From: Mike Snitzer <snitzer@kernel.org>
To: Sarthak Kukreti <sarthakkukreti@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Joe Thornber <thornber@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Darrick J. Wong" <djwong@kernel.org>,
Jason Wang <jasowang@redhat.com>,
Bart Van Assche <bvanassche@google.com>,
Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org, Joe Thornber <ejt@redhat.com>,
linux-block@vger.kernel.org, dm-devel@redhat.com,
Andreas Dilger <adilger.kernel@dilger.ca>,
Stefan Hajnoczi <stefanha@redhat.com>,
linux-fsdevel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
linux-ext4@vger.kernel.org, Brian Foster <bfoster@redhat.com>,
Alasdair Kergon <agk@redhat.com>
Subject: Re: [PATCH v7 0/5] Introduce provisioning primitives
Date: Wed, 7 Jun 2023 19:27:24 -0400 [thread overview]
Message-ID: <ZIESXNF5anyvJEjm@redhat.com> (raw)
In-Reply-To: <CAG9=OMNv80fOyVixEY01XESnOFzYyfj9j8etHMq_Ap52z4UWNQ@mail.gmail.com>
On Mon, Jun 05 2023 at 5:14P -0400,
Sarthak Kukreti <sarthakkukreti@chromium.org> wrote:
> On Sat, Jun 3, 2023 at 8:57 AM Mike Snitzer <snitzer@kernel.org> wrote:
> >
> > We all just need to focus on your proposal and Joe's dm-thin
> > reservation design...
> >
> > [Sarthak: FYI, this implies that it doesn't really make sense to add
> > dm-thinp support before Joe's design is implemented. Otherwise we'll
> > have 2 different responses to REQ_OP_PROVISION. The one that is
> > captured in your patchset isn't adequate to properly handle ensuring
> > upper layer (like XFS) can depend on the space being available across
> > snapshot boundaries.]
> >
> Ack. Would it be premature for the rest of the series to go through
> (REQ_OP_PROVISION + support for loop and non-dm-thinp device-mapper
> targets)? I'd like to start using this as a reference to suggest
> additions to the virtio-spec for virtio-blk support and start looking
> at what an ext4 implementation would look like.
Please drop the dm-thin.c and dm-snap.c changes. dm-snap.c would need
more work to provide the type of guarantee XFS requires across
snapshot boundaries. I'm inclined to _not_ add dm-snap.c support
because it is best to just use dm-thin.
And FYI even your dm-thin patch will be the starting point for the
dm-thin support (we'll keep attribution to you for all the code in a
separate patch).
> Fair points, I certainly don't want to derail this conversation; I'd
> be happy to see this work merged sooner rather than later.
Once those dm target changes are dropped I think the rest of the
series is fine to go upstream now. Feel free to post a v8.
> For posterity, I'll distill what I said above into the following: I'd like
> a capability for userspace to create thin snapshots that ignore the
> thin volume's provisioned areas. IOW, an opt-in flag which makes
> snapshots fallback to what they do today to provide flexibility to
> userspace to decide the space requirements for the above mentioned
> scenarios, and at the same time, not adding separate corner case
> handling for filesystems. But to reiterate, my intent isn't to pile
> this onto the work you, Mike and Joe have planned; just some insight
> into why I'm in favor of ideas that reduce the snapshot size.
I think it'd be useful to ignore a thin device's reservation for
read-only snapshots. Adding the ability to create read-only thin
snapshots could make sense (later activations don't necessarily need
to impose read-only, doing so would require some additional work).
