From: Eric Blake <eblake@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>, qemu-block@nongnu.org
Cc: vsementsov@virtuozzo.com, jsnow@redhat.com,
qemu-devel@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH 2/3] mirror: Make sure that source and target size match
Date: Thu, 7 May 2020 10:13:29 -0500 [thread overview]
Message-ID: <fde78263-d1f8-6f3b-ec9c-f8527194c9a9@redhat.com> (raw)
In-Reply-To: <20200507145228.323412-3-kwolf@redhat.com>
On 5/7/20 9:52 AM, Kevin Wolf wrote:
> If the target is shorter than the source, mirror would copy data until
> it reaches the end of the target and then fail with an I/O error when
> trying to write past the end.
>
> If the target is longer than the source, the mirror job would complete
> successfully, but the target wouldn't actually be an accurate copy of
> the source image (it would contain some additional garbage at the end).
>
> Fix this by checking that both images have the same size when the job
> starts.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> block/mirror.c | 21 ++++++++++++---------
> 1 file changed, 12 insertions(+), 9 deletions(-)
An alternative would be trying to resize the target (like we have to do
with active commit), but I'm fine with being conservative for now by
forcing the user to have correct sizing, where we have the option to add
magic resizing later only if it proves useful and not introducing more
potential issues.
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
next prev parent reply other threads:[~2020-05-07 15:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 14:52 [PATCH 0/3] mirror: Make sure that source and target size match Kevin Wolf
2020-05-07 14:52 ` [PATCH 1/3] iotests/229: Use blkdebug to inject an error Kevin Wolf
2020-05-07 15:09 ` Eric Blake
2020-05-07 14:52 ` [PATCH 2/3] mirror: Make sure that source and target size match Kevin Wolf
2020-05-07 15:13 ` Eric Blake [this message]
2020-05-07 14:52 ` [PATCH 3/3] iotests: Mirror with different source/target size Kevin Wolf
2020-05-07 15:16 ` Eric Blake
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