```

### Using xl-meta

## Description of `xl.meta`

`xl.meta` is a new self describing backend format used by MinIO to support AWS S3 compatible versioning.
This file is the source of truth for each `version` at rest. `xl.meta` is a msgpack file serialized from a
well defined data structure. To understand `xl.meta` here are the few things to start with

//go:generate msgp -file=$GOFILE -unexported

// A xlMetaV1Object represents `xl.meta` metadata header.
type xlMetaV1Object struct {
	Version string   `json:"version"` // Version of the current `xl.meta`.
	Format  string   `json:"format"`  // Format of the current `xl.meta`.
	Stat    StatInfo `json:"stat"`    // Stat of the current object `xl.meta`.
	// Erasure coded info for the current object `xl.meta`.
	Erasure ErasureInfo `json:"erasure"`

		}
		if len(meta.metadata) == 0 {
			metaDataPoolPut(meta.metadata)
			meta.metadata = nil
		}
		if !inclDirs && (meta.isDir() || (!inclVersions && meta.isObjectDir() && meta.isLatestDeletemarker())) {
			continue
		}
		if !inclDeleted && meta.isLatestDeletemarker() && meta.isObject() && !meta.isObjectDir() {
			continue
		}
		res = append(res, meta)
	}

syntax = "proto2";

package k8s.io.apimachinery.pkg.apis.meta.v1beta1;

import "k8s.io/apimachinery/pkg/apis/meta/v1/generated.proto";
import "k8s.io/apimachinery/pkg/runtime/schema/generated.proto";

// Package-wide variables from generator "generated".
option go_package = "k8s.io/apimachinery/pkg/apis/meta/v1beta1";

// PartialObjectMetadataList contains a list of objects containing only their metadata.

					// such scenarios the 'xl.meta' might get truncated
					if !IsErrIgnored(err, io.EOF, io.ErrUnexpectedEOF) {
						internalLogOnceIf(ctx, err, "metacache-walk-read-metadata")
					}
					continue
				}
				meta.name = strings.TrimSuffix(entry, xlStorageFormatFile)
				meta.name = strings.TrimSuffix(meta.name, SlashSeparator)
				meta.name = pathJoinBuf(sb, current, meta.name)
				meta.name = decodeDirObject(meta.name)

coverage.txt
.vscode/
*.tar.bz2
parts/
prime/
stage/
.sia_temp/
config.json
node_modules/
mc.*
s3-check-md5*
xl-meta*
healing-*
inspect*.zip
200M*
hash-set
minio.RELEASE*
mc
nancy
inspects/*
.bin/
*.gz
docs/debugging/s3-verify/s3-verify
docs/debugging/xl-meta/xl-meta
docs/debugging/s3-check-md5/s3-check-md5
docs/debugging/hash-set/hash-set
docs/debugging/healing-bin/healing-bin

			if !meta.Deleted && meta.Size != 0 {
				fmt.Fprintf(h, "%v+%v", meta.Erasure.DataBlocks, meta.Erasure.ParityBlocks)
				fmt.Fprintf(h, "%v", meta.Erasure.Distribution)
			}

			if meta.IsRemote() {
				// ILM transition fields
				fmt.Fprint(h, meta.TransitionStatus)
				fmt.Fprint(h, meta.TransitionTier)
				fmt.Fprint(h, meta.TransitionedObjName)

		name           string
	}{
		{
			meta:           meta,
			pools:          pools,
			name:           "Correct",
			expectedErr:    false,
			expectedUpdate: false,
		},
		{
			meta:           meta,
			pools:          newPools,
			name:           "Correct-Update",
			expectedErr:    false,
			expectedUpdate: true,
		},
		{
			meta:           meta,
			pools:          reducedPools,

		{
			header: http.Header{
				"X-Amz-Meta-Appid":   []string{"amz-meta"},
				"X-Minio-Meta-Appid": []string{"minio-meta"},
			},
			metadata: map[string]string{
				"X-Amz-Meta-Appid":   "amz-meta",
				"X-Minio-Meta-Appid": "minio-meta",
			},
			shouldFail: false,
		},
		// Fail if header key is not in canonicalized form
		{
			header: http.Header{
				"x-amz-meta-appid": []string{"amz-meta"},
			},