[linux-lvm] lvdisplay "open" field computing

[Simon ELBAZ]

Thank you very much Zdenek.

I will suggest the customer a kernel update.

On 10/07/2019 15:32, Zdenek Kabelac wrote:
> Dne 10. 07. 19 v 13:54 Simon ELBAZ napsal(a):
>> Hi Zdenek,
>>
>> Thanks for your feedback.
>>
>> The kernel version is:
>>
>> [root at panoramix ~]# uname -a
>> Linux panoramix.ch-perrens.fr 2.6.32-573.12.1.el6.x86_64 #1 SMP Tue 
>> Dec 15 21:19:08 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
>>
>
> Hi
>
> So this is really a very historical kernel - released ~10 years back.
> I'm afraid none is going to look out for the reasoning of any kernel 
> bug....
>
> It might be interesting to see if you get any reproducer to give you 
> hints
> how to avoid this happen (at least not easily).
>
>> Jul  2 03:08:10 panoramix LVM(pri_ISCSIVG0_vg_obm)[18618]: INFO: 
>> Retry deactivating volume group vg_obm
>>
>> This is why I am trying to understand how the field is computed.
>
> Simple rule applied here: DM devices in use (open_count > 0) cannot be 
> deactivated.
>
> Occasionally there were 'race events' with udev - where device
> which should have been otherwise unused has been asynchronously
> opened by udev scanning rules - but that's like is not your case.
>
> As you seems to have device open count higher permanently -
>
> So if you are sure there is no running 'APP' after umount, that
> keeps device open - it could be likely be some very old bug in kernel
> with very high probably 99.99999% of being fixed ;)
>
> Regards
>
>
> Zdenek
>
-- 
Simon Elbaz
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