file.go | 4 ++--

diff --git a/file.go b/file.go
index f57cd7af8a35b8491040fbd51e3e4fba88d611b1..720e4fb510e37396bd715b8afee172cb03616754 100644
--- a/file.go
+++ b/file.go
@@ -54,6 +54,8 @@ }
 
 // Returns the state of pieces in this file.
 func (f *File) State() (ret []FilePieceState) {
+	f.t.cl.mu.RLock()
+	defer f.t.cl.mu.RUnlock()
 	pieceSize := int64(f.t.usualPieceSize())
 	off := f.offset % pieceSize
 	remaining := f.length
@@ -65,9 +67,7 @@ 		len1 := pieceSize - off
 		if len1 > remaining {
 			len1 = remaining
 		}
-		f.t.cl.mu.RLock()
 		ps := f.t.pieceState(i)
-		f.t.cl.mu.RUnlock()
 		ret = append(ret, FilePieceState{len1, ps})
 		off = 0
 		remaining -= len1