From bd7908e6ace1edce3530a0aa663ec3527e53c8e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <marko.makela@mariadb.com>
Date: Wed, 5 Jul 2023 15:15:04 +0300
Subject: [PATCH] MDEV-31568 InnoDB protection against dual processes accessing
 data insufficient

fil_node_open_file_low(): Always acquire an advisory lock on
the system tablespace. Originally, we already did this in
SysTablespace::open_file(), but SysTablespace::open_or_create()
would release those locks when it is closing the file handles.

This is a 10.5+ specific follow up to
commit 0ee1082bd2e7e7049c4f0e686bad53cf7ba053ab (MDEV-28495).

Thanks to Daniel Black for verifying this bug.
---
 storage/innobase/fil/fil0fil.cc | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/storage/innobase/fil/fil0fil.cc b/storage/innobase/fil/fil0fil.cc
index c75144413ac..725345957ee 100644
--- a/storage/innobase/fil/fil0fil.cc
+++ b/storage/innobase/fil/fil0fil.cc
@@ -391,8 +391,16 @@ static bool fil_node_open_file_low(fil_node_t *node)
                                  : OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT,
                                  OS_FILE_AIO, type,
                                  srv_read_only_mode, &success);
-    if (success)
+    if (node->is_open())
+    {
+      ut_ad(success);
+#ifndef _WIN32
+      if (!node->space->id && !srv_read_only_mode && my_disable_locking &&
+          os_file_lock(node->handle, node->name))
+        goto fail;
+#endif
       break;
+    }
 
     /* The following call prints an error message */
     if (os_file_get_last_error(true) == EMFILE + 100 &&
@@ -406,6 +414,9 @@ static bool fil_node_open_file_low(fil_node_t *node)
   if (node->size);
   else if (!node->read_page0() || !fil_comp_algo_validate(node->space))
   {
+#ifndef _WIN32
+  fail:
+#endif
     os_file_close(node->handle);
     node->handle= OS_FILE_CLOSED;
     return false;