nfs41: call free slot from nfs4_restart_rpc

nfs41_sequence_free_slot can be called multiple times on SEQUENCE operation
errors.
No reason to inline nfs4_restart_rpc
Reported-by: Trond Myklebust <trond.myklebust@netapp.com>

nfs_writeback_done and nfs_readpage_retry call nfs4_restart_rpc outside the
error handler, and the slot is not freed prior to restarting in the rpc_prepare
state during session reset.

Fix this by moving the call to nfs41_sequence_free_slot from the error
path of nfs41_sequence_done into nfs4_restart_rpc, and by removing the test
for NFS4CLNT_SESSION_SETUP.
Always free slot and goto the rpc prepare state on async errors.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/internal.h

@@ -177,26 +177,14 @@ extern __be32 * nfs_decode_dirent(__be32 *, struct nfs_entry *, int);
 extern struct rpc_procinfo nfs3_procedures[];
 extern __be32 *nfs3_decode_dirent(__be32 *, struct nfs_entry *, int);
 
-/* nfs4proc.c */
-static inline void nfs4_restart_rpc(struct rpc_task *task,
-				    const struct nfs_client *clp)
-{
-#ifdef CONFIG_NFS_V4_1
-	if (nfs4_has_session(clp) &&
-	    test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state)) {
-		rpc_restart_call_prepare(task);
-		return;
-	}
-#endif /* CONFIG_NFS_V4_1 */
-	rpc_restart_call(task);
-}
-
 /* nfs4xdr.c */
 #ifdef CONFIG_NFS_V4
 extern __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus);
 #endif
 
 /* nfs4proc.c */
+extern void nfs4_restart_rpc(struct rpc_task *, const struct nfs_client *,
+			     struct nfs4_sequence_res *);
 #ifdef CONFIG_NFS_V4
 extern struct rpc_procinfo nfs4_procedures[];
 #endif

fs/nfs/nfs4proc.c

@@ -644,6 +644,19 @@ static void nfs4_sequence_done(const struct nfs_server *server,
 #endif /* CONFIG_NFS_V4_1 */
 }
 
+void nfs4_restart_rpc(struct rpc_task *task, const struct nfs_client *clp,
+		      struct nfs4_sequence_res *res)
+{
+#ifdef CONFIG_NFS_V4_1
+	if (nfs4_has_session(clp)) {
+		nfs41_sequence_free_slot(clp, res);
+		rpc_restart_call_prepare(task);
+		return;
+	}
+#endif /* CONFIG_NFS_V4_1 */
+	rpc_restart_call(task);
+}
+
 /* no restart, therefore free slot here */
 static void nfs4_sequence_done_free_slot(const struct nfs_server *server,
 					 struct nfs4_sequence_res *res,
@@ -1750,7 +1763,8 @@ static void nfs4_close_done(struct rpc_task *task, void *data)
 				break;
 		default:
 			if (nfs4_async_handle_error(task, server, state) == -EAGAIN) {
-				nfs4_restart_rpc(task, server->nfs_client);
+				nfs4_restart_rpc(task, server->nfs_client,
+						 &calldata->res.seq_res);
 				return;
 			}
 	}
@@ -2988,7 +3002,7 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
 	nfs4_sequence_done(server, &data->res.seq_res, task->tk_status);
 
 	if (nfs4_async_handle_error(task, server, data->args.context->state) == -EAGAIN) {
-		nfs4_restart_rpc(task, server->nfs_client);
+		nfs4_restart_rpc(task, server->nfs_client, &data->res.seq_res);
 		return -EAGAIN;
 	}
 
@@ -3013,7 +3027,8 @@ static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
 			   task->tk_status);
 
 	if (nfs4_async_handle_error(task, NFS_SERVER(inode), data->args.context->state) == -EAGAIN) {
-		nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client);
+		nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client,
+				 &data->res.seq_res);
 		return -EAGAIN;
 	}
 	if (task->tk_status >= 0) {
@@ -3041,7 +3056,8 @@ static int nfs4_commit_done(struct rpc_task *task, struct nfs_write_data *data)
 	nfs4_sequence_done(NFS_SERVER(inode), &data->res.seq_res,
 			   task->tk_status);
 	if (nfs4_async_handle_error(task, NFS_SERVER(inode), NULL) == -EAGAIN) {
-		nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client);
+		nfs4_restart_rpc(task, NFS_SERVER(inode)->nfs_client,
+				 &data->res.seq_res);
 		return -EAGAIN;
 	}
 	nfs4_sequence_free_slot(NFS_SERVER(inode)->nfs_client,
@@ -3755,7 +3771,8 @@ static void nfs4_locku_done(struct rpc_task *task, void *data)
 		default:
 			if (nfs4_async_handle_error(task, calldata->server, NULL) == -EAGAIN)
 				nfs4_restart_rpc(task,
-						calldata->server->nfs_client);
+						 calldata->server->nfs_client,
+						 &calldata->res.seq_res);
 	}
 	nfs4_sequence_free_slot(calldata->server->nfs_client,
 				&calldata->res.seq_res);
@@ -4890,7 +4907,7 @@ void nfs41_sequence_call_done(struct rpc_task *task, void *data)
 
 		if (_nfs4_async_handle_error(task, NULL, clp, NULL)
 								== -EAGAIN) {
-			nfs4_restart_rpc(task, clp);
+			nfs4_restart_rpc(task, clp, task->tk_msg.rpc_resp);
 			return;
 		}
 	}

fs/nfs/read.c

@@ -368,7 +368,8 @@ static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data
 	argp->offset += resp->count;
 	argp->pgbase += resp->count;
 	argp->count -= resp->count;
-	nfs4_restart_rpc(task, NFS_SERVER(data->inode)->nfs_client);
+	nfs4_restart_rpc(task, NFS_SERVER(data->inode)->nfs_client,
+			 &data->res.seq_res);
 	return;
 out:
 	nfs4_sequence_free_slot(NFS_SERVER(data->inode)->nfs_client,

fs/nfs/unlink.c

@@ -81,9 +81,11 @@ static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs_unlinkdata *data = calldata;
 	struct inode *dir = data->dir;
+	struct nfs_removeres *res = task->tk_msg.rpc_resp;
 
 	if (!NFS_PROTO(dir)->unlink_done(task, dir))
-		nfs4_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
+		nfs4_restart_rpc(task, NFS_SERVER(dir)->nfs_client,
+				 &res->seq_res);
 }
 
 /**

fs/nfs/write.c

@@ -1216,7 +1216,8 @@ int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
 				 */
 				argp->stable = NFS_FILE_SYNC;
 			}
-			nfs4_restart_rpc(task, server->nfs_client);
+			nfs4_restart_rpc(task, server->nfs_client,
+					 &data->res.seq_res);
 			return -EAGAIN;
 		}
 		if (time_before(complain, jiffies)) {