Re: [Qemu-devel] [PATCH 0/8] block: persistent dirty bitmaps (RFC)

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

On 13.01.2015 20:02, Vladimir Sementsov-Ogievskiy wrote:
> The bitmaps are saved into qcow2 file format. It provides both
> 'internal' and 'external' dirty bitmaps feature:
>   - for qcow2 drives we can store bitmaps in the same file
>   - for other formats we can store bitmaps in the separate qcow2 file
>
> QCow2 header is extended by fields 'nb_dirty_bitmaps' and
> 'dirty_bitmaps_offset' like with snapshots.
>
> Proposed command line syntax is the following:
>
> -dirty-bitmap [option1=val1][,option2=val2]...
>      Available options are:
>      name         The name for the bitmap (necessary).
>
>      file         The file to load the bitmap from.
>
>      file_id      When specified with 'file' option, then this file will
>                   be available through this id for other -dirty-bitmap
>                   options when specified without 'file' option, then it
>                   is a reference to 'file', specified with another
>                   -dirty-bitmap option, and it will be used to load the
>                   bitmap from.
>
>      drive        The drive to bind the bitmap to. It should be specified
>                   as 'id' suboption of one of -drive options. If nor
>                   'file' neither 'file_id' are specified, then the bitmap
>                   will be loaded from that drive (internal dirty bitmap).
>
>      granularity  The granularity for the bitmap. Not necessary, the
>                   default value may be used.
>
>      enabled      on|off. Default is 'on'. Disabled bitmaps are not
>                   changing regardless of writes to corresponding drive.
>
> Examples:
>
> qemu -drive file=a.qcow2,id=disk -dirty-bitmap name=b,drive=disk
> qemu -drive file=a.raw,id=disk \
>       -dirty-bitmap name=b,drive=disk,file=b.qcow2,enabled=off
>
> Vladimir Sementsov-Ogievskiy (8):
>    spec: add qcow2-dirty-bitmaps specification
>    hbitmap: store / restore
>    qcow2: add dirty-bitmaps feature
>    block: store persistent dirty bitmaps
>    block: add bdrv_load_dirty_bitmap
>    qemu: command line option for dirty bitmaps
>    qmp: print dirty bitmap
>    iotests: test internal persistent dirty bitmap
>
>   block.c                    | 113 ++++++++++
>   block/Makefile.objs        |   2 +-
>   block/qcow2-dirty-bitmap.c | 514 +++++++++++++++++++++++++++++++++++++++++++++
>   block/qcow2.c              |  26 +++
>   block/qcow2.h              |  48 +++++
>   blockdev.c                 |  51 +++++
>   docs/specs/qcow2.txt       |  59 ++++++
>   hmp-commands.hx            |  15 ++
>   hmp.c                      |   8 +
>   hmp.h                      |   1 +
>   include/block/block.h      |   9 +
>   include/block/block_int.h  |  10 +
>   include/qemu/hbitmap.h     |  49 +++++
>   include/sysemu/blockdev.h  |   1 +
>   include/sysemu/sysemu.h    |   1 +
>   qapi-schema.json           |   3 +-
>   qapi/block-core.json       |   3 +
>   qemu-options.hx            |  37 ++++
>   qmp-commands.hx            |   5 +
>   tests/qemu-iotests/115     |  96 +++++++++
>   tests/qemu-iotests/115.out |  64 ++++++
>   tests/qemu-iotests/group   |   1 +
>   util/hbitmap.c             |  87 ++++++++
>   vl.c                       | 100 +++++++++
>   24 files changed, 1301 insertions(+), 2 deletions(-)
>   create mode 100644 block/qcow2-dirty-bitmap.c
>   create mode 100755 tests/qemu-iotests/115
>   create mode 100644 tests/qemu-iotests/115.out
>

Ping. I've already done (locally):
1) using qcow2 header extension instead of changing the header
2) normal qmp query request instead of "print dirty bitmap"
  - thanks to Eric and Markus

Now I'm waiting for some comments on the concept and it's realization to 
roll v3.

-- 
Best regards,
Vladimir