Re: [Qemu-devel] [PATCH v3 0/8] qemu-img: add measure sub-command

[Nir Soffer <nsoffer@redhat.com>]

On Wed, Mar 22, 2017 at 2:28 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:

> v3:
>  * Drop RFC, this is ready to go for QEMU 2.10
>  * Use "required size" instead of "required bytes" in qemu-img output for
>    consistency [Nir]
>  * Clarify BlockMeasureInfo semantics [Max]
>  * Clarify bdrv_measure() opts argument and error handling [Nir]
>  * Handle -o backing_file= for qcow2 [Max]
>  * Handle snapshot options in qemu-img measure
>  * Probe input image for allocated data clusters for qcow2.  Didn't
> centralize
>    this because there are format-specific aspects such as the
> cluster_size.  It
>    may make sense to centralize it later (with a bit more complexity) if
>    support is added to more formats.
>  * Add qemu-img(1) man page section for 'measure' sub-command [Max]
>  * Extend test case to cover additional scenarios [Nir]
>
> RFCv2:
>  * Publishing RFC again to discuss the new user-visible interfaces.  Code
> has
>    changed quite a bit, I have not kept any Reviewed-by tags.
>  * Rename qemu-img sub-command "measure" and API bdrv_measure() [Nir]
>  * Report both "required bytes" and "fully allocated bytes" to handle the
> empty
>    image file and prealloc use cases [Nir and Dan]
>  * Use bdrv_getlength() instead of bdrv_nb_sectors() [Berto]
>  * Rename "err" label "out" in qemu-img-cmds.c [Nir]
>  * Add basic qcow2 support, doesn't support qemu-img convert from existing
> files yet
>
> RFCv1:
>  * Publishing patch series with just raw support, no qcow2 yet.  Please
> review
>    the command-line interface and let me know if you are happy with this
>    approach.
>
> Users and management tools sometimes need to know the size required for a
> new
> disk image so that an LVM volume, SAN LUN, etc can be allocated ahead of
> time.
> Image formats like qcow2 have non-trivial metadata that makes it hard to
> estimate the exact size without knowledge of file format internals.
>
> This patch series introduces a new qemu-img sub-command that calculates the
> required size for both image creation and conversion scenarios.
>
> The conversion scenario is:
>
>   $ qemu-img measure -f raw -O qcow2 input.img
>   required size: 1327680
>   fully allocated size: 1074069504
>
> Here an existing image file is taken and the output includes the space
> required
> for data from the input image file.
>
> The creation scenario is:
>
>   $ qemu-img measure -O qcow2 --size 5G
>   required size: 327680
>   fully allocated size: 1074069504
>
> Stefan Hajnoczi (8):
>   block: add bdrv_measure() API
>   raw-format: add bdrv_measure() support
>   qcow2: extract preallocation calculation function
>   qcow2: extract image creation option parsing
>   qcow2: add bdrv_measure() support
>   qemu-img: add measure subcommand
>   qemu-iotests: support per-format golden output files
>   iotests: add test 178 for qemu-img measure
>
>  qapi/block-core.json             |  25 +++
>  include/block/block.h            |   4 +
>  include/block/block_int.h        |   2 +
>  block.c                          |  35 ++++
>  block/qcow2.c                    | 362
> +++++++++++++++++++++++++++++----------
>  block/raw-format.c               |  22 +++
>  qemu-img.c                       | 227 ++++++++++++++++++++++++
>  qemu-img-cmds.hx                 |   6 +
>  qemu-img.texi                    |  25 +++
>  tests/qemu-iotests/178           | 144 ++++++++++++++++
>  tests/qemu-iotests/178.out.qcow2 | 242 ++++++++++++++++++++++++++
>  tests/qemu-iotests/178.out.raw   | 130 ++++++++++++++
>  tests/qemu-iotests/check         |   5 +
>  tests/qemu-iotests/group         |   1 +
>  14 files changed, 1136 insertions(+), 94 deletions(-)
>  create mode 100755 tests/qemu-iotests/178
>  create mode 100644 tests/qemu-iotests/178.out.qcow2
>  create mode 100644 tests/qemu-iotests/178.out.raw
>
> --
> 2.9.3
>

Stefan, is this available in some public git repo?

I would like to test it,  and downloading and applying 8 patches is lot of
work.
(I'm probably not using the right tools for this).

Nir