filer: DeleteFolderChildren for deleting large folders

weed/filer2/leveldb2/leveldb2_store.go

@@ -8,12 +8,13 @@ import (
 	"io"
 	"os"
 
-	"github.com/chrislusf/seaweedfs/weed/filer2"
-	"github.com/chrislusf/seaweedfs/weed/glog"
-	weed_util "github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 	leveldb_util "github.com/syndtr/goleveldb/leveldb/util"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	weed_util "github.com/chrislusf/seaweedfs/weed/util"
 )
 
 func init() {
@@ -134,6 +135,34 @@ func (store *LevelDB2Store) DeleteEntry(ctx context.Context, fullpath filer2.Ful
 	return nil
 }
 
+func (store *LevelDB2Store) DeleteFolderChildren(ctx context.Context, fullpath filer2.FullPath) (err error) {
+	directoryPrefix, partitionId := genDirectoryKeyPrefix(fullpath, "", store.dbCount)
+
+	batch := new(leveldb.Batch)
+
+	iter := store.dbs[partitionId].NewIterator(&leveldb_util.Range{Start: directoryPrefix}, nil)
+	for iter.Next() {
+		key := iter.Key()
+		if !bytes.HasPrefix(key, directoryPrefix) {
+			break
+		}
+		fileName := getNameFromKey(key)
+		if fileName == "" {
+			continue
+		}
+		batch.Delete(append(directoryPrefix, []byte(fileName)...))
+	}
+	iter.Release()
+
+	err = store.dbs[partitionId].Write(batch, nil)
+
+	if err != nil {
+		return fmt.Errorf("delete %s : %v", fullpath, err)
+	}
+
+	return nil
+}
+
 func (store *LevelDB2Store) ListDirectoryEntries(ctx context.Context, fullpath filer2.FullPath, startFileName string, inclusive bool,
 	limit int) (entries []*filer2.Entry, err error) {