  We derive the fully backreacted bulk solution dual to a boundary superfluid
with finite supercurrent density in AdS/CFT. The non-linear boundary
hydrodynamical description of this solution is shown to be governed by a
relativistic version of the Tisza-Landau two-fluid model to non-dissipative
order. As previously noted, the phase transition can be both first order and
second order, but in the strongly-backreacted regime at low charge q we find
that the transition remains second order for all allowed fractions of
superfluid density.
