Merge branch 'audit/issue-105-bucketmeta-races' into codex/bucket-metadata-merge-20260908

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

cmd/bucket-metadata-race_test.go

@@ -0,0 +1,408 @@
+// Copyright (c) 2015-2026 MinIO, Inc.
+// Copyright (c) 2026 PGSTY
+//
+// 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.
+
+package cmd
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"errors"
+	"io"
+	"net/http"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/minio/minio/internal/auth"
+)
+
+// ---------------------------------------------------------------------------
+// Target 1 (issue #105): a higher-level lifecycle XML merge racing another
+// bucket-metadata transition outside BucketMetadataSys.Delete.
+//
+// Before the fix, PeerBucketLCConfigHandler / healBucketILMExpiry read the
+// current lifecycle document without metadata.lock, merged the replicated expiry
+// rules with the local transition rules, and then persisted the merged blob with
+// BucketMetadataSys.Update. Update re-read the record under metadata.lock but
+// overwrote LifecycleConfigXML wholesale with the pre-computed blob, so any
+// lifecycle transition change committed between the merge read and the merge
+// write was silently lost on disk. BucketMetadataSys.UpdateExpiryLCConfig now
+// performs the read, merge, and save under a single metadata.lock. This test
+// drives PeerBucketLCConfigHandler and asserts the concurrent change survives.
+// ---------------------------------------------------------------------------
+
+type lcMergeWriterKey struct{}
+
+// lcMergeBarrier pauses the merge writer (context value "M") exactly when it
+// tries to take metadata.lock for its persisting Update. By that point the
+// merge has already read the stale lifecycle document, so the test can commit a
+// concurrent transition change before releasing the merge write.
+type lcMergeBarrier struct {
+	ObjectLayer
+	bucket   string
+	mAtLock  chan struct{}
+	mProceed chan struct{}
+	mOnce    sync.Once
+}
+
+func (o *lcMergeBarrier) metadataLock() string {
+	return pathJoin(bucketMetaPrefix, o.bucket, "metadata.lock")
+}
+
+func (o *lcMergeBarrier) NewNSLock(bucket string, objects ...string) RWLocker {
+	lock := o.ObjectLayer.NewNSLock(bucket, objects...)
+	if bucket != minioMetaBucket || len(objects) != 1 || objects[0] != o.metadataLock() {
+		return lock
+	}
+	return metadataObservedRWLocker{RWLocker: lock, onLock: func(ctx context.Context) {
+		if ctx.Value(lcMergeWriterKey{}) != "M" {
+			return
+		}
+		o.mOnce.Do(func() { close(o.mAtLock) })
+		select {
+		case <-o.mProceed:
+		case <-ctx.Done():
+		}
+	}}
+}
+
+func TestLifecycleExpiryMergeRaceLosesConcurrentTransition(t *testing.T) {
+	defer DetectTestLeak(t)()
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{
+		t:          t,
+		objAPITest: testLifecycleExpiryMergeRaceLosesConcurrentTransition,
+	})
+}
+
+func testLifecycleExpiryMergeRaceLosesConcurrentTransition(obj ObjectLayer, instanceType, bucket string,
+	_ http.Handler, _ auth.Credentials, t *testing.T,
+) {
+	// Revision N: a single transition-only rule.
+	baseXML := []byte(`<LifecycleConfiguration><Rule><ID>keep</ID><Filter><Prefix>data/</Prefix></Filter><Status>Enabled</Status><Transition><Days>30</Days><StorageClass>WARM</StorageClass></Transition></Rule></LifecycleConfiguration>`)
+	if _, err := globalBucketMetadataSys.Update(t.Context(), bucket, bucketLifecycleConfig, baseXML); err != nil {
+		t.Fatalf("%s: seed lifecycle: %v", instanceType, err)
+	}
+
+	// A replicated expiry-only rule arriving from a peer site.
+	expXML := `<LifecycleConfiguration><Rule><ID>expire</ID><Filter><Prefix>tmp/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>7</Days></Expiration></Rule></LifecycleConfiguration>`
+	expLCConfig := base64.StdEncoding.EncodeToString([]byte(expXML))
+
+	previousObjectAPI := newObjectLayerFn()
+	barrier := &lcMergeBarrier{
+		ObjectLayer: obj,
+		bucket:      bucket,
+		mAtLock:     make(chan struct{}),
+		mProceed:    make(chan struct{}),
+	}
+	setObjectLayer(barrier)
