From 1723444ba2587a878605622f5c01188e578a97e9 Mon Sep 17 00:00:00 2001
From: Derek McGowan <derek@mcgstyle.net>
Date: Fri, 17 Feb 2017 18:43:10 -0800
Subject: [PATCH] snapshot/overlay: prevent committing view

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
---
 snapshot/overlay/overlay.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/snapshot/overlay/overlay.go b/snapshot/overlay/overlay.go
index 69f1c88..588aec2 100644
--- a/snapshot/overlay/overlay.go
+++ b/snapshot/overlay/overlay.go
@@ -253,6 +253,13 @@ func (a *activeDir) setParent(name string) error {
 }
 
 func (a *activeDir) commit(name string, c *cache) error {
+	if _, err := os.Stat(filepath.Join(a.path, "fs")); err != nil {
+		if os.IsNotExist(err) {
+			return errors.New("cannot commit view")
+		}
+		return err
+	}
+
 	// TODO(stevvooe): This doesn't quite meet the current model. The new model
 	// is to copy all of this out and let the transaction continue. We don't
 	// really have tests for it yet, but this will be the spot to fix it.