From: Max Reitz <mreitz@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Kevin Wolf <kwolf@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Qemu-block <qemu-block@nongnu.org>
Subject: Re: [PATCH] block/snapshot: Clarify goto fallback behavior
Date: Fri, 4 Jun 2021 18:10:42 +0200 [thread overview]
Message-ID: <d2987f44-d1f6-88e2-123a-be9c6071b833@redhat.com> (raw)
In-Reply-To: <CAFEAcA_33PcmTSTAGGM=KGdP8Qrh-xKBdEa1d97HUhkWChzVSw@mail.gmail.com>
On 03.06.21 18:02, Peter Maydell wrote:
> On Mon, 3 May 2021 at 10:55, Max Reitz <mreitz@redhat.com> wrote:
>> In the bdrv_snapshot_goto() fallback code, we work with a pointer to
>> either bs->file or bs->backing. We close that child, close the node
>> (with .bdrv_close()), apply the snapshot on the child node, and then
>> re-open the node (with .bdrv_open()).
>>
>> In order for .bdrv_open() to attach the same child node that we had
>> before, we pass "file={child-node}" or "backing={child-node}" to it.
>> Therefore, when .bdrv_open() has returned success, we can assume that
>> bs->file or bs->backing (respectively) points to our original child
>> again. This is verified by an assertion.
>>
>> All of this is not immediately clear from a quick glance at the code,
>> so add a comment to the assertion what it is for, and why it is valid.
>> It certainly confused Coverity.
>>
>> Reported-by: Coverity (CID 1452774)
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Did this patch get lost? I was just going through outstanding
> coverity issues and noticed it was posted a month ago and not
> in master...
Oh, right, sorry. Thanks for the reminder.
Now applied to my block branch:
https://github.com/XanClic/qemu/commits/block
prev parent reply other threads:[~2021-06-04 16:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-03 9:54 [PATCH] block/snapshot: Clarify goto fallback behavior Max Reitz
2021-05-05 15:05 ` Vladimir Sementsov-Ogievskiy
2021-05-05 16:25 ` Max Reitz
2021-05-05 20:37 ` Vladimir Sementsov-Ogievskiy
2021-05-06 15:57 ` Vladimir Sementsov-Ogievskiy
2021-06-03 16:02 ` Peter Maydell
2021-06-04 16:10 ` Max Reitz [this message]
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