From e76357cb57ee597d2a08cd79df3cdb131eceef91 Mon Sep 17 00:00:00 2001
From: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Date: Tue, 18 Jul 2017 10:33:29 +0000
Subject: [PATCH] btrfs: improve an error string

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
---
 snapshot/btrfs/btrfs.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/snapshot/btrfs/btrfs.go b/snapshot/btrfs/btrfs.go
index 4f3ba6dfc..fee9a3c40 100644
--- a/snapshot/btrfs/btrfs.go
+++ b/snapshot/btrfs/btrfs.go
@@ -54,7 +54,7 @@ func NewSnapshotter(root string) (snapshot.Snapshotter, error) {
 		return nil, err
 	}
 	if mnt.FSType != "btrfs" {
-		return nil, fmt.Errorf("expected btrfs, got %s", mnt.FSType)
+		return nil, fmt.Errorf("path %s must be a btrfs filesystem to be used with the btrfs snapshotter", root)
 	}
 	var (
 		active    = filepath.Join(root, "active")