ceph: separate banner and connect during handshake into distinct stages

We need to make sure we only swab the address during the banner once.  So
break process_banner out of process_connect, and clean up the surrounding
code so that these are distinct phases of the handshake.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/messenger.c

@@ -564,10 +564,26 @@ static void prepare_write_keepalive(struct ceph_connection *con)
 /*
  * We connected to a peer and are saying hello.
  */
-static void prepare_write_connect(struct ceph_messenger *msgr,
+static void prepare_write_banner(struct ceph_messenger *msgr,
 				 struct ceph_connection *con)
 {
 	int len = strlen(CEPH_BANNER);
+
+	con->out_kvec[0].iov_base = CEPH_BANNER;
+	con->out_kvec[0].iov_len = len;
+	con->out_kvec[1].iov_base = &msgr->my_enc_addr;
+	con->out_kvec[1].iov_len = sizeof(msgr->my_enc_addr);
+	con->out_kvec_left = 2;
+	con->out_kvec_bytes = len + sizeof(msgr->my_enc_addr);
+	con->out_kvec_cur = con->out_kvec;
+	con->out_more = 0;
+	set_bit(WRITE_PENDING, &con->state);
+}
+
+static void prepare_write_connect(struct ceph_messenger *msgr,
+				  struct ceph_connection *con,
+				  int after_banner)
+{
 	unsigned global_seq = get_global_seq(con->msgr, 0);
 	int proto;
 
@@ -595,32 +611,14 @@ static void prepare_write_connect(struct ceph_messenger *msgr,
 	if (test_bit(LOSSYTX, &con->state))
 		con->out_connect.flags = CEPH_MSG_CONNECT_LOSSY;
 
-	con->out_kvec[0].iov_base = CEPH_BANNER;
-	con->out_kvec[0].iov_len = len;
-	con->out_kvec[1].iov_base = &msgr->my_enc_addr;
-	con->out_kvec[1].iov_len = sizeof(msgr->my_enc_addr);
-	con->out_kvec[2].iov_base = &con->out_connect;
-	con->out_kvec[2].iov_len = sizeof(con->out_connect);
-	con->out_kvec_left = 3;
-	con->out_kvec_bytes = len + sizeof(msgr->my_enc_addr) +
-		sizeof(con->out_connect);
-	con->out_kvec_cur = con->out_kvec;
-	con->out_more = 0;
-	set_bit(WRITE_PENDING, &con->state);
-}
-
-static void prepare_write_connect_retry(struct ceph_messenger *msgr,
-					struct ceph_connection *con)
-{
-	dout("prepare_write_connect_retry %p\n", con);
-	con->out_connect.connect_seq = cpu_to_le32(con->connect_seq);
-	con->out_connect.global_seq =
-		cpu_to_le32(get_global_seq(con->msgr, 0));
-
-	con->out_kvec[0].iov_base = &con->out_connect;
-	con->out_kvec[0].iov_len = sizeof(con->out_connect);
-	con->out_kvec_left = 1;
-	con->out_kvec_bytes = sizeof(con->out_connect);
+	if (!after_banner) {
+		con->out_kvec_left = 0;
+		con->out_kvec_bytes = 0;
+	}
+	con->out_kvec[con->out_kvec_left].iov_base = &con->out_connect;
+	con->out_kvec[con->out_kvec_left].iov_len = sizeof(con->out_connect);
+	con->out_kvec_left++;
+	con->out_kvec_bytes += sizeof(con->out_connect);
 	con->out_kvec_cur = con->out_kvec;
 	con->out_more = 0;
 	set_bit(WRITE_PENDING, &con->state);
@@ -778,6 +776,12 @@ static int write_partial_skip(struct ceph_connection *con)
 /*
  * Prepare to read connection handshake, or an ack.
  */
+static void prepare_read_banner(struct ceph_connection *con)
+{
+	dout("prepare_read_banner %p\n", con);
+	con->in_base_pos = 0;
+}
+
 static void prepare_read_connect(struct ceph_connection *con)
 {
 	dout("prepare_read_connect %p\n", con);
@@ -829,11 +833,11 @@ static int read_partial(struct ceph_connection *con,
 /*
  * Read all or part of the connect-side handshake on a new connection
  */
-static int read_partial_connect(struct ceph_connection *con)
+static int read_partial_banner(struct ceph_connection *con)
 {
 	int ret, to = 0;
 
-	dout("read_partial_connect %p at %d\n", con, con->in_base_pos);
+	dout("read_partial_banner %p at %d\n", con, con->in_base_pos);
 
 	/* peer's banner */
 	ret = read_partial(con, &to, strlen(CEPH_BANNER), con->in_banner);
@@ -847,6 +851,16 @@ static int read_partial_connect(struct ceph_connection *con)
 			   &con->peer_addr_for_me);
 	if (ret <= 0)
 		goto out;
+out:
+	return ret;
+}
+
+static int read_partial_connect(struct ceph_connection *con)
+{
+	int ret, to = 0;
+
+	dout("read_partial_connect %p at %d\n", con, con->in_base_pos);
+
 	ret = read_partial(con, &to, sizeof(con->in_reply), &con->in_reply);
 	if (ret <= 0)
 		goto out;
@@ -856,6 +870,7 @@ static int read_partial_connect(struct ceph_connection *con)
 	     le32_to_cpu(con->in_reply.global_seq));
 out:
 	return ret;
+
 }
 
