We show how the Clark-Ocone-Haussmann formula for Brownian motion on a compact Riemannian manifold put forward by S. Fang in his proof of the spectral gap inequality for the Ornstein-Uhlenbeck operator on the path space can yield in a very simple way the logarithmic Sobolev inequality on the same space. By an appropriate integration by parts formula the proof also yields in the same way a logarithmic Sobolev inequality for the path space equipped with a general diffusion measure as long as the torsion of the corresponding Riemannian connection satisfies Driver's total antisymmetry condition.
"Martingale Representation and a Simple Proof of Logarithmic Sobolev Inequalities on Path Spaces." Electron. Commun. Probab. 2 71 - 81, 1997. https://doi.org/10.1214/ECP.v2-986