dlm: add node slots and generation

Slot numbers are assigned to nodes when they join the lockspace.
The slot number chosen is the minimum unused value starting at 1.
Once a node is assigned a slot, that slot number will not change
while the node remains a lockspace member.  If the node leaves
and rejoins it can be assigned a new slot number.

A new generation number is also added to a lockspace.  It is
set and incremented during each recovery along with the slot
collection/assignment.

The slot numbers will be passed to gfs2 which will use them as
journal id's.

Signed-off-by: David Teigland <[email protected]>

fs/dlm/dlm_internal.h

@@ -117,6 +117,18 @@ struct dlm_member {
 	struct list_head	list;
 	int			nodeid;
 	int			weight;
+	int			slot;
+	int			slot_prev;
+	uint32_t		generation;
+};
+
+/*
+ * low nodeid saves array of these in ls_slots
+ */
+
+struct dlm_slot {
+	int			nodeid;
+	int			slot;
 };
 
 /*
@@ -337,7 +349,9 @@ static inline int rsb_flag(struct dlm_rsb *r, enum rsb_flags flag)
 /* dlm_header is first element of all structs sent between nodes */
 
 #define DLM_HEADER_MAJOR	0x00030000
-#define DLM_HEADER_MINOR	0x00000000
+#define DLM_HEADER_MINOR	0x00000001
+
+#define DLM_HEADER_SLOTS	0x00000001
 
 #define DLM_MSG			1
 #define DLM_RCOM		2
@@ -425,10 +439,34 @@ union dlm_packet {
 	struct dlm_rcom		rcom;
 };
 
+#define DLM_RSF_NEED_SLOTS	0x00000001
+
+/* RCOM_STATUS data */
+struct rcom_status {
+	__le32			rs_flags;
+	__le32			rs_unused1;
+	__le64			rs_unused2;
+};
+
+/* RCOM_STATUS_REPLY data */
 struct rcom_config {
 	__le32			rf_lvblen;
 	__le32			rf_lsflags;
-	__le64			rf_unused;
+
+	/* DLM_HEADER_SLOTS adds: */
+	__le32			rf_flags;
+	__le16			rf_our_slot;
+	__le16			rf_num_slots;
+	__le32			rf_generation;
+	__le32			rf_unused1;
+	__le64			rf_unused2;
+};
+
+struct rcom_slot {
+	__le32			ro_nodeid;
+	__le16			ro_slot;
+	__le16			ro_unused1;
+	__le64			ro_unused2;
 };
 
 struct rcom_lock {
@@ -455,6 +493,7 @@ struct dlm_ls {
 	struct list_head	ls_list;	/* list of lockspaces */
 	dlm_lockspace_t		*ls_local_handle;
 	uint32_t		ls_global_id;	/* global unique lockspace ID */
+	uint32_t		ls_generation;
 	uint32_t		ls_exflags;
 	int			ls_lvblen;
 	int			ls_count;	/* refcount of processes in
@@ -493,6 +532,11 @@ struct dlm_ls {
 	int			ls_total_weight;
 	int			*ls_node_array;
 
+	int			ls_slot;
+	int			ls_num_slots;
+	int			ls_slots_size;
+	struct dlm_slot		*ls_slots;
+
 	struct dlm_rsb		ls_stub_rsb;	/* for returning errors */
 	struct dlm_lkb		ls_stub_lkb;	/* for returning errors */
 	struct dlm_message	ls_stub_ms;	/* for faking a reply */

fs/dlm/lockspace.c

@@ -525,6 +525,11 @@ static int new_lockspace(const char *name, int namelen, void **lockspace,
 	if (!ls->ls_recover_buf)
 		goto out_dirfree;
 
+	ls->ls_slot = 0;
+	ls->ls_num_slots = 0;
+	ls->ls_slots_size = 0;
+	ls->ls_slots = NULL;
+
 	INIT_LIST_HEAD(&ls->ls_recover_list);
 	spin_lock_init(&ls->ls_recover_list_lock);
 	ls->ls_recover_list_count = 0;