MDEV-29982 Improve the InnoDB log overwrite error message

The InnoDB write-ahead log ib_logfile0 is of fixed size,
specified by innodb_log_file_size. If the tail of the log
manages to overwrite the head (latest checkpoint) of the log,
crash recovery will be broken.

Let us clarify the messages about this, including adding
a message on the completion of a log checkpoint that notes
that the dangerous situation is over.

To reproduce the dangerous scenario, we will introduce the
debug injection label ib_log_checkpoint_avoid_hard, which will
avoid log checkpoints even harder than the previous
ib_log_checkpoint_avoid.

log_t::overwrite_warned: The first known dangerous log sequence number.
Set in log_close() and cleared in log_write_checkpoint_info(),
which will output a "Crash recovery was broken" message.

mysql-test/suite/encryption/r/innochecksum,debug.rdiff

+@@ -30,6 +30,9 @@
+ # Space ID mismatch
+ # Restore the original tables
+ # Corrupt FIL_DATA+10 (data)
++# FOUND 1 is expected for both.
++FOUND 1 /InnoDB: Crash recovery is broken due to insufficient innodb_log_file_size; last checkpoint LSN=\d+, current LSN=\d+\. Shutdown is in progress\..*InnoDB: Crash recovery was broken.*/ in mysqld.1.err
++FOUND 1 /InnoDB: Crash recovery was broken/ in mysqld.1.err
+ # Run innochecksum on t2
+ # Run innochecksum on t3
+ # Run innochecksum on t6

mysql-test/suite/encryption/t/innochecksum.test

@@ -9,6 +9,7 @@
 -- source include/have_file_key_management_plugin.inc
 -- source include/innodb_page_size_small.inc
 -- source include/innodb_checksum_algorithm.inc
+-- source include/maybe_debug.inc
 
 if (!$INNOCHECKSUM) {
   --echo Need innochecksum binary
@@ -18,6 +19,10 @@ if (!$INNOCHECKSUM) {
 --disable_query_log
 # This may be triggered on a slow system or one that lacks native AIO.
 call mtr.add_suppression("InnoDB: Trying to delete tablespace.*pending operations");
+if ($have_debug) {
+SET GLOBAL DEBUG_DBUG='+d,ib_log_checkpoint_avoid_hard';
+call mtr.add_suppression("InnoDB: Crash recovery is broken due to insufficient innodb_log_file_size");
+}
 --enable_query_log
 
 let $checksum_algorithm = `SELECT @@innodb_checksum_algorithm`;
@@ -259,6 +264,15 @@ print FILE pack("H*", "c00lcafedeadb017");
 close FILE or die "close";
 EOF
 
+if ($have_debug) {
+--let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err
+--let SEARCH_PATTERN= InnoDB: Crash recovery is broken due to insufficient innodb_log_file_size; last checkpoint LSN=\\d+, current LSN=\\d+\\. Shutdown is in progress\\..*InnoDB: Crash recovery was broken.*
+--echo # FOUND 1 is expected for both.
+--source include/search_pattern_in_file.inc
+--let SEARCH_PATTERN= InnoDB: Crash recovery was broken
+--source include/search_pattern_in_file.inc
+}
+
 -- disable_result_log
 --error 1
 --exec $INNOCHECKSUM $t1_IBD

storage/innobase/buf/buf0flu.cc

@@ -1947,6 +1947,7 @@ ATTRIBUTE_COLD void buf_flush_wait_flushed(lsn_t sync_lsn)
     write out before we can advance the checkpoint. */
     if (sync_lsn > log_sys.get_flushed_lsn())
       log_write_up_to(sync_lsn, true);
+    DBUG_EXECUTE_IF("ib_log_checkpoint_avoid_hard", return;);
     log_checkpoint();
   }
 }
@@ -1962,6 +1963,8 @@ ATTRIBUTE_COLD void buf_flush_ahead(lsn_t lsn, bool furious)
   if (recv_recovery_is_on())
     recv_sys.apply(true);
 
+  DBUG_EXECUTE_IF("ib_log_checkpoint_avoid_hard", return;);
+
   Atomic_relaxed<lsn_t> &limit= furious
     ? buf_flush_sync_lsn : buf_flush_async_lsn;
 
@@ -2316,6 +2319,7 @@ static os_thread_ret_t DECLARE_THREAD(buf_flush_page_cleaner)(void*)
       buf_pool.page_cleaner_set_idle(true);
 
       DBUG_EXECUTE_IF("ib_log_checkpoint_avoid", continue;);
+      DBUG_EXECUTE_IF("ib_log_checkpoint_avoid_hard", continue;);
 
       mysql_mutex_unlock(&buf_pool.flush_list_mutex);
 
