MDEV-6368: assertion xid_seqno > trx_sys_cur_xid_seqno

- Validate the specified wsrep_start_position value by also
checking the return status of wsrep->sst_received. This also
ensures that changes in wsrep_start_position is not allowed
when the node is not in JOINING state.
- Do not allow decrease in seqno within same UUID.
- The initial checkpoint in SEs should be [0...:-1].

1 files changed, 20 insertions, 10 deletions

diff --git a/sql/wsrep_xid.cc b/sql/wsrep_xid.cc
index 133e9cba825..876f791da69 100644
--- a/sql/wsrep_xid.cc
+++ b/sql/wsrep_xid.cc
@@ -89,16 +89,17 @@ static my_bool set_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
   return FALSE;
 }
 
-void wsrep_set_SE_checkpoint(XID& xid)
+bool wsrep_set_SE_checkpoint(XID& xid)
 {
-  plugin_foreach(NULL, set_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, &xid);
+  return plugin_foreach(NULL, set_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN,
+                        &xid);
 }
 
-void wsrep_set_SE_checkpoint(const wsrep_uuid_t& uuid, wsrep_seqno_t seqno)
+bool wsrep_set_SE_checkpoint(const wsrep_uuid_t& uuid, wsrep_seqno_t seqno)
 {
   XID xid;
   wsrep_xid_init(&xid, uuid, seqno);
-  wsrep_set_SE_checkpoint(xid);
+  return wsrep_set_SE_checkpoint(xid);
 }
 
 static my_bool get_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
@@ -118,12 +119,13 @@ static my_bool get_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
   return FALSE;
 }
 
-void wsrep_get_SE_checkpoint(XID& xid)
+bool wsrep_get_SE_checkpoint(XID& xid)
 {
-  plugin_foreach(NULL, get_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, &xid);
+  return plugin_foreach(NULL, get_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN,
+                        &xid);
 }
 
-void wsrep_get_SE_checkpoint(wsrep_uuid_t& uuid, wsrep_seqno_t& seqno)
+bool wsrep_get_SE_checkpoint(wsrep_uuid_t& uuid, wsrep_seqno_t& seqno)
 {
   uuid= WSREP_UUID_UNDEFINED;
   seqno= WSREP_SEQNO_UNDEFINED;
@@ -132,16 +134,24 @@ void wsrep_get_SE_checkpoint(wsrep_uuid_t& uuid, wsrep_seqno_t& seqno)
   memset(&xid, 0, sizeof(xid));
   xid.formatID= -1;
 
-  wsrep_get_SE_checkpoint(xid);
+  if (wsrep_get_SE_checkpoint(xid))
+  {
+    return true;
+  }
 
-  if (xid.formatID == -1) return; // nil XID
+  if (xid.formatID == -1)                       // nil XID
+  {
+    return false;
+  }
 
   if (!wsrep_is_wsrep_xid(&xid))
   {
     WSREP_WARN("Read non-wsrep XID from storage engines.");
-    return;
+    return false;
   }
 
   uuid= *wsrep_xid_uuid(xid);
   seqno= wsrep_xid_seqno(xid);
+
+  return false;
 }