Files
seaweedfs/weed/command/filer_remote_sync_dir.go
T
Chris Lu 80dae68dbf fix: write the new key when a remote-synced file is renamed (#11270)
* refactor: extract update event handling into processUpdateEvent

Pull the OldEntry/NewEntry update branch of the remote sync event
processor into its own function so the rename skip logic can be
exercised by tests with stub clients. No behavior change.

* test: reproduce remote sync rename dropping the new key

A rename under a remote mount arrives as an update whose NewEntry
inherits the source RemoteEntry. shouldSendToRemote returns false
for it, so processUpdateEvent skipped the event without writing the
new key, while the filer had already deleted the old object. The test
runs such an event through processUpdateEvent and expects both a
delete of the old key and a write of the new one. Fails before the
fix. See #11261.

* fix: write the new key when a remote-synced file is renamed

A rename under a remote mount arrives as an update whose NewEntry
inherits the source RemoteEntry, so shouldSendToRemote returns false
(RemoteMtime >= Mtime) and processUpdateEvent skipped the event.
That skip is only valid when the destination key is unchanged; a path
change always needs a write, and the delete-old/write-new handling
below the early return is exactly what a rename needs. Guard the skip
with proto.Equal(oldDest, dest) so a rename falls through to it.

Fixes #11261.

* fix: skip empty upload when renaming a remote-only entry

A remote-only entry (no local chunks or content, data lives only on
the remote object) carries a positive RemoteSize but nothing for
NewFileReader to read. After the previous commit lets a rename fall
through to the delete-old/write-new path, such a rename would upload
EOF and create a zero-byte object at the new key, then stamp it as
synced. Guard the write so a path change on a remote-only entry skips
the upload instead of replacing the file with zero bytes. The filer
has already deleted the old object, so the data is gone regardless;
this avoids leaving a misleading empty object behind.

* fix: propagate old-key delete errors except already-deleted

When deleting the old key on a rename fails for a non-multipart entry,
the error was swallowed and the write proceeded, which could leave both
remote keys. Return the error so MetadataProcessor retries the event.

The filer deletes the source remote object synchronously during the
rename, so the sync delete is redundant and the object may already be
gone. GCS reports that as ErrRemoteObjectNotFound (unlike S3/Azure,
whose deletes are idempotent), so treat it as a successful deletion and
continue to retriedWriteFile rather than pinning the sync offset.
2026-09-11 10:47:37 -07:00

