diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -4018,6 +4018,9 @@
  * Both vnodes could be unlocked temporary (and reclaimed).
  *
  * If requesting shared locking, locked vnode lock must not be recursed.
+ *
+ * Only one of LK_SHARED and LK_EXCLUSIVE must be specified.
+ * LK_NODDLKTREAT can be optionally passed.
  */
 void
 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1,
@@ -4025,19 +4028,21 @@
 {
 	int error;
 
-	MPASS(lkflags1 == LK_SHARED || lkflags1 == LK_EXCLUSIVE);
-	MPASS(lkflags2 == LK_SHARED || lkflags2 == LK_EXCLUSIVE);
+	MPASS((lkflags1 & LK_SHARED) != 0 ^ (lkflags1 & LK_EXCLUSIVE) != 0);
+	MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0);
+	MPASS((lkflags2 & LK_SHARED) != 0 ^ (lkflags2 & LK_EXCLUSIVE) != 0);
+	MPASS((lkflags2 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0);
 
 	if (vp1 == NULL && vp2 == NULL)
 		return;
 
 	if (vp1 != NULL) {
-		if (lkflags1 == LK_SHARED &&
+		if ((lkflags1 & LK_SHARED) != 0 &&
 		    (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0)
-			lkflags1 = LK_EXCLUSIVE;
+			lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE;
 		if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) {
 			ASSERT_VOP_LOCKED(vp1, "vp1");
-			if (lkflags1 == LK_EXCLUSIVE) {
+			if ((lkflags1 & LK_EXCLUSIVE) != 0) {
 				VOP_UNLOCK(vp1);
 				ASSERT_VOP_UNLOCKED(vp1,
 				    "vp1 shared recursed");
@@ -4050,12 +4055,12 @@
 	}
 
 	if (vp2 != NULL) {
-		if (lkflags2 == LK_SHARED &&
+		if ((lkflags2 & LK_SHARED) != 0 &&
 		    (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0)
-			lkflags2 = LK_EXCLUSIVE;
+			lkflags2 = (lkflags2 & ~LK_SHARED) | LK_EXCLUSIVE;
 		if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) {
 			ASSERT_VOP_LOCKED(vp2, "vp2");
-			if (lkflags2 == LK_EXCLUSIVE) {
+			if ((lkflags2 & LK_EXCLUSIVE) != 0) {
 				VOP_UNLOCK(vp2);
 				ASSERT_VOP_UNLOCKED(vp2,
 				    "vp2 shared recursed");