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

["J. Bruce Fields" <bfields@fieldses.org>]

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.

--b.