filer store adds kv support

can compile now, need to implement those unimplemented

weed/filer/leveldb2/leveldb2_store_kv.go

@@ -0,0 +1,56 @@
+package leveldb
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/chrislusf/seaweedfs/weed/filer"
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+func (store *LevelDB2Store) KvPut(ctx context.Context, key []byte, value []byte) (err error) {
+
+	partitionId := bucketKvKey(key, store.dbCount)
+
+	err = store.dbs[partitionId].Put(key, value, nil)
+
+	if err != nil {
+		return fmt.Errorf("kv bucket %d put: %v", partitionId, err)
+	}
+
+	return nil
+}
+
+func (store *LevelDB2Store) KvGet(ctx context.Context, key []byte) (value []byte, err error) {
+
+	partitionId := bucketKvKey(key, store.dbCount)
+
+	value, err = store.dbs[partitionId].Get(key, nil)
+
+	if err == leveldb.ErrNotFound {
+		return nil, filer.ErrKvNotFound
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("kv bucket %d get: %v", partitionId, err)
+	}
+
+	return
+}
+
+func (store *LevelDB2Store) KvDelete(ctx context.Context, key []byte) (err error) {
+
+	partitionId := bucketKvKey(key, store.dbCount)
+
+	err = store.dbs[partitionId].Delete(key, nil)
+
+	if err != nil {
+		return fmt.Errorf("kv bucket %d delete: %v", partitionId, err)
+	}
+
+	return nil
+}
+
+func bucketKvKey(key []byte, dbCount int) (partitionId int) {
+	return int(key[len(key)-1]) % dbCount
+}