From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 30 Mar 2017 10:38:44 +0000 (+1100)
Subject: storage: Fix race condition in mapPieceCompletion
X-Git-Tag: v1.0.0~475
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=65a7c3daa71c2ca8d6ebccfd02e4831ae448e609;p=btrtrc.git

storage: Fix race condition in mapPieceCompletion
---

diff --git a/storage/completion.go b/storage/completion.go
index 15fcc249..78043510 100644
--- a/storage/completion.go
+++ b/storage/completion.go
@@ -6,7 +6,7 @@ import (
 	"github.com/anacrolix/torrent/metainfo"
 )
 
-// Implementations track the completion of pieces.
+// Implementations track the completion of pieces. It must be concurrent-safe.
 type pieceCompletion interface {
 	Get(metainfo.PieceKey) (bool, error)
 	Set(metainfo.PieceKey, bool) error
diff --git a/storage/completion_piece_map.go b/storage/completion_piece_map.go
index cca13245..f4b4e285 100644
--- a/storage/completion_piece_map.go
+++ b/storage/completion_piece_map.go
@@ -1,21 +1,27 @@
 package storage
 
 import (
+	"sync"
+
 	"github.com/anacrolix/torrent/metainfo"
 )
 
 type mapPieceCompletion struct {
-	m map[metainfo.PieceKey]struct{}
+	mu sync.Mutex
+	m  map[metainfo.PieceKey]struct{}
 }
 
 func (mapPieceCompletion) Close() error { return nil }
 
 func (me *mapPieceCompletion) Get(pk metainfo.PieceKey) (bool, error) {
+	me.mu.Lock()
 	_, ok := me.m[pk]
+	me.mu.Unlock()
 	return ok, nil
 }
 
 func (me *mapPieceCompletion) Set(pk metainfo.PieceKey, b bool) error {
+	me.mu.Lock()
 	if b {
 		if me.m == nil {
 			me.m = make(map[metainfo.PieceKey]struct{})
@@ -24,5 +30,6 @@ func (me *mapPieceCompletion) Set(pk metainfo.PieceKey, b bool) error {
 	} else {
 		delete(me.m, pk)
 	}
+	me.mu.Unlock()
 	return nil
 }