minio/cmd/format-disk-cache.go

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// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"context"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"reflect"
"strings"
jsoniter "github.com/json-iterator/go"
"github.com/minio/minio/cmd/logger"
"github.com/minio/sio"
)
const (
// Represents Cache format json holding details on all other cache drives in use.
formatCache = "cache"
// formatCacheV1.Cache.Version
formatCacheVersionV1 = "1"
formatCacheVersionV2 = "2"
formatMetaVersion1 = "1"
formatCacheV1DistributionAlgo = "CRCMOD"
)
// Represents the current cache structure with list of
// disks comprising the disk cache
// formatCacheV1 - structure holds format config version '1'.
type formatCacheV1 struct {
formatMetaV1
Cache struct {
Version string `json:"version"` // Version of 'cache' format.
This string `json:"this"` // This field carries assigned disk uuid.
// Disks field carries the input disk order generated the first
// time when fresh disks were supplied.
Disks []string `json:"disks"`
// Distribution algorithm represents the hashing algorithm
// to pick the right set index for an object.
DistributionAlgo string `json:"distributionAlgo"`
} `json:"cache"` // Cache field holds cache format.
}
// formatCacheV2 is same as formatCacheV1
type formatCacheV2 = formatCacheV1
// Used to detect the version of "cache" format.
type formatCacheVersionDetect struct {
Cache struct {
Version string `json:"version"`
} `json:"cache"`
}
// Return a slice of format, to be used to format uninitialized disks.
func newFormatCacheV2(drives []string) []*formatCacheV2 {
diskCount := len(drives)
var disks = make([]string, diskCount)
var formats = make([]*formatCacheV2, diskCount)
for i := 0; i < diskCount; i++ {
format := &formatCacheV2{}
format.Version = formatMetaVersion1
format.Format = formatCache
format.Cache.Version = formatCacheVersionV2
format.Cache.DistributionAlgo = formatCacheV1DistributionAlgo
format.Cache.This = mustGetUUID()
formats[i] = format
disks[i] = formats[i].Cache.This
}
for i := 0; i < diskCount; i++ {
format := formats[i]
format.Cache.Disks = disks
}
return formats
}
// Returns formatCache.Cache.Version
func formatCacheGetVersion(r io.ReadSeeker) (string, error) {
format := &formatCacheVersionDetect{}
if err := jsonLoad(r, format); err != nil {
return "", err
}
return format.Cache.Version, nil
}
// Creates a new cache format.json if unformatted.
func createFormatCache(fsFormatPath string, format *formatCacheV1) error {
// open file using READ & WRITE permission
var file, err = os.OpenFile(fsFormatPath, os.O_RDWR|os.O_CREATE, 0600)
if err != nil {
return err
}
// Close the locked file upon return.
defer file.Close()
fi, err := file.Stat()
if err != nil {
return err
}
if fi.Size() != 0 {
// format.json already got created because of another minio process's createFormatCache()
return nil
}
return jsonSave(file, format)
}
// This function creates a cache format file on disk and returns a slice
// of format cache config
func initFormatCache(ctx context.Context, drives []string) (formats []*formatCacheV2, err error) {
nformats := newFormatCacheV2(drives)
for i, drive := range drives {
if err = os.MkdirAll(pathJoin(drive, minioMetaBucket), 0777); err != nil {
logger.GetReqInfo(ctx).AppendTags("drive", drive)
logger.LogIf(ctx, err)
return nil, err
}
cacheFormatPath := pathJoin(drive, minioMetaBucket, formatConfigFile)
// Fresh disk - create format.json for this cfs
if err = createFormatCache(cacheFormatPath, nformats[i]); err != nil {
logger.GetReqInfo(ctx).AppendTags("drive", drive)
logger.LogIf(ctx, err)
return nil, err
}
}
return nformats, nil
}
func loadFormatCache(ctx context.Context, drives []string) ([]*formatCacheV2, bool, error) {
formats := make([]*formatCacheV2, len(drives))
var formatV2 *formatCacheV2
migrating := false
for i, drive := range drives {
cacheFormatPath := pathJoin(drive, minioMetaBucket, formatConfigFile)
f, err := os.OpenFile(cacheFormatPath, os.O_RDWR, 0)
if err != nil {
if osIsNotExist(err) {
continue
}
logger.LogIf(ctx, err)
return nil, migrating, err
}
defer f.Close()
format, err := formatMetaCacheV1(f)
if err != nil {
continue
}
formatV2 = format
if format.Cache.Version != formatCacheVersionV2 {
migrating = true
}
formats[i] = formatV2
}
return formats, migrating, nil
}
// unmarshalls the cache format.json into formatCacheV1
func formatMetaCacheV1(r io.ReadSeeker) (*formatCacheV1, error) {
format := &formatCacheV1{}
if err := jsonLoad(r, format); err != nil {
return nil, err
}
return format, nil
}
func checkFormatCacheValue(format *formatCacheV2, migrating bool) error {
if format.Format != formatCache {
return fmt.Errorf("Unsupported cache format [%s] found", format.Format)
}
// during migration one or more cache drive(s) formats can be out of sync
if migrating {
// Validate format version and format type.
