LVM: Optimized migration doesn't work during retype

[Rajat Dhasmana]

After change[1] merged, we allow optimized migration path even when retyping volumes.
However, when migrating a volume from one lvm backend to another, it doesn't work.

[1] https://review.opendev.org/c/openstack/cinder/+/938827

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/cinder/+/945680

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/cinder/+/945680
Committed: https://opendev.org/openstack/cinder/commit/5f59436bfbbafd31cf291015113183f0902fc06c
Submitter: "Zuul (22348)"
Branch: master

commit 5f59436bfbbafd31cf291015113183f0902fc06c
Author: Rajat Dhasmana <email address hidden>
Date: Thu Mar 27 06:26:24 2025 +0000

    Fix: LVM optimized migration path during retype

    Change[1] enabled optimized migration during retype but it
    doesn't currently work when trying to retype from one LVM
    backend to another.
    This happens because of a status check[2] happening at the
    start of the operation which checks if the volume is in
    'available' state.
    This is not true in case of retype as the status changes to
    'retyping'[3].
    Adding the 'retyping' state in the check fixes the issue and
    results in the following workflow.

    1. Create new volume in destination backend (lvmdriver-2)

    Mar 27 06:35:18 devstack-lvm-multi sudo[103853]: stack : PWD=/ ; USER=root ; COMMAND=/opt/stack/data/venv/bin/cinder-rootwrap /etc/cinder/rootwrap.conf env LC_ALL=C lvcreate -T -V 1g -n volume-f009cc14-69da-418e-a734-a4d9d7be89db stack
    -volumes-lvmdriver-2/stack-volumes-lvmdriver-2-pool

    2. Copy data from source to destination (lvmdriver-1 -> lvmdriver-2)

    Mar 27 06:35:20 devstack-lvm-multi sudo[103884]: stack : PWD=/ ; USER=root ; COMMAND=/opt/stack/data/venv/bin/cinder-rootwrap /etc/cinder/rootwrap.conf dd if=/dev/mapper/stack--volumes--lvmdriver--1-volume--f009cc14--69da--418e--a734--
    a4d9d7be89db of=/dev/mapper/stack--volumes--lvmdriver--2-volume--f009cc14--69da--418e--a734--a4d9d7be89db count=1073741824 bs=1M iflag=count_bytes,direct oflag=direct conv=sparse

    3. Remove volume from source backend (lvmdriver-1)

    Mar 27 06:35:21 devstack-lvm-multi sudo[103893]: stack : PWD=/ ; USER=root ; COMMAND=/opt/stack/data/venv/bin/cinder-rootwrap /etc/cinder/rootwrap.conf lvremove --config 'activation { retry_deactivation = 1} ' -f stack-volumes-lvmdriver-1/volume-f009cc14-69da-418e-a734-a4d9d7be89db

    The above confirms that the retype with optimized migration works when
    using LVM.

    [1] https://review.opendev.org/c/openstack/cinder/+/938827
    [2] https://opendev.org/openstack/cinder/src/commit/689c88da61017c22529e66c4266e6b332cc16370/cinder/volume/drivers/lvm.py#L760-L761
    [3] https://opendev.org/openstack/cinder/src/commit/689c88da61017c22529e66c4266e6b332cc16370/cinder/volume/api.py#L1963-L1964

    Closes-Bug: #2104334
    Change-Id: I8a14f35a119493bf4d2f4068bc378533cc40a4a3