minio/cmd/disk-cache-fs.go

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/*
* Minio Cloud Storage, (C) 2018 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 (
"context"
"encoding/hex"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"sync"
"time"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/disk"
"github.com/minio/minio/pkg/lock"
)
const (
// cache.json object metadata for cached objects.
cacheMetaJSONFile = "cache.json"
cacheEnvDelimiter = ";"
)
// cacheFSObjects implements the cache backend operations.
type cacheFSObjects struct {
*FSObjects
// caching drive path (from cache "drives" in config.json)
dir string
// expiry in days specified in config.json
expiry int
// max disk usage pct
maxDiskUsagePct int
// purge() listens on this channel to start the cache-purge process
purgeChan chan struct{}
// mark false if drive is offline
online bool
// mutex to protect updates to online variable
onlineMutex *sync.RWMutex
}
// Inits the cache directory if it is not init'ed already.
// Initializing implies creation of new FS Object layer.
func newCacheFSObjects(dir string, expiry int, maxDiskUsagePct int) (*cacheFSObjects, error) {
// Assign a new UUID for FS minio mode. Each server instance
// gets its own UUID for temporary file transaction.
fsUUID := mustGetUUID()
// Initialize meta volume, if volume already exists ignores it.
if err := initMetaVolumeFS(dir, fsUUID); err != nil {
return nil, fmt.Errorf("Unable to initialize '.minio.sys' meta volume, %s", err)
}
trashPath := pathJoin(dir, minioMetaBucket, cacheTrashDir)
if err := os.MkdirAll(trashPath, 0777); err != nil {
return nil, err
}
if expiry == 0 {
expiry = globalCacheExpiry
}
// Initialize fs objects.
fsObjects := &FSObjects{
fsPath: dir,
metaJSONFile: cacheMetaJSONFile,
fsUUID: fsUUID,
rwPool: &fsIOPool{
readersMap: make(map[string]*lock.RLockedFile),
},
nsMutex: newNSLock(false),
listPool: newTreeWalkPool(globalLookupTimeout),
appendFileMap: make(map[string]*fsAppendFile),
}
go fsObjects.cleanupStaleMultipartUploads(context.Background(), globalMultipartCleanupInterval, globalMultipartExpiry, globalServiceDoneCh)
cacheFS := cacheFSObjects{
FSObjects: fsObjects,
dir: dir,
expiry: expiry,
maxDiskUsagePct: maxDiskUsagePct,
purgeChan: make(chan struct{}),
online: true,
onlineMutex: &sync.RWMutex{},
}
return &cacheFS, nil
}
// Returns if the disk usage is low.
// Disk usage is low if usage is < 80% of cacheMaxDiskUsagePct
// Ex. for a 100GB disk, if maxUsage is configured as 70% then cacheMaxDiskUsagePct is 70G
// hence disk usage is low if the disk usage is less than 56G (because 80% of 70G is 56G)
func (cfs *cacheFSObjects) diskUsageLow() bool {
minUsage := cfs.maxDiskUsagePct * 80 / 100
di, err := disk.GetInfo(cfs.dir)
if err != nil {
reqInfo := (&logger.ReqInfo{}).AppendTags("cachePath", cfs.dir)
ctx := logger.SetReqInfo(context.Background(), reqInfo)
logger.LogIf(ctx, err)
return false
}
usedPercent := (di.Total - di.Free) * 100 / di.Total
return int(usedPercent) < minUsage
}
// Return if the disk usage is high.
// Disk usage is high if disk used is > cacheMaxDiskUsagePct
func (cfs *cacheFSObjects) diskUsageHigh() bool {
di, err := disk.GetInfo(cfs.dir)
if err != nil {
reqInfo := (&logger.ReqInfo{}).AppendTags("cachePath", cfs.dir)
ctx := logger.SetReqInfo(context.Background(), reqInfo)
logger.LogIf(ctx, err)
return true
}
usedPercent := (di.Total - di.Free) * 100 / di.Total
return int(usedPercent) > cfs.maxDiskUsagePct
}
// Returns if size space can be allocated without exceeding
// max disk usable for caching
func (cfs *cacheFSObjects) diskAvailable(size int64) bool {
di, err := disk.GetInfo(cfs.dir)
if err != nil {
reqInfo := (&logger.ReqInfo{}).AppendTags("cachePath", cfs.dir)
ctx := logger.SetReqInfo(context.Background(), reqInfo)
logger.LogIf(ctx, err)
return false
}
usedPercent := (di.Total - (di.Free - uint64(size))) * 100 / di.Total
return int(usedPercent) < cfs.maxDiskUsagePct
}
// purges all content marked trash from the cache.
