i386 hangs during halt "vnodes remaining... 0 time out"

[Tijl Coosemans]

On Sun, 22 Apr 2018 16:28:55 +0300 Konstantin Belousov <kostikbel at gmail.com> wrote:
> On Sun, Apr 22, 2018 at 03:15:00PM +0200, Tijl Coosemans wrote:
>> Thanks for the review.  There's just one concern I have.  With this patch
>> the bufspace_daemon threads appear to shutdown after the buf_daemon and
>> after the syncer because the event handlers are registered later.  Are
>> there any dependencies between these processes that require the bufspace
>> threads to be stopped earlier?  
> 
> I think for correctness bufdaemon must stop after the syncer, since syncer
> operation can cause a situation where bufdaemon help is needed to proceed.
> Other than this, the stop order is irrelevant, because after syncer
> finished, there should be no any further filesystem activity.

A quick way to do that would be to use SHUTDOWN_PRI_LAST + 100 for the
event handlers in the patch, like shutdown_conf in kern_shutdown.c
already does.  Is that acceptable here as well?