[Lustre-devel] Queries regarding LDLM_ENQUEUE

[Fan Yong]

  On 10/19/10 7:33 AM, Vilobh Meshram wrote:
> Hi,
>
> Out of the many RPC's used in Lustre seems like LDLM_ENQUEUE is the 
> most frequently used RPC to communicate between the client and the 
> MDS.I have few queries regarding the same :-
>
> 1) Is LDLM_ENQUEUE the only interface(RPC here) for CREATE/OPEN kind 
> of request ; through which the client can interact with the MDS ?
>
> I tried couple of experiments and found out that LDLM_ENQUEUE comes 
> into picture while mounting the FS as well as when we do a 
> lookup,create or open a file.I was expecting the MDS_REINT RPC to get 
> invoked in case of a CREATE/OPEN request via mdc_create() but it seems 
> like Lustre invokes LDLM_ENQEUE even for CREATE/OPEN( by packing the 
> intent related data).
> Please correct me if I am wrong.
For OPEN_CREATE case, it is through LDLM_ENQUEUE interface to 
communicate with MDS.
>
> 2) In which cases (which system calls) does the MDS_REINT RPC will get 
> invoked ?
You can try mkdir/symlink/mknode to trigger MDS_REINT.


Cheers,
--
Nasf
>
>
> Thanks,
> Vilobh
> /Graduate Research Associate
> Department of Computer Science
> The Ohio State University Columbus Ohio/
>
>
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