From: Kevin Wolf <kwolf@redhat.com>
To: Eric Blake <eblake@redhat.com>
Cc: vsementsov@virtuozzo.com, qemu-block@nongnu.org,
armbru@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com,
pkrempa@redhat.com, jsnow@redhat.com
Subject: Re: [PATCH v3 0/6] block: add block-dirty-bitmap-populate job
Date: Tue, 23 Jun 2020 13:47:14 +0200 [thread overview]
Message-ID: <20200623114714.GH5853@linux.fritz.box> (raw)
In-Reply-To: <20200619195621.58740-1-eblake@redhat.com>
Am 19.06.2020 um 21:56 hat Eric Blake geschrieben:
> [From John's original cover letter:]
> This is a new (very small) block job that writes a pattern into a
> bitmap. The only pattern implemented is the top allocation information.
>
> This can be used to "recover" an incremental bitmap chain if an external
> snapshot was taken without creating a new bitmap first: any writes made
> to the image will be reflected by the allocation status and can be
> written back into a bitmap.
>
> This is useful for e.g. libvirt managing backup chains if a user creates
> an external snapshot outside of libvirt.
>
> v3:
> - Addressed a bit more feedback
> - Make it easier to decide if we want an x- prefix if we think there
> are more tweaks to be made to the interface
> - Drop dependency on John's JobRunner iotest series
> - Renumber the new iotest
>
> I know there was a lot of discussion about whether there are
> optimizations to be made with populating directly into the target
> bitmap rather than into a temporary that then gets merged in at the
> completion of the job, but the QMP aspect seems fairly stable. Even
> so, we may still want to consider using an x- prefix until we know for
> sure whether libvirt can make decent use of the interface.
Fair enough, as long as everyone agrees that the QMP aspect includes
that merging the bits only at the end of the job is an implementation
detail and not something that client may rely on.
Kevin
prev parent reply other threads:[~2020-06-23 12:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 19:56 [PATCH v3 0/6] block: add block-dirty-bitmap-populate job Eric Blake
2020-06-19 19:56 ` [PATCH v3 1/6] block: add bitmap-populate job Eric Blake
2020-06-20 4:16 ` Vladimir Sementsov-Ogievskiy
2020-06-22 21:44 ` Eric Blake
2020-06-23 7:01 ` Vladimir Sementsov-Ogievskiy
2020-09-02 15:58 ` Eric Blake
2020-06-23 11:50 ` Kevin Wolf
2020-06-19 19:56 ` [PATCH v3 2/6] blockdev: combine DriveBackupState and BlockdevBackupState Eric Blake
2020-06-22 5:12 ` Vladimir Sementsov-Ogievskiy
2020-06-22 21:45 ` Eric Blake
2020-06-19 19:56 ` [PATCH v3 3/6] qmp: expose block-dirty-bitmap-populate Eric Blake
2020-06-19 19:56 ` [PATCH v3 4/6] iotests: move bitmap helpers into their own file Eric Blake
2020-06-22 5:26 ` Vladimir Sementsov-Ogievskiy
2020-06-19 19:56 ` [PATCH v3 5/6] iotests: add 298 for block-dirty-bitmap-populate Eric Blake
2020-06-19 19:56 ` [PATCH v3 6/6] bitmaps: Use x- prefix for block-dirty-bitmap-popluate Eric Blake
2020-06-23 11:45 ` Kevin Wolf
2020-06-23 11:47 ` Kevin Wolf [this message]
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