168 lines
4.8 KiB
Go
168 lines
4.8 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 main
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import (
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"encoding/hex"
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"hash"
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"io"
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"sync"
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"github.com/klauspost/reedsolomon"
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)
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// erasureCreateFile - writes an entire stream by erasure coding to
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// all the disks, writes also calculate individual block's checksum
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// for future bit-rot protection.
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func erasureCreateFile(disks []StorageAPI, volume string, path string, partName string, data io.Reader, eInfos []erasureInfo, writeQuorum int) (newEInfos []erasureInfo, size int64, err error) {
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// Just pick one eInfo.
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eInfo := pickValidErasureInfo(eInfos)
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// Allocated blockSized buffer for reading.
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buf := make([]byte, eInfo.BlockSize)
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hashWriters := newHashWriters(len(disks))
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// Read until io.EOF, erasure codes data and writes to all disks.
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for {
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var blocks [][]byte
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n, rErr := io.ReadFull(data, buf)
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// FIXME: this is a bug in Golang, n == 0 and err ==
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// io.ErrUnexpectedEOF for io.ReadFull function.
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if n == 0 && rErr == io.ErrUnexpectedEOF {
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return nil, 0, rErr
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}
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if rErr == io.EOF {
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// We have reached EOF on the first byte read, io.Reader
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// must be 0bytes, we don't need to erasure code
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// data. Will create a 0byte file instead.
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if size == 0 {
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blocks = make([][]byte, len(disks))
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rErr = appendFile(disks, volume, path, blocks, eInfo.Distribution, hashWriters, writeQuorum)
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if rErr != nil {
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return nil, 0, rErr
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}
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} // else we have reached EOF after few reads, no need to
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// add an additional 0bytes at the end.
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break
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}
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if rErr != nil && rErr != io.ErrUnexpectedEOF {
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return nil, 0, rErr
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}
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if n > 0 {
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// Returns encoded blocks.
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var enErr error
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blocks, enErr = encodeData(buf[0:n], eInfo.DataBlocks, eInfo.ParityBlocks)
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if enErr != nil {
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return nil, 0, enErr
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}
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// Write to all disks.
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if err = appendFile(disks, volume, path, blocks, eInfo.Distribution, hashWriters, writeQuorum); err != nil {
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return nil, 0, err
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}
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size += int64(n)
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}
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}
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// Save the checksums.
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checkSums := make([]checkSumInfo, len(disks))
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for index := range disks {
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blockIndex := eInfo.Distribution[index] - 1
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checkSums[blockIndex] = checkSumInfo{
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Name: partName,
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Algorithm: "blake2b",
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Hash: hex.EncodeToString(hashWriters[blockIndex].Sum(nil)),
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}
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}
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// Erasure info update for checksum for each disks.
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newEInfos = make([]erasureInfo, len(disks))
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for index, eInfo := range eInfos {
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if eInfo.IsValid() {
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blockIndex := eInfo.Distribution[index] - 1
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newEInfos[index] = eInfo
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newEInfos[index].Checksum = append(newEInfos[index].Checksum, checkSums[blockIndex])
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}
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}
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// Return newEInfos.
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return newEInfos, size, nil
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}
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// encodeData - encodes incoming data buffer into
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// dataBlocks+parityBlocks returns a 2 dimensional byte array.
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func encodeData(dataBuffer []byte, dataBlocks, parityBlocks int) ([][]byte, error) {
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rs, err := reedsolomon.New(dataBlocks, parityBlocks)
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if err != nil {
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return nil, err
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}
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// Split the input buffer into data and parity blocks.
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var blocks [][]byte
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blocks, err = rs.Split(dataBuffer)
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if err != nil {
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return nil, err
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}
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// Encode parity blocks using data blocks.
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err = rs.Encode(blocks)
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if err != nil {
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return nil, err
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}
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// Return encoded blocks.
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return blocks, nil
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}
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// appendFile - append data buffer at path.
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func appendFile(disks []StorageAPI, volume, path string, enBlocks [][]byte, distribution []int, hashWriters []hash.Hash, writeQuorum int) (err error) {
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var wg = &sync.WaitGroup{}
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var wErrs = make([]error, len(disks))
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// Write encoded data to quorum disks in parallel.
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for index, disk := range disks {
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if disk == nil {
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continue
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}
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wg.Add(1)
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// Write encoded data in routine.
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go func(index int, disk StorageAPI) {
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defer wg.Done()
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// Pick the block from the distribution.
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blockIndex := distribution[index] - 1
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wErr := disk.AppendFile(volume, path, enBlocks[blockIndex])
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if wErr != nil {
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wErrs[index] = wErr
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return
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}
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// Calculate hash for each blocks.
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hashWriters[blockIndex].Write(enBlocks[blockIndex])
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// Successfully wrote.
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wErrs[index] = nil
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}(index, disk)
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}
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// Wait for all the appends to finish.
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wg.Wait()
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// Do we have write quorum?.
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if !isDiskQuorum(wErrs, writeQuorum) {
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return toObjectErr(errXLWriteQuorum, volume, path)
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}
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return nil
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}
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