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: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

drivers/block/drbd/drbd_int.h

@@ -667,6 +667,8 @@ enum {
 	DEVICE_WORK_PENDING,	/* tell worker that some device has pending work */
 };
 
+enum which_state { NOW, OLD = NOW, NEW };
+
 struct drbd_resource {
 	char *name;
 #ifdef CONFIG_DEBUG_FS
@@ -785,6 +787,17 @@ struct drbd_connection {
 	} send;
 };
 
+static inline bool has_net_conf(struct drbd_connection *connection)
+{
+	bool has_net_conf;
+
+	rcu_read_lock();
+	has_net_conf = rcu_dereference(connection->net_conf);
+	rcu_read_unlock();
+
+	return has_net_conf;
+}
+
 void __update_timing_details(
 		struct drbd_thread_timing_details *tdp,
 		unsigned int *cb_nr,
@@ -1017,6 +1030,12 @@ static inline struct drbd_peer_device *first_peer_device(struct drbd_device *dev
 	return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
 }
 
+static inline struct drbd_peer_device *
+conn_peer_device(struct drbd_connection *connection, int volume_number)
+{
+	return idr_find(&connection->peer_devices, volume_number);
+}
+
 #define for_each_resource(resource, _resources) \
 	list_for_each_entry(resource, _resources, resources)
 
@@ -1451,6 +1470,9 @@ extern int is_valid_ar_handle(struct drbd_request *, sector_t);
 
 
 /* drbd_nl.c */
+
+extern struct mutex notification_mutex;
+
 extern void drbd_suspend_io(struct drbd_device *device);
 extern void drbd_resume_io(struct drbd_device *device);
 extern char *ppsize(char *buf, unsigned long long size);
@@ -1665,6 +1687,29 @@ struct sib_info {
 };
 void drbd_bcast_event(struct drbd_device *device, const struct sib_info *sib);
 
+extern void notify_resource_state(struct sk_buff *,
+				  unsigned int,
+				  struct drbd_resource *,
+				  struct resource_info *,
+				  enum drbd_notification_type);
+extern void notify_device_state(struct sk_buff *,
+				unsigned int,
+				struct drbd_device *,
+				struct device_info *,
+				enum drbd_notification_type);
+extern void notify_connection_state(struct sk_buff *,
+				    unsigned int,
+				    struct drbd_connection *,
+				    struct connection_info *,
+				    enum drbd_notification_type);
+extern void notify_peer_device_state(struct sk_buff *,
+				     unsigned int,
+				     struct drbd_peer_device *,
+				     struct peer_device_info *,
+				     enum drbd_notification_type);
+extern void notify_helper(enum drbd_notification_type, struct drbd_device *,
+			  struct drbd_connection *, const char *, int);
+
 /*
  * inline helper functions
  *************************/

drivers/block/drbd/drbd_receiver.c

@@ -1508,12 +1508,6 @@ static void conn_wait_active_ee_empty(struct drbd_connection *connection)
 	rcu_read_unlock();
 }
 
-static struct drbd_peer_device *
-conn_peer_device(struct drbd_connection *connection, int volume_number)
-{
-	return idr_find(&connection->peer_devices, volume_number);
-}
-
 static int receive_Barrier(struct drbd_connection *connection, struct packet_info *pi)
 {
 	int rv;

drivers/block/drbd/drbd_state.c

@@ -29,6 +29,7 @@
 #include "drbd_int.h"
 #include "drbd_protocol.h"
 #include "drbd_req.h"
+#include "drbd_state_change.h"
 
 struct after_state_chg_work {
 	struct drbd_work w;
@@ -37,6 +38,7 @@ struct after_state_chg_work {
 	union drbd_state ns;
 	enum chg_state_flags flags;
 	struct completion *done;
+	struct drbd_state_change *state_change;
 };
 
 enum sanitize_state_warnings {
@@ -48,9 +50,266 @@ enum sanitize_state_warnings {
 	IMPLICITLY_UPGRADED_PDSK,
 };
 
