[dm-devel] kernel BUG at drivers/md/persistent-data/dm-btree-remove.c:182!

[Nikolay Borisov]

After reading the assembly again with a colleague
I can confirm that in my case the target is also set
to #MAX-1 and then I have full nodes so it's very
likely that I'm hitting the same problem that you
reported. I've also hit it twice now on the same
server in a 24 hour period. I will apply your patch
and see if this helps.

Mike, Joe

Could you take a look at Dennis' patches and
express some opinions on the issue?

On Tue, Oct 20, 2015 at 5:39 AM, Dennis Yang <shinrairis at gmail.com> wrote:
> Hi,
>
> After I analyzed the metadata of this case couple months ago, I find
> out that there is another possible bug which might trigger this
> assertion fail in shift(). I had posted a patch two months ago on the
> list to explain and fix this issue. Could you help reviewing this?
>
> https://www.redhat.com/archives/dm-devel/2015-August/msg00155.html
>
> Thanks,
> Dennis
>
> 2015-10-20 0:02 GMT+08:00 Mike Snitzer <snitzer at redhat.com>:
>> On Mon, Oct 19 2015 at  6:45am -0400,
>> Nikolay Borisov <n.borisov at siteground.com> wrote:
>>
>>>
>>>
>>> On 10/19/2015 01:30 PM, Joe Thornber wrote:
>>> > On Mon, Oct 19, 2015 at 12:16:53PM +0300, Nikolay Borisov wrote:
>>> >> [Resending as I had typo in the dm-devel's mailing list the first time]
>>> >>
>>> >> Hello,
>>> >>
>>> >> Using kernel 3.12.47 I've hit the aforementioned issue. I'd also like
>>> >> to say that this kernel does include Dennis Yang's patch which
>>> >> supposedly fixes a similar issue
>>> >> (https://www.redhat.com/archives/dm-devel/2015-May/msg00113.html).
>>> >
>>> >
>>> > Did you apply this patch or my corrected patch?
>>> >
>>> > https://www.redhat.com/archives/dm-devel/2015-May/msg00123.html
>>>
>>> I haven't applied anything per-se, rather this stable kernel does
>>> include your corrected patch. So yes, the correct fix for the issue
>>> reported by Dennis is included, yet apparently the same issue is
>>> manifesting again.
>>
>> Are you using metadata snapshots at all?
>> Do you have this commit applied?
>>
>> b0dc3c8bc15 ("dm btree: add ref counting ops for the leaves of top level btrees")
>>
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