drbd: Backport the "events2" command

The events2 command originates from drbd-9 development. It features
more information but requires a incompatible change in output
format.
Therefore the previous events command continues to exist, the new
improved events2 command becomes available now.

This prepares the user-base for a later switch to the complete
drbd9 code base.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 622 insertions, 3 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index d37c509e6a44..aa805cdde769 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -36,6 +36,7 @@
 #include "drbd_int.h"
 #include "drbd_protocol.h"
 #include "drbd_req.h"
+#include "drbd_state_change.h"
 #include <asm/unaligned.h>
 #include <linux/drbd_limits.h>
 #include <linux/kthread.h>
@@ -75,11 +76,17 @@ int drbd_adm_get_status(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info);
 /* .dumpit */
 int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb);
+int drbd_adm_get_initial_state(struct sk_buff *skb, struct netlink_callback *cb);
 
 #include <linux/drbd_genl_api.h>
 #include "drbd_nla.h"
 #include <linux/genl_magic_func.h>
 
+static atomic_t drbd_genl_seq = ATOMIC_INIT(2); /* two. */
+static atomic_t notify_genl_seq = ATOMIC_INIT(2); /* two. */
+
+DEFINE_MUTEX(notification_mutex);
+
 /* used blkdev_get_by_path, to claim our meta data device(s) */
 static char *drbd_m_holder = "Hands off! this is DRBD's meta data device.";
 
@@ -349,6 +356,7 @@ int drbd_khelper(struct drbd_device *device, char *cmd)
 	sib.sib_reason = SIB_HELPER_PRE;
 	sib.helper_name = cmd;
 	drbd_bcast_event(device, &sib);
+	notify_helper(NOTIFY_CALL, device, connection, cmd, 0);
 	ret = call_usermodehelper(usermode_helper, argv, envp, UMH_WAIT_PROC);
 	if (ret)
 		drbd_warn(device, "helper command: %s %s %s exit code %u (0x%x)\n",
@@ -361,6 +369,7 @@ int drbd_khelper(struct drbd_device *device, char *cmd)
 	sib.sib_reason = SIB_HELPER_POST;
 	sib.helper_exit_code = ret;
 	drbd_bcast_event(device, &sib);
+	notify_helper(NOTIFY_RESPONSE, device, connection, cmd, ret);
 
 	if (current == connection->worker.task)
 		clear_bit(CALLBACK_PENDING, &connection->flags);
@@ -388,6 +397,7 @@ static int conn_khelper(struct drbd_connection *connection, char *cmd)
 
 	drbd_info(connection, "helper command: %s %s %s\n", usermode_helper, cmd, resource_name);
 	/* TODO: conn_bcast_event() ?? */
+	notify_helper(NOTIFY_CALL, NULL, connection, cmd, 0);
 
 	ret = call_usermodehelper(usermode_helper, argv, envp, UMH_WAIT_PROC);
 	if (ret)
@@ -399,6 +409,7 @@ static int conn_khelper(struct drbd_connection *connection, char *cmd)
 			  usermode_helper, cmd, resource_name,
 			  (ret >> 8) & 0xff, ret);
 	/* TODO: conn_bcast_event() ?? */
+	notify_helper(NOTIFY_RESPONSE, NULL, connection, cmd, ret);
 
 	if (ret < 0) /* Ignore any ERRNOs we got. */
 		ret = 0;
@@ -2248,8 +2259,31 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 	return 0;
 }
 
+static void connection_to_info(struct connection_info *info,
+			       struct drbd_connection *connection)
+{
+	info->conn_connection_state = connection->cstate;
+	info->conn_role = conn_highest_peer(connection);
+}
+
+static void peer_device_to_info(struct peer_device_info *info,
+				struct drbd_peer_device *peer_device)
+{
+	struct drbd_device *device = peer_device->device;
+
+	info->peer_repl_state =
+		max_t(enum drbd_conns, C_WF_REPORT_PARAMS, device->state.conn);
+	info->peer_disk_state = device->state.pdsk;
+	info->peer_resync_susp_user = device->state.user_isp;
+	info->peer_resync_susp_peer = device->state.peer_isp;
+	info->peer_resync_susp_dependency = device->state.aftr_isp;
+}
+
 int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 {
+	struct connection_info connection_info;
+	enum drbd_notification_type flags;
+	unsigned int peer_devices = 0;
 	struct drbd_config_context adm_ctx;
 	struct drbd_peer_device *peer_device;
 	struct net_conf *old_net_conf, *new_net_conf = NULL;
@@ -2350,6 +2384,22 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 	connection->peer_addr_len = nla_len(adm_ctx.peer_addr);
 	memcpy(&connection->peer_addr, nla_data(adm_ctx.peer_addr), connection->peer_addr_len);
 
