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minio/cmd/fs-v1-metadata.go

376 lines
9.7 KiB

/*
* 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"
"io"
"io/ioutil"
"os"
pathutil "path"
"sort"
"strings"
"time"
"github.com/minio/minio/pkg/lock"
"github.com/minio/minio/pkg/mimedb"
"github.com/tidwall/gjson"
)
// FS format, and object metadata.
const (
// fs.json object metadata.
fsMetaJSONFile = "fs.json"
)
// FS metadata constants.
const (
// FS backend meta 1.0.0 version.
fsMetaVersion100 = "1.0.0"
// FS backend meta 1.0.1 version.
fsMetaVersion = "1.0.1"
// FS backend meta format.
fsMetaFormat = "fs"
// Add more constants here.
)
// A fsMetaV1 represents a metadata header mapping keys to sets of values.
type fsMetaV1 struct {
Version string `json:"version"`
Format string `json:"format"`
Minio struct {
Release string `json:"release"`
} `json:"minio"`
// Metadata map for current object `fs.json`.
Meta map[string]string `json:"meta,omitempty"`
Parts []objectPartInfo `json:"parts,omitempty"`
}
// IsValid - tells if the format is sane by validating the version
// string and format style.
func (m fsMetaV1) IsValid() bool {
return isFSMetaValid(m.Version, m.Format)
}
// Verifies if the backend format metadata is sane by validating
// the version string and format style.
func isFSMetaValid(version, format string) bool {
return ((version == fsMetaVersion || version == fsMetaVersion100) &&
format == fsMetaFormat)
}
// Converts metadata to object info.
func (m fsMetaV1) ToObjectInfo(bucket, object string, fi os.FileInfo) ObjectInfo {
if len(m.Meta) == 0 {
m.Meta = make(map[string]string)
}
// Guess content-type from the extension if possible.
if m.Meta["content-type"] == "" {
if objectExt := pathutil.Ext(object); objectExt != "" {
if content, ok := mimedb.DB[strings.ToLower(strings.TrimPrefix(objectExt, "."))]; ok {
m.Meta["content-type"] = content.ContentType
}
}
}
if hasSuffix(object, slashSeparator) {
m.Meta["etag"] = emptyETag // For directories etag is d41d8cd98f00b204e9800998ecf8427e
m.Meta["content-type"] = "application/octet-stream"
}
objInfo := ObjectInfo{
Bucket: bucket,
Name: object,
}
// We set file info only if its valid.
objInfo.ModTime = timeSentinel
if fi != nil {
objInfo.ModTime = fi.ModTime()
objInfo.Size = fi.Size()
if fi.IsDir() {
// Directory is always 0 bytes in S3 API, treat it as such.
objInfo.Size = 0
objInfo.IsDir = fi.IsDir()
}
}
// Extract etag from metadata.
objInfo.ETag = extractETag(m.Meta)
objInfo.ContentType = m.Meta["content-type"]
objInfo.ContentEncoding = m.Meta["content-encoding"]
// 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 (m fsMetaV1) ObjectPartIndex(partNumber int) (partIndex int) {
for i, part := range m.Parts {
if partNumber == part.Number {
partIndex = i
return partIndex
}
}
return -1
}
// AddObjectPart - add a new object part in order.
func (m *fsMetaV1) 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 fsMeta should be in sorted order by part number.
sort.Sort(byObjectPartNumber(m.Parts))
}
func (m *fsMetaV1) WriteTo(lk *lock.LockedFile) (n int64, err error) {
var metadataBytes []byte
metadataBytes, err = json.Marshal(m)
if err != nil {
return 0, traceError(err)
}
if err = lk.Truncate(0); err != nil {
return 0, traceError(err)
}
if _, err = lk.Write(metadataBytes); err != nil {
return 0, traceError(err)
}
// Success.
return int64(len(metadataBytes)), nil
}
func parseFSVersion(fsMetaBuf []byte) string {
return gjson.GetBytes(fsMetaBuf, "version").String()
}
func parseFSFormat(fsMetaBuf []byte) string {
return gjson.GetBytes(fsMetaBuf, "format").String()
}
func parseFSRelease(fsMetaBuf []byte) string {
return gjson.GetBytes(fsMetaBuf, "minio.release").String()
}
func parseFSMetaMap(fsMetaBuf []byte) map[string]string {
// Get xlMetaV1.Meta map.
metaMapResult := gjson.GetBytes(fsMetaBuf, "meta").Map()
metaMap := make(map[string]string)
for key, valResult := range metaMapResult {
metaMap[key] = valResult.String()
}
return metaMap
}
func parseFSParts(fsMetaBuf []byte) []objectPartInfo {
// Parse the FS Parts.
