Re: [ANNOUNCE] udev 0.1 release

Arnd Bergmann
2003-04-11T22:01:34Z

On Friday 11 April 2003 23:57, Greg KH wrote:

> No, you want to make sure you have the same "name" after that. As any
> userspace apps that had a open file on the original disks are basically
> screwed anyway, we want a way to enable them to recover nicely.
>
> And no, I don't want to go into the whole, remove a device and plug it
> back in, and userspace never noticed the difference while it held an
> open file handle. That's a problem I don't want to even go near right
> now, and is totally different from what udev is trying to do :)

Ok, but that still leaves the race between creation and removal of devices
files. In my scenario three different bad things can happen:

- The file is removed after the device is added
- The file is added when the device is already unplugged again
- The file gets added with the wrong device number -> worst case

This can be avoided by completely serializing all events, both inside
the kernel and the execution of /sbin/hotplug, but that might cause
significant downtime.