seaweedfs/weed/filer/filer.go

package filer

import (
	"context"
	"errors"
	"fmt"
	"os"
	"sort"
	"strings"
	"sync/atomic"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/remote_storage"
	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
	"github.com/seaweedfs/seaweedfs/weed/s3api/s3bucket"

	"github.com/seaweedfs/seaweedfs/weed/cluster/lock_manager"
	"github.com/seaweedfs/seaweedfs/weed/filer/empty_folder_cleanup"

	"github.com/seaweedfs/seaweedfs/weed/cluster"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
	"github.com/seaweedfs/seaweedfs/weed/pb/remote_pb"

	"google.golang.org/grpc"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/stats"
	"github.com/seaweedfs/seaweedfs/weed/util"
	"github.com/seaweedfs/seaweedfs/weed/util/log_buffer"
	"github.com/seaweedfs/seaweedfs/weed/wdclient"
	"golang.org/x/sync/singleflight"
)

const (
	LogFlushInterval = time.Minute
	PaginationSize   = 1024
	FilerStoreId     = "filer.store.id"
)

var (
	OS_UID = uint32(os.Getuid())
	OS_GID = uint32(os.Getgid())
)

type Filer struct {
	UniqueFilerId                 int32
	UniqueFilerEpoch              int32
	Store                         VirtualFilerStore
	MasterClient                  *wdclient.MasterClient
	FileIdDeletionQueue           *util.UnboundedQueue
	GrpcDialOption                grpc.DialOption
	DirBucketsPath                string
	Cipher                        bool
	LocalMetaLogBuffer            *log_buffer.LogBuffer
	metaLogCollection             string
	metaLogReplication            string
	DefaultDiskType               string
	MetaAggregator                *MetaAggregator
	Signature                     int32
	FilerConf                     *FilerConf
	placementOverlay              PlacementOverlay
	RemoteStorage                 *FilerRemoteStorage
	BuildGuardedRemoteClient      RemoteStorageClientBuilder
	AllowUntrustedRemoteEndpoints bool
	lazyFetchGroup                singleflight.Group
	lazyListGroup                 singleflight.Group
	Dlm                           *lock_manager.DistributedLockManager
	MaxFilenameLength             uint32
	deletionQuit                  chan struct{}
	DeletionRetryQueue            *DeletionRetryQueue
	EmptyFolderCleaner            *empty_folder_cleanup.EmptyFolderCleaner
	EmptyFolderCleanupDelay       time.Duration
	persistedLogCache             *persistedLogCache
	metaLogInflight               metaLogInflight
	remoteTombstones              *remoteDeletionTombstones
	// remoteTombstonesDone, when non-nil, is closed once the startup tombstone
	// rebuild finishes; lazy remote reads wait on it so a pending delete
	// cannot resurrect in the gap.
	remoteTombstonesDone atomic.Pointer[chan struct{}]
}

func NewFiler(masters pb.ServerDiscovery, grpcDialOption grpc.DialOption, filerHost pb.ServerAddress, filerGroup string, collection string, replication string, dataCenter string, maxFilenameLength uint32, notifyFn func()) *Filer {
	f := &Filer{
		MasterClient:        wdclient.NewMasterClient(grpcDialOption, filerGroup, cluster.FilerType, filerHost, dataCenter, "", masters),
		FileIdDeletionQueue: util.NewUnboundedQueue(),
		GrpcDialOption:      grpcDialOption,
		FilerConf:           NewFilerConf(),
		RemoteStorage:       NewFilerRemoteStorage(),
		UniqueFilerId:       util.RandomInt32(),
		Dlm:                 lock_manager.NewDistributedLockManager(filerHost),
		MaxFilenameLength:   maxFilenameLength,
		deletionQuit:        make(chan struct{}),
		DeletionRetryQueue:  NewDeletionRetryQueue(),
		persistedLogCache:   newPersistedLogCache(persistedLogCacheMaxBytes),
		remoteTombstones:    newRemoteDeletionTombstones(),
	}
	if f.UniqueFilerId < 0 {
		f.UniqueFilerId = -f.UniqueFilerId
	}