+	defer setObjectLayer(previousObjectAPI)
+
+	ctx, cancel := context.WithTimeout(t.Context(), 30*time.Second)
+	defer cancel()
+	mCtx := context.WithValue(ctx, lcMergeWriterKey{}, "M")
+
+	mDone := make(chan error, 1)
+	go func() {
+		mDone <- globalSiteReplicationSys.PeerBucketLCConfigHandler(mCtx, bucket, &expLCConfig, UTCNow())
+	}()
+
+	// Wait until the merge writer has read revision N and is about to persist.
+	select {
+	case <-barrier.mAtLock:
+	case err := <-mDone:
+		t.Fatalf("%s: merge writer finished before persisting: %v", instanceType, err)
+	case <-ctx.Done():
+		t.Fatalf("%s: merge writer never reached metadata.lock: %v", instanceType, ctx.Err())
+	}
+
+	// Concurrent local lifecycle transition change commits revision N+1.
+	concurrentXML := []byte(`<LifecycleConfiguration><Rule><ID>keep</ID><Filter><Prefix>data/</Prefix></Filter><Status>Enabled</Status><Transition><Days>10</Days><StorageClass>COLD</StorageClass></Transition></Rule></LifecycleConfiguration>`)
+	if _, err := globalBucketMetadataSys.Update(ctx, bucket, bucketLifecycleConfig, concurrentXML); err != nil {
+		t.Fatalf("%s: concurrent transition update: %v", instanceType, err)
+	}
+
+	// Release the merge write so it lands after the concurrent commit.
+	close(barrier.mProceed)
+	if err := <-mDone; err != nil {
+		t.Fatalf("%s: merge writer failed: %v", instanceType, err)
+	}
+
+	// The persisted lifecycle must contain both the replicated expiry rule and
+	// the concurrent transition change.
+	cfg, _, err := globalBucketMetadataSys.GetLifecycleConfig(bucket)
+	if err != nil {
+		t.Fatalf("%s: read merged lifecycle: %v", instanceType, err)
+	}
+	var keep, expire bool
+	for i := range cfg.Rules {
+		switch cfg.Rules[i].ID {
+		case "keep":
+			keep = true
+			if cfg.Rules[i].Transition.Days != 10 || cfg.Rules[i].Transition.StorageClass != "COLD" {
+				t.Fatalf("%s: lifecycle merge overwrote the concurrent transition change: got Days=%d StorageClass=%q, want Days=10 StorageClass=COLD",
+					instanceType, cfg.Rules[i].Transition.Days, cfg.Rules[i].Transition.StorageClass)
+			}
+		case "expire":
+			expire = true
+		}
+	}
+	if !expire {
+		t.Fatalf("%s: merged lifecycle dropped the replicated expiry rule: %+v", instanceType, cfg.Rules)
+	}
+	if !keep {
+		t.Fatalf("%s: merged lifecycle dropped the transition rule entirely: %+v", instanceType, cfg.Rules)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Target 2 (issue #105): DeleteBucket racing an already in-flight metadata
+// writer and resurrecting a ghost .metadata.bin record.
+//
+// erasureServerPools.DeleteBucket takes only <bucket>.lck and purges the whole
+// metadata prefix with deleteAll. Config writers (updateAndParse) take only
+// metadata.lock. The two locks do not exclude each other, so a writer that is
+// past its read and holding metadata.lock can persist .metadata.bin AFTER the
+// delete has purged the prefix, resurrecting a record for a deleted bucket.
+// ---------------------------------------------------------------------------
+
+func TestDeleteBucketResurrectsGhostMetadata(t *testing.T) {
+	defer DetectTestLeak(t)()
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{
+		t:          t,
+		objAPITest: testDeleteBucketResurrectsGhostMetadata,
+	})
+}
+
+func testDeleteBucketResurrectsGhostMetadata(obj ObjectLayer, instanceType, bucket string,
+	_ http.Handler, _ auth.Credentials, t *testing.T,
+) {
+	previousObjectAPI := newObjectLayerFn()
+	barrier := &metadataRMWBarrierObjectLayer{
+		ObjectLayer:  obj,
+		bucket:       bucket,
+		aReady:       make(chan struct{}),
+		aRelease:     make(chan struct{}),
+		bLockAttempt: make(chan struct{}),
+	}
+	setObjectLayer(barrier)
+	defer setObjectLayer(previousObjectAPI)
+
+	ctx, cancel := context.WithTimeout(t.Context(), 30*time.Second)
+	defer cancel()
+	aCtx := context.WithValue(ctx, metadataRMWWriterKey{}, "A")
+
+	policyJSON := []byte(`{"Version":"2012-10-17","Statement":[{"Effect":"Allow","Principal":"*","Action":"s3:GetObject","Resource":"arn:aws:s3:::` + bucket + `/*"}]}`)
