Re: [Qemu-devel] [PATCH v2 3/6] block: require job-id when device is a node name

[Manos Pitsidianakis <el13635@mail.ntua.gr>]

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On Tue, Aug 22, 2017 at 11:57:28AM +0200, Alberto Garcia wrote:
>On Mon 21 Aug 2017 05:39:48 PM CEST, Manos Pitsidianakis wrote:
>>>> -    if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
>>>> -        job_id = bdrv_get_device_name(bs);
>>>> -        if (!*job_id) {
>>>> -            error_setg(errp, "An explicit job ID is required for this node");
>>>> -            return NULL;
>>>> -        }
>>>> -    }
>>>> -
>>>> -    if (job_id) {
>>>> -        if (flags & BLOCK_JOB_INTERNAL) {
>>>> +    if (flags & BLOCK_JOB_INTERNAL) {
>>>> +        if (job_id) {
>>>>              error_setg(errp, "Cannot specify job ID for internal block job");
>>>>              return NULL;
>>>>          }
>>>
>>>When BLOCK_JOB_INTERNAL is set, then job_id must be NULL...
>>>
>>>> -
>>>> +    } else {
>>>> +        /* Require job-id. */
>>>> +        assert(job_id);
>>>>          if (!id_wellformed(job_id)) {
>>>>              error_setg(errp, "Invalid job ID '%s'", job_id);
>>>>              return NULL;
>>>> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
>>>> index f13ad05c0d..ff906808a6 100644
>>>> --- a/include/block/blockjob_int.h
>>>> +++ b/include/block/blockjob_int.h
>>>> @@ -112,8 +112,7 @@ struct BlockJobDriver {
>>>>
>>>>  /**
>>>>   * block_job_create:
>>>> - * @job_id: The id of the newly-created job, or %NULL to have one
>>>> - * generated automatically.
>>>> + * @job_id: The id of the newly-created job, must be non %NULL.
>>>
>>>...but here you say that it must not be NULL.
>>>
>>>And since job_id can be NULL in some cases I think I'd replace the
>>>assert(job_id) that you added to block_job_create() with a normal
>>>pointer check + error_setg().
>>>
>>>> @@ -93,9 +93,6 @@ static void test_job_ids(void)
>>>>      blk[1] = create_blk("drive1");
>>>>      blk[2] = create_blk("drive2");
>>>>
>>>> -    /* No job ID provided and the block backend has no name */
>>>> -    job[0] = do_test_id(blk[0], NULL, false);
>>>> -
>>>
>>>If you decide to handle NULL ids by returning and error instead of
>>>asserting, we should keep a couple of tests for that scenario.
>>>
>>>Berto
>>>
>>
>> Thanks, I will change that. What cases are you thinking of besides
>> internal jobs though?
>
>Both cases (external job with a NULL id and internal job with non-NULL
>id), checking that block_job_create() does return an error.

I thought we handled the external job case by requiring job_id is set 
before calling block_job_create(). I will check my patch again.

>
>> And should documentation of block_job_create reflect that internal
>> jobs have job_id == NULL?
>
>Yes, it should document the restrictions of the job_id parameter.
>
>Berto
>

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