Notify on UNAVAIL statechange

[bitonic]

UNAVAIL is maybe not quite as concerning as DEGRADED, but still an event of notice, in my opinion. For example it is triggered when a drive goes missing.

Motivation and Context

See #12629 for the context of this change. If a drive goes missing, there are no default zedlets that send a notification.

How Has This Been Tested?

I've tested this change by modifying the notify-statechange.sh script on my machine.

This is what the email looks once this patch is applied:

Subject: ZFS device fault for pool 0xE244C57CC81BE54B on XYZ

ZFS has detected that a device was removed.

 impact: Fault tolerance of the pool may be compromised.
    eid: 20
  class: statechange
  state: UNAVAIL
   host: XYZ
   time: 2021-10-10 16:00:55+0000
  vpath: /dev/disk/by-id/ata-ST10000NM0568-2H5110_ZHZ54DBW-part1
  vguid: 0x7E580703404ED3FF
   pool: 0xE244C57CC81BE54B

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[don-brady]

Looks like the commit message is failing checkstyle. The actual code change LGTM.

[tonyhutter]

I approve, pending the commit style change

[bitonic]

Do I need to do anything? It says it's missing Signed-off-by.

[behlendorf]

@bitonic you'll need to force update this PR to include your signed-off-by in the commit message. This will resolve the style error. While you're at it I'd suggest rebasing against the latest version of the master branch as well.

https://github.com/openzfs/zfs/blob/master/.github/CONTRIBUTING.md#signed-off-by

[bitonic]

@behlendorf done.

[cbane]

This also fixes #10123. I had a nearly identical fix for that that I never got around to actually sending a pull request for.

[cholzer79]

I installed zed on my proxmox machine yesterday (apt-get install zfs-zed) and this fix was not present.
When can we expect a new build that includes this fix so that I don't have to remember altering notify-statechange.sh myself? :)