beef barley soup recipe

2 tablespoons olive oil - 1 pound beef stew meat, cut into bite-sized pieces - Salt and black pepper to taste - 1 large onion, chopped - 2 cloves garlic, minced - 3 carrots, peeled and sliced - 3 celery stalks, sliced - 8 cups beef broth - 1 can (14.5 ounces) diced tomatoes, with juice - 1 cup pearl barley, rinsed - 1 teaspoon dried thyme - 1 teaspoon dried rosemary - 1 bay leaf - 2 cups mushrooms, sliced - 2 tablespoons fresh parsley, chopped (for garnish)