[lvm-devel] dm: introduce DM_GET_TARGET_VERSION
Mike Snitzer
snitzer at redhat.com
Tue Sep 17 20:08:28 UTC 2019
On Tue, Sep 17 2019 at 11:44am -0400,
John Dorminy <jdorminy at redhat.com> wrote:
> Makes sense, sorry I missed that detail.
>
> Might it be better to just extend 'dmsetup targets' to take an optional
> target-name parameter? When I saw this change, I thought 'dmsetup targets
> <name>' surely worked already for the purpose, and was somewhat surprised
> when experiment disagreed. Then list_versions() has much the same code
> change as in this change, there's a little change in validate_params(),
> and it seems less surprising (to me) to extend the existing
> target-information-printing dmsetup command than to add another one.
No, I don't think it better to extend 'dmsetup targets'. There is
little to be gained in doing so.
The DM_GET_TARGET_VERSION ioctl's implementation happens to be shared
with the DM_LIST_VERSIONS ioctl (used by 'dmsetup targets') but that
doesn't imply DM_LIST_VERSIONS should be extended instead.
This is a simple change that enables userspace to accomplish a specific
goal without altering an established DM ioctl.
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