From owner-freebsd-bugs  Sat Mar 22 23:56:21 1997
Return-Path: <owner-bugs>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id XAA28607
          for bugs-outgoing; Sat, 22 Mar 1997 23:56:21 -0800 (PST)
Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19])
          by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id XAA28601
          for <freebsd-bugs@freefall.freebsd.org>; Sat, 22 Mar 1997 23:56:17 -0800 (PST)
Received: (from bde@localhost) by godzilla.zeta.org.au (8.8.3/8.6.9) id SAA29091; Sun, 23 Mar 1997 18:53:16 +1100
Date: Sun, 23 Mar 1997 18:53:16 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199703230753.SAA29091@godzilla.zeta.org.au>
To: freebsd-bugs@freefall.freebsd.org, peter@spinner.DIALix.COM
Subject: Re: kern/3064: nfs server link() handler panics with non-recursive lock reentry
Sender: owner-bugs@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

> > >Fix:
> > 	
> > Not known.. I don't understand vnode locking under lite2 well enough.
> 
> It seems the panic is happening within VOP_LINK(), so nfsrv_link() doesn't 
> appear to be setting up the locking properly when the target file exists.  

It seems to be a simple merge error.  You understand merges? :-)  The args
are reversed, and exclusive locking of the directory arg is normal.

I'm still confused about the ordering.  nfssrv_link() uses non-Lite2 order
for NetBSD and FreeBSD; nfs_link() uses non-Lite2 order for NetBSD.  One of
the NetBSD cases is probably wrong.  CSRG reversed the order in Lite2.  I
thought that we reversed it too.  VOP_LINK.9 seems to agree with our actual
order (tdvp first).

Bruce

diff -c2 nfs_serv.c~ nfs_serv.c
*** nfs_serv.c~	Mon Feb 24 00:40:43 1997
--- nfs_serv.c	Sun Mar 23 18:32:53 1997
***************
*** 2028,2032 ****
  		nqsrv_getl(vp, ND_WRITE);
  		nqsrv_getl(xp, ND_WRITE);
! 		error = VOP_LINK(vp, nd.ni_dvp, &nd.ni_cnd);
  	} else {
  		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
--- 2026,2034 ----
  		nqsrv_getl(vp, ND_WRITE);
  		nqsrv_getl(xp, ND_WRITE);
! #if defined(__NetBSD__) || defined(__FreeBSD__)
! 		error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
! #else
!   		error = VOP_LINK(vp, nd.ni_dvp, &nd.ni_cnd);
! #endif
  	} else {
  		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);