func (cfs *cacheFSObjects) purgeTrash() {
ticker := time.NewTicker(time.Minute * cacheCleanupInterval)
defer ticker.Stop()
for {
select {
case <-globalServiceDoneCh:
return
case <-ticker.C:
trashPath := path.Join(cfs.fsPath, minioMetaBucket, cacheTrashDir)
entries, err := readDir(trashPath)
if err != nil {
return
}
for _, entry := range entries {
ctx := logger.SetReqInfo(context.Background(), &logger.ReqInfo{})
fi, err := fsStatVolume(ctx, pathJoin(trashPath, entry))
if err != nil {
continue
}
dir := path.Join(trashPath, fi.Name())
// Delete all expired cache content.
fsRemoveAll(ctx, dir)
}
}
}
}
// Purge cache entries that were not accessed.
func (cfs *cacheFSObjects) purge() {
delimiter := slashSeparator
maxKeys := 1000
ctx := context.Background()
for {
olderThan := cfs.expiry
for !cfs.diskUsageLow() {
// delete unaccessed objects older than expiry duration
expiry := UTCNow().AddDate(0, 0, -1*olderThan)
olderThan /= 2
if olderThan < 1 {
break
}
deletedCount := 0
buckets, err := cfs.ListBuckets(ctx)
if err != nil {
logger.LogIf(ctx, err)
}
// Reset cache online status if drive was offline earlier.
if !cfs.IsOnline() {
cfs.setOnline(true)
}
for _, bucket := range buckets {
var continuationToken string
var marker string
for {
objects, err := cfs.ListObjects(ctx, bucket.Name, marker, continuationToken, delimiter, maxKeys)
if err != nil {
break
}
if !objects.IsTruncated {
break
}
marker = objects.NextMarker
for _, object := range objects.Objects {
// purge objects that qualify because of cache-control directives or
// past cache expiry duration.
if !filterFromCache(object.UserDefined) ||
!isStaleCache(object) ||
object.AccTime.After(expiry) {
continue
}
if err = cfs.DeleteObject(ctx, bucket.Name, object.Name); err != nil {
logger.LogIf(ctx, err)
continue
}
deletedCount++
}
}
}
if deletedCount == 0 {
// to avoid a busy loop
time.Sleep(time.Minute * 30)
}
}
<-cfs.purgeChan
}
}
// sets cache drive status
func (cfs *cacheFSObjects) setOnline(status bool) {
cfs.onlineMutex.Lock()
cfs.online = status
cfs.onlineMutex.Unlock()
}
// returns true if cache drive is online
func (cfs *cacheFSObjects) IsOnline() bool {
cfs.onlineMutex.RLock()
defer cfs.onlineMutex.RUnlock()
return cfs.online
}
// Caches the object to disk
func (cfs *cacheFSObjects) Put(ctx context.Context, bucket, object string, data *PutObjReader, metadata map[string]string, opts ObjectOptions) error {
if cfs.diskUsageHigh() {
select {
case cfs.purgeChan <- struct{}{}:
default:
}
return errDiskFull
}
if !cfs.diskAvailable(data.Size()) {
return errDiskFull
}
if _, err := cfs.GetBucketInfo(ctx, bucket); err != nil {
pErr := cfs.MakeBucketWithLocation(ctx, bucket, "")
if pErr != nil {
return pErr
}
}
_, err := cfs.PutObject(ctx, bucket, object, data, metadata, opts)
// if err is due to disk being offline , mark cache drive as offline
if IsErr(err, baseErrs...) {
cfs.setOnline(false)
}
return err
}
// Returns the handle for the cached object
func (cfs *cacheFSObjects) Get(ctx context.Context, bucket, object string, startOffset int64, length int64, writer io.Writer, etag string, opts ObjectOptions) (err error) {
return cfs.GetObject(ctx, bucket, object, startOffset, length, writer, etag, opts)
}
// Deletes the cached object
func (cfs *cacheFSObjects) Delete(ctx context.Context, bucket, object string) (err error) {
return cfs.DeleteObject(ctx, bucket, object)
}
// convenience function to check if object is cached on this cacheFSObjects
func (cfs *cacheFSObjects) Exists(ctx context.Context, bucket, object string) bool {
_, err := cfs.GetObjectInfo(ctx, bucket, object, ObjectOptions{})
return err == nil
}
// Identical to fs PutObject operation except that it uses ETag in metadata
// headers.