+	idr_for_each_entry(&connection->peer_devices, peer_device, i) {
+		peer_devices++;
+	}
+
+	connection_to_info(&connection_info, connection);
+	flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
+	mutex_lock(&notification_mutex);
+	notify_connection_state(NULL, 0, connection, &connection_info, NOTIFY_CREATE | flags);
+	idr_for_each_entry(&connection->peer_devices, peer_device, i) {
+		struct peer_device_info peer_device_info;
+
+		peer_device_to_info(&peer_device_info, peer_device);
+		flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
+		notify_peer_device_state(NULL, 0, peer_device, &peer_device_info, NOTIFY_CREATE | flags);
+	}
+	mutex_unlock(&notification_mutex);
 	mutex_unlock(&adm_ctx.resource->conf_update);
 
 	rcu_read_lock();
@@ -2431,6 +2481,8 @@ static enum drbd_state_rv conn_try_disconnect(struct drbd_connection *connection
 			drbd_err(connection,
 				"unexpected rv2=%d in conn_try_disconnect()\n",
 				rv2);
+		/* Unlike in DRBD 9, the state engine has generated
+		 * NOTIFY_DESTROY events before clearing connection->net_conf. */
 	}
 	return rv;
 }
@@ -3417,8 +3469,18 @@ drbd_check_resource_name(struct drbd_config_context *adm_ctx)
 	return NO_ERROR;
 }
 
+static void resource_to_info(struct resource_info *info,
+			     struct drbd_resource *resource)
+{
+	info->res_role = conn_highest_role(first_connection(resource));
+	info->res_susp = resource->susp;
+	info->res_susp_nod = resource->susp_nod;
+	info->res_susp_fen = resource->susp_fen;
+}
+
 int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_connection *connection;
 	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct res_opts res_opts;
@@ -3453,14 +3515,32 @@ int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 
 	/* not yet safe for genl_family.parallel_ops */
 	mutex_lock(&resources_mutex);
-	if (!conn_create(adm_ctx.resource_name, &res_opts))
-		retcode = ERR_NOMEM;
+	connection = conn_create(adm_ctx.resource_name, &res_opts);
 	mutex_unlock(&resources_mutex);
+
+	if (connection) {
+		struct resource_info resource_info;
+
+		mutex_lock(&notification_mutex);
+		resource_to_info(&resource_info, connection->resource);
+		notify_resource_state(NULL, 0, connection->resource,
+				      &resource_info, NOTIFY_CREATE);
+		mutex_unlock(&notification_mutex);
+	} else
+		retcode = ERR_NOMEM;
+
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
+static void device_to_info(struct device_info *info,
+			   struct drbd_device *device)
+{
+	info->dev_disk_state = device->state.disk;
+}
+
+
 int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 {
 	struct drbd_config_context adm_ctx;
@@ -3495,6 +3575,36 @@ int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 
 	mutex_lock(&adm_ctx.resource->adm_mutex);
 	retcode = drbd_create_device(&adm_ctx, dh->minor);
+	if (retcode == NO_ERROR) {
+		struct drbd_device *device;
+		struct drbd_peer_device *peer_device;
+		struct device_info info;
+		unsigned int peer_devices = 0;
+		enum drbd_notification_type flags;
+
+		device = minor_to_device(dh->minor);
+		for_each_peer_device(peer_device, device) {
+			if (!has_net_conf(peer_device->connection))
+				continue;
+			peer_devices++;
+		}
+
+		device_to_info(&info, device);
+		mutex_lock(&notification_mutex);
+		flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
+		notify_device_state(NULL, 0, device, &info, NOTIFY_CREATE | flags);
+		for_each_peer_device(peer_device, device) {
+			struct peer_device_info peer_device_info;
+
+			if (!has_net_conf(peer_device->connection))
+				continue;
+			peer_device_to_info(&peer_device_info, peer_device);
+			flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
+			notify_peer_device_state(NULL, 0, peer_device, &peer_device_info,
+						 NOTIFY_CREATE | flags);
+		}
+		mutex_unlock(&notification_mutex);
+	}
 	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
@@ -3503,13 +3613,35 @@ out:
 
