1. A method for re-establishing out-of-band metadata in a lower layer of a storage stack of a computer system comprising an upper layer and that lower layer, comprising: determining, by the upper layer, that out-of-band metadata in the lower layer may have become out of sync; determining, by the upper layer, a set of metadata maintenance commands for the lower layer, independent of whether those commands have already been issued, and independent of whether a portion of the lower layer has become free; sending, by the upper layer, the set of metadata maintenance commands to the lower layer; and modifying, by the lower layer, the data and/or metadata stored in the lower layer, in response to receiving the set of metadata maintenance commands.