[Qemu-devel] [PATCH v7 00/25] qcow2: Support refcount orders != 4

[Max Reitz]

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 22 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_bits=${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.


Patches 1 to 10 are already merged to Kevin's block branch, so I omitted
them in this version.


v7:
- Patch 11: Make refcount_bits a uint64_t so it won't overflow in patch
  14 [Kevin]
- Patch 14: refcount_bits now being a uint64_t, I dropped the
  "refcount_bits <= 0" check ("== 0" is checked by is_power_of_2())
- Split the old patch 24 into patches 15 and 25 [Kevin]


git-backport-diff against v6:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

011/25:[0003] [FC] 'qcow2: refcount_order parameter for qcow2_create2'
012/25:[----] [--] 'qcow2: Use symbolic macros in qcow2_amend_options'
013/25:[----] [--] 'iotests: Prepare for refcount_bits option'
014/25:[0004] [FC] 'qcow2: Allow creation with refcount order != 4'
015/25:[0180] [FC] 'iotests: Add test for different refcount widths'
016/25:[----] [--] 'progress: Allow regressing progress'
017/25:[----] [--] 'block: Add opaque value to the amend CB'
018/25:[----] [--] 'qcow2: Use error_report() in qcow2_amend_options()'
019/25:[----] [--] 'qcow2: Use abort() instead of assert(false)'
020/25:[----] [--] 'qcow2: Split upgrade/downgrade paths for amend'
021/25:[----] [--] 'qcow2: Use intermediate helper CB for amend'
022/25:[----] [--] 'qcow2: Add function for refcount order amendment'
023/25:[----] [--] 'qcow2: Invoke refcount order amendment function'
024/25:[----] [--] 'qcow2: Point to amend function in check'
025/25:[down] 'iotests: Extend test 112 for qemu-img amend'


Max Reitz (15):
  qcow2: refcount_order parameter for qcow2_create2
  qcow2: Use symbolic macros in qcow2_amend_options
  iotests: Prepare for refcount_bits option
  qcow2: Allow creation with refcount order != 4
  iotests: Add test for different refcount widths
  progress: Allow regressing progress
  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: Extend test 112 for qemu-img amend

 block.c                          |   4 +-
 block/qcow2-cluster.c            |  14 +-
 block/qcow2-refcount.c           | 455 +++++++++++++++++++++++++++++++++++++++
 block/qcow2.c                    | 270 +++++++++++++++++------
 block/qcow2.h                    |   7 +-
 include/block/block.h            |   4 +-
 include/block/block_int.h        |   4 +-
 qemu-img.c                       |   5 +-
 tests/qemu-iotests/007           |   3 +
 tests/qemu-iotests/015           |   2 +
 tests/qemu-iotests/026           |   7 +
 tests/qemu-iotests/029           |   2 +
 tests/qemu-iotests/049.out       | 108 +++++-----
 tests/qemu-iotests/051           |   3 +
 tests/qemu-iotests/058           |   2 +
 tests/qemu-iotests/061.out       |  14 +-
 tests/qemu-iotests/067           |   2 +
 tests/qemu-iotests/079           |  10 +-
 tests/qemu-iotests/079.out       |  38 +---
 tests/qemu-iotests/080           |   2 +
 tests/qemu-iotests/082.out       |  41 +++-
 tests/qemu-iotests/085.out       |  38 ++--
 tests/qemu-iotests/089           |   2 +
 tests/qemu-iotests/108           |   2 +
 tests/qemu-iotests/112           | 296 +++++++++++++++++++++++++
 tests/qemu-iotests/112.out       | 155 +++++++++++++
 tests/qemu-iotests/common.filter |   3 +-
 tests/qemu-iotests/group         |   1 +
 util/qemu-progress.c             |   3 +-
 29 files changed, 1297 insertions(+), 200 deletions(-)
 create mode 100755 tests/qemu-iotests/112
 create mode 100644 tests/qemu-iotests/112.out

-- 
2.1.0