|
|
|
/*
|
|
|
|
* 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 main
|
|
|
|
|
|
|
|
import (
|
|
|
|
"errors"
|
|
|
|
"fmt"
|
|
|
|
"io"
|
|
|
|
slashpath "path"
|
|
|
|
"strconv"
|
|
|
|
)
|
|
|
|
|
|
|
|
// checkBlockSize return the size of a single block.
|
|
|
|
// The first non-zero size is returned,
|
|
|
|
// or 0 if all blocks are size 0.
|
|
|
|
func checkBlockSize(blocks [][]byte) int {
|
|
|
|
for _, block := range blocks {
|
|
|
|
if len(block) != 0 {
|
|
|
|
return len(block)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 0
|
|
|
|
}
|
|
|
|
|
|
|
|
// calculate the blockSize based on input length and total number of
|
|
|
|
// data blocks.
|
|
|
|
func getEncodedBlockLen(inputLen, dataBlocks int) (curBlockSize int) {
|
|
|
|
curBlockSize = (inputLen + dataBlocks - 1) / dataBlocks
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Returns slice of disks needed for ReadFile operation:
|
|
|
|
// - slice returing readable disks.
|
|
|
|
// - file size
|
|
|
|
// - error if any.
|
|
|
|
func (xl XL) getReadableDisks(volume, path string) ([]StorageAPI, int64, error) {
|
|
|
|
partsMetadata, errs := xl.getPartsMetadata(volume, path)
|
|
|
|
highestVersion := int64(0)
|
|
|
|
versions := make([]int64, len(xl.storageDisks))
|
|
|
|
quorumDisks := make([]StorageAPI, len(xl.storageDisks))
|
|
|
|
fileSize := int64(0)
|
|
|
|
for index, metadata := range partsMetadata {
|
|
|
|
if errs[index] == nil {
|
|
|
|
if versionStr, ok := metadata["file.version"]; ok {
|
|
|
|
// Convert string to integer.
|
|
|
|
version, err := strconv.ParseInt(versionStr, 10, 64)
|
|
|
|
if err != nil {
|
|
|
|
// Unexpected, return error.
|
|
|
|
return nil, 0, err
|
|
|
|
}
|
|
|
|
if version > highestVersion {
|
|
|
|
highestVersion = version
|
|
|
|
}
|
|
|
|
versions[index] = version
|
|
|
|
} else {
|
|
|
|
versions[index] = 0
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
versions[index] = -1
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
quorumCount := 0
|
|
|
|
for index, version := range versions {
|
|
|
|
if version == highestVersion {
|
|
|
|
quorumDisks[index] = xl.storageDisks[index]
|
|
|
|
quorumCount++
|
|
|
|
} else {
|
|
|
|
quorumDisks[index] = nil
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if quorumCount < xl.readQuorum {
|
|
|
|
return nil, 0, errReadQuorum
|
|
|
|
}
|
|
|
|
|
|
|
|
for index, disk := range quorumDisks {
|
|
|
|
if disk == nil {
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
if sizeStr, ok := partsMetadata[index]["file.size"]; ok {
|
|
|
|
var err error
|
|
|
|
fileSize, err = strconv.ParseInt(sizeStr, 10, 64)
|
|
|
|
if err != nil {
|
|
|
|
return nil, 0, err
|
|
|
|
}
|
|
|
|
break
|
|
|
|
} else {
|
|
|
|
return nil, 0, errors.New("Missing 'file.size' in meta data.")
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return quorumDisks, fileSize, nil
|
|
|
|
}
|
|
|
|
|
|
|
|
// ReadFile - read file
|
|
|
|
func (xl XL) ReadFile(volume, path string, offset int64) (io.ReadCloser, error) {
|
|
|
|
// Input validation.
|
|
|
|
if !isValidVolname(volume) {
|
|
|
|
return nil, errInvalidArgument
|
|
|
|
}
|
|
|
|
if !isValidPath(path) {
|
|
|
|
return nil, errInvalidArgument
|
|
|
|
}
|
|
|
|
|
|
|
|
// Acquire a read lock.
