gsh-digital-services/seaweedFS
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prepare for flexible super block

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This commit is contained in:
Chris Lu
2018-06-24 11:37:08 -07:00
parent b46cf2bb0e
commit 9ba335a7c4
5 changed files with 45 additions and 35 deletions
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35
weed/storage/volume_super_block.go
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@@ -9,7 +9,7 @@ import (
)
const (
SuperBlockSize = 8
_SuperBlockSize = 8
)
/*
@@ -27,11 +27,15 @@ type SuperBlock struct {
CompactRevision uint16
}
func (s *SuperBlock) BlockSize() int {
return _SuperBlockSize
}
func (s *SuperBlock) Version() Version {
return s.version
}
func (s *SuperBlock) Bytes() []byte {
header := make([]byte, SuperBlockSize)
header := make([]byte, _SuperBlockSize)
header[0] = byte(s.version)
header[1] = s.ReplicaPlacement.Byte()
s.Ttl.ToBytes(header[2:4])
@@ -59,18 +63,13 @@ func (v *Volume) maybeWriteSuperBlock() error {
}
return e
}
func (v *Volume) readSuperBlock() (err error) {
if _, err = v.dataFile.Seek(0, 0); err != nil {
return fmt.Errorf("cannot seek to the beginning of %s: %v", v.dataFile.Name(), err)
}
header := make([]byte, SuperBlockSize)
if _, e := v.dataFile.Read(header); e != nil {
return fmt.Errorf("cannot read volume %d super block: %v", v.Id, e)
}
v.SuperBlock, err = ParseSuperBlock(header)
v.SuperBlock, err = ReadSuperBlock(v.dataFile)
return err
}
func ParseSuperBlock(header []byte) (superBlock SuperBlock, err error) {
func parseSuperBlock(header []byte) (superBlock SuperBlock, err error) {
superBlock.version = Version(header[0])
if superBlock.ReplicaPlacement, err = NewReplicaPlacementFromByte(header[1]); err != nil {
err = fmt.Errorf("cannot read replica type: %s", err.Error())
@@ -79,3 +78,17 @@ func ParseSuperBlock(header []byte) (superBlock SuperBlock, err error) {
superBlock.CompactRevision = util.BytesToUint16(header[4:6])
return
}
// ReadSuperBlock reads from data file and load it into volume's super block
func ReadSuperBlock(dataFile *os.File) (superBlock SuperBlock, err error) {
if _, err = dataFile.Seek(0, 0); err != nil {
err = fmt.Errorf("cannot seek to the beginning of %s: %v", dataFile.Name(), err)
return
}
header := make([]byte, _SuperBlockSize)
if _, e := dataFile.Read(header); e != nil {
err = fmt.Errorf("cannot read volume %s super block: %v", dataFile.Name(), e)
return
}
return parseSuperBlock(header)
}