This is the Nemesis ext2fs code.

At the moment it is read-only; there are hooks for read-write, but
I need to think a lot more about how to implement it. Coming soon to
a tree near you...

Parts of this code have been stolen from linux, eg. the inode_bmap function.
Most of it is new.

Need to think MUCH more about mutexes; we have several threads
potentially running ext2fs code:

  USD fault handler
  Entry for client calls
  BinderCallback thread

For now, leave mutex stuff out...

