Merge pull request #161 from libp2p/fix/races

fix: fix some race conditions in the ds address book

pstoreds/addr_book.go

@@ -299,7 +299,16 @@ func (ab *dsAddrBook) ConsumePeerRecord(recordEnvelope *record.Envelope, ttl tim
 
 func (ab *dsAddrBook) latestPeerRecordSeq(p peer.ID) uint64 {
 	pr, err := ab.loadRecord(p, true, false)
-	if err != nil || len(pr.Addrs) == 0 || pr.CertifiedRecord == nil || len(pr.CertifiedRecord.Raw) == 0 {
+	if err != nil {
+		// We ignore the error because we don't want to fail storing a new record in this
+		// case.
+		log.Errorw("unable to load record", "peer", p, "error", err)
+		return 0
+	}
+	pr.RLock()
+	defer pr.RUnlock()
+
+	if len(pr.Addrs) == 0 || pr.CertifiedRecord == nil || len(pr.CertifiedRecord.Raw) == 0 {
 		return 0
 	}
 	return pr.CertifiedRecord.Seq
@@ -552,13 +561,13 @@ func (ab *dsAddrBook) deleteAddrs(p peer.ID, addrs []ma.Multiaddr) (err error) {
 		return fmt.Errorf("failed to load peerstore entry for peer %v while deleting addrs, err: %v", p, err)
 	}
 
+	pr.Lock()
+	defer pr.Unlock()
+
 	if pr.Addrs == nil {
 		return nil
 	}
 
-	pr.Lock()
-	defer pr.Unlock()
-
 	pr.Addrs = deleteInPlace(pr.Addrs, addrs)
 
 	pr.dirty = true