minio/cmd/erasure-healfile.go
Andreas Auernhammer 85fcee1919 erasure: simplify XL backend operations (#4649) (#4758)
This change provides new implementations of the XL backend operations:
 - create file
 - read   file
 - heal   file
Further this change adds table based tests for all three operations.

This affects also the bitrot algorithm integration. Algorithms are now
integrated in an idiomatic way (like crypto.Hash).
Fixes #4696
Fixes #4649
Fixes #4359
2017-08-14 18:08:42 -07:00

91 lines
3.0 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 "hash"
// HealFile tries to reconstruct a bitrot encoded file spread over all available disks. HealFile will read the valid parts of the file,
// reconstruct the missing data and write the reconstructed parts back to the disks.
// It will try to read the valid parts from the file under the given volume and path and tries to reconstruct the file under the given
// healVolume and healPath. The given algorithm will be used to verify the valid parts and to protect the reconstructed file.
func (s ErasureStorage) HealFile(offlineDisks []StorageAPI, volume, path string, blocksize int64, healVolume, healPath string, size int64, algorithm BitrotAlgorithm, checksums [][]byte) (f ErasureFileInfo, err error) {
if !algorithm.Available() {
return f, traceError(errBitrotHashAlgoInvalid)
}
f.Checksums = make([][]byte, len(s.disks))
hashers, verifiers := make([]hash.Hash, len(s.disks)), make([]*BitrotVerifier, len(s.disks))
for i, disk := range s.disks {
if disk == OfflineDisk {
hashers[i] = algorithm.New()
} else {
verifiers[i] = NewBitrotVerifier(algorithm, checksums[i])
f.Checksums[i] = checksums[i]
}
}
blocks := make([][]byte, len(s.disks))
chunksize := getChunkSize(blocksize, s.dataBlocks)
for offset := int64(0); offset < size; offset += blocksize {
if size < blocksize {
blocksize = size
chunksize = getChunkSize(blocksize, s.dataBlocks)
}
numReads := 0
for i, disk := range s.disks {
if disk != OfflineDisk {
if blocks[i] == nil {
blocks[i] = make([]byte, chunksize)
}
blocks[i] = blocks[i][:chunksize]
if !verifiers[i].IsVerified() {
_, err = disk.ReadFileWithVerify(volume, path, offset, blocks[i], verifiers[i])
} else {
_, err = disk.ReadFile(volume, path, offset, blocks[i])
}
if err != nil {
blocks[i] = nil
} else {
numReads++
}
if numReads == s.dataBlocks { // we have enough data to reconstruct
break
}
}
}
if err = s.ErasureDecodeDataAndParityBlocks(blocks); err != nil {
return f, err
}
for i, disk := range s.disks {
if disk != OfflineDisk {
continue
}
if err = offlineDisks[i].AppendFile(healVolume, healPath, blocks[i]); err != nil {
return f, traceError(err)
}
hashers[i].Write(blocks[i])
}
}
f.Size = size
f.Algorithm = algorithm
for i, disk := range s.disks {
if disk != OfflineDisk {
continue
}
f.Checksums[i] = hashers[i].Sum(nil)
}
return f, nil
}