re-implement data usage crawler to be more efficient (#9075)

Implementation overview: 

https://gist.github.com/klauspost/1801c858d5e0df391114436fdad6987b

Makefile

@@ -22,7 +22,7 @@ getdeps:
 ifeq ($(GOARCH),s390x)
 	@which staticcheck 1>/dev/null || (echo "Installing staticcheck" && GO111MODULE=off go get honnef.co/go/tools/cmd/staticcheck)
 else
-	@which staticcheck 1>/dev/null || (echo "Installing staticcheck" && wget --quiet https://github.com/dominikh/go-tools/releases/download/2019.2.3/staticcheck_${GOOS}_${GOARCH}.tar.gz && tar xf staticcheck_${GOOS}_${GOARCH}.tar.gz && mv staticcheck/staticcheck ${GOPATH}/bin/staticcheck && chmod +x ${GOPATH}/bin/staticcheck && rm -f staticcheck_${GOOS}_${GOARCH}.tar.gz && rm -rf staticcheck)
+	@which staticcheck 1>/dev/null || (echo "Installing staticcheck" && wget --quiet https://github.com/dominikh/go-tools/releases/download/2020.1.3/staticcheck_${GOOS}_${GOARCH}.tar.gz && tar xf staticcheck_${GOOS}_${GOARCH}.tar.gz && mv staticcheck/staticcheck ${GOPATH}/bin/staticcheck && chmod +x ${GOPATH}/bin/staticcheck && rm -f staticcheck_${GOOS}_${GOARCH}.tar.gz && rm -rf staticcheck)
 endif
 	@which misspell 1>/dev/null || (echo "Installing misspell" && GO111MODULE=off go get -u github.com/client9/misspell/cmd/misspell)
 

browser/staticcheck.conf

@@ -0,0 +1 @@
+checks = ["all", "-ST1005", "-ST1000", "-SA4000", "-SA9004", "-SA1019", "-SA1008", "-U1000", "-ST1003", "-ST1018"]

cmd/admin-heal-ops.go

@@ -106,12 +106,12 @@ func initHealState() *allHealState {
 		healSeqMap: make(map[string]*healSequence),
 	}
 
-	go healState.periodicHealSeqsClean()
+	go healState.periodicHealSeqsClean(GlobalContext)
 
 	return healState
 }
 
-func (ahs *allHealState) periodicHealSeqsClean() {
+func (ahs *allHealState) periodicHealSeqsClean(ctx context.Context) {
 	// Launch clean-up routine to remove this heal sequence (after
 	// it ends) from the global state after timeout has elapsed.
 	ticker := time.NewTicker(time.Minute * 5)
@@ -127,7 +127,7 @@ func (ahs *allHealState) periodicHealSeqsClean() {
 				}
 			}
 			ahs.Unlock()
-		case <-GlobalServiceDoneCh:
+		case <-ctx.Done():
 			// server could be restarting - need
 			// to exit immediately
 			return
@@ -369,7 +369,7 @@ func newHealSequence(bucket, objPrefix, clientAddr string,
 
 	reqInfo := &logger.ReqInfo{RemoteHost: clientAddr, API: "Heal", BucketName: bucket}
 	reqInfo.AppendTags("prefix", objPrefix)
-	ctx := logger.SetReqInfo(context.Background(), reqInfo)
+	ctx := logger.SetReqInfo(GlobalContext, reqInfo)
 
 	return &healSequence{
 		bucket:         bucket,
@@ -603,7 +603,7 @@ func (h *healSequence) healItemsFromSourceCh() error {
 			h.lastHealActivity = UTCNow()
 		case <-h.traverseAndHealDoneCh:
 			return nil
-		case <-GlobalServiceDoneCh:
+		case <-h.ctx.Done():
 			return nil
 		}
 	}
@@ -630,11 +630,6 @@ func (h *healSequence) healItems(bucketsOnly bool) error {
 		return err
 	}
 
-	// Start healing the background ops prefix.
-	if err := h.healMinioSysMeta(backgroundOpsMetaPrefix)(); err != nil {
-		logger.LogIf(h.ctx, err)
-	}
-
 	// Heal buckets and objects
 	return h.healBuckets(bucketsOnly)
 }

cmd/config-current.go

@@ -26,7 +26,6 @@ import (
 	"github.com/minio/minio/cmd/config/cache"
 	"github.com/minio/minio/cmd/config/compress"
 	"github.com/minio/minio/cmd/config/etcd"
-	xetcd "github.com/minio/minio/cmd/config/etcd"
 	"github.com/minio/minio/cmd/config/etcd/dns"
 	xldap "github.com/minio/minio/cmd/config/identity/ldap"
 	"github.com/minio/minio/cmd/config/identity/openid"
@@ -304,13 +303,13 @@ func lookupConfigs(s config.Config) {
 		}
 	}
 
-	etcdCfg, err := xetcd.LookupConfig(s[config.EtcdSubSys][config.Default], globalRootCAs)
+	etcdCfg, err := etcd.LookupConfig(s[config.EtcdSubSys][config.Default], globalRootCAs)
 	if err != nil {
 		logger.LogIf(ctx, fmt.Errorf("Unable to initialize etcd config: %w", err))
 	}
 
 	if etcdCfg.Enabled {
-		globalEtcdClient, err = xetcd.New(etcdCfg)
+		globalEtcdClient, err = etcd.New(etcdCfg)
 		if err != nil {
 			logger.LogIf(ctx, fmt.Errorf("Unable to initialize etcd config: %w", err))
 		}

cmd/config/errors-utils.go

@@ -46,7 +46,7 @@ func (u Err) Clone() Err {
 	}
 }
 
-// Return the error message
+// Error returns the error message
 func (u Err) Error() string {
 	if u.detail == "" {
 		if u.msg != "" {

cmd/config/etcd/dns/etcd_dns.go

@@ -60,11 +60,7 @@ func (c *CoreDNS) List() (map[string][]SrvRecord, error) {
 			if record.Key == "" {
 				continue
 			}
-			if _, ok := srvRecords[record.Key]; ok {
+			srvRecords[record.Key] = append(srvRecords[record.Key], record)
-				srvRecords[record.Key] = append(srvRecords[record.Key], record)
-			} else {
-				srvRecords[record.Key] = []SrvRecord{record}
-			}
 		}
 	}
 	return srvRecords, nil

cmd/data-usage-cache.go

@@ -0,0 +1,521 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"path"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/cespare/xxhash/v2"
+	"github.com/minio/minio/cmd/logger"
+	"github.com/minio/minio/pkg/color"
+	"github.com/minio/minio/pkg/hash"
+	"github.com/tinylib/msgp/msgp"
+)
+
+const dataUsageHashLen = 8
+
+//go:generate msgp -file $GOFILE -unexported
+
+// dataUsageHash is the hash type used.
+type dataUsageHash uint64
+
+// sizeHistogram is a size histogram.
+type sizeHistogram [dataUsageBucketLen]uint64
+
+//msgp:tuple dataUsageEntry
+type dataUsageEntry struct {
+	// These fields do no include any children.
+	Size     int64
+	Objects  uint64
+	ObjSizes sizeHistogram
+
+	Children dataUsageHashMap
+}
+
+//msgp:ignore dataUsageEntryInfo
+type dataUsageEntryInfo struct {
+	Name   string
+	Parent string
+	Entry  dataUsageEntry
+}
+
+type dataUsageCacheInfo struct {
+	// Name of the bucket. Also root element.
+	Name       string
+	LastUpdate time.Time
+	NextCycle  uint8
+}
+
+// merge other data usage entry into this, excluding children.
+func (e *dataUsageEntry) merge(other dataUsageEntry) {
+	e.Objects += other.Objects
+	e.Size += other.Size
+	for i, v := range other.ObjSizes[:] {
+		e.ObjSizes[i] += v
+	}
+}
+
+// mod returns true if the hash mod cycles == cycle.
+func (h dataUsageHash) mod(cycle uint8, cycles uint8) bool {
+	return uint8(h)%cycles == cycle%cycles
+}
+
+// addChildString will add a child based on its name.
+// If it already exists it will not be added again.
+func (e *dataUsageEntry) addChildString(name string) {
+	e.addChild(hashPath(name))
+}
+
+// addChild will add a child based on its hash.
+// If it already exists it will not be added again.
+func (e *dataUsageEntry) addChild(hash dataUsageHash) {
+	if _, ok := e.Children[hash]; ok {
+		return
+	}
+	if e.Children == nil {
+		e.Children = make(dataUsageHashMap, 1)
+	}
+	e.Children[hash] = struct{}{}
+}
+
+// find a path in the cache.
+// Returns nil if not found.
+func (d *dataUsageCache) find(path string) *dataUsageEntry {
+	due, ok := d.Cache[hashPath(path)]
+	if !ok {
+		return nil
+	}
+	return &due
+}
+
+// dui converts the flattened version of the path to DataUsageInfo.
+func (d *dataUsageCache) dui(path string, buckets []BucketInfo) DataUsageInfo {
+	e := d.find(path)
+	if e == nil {
+		return DataUsageInfo{LastUpdate: time.Now()}
+	}
+	flat := d.flatten(*e)
+	return DataUsageInfo{
+		LastUpdate:            d.Info.LastUpdate,
+		ObjectsCount:          flat.Objects,
+		ObjectsTotalSize:      uint64(flat.Size),
+		ObjectsSizesHistogram: flat.ObjSizes.asMap(),
+		BucketsCount:          uint64(len(e.Children)),
+		BucketsSizes:          d.pathSizes(buckets),
+	}
+}
+
+// replace will add or replace an entry in the cache.
+// If a parent is specified it will be added to that if not already there.
+// If the parent does not exist, it will be added.
+func (d *dataUsageCache) replace(path, parent string, e dataUsageEntry) {
+	hash := hashPath(path)
+	if d.Cache == nil {
+		d.Cache = make(map[dataUsageHash]dataUsageEntry, 100)
+	}
+	d.Cache[hash] = e
+	if parent != "" {
+		phash := hashPath(parent)
+		p := d.Cache[phash]
+		p.addChild(hash)
+		d.Cache[phash] = p
+	}
+}
+
+// replaceHashed add or replaces an entry to the cache based on its hash.
+// If a parent is specified it will be added to that if not already there.
+// If the parent does not exist, it will be added.
+func (d *dataUsageCache) replaceHashed(hash dataUsageHash, parent *dataUsageHash, e dataUsageEntry) {
+	if d.Cache == nil {
+		d.Cache = make(map[dataUsageHash]dataUsageEntry, 100)
+	}
+	d.Cache[hash] = e
+	if parent != nil {
+		p := d.Cache[*parent]
+		p.addChild(hash)
+		d.Cache[*parent] = p
+	}
+}
+
+// StringAll returns a detailed string representation of all entries in the cache.
+func (d *dataUsageCache) StringAll() string {
+	s := fmt.Sprintf("info:%+v\n", d.Info)
+	for k, v := range d.Cache {
+		s += fmt.Sprintf("\t%v: %+v\n", k, v)
+	}
+	return strings.TrimSpace(s)
+}
+
+// String returns a human readable representation of the string.
+func (h dataUsageHash) String() string {
+	return fmt.Sprintf("%x", uint64(h))
+}
+
+// flatten all children of the root into the root element and return it.
+func (d *dataUsageCache) flatten(root dataUsageEntry) dataUsageEntry {
+	for id := range root.Children {
+		e := d.Cache[id]
+		if len(e.Children) > 0 {
+			e = d.flatten(e)
+		}
+		root.merge(e)
+	}
+	root.Children = nil
+	return root
+}
+
+// add a size to the histogram.
+func (h *sizeHistogram) add(size int64) {
+	// Fetch the histogram interval corresponding
+	// to the passed object size.
+	for i, interval := range ObjectsHistogramIntervals {
+		if size >= interval.start && size <= interval.end {
+			h[i]++
+			break
+		}
+	}
+}
+
+// asMap returns the map as a map[string]uint64.
+func (h *sizeHistogram) asMap() map[string]uint64 {
+	res := make(map[string]uint64, 7)
+	for i, count := range h {
+		res[ObjectsHistogramIntervals[i].name] = count
+	}
+	return res
+}
+
+// pathSizes returns the path sizes as a map.
+func (d *dataUsageCache) pathSizes(buckets []BucketInfo) map[string]uint64 {
+	var dst = make(map[string]uint64, len(buckets))
+	for _, bucket := range buckets {
+		e := d.find(bucket.Name)
+		if e == nil {
+			if dataUsageDebug {
+				logger.Info(color.Green("data-usage:")+" Bucket not found in cache: %v", bucket.Name)
+			}
+			continue
+		}
+		flat := d.flatten(*e)
+		dst[bucket.Name] = uint64(flat.Size)
+	}
+	return dst
+}
+
+// sizeRecursive returns the path as a flattened entry.
+func (d *dataUsageCache) sizeRecursive(path string) *dataUsageEntry {
+	root := d.find(path)
+	if root == nil || len(root.Children) == 0 {
+		return root
+	}
+	flat := d.flatten(*root)
+	return &flat
+}
+
+// dataUsageCache contains a cache of data usage entries.
+//msgp:ignore dataUsageCache
+type dataUsageCache struct {
+	Info  dataUsageCacheInfo
+	Cache map[dataUsageHash]dataUsageEntry
+}
+
+// root returns the root of the cache.
+func (d *dataUsageCache) root() *dataUsageEntry {
+	return d.find(d.Info.Name)
+}
+
+// rootHash returns the root of the cache.
+func (d *dataUsageCache) rootHash() dataUsageHash {
+	return hashPath(d.Info.Name)
+}
+
+// clone returns a copy of the cache with no references to the existing.
+func (d *dataUsageCache) clone() dataUsageCache {
+	clone := dataUsageCache{
+		Info:  d.Info,
+		Cache: make(map[dataUsageHash]dataUsageEntry, len(d.Cache)),
+	}
+	for k, v := range d.Cache {
+		clone.Cache[k] = v
+	}
+	return clone
+}
+
+// merge root of other into d.
+// children of root will be flattened before being merged.
+// Last update time will be set to the last updated.
+func (d *dataUsageCache) merge(other dataUsageCache) {
+	existingRoot := d.root()
+	otherRoot := other.root()
+	if existingRoot == nil && otherRoot == nil {
+		return
+	}
+	if otherRoot == nil {
+		return
+	}
+	if existingRoot == nil {
+		*d = other.clone()
+		return
+	}
+	if other.Info.LastUpdate.After(d.Info.LastUpdate) {
+		d.Info.LastUpdate = other.Info.LastUpdate
+	}
+	existingRoot.merge(*otherRoot)
+	eHash := d.rootHash()
+	for key := range otherRoot.Children {
+		entry := other.Cache[key]
+		flat := other.flatten(entry)
+		existing := d.Cache[key]
+		// If not found, merging simply adds.
+		existing.merge(flat)
+		d.replaceHashed(key, &eHash, existing)
+	}
+}
+
+// load the cache content with name from minioMetaBackgroundOpsBucket.
+// Only backend errors are returned as errors.
+// If the object is not found or unable to deserialize d is cleared and nil error is returned.
+func (d *dataUsageCache) load(ctx context.Context, store ObjectLayer, name string) error {
+	var buf bytes.Buffer
+	err := store.GetObject(ctx, dataUsageBucket, name, 0, -1, &buf, "", ObjectOptions{})
+	if err != nil {
+		if !isErrObjectNotFound(err) {
+			return toObjectErr(err, dataUsageBucket, name)
+		}
+		*d = dataUsageCache{}
+		return nil
+	}
+	err = d.deserialize(buf.Bytes())
+	if err != nil {
+		*d = dataUsageCache{}
+		logger.LogIf(ctx, err)
+	}
+	return nil
+}
+
+// save the content of the cache to minioMetaBackgroundOpsBucket with the provided name.
+func (d *dataUsageCache) save(ctx context.Context, store ObjectLayer, name string) error {
+	b := d.serialize()
+	size := int64(len(b))
+	r, err := hash.NewReader(bytes.NewReader(b), size, "", "", size, false)
+	if err != nil {
+		return err
+	}
+
+	_, err = store.PutObject(ctx,
+		dataUsageBucket,
+		name,
+		NewPutObjReader(r, nil, nil),
+		ObjectOptions{})
+	return err
+}
+
+// dataUsageCacheVer indicates the cache version.
+// Bumping the cache version will drop data from previous versions
+// and write new data with the new version.
+const dataUsageCacheVer = 1
+
+// serialize the contents of the cache.
+func (d *dataUsageCache) serialize() []byte {
+	// Alloc pessimistically
+	// dataUsageCacheVer
+	due := dataUsageEntry{}
+	msgLen := 1
+	msgLen += d.Info.Msgsize()
+	// len(d.Cache)
+	msgLen += binary.MaxVarintLen64
+	// Hashes (one for key, assume 1 child/node)
+	msgLen += len(d.Cache) * dataUsageHashLen * 2
+	msgLen += len(d.Cache) * due.Msgsize()
+
+	// Create destination buffer...
+	dst := make([]byte, 0, msgLen)
+
+	var n int
+	tmp := make([]byte, 1024)
+	// byte: version.
+	dst = append(dst, dataUsageCacheVer)
+	// Info...
+	dst, err := d.Info.MarshalMsg(dst)
+	if err != nil {
+		panic(err)
+	}
+	n = binary.PutUvarint(tmp, uint64(len(d.Cache)))
+	dst = append(dst, tmp[:n]...)
+
+	for k, v := range d.Cache {
+		// Put key
+		binary.LittleEndian.PutUint64(tmp[:dataUsageHashLen], uint64(k))
+		dst = append(dst, tmp[:8]...)
+		tmp, err = v.MarshalMsg(tmp[:0])
+		if err != nil {
+			panic(err)
+		}
+		// key, value pairs.
+		dst = append(dst, tmp...)
+
+	}
+	return dst
+}
+
+// deserialize the supplied byte slice into the cache.
+func (d *dataUsageCache) deserialize(b []byte) error {
+	if len(b) < 1 {
+		return io.ErrUnexpectedEOF
+	}
+	switch b[0] {
+	case 1:
+	default:
+		return fmt.Errorf("dataUsageCache: unknown version: %d", int(b[0]))
+	}
+	b = b[1:]
+
+	// Info...
+	b, err := d.Info.UnmarshalMsg(b)
+	if err != nil {
+		return err
+	}
+	cacheLen, n := binary.Uvarint(b)
+	if n <= 0 {
+		return fmt.Errorf("dataUsageCache: reading cachelen, n <= 0 ")
+	}
+	b = b[n:]
+	d.Cache = make(map[dataUsageHash]dataUsageEntry, cacheLen)
+
+	for i := 0; i < int(cacheLen); i++ {
+		if len(b) <= dataUsageHashLen {
+			return io.ErrUnexpectedEOF
+		}
+		k := binary.LittleEndian.Uint64(b[:dataUsageHashLen])
+		b = b[dataUsageHashLen:]
+		var v dataUsageEntry
+		b, err = v.UnmarshalMsg(b)
+		if err != nil {
+			return err
+		}
+		d.Cache[dataUsageHash(k)] = v
+	}
+	return nil
+}
+
+// Trim this from start+end of hashes.
+var hashPathCutSet = dataUsageRoot
+
+func init() {
+	if dataUsageRoot != string(filepath.Separator) {
+		hashPathCutSet = dataUsageRoot + string(filepath.Separator)
+	}
+}
+
+// hashPath calculates a hash of the provided string.
+func hashPath(data string) dataUsageHash {
+	if data != dataUsageRoot {
+		data = strings.Trim(data, hashPathCutSet)
+	}
+	data = path.Clean(data)
+	return dataUsageHash(xxhash.Sum64String(data))
+}
+
+//msgp:ignore dataUsageEntryInfo
+type dataUsageHashMap map[dataUsageHash]struct{}
+
+// MarshalMsg implements msgp.Marshaler
+func (d dataUsageHashMap) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, d.Msgsize())
+
+	// Write bin header manually
+	const mbin32 uint8 = 0xc6
+	sz := uint32(len(d)) * dataUsageHashLen
+	o = append(o, mbin32, byte(sz>>24), byte(sz>>16), byte(sz>>8), byte(sz))
+
+	var tmp [dataUsageHashLen]byte
+	for k := range d {
+		binary.LittleEndian.PutUint64(tmp[:], uint64(k))
+		o = append(o, tmp[:]...)
+	}
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (d dataUsageHashMap) Msgsize() (s int) {
+	s = 5 + len(d)*dataUsageHashLen
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (d *dataUsageHashMap) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var hashes []byte
+	hashes, bts, err = msgp.ReadBytesZC(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "dataUsageHashMap")
+		return
+	}
+
+	var dst = make(dataUsageHashMap, len(hashes)/dataUsageHashLen)
+	for len(hashes) >= dataUsageHashLen {
+		dst[dataUsageHash(binary.LittleEndian.Uint64(hashes[:dataUsageHashLen]))] = struct{}{}
+		hashes = hashes[dataUsageHashLen:]
+	}
+	*d = dst
+	o = bts
+	return
+}
+
+func (d *dataUsageHashMap) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadBytesHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	var dst = make(dataUsageHashMap, zb0001)
+	var tmp [8]byte
+	for i := uint32(0); i < zb0001; i++ {
+		_, err = io.ReadFull(dc, tmp[:])
+		if err != nil {
+			err = msgp.WrapError(err, "dataUsageHashMap")
+			return
+		}
+		dst[dataUsageHash(binary.LittleEndian.Uint64(tmp[:]))] = struct{}{}
+	}
+	return nil
+}
+func (d dataUsageHashMap) EncodeMsg(en *msgp.Writer) (err error) {
+	err = en.WriteBytesHeader(uint32(len(d)) * dataUsageHashLen)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	var tmp [dataUsageHashLen]byte
+	for k := range d {
+		binary.LittleEndian.PutUint64(tmp[:], uint64(k))
+		_, err = en.Write(tmp[:])
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+	}
+	return nil
+}

