XFS corruption on ubuntu 2.6.27-9-server

[Eric Sandeen]

George Barnett wrote:
> On 04/02/2009, at 12:28 PM, Eric Sandeen wrote:
> 
>> George Barnett wrote:
>>> Hi,
>>>
>>> I'm seeing the following errors:
>>>
>>> [822153.422851] Filesystem "md2": XFS internal error xfs_da_do_buf(2)
>>> at line 2107 of file /build/buildd/linux-2.6.27/fs/xfs/
>> we really should make that more informative.
>>
>> What it means is that you read a piece of metadata that did not match
>> any of the metadata magic numbers.
>>
>> hard to say whether it might be an xfs bug I think; this does come up
>> occasionally though and it'd at least be nice to print more details on
>> the error (what the magic *was*, what block, etc)
>>
>> Do you happen to have the repair output?
>>
>> Did your md raid lose power w/ write cache enabled?
> 
> Hi Eric,
> 
> Thanks for your response.  The system did not lose power.  This  
> failure just "happens".  I have a cronjob which rsync's /data to a  
> spare drive that's not on raid.  It seems that is enough to cause this  
> failure.
> 
> Fortunately, I still have the xfs_repair output in my term buffer:
> 
> root at slut:/# xfs_repair /dev/md2
> Phase 1 - find and verify superblock...
> Phase 2 - using internal log
>          - zero log...
>          - scan filesystem freespace and inode maps...
>          - found root inode chunk
> Phase 3 - for each AG...
>          - scan and clear agi unlinked lists...
>          - process known inodes and perform inode discovery...
>          - agno = 0
> bad magic number 0x0 on inode 18042
> bad version number 0x0 on inode 18042
> bad magic number 0x0 on inode 18043
> bad version number 0x0 on inode 18043
> bad magic number 0x0 on inode 18044
> bad version number 0x0 on inode 18044
> bad magic number 0x0 on inode 18045
> bad version number 0x0 on inode 18045
> bad magic number 0x0 on inode 18046
> bad version number 0x0 on inode 18046
> bad magic number 0x0 on inode 18047
> bad version number 0x0 on inode 18047
> bad directory block magic # 0 in block 0 for directory inode 18000

Interesting that all the bad magic numbers were 0... not sure what to
make of that, offhand, I'm afraid...

-Eric