nfs-bug when server for 9-Stable becomes client as well ?

[Arno J. Klaassen]

Hello,

looks like I discouvered a probable bug in the nfs-code, very
easy to reproduce in my setup :


   Machine-1 : Today's 9-stable, exporting /files (ufs) and /z2 (zfs)

   Machine-2 : 8-stable as of April the 10th exporting /raid1

On Machine-1 I mount /raid1 (rw,nfsv3,intr,tcp,rsize=32768,wsize=32768)
and start a script on this mount looping something like :

  dd if=/dev/random of=BIG bs=1048576 count=${SIZE}
  cp -fp BIG BIG2
  cmp -x BIG BIG2

I let this run for 24 hours (from time to time stressing Machine-1 with
other scripts, including provoking heavy swapping), no problem at all.

However, then I mount /z2 (rw,nfsv3,intr,tcp,rsize=32768,wsize=32768)
on Machine-2, and *immediately* the above loop on Machine-1 fails :

  Copying file ...cp: BIG: Permission denied

No console messages this time, last time I got 

  kernel: nfs_getpages: error 13
  kernel: vm_fault: pager read error, pid 87803 (cmp)

on Machine-1.

I repeated this scenario by replacing Machine-2 with a good old
6-4-stable one, same outcome.

Please tell me what I could do to nail this down a bit more.

Thanx in advance,

Best, Arno