jfinal在centos上上传文件时出现权限不够?报错

@Jfinal ,我把jfinal项目部署到centos上上传文件时报错，貌似是不可写入，可是upload目录的权限就是755啊
上传用的是百度的web uploader插件

报错部分：

[ERROR]-[Thread: http-apr-8080-exec-5]-[com.jfinal.core.ActionHandler.handle()]: /upload
java.lang.IllegalArgumentException: Not writable: /data/wwwroot/default/upload

后台代码：

public void upload() {
	UploadFile uploadFile = getFile();
	String oldFileName = uploadFile.getFileName();
	String newFileName = UUID.randomUUID().toString() + oldFileName.substring(oldFileName.indexOf("."));
	uploadFile.getFile().renameTo(new File(uploadFile.getUploadPath() + File.separator + newFileName));
	int bugId = getSessionAttr("bugId");
	new Img().set("img_path", newFileName).set("bug_id", bugId).set("type", 1).save();
	renderNull();
}

// 实例化
uploader = WebUploader.create({
	pick : {
		id : '#filePicker',
		multiple : true
	},
	dnd : '.queueList',
	paste : document.body,
	accept : {
		title : 'Images',
		extensions : 'gif,jpg,jpeg,bmp,png',
		mimeTypes : 'image/*'
	},

	// swf文件路径
	swf : 'Uploader.swf',

	disableGlobalDnd : true,
	
	chunked : true,
	// server: 'http://webuploader.duapp.com/server/fileupload.php',
	server : '/upload',
	fileNumLimit : 300,
	fileSizeLimit : 200 * 1024 * 1024, // 20 M
	fileSingleSizeLimit : 10 * 1024 * 1024 // 5 M
});