前端代码

 //profile settings
    var avatarData = '';
    upload.preview('avatar','preview-avatar',function(data){
        avatarData = data;//base64
    });

    new Vue({
        el:'#profile-form',
        data:{
            profile:{
                nickname:'',
                sex:profileSex,
                company:'',
                avatar:'',
                description:'',
                github:'',
                weibo:''
            }
        },
        methods:{
            submit:function(e){
                e.preventDefault();
                loadin.show('load');
                var profileData = this.$data.profile;
                if(avatarData){
                    avatarData = avatarData.replace(/^data:image\/\w+;base64,/,'');
                }
                profileData.avatar = avatarData;
                $.ajax({type:'POST',url:'/profile',data:profileData}).then(function(ret){
                    ret = JSON.parse(ret);
                    if(ret.status){
                        loadin.show('alert',ret.msg,'success');
                        setTimeout(function(){
                            location.reload();
                        },1000);
                    }
                },function(){});
            }
        }
    });

后端代码

//profile
    user.profile = function* (){
        var body = this.request.body,
            nickname = body.nickname,
            sex = body.sex,
            company=body.company,
            avatar = body.avatar,
            description= body.description,
            github=body.github,
            weibo = body.weibo;

        if(avatar){
            var imgbuffer = new Buffer(avatar,'base64');
            var imgName = yield model.get({email:this.session.user.email},'avatar');
            if(/custom/.test(imgName.avatar)){
                imgName = 'assets'+imgName.avatar;
            }else{
                imgName = 'assets/customavatar/petitspois:'+(+new Date)+(Math.random()*1000|0)+'.png';
            }

            yield fs.writeFile(imgName,imgbuffer);

        }

        var profile = {
            nickname:nickname,
            sex: sex,
            company:company,
            description:description,
            github:github,
            weibo:weibo
        }

        avatar && (profile.avatar = imgName.slice(6));

        var update =  yield model.update({email:this.session.user.email},{$set:profile});

        if(update){
            this.body = {
                msg:'更新成功',
                status:1
            }
        }


    }

默认头像为一个随机的图片url,当自定义后就写入新的url。但是需要重启node.怎么才可以解决呢?