if format.Version != formatMetaVersion1 {
return fmt.Errorf("Unsupported version of cache format [%s] found", format.Version)
}
if format.Cache.Version != formatCacheVersionV2 && format.Cache.Version != formatCacheVersionV1 {
return fmt.Errorf("Unsupported Cache backend format found [%s]", format.Cache.Version)
}
return nil
}
// Validate format version and format type.
if format.Version != formatMetaVersion1 {
return fmt.Errorf("Unsupported version of cache format [%s] found", format.Version)
}
if format.Cache.Version != formatCacheVersionV2 {
return fmt.Errorf("Unsupported Cache backend format found [%s]", format.Cache.Version)
}
return nil
}
func checkFormatCacheValues(migrating bool, formats []*formatCacheV2) (int, error) {
for i, formatCache := range formats {
if formatCache == nil {
continue
}
if err := checkFormatCacheValue(formatCache, migrating); err != nil {
return i, err
}
if len(formats) != len(formatCache.Cache.Disks) {
return i, fmt.Errorf("Expected number of cache drives %d , got %d",
len(formatCache.Cache.Disks), len(formats))
}
}
return -1, nil
}
// checkCacheDisksConsistency - checks if "This" disk uuid on each disk is consistent with all "Disks" slices
// across disks.
func checkCacheDiskConsistency(formats []*formatCacheV2) error {
var disks = make([]string, len(formats))
// Collect currently available disk uuids.
for index, format := range formats {
if format == nil {
disks[index] = ""
continue
}
disks[index] = format.Cache.This
}
for i, format := range formats {
if format == nil {
continue
}
j := findCacheDiskIndex(disks[i], format.Cache.Disks)
if j == -1 {
return fmt.Errorf("UUID on positions %d:%d do not match with , expected %s", i, j, disks[i])
}
if i != j {
return fmt.Errorf("UUID on positions %d:%d do not match with , expected %s got %s", i, j, disks[i], format.Cache.Disks[j])
}
}
return nil
}
// checkCacheDisksSliceConsistency - validate cache Disks order if they are consistent.
func checkCacheDisksSliceConsistency(formats []*formatCacheV2) error {
var sentinelDisks []string
// Extract first valid Disks slice.
for _, format := range formats {
if format == nil {
continue
}
sentinelDisks = format.Cache.Disks
break
}
for _, format := range formats {
if format == nil {
continue
}
currentDisks := format.Cache.Disks
if !reflect.DeepEqual(sentinelDisks, currentDisks) {
return errors.New("inconsistent cache drives found")
}
}
return nil
}
// findCacheDiskIndex returns position of cache disk in JBOD.
func findCacheDiskIndex(disk string, disks []string) int {
for index, uuid := range disks {
if uuid == disk {
return index
}
}
return -1
}
// validate whether cache drives order has changed
func validateCacheFormats(ctx context.Context, migrating bool, formats []*formatCacheV2) error {
count := 0
for _, format := range formats {
if format == nil {
count++
}
}
if count == len(formats) {
return errors.New("Cache format files missing on all drives")
}
if _, err := checkFormatCacheValues(migrating, formats); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := checkCacheDisksSliceConsistency(formats); err != nil {
logger.LogIf(ctx, err)
return err
}
err := checkCacheDiskConsistency(formats)
logger.LogIf(ctx, err)
return err
}
// return true if all of the list of cache drives are
// fresh disks
func cacheDrivesUnformatted(drives []string) bool {
count := 0
for _, drive := range drives {
cacheFormatPath := pathJoin(drive, minioMetaBucket, formatConfigFile)
if _, err := os.Stat(cacheFormatPath); osIsNotExist(err) {
count++
}
}
return count == len(drives)
}
// create format.json for each cache drive if fresh disk or load format from disk
// Then validate the format for all drives in the cache to ensure order
// of cache drives has not changed.
func loadAndValidateCacheFormat(ctx context.Context, drives []string) (formats []*formatCacheV2, migrating bool, err error) {
if cacheDrivesUnformatted(drives) {
formats, err = initFormatCache(ctx, drives)
} else {
formats, migrating, err = loadFormatCache(ctx, drives)
}
if err != nil {
return nil, false, err
}
if err = validateCacheFormats(ctx, migrating, formats); err != nil {
return nil, false, err
}
return formats, migrating, nil
}
// reads cached object on disk and writes it back after adding bitrot
// hashsum per block as per the new disk cache format.
