[Freeipa-devel] [PATCH 0014] correct handling of one directional segments

[Ludwig Krispenz]

On 06/17/2015 10:35 AM, thierry bordaz wrote:
> On 06/17/2015 09:25 AM, Ludwig Krispenz wrote:
>> Hi,
>> thanks for review, see answers inline.
>>
>> On 06/16/2015 05:17 PM, thierry bordaz wrote:
>>> On 06/16/2015 11:41 AM, Ludwig Krispenz wrote:
>>>> this patch adresses issues in checking existing segments for one 
>>>> directional segments and correctly handles the merging of segments, 
>>>> so that all agreements will be removed when the merged segment is 
>>>> deleted
>>>>
>>>>
>>>
>>> This is looking good to me with few comments
>>>
>>>   * in ipa_topo_cfg_replica_segment_find, if 'dir=0' or
>>>     'dir=bidirectionnal' the reverse direction is bidirectionnal. Is
>>>     it the expected result ?
>>>
>> yes. 0 does not exist as valid direct and if we are looking for 
>> (A,B,both) this could als be expressed as (B,A,both). we do not 
>> really look for a opposite direction of (A,B,dir) but for a segment 
>> (B,A,revdir) which covers this segment.
>>>
>>>   *  in ipa_topo_check_segment_is_valid and
>>>     ipa_topo_util_find_segment, may be hardening
>>>     leftnode,rightnode,dir if they are NULL. (if the entry violate
>>>     schema).
>>>
>> if we can arrive at a state where an entry violates the schema I 
>> think we have more trouble, I want to avoid adding code for handling 
>> errors which cannot exist.
>
> Hi Ludwig,
>
> thanks for your explanations. All of them makes sense and so for me 
> the patch is valid.
>
> I have a minor question about schema violation. When we add an entry, 
> in preop we did not yet check the schema.
> So ipa_topo_pre_add->ipa_topo_check_segment_is_valid may be called 
> with an invalid segment entry where some attributes are missing (like 
> ipaReplTopoSegmentDirection).
good point, in preop we cannot rely on schema been checked, need to add 
a check.
>
> Also something that is not clear to.
> I have a segment seg=ipa_topo_cfg_replica_segment_find(.., A, B, 
> SEGMENT_RIGHT_LEFT, ..);. my understanding is that seg->right != 0 and 
> seg->left == 0. is that correct ?
no :-) one directional segments are a bit confusing.  a replication 
agreement B-->A can be represented by a segment (A,B,right-left) or 
(B,A,left-right). when doing segment_find (A,B,right-left) we are 
looking if any segment covers this and teh result could be a segment
(B,A,left right with seg->left !=0
>
> thanks
> thierry
>>>
>>>   * ipa_topo_util_segm_dir if direction does not match any of the
>>>     strings, it returns -1. 0 would be better if we decide to test
>>>     bit mask.
>>>
>> yes, but in preop we check that only valid directions are added, so 
>> it might be unnecesarry to handle it, but if you want I can change it.
>>>
>>>   * in ipa_topo_util_segment_update:810, ex_segm is a rigth_left
>>>     segment. Why trying to call ipa_topo_cfg_agmt_dup with
>>>     ex_segm->left in priority. Why not ex_segm->right first ?
>>>
>> no, we don't know if it is a right-left segment. we have 
>> (A,B,left-right), the segment for the other direction could be 
>> (A.B,right-left) or (B,A,left-right). All we know is that it is not 
>> bidirectional, otherwise (A,B,left-right) would have been rejected in 
>> the preop test. So there is one agmt, left or right and take the 
>> existing one.
>>>
>>>  *
>>>
>>>
>>>   * in ipa_topo_util_delete_segments_for_host, If segment
>>>     localhost->delhost is bidirectional, how can it exists a reverse
>>>     segment delhost->localhost ? I thought those segments have been
>>>     merged ?
>>>
>> if it is bidirectional check_reverse is set to 0 and reveres is not 
>> attempted
>>>
>>>
>>> Thanks
>>> thierry
>>
>

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