Re: [PATCH] Add the .MASTER node to the eth-multiplexer.

[Da Zheng]

Sergiu Ivanov wrote:
> Hello,
> 
> On Wed, Dec 23, 2009 at 08:52:33AM +0800, Da Zheng wrote:
>> netfs_attempt_lookup locks this node and the node is unlocked by
>> libnetfs, right? I forget a lot:-) So why can the second lookup not
>> wait until the first one finishes?
> 
> I've tried to remove the mutex unlocking code and it seems to work.
> So, you are right :-)
You mean there isn't deadlock at all?
> 
>>> It has just occurred to me that it might also be acceptable to not
>>> lock the .MASTER node at all: after all, it is little more than a flag
>>> telling the multiplexer to act differently.  What do you think?
>>>
>> .MASTER is almost completely static. I guess it should be OK if we don't 
>> lock it.
> 
> I wonder whether not locking .MASTER is still relevant.  On the one
> hand, it would stress its conceptual authenticity; on the other hand,
> it would require additional code to achieve the same functionality.
If the code can work without unlocking .MASTER as you said above, that means 
libnetfs unlocks it, then we should lock .MASTER before netfs_attempt_lookup 
returns.

Zheng Da