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minio/cmd/xl-v1-metadata.go

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/*
* Minio Cloud Storage, (C) 2016, 2017, 2017 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 (
"encoding/json"
"errors"
"path"
"runtime"
"sort"
"sync"
"time"
)
const (
// Erasure related constants.
erasureAlgorithmKlauspost = "klauspost/reedsolomon/vandermonde"
)
// 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"`
}
// byObjectPartNumber is a collection satisfying sort.Interface.
type byObjectPartNumber []objectPartInfo
func (t byObjectPartNumber) Len() int { return len(t) }
func (t byObjectPartNumber) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
func (t byObjectPartNumber) Less(i, j int) bool { return t[i].Number < t[j].Number }
// checkSumInfo - carries checksums of individual scattered parts per disk.
type checkSumInfo struct {
Name string `json:"name"`
Algorithm HashAlgo `json:"algorithm"`
Hash string `json:"hash"`
}
// HashAlgo - represents a supported hashing algorithm for bitrot
// verification.
type HashAlgo string
const (
// HashBlake2b represents the Blake 2b hashing algorithm
HashBlake2b HashAlgo = "blake2b"
// HashSha256 represents the SHA256 hashing algorithm
HashSha256 HashAlgo = "sha256"
)
// isValidHashAlgo - function that checks if the hash algorithm is
// valid (known and used).
func isValidHashAlgo(algo HashAlgo) bool {
switch algo {
case HashSha256, HashBlake2b:
return true
default:
return false
}
}
// Constant indicates current bit-rot algo used when creating objects.
// Depending on the architecture we are choosing a different checksum.
var bitRotAlgo = getDefaultBitRotAlgo()
// Get the default bit-rot algo depending on the architecture.
// Currently this function defaults to "blake2b" as the preferred
// checksum algorithm on all architectures except ARM64. On ARM64
// we use sha256 (optimized using sha2 instructions of ARM NEON chip).
func getDefaultBitRotAlgo() HashAlgo {
switch runtime.GOARCH {
case "arm64":
// As a special case for ARM64 we use an optimized
// version of hash i.e sha256. This is done so that
// blake2b is sub-optimal and slower on ARM64.
// This would also allows erasure coded writes
// on ARM64 servers to be on-par with their
// counter-part X86_64 servers.
return HashSha256
default:
// Default for all other architectures we use blake2b.
return HashBlake2b
}
}
// erasureInfo - carries erasure coding related information, block
// distribution and checksums.
type erasureInfo struct {
Algorithm HashAlgo `json:"algorithm"`
DataBlocks int `json:"data"`
ParityBlocks int `json:"parity"`
BlockSize int64 `json:"blockSize"`
Index int `json:"index"`
Distribution []int `json:"distribution"`
Checksum []checkSumInfo `json:"checksum,omitempty"`
}
// AddCheckSum - add checksum of a part.
func (e *erasureInfo) AddCheckSumInfo(ckSumInfo checkSumInfo) {
for i, sum := range e.Checksum {
if sum.Name == ckSumInfo.Name {
e.Checksum[i] = ckSumInfo
return
}
}
e.Checksum = append(e.Checksum, ckSumInfo)
}
// GetCheckSumInfo - get checksum of a part.
func (e erasureInfo) GetCheckSumInfo(partName string) (ckSum checkSumInfo) {
// Return the checksum.
for _, sum := range e.Checksum {
if sum.Name == partName {
return sum
}
}
return checkSumInfo{Algorithm: bitRotAlgo}
}
// statInfo - carries stat information of the object.
type statInfo struct {
Size int64 `json:"size"` // Size of the object `xl.json`.
ModTime time.Time `json:"modTime"` // ModTime of the object `xl.json`.
}
// A xlMetaV1 represents `xl.json` metadata header.
type xlMetaV1 struct {
Version string `json:"version"` // Version of the current `xl.json`.
Format string `json:"format"` // Format of the current `xl.json`.
Stat statInfo `json:"stat"` // Stat of the current object `xl.json`.
// Erasure coded info for the current object `xl.json`.
Erasure erasureInfo `json:"erasure"`
// Minio release tag for current object `xl.json`.
Minio struct {
Release string `json:"release"`
} `json:"minio"`
// Metadata map for current object `xl.json`.
Meta map[string]string `json:"meta,omitempty"`
// Captures all the individual object `xl.json`.
Parts []objectPartInfo `json:"parts,omitempty"`
}
// XL metadata constants.
const (
// XL meta version.
xlMetaVersion = "1.0.1"
// XL meta version.
xlMetaVersion100 = "1.0.0"
// XL meta format string.
xlMetaFormat = "xl"
// Add new constants here.
