1 files changed, 20 insertions, 12 deletions
diff --git a/weed/filer/stream.go b/weed/filer/stream.go
index 3859f9a67..503e6b23f 100644
--- a/weed/filer/stream.go
+++ b/weed/filer/stream.go
@@ -91,6 +91,7 @@ func ReadAll(masterClient *wdclient.MasterClient, chunks []*filer_pb.FileChunk)
 type ChunkStreamReader struct {
 	chunkViews         []*ChunkView
 	totalSize          int64
+	logicOffset        int64
 	buffer             []byte
 	bufferOffset       int64
 	bufferPos          int
@@ -137,8 +138,7 @@ func NewChunkStreamReader(filerClient filer_pb.FilerClient, chunks []*filer_pb.F
 }
 
 func (c *ChunkStreamReader) ReadAt(p []byte, off int64) (n int, err error) {
-	_, err = c.Seek(off, io.SeekStart)
-	if err != nil {
+	if err = c.prepareBufferFor(c.logicOffset); err != nil {
 		return
 	}
 	return c.Read(p)
@@ -151,12 +151,15 @@ func (c *ChunkStreamReader) Read(p []byte) (n int, err error) {
 				return n, io.EOF
 			}
 			chunkView := c.chunkViews[c.nextChunkViewIndex]
-			c.fetchChunkToBuffer(chunkView)
+			if err = c.fetchChunkToBuffer(chunkView); err != nil {
+				return
+			}
 			c.nextChunkViewIndex++
 		}
 		t := copy(p[n:], c.buffer[c.bufferPos:])
 		c.bufferPos += t
 		n += t
+		c.logicOffset += int64(t)
 	}
 	return
 }
@@ -171,19 +174,26 @@ func (c *ChunkStreamReader) Seek(offset int64, whence int) (int64, error) {
 	switch whence {
 	case io.SeekStart:
 	case io.SeekCurrent:
-		offset += c.bufferOffset + int64(c.bufferPos)
+		offset += c.logicOffset
 	case io.SeekEnd:
 		offset = c.totalSize + offset
 	}
 	if offset > c.totalSize {
 		err = io.ErrUnexpectedEOF
+	} else {
+		c.logicOffset = offset
 	}
 
+	return offset, err
+
+}
+
+func (c *ChunkStreamReader) prepareBufferFor(offset int64) (err error) {
 	// stay in the same chunk
 	if !c.isBufferEmpty() {
 		if c.bufferOffset <= offset && offset < c.bufferOffset+int64(len(c.buffer)) {
 			c.bufferPos = int(offset - c.bufferOffset)
-			return offset, nil
+			return nil
 		}
 	}
 
@@ -192,23 +202,21 @@ func (c *ChunkStreamReader) Seek(offset int64, whence int) (int64, error) {
 		return c.chunkViews[i].LogicOffset <= offset
 	})
 	if currentChunkIndex == len(c.chunkViews) {
-		return 0, io.EOF
+		return io.EOF
 	}
 
 	// positioning within the new chunk
 	chunk := c.chunkViews[currentChunkIndex]
 	if chunk.LogicOffset <= offset && offset < chunk.LogicOffset+int64(chunk.Size) {
 		if c.isBufferEmpty() || c.bufferOffset != chunk.LogicOffset {
-			c.fetchChunkToBuffer(chunk)
+			if err = c.fetchChunkToBuffer(chunk); err != nil {
+				return
+			}
 			c.nextChunkViewIndex = currentChunkIndex + 1
 		}
 		c.bufferPos = int(offset - c.bufferOffset)
-	} else {
-		return 0, io.ErrUnexpectedEOF
 	}
-
-	return offset, err
-
+	return
 }
 
 func (c *ChunkStreamReader) fetchChunkToBuffer(chunkView *ChunkView) error {