Re: [NetBSD 8.0] Another panic in ffs_newvnode()

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 10 Jul 2017 22:47:59 +0200
    From:        =?UTF-8?Q?BERTRAND_Jo=c3=abl?= <joel.bertrand%systella.fr@localhost>
    Message-ID:  <7123e2f9-e048-7ee1-9736-135fb2558db3%systella.fr@localhost>

  | mount -u -o sync /xxx

You probably do not really want to do that, while it will (well, should)
turn off async mode, sync is much more than that, and is rarely needed for
anything (that's "slow but safe" mode).   As Christos' message indicated,
the correct option would be noasync (similarly to turn off sync mode, and
revert to "normal" the option is "nosync" not "async").

  | 	On /usr and /var, system returns :
  | legendre# mount -u -o sync /var
  | mount_ffs: /dev/raid0f on /var: Device busy

Files are open for writing.   Hard to avoid on /var ... (not sure why /usr
would be similarly affected, but it does depend on what else is under there
and not separately mounted.)

  | Is there a way to remove async flag without rebooting ? I cannot access 
  | to this server until 20th of july.

It is likely that the problem you're having relates to an issue we have
discussed before, but didn't ever completely resolve.

That is, when you do an update mount, the flags specified are everything
that gets set, so
	mount -u -o noasync /var
is not just turning off the async flag, it is turning off everything
else as well (whatever is in fstab).   (There is a special case for
doing one particular update on the root, but that's not relevant here.)

Try

	mount -u -o noasync,log,rw /var

not sure it will work, but it might...

kre