525 lines
21 KiB
Go

package command
import (
"bytes"
"context"
"errors"
"fmt"
"os"
"strings"
"time"
"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
"github.com/seaweedfs/seaweedfs/weed/filer"
"github.com/seaweedfs/seaweedfs/weed/glog"
"github.com/seaweedfs/seaweedfs/weed/pb"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/pb/remote_pb"
"github.com/seaweedfs/seaweedfs/weed/remote_storage"
"github.com/seaweedfs/seaweedfs/weed/replication/source"
"github.com/seaweedfs/seaweedfs/weed/util"
"google.golang.org/grpc"
"google.golang.org/protobuf/proto"
)
func followUpdatesAndUploadToRemote(option *RemoteSyncOptions, filerSource *source.FilerSource, mountedDir string) error {
// read filer remote storage mount mappings
_, _, remoteStorageMountLocation, remoteStorage, detectErr := filer.DetectMountInfo(option.grpcDialOption, pb.ServerAddress(*option.filerAddress), mountedDir)
if detectErr != nil {
return fmt.Errorf("read mount info: %w", detectErr)
}
eachEntryFunc, err := option.makeEventProcessor(remoteStorage, mountedDir, remoteStorageMountLocation, filerSource)
if err != nil {
return err
}
lastOffsetTs := collectLastSyncOffset(option, option.grpcDialOption, pb.ServerAddress(*option.filerAddress), mountedDir, *option.timeAgo)
processor := NewMetadataProcessor(eachEntryFunc, 128, lastOffsetTs.UnixNano())
var lastLogTsNs = time.Now().UnixNano()
processEventFnWithOffset := pb.AddOffsetFunc(func(resp *filer_pb.SubscribeMetadataResponse) error {
if resp.EventNotification.NewEntry != nil {
if *option.storageClass == "" {
delete(resp.EventNotification.NewEntry.Extended, s3_constants.AmzStorageClass)
} else {
resp.EventNotification.NewEntry.Extended[s3_constants.AmzStorageClass] = []byte(*option.storageClass)
}
}
processor.AddSyncJob(resp)
return nil
}, 3*time.Second, func(counter int64, lastTsNs int64) error {
offsetTsNs := processor.processedTsWatermark.Load()
if offsetTsNs == 0 {
return nil
}
// use processor.processedTsWatermark instead of the lastTsNs from the most recent job
now := time.Now().UnixNano()
glog.V(0).Infof("remote sync %s progressed to %v %0.2f/sec", *option.filerAddress, time.Unix(0, offsetTsNs), float64(counter)/(float64(now-lastLogTsNs)/1e9))
lastLogTsNs = now
return remote_storage.SetSyncOffset(option.grpcDialOption, pb.ServerAddress(*option.filerAddress), mountedDir, offsetTsNs)
})
option.clientEpoch++
prefix := mountedDir
if !strings.HasSuffix(prefix, "/") {
prefix = prefix + "/"
}
metadataFollowOption := &pb.MetadataFollowOption{
ClientName: "filer.remote.sync",
ClientId: option.clientId,
ClientEpoch: option.clientEpoch,
SelfSignature: 0,
PathPrefix: prefix,
AdditionalPathPrefixes: []string{filer.DirectoryEtcRemote},
DirectoriesToWatch: nil,
StartTsNs: lastOffsetTs.UnixNano(),
StopTsNs: 0,
EventErrorType: pb.RetryForeverOnError,
}
return pb.FollowMetadata(pb.ServerAddress(*option.filerAddress), option.grpcDialOption, metadataFollowOption, processEventFnWithOffset)
}
func (option *RemoteSyncOptions) makeEventProcessor(remoteStorage *remote_pb.RemoteConf, mountedDir string, remoteStorageMountLocation *remote_pb.RemoteStorageLocation, filerSource *source.FilerSource) (pb.ProcessMetadataFunc, error) {
client, err := remote_storage.GetRemoteStorage(remoteStorage)
if err != nil {
return nil, err
}
handleEtcRemoteChanges := func(resp *filer_pb.SubscribeMetadataResponse) error {
message := resp.EventNotification
if metadataEventUpdatesDirectory(resp, filer.DirectoryEtcRemote) {
if message.NewEntry.Name == filer.REMOTE_STORAGE_MOUNT_FILE {
mappings, readErr := filer.UnmarshalRemoteStorageMappings(message.NewEntry.Content)
if readErr != nil {
return fmt.Errorf("unmarshal mappings: %w", readErr)
}
if remoteLoc, found := mappings.Mappings[mountedDir]; found {
if remoteStorageMountLocation.Bucket != remoteLoc.Bucket || remoteStorageMountLocation.Path != remoteLoc.Path {
glog.Fatalf("Unexpected mount changes %+v => %+v", remoteStorageMountLocation, remoteLoc)
}
} else {
glog.V(0).Infof("unmounted %s exiting ...", mountedDir)
os.Exit(0)
}
}
if message.NewEntry.Name == remoteStorage.Name+filer.REMOTE_STORAGE_CONF_SUFFIX {