+static void count_objects(struct drbd_resource *resource,
+			  unsigned int *n_devices,
+			  unsigned int *n_connections)
+{
+	struct drbd_device *device;
+	struct drbd_connection *connection;
+	int vnr;
+
+	*n_devices = 0;
+	*n_connections = 0;
+
+	idr_for_each_entry(&resource->devices, device, vnr)
+		(*n_devices)++;
+	for_each_connection(connection, resource) {
+		if (!has_net_conf(connection))
+			continue;
+		(*n_connections)++;
+	}
+}
+
+static struct drbd_state_change *alloc_state_change(unsigned int n_devices, unsigned int n_connections, gfp_t gfp)
+{
+	struct drbd_state_change *state_change;
+	unsigned int size, n;
+
+	size = sizeof(struct drbd_state_change) +
+	       n_devices * sizeof(struct drbd_device_state_change) +
+	       n_connections * sizeof(struct drbd_connection_state_change) +
+	       n_devices * n_connections * sizeof(struct drbd_peer_device_state_change);
+	state_change = kmalloc(size, gfp);
+	if (!state_change)
+		return NULL;
+	state_change->n_devices = n_devices;
+	state_change->n_connections = n_connections;
+	state_change->devices = (void *)(state_change + 1);
+	state_change->connections = (void *)&state_change->devices[n_devices];
+	state_change->peer_devices = (void *)&state_change->connections[n_connections];
+	state_change->resource->resource = NULL;
+	for (n = 0; n < n_devices; n++)
+		state_change->devices[n].device = NULL;
+	for (n = 0; n < n_connections; n++)
+		state_change->connections[n].connection = NULL;
+	return state_change;
+}
+
+struct drbd_state_change *remember_old_state(struct drbd_resource *resource, gfp_t gfp)
+{
+	struct drbd_state_change *state_change;
+	struct drbd_device *device;
+	unsigned int n_devices;
+	struct drbd_connection *connection;
+	unsigned int n_connections;
+	int vnr;
+
+	struct drbd_device_state_change *device_state_change;
+	struct drbd_peer_device_state_change *peer_device_state_change;
+	struct drbd_connection_state_change *connection_state_change;
+
+retry:
+	rcu_read_lock();
+	count_objects(resource, &n_devices, &n_connections);
+	rcu_read_unlock();
+	state_change = alloc_state_change(n_devices, n_connections, gfp);
+	if (!state_change)
+		return NULL;
+
+	rcu_read_lock();
+	count_objects(resource, &n_devices, &n_connections);
+	if (n_devices != state_change->n_devices ||
+	    n_connections != state_change->n_connections) {
+		kfree(state_change);
+		rcu_read_unlock();
+		goto retry;
+	}
+
+	kref_get(&resource->kref);
+	state_change->resource->resource = resource;
+	state_change->resource->role[OLD] =
+		conn_highest_role(first_connection(resource));
+	state_change->resource->susp[OLD] = resource->susp;
+	state_change->resource->susp_nod[OLD] = resource->susp_nod;
+	state_change->resource->susp_fen[OLD] = resource->susp_fen;
+
+	device_state_change = state_change->devices;
+	peer_device_state_change = state_change->peer_devices;
+	idr_for_each_entry(&resource->devices, device, vnr) {
+		kref_get(&device->kref);
+		device_state_change->device = device;
+		device_state_change->disk_state[OLD] = device->state.disk;
+
+		/* The peer_devices for each device have to be enumerated in
+		   the order of the connections. We may not use for_each_peer_device() here. */
+		for_each_connection(connection, resource) {
+			struct drbd_peer_device *peer_device;
+
+			if (!has_net_conf(connection))
+				continue;
+			peer_device = conn_peer_device(connection, device->vnr);
+			peer_device_state_change->peer_device = peer_device;
+			peer_device_state_change->disk_state[OLD] =
+				device->state.pdsk;
+			peer_device_state_change->repl_state[OLD] =
+				max_t(enum drbd_conns,
+				      C_WF_REPORT_PARAMS, device->state.conn);
+			peer_device_state_change->resync_susp_user[OLD] =
+				device->state.user_isp;
+			peer_device_state_change->resync_susp_peer[OLD] =
+				device->state.peer_isp;
+			peer_device_state_change->resync_susp_dependency[OLD] =
+				device->state.aftr_isp;
+			peer_device_state_change++;
+		}
+		device_state_change++;
+	}
+
+	connection_state_change = state_change->connections;
+	for_each_connection(connection, resource) {
+		if (!has_net_conf(connection))
+			continue;
+		kref_get(&connection->kref);
+		connection_state_change->connection = connection;
+		connection_state_change->cstate[OLD] =
+			connection->cstate;
+		connection_state_change->peer_role[OLD] =
+			conn_highest_peer(connection);
+		connection_state_change++;
+	}
+	rcu_read_unlock();
+
+	return state_change;
+}
+
+static void remember_new_state(struct drbd_state_change *state_change)
+{
+	struct drbd_resource_state_change *resource_state_change;
+	struct drbd_resource *resource;
+	unsigned int n;
+
+	if (!state_change)
+		return;
+
+	resource_state_change = &state_change->resource[0];
+	resource = resource_state_change->resource;
+
+	resource_state_change->role[NEW] =
