From: Galen Michael Elias <gme@citi.umich.edu>

  This patch fixes two places where the handling of page boundaries was
incorrect and caused to IO_ERR's when it shouldn't have.

1.  In decode_write it was just a small typo.
2.  In decode_compound we avoid using READ_BUF, but don't provide all of
it's functionality, specifically crosses a page boundary.