func migrateCacheData(ctx context.Context, c *diskCache, bucket, object, oldfile, destDir string, metadata map[string]string) error {
st, err := os.Stat(oldfile)
if err != nil {
err = osErrToFileErr(err)
return err
}
readCloser, err := readCacheFileStream(oldfile, 0, st.Size())
if err != nil {
return err
}
var reader io.Reader = readCloser
actualSize := uint64(st.Size())
if globalCacheKMS != nil {
reader, err = newCacheEncryptReader(readCloser, bucket, object, metadata)
if err != nil {
return err
}
actualSize, _ = sio.EncryptedSize(uint64(st.Size()))
}
_, _, err = c.bitrotWriteToCache(destDir, cacheDataFile, reader, actualSize)
return err
}
// migrate cache contents from old cacheFS format to new backend format
// new format is flat
// sha(bucket,object)/ <== dir name
// - part.1 <== data
// - cache.json <== metadata
func migrateOldCache(ctx context.Context, c *diskCache) error {
oldCacheBucketsPath := path.Join(c.dir, minioMetaBucket, "buckets")
cacheFormatPath := pathJoin(c.dir, minioMetaBucket, formatConfigFile)
if _, err := os.Stat(oldCacheBucketsPath); err != nil {
// remove .minio.sys sub directories
removeAll(path.Join(c.dir, minioMetaBucket, "multipart"))
removeAll(path.Join(c.dir, minioMetaBucket, "tmp"))
removeAll(path.Join(c.dir, minioMetaBucket, "trash"))
removeAll(path.Join(c.dir, minioMetaBucket, "buckets"))
// just migrate cache format
return migrateCacheFormatJSON(cacheFormatPath)
}
buckets, err := readDir(oldCacheBucketsPath)
if err != nil {
return err
}
for _, bucket := range buckets {
bucket = strings.TrimSuffix(bucket, SlashSeparator)
var objMetaPaths []string
root := path.Join(oldCacheBucketsPath, bucket)
err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
if strings.HasSuffix(path, cacheMetaJSONFile) {
objMetaPaths = append(objMetaPaths, path)
}
return nil
})
if err != nil {
return err
}
for _, oMeta := range objMetaPaths {
objSlice := strings.SplitN(oMeta, cacheMetaJSONFile, 2)
object := strings.TrimPrefix(objSlice[0], path.Join(oldCacheBucketsPath, bucket))
object = strings.TrimSuffix(object, "/")
destdir := getCacheSHADir(c.dir, bucket, object)
if err := os.MkdirAll(destdir, 0777); err != nil {
return err
}
prevCachedPath := path.Join(c.dir, bucket, object)
// get old cached metadata
oldMetaPath := pathJoin(oldCacheBucketsPath, bucket, object, cacheMetaJSONFile)
metaPath := pathJoin(destdir, cacheMetaJSONFile)
metaBytes, err := ioutil.ReadFile(oldMetaPath)
if err != nil {
return err
}
// marshal cache metadata after adding version and stat info
meta := &cacheMeta{}
var json = jsoniter.ConfigCompatibleWithStandardLibrary
if err = json.Unmarshal(metaBytes, &meta); err != nil {
return err
}
// move cached object to new cache directory path
// migrate cache data and add bit-rot protection hash sum
// at the start of each block
if err := migrateCacheData(ctx, c, bucket, object, prevCachedPath, destdir, meta.Meta); err != nil {
continue
}
stat, err := os.Stat(prevCachedPath)
if err != nil {
if err == errFileNotFound {
continue
}
logger.LogIf(ctx, err)
return err
}
// old cached file can now be removed
if err := os.Remove(prevCachedPath); err != nil {
return err
}
// move cached metadata after changing cache metadata version
meta.Checksum = CacheChecksumInfoV1{Algorithm: HighwayHash256S.String(), Blocksize: cacheBlkSize}
meta.Version = cacheMetaVersion
meta.Stat.Size = stat.Size()
meta.Stat.ModTime = stat.ModTime()
jsonData, err := json.Marshal(meta)
if err != nil {
return err
}
if err = ioutil.WriteFile(metaPath, jsonData, 0644); err != nil {
return err
}
}
// delete old bucket from cache, now that all contents are cleared
removeAll(path.Join(c.dir, bucket))
}
// remove .minio.sys sub directories
removeAll(path.Join(c.dir, minioMetaBucket, "multipart"))
removeAll(path.Join(c.dir, minioMetaBucket, "tmp"))
removeAll(path.Join(c.dir, minioMetaBucket, "trash"))
removeAll(path.Join(c.dir, minioMetaBucket, "buckets"))
return migrateCacheFormatJSON(cacheFormatPath)
}
func migrateCacheFormatJSON(cacheFormatPath string) error {
// now migrate format.json
f, err := os.OpenFile(cacheFormatPath, os.O_RDWR, 0)
if err != nil {
return err
}
defer f.Close()
formatV1 := formatCacheV1{}
if err := jsonLoad(f, &formatV1); err != nil {
return err
}
formatV2 := &formatCacheV2{}
formatV2.formatMetaV1 = formatV1.formatMetaV1
formatV2.Version = formatMetaVersion1
formatV2.Cache = formatV1.Cache
formatV2.Cache.Version = formatCacheVersionV2
return jsonSave(f, formatV2)
}