[Qemu-devel] Re: [PATCH 1/4] block: clarify the meaning of BDRV_O_NOCACHE

[Stefan Hajnoczi]

On Wed, Mar 16, 2011 at 2:08 PM, Christoph Hellwig <address@hidden> wrote:
> On Wed, Mar 16, 2011 at 09:42:37AM +0000, Stefan Hajnoczi wrote:
>> -    writethrough = ((flags & BDRV_O_CACHE_MASK) == 0);
>> +    writethrough = ((flags & (BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)) == 0);
>
> or rather
>
>        writethrough = ((flags & (BDRV_O_CACHE_WB) != );
>
> but yes, this code had sneaked in since my initial version.

My intention was that if we don't care about honoring flushes then we
might as well use Qcow2Cache.  But yes, just checking for cache mode
is the clearest.

Stefan