Subject: Re: [ NFS: How to make FreeBSD fall on
To: Frank van der Linden , void <>
From: Conrad Minshall <>
List: tech-kern
Date: 12/15/2001 15:35:57
At 4:12 AM -0800 12/14/01, Frank van der Linden wrote:
>On Thu, Dec 13, 2001 at 07:15:07PM +0000, void wrote:
>> The attached code has exposed several bugs in FreeBSD's NFS client
>> code, and at least one general filesystem bug, related to soft updates.
>> The full details are in the freebsd-hackers archive.
>This little program did not show any NFS client problems on
>NetBSD-current. It did show FFS(+softdep) problems on both
>-current and the 1.5 branch. It produced incorrect output
>on a few runs on the 1.5 branch, NFS client side, but they
>looked to be a VM problem rather than an NFS problem.
>So, no NFS-specific trouble, but definitely showing some
>serious problems.

Once it runs aok for a few million operations, try concurrently running:

#! /bin/sh
while :
  sleep 1

In OS X I used that to flush :) out a couple more bugs.  (In OS X a sync is
done every 30 seconds by "update".  Increasing the frequency 30x exposed
races involving nfs_flush() and our unified buffer cache.)

Conrad Minshall,, 408 974-2749
Apple Computer, Mac OS X Core Operating Systems