Mike
next prev parent reply other threads:[~2023-06-07 23:28 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-18 22:33 [PATCH v7 0/5] Introduce provisioning primitives Sarthak Kukreti
2023-05-18 22:33 ` [PATCH v7 1/5] block: Don't invalidate pagecache for invalid falloc modes Sarthak Kukreti
2023-05-19 4:09 ` Christoph Hellwig
2023-05-19 15:17 ` Darrick J. Wong
2023-05-18 22:33 ` [PATCH v7 2/5] block: Introduce provisioning primitives Sarthak Kukreti
2023-05-19 4:18 ` Christoph Hellwig
2023-06-09 20:00 ` Mike Snitzer
2023-05-18 22:33 ` [PATCH v7 3/5] dm: Add block provisioning support Sarthak Kukreti
2023-05-18 22:33 ` [PATCH v7 4/5] dm-thin: Add REQ_OP_PROVISION support Sarthak Kukreti
2023-05-19 15:23 ` Mike Snitzer
2023-06-08 21:24 ` Mike Snitzer
2023-06-09 0:28 ` Mike Snitzer
2023-05-18 22:33 ` [PATCH v7 5/5] loop: Add support for provision requests Sarthak Kukreti
2023-05-22 16:37 ` [dm-devel] " Darrick J. Wong
2023-05-22 22:09 ` Sarthak Kukreti
2023-05-23 1:22 ` Darrick J. Wong
2023-10-07 1:29 ` Sarthak Kukreti
2023-05-19 4:09 ` [PATCH v7 0/5] Introduce provisioning primitives Christoph Hellwig
2023-05-19 14:41 ` Mike Snitzer
2023-05-19 23:07 ` Dave Chinner
2023-05-22 18:27 ` Mike Snitzer
2023-05-23 14:05 ` Brian Foster
2023-05-23 15:26 ` Mike Snitzer
2023-05-24 0:40 ` Dave Chinner
2023-05-24 20:02 ` Mike Snitzer
2023-05-25 11:39 ` Dave Chinner
2023-05-25 16:00 ` Mike Snitzer
2023-05-25 22:47 ` Sarthak Kukreti
2023-05-26 1:36 ` Dave Chinner
2023-05-26 2:35 ` Sarthak Kukreti
2023-05-26 15:56 ` Brian Foster
2023-05-25 16:19 ` Brian Foster
2023-05-26 9:37 ` Dave Chinner
2023-05-26 15:47 ` Brian Foster
[not found] ` <CAJ0trDbspRaDKzTzTjFdPHdB9n0Q9unfu1cEk8giTWoNu3jP8g@mail.gmail.com>
2023-05-26 23:45 ` Dave Chinner
[not found] ` <CAJ0trDZJQwvAzngZLBJ1hB0XkQ1HRHQOdNQNTw9nK-U5i-0bLA@mail.gmail.com>
2023-05-30 14:02 ` Mike Snitzer
[not found] ` <CAJ0trDaUOevfiEpXasOESrLHTCcr=oz28ywJU+s+YOiuh7iWow@mail.gmail.com>
2023-05-30 15:28 ` Mike Snitzer
2023-06-02 18:44 ` Sarthak Kukreti
2023-06-02 21:50 ` Mike Snitzer
2023-06-03 0:52 ` Dave Chinner
2023-06-03 15:57 ` Mike Snitzer
2023-06-05 21:14 ` Sarthak Kukreti
2023-06-07 2:15 ` Dave Chinner
2023-06-07 23:27 ` Mike Snitzer [this message]
2023-06-09 20:31 ` Mike Snitzer
2023-06-09 21:54 ` Dave Chinner
2023-10-07 1:30 ` Sarthak Kukreti
2023-06-07 2:01 ` Dave Chinner
2023-06-07 23:50 ` Mike Snitzer
2023-06-09 3:32 ` Dave Chinner
2023-06-08 2:03 ` Martin K. Petersen
2023-06-09 0:10 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZIESXNF5anyvJEjm@redhat.com \
--to=snitzer@kernel.org \
--cc=adilger.kernel@dilger.ca \
--cc=agk@redhat.com \
--cc=axboe@kernel.dk \
--cc=bfoster@redhat.com \
--cc=bvanassche@google.com \
--cc=david@fromorbit.com \
--cc=djwong@kernel.org \
--cc=dm-devel@redhat.com \
--cc=ejt@redhat.com \
--cc=hch@infradead.org \
--cc=jasowang@redhat.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=sarthakkukreti@chromium.org \
--cc=stefanha@redhat.com \
--cc=thornber@redhat.com \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).