From 54e62ad43c0432a610b102eb82842176b482d18c Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Wed, 20 Jan 2016 11:22:22 -0700
Subject: [PATCH] client: drain text output when exiting

If we don't, we can lose error messages from the server side. One
example would be for protocol version mismatch - the server will
notify the client, but the client doesn't check for these messages
before exiting.

Signed-off-by: Jens Axboe <axboe@fb.com>
---
 client.c | 25 ++++++++++++++++++++++++-
 server.c | 27 ++++++++++++++++++---------
 server.h |  2 +-
 3 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/client.c b/client.c
index 6c2a1ef3..c61301de 100644
--- a/client.c
+++ b/client.c
@@ -33,6 +33,8 @@ static void handle_text(struct fio_client *client, struct fio_net_cmd *cmd);
 static void handle_stop(struct fio_client *client, struct fio_net_cmd *cmd);
 static void handle_start(struct fio_client *client, struct fio_net_cmd *cmd);
 
+static void convert_text(struct fio_net_cmd *cmd);
+
 struct client_ops fio_client_ops = {
 	.text		= handle_text,
 	.disk_util	= handle_du,
@@ -215,12 +217,33 @@ static int fio_client_dec_jobs_eta(struct client_eta *eta, client_eta_op eta_fn)
 	return 1;
 }
 
+static void fio_drain_client_text(struct fio_client *client)
+{
+	do {
+		struct fio_net_cmd *cmd;
+
+		cmd = fio_net_recv_cmd(client->fd, false);
+		if (!cmd)
+			break;
+
+		if (cmd->opcode != FIO_NET_CMD_TEXT) {
+			free(cmd);
+			continue;
+		}
+
+		convert_text(cmd);
+		client->ops->text(client, cmd);
+	} while (1);
+}
+
 static void remove_client(struct fio_client *client)
 {
 	assert(client->refs);
 
 	dprint(FD_NET, "client: removed <%s>\n", client->hostname);
 
+	fio_drain_client_text(client);
+
 	if (!flist_empty(&client->list))
 		flist_del_init(&client->list);
 
@@ -1526,7 +1549,7 @@ int fio_handle_client(struct fio_client *client)
 
 	dprint(FD_NET, "client: handle %s\n", client->hostname);
 
-	cmd = fio_net_recv_cmd(client->fd);
+	cmd = fio_net_recv_cmd(client->fd, true);
 	if (!cmd)
 		return 0;
 
diff --git a/server.c b/server.c
index a593a73f..f6f34418 100644
--- a/server.c
+++ b/server.c
@@ -262,10 +262,17 @@ static int fio_send_data(int sk, const void *p, unsigned int len)
 	return fio_sendv_data(sk, &iov, 1);
 }
 
-static int fio_recv_data(int sk, void *p, unsigned int len)
+static int fio_recv_data(int sk, void *p, unsigned int len, bool wait)
 {
+	int flags;
+
+	if (wait)
+		flags = MSG_WAITALL;
+	else
+		flags = MSG_DONTWAIT;
+
 	do {
-		int ret = recv(sk, p, len, MSG_WAITALL);
+		int ret = recv(sk, p, len, flags);
 
 		if (ret > 0) {
 			len -= ret;
@@ -275,9 +282,11 @@ static int fio_recv_data(int sk, void *p, unsigned int len)
 			continue;
 		} else if (!ret)
 			break;
-		else if (errno == EAGAIN || errno == EINTR)
-			continue;
-		else
+		else if (errno == EAGAIN || errno == EINTR) {
+			if (wait)
+				continue;
+			break;
+		} else
 			break;
 	} while (!exit_backend);
 
@@ -326,7 +335,7 @@ static int verify_convert_cmd(struct fio_net_cmd *cmd)
 /*
  * Read (and defragment, if necessary) incoming commands
  */
-struct fio_net_cmd *fio_net_recv_cmd(int sk)
+struct fio_net_cmd *fio_net_recv_cmd(int sk, bool wait)
 {
 	struct fio_net_cmd cmd, *tmp, *cmdret = NULL;
 	size_t cmd_size = 0, pdu_offset = 0;
@@ -335,7 +344,7 @@ struct fio_net_cmd *fio_net_recv_cmd(int sk)
 	void *pdu = NULL;
 
 	do {
-		ret = fio_recv_data(sk, &cmd, sizeof(cmd));
+		ret = fio_recv_data(sk, &cmd, sizeof(cmd), wait);
 		if (ret)
 			break;
 
@@ -379,7 +388,7 @@ struct fio_net_cmd *fio_net_recv_cmd(int sk)
 
 		/* There's payload, get it */
 		pdu = (void *) cmdret->payload + pdu_offset;
-		ret = fio_recv_data(sk, pdu, cmd.pdu_len);
+		ret = fio_recv_data(sk, pdu, cmd.pdu_len, wait);
 		if (ret)
 			break;
 
@@ -1209,7 +1218,7 @@ static int handle_connection(struct sk_out *sk_out)
 		if (ret < 0)
 			break;
 
-		cmd = fio_net_recv_cmd(sk_out->sk);
+		cmd = fio_net_recv_cmd(sk_out->sk, true);
 		if (!cmd) {
 			ret = -1;
 			break;
diff --git a/server.h b/server.h
index 12c72759..05f98e56 100644
--- a/server.h
+++ b/server.h
@@ -213,7 +213,7 @@ extern void fio_server_send_du(void);
 extern void fio_server_send_job_options(struct flist_head *, unsigned int);
 extern int fio_server_get_verify_state(const char *, int, void **, int *);
 
-extern struct fio_net_cmd *fio_net_recv_cmd(int sk);
+extern struct fio_net_cmd *fio_net_recv_cmd(int sk, bool wait);
 
 extern int fio_send_iolog(struct thread_data *, struct io_log *, const char *);
 extern void fio_server_send_add_job(struct thread_data *);
-- 
2.25.1