[OpenAFS] Misconfigured Windows client hangs Linux server

[Jeffrey Altman]

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Rainer Toebbicke wrote:
> Jeffrey Altman wrote:
> 
>> I don't see how that could hang the server running on linux.
>> A failure to support digital signatures will prevent the
>> Windows AFS Client service from being able to process the
>> requests and send a response that the Windows CIFS client
>> will respond to.
>>
> 
> Having a fileserver dump with a similar case on my desk I can confirm
> that a windows client can indeed "hang" an AFS server (although I don't
> know if that had anything to do with digital signatures).
> 
> The scenario: all threads blocked in h_Lock_r on the same host,
> triggered by a SRXAFS_GetTime call. Except the one holding the lock who
> is waiting for RXAFSCB_WhoAreYou (to that host). Sure, it will
> eventually time out if there is no response but if the GetTime RPCs are
> sufficiently frequent this will do the job.

What version of the Windows client?

Is the client reachable from the server?

WhoAreYou is not implemented in clients earlier than 1.3.8000.
If the client is 1.3.8000 or higher, what do rxdebug and cmdebug
report for the client?

> Shows that we still need some hardening effort in the fileserver,
> perhaps a quota of simultaneous calls/host or similar, with a VBUSY
> return whenever that quota is exceeded. We already do this automatically
> when a particular volume has more users than 1/2 the threads and there
> are calls waiting - happens frequently with a farm behind.

Do you have a proposed patch?

Jeffrey Altman

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