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Subject: Re: Real-time rw-locks (Re: [patch] Real-Time Preemption,
	-RT-2.6.10-rc2-mm3-V0.7.32-15)
From: Lee Revell <rlrevell@joe-job.com>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Ingo Molnar <mingo@elte.hu>, Esben Nielsen <simlo@phys.au.dk>,
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Date: Fri, 28 Jan 2005 16:13:15 -0500
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On Fri, 2005-01-28 at 11:18 -0800, Trond Myklebust wrote:
> In the NFS client code we may use rwsems in order to protect stateful
> operations against the (very infrequently used) server reboot recovery
> code. The point is that when the server reboots, the server forces us to
> block *all* requests that involve adding new state (e.g. opening an
> NFSv4 file, or setting up a lock) while our client and others are
> re-establishing their existing state on the server.

Hmm, when I was an ISP sysadmin I used to use this all the time.  NFS
mounts from the BSD/OS clients would start to act up under heavy web
server load and the cleanest way to get them to recover was to simulate
a reboot on the NetApp.  Of course Linux clients were unaffected, they
were just along for the ride ;-)

Lee