ocfs2/o2hb: check len for bio_add_page() to avoid getting incorrect bio

ocfs2/o2hb: check len for bio_add_page() to avoid getting incorrect bio

We need to check len for bio_add_page() to make sure the bio has been
set up correctly, otherwise we may submit incorrect data to device.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jun Piao <[email protected]>
Reviewed-by: Yiwen Jiang <[email protected]>
Reviewed-by: Changwei Ge <[email protected]>
Acked-by: Joseph Qi <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Changwei Ge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>