On 01/24/2014 02:24 PM, Peter Rajnoha wrote:
> On 01/23/2014 01:35 PM, Marius Vollmer wrote:
>> Peter Rajnoha <prajnoha@redhat.com> writes:
>>
>>> On 01/22/2014 10:23 AM, Marius Vollmer wrote:
>>>
>>>> Is it guaranteed (modulo bugs) that the DM_UDEV_DISABLE_*_RULES flags
>>>> are only ever removed from a node, and are never added to it over it's
>>>> lifetime between add/remove events?
>>>
>>> No, we don't have this restriction generally
>>
>> Ok.
>>
>>>> This isn't true right now, and UDisks fails to handle it correctly
>>>> when a flag is added in a "change" event. I am asking to figure out
>>>> where the fix should go.
>>>
>>> Well, udisks should always check the DM_UDEV_DISABLE_OTHER_RULES_FLAG
>>> and if it's set, skip its processing. It already has:
>>>
>>> # honor the flag that device-mapper sets if the device should be ignored
>>> ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", GOTO="udisks_end"
>>>
>>> ..in 80-udisks.rules. So it should be already following this.
>>
>> That's from UDisks 1, I am concerned with UDisks2, which is a quite
>> different beast, I think. Sorry for not making this clear.
>>
>> The problem with UDisks2, as I see it, is that it ignores a "change" or
>> "add" event that has DM_UDEV_DISABLE_OTHER_RULES_FLAG set, while I think
>> it should treat it as a "remove" event.
>>
>> I have proposed this patch:
>>
>> https://bugs.freedesktop.org/attachment.cgi?id=92577&action=edit
>
> Well, I don't quite agree with this statement from the patch:
> "We treat the uevent as "remove" if the device-mapper layer
> requests that other rules ignore this uevent".
>
> The flag (DM_UDEV_DISABLE_OTHER_RULES_FLAG) is here to direct
> udev processing to skip any scans - it's not actually saying
> everyone else should remove this device now. It's just saying
> "don't access/touch it" when this flag is set. If there was a
> situation where we really need to remove (deactivate) the device,
> we'd do that in lvm2 directly within processing of the device.
...simply, the event listener that gets the event with this flag
set should just consider this dm device as "private".
--
Peter
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