7 files changed, 524 insertions, 33 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 41d5f1f92d5..52c7557f3e2 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -62,10 +62,51 @@ static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 static LIST_HEAD(o2hb_node_events);
 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
 
+/*
+ * In global heartbeat, we maintain a series of region bitmaps.
+ * 	- o2hb_region_bitmap allows us to limit the region number to max region.
+ * 	- o2hb_live_region_bitmap tracks live regions (seen steady iterations).
+ * 	- o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
+ * 		heartbeat on it.
+ * 	- o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
+ */
+static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+
+#define O2HB_DB_TYPE_LIVENODES		0
+#define O2HB_DB_TYPE_LIVEREGIONS	1
+#define O2HB_DB_TYPE_QUORUMREGIONS	2
+#define O2HB_DB_TYPE_FAILEDREGIONS	3
+#define O2HB_DB_TYPE_REGION_LIVENODES	4
+#define O2HB_DB_TYPE_REGION_NUMBER	5
+#define O2HB_DB_TYPE_REGION_ELAPSED_TIME	6
+struct o2hb_debug_buf {
+	int db_type;
+	int db_size;
+	int db_len;
+	void *db_data;
+};
+
+static struct o2hb_debug_buf *o2hb_db_livenodes;
+static struct o2hb_debug_buf *o2hb_db_liveregions;
+static struct o2hb_debug_buf *o2hb_db_quorumregions;
+static struct o2hb_debug_buf *o2hb_db_failedregions;
+
 #define O2HB_DEBUG_DIR			"o2hb"
 #define O2HB_DEBUG_LIVENODES		"livenodes"
+#define O2HB_DEBUG_LIVEREGIONS		"live_regions"
+#define O2HB_DEBUG_QUORUMREGIONS	"quorum_regions"
+#define O2HB_DEBUG_FAILEDREGIONS	"failed_regions"
+#define O2HB_DEBUG_REGION_NUMBER	"num"
+#define O2HB_DEBUG_REGION_ELAPSED_TIME	"elapsed_time_in_ms"
+
 static struct dentry *o2hb_debug_dir;
 static struct dentry *o2hb_debug_livenodes;
+static struct dentry *o2hb_debug_liveregions;
+static struct dentry *o2hb_debug_quorumregions;
+static struct dentry *o2hb_debug_failedregions;
 
 static LIST_HEAD(o2hb_all_regions);
 
@@ -77,7 +118,19 @@ static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 
 #define O2HB_DEFAULT_BLOCK_BITS       9
 
+enum o2hb_heartbeat_modes {
+	O2HB_HEARTBEAT_LOCAL		= 0,
+	O2HB_HEARTBEAT_GLOBAL,
+	O2HB_HEARTBEAT_NUM_MODES,
+};
+
+char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
+		"local",	/* O2HB_HEARTBEAT_LOCAL */
+		"global",	/* O2HB_HEARTBEAT_GLOBAL */
+};
+
 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
+unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 
 /* Only sets a new threshold if there are no active regions.
  *
@@ -94,6 +147,22 @@ static void o2hb_dead_threshold_set(unsigned int threshold)
 	}
 }
 
+static int o2hb_global_hearbeat_mode_set(unsigned int hb_mode)
+{
+	int ret = -1;
+
+	if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
+		spin_lock(&o2hb_live_lock);
+		if (list_empty(&o2hb_all_regions)) {
+			o2hb_heartbeat_mode = hb_mode;
+			ret = 0;
+		}
+		spin_unlock(&o2hb_live_lock);
+	}
+
+	return ret;
+}
+
 struct o2hb_node_event {
 	struct list_head        hn_item;
 	enum o2hb_callback_type hn_event_type;
@@ -135,6 +204,18 @@ struct o2hb_region {
 	struct block_device	*hr_bdev;
 	struct o2hb_disk_slot	*hr_slots;
 