+	aDone := make(chan error, 1)
+	// Writer A holds metadata.lock and pauses at the .metadata.bin PutObject.
+	go func() {
+		_, err := globalBucketMetadataSys.Update(aCtx, bucket, bucketPolicyConfig, policyJSON)
+		aDone <- err
+	}()
+
+	select {
+	case <-barrier.aReady:
+	case err := <-aDone:
+		t.Fatalf("%s: writer A finished before persisting: %v", instanceType, err)
+	case <-ctx.Done():
+		t.Fatalf("%s: writer A never reached metadata save: %v", instanceType, ctx.Err())
+	}
+
+	// Delete the bucket while writer A is paused mid-save.
+	delDone := make(chan error, 1)
+	go func() {
+		delDone <- obj.DeleteBucket(ctx, bucket, DeleteBucketOptions{Force: true})
+	}()
+
+	select {
+	case err := <-delDone:
+		// Unfixed path: DeleteBucket does not serialize on metadata.lock, so it
+		// purges the prefix immediately. Release A so its save recreates the file.
+		if err != nil {
+			t.Fatalf("%s: delete bucket: %v", instanceType, err)
+		}
+		close(barrier.aRelease)
+		if err := <-aDone; err != nil {
+			t.Fatalf("%s: writer A failed: %v", instanceType, err)
+		}
+	case <-time.After(3 * time.Second):
+		// Fixed path: DeleteBucket is blocked waiting for metadata.lock held by
+		// A. Release A so it finishes, then the purge runs after the save.
+		close(barrier.aRelease)
+		if err := <-aDone; err != nil {
+			t.Fatalf("%s: writer A failed: %v", instanceType, err)
+		}
+		if err := <-delDone; err != nil {
+			t.Fatalf("%s: delete bucket: %v", instanceType, err)
+		}
+	}
+
+	// After DeleteBucket, no .metadata.bin record may remain on disk.
+	if meta, err := readBucketMetadata(ctx, obj, bucket); err == nil {
+		t.Fatalf("%s: ghost .metadata.bin resurrected after DeleteBucket: name=%q created=%s policyLen=%d",
+			instanceType, meta.Name, meta.Created, len(meta.PolicyConfigJSON))
+	} else if !errors.Is(err, errConfigNotFound) && !isErrBucketNotFound(err) && !errors.Is(err, errVolumeNotFound) {
+		t.Fatalf("%s: unexpected error reading deleted bucket metadata: %v", instanceType, err)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Target 3 (issue #105): overlapping peer reloads publishing an older cache
+// record after a newer save, leaving the resident cache one revision behind
+// until refresh.
+//
+// LoadBucketMetadataHandler does loadBucketMetadata (read) followed by a publish
+// into the resident cache. Before the fix that publish was an unconditional
+// BucketMetadataSys.Set, so a reload that read an older on-disk revision could
+// overwrite a newer resident record when it published late (unlike
+// refreshBucketsMetadataLoop, which guards on lastUpdate()). The publish is now
+// BucketMetadataSys.setReloaded, which refuses to regress a newer resident copy.
+//
+// The peer handler hardcodes context.Background(), so its reload core is mirrored
+// here to inject deterministic ordering. This is a resident-cache freshness
+// defect only: the persisted record always stays correct.
+// ---------------------------------------------------------------------------
+
+type reloadWriterKey struct{}
+
+// reloadStaleBarrier captures the old on-disk metadata for the reload tagged
+// "R1" and holds R1's read open until released, so a newer revision can be
+// written and published before R1 finishes publishing the stale copy.
+type reloadStaleBarrier struct {
+	ObjectLayer
+	bucket    string
+	r1Reading chan struct{}
+	r1Release chan struct{}
+	once      sync.Once
+}
+
+func (o *reloadStaleBarrier) metadataObject() string {
+	return pathJoin(bucketMetaPrefix, o.bucket, bucketMetadataFile)
+}
+
+func (o *reloadStaleBarrier) GetObjectNInfo(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, h http.Header, opts ObjectOptions) (*GetObjectReader, error) {
+	if bucket == minioMetaBucket && object == o.metadataObject() && ctx.Value(reloadWriterKey{}) == "R1" {
+		gr, err := o.ObjectLayer.GetObjectNInfo(ctx, bucket, object, rs, h, opts)
+		if err != nil {
+			return nil, err
+		}
+		data, rerr := io.ReadAll(gr)
+		oi := gr.ObjInfo
+		gr.Close()
+		if rerr != nil {
