Re: [Qemu-devel] [PATCH v8 0/4] Improve convert and dd commands

[Max Reitz <mreitz@redhat.com>]

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On 2017-05-09 11:48, Daniel P. Berrange wrote:
> Update to
> 
>   v1: https://lists.gnu.org/archive/html/qemu-devel/2017-01/msg05699.html
>   v2: https://lists.gnu.org/archive/html/qemu-devel/2017-02/msg00728.html
>   v3: https://lists.gnu.org/archive/html/qemu-devel/2017-02/msg04391.html
>   v4: https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg02153.html
>   v5: https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg04109.html
>   v6: https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg00215.html
> 
> This series is in response to Max pointing out that you cannot
> use 'convert' for an encrypted target image.
> 
> The 'convert' and 'dd' commands need to first create the image
> and then open it. The bdrv_create() method takes a set of options
> for creating the image, which let us provide a key-secret for the
> encryption key. When the commands then open the new image, they
> don't provide any options, so the image is unable to be opened
> due to lack of encryption key. It is also not possible to use
> the --image-opts argument to provide structured options in the
> target image name - it must be a plain filename to satisfy the
> bdrv_create() API contract.
> 
> This series addresses these problems to some extent
> 
>  - Adds a new --target-image-opts flag which is used to say
>    that the target filename is using structured options.
>    It is *only* permitted to use this when -n is also set.
>    ie the target image must be pre-created so convert/dd
>    don't need to run bdrv_create().
> 
>  - When --target-image-opts is not used, add special case
>    code that identifies options passed to bdrv_create()
>    named "*key-secret" and adds them to the options used
>    to open the new image
> 
> In future it is desirable to make --target-image-opts work even when -n is
> *not* given. This requires considerable work to create a new bdrv_create()
> API impl.
> 
> The first patch fixes a bug in the 'dd' command while the second adds support
> for the missing '--object' arg to 'dd', allowing it to reference secrets when
> opening files.  The last two patches implement the new features described above
> for the 'convert' command.
> 
> NB v8 is based against git master once more, since the img_convert changes
> previously in block-next have now merged.

Changes from the previous version look good, but unfortunately here's
the "but": The image locking series has brought even more changes to
qemu-img. :-(

I tried resolving them, but the following backport-diff didn't look like
I should proceed:

001/4:[----] [-C] 'qemu-img: add support for --object with 'dd' command'
002/4:[0004] [FC] 'qemu-img: fix --image-opts usage with dd command'
003/4:[0015] [FC] 'qemu-img: introduce --target-image-opts for 'convert'
command'
004/4:[0024] [FC] 'qemu-img: copy *key-secret opts when opening newly
created files'

The fun is increased by the fact that the locking series has
(inadvertently) removed the -B documentation from convert, so there is
another conflict looming in the future...

(Or you just inadvertently add it back. Then we'd have resolved the
issue altogether...)

Max


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