cmd/data-usage-cache_gen.go

@@ -0,0 +1,447 @@
+package cmd
+
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
+
+import (
+	"github.com/tinylib/msgp/msgp"
+)
+
+// DecodeMsg implements msgp.Decodable
+func (z *dataUsageCacheInfo) DecodeMsg(dc *msgp.Reader) (err error) {
+	var field []byte
+	_ = field
+	var zb0001 uint32
+	zb0001, err = dc.ReadMapHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	for zb0001 > 0 {
+		zb0001--
+		field, err = dc.ReadMapKeyPtr()
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		switch msgp.UnsafeString(field) {
+		case "Name":
+			z.Name, err = dc.ReadString()
+			if err != nil {
+				err = msgp.WrapError(err, "Name")
+				return
+			}
+		case "LastUpdate":
+			z.LastUpdate, err = dc.ReadTime()
+			if err != nil {
+				err = msgp.WrapError(err, "LastUpdate")
+				return
+			}
+		case "NextCycle":
+			z.NextCycle, err = dc.ReadUint8()
+			if err != nil {
+				err = msgp.WrapError(err, "NextCycle")
+				return
+			}
+		default:
+			err = dc.Skip()
+			if err != nil {
+				err = msgp.WrapError(err)
+				return
+			}
+		}
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z dataUsageCacheInfo) EncodeMsg(en *msgp.Writer) (err error) {
+	// map header, size 3
+	// write "Name"
+	err = en.Append(0x83, 0xa4, 0x4e, 0x61, 0x6d, 0x65)
+	if err != nil {
+		return
+	}
+	err = en.WriteString(z.Name)
+	if err != nil {
+		err = msgp.WrapError(err, "Name")
+		return
+	}
+	// write "LastUpdate"
+	err = en.Append(0xaa, 0x4c, 0x61, 0x73, 0x74, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65)
+	if err != nil {
+		return
+	}
+	err = en.WriteTime(z.LastUpdate)
+	if err != nil {
+		err = msgp.WrapError(err, "LastUpdate")
+		return
+	}
+	// write "NextCycle"
+	err = en.Append(0xa9, 0x4e, 0x65, 0x78, 0x74, 0x43, 0x79, 0x63, 0x6c, 0x65)
+	if err != nil {
+		return
+	}
+	err = en.WriteUint8(z.NextCycle)
+	if err != nil {
+		err = msgp.WrapError(err, "NextCycle")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z dataUsageCacheInfo) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// map header, size 3
+	// string "Name"
+	o = append(o, 0x83, 0xa4, 0x4e, 0x61, 0x6d, 0x65)
+	o = msgp.AppendString(o, z.Name)
+	// string "LastUpdate"
+	o = append(o, 0xaa, 0x4c, 0x61, 0x73, 0x74, 0x55, 0x70, 0x64, 0x61, 0x74, 0x65)
+	o = msgp.AppendTime(o, z.LastUpdate)
+	// string "NextCycle"
+	o = append(o, 0xa9, 0x4e, 0x65, 0x78, 0x74, 0x43, 0x79, 0x63, 0x6c, 0x65)
+	o = msgp.AppendUint8(o, z.NextCycle)
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *dataUsageCacheInfo) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var field []byte
+	_ = field
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadMapHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	for zb0001 > 0 {
+		zb0001--
+		field, bts, err = msgp.ReadMapKeyZC(bts)
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		switch msgp.UnsafeString(field) {
+		case "Name":
+			z.Name, bts, err = msgp.ReadStringBytes(bts)
+			if err != nil {
+				err = msgp.WrapError(err, "Name")
+				return
+			}
+		case "LastUpdate":
+			z.LastUpdate, bts, err = msgp.ReadTimeBytes(bts)
+			if err != nil {
+				err = msgp.WrapError(err, "LastUpdate")
+				return
+			}
+		case "NextCycle":
+			z.NextCycle, bts, err = msgp.ReadUint8Bytes(bts)
+			if err != nil {
+				err = msgp.WrapError(err, "NextCycle")
+				return
+			}
+		default:
+			bts, err = msgp.Skip(bts)
+			if err != nil {
+				err = msgp.WrapError(err)
+				return
+			}
+		}
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z dataUsageCacheInfo) Msgsize() (s int) {
+	s = 1 + 5 + msgp.StringPrefixSize + len(z.Name) + 11 + msgp.TimeSize + 10 + msgp.Uint8Size
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *dataUsageEntry) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
+		return
+	}
+	z.Size, err = dc.ReadInt64()
+	if err != nil {
+		err = msgp.WrapError(err, "Size")
+		return
+	}
+	z.Objects, err = dc.ReadUint64()
+	if err != nil {
+		err = msgp.WrapError(err, "Objects")
+		return
+	}
+	var zb0002 uint32
+	zb0002, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err, "ObjSizes")
+		return
+	}
+	if zb0002 != uint32(dataUsageBucketLen) {
+		err = msgp.ArrayError{Wanted: uint32(dataUsageBucketLen), Got: zb0002}
+		return
+	}
+	for za0001 := range z.ObjSizes {
+		z.ObjSizes[za0001], err = dc.ReadUint64()
+		if err != nil {
+			err = msgp.WrapError(err, "ObjSizes", za0001)
+			return
+		}
+	}
+	err = z.Children.DecodeMsg(dc)
+	if err != nil {
+		err = msgp.WrapError(err, "Children")
+		return
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z *dataUsageEntry) EncodeMsg(en *msgp.Writer) (err error) {
+	// array header, size 4
+	err = en.Append(0x94)
+	if err != nil {
+		return
+	}
+	err = en.WriteInt64(z.Size)
+	if err != nil {
+		err = msgp.WrapError(err, "Size")
+		return
+	}
+	err = en.WriteUint64(z.Objects)
+	if err != nil {
+		err = msgp.WrapError(err, "Objects")
+		return
+	}
+	err = en.WriteArrayHeader(uint32(dataUsageBucketLen))
+	if err != nil {
+		err = msgp.WrapError(err, "ObjSizes")
+		return
+	}
+	for za0001 := range z.ObjSizes {
+		err = en.WriteUint64(z.ObjSizes[za0001])
+		if err != nil {
+			err = msgp.WrapError(err, "ObjSizes", za0001)
+			return
+		}
+	}
+	err = z.Children.EncodeMsg(en)
+	if err != nil {
+		err = msgp.WrapError(err, "Children")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z *dataUsageEntry) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// array header, size 4
+	o = append(o, 0x94)
+	o = msgp.AppendInt64(o, z.Size)
+	o = msgp.AppendUint64(o, z.Objects)
+	o = msgp.AppendArrayHeader(o, uint32(dataUsageBucketLen))
+	for za0001 := range z.ObjSizes {
+		o = msgp.AppendUint64(o, z.ObjSizes[za0001])
+	}
+	o, err = z.Children.MarshalMsg(o)
+	if err != nil {
+		err = msgp.WrapError(err, "Children")
+		return
+	}
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *dataUsageEntry) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
+		return
+	}
+	z.Size, bts, err = msgp.ReadInt64Bytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Size")
+		return
+	}
+	z.Objects, bts, err = msgp.ReadUint64Bytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Objects")
+		return
+	}
+	var zb0002 uint32
+	zb0002, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "ObjSizes")
+		return
+	}
+	if zb0002 != uint32(dataUsageBucketLen) {
+		err = msgp.ArrayError{Wanted: uint32(dataUsageBucketLen), Got: zb0002}
+		return
+	}
+	for za0001 := range z.ObjSizes {
+		z.ObjSizes[za0001], bts, err = msgp.ReadUint64Bytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "ObjSizes", za0001)
+			return
+		}
+	}
+	bts, err = z.Children.UnmarshalMsg(bts)
+	if err != nil {
+		err = msgp.WrapError(err, "Children")
+		return
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *dataUsageEntry) Msgsize() (s int) {
+	s = 1 + msgp.Int64Size + msgp.Uint64Size + msgp.ArrayHeaderSize + (dataUsageBucketLen * (msgp.Uint64Size)) + z.Children.Msgsize()
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *dataUsageHash) DecodeMsg(dc *msgp.Reader) (err error) {
+	{
+		var zb0001 uint64
+		zb0001, err = dc.ReadUint64()
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		(*z) = dataUsageHash(zb0001)
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z dataUsageHash) EncodeMsg(en *msgp.Writer) (err error) {
+	err = en.WriteUint64(uint64(z))
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z dataUsageHash) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	o = msgp.AppendUint64(o, uint64(z))
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *dataUsageHash) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	{
+		var zb0001 uint64
+		zb0001, bts, err = msgp.ReadUint64Bytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		(*z) = dataUsageHash(zb0001)
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z dataUsageHash) Msgsize() (s int) {
+	s = msgp.Uint64Size
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *sizeHistogram) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != uint32(dataUsageBucketLen) {
+		err = msgp.ArrayError{Wanted: uint32(dataUsageBucketLen), Got: zb0001}
+		return
+	}
+	for za0001 := range z {
+		z[za0001], err = dc.ReadUint64()
+		if err != nil {
+			err = msgp.WrapError(err, za0001)
+			return
+		}
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z *sizeHistogram) EncodeMsg(en *msgp.Writer) (err error) {
+	err = en.WriteArrayHeader(uint32(dataUsageBucketLen))
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	for za0001 := range z {
+		err = en.WriteUint64(z[za0001])
+		if err != nil {
+			err = msgp.WrapError(err, za0001)
+			return
+		}
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z *sizeHistogram) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	o = msgp.AppendArrayHeader(o, uint32(dataUsageBucketLen))
+	for za0001 := range z {
+		o = msgp.AppendUint64(o, z[za0001])
+	}
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *sizeHistogram) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != uint32(dataUsageBucketLen) {
+		err = msgp.ArrayError{Wanted: uint32(dataUsageBucketLen), Got: zb0001}
+		return
+	}
+	for za0001 := range z {
+		z[za0001], bts, err = msgp.ReadUint64Bytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, za0001)
+			return
+		}
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z *sizeHistogram) Msgsize() (s int) {
+	s = msgp.ArrayHeaderSize + (dataUsageBucketLen * (msgp.Uint64Size))
+	return
+}

cmd/data-usage-cache_gen_test.go

@@ -0,0 +1,349 @@
+package cmd
+
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/tinylib/msgp/msgp"
+)
+
+func TestMarshalUnmarshaldataUsageCacheInfo(t *testing.T) {
+	v := dataUsageCacheInfo{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgdataUsageCacheInfo(b *testing.B) {
+	v := dataUsageCacheInfo{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgdataUsageCacheInfo(b *testing.B) {
+	v := dataUsageCacheInfo{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshaldataUsageCacheInfo(b *testing.B) {
+	v := dataUsageCacheInfo{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodedataUsageCacheInfo(t *testing.T) {
+	v := dataUsageCacheInfo{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodedataUsageCacheInfo Msgsize() is inaccurate")
+	}
+
+	vn := dataUsageCacheInfo{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodedataUsageCacheInfo(b *testing.B) {
+	v := dataUsageCacheInfo{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodedataUsageCacheInfo(b *testing.B) {
+	v := dataUsageCacheInfo{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestMarshalUnmarshaldataUsageEntry(t *testing.T) {
+	v := dataUsageEntry{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgdataUsageEntry(b *testing.B) {
+	v := dataUsageEntry{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgdataUsageEntry(b *testing.B) {
+	v := dataUsageEntry{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshaldataUsageEntry(b *testing.B) {
+	v := dataUsageEntry{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodedataUsageEntry(t *testing.T) {
+	v := dataUsageEntry{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodedataUsageEntry Msgsize() is inaccurate")
+	}
+
+	vn := dataUsageEntry{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodedataUsageEntry(b *testing.B) {
+	v := dataUsageEntry{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodedataUsageEntry(b *testing.B) {
+	v := dataUsageEntry{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestMarshalUnmarshalsizeHistogram(t *testing.T) {
+	v := sizeHistogram{}
+	bts, err := v.MarshalMsg(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	left, err := v.UnmarshalMsg(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after UnmarshalMsg(): %q", len(left), left)
+	}
+
+	left, err = msgp.Skip(bts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(left) > 0 {
+		t.Errorf("%d bytes left over after Skip(): %q", len(left), left)
+	}
+}
+
+func BenchmarkMarshalMsgsizeHistogram(b *testing.B) {
+	v := sizeHistogram{}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.MarshalMsg(nil)
+	}
+}
+
+func BenchmarkAppendMsgsizeHistogram(b *testing.B) {
+	v := sizeHistogram{}
+	bts := make([]byte, 0, v.Msgsize())
+	bts, _ = v.MarshalMsg(bts[0:0])
+	b.SetBytes(int64(len(bts)))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bts, _ = v.MarshalMsg(bts[0:0])
+	}
+}
+
+func BenchmarkUnmarshalsizeHistogram(b *testing.B) {
+	v := sizeHistogram{}
+	bts, _ := v.MarshalMsg(nil)
+	b.ReportAllocs()
+	b.SetBytes(int64(len(bts)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := v.UnmarshalMsg(bts)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func TestEncodeDecodesizeHistogram(t *testing.T) {
+	v := sizeHistogram{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+
+	m := v.Msgsize()
+	if buf.Len() > m {
+		t.Log("WARNING: TestEncodeDecodesizeHistogram Msgsize() is inaccurate")
+	}
+
+	vn := sizeHistogram{}
+	err := msgp.Decode(&buf, &vn)
+	if err != nil {
+		t.Error(err)
+	}
+
+	buf.Reset()
+	msgp.Encode(&buf, &v)
+	err = msgp.NewReader(&buf).Skip()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkEncodesizeHistogram(b *testing.B) {
+	v := sizeHistogram{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	en := msgp.NewWriter(msgp.Nowhere)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		v.EncodeMsg(en)
+	}
+	en.Flush()
+}
+
+func BenchmarkDecodesizeHistogram(b *testing.B) {
+	v := sizeHistogram{}
+	var buf bytes.Buffer
+	msgp.Encode(&buf, &v)
+	b.SetBytes(int64(buf.Len()))
+	rd := msgp.NewEndlessReader(buf.Bytes(), b)
+	dc := msgp.NewReader(rd)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		err := v.DecodeMsg(dc)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}

cmd/data-usage.go

@@ -20,23 +20,36 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"os"
-	"path/filepath"
+	"path"
+	"strconv"
 	"time"
 
 	jsoniter "github.com/json-iterator/go"
 	"github.com/minio/minio/cmd/config"
 	"github.com/minio/minio/cmd/logger"
+	"github.com/minio/minio/pkg/color"
 	"github.com/minio/minio/pkg/env"
 	"github.com/minio/minio/pkg/hash"
 )
 
 const (
-	dataUsageObjName       = "data-usage"
+	dataUsageObjName         = "usage.json"
-	dataUsageCrawlInterval = 12 * time.Hour
+	dataUsageCacheName       = "usage-cache.bin"
-	dataUsageCrawlConf     = "MINIO_DISK_USAGE_CRAWL"
+	dataUsageBucketCacheDir  = "usage-caches"
+	dataUsageCrawlConf       = "MINIO_DISK_USAGE_CRAWL"
+	dataUsageCrawlDelay      = "MINIO_DISK_USAGE_CRAWL_DELAY"
+	dataUsageDebug           = true
+	dataUsageSleepPerFolder  = 1 * time.Millisecond
+	dataUsageSleepDefMult    = 10.0
+	dataUsageUpdateDirCycles = 16
+	dataUsageRoot            = SlashSeparator
+	dataUsageBucket          = minioMetaBucket + SlashSeparator + bucketMetaPrefix
+	dataUsageStartDelay      = 5 * time.Minute // Time to wait on startup and between cycles.
 )
 
