fix(replication): apply bucket metadata source times under the metadata lock

Signed-off-by: Feng Ruohang <rh@vonng.com>

cmd/admin-bucket-handlers.go

@@ -76,7 +76,7 @@ func (a adminAPIHandlers) PutBucketQuotaConfigHandler(w http.ResponseWriter, r *
 		return
 	}
 
-	quotaConfig, err := parseBucketQuota(bucket, data)
+	_, err = parseBucketQuota(bucket, data)
 	if err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return
@@ -94,9 +94,6 @@ func (a adminAPIHandlers) PutBucketQuotaConfigHandler(w http.ResponseWriter, r *
 		Quota:     data,
 		UpdatedAt: updatedAt,
 	}
-	if quotaConfig.Size == 0 && quotaConfig.Quota == 0 {
-		bucketMeta.Quota = nil
-	}
 
 	// Call site replication hook.
 	replLogIf(ctx, globalSiteReplicationSys.BucketMetaHook(ctx, bucketMeta))
@@ -922,7 +919,7 @@ func (a adminAPIHandlers) ImportBucketMetadataHandler(w http.ResponseWriter, r *
 				continue
 			}
 
-			configData, err := json.Marshal(bucketPolicy)
+			configData, err := canonicalBucketPolicy(bucketPolicy)
 			if err != nil {
 				rpt.SetStatus(bucket, fileName, err)
 				continue
@@ -1081,18 +1078,39 @@ func (a adminAPIHandlers) ImportBucketMetadataHandler(w http.ResponseWriter, r *
 			continue
 		}
 		var merged BucketMetadata
+		var commitAt time.Time
 		err := func() error {
 			lockCtx, unlock, err := lockBucketMetadata(ctx, objectAPI, bucket)
 			if err != nil {
 				return err
 			}
 			defer unlock()
-			merged, err = loadBucketMetadataParse(lockCtx, objectAPI, bucket, true)
+			merged, err = loadBucketMetadataParse(lockCtx, objectAPI, bucket, false)
 			if err != nil {
 				return err
 			}
+			if err := ensureBucketMetadataCreated(lockCtx, objectAPI, &merged); err != nil {
+				return err
+			}
+			commitAt = UTCNow()
+			for _, file := range replicatedBucketConfigs {
+				if _, ok := fields[file]; ok {
+					commitAt = localBucketConfigUpdatedAt(merged, file, commitAt)
+				}
+			}
 			applyImportedBucketMetadata(&merged, *meta, fields)
-			return globalBucketMetadataSys.saveMetadata(lockCtx, objectAPI, merged)
+			for _, file := range replicatedBucketConfigs {
+				if _, ok := fields[file]; !ok {
+					continue
+				}
+				data, at := replicatedBucketConfig(&merged, file)
+				payload, _, err := bucketConfigPayload(bucket, file, *data, len(merged.ObjectLockConfigXML) != 0)
+				if err != nil {
+					return err
+				}
+				*data, *at = payload, commitAt
+			}
+			return globalBucketMetadataSys.saveMetadata(lockCtx, objectAPI, &merged)
 		}()
 		if err != nil {
 			rpt.SetStatus(bucket, "", err)
@@ -1100,7 +1118,7 @@ func (a adminAPIHandlers) ImportBucketMetadataHandler(w http.ResponseWriter, r *
 		}
 		*meta = merged
 		globalNotificationSys.LoadBucketMetadata(bgContext(ctx), bucket)
-		hook := madmin.SRBucketMeta{Bucket: bucket, UpdatedAt: updatedAt}
+		hook := madmin.SRBucketMeta{Bucket: bucket, UpdatedAt: commitAt}
 		var hookNeeded bool
 		if _, ok := fields[bucketQuotaConfigFile]; ok {
 			hook.Quota = meta.QuotaConfigJSON
@@ -1108,7 +1126,7 @@ func (a adminAPIHandlers) ImportBucketMetadataHandler(w http.ResponseWriter, r *
 		}
 		if _, ok := fields[bucketPolicyConfig]; ok {
 			hook.Policy = meta.PolicyConfigJSON
-			hookNeeded = true
+			hookNeeded = hookNeeded || len(hook.Policy) != 0
 		}
 		if _, ok := fields[bucketVersioningConfig]; ok {
 			hook.Versioning = enc(meta.VersioningConfigXML)
@@ -1129,6 +1147,12 @@ func (a adminAPIHandlers) ImportBucketMetadataHandler(w http.ResponseWriter, r *
 		if hookNeeded {
 			err = globalSiteReplicationSys.BucketMetaHook(ctx, hook)
 		}
+		if _, ok := fields[bucketPolicyConfig]; ok && len(meta.PolicyConfigJSON) == 0 {
+			// An omitted bulk Policy cannot express deletion.
+			err = errors.Join(err, globalSiteReplicationSys.BucketMetaHook(ctx, madmin.SRBucketMeta{
+				Type: madmin.SRBucketMetaTypePolicy, Bucket: bucket, UpdatedAt: commitAt,
+			}))
+		}
 		if _, ok := fields[bucketCorsConfig]; ok {
 			// CORS carries its own timestamp, so it replicates through the
 			// dedicated event rather than the shared bucket metadata hook. It

