[OpenAFS] who has that file open

[Jeffrey Altman]

This is a cryptographically signed message in MIME format.

--------------ms080300070803000702030801
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

David Bear wrote:
> since file locking is 'just around the corner' for openafs (at least
> I'm hopeful) the question I have now is will (is) there be a way to
> ask the server who has a particular file open. the afs server has to
> keep track of which client has a file open in order to force the cache
> manager to do its callback functions correct? If so, there should be a
> way to query the afs server to see who has fileX open.
> 
> This would be a really nice feature...

At the present time there is no such functionality.   The way that
the server maintains each file's lock status with a timestamp and a 
simple counter that can be in one of three states:

    0:  no locks held

   >0:  one or more read locks are held

   -1:  a write lock is held

In order to ensure that a lock is not issued to a client that goes away
and never returns, a lock is issued with a five minute expiration time.
As long as some client within five minutes extends the lock, the lock
status will be maintained.

This implementation is light weight and fast but does not provide the
information necessary to implement a "WhoIsLocking" RPC.  It is 
important to remember that the File Server does not know who has a
file open.  The File Server can possibly be aware of two things:

  * which clients are holding a valid callback for a given unit of
    data (volume, directory, file, ...) depending on the scope of the
    callbacks.

  * which clients are holding locks (assuming that the file server
    was re-written to keep track of such things.)

Holding a callback does not imply anything about the status of a file
being open.  It simply means that there is a valid copy of the data
being held in a client's cache.

Even if the file server did contain a list of valid locks, would an
RPC indicating IP addresses of lock holding clients be enough for you
or are you looking for a list of the authenticated user names on whose
behalf the locks were obtained?

Jeffrey Altman

--------------ms080300070803000702030801
Content-Type: application/x-pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
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--------------ms080300070803000702030801--