+		conn_highest_role(first_connection(resource));
+	resource_state_change->susp[NEW] = resource->susp;
+	resource_state_change->susp_nod[NEW] = resource->susp_nod;
+	resource_state_change->susp_fen[NEW] = resource->susp_fen;
+
+	for (n = 0; n < state_change->n_devices; n++) {
+		struct drbd_device_state_change *device_state_change =
+			&state_change->devices[n];
+		struct drbd_device *device = device_state_change->device;
+
+		device_state_change->disk_state[NEW] = device->state.disk;
+	}
+
+	for (n = 0; n < state_change->n_connections; n++) {
+		struct drbd_connection_state_change *connection_state_change =
+			&state_change->connections[n];
+		struct drbd_connection *connection =
+			connection_state_change->connection;
+
+		connection_state_change->cstate[NEW] = connection->cstate;
+		connection_state_change->peer_role[NEW] =
+			conn_highest_peer(connection);
+	}
+
+	for (n = 0; n < state_change->n_devices * state_change->n_connections; n++) {
+		struct drbd_peer_device_state_change *peer_device_state_change =
+			&state_change->peer_devices[n];
+		struct drbd_device *device =
+			peer_device_state_change->peer_device->device;
+		union drbd_dev_state state = device->state;
+
+		peer_device_state_change->disk_state[NEW] = state.pdsk;
+		peer_device_state_change->repl_state[NEW] =
+			max_t(enum drbd_conns, C_WF_REPORT_PARAMS, state.conn);
+		peer_device_state_change->resync_susp_user[NEW] =
+			state.user_isp;
+		peer_device_state_change->resync_susp_peer[NEW] =
+			state.peer_isp;
+		peer_device_state_change->resync_susp_dependency[NEW] =
+			state.aftr_isp;
+	}
+}
+
+void copy_old_to_new_state_change(struct drbd_state_change *state_change)
+{
+	struct drbd_resource_state_change *resource_state_change = &state_change->resource[0];
+	unsigned int n_device, n_connection, n_peer_device, n_peer_devices;
+
+#define OLD_TO_NEW(x) \
+	(x[NEW] = x[OLD])
+
+	OLD_TO_NEW(resource_state_change->role);
+	OLD_TO_NEW(resource_state_change->susp);
+	OLD_TO_NEW(resource_state_change->susp_nod);
+	OLD_TO_NEW(resource_state_change->susp_fen);
+
+	for (n_connection = 0; n_connection < state_change->n_connections; n_connection++) {
+		struct drbd_connection_state_change *connection_state_change =
+				&state_change->connections[n_connection];
+
+		OLD_TO_NEW(connection_state_change->peer_role);
+		OLD_TO_NEW(connection_state_change->cstate);
+	}
+
+	for (n_device = 0; n_device < state_change->n_devices; n_device++) {
+		struct drbd_device_state_change *device_state_change =
+			&state_change->devices[n_device];
+
+		OLD_TO_NEW(device_state_change->disk_state);
+	}
+
+	n_peer_devices = state_change->n_devices * state_change->n_connections;
+	for (n_peer_device = 0; n_peer_device < n_peer_devices; n_peer_device++) {
+		struct drbd_peer_device_state_change *p =
+			&state_change->peer_devices[n_peer_device];
+
+		OLD_TO_NEW(p->disk_state);
+		OLD_TO_NEW(p->repl_state);
+		OLD_TO_NEW(p->resync_susp_user);
+		OLD_TO_NEW(p->resync_susp_peer);
+		OLD_TO_NEW(p->resync_susp_dependency);
+	}
+
+#undef OLD_TO_NEW
+}
+
+void forget_state_change(struct drbd_state_change *state_change)
+{
+	unsigned int n;
+
+	if (!state_change)
+		return;
+
+	if (state_change->resource->resource)
+		kref_put(&state_change->resource->resource->kref, drbd_destroy_resource);
+	for (n = 0; n < state_change->n_devices; n++) {
+		struct drbd_device *device = state_change->devices[n].device;
+
+		if (device)
+			kref_put(&device->kref, drbd_destroy_device);
+	}
+	for (n = 0; n < state_change->n_connections; n++) {
+		struct drbd_connection *connection =
+			state_change->connections[n].connection;
+
+		if (connection)
+			kref_put(&connection->kref, drbd_destroy_connection);
+	}
+	kfree(state_change);
+}
+
 static int w_after_state_ch(struct drbd_work *w, int unused);
 static void after_state_ch(struct drbd_device *device, union drbd_state os,
-			   union drbd_state ns, enum chg_state_flags flags);
+			   union drbd_state ns, enum chg_state_flags flags,
+			   struct drbd_state_change *);
 static enum drbd_state_rv is_valid_state(struct drbd_device *, union drbd_state);
 static enum drbd_state_rv is_valid_soft_transition(union drbd_state, union drbd_state, struct drbd_connection *);
 static enum drbd_state_rv is_valid_transition(union drbd_state os, union drbd_state ns);
@@ -93,6 +352,7 @@ static enum drbd_role max_role(enum drbd_role role1, enum drbd_role role2)
 		return R_SECONDARY;
 	return R_UNKNOWN;
 }
+
 static enum drbd_role min_role(enum drbd_role role1, enum drbd_role role2)
 {
 	if (role1 == R_UNKNOWN || role2 == R_UNKNOWN)
@@ -983,6 +1243,7 @@ _drbd_set_state(struct drbd_device *device, union drbd_state ns,
 	enum drbd_state_rv rv = SS_SUCCESS;
 	enum sanitize_state_warnings ssw;
 	struct after_state_chg_work *ascw;
+	struct drbd_state_change *state_change;
 
