Re: [RFC v3 03/42] NFS CB_OFFLOAD xdr

[Anna Schumaker <schumaker.anna@gmail.com>]

Hi Olga,

On 07/11/2017 12:43 PM, Olga Kornievskaia wrote:
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
>  fs/nfs/callback.h      | 13 ++++++++
>  fs/nfs/callback_proc.c |  7 +++++
>  fs/nfs/callback_xdr.c  | 80 +++++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 99 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
> index c701c30..e4ab65d 100644
> --- a/fs/nfs/callback.h
> +++ b/fs/nfs/callback.h
> @@ -189,6 +189,19 @@ extern __be32 nfs4_callback_notify_lock(struct cb_notify_lock_args *args,
>  					 void *dummy,
>  					 struct cb_process_state *cps);
>  #endif /* CONFIG_NFS_V4_1 */
> +#ifdef CONFIG_NFS_V4_2
> +struct cb_offloadargs {
> +	struct nfs_fh		coa_fh;
> +	nfs4_stateid		coa_stateid;
> +	uint32_t		error;
> +	uint64_t		wr_count;
> +	struct nfs_writeverf	wr_writeverf;
> +};
> +
> +extern __be32 nfs4_callback_offload(
> +	struct cb_offloadargs *args,
> +	void *dummy, struct cb_process_state *cps);
> +#endif /* CONFIG_NFS_V4_2 */
>  extern int check_gss_callback_principal(struct nfs_client *, struct svc_rqst *);
>  extern __be32 nfs4_callback_getattr(struct cb_getattrargs *args,
>  				    struct cb_getattrres *res,
> diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
> index 52479f1..5396751 100644
> --- a/fs/nfs/callback_proc.c
> +++ b/fs/nfs/callback_proc.c
> @@ -647,3 +647,10 @@ __be32 nfs4_callback_notify_lock(struct cb_notify_lock_args *args, void *dummy,
>  	return htonl(NFS4_OK);
>  }
>  #endif /* CONFIG_NFS_V4_1 */
> +#ifdef CONFIG_NFS_V4_2
> +__be32 nfs4_callback_offload(struct cb_offloadargs *args, void *dummy,
> +				struct cb_process_state *cps)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_NFS_V4_2 */
> diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
> index 390ac9c..be5ffa1 100644
> --- a/fs/nfs/callback_xdr.c
> +++ b/fs/nfs/callback_xdr.c
> @@ -37,6 +37,9 @@
>  #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
>  #define CB_OP_NOTIFY_LOCK_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
>  #endif /* CONFIG_NFS_V4_1 */
> +#ifdef CONFIG_NFS_V4_2
> +#define CB_OP_OFFLOAD_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
> +#endif /* CONFIG_NFS_V4_2 */
>  
>  #define NFSDBG_FACILITY NFSDBG_CALLBACK
>  
> @@ -521,7 +524,72 @@ static __be32 decode_notify_lock_args(struct svc_rqst *rqstp, struct xdr_stream
>  }
>  
>  #endif /* CONFIG_NFS_V4_1 */
> +#ifdef CONFIG_NFS_V4_2
> +static __be32 decode_write_response(struct xdr_stream *xdr,
> +					struct cb_offloadargs *args)
> +{
> +	__be32 *p;
> +	__be32 dummy;
> +
> +	/* skip the always zero field */
> +	p = read_buf(xdr, 4);
> +	if (unlikely(!p))
> +		goto out;
> +	dummy = ntohl(*p++);
> +
> +	/* decode count, stable_how, verifier */
> +	p = xdr_inline_decode(xdr, 8 + 4);
> +	if (unlikely(!p))
> +		goto out;
> +	p = xdr_decode_hyper(p, &args->wr_count);
> +	args->wr_writeverf.committed = be32_to_cpup(p);
> +	p = xdr_inline_decode(xdr, NFS4_VERIFIER_SIZE);
> +	if (likely(p)) {
> +		memcpy(&args->wr_writeverf.verifier.data[0], p,
> +			NFS4_VERIFIER_SIZE);
> +		return 0;
> +	}
> +out:
> +	return htonl(NFS4ERR_RESOURCE);
> +}
> +
> +static __be32 decode_offload_args(struct svc_rqst *rqstp,
> +					struct xdr_stream *xdr,
> +					struct cb_offloadargs *args)
> +{
> +	__be32 *p;
> +	__be32 status;
> +
> +	/* decode fh */
> +	status = decode_fh(xdr, &args->coa_fh);
> +	if (unlikely(status != 0))
> +		return status;
> +
> +	/* decode stateid */
> +	status = decode_stateid(xdr, &args->coa_stateid);
> +	if (unlikely(status != 0))
> +		return status;
>  
> +	/* decode status */
> +	p = read_buf(xdr, 4);
> +	if (unlikely(!p))
> +		goto out;
> +	args->error = ntohl(*p++);
> +	if (!args->error) {
> +		status = decode_write_response(xdr, args);
> +		if (unlikely(status != 0))
> +			return status;
> +	} else {
> +		p = xdr_inline_decode(xdr, 8);
> +		if (unlikely(!p))
> +			goto out;
> +		p = xdr_decode_hyper(p, &args->wr_count);
> +	}
> +	return 0;
> +out:
> +	return htonl(NFS4ERR_RESOURCE);
> +}
> +#endif /* CONFIG_NFS_V4_2 */
>  static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
>  {
>  	if (unlikely(xdr_stream_encode_opaque(xdr, str, len) < 0))
> @@ -785,7 +853,10 @@ static void nfs4_cb_free_slot(struct cb_process_state *cps)
>  	if (status != htonl(NFS4ERR_OP_ILLEGAL))
>  		return status;
>  
> -	if (op_nr == OP_CB_OFFLOAD)
> +	if (op_nr == OP_CB_OFFLOAD) {
> +		*op = &callback_ops[op_nr];
> +		return htonl(NFS_OK);
> +	} else
>  		return htonl(NFS4ERR_NOTSUPP);
>  	return htonl(NFS4ERR_OP_ILLEGAL);
>  }
> @@ -982,6 +1053,13 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
>  		.res_maxsize = CB_OP_NOTIFY_LOCK_RES_MAXSZ,
>  	},
>  #endif /* CONFIG_NFS_V4_1 */
> +#ifdef CONFIG_NFS_V4_2
> +	[OP_CB_OFFLOAD] = {
> +		.process_op = (callback_process_op_t)nfs4_callback_offload,
> +		.decode_args = (callback_decode_arg_t)decode_offload_args,
> +		.res_maxsize = CB_OP_OFFLOAD_RES_MAXSZ,
> +	},
> +#endif /* CONFIG_NFS_V4_2 */
Just a heads up that the function signatures change in 4.13 and the casting is removed.  The .process_op function now expects:
    __be32 func(void *argp, void *resp, struct cb_process_state *cps);

And .decode_args is now:
    __be32 func(struct svc_rqst *rqstp, struct xdr_stream *xdr, void *argp);

Thanks,
Anna

>  };
>  
>  /*
>