Date: Mon, 14 Sep 2009 21:59:42 +0300 From: Andriy Gapon <avg@icyb.net.ua> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: freebsd-fs@freebsd.org, qing.li@bluecoat.com, freebsd-current@freebsd.org Subject: Re: NFS client defaults to a mix of UDP and TCP Message-ID: <4AAE929E.3040904@icyb.net.ua> In-Reply-To: <Pine.GSO.4.63.0909141222550.19469@muncher.cs.uoguelph.ca> References: <Pine.GSO.4.63.0909131356020.12138@muncher.cs.uoguelph.ca> <200909140858.34592.jhb@freebsd.org> <4AAE4513.6030701@icyb.net.ua> <Pine.GSO.4.63.0909141222550.19469@muncher.cs.uoguelph.ca>
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on 14/09/2009 19:27 Rick Macklem said the following:
>
>
> On Mon, 14 Sep 2009, Andriy Gapon wrote:
>
>> on 14/09/2009 15:58 John Baldwin said the following:
>>>
>>> Yes. I know of folks would love to have NFS use only TCP, including the
>>> initial RPC portmapper requests. IMO an NFS mount should use TCP for
>>> everything and a UDP mount should use UDP for everything by default.
>>>
>>
>> And another fact - it seems that NFS umount unconditionally uses UDP
>> for "something":
>>
>> /*
>> * Report to mountd-server which nfsname
>> * has been unmounted.
>> */
>> if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
>> clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS, "udp");
>> ...
>>
> Yep. This one is somewhat less critical IMO, since this RPC is just
> fyi for the mountd on the server and, if it fails for any reason, only
> normally affects the output of "showmount" and doesn't break the umount.
> (That doesn't mean I don't think it should be fixed, but it can be done
> separately from resolving what mount_nfs needs to default to.)
I agree. It's just that given the nature of UDP it takes a very long while for
umount to re-alize that nobody's listening in some situations.
--
Andriy Gapon
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