Re: [Qemu-devel] [PATCH v17 18/23] block: Reuse bs as backing hd for drive-backup sync=none

[Fam Zheng]

On Wed, 05/03 00:35, Fam Zheng wrote:
> Opening the backing image for the second time is bad, especially here
> when it is also in use as the active image as the source. The
> drive-backup job itself doesn't read from target->backing for COW,
> instead it gets data from the write notifier, so it's not a big problem.
> However, exporting the target to NBD etc. won't work, because of the
> likely stale metadata cache.
> 
> Use BDRV_O_NO_BACKING in this case and manually set up the backing
> BdrvChild.
> 
> Cc: address@hidden
> Signed-off-by: Fam Zheng <address@hidden>

Actually Cc qemu-stable. (git-publish does unified Cc for each patch in a whole
series, hence the noise. Sorry.)

Fam