[Pvfs2-users] Data corruption?

[Sam Lang]

On Jul 13, 2006, at 9:50 AM, Rob Ross wrote:

> The problem with storing things like parent directory handle in a  
> given directory/metafile is that you have to change them all in the  
> event of a rename. Gets nasty.

What about a level of indirection, where the dir handle is added as a  
keyval to the dirdata handle, and each of the entries in the  
directory store the dirdata handle, which doesn't change on a rename.

-sam

>
> Rob
>
> Murali Vilayannur wrote:
>> Hi Simon,
>>> The kernel where these errors are reported is  
>>> 2.6.16-1.2115_FC4smp and
>>> the files were restored using
>>> rsync -avv -B 4194304 /media/pvfs_backup/pvfs2-fs/   /pvfs2-fs/
>>>
>>> The "-B" forces a reasonable (4MB) block size, and it's
>>> rsync-2.6.8-1.FC4.1 which just uses read/write VFS calls.
>> Hmm.. I will also try and see if we can reproduce this error on our
>> setup..
>>> Is there any way of find which file/directory corresponds to a  
>>> given handle?
>> For a given handle, we can find out if it is a file or a directory.
>> But to know what is the name of the file/directory may not be  
>> possible
>> right now without traversing the entire tree and checking for the  
>> given
>> handle.
>> We could possibly store the parent handle as part of the keyval  
>> for the
>> given handle and work our way backwards. Sam and I had discussed the
>> possibility of doing that for some other thing. Just not sure if  
>> that was
>> worth the effort or if it was useful for any other feature.
>> But it sure seems like having that would be a good diagnostic aid  
>> in case
>> something bad happens..
>> Thanks,
>> Murali
>>>
>>> Sam Lang wrote:
>>>
>>>> Hi Simon,
>>>>
>>>> I'm not able to reproduce this yet on my machine.  Can you give  
>>>> me more
>>>> details about your setup?  What kernel version are you running  
>>>> on?  When
>>>> you did the restore from XFS, did you just copy everything over  
>>>> using cp?
>>>>
>>>> -sam
>>>>
>>>> Number Cruncher wrote:
>>>>
>>>>
>>>>> Sam Lang wrote:
>>>>>
>>>>>
>>>>>
>>>>>>> [E 13:38:09.445405] TROVE:DBPF:Berkeley DB: DB->get:  
>>>>>>> DB_NOTFOUND: No
>>>>>>> matching key/data pair found
>>>>>>> [E 13:38:09.448542] TROVE:DBPF:Berkeley DB: DB->get:  
>>>>>>> DB_NOTFOUND: No
>>>>>>> matching key/data pair found
>>>>>>> [E 13:38:09.470425] TROVE:DBPF:Berkeley DB: DB->get:  
>>>>>>> DB_NOTFOUND: No
>>>>>>> matching key/data pair found
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> This message was being printed for a non-failure case.  Its  
>>>>>> been removed
>>>>>> for that case in the 1.5.1 release.  It doesn't mean that  
>>>>>> anything is
>>>>>> wrong with your filesystem.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> The client kernel also sometimes reports:
>>>>>>>
>>>>>>> pvfs2_file_read: error writing to handle 1840698453, --  
>>>>>>> returning -2
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> I'm not sure about this one.  Is it always the same handle?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> Yes, I think so.
>>>>>
>>>>>
>>>>>
>>>>>>> And pvfs2-fsck gives:
>>>>>>> ....
>>>>>>> # looking for dirdata match to 920349294.
>>>>>>> # mgmt_get_dirdata returned 920349293.
>>>>>>> # looking for dirdata match to 613565917.
>>>>>>> # mgmt_get_dirdata returned 613565916.
>>>>>>> # looking for dirdata match to 1227132674.
>>>>>>> # mgmt_get_dirdata returned 1227132673.
>>>>>>> # second pass: finding orphaned sub trees.
>>>>>>> * not removing None 2454203121.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> The lines beginning with # are ok, this one is a little odd.   
>>>>>> Could you
>>>>>> send the whole output from fsck?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> It's a bit long (50k lines), so I've attached it as .txt.bz2
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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