diff --git a/sys/fs/nfsclient/nfs_clvnops.c b/sys/fs/nfsclient/nfs_clvnops.c
--- a/sys/fs/nfsclient/nfs_clvnops.c
+++ b/sys/fs/nfsclient/nfs_clvnops.c
@@ -4111,14 +4111,6 @@
 	int attrflag, content, error, ret;
 	bool eof = false;			/* shut up compiler. */
 
-	if (vp->v_type != VREG)
-		return (ENOTTY);
-	nmp = VFSTONFS(vp->v_mount);
-	if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION) {
-		error = vop_stdioctl(ap);
-		return (error);
-	}
-
 	/* Do the actual NFSv4.2 RPC. */
 	switch (ap->a_command) {
 	case FIOSEEKDATA:
@@ -4134,6 +4126,18 @@
 	error = vn_lock(vp, LK_SHARED);
 	if (error != 0)
 		return (EBADF);
+
+	if (vp->v_type != VREG) {
+		VOP_UNLOCK(vp);
+		return (ENOTTY);
+	}
+	nmp = VFSTONFS(vp->v_mount);
+	if (!NFSHASNFSV4(nmp) || nmp->nm_minorvers < NFSV42_MINORVERSION) {
+		VOP_UNLOCK(vp);
+		error = vop_stdioctl(ap);
+		return (error);
+	}
+
 	attrflag = 0;
 	if (*((off_t *)ap->a_data) >= VTONFS(vp)->n_size)
 		error = ENXIO;