)
// newXLMetaV1 - initializes new xlMetaV1, adds version, allocates a fresh erasure info.
func newXLMetaV1(object string, dataBlocks, parityBlocks int) (xlMeta xlMetaV1) {
xlMeta = xlMetaV1{}
xlMeta.Version = xlMetaVersion
xlMeta.Format = xlMetaFormat
xlMeta.Minio.Release = ReleaseTag
xlMeta.Erasure = erasureInfo{
Algorithm: erasureAlgorithmKlauspost,
DataBlocks: dataBlocks,
ParityBlocks: parityBlocks,
BlockSize: blockSizeV1,
Distribution: hashOrder(object, dataBlocks+parityBlocks),
}
return xlMeta
}
// IsValid - tells if the format is sane by validating the version
// string and format style.
func (m xlMetaV1) IsValid() bool {
return isXLMetaValid(m.Version, m.Format)
}
// Verifies if the backend format metadata is sane by validating
// the version string and format style.
func isXLMetaValid(version, format string) bool {
return ((version == xlMetaVersion || version == xlMetaVersion100) &&
format == xlMetaFormat)
}
// Converts metadata to object info.
func (m xlMetaV1) ToObjectInfo(bucket, object string) ObjectInfo {
objInfo := ObjectInfo{
IsDir: false,
Bucket: bucket,
Name: object,
Size: m.Stat.Size,
ModTime: m.Stat.ModTime,
ContentType: m.Meta["content-type"],
ContentEncoding: m.Meta["content-encoding"],
}
// Extract etag from metadata.
objInfo.ETag = extractETag(m.Meta)
// etag/md5Sum has already been extracted. We need to
// remove to avoid it from appearing as part of
// response headers. e.g, X-Minio-* or X-Amz-*.
objInfo.UserDefined = cleanMetaETag(m.Meta)
// Success.
return objInfo
}
// objectPartIndex - returns the index of matching object part number.
func objectPartIndex(parts []objectPartInfo, partNumber int) int {
for i, part := range parts {
if partNumber == part.Number {
return i
}
}
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(byObjectPartNumber(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) {
if offset == 0 {
// Special case - if offset is 0, then partIndex and partOffset are always 0.
return 0, 0, nil
}
partOffset = offset
// Seek until object offset maps to a particular part offset.
for i, part := range m.Parts {
partIndex = i
// 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, traceError(InvalidRange{})
}
// pickValidXLMeta - picks one valid xlMeta content and returns from a
// slice of xlmeta content. If no value is found this function panics
// and dies.
func pickValidXLMeta(metaArr []xlMetaV1, modTime time.Time) (xlMetaV1, error) {
// Pick latest valid metadata.
for _, meta := range metaArr {
if meta.IsValid() && meta.Stat.ModTime.Equal(modTime) {
return meta, nil
}
}
return xlMetaV1{}, traceError(errors.New("No valid xl.json present"))
}
// list of all errors that can be ignored in a metadata operation.
var objMetadataOpIgnoredErrs = append(baseIgnoredErrs, errDiskAccessDenied, errVolumeNotFound, errFileNotFound, errFileAccessDenied, errCorruptedFormat)
// readXLMetaParts - returns the XL Metadata Parts from xl.json of one of the disks picked at random.
func (xl xlObjects) readXLMetaParts(bucket, object string) (xlMetaParts []objectPartInfo, err error) {
var ignoredErrs []error
for _, disk := range xl.getLoadBalancedDisks() {
if disk == nil {
ignoredErrs = append(ignoredErrs, errDiskNotFound)
continue
}
xlMetaParts, err = readXLMetaParts(disk, bucket, object)
if err == nil {
return xlMetaParts, nil
}
// For any reason disk or bucket is not available continue
// and read from other disks.
if isErrIgnored(err, objMetadataOpIgnoredErrs...) {
ignoredErrs = append(ignoredErrs, err)
continue
}
// Error is not ignored, return right here.
return nil, err
}
// If all errors were ignored, reduce to maximal occurrence
// based on the read quorum.
return nil, reduceReadQuorumErrs(ignoredErrs, nil, xl.readQuorum)
}
// readXLMetaStat - return xlMetaV1.Stat and xlMetaV1.Meta from one of the disks picked at random.
func (xl xlObjects) readXLMetaStat(bucket, object string) (xlStat statInfo, xlMeta map[string]string, err error) {
var ignoredErrs []error
for _, disk := range xl.getLoadBalancedDisks() {
if disk == nil {
ignoredErrs = append(ignoredErrs, errDiskNotFound)
continue
}
// parses only xlMetaV1.Meta and xlMeta.Stat
xlStat, xlMeta, err = readXLMetaStat(disk, bucket, object)
if err == nil {
return xlStat, xlMeta, nil
}
// For any reason disk or bucket is not available continue
// and read from other disks.
