Merge pull request #638 from hmsdao/patch-fixpath

Added long paths fix for samba network shares

src/restic/fs/file.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 )
 
 // File is an open file on a file system.
@@ -26,7 +27,20 @@ func fixpath(name string) string {
 	if runtime.GOOS == "windows" {
 		abspath, err := filepath.Abs(name)
 		if err == nil {
-			return "\\\\?\\" + abspath
+			// Check if \\?\UNC\ already exist
+			if strings.HasPrefix(abspath, `\\?\UNC\`) {
+				return abspath
+			}
+			// Check if \\?\ already exist
+			if strings.HasPrefix(abspath, `\\?\`) {
+				return abspath
+			}
+			// Check if path starts with \\
+			if strings.HasPrefix(abspath, `\\`) {
+				return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
+			}
+			// Normal path
+			return `\\?\` + abspath
 		}
 	}
 	return name