|
|
|
|
readLock := true
|
|
|
|
xl.lockNS(volume, path, readLock)
|
|
|
|
defer xl.unlockNS(volume, path, readLock)
|
|
|
|
|
|
|
|
quorumDisks, fileSize, err := xl.getReadableDisks(volume, path)
|
|
|
|
if err != nil {
|
|
|
|
return nil, err
|
|
|
|
}
|
|
|
|
|
|
|
|
readers := make([]io.ReadCloser, len(xl.storageDisks))
|
|
|
|
for index, disk := range quorumDisks {
|
|
|
|
if disk == nil {
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
erasurePart := slashpath.Join(path, fmt.Sprintf("part.%d", index))
|
|
|
|
// If disk.ReadFile returns error and we don't have read quorum it will be taken care as
|
|
|
|
// ReedSolomon.Reconstruct() will fail later.
|
|
|
|
var reader io.ReadCloser
|
|
|
|
if reader, err = disk.ReadFile(volume, erasurePart, offset); err == nil {
|
|
|
|
readers[index] = reader
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Initialize pipe.
|
|
|
|
pipeReader, pipeWriter := io.Pipe()
|
|
|
|
go func() {
|
|
|
|
var totalLeft = fileSize
|
|
|
|
// Read until the totalLeft.
|
|
|
|
for totalLeft > 0 {
|
|
|
|
// Figure out the right blockSize as it was encoded before.
|
|
|
|
var curBlockSize int
|
|
|
|
if erasureBlockSize < totalLeft {
|
|
|
|
curBlockSize = erasureBlockSize
|
|
|
|
} else {
|
|
|
|
curBlockSize = int(totalLeft)
|
|
|
|
}
|
|
|
|
// Calculate the current encoded block size.
|
|
|
|
curEncBlockSize := getEncodedBlockLen(curBlockSize, xl.DataBlocks)
|
|
|
|
enBlocks := make([][]byte, len(xl.storageDisks))
|
|
|
|
// Loop through all readers and read.
|
|
|
|
for index, reader := range readers {
|
|
|
|
// Initialize shard slice and fill the data from each parts.
|
|
|
|
enBlocks[index] = make([]byte, curEncBlockSize)
|
|
|
|
if reader == nil {
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
_, err = io.ReadFull(reader, enBlocks[index])
|
|
|
|
if err != nil && err != io.ErrUnexpectedEOF {
|
|
|
|
readers[index] = nil
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// TODO need to verify block512Sum.
|
|
|
|
|
|
|
|
// Check blocks if they are all zero in length.
|
|
|
|
if checkBlockSize(enBlocks) == 0 {
|
|
|
|
err = errors.New("Data likely corrupted, all blocks are zero in length.")
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Verify the blocks.
|
|
|
|
var ok bool
|
|
|
|
ok, err = xl.ReedSolomon.Verify(enBlocks)
|
|
|
|
if err != nil {
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Verification failed, blocks require reconstruction.
|
|
|
|
if !ok {
|
|
|
|
for index, reader := range readers {
|
|
|
|
if reader == nil {
|
|
|
|
// Reconstruct expects missing blocks to be nil.
|
|
|
|
enBlocks[index] = nil
|
|
|
|
}
|
|
|
|
}
|
|
|
|
err = xl.ReedSolomon.Reconstruct(enBlocks)
|
|
|
|
if err != nil {
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
// Verify reconstructed blocks again.
|
|
|
|
ok, err = xl.ReedSolomon.Verify(enBlocks)
|
|
|
|
if err != nil {
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
if !ok {
|
|
|
|
// Blocks cannot be reconstructed, corrupted data.
|
|
|
|
err = errors.New("Verification failed after reconstruction, data likely corrupted.")
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Join the decoded blocks.
|
|
|
|
err = xl.ReedSolomon.Join(pipeWriter, enBlocks, curBlockSize)
|
|
|
|
if err != nil {
|
|
|
|
pipeWriter.CloseWithError(err)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
// Save what's left after reading erasureBlockSize.
|
|
|
|
totalLeft = totalLeft - erasureBlockSize
|
|
|
|
}
|
|
|
|
|
|
|
|
// Cleanly end the pipe after a successful decoding.
|
|
|
|
pipeWriter.Close()
|
|
|
|
|
|
|
|
// Cleanly close all the underlying data readers.
|
|
|
|
for _, reader := range readers {
|
|
|
|
if reader == nil {
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
reader.Close()
|
|
|
|
}
|
|
|
|
}()
|
|
|
|
|
|
|
|
// Return the pipe for the top level caller to start reading.
|
|
|
|
return pipeReader, nil
|
|
|
|
}
|