flexnbd: add a mirror-speed command to change mirror->max_bytes_per_second

It's not actually honoured yet, and ideally, you'd also be able to set it as
part of the initial setup: "flexnbd mirror ... -m 4G". remote_argv for the
mirror case would need to become x=y z=w format first, though.

src/control.c

@@ -310,7 +310,6 @@ enum mirror_state control_client_mirror_wait(
 	return mirror_state;
 }
 
-
 #define write_socket(msg) write(client->socket, (msg "\n"), strlen((msg))+1)
 /** Command parser to start mirror process from socket input */
 int control_mirror(struct control_client* client, int linesc, char** lines)
@@ -437,8 +436,41 @@ int control_mirror(struct control_client* client, int linesc, char** lines)
 	return 0;
 }
 
-#undef write_socket
+int control_mirror_max_bps( struct control_client* client, int linesc, char** lines )
+{
+	NULLCHECK( client );
+	NULLCHECK( client->flexnbd );
 
+	struct server* serve = flexnbd_server( client->flexnbd );
+	uint64_t max_Bps;
+
+	if ( !serve->mirror_super ) {
+		write_socket( "1: Not currently mirroring" );
+		return -1;
+	}
+
+	if ( linesc != 1 ) {
+		write_socket( "1: Bad format" );
+		return -1;
+	}
+
+	errno = 0;
+	max_Bps = strtoull( lines[0], NULL, 10 );
+	if ( errno == ERANGE ) {
+		write_socket( "1: max_bps out of range" );
+		return -1;
+	} else if ( errno != 0 ) {
+		write_socket( "1: max_bps couldn't be parsed" );
+		return -1;
+	}
+
+	serve->mirror->max_bytes_per_second = max_Bps;
+	write_socket( "0: updated" );
+
+	return 0;
+}
+
+#undef write_socket
 
 /** Command parser to alter access control list from socket input */
 int control_acl(struct control_client* client, int linesc, char** lines)
@@ -581,6 +613,11 @@ void control_respond(struct control_client * client)
 		if (control_status(client, linesc-1, lines+1) < 0) {
 			debug("status command failed");
 		}
+	} else if ( strcmp( lines[0], "mirror_max_bps" ) == 0 ) {
+		info( "mirror_max_bps command received" );
+		if( control_mirror_max_bps( client, linesc-1, lines+1 ) < 0 ) {
+			debug( "mirror_max_bps command failed" );
+		}
 	}
 	else {
 		write(client->socket, "10: unknown command\n", 23);

src/mode.c

@@ -113,6 +113,24 @@ static char acl_help_text[] =
 	VERBOSE_LINE
 	QUIET_LINE;
 
+static struct option mirror_speed_options[] = {
+	GETOPT_HELP,
+	GETOPT_SOCK,
+	GETOPT_MAX_SPEED,
+	GETOPT_QUIET,
+	GETOPT_VERBOSE,
+	{0}
+};
+static char mirror_speed_short_options[] = "hs:m:" SOPT_QUIET SOPT_VERBOSE;
+static char mirror_speed_help_text[] =
+	"Usage: flexnbd " CMD_MIRROR_SPEED " <options>\n\n"
+	"Set the maximum speed of a migration from a mirring server listening on SOCK.\n\n"
+	HELP_LINE
+	SOCK_LINE
+	MAX_SPEED_LINE
+	VERBOSE_LINE
+	QUIET_LINE;
+
 static struct option mirror_options[] = {
 	GETOPT_HELP,
 	GETOPT_SOCK,
@@ -179,6 +197,7 @@ char help_help_text_arr[] =
 	"\tflexnbd write\n"
 	"\tflexnbd acl\n"
 	"\tflexnbd mirror\n"
+	"\tflexnbd mirror-speed\n"
 	"\tflexnbd break\n"
 	"\tflexnbd status\n"
 	"\tflexnbd help\n\n"
@@ -333,6 +352,36 @@ void read_acl_param( int c, char **sock )
 	read_sock_param( c, sock, acl_help_text );
 }
 
+void read_mirror_speed_param(
+		int c,
+		char **sock,
+		char **max_speed
+)
+{
+	switch( c ) {
+		case 'h':
+			fprintf( stdout, "%s\n", mirror_speed_help_text );
+			exit( 0 );
+			break;
+		case 's':
+			*sock = optarg;
+			break;
+		case 'm':
+			*max_speed = optarg;
+			break;
+		case 'q':
+			log_level = QUIET_LOG_LEVEL;
+			break;
+		case 'v':
+			log_level = VERBOSE_LOG_LEVEL;
+			break;
+		default:
+			exit_err( mirror_speed_help_text );
+			break;
+
+	}
+}
+
 void read_mirror_param(
 		int c,
 		char **sock,
@@ -655,6 +704,33 @@ int mode_acl( int argc, char *argv[] )
 }
 
