rebuild fs

rebuild fs

[Thorsten Mauch]

Hi all
I have a raid5 system where two hard disks were turned out. One of the
failed drive was
Still accessible. I made a copy with:
 dd  if=/dev/sba  of=/dev/sdb conv=noerror,sync

With the copied drive I could access the array again. Unfortunately I
couldn't mount
My reiserfs anymore. I try to rebuild the fs structure with:
reiserfsck  --rebuild-db
reiserfsck  --rebuild-tree

But while rebuilding the tree, I got a segmentation fault. Because I didn't
want to continue work on the original raid system, I copied the entire raid
disk to the IDE disk.

dd  if=/dev/rd/c0d0  of=/dev/hda conv=noerror,sync

I tried to rebuild the fs structure again, and  I was able to access many
files, but not that are important to me :(
Does there is anyting I can do in this state ? does other tools then
resierfsck exist ?

Re: rebuild fs

[Oleg Drokin]

Hello!

On Tue, Aug 05, 2003 at 12:02:02PM +0200, Thorsten Mauch wrote:

> But while rebuilding the tree, I got a segmentation fault. Because I didn't
> want to continue work on the original raid system, I copied the entire raid
> disk to the IDE disk.
> dd  if=/dev/rd/c0d0  of=/dev/hda conv=noerror,sync
> I tried to rebuild the fs structure again, and  I was able to access many
> files, but not that are important to me :(
> Does there is anyting I can do in this state ? does other tools then
> resierfsck exist ?

If you are not using latest fsck version (3.6.11 as of now), try to use reiserfsprogs 3.6.11,
as there is slight chance it would do better.

Bye,
    Oleg

Re: rebuild fs

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Tue, Aug 05, 2003 at 12:02:02PM +0200, Thorsten Mauch wrote:
>
>  
>
>>But while rebuilding the tree, I got a segmentation fault. Because I didn't
>>want to continue work on the original raid system, I copied the entire raid
>>disk to the IDE disk.
>>dd  if=/dev/rd/c0d0  of=/dev/hda conv=noerror,sync
>>I tried to rebuild the fs structure again, and  I was able to access many
>>files, but not that are important to me :(
>>Does there is anyting I can do in this state ? does other tools then
>>resierfsck exist ?
>>    
>>
>
>If you are not using latest fsck version (3.6.11 as of now), try to use reiserfsprogs 3.6.11,
>as there is slight chance it would do better.
>
>Bye,
>    Oleg
>
>
>  
>
rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
will at least be fixed regardless of whether fsck has enough data to do 
its job.

-- 
Hans

Re: rebuild fs

[Oleg Drokin]

Hello!

On Tue, Aug 05, 2003 at 04:28:15PM +0400, Hans Reiser wrote:
> >>But while rebuilding the tree, I got a segmentation fault. Because I 
> >>didn't
> >>want to continue work on the original raid system, I copied the entire 
> >>raid
> >>disk to the IDE disk.
> >>dd  if=/dev/rd/c0d0  of=/dev/hda conv=noerror,sync
> >>I tried to rebuild the fs structure again, and  I was able to access many
> >>files, but not that are important to me :(
> >>Does there is anyting I can do in this state ? does other tools then
> >>resierfsck exist ?
> >If you are not using latest fsck version (3.6.11 as of now), try to use 
> >reiserfsprogs 3.6.11,
> >as there is slight chance it would do better.
> rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
> will at least be fixed regardless of whether fsck has enough data to do 
> its job.

But it was not failing on the IDE drive anyway.

Bye,
    Oleg

Re: rebuild fs

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Tue, Aug 05, 2003 at 04:28:15PM +0400, Hans Reiser wrote:
>  
>
>>>>But while rebuilding the tree, I got a segmentation fault. Because I 
>>>>didn't
>>>>want to continue work on the original raid system, I copied the entire 
>>>>raid
>>>>disk to the IDE disk.
>>>>dd  if=/dev/rd/c0d0  of=/dev/hda conv=noerror,sync
>>>>I tried to rebuild the fs structure again, and  I was able to access many
>>>>files, but not that are important to me :(
>>>>Does there is anyting I can do in this state ? does other tools then
>>>>resierfsck exist ?
>>>>        
>>>>
>>>If you are not using latest fsck version (3.6.11 as of now), try to use 
>>>reiserfsprogs 3.6.11,
>>>as there is slight chance it would do better.
>>>      
>>>
>>rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
>>will at least be fixed regardless of whether fsck has enough data to do 
>>its job.
>>    
>>
>
>But it was not failing on the IDE drive anyway.
>
>Bye,
>    Oleg
>
>
>  
>
I don't understand the relevance of your statement to mine.

-- 
Hans

Re: rebuild fs

[Thorsten Mauch]

well, the segmentation fault was with version 2.6.3 from knoppix CD. After I
kopied
the drive to IDE i used a debian unstable dist to run reiserfsck. I think i
rember the 
version was 2.6.8. Here it run without foult but i didn't run it again
against the raid system.

Menawhile I compiled the version 2.6.11 but is still running so currently I
have no result

Re: rebuild fs

[Oleg Drokin]

Hello!

On Tue, Aug 05, 2003 at 04:56:55PM +0400, Hans Reiser wrote:

> >>rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
> >>will at least be fixed regardless of whether fsck has enough data to do 
> >>its job.
> >But it was not failing on the IDE drive anyway.
> I don't understand the relevance of your statement to mine.

Since after transferring image to IDE made reiserfsck to not fail (and it failed on raid5 due to raid errors,
I think), your "if it still fails" statement was not adequate.
Current problem is that not everything is restored and some important files were lost.
Now, I know that recently we introduced some serious changes in reiserfsck and now
if the block have some slight corruption, it is not immediately discarded, but fsck actually
tries to extract some useful data out of it if it think this is really reiserfs metadata block.
That's why newer reiserfsck might achieve better results.

