Licensing for the filesystem drivers is complex. Three different licenses
apply to various parts of the code:

* Christoph Pfisterer's original file system wrapper (FSW) code is covered
  by a BSD-style license. Many of the source files with names that take the
  form fsw_*.[ch] are so licensed, but this is NOT generally true of
  filesystem-specific files (e.g., fsw_ext2.c or fsw_btrfs.c).

* Certain filesystem drivers are licensed under the GPLv2, either because
  they borrow code from the Linux kernel or because a developer (typically
  Oracle) applied the GPLv2 license to them. This is true of the ext2fs,
  ext4fs, ReiserFS, HFS+, and ISO-9660 drivers.

* At least one filesystem driver (Btrfs) uses code taken from GRUB, and so
  uses the GPLv3 (or later) license.

Note that the GPLv2 and GPLv3 are, ironically, not compatible licenses.
Thus, code from GPLv2 and GPLv3 projects should not be mixed. The BSD
license used by Pfisterer's original code is compatible with both versions
of the GPL, so the fact that both GPLv2 and GPLv3 drivers is built upon it
is OK. If you intend to contribute to this project's drivers or use the
code yourself, please keep this fact in mind.

The below was written by Christoph Pfisterer with respect to his original
code:

 File System Wrapper License
=============================

The various parts of the File System Wrapper source code come from
different sources and may carry different licenses. Here's a quick
account of the situation:

 * The core code was written from scratch and is covered by a
   BSD-style license.

 * The EFI host driver was written from scratch, possibly using code
   from the TianoCore project and Intel's EFI Application Toolkit. It
   is covered by a BSD-style license.

 * The ext2 and reiserfs file system drivers use definitions from the
   Linux kernel source. The actual code was written from scratch,
   using multiple sources for reference. These drivers are covered by
   the GNU GPL.

For more details, see each file's boilerplate comment. The full text
of the GNU GPL is in the file LICENSE_GPL.txt.
