Re: [NYE DELUGE 1/4] xfs: all pending online scrub improvements

[Zorro Lang <zlang@redhat.com>]

On Fri, Dec 30, 2022 at 01:13:21PM -0800, Darrick J. Wong wrote:
> Hi everyone,
> 
> As I've mentioned several times throughout 2022, I would like to merge
> the online fsck feature in time for the 2023 LTS kernel.  The first big
> step in this process is to merge all the pending bug fixes, validation
> improvements, and general reorganization of the existing metadata
> scrubbing functionality.
> 
> This first deluge starts with the design document for the entirety of
> the online fsck feature.  The design doc should be familiar to most of
> you, as it's been on the list for review for months already.  It
> outlines in brief the problems we're trying to solve, the use cases and
> testing plan, and the fundamental data structures and algorithms
> underlying the entire feature.
> 
> After that come all the code changes to wrap up the metadata checking
> part of the feature.  The biggest piece here is the scrub drains that
> allow scrub to quiesce deferred ops targeting AGs so that it can
> cross-reference recordsets.  Most of the rest is tweaking the btree code
> so that we can do keyspace scans to look for conflicting records.
> 
> For this review, I would like people to focus the following:
> 
> - Are the major subsystems sufficiently documented that you could figure
>   out what the code does?
> 
> - Do you see any problems that are severe enough to cause long term
>   support hassles? (e.g. bad API design, writing weird metadata to disk)
> 
> - Can you spot mis-interactions between the subsystems?
> 
> - What were my blind spots in devising this feature?
> 
> - Are there missing pieces that you'd like to help build?
> 
> - Can I just merge all of this?
> 
> The one thing that is /not/ in scope for this review are requests for
> more refactoring of existing subsystems.  While there are usually valid
> arguments for performing such cleanups, those are separate tasks to be
> prioritized separately.  I will get to them after merging online fsck.
> 
> I've been running daily online scrubs of every computer I own for the
> last five years, which has helped me iron out real problems in (limited
> scope) production.  All issues observed in that time have been corrected
> in this submission.

The 3 fstests patchsets of the [NYE DELUGE 1/4] look good to me. And I didn't
find more critical issues after Darrick fixed that "group name missing" problem.
By testing it a whole week, I decide to merge this 3 patchsets this weekend,
then we can shift to later patchsets are waiting for review and merge.

Reviewed-by: Zorro Lang <zlang@redhat.com>

Thanks,
Zorro

> 
> As a warning, the patches will likely take several days to trickle in.
> All four patch deluges are based off kernel 6.2-rc1, xfsprogs 6.1, and
> fstests 2022-12-25.
> 
> Thank you all for your participation in the XFS community.  Have a safe
> New Years, and I'll see you all next year!
> 
> --D
>