diff --git a/sys/fs/fuse/fuse_vnops.c b/sys/fs/fuse/fuse_vnops.c
--- a/sys/fs/fuse/fuse_vnops.c
+++ b/sys/fs/fuse/fuse_vnops.c
@@ -861,7 +861,7 @@
 	pid_t pid;
 	int err;
 
-	if (mp != vnode_mount(outvp))
+	if (mp == NULL || mp != vnode_mount(outvp))
 		goto fallback;
 
 	if (incred->cr_uid != outcred->cr_uid)
@@ -870,6 +870,7 @@
 	if (incred->cr_groups[0] != outcred->cr_groups[0])
 		goto fallback;
 
+	/* Caller busied mp, mnt_data can be safely accessed. */
 	if (fsess_not_impl(mp, FUSE_COPY_FILE_RANGE))
 		goto fallback;
 
@@ -879,23 +880,7 @@
 		td = ap->a_fsizetd;
 	pid = td->td_proc->p_pid;
 
-	/* Lock both vnodes, avoiding risk of deadlock. */
-	do {
-		err = vn_lock(outvp, LK_EXCLUSIVE);
-		if (invp == outvp)
-			break;
-		if (err == 0) {
-			err = vn_lock(invp, LK_SHARED | LK_NOWAIT);
-			if (err == 0)
-				break;
-			VOP_UNLOCK(outvp);
-			err = vn_lock(invp, LK_SHARED);
-			if (err == 0)
-				VOP_UNLOCK(invp);
-		}
-	} while (err == 0);
-	if (err != 0)
-		return (err);
+	vn_lock_pair(invp, false, LK_SHARED, outvp, false, LK_EXCLUSIVE);
 
 	err = fuse_filehandle_getrw(invp, FREAD, &infufh, incred, pid);
 	if (err)