Add support for multipath devices

[control-d]

Previously, when a device-mapper multipath device was specified for DEVS setup would fail with "Partition specification unsupported at this time." Each device is checked to see if it has a parent, and, if so, it is assumed to be a partition. Multipath devices are not partitions, and their backing paths are reported as parent devices.

This change adds the ability to correctly identify multipath devices by checking for device type of "mpath" so that they are not mistaken for partitions.

This should resolve RHBZ #1496295 - container-storage-setup fails on multipath device

[rh-atomic-bot]

Can one of the admins verify this patch? I understand the following commands:

• bot, add author to whitelist
• bot, test pull request
• bot, test pull request once

[rhatdan]

bot, add author to whitelist

[rhatdan]

bot, test pull request

[rhatdan]

LGTM @rhvgoyal PTAL

[rhvgoyal]

@control-d Can you update commit message of the patch. Describe well what exactly is the problem and how your patch fixes it.

[control-d]

I've updated the commit message. Thanks.

[rhvgoyal]

@control-d Two things.

• I came across a rhel system where multipath device type is being reported as "dm" and not "mpath". Not sure when was it changed. We will hvae to take care of that case as well.

• What about the type of partition. Does this patch detects partition multipath device correctly and errors out?

[rhvgoyal]

Ok, this works for me. I tested multipath both on fedora and rhel images and also tested error paths and it worked.

I guess it works because "lsblk" reports partition device as type "part" for multipath. So if /dev/mapper/mpath1 is partition, it is correctly detected and reported as error.

LGTM

[rhvgoyal]

@rh-atomic-bot r+ ea8643c

[rh-atomic-bot]

:zap: Test exempted: merge already tested.