cmd/bucket-metadata-replication.go

@@ -0,0 +1,318 @@
+// Copyright (c) 2015-2026 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 (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"sort"
+	"time"
+
+	"github.com/minio/minio-go/v7/pkg/tags"
+	bucketsse "github.com/minio/minio/internal/bucket/encryption"
+	objectlock "github.com/minio/minio/internal/bucket/object/lock"
+	"github.com/minio/minio/internal/bucket/versioning"
+	"github.com/pgsty/silo-pkg/v3/policy"
+)
+
+// Only these fields share the site-replication source-time ordering contract.
+// Object Lock is applied before Versioning, whose effective document depends on it.
+var replicatedBucketConfigs = [...]string{
+	objectLockConfig, bucketVersioningConfig, bucketPolicyConfig,
+	bucketTaggingConfig, bucketSSEConfig, bucketQuotaConfigFile,
+}
+
+func replicatedBucketConfig(meta *BucketMetadata, file string) (*[]byte, *time.Time) {
+	switch file {
+	case bucketPolicyConfig:
+		return &meta.PolicyConfigJSON, &meta.PolicyConfigUpdatedAt
+	case bucketTaggingConfig:
+		return &meta.TaggingConfigXML, &meta.TaggingConfigUpdatedAt
+	case bucketSSEConfig:
+		return &meta.EncryptionConfigXML, &meta.EncryptionConfigUpdatedAt
+	case bucketQuotaConfigFile:
+		return &meta.QuotaConfigJSON, &meta.QuotaConfigUpdatedAt
+	case bucketVersioningConfig:
+		return &meta.VersioningConfigXML, &meta.VersioningConfigUpdatedAt
+	case objectLockConfig:
+		return &meta.ObjectLockConfigXML, &meta.ObjectLockConfigUpdatedAt
+	}
+	return nil, nil
+}
+
+func bucketConfigUpdateOnly(file string) bool {
+	return file == bucketVersioningConfig || file == objectLockConfig
+}
+
+// Reuse the persistence rule before comparison, so an accepted Versioning
+// event and the document Save actually writes have the same comparison key.
+func effectiveBucketVersioning(data []byte, lockEnabled bool) []byte {
+	if lockEnabled {
+		config, err := versioning.ParseConfig(bytes.NewReader(data))
+		if err != nil || !config.Enabled() || config.PrefixesExcluded() {
+			return enabledBucketVersioningConfig
+		}
+	}
+	return data
+}
+
+// A parsed policy still contains map-backed sets with nondeterministic Marshal
+// order. Sort every set array recursively, including statements and conditions.
+// RawMessage keeps integer values intact; decoding through float64 would not.
+func canonicalBucketPolicyJSON(data json.RawMessage) (json.RawMessage, error) {
+	data = bytes.TrimSpace(data)
+	if len(data) == 0 {
+		return nil, nil
+	}
+	switch data[0] {
+	case '{':
+		var obj map[string]json.RawMessage
+		if err := json.Unmarshal(data, &obj); err != nil {
+			return nil, err
+		}
+		for key, value := range obj {
+			var err error
+			obj[key], err = canonicalBucketPolicyJSON(value)
+			if err != nil {
+				return nil, err
+			}
+		}
+		return json.Marshal(obj)
+	case '[':
+		var arr []json.RawMessage
+		if err := json.Unmarshal(data, &arr); err != nil {
+			return nil, err
+		}
+		for i := range arr {
+			var err error
+			arr[i], err = canonicalBucketPolicyJSON(arr[i])
+			if err != nil {
+				return nil, err
+			}
+		}
+		sort.Slice(arr, func(i, j int) bool { return bytes.Compare(arr[i], arr[j]) < 0 })
+		return json.Marshal(arr)
+	default:
+		var compact bytes.Buffer
+		if err := json.Compact(&compact, data); err != nil {
+			return nil, err
+		}
+		return compact.Bytes(), nil
+	}
+}
+
+// Encode the validated policy fields explicitly: BPStatement's required
+// Action/Resource tags otherwise try to marshal empty sets for the supported
+// NotAction/NotResource alternatives. This stays within the existing schema.
+func canonicalBucketPolicy(cfg *policy.BucketPolicy) ([]byte, error) {
+	if cfg.IsEmpty() {
+		return nil, nil
+	}
+	doc := map[string]any{"Version": cfg.Version}
+	if cfg.ID != "" {
+		doc["ID"] = cfg.ID
+	}
+	statements := make([]map[string]any, 0, len(cfg.Statements))
+	for _, st := range cfg.Statements {
+		statement := map[string]any{"Effect": st.Effect, "Principal": st.Principal}
+		if st.SID != "" {
+			statement["Sid"] = st.SID
+		}
+		if len(st.Actions) != 0 {
+			statement["Action"] = st.Actions
+		}
+		if len(st.NotActions) != 0 {
+			statement["NotAction"] = st.NotActions
+		}
+		if len(st.Resources) != 0 {
+			statement["Resource"] = st.Resources
+		}
+		if len(st.NotResources) != 0 {
+			statement["NotResource"] = st.NotResources
+		}
+		if len(st.Conditions) != 0 {
+			statement["Condition"] = st.Conditions
+		}
+		statements = append(statements, statement)
+	}
+	doc["Statement"] = statements
+	data, err := json.Marshal(doc)
+	if err != nil {
+		return nil, err
+	}
+	return canonicalBucketPolicyJSON(data)
+}
+
+// Validate with the same parsers as Save. Policy's established empty-policy
+// semantics are deletion; a parsed zero quota is still a live document.
+func bucketConfigPayload(bucket, file string, data []byte, lockEnabled bool) ([]byte, []byte, error) {
+	if len(data) == 0 {
+		return nil, nil, nil
+	}
+	var err error
+	key := data
+	switch file {
+	case bucketPolicyConfig:
+		var cfg *policy.BucketPolicy
+		cfg, err = policy.ParseBucketPolicyConfig(bytes.NewReader(data), bucket)
+		if err == nil {
+			if cfg.IsEmpty() {
+				return nil, nil, nil
+			}
+			key, err = canonicalBucketPolicy(cfg)
+		}
+	case bucketQuotaConfigFile:
+		cfg, parseErr := parseBucketQuota(bucket, data)
+		err = parseErr
+		if err == nil {
+			key, err = json.Marshal(cfg)
+		}
+	case bucketTaggingConfig:
+		_, err = tags.ParseBucketXML(bytes.NewReader(data))
+	case bucketSSEConfig:
+		_, err = bucketsse.ParseBucketSSEConfig(bytes.NewReader(data))
+	case objectLockConfig:
+		_, err = objectlock.ParseObjectLockConfig(bytes.NewReader(data))
+	case bucketVersioningConfig:
+		data = effectiveBucketVersioning(data, lockEnabled)
+		key = data
+		_, err = versioning.ParseConfig(bytes.NewReader(data))
+	}
+	return data, key, err
+}
+
+type bucketConfigState struct {
+	data, key   []byte
+	at          time.Time
+	real, valid bool
+}
+
+func newBucketConfigState(bucket, file string, data []byte, at, created time.Time, lockEnabled bool) (bucketConfigState, error) {
+	data, key, err := bucketConfigPayload(bucket, file, data, lockEnabled)
+	if err != nil {
+		return bucketConfigState{}, err
+	}
+	if at.IsZero() {
+		at = created
+	}
+	valid := !created.IsZero() && !at.Before(created)
+	real := valid && at.After(created)
+	if bucketConfigUpdateOnly(file) && len(data) == 0 {
+		real = false
+	}
+	return bucketConfigState{data: data, key: key, at: at, real: real, valid: valid}, nil
+}
+
+func (s bucketConfigState) candidate() bool {
+	return s.valid && (s.real || len(s.data) != 0)
+}
+
+func compareBucketConfigStates(a, b bucketConfigState) int {
+	if a.valid != b.valid {
+		if a.valid {
+			return 1
+		}
+		return -1
+	}
+	if a.real != b.real {
+		if a.real {
+			return 1
+		}
+		return -1
+	}
+	if a.real {
+		if n := a.at.Compare(b.at); n != 0 {
+			return n
+		}
+		// At equal source time a real deletion wins, preventing resurrection.
+		if (len(a.data) == 0) != (len(b.data) == 0) {
+			if len(a.data) == 0 {
+				return 1
+			}
+			return -1
+		}
+	}
+	return bytes.Compare(a.key, b.key)
+}
+
+func localBucketConfigUpdatedAt(meta BucketMetadata, file string, now time.Time) time.Time {
+	_, at := replicatedBucketConfig(&meta, file)
+	for _, lower := range []time.Time{meta.Created, *at} {
+		if !now.After(lower) {
+			now = lower.Add(time.Nanosecond)
+		}
+	}
+	return now.UTC()
+}
+
+func ensureBucketMetadataCreated(ctx context.Context, obj ObjectLayer, meta *BucketMetadata) error {
+	if !meta.Created.IsZero() {
+		return nil
+	}
+	info, err := obj.GetBucketInfo(ctx, meta.Name, BucketOptions{NoMetadata: true})
+	if err != nil {
+		return err
+	}
+	if info.Created.IsZero() {
+		return errors.New("bucket metadata creation time is unknown")
+	}
+	meta.Created = info.Created.UTC()
+	return nil
+}
+
+// applyBucketConfig runs under metadata.lock, on freshly loaded metadata. It
+// changes only the selected field; the caller persists once after all checks.
+func applyBucketConfig(meta *BucketMetadata, file string, data []byte, at time.Time) (bool, error) {
+	if bucketConfigUpdateOnly(file) && len(data) == 0 {
+		return false, nil
+	}
+	current, currentAt := replicatedBucketConfig(meta, file)
+	lockEnabled := len(meta.ObjectLockConfigXML) != 0
+	incoming, err := newBucketConfigState(meta.Name, file, data, at, meta.Created, lockEnabled)
+	if err != nil {
+		return false, err
+	}
+	if !incoming.candidate() {
+		return false, nil
+	}
+	local, err := newBucketConfigState(meta.Name, file, *current, *currentAt, meta.Created, lockEnabled)
+	if err != nil {
+		return false, err
+	}
+	if compareBucketConfigStates(incoming, local) <= 0 {
+		return false, nil
+	}
+	*current, *currentAt = bytes.Clone(incoming.data), incoming.at.UTC()
+	return true, nil
+}
+
+func rebaseBucketConfigDefaults(meta *BucketMetadata, oldCreated time.Time) {
+	if meta.Created.Equal(oldCreated) {
+		return
+	}
+	// These six fields alone use Created to distinguish a baseline from a
+	// tombstone. Preserve actual source times when adopting an existing bucket.
+	for _, file := range replicatedBucketConfigs {
+		_, at := replicatedBucketConfig(meta, file)
+		if at.IsZero() || at.Equal(oldCreated) {
+			*at = meta.Created
+		}
+	}
+}

cmd/bucket-metadata-sys.go

@@ -126,19 +126,38 @@ func (sys *BucketMetadataSys) Set(bucket string, meta BucketMetadata) {
 	}
 }
 
-func (sys *BucketMetadataSys) updateAndParse(ctx context.Context, bucket string, configFile string, configData []byte, parse, lifecycleDelete bool) (updatedAt time.Time, err error) {
+type bucketMetadataUpdate struct {
+	meta      BucketMetadata
+	updatedAt time.Time
+	changed   bool
+}
+
+func (sys *BucketMetadataSys) updateAndParse(ctx context.Context, bucket, configFile string, configData []byte, parse, lifecycleDelete bool) (time.Time, error) {
+	result, err := sys.updateAndParseMetadata(ctx, bucket, configFile, configData, parse, lifecycleDelete, nil)
+	return result.updatedAt, err
+}
+
+func (sys *BucketMetadataSys) updateAndParseMetadata(ctx context.Context, bucket string, configFile string, configData []byte, parse, lifecycleDelete bool, sourceTime *time.Time) (result bucketMetadataUpdate, err error) {
 	objAPI := newObjectLayerFn()
 	if objAPI == nil {
-		return updatedAt, errServerNotInitialized
+		return result, errServerNotInitialized
 	}
 
 	if isMinioMetaBucketName(bucket) {
-		return updatedAt, errInvalidArgument
+		return result, errInvalidArgument
+	}
+	// Load deletions without parsed caches (notably quota), and compare the
+	// six replicated fields against the raw document under the same lock.
+	if data, _ := replicatedBucketConfig(&result.meta, configFile); data != nil {
+		parse = false
+		if bucketConfigUpdateOnly(configFile) && len(configData) == 0 {
+			return result, nil
+		}
 	}
 	notifyCtx := ctx
 	ctx, unlock, err := lockBucketMetadata(ctx, objAPI, bucket)
 	if err != nil {
-		return updatedAt, err
+		return result, err
 	}
 