+// initDataUsageStats will start the crawler unless disabled.
 func initDataUsageStats() {
 	dataUsageEnabled, err := config.ParseBool(env.Get(dataUsageCrawlConf, config.EnableOn))
 	if err == nil && !dataUsageEnabled {
@@ -45,6 +58,7 @@ func initDataUsageStats() {
 	go runDataUsageInfoUpdateRoutine()
 }
 
+// runDataUsageInfoUpdateRoutine will contain the main crawler.
 func runDataUsageInfoUpdateRoutine() {
 	// Wait until the object layer is ready
 	var objAPI ObjectLayer
@@ -57,37 +71,13 @@ func runDataUsageInfoUpdateRoutine() {
 		break
 	}
 
-	runDataUsageInfo(context.Background(), objAPI, GlobalServiceDoneCh)
+	runDataUsageInfo(GlobalContext, objAPI)
-}
-
-// timeToNextCrawl returns the duration until next crawl should occur
-// this is validated by verifying the LastUpdate time.
-func timeToCrawl(ctx context.Context, objAPI ObjectLayer) time.Duration {
-	dataUsageInfo, err := loadDataUsageFromBackend(ctx, objAPI)
-	if err != nil {
-		// Upon an error wait for like 10
-		// seconds to start the crawler.
-		return 10 * time.Second
-	}
-	// File indeed doesn't exist when LastUpdate is zero
-	// so we have never crawled, start crawl right away.
-	if dataUsageInfo.LastUpdate.IsZero() {
-		return 1 * time.Second
-	}
-	timeSinceLastUpdate := UTCNow().Sub(dataUsageInfo.LastUpdate)
-	if timeSinceLastUpdate > dataUsageCrawlInterval {
-		// Waited long enough start crawl in a 1 second
-		return 1 * time.Second
-	}
-	// No crawling needed, ask the routine to wait until
-	// the daily interval 12hrs - delta between last update
-	// with current time.
-	return dataUsageCrawlInterval - timeSinceLastUpdate
 }
 
 var dataUsageLockTimeout = lifecycleLockTimeout
 
-func runDataUsageInfo(ctx context.Context, objAPI ObjectLayer, endCh <-chan struct{}) {
+func runDataUsageInfo(ctx context.Context, objAPI ObjectLayer) {
+	// Make sure only 1 crawler is running on the cluster.
 	locker := objAPI.NewNSLock(ctx, minioMetaBucket, "leader-data-usage-info")
 	for {
 		err := locker.GetLock(dataUsageLockTimeout)
@@ -99,47 +89,57 @@ func runDataUsageInfo(ctx context.Context, objAPI ObjectLayer, endCh <-chan stru
 		// data usage calculator role for its lifetime.
 		break
 	}
-
+	if dataUsageDebug {
+		logger.Info(color.Green("runDataUsageInfo:") + " Starting crawler master")
+	}
 	for {
-		wait := timeToCrawl(ctx, objAPI)
 		select {
-		case <-endCh:
+		case <-ctx.Done():
 			locker.Unlock()
 			return
-		case <-time.NewTimer(wait).C:
+			// Wait before starting next cycle and wait on startup.
-			// Crawl only when no previous crawl has occurred,
+		case <-time.NewTimer(dataUsageStartDelay).C:
-			// or its been too long since last crawl.
+			results := make(chan DataUsageInfo, 1)
-			err := storeDataUsageInBackend(ctx, objAPI, objAPI.CrawlAndGetDataUsage(ctx, endCh))
+			go storeDataUsageInBackend(ctx, objAPI, results)
+			err := objAPI.CrawlAndGetDataUsage(ctx, results)
+			close(results)
 			logger.LogIf(ctx, err)
 		}
 	}
 }
 
-func storeDataUsageInBackend(ctx context.Context, objAPI ObjectLayer, dataUsageInfo DataUsageInfo) error {
+// storeDataUsageInBackend will store all objects sent on the gui channel until closed.
-	dataUsageJSON, err := json.Marshal(dataUsageInfo)
+func storeDataUsageInBackend(ctx context.Context, objAPI ObjectLayer, gui <-chan DataUsageInfo) {
-	if err != nil {
+	for dataUsageInfo := range gui {
-		return err
+		dataUsageJSON, err := json.MarshalIndent(dataUsageInfo, "", "  ")
-	}
+		if err != nil {
+			logger.LogIf(ctx, err)
+			continue
+		}
+		if dataUsageDebug {
+			logger.Info(color.Green("data-usage:")+" Received update: %s", string(dataUsageJSON))
+		}
+		size := int64(len(dataUsageJSON))
+		r, err := hash.NewReader(bytes.NewReader(dataUsageJSON), size, "", "", size, false)
+		if err != nil {
+			logger.LogIf(ctx, err)
+			continue
+		}
 
-	size := int64(len(dataUsageJSON))
+		_, err = objAPI.PutObject(ctx, dataUsageBucket, dataUsageObjName, NewPutObjReader(r, nil, nil), ObjectOptions{})
-	r, err := hash.NewReader(bytes.NewReader(dataUsageJSON), size, "", "", size, false)
+		logger.LogIf(ctx, err)
-	if err != nil {
-		return err
 	}
-
-	_, err = objAPI.PutObject(ctx, minioMetaBackgroundOpsBucket, dataUsageObjName, NewPutObjReader(r, nil, nil), ObjectOptions{})
-	return err
 }
 
 func loadDataUsageFromBackend(ctx context.Context, objAPI ObjectLayer) (DataUsageInfo, error) {
 	var dataUsageInfoJSON bytes.Buffer
 
-	err := objAPI.GetObject(ctx, minioMetaBackgroundOpsBucket, dataUsageObjName, 0, -1, &dataUsageInfoJSON, "", ObjectOptions{})
+	err := objAPI.GetObject(ctx, dataUsageBucket, dataUsageObjName, 0, -1, &dataUsageInfoJSON, "", ObjectOptions{})
 	if err != nil {
 		if isErrObjectNotFound(err) {
 			return DataUsageInfo{}, nil
 		}
-		return DataUsageInfo{}, toObjectErr(err, minioMetaBackgroundOpsBucket, dataUsageObjName)
+		return DataUsageInfo{}, toObjectErr(err, dataUsageBucket, dataUsageObjName)
 	}
 
 	var dataUsageInfo DataUsageInfo
@@ -160,52 +160,295 @@ type Item struct {
 
 type getSizeFn func(item Item) (int64, error)
 
-func updateUsage(basePath string, doneCh <-chan struct{}, waitForLowActiveIO func(), getSize getSizeFn) DataUsageInfo {
+type cachedFolder struct {
-	var dataUsageInfo = DataUsageInfo{
+	name   string
-		BucketsSizes:          make(map[string]uint64),
+	parent *dataUsageHash
-		ObjectsSizesHistogram: make(map[string]uint64),
+}
+
+type folderScanner struct {
+	root               string
+	getSize            getSizeFn
+	oldCache           dataUsageCache
+	newCache           dataUsageCache
+	waitForLowActiveIO func()
+
+	newFolders      []cachedFolder
+	existingFolders []cachedFolder
+}
+
+// sleepDuration multiplies the duration d by x and sleeps if is more than 100 micro seconds.
+// sleep is limited to max 1 second.
+func sleepDuration(d time.Duration, x float64) {
+	// Don't sleep for really small amount of time
+	if d := time.Duration(float64(d) * x); d > time.Microsecond*100 {
+		if d > time.Second {
+			d = time.Second
+		}
+		time.Sleep(d)
 	}
+}
+
+// scanQueuedLevels will scan the provided folders.
+// Files found in the folders will be added to f.newCache.
+// If final is provided folders will be put into f.newFolders or f.existingFolders.
+// If final is not provided the folders found are returned from the function.
+func (f *folderScanner) scanQueuedLevels(ctx context.Context, folders []cachedFolder, final bool) ([]cachedFolder, error) {
+	var nextFolders []cachedFolder
+	delayMult := dataUsageSleepDefMult
+	if mult := os.Getenv(dataUsageCrawlDelay); mult != "" {
+		if d, err := strconv.ParseFloat(mult, 64); err == nil {
+			delayMult = d
+		}
+	}
+	done := ctx.Done()
+	for _, folder := range folders {
+		select {
+		case <-done:
+			return nil, ctx.Err()
+		default:
+		}
+		f.waitForLowActiveIO()
+		sleepDuration(dataUsageSleepPerFolder, delayMult)
+
+		cache := dataUsageEntry{}
+		thisHash := hashPath(folder.name)
+
+		err := readDirFn(path.Join(f.root, folder.name), func(entName string, typ os.FileMode) error {
+			// Parse
+			entName = path.Clean(path.Join(folder.name, entName))
+			bucket, _ := path2BucketObjectWithBasePath(f.root, entName)
+			if bucket == "" {
+				if dataUsageDebug {
+					logger.Info(color.Green("data-usage:")+" no bucket (%s,%s)", f.root, entName)
+				}
+				return nil
+			}
+
+			if isReservedOrInvalidBucket(bucket, false) {
+				if dataUsageDebug {
+					logger.Info(color.Green("data-usage:")+" invalid bucket: %v, entry: %v", bucket, entName)
+				}
+				return nil
+			}
+
+			select {
+			case <-done:
+				return ctx.Err()
+			default:
+			}
+
+			if typ&os.ModeDir != 0 {
+				h := hashPath(entName)
+				_, exists := f.oldCache.Cache[h]
+				cache.addChildString(entName)
+
+				this := cachedFolder{name: entName, parent: &thisHash}
+				cache.addChild(h)
+				if final {
+					if exists {
+						f.existingFolders = append(f.existingFolders, this)
+					} else {
+						f.newFolders = append(f.newFolders, this)
+					}
+				} else {
+					nextFolders = append(nextFolders, this)
+				}
+				return nil
+			}
+			f.waitForLowActiveIO()
+			// Dynamic time delay.
+			t := time.Now()
 
-	fastWalk(basePath, 1, doneCh, func(path string, typ os.FileMode) error {
+			// Get file size, ignore errors.
-		// Wait for I/O to go down.
+			size, err := f.getSize(Item{Path: path.Join(f.root, entName), Typ: typ})
-		waitForLowActiveIO()
+
+			sleepDuration(time.Since(t), delayMult)
+			if err == errSkipFile {
+				return nil
+			}
+			logger.LogIf(ctx, err)
+			cache.Size += size
+			cache.Objects++
+			cache.ObjSizes.add(size)
 
-		bucket, entry := path2BucketObjectWithBasePath(basePath, path)
-		if bucket == "" {
 			return nil
+		})
+		if err != nil {
+			return nil, err
 		}
+		f.newCache.replaceHashed(thisHash, folder.parent, cache)
+	}
+	return nextFolders, nil
+}
 
-		if isReservedOrInvalidBucket(bucket, false) {
+// deepScanFolder will deep scan a folder and return the size if no error occurs.
-			return filepath.SkipDir
+func (f *folderScanner) deepScanFolder(ctx context.Context, folder string) (*dataUsageEntry, error) {
+	var cache dataUsageEntry
+	delayMult := dataUsageSleepDefMult
+	if mult := os.Getenv(dataUsageCrawlDelay); mult != "" {
+		if d, err := strconv.ParseFloat(mult, 64); err == nil {
+			delayMult = d
 		}
+	}
+	done := ctx.Done()
 
-		if entry == "" && typ&os.ModeDir != 0 {
+	var addDir func(entName string, typ os.FileMode) error
-			dataUsageInfo.BucketsCount++
+	var dirStack = []string{f.root, folder}
-			dataUsageInfo.BucketsSizes[bucket] = 0
+
-			return nil
+	addDir = func(entName string, typ os.FileMode) error {
+		select {
+		case <-done:
+			return ctx.Err()
+		default:
 		}
 
+		f.waitForLowActiveIO()
 		if typ&os.ModeDir != 0 {
+			dirStack = append(dirStack, entName)
+			err := readDirFn(path.Join(dirStack...), addDir)
+			dirStack = dirStack[:len(dirStack)-1]
+			sleepDuration(dataUsageSleepPerFolder, delayMult)
+			return err
+		}
+		// Dynamic time delay.
+		t := time.Now()
+
+		// Get file size, ignore errors.
+		dirStack = append(dirStack, entName)
+		fileName := path.Join(dirStack...)
+		dirStack = dirStack[:len(dirStack)-1]
+
+		size, err := f.getSize(Item{Path: fileName, Typ: typ})
+
+		// Don't sleep for really small amount of time
+		sleepDuration(time.Since(t), delayMult)
+
+		if err == errSkipFile {
 			return nil
 		}
+		logger.LogIf(ctx, err)
+		cache.Size += size
+		cache.Objects++
+		cache.ObjSizes.add(size)
+		return nil
+	}
+	err := readDirFn(path.Join(dirStack...), addDir)
+	if err != nil {
+		return nil, err
+	}
+	return &cache, nil
+}
 
-		t := time.Now()
+// updateUsage will crawl the basepath+cache.Info.Name and return an updated cache.
-		size, err := getSize(Item{path, typ})
+// The returned cache will always be valid, but may not be updated from the existing.
-		// Use the response time of the getSize call to guess system load.
+// Before each operation waitForLowActiveIO is called which can be used to temporarily halt the crawler.
-		// Sleep equivalent time.
+// If the supplied context is canceled the function will return at the first chance.
-		if d := time.Since(t); d > 100*time.Microsecond {
+func updateUsage(ctx context.Context, basePath string, cache dataUsageCache, waitForLowActiveIO func(), getSize getSizeFn) (dataUsageCache, error) {
-			time.Sleep(d)
+	if cache.Info.Name == "" {
+		cache.Info.Name = dataUsageRoot
+	}
+	var logPrefix, logSuffix string
+	if dataUsageDebug {
+		logPrefix = color.Green("data-usage: ")
+		logSuffix = color.Blue(" - %v + %v", basePath, cache.Info.Name)
+	}
+	s := folderScanner{
+		root:               basePath,
+		getSize:            getSize,
+		oldCache:           cache,
+		newCache:           dataUsageCache{Info: cache.Info},
+		waitForLowActiveIO: waitForLowActiveIO,
+		newFolders:         nil,
+		existingFolders:    nil,
+	}
+
+	done := ctx.Done()
+	var flattenLevels = 3
+
+	// If we are scanning inside a bucket reduce depth by 1.
+	if cache.Info.Name != dataUsageRoot {
+		flattenLevels--
+	}
+	if dataUsageDebug {
+		logger.Info(logPrefix+"Cycle: %v"+logSuffix, cache.Info.NextCycle)
+	}
+
+	// Always scan flattenLevels deep. Cache root is level 0.
+	todo := []cachedFolder{{name: cache.Info.Name}}
+	for i := 0; i < flattenLevels; i++ {
+		if dataUsageDebug {
+			logger.Info(logPrefix+"Level %v, scanning %v directories."+logSuffix, i, len(todo))
 		}
+		select {
+		case <-done:
+			return cache, ctx.Err()
+		default:
+		}
+		var err error
+		todo, err = s.scanQueuedLevels(ctx, todo, i == flattenLevels-1)
 		if err != nil {
-			return errSkipFile
+			// No useful information...
+			return cache, err
 		}
+	}
 
-		dataUsageInfo.ObjectsCount++
+	if dataUsageDebug {
-		dataUsageInfo.ObjectsTotalSize += uint64(size)
+		logger.Info(logPrefix+"New folders: %v"+logSuffix, s.newFolders)
-		dataUsageInfo.BucketsSizes[bucket] += uint64(size)
+	}
-		dataUsageInfo.ObjectsSizesHistogram[objSizeToHistoInterval(uint64(size))]++
+	// Add new folders first
-		return nil
+	for _, folder := range s.newFolders {
-	})
+		select {
+		case <-done:
+			return s.newCache, ctx.Err()
+		default:
+		}
+		du, err := s.deepScanFolder(ctx, folder.name)
+		if err != nil {
+			logger.LogIf(ctx, err)
+			continue
+		}
+		if du == nil {
+			logger.LogIf(ctx, errors.New("data-usage: no disk usage provided"))
+			continue
+		}
+		s.newCache.replace(folder.name, "", *du)
+		// Add to parent manually
+		if folder.parent != nil {
+			parent := s.newCache.Cache[*folder.parent]
+			parent.addChildString(folder.name)
+		}
+	}
+
+	if dataUsageDebug {
+		logger.Info(logPrefix+"Existing folders: %v"+logSuffix, len(s.existingFolders))
+	}
+	// Do selective scanning of existing folders.
+	for _, folder := range s.existingFolders {
+		select {
+		case <-done:
+			return s.newCache, ctx.Err()
+		default:
+		}
+		h := hashPath(folder.name)
+		if !h.mod(s.oldCache.Info.NextCycle, dataUsageUpdateDirCycles) {
+			s.newCache.replaceHashed(h, folder.parent, s.oldCache.Cache[h])
+			continue
+		}
+
+		// Update on this cycle...
+		du, err := s.deepScanFolder(ctx, folder.name)
+		if err != nil {
+			logger.LogIf(ctx, err)
+			continue
+		}
+		if du == nil {
+			logger.LogIf(ctx, errors.New("data-usage: no disk usage provided"))
+			continue
+		}
+		s.newCache.replaceHashed(h, folder.parent, *du)
+	}
 