conf := &remote_pb.RemoteConf{}
if err := proto.Unmarshal(message.NewEntry.Content, conf); err != nil {
return fmt.Errorf("unmarshal %s/%s: %v", filer.DirectoryEtcRemote, message.NewEntry.Name, err)
}
remoteStorage = conf
if newClient, err := remote_storage.GetRemoteStorage(remoteStorage); err == nil {
client = newClient
} else {
return err
}
}
}
if metadataEventRemovesFromDirectory(resp, filer.DirectoryEtcRemote) &&
message.OldEntry.Name == filer.REMOTE_STORAGE_MOUNT_FILE {
glog.V(0).Infof("unmounted %s exiting ...", mountedDir)
os.Exit(0)
}
return nil
}
eachEntryFunc := func(resp *filer_pb.SubscribeMetadataResponse) error {
message := resp.EventNotification
sourceInEtcRemote, targetInEtcRemote := metadataEventDirectoryMembership(resp, filer.DirectoryEtcRemote)
if sourceInEtcRemote || targetInEtcRemote {
return handleEtcRemoteChanges(resp)
}
if filer_pb.IsEmpty(resp) {
return nil
}
if filer_pb.IsCreate(resp) {
if isMultipartUploadFile(message.NewParentPath, message.NewEntry.Name) {
return nil
}
// Propagate delete markers as deletions on the remote.
// Delete markers are zero-content version entries, so they
// would be filtered out by the HasData check below.
if isDeleteMarker(message.NewEntry) {
if newParent, newName, ok := rewriteVersionedSourcePath(message.NewParentPath, message.NewEntry.Name); ok {
dest := toRemoteStorageLocation(util.FullPath(mountedDir), util.NewFullPath(newParent, newName), remoteStorageMountLocation)
return syncDeleteMarker(client, option, message, dest)
}
return nil
}
if !filer.HasData(message.NewEntry) {
return nil
}
glog.V(2).Infof("create: %+v", resp)
if !shouldSendToRemote(message.NewEntry) {
glog.V(2).Infof("skipping creating: %+v", resp)
return nil
}
// Rewrite internal versioning paths to the original S3 key
// to prevent double-versioning when central also has versioning enabled
parentPath, entryName := message.NewParentPath, message.NewEntry.Name
isRewrittenVersion := false
if newParent, newName, ok := rewriteVersionedSourcePath(parentPath, entryName); ok {
glog.V(0).Infof("rewrite versioned path %s/%s -> %s/%s", parentPath, entryName, newParent, newName)
parentPath, entryName = newParent, newName
isRewrittenVersion = true
}
dest := toRemoteStorageLocation(util.FullPath(mountedDir), util.NewFullPath(parentPath, entryName), remoteStorageMountLocation)
if message.NewEntry.IsDirectory {
glog.V(0).Infof("mkdir %s", remote_storage.FormatLocation(dest))
return client.WriteDirectory(dest, message.NewEntry)
}
glog.V(0).Infof("create %s", remote_storage.FormatLocation(dest))
remoteEntry, writeErr := retriedWriteFile(client, filerSource, message.NewParentPath, message.NewEntry, dest)
if errors.Is(writeErr, errSuperseded) {
glog.Errorf("skipping %s: %v", remote_storage.FormatLocation(dest), writeErr)
return nil
}
if writeErr != nil {
return writeErr
}
// Skip updateLocalEntry for versioned rewrites: the logical
// object (e.g. file.xml) has no filer entry in versioned
// buckets, and stamping the internal v_* entry with a
// RemoteEntry for the logical key is semantically wrong.
// Replay is safe because S3 PutObject is idempotent.
if isRewrittenVersion {
return nil
}
return updateLocalEntry(option, message.NewParentPath, message.NewEntry, remoteEntry)
}
if filer_pb.IsDelete(resp) {
// Skip deletion of internal version files; individual version
// deletes should not propagate to the remote object
if isVersionedPath(resp.Directory, message.OldEntry.Name, message.OldEntry.IsDirectory) {
glog.V(2).Infof("skipping delete of internal version path: %s/%s", resp.Directory, message.OldEntry.Name)
return nil
}
glog.V(2).Infof("delete: %+v", resp)
dest := toRemoteStorageLocation(util.FullPath(mountedDir), util.NewFullPath(resp.Directory, message.OldEntry.Name), remoteStorageMountLocation)
if message.OldEntry.IsDirectory {
glog.V(0).Infof("rmdir %s", remote_storage.FormatLocation(dest))
return client.RemoveDirectory(dest)
}
glog.V(0).Infof("delete %s", remote_storage.FormatLocation(dest))
return client.DeleteFile(dest)
}
if message.OldEntry != nil && message.NewEntry != nil {
return processUpdateEvent(option, filerSource, client, mountedDir, remoteStorageMountLocation, resp)
