Deadlock with umount -f involving tmpfs on top of ZFS on r271170

[Peter Holm]

On Wed, Sep 24, 2014 at 04:47:25PM +0300, Konstantin Belousov wrote:
> On Wed, Sep 24, 2014 at 03:26:05PM +0200, Peter Holm wrote:
> > The patch is an improvement, but:
> > 
> > http://people.freebsd.org/~pho/stress/log/kostik718.txt
> 
> Does you load included both rename and link, or only one of those
> syscalls ?  I see a bug in the rename part of the patch, below is
> the update.
> 

Both. I have split the tests in two now. Uptime is by now one hour.
I'll let that run for a few hours more, before switching to random
tests.

I did get this page fault once:
http://people.freebsd.org/~pho/stress/log/kostik719.txt
but I guess it's unrelated? I have recompiled uma_core.c and
vm_pageout with "-O0" in case it shows up again.

- Peter