+	/* live node map of this region */
+	unsigned long		hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
+	unsigned int		hr_region_num;
+
+	struct dentry		*hr_debug_dir;
+	struct dentry		*hr_debug_livenodes;
+	struct dentry		*hr_debug_regnum;
+	struct dentry		*hr_debug_elapsed_time;
+	struct o2hb_debug_buf	*hr_db_livenodes;
+	struct o2hb_debug_buf	*hr_db_regnum;
+	struct o2hb_debug_buf	*hr_db_elapsed_time;
+
 	/* let the person setting up hb wait for it to return until it
 	 * has reached a 'steady' state.  This will be fixed when we have
 	 * a more complete api that doesn't lead to this sort of fragility. */
@@ -163,8 +244,19 @@ struct o2hb_bio_wait_ctxt {
 	int               wc_error;
 };
 
+static int o2hb_pop_count(void *map, int count)
+{
+	int i = -1, pop = 0;
+
+	while ((i = find_next_bit(map, count, i + 1)) < count)
+		pop++;
+	return pop;
+}
+
 static void o2hb_write_timeout(struct work_struct *work)
 {
+	int failed, quorum;
+	unsigned long flags;
 	struct o2hb_region *reg =
 		container_of(work, struct o2hb_region,
 			     hr_write_timeout_work.work);
@@ -172,6 +264,28 @@ static void o2hb_write_timeout(struct work_struct *work)
 	mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 	     "milliseconds\n", reg->hr_dev_name,
 	     jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
+
+	if (o2hb_global_heartbeat_active()) {
+		spin_lock_irqsave(&o2hb_live_lock, flags);
+		if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
+			set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
+		failed = o2hb_pop_count(&o2hb_failed_region_bitmap,
+					O2NM_MAX_REGIONS);
+		quorum = o2hb_pop_count(&o2hb_quorum_region_bitmap,
+					O2NM_MAX_REGIONS);
+		spin_unlock_irqrestore(&o2hb_live_lock, flags);
+
+		mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
+		     quorum, failed);
+
+		/*
+		 * Fence if the number of failed regions >= half the number
+		 * of  quorum regions
+		 */
+		if ((failed << 1) < quorum)
+			return;
+	}
+
 	o2quo_disk_timeout();
 }
 
@@ -180,6 +294,11 @@ static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 	mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 	     O2HB_MAX_WRITE_TIMEOUT_MS);
 
+	if (o2hb_global_heartbeat_active()) {
+		spin_lock(&o2hb_live_lock);
+		clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
+		spin_unlock(&o2hb_live_lock);
+	}
 	cancel_delayed_work(&reg->hr_write_timeout_work);
 	reg->hr_last_timeout_start = jiffies;
 	schedule_delayed_work(&reg->hr_write_timeout_work,
@@ -513,6 +632,8 @@ static void o2hb_queue_node_event(struct o2hb_node_event *event,
 {
 	assert_spin_locked(&o2hb_live_lock);
 
+	BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
+
 	event->hn_event_type = type;
 	event->hn_node = node;
 	event->hn_node_num = node_num;
@@ -554,6 +675,35 @@ static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 	o2nm_node_put(node);
 }
 
+static void o2hb_set_quorum_device(struct o2hb_region *reg,
+				   struct o2hb_disk_slot *slot)
+{
+	assert_spin_locked(&o2hb_live_lock);
+
+	if (!o2hb_global_heartbeat_active())
+		return;
+
+	if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
+		return;
+
+	/*
+	 * A region can be added to the quorum only when it sees all
+	 * live nodes heartbeat on it. In other words, the region has been
+	 * added to all nodes.
+	 */
+	if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
+		   sizeof(o2hb_live_node_bitmap)))
+		return;
+
+	if (slot->ds_changed_samples < O2HB_LIVE_THRESHOLD)
+		return;
+
+	printk(KERN_NOTICE "o2hb: Region %s is now a quorum device\n",
+	       config_item_name(&reg->hr_item));
+
+	set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
+}
+
 static int o2hb_check_slot(struct o2hb_region *reg,
 			   struct o2hb_disk_slot *slot)
 {
@@ -565,14 +715,22 @@ static int o2hb_check_slot(struct o2hb_region *reg,
 	u64 cputime;
 	unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 	unsigned int slot_dead_ms;
+	int tmp;
 
 	memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 
-	/* Is this correct? Do we assume that the node doesn't exist
-	 * if we're not configured for him? */
+	/*
+	 * If a node is no longer configured but is still in the livemap, we
+	 * may need to clear that bit from the livemap.
+	 */
 	node = o2nm_get_node_by_num(slot->ds_node_num);
-	if (!node)
-		return 0;
+	if (!node) {
+		spin_lock(&o2hb_live_lock);
+		tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
+		spin_unlock(&o2hb_live_lock);
+		if (!tmp)
+			return 0;
+	}
 
 	if (!o2hb_verify_crc(reg, hb_block)) {
 		/* all paths from here will drop o2hb_live_lock for
@@ -639,8 +797,12 @@ fire_callbacks:
 		mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 		     slot->ds_node_num, (long long)slot->ds_last_generation);
 
