Feel free to add whatever occurs to you by finishing the sentence 'VFS needs ...'
vfs composition: the ability to stack vfs on top of one another, ala Plan 9. It's got it, Cache VFS - complete with write-back. -- 20040612 CMcC
versioning vfs: write to a file, and the diffs are store and accessed by globbing the file as if it were a directory. People have got to realise that the distinction between file and directory is a purely arbitrary and not particularly useful constraint. -- 20040612 CMcC