Re: [Qemu-devel] [PATCH 2/5] block/qcow2-bitmap: Allow bitmap flushing

[Eric Blake]

On 3/5/19 5:43 PM, John Snow wrote:
> Usually, we only write out bitmaps when we're about to close out the file,
> so we always remove the bitmaps after to make it easier to determine the
> source of truth for migration purposes.
> 
> However, there may be times we want to flush bitmap data more aggressively,
> like after a truncate event where we need to make the metadata consistent
> again.

Or, as I've mentioned in other threads, after every
bitmap-add/bitmap-delete operation, so that 'qemu-img info -U' can see
which persistent bitmaps exist. But that's one step further than this
series, so I won't insist on it today.

> 
> Signed-off-by: John Snow <address@hidden>
> ---
>  block/qcow2.h        |  1 +
>  block/qcow2-bitmap.c | 45 ++++++++++++++++++++++++++++++--------------
>  2 files changed, 32 insertions(+), 14 deletions(-)
> 

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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