hardlink works now

weed/filer/filerstore.go

@@ -3,6 +3,8 @@ package filer
 import (
 	"context"
 	"errors"
+	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/glog"
 	"strings"
 	"time"
 
@@ -24,7 +26,7 @@ type FilerStore interface {
 	Initialize(configuration util.Configuration, prefix string) error
 	InsertEntry(context.Context, *Entry) error
 	UpdateEntry(context.Context, *Entry) (err error)
-	// err == filer2.ErrNotFound if not found
+	// err == filer_pb.ErrNotFound if not found
 	FindEntry(context.Context, util.FullPath) (entry *Entry, err error)
 	DeleteEntry(context.Context, util.FullPath) (err error)
 	DeleteFolderChildren(context.Context, util.FullPath) (err error)
@@ -42,6 +44,11 @@ type FilerStore interface {
 	Shutdown()
 }
 
+type VirtualFilerStore interface {
+	FilerStore
+	DeleteHardLink(ctx context.Context, hardLinkId HardLinkId) error
+}
+
 type FilerStoreWrapper struct {
 	ActualStore FilerStore
 }
@@ -74,6 +81,32 @@ func (fsw *FilerStoreWrapper) InsertEntry(ctx context.Context, entry *Entry) err
 	if entry.Mime == "application/octet-stream" {
 		entry.Mime = ""
 	}
+
+	if entry.HardLinkId != 0 {
+		// check what is existing entry
+		existingEntry, err := fsw.ActualStore.FindEntry(ctx, entry.FullPath)
+
+		if err == nil && entry.HardLinkId == existingEntry.HardLinkId {
+			// updating the same entry
+			if err := fsw.updateHardLink(ctx, entry); err != nil {
+				return err
+			}
+			return nil
+		} else {
+			if err == nil && existingEntry.HardLinkId != 0 {
+				// break away from the old hard link
+				if err := fsw.DeleteHardLink(ctx, entry.HardLinkId); err != nil {
+					return err
+				}
+			}
+			// CreateLink 1.2 : update new file to hardlink mode
+			// update one existing hard link, counter ++
+			if err := fsw.increaseHardLink(ctx, entry.HardLinkId); err != nil {
+				return err
+			}
+		}
+	}
+
 	return fsw.ActualStore.InsertEntry(ctx, entry)
 }
 
@@ -88,6 +121,53 @@ func (fsw *FilerStoreWrapper) UpdateEntry(ctx context.Context, entry *Entry) err
 	if entry.Mime == "application/octet-stream" {
 		entry.Mime = ""
 	}
+
+	if entry.HardLinkId != 0 {
+		// handle hard link
+
+		// check what is existing entry
+		existingEntry, err := fsw.ActualStore.FindEntry(ctx, entry.FullPath)
+		if err != nil {
+			return fmt.Errorf("update existing entry %s: %v", entry.FullPath, err)
+		}
+
+		err = fsw.maybeReadHardLink(ctx, &Entry{HardLinkId: entry.HardLinkId})
+		if err == ErrKvNotFound {
+
+			// CreateLink 1.1 : split source entry into hardlink+empty_entry
+
+			// create hard link from existing entry, counter ++
+			existingEntry.HardLinkId = entry.HardLinkId
+			if err = fsw.createHardLink(ctx, existingEntry); err != nil {
+				return fmt.Errorf("createHardLink %d: %v", existingEntry.HardLinkId, err)
+			}
+
+			// create the empty entry
+			if err = fsw.ActualStore.UpdateEntry(ctx, &Entry{
+				FullPath:   entry.FullPath,
+				HardLinkId: entry.HardLinkId,
+			}); err != nil {
+				return fmt.Errorf("UpdateEntry to link %d: %v", entry.FullPath, err)
+			}
+			return nil
+		}
+		if err != nil {
+			return fmt.Errorf("update entry %s: %v", entry.FullPath, err)
+		}
+
+		if entry.HardLinkId != existingEntry.HardLinkId {
+			// if different hard link id, moving to a new hard link
+			glog.Fatalf("unexpected. update entry to a new link. not implemented yet.")
+		} else {
+			// updating hardlink with new metadata
+			if err = fsw.updateHardLink(ctx, entry); err != nil {
+				return fmt.Errorf("updateHardLink %d from %s: %v", entry.HardLinkId, entry.FullPath, err)
+			}
+		}
+
+		return nil
+	}
+
 	return fsw.ActualStore.UpdateEntry(ctx, entry)
 }
 
@@ -102,6 +182,9 @@ func (fsw *FilerStoreWrapper) FindEntry(ctx context.Context, fp util.FullPath) (
 	if err != nil {
 		return nil, err
 	}
+
+	fsw.maybeReadHardLink(ctx, entry)
+
 	filer_pb.AfterEntryDeserialization(entry.Chunks)
 	return
 }
@@ -113,6 +196,17 @@ func (fsw *FilerStoreWrapper) DeleteEntry(ctx context.Context, fp util.FullPath)
 		stats.FilerStoreHistogram.WithLabelValues(fsw.ActualStore.GetName(), "delete").Observe(time.Since(start).Seconds())
 	}()
 
+	existingEntry, findErr := fsw.FindEntry(ctx, fp)
+	if findErr == filer_pb.ErrNotFound {
+		return nil
+	}
+	if existingEntry.HardLinkId != 0 {
+		// remove hard link
+		if err = fsw.DeleteHardLink(ctx, existingEntry.HardLinkId); err != nil {
+			return err
+		}
+	}
+
 	return fsw.ActualStore.DeleteEntry(ctx, fp)
 }
 
