Re: [Qemu-devel] [PULL 30/42] block: define get_block_status return value

[Paolo Bonzini <pbonzini@redhat.com>]

Il 13/09/2013 10:04, Peter Lieven ha scritto:
> On 06.09.2013 17:39, Stefan Hajnoczi wrote:
>> From: Paolo Bonzini <pbonzini@redhat.com>
>>
>> Define the return value of get_block_status.  Bits 0, 1, 2 and 9-62
>> are valid; bit 63 (the sign bit) is reserved for errors.  Bits 3-8
>> are left for future extensions.
>>
>> The return code is compatible with the old is_allocated API: if a driver
>> only returns 0 or 1 (aka BDRV_BLOCK_DATA) like is_allocated used to,
>> clients of is_allocated will not have any change in behavior.  Still,
>> we will return more precise information in the next patches and the
>> new definition of bdrv_is_allocated is already prepared for this.
>>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>> ---
>>   block.c               | 10 ++++++++--
>>   include/block/block.h | 26 ++++++++++++++++++++++++++
>>   2 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index a5bfe74..97406ec 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -3093,7 +3093,7 @@ static int64_t coroutine_fn
>> bdrv_co_get_block_status(BlockDriverState *bs,
>>         if (!bs->drv->bdrv_co_get_block_status) {
>>           *pnum = nb_sectors;
>> -        return 1;
>> +        return BDRV_BLOCK_DATA;
>>       }
>>         return bs->drv->bdrv_co_get_block_status(bs, sector_num,
>> nb_sectors, pnum);
>> @@ -3143,7 +3143,13 @@ int64_t bdrv_get_block_status(BlockDriverState
>> *bs, int64_t sector_num,
>>   int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t
>> sector_num,
>>                                      int nb_sectors, int *pnum)
>>   {
>> -    return bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
>> +    int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors,
>> pnum);
>> +    if (ret < 0) {
> sorry if I repeat myself.
> 
> isn't here a *pnum = 0 missing?

I think an earlier patch makes it unnecessary, because I'm checking the
return status of bdrv_get_block_status and bdrv_is_allocated.  In any
case the right place to put it would be in bdrv_get_block_status.

Paolo