Re: [Qemu-devel] [PATCH 8/8] qemu-iotests: test streaming to an intermediate layer

[Eric Blake <eblake@redhat.com>]

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On 04/16/2015 09:12 AM, Alberto Garcia wrote:
> This adds test_stream_intermediate(), similar to test_stream() but
> streams to the intermediate image instead.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  tests/qemu-iotests/030     | 18 +++++++++++++++++-
>  tests/qemu-iotests/030.out |  4 ++--
>  2 files changed, 19 insertions(+), 3 deletions(-)
> 

I'm wondering if we should also test a multi-file stream.  That is,
starting from:

A <- B <- C <- D <- E

and rebasing so that A is the backing file of D (pulling both B and C
into D):

A <- D <- E

we should be able to verify that B and C are unchanged, and that D
picked up changes from both intermediate files (in particular, it's nice
to test that we aren't being inefficient by breaking the operation into
two steps: streaming B into C then C into D would give the same end
result in D, but would waste time for any clusters in B that were not
changed in C but were changed in D).

But such a test could be a separate patch, so I don't see anything wrong
with this new test as-is.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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