Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c
+++ sys/kern/vfs_vnops.c
@@ -2436,7 +2436,8 @@
 }
 
 int
-vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
+vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off,
+    struct ucred *cred)
 {
 	struct vattr va;
 	daddr_t bn, bnp;
@@ -2445,7 +2446,8 @@
 	int error;
 
 	KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
-	    ("Wrong command %lu", cmd));
+	    ("%s: Wrong command %lu", __func__, cmd));
+	ASSERT_VOP_LOCKED(vp, "vn_bmap_seekhole_locked");
 
 	if (vn_lock(vp, LK_SHARED) != 0)
 		return (EBADF);
@@ -2489,6 +2491,21 @@
 	return (error);
 }
 
+int
+vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
+{
+	int error;
+
+	KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
+	    ("%s: Wrong command %lu", __func__, cmd));
+
+	if (vn_lock(vp, LK_SHARED) != 0)
+		return (EBADF);
+	error = vn_bmap_seekhole_locked(vp, cmd, off, cred);
+	VOP_UNLOCK(vp);
+	return (error);
+}
+
 int
 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
 {
Index: sys/sys/vnode.h
===================================================================
--- sys/sys/vnode.h
+++ sys/sys/vnode.h
@@ -731,6 +731,8 @@
 void	vn_printf(struct vnode *vp, const char *fmt, ...) __printflike(2,3);
 int	vrecycle(struct vnode *vp);
 int	vrecyclel(struct vnode *vp);
+int	vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off,
+	    struct ucred *cred);
 int	vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off,
 	    struct ucred *cred);
 int	vn_close(struct vnode *vp,