package filer import ( "context" "fmt" "io" "math/rand" "sync" "github.com/seaweedfs/seaweedfs/weed/glog" "github.com/seaweedfs/seaweedfs/weed/pb/filer_pb" "github.com/seaweedfs/seaweedfs/weed/util" "github.com/seaweedfs/seaweedfs/weed/wdclient" ) type ChunkReadAt struct { masterClient *wdclient.MasterClient chunkViews *IntervalList[*ChunkView] fileSize int64 readerCache *ReaderCache readerPattern *ReaderPattern lastChunkFid string } var _ = io.ReaderAt(&ChunkReadAt{}) var _ = io.Closer(&ChunkReadAt{}) func LookupFn(filerClient filer_pb.FilerClient) wdclient.LookupFileIdFunctionType { vidCache := make(map[string]*filer_pb.Locations) var vicCacheLock sync.RWMutex return func(fileId string) (targetUrls []string, err error) { vid := VolumeId(fileId) vicCacheLock.RLock() locations, found := vidCache[vid] vicCacheLock.RUnlock() if !found { util.Retry("lookup volume "+vid, func() error { err = filerClient.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error { resp, err := client.LookupVolume(context.Background(), &filer_pb.LookupVolumeRequest{ VolumeIds: []string{vid}, }) if err != nil { return err } locations = resp.LocationsMap[vid] if locations == nil || len(locations.Locations) == 0 { glog.V(0).Infof("failed to locate %s", fileId) return fmt.Errorf("failed to locate %s", fileId) } vicCacheLock.Lock() vidCache[vid] = locations vicCacheLock.Unlock() return nil }) return err }) } if err != nil { return nil, err } fcDataCenter := filerClient.GetDataCenter() var sameDcTargetUrls, otherTargetUrls []string for _, loc := range locations.Locations { volumeServerAddress := filerClient.AdjustedUrl(loc) targetUrl := fmt.Sprintf("http://%s/%s", volumeServerAddress, fileId) if fcDataCenter == "" || fcDataCenter != loc.DataCenter { otherTargetUrls = append(otherTargetUrls, targetUrl) } else { sameDcTargetUrls = append(sameDcTargetUrls, targetUrl) } } rand.Shuffle(len(sameDcTargetUrls), func(i, j int) { sameDcTargetUrls[i], sameDcTargetUrls[j] = sameDcTargetUrls[j], sameDcTargetUrls[i] }) rand.Shuffle(len(otherTargetUrls), func(i, j int) { otherTargetUrls[i], otherTargetUrls[j] = otherTargetUrls[j], otherTargetUrls[i] }) // Prefer same data center targetUrls = append(sameDcTargetUrls, otherTargetUrls...) return } } func NewChunkReaderAtFromClient(readerCache *ReaderCache, chunkViews *IntervalList[*ChunkView], fileSize int64) *ChunkReadAt { return &ChunkReadAt{ chunkViews: chunkViews, fileSize: fileSize, readerCache: readerCache, readerPattern: NewReaderPattern(), } } func (c *ChunkReadAt) Close() error { c.readerCache.destroy() return nil } func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) { c.readerPattern.MonitorReadAt(offset, len(p)) c.chunkViews.Lock.RLock() defer c.chunkViews.Lock.RUnlock() // glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews)) n, _, err = c.doReadAt(p, offset) return } func (c *ChunkReadAt) ReadAtWithTime(p []byte, offset int64) (n int, ts int64, err error) { c.readerPattern.MonitorReadAt(offset, len(p)) c.chunkViews.Lock.RLock() defer c.chunkViews.Lock.RUnlock() // glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews)) return c.doReadAt(p, offset) } func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, ts int64, err error) { startOffset, remaining := offset, int64(len(p)) var nextChunks *Interval[*ChunkView] for x := c.chunkViews.Front(); x != nil; x = x.Next { chunk := x.Value if remaining <= 0 { break } if x.Next != nil { nextChunks = x.Next } if startOffset < chunk.ViewOffset { gap := chunk.ViewOffset - startOffset glog.V(4).Infof("zero [%d,%d)", startOffset, chunk.ViewOffset) n += zero(p, startOffset-offset, gap) startOffset, remaining = chunk.ViewOffset, remaining-gap if remaining <= 0 { break } } // fmt.Printf(">>> doReadAt [%d,%d), chunk[%d,%d)\n", offset, offset+int64(len(p)), chunk.ViewOffset, chunk.ViewOffset+int64(chunk.ViewSize)) chunkStart, chunkStop := max(chunk.ViewOffset, startOffset), min(chunk.ViewOffset+int64(chunk.ViewSize), startOffset+remaining) if chunkStart >= chunkStop { continue } // glog.V(4).Infof("read [%d,%d), %d/%d chunk %s [%d,%d)", chunkStart, chunkStop, i, len(c.chunkViews), chunk.FileId, chunk.ViewOffset-chunk.Offset, chunk.ViewOffset-chunk.Offset+int64(chunk.ViewSize)) bufferOffset := chunkStart - chunk.ViewOffset + chunk.OffsetInChunk ts = chunk.ModifiedTsNs copied, err := c.readChunkSliceAt(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], chunk, nextChunks, uint64(bufferOffset)) if err != nil { glog.Errorf("fetching chunk %+v: %v\n", chunk, err) return copied, ts, err } n += copied startOffset, remaining = startOffset+int64(copied), remaining-int64(copied) } // glog.V(4).Infof("doReadAt [%d,%d), n:%v, err:%v", offset, offset+int64(len(p)), n, err) // zero the remaining bytes if a gap exists at the end of the last chunk (or a fully sparse file) if err == nil && remaining > 0 { var delta int64 if c.fileSize > startOffset { delta = min(remaining, c.fileSize-startOffset) startOffset -= offset } else { delta = remaining startOffset = max(startOffset-offset, startOffset-remaining-offset) } glog.V(4).Infof("zero2 [%d,%d) of file size %d bytes", startOffset, startOffset+delta, c.fileSize) n += zero(p, startOffset, delta) } if err == nil && offset+int64(len(p)) >= c.fileSize { err = io.EOF } // fmt.Printf("~~~ filled %d, err: %v\n\n", n, err) return } func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, nextChunkViews *Interval[*ChunkView], offset uint64) (n int, err error) { if c.readerPattern.IsRandomMode() { n, err := c.readerCache.chunkCache.ReadChunkAt(buffer, chunkView.FileId, offset) if n > 0 { return n, err } return fetchChunkRange(buffer, c.readerCache.lookupFileIdFn, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset)) } n, err = c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), chunkView.ViewOffset == 0) if c.lastChunkFid != chunkView.FileId { if chunkView.OffsetInChunk == 0 { // start of a new chunk if c.lastChunkFid != "" { c.readerCache.UnCache(c.lastChunkFid) } if nextChunkViews != nil { c.readerCache.MaybeCache(nextChunkViews) // just read the next chunk if at the very beginning } } } c.lastChunkFid = chunkView.FileId return } func zero(buffer []byte, start, length int64) int { end := min(start+length, int64(len(buffer))) start = max(start, 0) // zero the bytes for o := start; o < end; o++ { buffer[o] = 0 } return int(end - start) }