+			return nil, rerr
+		}
+		o.once.Do(func() { close(o.r1Reading) })
+		select {
+		case <-o.r1Release:
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
+		return NewGetObjectReaderFromReader(bytes.NewReader(data), oi, opts)
+	}
+	return o.ObjectLayer.GetObjectNInfo(ctx, bucket, object, rs, h, opts)
+}
+
+func TestOverlappingReloadPublishesStaleResidentCache(t *testing.T) {
+	defer DetectTestLeak(t)()
+	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{
+		t:          t,
+		objAPITest: testOverlappingReloadPublishesStaleResidentCache,
+	})
+}
+
+func residentTagValue(t *testing.T, instanceType, bucket string) string {
+	t.Helper()
+	cfg, _, err := globalBucketMetadataSys.GetTaggingConfig(bucket)
+	if err != nil {
+		t.Fatalf("%s: read resident tagging: %v", instanceType, err)
+	}
+	return cfg.ToMap()["rev"]
+}
+
+func testOverlappingReloadPublishesStaleResidentCache(obj ObjectLayer, instanceType, bucket string,
+	_ http.Handler, _ auth.Credentials, t *testing.T,
+) {
+	// Revision 0 on disk and in the resident cache.
+	tag0 := []byte(`<Tagging><TagSet><Tag><Key>rev</Key><Value>0</Value></Tag></TagSet></Tagging>`)
+	if _, err := globalBucketMetadataSys.Update(t.Context(), bucket, bucketTaggingConfig, tag0); err != nil {
+		t.Fatalf("%s: seed rev0: %v", instanceType, err)
+	}
+
+	previousObjectAPI := newObjectLayerFn()
+	barrier := &reloadStaleBarrier{
+		ObjectLayer: obj,
+		bucket:      bucket,
+		r1Reading:   make(chan struct{}),
+		r1Release:   make(chan struct{}),
+	}
+	setObjectLayer(barrier)
+	defer setObjectLayer(previousObjectAPI)
+
+	ctx, cancel := context.WithTimeout(t.Context(), 30*time.Second)
+	defer cancel()
+	r1Ctx := context.WithValue(ctx, reloadWriterKey{}, "R1")
+
+	// reload mirrors the core of LoadBucketMetadataHandler (which hardcodes
+	// context.Background() and cannot take an injected context). The publish
+	// uses setReloaded, exactly as the fixed handler does.
+	reload := func(rctx context.Context) error {
+		meta, err := loadBucketMetadata(rctx, newObjectLayerFn(), bucket)
+		if err != nil {
+			return err
+		}
+		globalBucketMetadataSys.setReloaded(bucket, meta)
+		return nil
+	}
+
+	// R1: an overlapping peer reload that reads rev0 and then stalls before it
+	// publishes.
+	r1Done := make(chan error, 1)
+	go func() { r1Done <- reload(r1Ctx) }()
+
+	select {
+	case <-barrier.r1Reading:
+	case err := <-r1Done:
+		t.Fatalf("%s: R1 finished before publishing: %v", instanceType, err)
+	case <-ctx.Done():
+		t.Fatalf("%s: R1 never read metadata: %v", instanceType, ctx.Err())
+	}
+
+	// A newer save commits revision 1 to disk and the resident cache.
+	tag1 := []byte(`<Tagging><TagSet><Tag><Key>rev</Key><Value>1</Value></Tag></TagSet></Tagging>`)
+	if _, err := globalBucketMetadataSys.Update(ctx, bucket, bucketTaggingConfig, tag1); err != nil {
+		t.Fatalf("%s: commit rev1: %v", instanceType, err)
+	}
+	// R2: a second overlapping peer reload that reads rev1 and publishes it.
+	if err := reload(ctx); err != nil {
+		t.Fatalf("%s: R2 reload: %v", instanceType, err)
+	}
+	if got := residentTagValue(t, instanceType, bucket); got != "1" {
+		t.Fatalf("%s: precondition failed, resident cache should be rev1 before R1 publishes, got %q", instanceType, got)
+	}
+
+	// Release R1 so its stale publish lands after the newer save.
+	close(barrier.r1Release)
+	if err := <-r1Done; err != nil {
+		t.Fatalf("%s: R1 reload: %v", instanceType, err)
+	}
+
+	// The persisted record must stay at rev1 (persistent correctness).
+	if dcfg, perr := globalBucketMetadataSys.GetConfigFromDisk(ctx, bucket); perr != nil {
+		t.Fatalf("%s: reload disk metadata: %v", instanceType, perr)
+	} else if got := dcfg.taggingConfig.ToMap()["rev"]; got != "1" {
+		t.Fatalf("%s: persisted record regressed to rev %q, want rev1", instanceType, got)
+	}
+
+	// The resident cache must not be left behind at rev0.
+	if got := residentTagValue(t, instanceType, bucket); got != "1" {
+		t.Fatalf("%s: overlapping reload left resident cache at rev %q, want rev1", instanceType, got)
+	}
+}

