Re: [PATCH 3/3] nfsd41: implement NFS4_SHARE_WANT_NO_DELEG, NFS4_OPEN_DELEGATE_NONE_EXT, why_no_deleg

[Benny Halevy <bhalevy@tonian.com>]

On 2012-02-18 00:14, J. Bruce Fields wrote:
> On Thu, Feb 16, 2012 at 08:57:17PM +0200, Benny Halevy wrote:
>> Respect client request for not getting a delegation in NFSv4.1
>> Appropriately return delegation "type" NFS4_OPEN_DELEGATE_NONE_EXT
>> and WND4_NOT_WANTED reason.
> 
> These all look fine, just two nits:
> 
>> @@ -2903,11 +2903,32 @@ static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
>>  	dprintk("NFSD: delegation stateid=" STATEID_FMT "\n",
>>  		STATEID_VAL(&dp->dl_stid.sc_stateid));
>>  out:
>> -	if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS
>> -			&& flag == NFS4_OPEN_DELEGATE_NONE
>> -			&& open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
>> -		dprintk("NFSD: WARNING: refusing delegation reclaim\n");
>>  	open->op_delegate_type = flag;
>> +	if (flag == NFS4_OPEN_DELEGATE_NONE) {
>> +		if (open->op_claim_type == NFS4_OPEN_CLAIM_PREVIOUS &&
>> +		    open->op_delegate_type != NFS4_OPEN_DELEGATE_NONE)
>> +			dprintk("NFSD: WARNING: refusing delegation reclaim\n");
>> +
>> +		if (open->op_deleg_want) {
>> +			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
>> +			if (status == -EAGAIN)
>> +				open->op_why_no_deleg = WND4_CONTENTION;
>> +			else {
>> +				open->op_why_no_deleg = WND4_RESOURCE;
>> +				switch (open->op_deleg_want) {
>> +				case NFS4_SHARE_WANT_READ_DELEG:
>> +				case NFS4_SHARE_WANT_WRITE_DELEG:
>> +				case NFS4_SHARE_WANT_ANY_DELEG:
>> +					break;
>> +				case NFS4_SHARE_WANT_CANCEL:
>> +					open->op_why_no_deleg = WND4_CANCELLED;
>> +					break;
>> +				case NFS4_SHARE_WANT_NO_DELEG:
>> +					BUG();	/* not supposed to get here */
>> +				}
>> +			}
>> +		}
>> +	}
> 
> This looks like a reasonably well-encapsulated bit of code--could you
> move it into a helper function?
> 
>>  out:
>> +	/* 4.1 client trying to upgrade/downgrade delegation? */
>> +	if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&
>> +	    open->op_deleg_want) {
>> +		if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
>> +		    dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
>> +			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
>> +			open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
>> +		} else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
>> +			   dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
>> +			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
>> +			open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
>> +		}
>> +		/* Otherwise the client must be confused wanting a delegation
>> +		 * it already has, therefore we don't return
>> +		 * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
>> +		 */
>> +	}
> 
> Ditto for this.
> 
> I'll go ahead and apply the previous two patches pending some regression
> tests.

Thanks!
I'm sending two additional patches that refactor these two helpers and add
some documentation to the commit message.

I think it might be helpful to keep them separated but let me know otherwise
and I'll send a squashed patch instead.

Benny

> 
> --b.
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