NFSv4.1 free slot before resending I/O to MDS

Fix a dynamic session slot leak where a slot is preallocated and I/O is
resent through the MDS.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4_fs.h

@@ -270,6 +270,7 @@ static inline struct nfs4_session *nfs4_get_session(const struct nfs_server *ser
 extern int nfs41_setup_sequence(struct nfs4_session *session,
 		struct nfs4_sequence_args *args, struct nfs4_sequence_res *res,
 		struct rpc_task *task);
+extern int nfs41_sequence_done(struct rpc_task *, struct nfs4_sequence_res *);
 extern int nfs4_proc_create_session(struct nfs_client *, struct rpc_cred *);
 extern int nfs4_proc_destroy_session(struct nfs4_session *, struct rpc_cred *);
 extern int nfs4_proc_get_lease_time(struct nfs_client *clp,

fs/nfs/nfs4filelayout.c

@@ -335,8 +335,11 @@ static void filelayout_read_call_done(struct rpc_task *task, void *data)
 	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
 
 	if (test_bit(NFS_IOHDR_REDO, &rdata->header->flags) &&
-	    task->tk_status == 0)
+	    task->tk_status == 0) {
+		if (rdata->res.seq_res.sr_slot != NULL)
+			nfs41_sequence_done(task, &rdata->res.seq_res);
 		return;
+	}
 
 	/* Note this may cause RPC to be resent */
 	rdata->header->mds_ops->rpc_call_done(task, data);
@@ -442,8 +445,11 @@ static void filelayout_write_call_done(struct rpc_task *task, void *data)
 	struct nfs_write_data *wdata = data;
 
 	if (test_bit(NFS_IOHDR_REDO, &wdata->header->flags) &&
-	    task->tk_status == 0)
+	    task->tk_status == 0) {
+		if (wdata->res.seq_res.sr_slot != NULL)
+			nfs41_sequence_done(task, &wdata->res.seq_res);
 		return;
+	}
 
 	/* Note this may cause RPC to be resent */
 	wdata->header->mds_ops->rpc_call_done(task, data);

fs/nfs/nfs4proc.c

@@ -592,7 +592,7 @@ out_unlock:
 		nfs41_server_notify_highest_slotid_update(session->clp);
 }
 
-static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
+int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
 {
 	struct nfs4_session *session;
 	struct nfs4_slot *slot;
@@ -692,6 +692,7 @@ out_retry:
 	rpc_delay(task, NFS4_POLL_RETRY_MAX);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(nfs41_sequence_done);
 
 static int nfs4_sequence_done(struct rpc_task *task,
 			       struct nfs4_sequence_res *res)