The following reply was made to PR kern/34882; it has been noted by GNATS.

From: "Julio M. Merino Vidal" <jmmv84@gmail.com>
To: "YAMAMOTO Takashi" <yamt@mwd.biglobe.ne.jp>
Cc: tech-kern@netbsd.org, gnats-bugs@NetBSD.org
Subject: Re: Use vn_rdwr in vnd (Re: kern/34882)
Date: Sat, 11 Nov 2006 12:40:03 +0100

 On 11/11/06, YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp> wrote:
 > > > > > i don't know how read requests with B_VFLUSH happens
 > > > >
 > > > > Just try a newfs over the vnd device and you'll get into
 > > > > handle_with_rw with B_READ and B_VFLUSH set.
 > > >
 > > > i tried the following with the attached patch, but got no panics.
 > > >
 > > >                 mount_tmpfs a /mnt
 > > >                 cd /mnt
 > > >                 dd if=/dev/zero of=x bs=1m count=1
 > > >                 vnconfig vnd0 x
 > > >                 newfs -F /dev/rvnd0d
 > >
 > > Of course not because that's what the increment of numoutput is for
 > > (or was supposed to be for).
 >
 > i meant i didn't get the panic in a patch attached in my previous mail.
 
 Oh, I'm sorry.  Didn't notice it.
 
 > >       printf("%s, %s\n", doread ? "read" : "write",
 > >           obp->b_flags & B_VFLUSH ? "flush" : "noflush");
 > >       if (!doread)
 > >               vp->v_numoutput++;
 > >
 > > And it does not panic.  I'm sure it did before!  And I'm sure I got
 > > "read, sync" messages from the debug printf.  (But maybe it was
 > > because I still had some other problem somewhere in the handling of
 > > petitions.)
 >
 > do you mean "read, flush" ?
 
 Yep.
 
 > > So... should I remove all the B_VFLUSH handling from the function?
 > > Should I change the manual v_numoutput increment to use the
 > > V_INCR_NUMOUTPUT macro?
 >
 > yes and yes.  afaik, B_VFLUSH is not something which vnd should care.
 
 OK, will do that later today.
 
 -- 
 Julio M. Merino Vidal <jmmv84@gmail.com>
 The Julipedia - http://julipedia.blogspot.com/