On Mon, Dec 22, 2008 at 5:36 PM, Manish Katiyar <mkatiyar@xxxxxxxxx> wrote:
On Mon, Dec 22, 2008 at 4:23 PM, pradeep singh
<pradeep.rautela@xxxxxxxxx> wrote:
> Hello,You may want to check the code of get_backup_sb() from file
> On Mon, Dec 22, 2008 at 4:10 PM, Sandeep K Sinha
> <sandeepksinha@xxxxxxxxx> wrote:
> [snip]
>>> Can you please describe any scenario, where this may happen?
>>> One i can think of is when your /sbin is groked.
>>>
>> Well, there can be many scenario's which may lead to such situations.
>> In commodity file systems liek ext2/ext3 we dont handle sector failures.
>> If such in-consistency occurs at your fs level, then you will be in
>> big problems.
>
> yes indeed.
>>
>> Also, there can be possible situations where your superblock gets
>> corrupted and the fsck wont have any information pertaining to the
>> disk layout of the Fs.
>> In such scenario, you won't even have access to the duplicate SB's.
>> Duplicate SB's are helpful mostly when you have some kind of
>> inconsistencies in the SB data but when the SB itself is corrupted,
>> who will tell you where the alternative SB is ?
>
> AFAIK , location of duplicate superblocks is decided by the block size
> and thus is not explicitly stored in the superblock, though I am not
> sure of this. Maybe one well versed with fs internals can shed some
> light on this matter.
e2fsprogs/e2fsck/util.c to see how it gets the backup superblock
number depending on the blocksize.
Thanks -
Manish
>
> Cu,
> --Pradeep
>
>>> I wonder if this is the case, then what happens when fsck itself
>>> cannot be invoked. though your superblock is intact you still cannot
>>> have a sane state for your fs because effectively fsck is not there.
>>> How do we handle such situations?
>>
>> Obviously you will have to have something like a fsck.
>> Look for some other similar tools.
>> Also, if fsck fails for its own reason, it will probably be temporary, I assume.
>>> Any hints?
>>>
>>
>>
>>> Thanks for the inputs Sandeep,
>>> ~Pradeep
>>>>
>>>> HTH,
>>>>
>>>>> Thanks,
>>>>> ~Pradeep
>>>>>>
>>>>>>>
>>>>>>> Thanks
>>>>>>> Shyam.
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Regards,
>>>>>> Sandeep.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> "To learn is to change. Education is a process that changes the learner."
>>>>>>
>>>>>> --
>>>>>> To unsubscribe from this list: send an email with
>>>>>> "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx
>>>>>> Please read the FAQ at http://kernelnewbies.org/FAQ
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Pradeep
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Regards,
>>>> Sandeep.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> "To learn is to change. Education is a process that changes the learner."
>>>>
>>>
>>>
>>>
>>> --
>>> Pradeep
>>>
>>
>>
>>
>> --
>> Regards,
>> Sandeep.
>>
>>
>>
>>
>>
>>
>> "To learn is to change. Education is a process that changes the learner."
>>
>
>
>
> --
> Pradeep
>
> --
> To unsubscribe from this list: send an email with
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> Please read the FAQ at http://kernelnewbies.org/FAQ
>
>
