Revamp bucket metadata healing (#7208)

Bucket metadata healing in the current code was executed multiple
times each time for a given set. Bucket metadata just like
objects are hashed in accordance with its name on any given set,
to allow hashing to play a role we should let the top level
code decide where to navigate.

Current code also had 3 bucket metadata files hardcoded, whereas
we should make it generic by listing and navigating the .minio.sys
to heal such objects.

We also had another bug where due to isObjectDangling changes
without pre-existing bucket metadata files, we were erroneously
reporting it as grey/corrupted objects.

This PR fixes all of the above items.

cmd/admin-heal-ops.go

@@ -546,8 +546,11 @@ func (h *healSequence) traverseAndHeal() {
 	// Start with format healing
 	checkErr(h.healDiskFormat)
 
-	// Start healing the config.
-	checkErr(h.healConfig)
+	// Start healing the config prefix.
+	checkErr(h.healMinioSysMeta(minioConfigPrefix))
+
+	// Start healing the bucket config prefix.
+	checkErr(h.healMinioSysMeta(bucketConfigPrefix))
 
 	// Heal buckets and objects
 	checkErr(h.healBuckets)
@@ -559,17 +562,19 @@ func (h *healSequence) traverseAndHeal() {
 	close(h.traverseAndHealDoneCh)
 }
 
-// healConfig - heals config.json, retrun value indicates if a failure occurred.
-func (h *healSequence) healConfig() error {
+// healMinioSysMeta - heals all files under a given meta prefix, returns a function
+// which in-turn heals the respective meta directory path and any files in int.
+func (h *healSequence) healMinioSysMeta(metaPrefix string) func() error {
+	return func() error {
 		// Get current object layer instance.
 		objectAPI := newObjectLayerFn()
 		if objectAPI == nil {
 			return errServerNotInitialized
 		}
 
-	// NOTE: Healing on configs is run regardless
+		// NOTE: Healing on meta is run regardless
 		// of any bucket being selected, this is to ensure that
-	// configs are always uptodate and correct.
+		// meta are always upto date and correct.
 		marker := ""
 		isTruncated := true
 		for isTruncated {
@@ -585,7 +590,7 @@ func (h *healSequence) healConfig() error {
 			}
 
 			// Lists all objects under `config` prefix.
-		objectInfos, err := objectAPI.ListObjectsHeal(h.ctx, minioMetaBucket, minioConfigPrefix,
+			objectInfos, err := objectAPI.ListObjectsHeal(h.ctx, minioMetaBucket, metaPrefix,
 				marker, "", 1000)
 			if err != nil {
 				return errFnHealFromAPIErr(h.ctx, err)
@@ -614,9 +619,9 @@ func (h *healSequence) healConfig() error {
 			isTruncated = objectInfos.IsTruncated
 			marker = objectInfos.NextMarker
 		}
-
 		return nil
 	}
+}
 
 // healDiskFormat - heals format.json, return value indicates if a
 // failure error occurred.
@@ -692,18 +697,16 @@ func (h *healSequence) healBucket(bucket string) error {
 		return errServerNotInitialized
 	}
 
-	results, err := objectAPI.HealBucket(h.ctx, bucket, h.settings.DryRun, h.settings.Remove)
-	// push any available results before checking for error
-	for _, result := range results {
-		if perr := h.pushHealResultItem(result); perr != nil {
-			return perr
-		}
-	}
+	result, err := objectAPI.HealBucket(h.ctx, bucket, h.settings.DryRun, h.settings.Remove)
 	// handle heal-bucket error
 	if err != nil {
 		return err
 	}
 
+	if err = h.pushHealResultItem(result); err != nil {
+		return err
+	}
+
 	if !h.settings.Recursive {
 		if h.objPrefix != "" {
 			// Check if an object named as the objPrefix exists,

cmd/dummy-object-layer_test.go

@@ -119,7 +119,7 @@ func (api *DummyObjectLayer) HealFormat(ctx context.Context, dryRun bool) (item
 	return
 }
 
-func (api *DummyObjectLayer) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (items []madmin.HealResultItem, err error) {
+func (api *DummyObjectLayer) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (items madmin.HealResultItem, err error) {
 	return
 }
 

cmd/fs-v1.go

@@ -1252,10 +1252,10 @@ func (fs *FSObjects) HealObject(ctx context.Context, bucket, object string, dryR
 }
 
 // HealBucket - no-op for fs, Valid only for XL.
-func (fs *FSObjects) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) ([]madmin.HealResultItem,
+func (fs *FSObjects) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (madmin.HealResultItem,
 	error) {
 	logger.LogIf(ctx, NotImplemented{})
-	return nil, NotImplemented{}
+	return madmin.HealResultItem{}, NotImplemented{}
 }
 
