BackupSetAt
BackupSetAt(inode->Block(),used);
if (!BackupSetAt(block, used)) {
BackupSetAt(fDisk->ToBlock(node->data.indirect), used);
if (!BackupSetAt(block, used))
BackupSetAt(fDisk->ToBlock(node->data.double_indirect), used);
if (!BackupSetAt(block, true))
bool BackupSetAt(off_t block,bool used);