Re: [PATCH v3 6/6] block/qcow2: use seqcache for compressed writes

[Vladimir Sementsov-Ogievskiy]

12.03.2021 21:15, Max Reitz wrote:
> > @@ -1834,6 +1835,10 @@ static int coroutine_fn qcow2_do_open(BlockDriverState 
> > *bs, QDict *options,
> >       s->inflight_writes_counters =
> >           g_hash_table_new_full(g_int64_hash, g_int64_equal, g_free, g_free);
> > +    if (!has_data_file(bs) && (bs->file->bs->open_flags & BDRV_O_NOCACHE)) {
>
> Looks a bit like a layering violation, but I have no better proposal and you 
> gave your reasoning, so, OK.

Probably better is check request_alignment of bs->file->bs. If it > 1 then 
enable the cache.

--
Best regards,
Vladimir