nfsd41: Use separate DRC for setclientid

Instead of trying to share the generic 4.1 reply cache code for the
CREATE_SESSION reply cache, it's simpler to handle CREATE_SESSION
separately.

The nfs41 single slot clientid DRC holds the results of create session
processing.  CREATE_SESSION can be preceeded by a SEQUENCE operation
(an embedded CREATE_SESSION) and the create session single slot cache must be
maintained.  nfsd4_replay_cache_entry() and nfsd4_store_cache_entry() do not
implement the replay of an embedded CREATE_SESSION.

The clientid DRC slot does not need the inuse, cachethis or other fields that
the multiple slot session cache uses.  Replace the clientid DRC cache struct
nfs4_slot cache with a new nfsd4_clid_slot cache.  Save the xdr struct
nfsd4_create_session into the cache at the end of processing, and on a replay,
replace the struct for the replay request with the cached version all while
under the state lock.

nfsd4_proc_compound will handle both the solo and embedded CREATE_SESSION case
via the normal use of encode_operation.

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.

Remove the clientid DRC specific check in nfs4svc_encode_compoundres to
put the session only if cstate.session is set which will now always be true.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

5 files changed, 60 insertions, 42 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index d781658e8084..d606c6a427de 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1120,7 +1120,7 @@ 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))
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 99df8e7a687b..7729d092c8a5 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -653,8 +653,6 @@ static inline void
 free_client(struct nfs4_client *clp)
 {
         shutdown_callback_client(clp);
-        nfsd4_release_respages(clp->cl_slot.sl_cache_entry.ce_respages,
-                             clp->cl_slot.sl_cache_entry.ce_resused);
         if (clp->cl_cred.cr_group_info)
                 put_group_info(clp->cl_cred.cr_group_info);
         kfree(clp->cl_principal);
@@ -1293,12 +1291,11 @@ out_copy:
         exid->clientid.cl_boot = new->cl_clientid.cl_boot;
         exid->clientid.cl_id = new->cl_clientid.cl_id;
 
-        new->cl_slot.sl_seqid = 0;
         exid->seqid = 1;
         nfsd4_set_ex_flags(new, exid);
 
         dprintk("nfsd4_exchange_id seqid %d flags %x\n",
-                new->cl_slot.sl_seqid, new->cl_exchange_flags);
+                new->cl_cs_slot.sl_seqid, new->cl_exchange_flags);
         status = nfs_ok;
 
 out:
@@ -1334,15 +1331,35 @@ check_slot_seqid(u32 seqid, u32 slot_seqid, int slot_inuse)
         return nfserr_seq_misordered;
 }
 
+/*
+ * Cache the create session result into the create session single DRC
+ * slot cache by saving the xdr structure. sl_seqid has been set.
+ * Do this for solo or embedded create session operations.
+ */
+static void
+nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
+                           struct nfsd4_clid_slot *slot, int nfserr)
+{
+        slot->sl_status = nfserr;
+        memcpy(&slot->sl_cr_ses, cr_ses, sizeof(*cr_ses));
+}
+
+static __be32
+nfsd4_replay_create_session(struct nfsd4_create_session *cr_ses,
+                            struct nfsd4_clid_slot *slot)
+{
+        memcpy(cr_ses, &slot->sl_cr_ses, sizeof(*cr_ses));
+        return slot->sl_status;
+}
+
 __be32
 nfsd4_create_session(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
                      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_slot *slot = NULL;
+        struct nfsd4_clid_slot *cs_slot = NULL;
         int status = 0;
 
         nfs4_lock_state();
@@ -1350,25 +1367,22 @@ nfsd4_create_session(struct svc_rqst *rqstp,
         conf = find_confirmed_client(&cr_ses->clientid);
 
