Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> writes:
> Neil Brown <neilb@xxxxxxx> writes:
>> Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> writes:
>>
>>> Hi Neil,
>>>
>>> I think we have some bad side effects with this patch:
>>>
>>> commit 199dc6ed5179251fa6158a461499c24bdd99c836
>>> Author: NeilBrown <neilb@xxxxxxxx>
>>> Date: Mon Aug 3 13:11:47 2015 +1000
>>>
>>> md/raid0: update queue parameter in a safer location.
>>>
>>> When a (e.g.) RAID5 array is reshaped to RAID0, the updating
>>> of queue parameters (e.g. max number of sectors per bio) is
>>> done in the wrong place.
>>> It should be part of ->run, but it is actually part of ->takeover.
>>> This means it happens before level_store() calls:
>>>
>>> blk_set_stacking_limits(&mddev->queue->limits);
>>>
>>> Running the '03r0assem' test suite fills my kernel log with output like
>>> below. Yi Zhang also had issues where writes failed too.
>>>
>>> robably something we need to resolve for 4.2-final or revert the
>>> offending patch.
>>>
>>> Cheers,
>>> Jes
>>>
>>> md: bind<loop0>
>>> md: bind<loop1>
>>> md: bind<loop2>
>>> md/raid0:md2: md_size is 116736 sectors.
>>> md: RAID0 configuration for md2 - 1 zone
>>> md: zone0=[loop0/loop1/loop2]
>>> zone-offset= 0KB, device-offset= 0KB, size= 58368KB
>>>
>>> md2: detected capacity change from 0 to 59768832
>>> bio too big device loop0 (296 > 255)
>>> bio too big device loop0 (272 > 255)
>>
>> 1/ Why do you blame that particular patch?
>>
>> 2/ Where is that error message coming from? I cannot find "bio too big"
>> in the kernel (except in a comment).
>> Commit: 54efd50bfd87 ("block: make generic_make_request handle
>> arbitrarily sized bios")
>> removed the only instance of the error message that I know of.
>>
>> Which kernel exactly are you testing?
>
> I blame it because of bisect - I revert that patch and the issue goes
> away.
>
> I checked out 199dc6ed5179251fa6158a461499c24bdd99c836 in Linus' tree,
> see the bio too large. I revert it and it goes away.
Hmmm Xiao tells me that the warning message is not in upstream, but I
was sure I reproduced it in the upstream kernel as well. If I screwed
up, my apologies, I am going back to my cave and will investigate
further.
Jes
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