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

From: "William A. (Andy) Adamson" <androsadamson@gmail.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: linux-nfs@vger.kernel.org, pnfs@linux-nfs.org
Subject: Re: [pnfs] [PATCH 07/31] nfsd41: replay solo and embedded create session
Date: Mon, 18 May 2009 10:02:25 -0400	[thread overview]
Message-ID: <89c397150905180702x6cecb802md9fed2f7f81e9aa1@mail.gmail.com> (raw)
In-Reply-To: <20090515230821.GH26389@fieldses.org>

On Fri, May 15, 2009 at 7:08 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> 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.

I believe we will still need the new internal case.
When the sequence operation replay case gets hit in
nfsd4_proc_compound, the entire reply has been constructed from the
cache, so the sequence operation replay exits nfsd4_proc_compound
processing.

In the create session replay case, only the create session operation
will be reconstructed from the cache, and it might be an embedded
create session (part of another sessions sequence compound) and so the
rest of the operations in that compound would need to be processed.
So, the create session replay does not exit nfsd4_proc_compound
processing.

-->Andy
>
> --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
>>
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