This patch adds "-o bh" option to force use of buffer_heads.  This option
is needed when we make "nobh" as default - and if we run into problems.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>