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44 lines
1.3 KiB
44 lines
1.3 KiB
package super_block
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import (
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"fmt"
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"github.com/golang/protobuf/proto"
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"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
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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/util"
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)
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// ReadSuperBlock reads from data file and load it into volume's super block
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func ReadSuperBlock(datBackend backend.BackendStorageFile) (superBlock SuperBlock, err error) {
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header := make([]byte, SuperBlockSize)
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if _, e := datBackend.ReadAt(header, 0); e != nil {
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err = fmt.Errorf("cannot read volume %s super block: %v", datBackend.Name(), e)
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return
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}
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superBlock.Version = needle.Version(header[0])
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if superBlock.ReplicaPlacement, err = NewReplicaPlacementFromByte(header[1]); err != nil {
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err = fmt.Errorf("cannot read replica type: %s", err.Error())
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return
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}
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superBlock.Ttl = needle.LoadTTLFromBytes(header[2:4])
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superBlock.CompactionRevision = util.BytesToUint16(header[4:6])
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superBlock.ExtraSize = util.BytesToUint16(header[6:8])
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if superBlock.ExtraSize > 0 {
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// read more
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extraData := make([]byte, int(superBlock.ExtraSize))
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superBlock.Extra = &master_pb.SuperBlockExtra{}
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err = proto.Unmarshal(extraData, superBlock.Extra)
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if err != nil {
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err = fmt.Errorf("cannot read volume %s super block extra: %v", datBackend.Name(), err)
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return
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}
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}
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return
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}
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