 	err = func() error {
@@ -158,55 +177,61 @@ func (sys *BucketMetadataSys) updateAndParse(ctx context.Context, bucket string,
 				return err
 			}
 		}
-		updatedAt = UTCNow()
-		switch configFile {
-		case bucketPolicyConfig:
-			meta.PolicyConfigJSON = configData
-			meta.PolicyConfigUpdatedAt = updatedAt
-		case bucketNotificationConfig:
-			meta.NotificationConfigXML = configData
-			meta.NotificationConfigUpdatedAt = updatedAt
-		case bucketLifecycleConfig:
-			meta.LifecycleConfigXML = configData
-			meta.LifecycleConfigUpdatedAt = updatedAt
-		case bucketSSEConfig:
-			meta.EncryptionConfigXML = configData
-			meta.EncryptionConfigUpdatedAt = updatedAt
-		case bucketTaggingConfig:
-			meta.TaggingConfigXML = configData
-			meta.TaggingConfigUpdatedAt = updatedAt
-		case bucketQuotaConfigFile:
-			meta.QuotaConfigJSON = configData
-			meta.QuotaConfigUpdatedAt = updatedAt
-		case objectLockConfig:
-			meta.ObjectLockConfigXML = configData
-			meta.ObjectLockConfigUpdatedAt = updatedAt
-		case bucketVersioningConfig:
-			meta.VersioningConfigXML = configData
-			meta.VersioningConfigUpdatedAt = updatedAt
-		case bucketReplicationConfig:
-			meta.ReplicationConfigXML = configData
-			meta.ReplicationConfigUpdatedAt = updatedAt
-		case bucketTargetsFile:
-			meta.BucketTargetsConfigJSON, meta.BucketTargetsConfigMetaJSON, err = encryptBucketMetadata(ctx, meta.Name, configData, kms.Context{
-				bucket:            meta.Name,
-				bucketTargetsFile: bucketTargetsFile,
-			})
-			if err != nil {
-				return fmt.Errorf("Error encrypting bucket target metadata %w", err)
+		updatedAt := UTCNow()
+		if data, _ := replicatedBucketConfig(&meta, configFile); data != nil {
+			if err := ensureBucketMetadataCreated(ctx, objAPI, &meta); err != nil {
+				return err
+			}
+			if sourceTime == nil || sourceTime.IsZero() {
+				updatedAt = localBucketConfigUpdatedAt(meta, configFile, updatedAt)
+			} else {
+				updatedAt = sourceTime.UTC()
+			}
+			changed, err := applyBucketConfig(&meta, configFile, configData, updatedAt)
+			if err != nil {
+				return err
+			}
+			if !changed {
+				return nil
+			}
+		} else {
+			switch configFile {
+			case bucketNotificationConfig:
+				meta.NotificationConfigXML = configData
+				meta.NotificationConfigUpdatedAt = updatedAt
+			case bucketLifecycleConfig:
+				meta.LifecycleConfigXML = configData
+				meta.LifecycleConfigUpdatedAt = updatedAt
+			case bucketReplicationConfig:
+				meta.ReplicationConfigXML = configData
+				meta.ReplicationConfigUpdatedAt = updatedAt
+			case bucketTargetsFile:
+				meta.BucketTargetsConfigJSON, meta.BucketTargetsConfigMetaJSON, err = encryptBucketMetadata(ctx, meta.Name, configData, kms.Context{
+					bucket:            meta.Name,
+					bucketTargetsFile: bucketTargetsFile,
+				})
+				if err != nil {
+					return fmt.Errorf("Error encrypting bucket target metadata %w", err)
+				}
+				meta.BucketTargetsConfigUpdatedAt = updatedAt
+				meta.BucketTargetsConfigMetaUpdatedAt = updatedAt
+			default:
+				return fmt.Errorf("Unknown bucket %s metadata update requested %s", bucket, configFile)
 			}
-			meta.BucketTargetsConfigUpdatedAt = updatedAt
-			meta.BucketTargetsConfigMetaUpdatedAt = updatedAt
-		default:
-			return fmt.Errorf("Unknown bucket %s metadata update requested %s", bucket, configFile)
 		}
-		return sys.saveMetadata(ctx, objAPI, meta)
+		if err := sys.saveMetadata(ctx, objAPI, &meta); err != nil {
+			return err
+		}
+		result = bucketMetadataUpdate{meta: meta, updatedAt: updatedAt, changed: true}
+		return nil
 	}()
 	if err != nil {
-		return updatedAt, err
+		return result, err
 	}
-	globalNotificationSys.LoadBucketMetadata(bgContext(notifyCtx), bucket) // Do not use caller context here
-	return updatedAt, nil
+	if result.changed {
+		globalNotificationSys.LoadBucketMetadata(bgContext(notifyCtx), bucket)
+	}
+	return result, nil
 }
 
 func (sys *BucketMetadataSys) save(ctx context.Context, meta BucketMetadata) error {
@@ -219,7 +244,7 @@ func (sys *BucketMetadataSys) save(ctx context.Context, meta BucketMetadata) err
 		return errInvalidArgument
 	}
 
-	if err := sys.saveMetadata(ctx, objAPI, meta); err != nil {
+	if err := sys.saveMetadata(ctx, objAPI, &meta); err != nil {
 		return err
 	}
 
@@ -229,7 +254,7 @@ func (sys *BucketMetadataSys) save(ctx context.Context, meta BucketMetadata) err
 
 // saveMetadata persists and publishes metadata locally. Callers performing a
 // read-modify-write must hold metadata.lock and release it before peer fan-out.
-func (sys *BucketMetadataSys) saveMetadata(ctx context.Context, objAPI ObjectLayer, meta BucketMetadata) error {
+func (sys *BucketMetadataSys) saveMetadata(ctx context.Context, objAPI ObjectLayer, meta *BucketMetadata) error {
 	// A writer may have queued for metadata.lock before DeleteBucket completed.
 	// Recheck the physical bucket under that lock, before recreating metadata.
 	if _, err := objAPI.GetBucketInfo(ctx, meta.Name, BucketOptions{NoMetadata: true}); err != nil {
@@ -238,7 +263,7 @@ func (sys *BucketMetadataSys) saveMetadata(ctx context.Context, objAPI ObjectLay
 	if err := meta.Save(ctx, objAPI); err != nil {
 		return err
 	}
-	sys.Set(meta.Name, meta)
+	sys.Set(meta.Name, *meta)
 	return nil
 }
 
@@ -351,7 +376,7 @@ func (sys *BucketMetadataSys) UpdateExpiryLCConfig(ctx context.Context, bucket s
 		}
 		meta.LifecycleConfigXML = configData
 		meta.LifecycleConfigUpdatedAt = UTCNow()
-		return sys.saveMetadata(ctx, objAPI, meta)
+		return sys.saveMetadata(ctx, objAPI, &meta)
 	}()
 	if err != nil {
 		return err

cmd/bucket-metadata.go

@@ -388,15 +388,7 @@ func (b *BucketMetadata) parseAllConfigs(ctx context.Context, objectAPI ObjectLa
 	} else {
 		b.objectLockConfig = nil
 	}
-	if b.objectLockConfig != nil {
-		// Object Lock requires every object to be versioned. Whatever the lock
-		// document contains, a suspended or prefix-excluded versioning document
-		// is replaced by plain Enabled versioning; Save persists the result.
-		config, versioningErr := versioning.ParseConfig(bytes.NewReader(b.VersioningConfigXML))
-		if versioningErr != nil || !config.Enabled() || config.PrefixesExcluded() {
-			b.VersioningConfigXML = enabledBucketVersioningConfig
-		}
-	}
+	b.VersioningConfigXML = effectiveBucketVersioning(b.VersioningConfigXML, b.objectLockConfig != nil)
 
 	if len(b.VersioningConfigXML) != 0 {
 		b.versioningConfig, err = versioning.ParseConfig(bytes.NewReader(b.VersioningConfigXML))

cmd/bucket-policy-handlers.go

@@ -100,13 +100,13 @@ func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *ht
 		return
 	}
 
-	configData, err := json.Marshal(bucketPolicy)
+	configData, err := canonicalBucketPolicy(bucketPolicy)
 	if err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return
 	}
 
-	updatedAt, err := globalBucketMetadataSys.Update(ctx, bucket, bucketPolicyConfig, configData)
+	result, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketPolicyConfig, configData, false, false, nil)
 	if err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return
@@ -116,8 +116,8 @@ func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *ht
 	replLogIf(ctx, globalSiteReplicationSys.BucketMetaHook(ctx, madmin.SRBucketMeta{
 		Type:      madmin.SRBucketMetaTypePolicy,
 		Bucket:    bucket,
-		Policy:    bucketPolicyBytes,
-		UpdatedAt: updatedAt,
+		Policy:    result.meta.PolicyConfigJSON,
+		UpdatedAt: result.updatedAt,
 	}))
 
 	// Success.

cmd/bucket-versioning-handler.go

@@ -97,7 +97,7 @@ func (api objectAPIHandlers) PutBucketVersioningHandler(w http.ResponseWriter, r
 		return
 	}
 
