[v1] blockdev: Overlays are not snapshots

[Qemu-devel] [PATCH 0/2] blockdev: Overlays are not snapshots

Max Reitz posted 2 patches 4 years, 10 months ago

Diff against v2
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Test docker-mingw@fedora passed

Test docker-clang@ubuntu passed

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git fetch https://github.com/patchew-project/qemu tags/patchew/20190603162512.30422-1-mreitz@redhat.com

Maintainers: Max Reitz <mreitz@redhat.com>, Markus Armbruster <armbru@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Eric Blake <eblake@redhat.com>

There is a newer version of this series

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

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[Qemu-devel] [PATCH 0/2] blockdev: Overlays are not snapshots

Posted by Max Reitz 4 years, 10 months ago

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