[PATCH v4 00/35] block: publish backup-top filter

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Hi all!

v4: rebase on Kevin's block branch
v3: Keep x-perf.copy-range backup option.

So, additional function is added to set copy_range in block-copy after creation.
And if we do so, it's better to set "compress" option same way instead of handling
x-deprecated-compress option.

8: rebased on not yet remove @perf argument, keep r-b
11, 21, 23: small related rebase conflicts, keep r-b
9, 10, 19: new
20: drop x-deprecated-compress option, drop r-b
24: fix typo
34: fix qmp( , **{}) to qmp( , {})

also, add a lot of Max's r-bs, thanks!!!

So, patches without r-b: 9, 10, 19, 20

v2:
01-02: new
03: don't bother with supporting empty child: we should never have such
    at this point
05: add comment
06: keep checking conflict with global
    add realized_set_allowed to qdev_prop_drive_iothread
07: improve cbw_cbw() name
    improve commit message
10: rebased on unchanged backup_calculate_cluster_size(). keep r-b  CHECK ME
12: new
13: drop extra bdrv_unref()
18: add compress local variable
    add comment about x-deprecated-compress
19: new, replacement for "[PATCH 17/21] block/block-copy: switch to fully set bitmap by default"
22: improve qapi documentation
23-33: test: a lot of refactoring

We have image fleecing scheme to export point-in-time state of active
disk (iotest 222):


                                      backup(sync=none)
                     ┌───────────────────────────────────────┐
                     ▼                                       │
┌────────────┐     ┌────────────────┐  backing             ┌─────────────┐
│ NBD export │ ─── │ temp qcow2 img │ ───────────────────▶ │ active disk │
└────────────┘     └────────────────┘                      └─────────────┘
                                                             ▲
┌────────────┐                                               │
│ guest blk  │ ──────────────────────────────────────────────┘
└────────────┘                        


Actually, backup job inserts a backup-top filter, so in detail it looks
like:

                                      backup(sync=none)
                     ┌───────────────────────────────────────┐
                     ▼                                       │
┌────────────┐     ┌────────────────┐  backing             ┌─────────────┐
│ NBD export │ ─── │ temp qcow2 img │ ───────────────────▶ │ active disk │
└────────────┘     └────────────────┘                      └─────────────┘
                     ▲                                       ▲
                     │ target                                │
                     │                                       │
┌────────────┐     ┌────────────────┐  backing               │
│ guest blk  │ ──▶ │   backup-top   │ ───────────────────────┘
└────────────┘     └────────────────┘

And job does nothing here. In a new blockdev world user is intended to
operate on node level, and insert/remove filters by hand. Let's get rid
of job in the scheme:

┌────────────┐     ┌────────────────┐  backing             ┌─────────────┐
│ NBD export │ ─── │ temp qcow2 img │ ───────────────────▶ │ active disk │
└────────────┘     └────────────────┘                      └─────────────┘
                     ▲                                       ▲
                     │ target                                │
                     │                                       │
┌────────────┐     ┌────────────────┐  backing               │
│ guest blk  │ ──▶ │   backup-top   │ ───────────────────────┘
└────────────┘     └────────────────┘


The series prepares qom-set to make possible inserting filters above
root node (patches 03-06), rename backup-top to copy-before-write, do
other preparations for publishing the filter, and finally publish it,
add qapi interface and test new fleecing scheme in 222 (first, some
good test refactoring).

Vladimir Sementsov-Ogievskiy (35):
  block: rename bdrv_replace_child to bdrv_replace_child_tran
  block: comment graph-modifying function not updating permissions
  block: introduce bdrv_replace_child_bs()
  block: introduce blk_replace_bs
  qdev-properties: PropertyInfo: add realized_set_allowed field
  qdev: allow setting drive property for realized device
  block: rename backup-top to copy-before-write
  block-copy: always set BDRV_REQ_SERIALISING flag
  block/block-copy: introduce block_copy_set_copy_opts()
  block/backup: set copy_range and compress after filter insertion
  block/backup: move cluster size calculation to block-copy
  block/copy-before-write: relax permission requirements when no parents
  block/copy-before-write: drop extra bdrv_unref on failure path
  block/copy-before-write: use file child instead of backing
  block/copy-before-write: bdrv_cbw_append(): replace child at last
  block/copy-before-write: introduce cbw_init()
  block/copy-before-write: cbw_init(): rename variables
  block/copy-before-write: cbw_init(): use file child after attaching
  block/copy-before-write: bdrv_cbw_append(): drop unused compress arg
  block/copy-before-write: cbw_init(): use options
  block/copy-before-write: initialize block-copy bitmap
  block/block-copy: make setting progress optional
  block/copy-before-write: make public block driver
  qapi: publish copy-before-write filter
  python/qemu/machine.py: refactor _qemu_args()
  python/qemu/machine: QEMUMachine: improve qmp() method
  iotests.py: VM: add own __enter__ method
  iotests/222: fix pylint and mypy complains
  iotests/222: constantly use single quotes for strings
  iotests: move 222 to tests/image-fleecing
  iotests.py: hmp_qemu_io: support qdev
  iotests/image-fleecing: proper source device
  iotests/image-fleecing: rename tgt_node
  iotests/image-fleecing: prepare for adding new test-case
  iotests/image-fleecing: add test-case for copy-before-write filter

 qapi/block-core.json                        |  30 ++-
 block/{backup-top.h => copy-before-write.h} |  25 +-
 include/block/block-copy.h                  |   6 +-
 include/block/block.h                       |   2 +
 include/hw/qdev-properties.h                |   1 +
 include/sysemu/block-backend.h              |   1 +
 block.c                                     |  53 +++-
 block/backup-top.c                          | 253 -------------------
 block/backup.c                              | 116 ++-------
 block/block-backend.c                       |   8 +
 block/block-copy.c                          | 148 ++++++++---
 block/copy-before-write.c                   | 256 ++++++++++++++++++++
 hw/core/qdev-properties-system.c            |  43 +++-
 hw/core/qdev-properties.c                   |   6 +-
 MAINTAINERS                                 |   4 +-
 block/meson.build                           |   2 +-
 python/qemu/machine.py                      |  30 ++-
 tests/qemu-iotests/222                      | 159 ------------
 tests/qemu-iotests/222.out                  |  67 -----
 tests/qemu-iotests/283                      |  35 ++-
 tests/qemu-iotests/283.out                  |   4 +-
 tests/qemu-iotests/297                      |   2 +-
 tests/qemu-iotests/iotests.py               |   9 +-
 tests/qemu-iotests/tests/image-fleecing     | 192 +++++++++++++++
 tests/qemu-iotests/tests/image-fleecing.out | 139 +++++++++++
 25 files changed, 911 insertions(+), 680 deletions(-)
 rename block/{backup-top.h => copy-before-write.h} (56%)
 delete mode 100644 block/backup-top.c
 create mode 100644 block/copy-before-write.c
 delete mode 100755 tests/qemu-iotests/222
 delete mode 100644 tests/qemu-iotests/222.out
 create mode 100755 tests/qemu-iotests/tests/image-fleecing
 create mode 100644 tests/qemu-iotests/tests/image-fleecing.out

-- 
2.29.2