heartbeat.c

linux 内核源代码

		    .ca_name = "blocks",
		    .ca_mode = S_IRUGO | S_IWUSR },
	.show	= o2hb_region_blocks_read,
	.store	= o2hb_region_blocks_write,
};

static struct o2hb_region_attribute o2hb_region_attr_dev = {
	.attr	= { .ca_owner = THIS_MODULE,
		    .ca_name = "dev",
		    .ca_mode = S_IRUGO | S_IWUSR },
	.show	= o2hb_region_dev_read,
	.store	= o2hb_region_dev_write,
};

static struct o2hb_region_attribute o2hb_region_attr_pid = {
       .attr   = { .ca_owner = THIS_MODULE,
                   .ca_name = "pid",
                   .ca_mode = S_IRUGO | S_IRUSR },
       .show   = o2hb_region_pid_read,
};

static struct configfs_attribute *o2hb_region_attrs[] = {
	&o2hb_region_attr_block_bytes.attr,
	&o2hb_region_attr_start_block.attr,
	&o2hb_region_attr_blocks.attr,
	&o2hb_region_attr_dev.attr,
	&o2hb_region_attr_pid.attr,
	NULL,
};

static ssize_t o2hb_region_show(struct config_item *item,
				struct configfs_attribute *attr,
				char *page)
{
	struct o2hb_region *reg = to_o2hb_region(item);
	struct o2hb_region_attribute *o2hb_region_attr =
		container_of(attr, struct o2hb_region_attribute, attr);
	ssize_t ret = 0;

	if (o2hb_region_attr->show)
		ret = o2hb_region_attr->show(reg, page);
	return ret;
}

static ssize_t o2hb_region_store(struct config_item *item,
				 struct configfs_attribute *attr,
				 const char *page, size_t count)
{
	struct o2hb_region *reg = to_o2hb_region(item);
	struct o2hb_region_attribute *o2hb_region_attr =
		container_of(attr, struct o2hb_region_attribute, attr);
	ssize_t ret = -EINVAL;

	if (o2hb_region_attr->store)
		ret = o2hb_region_attr->store(reg, page, count);
	return ret;
}

static struct configfs_item_operations o2hb_region_item_ops = {
	.release		= o2hb_region_release,
	.show_attribute		= o2hb_region_show,
	.store_attribute	= o2hb_region_store,
};

static struct config_item_type o2hb_region_type = {
	.ct_item_ops	= &o2hb_region_item_ops,
	.ct_attrs	= o2hb_region_attrs,
	.ct_owner	= THIS_MODULE,
};

/* heartbeat set */

struct o2hb_heartbeat_group {
	struct config_group hs_group;
	/* some stuff? */
};

static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
{
	return group ?
		container_of(group, struct o2hb_heartbeat_group, hs_group)
		: NULL;
}

static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
							  const char *name)
{
	struct o2hb_region *reg = NULL;
	struct config_item *ret = NULL;

	reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
	if (reg == NULL)
		goto out; /* ENOMEM */

	config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);

	ret = &reg->hr_item;

	spin_lock(&o2hb_live_lock);
	list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
	spin_unlock(&o2hb_live_lock);
out:
	if (ret == NULL)
		kfree(reg);

	return ret;
}

static void o2hb_heartbeat_group_drop_item(struct config_group *group,
					   struct config_item *item)
{
	struct task_struct *hb_task;
	struct o2hb_region *reg = to_o2hb_region(item);

	/* stop the thread when the user removes the region dir */
	spin_lock(&o2hb_live_lock);
	hb_task = reg->hr_task;
	reg->hr_task = NULL;
	spin_unlock(&o2hb_live_lock);

	if (hb_task)
		kthread_stop(hb_task);

