Re: [PATCH 07/31] nfsd41: replay solo and embedded create session

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

On Tue, Apr 28, 2009 at 12:59:41PM -0400, andros@netapp.com wrote:
> From: Andy Adamson <andros@netapp.com>
> 
> CREATE_SESSION can be preceeded by a SEQUENCE operation (an embedded
> CREATE_SESSION) and the create session single slot cache must be maintained.
> Always replay a create session from nfsd4_replay_create_session(). Leave
> nfsd4_store_cache_entry() for session (sequence operation) replays.
> 
> Set cstate->status to a new internal error, nfserr_replay_clientid_cache, and
> change the logic in nfsd4_proc_compound so that CREATE_SESSION replays replace
> encode_operation.
> The new internal error is needed to differentiate between an embedded
> CREATE_SESSION replay and a SEQUENCE replay.

And making the clientid_cache cache just the unencoded
nfsd4_create_session would avoid the need for this special case, since
it would look to nfsd4_proc_compound() like any other create_session.

--b.

> 
> Signed-off-by: Andy Adamson <andros@netapp.com>
> ---
>  fs/nfsd/nfs4proc.c        |    9 +++++++--
>  fs/nfsd/nfs4state.c       |    5 +++++
>  fs/nfsd/nfs4xdr.c         |   17 +++++++++++++++++
>  include/linux/nfsd/nfsd.h |    2 ++
>  include/linux/nfsd/xdr4.h |    2 ++
>  5 files changed, 33 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b2883e9..32d5866 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -996,7 +996,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
>  			BUG_ON(op->status == nfs_ok);
>  
>  encode_op:
> -		/* Only from SEQUENCE or CREATE_SESSION */
> +		/* Only from SEQUENCE */
>  		if (resp->cstate.status == nfserr_replay_cache) {
>  			dprintk("%s NFS4.1 replay from cache\n", __func__);
>  			if (nfsd4_not_cached(resp))
> @@ -1005,7 +1005,12 @@ encode_op:
>  				status = op->status;
>  			goto out;
>  		}
> -		if (op->status == nfserr_replay_me) {
> +		/* Only from CREATE_SESSION */
> +		if (resp->cstate.status == nfserr_replay_clientid_cache) {
> +			dprintk("%s NFS4.1 replay from clientid cache\n",
> +				__func__);
> +			status = op->status;
> +		} else if (op->status == nfserr_replay_me) {
>  			op->replay = &cstate->replay_owner->so_replay;
>  			nfsd4_encode_replay(resp, op);
>  			status = op->status = op->replay->rp_status;
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index de7cc51..e216169 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1350,6 +1350,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>  		     struct nfsd4_create_session *cr_ses)
>  {
>  	u32 ip_addr = svc_addr_in(rqstp)->sin_addr.s_addr;
> +	struct nfsd4_compoundres *resp = rqstp->rq_resp;
>  	struct nfs4_client *conf, *unconf;
>  	struct nfsd4_clid_slot *slot = NULL;
>  	int status = 0;
> @@ -1364,6 +1365,10 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>  		if (status == nfserr_replay_cache) {
>  			dprintk("Got a create_session replay! seqid= %d\n",
>  				slot->sl_seqid);
> +			cstate->status = nfserr_replay_clientid_cache;
> +			/* Return the cached reply status */
> +			status = nfsd4_replay_create_session(resp, slot);
> +			goto out;
>  		} else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
>  			status = nfserr_seq_misordered;
>  			dprintk("Sequence misordered!\n");
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 1dfec1d..238612e 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3064,6 +3064,23 @@ nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
>  	slot->sl_datalen = (char *)resp->p - (char *)p;
>  }
>  
> +__be32
> +nfsd4_replay_create_session(struct nfsd4_compoundres *resp,
> +			    struct nfsd4_clid_slot *slot)
> +{
> +	__be32 *p;
> +
> +	RESERVE_SPACE(8);
> +	WRITE32(OP_CREATE_SESSION);
> +	*p++ = slot->sl_status; /* already in network byte order */
> +	ADJUST_ARGS();
> +
> +	memcpy(resp->p, slot->sl_data, slot->sl_datalen);
> +	p += XDR_QUADLEN(slot->sl_datalen);
> +	ADJUST_ARGS();
> +	return slot->sl_status;
> +}
> +
>  static __be32
>  nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, int nfserr,
>  			     struct nfsd4_destroy_session *destroy_session)
> diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
> index 2b49d67..9cd6399 100644
> --- a/include/linux/nfsd/nfsd.h
> +++ b/include/linux/nfsd/nfsd.h
> @@ -301,6 +301,8 @@ void		nfsd_lockd_shutdown(void);
>  #define	nfserr_replay_me	cpu_to_be32(11001)
>  /* nfs41 replay detected */
>  #define	nfserr_replay_cache	cpu_to_be32(11002)
> +/* nfs41 clientid cache replay detected */
> +#define	nfserr_replay_clientid_cache	cpu_to_be32(11003)
>  
>  /* Check for dir entries '.' and '..' */
>  #define isdotent(n, l)	(l < 3 && n[0] == '.' && (l == 1 || n[1] == '.'))
> diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
> index 21e0b73..ac00985 100644
> --- a/include/linux/nfsd/xdr4.h
> +++ b/include/linux/nfsd/xdr4.h
> @@ -519,6 +519,8 @@ extern __be32 nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
>  		struct nfsd4_sequence *seq);
>  extern void nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
>  		struct nfsd4_clid_slot *slot, int nfserr);
> +extern __be32 nfsd4_replay_create_session(struct nfsd4_compoundres *resp,
> +		struct nfsd4_clid_slot *slot);
>  extern __be32 nfsd4_exchange_id(struct svc_rqst *rqstp,
>  		struct nfsd4_compound_state *,
>  struct nfsd4_exchange_id *);
> -- 
> 1.5.4.3
>