mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2024-11-29 05:49:03 +08:00
406 lines
11 KiB
Go
406 lines
11 KiB
Go
package storage
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import (
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"bytes"
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"code.google.com/p/weed-fs/go/glog"
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"errors"
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"fmt"
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"io"
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"os"
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"path"
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"sync"
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)
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const (
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SuperBlockSize = 8
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)
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type SuperBlock struct {
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Version Version
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ReplicaType ReplicationType
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}
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func (s *SuperBlock) Bytes() []byte {
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header := make([]byte, SuperBlockSize)
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header[0] = byte(s.Version)
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header[1] = s.ReplicaType.Byte()
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return header
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}
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type Volume struct {
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Id VolumeId
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dir string
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dataFile *os.File
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nm NeedleMapper
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readOnly bool
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SuperBlock
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accessLock sync.Mutex
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}
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func NewVolume(dirname string, id VolumeId, replicationType ReplicationType) (v *Volume, e error) {
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v = &Volume{dir: dirname, Id: id}
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v.SuperBlock = SuperBlock{ReplicaType: replicationType}
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e = v.load(true)
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return
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}
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func loadVolumeWithoutIndex(dirname string, id VolumeId) (v *Volume, e error) {
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v = &Volume{dir: dirname, Id: id}
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v.SuperBlock = SuperBlock{ReplicaType: CopyNil}
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e = v.load(false)
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return
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}
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func (v *Volume) load(alsoLoadIndex bool) error {
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var e error
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fileName := path.Join(v.dir, v.Id.String())
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v.dataFile, e = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
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if e != nil {
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if !os.IsPermission(e) {
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return fmt.Errorf("cannot create Volume Data %s.dat: %s", fileName, e.Error())
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}
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if v.dataFile, e = os.Open(fileName + ".dat"); e != nil {
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return fmt.Errorf("cannot open Volume Data %s.dat: %s", fileName, e.Error())
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}
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glog.V(0).Infoln("opening " + fileName + ".dat in READONLY mode")
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v.readOnly = true
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}
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if v.ReplicaType == CopyNil {
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e = v.readSuperBlock()
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} else {
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e = v.maybeWriteSuperBlock()
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}
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if e == nil && alsoLoadIndex {
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var indexFile *os.File
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if v.readOnly {
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glog.V(2).Infoln("opening file", fileName+".idx")
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if indexFile, e = os.Open(fileName + ".idx"); e != nil && !os.IsNotExist(e) {
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return fmt.Errorf("cannot open index file %s.idx: %s", fileName, e.Error())
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}
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if indexFile != nil {
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glog.V(2).Infoln("check file", fileName+".cdb")
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if _, err := os.Stat(fileName + ".cdb"); os.IsNotExist(err) {
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glog.V(0).Infof("converting %s.idx to %s.cdb", fileName, fileName)
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if e = ConvertIndexToCdb(fileName+".cdb", indexFile); e != nil {
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glog.V(0).Infof("error converting %s.idx to %s.cdb: %s", fileName, e.Error())
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} else {
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indexFile.Close()
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indexFile = nil
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}
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}
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}
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glog.V(2).Infoln("open file", fileName+".cdb")
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if v.nm, e = OpenCdbMap(fileName + ".cdb"); e != nil {
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if os.IsNotExist(e) {
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glog.V(0).Infof("Failed to read cdb file :%s, fall back to normal readonly mode.", fileName)
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} else {
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glog.V(0).Infof("%s.cdb open errro:%s", fileName, e.Error())
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return e
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}
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}
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}
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if v.readOnly {
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glog.V(1).Infoln("open to read file", fileName+".idx")
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indexFile, e = os.OpenFile(fileName+".idx", os.O_RDONLY, 0644)
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if e != nil {
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return fmt.Errorf("cannot read Volume Data %s.dat: %s", fileName, e.Error())
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}
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} else {
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glog.V(1).Infoln("open to write file", fileName+".idx")
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indexFile, e = os.OpenFile(fileName+".idx", os.O_RDWR|os.O_CREATE, 0644)
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if e != nil {
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return fmt.Errorf("cannot create Volume Data %s.dat: %s", fileName, e.Error())
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}
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}
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glog.V(0).Infoln("loading file", fileName+".idx", "readonly", v.readOnly)
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if v.nm, e = LoadNeedleMap(indexFile); e != nil {
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glog.V(0).Infoln("loading error:", e)
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}
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}
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return e
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}
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func (v *Volume) Version() Version {
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return v.SuperBlock.Version
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}
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func (v *Volume) Size() int64 {
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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stat, e := v.dataFile.Stat()
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if e == nil {
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return stat.Size()
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}
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glog.V(0).Infof("Failed to read file size %s %s", v.dataFile.Name(), e.Error())
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return -1
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}
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func (v *Volume) Close() {
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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v.nm.Close()
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_ = v.dataFile.Close()
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}
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func (v *Volume) maybeWriteSuperBlock() error {
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stat, e := v.dataFile.Stat()
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if e != nil {
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glog.V(0).Infof("failed to stat datafile %s: %s", v.dataFile, e.Error())
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return e
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}
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if stat.Size() == 0 {
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v.SuperBlock.Version = CurrentVersion
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_, e = v.dataFile.Write(v.SuperBlock.Bytes())
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if e != nil && os.IsPermission(e) {
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//read-only, but zero length - recreate it!
