Re: [RFC] coldplug - emit hotplug events from sysfs

[Olivier Blin <oblin@mandriva.com>]

Bill Nottingham <notting@redhat.com> writes:

> Olivier Blin (oblin@mandriva.com) said: 
>> > Ok, that's just as hacky as grovelling around in ps I guess, but at
>> > least it has the advantage that there's no possibility of no udev
>> > processes having been started by the next line of shell - which there is
>> > with your example.
>> >
>> > There's almost certainly a more elegant way, but basically mark the
>> > events you're waiting for and wait for them all to come back.
>> 
>> We could have a lock directory, in which a lock file would be added for
>> each event (using the full path with '/' replaced by '%' for example).
>> This lock file would be removed once udev is done processing the event.
>> But is it easy to remove a lock file when a PROGRAM or RUN rule is
>> used? Maybe by catching signals of this program.
>
> Realistically, how often are you doing udev coldplug with a writable
> system filesystem? I'd suspect at least in our case, any coldplug
> would be well before the root fs is read/write.

That's right, coldplug is often done when the root fs isn't writable
yet. But it isn't really a problem, we could use something like
/dev/.udevdb/, for example /dev/.udevlock/

-- 
Olivier Blin
Mandriva



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