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From:   Amir Goldstein <amir73il@gmail.com>
Date:   Tue, 18 Apr 2023 10:46:32 +0300
Message-ID: <CAOQ4uxgUOuR80jsAE2DkZhMPVNT_WwnsSX8-GSkZO4=k3VbCsw@mail.gmail.com>
Subject: Re: [Lsf-pc] [LSF TOPIC] online repair of filesystems: what next?
To:     "Darrick J. Wong" <djwong@kernel.org>
Cc:     lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org,
        xfs <linux-xfs@vger.kernel.org>,
        linux-ext4 <linux-ext4@vger.kernel.org>,
        linux-btrfs <linux-btrfs@vger.kernel.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
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On Tue, Apr 18, 2023 at 7:46=E2=80=AFAM Darrick J. Wong <djwong@kernel.org>=
 wrote:
>
> On Sat, Apr 15, 2023 at 03:18:05PM +0300, Amir Goldstein wrote:
> > On Tue, Feb 28, 2023 at 10:49=E2=80=AFPM Darrick J. Wong <djwong@kernel=
.org> wrote:
...
> > Darrick,
> >
> > Quick question.
> > You indicated that you would like to discuss the topics:
> > Atomic file contents exchange
> > Atomic directio writes
>
> This one ^^^^^^^^ topic should still get its own session, ideally with
> Martin Petersen and John Garry running it.  A few cloud vendors'
> software defined storage stacks can support multi-lba atomic writes, and
> some database software could take advantage of that to reduce nested WAL
> overhead.
>

CC Martin.
If you want to lead this session, please schedule it.

> > Are those intended to be in a separate session from online fsck?
> > Both in the same session?
> >
> > I know you posted patches for FIEXCHANGE_RANGE [1],
> > but they were hiding inside a huge DELUGE and people
> > were on New Years holidays, so nobody commented.
>
> After 3 years of sparse review comments, I decided to withdraw
> FIEXCHANGE_RANGE from general consideration after realizing that very
> few filesystems actually have the infrastructure to support atomic file
> contents exchange, hence there's little to be gained from undertaking
> fsdevel bikeshedding.
>
> > Perhaps you should consider posting an uptodate
> > topic suggestion to let people have an opportunity to
> > start a discussion before LSFMM.
>
> TBH, most of my fs complaints these days are managerial problems (Are we
> spending too much time on LTS?  How on earth do we prioritize projects
> with all these drive by bots??  Why can't we support large engineering
> efforts better???) than technical.

I penciled one session for "FS stable backporting (and other LTS woes)".
I made it a cross FS/IO session so we can have this session in the big room
and you are welcome to pull this discussion to any direction you want.

>
> (I /am/ willing to have a "Online fs metadata reconstruction: How does
> it work, and can I have some of what you're smoking?" BOF tho)
>

I penciled a session for this one already.
Maybe it would be interesting for the crowd to hear some about
"behind the scenes" - how hard it was and still is to pull off an
engineering project of this scale - lessons learned, things that
you might have done differently.

Cheers,
Amir.