Update rdb_last_bgsave_time_sec in INFO on diskless replication (redi…

…s#7917)

`info Persistence` will include correct (updated) rdb_last_bgsave_time_sec
For diskless bgsave (sockets) too (like a few other persistence info fields).

Refactor code to reduce duplicate code.

src/rdb.c

@@ -2425,7 +2425,7 @@ int rdbLoad(char *filename, rdbSaveInfo *rsi, int rdbflags) {
 
 /* A background saving child (BGSAVE) terminated its work. Handle this.
  * This function covers the case of actual BGSAVEs. */
-void backgroundSaveDoneHandlerDisk(int exitcode, int bysignal) {
+static void backgroundSaveDoneHandlerDisk(int exitcode, int bysignal) {
     if (!bysignal && exitcode == 0) {
         serverLog(LL_NOTICE,
             "Background saving terminated with success");
@@ -2449,19 +2449,12 @@ void backgroundSaveDoneHandlerDisk(int exitcode, int bysignal) {
         if (bysignal != SIGUSR1)
             server.lastbgsave_status = C_ERR;
     }
-    server.rdb_child_pid = -1;
-    server.rdb_child_type = RDB_CHILD_TYPE_NONE;
-    server.rdb_save_time_last = time(NULL)-server.rdb_save_time_start;
-    server.rdb_save_time_start = -1;
-    /* Possibly there are slaves waiting for a BGSAVE in order to be served
-     * (the first stage of SYNC is a bulk transfer of dump.rdb) */
-    updateSlavesWaitingBgsave((!bysignal && exitcode == 0) ? C_OK : C_ERR, RDB_CHILD_TYPE_DISK);
 }
 
 /* A background saving child (BGSAVE) terminated its work. Handle this.
  * This function covers the case of RDB -> Slaves socket transfers for
  * diskless replication. */
-void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
+static void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
     if (!bysignal && exitcode == 0) {
         serverLog(LL_NOTICE,
             "Background RDB transfer terminated with success");
@@ -2471,9 +2464,6 @@ void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
         serverLog(LL_WARNING,
             "Background transfer terminated by signal %d", bysignal);
     }
-    server.rdb_child_pid = -1;
-    server.rdb_child_type = RDB_CHILD_TYPE_NONE;
-    server.rdb_save_time_start = -1;
     if (server.rdb_child_exit_pipe!=-1)
         close(server.rdb_child_exit_pipe);
     close(server.rdb_pipe_read);
@@ -2486,12 +2476,11 @@ void backgroundSaveDoneHandlerSocket(int exitcode, int bysignal) {
     zfree(server.rdb_pipe_buff);
     server.rdb_pipe_buff = NULL;
     server.rdb_pipe_bufflen = 0;
-
-    updateSlavesWaitingBgsave((!bysignal && exitcode == 0) ? C_OK : C_ERR, RDB_CHILD_TYPE_SOCKET);
 }
 
 /* When a background RDB saving/transfer terminates, call the right handler. */
 void backgroundSaveDoneHandler(int exitcode, int bysignal) {
+    int type = server.rdb_child_type;
     switch(server.rdb_child_type) {
     case RDB_CHILD_TYPE_DISK:
         backgroundSaveDoneHandlerDisk(exitcode,bysignal);
@@ -2503,6 +2492,14 @@ void backgroundSaveDoneHandler(int exitcode, int bysignal) {
         serverPanic("Unknown RDB child type.");
         break;
     }
+
+    server.rdb_child_pid = -1;
+    server.rdb_child_type = RDB_CHILD_TYPE_NONE;
+    server.rdb_save_time_last = time(NULL)-server.rdb_save_time_start;
+    server.rdb_save_time_start = -1;
+    /* Possibly there are slaves waiting for a BGSAVE in order to be served
+     * (the first stage of SYNC is a bulk transfer of dump.rdb) */
+    updateSlavesWaitingBgsave((!bysignal && exitcode == 0) ? C_OK : C_ERR, type);
 }
 
 /* Kill the RDB saving child using SIGUSR1 (so that the parent will know