Re: [Qemu-devel] [PATCH 2/3] qcow2: Always execute preallocate() in a coroutine

[Max Reitz]

On 2017-10-10 00:28, Eric Blake wrote:
> On 10/09/2017 04:55 PM, Max Reitz wrote:
>> Some qcow2 functions (at least perform_cow()) expect s->lock to be
>> taken.  Therefore, if we want to make use of them, we should execute
>> preallocate() (as "preallocate_co") in a coroutine so that we can use
>> the qemu_co_mutex_* functions.
>>
>> Signed-off-by: Max Reitz <address@hidden>
>> ---
>>  block/qcow2.c | 41 ++++++++++++++++++++++++++++++++++-------
>>  1 file changed, 34 insertions(+), 7 deletions(-)
>>
> 
>> +++ b/block/qcow2.c
>> @@ -2460,6 +2460,14 @@ static int qcow2_set_up_encryption(BlockDriverState 
>> *bs, const char *encryptfmt,
>>  }
>>  
>>  
>> +typedef struct PreallocCo {
>> +    BlockDriverState *bs;
>> +    uint64_t offset;
>> +    uint64_t new_length;
>> +
>> +    int ret;
>> +} PreallocCo;
> 
> Because you create a typedef here...
> 
> 
>> +static void coroutine_fn preallocate_co(void *opaque)
>>  {
>> +    struct PreallocCo *params = opaque;
> 
> you could drop 'struct' here, the way you already dropped it...

Ah, yes, that was from before I added the typedef...  Will fix.

Max

> 
>> +static int preallocate(BlockDriverState *bs,
>> +                       uint64_t offset, uint64_t new_length)
>> +{
>> +    PreallocCo params = {
>> +        .bs         = bs,
>> +        .offset     = offset,
>> +        .new_length = new_length,
>> +        .ret        = -EINPROGRESS,
>> +    };
> 
> ...here.  But that doesn't change semantics, so either way,
> 
> Reviewed-by: Eric Blake <address@hidden>
>

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