FUSE mount: atomic local cache updates

weed/filesys/meta_cache/meta_cache.go

@@ -1,20 +1,24 @@
 package meta_cache
 
 import (
+	"context"
 	"os"
+	"sync"
 
 	"github.com/chrislusf/seaweedfs/weed/filer2"
 	"github.com/chrislusf/seaweedfs/weed/filer2/leveldb"
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
 type MetaCache struct {
-	filer2.FilerStore
+	actualStore filer2.FilerStore
+	sync.RWMutex
 }
 
 func NewMetaCache(dbFolder string) *MetaCache {
 	return &MetaCache{
-		FilerStore: openMetaStore(dbFolder),
+		actualStore: openMetaStore(dbFolder),
 	}
 }
 
@@ -35,3 +39,55 @@ func openMetaStore(dbFolder string) filer2.FilerStore {
 	return store
 
 }
+
+func (mc *MetaCache) InsertEntry(ctx context.Context, entry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.InsertEntry(ctx, entry)
+}
+
+func (mc *MetaCache) AtomicUpdateEntry(ctx context.Context, oldPath util.FullPath, newEntry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	if oldPath != "" {
+		if err := mc.actualStore.DeleteEntry(ctx, oldPath); err != nil {
+			return err
+		}
+	}
+	if newEntry != nil {
+		if err := mc.actualStore.InsertEntry(ctx, newEntry); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (mc *MetaCache) UpdateEntry(ctx context.Context, entry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.UpdateEntry(ctx, entry)
+}
+
+func (mc *MetaCache) FindEntry(ctx context.Context, fp util.FullPath) (entry *filer2.Entry, err error) {
+	mc.RLock()
+	defer mc.RUnlock()
+	return mc.actualStore.FindEntry(ctx, fp)
+}
+
+func (mc *MetaCache) DeleteEntry(ctx context.Context, fp util.FullPath) (err error) {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.DeleteEntry(ctx, fp)
+}
+
+func (mc *MetaCache) ListDirectoryEntries(ctx context.Context, dirPath util.FullPath, startFileName string, includeStartFile bool, limit int) ([]*filer2.Entry, error) {
+	mc.RLock()
+	defer mc.RUnlock()
+	return mc.actualStore.ListDirectoryEntries(ctx, dirPath, startFileName, includeStartFile, limit)
+}
+
+func (mc *MetaCache) Shutdown() {
+	mc.Lock()
+	defer mc.Unlock()
+	mc.actualStore.Shutdown()
+}

weed/filesys/meta_cache/meta_cache_subscribe.go

@@ -16,12 +16,11 @@ func SubscribeMetaEvents(mc *MetaCache, client filer_pb.FilerClient, dir string,
 
 	processEventFn := func(resp *filer_pb.SubscribeMetadataResponse) error {
 		message := resp.EventNotification
-		ctx := context.Background()
-		var err error
+		var oldPath util.FullPath
+		var newEntry *filer2.Entry
 		if message.OldEntry != nil {
-			key := util.NewFullPath(resp.Directory, message.OldEntry.Name)
-			glog.V(4).Infof("deleting %v", key)
-			err = mc.DeleteEntry(ctx, key)
+			oldPath = util.NewFullPath(resp.Directory, message.OldEntry.Name)
+			glog.V(4).Infof("deleting %v", oldPath)
 		}
 
 		if message.NewEntry != nil {
@@ -31,9 +30,9 @@ func SubscribeMetaEvents(mc *MetaCache, client filer_pb.FilerClient, dir string,
 			}
 			key := util.NewFullPath(dir, message.NewEntry.Name)
 			glog.V(4).Infof("creating %v", key)
-			err = mc.InsertEntry(ctx, filer2.FromPbEntry(dir, message.NewEntry))
+			newEntry = filer2.FromPbEntry(dir, message.NewEntry)
 		}
-		return err
+		return mc.AtomicUpdateEntry(context.Background(), oldPath, newEntry)
 	}
 
 	for {