ocfs2: Use ocfs2_extent_list instead of ocfs2_dinode.

ocfs2_extend_meta_needed(), ocfs2_calc_extend_credits() and
ocfs2_reserve_new_metadata() are all useful for extent tree operations. But
they are all limited to an inode btree because they use a struct
ocfs2_dinode parameter. Change their parameter to struct ocfs2_extent_list
(the part of an ocfs2_dinode they actually use) so that the xattr btree code
can use these functions.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 377acb2..dc36cd1 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -4527,7 +4527,8 @@
 	} else
 		rightmost_el = path_leaf_el(path);
 
-	credits += path->p_tree_depth + ocfs2_extend_meta_needed(di);
+	credits += path->p_tree_depth +
+		   ocfs2_extend_meta_needed(&di->id2.i_list);
 	ret = ocfs2_extend_trans(handle, credits);
 	if (ret) {
 		mlog_errno(ret);