Cleanup blockmap on update (fixes #889)

internal/files/blockmap.go

@@ -90,6 +90,17 @@ func (m *BlockMap) Update(files []protocol.FileInfo) error {
 	return m.db.Write(batch, nil)
 }
 
+// Discard block map state, removing the given files
+func (m *BlockMap) Discard(files []protocol.FileInfo) error {
+	batch := new(leveldb.Batch)
+	for _, file := range files {
+		for _, block := range file.Blocks {
+			batch.Delete(m.blockKey(block.Hash, file.Name))
+		}
+	}
+	return m.db.Write(batch, nil)
+}
+
 // Drop block map, removing all entries related to this block map from the db.
 func (m *BlockMap) Drop() error {
 	batch := new(leveldb.Batch)

internal/files/set.go

@@ -111,12 +111,22 @@ func (s *Set) Update(device protocol.DeviceID, fs []protocol.FileInfo) {
 	normalizeFilenames(fs)
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
+	if device == protocol.LocalDeviceID {
+		discards := make([]protocol.FileInfo, 0, len(fs))
+		updates := make([]protocol.FileInfo, 0, len(fs))
+		for _, newFile := range fs {
+			existingFile := ldbGet(s.db, []byte(s.folder), device[:], []byte(newFile.Name))
+			if existingFile.Version <= newFile.Version {
+				discards = append(discards, existingFile)
+				updates = append(updates, newFile)
+			}
+		}
+		s.blockmap.Discard(discards)
+		s.blockmap.Update(updates)
+	}
 	if lv := ldbUpdate(s.db, []byte(s.folder), device[:], fs); lv > s.localVersion[device] {
 		s.localVersion[device] = lv
 	}
-	if device == protocol.LocalDeviceID {
-		s.blockmap.Update(fs)
-	}
 }
 
 func (s *Set) WithNeed(device protocol.DeviceID, fn fileIterator) {