[PATCH 02/29] nfsd41: encode create_session result into cache

[andros@netapp.com]

From: Andy Adamson <andros@netapp.com>

CREATE_SESSION can be preceeded by a SEQUENCE operation and the
create session single slot cache must be maintained. Encode the results of
a create session call into the cache at the end of processing.

The create session result will also be encoded into the RPC response, and if
it is preceeded by a SEQUENCE operation, will also be encoded into the
session slot table cache.

Errors that do not change the create session cache:
A create session NFS4ERR_STALE_CLIENTID error means that a client record
(and associated create session slot) could not be found and therefore can't
be changed.  NFSERR_SEQ_MISORDERED errors do not change the slot cache.

All other errors get cached.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfsd/nfs4state.c       |    6 +++++-
 fs/nfsd/nfs4xdr.c         |   19 +++++++++++++++++++
 include/linux/nfsd/xdr4.h |    2 ++
 3 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 27ad37f..279b47e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1377,7 +1377,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
 		if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
 		    (ip_addr != unconf->cl_addr)) {
 			status = nfserr_clid_inuse;
-			goto out;
+			goto out_cache;
 		}
 
 		slot = &unconf->cl_slot;
@@ -1424,6 +1424,10 @@ nfsd4_create_session(struct svc_rqst *rqstp,
 	cstate->slot = slot;
 	/* Ensure a page is used for the cache */
 	slot->sl_cache_entry.ce_cachethis = 1;
+out_cache:
+	/* cache solo and embedded create sessions under the state lock */
+	nfsd4_cache_create_session(cr_ses, slot, status);
+
 out:
 	nfs4_unlock_state();
 	dprintk("%s returns %d\n", __func__, ntohl(status));
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b2f8d74..6b34fac 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3046,6 +3046,25 @@ nfsd4_encode_create_session(struct nfsd4_compoundres *resp, int nfserr,
 	return 0;
 }
 
+/*
+ * Encode the create_session result into the create session single DRC
+ * slot cache. Do this for solo or embedded create session operations.
+ */
+void
+nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
+			   struct nfsd4_slot *slot, int nfserr)
+{
+	struct nfsd4_cache_entry *entry = &slot->sl_cache_entry;
+	__be32 *p = (__be32 *)entry->ce_datav.iov_base;
+	struct nfsd4_compoundres tmp = {
+		.p = p,
+		.end = p + XDR_QUADLEN(CS_MAX_ENC_SZ),
+	}, *resp = &tmp;
+
+	entry->ce_status = nfsd4_encode_create_session(resp, nfserr, cr_ses);
+	entry->ce_datav.iov_len = (char *)resp->p - (char *)p;
+}
+
 static __be32
 nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, int nfserr,
 			     struct nfsd4_destroy_session *destroy_session)
diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index afd4464..cc50ca0 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -517,6 +517,8 @@ extern __be32 nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
 extern void nfsd4_store_cache_entry(struct nfsd4_compoundres *resp);
 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_slot *slot, int nfserr);
 extern __be32 nfsd4_exchange_id(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *,
 struct nfsd4_exchange_id *);
-- 
1.5.4.3