[pve-devel] [HACK qemu 06/13] block/{copy-before-write, snapshot-access}: implement bdrv_co_get_info driver callback

[Fiona Ebner]

Am 25.01.24 um 15:41 schrieb Fiona Ebner:
> In preparation to fix an issue for backup fleecing where discarding
> the source would lead to an assertion failure when the fleecing image
> has larger granularity than the backup target.
> 
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
> 
> Still need to wait on a response from upstream. For now this hack, so
> that the RFC as a whole doesn't have to wait.
> 

>From [0]:

> 2. if we need another logic for block_copy_calculate_cluster_size() it should be an option. May be 
> explicit "copy-cluster-size" or "granularity" option for CBW driver and for backup 
> job. And we'll just check that given cluster-size is power of two >= target_size.

I implemented a new option based on this suggestion and it also resolves
the issue. So the hacks will be gone in the next version :) Will also
try to upstream the option after v3 of the patch series from [0] is out.

[0]: https://lists.nongnu.org/archive/html/qemu-devel/2024-01/msg05131.html