Index: share/man/man9/vref.9
===================================================================
--- share/man/man9/vref.9
+++ share/man/man9/vref.9
@@ -28,17 +28,19 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 24, 1996
+.Dd January 14, 2016
 .Dt VREF 9
 .Os
 .Sh NAME
-.Nm vref
+.Nm vref , vrefl
 .Nd increment the use count for a vnode
 .Sh SYNOPSIS
 .In sys/param.h
 .In sys/vnode.h
 .Ft void
 .Fn vref "struct vnode *vp"
+.Ft void
+.Fn vrefl "struct vnode *vp"
 .Sh DESCRIPTION
 Increment the
 .Va v_usecount
@@ -56,7 +58,14 @@
 Any code in the system which is using a vnode (e.g.\& during the
 operation of some algorithm or to store in a data structure) should
 call
-.Fn vref .
+.Fn vref
+or
+.Fn vrefl .
+.Pp
+.Fn vref
+locks the vnode interlock while
+.Fn vrefl
+expects the interlock to already be held.
 .Sh SEE ALSO
 .Xr vget 9 ,
 .Xr vnode 9 ,
Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c
+++ sys/kern/vfs_subr.c
@@ -103,7 +103,7 @@
 static void	syncer_shutdown(void *arg, int howto);
 static int	vtryrecycle(struct vnode *vp);
 static void	v_init_counters(struct vnode *);
-static void	v_incr_usecount(struct vnode *);
+static void	v_incr_usecount(struct vnode *, bool);
 static void	v_incr_devcount(struct vnode *);
 static void	v_decr_devcount(struct vnode *);
 static void	vnlru_free(int);
@@ -2377,14 +2377,18 @@
  * the vnode from the free list if it is presently free.
  */
 static void
-v_incr_usecount(struct vnode *vp)
+v_incr_usecount(struct vnode *vp, bool locked)
 {
 
-	ASSERT_VI_UNLOCKED(vp, __func__);
+	if (locked)
+		ASSERT_VI_LOCKED(vp, __func__);
+	else
+		ASSERT_VI_UNLOCKED(vp, __func__);
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 
 	if (vp->v_type == VCHR) {
-		VI_LOCK(vp);
+		if (!locked)
+			VI_LOCK(vp);
 		_vhold(vp, true);
 		if (vp->v_iflag & VI_OWEINACT) {
 			VNASSERT(vp->v_usecount == 0, vp,
@@ -2393,20 +2397,23 @@
 		}
 		refcount_acquire(&vp->v_usecount);
 		v_incr_devcount(vp);
-		VI_UNLOCK(vp);
+		if (!locked)
+			VI_LOCK(vp);
 		return;
 	}
 
-	_vhold(vp, false);
+	_vhold(vp, locked);
 	if (vfs_refcount_acquire_if_not_zero(&vp->v_usecount)) {
 		VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
 		    ("vnode with usecount and VI_OWEINACT set"));
 	} else {
-		VI_LOCK(vp);
+		if (!locked)
+			VI_LOCK(vp);
 		if (vp->v_iflag & VI_OWEINACT)
 			vp->v_iflag &= ~VI_OWEINACT;
 		refcount_acquire(&vp->v_usecount);
-		VI_UNLOCK(vp);
+		if (!locked)
+			VI_UNLOCK(vp);
 	}
 }
 
@@ -2519,8 +2526,14 @@
 vref(struct vnode *vp)
 {
 
-	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
-	v_incr_usecount(vp);
+	v_incr_usecount(vp, false);
+}
+
+void
+vrefl(struct vnode *vp)
+{
+
+	v_incr_usecount(vp, true);
 }
 
 /*
Index: sys/sys/vnode.h
===================================================================
--- sys/sys/vnode.h
+++ sys/sys/vnode.h
@@ -823,6 +823,7 @@
 void	vput(struct vnode *vp);
 void	vrele(struct vnode *vp);
 void	vref(struct vnode *vp);
+void	vrefl(struct vnode *vp);
 int	vrefcnt(struct vnode *vp);
 void 	v_addpollinfo(struct vnode *vp);