ocfs2: update truncate handling of partial clusters

The partial cluster zeroing code used during truncate usually assumes that
the rightmost byte in the range to be zeroed lies on a cluster boundary.
This makes sense for truncate, but punching holes might require zeroing on
non-aligned rightmost boundaries.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

diff --cc fs/ocfs2/alloc.c
Simple merge

diff --cc fs/ocfs2/alloc.h
Simple merge

diff --cc fs/ocfs2/file.c
Simple merge