 // ListObjectsHeal - list all objects to be healed. Valid only for XL

cmd/gateway-unsupported.go

@@ -92,8 +92,8 @@ func (a GatewayUnsupported) HealFormat(ctx context.Context, dryRun bool) (madmin
 }
 
 // HealBucket - Not implemented stub
-func (a GatewayUnsupported) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) ([]madmin.HealResultItem, error) {
-	return nil, NotImplemented{}
+func (a GatewayUnsupported) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (madmin.HealResultItem, error) {
+	return madmin.HealResultItem{}, NotImplemented{}
 }
 
 // ListBucketsHeal - Not implemented stub

cmd/object-api-interface.go

@@ -83,7 +83,7 @@ type ObjectLayer interface {
 	// Healing operations.
 	ReloadFormat(ctx context.Context, dryRun bool) error
 	HealFormat(ctx context.Context, dryRun bool) (madmin.HealResultItem, error)
-	HealBucket(ctx context.Context, bucket string, dryRun, remove bool) ([]madmin.HealResultItem, error)
+	HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (madmin.HealResultItem, error)
 	HealObject(ctx context.Context, bucket, object string, dryRun, remove bool) (madmin.HealResultItem, error)
 	ListBucketsHeal(ctx context.Context) (buckets []BucketInfo, err error)
 	ListObjectsHeal(ctx context.Context, bucket, prefix, marker, delimiter string, maxKeys int) (ListObjectsInfo, error)

cmd/xl-sets.go

@@ -1232,15 +1232,15 @@ func (s *xlSets) HealFormat(ctx context.Context, dryRun bool) (res madmin.HealRe
 }
 
 // HealBucket - heals inconsistent buckets and bucket metadata on all sets.
-func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (results []madmin.HealResultItem, err error) {
+func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (result madmin.HealResultItem, err error) {
 	bucketLock := globalNSMutex.NewNSLock(bucket, "")
 	if err := bucketLock.GetLock(globalHealingTimeout); err != nil {
-		return nil, err
+		return result, err
 	}
 	defer bucketLock.Unlock()
 
 	// Initialize heal result info
-	res := madmin.HealResultItem{
+	result = madmin.HealResultItem{
 		Type:      madmin.HealItemBucket,
 		Bucket:    bucket,
 		DiskCount: s.setCount * s.drivesPerSet,
@@ -1248,25 +1248,22 @@ func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove b
 	}
 
 	for _, s := range s.sets {
-		var setResults []madmin.HealResultItem
-		setResults, _ = s.HealBucket(ctx, bucket, dryRun, remove)
-		for _, setResult := range setResults {
-			if setResult.Type == madmin.HealItemBucket {
-				for _, v := range setResult.Before.Drives {
-					res.Before.Drives = append(res.Before.Drives, v)
+		var healResult madmin.HealResultItem
+		healResult, err = s.HealBucket(ctx, bucket, dryRun, remove)
+		if err != nil {
+			return result, err
 		}
-				for _, v := range setResult.After.Drives {
-					res.After.Drives = append(res.After.Drives, v)
+		for _, v := range healResult.Before.Drives {
+			result.Before.Drives = append(result.Before.Drives, v)
 		}
-				continue
-			}
-			results = append(results, setResult)
+		for _, v := range healResult.After.Drives {
+			result.After.Drives = append(result.After.Drives, v)
 		}
 	}
 
 	for _, endpoint := range s.endpoints {
 		var foundBefore bool
-		for _, v := range res.Before.Drives {
+		for _, v := range result.Before.Drives {
 			if endpoint.IsLocal {
 				if v.Endpoint == endpoint.Path {
 					foundBefore = true
@@ -1278,14 +1275,14 @@ func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove b
 			}
 		}
 		if !foundBefore {
-			res.Before.Drives = append(res.Before.Drives, madmin.HealDriveInfo{
+			result.Before.Drives = append(result.Before.Drives, madmin.HealDriveInfo{
 				UUID:     "",
 				Endpoint: endpoint.String(),
 				State:    madmin.DriveStateOffline,
 			})
 		}
 		var foundAfter bool
-		for _, v := range res.After.Drives {
+		for _, v := range result.After.Drives {
 			if endpoint.IsLocal {
 				if v.Endpoint == endpoint.Path {
 					foundAfter = true
@@ -1297,7 +1294,7 @@ func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove b
 			}
 		}
 		if !foundAfter {
-			res.After.Drives = append(res.After.Drives, madmin.HealDriveInfo{
+			result.After.Drives = append(result.After.Drives, madmin.HealDriveInfo{
 				UUID:     "",
 				Endpoint: endpoint.String(),
 				State:    madmin.DriveStateOffline,
@@ -1306,14 +1303,12 @@ func (s *xlSets) HealBucket(ctx context.Context, bucket string, dryRun, remove b
 	}
 