	// ReadFromDiskFn is intentionally nil here.  SubscribeLocalMetadata already
	// manages disk reads explicitly with shouldReadFromDisk / lastCheckedFlushTsNs
	// tracking.  Setting ReadFromDiskFn would cause LoopProcessLogData to issue a
	// redundant ReadPersistedLogBuffer call (ListDirectoryEntries + readahead
	// goroutine) on every 250ms health-check tick when a subscriber encounters
	// ResumeFromDiskError, adding significant CPU and GC pressure even when idle.
	f.LocalMetaLogBuffer = log_buffer.NewLogBuffer("local", LogFlushInterval, f.logFlushFunc, nil, notifyFn)
	f.metaLogCollection = collection
	f.metaLogReplication = replication

	if newPlacementOverlay != nil {
		f.placementOverlay = newPlacementOverlay(f)
	}

	go f.loopProcessingDeletion()

	return f
}

func (f *Filer) buildRemoteStorageClient(ctx context.Context, remoteConf *remote_pb.RemoteConf) (remote_storage.RemoteStorageClient, error) {
	if f.BuildGuardedRemoteClient != nil {
		return f.BuildGuardedRemoteClient(ctx, remoteConf, f.AllowUntrustedRemoteEndpoints)
	}
	return remote_storage.GetRemoteStorage(remoteConf)
}

func (f *Filer) MaybeBootstrapFromOnePeer(self pb.ServerAddress, existingNodes []*master_pb.ClusterNodeUpdate, snapshotTime time.Time) (err error) {
	if len(existingNodes) == 0 {
		return
	}
	sort.Slice(existingNodes, func(i, j int) bool {
		return existingNodes[i].CreatedAtNs < existingNodes[j].CreatedAtNs
	})
	earliestNode := existingNodes[0]
	if pb.ServerAddress(earliestNode.Address).Equals(self) {
		return
	}

	glog.V(0).Infof("bootstrap from %v clientId:%d", earliestNode.Address, f.UniqueFilerId)

	return pb.WithFilerClient(false, f.UniqueFilerId, pb.ServerAddress(earliestNode.Address), f.GrpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
		return filer_pb.StreamBfs(client, "/", snapshotTime.UnixNano(), func(parentPath util.FullPath, entry *filer_pb.Entry) error {
			return f.Store.InsertEntry(context.Background(), FromPbEntry(string(parentPath), entry))
		})
	})

}

func (f *Filer) AggregateFromPeers(self pb.ServerAddress, existingNodes []*master_pb.ClusterNodeUpdate, startFrom time.Time) {

	var snapshot []pb.ServerAddress
	for _, node := range existingNodes {
		address := pb.ServerAddress(node.Address)
		snapshot = append(snapshot, address)
	}
	f.Dlm.LockRing.SetSnapshot(snapshot, 0)
	glog.V(0).Infof("%s aggregate from peers %+v", self, snapshot)

	// Initialize the empty folder cleaner using the same LockRing as Dlm for consistent hashing
	f.EmptyFolderCleaner = empty_folder_cleanup.NewEmptyFolderCleaner(f, f.Dlm.LockRing, self, f.DirBucketsPath, f.EmptyFolderCleanupDelay)

	f.MetaAggregator = NewMetaAggregator(f, self, f.GrpcDialOption)
	// The ring starts empty while peer history sits on disk: mark the pre-startFrom
	// range evicted so a cursor there reads disk, not the ring's earliest entry.
	f.MetaAggregator.MetaLogBuffer.MarkEvictedThrough(startFrom.UnixNano())
	f.MasterClient.SetOnPeerUpdateFn(func(update *master_pb.ClusterNodeUpdate, startFrom time.Time) {
		if update.NodeType != cluster.FilerType {
			return
		}
		// Lock ring is now managed by the master via LockRingUpdate,
		// so we no longer call AddServer/RemoveServer here.
		f.MetaAggregator.OnPeerUpdate(update, startFrom)
	})
	f.MasterClient.SetOnLockRingUpdateFn(func(update *master_pb.LockRingUpdate) {
		var servers []pb.ServerAddress
		for _, s := range update.Servers {
			servers = append(servers, pb.ServerAddress(s))
		}
		glog.V(0).Infof("LockRing: applying master ring update v%d: %v", update.Version, servers)
		f.Dlm.LockRing.SetSnapshot(servers, update.Version)
	})
	f.MasterClient.SetOnMasterChangeFn(func(previous, current pb.ServerAddress) {
		glog.V(0).Infof("LockRing: master changed %s -> %s, resetting ring", previous, current)
		f.Dlm.LockRing.Reset()
	})