Bye,
    Oleg

Re: rebuild fs

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Tue, Aug 05, 2003 at 04:56:55PM +0400, Hans Reiser wrote:
>
>  
>
>>>>rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
>>>>will at least be fixed regardless of whether fsck has enough data to do 
>>>>its job.
>>>>        
>>>>
>>>But it was not failing on the IDE drive anyway.
>>>      
>>>
>>I don't understand the relevance of your statement to mine.
>>    
>>
>
>Since after transferring image to IDE made reiserfsck to not fail (and it failed on raid5 due to raid errors,
>I think), your "if it still fails" statement was not adequate., 
>
Even with a broken hard drive, there should be no userspace segfault.... 
or am I wrong?

>Current problem is that not everything is restored and some important files were lost.
>Now, I know that recently we introduced some serious changes in reiserfsck and now
>if the block have some slight corruption, it is not immediately discarded, but fsck actually
>tries to extract some useful data out of it if it think this is really reiserfs metadata block.
>That's why newer reiserfsck might achieve better results.
>
>Bye,
>    Oleg
>
>
>  
>


-- 
Hans

Re: rebuild fs

[Oleg Drokin]

Hello!

On Tue, Aug 05, 2003 at 05:28:25PM +0400, Hans Reiser wrote:
> >>>>rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
> >>>>will at least be fixed regardless of whether fsck has enough data to do 
> >>>>its job.
> >>>But it was not failing on the IDE drive anyway.
> >>I don't understand the relevance of your statement to mine.
> >Since after transferring image to IDE made reiserfsck to not fail (and it 
> >failed on raid5 due to raid errors,
> >I think), your "if it still fails" statement was not adequate., 
> Even with a broken hard drive, there should be no userspace segfault.... 
> or am I wrong?

in this case (IO error) reiserfsck does abort() which ends up as signal number 5, and core is dumped if this is allowed.
Looks pretty much like segfault too.
Though a message is printed prior to this that we cannot read some block.

Bye,
    Oleg

Re: rebuild fs

[Hans Reiser]

Oleg Drokin wrote:

>Hello!
>
>On Tue, Aug 05, 2003 at 05:28:25PM +0400, Hans Reiser wrote:
>  
>
>>>>>>rephrase that as, use 3.6.11, if it still fails, tell us, the segfault 
>>>>>>will at least be fixed regardless of whether fsck has enough data to do 
>>>>>>its job.
>>>>>>            
>>>>>>
>>>>>But it was not failing on the IDE drive anyway.
>>>>>          
>>>>>
>>>>I don't understand the relevance of your statement to mine.
>>>>        
>>>>
>>>Since after transferring image to IDE made reiserfsck to not fail (and it 
>>>failed on raid5 due to raid errors,
>>>I think), your "if it still fails" statement was not adequate., 
>>>      
>>>
>>Even with a broken hard drive, there should be no userspace segfault.... 
>>or am I wrong?
>>    
>>
>
>in this case (IO error) reiserfsck does abort() which ends up as signal number 5, and core is dumped if this is allowed.
>Looks pretty much like segfault too.
>Though a message is printed prior to this that we cannot read some block.
>
>Bye,
>    Oleg
>
>
>  
>
yuck.  vs, complain to vitaly please.

-- 
Hans

Re: rebuild fs

[Vitaly Fertman]

> >in this case (IO error) reiserfsck does abort() which ends up as signal
> > number 5, and core is dumped if this is allowed. Looks pretty much like
> > segfault too.
> >Though a message is printed prior to this that we cannot read some block.
> >
> >Bye,
> >    Oleg
>
> yuck.  vs, complain to vitaly please.

It does not look the same as the user gets different messages on the terminal.
With hardware problems like IO errors he gets "Aborting", although this can dump
the core file also. But what a user should not get even with the broken hardware 
is "Segmentation fault" messages. And core dumping is what looks really pretty 
much the same. 

As some old version of reiserfsck (3.6.3) stopped unexpectedly, Oleg suggested 
to use the latest one -- 3.6.11 -- which worked ok for now.

Regarding IO errors reiserfsck prints "Block ## cannot be read" before aborting 
and the last ones suggest to check the hardware also.

BTW, if there are some bad blocks I would advise to use dd_rescue instead of dd
as dd has some problems with bad blocks handling.

-- 
Thanks,
Vitaly Fertman

Re: rebuild fs

[Hans Reiser]

Vitaly Fertman wrote:

>>>in this case (IO error) reiserfsck does abort() which ends up as signal
>>>number 5, and core is dumped if this is allowed. Looks pretty much like
>>>segfault too.
>>>Though a message is printed prior to this that we cannot read some block.
>>>
>>>Bye,
>>>   Oleg
>>>      
>>>
>>yuck.  vs, complain to vitaly please.
>>    
>>
>
>It does not look the same as the user gets different messages on the terminal.
>With hardware problems like IO errors he gets "Aborting", although this can dump
>the core file also. But what a user should not get even with the broken hardware 
>is "Segmentation fault" messages. And core dumping is what looks really pretty 
>much the same. 
>
>As some old version of reiserfsck (3.6.3) stopped unexpectedly, Oleg suggested 
>to use the latest one -- 3.6.11 -- which worked ok for now.
>
>Regarding IO errors reiserfsck prints "Block ## cannot be read" before aborting 
>and the last ones suggest to check the hardware also.
>
>BTW, if there are some bad blocks I would advise to use dd_rescue instead of dd
>as dd has some problems with bad blocks handling.
>
>  
>
ok, you fixed the unfriendliness in latest version, excellent.

-- 
Hans