MDEV-28289 fts_optimize_sync_table() is acquiring dict_sys.latch while holding it

dict_acquire_mdl_shared(): Invoke the correct variant
dict_table_t::parse_name<true>() also when trylock=true,
that is, we are being called from fts_optimize_sync_table().

Ever since commit 82b7c561b7 (MDEV-24258)
this code was prone to a hang. If another thread requested an
exclusive dict_sys.latch between the time
dict_acquire_mdl_shared<trylock=true>() acquired a shared dict_sys.latch
and dict_table_t::parse_name<false>() was trying to acquire another
shared dict_sys.latch, InnoDB would get into an infinite livelock
of threads, because the futex-based srw-lock implementation prioritizes
exclusive latch requests.

dict_table_t::parse_name(): Rename the template parameter dict_locked
into dict_frozen.

storage/innobase/dict/dict0dict.cc

@@ -602,13 +602,13 @@ dict_index_get_nth_field_pos(
 }
 
 /** Parse the table file name into table name and database name.
-@tparam		dict_locked	whether dict_sys.lock() was called
-@param[in,out]	db_name		database name buffer
-@param[in,out]	tbl_name	table name buffer
-@param[out]	db_name_len	database name length
-@param[out]	tbl_name_len	table name length
+@tparam        dict_frozen  whether the caller holds dict_sys.latch
+@param[in,out] db_name      database name buffer
+@param[in,out] tbl_name     table name buffer
+@param[out] db_name_len     database name length
+@param[out] tbl_name_len    table name length
 @return whether the table name is visible to SQL */
-template<bool dict_locked>
+template<bool dict_frozen>
 bool dict_table_t::parse_name(char (&db_name)[NAME_LEN + 1],
                               char (&tbl_name)[NAME_LEN + 1],
                               size_t *db_name_len, size_t *tbl_name_len) const
@@ -616,7 +616,7 @@ bool dict_table_t::parse_name(char (&db_name)[NAME_LEN + 1],
   char db_buf[MAX_DATABASE_NAME_LEN + 1];
   char tbl_buf[MAX_TABLE_NAME_LEN + 1];
 
-  if (!dict_locked)
+  if (!dict_frozen)
     dict_sys.freeze(SRW_LOCK_CALL); /* protect against renaming */
   ut_ad(dict_sys.frozen());
   const size_t db_len= name.dblen();
@@ -636,7 +636,7 @@ bool dict_table_t::parse_name(char (&db_name)[NAME_LEN + 1],
   memcpy(tbl_buf, mdl_name.m_name + db_len + 1, tbl_len);
   tbl_buf[tbl_len]= 0;
 
-  if (!dict_locked)
+  if (!dict_frozen)
     dict_sys.unfreeze();
 
   *db_name_len= filename_to_tablename(db_buf, db_name,
@@ -782,7 +782,7 @@ return_without_mdl:
 
   size_t db1_len, tbl1_len;
 
-  if (!table->parse_name<!trylock>(db_buf1, tbl_buf1, &db1_len, &tbl1_len))
+  if (!table->parse_name<true>(db_buf1, tbl_buf1, &db1_len, &tbl1_len))
   {
     /* The table was renamed to #sql prefix.
     Release MDL (if any) for the old name and return. */

storage/innobase/include/dict0dict.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1996, 2018, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2021, MariaDB Corporation.
+Copyright (c) 2013, 2022, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1570,7 +1570,7 @@ public:
     }
     else
       lock_wait(SRW_LOCK_ARGS(file, line));
-   }
+  }
 
 #ifdef UNIV_PFS_RWLOCK
   /** Unlock the data dictionary cache. */

storage/innobase/include/dict0mem.h

@@ -2,7 +2,7 @@
 
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
-Copyright (c) 2013, 2021, MariaDB Corporation.
+Copyright (c) 2013, 2022, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -1934,17 +1934,17 @@ struct dict_table_t {
 	/** For overflow fields returns potential max length stored inline */
 	inline size_t get_overflow_field_local_len() const;
 
-	/** Parse the table file name into table name and database name.
-	@tparam		dict_locked	whether dict_sys.lock() was called
-	@param[in,out]	db_name		database name buffer
-	@param[in,out]	tbl_name	table name buffer
-	@param[out]	db_name_len	database name length
-	@param[out]	tbl_name_len	table name length
-	@return whether the table name is visible to SQL */
-	template<bool dict_locked= false>
-	bool parse_name(char (&db_name)[NAME_LEN + 1],
-			char (&tbl_name)[NAME_LEN + 1],
-			size_t *db_name_len, size_t *tbl_name_len) const;
+  /** Parse the table file name into table name and database name.
+  @tparam        dict_frozen  whether the caller holds dict_sys.latch
+  @param[in,out] db_name      database name buffer
+  @param[in,out] tbl_name     table name buffer
+  @param[out] db_name_len     database name length
+  @param[out] tbl_name_len    table name length
+  @return whether the table name is visible to SQL */
+  template<bool dict_frozen= false>
+  bool parse_name(char (&db_name)[NAME_LEN + 1],
+                  char (&tbl_name)[NAME_LEN + 1],
+                  size_t *db_name_len, size_t *tbl_name_len) const;
 
   /** Clear the table when rolling back TRX_UNDO_EMPTY */
   void clear(que_thr_t *thr);