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if v.dataFile, e = os.Create(v.dataFile.Name()); e == nil {
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if _, e = v.dataFile.Write(v.SuperBlock.Bytes()); e == nil {
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v.readOnly = false
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}
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}
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}
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}
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return e
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}
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func (v *Volume) readSuperBlock() (err error) {
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if _, err = v.dataFile.Seek(0, 0); err != nil {
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return fmt.Errorf("cannot seek to the beginning of %s: %s", v.dataFile, err)
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}
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header := make([]byte, SuperBlockSize)
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if _, e := v.dataFile.Read(header); e != nil {
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return fmt.Errorf("cannot read superblock: %s", e)
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}
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v.SuperBlock, err = ParseSuperBlock(header)
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return err
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}
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func ParseSuperBlock(header []byte) (superBlock SuperBlock, err error) {
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superBlock.Version = Version(header[0])
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if superBlock.ReplicaType, err = NewReplicationTypeFromByte(header[1]); err != nil {
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err = fmt.Errorf("cannot read replica type: %s", err)
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}
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return
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}
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func (v *Volume) NeedToReplicate() bool {
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return v.ReplicaType.GetCopyCount() > 1
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}
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func (v *Volume) isFileUnchanged(n *Needle) bool {
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nv, ok := v.nm.Get(n.Id)
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if ok && nv.Offset > 0 {
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if _, err := v.dataFile.Seek(int64(nv.Offset)*NeedlePaddingSize, 0); err != nil {
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return false
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}
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oldNeedle := new(Needle)
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oldNeedle.Read(v.dataFile, nv.Size, v.Version())
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if oldNeedle.Checksum == n.Checksum && bytes.Equal(oldNeedle.Data, n.Data) {
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n.Size = oldNeedle.Size
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return true
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}
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}
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return false
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}
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func (v *Volume) write(n *Needle) (size uint32, err error) {
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if v.readOnly {
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err = fmt.Errorf("%s is read-only", v.dataFile)
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return
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}
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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if v.isFileUnchanged(n) {
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size = n.Size
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return
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}
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var offset int64
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if offset, err = v.dataFile.Seek(0, 2); err != nil {
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return
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}
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//ensure file writing starting from aligned positions
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if offset%NeedlePaddingSize != 0 {
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offset = offset + (NeedlePaddingSize - offset%NeedlePaddingSize)
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if offset, err = v.dataFile.Seek(offset, 0); err != nil {
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return
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}
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}
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if size, err = n.Append(v.dataFile, v.Version()); err != nil {
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if e := v.dataFile.Truncate(offset); e != nil {
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err = fmt.Errorf("%s\ncannot truncate %s: %s", err, v.dataFile, e)
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}
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return
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}
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nv, ok := v.nm.Get(n.Id)
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if !ok || int64(nv.Offset)*NeedlePaddingSize < offset {
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_, err = v.nm.Put(n.Id, uint32(offset/NeedlePaddingSize), n.Size)
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}
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return
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}
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func (v *Volume) delete(n *Needle) (uint32, error) {
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if v.readOnly {
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return 0, fmt.Errorf("%s is read-only", v.dataFile)
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}
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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nv, ok := v.nm.Get(n.Id)
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//fmt.Println("key", n.Id, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
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if ok {
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size := nv.Size
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if err := v.nm.Delete(n.Id); err != nil {
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return size, err
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}
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if _, err := v.dataFile.Seek(0, 2); err != nil {
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return size, err
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}
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n.Data = make([]byte, 0)
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_, err := n.Append(v.dataFile, v.Version())
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return size, err
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}
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return 0, nil
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}
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func (v *Volume) read(n *Needle) (int, error) {
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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nv, ok := v.nm.Get(n.Id)
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if ok && nv.Offset > 0 {
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if _, err := v.dataFile.Seek(int64(nv.Offset)*NeedlePaddingSize, 0); err != nil {
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return -1, err
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}
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return n.Read(v.dataFile, nv.Size, v.Version())
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}
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return -1, errors.New("Not Found")
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}
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func (v *Volume) garbageLevel() float64 {
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return float64(v.nm.DeletedSize()) / float64(v.ContentSize())
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}
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func (v *Volume) compact() error {
