[OpenAFS-devel] Problem with CB_WhoAreYou

[Volker Lendecke]

--AqsLC8rIMeq19msA
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Tue, Feb 08, 2005 at 05:28:10PM -0500, Jeffrey Hutzelman wrote:
> If you are noticing actual problems, rather than just messages in your=20
> FileLog, please describe what they are.

Sorry, it was a bit late yesterday. I had found out that I had not described
any problem myself...

The problem is an apparently hanging file server. The 1.2.11 on Linux 2.4.21
clients sends FetchStatus requests on behalf of different uid's in high vol=
ume.
RX challenge/response proceeds, as do ptserver queries by the file server. =
The
file server also sends the WhoAreYou requests back to the client which are
normally replied to very quickly. The routine in afs_callback.c does not ha=
ve
to work particularly hard. But after some requests have been successfully
processed, some WhoAreYou call seems stuck in the client. The server is for=
ced
to re-send the query for in my case about 90 seconds or even longer, the cl=
ient
sends a RX-level ack, but no WhoAreYou replies. Meanwhile other FetchStatus
requests pile up, all obviously waiting in a queue to get their chance to i=
ssue
the WhoAreYou requests.

During this state, a lot of RX Ack stuff is going on, but nothing else. No =
CPU
on either the client or server side, no disk activity, and no network traff=
ic
that might remotely create a bottleneck.

When the server finally gives up, normal processing resumes. I created a
version of afs_callback.c without the ObtainReadLock by hard-coding the
information requested, but this did not help, the client seems stuck in ano=
ther
lock. Not asking for the WhoAreYou at all obviously helped, but this can at
best be called a hack.

Volker

--AqsLC8rIMeq19msA
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.5 (GNU/Linux)

iD8DBQFCCb1wP/hMgvhmbo4RAmjKAJ9yaLjrpbT/ODWDSMkIplG9wGlw3QCeNjBr
6KgcpPnwxgFox3wev453jfg=
=iSg8
-----END PGP SIGNATURE-----

--AqsLC8rIMeq19msA--