[Qemu-devel] [RFC 0/4] qemu-img: add max-size subcommand

[Stefan Hajnoczi]

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 subcommand that calculates the
required size for both image creation and conversion scenarios.

The conversion scenario is:

  $ qemu-img max-size -f raw -O qcow2 input.img
  107374184448

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 max-size -O qcow2 --size 5G
  196688

Stefan Hajnoczi (4):
  block: add bdrv_max_size() API
  raw-format: add bdrv_max_size() support
  qemu-img: add max-size subcommand
  iotests: add test 178 for qemu-img max-size

 include/block/block.h      |   2 +
 include/block/block_int.h  |   2 +
 block.c                    |  37 +++++++++
 block/raw-format.c         |  16 ++++
 qemu-img.c                 | 196 +++++++++++++++++++++++++++++++++++++++++++++
 qemu-img-cmds.hx           |   6 ++
 tests/qemu-iotests/178     |  75 +++++++++++++++++
 tests/qemu-iotests/178.out |  25 ++++++
 tests/qemu-iotests/group   |   1 +
 9 files changed, 360 insertions(+)
 create mode 100755 tests/qemu-iotests/178
 create mode 100644 tests/qemu-iotests/178.out

-- 
2.9.3