Comment 40 for bug 1834875

> Dan had put a udevadm settle in this spot like so
>
> def get_size(filename)
> util.subp(['udevadm', 'settle'])
> os.open(....)

if you know you've just changed (e.g.) /dev/sda, possibly its kernel-generated udev events just haven't reached udev yet, so the immediate call to 'udev settle' has nothing to wait for; maybe you should tell udev to explicitly request a new full set of events and settle on that?

udevadm trigger --settle /dev/sda