}
return nil
}
return eachEntryFunc, nil
}
func processUpdateEvent(
filerClient filer_pb.FilerClient,
filerSource filer_pb.FilerClient,
client remote_storage.RemoteStorageClient,
mountedDir string,
remoteStorageMountLocation *remote_pb.RemoteStorageLocation,
resp *filer_pb.SubscribeMetadataResponse,
) error {
message := resp.EventNotification
if isMultipartUploadFile(message.NewParentPath, message.NewEntry.Name) {
return nil
}
if isVersionedPath(message.NewParentPath, message.NewEntry.Name, message.NewEntry.IsDirectory) {
glog.V(2).Infof("skipping update of internal version path: %s/%s", message.NewParentPath, message.NewEntry.Name)
return nil
}
oldDest := toRemoteStorageLocation(util.FullPath(mountedDir), util.NewFullPath(resp.Directory, message.OldEntry.Name), remoteStorageMountLocation)
dest := toRemoteStorageLocation(util.FullPath(mountedDir), util.NewFullPath(message.NewParentPath, message.NewEntry.Name), remoteStorageMountLocation)
if proto.Equal(oldDest, dest) && !shouldSendToRemote(message.NewEntry) {
glog.V(2).Infof("skipping updating: %+v", resp)
return nil
}
if message.NewEntry.IsDirectory {
return client.WriteDirectory(dest, message.NewEntry)
}
if isMetadataOnlyUpdate(resp.Directory, message) {
remoteEntry, err := liveRemoteEntry(filerClient, message.NewParentPath, message.NewEntry)
if errors.Is(err, filer_pb.ErrNotFound) {
glog.V(2).Infof("skipping updating deleted entry: %+v", resp)
return nil
}
if err != nil {
return err
}
if remoteEntry != nil {
glog.V(2).Infof("update meta: %+v", resp)
return client.UpdateFileMetadata(dest, message.OldEntry, message.NewEntry)
}
glog.V(0).Infof("never replicated, uploading %s", remote_storage.FormatLocation(dest))
}
if !proto.Equal(oldDest, dest) && !filer.HasData(message.NewEntry) && message.NewEntry.IsInRemoteOnly() {
glog.V(0).Infof("skip uploading renamed remote-only entry %s: content is only on the deleted remote object", remote_storage.FormatLocation(dest))
return nil
}
glog.V(2).Infof("update: %+v", resp)
if !proto.Equal(oldDest, dest) {
glog.V(0).Infof("delete %s", remote_storage.FormatLocation(oldDest))
if err := client.DeleteFile(oldDest); err != nil {
if isMultipartUploadFile(resp.Directory, message.OldEntry.Name) {
return nil
}
if !errors.Is(err, remote_storage.ErrRemoteObjectNotFound) {
return err
}
}
}
remoteEntry, writeErr := retriedWriteFile(client, filerSource, message.NewParentPath, message.NewEntry, dest)
if errors.Is(writeErr, errSuperseded) {
glog.Errorf("skipping %s: %v", remote_storage.FormatLocation(dest), writeErr)
return nil
}
if writeErr != nil {
return writeErr
}
return updateLocalEntry(filerClient, message.NewParentPath, message.NewEntry, remoteEntry)
}
// isSuperseded reports whether the filer has moved past the entry an event
// described: it is deleted, or it no longer references every chunk the event
// named. Those are the chunks the filer deletes when an entry is updated, so
// they are gone from the volume servers, or about to be, and no retry of the
// upload can succeed. Chunks are compared by file id, not content: a rewrite
// stores even identical bytes under new ids and drops the old ones. A replay
// from an earlier offset (-timeAgo) re-emits such events. Failing one holds the
// sync offset before it, so every restart of the subscription replays it into
// the same dead chunks, and progress on everything after it in the log is never
// persisted. Skipping is safe: the event that superseded this one follows in
// the log, and the delete removes the remote object or the rewrite uploads the
// current content. A lookup that fails for any other reason keeps the write
// failure, so the event is retried.
func isSuperseded(filerClient filer_pb.FilerClient, dir string, entry *filer_pb.Entry) bool {
current, _, _, err := filer_pb.GetEntry(context.Background(), filerClient, util.NewFullPath(dir, entry.Name))
if errors.Is(err, filer_pb.ErrNotFound) {
return true
}
if err != nil {
return false
}
if len(entry.Content) > 0 || len(current.Content) > 0 {
return !bytes.Equal(entry.Content, current.Content)
}
