1. In a computer system having a subject filesystem and corresponding stacking filesystem, a method for handling directory names comprising: obtaining directory trees of the subject filesystem, each directory tree having a root directory entry and plural directory entries linked together in a hierarchical manner, each directory entry having a respective directory name, the subject filesystem having a real root directory different then the root directory entry of each directory tree as obtained; for each directory entry, representing the directory entry with a respective filesystem object, filesystem objects in the stacking filesystem having respective virtual directory names; using the directory trees of the subject filesystem for filesystem objects not contained in the stacking filesystem to process operations such that operations are processed using directory names in a name space of the subject filesystem free of interference from the virtual directory names of the stacking filesystem; and wherein the step of using the directory trees of the subject filesystem further includes mismatch free handling of directory names, relative to the virtual directory names of the stacking filesystem, by employing one or more alias directory entries and wherein each alias directory entry has a respective support structure defining a per process root context in which a root directory entry of a process is set to an alias directory entry that resolves to the real root directory entry of the subject filesystem, resulting in a mismatch free handling of directory names.