partsResult := gjson.GetBytes(fsMetaBuf, "parts").Array()
partInfo := make([]objectPartInfo, len(partsResult))
for i, p := range partsResult {
info := objectPartInfo{}
info.Number = int(p.Get("number").Int())
info.Name = p.Get("name").String()
info.ETag = p.Get("etag").String()
info.Size = p.Get("size").Int()
partInfo[i] = info
}
return partInfo
}
func (m *fsMetaV1) ReadFrom(lk *lock.LockedFile) (n int64, err error) {
var fsMetaBuf []byte
fi, err := lk.Stat()
if err != nil {
return 0, traceError(err)
}
fsMetaBuf, err = ioutil.ReadAll(io.NewSectionReader(lk, 0, fi.Size()))
if err != nil {
return 0, traceError(err)
}
if len(fsMetaBuf) == 0 {
return 0, traceError(io.EOF)
}
// obtain version.
m.Version = parseFSVersion(fsMetaBuf)
// obtain format.
m.Format = parseFSFormat(fsMetaBuf)
// Verify if the format is valid, return corrupted format
// for unrecognized formats.
if !isFSMetaValid(m.Version, m.Format) {
return 0, traceError(errCorruptedFormat)
}
// obtain metadata.
m.Meta = parseFSMetaMap(fsMetaBuf)
// obtain parts info list.
m.Parts = parseFSParts(fsMetaBuf)
// obtain minio release date.
m.Minio.Release = parseFSRelease(fsMetaBuf)
// Success.
return int64(len(fsMetaBuf)), nil
}
// newFSMetaV1 - initializes new fsMetaV1.
func newFSMetaV1() (fsMeta fsMetaV1) {
fsMeta = fsMetaV1{}
fsMeta.Version = fsMetaVersion
fsMeta.Format = fsMetaFormat
fsMeta.Minio.Release = ReleaseTag
return fsMeta
}
// Check if disk has already a valid format, holds a read lock and
// upon success returns it to the caller to be closed.
func checkLockedValidFormatFS(fsPath string) (*lock.RLockedFile, error) {
fsFormatPath := pathJoin(fsPath, minioMetaBucket, formatConfigFile)
rlk, err := lock.RLockedOpenFile((fsFormatPath))
if err != nil {
if os.IsNotExist(err) {
// If format.json not found then
// its an unformatted disk.
return nil, traceError(errUnformattedDisk)
}
return nil, traceError(err)
}
var format = &formatConfigV1{}
if err = format.LoadFormat(rlk.LockedFile); err != nil {
rlk.Close()
return nil, err
}
// Check format FS.
if err = format.CheckFS(); err != nil {
rlk.Close()
return nil, err
}
// Always return read lock here and should be closed by the caller.
return rlk, traceError(err)
}
// Creates a new format.json if unformatted.
func createFormatFS(fsPath string) error {
fsFormatPath := pathJoin(fsPath, minioMetaBucket, formatConfigFile)
// Attempt a write lock on formatConfigFile `format.json`
// file stored in minioMetaBucket(.minio.sys) directory.
lk, err := lock.TryLockedOpenFile((fsFormatPath), os.O_RDWR|os.O_CREATE, 0600)
if err != nil {
return traceError(err)
}
// Close the locked file upon return.
defer lk.Close()
// Load format on disk, checks if we are unformatted
// writes the new format.json
var format = &formatConfigV1{}
err = format.LoadFormat(lk)
if errorCause(err) == errUnformattedDisk {
_, err = newFSFormat().WriteTo(lk)
return err
}
return err
}
func initFormatFS(fsPath string) (rlk *lock.RLockedFile, err error) {
// This loop validates format.json by holding a read lock and
// proceeds if disk unformatted to hold non-blocking WriteLock
// If for some reason non-blocking WriteLock fails and the error
// is lock.ErrAlreadyLocked i.e some other process is holding a
// lock we retry in the loop again.
for {
// Validate the `format.json` for expected values.
rlk, err = checkLockedValidFormatFS(fsPath)
switch {
case err == nil:
// Holding a read lock ensures that any write lock operation
// is blocked if attempted in-turn avoiding corruption on
// the backend disk.
return rlk, nil
case errorCause(err) == errUnformattedDisk:
if err = createFormatFS(fsPath); err != nil {
// Existing write locks detected.
if errorCause(err) == lock.ErrAlreadyLocked {
// Lock already present, sleep and attempt again.
time.Sleep(100 * time.Millisecond)
continue
}
// Unexpected error, return.
return nil, err
}
// Loop will continue to attempt a read-lock on `format.json`.
default:
// Unhandled error return.
return nil, err
}
}
}
// Return if the part info in uploadedParts and CompleteParts are same.
func isPartsSame(uploadedParts []objectPartInfo, CompleteParts []CompletePart) bool {
if len(uploadedParts) != len(CompleteParts) {
return false
}
for i := range CompleteParts {
if uploadedParts[i].Number != CompleteParts[i].PartNumber ||
uploadedParts[i].ETag != CompleteParts[i].ETag {
return false
}
}
return true
}