nfsd41: non-page DRC for solo sequence responses

A session inactivity time compound (lease renewal) or a compound where the
sequence operation has sa_cachethis set to FALSE do not require any pages
to be held in the v4.1 DRC. This is because struct nfsd4_slot is already
caching the session information.

Add logic to the nfs41 server to not cache response pages for solo sequence
responses.

Return nfserr_replay_uncached_rep on the operation following the sequence
operation when sa_cachethis is FALSE.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: use cstate session in nfsd4_replay_cache_entry]
[nfsd41: rename nfsd4_no_page_in_cache]
[nfsd41 rename nfsd4_enc_no_page_replay]
[nfsd41 nfsd4_is_solo_sequence]
[nfsd41 change nfsd4_not_cached return]
Signed-off-by: Andy Adamson <andros@netapp.com>
[changed return type to bool]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41 drop parens in nfsd4_is_solo_sequence call]
Signed-off-by: Andy Adamson <andros@netapp.com>
[changed "== 0" to "!"]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 9e2ee75..ae21a4e 100644 (file)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -828,6 +828,34 @@ static struct nfsd4_operation nfsd4_ops[];
 static const char *nfsd4_op_name(unsigned opnum);
 
 /*
+ * This is a replay of a compound for which no cache entry pages
+ * were used. Encode the sequence operation, and if cachethis is FALSE
+ * encode the uncache rep error on the next operation.
+ */
+static __be32
+nfsd4_enc_uncached_replay(struct nfsd4_compoundargs *args,
+                        struct nfsd4_compoundres *resp)
+{
+       struct nfsd4_op *op;
+
+       dprintk("--> %s resp->opcnt %d ce_cachethis %u \n", __func__,
+               resp->opcnt, resp->cstate.slot->sl_cache_entry.ce_cachethis);
+
+       /* Encode the replayed sequence operation */
+       BUG_ON(resp->opcnt != 1);
+       op = &args->ops[resp->opcnt - 1];
+       nfsd4_encode_operation(resp, op);
+
+       /*return nfserr_retry_uncached_rep in next operation. */
+       if (resp->cstate.slot->sl_cache_entry.ce_cachethis == 0) {
+               op = &args->ops[resp->opcnt++];
+               op->status = nfserr_retry_uncached_rep;
+               nfsd4_encode_operation(resp, op);
+       }
+       return op->status;
+}
+
+/*
  * Enforce NFSv4.1 COMPOUND ordering rules.
  *
  * TODO:
@@ -895,7 +923,6 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
                dprintk("nfsv4 compound op #%d/%d: %d (%s)\n",
                        resp->opcnt, args->opcnt, op->opnum,
                        nfsd4_op_name(op->opnum));
-
                /*
                 * The XDR decode routines may have pre-set op->status;
                 * for example, if there is a miscellaneous XDR error
@@ -939,7 +966,10 @@ encode_op:
                /* Only from SEQUENCE or CREATE_SESSION */
                if (resp->cstate.status == nfserr_replay_cache) {
                        dprintk("%s NFS4.1 replay from cache\n", __func__);
-                       status = op->status;
+                       if (nfsd4_not_cached(resp))
+                               status = nfsd4_enc_uncached_replay(args, resp);
+                       else
+                               status = op->status;
                        goto out;
                }
                if (op->status == nfserr_replay_me) {

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 58f9797..04a395f 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1049,17 +1049,31 @@ nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
        /* Don't cache a failed OP_SEQUENCE. */
        if (resp->opcnt == 1 && op->opnum == OP_SEQUENCE && resp->cstate.status)
                return;
+
        nfsd4_release_respages(entry->ce_respages, entry->ce_resused);
+       entry->ce_opcnt = resp->opcnt;
+       entry->ce_status = resp->cstate.status;
+
+       /*
+        * Don't need a page to cache just the sequence operation - the slot
+        * does this for us!
+        */
+
+       if (nfsd4_not_cached(resp)) {
+               entry->ce_resused = 0;
+               entry->ce_rpchdrlen = 0;
+               dprintk("%s Just cache SEQUENCE. ce_cachethis %d\n", __func__,
+                       resp->cstate.slot->sl_cache_entry.ce_cachethis);
+               return;
+       }
        entry->ce_resused = rqstp->rq_resused;
        if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
                entry->ce_resused = NFSD_PAGES_PER_SLOT + 1;
        nfsd4_copy_pages(entry->ce_respages, rqstp->rq_respages,
                         entry->ce_resused);
-       entry->ce_status = resp->cstate.status;
        entry->ce_datav.iov_base = resp->cstate.statp;
        entry->ce_datav.iov_len = resv->iov_len - ((char *)resp->cstate.statp -
                                (char *)page_address(rqstp->rq_respages[0]));
-       entry->ce_opcnt = resp->opcnt;
        /* Current request rpc header length*/
        entry->ce_rpchdrlen = (char *)resp->cstate.statp -
                                (char *)page_address(rqstp->rq_respages[0]);
@@ -1096,13 +1110,28 @@ nfsd41_copy_replay_data(struct nfsd4_compoundres *resp,
  * cached page.  Replace any futher replay pages from the cache.
  */
 __be32
-nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp)
+nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
+                        struct nfsd4_sequence *seq)
 {
        struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
        __be32 status;
 
        dprintk("--> %s entry %p\n", __func__, entry);
 
