return ObjectNameInvalid{Bucket: bucket, Object: object}
	}
	return nil
}

// Checks for all ListObjects arguments validity.
func checkListObjsArgs(ctx context.Context, bucket, prefix, marker string) error {
	// Verify if bucket is valid.
	if !isMinioMetaBucketName(bucket) && s3utils.CheckValidBucketNameStrict(bucket) != nil {
		return BucketNameInvalid{Bucket: bucket}
	}

type ListMultipartsInfo struct {
	// Together with upload-id-marker, this parameter specifies the multipart upload
	// after which listing should begin.
	KeyMarker string

	// Together with key-marker, specifies the multipart upload after which listing
	// should begin. If key-marker is not specified, the upload-id-marker parameter
	// is ignored.
	UploadIDMarker string

	[]madmin.ConfigHistoryEntry, error,
) {
	var configHistory []madmin.ConfigHistoryEntry

	// List all kvs
	marker := ""
	for {
		res, err := objAPI.ListObjects(ctx, minioMetaBucket, minioConfigHistoryPrefix, marker, "", maxObjectList)
		if err != nil {
			return nil, err
		}
		for _, obj := range res.Objects {
			cfgEntry := madmin.ConfigHistoryEntry{

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package target

import (
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

type lazyInit struct {
	done uint32
	m    sync.Mutex
}

func (l *lazyInit) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

// Originally from https://github.com/gorilla/handlers with following license
// https://raw.githubusercontent.com/gorilla/handlers/master/LICENSE, forked
// and heavily modified for MinIO's internal needs.

package handlers

import (
	"net"
	"net/http"
	"regexp"
	"strings"
)

var (
	// De-facto standard header keys.

func listObjectParities(partsMetadata []FileInfo, errs []error) (parities []int) {
	parities = make([]int, len(partsMetadata))
	for index, metadata := range partsMetadata {
		if errs[index] != nil {
			parities[index] = -1
			continue
		}
		if !metadata.IsValid() {
			parities[index] = -1
			continue
		}
		// Delete marker or zero byte objects take highest parity.
		if metadata.Deleted || metadata.Size == 0 {

        }
    ]
}
```

### 3.3 Automatic removal of delete markers with no other versions

When an object has only one version as a delete marker, the latter can be automatically removed after a certain number of days using the following configuration:

```
{
    "Rules": [
        {
            "ID": "Removing all delete markers",
            "Expiration": {
                "DeleteMarker": true

// By default at least 128 entries in single getdents call (1MiB buffer)
var (
	direntPool = sync.Pool{
		New: func() interface{} {
			buf := make([]byte, blockSize*128)
			return &buf
		},
	}

	direntNamePool = sync.Pool{
		New: func() interface{} {
			buf := make([]byte, blockSize)
			return &buf
		},
	}
)

// unexpectedFileMode is a sentinel (and bogus) os.FileMode

func (s *xlStorage) setDeleteAttribute(deleteCount uint64) error {
	attr := "user.total_deletes"

	data := make([]byte, 8)
	binary.LittleEndian.PutUint64(data, deleteCount)
	return xattr.LSet(s.formatFile, attr, data)
}

func (s *xlStorage) setWriteAttribute(writeCount uint64) error {
	attr := "user.total_writes"

	data := make([]byte, 8)
	binary.LittleEndian.PutUint64(data, writeCount)
	return xattr.LSet(s.formatFile, attr, data)

	if err != nil {
		// invalid worker size.
		return err
	}

	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	results := make(chan ObjectInfo, workerSize)
	if err := api.Walk(ctx, r.Bucket, r.Prefix, results, WalkOptions{
		Marker:       lastObject,
		LatestOnly:   false, // we need to visit all versions of the object to implement purge: retainVersions
		VersionsSort: WalkVersionsSortDesc,