[Qemu-block] [PATCH v6 00/16] backup compression

[Denis V. Lunev]

The idea is simple - backup is "written-once" data. It is written block
by block and it is large enough. It would be nice to save storage
space and compress it.

These patches add the ability to compress data during backup. This
functionality is implemented by means of adding options to the qmp/hmp
commands(drive-backup, blockdev-backup). The implementation is quite
simple, because the responsibility for data compression imposed on the
format driver.

Changes from v1:
- added unittest for backup compression (12, 13)

Changes from v2:
- implemented a new .bdrv_co_write_compressed interface to replace the
  old .bdrv_write_compressed (2,3,4,5,6)

Changes from v3:
- added the byte-based interfaces:
  blk_pwrite_compressed()/blk_co_pwritev_compressed() (1, 7)
- fix drive/blockdev-backup documentation (10, 11)

Changes form v4:
- added assert that offset and count are aligned (1)
- reuse RwCo and bdrv_co_pwritev() for write compressed (2)
- converted interfaces to byte-based for format drivers (2, 3, 5, 6)
- move an unrelated cleanup in a separate patches (4, 7)
- turn on dirty_bitmaps for the compressed writes (9)
- added simplify drive/blockdev-backup by using the boxed commands (10, 11)
- reworded drive/blockdev-backup documentation about compression (12, 13)
- fix s/bakup/backup/ (14)

Changes form v5:
- rebased on master
- fix grammar (5, 8)

Signed-off-by: Pavel Butsykin <address@hidden>
Signed-off-by: Denis V. Lunev <address@hidden>
CC: Jeff Cody <address@hidden>
CC: Markus Armbruster <address@hidden>
CC: Eric Blake <address@hidden>
CC: John Snow <address@hidden>
CC: Stefan Hajnoczi <address@hidden>
CC: Kevin Wolf <address@hidden>

Pavel Butsykin (16):
  block: switch blk_write_compressed() to byte-based interface
  block: Convert bdrv_pwrite_compressed() to BdrvChild
  block/io: reuse bdrv_co_pwritev() for write compressed
  qcow2: add qcow2_co_pwritev_compressed
  qcow2: cleanup qcow2_co_pwritev_compressed to avoid the recursion
  vmdk: add vmdk_co_pwritev_compressed
  qcow: add qcow_co_pwritev_compressed
  qcow: cleanup qcow_co_pwritev_compressed to avoid the recursion
  block: remove BlockDriver.bdrv_write_compressed
  block/io: turn on dirty_bitmaps for the compressed writes
  block: simplify drive-backup
  block: simplify blockdev-backup
  drive-backup: added support for data compression
  blockdev-backup: added support for data compression
  qemu-iotests: test backup compression in 055
  qemu-iotests: add vmdk for test backup compression in 055

 block/backup.c                 |  12 ++-
 block/block-backend.c          |  27 +-----
 block/io.c                     |  48 ++++------
 block/qcow.c                   | 113 +++++++++---------------
 block/qcow2.c                  | 128 ++++++++++-----------------
 block/vmdk.c                   |  55 ++----------
 blockdev.c                     | 193 ++++++++++++++---------------------------
 hmp-commands.hx                |   8 +-
 hmp.c                          |  32 ++++---
 include/block/block.h          |   5 +-
 include/block/block_int.h      |   5 +-
 include/sysemu/block-backend.h |   4 +-
 qapi/block-core.json           |  18 +++-
 qemu-img.c                     |   8 +-
 qemu-io-cmds.c                 |   2 +-
 qmp-commands.hx                |   9 +-
 tests/qemu-iotests/055         | 118 +++++++++++++++++++++++++
 tests/qemu-iotests/055.out     |   4 +-
 tests/qemu-iotests/iotests.py  |  10 +--
 19 files changed, 374 insertions(+), 425 deletions(-)

-- 
2.5.0