[Gluster-devel] how to distinguish whether the current xlator is used in the client or the server?

[Mingfan Lu]

1. use option is a good idea
2. we could also traverse the this->children to see whether there is a
xlator with type == protocol/client  (depth first!)
   and save cache value in conf->use_with_client
gf_boolean_t
could_use_xlator(xlator_t *this)
{
      struct ios_conf  *conf = NULL;
      gf_boolean_t ret_value = _gf_false;
      conf = this->private;

      if(!conf) {
              gf_log(this->name, GF_LOG_INFO, "configuration should not be
null when check whether on client xlator");
              return ret_value;
      }

      LOCK(&conf->lock);
      {
              if (conf->check_use_client == _gf_true) {
                      gf_log(this->name, GF_LOG_INFO, "use the cached
value");
                      ret_value = conf->use_with_client;
              } else {
                      conf->use_with_client = ret_value =
trav_children(this);
                      conf->check_use_client = _gf_true;
              }
      }
      UNLOCK(&conf->lock);
      return ret_value;
}

gf_boolean_t
trav_children(xlator_t *this)
{
   xlator_list_t * children = this->children;
   while(children)
   {
      gf_log(this->name, GF_LOG_INFO, "children - name %s type %s ",
children->xlator->name, children->xlator->type);
      if (children->xlator->init_succeeded &&
strcmp(children->xlator->type, "protocol/client") == 0) {
          return _gf_true;
      }
      if(trav_children(children -> xlator) == _gf_true) {
          return _gf_true;
      }
      children = children->next;
   }
   return _gf_false;
}


and then,



On Tue, Dec 17, 2013 at 2:31 AM, Vijay Bellur <vbellur at redhat.com> wrote:

> On 12/16/2013 04:20 PM, Pranith Kumar Karampuri wrote:
>
>> hi Mingfan Lu,
>>      xlators are not supposed to know which part of the stack they belong
>> to. If you think the functionality needs to be different when it is in
>>  server vs client side. Would writing two different xlators one for
>> client side and the other for server side make sense?
>>
>
> You can also consider having optional behavior and enable the appropriate
> option in the client/server volume files for the xlator to behave
> differently. For e.g. the compression translator is loaded in both client
> and server stacks, but it performs compression/de-compression for the
> appropriate fops by looking at option 'mode'.
>
> -Vijay
>
>
>
>> Pranith.
>> ----- Original Message -----
>>
>>> From: "Mingfan Lu" <mingfan.lu at gmail.com>
>>> To: gluster-devel at nongnu.org
>>> Sent: Monday, December 16, 2013 2:55:24 PM
>>> Subject: [Gluster-devel] how to distinguish whether the current xlator
>>> is used in the client or the server?
>>>
>>> When I write a xlator for glusterfs, the xlator could be used for client
>>> and
>>> server. but when being used in server and client, the behavior of the
>>> xlator
>>> could be some-what differrent. How could I know whether the xlator is
>>> used
>>> in glusterfs or glusterfsd when I developing the xlator? then I could
>>> tune
>>> the code path for client and server.
>>>
>>> _______________________________________________
>>> Gluster-devel mailing list
>>> Gluster-devel at nongnu.org
>>> https://lists.nongnu.org/mailman/listinfo/gluster-devel
>>>
>>>
>> _______________________________________________
>> Gluster-devel mailing list
>> Gluster-devel at nongnu.org
>> https://lists.nongnu.org/mailman/listinfo/gluster-devel
>>
>>
>>
>
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