Merge bitcoin/bitcoin#24168: Fix some race conditions in BanMan::DumpBanlist()

99a6b69 Fix race condition for SetBannedSetDirty() calls (Hennadii Stepanov)
83c7646 Avoid calling BanMan::SweepBanned() twice in a row (Hennadii Stepanov)
33bda6a Fix data race condition in BanMan::DumpBanlist() (Hennadii Stepanov)
5e20e9e Prevent possible concurrent CBanDB::Write() calls (Hennadii Stepanov)

Pull request description:

  This PR split from bitcoin/bitcoin#24097 with some additions. This makes the following switch from `RecursiveMutex` to `Mutex` a pure refactoring.

  See details in commit messages.

ACKs for top commit:
  w0xlt:
    reACK 99a6b69
  shaavan:
    ACK 99a6b69

Tree-SHA512: da4e7268c7bd3424491f446145f18af4ccfc804023d0a7fe70e1462baab550a5e44f9159f8b9f9c7820d2c6cb6447b63883616199e4d9d439ab9ab1b67c7201b

Author: MarcoFalke

src/banman.cpp

@@ -7,6 +7,7 @@
 
 #include <netaddress.h>
 #include <node/ui_interface.h>
+#include <sync.h>
 #include <util/system.h>
 #include <util/time.h>
 #include <util/translation.h>
@@ -39,18 +40,23 @@ BanMan::~BanMan()
 
 void BanMan::DumpBanlist()
 {
-    SweepBanned(); // clean unused entries (if bantime has expired)
-
-    if (!BannedSetIsDirty()) return;
-
-    int64_t n_start = GetTimeMillis();
+    static Mutex dump_mutex;
+    LOCK(dump_mutex);
 
     banmap_t banmap;
-    GetBanned(banmap);
-    if (m_ban_db.Write(banmap)) {
+    {
+        LOCK(m_cs_banned);
+        SweepBanned();
+        if (!BannedSetIsDirty()) return;
+        banmap = m_banned;
         SetBannedSetDirty(false);
     }
 
+    int64_t n_start = GetTimeMillis();
+    if (!m_ban_db.Write(banmap)) {
+        SetBannedSetDirty(true);
+    }
+
     LogPrint(BCLog::NET, "Flushed %d banned node addresses/subnets to disk  %dms\n", banmap.size(),
              GetTimeMillis() - n_start);
 }