ocfs2: Support creation of unwritten extents

This can now be trivially supported with re-use of our existing extend code.

ocfs2_allocate_unwritten_extents() takes a start offset and a byte length
and iterates over the inode, adding extents (marked as unwritten) until len
is reached. Existing extents are skipped over.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c441ef1..0d5fdde 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -368,7 +368,7 @@
 		u32 offset = OCFS2_I(dir)->ip_clusters;
 
 		status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,
-						    1, parent_fe_bh, handle,
+						    1, 0, parent_fe_bh, handle,
 						    data_ac, meta_ac, NULL);
 		BUG_ON(status == -EAGAIN);
 		if (status < 0) {