Sort of a feature proposal

Hi, I have some large git repositories on a USB drive (ext3 file system). That means that when replugging the drive, the recorded st_dev data in the index is off, meaning that the whole repo directory structure gets reread as the stat data of all directories has changed.

That's a nuisance. Can't we have some heuristic or configuration option where we, say, record the st_dev of the _index_ file, and if that has changed, we propagate that change to the st_dev of its contents? I'd like to see something that works more efficiently than rescanning the whole disk every time I hibernate my computer.

Thanks,