-	updatedAt, err := globalBucketMetadataSys.Update(ctx, bucket, bucketVersioningConfig, configData)
+	result, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketVersioningConfig, configData, false, false, nil)
 	if err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return
@@ -107,12 +107,12 @@ func (api objectAPIHandlers) PutBucketVersioningHandler(w http.ResponseWriter, r
 	//
 	// We encode the xml bytes as base64 to ensure there are no encoding
 	// errors.
-	cfgStr := base64.StdEncoding.EncodeToString(configData)
+	cfgStr := base64.StdEncoding.EncodeToString(result.meta.VersioningConfigXML)
 	replLogIf(ctx, globalSiteReplicationSys.BucketMetaHook(ctx, madmin.SRBucketMeta{
 		Type:       madmin.SRBucketMetaTypeVersionConfig,
 		Bucket:     bucket,
 		Versioning: &cfgStr,
-		UpdatedAt:  updatedAt,
+		UpdatedAt:  result.updatedAt,
 	}))
 
 	writeSuccessResponseHeadersOnly(w)

cmd/site-replication-metadata_test.go

@@ -0,0 +1,624 @@
+// Copyright (c) 2015-2026 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 (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"path"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/minio/madmin-go/v3"
+	"github.com/minio/minio/internal/auth"
+)
+
+func TestPeerBucketMetadataSourceTimeAndDeletion(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: testPeerBucketMetadataSourceTimeAndDeletion})
+}
+
+func testPeerBucketMetadataSourceTimeAndDeletion(obj ObjectLayer, backend, bucket string, _ http.Handler, cred auth.Credentials, t *testing.T) {
+	ctx := t.Context()
+	created := UTCNow().Add(-time.Hour)
+	putAt := created.Add(10 * time.Minute)
+	delAt := putAt.Add(time.Minute)
+	enc := func(s string) *string { v := base64.StdEncoding.EncodeToString([]byte(s)); return &v }
+	base := newBucketMetadata(bucket)
+	base.SetCreatedAt(created)
+	base.defaultTimestamps()
+	quotaJSON, err := json.Marshal(madmin.BucketQuota{Quota: 1024, Type: madmin.HardQuota})
+	if err != nil {
+		t.Fatal(err)
+	}
+	cases := []struct {
+		name, file string
+		put        madmin.SRBucketMeta
+		value      func(BucketMetadata) []byte
+		stamp      func(BucketMetadata) time.Time
+		exported   func(madmin.SRBucketInfo) time.Time
+		deletable  bool
+	}{
+		{"policy", bucketPolicyConfig, madmin.SRBucketMeta{Type: madmin.SRBucketMetaTypePolicy, Policy: []byte(fmt.Sprintf(`{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":"*","Action":"s3:GetObject","Resource":"arn:aws:s3:::%s/*"}]}`, bucket))}, func(m BucketMetadata) []byte { return m.PolicyConfigJSON }, func(m BucketMetadata) time.Time { return m.PolicyConfigUpdatedAt }, func(m madmin.SRBucketInfo) time.Time { return m.PolicyUpdatedAt }, true},
+		{"tags", bucketTaggingConfig, madmin.SRBucketMeta{Type: madmin.SRBucketMetaTypeTags, Tags: enc(`<Tagging><TagSet><Tag><Key>key</Key><Value>old</Value></Tag></TagSet></Tagging>`)}, func(m BucketMetadata) []byte { return m.TaggingConfigXML }, func(m BucketMetadata) time.Time { return m.TaggingConfigUpdatedAt }, func(m madmin.SRBucketInfo) time.Time { return m.TagConfigUpdatedAt }, true},
+		{"sse", bucketSSEConfig, madmin.SRBucketMeta{Type: madmin.SRBucketMetaTypeSSEConfig, SSEConfig: enc(`<ServerSideEncryptionConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`)}, func(m BucketMetadata) []byte { return m.EncryptionConfigXML }, func(m BucketMetadata) time.Time { return m.EncryptionConfigUpdatedAt }, func(m madmin.SRBucketInfo) time.Time { return m.SSEConfigUpdatedAt }, true},
+		{"quota", bucketQuotaConfigFile, madmin.SRBucketMeta{Type: madmin.SRBucketMetaTypeQuotaConfig, Quota: quotaJSON}, func(m BucketMetadata) []byte { return m.QuotaConfigJSON }, func(m BucketMetadata) time.Time { return m.QuotaConfigUpdatedAt }, func(m madmin.SRBucketInfo) time.Time { return m.QuotaConfigUpdatedAt }, true},
+		{"versioning", bucketVersioningConfig, madmin.SRBucketMeta{Type: madmin.SRBucketMetaTypeVersionConfig, Versioning: enc(`<VersioningConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>Enabled</Status></VersioningConfiguration>`)}, func(m BucketMetadata) []byte { return m.VersioningConfigXML }, func(m BucketMetadata) time.Time { return m.VersioningConfigUpdatedAt }, nil, false},
+		{"objectlock", objectLockConfig, newSRBucketObjectLockMeta(bucket, enc(`<ObjectLockConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><ObjectLockEnabled>Enabled</ObjectLockEnabled><Rule><DefaultRetention><Mode>GOVERNANCE</Mode><Days>30</Days></DefaultRetention></Rule></ObjectLockConfiguration>`), putAt), func(m BucketMetadata) []byte { return m.ObjectLockConfigXML }, func(m BucketMetadata) time.Time { return m.ObjectLockConfigUpdatedAt }, nil, false},
+	}
+	for _, tc := range cases {
+		t.Run(backend+"/"+tc.name, func(t *testing.T) {
+			if err := globalBucketMetadataSys.save(ctx, base); err != nil {
+				t.Fatal(err)
+			}
+			item := tc.put
+			item.Bucket, item.UpdatedAt = bucket, putAt
+			apply := func(item madmin.SRBucketMeta) {
+				t.Helper()
+				rec := applySRBucketMetaViaAdmin(t, cred, item)
+				if rec.Code != http.StatusOK {
+					t.Fatalf("admin apply returned %d: %s", rec.Code, rec.Body.String())
+				}
+			}
+			read := func() BucketMetadata {
+				t.Helper()
+				m, err := loadBucketMetadata(ctx, obj, bucket)
+				if err != nil {
+					t.Fatal(err)
+				}
+				return m
+			}
+			apply(item)
+			put := read()
+			if len(tc.value(put)) == 0 {
+				t.Fatal("PUT did not establish live config")
+			}
+			if !tc.stamp(put).Equal(putAt) {
+				t.Errorf("SOURCE_TIME: persisted %s, want source %s", tc.stamp(put), putAt)
+			}
+			apply(madmin.SRBucketMeta{Type: item.Type, Bucket: bucket, UpdatedAt: delAt})
+			after := read()
+			if !tc.deletable {
+				if !bytes.Equal(tc.value(put), tc.value(after)) || !tc.stamp(put).Equal(tc.stamp(after)) {
+					t.Error("NIL_NOOP: update-only config changed")
+				}
+				t.Log("nil payload is correctly a no-op")
+				return
+			}
+			if len(tc.value(after)) != 0 {
+				t.Error("NEWER_DELETE: HTTP 200, but live config remained after newer source DELETE")
+			}
+			if _, err := globalBucketMetadataSys.Delete(ctx, bucket, tc.file); err != nil {
+				t.Fatal(err)
+			}
+			tombstone := read()
+			if len(tc.value(tombstone)) != 0 {
+				t.Fatal("local DELETE failed to establish tombstone")
+			}
+			apply(item)
+			after = read()
+			if len(tc.value(after)) != 0 {
+				t.Error("STALE_RESURRECTION: older source PUT resurrected a locally deleted config")
+			} else {
+				t.Log("older source PUT did not resurrect config")
+			}
+		})
+	}
+}
+
+func TestPeerBucketMetadataBulkOrdering(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: func(obj ObjectLayer, backend, bucket string, _ http.Handler, cred auth.Credentials, t *testing.T) {
+		t.Run(backend, func(t *testing.T) {
+			ctx := t.Context()
+			meta, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			newAt := meta.Created.Add(time.Hour)
+			newXML := `<Tagging><TagSet><Tag><Key>key</Key><Value>new</Value></Tag></TagSet></Tagging>`
+			meta.TaggingConfigXML, meta.TaggingConfigUpdatedAt = []byte(newXML), newAt
+			if err := globalBucketMetadataSys.save(ctx, meta); err != nil {
+				t.Fatal(err)
+			}
+			oldXML := base64.StdEncoding.EncodeToString([]byte(`<Tagging><TagSet><Tag><Key>key</Key><Value>old</Value></Tag></TagSet></Tagging>`))
+			item := madmin.SRBucketMeta{Bucket: bucket, Tags: &oldXML, UpdatedAt: newAt.Add(-time.Minute)}
+			rec := applySRBucketMetaViaAdmin(t, cred, item)
+			if rec.Code != http.StatusOK {
+				t.Fatalf("bulk apply returned %d: %s", rec.Code, rec.Body.String())
+			}
+			after, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !bytes.Equal(after.TaggingConfigXML, []byte(newXML)) || !after.TaggingConfigUpdatedAt.Equal(newAt) {
+				t.Errorf("BULK_STALE_OVERWRITE: older bulk event overwrote newer config, value=%q time=%s", after.TaggingConfigXML, after.TaggingConfigUpdatedAt)
+			}
+		})
+	}})
+}
+
+func TestPeerBucketMetadataOrderingUnderLock(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: func(obj ObjectLayer, backend, bucket string, _ http.Handler, _ auth.Credentials, t *testing.T) {
+		t.Run(backend, func(t *testing.T) {
+			ctx := t.Context()
+			meta, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			oldAt, newAt := meta.Created.Add(time.Hour), meta.Created.Add(2*time.Hour)
+			oldXML := base64.StdEncoding.EncodeToString([]byte(`<Tagging><TagSet><Tag><Key>key</Key><Value>older</Value></Tag></TagSet></Tagging>`))
+			newXML := []byte(`<Tagging><TagSet><Tag><Key>key</Key><Value>newest</Value></Tag></TagSet></Tagging>`)
+			lockCtx, unlock, err := lockBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			locked := true
+			defer func() {
+				if locked {
+					unlock()
+				}
+			}()
+			ready := make(chan struct{}, 1)
+			hook := func(name string) {
+				if name == bucket {
+					select {
+					case ready <- struct{}{}:
+					default:
+					}
+				}
+			}
+			lockBucketMetadataAcquireHook.Store(&hook)
+			defer lockBucketMetadataAcquireHook.Store(nil)
+			done := make(chan error, 1)
+			go func() { done <- globalSiteReplicationSys.PeerBucketTaggingHandler(ctx, bucket, &oldXML, oldAt) }()
+			select {
+			case <-ready:
+			case <-time.After(5 * time.Second):
+				t.Fatal("older event never reached metadata lock")
+			}
+			// A newer writer commits while holding the existing metadata lock.
+			// The old peer event has already checked the pre-commit cache.
+			meta.TaggingConfigXML, meta.TaggingConfigUpdatedAt = newXML, newAt
+			if err := globalBucketMetadataSys.saveMetadata(lockCtx, obj, &meta); err != nil {
+				t.Fatal(err)
+			}
+			unlock()
+			locked = false
+			select {
