Index: head/sys/kern/vfs_subr.c
===================================================================
--- head/sys/kern/vfs_subr.c
+++ head/sys/kern/vfs_subr.c
@@ -4395,6 +4395,9 @@
 
 	CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
 
+	if ((mp->mnt_kern_flag & MNTK_NOMSYNC) != 0)
+		return;
+
 	MNT_VNODE_FOREACH_ACTIVE(vp, mp, mvp) {
 		obj = vp->v_object;
 		if (obj != NULL && (obj->flags & OBJ_MIGHTBEDIRTY) != 0 &&
Index: head/sys/sys/mount.h
===================================================================
--- head/sys/sys/mount.h
+++ head/sys/sys/mount.h
@@ -396,6 +396,7 @@
 #define MNTK_UNMOUNTF	0x00000001	/* forced unmount in progress */
 #define MNTK_ASYNC	0x00000002	/* filtered async flag */
 #define MNTK_SOFTDEP	0x00000004	/* async disabled by softdep */
+#define MNTK_NOMSYNC	0x00000008	/* don't do vfs_msync */
 #define	MNTK_DRAINING	0x00000010	/* lock draining is happening */
 #define	MNTK_REFEXPIRE	0x00000020	/* refcount expiring is happening */
 #define MNTK_EXTENDED_SHARED	0x00000040 /* Allow shared locking for more ops */