FreeBSD NFS server not responding to TCP SYN packets from Linux/SunOS clients

[rick at snowhite.cis.uoguelph.ca]

[good stuff snipped]
> threads), but they wait until the disks are not busy.  I'm not really 
> sure what it would give you to have the nfsd's wait until disk is not as 
> busy, as that is what it is doing now, right?  Maybe you would smooth 

The difference is that, if the nfsd threads don't take the request off
the socket receive queue, then the TCP send window slows/stops new
requests being sent from the client at some point.

Currently, the nfsd thread takes the request off the TCP sockets receive
queue and then sleeps inside the VFS/VnodeOp calls.
(As noted in the previous email, I think what happens now is good enough
 for most cases, so long as the client doesn't retry the RPCs. I had
 forgotten that the TCP seq# would cause TCP level retransmits to be
 discarded, even after the request is removed from the receive queue.)

Fun stuff, rick