SMB_XA_FLAG_OPEN
ASSERT((xa->xa_flags & SMB_XA_FLAG_OPEN) == 0);
xa->xa_flags |= SMB_XA_FLAG_OPEN;
xa->xa_flags &= ~SMB_XA_FLAG_OPEN;
#define SMB_XA_CLOSED(xa) (!((xa)->xa_flags & SMB_XA_FLAG_OPEN))