[OpenAFS] hangs on modifications to top-level directory (1.6.x)

Simon Wilkinson sxw@your-file-system.com
Wed, 28 Nov 2012 17:19:59 +0000

> Any ideas, or suggestions for how else to find out what might be going
> on, would be much appreciated. I haven't found anything suggestive by
> searching.

This sounds a like you are waiting for a callback break to complete, or =
to time out. You should be able to verify this by looking at a tcpdump =
of traffic from the fileserver, or possibly by looking at the fileserver =
logs. Either of these will also allow you to identify the client which =
is in possession of the callback.

This often happens when a volume is being accessed simultaneously by a =
well connected machine, and one behind a badly configured NAT or =
firewall. If the machine behind the NAT is regularly accessing the =
volume (to check configuration files, dot file state or similar), then =
it will keep reacquiring the callback. However, when the callback is =
broken by the fileserver, the NAT prevents the client from seeing, and =
responding to the callback break. The fileserver will then wait until =
the callback timeout before returning success to the operation that =
caused the callback break.