 	os = drbd_read_state(device);
 
@@ -1037,6 +1298,9 @@ _drbd_set_state(struct drbd_device *device, union drbd_state ns,
 	if (!is_sync_state(os.conn) && is_sync_state(ns.conn))
 		clear_bit(RS_DONE, &device->flags);
 
+	/* FIXME: Have any flags been set earlier in this function already? */
+	state_change = remember_old_state(device->resource, GFP_ATOMIC);
+
 	/* changes to local_cnt and device flags should be visible before
 	 * changes to state, which again should be visible before anything else
 	 * depending on that change happens. */
@@ -1047,6 +1311,8 @@ _drbd_set_state(struct drbd_device *device, union drbd_state ns,
 	device->resource->susp_fen = ns.susp_fen;
 	smp_wmb();
 
+	remember_new_state(state_change);
+
 	/* put replicated vs not-replicated requests in seperate epochs */
 	if (drbd_should_do_remote((union drbd_dev_state)os.i) !=
 	    drbd_should_do_remote((union drbd_dev_state)ns.i))
@@ -1184,6 +1450,7 @@ _drbd_set_state(struct drbd_device *device, union drbd_state ns,
 		ascw->w.cb = w_after_state_ch;
 		ascw->device = device;
 		ascw->done = done;
+		ascw->state_change = state_change;
 		drbd_queue_work(&connection->sender_work,
 				&ascw->w);
 	} else {
@@ -1199,7 +1466,8 @@ static int w_after_state_ch(struct drbd_work *w, int unused)
 		container_of(w, struct after_state_chg_work, w);
 	struct drbd_device *device = ascw->device;
 
-	after_state_ch(device, ascw->os, ascw->ns, ascw->flags);
+	after_state_ch(device, ascw->os, ascw->ns, ascw->flags, ascw->state_change);
+	forget_state_change(ascw->state_change);
 	if (ascw->flags & CS_WAIT_COMPLETE)
 		complete(ascw->done);
 	kfree(ascw);
@@ -1245,6 +1513,139 @@ int drbd_bitmap_io_from_worker(struct drbd_device *device,
 	return rv;
 }
 