return len(filer.DoMinusChunks(entry.GetChunks(), current.GetChunks())) > 0
}
// errSuperseded marks an upload that failed for an entry the filer has since
// moved past (isSuperseded). The caller skips the event instead of failing it.
var errSuperseded = errors.New("deleted or rewritten since the event was logged")
// retriedWriteFile uploads the entry, retrying transient failures. Every failed
// attempt first asks the filer whether the entry is superseded, and stops at
// once when it is: a dead chunk reads as a transient "RequestError" from the
// SDK, and waiting out the backoff on it buys nothing.
func retriedWriteFile(client remote_storage.RemoteStorageClient, filerSource filer_pb.FilerClient, dir string, newEntry *filer_pb.Entry, dest *remote_pb.RemoteStorageLocation) (remoteEntry *filer_pb.RemoteEntry, err error) {
err = util.RetryOnError("writeFile", func(err error) bool {
return !errors.Is(err, errSuperseded) && util.IsTransientError(err)
}, func() error {
reader := filer.NewFileReader(filerSource, newEntry)
glog.V(0).Infof("create %s", remote_storage.FormatLocation(dest))
var writeErr error
remoteEntry, writeErr = client.WriteFile(dest, newEntry, reader)
if writeErr != nil && isSuperseded(filerSource, dir, newEntry) {
return fmt.Errorf("%s %w: %w", util.NewFullPath(dir, newEntry.Name), errSuperseded, writeErr)
}
return writeErr
})
if err != nil && !errors.Is(err, errSuperseded) {
glog.Errorf("write to %s: %v", dest, err)
}
return
}
func collectLastSyncOffset(filerClient filer_pb.FilerClient, grpcDialOption grpc.DialOption, filerAddress pb.ServerAddress, mountedDir string, timeAgo time.Duration) time.Time {
// 1. specified by timeAgo
// 2. last offset timestamp for this directory
// 3. directory creation time
var lastOffsetTs time.Time
if timeAgo == 0 {
mountedDirEntry, _, _, err := filer_pb.GetEntry(context.Background(), filerClient, util.FullPath(mountedDir))
if err != nil {
glog.V(0).Infof("get mounted directory %s: %v", mountedDir, err)
return time.Now()
}
lastOffsetTsNs, err := remote_storage.GetSyncOffset(grpcDialOption, filerAddress, mountedDir)
if mountedDirEntry != nil {
if err == nil && mountedDirEntry.Attributes.Crtime < lastOffsetTsNs/1000000 {
lastOffsetTs = time.Unix(0, lastOffsetTsNs)
glog.V(0).Infof("resume from %v", lastOffsetTs)
} else {
lastOffsetTs = time.Unix(mountedDirEntry.Attributes.Crtime, 0)
}
} else {
lastOffsetTs = time.Now()
}
} else {
lastOffsetTs = time.Now().Add(-timeAgo)
}
return lastOffsetTs
}
func toRemoteStorageLocation(mountDir, sourcePath util.FullPath, remoteMountLocation *remote_pb.RemoteStorageLocation) *remote_pb.RemoteStorageLocation {
source := string(sourcePath[len(mountDir):])
dest := util.FullPath(remoteMountLocation.Path).Child(source)
return &remote_pb.RemoteStorageLocation{
Name: remoteMountLocation.Name,
Bucket: remoteMountLocation.Bucket,
Path: string(dest),
}
}
// isMetadataOnlyUpdate reports whether an update leaves the entry at the same
// path with the same content, so the remote object needs at most its metadata
// rewritten -- provided it is already there, which liveRemoteEntry establishes.
func isMetadataOnlyUpdate(dir string, message *filer_pb.EventNotification) bool {
if dir != message.NewParentPath || message.OldEntry.Name != message.NewEntry.Name {
return false
}
return filer.IsSameData(message.OldEntry, message.NewEntry)
}
// liveRemoteEntry returns the RemoteEntry showing the entry's object is on the
// remote, or nil when it never got there. The event's own is not enough: a
// chmod right after a write is logged before the sync has uploaded the write
// and stamped the entry, and treating it as unreplicated would upload twice.
// Returns filer_pb.ErrNotFound when the entry has since been deleted.
func liveRemoteEntry(filerClient filer_pb.FilerClient, dir string, entry *filer_pb.Entry) (*filer_pb.RemoteEntry, error) {
if entry.RemoteEntry != nil {
return entry.RemoteEntry, nil
}
current, _, _, err := filer_pb.GetEntry(context.Background(), filerClient, util.NewFullPath(dir, entry.Name))
if err != nil {
return nil, err
}
return current.RemoteEntry, nil
}
func shouldSendToRemote(entry *filer_pb.Entry) bool {
