  We use a simple elastic Hamiltonian for the vortex lattice in a weak impurity
background which includes defects in the form of integer-valued fields to
calculate the free energy of a vortex lattice in the deep H_{c2} region. The
phase diagram in this regime is obtained by applying the variational approach
of M{\'e}zard and Parisi developed for random manifolds. We find a first-order
line between the Bragg-glass and vortex-glass phase as a continuation of the
melting line. In the liquid phase, we obtain an almost vertical third-order
glass transition line near the critical temperature in the H-T plane.
Furthermore, we find an almost vertical second-order phase transition line in
the Bragg-glass as well as the vortex-glass phases which crosses the
first-order Bragg-glass, vortex-glass transition line. We calculate the jump of
the temperature derivate of the induction field across this second-order line
as well as the entropy and magnetic field jumps across the first-order line.
