disk become empty after delete a large file
The first thing I try is testdisk. Choose the advanced mode, I find my files all are there. Cheers!

I copy them all out. Then I try further to get the disk repaired so that it show all files.  But further try on testdisk results nothing. 

Then I google a little more. And find ntfs is more compatible in windows. So I mount the disk on windows and use chkdsk. 10 min later, all things become right!