@@ -2399,6 +2403,7 @@ static os_thread_ret_t DECLARE_THREAD(buf_flush_page_cleaner)(void*)
         here should not affect correctness, because log_free_check()
         should still be invoking checkpoints when needed. */
         DBUG_EXECUTE_IF("ib_log_checkpoint_avoid", goto next;);
+        DBUG_EXECUTE_IF("ib_log_checkpoint_avoid_hard", goto next;);
 
         if (!recv_recovery_is_on() && srv_operation == SRV_OPERATION_NORMAL)
           log_checkpoint();

storage/innobase/include/log0log.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2017, 2021, MariaDB Corporation.
+Copyright (c) 2017, 2022, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -460,6 +460,11 @@ struct log_t{
   size_t buf_free;
   /** recommended maximum size of buf, after which the buffer is flushed */
   size_t max_buf_free;
+
+  /** Log sequence number when a log file overwrite (broken crash recovery)
+  was noticed. Protected by mutex. */
+  lsn_t overwrite_warned;
+
   /** mutex to serialize access to the flush list when we are putting
   dirty blocks in the list. The idea behind this mutex is to be able
   to release log_sys.mutex during mtr_commit and still ensure that

storage/innobase/log/log0log.cc

@@ -53,6 +53,7 @@ Created 12/9/1995 Heikki Tuuri
 #include "sync0sync.h"
 #include "buf0dump.h"
 #include "log0sync.h"
+#include "log.h"
 
 /*
 General philosophy of InnoDB redo-logs:
@@ -965,11 +966,20 @@ ATTRIBUTE_COLD void log_write_checkpoint_info(lsn_t end_lsn)
 
 	DBUG_PRINT("ib_log", ("checkpoint ended at " LSN_PF
 			      ", flushed to " LSN_PF,
-			      lsn_t{log_sys.last_checkpoint_lsn},
+			      log_sys.next_checkpoint_lsn,
 			      log_sys.get_flushed_lsn()));
 
 	MONITOR_INC(MONITOR_NUM_CHECKPOINT);
 
+	if (log_sys.overwrite_warned) {
+		sql_print_information("InnoDB: Crash recovery was broken "
+				      "between LSN=" LSN_PF
+				      " and checkpoint LSN=" LSN_PF ".",
+				      log_sys.overwrite_warned,
+				      log_sys.next_checkpoint_lsn);
+		log_sys.overwrite_warned = 0;
+        }
+
 	mysql_mutex_unlock(&log_sys.mutex);
 }
 
@@ -997,10 +1007,15 @@ ATTRIBUTE_COLD static void log_checkpoint_margin()
     const lsn_t sync_lsn= checkpoint + log_sys.max_checkpoint_age;
     if (lsn <= sync_lsn)
     {
+#ifndef DBUG_OFF
+    skip_checkpoint:
+#endif
       log_sys.set_check_flush_or_checkpoint(false);
       goto func_exit;
     }
 
+    DBUG_EXECUTE_IF("ib_log_checkpoint_avoid_hard", goto skip_checkpoint;);
+
     mysql_mutex_unlock(&log_sys.mutex);
 
     /* We must wait to prevent the tail of the log overwriting the head. */

storage/innobase/mtr/mtr0mtr.cc

@@ -24,14 +24,15 @@ Mini-transaction buffer
 Created 11/26/1995 Heikki Tuuri
 *******************************************************/
 
-#include "mtr0mtr.h"
+#include "mtr0log.h"
 
 #include "buf0buf.h"
 #include "buf0flu.h"
 #include "fsp0sysspace.h"
 #include "page0types.h"
-#include "mtr0log.h"
 #include "log0recv.h"
+#include "srv0start.h"
+#include "log.h"
 
 /** Iterate over a memo block in reverse. */
 template <typename Functor>
@@ -759,7 +760,6 @@ mtr_t::memo_release(const void* object, ulint type)
 
 static bool log_margin_warned;
 static time_t log_margin_warn_time;
-static bool log_close_warned;
 static time_t log_close_warn_time;
 
 /** Check margin not to overwrite transaction log from the last checkpoint.
@@ -797,8 +797,8 @@ static void log_margin_checkpoint_age(ulint len)
       log_margin_warned= true;
       log_margin_warn_time= t;
 
-      ib::error() << "innodb_log_file_size is too small "
-                     "for mini-transaction size " << len;
+      sql_print_error("InnoDB: innodb_log_file_size is too small "
+                      "for mini-transaction size " ULINTPF, len);
     }
   }
   else if (UNIV_LIKELY(lsn + margin <= log_sys.last_checkpoint_lsn +
@@ -924,14 +924,19 @@ static mtr_t::page_flush_ahead log_close(lsn_t lsn)
       checkpoint_age != lsn)
   {
     time_t t= time(nullptr);
-    if (!log_close_warned || difftime(t, log_close_warn_time) > 15)
+    if (!log_sys.overwrite_warned || difftime(t, log_close_warn_time) > 15)
     {
-      log_close_warned= true;
+      if (!log_sys.overwrite_warned)
+        log_sys.overwrite_warned= lsn;
       log_close_warn_time= t;
 
-      ib::error() << "The age of the last checkpoint is " << checkpoint_age
-                  << ", which exceeds the log capacity "
-                  << log_sys.log_capacity << ".";
+      sql_print_error("InnoDB: Crash recovery is broken due to"
+                      " insufficient innodb_log_file_size;"
+                      " last checkpoint LSN=" LSN_PF ", current LSN=" LSN_PF
+                      "%s.",
+                      lsn_t{log_sys.last_checkpoint_lsn}, lsn,
+                      srv_shutdown_state != SRV_SHUTDOWN_INITIATED
+                      ? ". Shutdown is in progress" : "");
     }
   }
   else if (UNIV_LIKELY(checkpoint_age <= log_sys.max_modified_age_async))