+void notify_resource_state_change(struct sk_buff *skb,
+				  unsigned int seq,
+				  struct drbd_resource_state_change *resource_state_change,
+				  enum drbd_notification_type type)
+{
+	struct drbd_resource *resource = resource_state_change->resource;
+	struct resource_info resource_info = {
+		.res_role = resource_state_change->role[NEW],
+		.res_susp = resource_state_change->susp[NEW],
+		.res_susp_nod = resource_state_change->susp_nod[NEW],
+		.res_susp_fen = resource_state_change->susp_fen[NEW],
+	};
+
+	notify_resource_state(skb, seq, resource, &resource_info, type);
+}
+
+void notify_connection_state_change(struct sk_buff *skb,
+				    unsigned int seq,
+				    struct drbd_connection_state_change *connection_state_change,
+				    enum drbd_notification_type type)
+{
+	struct drbd_connection *connection = connection_state_change->connection;
+	struct connection_info connection_info = {
+		.conn_connection_state = connection_state_change->cstate[NEW],
+		.conn_role = connection_state_change->peer_role[NEW],
+	};
+
+	notify_connection_state(skb, seq, connection, &connection_info, type);
+}
+
+void notify_device_state_change(struct sk_buff *skb,
+				unsigned int seq,
+				struct drbd_device_state_change *device_state_change,
+				enum drbd_notification_type type)
+{
+	struct drbd_device *device = device_state_change->device;
+	struct device_info device_info = {
+		.dev_disk_state = device_state_change->disk_state[NEW],
+	};
+
+	notify_device_state(skb, seq, device, &device_info, type);
+}
+
+void notify_peer_device_state_change(struct sk_buff *skb,
+				     unsigned int seq,
+				     struct drbd_peer_device_state_change *p,
+				     enum drbd_notification_type type)
+{
+	struct drbd_peer_device *peer_device = p->peer_device;
+	struct peer_device_info peer_device_info = {
+		.peer_repl_state = p->repl_state[NEW],
+		.peer_disk_state = p->disk_state[NEW],
+		.peer_resync_susp_user = p->resync_susp_user[NEW],
+		.peer_resync_susp_peer = p->resync_susp_peer[NEW],
+		.peer_resync_susp_dependency = p->resync_susp_dependency[NEW],
+	};
+
+	notify_peer_device_state(skb, seq, peer_device, &peer_device_info, type);
+}
+
+static void broadcast_state_change(struct drbd_state_change *state_change)
+{
+	struct drbd_resource_state_change *resource_state_change = &state_change->resource[0];
+	bool resource_state_has_changed;
+	unsigned int n_device, n_connection, n_peer_device, n_peer_devices;
+	void (*last_func)(struct sk_buff *, unsigned int, void *,
+			  enum drbd_notification_type) = NULL;
+	void *uninitialized_var(last_arg);
+
+#define HAS_CHANGED(state) ((state)[OLD] != (state)[NEW])
+#define FINAL_STATE_CHANGE(type) \
+	({ if (last_func) \
+		last_func(NULL, 0, last_arg, type); \
+	})
+#define REMEMBER_STATE_CHANGE(func, arg, type) \
+	({ FINAL_STATE_CHANGE(type | NOTIFY_CONTINUES); \
+	   last_func = (typeof(last_func))func; \
+	   last_arg = arg; \
+	 })
+
+	mutex_lock(&notification_mutex);
+
+	resource_state_has_changed =
+	    HAS_CHANGED(resource_state_change->role) ||
+	    HAS_CHANGED(resource_state_change->susp) ||
+	    HAS_CHANGED(resource_state_change->susp_nod) ||
+	    HAS_CHANGED(resource_state_change->susp_fen);
+
+	if (resource_state_has_changed)
+		REMEMBER_STATE_CHANGE(notify_resource_state_change,
+				      resource_state_change, NOTIFY_CHANGE);
+
+	for (n_connection = 0; n_connection < state_change->n_connections; n_connection++) {
+		struct drbd_connection_state_change *connection_state_change =
+				&state_change->connections[n_connection];
+
+		if (HAS_CHANGED(connection_state_change->peer_role) ||
+		    HAS_CHANGED(connection_state_change->cstate))
+			REMEMBER_STATE_CHANGE(notify_connection_state_change,
+					      connection_state_change, NOTIFY_CHANGE);
+	}
+
+	for (n_device = 0; n_device < state_change->n_devices; n_device++) {
+		struct drbd_device_state_change *device_state_change =
+			&state_change->devices[n_device];
+
+		if (HAS_CHANGED(device_state_change->disk_state))
+			REMEMBER_STATE_CHANGE(notify_device_state_change,
+					      device_state_change, NOTIFY_CHANGE);
+	}
+
+	n_peer_devices = state_change->n_devices * state_change->n_connections;
+	for (n_peer_device = 0; n_peer_device < n_peer_devices; n_peer_device++) {
+		struct drbd_peer_device_state_change *p =
+			&state_change->peer_devices[n_peer_device];
+
+		if (HAS_CHANGED(p->disk_state) ||
+		    HAS_CHANGED(p->repl_state) ||
+		    HAS_CHANGED(p->resync_susp_user) ||
+		    HAS_CHANGED(p->resync_susp_peer) ||
+		    HAS_CHANGED(p->resync_susp_dependency))
+			REMEMBER_STATE_CHANGE(notify_peer_device_state_change,
+					      p, NOTIFY_CHANGE);
+	}
+
+	FINAL_STATE_CHANGE(NOTIFY_CHANGE);
+	mutex_unlock(&notification_mutex);
+
+#undef HAS_CHANGED
+#undef FINAL_STATE_CHANGE
+#undef REMEMBER_STATE_CHANGE
+}
+
 /**
  * after_state_ch() - Perform after state change actions that may sleep
  * @device:	DRBD device.
@@ -1253,13 +1654,16 @@ int drbd_bitmap_io_from_worker(struct drbd_device *device,
  * @flags:	Flags
  */
 static void after_state_ch(struct drbd_device *device, union drbd_state os,
-			   union drbd_state ns, enum chg_state_flags flags)
+			   union drbd_state ns, enum chg_state_flags flags,
+			   struct drbd_state_change *state_change)
 {
 	struct drbd_resource *resource = device->resource;
 	struct drbd_peer_device *peer_device = first_peer_device(device);
 	struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
 	struct sib_info sib;
 
