+/*
+ * On disk slot map for OCFS2. This defines the contents of the "slot_map"
+ * system file. A slot is valid if it contains a node number >= 0. The
+ * value -1 (0xFFFF) is OCFS2_INVALID_SLOT. This marks a slot empty.
+ */
+struct ocfs2_slot_map {
+/*00*/ __le16 sm_slots[0];
+/*
+ * Actual on-disk size is one block. OCFS2_MAX_SLOTS is 255,
+ * 255 * sizeof(__le16) == 512B, within the 512B block minimum blocksize.
+ */
+};
+
+struct ocfs2_extended_slot {
+/*00*/ __u8 es_valid;
+ __u8 es_reserved1[3];
+ __le32 es_node_num;
+/*10*/
+};
+
+/*
+ * The extended slot map, used when OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP
+ * is set. It separates out the valid marker from the node number, and
+ * has room to grow. Unlike the old slot map, this format is defined by
+ * i_size.
+ */
+struct ocfs2_slot_map_extended {
+/*00*/ struct ocfs2_extended_slot se_slots[0];
+/*
+ * Actual size is i_size of the slot_map system file. It should
+ * match s_max_slots * sizeof(struct ocfs2_extended_slot)
+ */
+};
+
+struct ocfs2_cluster_info {
+/*00*/ __u8 ci_stack[OCFS2_STACK_LABEL_LEN];
+ __le32 ci_reserved;
+/*08*/ __u8 ci_cluster[OCFS2_CLUSTER_NAME_LEN];
+/*18*/
+};
+