+		set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
+
 		/* first on the list generates a callback */
 		if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
+			mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
+			     "bitmap\n", slot->ds_node_num);
 			set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 
 			o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
@@ -684,13 +846,18 @@ fire_callbacks:
 		mlog(ML_HEARTBEAT, "Node %d left my region\n",
 		     slot->ds_node_num);
 
+		clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
+
 		/* last off the live_slot generates a callback */
 		list_del_init(&slot->ds_live_item);
 		if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
+			mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
+			     "nodes bitmap\n", slot->ds_node_num);
 			clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 
-			o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
-					      slot->ds_node_num);
+			/* node can be null */
+			o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
+					      node, slot->ds_node_num);
 
 			changed = 1;
 		}
@@ -706,11 +873,14 @@ fire_callbacks:
 		slot->ds_equal_samples = 0;
 	}
 out:
+	o2hb_set_quorum_device(reg, slot);
+
 	spin_unlock(&o2hb_live_lock);
 
 	o2hb_run_event_list(&event);
 
-	o2nm_node_put(node);
+	if (node)
+		o2nm_node_put(node);
 	return changed;
 }
 
@@ -737,6 +907,7 @@ static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 {
 	int i, ret, highest_node, change = 0;
 	unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
+	unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 	struct o2hb_bio_wait_ctxt write_wc;
 
 	ret = o2nm_configured_node_map(configured_nodes,
@@ -746,6 +917,17 @@ static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 		return ret;
 	}
 
+	/*
+	 * If a node is not configured but is in the livemap, we still need
+	 * to read the slot so as to be able to remove it from the livemap.
+	 */
+	o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
+	i = -1;
+	while ((i = find_next_bit(live_node_bitmap,
+				  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
+		set_bit(i, configured_nodes);
+	}
+
 	highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
 	if (highest_node >= O2NM_MAX_NODES) {
 		mlog(ML_NOTICE, "ocfs2_heartbeat: no configured nodes found!\n");
@@ -917,21 +1099,59 @@ static int o2hb_thread(void *data)
 #ifdef CONFIG_DEBUG_FS
 static int o2hb_debug_open(struct inode *inode, struct file *file)
 {
+	struct o2hb_debug_buf *db = inode->i_private;
+	struct o2hb_region *reg;
 	unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 	char *buf = NULL;
 	int i = -1;
 	int out = 0;
 
+	/* max_nodes should be the largest bitmap we pass here */
+	BUG_ON(sizeof(map) < db->db_size);
+
 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buf)
 		goto bail;
 
-	o2hb_fill_node_map(map, sizeof(map));
+	switch (db->db_type) {
+	case O2HB_DB_TYPE_LIVENODES:
+	case O2HB_DB_TYPE_LIVEREGIONS:
+	case O2HB_DB_TYPE_QUORUMREGIONS:
+	case O2HB_DB_TYPE_FAILEDREGIONS:
+		spin_lock(&o2hb_live_lock);
+		memcpy(map, db->db_data, db->db_size);
+		spin_unlock(&o2hb_live_lock);
+		break;
+
+	case O2HB_DB_TYPE_REGION_LIVENODES:
+		spin_lock(&o2hb_live_lock);
+		reg = (struct o2hb_region *)db->db_data;
+		memcpy(map, reg->hr_live_node_bitmap, db->db_size);
+		spin_unlock(&o2hb_live_lock);
+		break;
+
+	case O2HB_DB_TYPE_REGION_NUMBER:
+		reg = (struct o2hb_region *)db->db_data;
+		out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
+				reg->hr_region_num);
+		goto done;
+
+	case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
+		reg = (struct o2hb_region *)db->db_data;
+		out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
+				jiffies_to_msecs(jiffies -
+						 reg->hr_last_timeout_start));
+		goto done;
+
+	default:
+		goto done;
+	}
 
