Chris Lu
4 years ago
2 changed files with 123 additions and 112 deletions
@ -0,0 +1,123 @@ |
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package storage |
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import ( |
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"fmt" |
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"io" |
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"time" |
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|
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"github.com/chrislusf/seaweedfs/weed/glog" |
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"github.com/chrislusf/seaweedfs/weed/storage/backend" |
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"github.com/chrislusf/seaweedfs/weed/storage/needle" |
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"github.com/chrislusf/seaweedfs/weed/storage/super_block" |
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. "github.com/chrislusf/seaweedfs/weed/storage/types" |
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) |
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|
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// read fills in Needle content by looking up n.Id from NeedleMapper
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func (v *Volume) readNeedle(n *needle.Needle, readOption *ReadOption) (int, error) { |
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v.dataFileAccessLock.RLock() |
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defer v.dataFileAccessLock.RUnlock() |
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|
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nv, ok := v.nm.Get(n.Id) |
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if !ok || nv.Offset.IsZero() { |
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return -1, ErrorNotFound |
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} |
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readSize := nv.Size |
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if readSize.IsDeleted() { |
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if readOption != nil && readOption.ReadDeleted && readSize != TombstoneFileSize { |
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glog.V(3).Infof("reading deleted %s", n.String()) |
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readSize = -readSize |
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} else { |
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return -1, ErrorDeleted |
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} |
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} |
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if readSize == 0 { |
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return 0, nil |
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} |
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err := n.ReadData(v.DataBackend, nv.Offset.ToActualOffset(), readSize, v.Version()) |
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if err == needle.ErrorSizeMismatch && OffsetSize == 4 { |
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err = n.ReadData(v.DataBackend, nv.Offset.ToActualOffset()+int64(MaxPossibleVolumeSize), readSize, v.Version()) |
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} |
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v.checkReadWriteError(err) |
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if err != nil { |
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return 0, err |
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} |
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bytesRead := len(n.Data) |
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if !n.HasTtl() { |
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return bytesRead, nil |
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} |
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ttlMinutes := n.Ttl.Minutes() |
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if ttlMinutes == 0 { |
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return bytesRead, nil |
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} |
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if !n.HasLastModifiedDate() { |
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return bytesRead, nil |
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} |
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if time.Now().Before(time.Unix(0, int64(n.AppendAtNs)).Add(time.Duration(ttlMinutes) * time.Minute)) { |
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return bytesRead, nil |
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} |
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return -1, ErrorNotFound |
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} |
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|
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type VolumeFileScanner interface { |
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VisitSuperBlock(super_block.SuperBlock) error |
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ReadNeedleBody() bool |
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VisitNeedle(n *needle.Needle, offset int64, needleHeader, needleBody []byte) error |
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} |
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func ScanVolumeFile(dirname string, collection string, id needle.VolumeId, |
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needleMapKind NeedleMapKind, |
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volumeFileScanner VolumeFileScanner) (err error) { |
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var v *Volume |
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if v, err = loadVolumeWithoutIndex(dirname, collection, id, needleMapKind); err != nil { |
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return fmt.Errorf("failed to load volume %d: %v", id, err) |
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} |
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if err = volumeFileScanner.VisitSuperBlock(v.SuperBlock); err != nil { |
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return fmt.Errorf("failed to process volume %d super block: %v", id, err) |
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} |
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defer v.Close() |
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version := v.Version() |
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offset := int64(v.SuperBlock.BlockSize()) |
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return ScanVolumeFileFrom(version, v.DataBackend, offset, volumeFileScanner) |
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} |
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func ScanVolumeFileFrom(version needle.Version, datBackend backend.BackendStorageFile, offset int64, volumeFileScanner VolumeFileScanner) (err error) { |
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n, nh, rest, e := needle.ReadNeedleHeader(datBackend, version, offset) |
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if e != nil { |
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if e == io.EOF { |
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return nil |
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} |
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return fmt.Errorf("cannot read %s at offset %d: %v", datBackend.Name(), offset, e) |
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} |
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for n != nil { |
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var needleBody []byte |
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if volumeFileScanner.ReadNeedleBody() { |
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// println("needle", n.Id.String(), "offset", offset, "size", n.Size, "rest", rest)
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if needleBody, err = n.ReadNeedleBody(datBackend, version, offset+NeedleHeaderSize, rest); err != nil { |
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glog.V(0).Infof("cannot read needle head [%d, %d) body [%d, %d) body length %d: %v", offset, offset+NeedleHeaderSize, offset+NeedleHeaderSize, offset+NeedleHeaderSize+rest, rest, err) |
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// err = fmt.Errorf("cannot read needle body: %v", err)
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// return
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} |
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} |
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err := volumeFileScanner.VisitNeedle(n, offset, nh, needleBody) |
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if err == io.EOF { |
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return nil |
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} |
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if err != nil { |
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glog.V(0).Infof("visit needle error: %v", err) |
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return fmt.Errorf("visit needle error: %v", err) |
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} |
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offset += NeedleHeaderSize + rest |
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glog.V(4).Infof("==> new entry offset %d", offset) |
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if n, nh, rest, err = needle.ReadNeedleHeader(datBackend, version, offset); err != nil { |
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if err == io.EOF { |
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return nil |
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} |
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return fmt.Errorf("cannot read needle header at offset %d: %v", offset, err) |
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} |
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glog.V(4).Infof("new entry needle size:%d rest:%d", n.Size, rest) |
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} |
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return nil |
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} |
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