California Code, Education Code - EDC § 21115

No suit, action, or proceeding shall be commenced or maintained by any person to set aside, annul, or affect the conveyance, or to affect the title to the property conveyed, or the right to the possession, or to the rents, issues, and profits thereof, unless the action is commenced within two years after the date of filing the grant for record.  No defense shall be made to any suit, action, or proceeding commenced by the trustee or trustees named in the grant, or their successors, privies, or persons holding under them, which involves the legality of the grant, or affects the title to the property conveyed, or the right to the possession, or the rents, issues, and profits thereof, unless the defense is made in a suit, action, or proceeding commenced within two years after the grant has been filed for record.