On Jul 7, 2008, at 2:20 PM, Trond Myklebust wrote:
On Thu, 2008-07-03 at 16:45 -0400, J. Bruce Fields wrote:
On Mon, Jun 30, 2008 at 06:38:35PM -0400, Chuck Lever wrote:
Hi Trond-
Seven patches that implement kernel RPC service registration via
rpcbind v4.
This allows the kernel to advertise IPv4-only services on hosts
with IPv6
addresses, for example.
This is Trond's baliwick, but I read through all 7 quickly and they
looked good to me....
They look more or less OK to me too, however I'm a bit unhappy about
the
RPC_TASK_ONESHOT name: it isn't at all descriptive.
Open to suggestions. I thought RPC_TASK_FAIL_WITHOUT_CONNECTION was a
bit wordy ;-)
I also have questions about the change to a TCP socket here. Why not
just implement connected UDP sockets?
Changing rpcb_register() to use a TCP socket is less work overall, and
we get a positive hand shake between the kernel and user space when
the TCP connection is opened.
Other services might also want to use TCP+ONESHOT for several short
requests over a real network with actual packet loss, but they might
find CUDP+ONESHOT less practical/reliable (or even forbidden in the
case of NFSv4). So we would end up with something of a one-off
implementation for rpcb_register.
The downside of using TCP in this case is that it's more overhead: 8
packets instead of two for registration in the common case, and it
leaves a single privileged port in TIME_WAIT for each registered
service. I don't think this matters much as registration happens
quite infrequently.
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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