read in case cross chunks

weed/filer2/stream.go

@@ -98,18 +98,20 @@ func NewChunkStreamReaderFromFiler(masterClient *wdclient.MasterClient, chunks [
 	}
 }
 
-
 func (c *ChunkStreamReader) Read(p []byte) (n int, err error) {
+	for n < len(p) {
 		if c.isBufferEmpty() {
 			if c.chunkIndex >= len(c.chunkViews) {
-			return 0, io.EOF
+				return n, io.EOF
 			}
 			chunkView := c.chunkViews[c.chunkIndex]
 			c.fetchChunkToBuffer(chunkView)
 			c.chunkIndex++
 		}
-	n = copy(p, c.buffer[c.bufferPos:])
+		t := copy(p[n:], c.buffer[c.bufferPos:])
-	c.bufferPos += n
+		c.bufferPos += t
+		n += t
+	}
 	return
 }