[RFC PATCH v2 00/26] Add subcluster allocation to qcow2

[Alberto Garcia]

Hi,

here's the new version of the patches to add subcluster allocation
support to qcow2.

Please refer to the cover letter of the first version for a full
description of the patches:

   https://lists.gnu.org/archive/html/qemu-block/2019-10/msg00983.html

This version includes a few tests, but I'm planning to add more for
the next revision.

Berto

v2:
- Patch 12: Update after the changes in 88f468e546.
- Patch 21 (new): Clear the L2 bitmap when allocating a compressed
  cluster. Compressed clusters should have the bitmap all set to 0.
- Patch 24: Document the new fields in the QAPI documentation [Eric].
- Patch 25: Allow qcow2 preallocation with backing files.
- Patch 26: Add some tests for qcow2 images with extended L2 entries.

v1: https://lists.gnu.org/archive/html/qemu-block/2019-10/msg00983.html

Output of git backport-diff against v1:

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

001/26:[----] [-C] 'qcow2: Add calculate_l2_meta()'
002/26:[----] [--] 'qcow2: Split cluster_needs_cow() out of 
count_cow_clusters()'
003/26:[----] [--] 'qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in 
handle_copied()'
004/26:[----] [--] 'qcow2: Add get_l2_entry() and set_l2_entry()'
005/26:[----] [--] 'qcow2: Document the Extended L2 Entries feature'
006/26:[----] [--] 'qcow2: Add dummy has_subclusters() function'
007/26:[----] [--] 'qcow2: Add subcluster-related fields to BDRVQcow2State'
008/26:[----] [--] 'qcow2: Add offset_to_sc_index()'
009/26:[----] [--] 'qcow2: Add l2_entry_size()'
010/26:[----] [--] 'qcow2: Update get/set_l2_entry() and add 
get/set_l2_bitmap()'
011/26:[----] [--] 'qcow2: Add qcow2_get_subcluster_type()'
012/26:[0005] [FC] 'qcow2: Handle QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER'
013/26:[----] [--] 'qcow2: Add subcluster support to calculate_l2_meta()'
014/26:[----] [--] 'qcow2: Add subcluster support to qcow2_get_cluster_offset()'
015/26:[----] [--] 'qcow2: Add subcluster support to zero_in_l2_slice()'
016/26:[----] [--] 'qcow2: Add subcluster support to discard_in_l2_slice()'
017/26:[----] [--] 'qcow2: Add subcluster support to check_refcounts_l2()'
018/26:[----] [--] 'qcow2: Add subcluster support to 
expand_zero_clusters_in_l1()'
019/26:[----] [--] 'qcow2: Fix offset calculation in handle_dependencies()'
020/26:[----] [--] 'qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2()'
021/26:[down] 'qcow2: Clear the L2 bitmap when allocating a compressed cluster'
022/26:[----] [--] 'qcow2: Add subcluster support to handle_alloc_space()'
023/26:[----] [--] 'qcow2: Restrict qcow2_co_pwrite_zeroes() to full clusters 
only'
024/26:[0007] [FC] 'qcow2: Add the 'extended_l2' option and the 
QCOW2_INCOMPAT_EXTL2 bit'
025/26:[down] 'qcow2: Allow preallocation and backing files if extended_l2 is 
set'
026/26:[down] 'iotests: Add tests for qcow2 images with extended L2 entries'

Alberto Garcia (26):
  qcow2: Add calculate_l2_meta()
  qcow2: Split cluster_needs_cow() out of count_cow_clusters()
  qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied()
  qcow2: Add get_l2_entry() and set_l2_entry()
  qcow2: Document the Extended L2 Entries feature
  qcow2: Add dummy has_subclusters() function
  qcow2: Add subcluster-related fields to BDRVQcow2State
  qcow2: Add offset_to_sc_index()
  qcow2: Add l2_entry_size()
  qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap()
  qcow2: Add qcow2_get_subcluster_type()
  qcow2: Handle QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER
  qcow2: Add subcluster support to calculate_l2_meta()
  qcow2: Add subcluster support to qcow2_get_cluster_offset()
  qcow2: Add subcluster support to zero_in_l2_slice()
  qcow2: Add subcluster support to discard_in_l2_slice()
  qcow2: Add subcluster support to check_refcounts_l2()
  qcow2: Add subcluster support to expand_zero_clusters_in_l1()
  qcow2: Fix offset calculation in handle_dependencies()
  qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2()
  qcow2: Clear the L2 bitmap when allocating a compressed cluster
  qcow2: Add subcluster support to handle_alloc_space()
  qcow2: Restrict qcow2_co_pwrite_zeroes() to full clusters only
  qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit
  qcow2: Allow preallocation and backing files if extended_l2 is set
  iotests: Add tests for qcow2 images with extended L2 entries

 block/qcow2-cluster.c            | 548 ++++++++++++++++++++-----------
 block/qcow2-refcount.c           |  38 ++-
 block/qcow2.c                    |  92 +++++-
 block/qcow2.h                    | 121 ++++++-
 docs/interop/qcow2.txt           |  68 +++-
 docs/qcow2-cache.txt             |  19 +-
 include/block/block_int.h        |   1 +
 qapi/block-core.json             |   6 +
 tests/qemu-iotests/031.out       |   8 +-
 tests/qemu-iotests/036.out       |   4 +-
 tests/qemu-iotests/049.out       | 102 +++---
 tests/qemu-iotests/060.out       |   1 +
 tests/qemu-iotests/061.out       |  20 +-
 tests/qemu-iotests/065           |  18 +-
 tests/qemu-iotests/082.out       |  48 ++-
 tests/qemu-iotests/085.out       |  38 +--
 tests/qemu-iotests/144.out       |   4 +-
 tests/qemu-iotests/182.out       |   2 +-
 tests/qemu-iotests/185.out       |   8 +-
 tests/qemu-iotests/198.out       |   2 +
 tests/qemu-iotests/206.out       |   6 +-
 tests/qemu-iotests/242.out       |   5 +
 tests/qemu-iotests/255.out       |   8 +-
 tests/qemu-iotests/271           | 235 +++++++++++++
 tests/qemu-iotests/271.out       | 183 +++++++++++
 tests/qemu-iotests/common.filter |   1 +
 tests/qemu-iotests/group         |   1 +
 27 files changed, 1247 insertions(+), 340 deletions(-)
 create mode 100755 tests/qemu-iotests/271
 create mode 100644 tests/qemu-iotests/271.out

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2.20.1