-	return dataUsageInfo
+	s.newCache.Info.LastUpdate = time.Now()
+	s.newCache.Info.NextCycle++
+	return s.newCache, nil
 }

cmd/data-usage_test.go

@@ -0,0 +1,664 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+type usageTestFile struct {
+	name string
+	size int
+}
+
+func Test_updateUsage(t *testing.T) {
+	base, err := ioutil.TempDir("", "Test_updateUsage")
+	if err != nil {
+		t.Skip(err)
+	}
+	defer os.RemoveAll(base)
+	var files = []usageTestFile{
+		{name: "rootfile", size: 10000},
+		{name: "rootfile2", size: 10000},
+		{name: "dir1/d1file", size: 2000},
+		{name: "dir2/d2file", size: 300},
+		{name: "dir1/dira/dafile", size: 100000},
+		{name: "dir1/dira/dbfile", size: 200000},
+		{name: "dir1/dira/dirasub/dcfile", size: 1000000},
+		{name: "dir1/dira/dirasub/sublevel3/dccccfile", size: 10},
+	}
+	createUsageTestFiles(t, base, files)
+
+	getSize := func(item Item) (i int64, err error) {
+		if item.Typ&os.ModeDir == 0 {
+			s, err := os.Stat(item.Path)
+			if err != nil {
+				return 0, err
+			}
+			return s.Size(), nil
+		}
+		return 0, nil
+	}
+	got, err := updateUsage(context.Background(), base, dataUsageCache{}, func() {}, getSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Test dirs
+	var want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		flatten    bool
+		oSizes     sizeHistogram
+	}{
+		{
+			path:    "/",
+			size:    1322310,
+			flatten: true,
+			objs:    8,
+			oSizes:  sizeHistogram{0: 2, 1: 6},
+		},
+		{
+			path:   "/",
+			size:   20000,
+			objs:   2,
+			oSizes: sizeHistogram{1: 2},
+		},
+		{
+			path:   "/dir1",
+			size:   2000,
+			objs:   1,
+			oSizes: sizeHistogram{1: 1},
+		},
+		{
+			path:    "/dir1/dira",
+			flatten: true,
+			size:    1300010,
+			objs:    4,
+			oSizes:  sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:    "/dir1/dira/",
+			flatten: true,
+			size:    1300010,
+			objs:    4,
+			oSizes:  sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:   "/dir1/dira",
+			size:   300000,
+			objs:   2,
+			oSizes: sizeHistogram{0: 0, 1: 2},
+		},
+		{
+			path:   "/dir1/dira/",
+			size:   300000,
+			objs:   2,
+			oSizes: sizeHistogram{0: 0, 1: 2},
+		},
+		{
+			path:  "/nonexistying",
+			isNil: true,
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if w.flatten {
+				*e = got.flatten(*e)
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	files = []usageTestFile{
+		{
+			name: "newfolder/afile",
+			size: 4,
+		},
+		{
+			name: "newfolder/anotherone",
+			size: 1,
+		},
+		{
+			name: "newfolder/anemptyone",
+			size: 0,
+		},
+		{
+			name: "dir1/fileindir1",
+			size: 20000,
+		},
+		{
+			name: "dir1/dirc/fileindirc",
+			size: 20000,
+		},
+		{
+			name: "rootfile3",
+			size: 1000,
+		},
+	}
+	createUsageTestFiles(t, base, files)
+	got, err = updateUsage(context.Background(), base, got, func() {}, getSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		flatten    bool
+		oSizes     sizeHistogram
+	}{
+		{
+			path:    "/",
+			size:    1363315,
+			flatten: true,
+			objs:    14,
+			oSizes:  sizeHistogram{0: 6, 1: 8},
+		},
+		{
+			path:   "/",
+			size:   21000,
+			objs:   3,
+			oSizes: sizeHistogram{0: 1, 1: 2},
+		},
+		{
+			path:   "/newfolder",
+			size:   5,
+			objs:   3,
+			oSizes: sizeHistogram{0: 3},
+		},
+		{
+			path:    "/dir1/dira",
+			size:    1300010,
+			flatten: true,
+			objs:    4,
+			oSizes:  sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:  "/nonexistying",
+			isNil: true,
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if w.flatten {
+				*e = got.flatten(*e)
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	files = []usageTestFile{
+		{
+			name: "dir1/dira/dirasub/fileindira2",
+			size: 200,
+		},
+	}
+
+	createUsageTestFiles(t, base, files)
+	err = os.RemoveAll(filepath.Join(base, "dir1/dira/dirasub/dcfile"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Changed dir must be picked up in this many cycles.
+	for i := 0; i < dataUsageUpdateDirCycles; i++ {
+		got, err = updateUsage(context.Background(), base, got, func() {}, getSize)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		flatten    bool
+		oSizes     sizeHistogram
+	}{
+		{
+			path:    "/",
+			size:    363515,
+			flatten: true,
+			objs:    14,
+			oSizes:  sizeHistogram{0: 7, 1: 7},
+		},
+		{
+			path:    "/dir1/dira",
+			size:    300210,
+			objs:    4,
+			flatten: true,
+			oSizes:  sizeHistogram{0: 2, 1: 2},
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if w.flatten {
+				*e = got.flatten(*e)
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	t.Log(got.StringAll())
+
+	t.Logf("Root, flat: %+v", got.flatten(*got.root()))
+	t.Logf("Root: %+v", *got.root())
+	t.Logf("/dir1/dira: %+v", *got.find("/dir1/dira"))
+
+}
+
+func Test_updateUsagePrefix(t *testing.T) {
+	base, err := ioutil.TempDir("", "Test_updateUsagePrefix")
+	if err != nil {
+		t.Skip(err)
+	}
+	base = filepath.Join(base, "bucket")
+	defer os.RemoveAll(base)
+	var files = []usageTestFile{
+		{name: "bucket/rootfile", size: 10000},
+		{name: "bucket/rootfile2", size: 10000},
+		{name: "bucket/dir1/d1file", size: 2000},
+		{name: "bucket/dir2/d2file", size: 300},
+		{name: "bucket/dir1/dira/dafile", size: 100000},
+		{name: "bucket/dir1/dira/dbfile", size: 200000},
+		{name: "bucket/dir1/dira/dirasub/dcfile", size: 1000000},
+		{name: "bucket/dir1/dira/dirasub/sublevel3/dccccfile", size: 10},
+	}
+	createUsageTestFiles(t, base, files)
+
+	getSize := func(item Item) (i int64, err error) {
+		if item.Typ&os.ModeDir == 0 {
+			s, err := os.Stat(item.Path)
+			if err != nil {
+				return 0, err
+			}
+			return s.Size(), nil
+		}
+		return 0, nil
+	}
+	got, err := updateUsage(context.Background(), base, dataUsageCache{Info: dataUsageCacheInfo{Name: "bucket"}}, func() {}, getSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Test dirs
+	var want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		oSizes     sizeHistogram
+	}{
+		{
+			path:   "flat",
+			size:   1322310,
+			objs:   8,
+			oSizes: sizeHistogram{0: 2, 1: 6},
+		},
+		{
+			path:   "bucket/",
+			size:   20000,
+			objs:   2,
+			oSizes: sizeHistogram{1: 2},
+		},
+		{
+			path:   "bucket/dir1",
+			size:   2000,
+			objs:   1,
+			oSizes: sizeHistogram{1: 1},
+		},
+		{
+			path:   "bucket/dir1/dira",
+			size:   1300010,
+			objs:   4,
+			oSizes: sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:   "bucket/dir1/dira/",
+			size:   1300010,
+			objs:   4,
+			oSizes: sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:  "bucket/nonexistying",
+			isNil: true,
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.path == "flat" {
+				f := got.flatten(*got.root())
+				e = &f
+			}
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	files = []usageTestFile{
+		{
+			name: "bucket/newfolder/afile",
+			size: 4,
+		},
+		{
+			name: "bucket/newfolder/anotherone",
+			size: 1,
+		},
+		{
+			name: "bucket/newfolder/anemptyone",
+			size: 0,
+		},
+		{
+			name: "bucket/dir1/fileindir1",
+			size: 20000,
+		},
+		{
+			name: "bucket/dir1/dirc/fileindirc",
+			size: 20000,
+		},
+		{
+			name: "bucket/rootfile3",
+			size: 1000,
+		},
+	}
+	createUsageTestFiles(t, base, files)
+	got, err = updateUsage(context.Background(), base, got, func() {}, getSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		oSizes     sizeHistogram
+	}{
+		{
+			path:   "flat",
+			size:   1363315,
+			objs:   14,
+			oSizes: sizeHistogram{0: 6, 1: 8},
+		},
+		{
+			path:   "bucket/",
+			size:   21000,
+			objs:   3,
+			oSizes: sizeHistogram{0: 1, 1: 2},
+		},
+		{
+			path:   "bucket/newfolder",
+			size:   5,
+			objs:   3,
+			oSizes: sizeHistogram{0: 3},
+		},
+		{
+			path:   "bucket/dir1/dira",
+			size:   1300010,
+			objs:   4,
+			oSizes: sizeHistogram{0: 1, 1: 3},
+		},
+		{
+			path:  "bucket/nonexistying",
+			isNil: true,
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.path == "flat" {
+				f := got.flatten(*got.root())
+				e = &f
+			}
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	files = []usageTestFile{
+		{
+			name: "bucket/dir1/dira/dirasub/fileindira2",
+			size: 200,
+		},
+	}
+
+	createUsageTestFiles(t, base, files)
+	err = os.RemoveAll(filepath.Join(base, "bucket/dir1/dira/dirasub/dcfile"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Changed dir must be picked up in this many cycles.
+	for i := 0; i < dataUsageUpdateDirCycles; i++ {
+		got, err = updateUsage(context.Background(), base, got, func() {}, getSize)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	want = []struct {
+		path       string
+		isNil      bool
+		size, objs int
+		oSizes     sizeHistogram
+	}{
+		{
+			path:   "flat",
+			size:   363515,
+			objs:   14,
+			oSizes: sizeHistogram{0: 7, 1: 7},
+		},
+		{
+			path:   "bucket/dir1/dira",
+			size:   300210,
+			objs:   4,
+			oSizes: sizeHistogram{0: 2, 1: 2},
+		},
+	}
+
+	for _, w := range want {
+		t.Run(w.path, func(t *testing.T) {
+			e := got.find(w.path)
+			if w.path == "flat" {
+				f := got.flatten(*got.root())
+				e = &f
+			}
+			if w.isNil {
+				if e != nil {
+					t.Error("want nil, got", e)
+				}
+				return
+			}
+			if e == nil {
+				t.Fatal("got nil result")
+			}
+			if e.Size != int64(w.size) {
+				t.Error("got size", e.Size, "want", w.size)
+			}
+			if e.Objects != uint64(w.objs) {
+				t.Error("got objects", e.Objects, "want", w.objs)
+			}
+			if e.ObjSizes != w.oSizes {
+				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
+			}
+		})
+	}
+
+	t.Log(got.StringAll())
+
+	t.Logf("Root, flat: %+v", got.flatten(*got.root()))
+	t.Logf("Root: %+v", *got.root())
+	t.Logf("bucket/dir1/dira: %+v", *got.find("bucket/dir1/dira"))
+}
+
+func createUsageTestFiles(t *testing.T, base string, files []usageTestFile) {
+	for _, f := range files {
+		err := os.MkdirAll(filepath.Dir(filepath.Join(base, f.name)), os.ModePerm)
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = ioutil.WriteFile(filepath.Join(base, f.name), make([]byte, f.size), os.ModePerm)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func Test_dataUsageCacheSerialize(t *testing.T) {
+	base, err := ioutil.TempDir("", "Test_dataUsageCacheSerialize")
+	if err != nil {
+		t.Skip(err)
+	}
+	defer os.RemoveAll(base)
+	var files = []usageTestFile{
+		{name: "rootfile", size: 10000},
+		{name: "rootfile2", size: 10000},
+		{name: "dir1/d1file", size: 2000},
+		{name: "dir2/d2file", size: 300},
+		{name: "dir1/dira/dafile", size: 100000},
+		{name: "dir1/dira/dbfile", size: 200000},
+		{name: "dir1/dira/dirasub/dcfile", size: 1000000},
+		{name: "dir1/dira/dirasub/sublevel3/dccccfile", size: 10},
+	}
+	createUsageTestFiles(t, base, files)
+
+	getSize := func(item Item) (i int64, err error) {
+		if item.Typ&os.ModeDir == 0 {
+			s, err := os.Stat(item.Path)
+			if err != nil {
+				return 0, err
+			}
+			return s.Size(), nil
+		}
+		return 0, nil
+	}
+	want, err := updateUsage(context.Background(), base, dataUsageCache{}, func() {}, getSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b := want.serialize()
+	t.Log("serialize -> ", len(b), "bytes")
+
+	var got dataUsageCache
+	err = got.deserialize(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Info.LastUpdate.IsZero() {
+		t.Error("lastupdate not set")
+	}
+
+	if fmt.Sprint(want) == fmt.Sprint(got) {
+		t.Fatalf("deserialize mismatch\nwant: %+v\ngot:  %+v", want, got)
+	}
+}

cmd/disk-cache.go

@@ -693,7 +693,7 @@ func newServerCacheObjects(ctx context.Context, config cache.Config) (CacheObjec
 	return c, nil
 }
 
-func (c *cacheObjects) gc(ctx context.Context, doneCh chan struct{}) {
+func (c *cacheObjects) gc(ctx context.Context, doneCh <-chan struct{}) {
 	ticker := time.NewTicker(cacheGCInterval)
 
 	defer ticker.Stop()

cmd/fastwalk.go

@@ -11,173 +11,12 @@ package cmd
 import (
 	"errors"
 	"os"
-	"path/filepath"
 	"strings"
-	"sync"
 )
 
 var errSkipFile = errors.New("fastwalk: skip this file")
 
-// Walk is a faster implementation of filepath.Walk.
+func readDirFn(dirName string, fn func(entName string, typ os.FileMode) error) error {
-//
-// filepath.Walk's design necessarily calls os.Lstat on each file,
-// even if the caller needs less info.
-// Many tools need only the type of each file.
-// On some platforms, this information is provided directly by the readdir
-// system call, avoiding the need to stat each file individually.
-// fastwalk_unix.go contains a fork of the syscall routines.
-//
-// See golang.org/issue/16399
-//
-// Walk walks the file tree rooted at root, calling walkFn for
-// each file or directory in the tree, including root.
-//
-// If fastWalk returns filepath.SkipDir, the directory is skipped.
-//
-// Unlike filepath.Walk:
-//   * file stat calls must be done by the user.
-//     The only provided metadata is the file type, which does not include
-//     any permission bits.
-//   * multiple goroutines stat the filesystem concurrently. The provided
-//     walkFn must be safe for concurrent use.
-//   * fastWalk can follow symlinks if walkFn returns the TraverseLink
-//     sentinel error. It is the walkFn's responsibility to prevent
-//     fastWalk from going into symlink cycles.
-func fastWalk(root string, nworkers int, doneCh <-chan struct{}, walkFn func(path string, typ os.FileMode) error) error {
-
-	// Make sure to wait for all workers to finish, otherwise
-	// walkFn could still be called after returning. This Wait call
-	// runs after close(e.donec) below.
-	var wg sync.WaitGroup
-	defer wg.Wait()
-
-	w := &walker{
-		fn:       walkFn,
-		enqueuec: make(chan walkItem, nworkers), // buffered for performance
-		workc:    make(chan walkItem, nworkers), // buffered for performance
-		donec:    make(chan struct{}),
-
-		// buffered for correctness & not leaking goroutines:
-		resc: make(chan error, nworkers),
-	}
-	defer close(w.donec)
-
-	for i := 0; i < nworkers; i++ {
-		wg.Add(1)
-		go w.doWork(&wg)
-	}
-
-	todo := []walkItem{{dir: root}}
-	out := 0
-	for {
-		workc := w.workc
-		var workItem walkItem
-		if len(todo) == 0 {
-			workc = nil
-		} else {
-			workItem = todo[len(todo)-1]
-		}
-		select {
-		case <-doneCh:
-			return nil
-		case workc <- workItem:
-			todo = todo[:len(todo)-1]
-			out++
-		case it := <-w.enqueuec:
-			todo = append(todo, it)
-		case err := <-w.resc:
-			out--
-			if err != nil {
-				return err
-			}
-			if out == 0 && len(todo) == 0 {
-				// It's safe to quit here, as long as the buffered
-				// enqueue channel isn't also readable, which might
-				// happen if the worker sends both another unit of
-				// work and its result before the other select was
-				// scheduled and both w.resc and w.enqueuec were
-				// readable.
-				select {
-				case it := <-w.enqueuec:
-					todo = append(todo, it)
-				default:
-					return nil
-				}
-			}
-		}
-	}
-}
-
-// doWork reads directories as instructed (via workc) and runs the
-// user's callback function.
-func (w *walker) doWork(wg *sync.WaitGroup) {
-	defer wg.Done()
-	for {
-		select {
-		case <-w.donec:
-			return
-		case it := <-w.workc:
-			select {
-			case <-w.donec:
-				return
-			case w.resc <- w.walk(it.dir, !it.callbackDone):
-			}
-		}
-	}
-}
-
-type walker struct {
-	fn func(path string, typ os.FileMode) error
-
-	donec    chan struct{} // closed on fastWalk's return
-	workc    chan walkItem // to workers
-	enqueuec chan walkItem // from workers
-	resc     chan error    // from workers
-}
-
-type walkItem struct {
-	dir          string
-	callbackDone bool // callback already called; don't do it again
-}
-
-func (w *walker) enqueue(it walkItem) {
-	select {
-	case w.enqueuec <- it:
-	case <-w.donec:
-	}
-}
-
-var stringsBuilderPool = sync.Pool{
-	New: func() interface{} {
-		return &strings.Builder{}
-	},
-}
-
-func (w *walker) onDirEnt(dirName, baseName string, typ os.FileMode) error {
-	builder := stringsBuilderPool.Get().(*strings.Builder)
-	defer func() {
-		builder.Reset()
-		stringsBuilderPool.Put(builder)
-	}()
-
-	builder.WriteString(dirName)
-	if !strings.HasSuffix(dirName, SlashSeparator) {
-		builder.WriteString(SlashSeparator)
-	}
-	builder.WriteString(baseName)
-	if typ == os.ModeDir {
-		w.enqueue(walkItem{dir: builder.String()})
-		return nil
-	}
-
-	err := w.fn(builder.String(), typ)
-	if err == filepath.SkipDir || err == errSkipFile {
-		return nil
-	}
-	return err
-}
-
-func readDirFn(dirName string, fn func(dirName, entName string, typ os.FileMode) error) error {
 	fis, err := readDir(dirName)
 	if err != nil {
 		return err
@@ -188,23 +27,9 @@ func readDirFn(dirName string, fn func(dirName, entName string, typ os.FileMode)
 			mode |= os.ModeDir
 		}
 
-		if err = fn(dirName, fi, mode); err != nil {
+		if err = fn(fi, mode); err != nil {
 			return err
 		}
 	}
 	return nil
 }
-
-func (w *walker) walk(root string, runUserCallback bool) error {
-	if runUserCallback {
-		err := w.fn(root, os.ModeDir)
-		if err == filepath.SkipDir || err == errSkipFile {
-			return nil
-		}
-		if err != nil {
-			return err
-		}
-	}
-
-	return readDirFn(root, w.onDirEnt)
-}

cmd/format-xl.go

@@ -828,7 +828,7 @@ func ecDrivesNoConfig(drivesPerSet int) int {
 // Make XL backend meta volumes.
 func makeFormatXLMetaVolumes(disk StorageAPI) error {
 	// Attempt to create MinIO internal buckets.
-	return disk.MakeVolBulk(minioMetaBucket, minioMetaTmpBucket, minioMetaMultipartBucket, minioMetaBackgroundOpsBucket)
+	return disk.MakeVolBulk(minioMetaBucket, minioMetaTmpBucket, minioMetaMultipartBucket, dataUsageBucket)
 }
 
 var initMetaVolIgnoredErrs = append(baseIgnoredErrs, errVolumeExists)

cmd/fs-v1-multipart.go

@@ -757,7 +757,7 @@ func (fs *FSObjects) AbortMultipartUpload(ctx context.Context, bucket, object, u
 // Removes multipart uploads if any older than `expiry` duration
 // on all buckets for every `cleanupInterval`, this function is
 // blocking and should be run in a go-routine.
-func (fs *FSObjects) cleanupStaleMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh chan struct{}) {
+func (fs *FSObjects) cleanupStaleMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh <-chan struct{}) {
 	ticker := time.NewTicker(cleanupInterval)
 	defer ticker.Stop()
 

cmd/fs-v1-multipart_test.go

@@ -21,6 +21,7 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"sync"
 	"testing"
 	"time"
 )
@@ -34,33 +35,38 @@ func TestFSCleanupMultipartUploadsInRoutine(t *testing.T) {
 	obj := initFSObjects(disk, t)
 	fs := obj.(*FSObjects)
 
-	// Close the go-routine, we are going to
-	// manually start it and test in this test case.
-	GlobalServiceDoneCh <- struct{}{}
-
 	bucketName := "bucket"
 	objectName := "object"
 
-	obj.MakeBucketWithLocation(context.Background(), bucketName, "")
+	// Create a context we can cancel.
-	uploadID, err := obj.NewMultipartUpload(context.Background(), bucketName, objectName, ObjectOptions{})
+	ctx, cancel := context.WithCancel(context.Background())
+	obj.MakeBucketWithLocation(ctx, bucketName, "")
+
+	uploadID, err := obj.NewMultipartUpload(ctx, bucketName, objectName, ObjectOptions{})
 	if err != nil {
 		t.Fatal("Unexpected err: ", err)
 	}
 
-	go fs.cleanupStaleMultipartUploads(context.Background(), 20*time.Millisecond, 0, GlobalServiceDoneCh)
+	var cleanupWg sync.WaitGroup
-
+	cleanupWg.Add(1)
-	// Wait for 40ms such that - we have given enough time for
+	go func() {
-	// cleanup routine to kick in.
+		defer cleanupWg.Done()
-	time.Sleep(40 * time.Millisecond)
+		fs.cleanupStaleMultipartUploads(context.Background(), time.Millisecond, 0, ctx.Done())
+	}()
 
-	// Close the routine we do not need it anymore.
+	// Wait for 100ms such that - we have given enough time for
-	GlobalServiceDoneCh <- struct{}{}
+	// cleanup routine to kick in. Flaky on slow systems...
+	time.Sleep(100 * time.Millisecond)
+	cancel()
+	cleanupWg.Wait()
 
 	// Check if upload id was already purged.
 	if err = obj.AbortMultipartUpload(context.Background(), bucketName, objectName, uploadID); err != nil {
 		if _, ok := err.(InvalidUploadID); !ok {
 			t.Fatal("Unexpected err: ", err)
 		}
+	} else {
+		t.Error("Item was not cleaned up.")
 	}
 }
 

cmd/fs-v1.go

@@ -37,12 +37,11 @@ import (
 	"github.com/minio/minio/cmd/config"
 	xhttp "github.com/minio/minio/cmd/http"
 	"github.com/minio/minio/cmd/logger"
-
 	bucketsse "github.com/minio/minio/pkg/bucket/encryption"
 	"github.com/minio/minio/pkg/bucket/lifecycle"
 	"github.com/minio/minio/pkg/bucket/object/tagging"
 	"github.com/minio/minio/pkg/bucket/policy"
-
+	"github.com/minio/minio/pkg/color"
 	"github.com/minio/minio/pkg/lock"
 	"github.com/minio/minio/pkg/madmin"
 	"github.com/minio/minio/pkg/mimedb"
@@ -112,7 +111,7 @@ func initMetaVolumeFS(fsPath, fsUUID string) error {
 		return err
 	}
 
-	if err := os.MkdirAll(pathJoin(fsPath, minioMetaBackgroundOpsBucket), 0777); err != nil {
+	if err := os.MkdirAll(pathJoin(fsPath, dataUsageBucket), 0777); err != nil {
 		return err
 	}
 
@@ -235,9 +234,26 @@ func (fs *FSObjects) waitForLowActiveIO() {
 }
 
 // CrawlAndGetDataUsage returns data usage stats of the current FS deployment
-func (fs *FSObjects) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan struct{}) DataUsageInfo {
+func (fs *FSObjects) CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error {
-	dataUsageInfo := updateUsage(fs.fsPath, endCh, fs.waitForLowActiveIO, func(item Item) (int64, error) {
+	// Load bucket totals
-		// Get file size, symlinks which cannot bex
+	var oldCache dataUsageCache
+	err := oldCache.load(ctx, fs, dataUsageCacheName)
+	if err != nil {
+		return err
+	}
+	if oldCache.Info.Name == "" {
+		oldCache.Info.Name = dataUsageRoot
+	}
+	if dataUsageDebug {
+		logger.Info(color.Green("FSObjects.CrawlAndGetDataUsage:") + " Start crawl cycle")
+	}
+	buckets, err := fs.ListBuckets(ctx)
+	if err != nil {
+		return err
+	}
+	t := time.Now()
+	cache, err := updateUsage(ctx, fs.fsPath, oldCache, fs.waitForLowActiveIO, func(item Item) (int64, error) {
+		// Get file size, symlinks which cannot be
 		// followed are automatically filtered by fastwalk.
 		fi, err := os.Stat(item.Path)
 		if err != nil {
@@ -245,11 +261,16 @@ func (fs *FSObjects) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan stru
 		}
 		return fi.Size(), nil
 	})
+	if dataUsageDebug {
+		logger.Info(color.Green("FSObjects.CrawlAndGetDataUsage:")+" Crawl time: %v", time.Since(t))
+	}
+	// Even if there was an error, the new cache may have better info.
+	if cache.Info.LastUpdate.After(oldCache.Info.LastUpdate) {
+		logger.LogIf(ctx, cache.save(ctx, fs, dataUsageCacheName))
+		updates <- cache.dui(dataUsageRoot, buckets)
+	}
 
-	dataUsageInfo.LastUpdate = UTCNow()
+	return err
-	atomic.StoreUint64(&fs.totalUsed, dataUsageInfo.ObjectsTotalSize)
-
-	return dataUsageInfo
 }
 
 /// Bucket operations

cmd/fs-v1_test.go

@@ -356,8 +356,6 @@ func TestFSListBuckets(t *testing.T) {
 		t.Fatal("Unexpected error: ", err)
 	}
 
-	GlobalServiceDoneCh <- struct{}{}
-
 	// Create a bucket with invalid name
 	if err := os.MkdirAll(pathJoin(fs.fsPath, "vo^"), 0777); err != nil {
 		t.Fatal("Unexpected error: ", err)

cmd/gateway-unsupported.go

@@ -50,9 +50,9 @@ func NewGatewayLayerWithLocker(gwLayer ObjectLayer) ObjectLayer {
 type GatewayUnsupported struct{}
 
 // CrawlAndGetDataUsage - crawl is not implemented for gateway
-func (a GatewayUnsupported) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan struct{}) DataUsageInfo {
+func (a GatewayUnsupported) CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error {
 	logger.CriticalIf(ctx, errors.New("not implemented"))
-	return DataUsageInfo{}
+	return NotImplemented{}
 }
 
 // NewNSLock is a dummy stub for gateway.

cmd/gateway/azure/gateway-azure.go

@@ -39,7 +39,6 @@ import (
 	humanize "github.com/dustin/go-humanize"
 	"github.com/minio/cli"
 	miniogopolicy "github.com/minio/minio-go/v6/pkg/policy"
-	"github.com/minio/minio/cmd"
 	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/bucket/policy"
@@ -1196,7 +1195,7 @@ func (a *azureObjects) CompleteMultipartUpload(ctx context.Context, bucket, obje
 	if err != nil {
 		return objInfo, azureToObjectError(err, bucket, object)
 	}
-	objMetadata["md5sum"] = cmd.ComputeCompleteMultipartMD5(uploadedParts)
+	objMetadata["md5sum"] = minio.ComputeCompleteMultipartMD5(uploadedParts)
 
 	_, err = objBlob.CommitBlockList(ctx, allBlocks, objProperties, objMetadata, azblob.BlobAccessConditions{})
 	if err != nil {

cmd/gateway/s3/gateway-s3-sse.go

@@ -679,7 +679,7 @@ func getGWContentPath(object string) string {
 }
 
 // Clean-up the stale incomplete encrypted multipart uploads. Should be run in a Go routine.
-func (l *s3EncObjects) cleanupStaleEncMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh chan struct{}) {
+func (l *s3EncObjects) cleanupStaleEncMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh <-chan struct{}) {
 	ticker := time.NewTicker(cleanupInterval)
 	defer ticker.Stop()
 

cmd/generic-handlers.go

@@ -353,7 +353,7 @@ func parseAmzDate(amzDateStr string) (amzDate time.Time, apiErr APIErrorCode) {
 // supported amz date formats.
 func parseAmzDateHeader(req *http.Request) (time.Time, APIErrorCode) {
 	for _, amzDateHeader := range amzDateHeaders {
-		amzDateStr := req.Header.Get(http.CanonicalHeaderKey(amzDateHeader))
+		amzDateStr := req.Header.Get(amzDateHeader)
 		if amzDateStr != "" {
 			return parseAmzDate(amzDateStr)
 		}

cmd/global-heal.go

@@ -39,7 +39,7 @@ var leaderLockTimeout = newDynamicTimeout(time.Minute, time.Minute)
 func newBgHealSequence(numDisks int) *healSequence {
 
 	reqInfo := &logger.ReqInfo{API: "BackgroundHeal"}
-	ctx := logger.SetReqInfo(context.Background(), reqInfo)
+	ctx := logger.SetReqInfo(GlobalContext, reqInfo)
 
 	hs := madmin.HealOpts{
 		// Remove objects that do not have read-quorum

cmd/http-stats.go

@@ -101,28 +101,24 @@ type HTTPAPIStats struct {
 
 // Inc increments the api stats counter.
 func (stats *HTTPAPIStats) Inc(api string) {
-	stats.Lock()
-	defer stats.Unlock()
 	if stats == nil {
 		return
 	}
+	stats.Lock()
+	defer stats.Unlock()
 	if stats.apiStats == nil {
 		stats.apiStats = make(map[string]int)
 	}
-	if _, ok := stats.apiStats[api]; ok {
+	stats.apiStats[api]++
-		stats.apiStats[api]++
-		return
-	}
-	stats.apiStats[api] = 1
 }
 
 // Dec increments the api stats counter.
 func (stats *HTTPAPIStats) Dec(api string) {
-	stats.Lock()
-	defer stats.Unlock()
 	if stats == nil {
 		return
 	}
+	stats.Lock()
+	defer stats.Unlock()
 	if val, ok := stats.apiStats[api]; ok && val > 0 {
 		stats.apiStats[api]--
 	}

cmd/iam-object-store.go

@@ -664,14 +664,15 @@ func listIAMConfigItems(objectAPI ObjectLayer, pathPrefix string, dirs bool,
 }
 
 func (iamOS *IAMObjectStore) watch(sys *IAMSys) {
+	ctx := GlobalContext
 	watchDisk := func() {
 		for {
 			select {
-			case <-GlobalServiceDoneCh:
+			case <-ctx.Done():
 				return
 			case <-time.NewTimer(globalRefreshIAMInterval).C:
 				err := iamOS.loadAll(sys, nil)
-				logger.LogIf(context.Background(), err)
+				logger.LogIf(ctx, err)
 			}
 		}
 	}

cmd/jwt/parser_test.go

@@ -27,7 +27,6 @@ import (
 	"time"
 
 	"github.com/dgrijalva/jwt-go"
-	jwtgo "github.com/dgrijalva/jwt-go"
 )
 
 var (
@@ -49,7 +48,7 @@ var jwtTestData = []struct {
 		"",
 		defaultKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 			},
 		},
@@ -61,7 +60,7 @@ var jwtTestData = []struct {
 		"", // autogen
 		defaultKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 				"exp": float64(time.Now().Unix() - 100),
 			},
@@ -74,7 +73,7 @@ var jwtTestData = []struct {
 		"", // autogen
 		defaultKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 				"nbf": float64(time.Now().Unix() + 100),
 			},
@@ -87,7 +86,7 @@ var jwtTestData = []struct {
 		"", // autogen
 		defaultKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 				"nbf": float64(time.Now().Unix() + 100),
 				"exp": float64(time.Now().Unix() - 100),
@@ -101,7 +100,7 @@ var jwtTestData = []struct {
 		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.EhkiHkoESI_cG3NPigFrxEk9Z60_oXrOT2vGm9Pn6RDgYNovYORQmmA0zs1AoAOf09ly2Nx2YAg6ABqAYga1AcMFkJljwxTT5fYphTuqpWdy4BELeSYJx5Ty2gmr8e7RonuUztrdD5WfPqLKMm1Ozp_T6zALpRmwTIW0QPnaBXaQD90FplAg46Iy1UlDKr-Eupy0i5SLch5Q-p2ZpaL_5fnTIUDlxC3pWhJTyx_71qDI-mAA_5lE_VdroOeflG56sSmDxopPEG3bFlSu1eowyBfxtu0_CuVd-M42RU75Zc4Gsj6uV77MBtbMrf4_7M_NUTSgoIF3fRqxrj0NzihIBg",
 		defaultKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 			},
 		},
@@ -113,7 +112,7 @@ var jwtTestData = []struct {
 		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.FhkiHkoESI_cG3NPigFrxEk9Z60_oXrOT2vGm9Pn6RDgYNovYORQmmA0zs1AoAOf09ly2Nx2YAg6ABqAYga1AcMFkJljwxTT5fYphTuqpWdy4BELeSYJx5Ty2gmr8e7RonuUztrdD5WfPqLKMm1Ozp_T6zALpRmwTIW0QPnaBXaQD90FplAg46Iy1UlDKr-Eupy0i5SLch5Q-p2ZpaL_5fnTIUDlxC3pWhJTyx_71qDI-mAA_5lE_VdroOeflG56sSmDxopPEG3bFlSu1eowyBfxtu0_CuVd-M42RU75Zc4Gsj6uV77MBtbMrf4_7M_NUTSgoIF3fRqxrj0NzihIBg",
 		nil,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 			},
 		},
@@ -125,7 +124,7 @@ var jwtTestData = []struct {
 		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.FhkiHkoESI_cG3NPigFrxEk9Z60_oXrOT2vGm9Pn6RDgYNovYORQmmA0zs1AoAOf09ly2Nx2YAg6ABqAYga1AcMFkJljwxTT5fYphTuqpWdy4BELeSYJx5Ty2gmr8e7RonuUztrdD5WfPqLKMm1Ozp_T6zALpRmwTIW0QPnaBXaQD90FplAg46Iy1UlDKr-Eupy0i5SLch5Q-p2ZpaL_5fnTIUDlxC3pWhJTyx_71qDI-mAA_5lE_VdroOeflG56sSmDxopPEG3bFlSu1eowyBfxtu0_CuVd-M42RU75Zc4Gsj6uV77MBtbMrf4_7M_NUTSgoIF3fRqxrj0NzihIBg",
 		emptyKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 			},
 		},
@@ -137,7 +136,7 @@ var jwtTestData = []struct {
 		"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJmb28iOiJiYXIifQ.FhkiHkoESI_cG3NPigFrxEk9Z60_oXrOT2vGm9Pn6RDgYNovYORQmmA0zs1AoAOf09ly2Nx2YAg6ABqAYga1AcMFkJljwxTT5fYphTuqpWdy4BELeSYJx5Ty2gmr8e7RonuUztrdD5WfPqLKMm1Ozp_T6zALpRmwTIW0QPnaBXaQD90FplAg46Iy1UlDKr-Eupy0i5SLch5Q-p2ZpaL_5fnTIUDlxC3pWhJTyx_71qDI-mAA_5lE_VdroOeflG56sSmDxopPEG3bFlSu1eowyBfxtu0_CuVd-M42RU75Zc4Gsj6uV77MBtbMrf4_7M_NUTSgoIF3fRqxrj0NzihIBg",
 		errorKeyFunc,
 		&MapClaims{
-			MapClaims: jwtgo.MapClaims{
+			MapClaims: jwt.MapClaims{
 				"foo": "bar",
 			},
 		},
@@ -149,7 +148,7 @@ var jwtTestData = []struct {
 		"",
 		defaultKeyFunc,
 		&StandardClaims{
-			StandardClaims: jwtgo.StandardClaims{
+			StandardClaims: jwt.StandardClaims{
 				ExpiresAt: time.Now().Add(time.Second * 10).Unix(),
 			},
 		},
@@ -160,7 +159,7 @@ var jwtTestData = []struct {
 
 func mapClaimsToken(claims *MapClaims) string {
 	claims.SetAccessKey("test")
-	j := jwtgo.NewWithClaims(jwtgo.SigningMethodHS512, claims)
+	j := jwt.NewWithClaims(jwt.SigningMethodHS512, claims)
 	tk, _ := j.SignedString([]byte("HelloSecret"))
 	return tk
 }
@@ -168,7 +167,7 @@ func mapClaimsToken(claims *MapClaims) string {
 func standardClaimsToken(claims *StandardClaims) string {
 	claims.AccessKey = "test"
 	claims.Subject = "test"
-	j := jwtgo.NewWithClaims(jwtgo.SigningMethodHS512, claims)
+	j := jwt.NewWithClaims(jwt.SigningMethodHS512, claims)
 	tk, _ := j.SignedString([]byte("HelloSecret"))
 	return tk
 }

cmd/logger/target/http/http.go

@@ -21,7 +21,6 @@ import (
 	"encoding/json"
 	"errors"
 	"net/http"
-	gohttp "net/http"
 	"strings"
 
 	xhttp "github.com/minio/minio/cmd/http"
@@ -41,7 +40,7 @@ type Target struct {
 	// User-Agent to be set on each log request sent to the `endpoint`
 	userAgent string
 	logKind   string
-	client    gohttp.Client
+	client    http.Client
 }
 
 func (h *Target) startHTTPLogger() {
@@ -54,7 +53,7 @@ func (h *Target) startHTTPLogger() {
 				continue
 			}
 
-			req, err := gohttp.NewRequest(http.MethodPost, h.endpoint, bytes.NewBuffer(logJSON))
+			req, err := http.NewRequest(http.MethodPost, h.endpoint, bytes.NewBuffer(logJSON))
 			if err != nil {
 				continue
 			}
@@ -78,12 +77,12 @@ func (h *Target) startHTTPLogger() {
 
 // New initializes a new logger target which
 // sends log over http to the specified endpoint
-func New(endpoint, userAgent, logKind string, transport *gohttp.Transport) *Target {
+func New(endpoint, userAgent, logKind string, transport *http.Transport) *Target {
 	h := Target{
 		endpoint:  endpoint,
 		userAgent: userAgent,
 		logKind:   strings.ToUpper(logKind),
-		client: gohttp.Client{
+		client: http.Client{
 			Transport: transport,
 		},
 		logCh: make(chan interface{}, 10000),

cmd/naughty-disk_test.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"io"
 	"sync"
 )
@@ -80,8 +81,8 @@ func (d *naughtyDisk) calcError() (err error) {
 func (d *naughtyDisk) SetDiskID(id string) {
 }
 
-func (d *naughtyDisk) CrawlAndGetDataUsage(endCh <-chan struct{}) (info DataUsageInfo, err error) {
+func (d *naughtyDisk) CrawlAndGetDataUsage(ctx context.Context, cache dataUsageCache) (info dataUsageCache, err error) {
-	return d.disk.CrawlAndGetDataUsage(endCh)
+	return d.disk.CrawlAndGetDataUsage(ctx, cache)
 }
 
 func (d *naughtyDisk) DiskInfo() (info DiskInfo, err error) {

cmd/object-api-datatypes.go

@@ -18,6 +18,7 @@ package cmd
 
 import (
 	"io"
+	"math"
 	"time"
 
 	"github.com/minio/minio/pkg/hash"
@@ -77,6 +78,11 @@ type objectHistogramInterval struct {
 	start, end int64
 }
 
+const (
+	// dataUsageBucketLen must be length of ObjectsHistogramIntervals
+	dataUsageBucketLen = 7
+)
+
 // ObjectsHistogramIntervals is the list of all intervals
 // of object sizes to be included in objects histogram.
 var ObjectsHistogramIntervals = []objectHistogramInterval{
@@ -86,20 +92,25 @@ var ObjectsHistogramIntervals = []objectHistogramInterval{
 	{"BETWEEN_10_MB_AND_64_MB", 1024 * 1024 * 10, 1024*1024*64 - 1},
 	{"BETWEEN_64_MB_AND_128_MB", 1024 * 1024 * 64, 1024*1024*128 - 1},
 	{"BETWEEN_128_MB_AND_512_MB", 1024 * 1024 * 128, 1024*1024*512 - 1},
-	{"GREATER_THAN_512_MB", 1024 * 1024 * 512, -1},
+	{"GREATER_THAN_512_MB", 1024 * 1024 * 512, math.MaxInt64},
 }
 
 // DataUsageInfo represents data usage stats of the underlying Object API
 type DataUsageInfo struct {
-	// The timestamp of when the data usage info is generated
+	// LastUpdate is the timestamp of when the data usage info was last updated.
+	// This does not indicate a full scan.
 	LastUpdate time.Time `json:"lastUpdate"`
 
 	ObjectsCount uint64 `json:"objectsCount"`
 	// Objects total size
-	ObjectsTotalSize      uint64            `json:"objectsTotalSize"`
+	ObjectsTotalSize uint64 `json:"objectsTotalSize"`
+
+	// ObjectsSizesHistogram contains information on objects across all buckets.
+	// See ObjectsHistogramIntervals.
 	ObjectsSizesHistogram map[string]uint64 `json:"objectsSizesHistogram"`
 
-	BucketsCount uint64            `json:"bucketsCount"`
+	BucketsCount uint64 `json:"bucketsCount"`
+	// BucketsSizes is "bucket name" -> size.
 	BucketsSizes map[string]uint64 `json:"bucketsSizes"`
 }
 

cmd/object-api-errors.go

@@ -274,7 +274,7 @@ func (e BucketSSEConfigNotFound) Error() string {
 // BucketNameInvalid - bucketname provided is invalid.
 type BucketNameInvalid GenericError
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e BucketNameInvalid) Error() string {
 	return "Bucket name invalid: " + e.Bucket
 }
@@ -290,17 +290,17 @@ type ObjectNameTooLong GenericError
 // ObjectNamePrefixAsSlash - object name has a slash as prefix.
 type ObjectNamePrefixAsSlash GenericError
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e ObjectNameInvalid) Error() string {
 	return "Object name invalid: " + e.Bucket + "#" + e.Object
 }
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e ObjectNameTooLong) Error() string {
 	return "Object name too long: " + e.Bucket + "#" + e.Object
 }
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e ObjectNamePrefixAsSlash) Error() string {
 	return "Object name contains forward slash as pefix: " + e.Bucket + "#" + e.Object
 }
@@ -308,7 +308,7 @@ func (e ObjectNamePrefixAsSlash) Error() string {
 // AllAccessDisabled All access to this object has been disabled
 type AllAccessDisabled GenericError
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e AllAccessDisabled) Error() string {
 	return "All access to this object has been disabled"
 }
@@ -316,7 +316,7 @@ func (e AllAccessDisabled) Error() string {
 // IncompleteBody You did not provide the number of bytes specified by the Content-Length HTTP header.
 type IncompleteBody GenericError
 
-// Return string an error formatted as the given text.
+// Error returns string an error formatted as the given text.
 func (e IncompleteBody) Error() string {
 	return e.Bucket + "#" + e.Object + "has incomplete body"
 }

cmd/object-api-interface.go

@@ -59,7 +59,7 @@ type ObjectLayer interface {
 
 	// Storage operations.
 	Shutdown(context.Context) error
-	CrawlAndGetDataUsage(context.Context, <-chan struct{}) DataUsageInfo
+	CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error
 	StorageInfo(ctx context.Context, local bool) StorageInfo // local queries only local disks
 
 	// Bucket operations.

cmd/object-api-utils.go

@@ -51,10 +51,6 @@ import (
 const (
 	// MinIO meta bucket.
 	minioMetaBucket = ".minio.sys"
-	// Background ops meta prefix
-	backgroundOpsMetaPrefix = "background-ops"
-	// MinIO Stats meta prefix.
-	minioMetaBackgroundOpsBucket = minioMetaBucket + SlashSeparator + backgroundOpsMetaPrefix
 	// Multipart meta prefix.
 	mpartMetaPrefix = "multipart"
 	// MinIO Multipart meta prefix.
@@ -77,7 +73,7 @@ func isMinioMetaBucketName(bucket string) bool {
 	return bucket == minioMetaBucket ||
 		bucket == minioMetaMultipartBucket ||
 		bucket == minioMetaTmpBucket ||
-		bucket == minioMetaBackgroundOpsBucket
+		bucket == dataUsageBucket
 }
 
 // IsValidBucketName verifies that a bucket name is in accordance with

cmd/object-handlers.go

@@ -1214,7 +1214,7 @@ func (api objectAPIHandlers) PutObjectHandler(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	if tags := r.Header.Get(http.CanonicalHeaderKey(xhttp.AmzObjectTagging)); tags != "" {
+	if tags := r.Header.Get(xhttp.AmzObjectTagging); tags != "" {
 		metadata[xhttp.AmzObjectTagging], err = extractTags(ctx, tags)
 		if err != nil {
 			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))

cmd/posix-diskid-check.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"io"
 )
 
@@ -38,8 +39,8 @@ func (p *posixDiskIDCheck) IsOnline() bool {
 	return storedDiskID == p.diskID
 }
 
-func (p *posixDiskIDCheck) CrawlAndGetDataUsage(endCh <-chan struct{}) (DataUsageInfo, error) {
+func (p *posixDiskIDCheck) CrawlAndGetDataUsage(ctx context.Context, cache dataUsageCache) (dataUsageCache, error) {
-	return p.storage.CrawlAndGetDataUsage(endCh)
+	return p.storage.CrawlAndGetDataUsage(ctx, cache)
 }
 
 func (p *posixDiskIDCheck) Hostname() string {

cmd/posix.go

@@ -338,8 +338,8 @@ func (s *posix) waitForLowActiveIO() {
 	}
 }
 
-func (s *posix) CrawlAndGetDataUsage(endCh <-chan struct{}) (DataUsageInfo, error) {
+func (s *posix) CrawlAndGetDataUsage(ctx context.Context, cache dataUsageCache) (dataUsageCache, error) {
-	dataUsageInfo := updateUsage(s.diskPath, endCh, s.waitForLowActiveIO, func(item Item) (int64, error) {
+	dataUsageInfo, err := updateUsage(ctx, s.diskPath, cache, s.waitForLowActiveIO, func(item Item) (int64, error) {
 		// Look for `xl.json' at the leaf.
 		if !strings.HasSuffix(item.Path, SlashSeparator+xlMetaJSONFile) {
 			// if no xl.json found, skip the file.
@@ -353,14 +353,20 @@ func (s *posix) CrawlAndGetDataUsage(endCh <-chan struct{}) (DataUsageInfo, erro
 
 		meta, err := xlMetaV1UnmarshalJSON(context.Background(), xlMetaBuf)
 		if err != nil {
-			return 0, errSkipFile
+			return 0, nil
 		}
 
 		return meta.Stat.Size, nil
 	})
-
+	if err != nil {
-	dataUsageInfo.LastUpdate = UTCNow()
+		return dataUsageInfo, err
-	atomic.StoreUint64(&s.totalUsed, dataUsageInfo.ObjectsTotalSize)
+	}
+	dataUsageInfo.Info.LastUpdate = time.Now()
+	total := dataUsageInfo.sizeRecursive(dataUsageInfo.Info.Name)
+	if total == nil {
+		total = &dataUsageEntry{}
+	}
+	atomic.StoreUint64(&s.totalUsed, uint64(total.Size))
 	return dataUsageInfo, nil
 }
 

cmd/server-main.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
 	"os"
 	"os/signal"
@@ -361,6 +362,9 @@ func serverMain(ctx *cli.Context) {
 	}
 
 	httpServer := xhttp.NewServer([]string{globalMinioAddr}, criticalErrorHandler{handler}, getCert)
+	httpServer.BaseContext = func(listener net.Listener) context.Context {
+		return GlobalContext
+	}
 	go func() {
 		globalHTTPServerErrorCh <- httpServer.Start()
 	}()

cmd/server-startup-msg.go

@@ -92,13 +92,13 @@ func printStartupSafeModeMessage(apiEndpoints []string, err error) {
 			mcMessage := fmt.Sprintf("> mc.exe config host add %s %s %s %s --api s3v4", alias,
 				endPoint, cred.AccessKey, cred.SecretKey)
 			logStartupMessage(fmt.Sprintf(getFormatStr(len(mcMessage), 3), mcMessage))
-			mcMessage = fmt.Sprintf("> mc.exe admin config --help")
+			mcMessage = "> mc.exe admin config --help"
 			logStartupMessage(fmt.Sprintf(getFormatStr(len(mcMessage), 3), mcMessage))
 		} else {
 			mcMessage := fmt.Sprintf("$ mc config host add %s %s %s %s --api s3v4", alias,
 				endPoint, cred.AccessKey, cred.SecretKey)
 			logStartupMessage(fmt.Sprintf(getFormatStr(len(mcMessage), 3), mcMessage))
-			mcMessage = fmt.Sprintf("$ mc admin config --help")
+			mcMessage = "$ mc admin config --help"
 			logStartupMessage(fmt.Sprintf(getFormatStr(len(mcMessage), 3), mcMessage))
 		}
 	}

cmd/service.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"os"
 	"os/exec"
 	"syscall"
@@ -35,11 +36,22 @@ const (
 var globalServiceSignalCh chan serviceSignal
 
 // GlobalServiceDoneCh - Global service done channel.
-var GlobalServiceDoneCh chan struct{}
+var GlobalServiceDoneCh <-chan struct{}
+
+// GlobalContext context that is canceled when server is requested to shut down.
+var GlobalContext context.Context
+
+// cancelGlobalContext can be used to indicate server shutdown.
+var cancelGlobalContext context.CancelFunc
 
 // Initialize service mutex once.
 func init() {
-	GlobalServiceDoneCh = make(chan struct{})
+	initGlobalContext()
+}
+
+func initGlobalContext() {
+	GlobalContext, cancelGlobalContext = context.WithCancel(context.Background())
+	GlobalServiceDoneCh = GlobalContext.Done()
 	globalServiceSignalCh = make(chan serviceSignal)
 }
 

cmd/signals.go

@@ -57,7 +57,7 @@ func handleSignals() {
 		}
 
 		// send signal to various go-routines that they need to quit.
-		close(GlobalServiceDoneCh)
+		cancelGlobalContext()
 
 		if objAPI := newObjectLayerWithoutSafeModeFn(); objAPI != nil {
 			oerr = objAPI.Shutdown(context.Background())

cmd/storage-interface.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"io"
 )
 
@@ -32,7 +33,7 @@ type StorageAPI interface {
 	SetDiskID(id string)
 
 	DiskInfo() (info DiskInfo, err error)
-	CrawlAndGetDataUsage(endCh <-chan struct{}) (DataUsageInfo, error)
+	CrawlAndGetDataUsage(ctx context.Context, cache dataUsageCache) (dataUsageCache, error)
 
 	// Volume operations.
 	MakeVol(volume string) (err error)

cmd/storage-rest-client.go

@@ -17,7 +17,6 @@
 package cmd
 
 import (
-	"bufio"
 	"bytes"
 	"context"
 	"crypto/tls"
@@ -152,26 +151,25 @@ func (client *storageRESTClient) Hostname() string {
 	return client.endpoint.Host
 }
 
-func (client *storageRESTClient) CrawlAndGetDataUsage(endCh <-chan struct{}) (DataUsageInfo, error) {
+func (client *storageRESTClient) CrawlAndGetDataUsage(ctx context.Context, cache dataUsageCache) (dataUsageCache, error) {
-	respBody, err := client.call(storageRESTMethodCrawlAndGetDataUsage, nil, nil, -1)
+	b := cache.serialize()
+	respBody, err := client.call(storageRESTMethodCrawlAndGetDataUsage,
+		url.Values{},
+		bytes.NewBuffer(b), int64(len(b)))
 	defer http.DrainBody(respBody)
 	if err != nil {
-		return DataUsageInfo{}, err
+		return cache, err
 	}
-	reader := bufio.NewReader(respBody)
+	reader, err := waitForHTTPResponse(respBody)
-	for {
+	if err != nil {
-		b, err := reader.ReadByte()
+		return cache, err
-		if err != nil {
+	}
-			return DataUsageInfo{}, err
+	b, err = ioutil.ReadAll(reader)
-		}
+	if err != nil {
-		if b != ' ' {
+		return cache, err
-			reader.UnreadByte()
-			break
-		}
 	}
-	var usageInfo DataUsageInfo
+	var newCache dataUsageCache
-	err = gob.NewDecoder(reader).Decode(&usageInfo)
+	return newCache, newCache.deserialize(b)
-	return usageInfo, err
 }
 
 func (client *storageRESTClient) SetDiskID(id string) {
@@ -418,7 +416,7 @@ func (client *storageRESTClient) DeleteFileBulk(volume string, paths []string) (
 		return nil, err
 	}
 
-	reader, err := clearLeadingSpaces(respBody)
+	reader, err := waitForHTTPResponse(respBody)
 	if err != nil {
 		return nil, err
 	}
@@ -455,7 +453,7 @@ func (client *storageRESTClient) DeletePrefixes(volume string, paths []string) (
 		return nil, err
 	}
 
-	reader, err := clearLeadingSpaces(respBody)
+	reader, err := waitForHTTPResponse(respBody)
 	if err != nil {
 		return nil, err
 	}
@@ -484,22 +482,6 @@ func (client *storageRESTClient) RenameFile(srcVolume, srcPath, dstVolume, dstPa
 	return err
 }
 
-// clearLeadingSpaces removes all the first spaces returned from a reader.
-func clearLeadingSpaces(r io.Reader) (io.Reader, error) {
-	reader := bufio.NewReader(r)
-	for {
-		b, err := reader.ReadByte()
-		if err != nil {
-			return nil, err
-		}
-		if b != ' ' {
-			reader.UnreadByte()
-			break
-		}
-	}
-	return reader, nil
-}
-
 func (client *storageRESTClient) VerifyFile(volume, path string, size int64, algo BitrotAlgorithm, sum []byte, shardSize int64) error {
 	values := make(url.Values)
 	values.Set(storageRESTVolume, volume)
@@ -514,7 +496,7 @@ func (client *storageRESTClient) VerifyFile(volume, path string, size int64, alg
 	if err != nil {
 		return err
 	}
-	reader, err := clearLeadingSpaces(respBody)
+	reader, err := waitForHTTPResponse(respBody)
 	if err != nil {
 		return err
 	}

cmd/storage-rest-common.go

@@ -17,7 +17,7 @@
 package cmd
 
 const (
-	storageRESTVersion       = "v15" // Adding DeletePrefixes API
+	storageRESTVersion       = "v16" // CrawlAndGetDataUsageHandler API change
 	storageRESTVersionPrefix = SlashSeparator + storageRESTVersion
 	storageRESTPrefix        = minioReservedBucketPath + "/storage"
 )

cmd/storage-rest-server.go

@@ -24,6 +24,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"os/user"
 	"path"
@@ -138,16 +139,28 @@ func (s *storageRESTServer) CrawlAndGetDataUsageHandler(w http.ResponseWriter, r
 	}
 
 	w.Header().Set(xhttp.ContentType, "text/event-stream")
-	doneCh := sendWhiteSpaceToHTTPResponse(w)
+	b, err := ioutil.ReadAll(r.Body)
-	usageInfo, err := s.storage.CrawlAndGetDataUsage(GlobalServiceDoneCh)
+	if err != nil {
-	<-doneCh
+		s.writeErrorResponse(w, err)
-
+		return
+	}
+	var cache dataUsageCache
+	err = cache.deserialize(b)
 	if err != nil {
+		logger.LogIf(r.Context(), err)
 		s.writeErrorResponse(w, err)
 		return
 	}
 