-	while ((i = find_next_bit(map, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES)
+	while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
 		out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
 	out += snprintf(buf + out, PAGE_SIZE - out, "\n");
 
+done:
 	i_size_write(inode, out);
 
 	file->private_data = buf;
@@ -978,10 +1198,104 @@ static const struct file_operations o2hb_debug_fops = {
 
 void o2hb_exit(void)
 {
-	if (o2hb_debug_livenodes)
-		debugfs_remove(o2hb_debug_livenodes);
-	if (o2hb_debug_dir)
-		debugfs_remove(o2hb_debug_dir);
+	kfree(o2hb_db_livenodes);
+	kfree(o2hb_db_liveregions);
+	kfree(o2hb_db_quorumregions);
+	kfree(o2hb_db_failedregions);
+	debugfs_remove(o2hb_debug_failedregions);
+	debugfs_remove(o2hb_debug_quorumregions);
+	debugfs_remove(o2hb_debug_liveregions);
+	debugfs_remove(o2hb_debug_livenodes);
+	debugfs_remove(o2hb_debug_dir);
+}
+
+static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
+					struct o2hb_debug_buf **db, int db_len,
+					int type, int size, int len, void *data)
+{
+	*db = kmalloc(db_len, GFP_KERNEL);
+	if (!*db)
+		return NULL;
+
+	(*db)->db_type = type;
+	(*db)->db_size = size;
+	(*db)->db_len = len;
+	(*db)->db_data = data;
+
+	return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
+				   &o2hb_debug_fops);
+}
+
+static int o2hb_debug_init(void)
+{
+	int ret = -ENOMEM;
+
+	o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
+	if (!o2hb_debug_dir) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
+						 o2hb_debug_dir,
+						 &o2hb_db_livenodes,
+						 sizeof(*o2hb_db_livenodes),
+						 O2HB_DB_TYPE_LIVENODES,
+						 sizeof(o2hb_live_node_bitmap),
+						 O2NM_MAX_NODES,
+						 o2hb_live_node_bitmap);
+	if (!o2hb_debug_livenodes) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
+						   o2hb_debug_dir,
+						   &o2hb_db_liveregions,
+						   sizeof(*o2hb_db_liveregions),
+						   O2HB_DB_TYPE_LIVEREGIONS,
+						   sizeof(o2hb_live_region_bitmap),
+						   O2NM_MAX_REGIONS,
+						   o2hb_live_region_bitmap);
+	if (!o2hb_debug_liveregions) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	o2hb_debug_quorumregions =
+			o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
+					  o2hb_debug_dir,
+					  &o2hb_db_quorumregions,
+					  sizeof(*o2hb_db_quorumregions),
+					  O2HB_DB_TYPE_QUORUMREGIONS,
+					  sizeof(o2hb_quorum_region_bitmap),
+					  O2NM_MAX_REGIONS,
+					  o2hb_quorum_region_bitmap);
+	if (!o2hb_debug_quorumregions) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	o2hb_debug_failedregions =
+			o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
+					  o2hb_debug_dir,
+					  &o2hb_db_failedregions,
+					  sizeof(*o2hb_db_failedregions),
+					  O2HB_DB_TYPE_FAILEDREGIONS,
+					  sizeof(o2hb_failed_region_bitmap),
+					  O2NM_MAX_REGIONS,
+					  o2hb_failed_region_bitmap);
+	if (!o2hb_debug_failedregions) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	ret = 0;
+bail:
+	if (ret)
+		o2hb_exit();
+
+	return ret;
 }
 
 int o2hb_init(void)
@@ -997,24 +1311,12 @@ int o2hb_init(void)
 	INIT_LIST_HEAD(&o2hb_node_events);
 
 	memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
+	memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
+	memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
+	memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
+	memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
 
-	o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
-	if (!o2hb_debug_dir) {
-		mlog_errno(-ENOMEM);
-		return -ENOMEM;
-	}
-
-	o2hb_debug_livenodes = debugfs_create_file(O2HB_DEBUG_LIVENODES,
-						   S_IFREG|S_IRUSR,
-						   o2hb_debug_dir, NULL,
-						   &o2hb_debug_fops);
-	if (!o2hb_debug_livenodes) {
-		mlog_errno(-ENOMEM);
-		debugfs_remove(o2hb_debug_dir);
-		return -ENOMEM;
-	}
-
-	return 0;
+	return o2hb_debug_init();
 }
 