 static enum drbd_ret_code adm_del_minor(struct drbd_device *device)
 {
+	struct drbd_peer_device *peer_device;
+
 	if (device->state.disk == D_DISKLESS &&
 	    /* no need to be device->state.conn == C_STANDALONE &&
 	     * we may want to delete a minor from a live replication group.
 	     */
 	    device->state.role == R_SECONDARY) {
+		struct drbd_connection *connection =
+			first_connection(device->resource);
+
 		_drbd_request_state(device, NS(conn, C_WF_REPORT_PARAMS),
 				    CS_VERBOSE + CS_WAIT_COMPLETE);
+
+		/* If the state engine hasn't stopped the sender thread yet, we
+		 * need to flush the sender work queue before generating the
+		 * DESTROY events here. */
+		if (get_t_state(&connection->worker) == RUNNING)
+			drbd_flush_workqueue(&connection->sender_work);
+
+		mutex_lock(&notification_mutex);
+		for_each_peer_device(peer_device, device) {
+			if (!has_net_conf(peer_device->connection))
+				continue;
+			notify_peer_device_state(NULL, 0, peer_device, NULL,
+						 NOTIFY_DESTROY | NOTIFY_CONTINUES);
+		}
+		notify_device_state(NULL, 0, device, NULL, NOTIFY_DESTROY);
+		mutex_unlock(&notification_mutex);
+
 		drbd_delete_device(device);
 		return NO_ERROR;
 	} else
@@ -3546,6 +3678,13 @@ static int adm_del_resource(struct drbd_resource *resource)
 	if (!idr_is_empty(&resource->devices))
 		return ERR_RES_IN_USE;
 
+	/* The state engine has stopped the sender thread, so we don't
+	 * need to flush the sender work queue before generating the
+	 * DESTROY event here. */
+	mutex_lock(&notification_mutex);
+	notify_resource_state(NULL, 0, resource, NULL, NOTIFY_DESTROY);
+	mutex_unlock(&notification_mutex);
+
 	mutex_lock(&resources_mutex);
 	list_del_rcu(&resource->resources);
 	mutex_unlock(&resources_mutex);
@@ -3644,7 +3783,6 @@ finish:
 
