From: Christoph Hellwig <hch@lst.de>

Remove all the code now in the VFS, make XFS's freeze ioctls use the new
infastructure and reorganize some code.

This code needs some work so the source files shared with 2.4 aren't
exposed to the new VFS interfaces directly.  You'll get an update once this
has been discussed with the other XFS developers and is implemented.  Note
that the current patch works fine and I wouldn't complain if it gets into
Linus' tree as-is.