Zfs: Add file to keep track of feature additions / removals / changes as per leadership meeting

[mcdonc]

As per discussion in "semantic versioning" part of the leadership meeting (i think) recorded at https://www.youtube.com/watch?v=OpvyKVjHEFE, we would like to create a top-level file that can be used by individual developers that would allow them to create a human consumable description of a feature they've added or changed. At release time, this file would be used to compile the release notes. I heard it mentioned that this file may be called "NEWS" although we already have that file (not much in there).

[mcdonc]

Via Slack @ahrens said:

I think the next step is for someone to compile a list of new features that are in master but not 0.8, and open a PR to add that file to the repo.

[ahrens]

Here's a running list that I have. Not sure which of these are in 0.8 or not, I have it by year (including conferences where it was presented, may be useful for linking to presentations). This isn't meant to be comprehensive, there are probably many smaller features or changes that we'd also want to mention.

2018

• Device removal (January) (OZDS 2014, User Conf 2017, BSDCAN 2018)
• Project accounting/quota (February)
• Zpool checkpoint (March) (OZDS 2017)
• Zpool initialize (April) (OZDS 2015)
• Special devices for metadata (September) (OZDS 2015)

2019

• TRIM (March) - to ZoL (OZDS 2019)
• Encryption (June) - to illumos
• Redacted send/receive (June) (OZDS 2015)
• Spacemap log (July) (OZDS 2017)
• Fast clone deletion (July) (OZDS 2017, BSDCAN 2018)
• zpool wait (September)

2020

• Saved send (Jan)
• Zpool wait trim (March)
• FreeBSD & Linux support in common repo (April)
• Zfs wait delete (April)
• Persistent L2ARC (April)
• Zstream redup, remove dedup code (April)
• Sequential Rebuild (July)

[behlendorf]

The major features which were included in 0.8 are listed in the GitHub release notes. All of the major new 2.0 features should be listed in the OpenZFS 2.0 project. However, we're going to need to go through the commit history to identify noteworthy smaller changes.

[Ornias1993]

There are some solutions to use Tags in a PR to automagically add changes to a release notes files, I think such a solution is the most efficient way of going about this.

edit 1
I looked into this some more:
Some systems of auto-generating are based on the PR description, those won't work.
We need something that fetches special tags from commits and creates a changelog.

edit 2
While it would be HELL to implement fully, I think a system like this might check all the boxes:
https://github.com/semantic-release/semantic-release

• Able to generate release notes from changelogs
• Based on commits, not PR descriptions
• Should be able to handle backports
• Also enforces actual semantic versioning