+	broadcast_state_change(state_change);
+
 	sib.sib_reason = SIB_STATE_CHANGE;
 	sib.os = os;
 	sib.ns = ns;
@@ -1572,6 +1976,7 @@ struct after_conn_state_chg_work {
 	union drbd_state ns_max; /* new, max state, over all devices */
 	enum chg_state_flags flags;
 	struct drbd_connection *connection;
+	struct drbd_state_change *state_change;
 };
 
 static int w_after_conn_state_ch(struct drbd_work *w, int unused)
@@ -1584,6 +1989,8 @@ static int w_after_conn_state_ch(struct drbd_work *w, int unused)
 	struct drbd_peer_device *peer_device;
 	int vnr;
 
+	broadcast_state_change(acscw->state_change);
+	forget_state_change(acscw->state_change);
 	kfree(acscw);
 
 	/* Upon network configuration, we need to start the receiver */
@@ -1593,6 +2000,13 @@ static int w_after_conn_state_ch(struct drbd_work *w, int unused)
 	if (oc == C_DISCONNECTING && ns_max.conn == C_STANDALONE) {
 		struct net_conf *old_conf;
 
+		mutex_lock(&notification_mutex);
+		idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
+			notify_peer_device_state(NULL, 0, peer_device, NULL,
+						 NOTIFY_DESTROY | NOTIFY_CONTINUES);
+		notify_connection_state(NULL, 0, connection, NULL, NOTIFY_DESTROY);
+		mutex_unlock(&notification_mutex);
+
 		mutex_lock(&connection->resource->conf_update);
 		old_conf = connection->net_conf;
 		connection->my_addr_len = 0;
@@ -1823,6 +2237,7 @@ _conn_request_state(struct drbd_connection *connection, union drbd_state mask, u
 	enum drbd_conns oc = connection->cstate;
 	union drbd_state ns_max, ns_min, os;
 	bool have_mutex = false;
+	struct drbd_state_change *state_change;
 
 	if (mask.conn) {
 		rv = is_valid_conn_transition(oc, val.conn);
@@ -1868,10 +2283,12 @@ _conn_request_state(struct drbd_connection *connection, union drbd_state mask, u
 			goto abort;
 	}
 
+	state_change = remember_old_state(connection->resource, GFP_ATOMIC);
 	conn_old_common_state(connection, &os, &flags);
 	flags |= CS_DC_SUSP;
 	conn_set_state(connection, mask, val, &ns_min, &ns_max, flags);
 	conn_pr_state_change(connection, os, ns_max, flags);
+	remember_new_state(state_change);
 
 	acscw = kmalloc(sizeof(*acscw), GFP_ATOMIC);
 	if (acscw) {
@@ -1882,6 +2299,7 @@ _conn_request_state(struct drbd_connection *connection, union drbd_state mask, u
 		acscw->w.cb = w_after_conn_state_ch;
 		kref_get(&connection->kref);
 		acscw->connection = connection;
+		acscw->state_change = state_change;
 		drbd_queue_work(&connection->sender_work, &acscw->w);
 	} else {
 		drbd_err(connection, "Could not kmalloc an acscw\n");

