How to quickly find added / removed files?

Question

I am writing a little program that creates an index of all files on my directories. It basically iterates over each file on the disk and stores it into a searchable database

Answer 1

One way you could speed things up is to just iterate over the directories and check the last modified time to see if the contents of the directory have changed since your last index, and if they have just do a normal scan on the directory then and see if you can find where things changed. I don't know how portable this will be tho, but it changing the hierarchy propagates up on a Linux system (might be filesystem dependant) so you can start at the root and work your way down, stopping when you hit a directory that hasn't changed