	// Subscribe to the local filer first: its events reach the aggregated
	// buffer only through this subscription, and the peer watermarks must
	// account for it before any remote peer - a remotes-only watermark set
	// would claim completeness without self. existingNodes can omit self
	// (master registration races this bootstrap); duplicate adds are no-ops.
	f.MetaAggregator.OnPeerUpdate(&master_pb.ClusterNodeUpdate{
		NodeType: cluster.FilerType,
		Address:  string(self),
		IsAdd:    true,
	}, startFrom)
	for _, peerUpdate := range existingNodes {
		f.MetaAggregator.OnPeerUpdate(peerUpdate, startFrom)
	}

}

func (f *Filer) ListExistingPeerUpdates(ctx context.Context) (existingNodes []*master_pb.ClusterNodeUpdate) {
	return cluster.ListExistingPeerUpdates(f.GetMaster(ctx), f.GrpcDialOption, f.MasterClient.FilerGroup, cluster.FilerType)
}

func (f *Filer) SetStore(store FilerStore) (isFresh bool) {
	f.Store = NewFilerStoreWrapper(store)

	return f.setOrLoadFilerStoreSignature(store)
}

func (f *Filer) setOrLoadFilerStoreSignature(store FilerStore) (isFresh bool) {
	storeIdBytes, err := store.KvGet(context.Background(), []byte(FilerStoreId))
	if err == ErrKvNotFound || err == nil && len(storeIdBytes) == 0 {
		f.Signature = util.RandomInt32()
		storeIdBytes = make([]byte, 4)
		util.Uint32toBytes(storeIdBytes, uint32(f.Signature))
		if err = store.KvPut(context.Background(), []byte(FilerStoreId), storeIdBytes); err != nil {
			glog.Fatalf("set %s=%d : %v", FilerStoreId, f.Signature, err)
		}
		glog.V(0).Infof("create %s to %d", FilerStoreId, f.Signature)
		return true
	} else if err == nil && len(storeIdBytes) == 4 {
		f.Signature = int32(util.BytesToUint32(storeIdBytes))
		glog.V(0).Infof("existing %s = %d", FilerStoreId, f.Signature)
	} else {
		glog.Fatalf("read %v=%v : %v", FilerStoreId, string(storeIdBytes), err)
	}
	return false
}

func (f *Filer) GetStore() (store FilerStore) {
	return f.Store
}

func (fs *Filer) GetMaster(ctx context.Context) pb.ServerAddress {
	return fs.MasterClient.GetMaster(ctx)
}

func (f *Filer) BeginTransaction(ctx context.Context) (context.Context, error) {
	return f.Store.BeginTransaction(ctx)
}

func (f *Filer) CommitTransaction(ctx context.Context) error {
	return f.Store.CommitTransaction(ctx)
}

func (f *Filer) RollbackTransaction(ctx context.Context) error {
	return f.Store.RollbackTransaction(ctx)
}

// CreateEntry creates or replaces an entry. When existing is non-nil the caller
// has already fetched the current entry at this path under a path lock, and it
// is reused instead of looking the store up again; pass nil to have CreateEntry
// look it up itself.
func (f *Filer) CreateEntry(ctx context.Context, entry *Entry, existing *Entry, o_excl bool, isFromOtherCluster bool, signatures []int32, skipCreateParentDir bool, maxFilenameLength uint32) error {

	if string(entry.FullPath) == "/" {
		return nil
	}

	if entry.FullPath.IsLongerFileName(maxFilenameLength) {
		return filer_pb.ErrEntryNameTooLong
	}

	if entry.IsDirectory() {
		entry.Attr.TtlSec = 0
	}

	if entry.Attr.Atime.IsZero() {
		entry.Attr.Atime = entryInitialAtime(entry.Attr)
	}

	oldEntry := existing
	if oldEntry == nil {
		var findErr error
		oldEntry, findErr = f.FindEntry(ctx, entry.FullPath)
		if o_excl && findErr != nil && !errors.Is(findErr, filer_pb.ErrNotFound) {
			// An exclusive create cannot decide whether the path exists when
			// the lookup itself failed; proceeding would upsert over it.
			return fmt.Errorf("find entry %s: %w", entry.FullPath, findErr)
		}
	}

