missing-parentheses bug, but this exposed a misplaced vfs_busy_pages().
This bug cost a factor of 2.5-3 in nfsv3 write performance! It should
be fixed in 2.2.
Removed some debugging code that gets triggered often in normal
operation. There are still many backwards diagnostics (#define
DIAGNOSTIC gives no diagnostics).
Submitted by: vfs_busy_pages() fix by dfr