private boolean isHdfsAclSet(Table aclTable, String userName, String namespace,
    TableName tableName) throws IOException {
    boolean isSet = SnapshotScannerHDFSAclStorage.hasUserGlobalHdfsAcl(aclTable, userName);
    if (namespace != null) {
      isSet = isSet
        || SnapshotScannerHDFSAclStorage.hasUserNamespaceHdfsAcl(aclTable, userName, namespace);
    }
    if (tableName != null) {
      isSet = isSet
        || SnapshotScannerHDFSAclStorage.hasUserNamespaceHdfsAcl(aclTable, userName,
          tableName.getNamespaceAsString())
        || SnapshotScannerHDFSAclStorage.hasUserTableHdfsAcl(aclTable, userName, tableName);
    }
    return isSet;
  }
Check if user global/namespace/table HDFS acls is already set
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/SnapshotScannerHDFSAclController.java