The issue about adding multipath device's targets into qemu-pr-helper's namespace

Lin Ma lma at
Wed Jul 22 13:44:26 UTC 2020

On 2020-07-22 09:44, Michal Privoznik wrote:
> On 7/20/20 4:36 PM, Lin Ma wrote:
>> On 2020-07-17 07:05, Michal Prívozník wrote:
>>> errno=9 is EBADF so maybe this is a dm issue after all?
>> Emm...So far I lean towards to an issue in libvirt code, rather than 
>> in dm.
> You might be right after all. Turns out that the mass FD closing we do
> before spawning QEMU closed /dev/mapper/control opened by earlier runs
> of virDevMapperGetTargets() and thus the pre-exec hook which called
> the function again was passing closed FD into ioctl(). I've posted
> patches:
> The first patch should be enough to fix the issue. Can you check
> please? It fixed the issue in my limited testing.

Oh, Turned out to be lack of dm_lib_release().
Confirmed, It did fix the issue.

Thanks a lot,

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