 void drbd_bcast_event(struct drbd_device *device, const struct sib_info *sib)
 {
-	static atomic_t drbd_genl_seq = ATOMIC_INIT(2); /* two. */
 	struct sk_buff *msg;
 	struct drbd_genlmsghdr *d_out;
 	unsigned seq;
@@ -3679,3 +3817,484 @@ failed:
 			"Event seq:%u sib_reason:%u\n",
 			err, seq, sib->sib_reason);
 }
+
+static void device_to_statistics(struct device_statistics *s,
+				 struct drbd_device *device)
+{
+	memset(s, 0, sizeof(*s));
+	s->dev_upper_blocked = !may_inc_ap_bio(device);
+	if (get_ldev(device)) {
+		struct drbd_md *md = &device->ldev->md;
+		u64 *history_uuids = (u64 *)s->history_uuids;
+		struct request_queue *q;
+		int n;
+
+		spin_lock_irq(&md->uuid_lock);
+		s->dev_current_uuid = md->uuid[UI_CURRENT];
+		BUILD_BUG_ON(sizeof(s->history_uuids) < UI_HISTORY_END - UI_HISTORY_START + 1);
+		for (n = 0; n < UI_HISTORY_END - UI_HISTORY_START + 1; n++)
+			history_uuids[n] = md->uuid[UI_HISTORY_START + n];
+		for (; n < HISTORY_UUIDS; n++)
+			history_uuids[n] = 0;
+		s->history_uuids_len = HISTORY_UUIDS;
+		spin_unlock_irq(&md->uuid_lock);
+
+		s->dev_disk_flags = md->flags;
+		q = bdev_get_queue(device->ldev->backing_bdev);
+		s->dev_lower_blocked =
+			bdi_congested(&q->backing_dev_info,
+				      (1 << WB_async_congested) |
+				      (1 << WB_sync_congested));
+		put_ldev(device);
+	}
+	s->dev_size = drbd_get_capacity(device->this_bdev);
+	s->dev_read = device->read_cnt;
+	s->dev_write = device->writ_cnt;
+	s->dev_al_writes = device->al_writ_cnt;
+	s->dev_bm_writes = device->bm_writ_cnt;
+	s->dev_upper_pending = atomic_read(&device->ap_bio_cnt);
+	s->dev_lower_pending = atomic_read(&device->local_cnt);
+	s->dev_al_suspended = test_bit(AL_SUSPENDED, &device->flags);
+	s->dev_exposed_data_uuid = device->ed_uuid;
+}
+
+enum mdf_peer_flag {
+	MDF_PEER_CONNECTED =	1 << 0,
+	MDF_PEER_OUTDATED =	1 << 1,
+	MDF_PEER_FENCING =	1 << 2,
+	MDF_PEER_FULL_SYNC =	1 << 3,
+};
+
+static void peer_device_to_statistics(struct peer_device_statistics *s,
+				      struct drbd_peer_device *peer_device)
+{
+	struct drbd_device *device = peer_device->device;
+
+	memset(s, 0, sizeof(*s));
+	s->peer_dev_received = device->recv_cnt;
+	s->peer_dev_sent = device->send_cnt;
+	s->peer_dev_pending = atomic_read(&device->ap_pending_cnt) +
+			      atomic_read(&device->rs_pending_cnt);
+	s->peer_dev_unacked = atomic_read(&device->unacked_cnt);
+	s->peer_dev_out_of_sync = drbd_bm_total_weight(device) << (BM_BLOCK_SHIFT - 9);
+	s->peer_dev_resync_failed = device->rs_failed << (BM_BLOCK_SHIFT - 9);
+	if (get_ldev(device)) {
+		struct drbd_md *md = &device->ldev->md;
+
+		spin_lock_irq(&md->uuid_lock);
+		s->peer_dev_bitmap_uuid = md->uuid[UI_BITMAP];
+		spin_unlock_irq(&md->uuid_lock);
+		s->peer_dev_flags =
+			(drbd_md_test_flag(device->ldev, MDF_CONNECTED_IND) ?
+				MDF_PEER_CONNECTED : 0) +
+			(drbd_md_test_flag(device->ldev, MDF_CONSISTENT) &&
+			 !drbd_md_test_flag(device->ldev, MDF_WAS_UP_TO_DATE) ?
+				MDF_PEER_OUTDATED : 0) +
+			/* FIXME: MDF_PEER_FENCING? */
+			(drbd_md_test_flag(device->ldev, MDF_FULL_SYNC) ?
+				MDF_PEER_FULL_SYNC : 0);
+		put_ldev(device);
+	}
+}
+
+static int nla_put_notification_header(struct sk_buff *msg,
+				       enum drbd_notification_type type)
+{
+	struct drbd_notification_header nh = {
+		.nh_type = type,
+	};
+
+	return drbd_notification_header_to_skb(msg, &nh, true);
+}
+
+void notify_resource_state(struct sk_buff *skb,
+			   unsigned int seq,
+			   struct drbd_resource *resource,
+			   struct resource_info *resource_info,
+			   enum drbd_notification_type type)
+{
+	struct resource_statistics resource_statistics;
+	struct drbd_genlmsghdr *dh;
+	bool multicast = false;
+	int err;
+
+	if (!skb) {
