zpool.present: correctly handle "feature@" properties

[asomers]

Optional ZFS pool features can have three states: disabled, enabled, and
active. Enabled means that ZFS will use them if it needs them, but they
haven't changed the on-disk format yet, so they can still be switched
off. But active features have already changed the on-disk format, so
they can't be switched off. Disabled features may not be used.

When enabling such a feature via the zpool.present state, treat "active"
as identical to "enabled".

Fixes #62390

What does this PR do?

Treats zpool properties named "feature@XXX" as being "enabled" if they are really "active" during the zpool.present state.

What issues does this PR fix or reference?

Fixes: 62390

Previous Behavior

If a zpool.present state tried to set a feature to enabled, but that feature was already active on the pool, then Salt would redundantly execute zpool set again, to no effect.

New Behavior

Such a state won't result in any action being taken.

Merge requirements satisfied?

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

[Ch3LL]

Can you help my understanding with this fix:

• If you want the status to be active wouldn't you just set active in the state instead of "enabled"?
• I'm worried this would change expected behavior because it is changing the status from what the user set in the state.

[asomers]

Can you help my understanding with this fix:

* If you want the status to be active wouldn't you just set `active` in the state instead of "enabled"?

No. "enabled" means that the pool feature is enabled but ZFS isn't using it yet. An "enabled" feature can be reset back to "disabled" if you want to. But an "active" feature means that ZFS is already using it, so you cannot disable it. For example, you might set the feature@edonr feature to "enabled". But it won't become active until you actually set checksum=edonr for some dataset. It isn't possible to explicitly set the feature to "active" with a command like zpool set feature@edonr=active tank.

* I'm worried this would change expected behavior because it is changing the status from what the user set in the state.

The original behavior was clearly a bug, because Salt would try to enable an active feature over and over, on every state application, to no effect.

[Ch3LL]

Thanks for explaining. Makes sense now