freebsd stable - Apr 2005 - 4.x smbfs getdirentries() failure - need help debugging

Hi all,

Have been doing my best to plod through debugging an issue with SMBFS on
FreeBSD 4.11, where with a certain size directory, getdirentries()
returns errno=9 (Bad file descriptor) when it reaches the end of the
directory listing. I've traced it that far and found PR 78953 that
appears to be the same issue, but am a bit out of my depth as to where
to go from here.

http://www.freebsd.org/cgi/query-pr.cgi?pr=78953

Would anyone be able to provide any pointers on where to go from here in
trying to track down the cause? I've provided instructions that reliably
allow me to reproduce the problem with a Windows XP machine as the
source for the smbfs share, if anyone wants to have a look...

At this point I'm guessing I need DDB to figure out what the kernel's
doing and determine exactly where & why this error is arrising.

Any help would be much appreciated, as at this point I'm into the
unchartered (for me) world of the kernel! :-)

Regards
Antony