1 files changed, 60 insertions, 14 deletions

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3779c8d2875..09803d0d520 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -522,6 +522,13 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
 		mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
 		break;
 
+	case DISCARD_COMPLETED_NOTSUPP:
+	case DISCARD_COMPLETED_WITH_ERROR:
+		/* I'd rather not detach from local disk just because it
+		 * failed a REQ_DISCARD. */
+		mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
+		break;
+
 	case QUEUE_FOR_NET_READ:
 		/* READ or READA, and
 		 * no local disk,
@@ -1235,6 +1242,7 @@ void do_submit(struct work_struct *ws)
 		if (list_empty(&incoming))
 			break;
 
+skip_fast_path:
 		wait_event(device->al_wait, prepare_al_transaction_nonblock(device, &incoming, &pending));
 		/* Maybe more was queued, while we prepared the transaction?
 		 * Try to stuff them into this transaction as well.
@@ -1273,6 +1281,25 @@ void do_submit(struct work_struct *ws)
 			list_del_init(&req->tl_requests);
 			drbd_send_and_submit(device, req);
 		}
+
+		/* If all currently hot activity log extents are kept busy by
+		 * incoming requests, we still must not totally starve new
+		 * requests to cold extents. In that case, prepare one request
+		 * in blocking mode. */
+		list_for_each_entry_safe(req, tmp, &incoming, tl_requests) {
+			list_del_init(&req->tl_requests);
+			req->rq_state |= RQ_IN_ACT_LOG;
+			if (!drbd_al_begin_io_prepare(device, &req->i)) {
+				/* Corresponding extent was hot after all? */
+				drbd_send_and_submit(device, req);
+			} else {
+				/* Found a request to a cold extent.
+				 * Put on "pending" list,
+				 * and try to cumulate with more. */
+				list_add(&req->tl_requests, &pending);
+				goto skip_fast_path;
+			}
+		}
 	}
 }
 
@@ -1326,23 +1353,35 @@ int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct
 	return limit;
 }
 
-static struct drbd_request *find_oldest_request(struct drbd_connection *connection)
+static void find_oldest_requests(
+		struct drbd_connection *connection,
+		struct drbd_device *device,
+		struct drbd_request **oldest_req_waiting_for_peer,
+		struct drbd_request **oldest_req_waiting_for_disk)
 {
-	/* Walk the transfer log,
-	 * and find the oldest not yet completed request */
 	struct drbd_request *r;
+	*oldest_req_waiting_for_peer = NULL;
+	*oldest_req_waiting_for_disk = NULL;
 	list_for_each_entry(r, &connection->transfer_log, tl_requests) {
-		if (atomic_read(&r->completion_ref))
-			return r;
+		const unsigned s = r->rq_state;
+		if (!*oldest_req_waiting_for_peer
+		&& ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE)))
+			*oldest_req_waiting_for_peer = r;
+
+		if (!*oldest_req_waiting_for_disk
+		&& (s & RQ_LOCAL_PENDING) && r->device == device)
+			*oldest_req_waiting_for_disk = r;
+
+		if (*oldest_req_waiting_for_peer && *oldest_req_waiting_for_disk)
+			break;
 	}
-	return NULL;
 }
 
 void request_timer_fn(unsigned long data)
 {
 	struct drbd_device *device = (struct drbd_device *) data;
 	struct drbd_connection *connection = first_peer_device(device)->connection;
-	struct drbd_request *req; /* oldest request */
+	struct drbd_request *req_disk, *req_peer; /* oldest request */
 	struct net_conf *nc;
 	unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
 	unsigned long now;
@@ -1366,8 +1405,8 @@ void request_timer_fn(unsigned long data)
 	now = jiffies;
 
 	spin_lock_irq(&device->resource->req_lock);
-	req = find_oldest_request(connection);
-	if (!req) {
+	find_oldest_requests(connection, device, &req_peer, &req_disk);
+	if (req_peer == NULL && req_disk == NULL) {
 		spin_unlock_irq(&device->resource->req_lock);
 		mod_timer(&device->request_timer, now + et);
 		return;
@@ -1389,19 +1428,26 @@ void request_timer_fn(unsigned long data)
 	 * ~198 days with 250 HZ, we have a window where the timeout would need
 	 * to expire twice (worst case) to become effective. Good enough.
 	 */
-	if (ent && req->rq_state & RQ_NET_PENDING &&
-		 time_after(now, req->start_time + ent) &&
+	if (ent && req_peer &&
+		 time_after(now, req_peer->start_time + ent) &&
 		!time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) {
 		drbd_warn(device, "Remote failed to finish a request within ko-count * timeout\n");
 		_drbd_set_state(_NS(device, conn, C_TIMEOUT), CS_VERBOSE | CS_HARD, NULL);
 	}
-	if (dt && req->rq_state & RQ_LOCAL_PENDING && req->device == device &&
-		 time_after(now, req->start_time + dt) &&
+	if (dt && req_disk &&
+		 time_after(now, req_disk->start_time + dt) &&
 		!time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) {
 		drbd_warn(device, "Local backing device failed to meet the disk-timeout\n");
 		__drbd_chk_io_error(device, DRBD_FORCE_DETACH);
 	}
-	nt = (time_after(now, req->start_time + et) ? now : req->start_time) + et;
+
+	/* Reschedule timer for the nearest not already expired timeout.
+	 * Fallback to now + min(effective network timeout, disk timeout). */
+	ent = (ent && req_peer && time_before(now, req_peer->start_time + ent))
+		? req_peer->start_time + ent : now + et;
+	dt = (dt && req_disk && time_before(now, req_disk->start_time + dt))
+		? req_disk->start_time + dt : now + et;
+	nt = time_before(ent, dt) ? ent : dt;
 	spin_unlock_irq(&connection->resource->req_lock);
 	mod_timer(&device->request_timer, nt);
 }