 /*
@@ -976,9 +991,9 @@ int ceph_parse_ips(const char *c, const char *end,
 	return -EINVAL;
 }
 
-static int process_connect(struct ceph_connection *con)
+static int process_banner(struct ceph_connection *con)
 {
-	dout("process_connect on %p tag %d\n", con, (int)con->in_tag);
+	dout("process_banner on %p\n", con);
 
 	if (verify_hello(con) < 0)
 		return -1;
@@ -1016,10 +1031,19 @@ static int process_connect(struct ceph_connection *con)
 		       sizeof(con->peer_addr_for_me.in_addr));
 		addr_set_port(&con->msgr->inst.addr.in_addr, port);
 		encode_my_addr(con->msgr);
-		dout("process_connect learned my addr is %s\n",
+		dout("process_banner learned my addr is %s\n",
 		     pr_addr(&con->msgr->inst.addr.in_addr));
 	}
 
+	set_bit(NEGOTIATING, &con->state);
+	prepare_read_connect(con);
+	return 0;
+}
+
+static int process_connect(struct ceph_connection *con)
+{
+	dout("process_connect on %p tag %d\n", con, (int)con->in_tag);
+
 	switch (con->in_reply.tag) {
 	case CEPH_MSGR_TAG_BADPROTOVER:
 		dout("process_connect got BADPROTOVER my %d != their %d\n",
@@ -1053,7 +1077,7 @@ static int process_connect(struct ceph_connection *con)
 		       ENTITY_NAME(con->peer_name),
 		       pr_addr(&con->peer_addr.in_addr));
 		reset_connection(con);
-		prepare_write_connect_retry(con->msgr, con);
+		prepare_write_connect(con->msgr, con, 0);
 		prepare_read_connect(con);
 
 		/* Tell ceph about it. */
@@ -1071,7 +1095,7 @@ static int process_connect(struct ceph_connection *con)
 		     le32_to_cpu(con->out_connect.connect_seq),
 		     le32_to_cpu(con->in_connect.connect_seq));
 		con->connect_seq = le32_to_cpu(con->in_connect.connect_seq);
-		prepare_write_connect_retry(con->msgr, con);
+		prepare_write_connect(con->msgr, con, 0);
 		prepare_read_connect(con);
 		break;
 
@@ -1080,19 +1104,17 @@ static int process_connect(struct ceph_connection *con)
 		 * If we sent a smaller global_seq than the peer has, try
 		 * again with a larger value.
 		 */
-		dout("process_connect got RETRY_GLOBAL my %u, peer_gseq = %u\n",
+		dout("process_connect got RETRY_GLOBAL my %u peer_gseq %u\n",
 		     con->peer_global_seq,
 		     le32_to_cpu(con->in_connect.global_seq));
 		get_global_seq(con->msgr,
 			       le32_to_cpu(con->in_connect.global_seq));
-		prepare_write_connect_retry(con->msgr, con);
+		prepare_write_connect(con->msgr, con, 0);
 		prepare_read_connect(con);
 		break;
 
 	case CEPH_MSGR_TAG_READY:
 		clear_bit(CONNECTING, &con->state);
-		if (con->in_reply.flags & CEPH_MSG_CONNECT_LOSSY)
-			set_bit(LOSSYRX, &con->state);
 		con->peer_global_seq = le32_to_cpu(con->in_reply.global_seq);
 		con->connect_seq++;
 		dout("process_connect got READY gseq %d cseq %d (%d)\n",
@@ -1420,9 +1442,11 @@ static int try_write(struct ceph_connection *con)
 		if (test_and_clear_bit(STANDBY, &con->state))
 			con->connect_seq++;
 
-		prepare_write_connect(msgr, con);
-		prepare_read_connect(con);
+		prepare_write_banner(msgr, con);
+		prepare_write_connect(msgr, con, 1);
+		prepare_read_banner(con);
 		set_bit(CONNECTING, &con->state);
+		clear_bit(NEGOTIATING, &con->state);
 
 		con->in_tag = CEPH_MSGR_TAG_READY;
 		dout("try_write initiating connect on %p new state %lu\n",
@@ -1521,7 +1545,16 @@ static int try_read(struct ceph_connection *con)
 	dout("try_read tag %d in_base_pos %d\n", (int)con->in_tag,
 	     con->in_base_pos);
 	if (test_bit(CONNECTING, &con->state)) {
+		if (!test_bit(NEGOTIATING, &con->state)) {
 			dout("try_read connecting\n");
+			ret = read_partial_banner(con);
+			if (ret <= 0)
+				goto done;
+			if (process_banner(con) < 0) {
+				ret = -1;
+				goto out;
+			}
+		}
 		ret = read_partial_connect(con);
 		if (ret <= 0)
 			goto done;

fs/ceph/messenger.h

@@ -104,8 +104,8 @@ struct ceph_msg_pos {
  * thread is currently opening, reading or writing data to the socket.
  */
 #define LOSSYTX         0  /* we can close channel or drop messages on errors */
-#define LOSSYRX         1  /* peer may reset/drop messages */
-#define CONNECTING	2
+#define CONNECTING	1
+#define NEGOTIATING	2
 #define KEEPALIVE_PENDING      3
 #define WRITE_PENDING	4  /* we have data ready to send */
 #define QUEUED          5  /* there is work queued on this connection */