 
+int mode_mirror_speed( int argc, char *argv[] )
+{
+	int c;
+	char *sock = NULL;
+	char *speed = NULL;
+
+	while( 1 ) {
+		c = getopt_long( argc, argv, mirror_speed_short_options, mirror_speed_options, NULL );
+		if ( -1 == c ) { break; }
+		read_mirror_speed_param( c, &sock, &speed );
+	}
+
+	if ( NULL == sock ) {
+		fprintf( stderr, "--sock is required.\n" );
+		exit_err( mirror_speed_help_text );
+	}
+
+	if ( NULL == speed ) {
+		fprintf( stderr, "--max-speed is required.\n");
+		exit_err( mirror_speed_help_text );
+	}
+
+	do_remote_command( "mirror_max_bps", sock, 1, &speed );
+	return 0;
+}
+
+
 int mode_mirror( int argc, char *argv[] )
 {
 	int c;
@@ -787,6 +863,8 @@ void mode(char* mode, int argc, char **argv)
 	}
 	else if ( IS_CMD( CMD_ACL, mode ) ) {
 		mode_acl( argc, argv );
+	} else if ( IS_CMD ( CMD_MIRROR_SPEED, mode ) ) {
+		mode_mirror_speed( argc, argv );
 	}
 	else if ( IS_CMD( CMD_MIRROR, mode ) ) {
 		mode_mirror( argc, argv );

src/mode.h

@@ -23,6 +23,7 @@ void mode(char* mode, int argc, char **argv);
 #define OPT_CONNECT_ADDR "conn-addr"
 #define OPT_CONNECT_PORT "conn-port"
 #define OPT_KILLSWITCH "killswitch"
+#define OPT_MAX_SPEED "max-speed"
 
 #define CMD_SERVE  "serve"
 #define CMD_LISTEN "listen"
@@ -30,10 +31,11 @@ void mode(char* mode, int argc, char **argv);
 #define CMD_WRITE  "write"
 #define CMD_ACL    "acl"
 #define CMD_MIRROR "mirror"
+#define CMD_MIRROR_SPEED "mirror-speed"
 #define CMD_BREAK  "break"
 #define CMD_STATUS "status"
 #define CMD_HELP   "help"
-#define LEN_CMD_MAX 7
+#define LEN_CMD_MAX 13
 
 #define PATH_LEN_MAX 1024
 #define ADDR_LEN_MAX 64
@@ -54,6 +56,7 @@ void mode(char* mode, int argc, char **argv);
 #define GETOPT_CONNECT_ADDR GETOPT_ARG( OPT_CONNECT_ADDR, 'C' )
 #define GETOPT_CONNECT_PORT GETOPT_ARG( OPT_CONNECT_PORT, 'P' )
 #define GETOPT_KILLSWITCH   GETOPT_ARG( OPT_KILLSWITCH,   'k' )
+#define GETOPT_MAX_SPEED    GETOPT_ARG( OPT_MAX_SPEED, 'm' )
 
 #define OPT_VERBOSE "verbose"
 #define SOPT_VERBOSE "v"
@@ -82,7 +85,8 @@ void mode(char* mode, int argc, char **argv);
 	"\t--" OPT_SOCK  ",-s <SOCK>\tPath to the control socket.\n"
 #define BIND_LINE \
 	 "\t--" OPT_BIND ",-b <BIND-ADDR>\tBind the local socket to a particular IP address.\n"
-
+#define MAX_SPEED_LINE \
+	 "\t--" OPT_MAX_SPEED ",-m <bps>\tMaximum speed of the migration, in bytes/sec.\n"
 
 char * help_help_text;
 

src/remote.c

@@ -17,7 +17,7 @@ void print_response( const char * response )
 	exit_status = atoi(response);
 	response_text = strchr( response, ':' );
 
-	FATAL_IF_NULL( response_text, 
+	FATAL_IF_NULL( response_text,
 			"Error parsing server response: '%s'", response );
 
 	out = exit_status > 0 ? stderr : stdout;
@@ -32,19 +32,19 @@ void do_remote_command(char* command, char* socket_name, int argc, char** argv)
 	int remote = socket(AF_UNIX, SOCK_STREAM, 0);
 	struct sockaddr_un address;
 	char response[max_response];
-	
+
 	memset(&address, 0, sizeof(address));
-	
+
 	FATAL_IF_NEGATIVE(remote, "Couldn't create client socket");
-	
+
 	address.sun_family = AF_UNIX;
 	strncpy(address.sun_path, socket_name, sizeof(address.sun_path));
-	
+
 	FATAL_IF_NEGATIVE(
 		connect(remote, (struct sockaddr*) &address, sizeof(address)),
 		"Couldn't connect to %s", socket_name
 	);
-	
+
 	write(remote, command, strlen(command));
 	write(remote, &newline, 1);
 	for (i=0; i<argc; i++) {
@@ -54,16 +54,16 @@ void do_remote_command(char* command, char* socket_name, int argc, char** argv)
 		write(remote, &newline, 1);
 	}
 	write(remote, &newline, 1);
-	
+
 	FATAL_IF_NEGATIVE(
 		read_until_newline(remote, response, max_response),
 		"Couldn't read response from %s", socket_name
 	);
-	
+
 	print_response( response );
 
 	exit(atoi(response));
-	
+
 	close(remote);
 }