 /* if we're already in a callback then we're already serialized by the sem */
@@ -1078,6 +1380,13 @@ static void o2hb_region_release(struct config_item *item)
 	if (reg->hr_slots)
 		kfree(reg->hr_slots);
 
+	kfree(reg->hr_db_regnum);
+	kfree(reg->hr_db_livenodes);
+	debugfs_remove(reg->hr_debug_livenodes);
+	debugfs_remove(reg->hr_debug_regnum);
+	debugfs_remove(reg->hr_debug_elapsed_time);
+	debugfs_remove(reg->hr_debug_dir);
+
 	spin_lock(&o2hb_live_lock);
 	list_del(&reg->hr_all_item);
 	spin_unlock(&o2hb_live_lock);
@@ -1441,6 +1750,8 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
 	/* Ok, we were woken.  Make sure it wasn't by drop_item() */
 	spin_lock(&o2hb_live_lock);
 	hb_task = reg->hr_task;
+	if (o2hb_global_heartbeat_active())
+		set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
 	spin_unlock(&o2hb_live_lock);
 
 	if (hb_task)
@@ -1448,6 +1759,10 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
 	else
 		ret = -EIO;
 
+	if (hb_task && o2hb_global_heartbeat_active())
+		printk(KERN_NOTICE "o2hb: Heartbeat started on region %s\n",
+		       config_item_name(&reg->hr_item));
+
 out:
 	if (filp)
 		fput(filp);
@@ -1586,21 +1901,94 @@ static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group
 		: NULL;
 }
 
+static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
+{
+	int ret = -ENOMEM;
+
+	reg->hr_debug_dir =
+		debugfs_create_dir(config_item_name(&reg->hr_item), dir);
+	if (!reg->hr_debug_dir) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	reg->hr_debug_livenodes =
+			o2hb_debug_create(O2HB_DEBUG_LIVENODES,
+					  reg->hr_debug_dir,
+					  &(reg->hr_db_livenodes),
+					  sizeof(*(reg->hr_db_livenodes)),
+					  O2HB_DB_TYPE_REGION_LIVENODES,
+					  sizeof(reg->hr_live_node_bitmap),
+					  O2NM_MAX_NODES, reg);
+	if (!reg->hr_debug_livenodes) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	reg->hr_debug_regnum =
+			o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
+					  reg->hr_debug_dir,
+					  &(reg->hr_db_regnum),
+					  sizeof(*(reg->hr_db_regnum)),
+					  O2HB_DB_TYPE_REGION_NUMBER,
+					  0, O2NM_MAX_NODES, reg);
+	if (!reg->hr_debug_regnum) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	reg->hr_debug_elapsed_time =
+			o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
+					  reg->hr_debug_dir,
+					  &(reg->hr_db_elapsed_time),
+					  sizeof(*(reg->hr_db_elapsed_time)),
+					  O2HB_DB_TYPE_REGION_ELAPSED_TIME,
+					  0, 0, reg);
+	if (!reg->hr_debug_elapsed_time) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
+	ret = 0;
+bail:
+	return ret;
+}
+
 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
 							  const char *name)
 {
 	struct o2hb_region *reg = NULL;
+	int ret;
 
 	reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
 	if (reg == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
+	if (strlen(name) > O2HB_MAX_REGION_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
 
 	spin_lock(&o2hb_live_lock);
+	reg->hr_region_num = 0;
+	if (o2hb_global_heartbeat_active()) {
+		reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
+							 O2NM_MAX_REGIONS);
+		if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
+			spin_unlock(&o2hb_live_lock);
+			return ERR_PTR(-EFBIG);
+		}
+		set_bit(reg->hr_region_num, o2hb_region_bitmap);
+	}
 	list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
 	spin_unlock(&o2hb_live_lock);
 
+	config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
+
+	ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
+	if (ret) {
+		config_item_put(&reg->hr_item);
+		return ERR_PTR(ret);
+	}
+
 	return &reg->hr_item;
 }
 
