seaweedfs/go/storage/volume.go
2015-05-08 23:44:11 -07:00

397 lines
11 KiB
Go

package storage
import (
"bytes"
"errors"
"fmt"
"io"
"os"
"path"
"sync"
"time"
"github.com/chrislusf/seaweedfs/go/glog"
)
type Volume struct {
Id VolumeId
dir string
Collection string
dataFile *os.File
nm NeedleMapper
needleMapKind NeedleMapType
readOnly bool
SuperBlock
accessLock sync.Mutex
lastModifiedTime uint64 //unix time in seconds
}
func NewVolume(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType, replicaPlacement *ReplicaPlacement, ttl *TTL) (v *Volume, e error) {
v = &Volume{dir: dirname, Collection: collection, Id: id}
v.SuperBlock = SuperBlock{ReplicaPlacement: replicaPlacement, Ttl: ttl}
v.needleMapKind = needleMapKind
e = v.load(true, true, needleMapKind)
return
}
func (v *Volume) String() string {
return fmt.Sprintf("Id:%v, dir:%s, Collection:%s, dataFile:%v, nm:%v, readOnly:%v", v.Id, v.dir, v.Collection, v.dataFile, v.nm, v.readOnly)
}
func loadVolumeWithoutIndex(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType) (v *Volume, e error) {
v = &Volume{dir: dirname, Collection: collection, Id: id}
v.SuperBlock = SuperBlock{}
v.needleMapKind = needleMapKind
e = v.load(false, false, needleMapKind)
return
}
func (v *Volume) FileName() (fileName string) {
if v.Collection == "" {
fileName = path.Join(v.dir, v.Id.String())
} else {
fileName = path.Join(v.dir, v.Collection+"_"+v.Id.String())
}
return
}
func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind NeedleMapType) error {
var e error
fileName := v.FileName()
if exists, canRead, canWrite, modifiedTime := checkFile(fileName + ".dat"); exists {
if !canRead {
return fmt.Errorf("cannot read Volume Data file %s.dat", fileName)
}
if canWrite {
v.dataFile, e = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
v.lastModifiedTime = uint64(modifiedTime.Unix())
} else {
glog.V(0).Infoln("opening " + fileName + ".dat in READONLY mode")
v.dataFile, e = os.Open(fileName + ".dat")
v.readOnly = true
}
} else {
if createDatIfMissing {
v.dataFile, e = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
} else {
return fmt.Errorf("Volume Data file %s.dat does not exist.", fileName)
}
}
if e != nil {
if !os.IsPermission(e) {
return fmt.Errorf("cannot load Volume Data %s.dat: %v", fileName, e)
}
}
if v.ReplicaPlacement == nil {
e = v.readSuperBlock()
} else {
e = v.maybeWriteSuperBlock()
}
if e == nil && alsoLoadIndex {
var indexFile *os.File
if v.readOnly {
glog.V(1).Infoln("open to read file", fileName+".idx")
if indexFile, e = os.OpenFile(fileName+".idx", os.O_RDONLY, 0644); e != nil {
return fmt.Errorf("cannot read Volume Index %s.idx: %v", fileName, e)
}
} else {
glog.V(1).Infoln("open to write file", fileName+".idx")
if indexFile, e = os.OpenFile(fileName+".idx", os.O_RDWR|os.O_CREATE, 0644); e != nil {
return fmt.Errorf("cannot write Volume Index %s.idx: %v", fileName, e)
}
}
switch needleMapKind {
case NeedleMapInMemory:
glog.V(0).Infoln("loading index file", fileName+".idx", "readonly", v.readOnly)
if v.nm, e = LoadNeedleMap(indexFile); e != nil {
glog.V(0).Infof("loading index %s error: %v", fileName+".idx", e)
}
case NeedleMapLevelDb:
glog.V(0).Infoln("loading leveldb file", fileName+".ldb")
if v.nm, e = NewLevelDbNeedleMap(fileName+".ldb", indexFile); e != nil {
glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", e)
}
case NeedleMapBoltDb:
glog.V(0).Infoln("loading boltdb file", fileName+".bdb")
if v.nm, e = NewBoltDbNeedleMap(fileName+".bdb", indexFile); e != nil {
glog.V(0).Infof("loading boltdb %s error: %v", fileName+".bdb", e)
}
}
}
return e
}
func (v *Volume) Version() Version {
return v.SuperBlock.Version()
}
func (v *Volume) Size() int64 {
stat, e := v.dataFile.Stat()
if e == nil {
return stat.Size()
}
glog.V(0).Infof("Failed to read file size %s %v", v.dataFile.Name(), e)
return -1
}
// Close cleanly shuts down this volume
func (v *Volume) Close() {
v.accessLock.Lock()
defer v.accessLock.Unlock()
v.nm.Close()
_ = v.dataFile.Close()
}
func (v *Volume) NeedToReplicate() bool {
return v.ReplicaPlacement.GetCopyCount() > 1
}
// isFileUnchanged checks whether this needle to write is same as last one.
