Re: Help tracking down files on a bad block: understanding the output of debugreiserfs

[Dewey Sasser <dewey@sasser.com>]

Konstantin Münning wrote:
> Hi!
>
> Unfortunately I can't help you with the debugreiserfs output but maybe
> with another approach for finding the correct blocknum of the bad
> sector(s). Why don't you try
>
> badblocks -b 4096 /dev/hda5
>   
Interesting.  When reading the badblocks man page I originally 
interpreted something it said to mean that it wouldn't run against a 
mounted partition.  I see now that that is not the case.  It will only 
refuse to run doing tests which write the partition, which is as it 
should be.

The partition affected is the root partition of a machine 700 miles from 
my chair and there is no one near the box that had any kind of Linux 
knowledge.  I am therefore trying to do this as much "on-line" as 
possible.  I will run "badblocks" at some point but I'll still need a 
way of mapping the bad block or sector to the affected files.  (Yes, I 
do have backups :)
> dd of=/dev/null if=/dev/hda5 bs=4k count=1 skip=xxx
>
> with xxx the block number(s) of your calculation or output from
> badblocks. Just to check if the block you've found is really unreadable.
>   
That is indeed one of my additional questions -- does the fact that 
debugreiserfs prints data mean the block (sector, really) is readable?  
Or does it mean my math is incorrect.  "badblocks" should help me answer 
that question.
> How to identify the inode number corresponding to that block I can't
> tell but finding the file etc. to the inode may be done with
>
> find /mount-point-of-fs -inum xxx
>   
Yep.  That part I can handle.  It's that middle link I'm missing :)

Thanks for your response,

--
Dewey