You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
69 lines
1.8 KiB
69 lines
1.8 KiB
package super_block
|
|
|
|
import (
|
|
"google.golang.org/protobuf/proto"
|
|
|
|
"github.com/seaweedfs/seaweedfs/weed/glog"
|
|
"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
|
|
"github.com/seaweedfs/seaweedfs/weed/storage/needle"
|
|
"github.com/seaweedfs/seaweedfs/weed/util"
|
|
)
|
|
|
|
const (
|
|
SuperBlockSize = 8
|
|
)
|
|
|
|
/*
|
|
* Super block currently has 8 bytes allocated for each volume.
|
|
* Byte 0: version, 1 or 2
|
|
* Byte 1: Replica Placement strategy, 000, 001, 002, 010, etc
|
|
* Byte 2 and byte 3: Time to live. See TTL for definition
|
|
* Byte 4 and byte 5: The number of times the volume has been compacted.
|
|
* Rest bytes: Reserved
|
|
*/
|
|
type SuperBlock struct {
|
|
Version needle.Version
|
|
ReplicaPlacement *ReplicaPlacement
|
|
Ttl *needle.TTL
|
|
CompactionRevision uint16
|
|
Extra *master_pb.SuperBlockExtra
|
|
ExtraSize uint16
|
|
}
|
|
|
|
func (s *SuperBlock) BlockSize() int {
|
|
switch s.Version {
|
|
case needle.Version2, needle.Version3:
|
|
return SuperBlockSize + int(s.ExtraSize)
|
|
}
|
|
return SuperBlockSize
|
|
}
|
|
|
|
func (s *SuperBlock) Bytes() []byte {
|
|
header := make([]byte, SuperBlockSize)
|
|
header[0] = byte(s.Version)
|
|
header[1] = s.ReplicaPlacement.Byte()
|
|
s.Ttl.ToBytes(header[2:4])
|
|
util.Uint16toBytes(header[4:6], s.CompactionRevision)
|
|
|
|
if s.Extra != nil {
|
|
extraData, err := proto.Marshal(s.Extra)
|
|
if err != nil {
|
|
glog.Fatalf("cannot marshal super block extra %+v: %v", s.Extra, err)
|
|
}
|
|
extraSize := len(extraData)
|
|
if extraSize > 256*256-2 {
|
|
// reserve a couple of bits for future extension
|
|
glog.Fatalf("super block extra size is %d bigger than %d", extraSize, 256*256-2)
|
|
}
|
|
s.ExtraSize = uint16(extraSize)
|
|
util.Uint16toBytes(header[6:8], s.ExtraSize)
|
|
|
|
header = append(header, extraData...)
|
|
}
|
|
|
|
return header
|
|
}
|
|
|
|
func (s *SuperBlock) Initialized() bool {
|
|
return s.ReplicaPlacement != nil && s.Ttl != nil
|
|
}
|