replication: ballot.is_ro -> is_ro_cfg

Rename the member to show its actual meaning. It is not the
real RO state of the instance. Only how it is configured.

It can happen that the instance is read_only = false, but still is
in RO state due to other reasons.

The patch is done in scope of #5613 where the ballot is going to
be extended and used a bit differently in the join-master search
algorithm.

Part of #5613

src/box/box.cc

@@ -2860,7 +2860,7 @@ box_process_subscribe(struct ev_io *io, struct xrow_header *header)
 void
 box_process_vote(struct ballot *ballot)
 {
-	ballot->is_ro = cfg_geti("read_only") != 0;
+	ballot->is_ro_cfg = cfg_geti("read_only") != 0;
 	ballot->is_anon = replication_anon;
 	/*
 	 * is_ro is true on initial load and is set to box.cfg.read_only

src/box/iproto_constants.h

@@ -162,7 +162,7 @@ enum iproto_metadata_key {
 };
 
 enum iproto_ballot_key {
-	IPROTO_BALLOT_IS_RO = 0x01,
+	IPROTO_BALLOT_IS_RO_CFG = 0x01,
 	IPROTO_BALLOT_VCLOCK = 0x02,
 	IPROTO_BALLOT_GC_VCLOCK = 0x03,
 	IPROTO_BALLOT_IS_LOADING = 0x04,

src/box/replication.cc

@@ -976,7 +976,7 @@ replicaset_round(bool skip_ro)
 		 * replicas since there is still a possibility
 		 * that all replicas exist in cluster table.
 		 */
-		if (skip_ro && ballot->is_ro)
+		if (skip_ro && ballot->is_ro_cfg)
 			continue;
 		if (leader == NULL) {
 			leader = replica;

src/box/xrow.c

@@ -450,7 +450,7 @@ iproto_reply_vote(struct obuf *out, const struct ballot *ballot,
 {
 	size_t max_size = IPROTO_HEADER_LEN + mp_sizeof_map(1) +
 		mp_sizeof_uint(UINT32_MAX) + mp_sizeof_map(5) +
-		mp_sizeof_uint(UINT32_MAX) + mp_sizeof_bool(ballot->is_ro) +
+		mp_sizeof_uint(UINT32_MAX) + mp_sizeof_bool(ballot->is_ro_cfg) +
 		mp_sizeof_uint(UINT32_MAX) + mp_sizeof_bool(ballot->is_loading) +
 		mp_sizeof_uint(IPROTO_BALLOT_IS_ANON) +
 		mp_sizeof_bool(ballot->is_anon) +
@@ -470,8 +470,8 @@ iproto_reply_vote(struct obuf *out, const struct ballot *ballot,
 	data = mp_encode_map(data, 1);
 	data = mp_encode_uint(data, IPROTO_BALLOT);
 	data = mp_encode_map(data, 5);
-	data = mp_encode_uint(data, IPROTO_BALLOT_IS_RO);
-	data = mp_encode_bool(data, ballot->is_ro);
+	data = mp_encode_uint(data, IPROTO_BALLOT_IS_RO_CFG);
+	data = mp_encode_bool(data, ballot->is_ro_cfg);
 	data = mp_encode_uint(data, IPROTO_BALLOT_IS_LOADING);
 	data = mp_encode_bool(data, ballot->is_loading);
 	data = mp_encode_uint(data, IPROTO_BALLOT_IS_ANON);
@@ -1357,7 +1357,7 @@ xrow_encode_vote(struct xrow_header *row)
 int
 xrow_decode_ballot(struct xrow_header *row, struct ballot *ballot)
 {
-	ballot->is_ro = false;
+	ballot->is_ro_cfg = false;
 	ballot->is_loading = false;
 	ballot->is_anon = false;
 	vclock_create(&ballot->vclock);
@@ -1399,10 +1399,10 @@ xrow_decode_ballot(struct xrow_header *row, struct ballot *ballot)
 		}
 		uint32_t key = mp_decode_uint(&data);
 		switch (key) {
-		case IPROTO_BALLOT_IS_RO:
+		case IPROTO_BALLOT_IS_RO_CFG:
 			if (mp_typeof(*data) != MP_BOOL)
 				goto err;
-			ballot->is_ro = mp_decode_bool(&data);
+			ballot->is_ro_cfg = mp_decode_bool(&data);
 			break;
 		case IPROTO_BALLOT_IS_LOADING:
 			if (mp_typeof(*data) != MP_BOOL)

src/box/xrow.h

@@ -366,8 +366,8 @@ xrow_encode_auth(struct xrow_header *row, const char *salt, size_t salt_len,
 
 /** Reply to IPROTO_VOTE request. */
 struct ballot {
-	/** Set if the instance is running in read-only mode. */
-	bool is_ro;
+	/** Set if the instance is configured in read-only mode. */
+	bool is_ro_cfg;
 	/**
 	 * A flag whether the instance is anonymous, not having an
 	 * ID, and not going to request it.