drivers/block/drbd/drbd_state_change.h

+#ifndef DRBD_STATE_CHANGE_H
+#define DRBD_STATE_CHANGE_H
+
+struct drbd_resource_state_change {
+	struct drbd_resource *resource;
+	enum drbd_role role[2];
+	bool susp[2];
+	bool susp_nod[2];
+	bool susp_fen[2];
+};
+
+struct drbd_device_state_change {
+	struct drbd_device *device;
+	enum drbd_disk_state disk_state[2];
+};
+
+struct drbd_connection_state_change {
+	struct drbd_connection *connection;
+	enum drbd_conns cstate[2];  /* drbd9: enum drbd_conn_state */
+	enum drbd_role peer_role[2];
+};
+
+struct drbd_peer_device_state_change {
+	struct drbd_peer_device *peer_device;
+	enum drbd_disk_state disk_state[2];
+	enum drbd_conns repl_state[2];  /* drbd9: enum drbd_repl_state */
+	bool resync_susp_user[2];
+	bool resync_susp_peer[2];
+	bool resync_susp_dependency[2];
+};
+
+struct drbd_state_change {
+	struct list_head list;
+	unsigned int n_devices;
+	unsigned int n_connections;
+	struct drbd_resource_state_change resource[1];
+	struct drbd_device_state_change *devices;
+	struct drbd_connection_state_change *connections;
+	struct drbd_peer_device_state_change *peer_devices;
+};
+
+extern struct drbd_state_change *remember_old_state(struct drbd_resource *, gfp_t);
+extern void copy_old_to_new_state_change(struct drbd_state_change *);
+extern void forget_state_change(struct drbd_state_change *);
+
+extern void notify_resource_state_change(struct sk_buff *,
+					 unsigned int,
+					 struct drbd_resource_state_change *,
+					 enum drbd_notification_type type);
+extern void notify_connection_state_change(struct sk_buff *,
+					   unsigned int,
+					   struct drbd_connection_state_change *,
+					   enum drbd_notification_type type);
+extern void notify_device_state_change(struct sk_buff *,
+				       unsigned int,
+				       struct drbd_device_state_change *,
+				       enum drbd_notification_type type);
+extern void notify_peer_device_state_change(struct sk_buff *,
+					    unsigned int,
+					    struct drbd_peer_device_state_change *,
+					    enum drbd_notification_type type);
+
+#endif  /* DRBD_STATE_CHANGE_H */

include/linux/drbd.h

@@ -339,6 +339,8 @@ enum drbd_state_rv {
 #define MDF_AL_CLEAN		(1 << 7)
 #define MDF_AL_DISABLED		(1 << 8)
 
+#define MAX_PEERS 32
+
 enum drbd_uuid_index {
 	UI_CURRENT,
 	UI_BITMAP,
@@ -349,12 +351,26 @@ enum drbd_uuid_index {
 	UI_EXTENDED_SIZE   /* Everything. */
 };
 
+#define HISTORY_UUIDS MAX_PEERS
+
 enum drbd_timeout_flag {
 	UT_DEFAULT      = 0,
 	UT_DEGRADED     = 1,
 	UT_PEER_OUTDATED = 2,
 };
 
+enum drbd_notification_type {
+	NOTIFY_EXISTS,
+	NOTIFY_CREATE,
+	NOTIFY_CHANGE,
+	NOTIFY_DESTROY,
+	NOTIFY_CALL,
+	NOTIFY_RESPONSE,
+
+	NOTIFY_CONTINUES = 0x8000,
+	NOTIFY_FLAGS = NOTIFY_CONTINUES,
+};
+
 #define UUID_JUST_CREATED ((__u64)4)
 
 enum write_ordering_e {

include/linux/drbd_genl.h

@@ -250,6 +250,76 @@ GENL_struct(DRBD_NLA_DETACH_PARMS, 13, detach_parms,
 	__flg_field(1, DRBD_GENLA_F_MANDATORY,	force_detach)
 )
 
