Re: [Qemu-devel] [RFC 2/6] block: add bdrv_set_copy_on_read()

[Stefan Hajnoczi]

On Wed, Nov 2, 2011 at 4:36 PM, Kevin Wolf <address@hidden> wrote:
> Am 17.10.2011 17:47, schrieb Stefan Hajnoczi:
>> The bdrv_set_copy_on_read() function can be used to programmatically
>> enable or disable copy-on-read for a block device.  Later patches add
>> the actual copy-on-read logic.
>>
>> Signed-off-by: Stefan Hajnoczi <address@hidden>
>> ---
>>  block.c     |   17 +++++++++++++++++
>>  block.h     |    3 +++
>>  block_int.h |    1 +
>>  3 files changed, 21 insertions(+), 0 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index 2d2c62a..e624ac3 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -464,6 +464,18 @@ int bdrv_parse_cache_flags(const char *mode, int *flags)
>>      return 0;
>>  }
>>
>> +void bdrv_set_copy_on_read(BlockDriverState *bs, int enable)
>
> bool enable

Thanks for pointing this out.

>> +{
>> +    if (bs->copy_on_read != enable) {
>> +        if (enable) {
>> +            bdrv_start_request_tracking(bs);
>> +        } else {
>> +            bdrv_stop_request_tracking(bs);
>> +        }
>> +    }
>> +    bs->copy_on_read = enable;
>> +}
>> +
>>  /*
>>   * Common part for opening disk images and files
>>   */
>> @@ -483,6 +495,11 @@ static int bdrv_open_common(BlockDriverState *bs, const 
>> char *filename,
>>      bs->open_flags = flags;
>>      bs->buffer_alignment = 512;
>>
>> +    bs->copy_on_read = 0;
>
> I think it should rather be reset on close. We can assert() it here.

Okay.

Stefan