@@ -1612,6 +2000,10 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group,
 
 	/* stop the thread when the user removes the region dir */
 	spin_lock(&o2hb_live_lock);
+	if (o2hb_global_heartbeat_active()) {
+		clear_bit(reg->hr_region_num, o2hb_region_bitmap);
+		clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
+	}
 	hb_task = reg->hr_task;
 	reg->hr_task = NULL;
 	spin_unlock(&o2hb_live_lock);
@@ -1628,6 +2020,9 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group,
 		wake_up(&o2hb_steady_queue);
 	}
 
+	if (o2hb_global_heartbeat_active())
+		printk(KERN_NOTICE "o2hb: Heartbeat stopped on region %s\n",
+		       config_item_name(&reg->hr_item));
 	config_item_put(item);
 }
 
@@ -1688,6 +2083,41 @@ static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group
 	return count;
 }
 
+static
+ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
+				       char *page)
+{
+	return sprintf(page, "%s\n",
+		       o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
+}
+
+static
+ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
+					const char *page, size_t count)
+{
+	unsigned int i;
+	int ret;
+	size_t len;
+
+	len = (page[count - 1] == '\n') ? count - 1 : count;
+	if (!len)
+		return -EINVAL;
+
+	for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
+		if (strnicmp(page, o2hb_heartbeat_mode_desc[i], len))
+			continue;
+
+		ret = o2hb_global_hearbeat_mode_set(i);
+		if (!ret)
+			printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
+			       o2hb_heartbeat_mode_desc[i]);
+		return count;
+	}
+
+	return -EINVAL;
+
+}
+
 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
 	.attr	= { .ca_owner = THIS_MODULE,
 		    .ca_name = "dead_threshold",
@@ -1696,8 +2126,17 @@ static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold
 	.store	= o2hb_heartbeat_group_threshold_store,
 };
 
+static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
+	.attr   = { .ca_owner = THIS_MODULE,
+		.ca_name = "mode",
+		.ca_mode = S_IRUGO | S_IWUSR },
+	.show   = o2hb_heartbeat_group_mode_show,
+	.store  = o2hb_heartbeat_group_mode_store,
+};
+
 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
 	&o2hb_heartbeat_group_attr_threshold.attr,
+	&o2hb_heartbeat_group_attr_mode.attr,
 	NULL,
 };
 
@@ -1963,3 +2402,34 @@ void o2hb_stop_all_regions(void)
 	spin_unlock(&o2hb_live_lock);
 }
 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
+
+int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
+{
+	struct o2hb_region *reg;
+	int numregs = 0;
+	char *p;
+
+	spin_lock(&o2hb_live_lock);
+
+	p = region_uuids;
+	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+		mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
+		if (numregs < max_regions) {
+			memcpy(p, config_item_name(&reg->hr_item),
+			       O2HB_MAX_REGION_NAME_LEN);
+			p += O2HB_MAX_REGION_NAME_LEN;
+		}
+		numregs++;
+	}
+
+	spin_unlock(&o2hb_live_lock);
+
+	return numregs;
+}
+EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
+
+int o2hb_global_heartbeat_active(void)
+{
+	return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
+}
+EXPORT_SYMBOL(o2hb_global_heartbeat_active);
diff --git a/fs/ocfs2/cluster/heartbeat.h b/fs/ocfs2/cluster/heartbeat.h
index 2f1649253b4..00ad8e8fea5 100644
--- a/fs/ocfs2/cluster/heartbeat.h
+++ b/fs/ocfs2/cluster/heartbeat.h
@@ -31,6 +31,8 @@
 
 #define O2HB_REGION_TIMEOUT_MS		2000
 
+#define O2HB_MAX_REGION_NAME_LEN	32
+
 /* number of changes to be seen as live */
 #define O2HB_LIVE_THRESHOLD	   2
 /* number of equal samples to be seen as dead */
@@ -81,5 +83,7 @@ int o2hb_check_node_heartbeating(u8 node_num);
 int o2hb_check_node_heartbeating_from_callback(u8 node_num);
 int o2hb_check_local_node_heartbeating(void);
 void o2hb_stop_all_regions(void);
+int o2hb_get_all_regions(char *region_uuids, u8 numregions);
+int o2hb_global_heartbeat_active(void);
 
