Re: [Qemu-devel] [PATCH v6 11/42] block: Add bdrv_supports_compressed_writes()

[Kevin Wolf]

Am 09.08.2019 um 18:13 hat Max Reitz geschrieben:
> Filters cannot compress data themselves but they have to implement
> .bdrv_co_pwritev_compressed() still (or they cannot forward compressed
> writes).  Therefore, checking whether
> bs->drv->bdrv_co_pwritev_compressed is non-NULL is not sufficient to
> know whether the node can actually handle compressed writes.  This
> function looks down the filter chain to see whether there is a
> non-filter that can actually convert the compressed writes into
> compressed data (and thus normal writes).
> 
> Signed-off-by: Max Reitz <address@hidden>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>

Should patches 2 and 3 that add the .bdrv_co_pwritev_compressed()
callback to filter drivers come only after this one? And should we also
support it in the mirror filter?

Kevin