+			case err := <-done:
+				if err != nil {
+					t.Fatal(err)
+				}
+			case <-time.After(5 * time.Second):
+				t.Fatal("older event did not finish")
+			}
+			after, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if string(after.TaggingConfigXML) != string(newXML) {
+				t.Errorf("CHECK_OUTSIDE_LOCK: queued older event replaced newer committed tags with %q", after.TaggingConfigXML)
+			}
+		})
+	}})
+}
+
+// Count actual metadata persistence, including writes that would be invisible
+// in a value-only assertion after a duplicate or rejected event.
+type bucketConfigWriteCounter struct {
+	ObjectLayer
+	writes atomic.Int64
+}
+
+func (o *bucketConfigWriteCounter) PutObject(ctx context.Context, bucket, object string, data *PutObjReader, opts ObjectOptions) (ObjectInfo, error) {
+	if bucket == minioMetaBucket && path.Base(object) == bucketMetadataFile {
+		o.writes.Add(1)
+	}
+	return o.ObjectLayer.PutObject(ctx, bucket, object, data, opts)
+}
+
+func TestBucketConfigStateOrdering(t *testing.T) {
+	created := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
+	live := []byte(`<Tagging><TagSet><Tag><Key>k</Key><Value>a</Value></Tag></TagSet></Tagging>`)
+	other := bytes.ReplaceAll(live, []byte("<Value>a"), []byte("<Value>b"))
+	state := func(data []byte, at, birth time.Time) bucketConfigState {
+		t.Helper()
+		s, err := newBucketConfigState("bucket", bucketTaggingConfig, data, at, birth, false)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return s
+	}
+	baseline := state(nil, created, created)
+	baselineLive := state(live, created, created)
+	put := state(live, created.Add(time.Second), created)
+	deleted := state(nil, put.at, created)
+	lateBaseline := state(other, created.Add(time.Hour), created.Add(time.Hour))
+	tests := []struct {
+		name          string
+		lower, higher bucketConfigState
+	}{
+		{"baseline initialization", baseline, baselineLive},
+		{"real before later baseline", lateBaseline, put},
+		{"delete wins tie", put, deleted},
+		{"live key tie", put, state(other, put.at, created)},
+		{"new PUT after deletion", deleted, state(live, put.at.Add(time.Second), created)},
+		{"baseline key ignores creation time", state(live, created.Add(time.Hour), created.Add(time.Hour)), state(other, created, created)},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if compareBucketConfigStates(tc.lower, tc.higher) >= 0 || compareBucketConfigStates(tc.higher, tc.lower) <= 0 {
+				t.Fatal("ordering is not antisymmetric or chose the wrong winner")
+			}
+		})
+	}
+	for _, s := range []bucketConfigState{baseline, state(live, created.Add(-time.Second), created), state(live, created, time.Time{})} {
+		if s.candidate() {
+			t.Fatal("default, pre-creation, or unknown-generation state became a source")
+		}
+	}
+	for _, file := range []string{bucketVersioningConfig, objectLockConfig} {
+		s, err := newBucketConfigState("bucket", file, nil, put.at, created, false)
+		if err != nil || s.candidate() {
+			t.Fatalf("empty update-only candidate: %+v %v", s, err)
+		}
+	}
+}
+
+func TestBucketPolicyReplicationKey(t *testing.T) {
+	// Permute independent set arrays and parse separately, as two sites would.
+	a := []byte(`{"Version":"2012-10-17","Statement":[{"Sid":"one","Effect":"Allow","Principal":{"AWS":["b","a"]},"Action":["s3:GetObject","s3:PutObject"],"Resource":["arn:aws:s3:::bucket/b*","arn:aws:s3:::bucket/a*"],"Condition":{"StringLike":{"s3:prefix":["b*","a*"]}}},{"Sid":"two","Effect":"Deny","Principal":"*","NotAction":["s3:GetObject","s3:PutObject"],"NotResource":["arn:aws:s3:::bucket/d*","arn:aws:s3:::bucket/c*"]}]}`)
+	// Use a condition valid for object actions.
+	a = bytes.ReplaceAll(a, []byte("s3:prefix"), []byte("aws:UserAgent"))
+	b := []byte(`{"Statement":[{"NotResource":["arn:aws:s3:::bucket/c*","arn:aws:s3:::bucket/d*"],"NotAction":["s3:PutObject","s3:GetObject"],"Principal":"*","Effect":"Deny","Sid":"two"},{"Condition":{"StringLike":{"aws:UserAgent":["a*","b*"]}},"Resource":["arn:aws:s3:::bucket/a*","arn:aws:s3:::bucket/b*"],"Action":["s3:PutObject","s3:GetObject"],"Principal":{"AWS":["a","b"]},"Effect":"Allow","Sid":"one"}],"Version":"2012-10-17"}`)
+	_, key, err := bucketConfigPayload("bucket", bucketPolicyConfig, a, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i := range 30 {
+		_, next, err := bucketConfigPayload("bucket", bucketPolicyConfig, b, false)
+		if err != nil || !bytes.Equal(key, next) {
+			t.Fatalf("independent parse %d: %s != %s (%v)", i, key, next, err)
+		}
+	}
+	_, sid, err := bucketConfigPayload("bucket", bucketPolicyConfig, bytes.ReplaceAll(a, []byte(`"one"`), []byte(`"other"`)), false)
+	if err != nil || bytes.Equal(key, sid) {
+		t.Fatalf("Sid difference lost: %v", err)
+	}
+	n, err := canonicalBucketPolicyJSON([]byte(`{"n":[9007199254740993,9007199254740992]}`))
+	if err != nil || string(n) != `{"n":[9007199254740992,9007199254740993]}` {
+		t.Fatalf("integer precision lost: %s %v", n, err)
+	}
+}
+
+func TestPeerBucketMetadataWireAtomicity(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: func(obj ObjectLayer, backend, bucket string, _ http.Handler, cred auth.Credentials, t *testing.T) {
+		t.Run(backend, func(t *testing.T) {
+			ctx := t.Context()
+			meta, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			stamp := meta.Created.Add(time.Hour)
+			policyData := []byte(fmt.Sprintf(`{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":"*","Action":"s3:GetObject","Resource":"arn:aws:s3:::%s/*"}]}`, bucket))
+			meta.PolicyConfigJSON, meta.PolicyConfigUpdatedAt = policyData, stamp
+			meta.QuotaConfigJSON, meta.QuotaConfigUpdatedAt = []byte(`{"quota":1024,"quotatype":"hard"}`), stamp
+			meta.TaggingConfigXML, meta.TaggingConfigUpdatedAt = []byte(`<Tagging><TagSet><Tag><Key>k</Key><Value>a</Value></Tag></TagSet></Tagging>`), stamp
+			if err = globalBucketMetadataSys.save(ctx, meta); err != nil {
+				t.Fatal(err)
+			}
+			counter := &bucketConfigWriteCounter{ObjectLayer: obj}
+			setObjectLayer(counter)
+			defer setObjectLayer(obj)
+			read := func() BucketMetadata {
+				t.Helper()
+				m, err := loadBucketMetadata(ctx, obj, bucket)
+				if err != nil {
+					t.Fatal(err)
+				}
+				return m
+			}
+			apply := func(fragment string, at time.Time, ok bool) {
+				t.Helper()
+				raw := fmt.Sprintf(`{"bucket":%q,"updatedAt":%q,%s}`, bucket, at.Format(time.RFC3339Nano), fragment)
+				var item madmin.SRBucketMeta
+				if err := json.Unmarshal([]byte(raw), &item); err != nil {
+					t.Fatal(err)
+				}
+				rec := applySRBucketMetaViaAdmin(t, cred, item)
+				if (rec.Code == http.StatusOK) != ok {
+					t.Fatalf("%s: %d %s", raw, rec.Code, rec.Body.String())
+				}
+			}
+			// Omitted/null *string and empty update-only payloads are all no-ops.
+			apply(`"policy":null,"quota":null,"tags":null,"versioningConfig":"","objectLockConfig":""`, stamp.Add(time.Minute), true)
+			current := read()
+			if len(current.PolicyConfigJSON) != 0 || len(current.QuotaConfigJSON) == 0 {
+				t.Fatal("explicit null semantics lost")
+			}
+			if q, _, err := globalBucketMetadataSys.GetQuotaConfig(ctx, bucket); err != nil || q.Quota != 0 {
+				t.Fatalf("zero quota cache: %+v %v", q, err)
+			}
+			before := counter.writes.Load()
+			apply(`"tags":null,"versioningConfig":"","objectLockConfig":""`, stamp.Add(2*time.Minute), true)
+			if counter.writes.Load() != before {
+				t.Fatal("omitted fields or empty update-only wrote metadata")
+			}
+			// An invalid second field cannot persist the valid deletion in this bulk.
+			apply(`"tags":"","quota":{"quota":1,"quotatype":"invalid"}`, stamp.Add(2*time.Minute), false)
+			if counter.writes.Load() != before || len(read().TaggingConfigXML) == 0 {
+				t.Fatal("invalid bulk partially committed")
+			}
+			apply(`"tags":""`, stamp.Add(2*time.Minute), true)
+			before = counter.writes.Load()
+			apply(`"tags":""`, stamp.Add(2*time.Minute), true)
+			apply(`"tags":""`, stamp.Add(time.Minute), true)
+			if counter.writes.Load() != before {
+				t.Fatal("duplicate or old event wrote metadata")
+			}
+			localAt, err := globalBucketMetadataSys.Update(ctx, bucket, bucketQuotaConfigFile, []byte(`{}`))
+			if err != nil || !localAt.After(current.QuotaConfigUpdatedAt) {
+				t.Fatalf("local future monotonic time: %v %v", localAt, err)
+			}
+			deletedAt, err := globalBucketMetadataSys.Delete(ctx, bucket, bucketQuotaConfigFile)
+			if err != nil || !deletedAt.After(localAt) {
+				t.Fatalf("adjacent local time: %v %v", deletedAt, err)
+			}
+			if q, _, err := globalBucketMetadataSys.GetQuotaConfig(ctx, bucket); err != nil || q.Quota != 0 {
+				t.Fatalf("deleted quota cache: %+v %v", q, err)
+			}
+		})
+	}})
+}
+
+func TestPeerBucketAdoptionRebasesOnlyDefaults(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: func(obj ObjectLayer, backend, bucket string, _ http.Handler, _ auth.Credentials, t *testing.T) {
+		for _, shift := range []time.Duration{-time.Hour, 0, time.Hour} {
+			t.Run(fmt.Sprintf("%s/%s", backend, shift), func(t *testing.T) {
+				created := UTCNow().Add(-3 * time.Hour)
+				meta := newBucketMetadata(bucket)
+				meta.Created = created
+				meta.defaultTimestamps()
+				meta.QuotaConfigUpdatedAt = time.Time{}
+				meta.TaggingConfigUpdatedAt = created.Add(2 * time.Hour) // real deletion
+				meta.EncryptionConfigXML = []byte(`<ServerSideEncryptionConfiguration><Rule><ApplyServerSideEncryptionByDefault><SSEAlgorithm>AES256</SSEAlgorithm></ApplyServerSideEncryptionByDefault></Rule></ServerSideEncryptionConfiguration>`)
+				meta.EncryptionConfigUpdatedAt = created.Add(2 * time.Hour)
