There is no valid reason why we can't support "nobh" option for filesystems
with blocksize != PAGESIZE.

This patch lets them use "nobh" option for writeback mode for blocksize <
pagesize.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>