, 2004-03-10 at 22:41, Vladimir Saveliev wrote:
> namesys.com had description of reiserfs internals. But now it does not.
> read source code instead

Is it possible to get all of these documents back and in a nice, central
location? Historical documents can be quite interesting, especially in
trying to understand the design process of modern file systems.


-- 
Stewart Smith (stewart@flamingspork.com)
http://www.flamingspork.com/


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Re: Reiserfs Data Recovery (SOLVED)

[Nick Vahalik]

Alright, so apparently it was the hardware... I'm not quite sure how, 
exactly, but something appears to be up.  I borrowed a 200 G drive and 
just dd'ed /dev/sda to /dev/sdb, and then reiserfscked /dev/sdb1... it 
took a lot longer, but when It finished it got through pass 4 completely 
and  had finished.  It had 6430 leaves it couldn't place, so they were 
put in lost+found, and most (85%) of the files are completely intact, 
but some of the bigger ones (divx/iso) were pretty tore up.  I also have 
a couple of files that nautilus thinks are 1.5 exabytes, yes exabytes. 

It still amazes me that even after both the drives completely passed the 
DFT, they are still acting strange.  Heh, silly Hitachi drives.

Thanks for your time, guys.

Nick Vahalik

Re: Reiserfs Data Recovery (SOLVED)

[Vitaly Fertman]

On Monday 15 March 2004 18:48, Nick Vahalik wrote:
> Alright, so apparently it was the hardware... I'm not quite sure how,
> exactly, but something appears to be up.  I borrowed a 200 G drive and
> just dd'ed /dev/sda to /dev/sdb, and then reiserfscked /dev/sdb1... it
> took a lot longer, but when It finished it got through pass 4 completely
> and  had finished.  It had 6430 leaves it couldn't place, so they were
> put in lost+found, and most (85%) of the files are completely intact,
> but some of the bigger ones (divx/iso) were pretty tore up.  I also have
> a couple of files that nautilus thinks are 1.5 exabytes, yes exabytes.

It is legal to have a file with the size greater then the real file 
body size. But if you do not want it, there is an option in reiserfsck 
--adjust-size that allows you to adjust the file size fo the real file 
body size.

> It still amazes me that even after both the drives completely passed the
> DFT, they are still acting strange.  Heh, silly Hitachi drives.
>
> Thanks for your time, guys.
>
> Nick Vahalik

-- 
Thanks,
Vitaly Fertman