To provide real POSIX semantics, need components for:

- class to provide per-open interface from inode interface

- security attribute registration/checking mechanism

- file lock management

- special file node management (fifo, dev, etc.)

- stat information: timestamps, device/inode numbers, nlink


Caveats on the FS readers:

- absolute symbolic links are interpreted relative to the root of the FS,
  since the FS readers have no notion of a "global root".

- (ext2) the "sb" option is not supported, the super block is assumed to be
  at block 1.

- (minix) untested