[arch-projects] [RFC] [PATCH] [mkinitcpio] Cleanly stop udev >= 168 as recommended by upstream.

[Gerardo Exequiel Pozzi]

On 05/02/2011 01:22 AM, Dave Reisner wrote:
> On Mon, May 02, 2011 at 12:40:14AM -0300, Gerardo Exequiel Pozzi wrote:
>> On 05/02/2011 12:39 AM, Gerardo Exequiel Pozzi wrote:
>>> N0: udev>= 168 is needed.
>>> N1: I guess the order is correct (first cleanup then exit).
>>> N2: device-mapper/LVM udev rules must be parsed for initramfs creation
>>>      to add OPTIONS+="db_persist"
>>>
>>>>  From udev NEWS:
>>> The running udev daemon can now cleanly shut down with:
>>>    udevadm control --exit
>>>
>>> Udev in initramfs should clean the state of the udev database
>>> with: udevadm info --cleanup-db which will remove all state left
>>> behind from events/rules in initramfs. If initramfs uses
>>> --cleanup-db and device-mapper/LVM, the rules in initramfs need
>>> to add OPTIONS+="db_persist" for all dm devices. This will
>>> prevent removal of the udev database for these devices.
>>>
>>> Signed-off-by: Gerardo Exequiel Pozzi<vmlinuz386 at yahoo.com.ar>
>>> ---
>>>   init |   12 ++++--------
>>>   1 files changed, 4 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/init b/init
>>> index 7b81a1a..f586220 100644
>>> --- a/init
>>> +++ b/init
>>> @@ -118,15 +118,11 @@ elif [ ! -x "/new_root${init}" ]; then
>>>       launch_interactive_shell --exec
>>>   fi
>>>
>>> -#Special handling if udev is running
>>> -udevpid=$(/bin/pidof udevd)
>>> -if [ -n "${udevpid}" ]; then
>>> -    # Settle pending uevents, then kill udev
>>> +# Stop udevd if is running
>>> +if [ "${udevd_running}" -eq 1 ]; then
>>>       /sbin/udevadm settle
>>> -    /bin/kill ${udevpid}>   /dev/null 2>&1
>>> -    while /bin/pidof udevd>/dev/null; do
>>> -        sleep 0.1
>>> -    done
>>> +    /sbin/udevadm info --cleanup-db
>>> +    /sbin/udevadm control --exit
>>>   fi
>>>
>>>   for d in proc sys dev run; do
>> This just keep settle command.
>>
>> -- 
>> Gerardo Exequiel Pozzi
>> \cos^2\alpha + \sin^2\alpha = 1
>>
> The settle is actually unnecessary here, as its called as part of the
> udev hook.  I don't see a need to call it twice. On the other hand, I've
> notice that dracut makes the call 'udevadm control --stop-exec-queue'
> prior to shutting down udevd. Perhaps we should be using that instead?
>
> dave
>
sure?

I think this:

--------------------
launch udevd --daemon

[udev]
launch triggers
settle
[/udev]

[other hooks]
other possible uevents
[/other hooks]

at this point should wait for all uevents processed (settle) then stop 
udev (control --exit)
----------------

stop-exec-queue just ignore all events (stop process them) and queue all 
incomming events. I think this is what do not want to do.

-- 
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1