+		seq = atomic_inc_return(&notify_genl_seq);
+		skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
+		err = -ENOMEM;
+		if (!skb)
+			goto failed;
+		multicast = true;
+	}
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_RESOURCE_STATE);
+	if (!dh)
+		goto nla_put_failure;
+	dh->minor = -1U;
+	dh->ret_code = NO_ERROR;
+	if (nla_put_drbd_cfg_context(skb, resource, NULL, NULL) ||
+	    nla_put_notification_header(skb, type) ||
+	    ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
+	     resource_info_to_skb(skb, resource_info, true)))
+		goto nla_put_failure;
+	resource_statistics.res_stat_write_ordering = resource->write_ordering;
+	err = resource_statistics_to_skb(skb, &resource_statistics, !capable(CAP_SYS_ADMIN));
+	if (err)
+		goto nla_put_failure;
+	genlmsg_end(skb, dh);
+	if (multicast) {
+		err = drbd_genl_multicast_events(skb, 0);
+		/* skb has been consumed or freed in netlink_broadcast() */
+		if (err && err != -ESRCH)
+			goto failed;
+	}
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+failed:
+	drbd_err(resource, "Error %d while broadcasting event. Event seq:%u\n",
+			err, seq);
+}
+
+void notify_device_state(struct sk_buff *skb,
+			 unsigned int seq,
+			 struct drbd_device *device,
+			 struct device_info *device_info,
+			 enum drbd_notification_type type)
+{
+	struct device_statistics device_statistics;
+	struct drbd_genlmsghdr *dh;
+	bool multicast = false;
+	int err;
+
+	if (!skb) {
+		seq = atomic_inc_return(&notify_genl_seq);
+		skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
+		err = -ENOMEM;
+		if (!skb)
+			goto failed;
+		multicast = true;
+	}
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_DEVICE_STATE);
+	if (!dh)
+		goto nla_put_failure;
+	dh->minor = device->minor;
+	dh->ret_code = NO_ERROR;
+	if (nla_put_drbd_cfg_context(skb, device->resource, NULL, device) ||
+	    nla_put_notification_header(skb, type) ||
+	    ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
+	     device_info_to_skb(skb, device_info, true)))
+		goto nla_put_failure;
+	device_to_statistics(&device_statistics, device);
+	device_statistics_to_skb(skb, &device_statistics, !capable(CAP_SYS_ADMIN));
+	genlmsg_end(skb, dh);
+	if (multicast) {
+		err = drbd_genl_multicast_events(skb, 0);
+		/* skb has been consumed or freed in netlink_broadcast() */
+		if (err && err != -ESRCH)
+			goto failed;
+	}
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+failed:
+	drbd_err(device, "Error %d while broadcasting event. Event seq:%u\n",
+		 err, seq);
+}
+
+void notify_connection_state(struct sk_buff *skb,
+			     unsigned int seq,
+			     struct drbd_connection *connection,
+			     struct connection_info *connection_info,
+			     enum drbd_notification_type type)
+{
+	struct connection_statistics connection_statistics;
+	struct drbd_genlmsghdr *dh;
+	bool multicast = false;
+	int err;
+
+	if (!skb) {
+		seq = atomic_inc_return(&notify_genl_seq);
+		skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
+		err = -ENOMEM;
+		if (!skb)
+			goto failed;
+		multicast = true;
+	}
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_CONNECTION_STATE);
+	if (!dh)
+		goto nla_put_failure;
+	dh->minor = -1U;
+	dh->ret_code = NO_ERROR;
+	if (nla_put_drbd_cfg_context(skb, connection->resource, connection, NULL) ||
+	    nla_put_notification_header(skb, type) ||
+	    ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
+	     connection_info_to_skb(skb, connection_info, true)))
+		goto nla_put_failure;
+	connection_statistics.conn_congested = test_bit(NET_CONGESTED, &connection->flags);
+	connection_statistics_to_skb(skb, &connection_statistics, !capable(CAP_SYS_ADMIN));
+	genlmsg_end(skb, dh);
+	if (multicast) {
+		err = drbd_genl_multicast_events(skb, 0);