         if (conf) {
-                slot = &conf->cl_slot;
-                status = check_slot_seqid(cr_ses->seqid, slot->sl_seqid,
-                                          slot->sl_inuse);
+                cs_slot = &conf->cl_cs_slot;
+                status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
                 if (status == nfserr_replay_cache) {
                         dprintk("Got a create_session replay! seqid= %d\n",
-                                slot->sl_seqid);
-                        cstate->slot = slot;
-                        cstate->status = status;
+                                cs_slot->sl_seqid);
                         /* Return the cached reply status */
-                        status = nfsd4_replay_cache_entry(resp, NULL);
+                        status = nfsd4_replay_create_session(cr_ses, cs_slot);
                         goto out;
-                } else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
+                } else if (cr_ses->seqid != cs_slot->sl_seqid + 1) {
                         status = nfserr_seq_misordered;
                         dprintk("Sequence misordered!\n");
                         dprintk("Expected seqid= %d but got seqid= %d\n",
-                                slot->sl_seqid, cr_ses->seqid);
+                                cs_slot->sl_seqid, cr_ses->seqid);
                         goto out;
                 }
-                conf->cl_slot.sl_seqid++;
+                cs_slot->sl_seqid++;
         } else if (unconf) {
                 if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
                     (ip_addr != unconf->cl_addr)) {
@@ -1376,16 +1390,15 @@ nfsd4_create_session(struct svc_rqst *rqstp,
                         goto out;
                 }
 
-                slot = &unconf->cl_slot;
-                status = check_slot_seqid(cr_ses->seqid, slot->sl_seqid,
-                                          slot->sl_inuse);
+                cs_slot = &unconf->cl_cs_slot;
+                status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0);
                 if (status) {
                         /* an unconfirmed replay returns misordered */
                         status = nfserr_seq_misordered;
-                        goto out;
+                        goto out_cache;
                 }
 
-                slot->sl_seqid++; /* from 0 to 1 */
+                cs_slot->sl_seqid++; /* from 0 to 1 */
                 move_to_confirmed(unconf);
 
                 /*
@@ -1406,12 +1419,11 @@ nfsd4_create_session(struct svc_rqst *rqstp,
 
         memcpy(cr_ses->sessionid.data, conf->cl_sessionid.data,
                NFS4_MAX_SESSIONID_LEN);
-        cr_ses->seqid = slot->sl_seqid;
+        cr_ses->seqid = cs_slot->sl_seqid;
 
-        slot->sl_inuse = true;
-        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, cs_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 2dcc7feaa6ff..fdf632bf1cfe 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3313,8 +3313,7 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
                         dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
                         resp->cstate.slot->sl_inuse = 0;
                 }
-                if (resp->cstate.session)
-                        nfsd4_put_session(resp->cstate.session);
+                nfsd4_put_session(resp->cstate.session);
         }
         return 1;
 }
diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index a6c87d623891..58bb19784e12 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -127,6 +127,25 @@ struct nfsd4_channel_attrs {
         u32             rdma_attrs;
 };
 
+struct nfsd4_create_session {
+        clientid_t                      clientid;
+        struct nfs4_sessionid           sessionid;
+        u32                             seqid;
+        u32                             flags;
+        struct nfsd4_channel_attrs      fore_channel;
+        struct nfsd4_channel_attrs      back_channel;
+        u32                             callback_prog;
+        u32                             uid;
+        u32                             gid;
+};
+
+/* The single slot clientid cache structure */
+struct nfsd4_clid_slot {
+        u32                             sl_seqid;
+        __be32                          sl_status;
+        struct nfsd4_create_session     sl_cr_ses;
+};
+
 struct nfsd4_session {
         struct kref             se_ref;
         struct list_head        se_hash;        /* hash by sessionid */
@@ -193,7 +212,7 @@ struct nfs4_client {
 
         /* for nfs41 */
         struct list_head        cl_sessions;
-        struct nfsd4_slot       cl_slot;        /* create_session slot */
+        struct nfsd4_clid_slot  cl_cs_slot;     /* create_session slot */
         u32                     cl_exchange_flags;
         struct nfs4_sessionid   cl_sessionid;
 };
diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index 2bacf7535069..5e4beb0deb80 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -366,18 +366,6 @@ struct nfsd4_exchange_id {
         int             spa_how;
 };
 
-struct nfsd4_create_session {
-        clientid_t              clientid;
-        struct nfs4_sessionid   sessionid;
-        u32                     seqid;
-        u32                     flags;
-        struct nfsd4_channel_attrs fore_channel;
-        struct nfsd4_channel_attrs back_channel;
-        u32                     callback_prog;
-        u32                     uid;
-        u32                     gid;
-};
-
 struct nfsd4_sequence {
         struct nfs4_sessionid   sessionid;              /* request/response */
         u32                     seqid;                  /* request/response */