	/*
	 * If we're racing a dev_write(), we need to wake them.  They will
	 * check reg->hr_task
	 */
	if (atomic_read(&reg->hr_steady_iterations) != 0) {
		atomic_set(&reg->hr_steady_iterations, 0);
		wake_up(&o2hb_steady_queue);
	}

	config_item_put(item);
}

struct o2hb_heartbeat_group_attribute {
	struct configfs_attribute attr;
	ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
	ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
};

static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
					 struct configfs_attribute *attr,
					 char *page)
{
	struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
	struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
		container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
	ssize_t ret = 0;

	if (o2hb_heartbeat_group_attr->show)
		ret = o2hb_heartbeat_group_attr->show(reg, page);
	return ret;
}

static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
					  struct configfs_attribute *attr,
					  const char *page, size_t count)
{
	struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
	struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
		container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
	ssize_t ret = -EINVAL;

	if (o2hb_heartbeat_group_attr->store)
		ret = o2hb_heartbeat_group_attr->store(reg, page, count);
	return ret;
}

static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
						     char *page)
{
	return sprintf(page, "%u\n", o2hb_dead_threshold);
}

static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
						    const char *page,
						    size_t count)
{
	unsigned long tmp;
	char *p = (char *)page;

	tmp = simple_strtoul(p, &p, 10);
	if (!p || (*p && (*p != '\n')))
                return -EINVAL;

	/* this will validate ranges for us. */
	o2hb_dead_threshold_set((unsigned int) tmp);

	return count;
}

static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
	.attr	= { .ca_owner = THIS_MODULE,
		    .ca_name = "dead_threshold",
		    .ca_mode = S_IRUGO | S_IWUSR },
	.show	= o2hb_heartbeat_group_threshold_show,
	.store	= o2hb_heartbeat_group_threshold_store,
};

static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
	&o2hb_heartbeat_group_attr_threshold.attr,
	NULL,
};

static struct configfs_item_operations o2hb_hearbeat_group_item_ops = {
	.show_attribute		= o2hb_heartbeat_group_show,
	.store_attribute	= o2hb_heartbeat_group_store,
};

static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
	.make_item	= o2hb_heartbeat_group_make_item,
	.drop_item	= o2hb_heartbeat_group_drop_item,
};

static struct config_item_type o2hb_heartbeat_group_type = {
	.ct_group_ops	= &o2hb_heartbeat_group_group_ops,
	.ct_item_ops	= &o2hb_hearbeat_group_item_ops,
	.ct_attrs	= o2hb_heartbeat_group_attrs,
	.ct_owner	= THIS_MODULE,
};

/* this is just here to avoid touching group in heartbeat.h which the
 * entire damn world #includes */
struct config_group *o2hb_alloc_hb_set(void)
{
	struct o2hb_heartbeat_group *hs = NULL;
	struct config_group *ret = NULL;

	hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
	if (hs == NULL)
		goto out;

	config_group_init_type_name(&hs->hs_group, "heartbeat",
				    &o2hb_heartbeat_group_type);

	ret = &hs->hs_group;
out:
	if (ret == NULL)
		kfree(hs);
	return ret;
}

void o2hb_free_hb_set(struct config_group *group)
{
	struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
	kfree(hs);
}

/* hb callback registration and issueing */

static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
{
	if (type == O2HB_NUM_CB)
		return ERR_PTR(-EINVAL);

	return &o2hb_callbacks[type];
}

void o2hb_setup_callback(struct o2hb_callback_func *hc,
			 enum o2hb_callback_type type,
			 o2hb_cb_func *func,
			 void *data,
			 int priority)
{
	INIT_LIST_HEAD(&hc->hc_item);
	hc->hc_func = func;
	hc->hc_data = data;
	hc->hc_priority = priority;
	hc->hc_type = type;
	hc->hc_magic = O2HB_CB_MAGIC;
}
EXPORT_SYMBOL_GPL(o2hb_setup_callback);

static struct o2hb_region *o2hb_find_region(const char *region_uuid)
{
	struct o2hb_region *p, *reg = NULL;