+		/* skb has been consumed or freed in netlink_broadcast() */
+		if (err && err != -ESRCH)
+			goto failed;
+	}
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+failed:
+	drbd_err(connection, "Error %d while broadcasting event. Event seq:%u\n",
+		 err, seq);
+}
+
+void notify_peer_device_state(struct sk_buff *skb,
+			      unsigned int seq,
+			      struct drbd_peer_device *peer_device,
+			      struct peer_device_info *peer_device_info,
+			      enum drbd_notification_type type)
+{
+	struct peer_device_statistics peer_device_statistics;
+	struct drbd_resource *resource = peer_device->device->resource;
+	struct drbd_genlmsghdr *dh;
+	bool multicast = false;
+	int err;
+
+	if (!skb) {
+		seq = atomic_inc_return(&notify_genl_seq);
+		skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
+		err = -ENOMEM;
+		if (!skb)
+			goto failed;
+		multicast = true;
+	}
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_PEER_DEVICE_STATE);
+	if (!dh)
+		goto nla_put_failure;
+	dh->minor = -1U;
+	dh->ret_code = NO_ERROR;
+	if (nla_put_drbd_cfg_context(skb, resource, peer_device->connection, peer_device->device) ||
+	    nla_put_notification_header(skb, type) ||
+	    ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
+	     peer_device_info_to_skb(skb, peer_device_info, true)))
+		goto nla_put_failure;
+	peer_device_to_statistics(&peer_device_statistics, peer_device);
+	peer_device_statistics_to_skb(skb, &peer_device_statistics, !capable(CAP_SYS_ADMIN));
+	genlmsg_end(skb, dh);
+	if (multicast) {
+		err = drbd_genl_multicast_events(skb, 0);
+		/* skb has been consumed or freed in netlink_broadcast() */
+		if (err && err != -ESRCH)
+			goto failed;
+	}
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+failed:
+	drbd_err(peer_device, "Error %d while broadcasting event. Event seq:%u\n",
+		 err, seq);
+}
+
+void notify_helper(enum drbd_notification_type type,
+		   struct drbd_device *device, struct drbd_connection *connection,
+		   const char *name, int status)
+{
+	struct drbd_resource *resource = device ? device->resource : connection->resource;
+	struct drbd_helper_info helper_info;
+	unsigned int seq = atomic_inc_return(&notify_genl_seq);
+	struct sk_buff *skb = NULL;
+	struct drbd_genlmsghdr *dh;
+	int err;
+
+	strlcpy(helper_info.helper_name, name, sizeof(helper_info.helper_name));
+	helper_info.helper_name_len = min(strlen(name), sizeof(helper_info.helper_name));
+	helper_info.helper_status = status;
+
+	skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
+	err = -ENOMEM;
+	if (!skb)
+		goto fail;
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_HELPER);
+	if (!dh)
+		goto fail;
+	dh->minor = device ? device->minor : -1;
+	dh->ret_code = NO_ERROR;
+	mutex_lock(&notification_mutex);
+	if (nla_put_drbd_cfg_context(skb, resource, connection, device) ||
+	    nla_put_notification_header(skb, type) ||
+	    drbd_helper_info_to_skb(skb, &helper_info, true))
+		goto unlock_fail;
+	genlmsg_end(skb, dh);
+	err = drbd_genl_multicast_events(skb, 0);
+	skb = NULL;
+	/* skb has been consumed or freed in netlink_broadcast() */
+	if (err && err != -ESRCH)
+		goto unlock_fail;
+	mutex_unlock(&notification_mutex);
+	return;
+
+unlock_fail:
+	mutex_unlock(&notification_mutex);
+fail:
+	nlmsg_free(skb);
+	drbd_err(resource, "Error %d while broadcasting event. Event seq:%u\n",
+		 err, seq);
+}
+
+static void notify_initial_state_done(struct sk_buff *skb, unsigned int seq)
+{
+	struct drbd_genlmsghdr *dh;
+	int err;
+
+	err = -EMSGSIZE;
+	dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_INITIAL_STATE_DONE);
+	if (!dh)
+		goto nla_put_failure;
+	dh->minor = -1U;
+	dh->ret_code = NO_ERROR;
+	if (nla_put_notification_header(skb, NOTIFY_EXISTS))
