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Date: Wed, 26 Nov 1997 00:43:00 -0800 (PST)
From: ji@research.att.com
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Subject: bin/5155: nullfs on top of nfs seems to be hanging machine running 2.2.2-RELEASE
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>Number:         5155
>Category:       bin
>Synopsis:       nullfs on top of nfs seems to be hanging machine running 2.2.2-RELEASE
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Nov 26 00:50:00 PST 1997
>Last-Modified:
>Originator:     John Ioannidis
>Organization:
AT&T Labs - Research
>Release:        2.2.2-RELEASE
>Environment:
FreeBSD elf.tla.org 2.2.2-RELEASE FreeBSD 2.2.2-RELEASE #1: Wed Nov  5 23:06:50 EST 1997     ji@elf.tla.org:/usr/src/sys/compile/ELF  i386

>Description:
Doing a null-fs mount of an NFS-mounted directory hangs machine when there is 
a lot of filesystem I/O involving the nullfs mount
>How-To-Repeat:
mount -t nfs server:/local/0 /n/server/local/0
mount -t null /n/server/local/0/home/ji /home/ji
 (where  /home lives in the root filesystem, of course).
when I start netscape (whith /home/ji as my home directory), the
machine freezes up after a few seconds. It won't even responds to pings.
The only way out is to do a hard reset.
>Fix:
Unknown. I wonder if this is a known problem, if anyone else is
working on it, and if it would make sense for me to try the same
under FreeBSD-stable to see if I get the same behavior.

>Audit-Trail:
>Unformatted: