X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/495a7df016f63ae348000b1c046f8e1c5f1c5903..f04693da1811e670d4cbb981debeecf14d79137c:/services/keepstore/s3_volume.go

diff --git a/services/keepstore/s3_volume.go b/services/keepstore/s3_volume.go
index d34b8772c5..22a38e2085 100644
--- a/services/keepstore/s3_volume.go
+++ b/services/keepstore/s3_volume.go
@@ -1,204 +1,68 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
 	"encoding/base64"
 	"encoding/hex"
-	"flag"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"os"
 	"regexp"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"git.curoverse.com/arvados.git/sdk/go/arvados"
 	"github.com/AdRoll/goamz/aws"
 	"github.com/AdRoll/goamz/s3"
-	log "github.com/Sirupsen/logrus"
-)
-
-const (
-	s3DefaultReadTimeout    = arvados.Duration(10 * time.Minute)
-	s3DefaultConnectTimeout = arvados.Duration(time.Minute)
-)
-
-var (
-	// ErrS3TrashDisabled is returned by Trash if that operation
-	// is impossible with the current config.
-	ErrS3TrashDisabled = fmt.Errorf("trash function is disabled because -trash-lifetime=0 and -s3-unsafe-delete=false")
-
-	s3AccessKeyFile string
-	s3SecretKeyFile string
-	s3RegionName    string
-	s3Endpoint      string
-	s3Replication   int
-	s3UnsafeDelete  bool
-	s3RaceWindow    time.Duration
-
-	s3ACL = s3.Private
-)
-
-const (
-	maxClockSkew  = 600 * time.Second
-	nearlyRFC1123 = "Mon, 2 Jan 2006 15:04:05 GMT"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
 )
 
-type s3VolumeAdder struct {
-	*Config
-}
-
-// String implements flag.Value
-func (s *s3VolumeAdder) String() string {
-	return "-"
+func init() {
+	driver["S3"] = newS3Volume
 }
 
-func (s *s3VolumeAdder) Set(bucketName string) error {
-	if bucketName == "" {
-		return fmt.Errorf("no container name given")
-	}
-	if s3AccessKeyFile == "" || s3SecretKeyFile == "" {
-		return fmt.Errorf("-s3-access-key-file and -s3-secret-key-file arguments must given before -s3-bucket-volume")
-	}
-	if deprecated.flagSerializeIO {
-		log.Print("Notice: -serialize is not supported by s3-bucket volumes.")
+func newS3Volume(cluster *arvados.Cluster, volume arvados.Volume, logger logrus.FieldLogger, metrics *volumeMetricsVecs) (Volume, error) {
+	v := &S3Volume{cluster: cluster, volume: volume, logger: logger, metrics: metrics}
+	err := json.Unmarshal(volume.DriverParameters, &v)
+	if err != nil {
+		return nil, err
 	}
-	s.Config.Volumes = append(s.Config.Volumes, &S3Volume{
-		Bucket:        bucketName,
-		AccessKeyFile: s3AccessKeyFile,
-		SecretKeyFile: s3SecretKeyFile,
-		Endpoint:      s3Endpoint,
-		Region:        s3RegionName,
-		RaceWindow:    arvados.Duration(s3RaceWindow),
-		S3Replication: s3Replication,
-		UnsafeDelete:  s3UnsafeDelete,
-		ReadOnly:      deprecated.flagReadonly,
-		IndexPageSize: 1000,
-	})
-	return nil
+	return v, v.check()
 }
 
-func s3regions() (okList []string) {
-	for r := range aws.Regions {
-		okList = append(okList, r)
+func (v *S3Volume) check() error {
+	if v.Bucket == "" || v.AccessKey == "" || v.SecretKey == "" {
+		return errors.New("DriverParameters: Bucket, AccessKey, and SecretKey must be provided")
 	}
-	return
-}
-
-func init() {
-	VolumeTypes = append(VolumeTypes, func() VolumeWithExamples { return &S3Volume{} })
-
-	flag.Var(&s3VolumeAdder{theConfig},
-		"s3-bucket-volume",
-		"Use the given bucket as a storage volume. Can be given multiple times.")
-	flag.StringVar(
-		&s3RegionName,
-		"s3-region",
-		"",
-		fmt.Sprintf("AWS region used for subsequent -s3-bucket-volume arguments. Allowed values are %+q.", s3regions()))
-	flag.StringVar(
-		&s3Endpoint,
-		"s3-endpoint",
-		"",
-		"Endpoint URL used for subsequent -s3-bucket-volume arguments. If blank, use the AWS endpoint corresponding to the -s3-region argument. For Google Storage, use \"https://storage.googleapis.com\".")
-	flag.StringVar(
-		&s3AccessKeyFile,
-		"s3-access-key-file",
-		"",
-		"`File` containing the access key used for subsequent -s3-bucket-volume arguments.")
-	flag.StringVar(
-		&s3SecretKeyFile,
-		"s3-secret-key-file",
-		"",
-		"`File` containing the secret key used for subsequent -s3-bucket-volume arguments.")
-	flag.DurationVar(
-		&s3RaceWindow,
-		"s3-race-window",
-		24*time.Hour,
-		"Maximum eventual consistency latency for subsequent -s3-bucket-volume arguments.")
-	flag.IntVar(
-		&s3Replication,
-		"s3-replication",
-		2,
-		"Replication level reported to clients for subsequent -s3-bucket-volume arguments.")
-	flag.BoolVar(
-		&s3UnsafeDelete,
-		"s3-unsafe-delete",
-		false,
-		"EXPERIMENTAL. Enable deletion (garbage collection), even though there are known race conditions that can cause data loss.")
-}
-
-// S3Volume implements Volume using an S3 bucket.
-type S3Volume struct {
-	AccessKeyFile      string
-	SecretKeyFile      string
-	Endpoint           string
-	Region             string
-	Bucket             string
-	LocationConstraint bool
-	IndexPageSize      int
-	S3Replication      int
-	ConnectTimeout     arvados.Duration
-	ReadTimeout        arvados.Duration
-	RaceWindow         arvados.Duration
-	ReadOnly           bool
-	UnsafeDelete       bool
-
-	bucket *s3bucket
-
-	startOnce sync.Once
-}
-
-// Examples implements VolumeWithExamples.
-func (*S3Volume) Examples() []Volume {
-	return []Volume{
-		&S3Volume{
-			AccessKeyFile:  "/etc/aws_s3_access_key.txt",
-			SecretKeyFile:  "/etc/aws_s3_secret_key.txt",
-			Endpoint:       "",
-			Region:         "us-east-1",
-			Bucket:         "example-bucket-name",
-			IndexPageSize:  1000,
-			S3Replication:  2,
-			RaceWindow:     arvados.Duration(24 * time.Hour),
-			ConnectTimeout: arvados.Duration(time.Minute),
-			ReadTimeout:    arvados.Duration(5 * time.Minute),
-		},
-		&S3Volume{
-			AccessKeyFile:  "/etc/gce_s3_access_key.txt",
-			SecretKeyFile:  "/etc/gce_s3_secret_key.txt",
-			Endpoint:       "https://storage.googleapis.com",
-			Region:         "",
-			Bucket:         "example-bucket-name",
-			IndexPageSize:  1000,
-			S3Replication:  2,
-			RaceWindow:     arvados.Duration(24 * time.Hour),
-			ConnectTimeout: arvados.Duration(time.Minute),
-			ReadTimeout:    arvados.Duration(5 * time.Minute),
-		},
+	if v.IndexPageSize == 0 {
+		v.IndexPageSize = 1000
+	}
+	if v.RaceWindow < 0 {
+		return errors.New("DriverParameters: RaceWindow must not be negative")
 	}
-}
-
-// Type implements Volume.
-func (*S3Volume) Type() string {
-	return "S3"
-}
 
-// Start populates private fields and verifies the configuration is
-// valid.
-func (v *S3Volume) Start() error {
 	region, ok := aws.Regions[v.Region]
 	if v.Endpoint == "" {
 		if !ok {
-			return fmt.Errorf("unrecognized region %+q; try specifying -s3-endpoint instead", v.Region)
+			return fmt.Errorf("unrecognized region %+q; try specifying endpoint instead", v.Region)
 		}
 	} else if ok {
 		return fmt.Errorf("refusing to use AWS region name %+q with endpoint %+q; "+
-			"specify empty endpoint (\"-s3-endpoint=\") or use a different region name", v.Region, v.Endpoint)
+			"specify empty endpoint or use a different region name", v.Region, v.Endpoint)
 	} else {
 		region = aws.Region{
 			Name:                 v.Region,
@@ -207,15 +71,9 @@ func (v *S3Volume) Start() error {
 		}
 	}
 
-	var err error
-	var auth aws.Auth
-	auth.AccessKey, err = readKeyFromFile(v.AccessKeyFile)
-	if err != nil {
-		return err
-	}
-	auth.SecretKey, err = readKeyFromFile(v.SecretKeyFile)
-	if err != nil {
-		return err
+	auth := aws.Auth{
+		AccessKey: v.AccessKey,
+		SecretKey: v.SecretKey,
 	}
 
 	// Zero timeouts mean "wait forever", which is a bad
@@ -228,6 +86,10 @@ func (v *S3Volume) Start() error {
 	}
 
 	client := s3.New(auth, region)
+	if region.EC2Endpoint.Signer == aws.V4Signature {
+		// Currently affects only eu-central-1
+		client.Signature = aws.V4Signature
+	}
 	client.ConnectTimeout = time.Duration(v.ConnectTimeout)
 	client.ReadTimeout = time.Duration(v.ReadTimeout)
 	v.bucket = &s3bucket{
@@ -236,9 +98,67 @@ func (v *S3Volume) Start() error {
 			Name: v.Bucket,
 		},
 	}
+	// Set up prometheus metrics
+	lbls := prometheus.Labels{"device_id": v.GetDeviceID()}
+	v.bucket.stats.opsCounters, v.bucket.stats.errCounters, v.bucket.stats.ioBytes = v.metrics.getCounterVecsFor(lbls)
+
 	return nil
 }
 
+const (
+	s3DefaultReadTimeout    = arvados.Duration(10 * time.Minute)
+	s3DefaultConnectTimeout = arvados.Duration(time.Minute)
+)
+
+var (
+	// ErrS3TrashDisabled is returned by Trash if that operation
+	// is impossible with the current config.
+	ErrS3TrashDisabled = fmt.Errorf("trash function is disabled because -trash-lifetime=0 and -s3-unsafe-delete=false")
+
+	s3ACL = s3.Private
+
+	zeroTime time.Time
+)
+
+const (
+	maxClockSkew  = 600 * time.Second
+	nearlyRFC1123 = "Mon, 2 Jan 2006 15:04:05 GMT"
+)
+
+func s3regions() (okList []string) {
+	for r := range aws.Regions {
+		okList = append(okList, r)
+	}
+	return
+}
+
+// S3Volume implements Volume using an S3 bucket.
+type S3Volume struct {
+	AccessKey          string
+	SecretKey          string
+	Endpoint           string
+	Region             string
+	Bucket             string
+	LocationConstraint bool
+	IndexPageSize      int
+	ConnectTimeout     arvados.Duration
+	ReadTimeout        arvados.Duration
+	RaceWindow         arvados.Duration
+	UnsafeDelete       bool
+
+	cluster   *arvados.Cluster
+	volume    arvados.Volume
+	logger    logrus.FieldLogger
+	metrics   *volumeMetricsVecs
+	bucket    *s3bucket
+	startOnce sync.Once
+}
+
+// GetDeviceID returns a globally unique ID for the storage bucket.
+func (v *S3Volume) GetDeviceID() string {
+	return "s3://" + v.Endpoint + "/" + v.Bucket
+}
+
 func (v *S3Volume) getReaderWithContext(ctx context.Context, loc string) (rdr io.ReadCloser, err error) {
 	ready := make(chan bool)
 	go func() {
@@ -249,7 +169,7 @@ func (v *S3Volume) getReaderWithContext(ctx context.Context, loc string) (rdr io
 	case <-ready:
 		return
 	case <-ctx.Done():
-		theConfig.debugLogf("s3: abandoning getReader(): %s", ctx.Err())
+		v.logger.Debugf("s3: abandoning getReader(): %s", ctx.Err())
 		go func() {
 			<-ready
 			if err == nil {
@@ -317,11 +237,11 @@ func (v *S3Volume) Get(ctx context.Context, loc string, buf []byte) (int, error)
 	}()
 	select {
 	case <-ctx.Done():
-		theConfig.debugLogf("s3: interrupting ReadFull() with Close() because %s", ctx.Err())
+		v.logger.Debugf("s3: interrupting ReadFull() with Close() because %s", ctx.Err())
 		rdr.Close()
 		// Must wait for ReadFull to return, to ensure it
 		// doesn't write to buf after we return.
-		theConfig.debugLogf("s3: waiting for ReadFull() to fail")
+		v.logger.Debug("s3: waiting for ReadFull() to fail")
 		<-ready
 		return 0, ctx.Err()
 	case <-ready:
@@ -331,6 +251,40 @@ func (v *S3Volume) Get(ctx context.Context, loc string, buf []byte) (int, error)
 
 // Compare the given data with the stored data.
 func (v *S3Volume) Compare(ctx context.Context, loc string, expect []byte) error {
+	errChan := make(chan error, 1)
+	go func() {
+		_, err := v.bucket.Head("recent/"+loc, nil)
+		errChan <- err
+	}()
+	var err error
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case err = <-errChan:
+	}
+	if err != nil {
+		// Checking for "loc" itself here would interfere with
+		// future GET requests.
+		//
+		// On AWS, if X doesn't exist, a HEAD or GET request
+		// for X causes X's non-existence to be cached. Thus,
+		// if we test for X, then create X and return a
+		// signature to our client, the client might still get
+		// 404 from all keepstores when trying to read it.
+		//
+		// To avoid this, we avoid doing HEAD X or GET X until
+		// we know X has been written.
+		//
+		// Note that X might exist even though recent/X
+		// doesn't: for example, the response to HEAD recent/X
+		// might itself come from a stale cache. In such
+		// cases, we will return a false negative and
+		// PutHandler might needlessly create another replica
+		// on a different volume. That's not ideal, but it's
+		// better than passing the eventually-consistent
+		// problem on to our clients.
+		return v.translateError(err)
+	}
 	rdr, err := v.getReaderWithContext(ctx, loc)
 	if err != nil {
 		return err
@@ -341,7 +295,7 @@ func (v *S3Volume) Compare(ctx context.Context, loc string, expect []byte) error
 
 // Put writes a block.
 func (v *S3Volume) Put(ctx context.Context, loc string, block []byte) error {
-	if v.ReadOnly {
+	if v.volume.ReadOnly {
 		return MethodDisabledError
 	}
 	var opts s3.Options
@@ -352,6 +306,14 @@ func (v *S3Volume) Put(ctx context.Context, loc string, block []byte) error {
 			return err
 		}
 		opts.ContentMD5 = base64.StdEncoding.EncodeToString(md5)
+		// In AWS regions that use V4 signatures, we need to
+		// provide ContentSHA256 up front. Otherwise, the S3
+		// library reads the request body (from our buffer)
+		// into another new buffer in order to compute the
+		// SHA256 before sending the request -- which would
+		// mean consuming 128 MiB of memory for the duration
+		// of a 64 MiB write.
+		opts.ContentSHA256 = fmt.Sprintf("%x", sha256.Sum256(block))
 	}
 
 	// Send the block data through a pipe, so that (if we need to)
@@ -369,7 +331,7 @@ func (v *S3Volume) Put(ctx context.Context, loc string, block []byte) error {
 	go func() {
 		defer func() {
 			if ctx.Err() != nil {
-				theConfig.debugLogf("%s: abandoned PutReader goroutine finished with err: %s", v, err)
+				v.logger.Debugf("%s: abandoned PutReader goroutine finished with err: %s", v, err)
 			}
 		}()
 		defer close(ready)
@@ -377,28 +339,30 @@ func (v *S3Volume) Put(ctx context.Context, loc string, block []byte) error {
 		if err != nil {
 			return
 		}
-		err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
+		err = v.bucket.PutReader("recent/"+loc, nil, 0, "application/octet-stream", s3ACL, s3.Options{})
 	}()
 	select {
 	case <-ctx.Done():
-		theConfig.debugLogf("%s: taking PutReader's input away: %s", v, ctx.Err())
+		v.logger.Debugf("%s: taking PutReader's input away: %s", v, ctx.Err())
 		// Our pipe might be stuck in Write(), waiting for
-		// io.Copy() to read. If so, un-stick it. This means
+		// PutReader() to read. If so, un-stick it. This means
 		// PutReader will get corrupt data, but that's OK: the
 		// size and MD5 won't match, so the write will fail.
 		go io.Copy(ioutil.Discard, bufr)
 		// CloseWithError() will return once pending I/O is done.
 		bufw.CloseWithError(ctx.Err())
-		theConfig.debugLogf("%s: abandoning PutReader goroutine", v)
+		v.logger.Debugf("%s: abandoning PutReader goroutine", v)
 		return ctx.Err()
 	case <-ready:
+		// Unblock pipe in case PutReader did not consume it.
+		io.Copy(ioutil.Discard, bufr)
 		return v.translateError(err)
 	}
 }
 
 // Touch sets the timestamp for the given locator to the current time.
 func (v *S3Volume) Touch(loc string) error {
-	if v.ReadOnly {
+	if v.volume.ReadOnly {
 		return MethodDisabledError
 	}
 	_, err := v.bucket.Head(loc, nil)
@@ -409,7 +373,7 @@ func (v *S3Volume) Touch(loc string) error {
 	} else if err != nil {
 		return err
 	}
-	err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
+	err = v.bucket.PutReader("recent/"+loc, nil, 0, "application/octet-stream", s3ACL, s3.Options{})
 	return v.translateError(err)
 }
 
@@ -423,7 +387,7 @@ func (v *S3Volume) Mtime(loc string) (time.Time, error) {
 	err = v.translateError(err)
 	if os.IsNotExist(err) {
 		// The data object X exists, but recent/X is missing.
-		err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
+		err = v.bucket.PutReader("recent/"+loc, nil, 0, "application/octet-stream", s3ACL, s3.Options{})
 		if err != nil {
 			log.Printf("error: creating %q: %s", "recent/"+loc, err)
 			return zeroTime, v.translateError(err)
@@ -449,16 +413,15 @@ func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error {
 		Bucket:   v.bucket.Bucket,
 		Prefix:   prefix,
 		PageSize: v.IndexPageSize,
+		Stats:    &v.bucket.stats,
 	}
 	recentL := s3Lister{
 		Bucket:   v.bucket.Bucket,
 		Prefix:   "recent/" + prefix,
 		PageSize: v.IndexPageSize,
+		Stats:    &v.bucket.stats,
 	}
-	v.bucket.stats.Tick(&v.bucket.stats.Ops, &v.bucket.stats.ListOps)
-	v.bucket.stats.Tick(&v.bucket.stats.Ops, &v.bucket.stats.ListOps)
-	for data, recent := dataL.First(), recentL.First(); data != nil; data = dataL.Next() {
-		v.bucket.stats.Tick(&v.bucket.stats.Ops, &v.bucket.stats.ListOps)
+	for data, recent := dataL.First(), recentL.First(); data != nil && dataL.Error() == nil; data = dataL.Next() {
 		if data.Key >= "g" {
 			// Conveniently, "recent/*" and "trash/*" are
 			// lexically greater than all hex-encoded data
@@ -477,15 +440,13 @@ func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error {
 		stamp := data
 
 		// Advance to the corresponding recent/X marker, if any
-		for recent != nil {
+		for recent != nil && recentL.Error() == nil {
 			if cmp := strings.Compare(recent.Key[7:], data.Key); cmp < 0 {
 				recent = recentL.Next()
-				v.bucket.stats.Tick(&v.bucket.stats.Ops, &v.bucket.stats.ListOps)
 				continue
 			} else if cmp == 0 {
 				stamp = recent
 				recent = recentL.Next()
-				v.bucket.stats.Tick(&v.bucket.stats.Ops, &v.bucket.stats.ListOps)
 				break
 			} else {
 				// recent/X marker is missing: we'll
@@ -494,27 +455,30 @@ func (v *S3Volume) IndexTo(prefix string, writer io.Writer) error {
 				break
 			}
 		}
+		if err := recentL.Error(); err != nil {
+			return err
+		}
 		t, err := time.Parse(time.RFC3339, stamp.LastModified)
 		if err != nil {
 			return err
 		}
 		fmt.Fprintf(writer, "%s+%d %d\n", data.Key, data.Size, t.UnixNano())
 	}
-	return nil
+	return dataL.Error()
 }
 
 // Trash a Keep block.
 func (v *S3Volume) Trash(loc string) error {
-	if v.ReadOnly {
+	if v.volume.ReadOnly {
 		return MethodDisabledError
 	}
 	if t, err := v.Mtime(loc); err != nil {
 		return err
-	} else if time.Since(t) < theConfig.BlobSignatureTTL.Duration() {
+	} else if time.Since(t) < v.cluster.Collections.BlobSigningTTL.Duration() {
 		return nil
 	}
-	if theConfig.TrashLifetime == 0 {
-		if !s3UnsafeDelete {
+	if v.cluster.Collections.BlobTrashLifetime == 0 {
+		if !v.UnsafeDelete {
 			return ErrS3TrashDisabled
 		}
 		return v.translateError(v.bucket.Del(loc))
@@ -549,7 +513,7 @@ func (v *S3Volume) checkRaceWindow(loc string) error {
 		// Can't parse timestamp
 		return err
 	}
-	safeWindow := t.Add(theConfig.TrashLifetime.Duration()).Sub(time.Now().Add(time.Duration(v.RaceWindow)))
+	safeWindow := t.Add(v.cluster.Collections.BlobTrashLifetime.Duration()).Sub(time.Now().Add(time.Duration(v.RaceWindow)))
 	if safeWindow <= 0 {
 		// We can't count on "touch trash/X" to prolong
 		// trash/X's lifetime. The new timestamp might not
@@ -572,8 +536,10 @@ func (v *S3Volume) safeCopy(dst, src string) error {
 		MetadataDirective: "REPLACE",
 	}, v.bucket.Name+"/"+src)
 	err = v.translateError(err)
-	if err != nil {
+	if os.IsNotExist(err) {
 		return err
+	} else if err != nil {
+		return fmt.Errorf("PutCopy(%q ← %q): %s", dst, v.bucket.Name+"/"+src, err)
 	}
 	if t, err := time.Parse(time.RFC3339Nano, resp.LastModified); err != nil {
 		return fmt.Errorf("PutCopy succeeded but did not return a timestamp: %q: %s", resp.LastModified, err)
@@ -605,7 +571,7 @@ func (v *S3Volume) Untrash(loc string) error {
 	if err != nil {
 		return err
 	}
-	err = v.bucket.Put("recent/"+loc, nil, "application/octet-stream", s3ACL, s3.Options{})
+	err = v.bucket.PutReader("recent/"+loc, nil, 0, "application/octet-stream", s3ACL, s3.Options{})
 	return v.translateError(err)
 }
 
@@ -630,18 +596,6 @@ func (v *S3Volume) String() string {
 	return fmt.Sprintf("s3-bucket:%+q", v.Bucket)
 }
 
-// Writable returns false if all future Put, Mtime, and Delete calls
-// are expected to fail.
-func (v *S3Volume) Writable() bool {
-	return !v.ReadOnly
-}
-
-// Replication returns the storage redundancy of the underlying
-// device. Configured via command line flag.
-func (v *S3Volume) Replication() int {
-	return v.S3Replication
-}
-
 var s3KeepBlockRegexp = regexp.MustCompile(`^[0-9a-f]{32}$`)
 
 func (v *S3Volume) isKeepBlock(s string) bool {
@@ -678,13 +632,13 @@ func (v *S3Volume) fixRace(loc string) bool {
 	}
 
 	ageWhenTrashed := trashTime.Sub(recentTime)
-	if ageWhenTrashed >= theConfig.BlobSignatureTTL.Duration() {
+	if ageWhenTrashed >= v.cluster.Collections.BlobSigningTTL.Duration() {
 		// No evidence of a race: block hasn't been written
 		// since it became eligible for Trash. No fix needed.
 		return false
 	}
 
-	log.Printf("notice: fixRace: %q: trashed at %s but touched at %s (age when trashed = %s < %s)", loc, trashTime, recentTime, ageWhenTrashed, theConfig.BlobSignatureTTL)
+	log.Printf("notice: fixRace: %q: trashed at %s but touched at %s (age when trashed = %s < %s)", loc, trashTime, recentTime, ageWhenTrashed, v.cluster.Collections.BlobSigningTTL)
 	log.Printf("notice: fixRace: copying %q to %q to recover from race between Put/Touch and Trash", "recent/"+loc, loc)
 	err = v.safeCopy(loc, "trash/"+loc)
 	if err != nil {
@@ -712,28 +666,27 @@ func (v *S3Volume) translateError(err error) error {
 // EmptyTrash looks for trashed blocks that exceeded TrashLifetime
 // and deletes them from the volume.
 func (v *S3Volume) EmptyTrash() {
+	if v.cluster.Collections.BlobDeleteConcurrency < 1 {
+		return
+	}
+
 	var bytesInTrash, blocksInTrash, bytesDeleted, blocksDeleted int64
 
-	// Use a merge sort to find matching sets of trash/X and recent/X.
-	trashL := s3Lister{
-		Bucket:   v.bucket.Bucket,
-		Prefix:   "trash/",
-		PageSize: v.IndexPageSize,
-	}
 	// Define "ready to delete" as "...when EmptyTrash started".
 	startT := time.Now()
-	for trash := trashL.First(); trash != nil; trash = trashL.Next() {
+
+	emptyOneKey := func(trash *s3.Key) {
 		loc := trash.Key[6:]
 		if !v.isKeepBlock(loc) {
-			continue
+			return
 		}
-		bytesInTrash += trash.Size
-		blocksInTrash++
+		atomic.AddInt64(&bytesInTrash, trash.Size)
+		atomic.AddInt64(&blocksInTrash, 1)
 
 		trashT, err := time.Parse(time.RFC3339, trash.LastModified)
 		if err != nil {
 			log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, trash.Key, trash.LastModified, err)
-			continue
+			return
 		}
 		recent, err := v.bucket.Head("recent/"+loc, nil)
 		if err != nil && os.IsNotExist(v.translateError(err)) {
@@ -742,18 +695,18 @@ func (v *S3Volume) EmptyTrash() {
 			if err != nil {
 				log.Printf("error: %s: EmptyTrash: Untrash(%q): %s", v, loc, err)
 			}
-			continue
+			return
 		} else if err != nil {
 			log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err)
-			continue
+			return
 		}
 		recentT, err := v.lastModified(recent)
 		if err != nil {
 			log.Printf("warning: %s: EmptyTrash: %q: parse %q: %s", v, "recent/"+loc, recent.Header.Get("Last-Modified"), err)
-			continue
+			return
 		}
-		if trashT.Sub(recentT) < theConfig.BlobSignatureTTL.Duration() {
-			if age := startT.Sub(recentT); age >= theConfig.BlobSignatureTTL.Duration()-time.Duration(v.RaceWindow) {
+		if trashT.Sub(recentT) < v.cluster.Collections.BlobSigningTTL.Duration() {
+			if age := startT.Sub(recentT); age >= v.cluster.Collections.BlobSigningTTL.Duration()-time.Duration(v.RaceWindow) {
 				// recent/loc is too old to protect
 				// loc from being Trashed again during
 				// the raceWindow that starts if we
@@ -765,39 +718,68 @@ func (v *S3Volume) EmptyTrash() {
 				log.Printf("notice: %s: EmptyTrash: detected old race for %q, calling fixRace + Touch", v, loc)
 				v.fixRace(loc)
 				v.Touch(loc)
-				continue
+				return
 			}
 			_, err := v.bucket.Head(loc, nil)
 			if os.IsNotExist(err) {
 				log.Printf("notice: %s: EmptyTrash: detected recent race for %q, calling fixRace", v, loc)
 				v.fixRace(loc)
-				continue
+				return
 			} else if err != nil {
 				log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, loc, err)
-				continue
+				return
 			}
 		}
-		if startT.Sub(trashT) < theConfig.TrashLifetime.Duration() {
-			continue
+		if startT.Sub(trashT) < v.cluster.Collections.BlobTrashLifetime.Duration() {
+			return
 		}
 		err = v.bucket.Del(trash.Key)
 		if err != nil {
 			log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, trash.Key, err)
-			continue
+			return
 		}
-		bytesDeleted += trash.Size
-		blocksDeleted++
+		atomic.AddInt64(&bytesDeleted, trash.Size)
+		atomic.AddInt64(&blocksDeleted, 1)
 
