Re: [Qemu-block] [PATCH v2 12/17] block: Convert bdrv_write() to BdrvChild

[Max Reitz]

On 29.06.2016 17:33, Kevin Wolf wrote:
> Am 29.06.2016 um 17:22 hat Max Reitz geschrieben:
>> On 29.06.2016 14:11, Kevin Wolf wrote:
>>> Signed-off-by: Kevin Wolf <address@hidden>
>>> Acked-by: Stefan Hajnoczi <address@hidden>
>>> ---
>>>
>>> This patch contains non-trivial fixes, so I think it's worth sending out a 
>>> v2
>>> for it even though I already applied the series. I added a coroutine entry
>>> wrapper qcow(2)_write that can be used from .bdrv_write_compressed. These
>>> wrappers will soon disappear again when .bdrv_write_compressed is changed 
>>> into
>>> .bdrv_co_pwritev_compressed (Pavel Butsykin's backup compression series).
>>>
>>>  block/io.c             |  5 +++--
>>>  block/qcow.c           | 45 ++++++++++++++++++++++++++++++++++++++++++++-
>>>  block/qcow2-cluster.c  |  2 +-
>>>  block/qcow2-refcount.c |  2 +-
>>>  block/qcow2.c          | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
>>>  block/vdi.c            |  4 ++--
>>>  block/vvfat.c          |  5 ++---
>>>  include/block/block.h  |  2 +-
>>>  8 files changed, 100 insertions(+), 12 deletions(-)
>>
>> Reviewed-by: Max Reitz <address@hidden>
>>
>> [...]
>>
>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>> index 0178931..cd9c27b 100644
>>> --- a/block/qcow2.c
>>> +++ b/block/qcow2.c
>>> @@ -2533,6 +2533,51 @@ static int qcow2_truncate(BlockDriverState *bs, 
>>> int64_t offset)
>>>      return 0;
>>>  }
>>>  
>>> +typedef struct Qcow2WriteCo {
>>> +    BlockDriverState *bs;
>>> +    int64_t sector_num;
>>> +    const uint8_t *buf;
>>> +    int nb_sectors;
>>> +    int ret;
>>> +} Qcow2WriteCo;
>>> +
>>> +static void qcow2_write_co_entry(void *opaque)
>>> +{
>>> +    Qcow2WriteCo *co = opaque;
>>> +    QEMUIOVector qiov;
>>> +    uint64_t offset = co->sector_num * BDRV_SECTOR_SIZE;
>>> +    uint64_t bytes = co->nb_sectors * BDRV_SECTOR_SIZE;
>>
>> It doesn't make much sense to make this a uint64_t, and I'm afraid
>> Coverity will complain about it... It's not wrong, though, but an int
>> would have been more "honest".
> 
> Hm, just copied from vmdk... Anyway, you right that we don't really need
> uint64_t here because of BDRV_REQUEST_MAX_SECTORS, but BDRV_SECTOR_SIZE
> is unsigned long long, so at least this is a proper 64 bit calculation
> and Coverity should stay silent.

Oh, right, I missed that. That is actually very clever, I should
remember that.

Max

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