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 from 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 from v5:
- rebased on master
- fix grammar (5, 8)
Changes from v6:
- more grammar fixes (1,11)
- assignment cleanup as suggested by Eric in 11
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 | 24 ++---
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, 366 insertions(+), 425 deletions(-)
--
2.1.4