Re: Regression- XFS won't mount on partitioned md array

[David Greaves <david@dgreaves.com>]

Eric Sandeen wrote:
> Eric Sandeen wrote:
>> Eric Sandeen wrote:
>>
>>> I'll see if I have a little time today to track down the problem.
>>
>> Does this patch fix it for you?  Does for me though I can't yet explain
>> why ;)
>>
>> http://www.linux.sgi.com/archives/xfs/2008-05/msg00190.html
>>
>> -Eric
Yes, this fixes it for me - thanks :)

> So what's happening is that xfs is trying to read a page-sized IO from
> the last sector of the log... which goes off the end of the device.
> This looks like another regression introduced by
> a9759f2de38a3443d5107bddde03b4f3f550060e, but fixed by Christoph's patch
> in the URL above, which should be headed towards -stable.
Damn, I guess I misread my bisect readings when things crashed then.
Still, I said 'around' :)

> (aside: it seems that this breaks any external log setup where the log
> consists of the entire device... but I'd have expected the xfsqa suite
> to catch this...?)
> 
> The patch avoids the problem by looking for some extra locking but it
> seems to me that the root cause is that the buffer being read at this
> point doesn't have it's b_offset, the offset in it's page, set.  Might
> be another little buglet but harmless it seems.
mmmm
'little buglets' in the filesystem holding a few Tb of data...
mmmm
Anything I can do to help find that? I suspect not if you can reproduce it.

Anyhow - thanks again.

David
PS I'll be back soon, back in 2.6.23 I was hitting a hibernate/xfs bug which
I've been avoiding by powering down. Well, it's still there in 2.6.25.3...