+		goto nla_put_failure;
+	genlmsg_end(skb, dh);
+	return;
+
+nla_put_failure:
+	nlmsg_free(skb);
+	pr_err("Error %d sending event. Event seq:%u\n", err, seq);
+}
+
+static void free_state_changes(struct list_head *list)
+{
+	while (!list_empty(list)) {
+		struct drbd_state_change *state_change =
+			list_first_entry(list, struct drbd_state_change, list);
+		list_del(&state_change->list);
+		forget_state_change(state_change);
+	}
+}
+
+static unsigned int notifications_for_state_change(struct drbd_state_change *state_change)
+{
+	return 1 +
+	       state_change->n_connections +
+	       state_change->n_devices +
+	       state_change->n_devices * state_change->n_connections;
+}
+
+static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0];
+	unsigned int seq = cb->args[2];
+	unsigned int n;
+	enum drbd_notification_type flags = 0;
+
+	/* There is no need for taking notification_mutex here: it doesn't
+	   matter if the initial state events mix with later state chage
+	   events; we can always tell the events apart by the NOTIFY_EXISTS
+	   flag. */
+
+	cb->args[5]--;
+	if (cb->args[5] == 1) {
+		notify_initial_state_done(skb, seq);
+		goto out;
+	}
+	n = cb->args[4]++;
+	if (cb->args[4] < cb->args[3])
+		flags |= NOTIFY_CONTINUES;
+	if (n < 1) {
+		notify_resource_state_change(skb, seq, state_change->resource,
+					     NOTIFY_EXISTS | flags);
+		goto next;
+	}
+	n--;
+	if (n < state_change->n_connections) {
+		notify_connection_state_change(skb, seq, &state_change->connections[n],
+					       NOTIFY_EXISTS | flags);
+		goto next;
+	}
+	n -= state_change->n_connections;
+	if (n < state_change->n_devices) {
+		notify_device_state_change(skb, seq, &state_change->devices[n],
+					   NOTIFY_EXISTS | flags);
+		goto next;
+	}
+	n -= state_change->n_devices;
+	if (n < state_change->n_devices * state_change->n_connections) {
+		notify_peer_device_state_change(skb, seq, &state_change->peer_devices[n],
+						NOTIFY_EXISTS | flags);
+		goto next;
+	}
+
+next:
+	if (cb->args[4] == cb->args[3]) {
+		struct drbd_state_change *next_state_change =
+			list_entry(state_change->list.next,
+				   struct drbd_state_change, list);
+		cb->args[0] = (long)next_state_change;
+		cb->args[3] = notifications_for_state_change(next_state_change);
+		cb->args[4] = 0;
+	}
+out:
+	return skb->len;
+}
+
+int drbd_adm_get_initial_state(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct drbd_resource *resource;
+	LIST_HEAD(head);
+
+	if (cb->args[5] >= 1) {
+		if (cb->args[5] > 1)
+			return get_initial_state(skb, cb);
+		if (cb->args[0]) {
+			struct drbd_state_change *state_change =
+				(struct drbd_state_change *)cb->args[0];
+
+			/* connect list to head */
+			list_add(&head, &state_change->list);
+			free_state_changes(&head);
+		}
+		return 0;
+	}
+
+	cb->args[5] = 2;  /* number of iterations */
+	mutex_lock(&resources_mutex);
+	for_each_resource(resource, &drbd_resources) {
+		struct drbd_state_change *state_change;
+
+		state_change = remember_old_state(resource, GFP_KERNEL);
+		if (!state_change) {
+			if (!list_empty(&head))
+				free_state_changes(&head);
+			mutex_unlock(&resources_mutex);
+			return -ENOMEM;
+		}
+		copy_old_to_new_state_change(state_change);
+		list_add_tail(&state_change->list, &head);
+		cb->args[5] += notifications_for_state_change(state_change);
+	}
+	mutex_unlock(&resources_mutex);
+
+	if (!list_empty(&head)) {
+		struct drbd_state_change *state_change =
+			list_entry(head.next, struct drbd_state_change, list);
+		cb->args[0] = (long)state_change;
+		cb->args[3] = notifications_for_state_change(state_change);
+		list_del(&head);  /* detach list from head */
+	}
+
+	cb->args[2] = cb->nlh->nlmsg_seq;
+	return get_initial_state(skb, cb);
+}