[gentoo-user] configuring NFS server to handle client reboots

[Timur Aydin <ta@taydin.org>]

Hi,

I am using Gentoo Linux as an NFS server while doing development on an
Blackfin embedded system. The Blackfin is running uClinux and the
development host is Gentoo testing version (~amd64). The NFS server
version is 1.2.7.

Here is the problem that I am observing: I start from a known state,
restarting the NFS server on Gentoo and power cycling the Blackfin. Once
the Blackfin system has booted, I mount an folder on the Blackfin. This
succeeds without any problem. Then I power cycle the Blackfin again and
after it is up, I try to mount that same folder again. But this time,
the mount command hangs for a minute or so and eventually fails with a
timeout error.

Here is the mount command:

mount -o nolock,tcp 10.2.2.254:/romfs_2011R1 /mnt

When I look into the NFS server's system log, I can see that the mount
was authenticated:

Jun 30 13:54:53 bonsai rpc.mountd[1597]: authenticated mount request
from 10.2.2.220:911 for /home/ta/uclinux_2011R1/db1/uclinux-dist/romfs
(/home/ta/uclinux_2011R1)

I have captured what is happening using wireshark and what I am seeing
is that the mount request succeeds, but the client initiates another TCP
connection (SYN) and this SYN is never responded to by the server.

I know that a sm-notify program is used on both NFS clients/servers to
notify reboots, but this embedded system does not have the sm-notify
capability. And I would rather not try to port it to uClinux.

So, my question is, can I somehow configure the NFS server to allow
mounting the same directory repeatedly whenever the NFS client reboots?

-- 
Timur