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

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

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

-- 
1.9.1