cmd/bucket-metadata-sys.go

@@ -125,6 +125,28 @@ func (sys *BucketMetadataSys) Set(bucket string, meta BucketMetadata) {
 	}
 }
 
+// setReloaded publishes a record freshly loaded from disk into the resident
+// cache without letting an older on-disk revision overwrite a newer resident
+// one. Overlapping peer reloads (LoadBucketMetadataHandler) and cache-miss
+// loads can finish out of order, so an unconditional Set can leave the resident
+// cache a revision behind until the next refresh (issue #105). The authoritative
+// read-modify-write save path uses Set directly and always wins because it
+// stamps a fresh updatedAt. Only a shallow copy is stored, exactly like Set.
+func (sys *BucketMetadataSys) setReloaded(bucket string, meta BucketMetadata) {
+	if isMinioMetaBucketName(bucket) {
+		return
+	}
+	sys.Lock()
+	defer sys.Unlock()
+	if cur, ok := sys.metadataMap[bucket]; ok && !cur.lastUpdate().Before(meta.lastUpdate()) {
+		// A resident revision that is at least as new is already published; do
+		// not regress it to the older reload.
+		return
+	}
+	sys.metadataMap[bucket] = meta
+	sys.clearLoadFailure(bucket)
+}
+
 func (sys *BucketMetadataSys) updateAndParse(ctx context.Context, bucket string, configFile string, configData []byte, parse, lifecycleDelete bool) (updatedAt time.Time, err error) {
 	objAPI := newObjectLayerFn()
 	if objAPI == nil {
@@ -292,6 +314,57 @@ func (sys *BucketMetadataSys) Update(ctx context.Context, bucket string, configF
 	return sys.updateAndParse(ctx, bucket, configFile, configData, true, false)
 }
 
