[Qemu-devel] [PATCH 0/4] qemu-img: Fix preallocation with -S 0 for convert

[Max Reitz]

Using -S 0 is supposed to allocate everything in the output image; or at
least it is supposed to always explicitly write zeros even if the area
in question is known to only contain zeros. That doesn't always work
right now, so this series fixes it (patch 1, to be specific).

I only noticed after I had written the test added by patch 4 that we
already had an -S 0 test case which is included in the iotest 122.
However, the test added here works for all image formats and is maybe
more of a direct test (instead of querying the format whether it thinks
it allocated all of the data we directly ask du whether everything has
been allocated) so maybe it reflects better what users expect -S 0 to
do. Maybe.

Patches 2 and 3 are required for the test. I could have written the test
without doing a convert with null-co as the source, but that would have
been boring, so I did not.

If you want to argue that in light of the existence of test 122 the new
test added here is unnecessary and we therefore do not need patches 2, 3
and 4, please go ahead. I won't put up too much of a fight.


Max Reitz (4):
  qemu-img: Fix preallocation with -S 0 for convert
  block/null-{co,aio}: Return zeros when read
  block/null-{co,aio}: Implement get_block_status()
  iotests: Test qemu-img convert -S 0 behavior

 block/null.c               |  19 ++++++++
 qemu-img.c                 |  37 ++++++++++------
 tests/qemu-iotests/122.out |   6 +--
 tests/qemu-iotests/146     | 105 +++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/146.out |  14 ++++++
 tests/qemu-iotests/group   |   1 +
 6 files changed, 165 insertions(+), 17 deletions(-)
 create mode 100755 tests/qemu-iotests/146
 create mode 100644 tests/qemu-iotests/146.out

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2.7.1