Creation volume from image fails due to cinder miscalculates the available size

[Denis Kostryukov]

Cinder fails when checking if there's enough space available on the target device.
When Cinder uses "check_available_space()" fuction to check if there's enough space on the bootable volume, it fails if free disk space on "/dev" filesystem less than the image virtual size.
It happens because the "check_available_space()" fuction checks free space in "/dev" directory instead of "/dev/disk/by-id/dm-uuid-mpath*" device.

MOS 9.2 Drop2018w07
Cinder storage backend is EMC VNX.

[Denis Kostryukov (dkostryukov)]

sla1 for 9.0-updates

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: 9.0/mitaka
Change author: Denis V. Meltsaykin <email address hidden>
Review: https://review.fuel-infra.org/38381

[Fuel Devops McRobotson (fuel-devops-robot)]

Reviewed: https://review.fuel-infra.org/38381
Submitter: Pkgs Jenkins <email address hidden>
Branch: 9.0/mitaka

Commit: d80f5b8b90175a7c6f6374272f2f82122c4e2f79
Author: Denis V. Meltsaykin <email address hidden>
Date: Thu Apr 26 15:56:43 2018

Fix checking for available space when creating a volume from image

In several cases the existing check works incorrect. For example with LVM,
ScaleIO and other drivers that call conversion of images directly to block
devices such as iSCSI or LVM volumes. In this case the check returns free
space of the /dev/ partition instead of free space of the destination device.
Moreover, this check is not needed in that case, because if the device
exists and we get here then it already has the needed size.

Change-Id: I52d944ba32f41ea584d902c334bfa9acfbcd84f0
Closes-Bug: #1766907

[Dmitry (dtsapikov)]

Verified on 9.2+mu6