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85 lines
2.5 KiB
Go
85 lines
2.5 KiB
Go
/*
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* Minio Cloud Storage, (C) 2016 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 "encoding/hex"
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// Heals the erasure coded file. reedsolomon.Reconstruct() is used to reconstruct the missing parts.
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func erasureHealFile(latestDisks []StorageAPI, outDatedDisks []StorageAPI, volume, path, healBucket, healPath string, size int64, blockSize int64, dataBlocks int, parityBlocks int, algo string) (checkSums []string, err error) {
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var offset int64
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remainingSize := size
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// Hash for bitrot protection.
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hashWriters := newHashWriters(len(outDatedDisks), bitRotAlgo)
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for remainingSize > 0 {
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curBlockSize := blockSize
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if remainingSize < curBlockSize {
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curBlockSize = remainingSize
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}
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// Calculate the block size that needs to be read from each disk.
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curEncBlockSize := getChunkSize(curBlockSize, dataBlocks)
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// Memory for reading data from disks and reconstructing missing data using erasure coding.
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enBlocks := make([][]byte, len(latestDisks))
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// Read data from the latest disks.
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// FIXME: no need to read from all the disks. dataBlocks+1 is enough.
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for index, disk := range latestDisks {
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if disk == nil {
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continue
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}
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enBlocks[index] = make([]byte, curEncBlockSize)
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_, err := disk.ReadFile(volume, path, offset, enBlocks[index])
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if err != nil {
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enBlocks[index] = nil
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}
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}
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// Reconstruct missing data.
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err := decodeData(enBlocks, dataBlocks, parityBlocks)
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if err != nil {
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return nil, err
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}
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// Write to the healPath file.
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for index, disk := range outDatedDisks {
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if disk == nil {
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continue
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}
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err := disk.AppendFile(healBucket, healPath, enBlocks[index])
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if err != nil {
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return nil, traceError(err)
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}
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hashWriters[index].Write(enBlocks[index])
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}
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remainingSize -= curBlockSize
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offset += curEncBlockSize
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}
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// Checksums for the bit rot.
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checkSums = make([]string, len(outDatedDisks))
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for index, disk := range outDatedDisks {
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if disk == nil {
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continue
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}
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checkSums[index] = hex.EncodeToString(hashWriters[index].Sum(nil))
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}
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return checkSums, nil
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}
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