+// UpdateExpiryLCConfig merges a replicated ILM expiry configuration with the
+// bucket's current lifecycle document and persists the merged result while
+// holding metadata.lock across the read, merge, and save. The site-replication
+// expiry heal and peer-apply paths must use this instead of computing the merge
+// from an unlocked GetConfigFromDisk read and then writing it with Update: that
+// two-step sequence drops any lifecycle transition change committed in between
+// (issue #105). Lock order stays <bucket>.lck -> metadata.lock -> .metadata.bin;
+// the merge and save run under metadata.lock and the peer fan-out runs after it
+// is released.
+func (sys *BucketMetadataSys) UpdateExpiryLCConfig(ctx context.Context, bucket string, expLCConfig *string, updatedAt time.Time) error {
+	objAPI := newObjectLayerFn()
+	if objAPI == nil {
+		return errServerNotInitialized
+	}
+
+	if isMinioMetaBucketName(bucket) {
+		return errInvalidArgument
+	}
+
+	notifyCtx := ctx
+	ctx, unlock, err := lockBucketMetadata(ctx, objAPI, bucket)
+	if err != nil {
+		return err
+	}
+
+	err = func() error {
+		defer unlock()
+		meta, err := loadBucketMetadataParse(ctx, objAPI, bucket, true)
+		if err != nil {
+			if !globalIsErasure && !globalIsDistErasure && errors.Is(err, errVolumeNotFound) {
+				// Only single drive mode needs this fallback.
+				meta = newBucketMetadata(bucket)
+			} else {
+				return err
+			}
+		}
+		configData, err := mergeExpiryWithLCConfig(bucket, meta, expLCConfig, updatedAt)
+		if err != nil {
+			return err
+		}
+		meta.LifecycleConfigXML = configData
+		meta.LifecycleConfigUpdatedAt = UTCNow()
+		return sys.saveMetadata(ctx, objAPI, meta)
+	}()
+	if err != nil {
+		return err
+	}
+	globalNotificationSys.LoadBucketMetadata(bgContext(notifyCtx), bucket) // Do not use caller context here
+	return nil
+}
+
 // Get metadata for a bucket.
 // If no metadata exists errConfigNotFound is returned and a new metadata is returned.
 // Only a shallow copy is returned, so referenced data should not be modified,
@@ -602,7 +675,13 @@ func (sys *BucketMetadataSys) GetConfig(ctx context.Context, bucket string) (met
 		return meta, false, err
 	}
 	sys.Lock()
-	sys.metadataMap[bucket] = meta
+	if cur, ok := sys.metadataMap[bucket]; ok && !cur.lastUpdate().Before(meta.lastUpdate()) {
+		// A concurrent publish installed a resident revision at least as new as
+		// this cache-miss load; return it instead of regressing (issue #105).
+		meta = cur
+	} else {
+		sys.metadataMap[bucket] = meta
+	}
 	sys.clearLoadFailure(bucket)
 	sys.Unlock()
 

cmd/erasure-server-pool.go

@@ -2204,8 +2204,18 @@ func (z *erasureServerPools) DeleteBucket(ctx context.Context, bucket string, op
 	}
 
 	if err == nil {
-		// Purge the entire bucket metadata entirely.
-		z.deleteAll(context.Background(), minioMetaBucket, pathJoin(bucketMetaPrefix, bucket))
+		// Purge the entire bucket metadata entirely. Hold metadata.lock across
+		// the purge so a bucket metadata writer that is mid-save cannot
+		// resurrect a ghost .metadata.bin after the prefix has been removed
+		// (issue #105). Lock order stays <bucket>.lck -> metadata.lock; a lock
+		// acquisition failure falls back to a best-effort unlocked purge so a
+		// delete is never blocked from completing.
+		if lctx, unlock, lerr := lockBucketMetadata(context.Background(), z, bucket); lerr == nil {
+			z.deleteAll(lctx, minioMetaBucket, pathJoin(bucketMetaPrefix, bucket))
+			unlock()
+		} else {
+			z.deleteAll(context.Background(), minioMetaBucket, pathJoin(bucketMetaPrefix, bucket))
+		}
 	}
 
 	return toObjectErr(err, bucket)

cmd/peer-rest-server.go

@@ -544,7 +544,9 @@ func (s *peerRESTServer) LoadBucketMetadataHandler(mss *grid.MSS) (np grid.NoPay
 		return np, grid.NewRemoteErr(err)
 	}
 
-	globalBucketMetadataSys.Set(bucketName, meta)
+	// Publish monotonically: an overlapping reload that read an older revision
+	// must not overwrite a newer resident record (issue #105).
+	globalBucketMetadataSys.setReloaded(bucketName, meta)
 
 	if meta.notificationConfig != nil {
 		globalEventNotifier.AddRulesMap(bucketName, meta.notificationConfig.ToRulesMap())

cmd/site-replication.go

@@ -45,6 +45,7 @@ import (
 	"github.com/minio/minio/internal/auth"
 	"github.com/minio/minio/internal/bucket/cors"
 	"github.com/minio/minio/internal/bucket/lifecycle"
+	objectlock "github.com/minio/minio/internal/bucket/object/lock"
 	sreplication "github.com/minio/minio/internal/bucket/replication"
 	"github.com/minio/minio/internal/bucket/versioning"
 	"github.com/minio/minio/internal/logger"
@@ -2115,12 +2116,7 @@ func (c *SiteReplicationSys) PeerBucketLCConfigHandler(ctx context.Context, buck
 	}
 
