commit 536f0741f324f116d8b059295999945a2dac56bc
author Sunil Mushran <sunil.mushran@oracle.com> Thu Oct 07 17:03:07 2010 -0700
committer Sunil Mushran <sunil.mushran@oracle.com> Thu Oct 07 17:03:07 2010 -0700
tree 56eb9198d5241da7416f37473584c8e718ffd3b9
parent 823a637ae933fde8fdb280612dd3ff9912e301e3

ocfs2/cluster: Track number of global heartbeat regions

In global heartbeat mode, we have a upper limit for the number of active regions.
This patch adds the facility to track the number of active global heartbeat
regions and fails to start heartbeat if the number exceeds the maximum.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>

fs/ocfs2/cluster/heartbeat.c

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 188f502..d66b17c 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -62,6 +62,12 @@
 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.
+ */
+static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+
 #define O2HB_DB_TYPE_LIVENODES		0
 struct o2hb_debug_buf {
 	int db_type;
@@ -176,6 +182,7 @@
 
 	/* live node map of this region */
 	unsigned long		hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
+	unsigned int		hr_region_num;
 
 	/* 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
@@ -1127,6 +1134,7 @@
 	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));
 
 	return o2hb_debug_init();
 }
@@ -1716,12 +1724,22 @@
 	if (strlen(name) > O2HB_MAX_REGION_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
-	config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
-
 	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);
+
 	return &reg->hr_item;
 }
 
@@ -1733,6 +1751,8 @@
 
 	/* 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);
 	hb_task = reg->hr_task;
 	reg->hr_task = NULL;
 	spin_unlock(&o2hb_live_lock);