@@ -138,6 +232,7 @@ func (fsw *FilerStoreWrapper) ListDirectoryEntries(ctx context.Context, dirPath
 		return nil, err
 	}
 	for _, entry := range entries {
+		fsw.maybeReadHardLink(ctx, entry)
 		filer_pb.AfterEntryDeserialization(entry.Chunks)
 	}
 	return entries, err
@@ -157,6 +252,7 @@ func (fsw *FilerStoreWrapper) ListDirectoryPrefixedEntries(ctx context.Context,
 		return nil, err
 	}
 	for _, entry := range entries {
+		fsw.maybeReadHardLink(ctx, entry)
 		filer_pb.AfterEntryDeserialization(entry.Chunks)
 	}
 	return entries, nil
@@ -222,3 +318,131 @@ func (fsw *FilerStoreWrapper) KvGet(ctx context.Context, key []byte) (value []by
 func (fsw *FilerStoreWrapper) KvDelete(ctx context.Context, key []byte) (err error) {
 	return fsw.ActualStore.KvDelete(ctx, key)
 }
+
+func (fsw *FilerStoreWrapper) createHardLink(ctx context.Context, entry *Entry) error {
+	if entry.HardLinkId == 0 {
+		return nil
+	}
+	key := entry.HardLinkId.Key()
+
+	_, err := fsw.KvGet(ctx, key)
+	if err != ErrKvNotFound {
+		return fmt.Errorf("create hardlink %d: already exists: %v", entry.HardLinkId, err)
+	}
+
+	entry.HardLinkCounter = 1
+
+	newBlob, encodeErr := entry.EncodeAttributesAndChunks()
+	if encodeErr != nil {
+		return encodeErr
+	}
+
+	return fsw.KvPut(ctx, key, newBlob)
+}
+
+func (fsw *FilerStoreWrapper) updateHardLink(ctx context.Context, entry *Entry) error {
+	if entry.HardLinkId == 0 {
+		return nil
+	}
+	key := entry.HardLinkId.Key()
+
+	value, err := fsw.KvGet(ctx, key)
+	if err == ErrKvNotFound {
+		return fmt.Errorf("update hardlink %d: missing", entry.HardLinkId)
+	}
+	if err != nil {
+		return fmt.Errorf("update hardlink %d err: %v", entry.HardLinkId, err)
+	}
+
+	existingEntry := &Entry{}
+	if err = existingEntry.DecodeAttributesAndChunks(value); err != nil {
+		return err
+	}
+
+	entry.HardLinkCounter = existingEntry.HardLinkCounter
+
+	newBlob, encodeErr := entry.EncodeAttributesAndChunks()
+	if encodeErr != nil {
+		return encodeErr
+	}
+
+	return fsw.KvPut(ctx, key, newBlob)
+}
+
+func (fsw *FilerStoreWrapper) increaseHardLink(ctx context.Context, hardLinkId HardLinkId) error {
+	if hardLinkId == 0 {
+		return nil
+	}
+	key := hardLinkId.Key()
+
+	value, err := fsw.KvGet(ctx, key)
+	if err == ErrKvNotFound {
+		return fmt.Errorf("increaseHardLink %d: missing", hardLinkId)
+	}
+	if err != nil {
+		return fmt.Errorf("increaseHardLink %d err: %v", hardLinkId, err)
+	}
+
+	existingEntry := &Entry{}
+	if err = existingEntry.DecodeAttributesAndChunks(value); err != nil {
+		return err
+	}
+
+	existingEntry.HardLinkCounter++
+
+	newBlob, encodeErr := existingEntry.EncodeAttributesAndChunks()
+	if encodeErr != nil {
+		return encodeErr
+	}
+
+	return fsw.KvPut(ctx, key, newBlob)
+}
+
+func (fsw *FilerStoreWrapper) maybeReadHardLink(ctx context.Context, entry *Entry) error {
+	if entry.HardLinkId == 0 {
+		return nil
+	}
+	key := entry.HardLinkId.Key()
+
+	value, err := fsw.KvGet(ctx, key)
+	if err != nil {
+		glog.Errorf("read %s hardlink %d: %v", entry.FullPath, entry.HardLinkId, err)
+		return err
+	}
+
+	if err = entry.DecodeAttributesAndChunks(value); err != nil {
+		glog.Errorf("decode %s hardlink %d: %v", entry.FullPath, entry.HardLinkId, err)
+		return err
+	}
+
+	return nil
+}
+
+func (fsw *FilerStoreWrapper) DeleteHardLink(ctx context.Context, hardLinkId HardLinkId) error {
+	key := hardLinkId.Key()
+	value, err := fsw.KvGet(ctx, key)
+	if err == ErrKvNotFound {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+
+	entry := &Entry{}
+	if err = entry.DecodeAttributesAndChunks(value); err != nil {
+		return err
+	}
+
+	entry.HardLinkCounter--
+	if entry.HardLinkCounter <= 0 {
+		return fsw.KvDelete(ctx, key)
+	}
+
+	newBlob, encodeErr := entry.EncodeAttributesAndChunks()
+	if encodeErr != nil {
+		return encodeErr
+	}
+
+	return fsw.KvPut(ctx, key, newBlob)
+
+}