if entry.RemoteEntry == nil {
return true
}
if entry.RemoteEntry.RemoteMtime < entry.Attributes.Mtime {
return true
}
return false
}
func updateLocalEntry(filerClient filer_pb.FilerClient, dir string, entry *filer_pb.Entry, remoteEntry *filer_pb.RemoteEntry) error {
remoteEntry.LastLocalSyncTsNs = time.Now().UnixNano()
entry.RemoteEntry = remoteEntry
return filerClient.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
_, err := client.UpdateEntry(context.Background(), &filer_pb.UpdateEntryRequest{
Directory: dir,
Entry: entry,
})
return err
})
}
func isMultipartUploadFile(dir string, name string) bool {
return isMultipartUploadDir(dir) && strings.HasSuffix(name, ".part")
}
func isMultipartUploadDir(dir string) bool {
return strings.HasPrefix(dir, "/buckets/") &&
strings.Contains(dir, "/"+s3_constants.MultipartUploadsFolder+"/")
}
// isDeleteMarker returns true if the entry is an S3 delete marker
// (a zero-content version entry with ExtDeleteMarkerKey set to "true").
func isDeleteMarker(entry *filer_pb.Entry) bool {
if entry == nil || entry.Extended == nil {
return false
}
return string(entry.Extended[s3_constants.ExtDeleteMarkerKey]) == "true"
}
// syncDeleteMarker propagates a delete marker to the remote storage and
// persists a local sync marker so that replaying the same event is a no-op.
func syncDeleteMarker(
client remote_storage.RemoteStorageClient,
filerClient filer_pb.FilerClient,
message *filer_pb.EventNotification,
dest *remote_pb.RemoteStorageLocation,
) error {
glog.V(0).Infof("delete (marker) %s", remote_storage.FormatLocation(dest))
if err := client.DeleteFile(dest); err != nil {
return err
}
return updateLocalEntry(filerClient, message.NewParentPath, message.NewEntry, &filer_pb.RemoteEntry{
StorageName: dest.Name,
RemoteMtime: message.NewEntry.Attributes.GetMtime(),
})
}
// isVersionedPath returns true if the dir/name refers to an internal
// versioning path (.versions directory or a version file inside it).
// These paths are SeaweedFS-internal and must not be synced to remote
// storage as-is, because the remote S3 endpoint may apply its own
// versioning, leading to double-versioned paths.
//
// For directories: matches only when the entry name ends with the
// VersionsFolder suffix (e.g. "file.xml.versions").
// For files: matches only when the parent directory ends with
// VersionsFolder and the file name has the "v_" prefix used by
// the internal version file naming convention.
func isVersionedPath(dir string, name string, isDir bool) bool {
if !strings.HasPrefix(dir, "/buckets/") {
return false
}
if isDir {
return strings.HasSuffix(name, s3_constants.VersionsFolder)
}
return strings.HasSuffix(dir, s3_constants.VersionsFolder) && strings.HasPrefix(name, "v_")
}
// rewriteVersionedSourcePath rewrites an internal versioning path to the
// original S3 object key. When a file is uploaded to a versioned bucket,
// SeaweedFS stores it internally as:
//
// /buckets/{bucket}/{key}.versions/v_{versionId}
//
// This function strips the ".versions/v_{versionId}" suffix and returns
// the original parent directory and object name, so the remote destination
// points to the logical S3 key rather than the internal version storage path.
//
// Returns (newDir, newName, true) if the path was rewritten, or
// (dir, name, false) if the path is not a versioned path.
func rewriteVersionedSourcePath(dir string, name string) (string, string, bool) {
if !strings.HasPrefix(dir, "/buckets/") {
return dir, name, false
}
if !strings.HasSuffix(dir, s3_constants.VersionsFolder) {
return dir, name, false
}
if !strings.HasPrefix(name, "v_") {
return dir, name, false
}
// dir = "/buckets/bucket/path/to/file.xml.versions"
// name = "v_abc123"
// Original object: dir without ".versions" suffix → "/buckets/bucket/path/to/file.xml"
originalObjectPath := dir[:len(dir)-len(s3_constants.VersionsFolder)]
lastSlash := strings.LastIndex(originalObjectPath, "/")
if lastSlash < 0 {
return dir, name, false
}
newDir := originalObjectPath[:lastSlash]
if lastSlash == 0 {
newDir = "/"
}
return newDir, originalObjectPath[lastSlash+1:], true
}