	/*
		if !hasWritePermission(lastDirectoryEntry, entry) {
			glog.V(0).Infof("directory %s: %v, entry: uid=%d gid=%d",
				lastDirectoryEntry.FullPath, lastDirectoryEntry.Attr, entry.Uid, entry.Gid)
			return fmt.Errorf("no write permission in folder %v", lastDirectoryEntry.FullPath)
		}
	*/

	if oldEntry == nil {
		f.ensureEntryInode(entry)

		glog.V(4).InfofCtx(ctx, "InsertEntry %s: new entry: %v", entry.FullPath, entry.Name())
		if err := f.Store.InsertEntry(ctx, entry); err != nil {
			glog.ErrorfCtx(ctx, "insert entry %s: %v", entry.FullPath, err)
			return fmt.Errorf("insert entry %s: %v", entry.FullPath, err)
		}

		// Parents go after the entry: one checked first can be taken by the
		// empty-folder cleaner before the entry lands, and nothing would look again.
		if !skipCreateParentDir {
			dirParts := strings.Split(string(entry.FullPath), "/")
			if err := f.ensureParentDirectoryEntry(ctx, entry, dirParts, len(dirParts)-1, isFromOtherCluster); err != nil {
				// The entry stays: deleting by path would destroy a concurrent create
				// that already succeeded through the update branch, and the update keeps
				// the inode and crtime while mtime only survives the store to the second.
				// It is not announced - the aggregator replicates creates into peer
				// stores, so a failed write would land on all of them rather than on the
				// one filer whose next write into that folder repairs it.
				glog.ErrorfCtx(ctx, "create parent directories of %s: %v", entry.FullPath, err)
				return err
			}
		}

		if !entry.IsDirectory() {
			stats.FilerObjectSizeBytesHistogram.Observe(float64(entry.Size()))
		}
	} else {
		if o_excl {
			glog.V(3).InfofCtx(ctx, "EEXIST: entry %s already exists", entry.FullPath)
			return fmt.Errorf("%s: %w", entry.FullPath, filer_pb.ErrEntryAlreadyExists)
		}
		glog.V(4).InfofCtx(ctx, "UpdateEntry %s: old entry: %v", entry.FullPath, oldEntry.Name())
		if err := f.UpdateEntry(ctx, oldEntry, entry); err != nil {
			if errors.Is(err, filer_pb.ErrExistingIsDirectory) || errors.Is(err, filer_pb.ErrExistingIsFile) {
				glog.V(2).InfofCtx(ctx, "update entry %s: %v", entry.FullPath, err)
			} else {
				glog.ErrorfCtx(ctx, "update entry %s: %v", entry.FullPath, err)
			}
			return fmt.Errorf("update entry %s: %w", entry.FullPath, err)
		}
	}

	f.NotifyUpdateEvent(ctx, oldEntry, entry, true, isFromOtherCluster, signatures)

	f.deleteChunksIfNotNew(ctx, oldEntry, entry)

	glog.V(4).InfofCtx(ctx, "CreateEntry %s: created", entry.FullPath)

	return nil
}

func (f *Filer) ensureParentDirectoryEntry(ctx context.Context, entry *Entry, dirParts []string, level int, isFromOtherCluster bool) (err error) {

	if level == 0 {
		return nil
	}

	dirPath := "/" + util.Join(dirParts[:level]...)
	// fmt.Printf("%d dirPath: %+v\n", level, dirPath)

	// check the store directly
	glog.V(4).InfofCtx(ctx, "find uncached directory: %s", dirPath)
	dirEntry, findErr := f.FindEntry(ctx, util.FullPath(dirPath))
	if findErr != nil && !errors.Is(findErr, filer_pb.ErrNotFound) {
		return findErr
	}

	// no such existing directory
	if dirEntry == nil {

		// fmt.Printf("dirParts: %v %v %v\n", dirParts[0], dirParts[1], dirParts[2])
		// dirParts[0] == "" and dirParts[1] == "buckets"
		isUnderBuckets := len(dirParts) >= 3 && dirParts[1] == "buckets"
		if isUnderBuckets {
			if !strings.HasPrefix(dirParts[2], ".") {
				if err := s3bucket.VerifyS3BucketName(dirParts[2]); err != nil {
					return fmt.Errorf("invalid bucket name %s: %v", dirParts[2], err)
				}
			}
		}

		// ensure parent directory
		if err = f.ensureParentDirectoryEntry(ctx, entry, dirParts, level-1, isFromOtherCluster); err != nil {
			return err
		}

