新手伤不起啊，我把完整的代码传一下，大家看看到底怎么回事 router.post('/’, function(req, res) {

res.header('Content-Type', 'text/plain');
console.log(req.files);
var path = req.files.file.path; //获取用户上传过来的文件的当前路径
console.log(path);
var gfs =new Grid(conn.db,mongoose.mongo);
var options={
    filename: req.files.file.name +'---3',
    mode: 'w',
    chunkSize: 256,
    content_type: req.files.file.extension,
    root: 'my_collection',
    metadata: {
    }
};
var writestream = gfs.createWriteStream(options);
fs.createReadStream(path).pipe(writestream);

if (req.files.file.mimetype.split('/')[0] != 'image') {
    fs.unlink(path, function() {
        res.end('2');
    });
} else {
    imageMagick(path)
        .resize(150, 150, '!')
        .stream(function (err, stdout, stderr) {
            if(err) console.log(err);
            var option = {
                filename: req.files.file.name,
                mode: 'w',
                chunkSize: 256,
                content_type: req.files.file.extension,
                root: 'thumbnail',
                metadata: {}
            };

            console.log(option);
            async.series([function(callback){
                    console.log('jjjj');
                    var writeStream = gfs.createWriteStream(option);
                    var write = fs.createWriteStream('C:\\Users\\lqy\\Desktop\\gm.jpg');
                    var write2 = fs.createWriteStream('C:\\Users\\lqy\\Desktop\\err.txt')
                    console.log('jjjj');
                    stdout.pipe(writeStream);
                    stdout.pipe(write);
                    console.log('jjjj');
                    stderr.pipe(write2);
                    console.log('jjjj');
                    callback(null,'1')
                },
                function(callback){
                    console.log('yyyy');
                    fs.unlink(path, function(err,result) {
                        console.log('yyyy');
                        if(err)
                            console.log(err);
                        else
                            console.log('kkkk');
                        res.end('3');
                    });
                    callback(null,'1');
                }
                ],
                function(err,result)
                {
                    if(err)
                        console.log(err);
                    else
                        console.log(result);
                });
        }
    )
}

});

问题主要是两个，一个是总是生成不了缩略图，只会产生一个空的图文件，报的错误是 Permission denied @ error/blob.c/OpenBlob/2692. 另一个问题是，最前面的往数据库输入的流，也就是options和下面那部分，也是无法输入，只要我删除fs.unlink那么，缩略图正常，但是数据库输入仍然没有，为什么呢？

@20082496 求指点