Fix deadlock in getOpenFileData() caused by taking the same RLock

twice.

fuse/pathfilesystem.go

@@ -259,7 +259,8 @@ func (me *inode) GetFullPath() (path string) {
 
 // GetPath returns the path relative to the mount governing this
 // inode.  It returns nil for mount if the file was deleted or the
-// filesystem unmounted.
+// filesystem unmounted.  This will take the treeLock for the mount,
+// so it can not be used in internal methods.
 func (me *inode) GetPath() (path string, mount *fileSystemMount) {
 	me.treeLock.RLock()
 	defer me.treeLock.RUnlock()
@@ -660,9 +661,6 @@ func (me *FileSystemConnector) unsafeUnmountNode(node *inode) {
 
 func (me *FileSystemConnector) getOpenFileData(nodeid uint64, fh uint64) (f File, m *fileSystemMount, p string, node *inode) {
 	node = me.getInodeData(nodeid)
-	node.treeLock.RLock()
-	defer node.treeLock.RUnlock()
-
 	if fh != 0 {
 		opened := me.getOpenedFile(fh)
 		m = opened.fileSystemMount