Rooting Samsung Galaxy S II GT-i9100 How does one root a Samsung Galaxy S II GT-i9100 (with its original Android 2.3 Gingerbread), preferably under Linux Mint?

This questions pertains specifically the GT-i9100 version (not GT-i9100G nor GT-i9100T, et cetera), which currently has no entry under the rooting index.

I am particularly looking for a rooting method which does not wipe the data on the phone, as I am hoping to recover data afterwards. I have an 8GB external SD card.
You need the file http://forum.xda-developers.com/attachment.php?attachmentid=1674014&amp;d=1359080668 here and copy it to the external SD card (the one you connect to a slot in the phone)
Steps:


Save the file to external sd card
Open stock recovery (press power + vol up + home button)
Install zip from external sd card
Choose the file "CWM-SuperSU-v0.97.zip" from the SD card


Flash it and then reboot