Re: [PATCH 1/2] rbd: zero return code in rbd_dev_image_id()

[Dan Mick <dan.mick@inktank.com>]

OK, assuming the comment is changed to reflect the "we expect a data 
length back here" indication, Alex explained this offline and I agree.


On 10/22/2012 10:18 AM, Dan Mick wrote:
> I really feel like we ought to root-cause this before we patch the
> kernel client.  Something isn't working the way we expect.
>
> On 10/22/2012 09:44 AM, Alex Elder wrote:
>> There is a call in rbd_dev_image_id() to rbd_req_sync_exec()
>> to get the image id for an image.  Despite the "get_id" class
>> method only returning 0 on success, I am getting back a positive
>> value (I think the number of bytes returned with the call).
>>
>> That may or may not be how rbd_req_sync_exec() is supposed to
>> behave, but zeroing the return value if successful makes it moot
>> and makes this path through the code work as desired.
>>
>> Do the same in rbd_dev_v2_object_prefix().
>>
>> Signed-off-by: Alex Elder <elder@inktank.com>
>> ---
>>   drivers/block/rbd.c |    2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
>> index cf5d109..65e9f1f 100644
>> --- a/drivers/block/rbd.c
>> +++ b/drivers/block/rbd.c
>> @@ -2169,6 +2169,7 @@ static int rbd_dev_v2_object_prefix(struct
>> rbd_device *rbd_dev)
>>       dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret);
>>       if (ret < 0)
>>           goto out;
>> +    ret = 0;    /* rbd_req_sync_exec() can return positive */
>>
>>       p = reply_buf;
>>       rbd_dev->header.object_prefix = ceph_extract_encoded_string(&p,
>> @@ -2862,6 +2863,7 @@ static int rbd_dev_image_id(struct rbd_device
>> *rbd_dev)
>>       dout("%s: rbd_req_sync_exec returned %d\n", __func__, ret);
>>       if (ret < 0)
>>           goto out;
>> +    ret = 0;    /* rbd_req_sync_exec() can return positive */
>>
>>       p = response;
>>       rbd_dev->image_id = ceph_extract_encoded_string(&p,
>>