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minio/cmd/erasure-healfile.go

91 lines
3.0 KiB

/*
* 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
}