nfs got worse

[Thomas Klausner <tk%giga.or.at@localhost>]

Hi!

I've recently upgraded to 6.99.49 on machine that's NFS mounting from
a Synology NAS via amd.

In the last days, files on the NFS shares stopped being accessible
multiple times, hanging accesses to the whole share.

I've been able to trigger it like this at least twice:

run mplayer on a file on the server
pause
come back later, unpause

mplayer currently hangs in
 2933 wiz       85    0   191M   34M nfscn2/8   0:13  0.00%  0.00% mplayer

I also saw processes hung in "nfsrcv/5" when accessing the directory
on which mplayer was hanging.

Since I saw this the first time, I've made the nfs mounts 'tcp' mounts
(I was using the default before) and even got rid of amd and mounted
them directly with /etc/fstab. Neither of these helped.

I currently assume that it's not the server's fault because the server
is right now still accessible via HTTPS, and rebooting NetBSD usually
made the problem disappear -- after a reboot I can access the files
again.

I'm not sure where to look for more details.

I haven't seen this before at all, so I suspect some recent changes
(after Jun 20) in the NFS or network code. Does anyone have ideas?

 Thomas