From f0a747d129685b618ee89c973d4fe625c1cd291f Mon Sep 17 00:00:00 2001
From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Wed, 29 Jan 2020 01:51:21 +0000
Subject: [PATCH] vfs: add VNPASS macro and augment VNASSERT to print more
 about the assert

Sample out put now instead of mere VNASSERT failed:
VNASSERT failed: vp->v_holdcnt == 1234 not true at /usr/src/sys/kern/vfs_subr.c:3148 (vputx)

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D23396
---
 sys/sys/systm.h | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index dc95f26dc9af..628dd4e0f5b1 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -107,16 +107,24 @@ void	kassert_panic(const char *fmt, ...)  __printflike(1, 2);
 } while (0)
 #define	VNASSERT(exp, vp, msg) do {					\
 	if (__predict_false(!(exp))) {					\
-		vn_printf(vp, "VNASSERT failed\n");			\
+		vn_printf(vp, "VNASSERT failed: %s not true at %s:%d (%s)\n",\
+		   #exp, __FILE__, __LINE__, __func__);	 		\
 		kassert_panic msg;					\
 	}								\
 } while (0)
+#define	VNPASS(exp, vp)	do {						\
+	const char *_exp = #exp;					\
+	VNASSERT(exp, vp, ("condition %s not met at %s:%d (%s)",	\
+	    _exp, __FILE__, __LINE__, __func__));			\
+} while (0)
 #else
 #define	KASSERT(exp,msg) do { \
 } while (0)
 
 #define	VNASSERT(exp, vp, msg) do { \
 } while (0)
+#define	VNPASS(exp, vp) do { \
+} while (0)
 #endif
 
 #ifndef CTASSERT	/* Allow lint to override */