2. Preconditions

It is really important that you unmount the affected partition immediately before doing anything else with it. If you have copied around some files in this partition after the accident, then the chance for this method to work has lowered a lot.

Also you must have a quite new kernel, because the 2.0.x and below zeroes indirect blocks, which will not make this process to work for files with more than 12 blocks of data.

I will describe one method of recovery and I will not leave out much for error handling. If you suspect that some step described below went wrong, I do not recommend you to go any further.