 #endif /* O2CLUSTER_HEARTBEAT_H */
diff --git a/fs/ocfs2/cluster/masklog.h b/fs/ocfs2/cluster/masklog.h
index fd96e2a2fa5..ea2ed9f56c9 100644
--- a/fs/ocfs2/cluster/masklog.h
+++ b/fs/ocfs2/cluster/masklog.h
@@ -119,7 +119,8 @@
 #define ML_ERROR	0x0000000100000000ULL /* sent to KERN_ERR */
 #define ML_NOTICE	0x0000000200000000ULL /* setn to KERN_NOTICE */
 #define ML_KTHREAD	0x0000000400000000ULL /* kernel thread activity */
-#define	ML_RESERVATIONS	0x0000000800000000ULL /* ocfs2 alloc reservations */
+#define ML_RESERVATIONS	0x0000000800000000ULL /* ocfs2 alloc reservations */
+#define ML_CLUSTER	0x0000001000000000ULL /* cluster stack */
 
 #define MLOG_INITIAL_AND_MASK (ML_ERROR|ML_NOTICE)
 #define MLOG_INITIAL_NOT_MASK (ML_ENTRY|ML_EXIT)
diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c
index ed0c9f367fe..bb240647ca5 100644
--- a/fs/ocfs2/cluster/nodemanager.c
+++ b/fs/ocfs2/cluster/nodemanager.c
@@ -711,6 +711,8 @@ static struct config_item *o2nm_node_group_make_item(struct config_group *group,
 	config_item_init_type_name(&node->nd_item, name, &o2nm_node_type);
 	spin_lock_init(&node->nd_lock);
 
+	mlog(ML_CLUSTER, "o2nm: Registering node %s\n", name);
+
 	return &node->nd_item;
 }
 
@@ -744,6 +746,9 @@ static void o2nm_node_group_drop_item(struct config_group *group,
 	}
 	write_unlock(&cluster->cl_nodes_lock);
 
+	mlog(ML_CLUSTER, "o2nm: Unregistered node %s\n",
+	     config_item_name(&node->nd_item));
+
 	config_item_put(item);
 }
 
diff --git a/fs/ocfs2/cluster/ocfs2_nodemanager.h b/fs/ocfs2/cluster/ocfs2_nodemanager.h
index 5b9854bad57..49b594325be 100644
--- a/fs/ocfs2/cluster/ocfs2_nodemanager.h
+++ b/fs/ocfs2/cluster/ocfs2_nodemanager.h
@@ -36,4 +36,10 @@
 /* host name, group name, cluster name all 64 bytes */
 #define O2NM_MAX_NAME_LEN        64    // __NEW_UTS_LEN
 
+/*
+ * Maximum number of global heartbeat regions allowed.
+ * **CAUTION**  Changing this number will break dlm compatibility.
+ */
+#define O2NM_MAX_REGIONS	32
+
 #endif /* _OCFS2_NODEMANAGER_H */
diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index cbe2f057cc2..9aa426e4212 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -1696,6 +1696,9 @@ static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
 {
 	o2quo_hb_down(node_num);
 
+	if (!node)
+		return;
+
 	if (node_num != o2nm_this_node())
 		o2net_disconnect_node(node);
 
@@ -1709,6 +1712,8 @@ static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
 
 	o2quo_hb_up(node_num);
 
+	BUG_ON(!node);
+
 	/* ensure an immediate connect attempt */
 	nn->nn_last_connect_attempt = jiffies -
 		(msecs_to_jiffies(o2net_reconnect_delay()) + 1);
diff --git a/fs/ocfs2/cluster/tcp_internal.h b/fs/ocfs2/cluster/tcp_internal.h
index 96fa7ebc530..15fdbdf9eb4 100644
--- a/fs/ocfs2/cluster/tcp_internal.h
+++ b/fs/ocfs2/cluster/tcp_internal.h
@@ -129,7 +129,7 @@ struct o2net_node {
 
 struct o2net_sock_container {
 	struct kref		sc_kref;
-	/* the next two are vaild for the life time of the sc */
+	/* the next two are valid for the life time of the sc */
 	struct socket		*sc_sock;
 	struct o2nm_node	*sc_node;