	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;
		}
	}

	return reg;
}

static int o2hb_region_get(const char *region_uuid)
{
	int ret = 0;
	struct o2hb_region *reg;

	spin_lock(&o2hb_live_lock);

	reg = o2hb_find_region(region_uuid);
	if (!reg)
		ret = -ENOENT;
	spin_unlock(&o2hb_live_lock);

	if (ret)
		goto out;

	ret = o2nm_depend_this_node();
	if (ret)
		goto out;

	ret = o2nm_depend_item(&reg->hr_item);
	if (ret)
		o2nm_undepend_this_node();

out:
	return ret;
}

static void o2hb_region_put(const char *region_uuid)
{
	struct o2hb_region *reg;

	spin_lock(&o2hb_live_lock);

	reg = o2hb_find_region(region_uuid);

	spin_unlock(&o2hb_live_lock);

	if (reg) {
		o2nm_undepend_item(&reg->hr_item);
		o2nm_undepend_this_node();
	}
}

int o2hb_register_callback(const char *region_uuid,
			   struct o2hb_callback_func *hc)
{
	struct o2hb_callback_func *tmp;
	struct list_head *iter;
	struct o2hb_callback *hbcall;
	int ret;

	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
	BUG_ON(!list_empty(&hc->hc_item));

	hbcall = hbcall_from_type(hc->hc_type);
	if (IS_ERR(hbcall)) {
		ret = PTR_ERR(hbcall);
		goto out;
	}

	if (region_uuid) {
		ret = o2hb_region_get(region_uuid);
		if (ret)
			goto out;
	}

	down_write(&o2hb_callback_sem);

	list_for_each(iter, &hbcall->list) {
		tmp = list_entry(iter, struct o2hb_callback_func, hc_item);
		if (hc->hc_priority < tmp->hc_priority) {
			list_add_tail(&hc->hc_item, iter);
			break;
		}
	}
	if (list_empty(&hc->hc_item))
		list_add_tail(&hc->hc_item, &hbcall->list);

	up_write(&o2hb_callback_sem);
	ret = 0;
out:
	mlog(ML_HEARTBEAT, "returning %d on behalf of %p for funcs %p\n",
	     ret, __builtin_return_address(0), hc);
	return ret;
}
EXPORT_SYMBOL_GPL(o2hb_register_callback);

void o2hb_unregister_callback(const char *region_uuid,
			      struct o2hb_callback_func *hc)
{
	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);

	mlog(ML_HEARTBEAT, "on behalf of %p for funcs %p\n",
	     __builtin_return_address(0), hc);

	/* XXX Can this happen _with_ a region reference? */
	if (list_empty(&hc->hc_item))
		return;

	if (region_uuid)
		o2hb_region_put(region_uuid);

	down_write(&o2hb_callback_sem);

	list_del_init(&hc->hc_item);

	up_write(&o2hb_callback_sem);
}
EXPORT_SYMBOL_GPL(o2hb_unregister_callback);

int o2hb_check_node_heartbeating(u8 node_num)
{
	unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];

	o2hb_fill_node_map(testing_map, sizeof(testing_map));
	if (!test_bit(node_num, testing_map)) {
		mlog(ML_HEARTBEAT,
		     "node (%u) does not have heartbeating enabled.\n",
		     node_num);
		return 0;
	}

	return 1;
}
EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);

int o2hb_check_node_heartbeating_from_callback(u8 node_num)
{
	unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];

	o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
	if (!test_bit(node_num, testing_map)) {
		mlog(ML_HEARTBEAT,
		     "node (%u) does not have heartbeating enabled.\n",
		     node_num);
		return 0;
	}

	return 1;
}
EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);

/* Makes sure our local node is configured with a node number, and is
 * heartbeating. */
int o2hb_check_local_node_heartbeating(void)
{
	u8 node_num;

	/* if this node was set then we have networking */
	node_num = o2nm_this_node();
	if (node_num == O2NM_MAX_NODES) {
		mlog(ML_HEARTBEAT, "this node has not been configured.\n");
		return 0;
	}

	return o2hb_check_node_heartbeating(node_num);
}
EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);

/*
 * this is just a hack until we get the plumbing which flips file systems
 * read only and drops the hb ref instead of killing the node dead.
 */
void o2hb_stop_all_regions(void)
{
	struct o2hb_region *reg;

	mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");

	spin_lock(&o2hb_live_lock);

	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
		reg->hr_unclean_stop = 1;

	spin_unlock(&o2hb_live_lock);
}
EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);