Re: [Qemu-devel] [2.3 PATCH v7 00/10] block: Incremental backup series

[John Snow <jsnow@redhat.com>]

On 11/25/2014 02:46 PM, John Snow wrote:
> This is the in memory part of the incremental backup feature.
>
> With the added commands, we can create a bitmap on a block backend, from which
> point of time all the writes are tracked by the bitmap, marking sectors as
> dirty.  Later, we call drive-backup and pass the bitmap to it, to do an
> incremental backup.
>
> See the last patch which adds some tests for this use case.
>
> Fam
>
> ==
>
> This is the next iteration of Fam's incremenetal backup feature.
> I have since taken this over from him and have (slowly) worked through
> the feedback to the last version of his patch and have made many
> tiny little edits.
>
> -John.
>
> v7: (highlights)
>   - First version being authored by jsnow
>   - Addressed most list feedback from V6, many small changes.
>     All feedback was either addressed on-list (as a wontfix) or patched.
>   - Replaced all error_set with error_setg
>   - Replaced all bdrv_find with bdrv_lookup_bs()
>   - Adjusted the max granularity to share a common function with
>     backup/mirror that attempts to "guess" a reasonable default.
>     It clamps between [4K,64K] currently.
>   - The BdrvDirtyBitmap object now counts granularity exclusively in
>     bytes to match its interface.
>     It leaves the sector granularity concerns to HBitmap.
>   - Reworked the backup loop to utilize the hbitmap iterator.
>     There are some extra concerns to handle arrhythmic cases where the
>     granularity of the bitmap does not match the backup cluster size.
>     This iteration works best when it does match, but it's not a
>     deal-breaker if it doesn't -- it just gets less efficient.
>   - Reworked the transactional functions so that abort() wouldn't "undo"
>     a redundant command. They now have been split into a prepare and a
>     commit function (with state) and do not provide an abort command.
>   - Added a block_dirty_bitmap_lookup(device, name, errp) function to
>     shorten a few of the commands added in this series, particularly
>     qmp_enable, qmp_disable, and the transaction preparations.
>
> v6: Re-send of v5.
>
> v5: Rebase to master.
>
> v4: Last version tailored by Fam Zheng.
>
> Fam Zheng (10):
>    qapi: Add optional field "name" to block dirty bitmap
>    qmp: Add block-dirty-bitmap-add and block-dirty-bitmap-remove
>    block: Introduce bdrv_dirty_bitmap_granularity()
>    hbitmap: Add hbitmap_copy
>    block: Add bdrv_copy_dirty_bitmap and bdrv_reset_dirty_bitmap
>    qmp: Add block-dirty-bitmap-enable and block-dirty-bitmap-disable
>    qmp: Add support of "dirty-bitmap" sync mode for drive-backup
>    qapi: Add transaction support to block-dirty-bitmap-{add, enable,
>      disable}
>    qmp: Add dirty bitmap 'enabled' field in query-block
>    qemu-iotests: Add tests for drive-backup sync=dirty-bitmap
>
>   block-migration.c             |   2 +-
>   block.c                       | 114 +++++++++++++++++++--
>   block/backup.c                | 128 ++++++++++++++++++++----
>   block/mirror.c                |  16 ++-
>   blockdev.c                    | 226 +++++++++++++++++++++++++++++++++++++++++-
>   hmp.c                         |   4 +-
>   include/block/block.h         |  17 +++-
>   include/block/block_int.h     |   6 ++
>   include/qemu/hbitmap.h        |   8 ++
>   qapi-schema.json              |   5 +-
>   qapi/block-core.json          | 123 ++++++++++++++++++++++-
>   qmp-commands.hx               |  66 +++++++++++-
>   tests/qemu-iotests/056        |  33 +++++-
>   tests/qemu-iotests/056.out    |   4 +-
>   tests/qemu-iotests/iotests.py |   8 ++
>   util/hbitmap.c                |  16 +++
>   16 files changed, 722 insertions(+), 54 deletions(-)
>

Script missed the CCs. Sigh.

For convenience:
Github: https://github.com/jnsnow/qemu/tree/dbm-backup
Git: https://github.com/jnsnow/qemu.git

Thanks,
--js