From d132dc7640a2177681372611b8c90b2593d59391 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Fri, 9 Dec 2016 15:41:09 +0000
Subject: [PATCH] drive: make DirMove more efficient and complain about moving
 the root

---
 drive/drive.go | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drive/drive.go b/drive/drive.go
index 14039a7b1..ec4b57d94 100644
--- a/drive/drive.go
+++ b/drive/drive.go
@@ -771,12 +771,16 @@ func (f *Fs) DirMove(src fs.Fs) error {
 	}
 
 	// Check if destination exists
-	f.dirCache.ResetRoot()
-	err := f.dirCache.FindRoot(false)
-	if err == nil {
+	if f.dirCache.FoundRoot() {
 		return fs.ErrorDirExists
 	}
 
+	// Refuse to move to or from the root
+	if f.root == "" || srcFs.root == "" {
+		fs.Debug(src, "DirMove error: Can't move root")
+		return errors.New("can't move root directory")
+	}
+
 	// Find ID of parent
 	leaf, directoryID, err := f.dirCache.FindPath(f.root, true)
 	if err != nil {