+				if err := globalBucketMetadataSys.save(t.Context(), meta); err != nil {
+					t.Fatal(err)
+				}
+				if err := globalSiteReplicationSys.PeerBucketMakeWithVersioningHandler(t.Context(), bucket, MakeBucketOptions{CreatedAt: created.Add(shift)}); err != nil {
+					t.Fatal(err)
+				}
+				got, err := readBucketMetadata(t.Context(), obj, bucket)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if !got.PolicyConfigUpdatedAt.Equal(got.Created) || !got.QuotaConfigUpdatedAt.Equal(got.Created) {
+					t.Fatal("default turned into tombstone or invalid source")
+				}
+				if !got.TaggingConfigUpdatedAt.Equal(meta.TaggingConfigUpdatedAt) || !got.EncryptionConfigUpdatedAt.Equal(meta.EncryptionConfigUpdatedAt) || !bytes.Equal(got.EncryptionConfigXML, meta.EncryptionConfigXML) {
+					t.Fatal("actual state changed during adoption")
+				}
+			})
+		}
+	}})
+}
+
+func recordBucketConfigPeer(t *testing.T, cred auth.Credentials) func() []madmin.SRBucketMeta {
+	t.Helper()
+	var mu sync.Mutex
+	var events []madmin.SRBucketMeta
+	remote := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var event madmin.SRBucketMeta
+		if err := json.NewDecoder(r.Body).Decode(&event); err != nil {
+			t.Error(err)
+			w.WriteHeader(http.StatusBadRequest)
+			return
+		}
+		mu.Lock()
+		events = append(events, event)
+		mu.Unlock()
+		w.WriteHeader(http.StatusOK)
+	}))
+	t.Cleanup(remote.Close)
+	serviceCred, err := auth.CreateCredentials("metadata-source-time-svc", "metadata-source-time-service-secret")
+	if err != nil {
+		t.Fatal(err)
+	}
+	serviceCred.ParentUser = cred.AccessKey
+	globalSiteReplicatorCred.Set(serviceCred.SecretKey)
+	t.Cleanup(func() { globalSiteReplicatorCred.Set("") })
+	if _, err = globalIAMSys.store.AddServiceAccount(t.Context(), serviceCred); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { globalIAMSys.DeleteServiceAccount(context.Background(), serviceCred.AccessKey, false) })
+	globalSiteReplicationSys.Lock()
+	oldEnabled, oldState := globalSiteReplicationSys.enabled, globalSiteReplicationSys.state
+	globalSiteReplicationSys.enabled = true
+	globalSiteReplicationSys.state = srState{Name: "metadata-source-test", ServiceAccountAccessKey: serviceCred.AccessKey, Peers: map[string]madmin.PeerInfo{
+		globalDeploymentID(): {Name: "local", DeploymentID: globalDeploymentID()},
+		"metadata-peer":      {Name: "remote", DeploymentID: "metadata-peer", Endpoint: remote.URL},
+	}}
+	globalSiteReplicationSys.Unlock()
+	t.Cleanup(func() {
+		globalSiteReplicationSys.Lock()
+		globalSiteReplicationSys.enabled, globalSiteReplicationSys.state = oldEnabled, oldState
+		globalSiteReplicationSys.Unlock()
+	})
+	return func() []madmin.SRBucketMeta {
+		mu.Lock()
+		defer mu.Unlock()
+		return append([]madmin.SRBucketMeta(nil), events...)
+	}
+}
+
+// The final metadata lock is taken after reading the ZIP. Commit another
+// writer immediately before that acquisition, using the existing lock wrapper.
+type importInterleavingObjectLayer struct {
+	ObjectLayer
+	once  atomic.Bool
+	write func()
+}
+
+func (o *importInterleavingObjectLayer) NewNSLock(bucket string, objects ...string) RWLocker {
+	lock := o.ObjectLayer.NewNSLock(bucket, objects...)
+	if bucket != minioMetaBucket || len(objects) != 1 || path.Base(objects[0]) != "metadata.lock" {
+		return lock
+	}
+	return metadataObservedRWLocker{RWLocker: lock, onLock: func(context.Context) {
+		if o.once.CompareAndSwap(false, true) {
+			o.write()
+		}
+	}}
+}
+
+func TestLocalBucketMetadataCommittedEvents(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, endpoints: []string{"PutBucketPolicy", "GetBucketPolicy", "PutBucketVersioning"}, objAPITest: func(obj ObjectLayer, backend, bucket string, router http.Handler, cred auth.Credentials, t *testing.T) {
+		t.Run(backend, func(t *testing.T) {
+			ctx := t.Context()
+			events := recordBucketConfigPeer(t, cred)
+			putPolicy := func(data []byte) {
+				t.Helper()
+				req, err := newTestSignedRequestV4(http.MethodPut, getPutPolicyURL("", bucket), int64(len(data)), bytes.NewReader(data), cred.AccessKey, cred.SecretKey, nil)
+				if err != nil {
+					t.Fatal(err)
+				}
+				rec := httptest.NewRecorder()
+				router.ServeHTTP(rec, req)
+				if rec.Code != http.StatusNoContent {
+					t.Fatalf("empty policy PUT: %d %s", rec.Code, rec.Body.String())
+				}
+			}
+			putPolicy([]byte(`{"Version":"2012-10-17","Statement":[]}`))
+			meta, err := loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got := events()
+			if len(got) != 1 || got[0].Type != madmin.SRBucketMetaTypePolicy || len(got[0].Policy) != 0 || len(meta.PolicyConfigJSON) != 0 || !meta.PolicyConfigUpdatedAt.Equal(got[0].UpdatedAt) {
+				t.Fatalf("empty policy event/disk mismatch: %+v", got)
+			}
+			req, err := newTestSignedRequestV4(http.MethodGet, getGetPolicyURL("", bucket), 0, nil, cred.AccessKey, cred.SecretKey, nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+			rec := httptest.NewRecorder()
+			router.ServeHTTP(rec, req)
+			if rec.Code != http.StatusNotFound {
+				t.Fatalf("empty policy GET: %d %s", rec.Code, rec.Body.String())
+			}
+			corsAdminRequest(t, cred, http.MethodPut, "/set-bucket-quota?bucket="+bucket, []byte(`{}`))
+			meta, err = loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got = events()
+			last := got[len(got)-1]
+			if last.Type != madmin.SRBucketMetaTypeQuotaConfig || len(last.Quota) == 0 || !last.UpdatedAt.Equal(meta.QuotaConfigUpdatedAt) {
+				t.Fatalf("zero quota event: %+v", last)
+			}
+
+			injectedAt := UTCNow().Add(2 * time.Hour)
+			interleaving := &importInterleavingObjectLayer{ObjectLayer: obj, write: func() {
+				data := []byte(`{"quota":2048,"quotatype":"hard"}`)
+				_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketQuotaConfigFile, data, false, false, &injectedAt)
+				if err != nil {
+					t.Error(err)
+				}
+			}}
+			setObjectLayer(interleaving)
+			defer setObjectLayer(obj)
+			before := len(events())
+			rec = corsAdminRequest(t, cred, http.MethodPut, "/import-bucket-metadata", corsZip(t, map[string][]byte{
+				bucket + "/" + bucketPolicyConfig:  []byte(`{"Version":"2012-10-17","Statement":[]}`),
+				bucket + "/quota.json":             []byte(`{}`),
+				bucket + "/" + bucketTaggingConfig: []byte(`<Tagging><TagSet><Tag><Key>imported</Key><Value>yes</Value></Tag></TagSet></Tagging>`),
+			}))
+			report := corsImportReport(t, rec).Buckets[bucket]
+			if report.Err != "" || report.Policy.Err != "" || report.Quota.Err != "" || report.Tagging.Err != "" {
+				t.Fatalf("import: %+v", report)
+			}
+			meta, err = loadBucketMetadata(ctx, obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !meta.QuotaConfigUpdatedAt.After(injectedAt) || !meta.TaggingConfigUpdatedAt.Equal(meta.QuotaConfigUpdatedAt) || !meta.PolicyConfigUpdatedAt.Equal(meta.QuotaConfigUpdatedAt) {
+				t.Fatalf("import time %v must exceed intervening %v; policy=%v tags=%v", meta.QuotaConfigUpdatedAt, injectedAt, meta.PolicyConfigUpdatedAt, meta.TaggingConfigUpdatedAt)
+			}
+			got = events()[before:]
+			if len(got) != 2 {
+				t.Fatalf("import events: %+v", got)
+			}
+			for _, event := range got {
+				if !event.UpdatedAt.Equal(meta.QuotaConfigUpdatedAt) {
+					t.Fatal("import hook used ZIP start time")
+				}
+				if event.Type == madmin.SRBucketMetaTypePolicy {
+					if len(event.Policy) != 0 {
+						t.Fatal("empty policy import is not deletion")
+					}
+				} else if event.Tags == nil || len(event.Quota) == 0 {
+					t.Fatalf("bulk omitted imported state: %+v", event)
+				}
+			}
+		})
+	}})
+}
+
+func TestPeerBucketMetadataNormalizesBeforeComparison(t *testing.T) {
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: func(obj ObjectLayer, backend, bucket string, _ http.Handler, cred auth.Credentials, t *testing.T) {
+		t.Run(backend, func(t *testing.T) {
+			meta, err := loadBucketMetadata(t.Context(), obj, bucket)
+			if err != nil {
+				t.Fatal(err)
+			}
+			versioning := base64.StdEncoding.EncodeToString([]byte(`<VersioningConfiguration><Status>Enabled</Status><ExcludedPrefixes><Prefix>skip/</Prefix></ExcludedPrefixes><ExcludeFolders>true</ExcludeFolders></VersioningConfiguration>`))
+			lock := base64.StdEncoding.EncodeToString(enabledBucketObjectLockConfig)
+			item := madmin.SRBucketMeta{Bucket: bucket, ObjectLockConfig: &lock, Versioning: &versioning, UpdatedAt: meta.Created.Add(time.Hour)}
+			counter := &bucketConfigWriteCounter{ObjectLayer: obj}
+			setObjectLayer(counter)
+			defer setObjectLayer(obj)
+			for range 2 {
+				rec := applySRBucketMetaViaAdmin(t, cred, item)
+				if rec.Code != http.StatusOK {
+					t.Fatalf("bulk: %d %s", rec.Code, rec.Body.String())
+				}
+			}
+			if counter.writes.Load() != 1 {
+				t.Fatalf("normalized duplicate persisted %d times", counter.writes.Load())
+			}
+			meta, err = loadBucketMetadata(t.Context(), obj, bucket)
+			if err != nil || !bytes.Equal(meta.VersioningConfigXML, enabledBucketVersioningConfig) || !meta.VersioningConfigUpdatedAt.Equal(item.UpdatedAt) {
+				t.Fatalf("normalization: %s %v", meta.VersioningConfigXML, err)
+			}
+			// Ordinary local updates use the identical effective document in their
+			// commit result, even if Object Lock changed since the handler's precheck.
+			data, _ := base64.StdEncoding.DecodeString(versioning)
+			result, err := globalBucketMetadataSys.updateAndParseMetadata(t.Context(), bucket, bucketVersioningConfig, data, false, false, nil)
+			if err != nil || !bytes.Equal(result.meta.VersioningConfigXML, enabledBucketVersioningConfig) {
+				t.Fatalf("local commit snapshot: %s %v", result.meta.VersioningConfigXML, err)
+			}
+		})
+	}})
+}

