current_time('mysql') get wrong time

I'm using wordpress and I for media upload, I checked uploadsuseyearmonth_folders. Even though it is late August now, my uploads still go to folder "2016/07/"

I revised wp-includes/functions.php to include the days and get the following

~~http://tianyi.li/wp-content/uploads/201 … 0-5@2x.png">http://tianyi.li/wp-content/uploads/2016/08/QQ20160820-5@2x.png" />

and what I get is like:

~~http://tianyi.li/wp-content/uploads/201 … 0-6@2x.png">http://tianyi.li/wp-content/uploads/2016/08/QQ20160820-6@2x.png" />

so today is 20th August, but the upload reads as 25th July.

I think this time goes from mysql, but when I check the mysql time, I get:

~~http://tianyi.li/wp-content/uploads/201 … 0-7@2x.png">http://tianyi.li/wp-content/uploads/2016/08/QQ20160820-7@2x.png" />

Something cause this maybe few days ago, I use the option 2 in the following article to backup and recover my database,

https://www.linode.com/docs/databases/m … -databases">https://www.linode.com/docs/databases/mysql/back-up-your-mysql-databases

which overrides all the files in mysql folder.

So, for now, I ask for help and is there anyone knows how to fix it?~~