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https://github.com/seaweedfs/seaweedfs.git
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203 lines
5.5 KiB
Go
203 lines
5.5 KiB
Go
package erasure_coding
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import (
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"fmt"
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"io"
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"os"
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"github.com/chrislusf/seaweedfs/weed/glog"
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"github.com/chrislusf/seaweedfs/weed/storage/idx"
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"github.com/chrislusf/seaweedfs/weed/storage/needle_map"
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"github.com/chrislusf/seaweedfs/weed/storage/types"
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"github.com/klauspost/reedsolomon"
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)
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const (
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DataShardsCount = 10
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ParityShardsCount = 4
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ErasureCodingLargeBlockSize = 1024 * 1024 * 1024 // 1GB
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ErasureCodingSmallBlockSize = 1024 * 1024 // 1MB
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)
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// WriteSortedEcxFile generates .ecx file from existing .idx file
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// all keys are sorted in ascending order
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func WriteSortedEcxFile(baseFileName string) (e error) {
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cm, err := readCompactMap(baseFileName)
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if err != nil {
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return fmt.Errorf("readCompactMap: %v", err)
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}
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ecxFile, err := os.OpenFile(baseFileName+".ecx", os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0644)
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if err != nil {
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return fmt.Errorf("failed to open dat file: %v", err)
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}
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defer ecxFile.Close()
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err = cm.AscendingVisit(func(value needle_map.NeedleValue) error {
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bytes := value.ToBytes()
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_, writeErr := ecxFile.Write(bytes)
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return writeErr
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})
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if err != nil {
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return fmt.Errorf("failed to open dat file: %v", err)
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}
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return nil
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}
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// WriteEcFiles generates .ec01 ~ .ec14 files
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func WriteEcFiles(baseFileName string) error {
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return generateEcFiles(baseFileName, 256*1024, ErasureCodingLargeBlockSize, ErasureCodingSmallBlockSize)
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}
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func ToExt(ecIndex int) string {
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return fmt.Sprintf(".ec%02d", ecIndex)
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}
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func generateEcFiles(baseFileName string, bufferSize int, largeBlockSize int64, smallBlockSize int64) error {
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file, err := os.OpenFile(baseFileName+".dat", os.O_RDONLY, 0)
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if err != nil {
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return fmt.Errorf("failed to open dat file: %v", err)
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}
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defer file.Close()
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fi, err := file.Stat()
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if err != nil {
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return fmt.Errorf("failed to stat dat file: %v", err)
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}
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err = encodeDatFile(fi.Size(), err, baseFileName, bufferSize, largeBlockSize, file, smallBlockSize)
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if err != nil {
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return fmt.Errorf("encodeDatFile: %v", err)
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}
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return nil
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}
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func encodeData(file *os.File, enc reedsolomon.Encoder, startOffset, blockSize int64, buffers [][]byte, outputs []*os.File) error {
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bufferSize := int64(len(buffers[0]))
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batchCount := blockSize / bufferSize
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if blockSize%bufferSize != 0 {
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glog.Fatalf("unexpected block size %d buffer size %d", blockSize, bufferSize)
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}
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for b := int64(0); b < batchCount; b++ {
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err := encodeDataOneBatch(file, enc, startOffset+b*bufferSize, blockSize, buffers, outputs)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func openEcFiles(baseFileName string, forRead bool) (files []*os.File, err error) {
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for i := 0; i < DataShardsCount+ParityShardsCount; i++ {
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fname := baseFileName + ToExt(i+1)
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openOption := os.O_TRUNC | os.O_CREATE | os.O_WRONLY
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if forRead {
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openOption = os.O_RDONLY
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}
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f, err := os.OpenFile(fname, openOption, 0644)
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if err != nil {
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return files, fmt.Errorf("failed to open file %s: %v", fname, err)
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}
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files = append(files, f)
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}
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return
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}
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func closeEcFiles(files []*os.File) {
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for _, f := range files {
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if f != nil {
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f.Close()
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}
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}
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}
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func encodeDataOneBatch(file *os.File, enc reedsolomon.Encoder, startOffset, blockSize int64, buffers [][]byte, outputs []*os.File) error {
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// read data into buffers
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for i := 0; i < DataShardsCount; i++ {
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n, err := file.ReadAt(buffers[i], startOffset+blockSize*int64(i))
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if err != nil {
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if err != io.EOF {
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return err
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}
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}
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if n < len(buffers[i]) {
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for t := len(buffers[i]) - 1; t >= n; t-- {
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buffers[i][t] = 0
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}
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}
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}
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err := enc.Encode(buffers)
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if err != nil {
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return err
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}
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for i := 0; i < DataShardsCount+ParityShardsCount; i++ {
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_, err := outputs[i].Write(buffers[i])
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if err != nil {
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return err
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}
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}
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return nil
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}
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func encodeDatFile(remainingSize int64, err error, baseFileName string, bufferSize int, largeBlockSize int64, file *os.File, smallBlockSize int64) error {
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var processedSize int64
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enc, err := reedsolomon.New(DataShardsCount, ParityShardsCount)
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if err != nil {
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return fmt.Errorf("failed to create encoder: %v", err)
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}
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buffers := make([][]byte, DataShardsCount+ParityShardsCount)
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outputs, err := openEcFiles(baseFileName, false)
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defer closeEcFiles(outputs)
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if err != nil {
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return fmt.Errorf("failed to open dat file: %v", err)
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}
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for i, _ := range buffers {
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buffers[i] = make([]byte, bufferSize)
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}
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for remainingSize > largeBlockSize*DataShardsCount {
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err = encodeData(file, enc, processedSize, largeBlockSize, buffers, outputs)
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if err != nil {
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return fmt.Errorf("failed to encode large chunk data: %v", err)
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}
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remainingSize -= largeBlockSize * DataShardsCount
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processedSize += largeBlockSize * DataShardsCount
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}
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for remainingSize > 0 {
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encodeData(file, enc, processedSize, smallBlockSize, buffers, outputs)
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if err != nil {
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return fmt.Errorf("failed to encode small chunk data: %v", err)
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}
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remainingSize -= smallBlockSize * DataShardsCount
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processedSize += smallBlockSize * DataShardsCount
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}
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return nil
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}
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func readCompactMap(baseFileName string) (*needle_map.CompactMap, error) {
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indexFile, err := os.OpenFile(baseFileName+".idx", os.O_RDONLY, 0644)
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if err != nil {
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return nil, fmt.Errorf("cannot read Volume Index %s.idx: %v", baseFileName, err)
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}
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defer indexFile.Close()
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cm := needle_map.NewCompactMap()
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err = idx.WalkIndexFile(indexFile, func(key types.NeedleId, offset types.Offset, size uint32) error {
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if !offset.IsZero() && size != types.TombstoneFileSize {
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cm.Set(key, offset, size)
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} else {
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cm.Delete(key)
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}
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return nil
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})
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return cm, err
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}
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