Re: [PATCH 1/3] Send KOBJ_ADD event after dm resume ioctl.

[Peter Rajnoha <prajnoha@redhat.com>]

On 03/19/2010 04:14 PM, David Zeuthen wrote:
>> Generally, it carries hints for udev rules to instruct them
>> how they should be applied correctly, which parts should be
>> run based on the type of the device, it's real meaning with all
>> relations to other devices taken into account within that
>> DM subsystem used (e.g. LVM2's snapshots, mirrors...).
>>
>> Most of this information is really not suitable to be stored
>> as a sysfs attribute since it deals with userspace notions,
>> an abstraction layer above device-mapper...
>>
> 
> Presumably this information originates from user space when
> setting up the device-mapper device, right? Why can't you
> simply store it in, say, /var/run/device-mapper?
> 
> (Or, better, store it in /dev/.device-mapper/ to avoid hitting
> the real disk - /dev is guaranteed to be on tmpfs)

Sure, this is a possibility...

But that would mean *duplicating* the (part) of udev db functionality
(so it could be considered as another workaround?) I just asked
myself if there would be more people who could benefit from such
feature in udev db directly. A more proper and official solution
others can use if needed as well.

(Maybe we can even write our own udev daemon, called dm-udevd :))


Peter