+GENL_struct(DRBD_NLA_RESOURCE_INFO, 15, resource_info,
+	__u32_field(1, 0, res_role)
+	__flg_field(2, 0, res_susp)
+	__flg_field(3, 0, res_susp_nod)
+	__flg_field(4, 0, res_susp_fen)
+	/* __flg_field(5, 0, res_weak) */
+)
+
+GENL_struct(DRBD_NLA_DEVICE_INFO, 16, device_info,
+	__u32_field(1, 0, dev_disk_state)
+)
+
+GENL_struct(DRBD_NLA_CONNECTION_INFO, 17, connection_info,
+	__u32_field(1, 0, conn_connection_state)
+	__u32_field(2, 0, conn_role)
+)
+
+GENL_struct(DRBD_NLA_PEER_DEVICE_INFO, 18, peer_device_info,
+	__u32_field(1, 0, peer_repl_state)
+	__u32_field(2, 0, peer_disk_state)
+	__u32_field(3, 0, peer_resync_susp_user)
+	__u32_field(4, 0, peer_resync_susp_peer)
+	__u32_field(5, 0, peer_resync_susp_dependency)
+)
+
+GENL_struct(DRBD_NLA_RESOURCE_STATISTICS, 19, resource_statistics,
+	__u32_field(1, 0, res_stat_write_ordering)
+)
+
+GENL_struct(DRBD_NLA_DEVICE_STATISTICS, 20, device_statistics,
+	__u64_field(1, 0, dev_size)  /* (sectors) */
+	__u64_field(2, 0, dev_read)  /* (sectors) */
+	__u64_field(3, 0, dev_write)  /* (sectors) */
+	__u64_field(4, 0, dev_al_writes)  /* activity log writes (count) */
+	__u64_field(5, 0, dev_bm_writes)  /*  bitmap writes  (count) */
+	__u32_field(6, 0, dev_upper_pending)  /* application requests in progress */
+	__u32_field(7, 0, dev_lower_pending)  /* backing device requests in progress */
+	__flg_field(8, 0, dev_upper_blocked)
+	__flg_field(9, 0, dev_lower_blocked)
+	__flg_field(10, 0, dev_al_suspended)  /* activity log suspended */
+	__u64_field(11, 0, dev_exposed_data_uuid)
+	__u64_field(12, 0, dev_current_uuid)
+	__u32_field(13, 0, dev_disk_flags)
+	__bin_field(14, 0, history_uuids, HISTORY_UUIDS * sizeof(__u64))
+)
+
+GENL_struct(DRBD_NLA_CONNECTION_STATISTICS, 21, connection_statistics,
+	__flg_field(1, 0, conn_congested)
+)
+
+GENL_struct(DRBD_NLA_PEER_DEVICE_STATISTICS, 22, peer_device_statistics,
+	__u64_field(1, 0, peer_dev_received)  /* sectors */
+	__u64_field(2, 0, peer_dev_sent)  /* sectors */
+	__u32_field(3, 0, peer_dev_pending)  /* number of requests */
+	__u32_field(4, 0, peer_dev_unacked)  /* number of requests */
+	__u64_field(5, 0, peer_dev_out_of_sync)  /* sectors */
+	__u64_field(6, 0, peer_dev_resync_failed)  /* sectors */
+	__u64_field(7, 0, peer_dev_bitmap_uuid)
+	__u32_field(9, 0, peer_dev_flags)
+)
+
+GENL_struct(DRBD_NLA_NOTIFICATION_HEADER, 23, drbd_notification_header,
+	__u32_field(1, DRBD_GENLA_F_MANDATORY, nh_type)
+)
+
+GENL_struct(DRBD_NLA_HELPER, 24, drbd_helper_info,
+	__str_field(1, DRBD_GENLA_F_MANDATORY, helper_name, 32)
+	__u32_field(2, DRBD_GENLA_F_MANDATORY, helper_status)
+)
+
 /*
  * Notifications and commands (genlmsghdr->cmd)
  */
@@ -382,3 +452,47 @@ GENL_op(DRBD_ADM_GET_TIMEOUT_TYPE, 26, GENL_doit(drbd_adm_get_timeout_type),
 	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED))
 GENL_op(DRBD_ADM_DOWN,		27, GENL_doit(drbd_adm_down),
 	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED))
+
+GENL_notification(
+	DRBD_RESOURCE_STATE, 34, events,
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_NOTIFICATION_HEADER, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_RESOURCE_INFO, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_RESOURCE_STATISTICS, DRBD_F_REQUIRED))
+
+GENL_notification(
+	DRBD_DEVICE_STATE, 35, events,
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_NOTIFICATION_HEADER, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_DEVICE_INFO, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_DEVICE_STATISTICS, DRBD_F_REQUIRED))
+
+GENL_notification(
+	DRBD_CONNECTION_STATE, 36, events,
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_NOTIFICATION_HEADER, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_CONNECTION_INFO, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_CONNECTION_STATISTICS, DRBD_F_REQUIRED))
+
+GENL_notification(
+	DRBD_PEER_DEVICE_STATE, 37, events,
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_NOTIFICATION_HEADER, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_PEER_DEVICE_INFO, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_PEER_DEVICE_STATISTICS, DRBD_F_REQUIRED))
+
+GENL_op(
+	DRBD_ADM_GET_INITIAL_STATE, 38,
+	GENL_op_init(
+	        .dumpit = drbd_adm_get_initial_state,
+	),
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_GENLA_F_MANDATORY))
+
+GENL_notification(
+	DRBD_HELPER, 40, events,
+	GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, DRBD_F_REQUIRED)
+	GENL_tla_expected(DRBD_NLA_HELPER, DRBD_F_REQUIRED))
+
+GENL_notification(
+	DRBD_INITIAL_STATE_DONE, 41, events,
+	GENL_tla_expected(DRBD_NLA_NOTIFICATION_HEADER, DRBD_F_REQUIRED))