Re: udev 145, when are events fully processed?

[Nigel Kukard <nkukard@lbsd.net>]

>>
>> Trying to figure something out here, using the following I'm seeing a
>> delay in the creation of block devices in /dev ...
>>
>> # trigger the sorted events
>> echo -e '\000\000\000\000'>  /proc/sys/kernel/hotplug
>>
>> rm -fr /dev/.udev>  /dev/null 2>&1
>> mkdir -p /dev/.udev>  /dev/null 2>&1
>> /sbin/udevd
>>
>> # Not entirely sure what this is for
>> /sbin/udevadm control --env=STARTUP=1
>> /sbin/udevadm trigger
>
>> /sbin/udevadm settle
>
> settle should have waited until all events have been processed

Does this mean fully processed or just received?  I asked on
#udev/irc.freenode.net and was told that settle only waits until udev
had received them.

The only reason it worked before was because of the speed improvements
made recently.


>> # Nor sure what this does
>> /sbin/udevadm control --env=STARTUP>>
>>
>> I think my problem is, while all the events have been sent to udevd
>> there is a delay if I do a  "fsck LABEL=root" straight on say the next
>> line,  a "ls" shows that none of the block devices exist until a second
>> or two later. A sleep 5 before my "ls" works around this and the block
>> devices show up.
>>
>> Any ideas how I can determine once all udev events have finished
>> processing so I can continue boot?
>
> check would look like:
> /sbin/udevadm settle --timeout=0 || echo "Still not all udev events
> processed"
>
> waiting should be:
> /sbin/udevadm settle
Same result on both.

I went further and wrote a small C app to wait for the udev event, this
works 100%. I run the C app in the background before I run trigger &
settle, then do a "wait" until it returns.

-N