nfsd41: Add a create session replay cache

Replace the nfs4_client cl_seqid field with a single struct nfs41_slot used
for the create session replay cache.

The CREATE_SESSION slot sets the sl_session pointer to NULL. Otherwise, the
slot and it's replay cache are used just like the session slots.

Fix unconfirmed create_session replay response by initializing the
create_session slot sequence id to 0.

A future patch will set the CREATE_SESSION cache when a SEQUENCE operation
preceeds the CREATE_SESSION operation. This compound is currently only cached
in the session slot table.

Signed-off-by: Andy Adamson<andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: use bool inuse for slot state]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: revert portion of nfsd4_set_cache_entry]
Signed-off-by: Andy Adamson <andros@netpp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

2 files changed, 28 insertions, 13 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 463ae39df148..58f9797eb09e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -649,6 +649,8 @@ 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);
@@ -1263,11 +1265,12 @@ out_copy:
         exid->clientid.cl_boot = new->cl_clientid.cl_boot;
         exid->clientid.cl_id = new->cl_clientid.cl_id;
 
-        new->cl_seqid = exid->seqid = 1;
+        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_seqid, new->cl_exchange_flags);
+                new->cl_slot.sl_seqid, new->cl_exchange_flags);
         status = nfs_ok;
 
 out:
@@ -1309,7 +1312,9 @@ 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_slot *slot = NULL;
         int status = 0;
 
         nfs4_lock_state();
@@ -1317,19 +1322,24 @@ nfsd4_create_session(struct svc_rqst *rqstp,
         conf = find_confirmed_client(&cr_ses->clientid);
 
         if (conf) {
-                status = nfs_ok;
-                if (conf->cl_seqid == cr_ses->seqid) {
+                slot = &conf->cl_slot;
+                status = check_slot_seqid(cr_ses->seqid, slot);
+                if (status == nfserr_replay_cache) {
                         dprintk("Got a create_session replay! seqid= %d\n",
-                                conf->cl_seqid);
-                        goto out_replay;
-                } else if (cr_ses->seqid != conf->cl_seqid + 1) {
+                                slot->sl_seqid);
+                        cstate->slot = slot;
+                        cstate->status = status;
+                        /* Return the cached reply status */
+                        status = nfsd4_replay_cache_entry(resp);
+                        goto out;
+                } else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
                         status = nfserr_seq_misordered;
                         dprintk("Sequence misordered!\n");
                         dprintk("Expected seqid= %d but got seqid= %d\n",
-                                conf->cl_seqid, cr_ses->seqid);
+                                slot->sl_seqid, cr_ses->seqid);
                         goto out;
                 }
-                conf->cl_seqid++;
+                conf->cl_slot.sl_seqid++;
         } else if (unconf) {
                 if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
                     (ip_addr != unconf->cl_addr)) {
@@ -1337,11 +1347,15 @@ nfsd4_create_session(struct svc_rqst *rqstp,
                         goto out;
                 }
 
-                if (unconf->cl_seqid != cr_ses->seqid) {
+                slot = &unconf->cl_slot;
+                status = check_slot_seqid(cr_ses->seqid, slot);
+                if (status) {
+                        /* an unconfirmed replay returns misordered */
                         status = nfserr_seq_misordered;
                         goto out;
                 }
 
+                slot->sl_seqid++; /* from 0 to 1 */
                 move_to_confirmed(unconf);
 
                 /*
@@ -1360,11 +1374,12 @@ nfsd4_create_session(struct svc_rqst *rqstp,
         if (status)
                 goto out;
 
-out_replay:
         memcpy(cr_ses->sessionid.data, conf->cl_sessionid.data,
                NFS4_MAX_SESSIONID_LEN);
-        cr_ses->seqid = conf->cl_seqid;
+        cr_ses->seqid = slot->sl_seqid;
 
+        slot->sl_inuse = true;
+        cstate->slot = slot;
 out:
         nfs4_unlock_state();
         dprintk("%s returns %d\n", __func__, ntohl(status));
diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index 692edf4c2e7c..f063df7ad134 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -190,7 +190,7 @@ struct nfs4_client {
 
         /* for nfs41 */
         struct list_head        cl_sessions;
-        u32                     cl_seqid;       /* seqid for create_session */
+        struct nfsd4_slot       cl_slot;        /* create_session slot */
         u32                     cl_exchange_flags;
         struct nfs4_sessionid   cl_sessionid;
 };