-	gob.NewEncoder(w).Encode(usageInfo)
+	done := keepHTTPResponseAlive(w)
+	usageInfo, err := s.storage.CrawlAndGetDataUsage(r.Context(), cache)
+	done()
+
+	if err != nil {
+		s.writeErrorResponse(w, err)
+		return
+	}
+	w.Write(usageInfo.serialize())
 	w.(http.Flusher).Flush()
 }
 
@@ -510,9 +523,9 @@ func (s *storageRESTServer) DeleteFileBulkHandler(w http.ResponseWriter, r *http
 
 	w.Header().Set(xhttp.ContentType, "text/event-stream")
 	encoder := gob.NewEncoder(w)
-	doneCh := sendWhiteSpaceToHTTPResponse(w)
+	done := keepHTTPResponseAlive(w)
 	errs, err := s.storage.DeleteFileBulk(volume, filePaths)
-	<-doneCh
+	done()
 	if err != nil {
 		s.writeErrorResponse(w, err)
 		return
@@ -556,9 +569,9 @@ func (s *storageRESTServer) DeletePrefixesHandler(w http.ResponseWriter, r *http
 
 	w.Header().Set(xhttp.ContentType, "text/event-stream")
 	encoder := gob.NewEncoder(w)
-	doneCh := sendWhiteSpaceToHTTPResponse(w)
+	done := keepHTTPResponseAlive(w)
 	errs, err := s.storage.DeletePrefixes(volume, prefixes)
-	<-doneCh
+	done()
 	if err != nil {
 		s.writeErrorResponse(w, err)
 		return
@@ -590,11 +603,15 @@ func (s *storageRESTServer) RenameFileHandler(w http.ResponseWriter, r *http.Req
 	}
 }
 
-// Send whitespace to the client to avoid timeouts with long storage
+// keepHTTPResponseAlive can be used to avoid timeouts with long storage
 // operations, such as bitrot verification or data usage crawling.
-func sendWhiteSpaceToHTTPResponse(w http.ResponseWriter) <-chan struct{} {
+// Every 10 seconds a space character is sent.
+// The returned function should always be called to release resources.
+// waitForHTTPResponse should be used to the receiving side.
+func keepHTTPResponseAlive(w http.ResponseWriter) func() {
 	doneCh := make(chan struct{})
 	go func() {
+		defer close(doneCh)
 		ticker := time.NewTicker(time.Second * 10)
 		for {
 			select {
@@ -602,13 +619,38 @@ func sendWhiteSpaceToHTTPResponse(w http.ResponseWriter) <-chan struct{} {
 				w.Write([]byte(" "))
 				w.(http.Flusher).Flush()
 			case doneCh <- struct{}{}:
+				w.Write([]byte{0})
 				ticker.Stop()
 				return
 			}
 		}
-
 	}()
-	return doneCh
+	return func() {
+		// Indicate we are ready to write.
+		<-doneCh
+		// Wait for channel to be closed so we don't race on writes.
+		<-doneCh
+	}
+}
+
+// waitForHTTPResponse will wait for responses where keepHTTPResponseAlive
+// has been used.
+// The returned reader contains the payload.
+func waitForHTTPResponse(respBody io.Reader) (io.Reader, error) {
+	reader := bufio.NewReader(respBody)
+	for {
+		b, err := reader.ReadByte()
+		if err != nil {
+			return nil, err
+		}
+		if b != ' ' {
+			if b != 0 {
+				reader.UnreadByte()
+			}
+			break
+		}
+	}
+	return reader, nil
 }
 
 // VerifyFileResp - VerifyFile()'s response.
@@ -650,9 +692,9 @@ func (s *storageRESTServer) VerifyFile(w http.ResponseWriter, r *http.Request) {
 	}
 	w.Header().Set(xhttp.ContentType, "text/event-stream")
 	encoder := gob.NewEncoder(w)
-	doneCh := sendWhiteSpaceToHTTPResponse(w)
+	done := keepHTTPResponseAlive(w)
 	err = s.storage.VerifyFile(volume, filePath, size, BitrotAlgorithmFromString(algoStr), hash, int64(shardSize))
-	<-doneCh
+	done()
 	vresp := &VerifyFileResp{}
 	if err != nil {
 		vresp.Err = StorageErr(err.Error())

cmd/streaming-signature-v4.go

@@ -102,7 +102,7 @@ func calculateSeedSignature(r *http.Request) (cred auth.Credentials, signature s
 
 	// Extract date, if not present throw error.
 	var dateStr string
-	if dateStr = req.Header.Get(http.CanonicalHeaderKey("x-amz-date")); dateStr == "" {
+	if dateStr = req.Header.Get("x-amz-date"); dateStr == "" {
 		if dateStr = r.Header.Get("Date"); dateStr == "" {
 			return cred, "", "", time.Time{}, ErrMissingDateHeader
 		}

cmd/test-utils_test.go

@@ -419,22 +419,6 @@ func resetGlobalConfigPath() {
 	globalConfigDir = &ConfigDir{path: ""}
 }
 
-func resetGlobalServiceDoneCh() {
-	// Repeatedly send on the service done channel, so that
-	// listening go-routines will quit. This works better than
-	// closing the channel - closing introduces a new race, as the
-	// current thread writes to the variable, and other threads
-	// listening on it, read from it.
-loop:
-	for {
-		select {
-		case GlobalServiceDoneCh <- struct{}{}:
-		default:
-			break loop
-		}
-	}
-}
-
 // sets globalObjectAPI to `nil`.
 func resetGlobalObjectAPI() {
 	globalObjLayerMutex.Lock()
@@ -499,7 +483,8 @@ func resetGlobalIAMSys() {
 func resetTestGlobals() {
 	// close any indefinitely running go-routines from previous
 	// tests.
-	resetGlobalServiceDoneCh()
+	cancelGlobalContext()
+	initGlobalContext()
 	// set globalObjectAPI to `nil`.
 	resetGlobalObjectAPI()
 	// Reset config path set.

cmd/web-handlers_test.go

@@ -449,7 +449,7 @@ func testListBucketsWebHandler(obj ObjectLayer, instanceType string, t TestErrHa
 		t.Fatalf("Cannot find the bucket already created by MakeBucket")
 	}
 	if listBucketsReply.Buckets[0].Name != bucketName {
-		t.Fatalf("Found another bucket other than already created by MakeBucket")
+		t.Fatalf("Found another bucket %q other than already created by MakeBucket", listBucketsReply.Buckets[0].Name)
 	}
 }
 

cmd/xl-sets.go

@@ -235,7 +235,7 @@ func (s *xlSets) connectDisks() {
 // monitorAndConnectEndpoints this is a monitoring loop to keep track of disconnected
 // endpoints by reconnecting them and making sure to place them into right position in
 // the set topology, this monitoring happens at a given monitoring interval.
-func (s *xlSets) monitorAndConnectEndpoints(monitorInterval time.Duration) {
+func (s *xlSets) monitorAndConnectEndpoints(ctx context.Context, monitorInterval time.Duration) {
 
 	ticker := time.NewTicker(monitorInterval)
 	// Stop the timer.
@@ -243,7 +243,7 @@ func (s *xlSets) monitorAndConnectEndpoints(monitorInterval time.Duration) {
 
 	for {
 		select {
-		case <-GlobalServiceDoneCh:
+		case <-ctx.Done():
 			return
 		case <-s.disksConnectDoneCh:
 			return
@@ -332,7 +332,7 @@ func newXLSets(endpoints Endpoints, format *formatXLV3, setCount int, drivesPerS
 	s.connectDisksWithQuorum()
 
 	// Start the disk monitoring and connect routine.
-	go s.monitorAndConnectEndpoints(defaultMonitorConnectEndpointInterval)
+	go s.monitorAndConnectEndpoints(GlobalContext, defaultMonitorConnectEndpointInterval)
 
 	go s.maintainMRFList()
 	go s.healMRFRoutine()
@@ -445,8 +445,8 @@ func (s *xlSets) StorageInfo(ctx context.Context, local bool) StorageInfo {
 	return storageInfo
 }
 
-func (s *xlSets) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan struct{}) DataUsageInfo {
+func (s *xlSets) CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error {
-	return DataUsageInfo{}
+	return NotImplemented{}
 }
 
 // Shutdown shutsdown all erasure coded sets in parallel
@@ -1327,7 +1327,7 @@ func (s *xlSets) ReloadFormat(ctx context.Context, dryRun bool) (err error) {
 	s.connectDisks()
 
 	// Restart monitoring loop to monitor reformatted disks again.
-	go s.monitorAndConnectEndpoints(defaultMonitorConnectEndpointInterval)
+	go s.monitorAndConnectEndpoints(GlobalContext, defaultMonitorConnectEndpointInterval)
 
 	return nil
 }
@@ -1516,7 +1516,7 @@ func (s *xlSets) HealFormat(ctx context.Context, dryRun bool) (res madmin.HealRe
 		s.connectDisks()
 
 		// Restart our monitoring loop to start monitoring newly formatted disks.
-		go s.monitorAndConnectEndpoints(defaultMonitorConnectEndpointInterval)
+		go s.monitorAndConnectEndpoints(GlobalContext, defaultMonitorConnectEndpointInterval)
 	}
 
 	return res, nil
@@ -1764,6 +1764,10 @@ func (s *xlSets) healMRFRoutine() {
 	// Wait until background heal state is initialized
 	var bgSeq *healSequence
 	for {
+		if globalBackgroundHealState == nil {
+			time.Sleep(time.Second)
+			continue
+		}
 		var ok bool
 		bgSeq, ok = globalBackgroundHealState.getHealSequenceByToken(bgHealingUUID)
 		if ok {

cmd/xl-v1-multipart.go

@@ -765,7 +765,7 @@ func (xl xlObjects) AbortMultipartUpload(ctx context.Context, bucket, object, up
 }
 
 // Clean-up the old multipart uploads. Should be run in a Go routine.
-func (xl xlObjects) cleanupStaleMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh chan struct{}) {
+func (xl xlObjects) cleanupStaleMultipartUploads(ctx context.Context, cleanupInterval, expiry time.Duration, doneCh <-chan struct{}) {
 	ticker := time.NewTicker(cleanupInterval)
 	defer ticker.Stop()
 

cmd/xl-v1-multipart_test.go

@@ -18,6 +18,7 @@ package cmd
 
 import (
 	"context"
+	"sync"
 	"testing"
 	"time"
 )
@@ -35,10 +36,6 @@ func TestXLCleanupStaleMultipartUploads(t *testing.T) {
 	z := obj.(*xlZones)
 	xl := z.zones[0].sets[0]
 
-	// Close the go-routine, we are going to
-	// manually start it and test in this test case.
-	GlobalServiceDoneCh <- struct{}{}
-
 	bucketName := "bucket"
 	objectName := "object"
 	var opts ObjectOptions
@@ -49,19 +46,30 @@ func TestXLCleanupStaleMultipartUploads(t *testing.T) {
 		t.Fatal("Unexpected err: ", err)
 	}
 
-	go xl.cleanupStaleMultipartUploads(context.Background(), 20*time.Millisecond, 0, GlobalServiceDoneCh)
+	// Create a context we can cancel.
+	ctx, cancel := context.WithCancel(context.Background())
+
+	var cleanupWg sync.WaitGroup
+	cleanupWg.Add(1)
+	go func() {
+		defer cleanupWg.Done()
+		xl.cleanupStaleMultipartUploads(context.Background(), time.Millisecond, 0, ctx.Done())
+	}()
 
-	// Wait for 40ms such that - we have given enough time for
+	// Wait for 100ms such that - we have given enough time for cleanup routine to kick in.
-	// cleanup routine to kick in.
+	// Flaky on slow systems :/
-	time.Sleep(40 * time.Millisecond)
+	time.Sleep(100 * time.Millisecond)
 
-	// Close the routine we do not need it anymore.
+	// Exit cleanup..
-	GlobalServiceDoneCh <- struct{}{}
+	cancel()
+	cleanupWg.Wait()
 
 	// Check if upload id was already purged.
 	if err = obj.AbortMultipartUpload(context.Background(), bucketName, objectName, uploadID); err != nil {
 		if _, ok := err.(InvalidUploadID); !ok {
 			t.Fatal("Unexpected err: ", err)
 		}
+	} else {
+		t.Error("Item was not cleaned up.")
 	}
 }

cmd/xl-v1.go

@@ -18,11 +18,15 @@ package cmd
 
 import (
 	"context"
+	"fmt"
+	"path"
 	"sort"
 	"sync"
+	"time"
 
 	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/bpool"
+	"github.com/minio/minio/pkg/color"
 	"github.com/minio/minio/pkg/dsync"
 	"github.com/minio/minio/pkg/madmin"
 	"github.com/minio/minio/pkg/sync/errgroup"
@@ -195,45 +199,177 @@ func (xl xlObjects) GetMetrics(ctx context.Context) (*Metrics, error) {
 	return &Metrics{}, NotImplemented{}
 }
 
-// CrawlAndGetDataUsage picks three random disks to crawl and get data usage
+// CrawlAndGetDataUsage will start crawling buckets and send updated totals as they are traversed.
-func (xl xlObjects) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan struct{}) DataUsageInfo {
+// Updates are sent on a regular basis and the caller *must* consume them.
-	var randomDisks []StorageAPI
+func (xl xlObjects) CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error {
+	cache := make(chan dataUsageCache, 1)
+	defer close(cache)
+	buckets, err := xl.ListBuckets(ctx)
+	if err != nil {
+		return err
+	}
+	go func() {
+		for update := range cache {
+			updates <- update.dui(update.Info.Name, buckets)
+		}
+	}()
+	return xl.crawlAndGetDataUsage(ctx, buckets, cache)
+}
+
+// CrawlAndGetDataUsage will start crawling buckets and send updated totals as they are traversed.
+// Updates are sent on a regular basis and the caller *must* consume them.
+func (xl xlObjects) crawlAndGetDataUsage(ctx context.Context, buckets []BucketInfo, updates chan<- dataUsageCache) error {
+	var disks []StorageAPI
+
 	for _, d := range xl.getLoadBalancedDisks() {
 		if d == nil || !d.IsOnline() {
 			continue
 		}
-		randomDisks = append(randomDisks, d)
+		disks = append(disks, d)
-		if len(randomDisks) >= 3 {
+	}
-			break
+	if len(disks) == 0 || len(buckets) == 0 {
-		}
+		return nil
+	}
+
+	// Load bucket totals
+	oldCache := dataUsageCache{}
+	err := oldCache.load(ctx, xl, dataUsageCacheName)
+	if err != nil {
+		return err
 	}
 
-	var dataUsageResults = make([]DataUsageInfo, len(randomDisks))
+	// New cache..
+	cache := dataUsageCache{
+		Info: dataUsageCacheInfo{
+			Name:      dataUsageRoot,
+			NextCycle: oldCache.Info.NextCycle,
+		},
+		Cache: make(map[dataUsageHash]dataUsageEntry, len(oldCache.Cache)),
+	}
 
+	// Put all buckets into channel.
+	bucketCh := make(chan BucketInfo, len(buckets))
+	// Add new buckets first
+	for _, b := range buckets {
+		if oldCache.find(b.Name) == nil {
+			bucketCh <- b
+		}
+	}
+	// Add existing buckets.
+	for _, b := range buckets {
+		e := oldCache.find(b.Name)
+		if e != nil {
+			bucketCh <- b
+			cache.replace(b.Name, dataUsageRoot, *e)
+		}
+	}
+
+	close(bucketCh)
+	buckets = nil
+	bucketResults := make(chan dataUsageEntryInfo, len(disks))
+
+	// Start async collector/saver.
+	// This goroutine owns the cache.
+	var saverWg sync.WaitGroup
+	saverWg.Add(1)
+	go func() {
+		const updateTime = 30 * time.Second
+		t := time.NewTicker(updateTime)
+		defer t.Stop()
+		defer saverWg.Done()
+		var lastSave time.Time
+
+	saveLoop:
+		for {
+			select {
+			case <-ctx.Done():
+				// Return without saving.
+				return
+			case <-t.C:
+				if cache.Info.LastUpdate.Equal(lastSave) {
+					continue
+				}
+				logger.LogIf(ctx, cache.save(ctx, xl, dataUsageCacheName))
+				updates <- cache.clone()
+				lastSave = cache.Info.LastUpdate
+			case v, ok := <-bucketResults:
+				if !ok {
+					break saveLoop
+				}
+				cache.replace(v.Name, v.Parent, v.Entry)
+				cache.Info.LastUpdate = time.Now()
+			}
+		}
+		// Save final state...
+		cache.Info.NextCycle++
+		cache.Info.LastUpdate = time.Now()
+		logger.LogIf(ctx, cache.save(ctx, xl, dataUsageCacheName))
+		updates <- cache
+	}()
+
+	// Start one crawler per disk
 	var wg sync.WaitGroup
-	for i := 0; i < len(randomDisks); i++ {
+	wg.Add(len(disks))
-		wg.Add(1)
+	for i := range disks {
-		go func(index int, disk StorageAPI) {
+		go func(i int) {
 			defer wg.Done()
-			var err error
+			disk := disks[i]
-			dataUsageResults[index], err = disk.CrawlAndGetDataUsage(endCh)
+
-			if err != nil {
+			for bucket := range bucketCh {
-				logger.LogIf(ctx, err)
+				select {
+				case <-ctx.Done():
+					return
+				default:
+				}
+				if dataUsageDebug {
+					logger.Info(color.Green("crawlAndGetDataUsage:")+" Scanning bucket %v.", bucket.Name)
+				}
+				// Load cache for bucket
+				cacheName := path.Join(dataUsageBucketCacheDir, bucket.Name+".bin")
+				cache := dataUsageCache{}
+				logger.LogIf(ctx, cache.load(ctx, xl, cacheName))
+				if cache.Info.Name == "" {
+					cache.Info.Name = bucket.Name
+				}
+				if cache.Info.Name != bucket.Name {
+					logger.LogIf(ctx, fmt.Errorf("cache name mismatch: %s != %s", cache.Info.Name, bucket.Name))
+					cache.Info = dataUsageCacheInfo{
+						Name:       bucket.Name,
+						LastUpdate: time.Time{},
+						NextCycle:  0,
+					}
+				}
+
+				// Calc usage
+				before := cache.Info.LastUpdate
+				cache, err = disk.CrawlAndGetDataUsage(ctx, cache)
+				if err != nil {
+					logger.LogIf(ctx, err)
+					if cache.Info.LastUpdate.After(before) {
+						logger.LogIf(ctx, cache.save(ctx, xl, cacheName))
+					}
+					continue
+				}
+
+				var root dataUsageEntry
+				if r := cache.root(); r != nil {
+					root = cache.flatten(*r)
+				}
+				bucketResults <- dataUsageEntryInfo{
+					Name:   cache.Info.Name,
+					Parent: dataUsageRoot,
+					Entry:  root,
+				}
+				// Save cache
+				logger.LogIf(ctx, cache.save(ctx, xl, cacheName))
 			}
-		}(i, randomDisks[i])
+		}(i)
 	}
 	wg.Wait()
+	close(bucketResults)
+	saverWg.Wait()
 
