[Ocfs2-devel] [PATCH] ocfs2: fix __ocfs2_cluster_lock() dead lock

[Sunil Mushran]

Yes, we expect it to fix the issue. I'll send the patches after I get  
to work.

On Jan 21, 2010, at 7:30 AM, David Teigland <teigland at redhat.com> wrote:

> On Wed, Jan 13, 2010 at 11:14:48AM -0800, Sunil Mushran wrote:
>> Joel Becker wrote:
>>> On Wed, Jan 13, 2010 at 11:20:49AM +0800, Wengang Wang wrote:
>>>> before update_holders, the lock could be DCed(since no BUSY flag  
>>>> set by
>>>> here).
>>>>
>>>> and even after update_holders, the lock could be DCed too.
>>>>
>>>> so that we get ocfs2_cluster_lock()(with holders increased)  
>>>> returned
>>>> sucessfully
>>>> but actually we don't hold the dlm lock. --thus more than one  
>>>> node is
>>>> considering that they have the (EX) lock.
>>>
>>>    You make a good point.  I don't like the solution you propose,
>>> though.  Another flag that's almost the same?  Eww!  There's got  
>>> to be a
>>> better way.
>>
>> I don't see how we can resolve this without another flag. It could
>> be a mirror image of the PENDING flag. PENDING takes care of the gap
>> between BUSY set and calling dlm_lock(). This flag has to take care
>> of the gap between BUSY clear and inc_holders.
>>
>> Am working on improving Wengang's patch.
>
> I'm afraid I lost track of which patches I should be trying.  Is there
> something that we expect should solve the known problems, even if  
> it's not
> a final version?
> Dave
>