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>

1 files changed, 32 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 9e2ee75e0f7c..ae21a4efe36c 100644
--- 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) {