From f16ddcb62287998ff1bb0e087867276648cf29bc Mon Sep 17 00:00:00 2001
From: Arkadiy Paronyan <arkady.paronyan@gmail.com>
Date: Sat, 26 Jan 2019 00:09:56 +0100
Subject: [PATCH] Only request justifications from available peers (#1586)

---
 substrate/core/network/src/sync.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/substrate/core/network/src/sync.rs b/substrate/core/network/src/sync.rs
index cf93b020b4..629e8e3d1b 100644
--- a/substrate/core/network/src/sync.rs
+++ b/substrate/core/network/src/sync.rs
@@ -92,8 +92,8 @@ impl<B: BlockT> PendingJustifications<B> {
 		}
 
 		let mut available_peers = peers.iter().filter_map(|(peer, sync)| {
-			// don't request to any peers that already have pending requests
-			if self.peer_requests.contains_key(&peer) {
+			// don't request to any peers that already have pending requests or are unavailable
+			if sync.state != PeerSyncState::Available || self.peer_requests.contains_key(&peer) {
 				None
 			} else {
 				Some((*peer, sync.best_number))
@@ -152,6 +152,7 @@ impl<B: BlockT> PendingJustifications<B> {
 				.expect("peer was is taken from available_peers; available_peers is a subset of peers; qed")
 				.state = PeerSyncState::DownloadingJustification(request.0);
 
+			trace!(target: "sync", "Requesting justification for block #{} from {}", request.0, peer);
 			let request = message::generic::BlockRequest {
 				id: 0,
 				fields: message::BlockAttributes::JUSTIFICATION,