		// create the directory
		now := time.Now()

		dirEntry = &Entry{
			FullPath: util.FullPath(dirPath),
			Attr: Attr{
				Mtime:      now,
				Crtime:     now,
				Mode:       os.ModeDir | entry.Mode | 0111,
				Uid:        entry.Uid,
				Gid:        entry.Gid,
				UserName:   entry.UserName,
				GroupNames: entry.GroupNames,
			},
		}
		f.ensureEntryInode(dirEntry)
		if isUnderBuckets && level > 3 {
			// Parent directories under buckets are created automatically; no additional logging.
		}

		glog.V(2).InfofCtx(ctx, "create directory: %s %v", dirPath, dirEntry.Mode)
		mkdirErr := f.Store.InsertEntry(ctx, dirEntry)
		if mkdirErr != nil {
			if fEntry, err := f.FindEntry(ctx, util.FullPath(dirPath)); err == filer_pb.ErrNotFound || fEntry == nil {
				glog.V(3).InfofCtx(ctx, "mkdir %s: %v", dirPath, mkdirErr)
				return fmt.Errorf("mkdir %s: %v", dirPath, mkdirErr)
			}
		} else {
			if !strings.HasPrefix("/"+util.Join(dirParts[:]...), SystemLogDir) {
				f.NotifyUpdateEvent(ctx, nil, dirEntry, false, isFromOtherCluster, nil)
			}
		}

	} else if !dirEntry.IsDirectory() {
		// S3 allows both "foo/bar" (object) and "foo/bar/xyzzy" (another
		// object) to coexist because S3 has a flat key space. Promote the
		// existing file to a directory, preserving its content/chunks so
		// the original object data remains accessible.
		glog.V(2).InfofCtx(ctx, "promoting %s from file to directory for %s", dirPath, entry.FullPath)
		dirEntry.Attr.Mode |= os.ModeDir | 0111
		// Expiring the entry now deletes the directory row and strands the keys under
		// it, so the prefix object gives up its lazy TTL. The lifecycle worker still
		// expires it, through the delete that leaves the directory behind.
		dirEntry.Attr.TtlSec = 0
		// An empty object leaves no chunks, content or mime behind, so without the
		// mark the promotion would hide it.
		if dirEntry.Extended == nil {
			dirEntry.Extended = make(map[string][]byte)
		}
		dirEntry.Extended[s3_constants.SeaweedFSPrefixObject] = []byte("true")
		if updateErr := f.Store.UpdateEntry(ctx, dirEntry); updateErr != nil {
			return fmt.Errorf("promote %s to directory: %v", dirPath, updateErr)
		}
		f.NotifyUpdateEvent(ctx, nil, dirEntry, false, isFromOtherCluster, nil)
	}

	return nil
}

// restorableModeBits is everything but the type bits: ModePerm alone would drop
// setgid, setuid and sticky, quietly changing group inheritance and delete semantics.
const restorableModeBits = os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky

// DirectoryAttributes reads what a directory would need to be recreated as it is.
func (f *Filer) DirectoryAttributes(ctx context.Context, dirPath util.FullPath) (attrs empty_folder_cleanup.DirectoryAttributes, err error) {
	entry, err := f.FindEntry(ctx, dirPath)
	if err != nil {
		return attrs, err
	}
	if entry == nil {
		return attrs, filer_pb.ErrNotFound
	}
	return empty_folder_cleanup.DirectoryAttributes{
		Mode:       entry.Mode & restorableModeBits,
		Uid:        entry.Uid,
		Gid:        entry.Gid,
		UserName:   entry.UserName,
		GroupNames: entry.GroupNames,
	}, nil
}

// EnsureDirectoryEntry recreates dirPath, and any missing ancestor, for entries that
// outlived the directory holding them. dirPath comes back with the attributes it was
// deleted with, so a restore cannot hand back a directory more permissive than the one
// it replaces - including when someone else already put it back with wider ones.
func (f *Filer) EnsureDirectoryEntry(ctx context.Context, dirPath util.FullPath, attrs empty_folder_cleanup.DirectoryAttributes) error {
	existing, err := f.FindEntry(ctx, dirPath)
	if err != nil && !errors.Is(err, filer_pb.ErrNotFound) {
		return err
	}
	if existing != nil {
		// A writer recreating its own missing parent infers the mode from the entry it
		// is inserting, so it can come back wider. Intersect rather than replace, or a
		// mode holding a bit the saved one lacks would be granted the ones it lacks.
		kept := existing.Mode & attrs.Mode & restorableModeBits
		if existing.Mode&restorableModeBits == kept {
			return nil
		}
		narrowed := existing.ShallowClone()
		narrowed.Mode = existing.Mode&^restorableModeBits | kept
		glog.V(1).InfofCtx(ctx, "restore directory %s: narrowing %v to %v", dirPath, existing.Mode, narrowed.Mode)
		if err := f.UpdateEntry(ctx, existing, narrowed); err != nil {
			return err
		}
		f.NotifyUpdateEvent(ctx, existing, narrowed, false, false, nil)
		return nil
	}

