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/alloc.c b/fs/ocfs2/alloc.c
index 0db6a1f..2e38983 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -3726,6 +3726,7 @@
 			u32 cpos,
 			u64 start_blk,
 			u32 new_clusters,
+			u8 flags,
 			struct ocfs2_alloc_context *meta_ac)
 {
 	int status;
@@ -3749,6 +3750,7 @@
 	rec.e_cpos = cpu_to_le32(cpos);
 	rec.e_blkno = cpu_to_le64(start_blk);
 	rec.e_leaf_clusters = cpu_to_le16(new_clusters);
+	rec.e_flags = flags;
 
 	status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
 					  &insert);