func (cfs *cacheFSObjects) PutObject(ctx context.Context, bucket string, object string, r *PutObjReader, metadata map[string]string, opts ObjectOptions) (objInfo ObjectInfo, retErr error) {
data := r.Reader
fs := cfs.FSObjects
// Lock the object.
objectLock := fs.nsMutex.NewNSLock(bucket, object)
if err := objectLock.GetLock(globalObjectTimeout); err != nil {
return objInfo, err
}
defer objectLock.Unlock()
// No metadata is set, allocate a new one.
meta := make(map[string]string)
for k, v := range metadata {
meta[k] = v
}
var err error
// Validate if bucket name is valid and exists.
if _, err = fs.statBucketDir(ctx, bucket); err != nil {
return ObjectInfo{}, toObjectErr(err, bucket)
}
fsMeta := newFSMetaV1()
fsMeta.Meta = meta
// This is a special case with size as '0' and object ends
// with a slash separator, we treat it like a valid operation
// and return success.
if isObjectDir(object, data.Size()) {
// Check if an object is present as one of the parent dir.
if fs.parentDirIsObject(ctx, bucket, path.Dir(object)) {
return ObjectInfo{}, toObjectErr(errFileAccessDenied, bucket, object)
}
if err = mkdirAll(pathJoin(fs.fsPath, bucket, object), 0777); err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
var fi os.FileInfo
if fi, err = fsStatDir(ctx, pathJoin(fs.fsPath, bucket, object)); err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
return fsMeta.ToObjectInfo(bucket, object, fi), nil
}
if err = checkPutObjectArgs(ctx, bucket, object, fs, data.Size()); err != nil {
return ObjectInfo{}, err
}
// Check if an object is present as one of the parent dir.
if fs.parentDirIsObject(ctx, bucket, path.Dir(object)) {
return ObjectInfo{}, toObjectErr(errFileAccessDenied, bucket, object)
}
// Validate input data size and it can never be less than zero.
if data.Size() < -1 {
logger.LogIf(ctx, errInvalidArgument)
return ObjectInfo{}, errInvalidArgument
}
var wlk *lock.LockedFile
if bucket != minioMetaBucket {
bucketMetaDir := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix)
fsMetaPath := pathJoin(bucketMetaDir, bucket, object, fs.metaJSONFile)
wlk, err = fs.rwPool.Create(fsMetaPath)
if err != nil {
logger.LogIf(ctx, err)
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
// This close will allow for locks to be synchronized on `fs.json`.
defer wlk.Close()
defer func() {
// Remove meta file when PutObject encounters any error
if retErr != nil {
tmpDir := pathJoin(fs.fsPath, minioMetaTmpBucket, fs.fsUUID)
fsRemoveMeta(ctx, bucketMetaDir, fsMetaPath, tmpDir)
}
}()
}
// Uploaded object will first be written to the temporary location which will eventually
// be renamed to the actual location. It is first written to the temporary location
// so that cleaning it up will be easy if the server goes down.
tempObj := mustGetUUID()
// Allocate a buffer to Read() from request body
bufSize := int64(readSizeV1)
if size := data.Size(); size > 0 && bufSize > size {
bufSize = size
}
buf := make([]byte, int(bufSize))
fsTmpObjPath := pathJoin(fs.fsPath, minioMetaTmpBucket, fs.fsUUID, tempObj)
bytesWritten, err := fsCreateFile(ctx, fsTmpObjPath, data, buf, data.Size())
if err != nil {
fsRemoveFile(ctx, fsTmpObjPath)
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
if fsMeta.Meta["etag"] == "" {
fsMeta.Meta["etag"] = hex.EncodeToString(data.MD5Current())
}
// Should return IncompleteBody{} error when reader has fewer
// bytes than specified in request header.
