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Re: [Qemu-block] [PATCH for-4.0 v2 3/3] block: test block-stream with a
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From: |
Vladimir Sementsov-Ogievskiy |
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Subject: |
Re: [Qemu-block] [PATCH for-4.0 v2 3/3] block: test block-stream with a base node that is used by block-commit |
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Date: |
Fri, 29 Mar 2019 09:40:31 +0000 |
28.03.2019 19:25, Alberto Garcia wrote:
> The base node of a block-stream operation indicates the first image
> from the backing chain starting from which no data is copied to the
> top node.
>
> The block-stream job allows others to use that base image, so a second
> block-stream job could be writing to it at the same time. An important
> restriction is that the base image must not disappear while the stream
> job is ongoing. stream_start() freezes the backing chain from top to
> base with that purpose but it does it too late in the code so there is
> a race condition there.
>
> This bug was fixed in the previous commit, and this patch contains an
> iotest for this scenario.
>
> Signed-off-by: Alberto Garcia <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
--
Best regards,
Vladimir