-	var dataUsageInfo = dataUsageResults[0]
+	return nil
-	// Pick the crawling result of the disk which has the most
-	// number of objects in it.
-	for i := 1; i < len(dataUsageResults); i++ {
-		if dataUsageResults[i].ObjectsCount > dataUsageInfo.ObjectsCount {
-			dataUsageInfo = dataUsageResults[i]
-		}
-	}
-
-	return dataUsageInfo
 }
 
 // IsReady - No Op.

cmd/xl-zones.go

@@ -24,6 +24,7 @@ import (
 	"net/http"
 	"strings"
 	"sync"
+	"time"
 
 	xhttp "github.com/minio/minio/cmd/http"
 	"github.com/minio/minio/cmd/logger"
@@ -31,6 +32,7 @@ import (
 	"github.com/minio/minio/pkg/bucket/lifecycle"
 	"github.com/minio/minio/pkg/bucket/object/tagging"
 	"github.com/minio/minio/pkg/bucket/policy"
+	"github.com/minio/minio/pkg/color"
 	"github.com/minio/minio/pkg/madmin"
 	"github.com/minio/minio/pkg/sync/errgroup"
 )
@@ -215,44 +217,111 @@ func (z *xlZones) StorageInfo(ctx context.Context, local bool) StorageInfo {
 	return storageInfo
 }
 
-func (z *xlZones) CrawlAndGetDataUsage(ctx context.Context, endCh <-chan struct{}) DataUsageInfo {
+func (z *xlZones) CrawlAndGetDataUsage(ctx context.Context, updates chan<- DataUsageInfo) error {
-	var aggDataUsageInfo = struct {
+	ctx, cancel := context.WithCancel(ctx)
-		sync.Mutex
+	defer cancel()
-		DataUsageInfo
-	}{}
-
-	aggDataUsageInfo.ObjectsSizesHistogram = make(map[string]uint64)
-	aggDataUsageInfo.BucketsSizes = make(map[string]uint64)
-
 	var wg sync.WaitGroup
+	var mu sync.Mutex
+	var results []dataUsageCache
+	var firstErr error
+	var knownBuckets = make(map[string]struct{}) // used to deduplicate buckets.
+	var allBuckets []BucketInfo
+
+	t := time.Now()
+	if dataUsageDebug {
+		logger.Info(color.Green("xlZones.CrawlAndGetDataUsage:") + " Start crawl cycle")
+	}
+	// Collect for each set in zones.
 	for _, z := range z.zones {
 		for _, xlObj := range z.sets {
-			wg.Add(1)
+			// Add new buckets.
-			go func(xl *xlObjects) {
+			buckets, err := xlObj.ListBuckets(ctx)
-				defer wg.Done()
+			if err != nil {
-				info := xl.CrawlAndGetDataUsage(ctx, endCh)
+				return err
-
+			}
-				aggDataUsageInfo.Lock()
+			for _, b := range buckets {
-				aggDataUsageInfo.ObjectsCount += info.ObjectsCount
+				if _, ok := knownBuckets[b.Name]; ok {
-				aggDataUsageInfo.ObjectsTotalSize += info.ObjectsTotalSize
+					continue
-				if aggDataUsageInfo.BucketsCount < info.BucketsCount {
-					aggDataUsageInfo.BucketsCount = info.BucketsCount
-				}
-				for k, v := range info.ObjectsSizesHistogram {
-					aggDataUsageInfo.ObjectsSizesHistogram[k] += v
 				}
-				for k, v := range info.BucketsSizes {
+				allBuckets = append(allBuckets, b)
-					aggDataUsageInfo.BucketsSizes[k] += v
+				knownBuckets[b.Name] = struct{}{}
+			}
+			wg.Add(1)
+			results = append(results, dataUsageCache{})
+			go func(i int, xl *xlObjects) {
+				updates := make(chan dataUsageCache, 1)
+				defer close(updates)
+				// Start update collector.
+				go func() {
+					defer wg.Done()
+					for info := range updates {
+						mu.Lock()
+						results[i] = info
+						mu.Unlock()
+					}
+				}()
+				// Start crawler. Blocks until done.
+				err := xl.crawlAndGetDataUsage(ctx, buckets, updates)
+				if err != nil {
+					mu.Lock()
+					if firstErr == nil {
+						firstErr = err
+					}
+					// Cancel remaining...
+					cancel()
+					mu.Unlock()
+					return
 				}
-				aggDataUsageInfo.Unlock()
+			}(len(results)-1, xlObj)
-
-			}(xlObj)
 		}
 	}
+	updateCloser := make(chan chan struct{})
+	go func() {
+		updateTicker := time.NewTicker(30 * time.Second)
+		defer updateTicker.Stop()
+		var lastUpdate time.Time
+		update := func() {
+			mu.Lock()
+			defer mu.Unlock()
+
+			// We need to merge since we will get the same buckets from each zone.
+			// Therefore to get the exact bucket sizes we must merge before we can convert.
+			allMerged := dataUsageCache{Info: dataUsageCacheInfo{Name: dataUsageRoot}}
+			for _, info := range results {
+				if info.Info.LastUpdate.IsZero() {
+					// Not filled yet.
+					return
+				}
+				allMerged.merge(info)
+			}
+			if allMerged.root() != nil && allMerged.Info.LastUpdate.After(lastUpdate) {
+				updates <- allMerged.dui(allMerged.Info.Name, allBuckets)
+				lastUpdate = allMerged.Info.LastUpdate
+			}
+		}
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case v := <-updateCloser:
+				update()
+				close(v)
+				return
+			case <-updateTicker.C:
+				update()
+			}
+		}
+	}()
+
 	wg.Wait()
+	if dataUsageDebug {
+		logger.Info(color.Green("xlZones.CrawlAndGetDataUsage:")+" Cycle scan time: %v", time.Since(t))
+	}
+	ch := make(chan struct{})
+	updateCloser <- ch
+	<-ch
 
-	aggDataUsageInfo.LastUpdate = UTCNow()
+	return firstErr
-	return aggDataUsageInfo.DataUsageInfo
 }
 
 // This function is used to undo a successful MakeBucket operation.

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/baiyubin/aliyun-sts-go-sdk v0.0.0-20180326062324-cfa1a18b161f // indirect
 	github.com/bcicen/jstream v0.0.0-20190220045926-16c1f8af81c2
 	github.com/beevik/ntp v0.2.0
+	github.com/cespare/xxhash/v2 v2.1.1
 	github.com/cheggaaa/pb v1.0.28
 	github.com/coredns/coredns v1.4.0
 	github.com/coreos/bbolt v1.3.3 // indirect
@@ -86,6 +87,7 @@ require (
 	github.com/nats-io/stan.go v0.4.5
 	github.com/ncw/directio v1.0.5
 	github.com/nsqio/go-nsq v1.0.7
+	github.com/philhofer/fwd v1.0.0 // indirect
 	github.com/pkg/errors v0.8.1
 	github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829
 	github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90 // indirect
@@ -100,6 +102,7 @@ require (
 	github.com/smartystreets/assertions v0.0.0-20190401211740-f487f9de1cd3 // indirect
 	github.com/soheilhy/cmux v0.1.4 // indirect
 	github.com/streadway/amqp v0.0.0-20190404075320-75d898a42a94
+	github.com/tinylib/msgp v1.1.1
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5 // indirect
 	github.com/ugorji/go v1.1.5-pre // indirect
 	github.com/valyala/tcplisten v0.0.0-20161114210144-ceec8f93295a

go.sum

@@ -45,6 +45,9 @@ github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kB
 github.com/boltdb/bolt v1.3.1/go.mod h1:clJnj/oiGkjum5o1McbSZDSLxVThjynRyGBgiAx27Ps=
 github.com/census-instrumentation/opencensus-proto v0.2.0 h1:LzQXZOgg4CQfE6bFvXGM30YZL1WW/M337pXml+GrcZ4=
 github.com/census-instrumentation/opencensus-proto v0.2.0/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
+github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
+github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cheggaaa/pb v1.0.28 h1:kWGpdAcSp3MxMU9CCHOwz/8V0kCHN4+9yQm2MzWuI98=
 github.com/cheggaaa/pb v1.0.28/go.mod h1:pQciLPpbU0oxA0h+VJYYLxO+XeDQb5pZijXscXHm81s=
 github.com/circonus-labs/circonus-gometrics v2.3.1+incompatible/go.mod h1:nmEj6Dob7S7YxXgwXpfOuvO54S+tGdZdw9fuRZt25Ag=
@@ -341,6 +344,8 @@ github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQ
 github.com/pascaldekloe/goe v0.1.0 h1:cBOtyMzM9HTpWjXfbbunk26uA6nG3a8n06Wieeh0MwY=
 github.com/pascaldekloe/goe v0.1.0/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
 github.com/pborman/getopt v0.0.0-20180729010549-6fdd0a2c7117/go.mod h1:85jBQOZwpVEaDAr341tbn15RS4fCAsIst0qp7i8ex1o=
+github.com/philhofer/fwd v1.0.0 h1:UbZqGr5Y38ApvM/V/jEljVxwocdweyH+vmYvRPBnbqQ=
+github.com/philhofer/fwd v1.0.0/go.mod h1:gk3iGcWd9+svBvR0sR+KPcfE+RNWozjowpeBVG3ZVNU=
 github.com/pierrec/lz4 v2.0.5+incompatible h1:2xWsjqPFWcplujydGg4WmhC/6fZqK42wMM8aXeqhl0I=
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pierrec/lz4 v2.2.6+incompatible h1:6aCX4/YZ9v8q69hTyiR7dNLnTA3fgtKHVVW5BCd5Znw=
@@ -413,6 +418,8 @@ github.com/tidwall/pretty v1.0.0 h1:HsD+QiTn7sK6flMKIvNmpqz1qrpP3Ps6jOKIKMooyg4=
 github.com/tidwall/pretty v1.0.0/go.mod h1:XNkn88O1ChpSDQmQeStsy+sBenx6DDtFZJxhVysOjyk=
 github.com/tidwall/sjson v1.0.4 h1:UcdIRXff12Lpnu3OLtZvnc03g4vH2suXDXhBwBqmzYg=
 github.com/tidwall/sjson v1.0.4/go.mod h1:bURseu1nuBkFpIES5cz6zBtjmYeOQmEESshn7VpF15Y=
+github.com/tinylib/msgp v1.1.1 h1:TnCZ3FIuKeaIy+F45+Cnp+caqdXGy4z74HvwXN+570Y=
+github.com/tinylib/msgp v1.1.1/go.mod h1:+d+yLhGm8mzTaHzB+wgMYrodPfmZrzkirds8fDWklFE=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5 h1:LnC5Kc/wtumK+WB441p7ynQJzVuNRJiqddSIE3IlSEQ=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=
 github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926/go.mod h1:9ESjWnEqriFuLhtthL60Sar/7RFoluCcXsuvEwTV5KM=

mint/run/core/aws-sdk-go/quick-tests.go

@@ -234,6 +234,11 @@ func testPresignedPutInvalidHash(s3Client *s3.S3) {
 	}
 
 	rreq, err := http.NewRequest("PUT", url, bytes.NewReader([]byte("")))
+	if err != nil {
+		failureLog(function, args, startTime, "", "AWS SDK Go presigned PUT request failed", err).Fatal()
+		return
+	}
+
 	rreq.Header.Add("X-Amz-Content-Sha256", "invalid-sha256")
 	rreq.Header.Add("Content-Type", "application/octet-stream")
 
@@ -390,6 +395,10 @@ func testSelectObject(s3Client *s3.S3) {
 		Key:    aws.String(object1),
 	}
 	_, err = s3Client.PutObject(putInput1)
+	if err != nil {
+		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go Select object failed %v", err), err).Fatal()
+		return
+	}
 
 	defer cleanup(s3Client, bucket, object1, function, args, startTime, true)
 
@@ -470,6 +479,10 @@ func testSelectObject(s3Client *s3.S3) {
 		Key:    aws.String(object2),
 	}
 	_, err = s3Client.PutObject(putInput2)
+	if err != nil {
+		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go Select object upload failed: %v", err), err).Fatal()
+		return
+	}
 
 	defer cleanup(s3Client, bucket, object2, function, args, startTime, false)
 
@@ -696,7 +709,7 @@ func testObjectTaggingErrors(s3Client *s3.S3) {
 
 	_, err = s3Client.PutObjectTagging(input)
 	if err == nil {
-		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go PUT expected to fail but succeeded"), err).Fatal()
+		failureLog(function, args, startTime, "", "AWS SDK Go PUT expected to fail but succeeded", err).Fatal()
 		return
 	}
 
@@ -727,7 +740,7 @@ func testObjectTaggingErrors(s3Client *s3.S3) {
 
 	_, err = s3Client.PutObjectTagging(input)
 	if err == nil {
-		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go PUT expected to fail but succeeded"), err).Fatal()
+		failureLog(function, args, startTime, "", "AWS SDK Go PUT expected to fail but succeeded", err).Fatal()
 		return
 	}
 
@@ -758,7 +771,7 @@ func testObjectTaggingErrors(s3Client *s3.S3) {
 
 	_, err = s3Client.PutObjectTagging(input)
 	if err == nil {
-		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go PUT expected to fail but succeeded"), err).Fatal()
+		failureLog(function, args, startTime, "", "AWS SDK Go PUT expected to fail but succeeded", err).Fatal()
 		return
 	}
 
@@ -789,7 +802,7 @@ func testObjectTaggingErrors(s3Client *s3.S3) {
 
 	_, err = s3Client.PutObjectTagging(input)
 	if err == nil {
-		failureLog(function, args, startTime, "", fmt.Sprintf("AWS SDK Go PUT expected to fail but succeeded"), err).Fatal()
+		failureLog(function, args, startTime, "", "AWS SDK Go PUT expected to fail but succeeded", err).Fatal()
 		return
 	}
 

pkg/event/errors.go

@@ -64,14 +64,14 @@ func (err ErrInvalidFilterName) Error() string {
 type ErrFilterNamePrefix struct{}
 
 func (err ErrFilterNamePrefix) Error() string {
-	return fmt.Sprintf("more than one prefix in filter rule")
+	return "more than one prefix in filter rule"
 }
 
 // ErrFilterNameSuffix - more than one suffix usage error.
 type ErrFilterNameSuffix struct{}
 
 func (err ErrFilterNameSuffix) Error() string {
-	return fmt.Sprintf("more than one suffix in filter rule")
+	return "more than one suffix in filter rule"
 }
 
 // ErrInvalidFilterValue - invalid filter value error.

pkg/event/target/amqp.go

@@ -49,6 +49,8 @@ type AMQPArgs struct {
 	QueueLimit   uint64   `json:"queueLimit"`
 }
 
+//lint:file-ignore ST1003 We cannot change these exported names.
+
 // AMQP input constants.
 const (
 	AmqpQueueDir   = "queue_dir"

pkg/handlers/forwarder.go

@@ -91,7 +91,8 @@ func (f *Forwarder) getURLFromRequest(req *http.Request) *url.URL {
 func copyURL(i *url.URL) *url.URL {
 	out := *i
 	if i.User != nil {
-		out.User = &(*i.User)
+		u := *i.User
+		out.User = &u
 	}
 	return &out
 }

pkg/ioutil/ioutil.go

@@ -78,7 +78,7 @@ type LimitWriter struct {
 	wLimit    int64
 }
 
-// Implements the io.Writer interface limiting upto
+// Write implements the io.Writer interface limiting upto
 // configured length, also skips the first N bytes.
 func (w *LimitWriter) Write(p []byte) (n int, err error) {
 	n = len(p)

pkg/lock/lock_windows.go

@@ -80,6 +80,7 @@ func TryLockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, er
 	switch flag {
 	case syscall.O_RDONLY:
 		// https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-lockfileex
+		//lint:ignore SA4016 Reasons
 		lockType = lockFileFailImmediately | 0 // Set this to enable shared lock and fail immediately.
 	}
 	return lockedOpenFile(path, flag, perm, lockType)

pkg/madmin/info-commands.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"errors"
 	"io/ioutil"
+	"math"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -155,17 +156,24 @@ var ObjectsHistogramIntervals = []objectHistogramInterval{
 	{"BETWEEN_10_MB_AND_64_MB", 1024 * 1024 * 10, 1024*1024*64 - 1},
 	{"BETWEEN_64_MB_AND_128_MB", 1024 * 1024 * 64, 1024*1024*128 - 1},
 	{"BETWEEN_128_MB_AND_512_MB", 1024 * 1024 * 128, 1024*1024*512 - 1},
-	{"GREATER_THAN_512_MB", 1024 * 1024 * 512, -1},
+	{"GREATER_THAN_512_MB", 1024 * 1024 * 512, math.MaxInt64},
 }
 
 // DataUsageInfo represents data usage of an Object API
 type DataUsageInfo struct {
-	LastUpdate            time.Time         `json:"lastUpdate"`
+	// LastUpdate is the timestamp of when the data usage info was last updated.
-	ObjectsCount          uint64            `json:"objectsCount"`
+	// This does not indicate a full scan.
-	ObjectsTotalSize      uint64            `json:"objectsTotalSize"`
+	LastUpdate       time.Time `json:"lastUpdate"`
+	ObjectsCount     uint64    `json:"objectsCount"`
+	ObjectsTotalSize uint64    `json:"objectsTotalSize"`
+
+	// ObjectsSizesHistogram contains information on objects across all buckets.
+	// See ObjectsHistogramIntervals.
 	ObjectsSizesHistogram map[string]uint64 `json:"objectsSizesHistogram"`
 
-	BucketsCount uint64            `json:"bucketsCount"`
+	BucketsCount uint64 `json:"bucketsCount"`
+
+	// BucketsSizes is "bucket name" -> size.
 	BucketsSizes map[string]uint64 `json:"bucketsSizes"`
 }
 

pkg/s3select/sql/utils.go

@@ -50,7 +50,7 @@ func (e *JSONPathElement) String() string {
 	return ""
 }
 
-// Removes double quotes in quoted identifiers
+// String removes double quotes in quoted identifiers
 func (i *Identifier) String() string {
 	if i.Unquoted != nil {
 		return *i.Unquoted