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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filePath := path.Join(v.dir, v.Id.String())
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return v.copyDataAndGenerateIndexFile(filePath+".cpd", filePath+".cpx")
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}
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func (v *Volume) commitCompact() error {
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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_ = v.dataFile.Close()
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var e error
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if e = os.Rename(path.Join(v.dir, v.Id.String()+".cpd"), path.Join(v.dir, v.Id.String()+".dat")); e != nil {
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return e
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}
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if e = os.Rename(path.Join(v.dir, v.Id.String()+".cpx"), path.Join(v.dir, v.Id.String()+".idx")); e != nil {
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return e
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}
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if e = v.load(true); e != nil {
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return e
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}
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return nil
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}
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func (v *Volume) freeze() error {
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if v.readOnly {
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return nil
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}
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nm, ok := v.nm.(*NeedleMap)
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if !ok {
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return nil
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}
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v.accessLock.Lock()
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defer v.accessLock.Unlock()
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bn, _ := nakeFilename(v.dataFile.Name())
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cdbFn := bn + ".cdb"
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glog.V(0).Infof("converting %s to %s", nm.indexFile.Name(), cdbFn)
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err := DumpNeedleMapToCdb(cdbFn, nm)
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if err != nil {
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return err
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}
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if v.nm, err = OpenCdbMap(cdbFn); err != nil {
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return err
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}
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nm.indexFile.Close()
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os.Remove(nm.indexFile.Name())
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v.readOnly = true
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return nil
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}
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func ScanVolumeFile(dirname string, id VolumeId,
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visitSuperBlock func(SuperBlock) error,
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visitNeedle func(n *Needle, offset uint32) error) (err error) {
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var v *Volume
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if v, err = loadVolumeWithoutIndex(dirname, id); err != nil {
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return
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}
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if err = visitSuperBlock(v.SuperBlock); err != nil {
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return
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}
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version := v.Version()
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offset := uint32(SuperBlockSize)
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n, rest, e := ReadNeedleHeader(v.dataFile, version)
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if e != nil {
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err = fmt.Errorf("cannot read needle header: %s", e)
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return
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}
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for n != nil {
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if err = n.ReadNeedleBody(v.dataFile, version, rest); err != nil {
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err = fmt.Errorf("cannot read needle body: %s", err)
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return
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}
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if err = visitNeedle(n, offset); err != nil {
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return
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}
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offset += NeedleHeaderSize + rest
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if n, rest, err = ReadNeedleHeader(v.dataFile, version); 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: %s", err)
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}
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}
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return
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}
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func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string) (err error) {
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var (
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dst, idx *os.File
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)
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if dst, err = os.OpenFile(dstName, os.O_WRONLY|os.O_CREATE, 0644); err != nil {
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return
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}
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defer dst.Close()
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if idx, err = os.OpenFile(idxName, os.O_WRONLY|os.O_CREATE, 0644); err != nil {
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return
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}
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defer idx.Close()
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nm := NewNeedleMap(idx)
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new_offset := uint32(SuperBlockSize)
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err = ScanVolumeFile(v.dir, v.Id, func(superBlock SuperBlock) error {
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_, err = dst.Write(superBlock.Bytes())
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return err
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}, func(n *Needle, offset uint32) error {
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nv, ok := v.nm.Get(n.Id)
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//glog.V(0).Infoln("file size is", n.Size, "rest", rest)
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if ok && nv.Offset*NeedlePaddingSize == offset {
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if nv.Size > 0 {
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if _, err = nm.Put(n.Id, new_offset/NeedlePaddingSize, n.Size); err != nil {
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return fmt.Errorf("cannot put needle: %s", err)
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}
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if _, err = n.Append(dst, v.Version()); err != nil {
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return fmt.Errorf("cannot append needle: %s", err)
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}
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new_offset += n.DiskSize()
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//glog.V(0).Infoln("saving key", n.Id, "volume offset", old_offset, "=>", new_offset, "data_size", n.Size, "rest", rest)
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}
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}
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return nil
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})
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return
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}
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func (v *Volume) ContentSize() uint64 {
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return v.nm.ContentSize()
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}
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