diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index b80d03d0e9ec..d37e0662f266 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -353,6 +353,14 @@ vop_stdaccessx(struct vop_accessx_args *ap)
 	if (accmode == 0)
 		return (0);
 
+	/*
+	 * Many VOP_APPEND implementations don't expect VAPPEND without VWRITE
+	 * being set, e.g. they check whether the filesystem is read-only only
+	 * when VWRITE is set.  Make sure we don't confuse them.
+	 */
+	if (accmode & VAPPEND)
+		accmode |= VWRITE;
+
 	return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
 }