nfs41: Check slot table for referring calls

Traverse a list of referring calls and look for a session/slot/seq number
match.

Signed-off-by: Mike Sager <sager@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index defa9b4c470e..631b44c1439b 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -225,6 +225,61 @@ validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
         return NULL;
 }
 
+/*
+ * For each referring call triple, check the session's slot table for
+ * a match.  If the slot is in use and the sequence numbers match, the
+ * client is still waiting for a response to the original request.
+ */
+static bool referring_call_exists(struct nfs_client *clp,
+                                  uint32_t nrclists,
+                                  struct referring_call_list *rclists)
+{
+        bool status = 0;
+        int i, j;
+        struct nfs4_session *session;
+        struct nfs4_slot_table *tbl;
+        struct referring_call_list *rclist;
+        struct referring_call *ref;
+
+        /*
+         * XXX When client trunking is implemented, this becomes
+         * a session lookup from within the loop
+         */
+        session = clp->cl_session;
+        tbl = &session->fc_slot_table;
+
+        for (i = 0; i < nrclists; i++) {
+                rclist = &rclists[i];
+                if (memcmp(session->sess_id.data,
+                           rclist->rcl_sessionid.data,
+                           NFS4_MAX_SESSIONID_LEN) != 0)
+                        continue;
+
+                for (j = 0; j < rclist->rcl_nrefcalls; j++) {
+                        ref = &rclist->rcl_refcalls[j];
+
+                        dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u "
+                                "slotid %u\n", __func__,
+                                ((u32 *)&rclist->rcl_sessionid.data)[0],
+                                ((u32 *)&rclist->rcl_sessionid.data)[1],
+                                ((u32 *)&rclist->rcl_sessionid.data)[2],
+                                ((u32 *)&rclist->rcl_sessionid.data)[3],
+                                ref->rc_sequenceid, ref->rc_slotid);
+
+                        spin_lock(&tbl->slot_tbl_lock);
+                        status = (test_bit(ref->rc_slotid, tbl->used_slots) &&
+                                  tbl->slots[ref->rc_slotid].seq_nr ==
+                                        ref->rc_sequenceid);
+                        spin_unlock(&tbl->slot_tbl_lock);
+                        if (status)
+                                goto out;
+                }
+        }
+
+out:
+        return status;
+}
+
 /* FIXME: referring calls should be processed */
 unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
                                 struct cb_sequenceres *res)