[Ocfs2-devel] dlm stress test hangs OCFS2

[Sunil Mushran]

Please could you log a bugzilla (oss.oracle.com/bugzilla) and attach
the logs to it.

Sunil Mushran wrote:
> The patch does not have a fix. Only tracing. We may have to disable
> a printk for the 2 node to reproduce.
>
> For the BUG, can I have the full logs. The oops trace and the tracing
> from all nodes.
>
> Thanks
> Sunil
>
> Coly Li wrote:
>   
>> Hi Sunil,
>>
>> I tried this patch, on 2 nodes cluster, it works. No blocking observed so far.
>> Then I run it on a 4 nodes cluster, run make_panic on each node simultaneously,
>> and BUG inside ocfs2_prepare_downconvert() triggered (in line 3224) on one of
>> the nodes (I observed the oops on node x4),
>>
>> 3214 static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
>> 3215                                               int new_level)
>> 3216 {
>> 3217         assert_spin_locked(&lockres->l_lock);
>> 3218
>> 3219         BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
>> 3220
>> 3221         if (lockres->l_level <= new_level) {
>> 3222                 mlog(ML_ERROR, "lockres->l_level (%d) <= new_level (%d)\n",
>> 3223                      lockres->l_level, new_level);
>> 3224                 BUG();
>> 3225         }
>> 3226
>> 3227         mlog(ML_NOTICE, "lock %s, new_level = %d, l_blocking = %d\n",
>> 3228              lockres->l_name, new_level, lockres->l_blocking);
>> 3229
>> 3230         lockres->l_action = OCFS2_AST_DOWNCONVERT;
>> 3231         lockres->l_requested = new_level;
>> 3232         lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
>> 3233         return lockres_set_pending(lockres);
>> 3234 }
>>
>> I am trying to understand what you did now :-)
>>
>> Sunil Mushran Wrote:
>>   
>>     
>>> So originally my thinking was that the dc thread was not getting kicked.
>>> That is not the case. The lock is getting downconverted. But it is getting
>>> upconverted shortly thereafter. This just could be the case in which
>>> dlmglue
>>> is slow to increment the holders to block the dc thread from downconverting
>>> the lock. The snippet shows that BAST is received 16 usecs after the
>>> upconvert.
>>>
>>> Coly, I have another patch. Pop out the older patch before applying this
>>> one.
>>> http://oss.oracle.com/~smushran/0001-ocfs2-Patch-to-debug-hang-in-dlmglue-when-running-d.patch
>>>
>>>     
>>>       
>
>
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