nfs-locks

I use nfs for years inside lans. Actually I frequently run into the same problem:

If the network-connection is lost for short period (i.e. : wlan goes down) than
the mounted nfs-shares get a pain in the ass. I cannot unmount them, cause the
umount-process just keeps hanging (even if I specify the -f switch) and every
other command that access the mounted share seems just keep hanging (I name lsof
and bash-filename-completion). They cant even be killed, but need a kill -9.


Is this just the lousy setup I have at my system or is this just a deeper flaw
in nfs

mainly I use following entry in fstab on client-side:
10.21.1.2:/data3 /matrix/data3 nfs rw,bg,wsize=8196,rsize=8196 0 0

and on server in exports:
/data3 *(rw,async,no_root_squash)

I use the nfs-kernel-server and 2.6.20-kernels right here on this machine and I
really need to reboot this machine now, cause I've got 4 dead nfs-connection and
cant bring them back to life. (I even tried stopping the nfs-kernel-server on
the server, but the clients remain stubborn)

Thnx for any insight, alternatives and tips. Actually I dont want to use smb,
cause nfs is so simply and smb has its own drawbacks.

thnx
peter