posix locking on OCFS2

[Rowland Penny]

On 23/11/14 11:35, Min Wai Chan wrote:
> Dear Rowland,
>
> I did test with ping_ping before
> The ping_pong testing do work...
>
> -- according to this
> https://wiki.samba.org/index.php/Ping_pong
>
>
> Thank You
>
> On Sun, Nov 23, 2014 at 7:15 PM, Ralph Böhme <rb at sernet.de> wrote:
>
>> On Sat, Nov 22, 2014 at 11:03:26PM +0100, David Disseldorp wrote:
>>> On Fri, 21 Nov 2014 11:47:54 +0100, Ralph Böhme wrote:
>>>
>>>>> Unfortunately, POSIX file locks, also known as lockf(3) or fcntl(2)
>> locks
>>>>> are not yet supported in a cluster manner. We hope to have that
>> ready in an
>>>>> upcoming version of Ocfs2.
>>>> possibly a documentation bug? Few lines below it states:
>>> Yes, the documentation is just out of date. OCFS2 (alongside DLM)
>>> supports cluster coherent POSIX locks, which can be tested via the
>>> ping_pong tool provided with ctdb.  I've reverted the erroneous Wiki
>>> update.
>> thanks David!
>>
>> -Ralph
>>
>> --
>> SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
>> phone: +49-551-370000-0, fax: +49-551-370000-9
>> AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
>> http://www.sernet.de,mailto:kontakt@sernet.de
>>
OK, getting confused now

Amitay posted this link:

https://oss.oracle.com/osswiki/OCFS2/NewFeaturesList.html

Which has this:

Cluster aware flock(2)

     Required Kernel: Linux 2.6.26

     Required Tools: Any

The flock(2) system call is now cluster aware. File locks taken on one 
node from userspace will interact with those taken on other nodes. All 
flock(2) options are supported, including the kernels ability to cancel 
a lock request when an appropriate kill signal is recieved by the user. 
Unfortunately, POSIX file locks, also known as lockf(3) or fcntl(2) 
locks are not yet supported in a cluster manner. We hope to have that 
ready in an upcoming version of Ocfs2.

It also has this:

Cluster aware POSIX file locks (fcntl(), lockf())

     Required Kernel: Linux 2.6.28

     Required Tools: Any - userspace cluster stack required

POSIX locks are now cluster aware. Locks taken on one node will interact 
with those taken on another node. Due to the group communication 
required to make these locks coherent, a userspace cluster is required.

What is the difference between fcntl() & fcntl(2), also lockf() & 
lockf(3) ???? Which is required ???

According to Steve, CTDB does not work, if this is so and I have no 
reason to believe he is lying (I mean, why would he, what would he 
gain???), the problem needs to be identified and documented until it is 
fixed.

Rowland