+       /*
+        * If this is just the sequence operation, we did not keep
+        * a page in the cache entry because we can just use the
+        * slot info stored in struct nfsd4_sequence that was checked
+        * against the slot in nfsd4_sequence().
+        *
+        * This occurs when seq->cachethis is FALSE, or when the client
+        * session inactivity timer fires and a solo sequence operation
+        * is sent (lease renewal).
+        */
+       if (seq && nfsd4_not_cached(resp)) {
+               seq->maxslots = resp->cstate.session->se_fnumslots;
+               return nfs_ok;
+       }
 
        if (!nfsd41_copy_replay_data(resp, entry)) {
                /*
@@ -1330,7 +1359,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
                        cstate->slot = slot;
                        cstate->status = status;
                        /* Return the cached reply status */
-                       status = nfsd4_replay_cache_entry(resp);
+                       status = nfsd4_replay_cache_entry(resp, NULL);
                        goto out;
                } else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
                        status = nfserr_seq_misordered;
@@ -1380,6 +1409,8 @@ nfsd4_create_session(struct svc_rqst *rqstp,
 
        slot->sl_inuse = true;
        cstate->slot = slot;
+       /* Ensure a page is used for the cache */
+       slot->sl_cache_entry.ce_cachethis = 1;
 out:
        nfs4_unlock_state();
        dprintk("%s returns %d\n", __func__, ntohl(status));
@@ -1425,8 +1456,8 @@ nfsd4_sequence(struct svc_rqst *rqstp,
                cstate->slot = slot;
                cstate->session = session;
                /* Return the cached reply status and set cstate->status
-                * for nfsd4_svc_encode_compoundres processing*/
-               status = nfsd4_replay_cache_entry(resp);
+                * for nfsd4_svc_encode_compoundres processing */
+               status = nfsd4_replay_cache_entry(resp, seq);
                cstate->status = nfserr_replay_cache;
                goto replay_cache;
        }
@@ -1436,6 +1467,10 @@ nfsd4_sequence(struct svc_rqst *rqstp,
        /* Success! bump slot seqid */
        slot->sl_inuse = true;
        slot->sl_seqid = seq->seqid;
+       slot->sl_cache_entry.ce_cachethis = seq->cachethis;
+       /* Always set the cache entry cachethis for solo sequence */
+       if (nfsd4_is_solo_sequence(resp))
+               slot->sl_cache_entry.ce_cachethis = 1;
 
        cstate->slot = slot;
        cstate->session = session;

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 671f9b9..64bc215 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2975,7 +2975,7 @@ nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, int nfserr,
        return nfserr;
 }
 
-static __be32
+__be32
 nfsd4_encode_sequence(struct nfsd4_compoundres *resp, int nfserr,
                      struct nfsd4_sequence *seq)
 {
@@ -3192,7 +3192,8 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
        iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
        BUG_ON(iov->iov_len > PAGE_SIZE);
        if (resp->cstate.slot != NULL) {
-               if (resp->cstate.status == nfserr_replay_cache) {
+               if (resp->cstate.status == nfserr_replay_cache &&
+                               !nfsd4_not_cached(resp)) {
                        iov->iov_len = resp->cstate.iovlen;
                } else {
                        nfsd4_store_cache_entry(resp);

diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index f063df7..18dcffa 100644 (file)
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -110,6 +110,7 @@ struct nfsd4_cache_entry {
        __be32          ce_status;
        struct kvec     ce_datav; /* encoded NFSv4.1 data in rq_res.head[0] */
        struct page     *ce_respages[NFSD_PAGES_PER_SLOT + 1];
+       int             ce_cachethis;
        short           ce_resused;
        int             ce_opcnt;
        int             ce_rpchdrlen;

diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index 9468829..4861888 100644 (file)
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -480,6 +480,18 @@ struct nfsd4_compoundres {
        struct nfsd4_compound_state     cstate;
 };
 
+static inline bool nfsd4_is_solo_sequence(struct nfsd4_compoundres *resp)
+{
+       struct nfsd4_compoundargs *args = resp->rqstp->rq_argp;
+       return args->opcnt == 1;
+}
+
+static inline bool nfsd4_not_cached(struct nfsd4_compoundres *resp)
+{
+       return !resp->cstate.slot->sl_cache_entry.ce_cachethis ||
+                       nfsd4_is_solo_sequence(resp);
+}
+
 #define NFS4_SVC_XDRSIZE               sizeof(struct nfsd4_compoundargs)
 
 static inline void
@@ -510,7 +522,8 @@ extern __be32 nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *,
                struct nfsd4_setclientid_confirm *setclientid_confirm);
 extern void nfsd4_store_cache_entry(struct nfsd4_compoundres *resp);
-extern __be32 nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp);
+extern __be32 nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
+               struct nfsd4_sequence *seq);
 extern __be32 nfsd4_exchange_id(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *,
 struct nfsd4_exchange_id *);