--- fs/nfsclient/nfs_clvnops.c.text	2017-03-16 21:55:16.263393000 -0400
+++ fs/nfsclient/nfs_clvnops.c	2017-03-17 09:31:23.632814000 -0400
@@ -140,6 +140,7 @@ static vop_advlock_t	nfs_advlock;
 static vop_advlockasync_t nfs_advlockasync;
 static vop_getacl_t nfs_getacl;
 static vop_setacl_t nfs_setacl;
+static vop_set_text_t nfs_set_text;
 
 /*
  * Global vfs data structures for nfs
@@ -176,6 +177,7 @@ struct vop_vector newnfs_vnodeops = {
 	.vop_write =		ncl_write,
 	.vop_getacl =		nfs_getacl,
 	.vop_setacl =		nfs_setacl,
+	.vop_set_text =		nfs_set_text,
 };
 
 struct vop_vector newnfs_fifoops = {
@@ -3373,6 +3375,29 @@ nfs_setacl(struct vop_setacl_args *ap)
 	return (error);
 }
 
+static int
+nfs_set_text(struct vop_set_text_args *ap)
+{
+	struct vnode *vp = ap->a_vp;
+	struct nfsnode *np;
+
+	/*
+	 * If the text file has been mmap'd, the dirty pages must be flushed
+	 * so that the modify time of the file will be up to date.
+	 */
+	if (vp->v_object != NULL) {
+		np = VTONFS(vp);
+		VM_OBJECT_WLOCK(vp->v_object);
+		vm_object_page_clean(vp->v_object, 0, 0, OBJPC_SYNC);
+		VM_OBJECT_WUNLOCK(vp->v_object);
+		mtx_lock(&np->n_mtx);
+		np->n_mtime = np->n_vattr.na_mtime;
+		mtx_unlock(&np->n_mtx);
+	}
+	vp->v_vflag |= VV_TEXT;
+	return (0);
+}
+
 /*
  * Return POSIX pathconf information applicable to nfs filesystems.
  */