This change removes the ReadFileWithVerify function from the StorageAPI. The ReadFile was basically a redirection to ReadFileWithVerify. This change removes the redirection and moves the logic of ReadFileWithVerify directly into ReadFile. This removes a lot of unnecessary code in all StorageAPI implementations. Fixes #4946 * review: fix doc and typos
153 lines
4.5 KiB
Go
153 lines
4.5 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 (
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"hash"
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)
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// HealFile tries to reconstruct an erasure-coded file spread over all
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// available disks. HealFile will read the valid parts of the file,
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// reconstruct the missing data and write the reconstructed parts back
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// to `staleDisks`.
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//
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// `staleDisks` is a slice of disks where each non-nil entry has stale
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// or no data, and so will be healed.
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//
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// It is required that `s.disks` have a (read-quorum) majority of
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// disks with valid data for healing to work.
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//
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// In addition, `staleDisks` and `s.disks` must have the same ordering
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// of disks w.r.t. erasure coding of the object.
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//
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// The function will try to read the valid parts from the file under
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// the given volume and path and tries to reconstruct the file under
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// the given healVolume and healPath (on staleDisks). The given
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// algorithm will be used to verify the valid parts and to protect the
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// reconstructed file.
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//
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// It returns bitrot checksums for the non-nil staleDisks.
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func (s ErasureStorage) HealFile(staleDisks []StorageAPI, volume, path string,
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blocksize int64, healVolume, healPath string, size int64,
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algorithm BitrotAlgorithm, checksums [][]byte) (f ErasureFileInfo,
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err error) {
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if !algorithm.Available() {
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return f, traceError(errBitrotHashAlgoInvalid)
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}
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// Initialization
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f.Checksums = make([][]byte, len(s.disks))
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hashers := make([]hash.Hash, len(s.disks))
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verifiers := make([]*BitrotVerifier, len(s.disks))
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for i, disk := range s.disks {
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switch {
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case staleDisks[i] != nil:
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hashers[i] = algorithm.New()
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case disk == nil:
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// disregard unavailable disk
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continue
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default:
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verifiers[i] = NewBitrotVerifier(algorithm, checksums[i])
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f.Checksums[i] = checksums[i]
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}
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}
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// Scan part files on disk, block-by-block reconstruct it and
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// write to stale disks.
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chunksize := getChunkSize(blocksize, s.dataBlocks)
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var chunkOffset, blockOffset int64
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for ; blockOffset < size; blockOffset += blocksize {
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// last iteration may have less than blocksize data
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// left, so chunksize needs to be recomputed.
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if size < blockOffset+blocksize {
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blocksize = size - blockOffset
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chunksize = getChunkSize(blocksize, s.dataBlocks)
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}
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// read a chunk from each disk, until we have
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// `s.dataBlocks` number of chunks set to non-nil in
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// `blocks`
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blocks := make([][]byte, len(s.disks))
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var buffer []byte
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numReads := 0
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for i, disk := range s.disks {
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// skip reading from unavailable or stale disks
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if disk == nil || staleDisks[i] != nil {
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continue
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}
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// allocate buffer only when needed - when
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// reads fail, the buffer can be reused
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if int64(len(buffer)) != chunksize {
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buffer = make([]byte, chunksize)
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}
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_, err = disk.ReadFile(volume, path, chunkOffset, buffer, verifiers[i])
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if err != nil {
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// LOG FIXME: add a conditional log
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// for read failures, once per-disk
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// per-function-invocation.
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continue
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}
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// read was successful, so set the buffer as
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// blocks[i], and reset buffer to nil to force
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// allocation on next iteration
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blocks[i], buffer = buffer, nil
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numReads++
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if numReads == s.dataBlocks {
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// we have enough data to reconstruct
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break
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}
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}
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// advance the chunk offset to prepare for next loop
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// iteration
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chunkOffset += chunksize
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// reconstruct data - this computes all data and parity shards
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if err = s.ErasureDecodeDataAndParityBlocks(blocks); err != nil {
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return f, err
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}
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// write computed shards as chunks on file in each
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// stale disk
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for i, disk := range staleDisks {
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if disk == nil {
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continue
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}
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err = disk.AppendFile(healVolume, healPath, blocks[i])
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if err != nil {
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return f, traceError(err)
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}
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hashers[i].Write(blocks[i])
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}
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}
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// copy computed file hashes into output variable
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f.Size = size
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f.Algorithm = algorithm
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for i, disk := range staleDisks {
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if disk == nil {
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continue
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}
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f.Checksums[i] = hashers[i].Sum(nil)
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}
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return f, nil
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}
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