Re: [Qemu-devel] [PATCH 1.2 3/7] block: always open protocol in writeback mode

[Kevin Wolf]

Am 31.05.2012 13:43, schrieb Paolo Bonzini:
> Il 31/05/2012 13:33, Kevin Wolf ha scritto:
>>>> diff --git a/block.c b/block.c
>>>> index 7add33c..43b3de6 100644
>>>> --- a/block.c
>>>> +++ b/block.c
>>>> @@ -661,7 +661,7 @@ static int bdrv_open_common(BlockDriverState *bs, 
>>>> const char *filename,
>>>>      if (drv->bdrv_file_open) {
>>>>          ret = drv->bdrv_file_open(bs, filename, open_flags);
>> Why don't you add the writeback flag here? Would the code is raw-posix
>> that adds O_DSYNC be unused then. and can it still be used in other ways
>> than format=file/host_* with this patch?
> 
> Because in this case there is no format over it, so the topmost BDS will
> be open with BDRV_O_CACHE_WB and no one will call bdrv_flush.

Doesn't block.c do it now? bs->enable_write_cache still wouldn't be set,
even if .bdrv_file_open() is called with BDRV_O_CACHE_WB.

Kevin