	holder := &Entry{FullPath: dirPath, Attr: Attr{
		Mode: attrs.Mode, Uid: attrs.Uid, Gid: attrs.Gid,
		UserName: attrs.UserName, GroupNames: attrs.GroupNames,
	}}
	dirParts := strings.Split(string(dirPath), "/")
	if err := f.ensureParentDirectoryEntry(ctx, holder, dirParts, len(dirParts)-1, false); err != nil {
		return err
	}

	now := time.Now()
	dirEntry := &Entry{FullPath: dirPath, Attr: Attr{
		Mtime: now, Crtime: now,
		Mode:     os.ModeDir | attrs.Mode,
		Uid:      attrs.Uid,
		Gid:      attrs.Gid,
		UserName: attrs.UserName, GroupNames: attrs.GroupNames,
	}}
	f.ensureEntryInode(dirEntry)
	if err := f.Store.InsertEntry(ctx, dirEntry); err != nil {
		return fmt.Errorf("restore directory %s: %v", dirPath, err)
	}
	f.NotifyUpdateEvent(ctx, nil, dirEntry, false, false, nil)

	return nil
}

func (f *Filer) UpdateEntry(ctx context.Context, oldEntry, entry *Entry) (err error) {
	if oldEntry != nil {
		entry.Attr.Crtime = oldEntry.Attr.Crtime
		if oldEntry.Attr.Inode != 0 {
			// Object identity must not change on in-place updates.
			entry.Attr.Inode = oldEntry.Attr.Inode
		} else {
			f.ensureEntryInode(entry)
		}
		// A type conflict is reported through the sentinel, and callers act on it -
		// an S3 write of a key other keys are nested under retries as a prefix object -
		// so it is the caller's outcome that decides whether anything went wrong.
		if oldEntry.IsDirectory() && !entry.IsDirectory() {
			glog.V(2).InfofCtx(ctx, "existing %s is a directory", oldEntry.FullPath)
			return fmt.Errorf("%s: %w", oldEntry.FullPath, filer_pb.ErrExistingIsDirectory)
		}
		if !oldEntry.IsDirectory() && entry.IsDirectory() {
			glog.V(2).InfofCtx(ctx, "existing %s is a file", oldEntry.FullPath)
			return fmt.Errorf("%s: %w", oldEntry.FullPath, filer_pb.ErrExistingIsFile)
		}
	}
	if entry.Attr.Atime.IsZero() {
		entry.Attr.Atime = entryInitialAtime(entry.Attr)
	}
	return f.Store.UpdateEntry(ctx, entry)
}

func entryInitialAtime(attr Attr) time.Time {
	if !attr.Mtime.IsZero() {
		return attr.Mtime
	}
	return attr.Crtime
}

var (
	Root = &Entry{
		FullPath: "/",
		Attr: Attr{
			Mtime:  time.Now(),
			Crtime: time.Now(),
			Mode:   os.ModeDir | 0755,
			Uid:    OS_UID,
			Gid:    OS_GID,
		},
	}
)

func (f *Filer) FindEntry(ctx context.Context, p util.FullPath) (entry *Entry, err error) {

	if string(p) == "/" {
		return Root, nil
	}
	entry, err = f.Store.FindEntry(ctx, p)
	// A directory is deleted here one row at a time, which would strand whatever is
	// under it, so a TTL an older build left on one is not acted on.
	if entry != nil && entry.TtlSec > 0 && !entry.IsDirectory() {
		if entry.IsExpireS3Enabled() {
			if entry.GetS3ExpireTime().Before(time.Now()) && !entry.IsS3Versioning() {
				if delErr := f.doDeleteEntryMetaAndData(ctx, entry, true, false, nil); delErr != nil {
					glog.ErrorfCtx(ctx, "FindEntry doDeleteEntryMetaAndData %s failed: %v", entry.FullPath, delErr)
				}
				return nil, filer_pb.ErrNotFound
			}
		} else if entry.Crtime.Add(time.Duration(entry.TtlSec) * time.Second).Before(time.Now()) {
			f.Store.DeleteOneEntry(ctx, entry)
			return nil, filer_pb.ErrNotFound
		}
	}

