NFSv4.1: Pin the inode and super block in asynchronous layoutcommit

If we're sending an asynchronous layoutcommit, then we need to ensure
that the inode and the super block remain pinned.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: NPeng Tao <tao.peng@primarydata.com>

fs/nfs/nfs4proc.c

@@ -7989,6 +7989,7 @@ static void nfs4_layoutcommit_release(void *calldata)
 	nfs_post_op_update_inode_force_wcc(data->args.inode,
 					   data->res.fattr);
 	put_rpccred(data->cred);
+	nfs_iput_and_deactive(data->inode);
 	kfree(data);
 }
 
@@ -8013,7 +8014,6 @@ nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data, bool sync)
 		.rpc_message = &msg,
 		.callback_ops = &nfs4_layoutcommit_ops,
 		.callback_data = data,
-		.flags = RPC_TASK_ASYNC,
 	};
 	struct rpc_task *task;
 	int status = 0;
@@ -8024,18 +8024,21 @@ nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data, bool sync)
 		data->args.lastbytewritten,
 		data->args.inode->i_ino);
 
+	if (!sync) {
+		data->inode = nfs_igrab_and_active(data->args.inode);
+		if (data->inode == NULL) {
+			nfs4_layoutcommit_release(data);
+			return -EAGAIN;
+		}
+		task_setup_data.flags = RPC_TASK_ASYNC;
+	}
 	nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
 	task = rpc_run_task(&task_setup_data);
 	if (IS_ERR(task))
 		return PTR_ERR(task);
-	if (sync == false)
-		goto out;
-	status = nfs4_wait_for_completion_rpc_task(task);
-	if (status != 0)
-		goto out;
-	status = task->tk_status;
+	if (sync)
+		status = task->tk_status;
 	trace_nfs4_layoutcommit(data->args.inode, status);
-out:
 	dprintk("%s: status %d\n", __func__, status);
 	rpc_put_task(task);
 	return status;

include/linux/nfs_xdr.h

@@ -285,6 +285,7 @@ struct nfs4_layoutcommit_data {
 	struct nfs_fattr fattr;
 	struct list_head lseg_list;
 	struct rpc_cred *cred;
+	struct inode *inode;
 	struct nfs4_layoutcommit_args args;
 	struct nfs4_layoutcommit_res res;
 };