[PATCH] libdm-iface: not output error message inside retry loops

[Zdenek Kabelac <zkabelac@redhat.com>]

Dne 28.8.2015 v 04:58 Liuhua Wang napsal(a):
> Hi Zdenek,
>
> Thanks for your reply.
>
>> It's in fact made 'noisy' intentionally - we normally should detect whether
>> retry makes sense - so  what are the conditions when you experience this
>> problem ?
>>
>> Common scenario:
>>
>> The major reason for retry is 'unpredictable'  udev event processing
>> i.e. you run  'umount' -> fires watch-rule -> lvremove  could have failed -
>> retry fixes this problem.
>
>   We first found this problem when we were testing lvcreate-usage.sh included in
>   lvm2-2.02.120 package. The case always failed due to the following message:
>    device-mapper: remove ioctl on (253:6) failed: Device or resource busy
>   [ 0:01]   Node @TESTDIR@/dev/mapper/@PREFIX at vg-LV2-cow was not removed by udev. Falling back to direct node removal.

Looks like udev issue.


>
> Then we tested more cases and found the problem occurs in the following cases:
>     - lvremove/lvcreate a snap lv
>     - lvremove/lvcreate a thin lv
>     - lvremove/lvcreate a mirror lv
>
> o Reproduce frequency:
>     lvremove about 80%, lvcreate occurs occasionally
>
> With the patch I attached, the lvcreate-usage.sh will not fail due to the error message.

What is your system - is it Debian/Ubuntu?

These tests depend on properly working udev rules.


Zdenek