	if entry == nil && (err == nil || errors.Is(err, filer_pb.ErrNotFound)) {
		if lazy, lazyErr := f.maybeLazyFetchFromRemote(ctx, p); lazyErr != nil {
			glog.V(1).InfofCtx(ctx, "FindEntry lazy fetch %s: %v", p, lazyErr)
		} else if lazy != nil {
			return lazy, nil
		}
	}

	return entry, err
}

func (f *Filer) doListDirectoryEntries(ctx context.Context, p util.FullPath, startFileName string, inclusive bool, limit int64, prefix string, eachEntryFunc ListEachEntryFunc) (expiredCount int64, lastFileName string, err error) {
	f.maybeLazyListFromRemote(ctx, p)

	// Collect expired entries during iteration to avoid deadlock with DB connection pool
	var expiredEntries []*Entry
	var s3ExpiredEntries []*Entry
	var hasValidEntries bool

	lastFileName, err = f.Store.ListDirectoryPrefixedEntries(ctx, p, startFileName, inclusive, limit, prefix, func(entry *Entry) (bool, error) {
		select {
		case <-ctx.Done():
			glog.Errorf("Context is done.")
			return false, fmt.Errorf("context canceled: %w", ctx.Err())
		default:
			if entry.TtlSec > 0 && !entry.IsDirectory() {
				if entry.IsExpireS3Enabled() {
					if entry.GetS3ExpireTime().Before(time.Now()) && !entry.IsS3Versioning() {
						// Collect for deletion after iteration completes to avoid DB deadlock
						s3ExpiredEntries = append(s3ExpiredEntries, entry)
						expiredCount++
						return true, nil
					}
				} else if entry.Crtime.Add(time.Duration(entry.TtlSec) * time.Second).Before(time.Now()) {
					// Collect for deletion after iteration completes to avoid DB deadlock
					expiredEntries = append(expiredEntries, entry)
					expiredCount++
					return true, nil
				}
			}
			// Track that we found at least one valid (non-expired) entry
			hasValidEntries = true
			return eachEntryFunc(entry)
		}
	})
	if err != nil {
		return expiredCount, lastFileName, err
	}

	// Delete expired entries after iteration completes to avoid DB connection deadlock
	if len(s3ExpiredEntries) > 0 || len(expiredEntries) > 0 {
		for _, entry := range s3ExpiredEntries {
			if delErr := f.doDeleteEntryMetaAndData(ctx, entry, true, false, nil); delErr != nil {
				glog.ErrorfCtx(ctx, "doListDirectoryEntries doDeleteEntryMetaAndData %s failed: %v", entry.FullPath, delErr)
			}
		}
		for _, entry := range expiredEntries {
			if delErr := f.Store.DeleteOneEntry(ctx, entry); delErr != nil {
				glog.ErrorfCtx(ctx, "doListDirectoryEntries DeleteOneEntry %s failed: %v", entry.FullPath, delErr)
			}
		}

		// After expiring entries, the directory might be empty.
		// Attempt to clean it up and any empty parent directories.
		if !hasValidEntries && p != "/" && startFileName == "" {
			stopAtPath := util.FullPath(f.DirBucketsPath)
			f.DeleteEmptyParentDirectories(ctx, p, stopAtPath)
		}
	}

	return
}

// DeleteEmptyParentDirectories recursively checks and deletes parent directories if they become empty.
// It stops at root "/" or at stopAtPath (if provided).
// This is useful for cleaning up directories after deleting files or expired entries.
//
// IMPORTANT: For safety, dirPath must be under stopAtPath (when stopAtPath is provided).
// This prevents accidental deletion of directories outside the intended scope (e.g., outside bucket paths).
//
// Example usage:
//
//	// After deleting /bucket/dir/subdir/file.txt, clean up empty parent directories
//	// but stop at the bucket path
//	parentPath := util.FullPath("/bucket/dir/subdir")
//	filer.DeleteEmptyParentDirectories(ctx, parentPath, util.FullPath("/bucket"))
//
// Example with gRPC client:
//
//	if err := pb_filer_client.WithFilerClient(ctx, func(client filer_pb.SeaweedFilerClient) error {
//	    return filer_pb.Traverse(ctx, filer, parentPath, "", func(entry *filer_pb.Entry) error {
//	        // Process entries...
//	    })
//	}); err == nil {
//	    filer.DeleteEmptyParentDirectories(ctx, parentPath, stopPath)
//	}
func (f *Filer) DeleteEmptyParentDirectories(ctx context.Context, dirPath util.FullPath, stopAtPath util.FullPath) {
	if dirPath == "/" || dirPath == stopAtPath {
		return
	}