 		_, err = v.bucket.Head(loc, nil)
-		if os.IsNotExist(err) {
-			err = v.bucket.Del("recent/" + loc)
-			if err != nil {
-				log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, "recent/"+loc, err)
-			}
-		} else if err != nil {
-			log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, "recent/"+loc, err)
+		if err == nil {
+			log.Printf("warning: %s: EmptyTrash: HEAD %q succeeded immediately after deleting %q", v, loc, loc)
+			return
+		}
+		if !os.IsNotExist(v.translateError(err)) {
+			log.Printf("warning: %s: EmptyTrash: HEAD %q: %s", v, loc, err)
+			return
 		}
+		err = v.bucket.Del("recent/" + loc)
+		if err != nil {
+			log.Printf("warning: %s: EmptyTrash: deleting %q: %s", v, "recent/"+loc, err)
+		}
+	}
+
+	var wg sync.WaitGroup
+	todo := make(chan *s3.Key, v.cluster.Collections.BlobDeleteConcurrency)
+	for i := 0; i < v.cluster.Collections.BlobDeleteConcurrency; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for key := range todo {
+				emptyOneKey(key)
+			}
+		}()
 	}
+
+	trashL := s3Lister{
+		Bucket:   v.bucket.Bucket,
+		Prefix:   "trash/",
+		PageSize: v.IndexPageSize,
+		Stats:    &v.bucket.stats,
+	}
+	for trash := trashL.First(); trash != nil; trash = trashL.Next() {
+		todo <- trash
+	}
+	close(todo)
+	wg.Wait()
+
 	if err := trashL.Error(); err != nil {
 		log.Printf("error: %s: EmptyTrash: lister: %s", v, err)
 	}
@@ -808,6 +790,7 @@ type s3Lister struct {
 	Bucket     *s3.Bucket
 	Prefix     string
 	PageSize   int
+	Stats      *s3bucketStats
 	nextMarker string
 	buf        []s3.Key
 	err        error
@@ -836,6 +819,8 @@ func (lister *s3Lister) Error() error {
 }
 
 func (lister *s3Lister) getPage() {
+	lister.Stats.TickOps("list")
+	lister.Stats.Tick(&lister.Stats.Ops, &lister.Stats.ListOps)
 	resp, err := lister.Bucket.List(lister.Prefix, "", lister.nextMarker, lister.PageSize)
 	lister.nextMarker = ""
 	if err != nil {
@@ -871,6 +856,7 @@ type s3bucket struct {
 
 func (b *s3bucket) GetReader(path string) (io.ReadCloser, error) {
 	rdr, err := b.Bucket.GetReader(path)
+	b.stats.TickOps("get")
 	b.stats.Tick(&b.stats.Ops, &b.stats.GetOps)
 	b.stats.TickErr(err)
 	return NewCountingReader(rdr, b.stats.TickInBytes), err
@@ -878,20 +864,26 @@ func (b *s3bucket) GetReader(path string) (io.ReadCloser, error) {
 
 func (b *s3bucket) Head(path string, headers map[string][]string) (*http.Response, error) {
 	resp, err := b.Bucket.Head(path, headers)
+	b.stats.TickOps("head")
 	b.stats.Tick(&b.stats.Ops, &b.stats.HeadOps)
 	b.stats.TickErr(err)
 	return resp, err
 }
 
 func (b *s3bucket) PutReader(path string, r io.Reader, length int64, contType string, perm s3.ACL, options s3.Options) error {
-	err := b.Bucket.PutReader(path, NewCountingReader(r, b.stats.TickOutBytes), length, contType, perm, options)
-	b.stats.Tick(&b.stats.Ops, &b.stats.PutOps)
-	b.stats.TickErr(err)
-	return err
-}
-
-func (b *s3bucket) Put(path string, data []byte, contType string, perm s3.ACL, options s3.Options) error {
-	err := b.Bucket.PutReader(path, NewCountingReader(bytes.NewBuffer(data), b.stats.TickOutBytes), int64(len(data)), contType, perm, options)
+	if length == 0 {
+		// goamz will only send Content-Length: 0 when reader
+		// is nil due to net.http.Request.ContentLength
+		// behavior.  Otherwise, Content-Length header is
+		// omitted which will cause some S3 services
+		// (including AWS and Ceph RadosGW) to fail to create
+		// empty objects.
+		r = nil
+	} else {
+		r = NewCountingReader(r, b.stats.TickOutBytes)
+	}
+	err := b.Bucket.PutReader(path, r, length, contType, perm, options)
+	b.stats.TickOps("put")
 	b.stats.Tick(&b.stats.Ops, &b.stats.PutOps)
 	b.stats.TickErr(err)
 	return err
@@ -899,6 +891,7 @@ func (b *s3bucket) Put(path string, data []byte, contType string, perm s3.ACL, o
 
 func (b *s3bucket) Del(path string) error {
 	err := b.Bucket.Del(path)
+	b.stats.TickOps("delete")
 	b.stats.Tick(&b.stats.Ops, &b.stats.DelOps)
 	b.stats.TickErr(err)
 	return err