100 lines
2.9 KiB
Go
100 lines
2.9 KiB
Go
/*
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* Minio Cloud Storage, (C) 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package cmd
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import (
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"context"
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"github.com/klauspost/reedsolomon"
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"github.com/minio/minio/cmd/logger"
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)
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// OfflineDisk represents an unavailable disk.
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var OfflineDisk StorageAPI // zero value is nil
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// ErasureStorage - erasure encoding details.
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type ErasureStorage struct {
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erasure reedsolomon.Encoder
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dataBlocks, parityBlocks int
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blockSize int64
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}
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// NewErasureStorage creates a new ErasureStorage.
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func NewErasureStorage(ctx context.Context, dataBlocks, parityBlocks int, blockSize int64) (s ErasureStorage, err error) {
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shardsize := int(ceilFrac(blockSize, int64(dataBlocks)))
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erasure, err := reedsolomon.New(dataBlocks, parityBlocks, reedsolomon.WithAutoGoroutines(shardsize))
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if err != nil {
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logger.LogIf(ctx, err)
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return s, err
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}
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s = ErasureStorage{
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erasure: erasure,
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dataBlocks: dataBlocks,
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parityBlocks: parityBlocks,
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blockSize: blockSize,
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}
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return
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}
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// ErasureEncode encodes the given data and returns the erasure-coded data.
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// It returns an error if the erasure coding failed.
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func (s *ErasureStorage) ErasureEncode(ctx context.Context, data []byte) ([][]byte, error) {
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if len(data) == 0 {
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return make([][]byte, s.dataBlocks+s.parityBlocks), nil
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}
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encoded, err := s.erasure.Split(data)
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if err != nil {
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logger.LogIf(ctx, err)
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return nil, err
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}
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if err = s.erasure.Encode(encoded); err != nil {
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logger.LogIf(ctx, err)
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return nil, err
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}
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return encoded, nil
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}
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// ErasureDecodeDataBlocks decodes the given erasure-coded data.
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// It only decodes the data blocks but does not verify them.
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// It returns an error if the decoding failed.
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func (s *ErasureStorage) ErasureDecodeDataBlocks(data [][]byte) error {
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needsReconstruction := false
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for _, b := range data[:s.dataBlocks] {
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if b == nil {
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needsReconstruction = true
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break
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}
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}
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if !needsReconstruction {
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return nil
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}
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if err := s.erasure.ReconstructData(data); err != nil {
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return err
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}
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return nil
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}
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// ErasureDecodeDataAndParityBlocks decodes the given erasure-coded data and verifies it.
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// It returns an error if the decoding failed.
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func (s *ErasureStorage) ErasureDecodeDataAndParityBlocks(ctx context.Context, data [][]byte) error {
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if err := s.erasure.Reconstruct(data); err != nil {
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logger.LogIf(ctx, err)
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return err
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}
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return nil
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}
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