	// Safety check: if stopAtPath is provided, dirPath must be under it (root "/" allows everything)
	stopStr := string(stopAtPath)
	if stopAtPath != "" && stopStr != "/" && !strings.HasPrefix(string(dirPath)+"/", stopStr+"/") {
		glog.V(1).InfofCtx(ctx, "DeleteEmptyParentDirectories: %s is not under %s, skipping", dirPath, stopAtPath)
		return
	}

	// Additional safety: prevent deletion of bucket-level directories
	// This protects /buckets/mybucket from being deleted even if empty
	baseDepth := strings.Count(f.DirBucketsPath, "/")
	dirDepth := strings.Count(string(dirPath), "/")
	if dirDepth <= baseDepth+1 {
		glog.V(2).InfofCtx(ctx, "DeleteEmptyParentDirectories: skipping deletion of bucket-level directory %s", dirPath)
		return
	}

	// Check if directory is empty
	isEmpty, err := f.IsDirectoryEmpty(ctx, dirPath)
	if err != nil {
		glog.V(3).InfofCtx(ctx, "DeleteEmptyParentDirectories: error checking %s: %v", dirPath, err)
		return
	}

	if !isEmpty {
		// Directory is not empty, stop checking upward
		glog.V(3).InfofCtx(ctx, "DeleteEmptyParentDirectories: directory %s is not empty, stopping cleanup", dirPath)
		return
	}

	// Directory is empty, try to delete it
	glog.V(2).InfofCtx(ctx, "DeleteEmptyParentDirectories: deleting empty directory %s", dirPath)
	parentDir, _ := dirPath.DirAndName()
	if dirEntry, findErr := f.FindEntry(ctx, dirPath); findErr == nil {
		if delErr := f.doDeleteEntryMetaAndData(ctx, dirEntry, false, false, nil); delErr == nil {
			// Successfully deleted, continue checking upwards
			f.DeleteEmptyParentDirectories(ctx, util.FullPath(parentDir), stopAtPath)
		} else {
			// Failed to delete, stop cleanup
			glog.V(3).InfofCtx(ctx, "DeleteEmptyParentDirectories: failed to delete %s: %v", dirPath, delErr)
		}
	}
}

// IsDirectoryEmpty checks if a directory contains any entries
func (f *Filer) IsDirectoryEmpty(ctx context.Context, dirPath util.FullPath) (bool, error) {
	isEmpty := true
	_, err := f.Store.ListDirectoryPrefixedEntries(ctx, dirPath, "", true, 1, "", func(entry *Entry) (bool, error) {
		isEmpty = false
		return false, nil // Stop after first entry
	})
	return isEmpty, err
}

func (f *Filer) Shutdown() {
	close(f.deletionQuit)
	if f.EmptyFolderCleaner != nil {
		f.EmptyFolderCleaner.Stop()
	}
	f.LocalMetaLogBuffer.ShutdownLogBuffer()
	// The final metadata-log flush still needs the store to append its entry.
	f.LocalMetaLogBuffer.WaitForShutdown()
	f.Store.Shutdown()
}

func (f *Filer) GetEntryAttributes(ctx context.Context, p util.FullPath) (map[string][]byte, error) {
	entry, err := f.FindEntry(ctx, p)
	if err != nil {
		return nil, err
	}
	if entry == nil {
		return nil, nil
	}
	return entry.Extended, nil
}

func (f *Filer) IsDirectoryKeyObject(ctx context.Context, p util.FullPath) (bool, error) {
	entry, err := f.FindEntry(ctx, p)
	if err != nil {
		if errors.Is(err, filer_pb.ErrNotFound) {
			return false, nil
		}
		return false, err
	}
	if entry == nil {
		return false, nil
	}
	// Mirror filer_pb.Entry.IsDirectoryKeyObject so the cleaner keeps a promoted file's data.
	_, isPrefixObject := entry.Extended[s3_constants.SeaweedFSPrefixObject]
	return entry.IsDirectory() && (entry.Mime != "" || len(entry.GetChunks()) > 0 || len(entry.Content) > 0 || entry.IsInRemoteOnly() || isPrefixObject), nil
}