cmd/site-replication.go

@@ -906,7 +906,7 @@ func enablePeerBucketVersioning(meta *BucketMetadata, lockEnabled bool) error {
 	config, err := versioning.ParseConfig(bytes.NewReader(meta.VersioningConfigXML))
 	if err != nil || (lockEnabled && (config.Suspended() || config.PrefixesExcluded())) {
 		meta.VersioningConfigXML = enabledBucketVersioningConfig
-		meta.VersioningConfigUpdatedAt = UTCNow()
+		meta.VersioningConfigUpdatedAt = localBucketConfigUpdatedAt(*meta, bucketVersioningConfig, UTCNow())
 		return nil
 	}
 	if config.Enabled() {
@@ -917,7 +917,7 @@ func enablePeerBucketVersioning(meta *BucketMetadata, lockEnabled bool) error {
 	if err != nil {
 		return err
 	}
-	meta.VersioningConfigUpdatedAt = UTCNow()
+	meta.VersioningConfigUpdatedAt = localBucketConfigUpdatedAt(*meta, bucketVersioningConfig, UTCNow())
 	return nil
 }
 
@@ -947,7 +947,9 @@ func (c *SiteReplicationSys) PeerBucketMakeWithVersioningHandler(ctx context.Con
 		if err != nil {
 			return err
 		}
+		oldCreated := meta.Created
 		meta.SetCreatedAt(opts.CreatedAt)
+		rebaseBucketConfigDefaults(&meta, oldCreated)
 
 		if err = enablePeerBucketVersioning(&meta, opts.LockEnabled || len(meta.ObjectLockConfigXML) != 0); err != nil {
 			return err
@@ -958,7 +960,7 @@ func (c *SiteReplicationSys) PeerBucketMakeWithVersioningHandler(ctx context.Con
 				meta.ObjectLockConfigUpdatedAt = meta.Created
 			}
 		}
-		return globalBucketMetadataSys.saveMetadata(bgContext(ctx), objAPI, meta)
+		return globalBucketMetadataSys.saveMetadata(bgContext(ctx), objAPI, &meta)
 	}()
 	if err != nil {
 		return wrapSRErr(c.annotateErr(makeBucketWithVersion, err))
@@ -1583,24 +1585,18 @@ func (c *SiteReplicationSys) BucketMetaHook(ctx context.Context, item madmin.SRB
 
 // PeerBucketVersioningHandler - updates versioning config to local cluster.
 func (c *SiteReplicationSys) PeerBucketVersioningHandler(ctx context.Context, bucket string, versioning *string, updatedAt time.Time) error {
+	var data []byte
 	if versioning != nil {
-		// skip overwrite if local update is newer than peer update.
-		if !updatedAt.IsZero() {
-			if _, updateTm, err := globalBucketMetadataSys.GetVersioningConfig(bucket); err == nil && updateTm.After(updatedAt) {
-				return nil
-			}
-		}
-		configData, err := base64.StdEncoding.DecodeString(*versioning)
+		var err error
+		data, err = base64.StdEncoding.DecodeString(*versioning)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketVersioningConfig, configData)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		return nil
 	}
-
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketVersioningConfig, data, false, false, &updatedAt)
+	if err != nil {
+		return wrapSRErr(err)
+	}
 	return nil
 }
 
@@ -1650,50 +1646,43 @@ func (c *SiteReplicationSys) PeerBucketMetadataUpdateHandler(ctx context.Context
 		return nil
 	}
 
