Section 6. The petition shall set forth on oath the nature and extent of the share of each co-tenant, so far as known to the petitioner, stating whether he has an estate of inheritance, for life or for years, whether in possession, remainder or reversion, and whether vested or contingent. It shall contain a description of each parcel of land sufficiently specific for identification. If the common title is derived by will or inheritance from a common ancestor, the name of the testator or common ancestor shall be given; if under a deed, reference shall be made thereto. The petition shall be in the alternative, praying for division of the land or for the sale, either public or private, of all or any part thereof which the court may find cannot be advantageously divided. If a private sale is desired, the minimum sum for which the sale may be made shall be stated. Only persons having legal title to an estate for years, for life or in fee, whether in possession, reversion or remainder, shall be necessary or proper parties. Mortgagees, lienors, attaching creditors and other persons having or claiming encumbrances on the land shall not be parties, but shall be named in the petition and given such notice as the court may order, and shall be permitted to intervene so far as may be necessary to protect their interests in the land or to establish their rights in the proceeds of a sale.