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From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [Qemu-devel] [PATCH 0/2] blockdev: Overlays are not snapshots
Date: Mon,  3 Jun 2019 18:25:10 +0200	[thread overview]
Message-ID: <20190603162512.30422-1-mreitz@redhat.com> (raw)

QEMU’s always been confused over what a snapshot is: Is it the overlay?
Is it the backing image?

Confusion is rarely a good thing.  I can’t think of any objective reason
why the overlay would be a snapshot.  A snapshot is something that does
not change over time; the overlay does.

(I suppose historically the reason is that “Taking an overlay” makes no
sense, so the operations are called “Taking a snapshot”.  Somehow, this
meaning carried over to the new file that is created during that
operation; if “Creating a snapshot” creates a file, that file must be
the snapshot, right?  Well, no, it isn’t.)

Let’s fix this as best as we can.  Better Nate than lever.


Mae Reitz (2):
  qapi/block-core: Overlays are not snapshots
  blockdev: Overlays are not snapshots

 qapi/block-core.json | 20 ++++++++++----------
 blockdev.c           | 10 +++++-----
 2 files changed, 15 insertions(+), 15 deletions(-)

-- 
2.21.0



             reply	other threads:[~2019-06-03 16:37 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03 16:25 Max Reitz [this message]
2019-06-03 16:25 ` [Qemu-devel] [PATCH 1/2] qapi/block-core: Overlays are not snapshots Max Reitz
2019-06-03 19:42   ` Eric Blake
2019-06-03 16:25 ` [Qemu-devel] [PATCH 2/2] blockdev: " Max Reitz
2019-06-03 19:42   ` Eric Blake
2019-06-03 20:07   ` Max Reitz

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