// It requires serialized access in the same volume.
func (v *Volume) isFileUnchanged(n *Needle) bool {
nv, ok := v.nm.Get(n.Id)
if ok && nv.Offset > 0 {
oldNeedle := new(Needle)
_, err := oldNeedle.Read(v.dataFile, int64(nv.Offset)*NeedlePaddingSize, nv.Size, v.Version())
if err != nil {
glog.V(0).Infof("Failed to check updated file %v", err)
return false
}
if oldNeedle.Checksum == n.Checksum && bytes.Equal(oldNeedle.Data, n.Data) {
n.DataSize = oldNeedle.DataSize
return true
}
}
return false
}
// Destroy removes everything related to this volume
func (v *Volume) Destroy() (err error) {
if v.readOnly {
err = fmt.Errorf("%s is read-only", v.dataFile.Name())
return
}
v.Close()
err = os.Remove(v.dataFile.Name())
if err != nil {
return
}
err = v.nm.Destroy()
return
}
func (v *Volume) write(n *Needle) (size uint32, err error) {
glog.V(4).Infof("writing needle %s", NewFileIdFromNeedle(v.Id, n).String())
if v.readOnly {
err = fmt.Errorf("%s is read-only", v.dataFile.Name())
return
}
v.accessLock.Lock()
defer v.accessLock.Unlock()
if v.isFileUnchanged(n) {
size = n.DataSize
glog.V(4).Infof("needle is unchanged!")
return
}
var offset int64
if offset, err = v.dataFile.Seek(0, 2); err != nil {
glog.V(0).Infof("failed to seek the end of file: %v", err)
return
}
//ensure file writing starting from aligned positions
if offset%NeedlePaddingSize != 0 {
offset = offset + (NeedlePaddingSize - offset%NeedlePaddingSize)
if offset, err = v.dataFile.Seek(offset, 0); err != nil {
glog.V(0).Infof("failed to align in datafile %s: %v", v.dataFile.Name(), err)
return
}
}
if size, err = n.Append(v.dataFile, v.Version()); err != nil {
if e := v.dataFile.Truncate(offset); e != nil {
err = fmt.Errorf("%s\ncannot truncate %s: %v", err, v.dataFile.Name(), e)
}
return
}
nv, ok := v.nm.Get(n.Id)
if !ok || int64(nv.Offset)*NeedlePaddingSize < offset {
if err = v.nm.Put(n.Id, uint32(offset/NeedlePaddingSize), n.Size); err != nil {
glog.V(4).Infof("failed to save in needle map %d: %v", n.Id, err)
}
}
if v.lastModifiedTime < n.LastModified {
v.lastModifiedTime = n.LastModified
}
return
}
func (v *Volume) delete(n *Needle) (uint32, error) {
glog.V(4).Infof("delete needle %s", NewFileIdFromNeedle(v.Id, n).String())
if v.readOnly {
return 0, fmt.Errorf("%s is read-only", v.dataFile.Name())
}
v.accessLock.Lock()
defer v.accessLock.Unlock()
nv, ok := v.nm.Get(n.Id)
//fmt.Println("key", n.Id, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
if ok {
size := nv.Size
if err := v.nm.Delete(n.Id); err != nil {
return size, err
}
if _, err := v.dataFile.Seek(0, 2); err != nil {
return size, err
}
n.Data = nil
_, err := n.Append(v.dataFile, v.Version())
return size, err
}
return 0, nil
}
func (v *Volume) read(n *Needle) (int, error) {
nv, ok := v.nm.Get(n.Id)
if !ok || nv.Offset == 0 {
return -1, errors.New("Not Found")
}
bytesRead, err := n.Read(v.dataFile, int64(nv.Offset)*NeedlePaddingSize, nv.Size, v.Version())
if err != nil {
return bytesRead, err
}
if !n.HasTtl() {
return bytesRead, err
}
ttlMinutes := n.Ttl.Minutes()
if ttlMinutes == 0 {
return bytesRead, nil
}
if !n.HasLastModifiedDate() {
return bytesRead, nil
}
if uint64(time.Now().Unix()) < n.LastModified+uint64(ttlMinutes*60) {
return bytesRead, nil
}
return -1, errors.New("Not Found")
}
func ScanVolumeFile(dirname string, collection string, id VolumeId,
