ocfs2: Define data structures for discontiguous block groups.

Defines the OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG feature bit and modifies
struct ocfs2_group_desc for the feature.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Tao Ma <tao.ma@oracle.com>
diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index 63c41e2..9538bbe 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -122,7 +122,7 @@
 	struct super_block *sb = osb->sb;
 
 	gd_mb = ocfs2_clusters_to_megabytes(osb->sb,
-					    8 * ocfs2_group_bitmap_size(sb));
+					    8 * ocfs2_group_bitmap_size(sb, 0));
 
 	/*
 	 * This takes care of files systems with very small group