 	if expLCConfig != nil {
-		configData, err := mergeWithCurrentLCConfig(ctx, bucket, expLCConfig, updatedAt)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-		_, err = globalBucketMetadataSys.Update(ctx, bucket, bucketLifecycleConfig, configData)
-		if err != nil {
+		if err := globalBucketMetadataSys.UpdateExpiryLCConfig(ctx, bucket, expLCConfig, updatedAt); err != nil {
 			return wrapSRErr(err)
 		}
 		return nil
@@ -4922,13 +4918,12 @@ func (c *SiteReplicationSys) healBucketILMExpiry(ctx context.Context, objAPI Obj
 			continue
 		}
 
-		finalConfigData, err := mergeWithCurrentLCConfig(ctx, bucket, latestExpLCConfig, lastUpdate)
-		if err != nil {
-			return wrapSRErr(err)
-		}
-
 		if dID == globalDeploymentID() {
-			if _, err := globalBucketMetadataSys.Update(ctx, bucket, bucketLifecycleConfig, finalConfigData); err != nil {
+			// Merge and persist atomically under metadata.lock so a concurrent
+			// lifecycle transition change is not lost (issue #105). The merged
+			// blob is recomputed from the locked current document here rather
+			// than from an earlier unlocked read.
+			if err := globalBucketMetadataSys.UpdateExpiryLCConfig(ctx, bucket, latestExpLCConfig, lastUpdate); err != nil {
 				replLogIf(ctx, fmt.Errorf("Unable to heal bucket ILM expiry data from peer site %s : %w", latestPeerName, err))
 			}
 			continue
@@ -6594,13 +6589,12 @@ func (c *SiteReplicationSys) getSiteMetrics(ctx context.Context) (madmin.SRMetri
 	return sm, nil
 }
 
-// mergeWithCurrentLCConfig - merges the given ilm expiry configuration with existing for the current site and returns
-func mergeWithCurrentLCConfig(ctx context.Context, bucket string, expLCCfg *string, updatedAt time.Time) ([]byte, error) {
-	// Get bucket config from current site
-	meta, e := globalBucketMetadataSys.GetConfigFromDisk(ctx, bucket)
-	if e != nil && !errors.Is(e, errConfigNotFound) {
-		return []byte{}, e
-	}
+// mergeExpiryWithLCConfig merges the given ILM expiry configuration with the
+// supplied current bucket lifecycle document and returns the merged XML. The
+// current document must be read by the caller while holding metadata.lock (see
+// BucketMetadataSys.UpdateExpiryLCConfig) so a concurrent lifecycle transition
+// change cannot be lost between the read and the merged save (issue #105).
+func mergeExpiryWithLCConfig(bucket string, meta BucketMetadata, expLCCfg *string, updatedAt time.Time) ([]byte, error) {
 	rMap := make(map[string]lifecycle.Rule)
 	var xmlName xml.Name
 	if len(meta.LifecycleConfigXML) > 0 {
@@ -6611,7 +6605,7 @@ func mergeWithCurrentLCConfig(ctx context.Context, bucket string, expLCCfg *stri
 		for _, rl := range lcCfg.Rules {
 			rMap[rl.ID] = rl
 		}
-		xmlName = meta.lifecycleConfig.XMLName
+		xmlName = lcCfg.XMLName
 	}
 
 	// get latest expiry rules
@@ -6683,11 +6677,13 @@ func mergeWithCurrentLCConfig(ctx context.Context, bucket string, expLCCfg *stri
 		ExpiryUpdatedAt: &updatedAt,
 	}
 
-	rcfg, err := globalBucketObjectLockSys.Get(bucket)
-	if err != nil {
-		return nil, err
+	// Validate against the object-lock retention from the locked metadata
+	// snapshot rather than re-reading it, which would risk a re-entrant
+	// metadata load while metadata.lock is held (issue #105).
+	var rcfg objectlock.Retention
+	if meta.objectLockConfig != nil {
+		rcfg = meta.objectLockConfig.ToRetention()
 	}
-
 	if err := finalLcCfg.Validate(rcfg); err != nil {
 		return []byte{}, err
 	}