Fix failure to save RDB on shutdown

Former-commit-id: 1a8331c88a17deaa5faf34c7ea65957c57530546

src/db.cpp

@@ -2301,6 +2301,9 @@ void redisDbPersistentData::commitChanges(const changelist &vec)
 
 redisDbPersistentData::~redisDbPersistentData()
 {
+    if (m_pdbSnapshotASYNC)
+        endSnapshot(m_pdbSnapshotASYNC);
+    
     serverAssert(m_spdbSnapshotHOLDER == nullptr);
     //serverAssert(m_pdbSnapshot == nullptr);
     serverAssert(m_refCount == 0);

src/rdb.cpp

@@ -2644,14 +2644,23 @@ void backgroundSaveDoneHandler(int exitcode, bool fCancelled) {
 }
 
 /* Kill the RDB saving child using SIGUSR1 (so that the parent will know
- * the child did not exit for an error, but because we wanted), and performs
+ * the child did not exit for sn error, but because we wanted), and performs
  * the cleanup needed. */
-void killRDBChild(void) {
+void killRDBChild(bool fSynchronous) {
     serverAssert(GlobalLocksAcquired());
     g_pserver->rdbThreadVars.fRdbThreadCancel = true;
     rdbRemoveTempFile(g_pserver->rdbThreadVars.tmpfileNum);
     closeChildInfoPipe();
     updateDictResizePolicy();
+    if (fSynchronous)
+    {
+        aeReleaseLock();
+        serverAssert(!GlobalLocksAcquired());
+        void *result;
+        pthread_join(g_pserver->rdbThreadVars.rdb_child_thread, &result);
+        g_pserver->rdbThreadVars.fRdbThreadCancel = false;
+        aeAcquireLock();
+    }
 }
 
 struct rdbSaveSocketThreadArgs

src/server.cpp

@@ -3960,7 +3960,7 @@ int prepareForShutdown(int flags) {
        overwrite the synchronous saving did by SHUTDOWN. */
     if (g_pserver->FRdbSaveInProgress()) {
         serverLog(LL_WARNING,"There is a child saving an .rdb. Killing it!");
-        killRDBChild();
+        killRDBChild(true);
     }
 
     /* Kill module child if there is one. */

src/server.h

@@ -2767,7 +2767,7 @@ int writeCommandsDeniedByDiskError(void);
 
 /* RDB persistence */
 #include "rdb.h"
-void killRDBChild(void);
+void killRDBChild(bool fSynchronous = false);
 
 /* AOF persistence */
 void flushAppendOnlyFile(int force);