diriv: handle directory rename over directory

If an empty directory is overwritten we will always get
ENOTEMPTY as the "empty" directory will still contain gocryptfs.diriv.
Handle that case by removing the target directory and trying again.

Fixes issue #10

pathfs_frontend/file.go

@@ -1,5 +1,7 @@
 package pathfs_frontend
 
+// FUSE operations on file handles
+
 import (
 	"bytes"
 	"fmt"

pathfs_frontend/file_holes.go

@@ -1,5 +1,7 @@
 package pathfs_frontend
 
+// Helper functions for sparse files (files with holes)
+
 import (
 	"github.com/hanwen/go-fuse/fuse"
 	"github.com/rfjakob/gocryptfs/cryptfs"

pathfs_frontend/fs.go

@@ -1,5 +1,7 @@
 package pathfs_frontend
 
+// FUSE operations on paths
+
 import (
 	"encoding/base64"
 	"os"
@@ -300,6 +302,17 @@ func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (cod
 	fs.CryptFS.DirIVCacheEnc.Clear()
 
 	err = os.Rename(cOldPath, cNewPath)
+
+	if lerr, ok := err.(*os.LinkError); ok && lerr.Err == syscall.ENOTEMPTY {
+		// If an empty directory is overwritten we will always get
+		// ENOTEMPTY as the "empty" directory will still contain gocryptfs.diriv.
+		// Handle that case by removing the target directory and trying again.
+		cryptfs.Debug.Printf("Rename: Handling ENOTEMPTY\n")
+		if fs.Rmdir(newPath, context) == fuse.OK {
+			err = os.Rename(cOldPath, cNewPath)
+		}
+	}
+
 	return fuse.ToStatus(err)
 }
 

pathfs_frontend/fs_dir.go

@@ -1,5 +1,7 @@
 package pathfs_frontend
 
+// Mkdir and Rmdir
+
 import (
 	"fmt"
 	"os"