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minio/xl-v1-metadata.go

258 lines
7.2 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 main
import (
"encoding/json"
"path"
"sort"
"sync"
"time"
)
const (
// Erasure related constants.
erasureAlgorithmKlauspost = "klauspost/reedsolomon/vandermonde"
erasureAlgorithmISAL = "isa-l/reedsolomon/cauchy"
)
// objectPartInfo Info of each part kept in the multipart metadata
// file after CompleteMultipartUpload() is called.
type objectPartInfo struct {
Number int `json:"number"`
Name string `json:"name"`
ETag string `json:"etag"`
Size int64 `json:"size"`
}
// byPartName is a collection satisfying sort.Interface.
type byPartNumber []objectPartInfo
func (t byPartNumber) Len() int { return len(t) }
func (t byPartNumber) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
func (t byPartNumber) Less(i, j int) bool { return t[i].Number < t[j].Number }
// A xlMetaV1 represents a metadata header mapping keys to sets of values.
type xlMetaV1 struct {
Version string `json:"version"`
Format string `json:"format"`
Stat struct {
Size int64 `json:"size"`
ModTime time.Time `json:"modTime"`
Version int64 `json:"version"`
} `json:"stat"`
Erasure struct {
Algorithm string `json:"algorithm"`
DataBlocks int `json:"data"`
ParityBlocks int `json:"parity"`
BlockSize int64 `json:"blockSize"`
Index int `json:"index"`
Distribution []int `json:"distribution"`
Checksum []struct {
Name string `json:"name"`
Algorithm string `json:"algorithm"`
Hash string `json:"hash"`
} `json:"checksum"`
} `json:"erasure"`
Minio struct {
Release string `json:"release"`
} `json:"minio"`
Meta map[string]string `json:"meta"`
Parts []objectPartInfo `json:"parts,omitempty"`
}
// newXLMetaV1 - initializes new xlMetaV1.
func newXLMetaV1(dataBlocks, parityBlocks int) (xlMeta xlMetaV1) {
xlMeta = xlMetaV1{}
xlMeta.Version = "1"
xlMeta.Format = "xl"
xlMeta.Minio.Release = minioReleaseTag
xlMeta.Erasure.Algorithm = erasureAlgorithmKlauspost
xlMeta.Erasure.DataBlocks = dataBlocks
xlMeta.Erasure.ParityBlocks = parityBlocks
xlMeta.Erasure.BlockSize = blockSizeV1
xlMeta.Erasure.Distribution = randInts(dataBlocks + parityBlocks)
return xlMeta
}
// ObjectPartIndex - returns the index of matching object part number.
func (m xlMetaV1) ObjectPartIndex(partNumber int) (index int) {
for i, part := range m.Parts {
if partNumber == part.Number {
index = i
return index
}
}
return -1
}
// AddObjectPart - add a new object part in order.
func (m *xlMetaV1) AddObjectPart(partNumber int, partName string, partETag string, partSize int64) {
partInfo := objectPartInfo{
Number: partNumber,
Name: partName,
ETag: partETag,
Size: partSize,
}
// Update part info if it already exists.
for i, part := range m.Parts {
if partNumber == part.Number {
m.Parts[i] = partInfo
return
}
}
// Proceed to include new part info.
m.Parts = append(m.Parts, partInfo)
// Parts in xlMeta should be in sorted order by part number.
sort.Sort(byPartNumber(m.Parts))
}
// objectToPartOffset - translate offset of an object to offset of its individual part.
func (m xlMetaV1) objectToPartOffset(offset int64) (partIndex int, partOffset int64, err error) {
partOffset = offset
// Seek until object offset maps to a particular part offset.
for i, part := range m.Parts {
partIndex = i
// Last part can be of '0' bytes, treat it specially and
// return right here.
if part.Size == 0 {
return partIndex, partOffset, nil
}
// Offset is smaller than size we have reached the proper part offset.
if partOffset < part.Size {
return partIndex, partOffset, nil
}
// Continue to towards the next part.
partOffset -= part.Size
}
// Offset beyond the size of the object return InvalidRange.
return 0, 0, InvalidRange{}
}
// readXLMetadata - returns the object metadata `xl.json` content from
// one of the disks picked at random.
func (xl xlObjects) readXLMetadata(bucket, object string) (xlMeta xlMetaV1, err error) {
// Count for errors encountered.
var xlJSONErrCount = 0
// Return the first successful lookup from a random list of disks.
for xlJSONErrCount < len(xl.storageDisks) {
disk := xl.getRandomDisk() // Choose a random disk on each attempt.
var buffer []byte
buffer, err = readAll(disk, bucket, path.Join(object, xlMetaJSONFile))
if err == nil {
err = json.Unmarshal(buffer, &xlMeta)
if err == nil {
return xlMeta, nil
}
}
xlJSONErrCount++ // Update error count.
}
return xlMetaV1{}, err
}
// renameXLMetadata - renames `xl.json` from source prefix to destination prefix.
func (xl xlObjects) renameXLMetadata(srcBucket, srcPrefix, dstBucket, dstPrefix string) error {
var wg = &sync.WaitGroup{}
var mErrs = make([]error, len(xl.storageDisks))
srcJSONFile := path.Join(srcPrefix, xlMetaJSONFile)
dstJSONFile := path.Join(dstPrefix, xlMetaJSONFile)
// Rename `xl.json` to all disks in parallel.
for index, disk := range xl.storageDisks {
wg.Add(1)
// Rename `xl.json` in a routine.
go func(index int, disk StorageAPI) {
defer wg.Done()
// Renames `xl.json` from source prefix to destination prefix.
rErr := disk.RenameFile(srcBucket, srcJSONFile, dstBucket, dstJSONFile)
if rErr != nil {
mErrs[index] = rErr
return
}
// Delete any dangling directories.
dErr := disk.DeleteFile(srcBucket, srcPrefix)
if dErr != nil {
mErrs[index] = dErr
return
}
mErrs[index] = nil
}(index, disk)
}
// Wait for all the routines.
wg.Wait()
// Return the first error.
for _, err := range mErrs {
if err == nil {
continue
}
return err
}
return nil
}
// writeXLMetadata - write `xl.json` on all disks in order.
func (xl xlObjects) writeXLMetadata(bucket, prefix string, xlMeta xlMetaV1) error {
var wg = &sync.WaitGroup{}
var mErrs = make([]error, len(xl.storageDisks))
jsonFile := path.Join(prefix, xlMetaJSONFile)
// Start writing `xl.json` to all disks in parallel.
for index, disk := range xl.storageDisks {
wg.Add(1)
// Write `xl.json` in a routine.
go func(index int, disk StorageAPI, metadata xlMetaV1) {
defer wg.Done()
// Save the disk order index.
metadata.Erasure.Index = index + 1
metadataBytes, err := json.Marshal(&metadata)
if err != nil {
mErrs[index] = err
return
}
// Persist marshalled data.
n, mErr := disk.AppendFile(bucket, jsonFile, metadataBytes)
if mErr != nil {
mErrs[index] = mErr
return
}
if n != int64(len(metadataBytes)) {
mErrs[index] = errUnexpected
return
}
mErrs[index] = nil
}(index, disk, xlMeta)
}
// Wait for all the routines.
wg.Wait()
// Return the first error.
for _, err := range mErrs {
if err == nil {
continue
}
return err
}
return nil
}