[src/trunk]: src/sys/nfs Add diagnostic check which hits when PR 42455 is rep...

[cegger <cegger%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/082355f079d2
branches:  trunk
changeset: 758212:082355f079d2
user:      cegger <cegger%NetBSD.org@localhost>
date:      Tue Oct 26 11:44:53 2010 +0000

description:
Add diagnostic check which hits when PR 42455 is reproduced.
Idea from hans@

diffstat:

 sys/nfs/nfs_vnops.c |  12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diffs (33 lines):

diff -r 25358a55dd0f -r 082355f079d2 sys/nfs/nfs_vnops.c
--- a/sys/nfs/nfs_vnops.c       Tue Oct 26 09:13:54 2010 +0000
+++ b/sys/nfs/nfs_vnops.c       Tue Oct 26 11:44:53 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nfs_vnops.c,v 1.284 2010/06/24 13:03:17 hannken Exp $  */
+/*     $NetBSD: nfs_vnops.c,v 1.285 2010/10/26 11:44:53 cegger Exp $   */
 
 /*
  * Copyright (c) 1989, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nfs_vnops.c,v 1.284 2010/06/24 13:03:17 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nfs_vnops.c,v 1.285 2010/10/26 11:44:53 cegger Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_nfs.h"
@@ -1378,6 +1378,14 @@
                if (v3) {
                        wccflag = NFSV3_WCCCHK;
                        nfsm_wcc_data(vp, wccflag, NAC_NOTRUNC, !error);
+
+                       /* Diagnostic check: The KASSERT hits when PR 42455
+                        * is reproduced.
+                        */
+                       if (ctx.nwc_mbufcount >= 2) {
+                               KASSERT(mb->m_next != NULL);
+                       }
+
                        if (!error) {
                                nfsm_dissect(tl, u_int32_t *, 2 * NFSX_UNSIGNED
                                        + NFSX_V3WRITEVERF);