 	// Check if we had quorum to write, if not return an appropriate error.
-	_, afterDriveOnline := res.GetOnlineCounts()
+	_, afterDriveOnline := result.GetOnlineCounts()
 	if afterDriveOnline < ((s.setCount*s.drivesPerSet)/2)+1 {
-		return nil, toObjectErr(errXLWriteQuorum, bucket)
+		return result, toObjectErr(errXLWriteQuorum, bucket)
 	}
 
-	results = append(results, res)
-
-	return results, nil
+	return result, nil
 }
 
 // HealObject - heals inconsistent object on a hashedSet based on object name.

cmd/xl-v1-healing.go

@@ -20,7 +20,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"path"
 	"sync"
 	"time"
 
@@ -42,7 +41,7 @@ func (xl xlObjects) HealFormat(ctx context.Context, dryRun bool) (madmin.HealRes
 // also heals the missing entries for bucket metadata files
 // `policy.json, notification.xml, listeners.json`.
 func (xl xlObjects) HealBucket(ctx context.Context, bucket string, dryRun, remove bool) (
-	results []madmin.HealResultItem, err error) {
+	result madmin.HealResultItem, err error) {
 
 	storageDisks := xl.getDisks()
 
@@ -50,17 +49,7 @@ func (xl xlObjects) HealBucket(ctx context.Context, bucket string, dryRun, remov
 	writeQuorum := len(storageDisks)/2 + 1
 
 	// Heal bucket.
-	var result madmin.HealResultItem
-	result, err = healBucket(ctx, storageDisks, bucket, writeQuorum, dryRun)
-	if err != nil {
-		return nil, err
-	}
-	results = append(results, result)
-
-	// Proceed to heal bucket metadata.
-	metaResults, err := healBucketMetadata(xl, bucket, dryRun, remove)
-	results = append(results, metaResults...)
-	return results, err
+	return healBucket(ctx, storageDisks, bucket, writeQuorum, dryRun)
 }
 
 // Heal bucket - create buckets on disks where it does not exist.
@@ -157,51 +146,6 @@ func healBucket(ctx context.Context, storageDisks []StorageAPI, bucket string, w
 	return res, reducedErr
 }
 
-// Heals all the metadata associated for a given bucket, this function
-// heals `policy.json`, `notification.xml` and `listeners.json`.
-func healBucketMetadata(xl xlObjects, bucket string, dryRun, remove bool) (
-	results []madmin.HealResultItem, err error) {
-
-	healBucketMetaFn := func(metaPath string) error {
-		reqInfo := &logger.ReqInfo{BucketName: bucket}
-		ctx := logger.SetReqInfo(context.Background(), reqInfo)
-		result, healErr := xl.HealObject(ctx, minioMetaBucket, metaPath, dryRun, remove)
-		// If object is not found, skip the file.
-		if isErrObjectNotFound(healErr) {
-			return nil
-		}
-		if healErr != nil {
-			return healErr
-		}
-		result.Type = madmin.HealItemBucketMetadata
-		results = append(results, result)
-		return nil
-	}
-
-	// Heal `policy.json` for missing entries, ignores if
-	// `policy.json` is not found.
-	policyPath := pathJoin(bucketConfigPrefix, bucket, bucketPolicyConfig)
-	err = healBucketMetaFn(policyPath)
-	if err != nil {
-		return results, err
-	}
-
-	// Heal `notification.xml` for missing entries, ignores if
-	// `notification.xml` is not found.
-	nConfigPath := path.Join(bucketConfigPrefix, bucket,
-		bucketNotificationConfig)
-	err = healBucketMetaFn(nConfigPath)
-	if err != nil {
-		return results, err
-	}
-
-	// Heal `listeners.json` for missing entries, ignores if
-	// `listeners.json` is not found.
-	lConfigPath := path.Join(bucketConfigPrefix, bucket, bucketListenerConfig)
-	err = healBucketMetaFn(lConfigPath)
-	return results, err
-}
-
 // listAllBuckets lists all buckets from all disks. It also
 // returns the occurrence of each buckets in all disks
 func listAllBuckets(storageDisks []StorageAPI) (buckets map[string]VolInfo,