85fcee1919
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
108 lines
3 KiB
Go
108 lines
3 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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"bytes"
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"io"
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"github.com/klauspost/reedsolomon"
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)
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// getDataBlockLen - get length of data blocks from encoded blocks.
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func getDataBlockLen(enBlocks [][]byte, dataBlocks int) int {
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size := 0
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// Figure out the data block length.
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for _, block := range enBlocks[:dataBlocks] {
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size += len(block)
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}
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return size
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}
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// Writes all the data blocks from encoded blocks until requested
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// outSize length. Provides a way to skip bytes until the offset.
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func writeDataBlocks(dst io.Writer, enBlocks [][]byte, dataBlocks int, offset int64, length int64) (int64, error) {
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// Offset and out size cannot be negative.
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if offset < 0 || length < 0 {
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return 0, traceError(errUnexpected)
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}
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// Do we have enough blocks?
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if len(enBlocks) < dataBlocks {
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return 0, traceError(reedsolomon.ErrTooFewShards)
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}
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// Do we have enough data?
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if int64(getDataBlockLen(enBlocks, dataBlocks)) < length {
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return 0, traceError(reedsolomon.ErrShortData)
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}
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// Counter to decrement total left to write.
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write := length
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// Counter to increment total written.
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var totalWritten int64
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// Write all data blocks to dst.
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for _, block := range enBlocks[:dataBlocks] {
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// Skip blocks until we have reached our offset.
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if offset >= int64(len(block)) {
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// Decrement offset.
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offset -= int64(len(block))
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continue
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} else {
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// Skip until offset.
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block = block[offset:]
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// Reset the offset for next iteration to read everything
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// from subsequent blocks.
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offset = 0
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}
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// We have written all the blocks, write the last remaining block.
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if write < int64(len(block)) {
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n, err := io.Copy(dst, bytes.NewReader(block[:write]))
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if err != nil {
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return 0, traceError(err)
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}
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totalWritten += n
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break
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}
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// Copy the block.
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n, err := io.Copy(dst, bytes.NewReader(block))
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if err != nil {
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return 0, traceError(err)
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}
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// Decrement output size.
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write -= n
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// Increment written.
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totalWritten += n
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}
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// Success.
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return totalWritten, nil
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}
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// chunkSize is roughly BlockSize/DataBlocks.
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// chunkSize is calculated such that chunkSize*DataBlocks accommodates BlockSize bytes.
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// So chunkSize*DataBlocks can be slightly larger than BlockSize if BlockSize is not divisible by
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// DataBlocks. The extra space will have 0-padding.
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func getChunkSize(blockSize int64, dataBlocks int) int64 {
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return (blockSize + int64(dataBlocks) - 1) / int64(dataBlocks)
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}
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