minio/cmd/erasure-healfile.go
Frank Wessels fffe4ac7e6 Prevent unnecessary verification of parity blocks while reading (#4683)
* Prevent unnecessary verification of parity blocks while reading erasure
  coded file.
* Update klauspost/reedsolomon and just only reconstruct data blocks while
  reading (prevent unnecessary parity block reconstruction)
* Remove Verification of (all) reconstructed Data and Parity blocks since
  in our case we are protected by bit rot protection. And even if the
  verification would fail (essentially impossible) there is no way to
  definitively say whether the data is still correct or not, so this call
  make no sense for our use case.
2017-08-11 18:25:46 -07:00

87 lines
2.6 KiB
Go

/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import "encoding/hex"
// Heals the erasure coded file. reedsolomon.Reconstruct() is used to reconstruct the missing parts.
func erasureHealFile(latestDisks []StorageAPI, outDatedDisks []StorageAPI, volume, path, healBucket, healPath string,
size, blockSize int64, dataBlocks, parityBlocks int, algo HashAlgo) (checkSums []string, err error) {
var offset int64
remainingSize := size
// Hash for bitrot protection.
hashWriters := newHashWriters(len(outDatedDisks), bitRotAlgo)
for remainingSize > 0 {
curBlockSize := blockSize
if remainingSize < curBlockSize {
curBlockSize = remainingSize
}
// Calculate the block size that needs to be read from each disk.
curEncBlockSize := getChunkSize(curBlockSize, dataBlocks)
// Memory for reading data from disks and reconstructing missing data using erasure coding.
enBlocks := make([][]byte, len(latestDisks))
// Read data from the latest disks.
// FIXME: no need to read from all the disks. dataBlocks+1 is enough.
for index, disk := range latestDisks {
if disk == nil {
continue
}
enBlocks[index] = make([]byte, curEncBlockSize)
_, err := disk.ReadFile(volume, path, offset, enBlocks[index])
if err != nil {
enBlocks[index] = nil
}
}
// Reconstruct any missing data and parity blocks.
err := decodeDataAndParity(enBlocks, dataBlocks, parityBlocks)
if err != nil {
return nil, err
}
// Write to the healPath file.
for index, disk := range outDatedDisks {
if disk == nil {
continue
}
err := disk.AppendFile(healBucket, healPath, enBlocks[index])
if err != nil {
return nil, traceError(err)
}
hashWriters[index].Write(enBlocks[index])
}
remainingSize -= curBlockSize
offset += curEncBlockSize
}
// Checksums for the bit rot.
checkSums = make([]string, len(outDatedDisks))
for index, disk := range outDatedDisks {
if disk == nil {
continue
}
checkSums[index] = hex.EncodeToString(hashWriters[index].Sum(nil))
}
return checkSums, nil
}