if bytesWritten < data.Size() {
fsRemoveFile(ctx, fsTmpObjPath)
return ObjectInfo{}, IncompleteBody{}
}
// Delete the temporary object in the case of a
// failure. If PutObject succeeds, then there would be
// nothing to delete.
defer fsRemoveFile(ctx, fsTmpObjPath)
// Entire object was written to the temp location, now it's safe to rename it to the actual location.
fsNSObjPath := pathJoin(fs.fsPath, bucket, object)
if err = fsRenameFile(ctx, fsTmpObjPath, fsNSObjPath); err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
if bucket != minioMetaBucket {
// Write FS metadata after a successful namespace operation.
if _, err = fsMeta.WriteTo(wlk); err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
}
// Stat the file to fetch timestamp, size.
fi, err := fsStatFile(ctx, pathJoin(fs.fsPath, bucket, object))
if err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
// Success.
return fsMeta.ToObjectInfo(bucket, object, fi), nil
}
// Implements S3 compatible initiate multipart API. Operation here is identical
// to fs backend implementation - with the exception that cache FS uses the uploadID
// generated on the backend
func (cfs *cacheFSObjects) NewMultipartUpload(ctx context.Context, bucket, object string, meta map[string]string, uploadID string, opts ObjectOptions) (string, error) {
if cfs.diskUsageHigh() {
select {
case cfs.purgeChan <- struct{}{}:
default:
}
return "", errDiskFull
}
if _, err := cfs.GetBucketInfo(ctx, bucket); err != nil {
pErr := cfs.MakeBucketWithLocation(ctx, bucket, "")
if pErr != nil {
return "", pErr
}
}
fs := cfs.FSObjects
if err := checkNewMultipartArgs(ctx, bucket, object, fs); err != nil {
return "", toObjectErr(err, bucket)
}
if _, err := fs.statBucketDir(ctx, bucket); err != nil {
return "", toObjectErr(err, bucket)
}
uploadIDDir := fs.getUploadIDDir(bucket, object, uploadID)
err := mkdirAll(uploadIDDir, 0755)
if err != nil {
logger.LogIf(ctx, err)
return "", err
}
// Initialize fs.json values.
fsMeta := newFSMetaV1()
fsMeta.Meta = meta
fsMetaBytes, err := json.Marshal(fsMeta)
if err != nil {
logger.LogIf(ctx, err)
return "", err
}
if err = ioutil.WriteFile(pathJoin(uploadIDDir, fs.metaJSONFile), fsMetaBytes, 0644); err != nil {
logger.LogIf(ctx, err)
return "", err
}
return uploadID, nil
}
// moveBucketToTrash clears cacheFSObjects of bucket contents and moves it to trash folder.
func (cfs *cacheFSObjects) moveBucketToTrash(ctx context.Context, bucket string) (err error) {
fs := cfs.FSObjects
bucketLock := fs.nsMutex.NewNSLock(bucket, "")
if err = bucketLock.GetLock(globalObjectTimeout); err != nil {
return err
}
defer bucketLock.Unlock()
bucketDir, err := fs.getBucketDir(ctx, bucket)
if err != nil {
return toObjectErr(err, bucket)
}
trashPath := pathJoin(cfs.fsPath, minioMetaBucket, cacheTrashDir)
expiredDir := path.Join(trashPath, bucket)
// Attempt to move regular bucket to expired directory.
if err = fsRenameDir(bucketDir, expiredDir); err != nil {
logger.LogIf(ctx, err)
return toObjectErr(err, bucket)
}
// Cleanup all the bucket metadata.
ominioMetadataBucketDir := pathJoin(fs.fsPath, minioMetaBucket, bucketMetaPrefix, bucket)
nminioMetadataBucketDir := pathJoin(trashPath, MustGetUUID())
logger.LogIf(ctx, fsRenameDir(ominioMetadataBucketDir, nminioMetadataBucketDir))
return nil
}
// Removes a directory only if its empty, handles long
// paths for windows automatically.
func fsRenameDir(dirPath, newPath string) (err error) {
if dirPath == "" || newPath == "" {
return errInvalidArgument
}
if err = checkPathLength(dirPath); err != nil {
return err
}
if err = checkPathLength(newPath); err != nil {
return err
}
if err = os.Rename(dirPath, newPath); err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
} else if isSysErrNotEmpty(err) {
return errVolumeNotEmpty
}
return err
}
return nil
}