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From: Mark Felder <feld@FreeBSD.org>
To: Rick Macklem <rmacklem@uoguelph.ca>
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Subject: Re: fixing "umount -f" for the NFS client
Date: Thu, 29 Aug 2013 07:52:50 -0500
Cc: freebsd-fs@freebsd.org
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On Thu, Aug 29, 2013, at 7:50, Rick Macklem wrote:
> 
> Finally, neither of these options are safe to use for NFSv4, because
> operations that manipulate state (like locks) cannot be safely
> interrupted,
> since they will leave the lock in an undefined state, at least for the
> FreeBSD server.
> So, at least for NFSv4, a forced dismount is a necessary alternative.
> 

I was not aware of this specific issue, so thank you for the warning