needleMapKind NeedleMapType,
visitSuperBlock func(SuperBlock) error,
readNeedleBody bool,
visitNeedle func(n *Needle, offset int64) error) (err error) {
var v *Volume
if v, err = loadVolumeWithoutIndex(dirname, collection, id, needleMapKind); err != nil {
return fmt.Errorf("Failed to load volume %d: %v", id, err)
}
if err = visitSuperBlock(v.SuperBlock); err != nil {
return fmt.Errorf("Failed to process volume %d super block: %v", id, err)
}
version := v.Version()
offset := int64(SuperBlockSize)
n, rest, e := ReadNeedleHeader(v.dataFile, version, offset)
if e != nil {
err = fmt.Errorf("cannot read needle header: %v", e)
return
}
for n != nil {
if readNeedleBody {
if err = n.ReadNeedleBody(v.dataFile, version, offset+int64(NeedleHeaderSize), rest); err != nil {
glog.V(0).Infof("cannot read needle body: %v", err)
//err = fmt.Errorf("cannot read needle body: %v", err)
//return
}
if n.DataSize >= n.Size {
// this should come from a bug reported on #87 and #93
// fixed in v0.69
// remove this whole "if" clause later, long after 0.69
oldRest, oldSize := rest, n.Size
padding := NeedlePaddingSize - ((n.Size + NeedleHeaderSize + NeedleChecksumSize) % NeedlePaddingSize)
n.Size = 0
rest = n.Size + NeedleChecksumSize + padding
if rest%NeedlePaddingSize != 0 {
rest += (NeedlePaddingSize - rest%NeedlePaddingSize)
}
glog.V(4).Infof("Adjusting n.Size %d=>0 rest:%d=>%d %+v", oldSize, oldRest, rest, n)
}
}
if err = visitNeedle(n, offset); err != nil {
glog.V(0).Infof("visit needle error: %v", err)
}
offset += int64(NeedleHeaderSize) + int64(rest)
glog.V(4).Infof("==> new entry offset %d", offset)
if n, rest, err = ReadNeedleHeader(v.dataFile, version, offset); err != nil {
if err == io.EOF {
return nil
}
return fmt.Errorf("cannot read needle header: %v", err)
}
glog.V(4).Infof("new entry needle size:%d rest:%d", n.Size, rest)
}
return
}
func (v *Volume) ContentSize() uint64 {
return v.nm.ContentSize()
}
func checkFile(filename string) (exists, canRead, canWrite bool, modTime time.Time) {
exists = true
fi, err := os.Stat(filename)
if os.IsNotExist(err) {
exists = false
return
}
if fi.Mode()&0400 != 0 {
canRead = true
}
if fi.Mode()&0200 != 0 {
canWrite = true
}
modTime = fi.ModTime()
return
}
// volume is expired if modified time + volume ttl < now
// except when volume is empty
// or when the volume does not have a ttl
// or when volumeSizeLimit is 0 when server just starts
func (v *Volume) expired(volumeSizeLimit uint64) bool {
if volumeSizeLimit == 0 {
//skip if we don't know size limit
return false
}
if v.ContentSize() == 0 {
return false
}
if v.Ttl == nil || v.Ttl.Minutes() == 0 {
return false
}
glog.V(0).Infof("now:%v lastModified:%v", time.Now().Unix(), v.lastModifiedTime)
livedMinutes := (time.Now().Unix() - int64(v.lastModifiedTime)) / 60
glog.V(0).Infof("ttl:%v lived:%v", v.Ttl, livedMinutes)
if int64(v.Ttl.Minutes()) < livedMinutes {
return true
}
return false
}
// wait either maxDelayMinutes or 10% of ttl minutes
func (v *Volume) exiredLongEnough(maxDelayMinutes uint32) bool {
if v.Ttl == nil || v.Ttl.Minutes() == 0 {
return false
}
removalDelay := v.Ttl.Minutes() / 10
if removalDelay > maxDelayMinutes {
removalDelay = maxDelayMinutes
}
if uint64(v.Ttl.Minutes()+removalDelay)*60+v.lastModifiedTime < uint64(time.Now().Unix()) {
return true
}
return false
}