if isErrIgnored(err, objMetadataOpIgnoredErrs...) {
ignoredErrs = append(ignoredErrs, err)
continue
}
// Error is not ignored, return right here.
return statInfo{}, nil, err
}
// If all errors were ignored, reduce to maximal occurrence
// based on the read quorum.
return statInfo{}, nil, reduceReadQuorumErrs(ignoredErrs, nil, xl.readQuorum)
}
// deleteXLMetadata - deletes `xl.json` on a single disk.
func deleteXLMetdata(disk StorageAPI, bucket, prefix string) error {
jsonFile := path.Join(prefix, xlMetaJSONFile)
return traceError(disk.DeleteFile(bucket, jsonFile))
}
// writeXLMetadata - writes `xl.json` to a single disk.
func writeXLMetadata(disk StorageAPI, bucket, prefix string, xlMeta xlMetaV1) error {
jsonFile := path.Join(prefix, xlMetaJSONFile)
// Marshal json.
metadataBytes, err := json.Marshal(&xlMeta)
if err != nil {
return traceError(err)
}
// Persist marshalled data.
return traceError(disk.AppendFile(bucket, jsonFile, metadataBytes))
}
// deleteAllXLMetadata - deletes all partially written `xl.json` depending on errs.
func deleteAllXLMetadata(disks []StorageAPI, bucket, prefix string, errs []error) {
var wg = &sync.WaitGroup{}
// Delete all the `xl.json` left over.
for index, disk := range disks {
if disk == nil {
continue
}
// Undo rename object in parallel.
wg.Add(1)
go func(index int, disk StorageAPI) {
defer wg.Done()
if errs[index] != nil {
return
}
_ = deleteXLMetdata(disk, bucket, prefix)
}(index, disk)
}
wg.Wait()
}
// Rename `xl.json` content to destination location for each disk in order.
func renameXLMetadata(disks []StorageAPI, srcBucket, srcEntry, dstBucket, dstEntry string, quorum int) error {
isDir := false
srcXLJSON := path.Join(srcEntry, xlMetaJSONFile)
dstXLJSON := path.Join(dstEntry, xlMetaJSONFile)
return rename(disks, srcBucket, srcXLJSON, dstBucket, dstXLJSON, isDir, quorum)
}
// writeUniqueXLMetadata - writes unique `xl.json` content for each disk in order.
func writeUniqueXLMetadata(disks []StorageAPI, bucket, prefix string, xlMetas []xlMetaV1, quorum int) error {
var wg = &sync.WaitGroup{}
var mErrs = make([]error, len(disks))
// Start writing `xl.json` to all disks in parallel.
for index, disk := range disks {
if disk == nil {
mErrs[index] = traceError(errDiskNotFound)
continue
}
wg.Add(1)
// Write `xl.json` in a routine.
go func(index int, disk StorageAPI) {
defer wg.Done()
// Pick one xlMeta for a disk at index.
xlMetas[index].Erasure.Index = index + 1
// Write unique `xl.json` for a disk at index.
err := writeXLMetadata(disk, bucket, prefix, xlMetas[index])
if err != nil {
mErrs[index] = err
// Ignore disk which returned an error.
disks[index] = nil
}
}(index, disk)
}
// Wait for all the routines.
wg.Wait()
err := reduceWriteQuorumErrs(mErrs, objectOpIgnoredErrs, quorum)
if errorCause(err) == errXLWriteQuorum {
// Delete all `xl.json` successfully renamed.
deleteAllXLMetadata(disks, bucket, prefix, mErrs)
}
return err
}
// writeSameXLMetadata - write `xl.json` on all disks in order.
func writeSameXLMetadata(disks []StorageAPI, bucket, prefix string, xlMeta xlMetaV1, writeQuorum, readQuorum int) error {
var wg = &sync.WaitGroup{}
var mErrs = make([]error, len(disks))
// Start writing `xl.json` to all disks in parallel.
for index, disk := range disks {
if disk == nil {
mErrs[index] = traceError(errDiskNotFound)
continue
}
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
// Write xl metadata.
err := writeXLMetadata(disk, bucket, prefix, metadata)
if err != nil {
mErrs[index] = err
// Ignore disk which returned an error.
disks[index] = nil
}
}(index, disk, xlMeta)
}
// Wait for all the routines.
wg.Wait()
err := reduceWriteQuorumErrs(mErrs, objectOpIgnoredErrs, writeQuorum)
if errorCause(err) == errXLWriteQuorum {
// Delete all `xl.json` successfully renamed.
deleteAllXLMetadata(disks, bucket, prefix, mErrs)
}
return err
}