[Qemu-devel] [PATCH 00/21] qcow2: Support refcount orders != 4

[Max Reitz <mreitz@redhat.com>]

This should not need much of a cover letter, but here goes anyway:

As of version 3, the qcow2 file format supports different widths for
refcount entries, ranging from 1 to 64 bit (only powers of two).
Currently, qemu only supports 16 bit, which is the only width supported
by version 2 (compat=0.10) images.

This series adds support to qemu for all other valid refcount orders.
This is mainly done by adding two function pointers into the
BDRVQcowState structure for reading and writing refcount values
independently of the current refcount entry width; all in-memory
refcount arrays (mostly cached refcount blocks) now are void pointers
and are accessed through these functions alone.

Thanks to previous work of making the qemu code agnostic of e.g. the
number of refcount entries per refcount block, the rest is fairly
trivial. The most complex patch in this series is patch 18 which
implements changing the refcount order through qemu-img amend.

To test different refcount widths, simply invoke the qemu-iotests check
program with -o refcount_width=${your_desired_width}. The final test in
this series adds some tests for operations which do not work with
certain refcount orders and for refcount order amendment.


Max Reitz (21):
  qcow2: Add two new fields to BDRVQcowState
  qcow2: Add refcount_width to format-specific info
  qcow2: Use 64 bits for refcount values
  qcow2: Respect error in qcow2_alloc_bytes()
  qcow2: Refcount overflow and qcow2_alloc_bytes()
  qcow2: Helper function for refcount modification
  qcow2: Helper for refcount array size calculation
  qcow2: More helpers for refcount modification
  qcow2: Open images with refcount order != 4
  qcow2: refcount_order parameter for qcow2_create2
  iotests: Prepare for refcount_width option
  qcow2: Allow creation with refcount order != 4
  block: Add opaque value to the amend CB
  qcow2: Use error_report() in qcow2_amend_options()
  qcow2: Use abort() instead of assert(false)
  qcow2: Split upgrade/downgrade paths for amend
  qcow2: Use intermediate helper CB for amend
  qcow2: Add function for refcount order amendment
  qcow2: Invoke refcount order amendment function
  qcow2: Point to amend function in check
  iotests: Add test for different refcount widths

 block.c                          |   4 +-
 block/qcow2-cluster.c            |  23 +-
 block/qcow2-refcount.c           | 846 ++++++++++++++++++++++++++++++++++-----
 block/qcow2.c                    | 252 +++++++++---
 block/qcow2.h                    |  24 +-
 include/block/block.h            |   4 +-
 include/block/block_int.h        |   4 +-
 qapi/block-core.json             |   5 +-
 qemu-img.c                       |   5 +-
 tests/qemu-iotests/007           |   4 +
 tests/qemu-iotests/015           |   1 +
 tests/qemu-iotests/026           |  11 +
 tests/qemu-iotests/029           |   1 +
 tests/qemu-iotests/049.out       | 112 +++---
 tests/qemu-iotests/051           |   1 +
 tests/qemu-iotests/058           |   1 +
 tests/qemu-iotests/060.out       |   1 +
 tests/qemu-iotests/061.out       |  14 +-
 tests/qemu-iotests/065           |  23 +-
 tests/qemu-iotests/067           |   7 +
 tests/qemu-iotests/067.out       |  10 +-
 tests/qemu-iotests/079           |   1 +
 tests/qemu-iotests/079.out       |  18 +-
 tests/qemu-iotests/080           |   1 +
 tests/qemu-iotests/082.out       |  48 ++-
 tests/qemu-iotests/085.out       |  38 +-
 tests/qemu-iotests/089           |   7 +
 tests/qemu-iotests/089.out       |   2 +
 tests/qemu-iotests/090           |   1 +
 tests/qemu-iotests/108           |   6 +
 tests/qemu-iotests/112           | 225 +++++++++++
 tests/qemu-iotests/112.out       | 123 ++++++
 tests/qemu-iotests/common.filter |   3 +-
 tests/qemu-iotests/group         |   1 +
 34 files changed, 1546 insertions(+), 281 deletions(-)
 create mode 100755 tests/qemu-iotests/112
 create mode 100644 tests/qemu-iotests/112.out

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1.9.3