Index: kern/vfs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_vnops.c,v
retrieving revision 1.258
diff -u -p -r1.258 vfs_vnops.c
--- kern/vfs_vnops.c	13 Jan 2008 14:44:11 -0000	1.258
+++ kern/vfs_vnops.c	23 Mar 2008 02:23:41 -0000
@@ -862,27 +862,21 @@ _vn_lock(struct vnode *vp, int flags, ch
 {
 	int error;
 
-	do {
+	/*
+	 * With no lock type requested we're just polling for validity.
+	 */
+	if ((flags & LK_TYPE_MASK) == 0) {
+		error = 0;
 		if ((flags & LK_INTERLOCK) == 0)
 			VI_LOCK(vp);
-		if ((flags & LK_NOWAIT || (flags & LK_TYPE_MASK) == 0) &&
-		    vp->v_iflag & VI_DOOMED) {
-			VI_UNLOCK(vp);
-			return (ENOENT);
-		}
-		/*
-		 * Just polling to check validity.
-		 */
-		if ((flags & LK_TYPE_MASK) == 0) {
-			VI_UNLOCK(vp);
-			return (0);
-		}
-		/*
-		 * lockmgr drops interlock before it will return for
-		 * any reason.  So force the code above to relock it.
-		 */
-		error = VOP_LOCK1(vp, flags | LK_INTERLOCK, file, line);
-		flags &= ~LK_INTERLOCK;
+		if (vp->v_iflag & VI_DOOMED)
+			error = ENOENT;
+		VI_UNLOCK(vp);
+		return (error);
+	}
+	do {
+		error = VOP_LOCK1(vp, flags, file, line);
+		flags &= ~LK_INTERLOCK;	/* Interlock is always dropped. */
 		KASSERT((flags & LK_RETRY) == 0 || error == 0,
 		    ("LK_RETRY set with incompatible flags %d\n", flags));
 		/*
Index: ufs/ffs/ffs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/ufs/ffs/ffs_vnops.c,v
retrieving revision 1.181
diff -u -p -r1.181 ffs_vnops.c
--- ufs/ffs/ffs_vnops.c	22 Mar 2008 09:15:16 -0000	1.181
+++ ufs/ffs/ffs_vnops.c	23 Mar 2008 02:23:41 -0000
@@ -361,16 +361,6 @@ ffs_lock(ap)
 		vp = ap->a_vp;
 		flags = ap->a_flags;
 		for (;;) {
-			/*
-			 * vnode interlock must be held to ensure that
-			 * the possibly external lock isn't freed,
-			 * e.g. when mutating from snapshot file vnode
-			 * to regular file vnode.
-			 */
-			if ((flags & LK_INTERLOCK) == 0) {
-				VI_LOCK(vp);
-				flags |= LK_INTERLOCK;
-			}
 			lkp = vp->v_vnlock;
 			result = _lockmgr_args(lkp, flags, VI_MTX(vp),
 			    LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT,
@@ -390,7 +380,6 @@ ffs_lock(ap)
 			    ap->a_file, ap->a_line);
 			if ((flags & LK_TYPE_MASK) == LK_UPGRADE)
 				flags = (flags & ~LK_TYPE_MASK) | LK_EXCLUSIVE;
-			flags &= ~LK_INTERLOCK;
 		}
 		break;
 	default: