1 files changed, 208 insertions, 38 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 9e3d45bcb5f..a6cc05302e9 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -82,6 +82,7 @@ static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 #define O2HB_DB_TYPE_REGION_LIVENODES	4
 #define O2HB_DB_TYPE_REGION_NUMBER	5
 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME	6
+#define O2HB_DB_TYPE_REGION_PINNED	7
 struct o2hb_debug_buf {
 	int db_type;
 	int db_size;
@@ -101,6 +102,7 @@ static struct o2hb_debug_buf *o2hb_db_failedregions;
 #define O2HB_DEBUG_FAILEDREGIONS	"failed_regions"
 #define O2HB_DEBUG_REGION_NUMBER	"num"
 #define O2HB_DEBUG_REGION_ELAPSED_TIME	"elapsed_time_in_ms"
+#define O2HB_DEBUG_REGION_PINNED	"pinned"
 
 static struct dentry *o2hb_debug_dir;
 static struct dentry *o2hb_debug_livenodes;
@@ -132,6 +134,33 @@ char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 
+/*
+ * o2hb_dependent_users tracks the number of registered callbacks that depend
+ * on heartbeat. o2net and o2dlm are two entities that register this callback.
+ * However only o2dlm depends on the heartbeat. It does not want the heartbeat
+ * to stop while a dlm domain is still active.
+ */
+unsigned int o2hb_dependent_users;
+
+/*
+ * In global heartbeat mode, all regions are pinned if there are one or more
+ * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
+ * regions are unpinned if the region count exceeds the cut off or the number
+ * of dependent users falls to zero.
+ */
+#define O2HB_PIN_CUT_OFF		3
+
+/*
+ * In local heartbeat mode, we assume the dlm domain name to be the same as
+ * region uuid. This is true for domains created for the file system but not
+ * necessarily true for userdlm domains. This is a known limitation.
+ *
+ * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
+ * works for both file system and userdlm domains.
+ */
+static int o2hb_region_pin(const char *region_uuid);
+static void o2hb_region_unpin(const char *region_uuid);
+
 /* Only sets a new threshold if there are no active regions.
  *
  * No locking or otherwise interesting code is required for reading
@@ -186,7 +215,9 @@ struct o2hb_region {
 	struct config_item	hr_item;
 
 	struct list_head	hr_all_item;
-	unsigned		hr_unclean_stop:1;
+	unsigned		hr_unclean_stop:1,
+				hr_item_pinned:1,
+				hr_item_dropped:1;
 
 	/* protected by the hr_callback_sem */
 	struct task_struct 	*hr_task;
@@ -212,9 +243,11 @@ struct o2hb_region {
 	struct dentry		*hr_debug_livenodes;
 	struct dentry		*hr_debug_regnum;
 	struct dentry		*hr_debug_elapsed_time;
+	struct dentry		*hr_debug_pinned;
 	struct o2hb_debug_buf	*hr_db_livenodes;
 	struct o2hb_debug_buf	*hr_db_regnum;
 	struct o2hb_debug_buf	*hr_db_elapsed_time;
+	struct o2hb_debug_buf	*hr_db_pinned;
 
 	/* 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
@@ -701,6 +734,14 @@ static void o2hb_set_quorum_device(struct o2hb_region *reg,
 	       config_item_name(&reg->hr_item));
 
 	set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
+
+	/*
+	 * If global heartbeat active, unpin all regions if the
+	 * region count > CUT_OFF
+	 */
+	if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
+			   O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
+		o2hb_region_unpin(NULL);
 }
 
 static int o2hb_check_slot(struct o2hb_region *reg,
@@ -1041,6 +1082,9 @@ static int o2hb_thread(void *data)
 
 	set_user_nice(current, -20);
 
+	/* Pin node */
+	o2nm_depend_this_node();
+
 	while (!kthread_should_stop() && !reg->hr_unclean_stop) {
 		/* We track the time spent inside
 		 * o2hb_do_disk_heartbeat so that we avoid more than
@@ -1090,6 +1134,9 @@ static int o2hb_thread(void *data)
 		mlog_errno(ret);
 	}
 
+	/* Unpin node */
+	o2nm_undepend_this_node();
+
 	mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread exiting\n");
 
 	return 0;
@@ -1142,6 +1189,12 @@ static int o2hb_debug_open(struct inode *inode, struct file *file)
 						 reg->hr_last_timeout_start));
 		goto done;
 
+	case O2HB_DB_TYPE_REGION_PINNED:
+		reg = (struct o2hb_region *)db->db_data;
+		out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
+				!!reg->hr_item_pinned);
+		goto done;
+
 	default:
 		goto done;
 	}
@@ -1315,6 +1368,8 @@ int o2hb_init(void)
 	memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
 	memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
 
+	o2hb_dependent_users = 0;
+
 	return o2hb_debug_init();
 }
 
@@ -1384,6 +1439,7 @@ static void o2hb_region_release(struct config_item *item)
 	debugfs_remove(reg->hr_debug_livenodes);
 	debugfs_remove(reg->hr_debug_regnum);
 	debugfs_remove(reg->hr_debug_elapsed_time);
+	debugfs_remove(reg->hr_debug_pinned);
 	debugfs_remove(reg->hr_debug_dir);
 
 	spin_lock(&o2hb_live_lock);
@@ -1948,6 +2004,18 @@ static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
 		goto bail;
 	}
 
+	reg->hr_debug_pinned =
+			o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
+					  reg->hr_debug_dir,
+					  &(reg->hr_db_pinned),
+					  sizeof(*(reg->hr_db_pinned)),
+					  O2HB_DB_TYPE_REGION_PINNED,
+					  0, 0, reg);
+	if (!reg->hr_debug_pinned) {
+		mlog_errno(ret);
+		goto bail;
+	}
+
 	ret = 0;
 bail:
 	return ret;
@@ -2002,15 +2070,20 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group,
 {
 	struct task_struct *hb_task;
 	struct o2hb_region *reg = to_o2hb_region(item);
+	int quorum_region = 0;
 
 	/* 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);
+		if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
+			quorum_region = 1;
+		clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 	}
 	hb_task = reg->hr_task;
 	reg->hr_task = NULL;
+	reg->hr_item_dropped = 1;
 	spin_unlock(&o2hb_live_lock);
 
 	if (hb_task)
@@ -2028,7 +2101,27 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group,
 	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);
+
+	if (!o2hb_global_heartbeat_active() || !quorum_region)
+		return;
+
+	/*
+	 * If global heartbeat active and there are dependent users,
+	 * pin all regions if quorum region count <= CUT_OFF
+	 */
+	spin_lock(&o2hb_live_lock);
+
+	if (!o2hb_dependent_users)
+		goto unlock;
+
+	if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
+			   O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
+		o2hb_region_pin(NULL);
+
+unlock:
+	spin_unlock(&o2hb_live_lock);
 }
 
 struct o2hb_heartbeat_group_attribute {
@@ -2214,63 +2307,138 @@ void o2hb_setup_callback(struct o2hb_callback_func *hc,
 }
 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
 
-static struct o2hb_region *o2hb_find_region(const char *region_uuid)
+/*
+ * In local heartbeat mode, region_uuid passed matches the dlm domain name.
+ * In global heartbeat mode, region_uuid passed is NULL.
+ *
+ * In local, we only pin the matching region. In global we pin all the active
+ * regions.
+ */
+static int o2hb_region_pin(const char *region_uuid)
 {
-	struct o2hb_region *p, *reg = NULL;
+	int ret = 0, found = 0;
+	struct o2hb_region *reg;
+	char *uuid;
 
 	assert_spin_locked(&o2hb_live_lock);
 
-	list_for_each_entry(p, &o2hb_all_regions, hr_all_item) {
-		if (!strcmp(region_uuid, config_item_name(&p->hr_item))) {
-			reg = p;
-			break;
+	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+		uuid = config_item_name(&reg->hr_item);
+
+		/* local heartbeat */
+		if (region_uuid) {
+			if (strcmp(region_uuid, uuid))
+				continue;
+			found = 1;
+		}
+
+		if (reg->hr_item_pinned || reg->hr_item_dropped)
+			goto skip_pin;
+
+		/* Ignore ENOENT only for local hb (userdlm domain) */
+		ret = o2nm_depend_item(&reg->hr_item);
+		if (!ret) {
+			mlog(ML_CLUSTER, "Pin region %s\n", uuid);
+			reg->hr_item_pinned = 1;
+		} else {
+			if (ret == -ENOENT && found)
+				ret = 0;
+			else {
+				mlog(ML_ERROR, "Pin region %s fails with %d\n",
+				     uuid, ret);
+				break;
+			}
 		}
+skip_pin:
+		if (found)
+			break;
 	}
 
-	return reg;
+	return ret;
 }
 
-static int o2hb_region_get(const char *region_uuid)
+/*
+ * In local heartbeat mode, region_uuid passed matches the dlm domain name.
+ * In global heartbeat mode, region_uuid passed is NULL.
+ *
+ * In local, we only unpin the matching region. In global we unpin all the
+ * active regions.
+ */
+static void o2hb_region_unpin(const char *region_uuid)
 {
-	int ret = 0;
 	struct o2hb_region *reg;
+	char *uuid;
+	int found = 0;
 
-	spin_lock(&o2hb_live_lock);
+	assert_spin_locked(&o2hb_live_lock);
 
-	reg = o2hb_find_region(region_uuid);
-	if (!reg)
-		ret = -ENOENT;
-	spin_unlock(&o2hb_live_lock);
+	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+		uuid = config_item_name(&reg->hr_item);
+		if (region_uuid) {
+			if (strcmp(region_uuid, uuid))
+				continue;
+			found = 1;
+		}
 
-	if (ret)
-		goto out;
+		if (reg->hr_item_pinned) {
+			mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
+			o2nm_undepend_item(&reg->hr_item);
+			reg->hr_item_pinned = 0;
+		}
+		if (found)
+			break;
+	}
+}
 
-	ret = o2nm_depend_this_node();
-	if (ret)
-		goto out;
+static int o2hb_region_inc_user(const char *region_uuid)
+{
+	int ret = 0;
 
-	ret = o2nm_depend_item(&reg->hr_item);
-	if (ret)
-		o2nm_undepend_this_node();
+	spin_lock(&o2hb_live_lock);
 
-out:
+	/* local heartbeat */
+	if (!o2hb_global_heartbeat_active()) {
+	    ret = o2hb_region_pin(region_uuid);
+	    goto unlock;
+	}
+
+	/*
+	 * if global heartbeat active and this is the first dependent user,
+	 * pin all regions if quorum region count <= CUT_OFF
+	 */
+	o2hb_dependent_users++;
+	if (o2hb_dependent_users > 1)
+		goto unlock;
+
+	if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
+			   O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
+		ret = o2hb_region_pin(NULL);
+
+unlock:
+	spin_unlock(&o2hb_live_lock);
 	return ret;
 }
 
-static void o2hb_region_put(const char *region_uuid)
+void o2hb_region_dec_user(const char *region_uuid)
 {
-	struct o2hb_region *reg;
-
 	spin_lock(&o2hb_live_lock);
 
-	reg = o2hb_find_region(region_uuid);
+	/* local heartbeat */
+	if (!o2hb_global_heartbeat_active()) {
+	    o2hb_region_unpin(region_uuid);
+	    goto unlock;
+	}
 
-	spin_unlock(&o2hb_live_lock);
+	/*
+	 * if global heartbeat active and there are no dependent users,
+	 * unpin all quorum regions
+	 */
+	o2hb_dependent_users--;
+	if (!o2hb_dependent_users)
+		o2hb_region_unpin(NULL);
 
-	if (reg) {
-		o2nm_undepend_item(&reg->hr_item);
-		o2nm_undepend_this_node();
-	}
+unlock:
+	spin_unlock(&o2hb_live_lock);
 }
 
 int o2hb_register_callback(const char *region_uuid,
@@ -2291,9 +2459,11 @@ int o2hb_register_callback(const char *region_uuid,
 	}
 
 	if (region_uuid) {
-		ret = o2hb_region_get(region_uuid);
-		if (ret)
+		ret = o2hb_region_inc_user(region_uuid);
+		if (ret) {
+			mlog_errno(ret);
 			goto out;
+		}
 	}
 
 	down_write(&o2hb_callback_sem);
@@ -2311,7 +2481,7 @@ int o2hb_register_callback(const char *region_uuid,
 	up_write(&o2hb_callback_sem);
 	ret = 0;
 out:
-	mlog(ML_HEARTBEAT, "returning %d on behalf of %p for funcs %p\n",
+	mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
 	     ret, __builtin_return_address(0), hc);
 	return ret;
 }
@@ -2322,7 +2492,7 @@ void o2hb_unregister_callback(const char *region_uuid,
 {
 	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
 
-	mlog(ML_HEARTBEAT, "on behalf of %p for funcs %p\n",
+	mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
 	     __builtin_return_address(0), hc);
 
 	/* XXX Can this happen _with_ a region reference? */
@@ -2330,7 +2500,7 @@ void o2hb_unregister_callback(const char *region_uuid,
 		return;
 
 	if (region_uuid)
-		o2hb_region_put(region_uuid);
+		o2hb_region_dec_user(region_uuid);
 
 	down_write(&o2hb_callback_sem);