Patch fixing bug #1861071 resolved the issue of extending LUKS v1
volumes when nova connects them via libvirt instead of through os-brick,
but nova side still fails to extend LUKSv2 in-use volumes when they
don't go through libvirt.
The logs will show a very similar error, but the user won't know that
this has happened and Cinder will show the new size:
libvirt.libvirtError: internal error: unable to execute QEMU command
'block_resize': Cannot grow device files
There are 2 parts to this problem:
- The device mapper device is not automatically extended.
- Nova tries to use the encrypted block device size as the size of the
decrypted device.
This patch adds new functionality to the encryptors so that they can
extend decrypted volumes to match the size of the encrypted device.
New method added to encryptors is called "extend_volume", and should be
called after the homonymous method in the connector has been called, and
the value returned by the encryptor's extend_volume method is the real
size of the decrypted volume (encrypted volume - headers).
The patch only adds functionality for LUKS and LUKSv2 volumes, not to
cryptsetup volumes.
Related-Bug: #1967157
Change-Id: I351f1a7769c9f915e4cd280f05a8b8b87f40df84
a9a53f9b50