-	if item.Policy != nil {
-		meta.PolicyConfigJSON = item.Policy
-		meta.PolicyConfigUpdatedAt = item.UpdatedAt
+	// Presence is separate from content: omitted RawMessage is not a delete;
+	// explicit JSON null still goes through the existing policy/quota parser.
+	updates := make(map[string][]byte, len(replicatedBucketConfigs))
+	if len(item.Policy) != 0 {
+		updates[bucketPolicyConfig] = item.Policy
 	}
-
-	if item.Versioning != nil {
-		configData, err := base64.StdEncoding.DecodeString(*item.Versioning)
+	if len(item.Quota) != 0 {
+		updates[bucketQuotaConfigFile] = item.Quota
+	}
+	for file, payload := range map[string]*string{
+		objectLockConfig: item.ObjectLockConfig, bucketVersioningConfig: item.Versioning,
+		bucketTaggingConfig: item.Tags, bucketSSEConfig: item.SSEConfig,
+	} {
+		if payload != nil {
+			data, err := base64.StdEncoding.DecodeString(*payload)
+			if err != nil {
+				return wrapSRErr(err)
+			}
+			updates[file] = data
+		}
+	}
+	if len(updates) != 0 {
+		if err := ensureBucketMetadataCreated(ctx, objectAPI, &meta); err != nil {
+			return wrapSRErr(err)
+		}
+	}
+	changed := false
+	for _, file := range replicatedBucketConfigs {
+		data, supplied := updates[file]
+		if !supplied {
+			continue
+		}
+		applied, err := applyBucketConfig(&meta, file, data, item.UpdatedAt)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-		meta.VersioningConfigXML = configData
-		meta.VersioningConfigUpdatedAt = item.UpdatedAt
-	}
-
-	if item.Tags != nil {
-		configData, err := base64.StdEncoding.DecodeString(*item.Tags)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		meta.TaggingConfigXML = configData
-		meta.TaggingConfigUpdatedAt = item.UpdatedAt
-	}
-
-	if item.ObjectLockConfig != nil {
-		configData, err := base64.StdEncoding.DecodeString(*item.ObjectLockConfig)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		meta.ObjectLockConfigXML = configData
-		meta.ObjectLockConfigUpdatedAt = item.UpdatedAt
-	}
-
-	if item.SSEConfig != nil {
-		configData, err := base64.StdEncoding.DecodeString(*item.SSEConfig)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		meta.EncryptionConfigXML = configData
-		meta.EncryptionConfigUpdatedAt = item.UpdatedAt
-	}
-
-	if item.Quota != nil {
-		meta.QuotaConfigJSON = item.Quota
-		meta.QuotaConfigUpdatedAt = item.UpdatedAt
+		changed = changed || applied
 	}
 
 	if item.Cors != nil {
@@ -1702,10 +1691,14 @@ func (c *SiteReplicationSys) PeerBucketMetadataUpdateHandler(ctx context.Context
 		if compareCORSReplicationStates(localState, incoming) < 0 {
 			meta.CorsConfigXML = bytes.Clone(corsConfigData)
 			meta.CorsConfigUpdatedAt = item.UpdatedAt
+			changed = true
 		}
 	}
 
-	if err = globalBucketMetadataSys.saveMetadata(ctx, objectAPI, meta); err != nil {
+	if !changed {
+		return nil
+	}
+	if err = globalBucketMetadataSys.saveMetadata(ctx, objectAPI, &meta); err != nil {
 		return err
 	}
 	unlock()
@@ -1716,62 +1709,35 @@ func (c *SiteReplicationSys) PeerBucketMetadataUpdateHandler(ctx context.Context
 
 // PeerBucketPolicyHandler - copies/deletes policy to local cluster.
 func (c *SiteReplicationSys) PeerBucketPolicyHandler(ctx context.Context, bucket string, policy *policy.BucketPolicy, updatedAt time.Time) error {
-	// skip overwrite if local update is newer than peer update.
-	if !updatedAt.IsZero() {
-		if _, updateTm, err := globalBucketMetadataSys.GetPolicyConfig(bucket); err == nil && updateTm.After(updatedAt) {
-			return nil
-		}
-	}
-
+	var data []byte
 	if policy != nil {
-		configData, err := json.Marshal(policy)
+		var err error
+		data, err = canonicalBucketPolicy(policy)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketPolicyConfig, configData)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		return nil
 	}
-
-	// Delete the bucket policy
-	_, err := globalBucketMetadataSys.Delete(ctx, bucket, bucketPolicyConfig)
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketPolicyConfig, data, false, false, &updatedAt)
 	if err != nil {
 		return wrapSRErr(err)
 	}
-
 	return nil
 }
 
 // PeerBucketTaggingHandler - copies/deletes tags to local cluster.
 func (c *SiteReplicationSys) PeerBucketTaggingHandler(ctx context.Context, bucket string, tags *string, updatedAt time.Time) error {
-	// skip overwrite if local update is newer than peer update.
-	if !updatedAt.IsZero() {
-		if _, updateTm, err := globalBucketMetadataSys.GetTaggingConfig(bucket); err == nil && updateTm.After(updatedAt) {
-			return nil
-		}
-	}
-
+	var data []byte
 	if tags != nil {
-		configData, err := base64.StdEncoding.DecodeString(*tags)
+		var err error
+		data, err = base64.StdEncoding.DecodeString(*tags)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketTaggingConfig, configData)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		return nil
 	}
-
-	// Delete the tags
-	_, err := globalBucketMetadataSys.Delete(ctx, bucket, bucketTaggingConfig)
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketTaggingConfig, data, false, false, &updatedAt)
 	if err != nil {
 		return wrapSRErr(err)
 	}
-
 	return nil
 }
 
@@ -1797,51 +1763,32 @@ func (c *SiteReplicationSys) peerBucketObjectLockConfigItem(ctx context.Context,
 
 // PeerBucketObjectLockConfigHandler - sets object lock on local bucket.
 func (c *SiteReplicationSys) PeerBucketObjectLockConfigHandler(ctx context.Context, bucket string, objectLockData *string, updatedAt time.Time) error {
+	var data []byte
 	if objectLockData != nil {
-		// skip overwrite if local update is newer than peer update.
-		if !updatedAt.IsZero() {
-			if _, updateTm, err := globalBucketMetadataSys.GetObjectLockConfig(bucket); err == nil && updateTm.After(updatedAt) {
-				return nil
-			}
-		}
-
-		configData, err := base64.StdEncoding.DecodeString(*objectLockData)
+		var err error
+		data, err = base64.StdEncoding.DecodeString(*objectLockData)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, objectLockConfig, configData)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		return nil
 	}
-
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, objectLockConfig, data, false, false, &updatedAt)
+	if err != nil {
+		return wrapSRErr(err)
+	}
 	return nil
 }
 
 // PeerBucketSSEConfigHandler - copies/deletes SSE config to local cluster.
 func (c *SiteReplicationSys) PeerBucketSSEConfigHandler(ctx context.Context, bucket string, sseConfig *string, updatedAt time.Time) error {
-	// skip overwrite if local update is newer than peer update.
-	if !updatedAt.IsZero() {
-		if _, updateTm, err := globalBucketMetadataSys.GetSSEConfig(bucket); err == nil && updateTm.After(updatedAt) {
-			return nil
-		}
-	}
-
+	var data []byte
 	if sseConfig != nil {
-		configData, err := base64.StdEncoding.DecodeString(*sseConfig)
+		var err error
+		data, err = base64.StdEncoding.DecodeString(*sseConfig)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketSSEConfig, configData)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		return nil
 	}
-
-	// Delete sse config
-	_, err := globalBucketMetadataSys.Delete(ctx, bucket, bucketSSEConfig)
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketSSEConfig, data, false, false, &updatedAt)
 	if err != nil {
 		return wrapSRErr(err)
 	}
@@ -2046,7 +1993,7 @@ func applyBucketCORSMetadata(ctx context.Context, objectAPI ObjectLayer, bucket
 
 	meta.CorsConfigXML = bytes.Clone(configData)
 	meta.CorsConfigUpdatedAt = updatedAt
-	if err = globalBucketMetadataSys.saveMetadata(ctx, objectAPI, meta); err != nil {
+	if err = globalBucketMetadataSys.saveMetadata(ctx, objectAPI, &meta); err != nil {
 		return time.Time{}, err
 	}
 	unlock()
@@ -2078,32 +2025,18 @@ func (c *SiteReplicationSys) PeerBucketCorsConfigHandler(ctx context.Context, bu
 
 // PeerBucketQuotaConfigHandler - copies/deletes policy to local cluster.
 func (c *SiteReplicationSys) PeerBucketQuotaConfigHandler(ctx context.Context, bucket string, quota *madmin.BucketQuota, updatedAt time.Time) error {
-	// skip overwrite if local update is newer than peer update.
-	if !updatedAt.IsZero() {
-		if _, updateTm, err := globalBucketMetadataSys.GetQuotaConfig(ctx, bucket); err == nil && updateTm.After(updatedAt) {
-			return nil
-		}
-	}
-
+	var data []byte
 	if quota != nil {
-		quotaData, err := json.Marshal(quota)
+		var err error
+		data, err = json.Marshal(quota)
 		if err != nil {
 			return wrapSRErr(err)
 		}
-
-		if _, err = globalBucketMetadataSys.Update(ctx, bucket, bucketQuotaConfigFile, quotaData); err != nil {
-			return wrapSRErr(err)
-		}
-
-		return nil
 	}
-
-	// Delete the bucket policy
-	_, err := globalBucketMetadataSys.Delete(ctx, bucket, bucketQuotaConfigFile)
+	_, err := globalBucketMetadataSys.updateAndParseMetadata(ctx, bucket, bucketQuotaConfigFile, data, false, false, &updatedAt)
 	if err != nil {
 		return wrapSRErr(err)
 	}
-
 	return nil
 }