Bug #107858 truncate table not free mutex in some case

• Submitted: 13 Jul 2022 7:14
• Modified: 22 Aug 2022 19:41
• Reporter: WANG GUANGYOU
• Status: Closed
• Category: MySQL Server: InnoDB storage engine
• Severity: S3 (Non-critical)
• Version: 5.7
• OS: Any
• CPU Architecture: Any

[13 Jul 2022 7:14] WANG GUANGYOU

Description:
check the code. ####################

dberr_t
truncate_t::truncate(
/*=================*/
	ulint		space_id,
	const char*	dir_path,
	const char*	tablename,
	ulint		flags,
	bool		trunc_to_default)
{
	dberr_t		err = DB_SUCCESS;
	char*		path;
	bool		has_data_dir = FSP_FLAGS_HAS_DATA_DIR(flags);

	ut_a(!is_system_tablespace(space_id));

	if (has_data_dir) {
		ut_ad(dir_path != NULL);

		path = fil_make_filepath(dir_path, tablename, IBD, true);

	} else {
		path = fil_make_filepath(NULL, tablename, IBD, false);
	}

	if (path == NULL) {
		return(DB_OUT_OF_MEMORY);
	}
####################################### enter mutex
	mutex_enter(&fil_system->mutex);

	fil_space_t*	space = fil_space_get_by_id(space_id);

	/* The following code must change when InnoDB supports
	multiple datafiles per tablespace. */
	ut_a(UT_LIST_GET_LEN(space->chain) == 1);

	fil_node_t*	node = UT_LIST_GET_FIRST(space->chain);

	if (trunc_to_default) {
		space->size = node->size = FIL_IBD_FILE_INITIAL_SIZE;
	}

	const bool already_open = node->is_open;

	if (!already_open) {

		bool	ret;

		node->handle = os_file_create_simple_no_error_handling(
			innodb_data_file_key, path, OS_FILE_OPEN,
			OS_FILE_READ_WRITE,
			fsp_is_system_temporary(space_id)
			? false : srv_read_only_mode, &ret);

		if (!ret) {
			ib::error() << "Failed to open tablespace file "
				<< path << ".";

			ut_free(path);
############################ return without exit mutex
			return(DB_ERROR);
		}

		node->is_open = true;
	}

How to repeat:
check the code

[13 Jul 2022 12:29] MySQL Verification Team

Hi Mr. GUANGYOU,

Thank you for your bug report.

[13 Jul 2022 12:30] MySQL Verification Team

Hi Mr. GUANGYOU,

Thank you for your bug report.

We have discovered that you are correct about your report, but only in the version 5.7. Version 8.0 is totally re-organised in most of its code, including the row truncation.

Verified as 5.7-only bug.

[22 Aug 2022 19:41] Daniel Price

Posted by developer:
 
Fixed as of the upcoming 8.0.31 release:

A TRUNCATE TABLE operation failed to free an acquired mutex in specific
cases.

[22 Aug 2022 22:40] Tsubasa Tanaka

> [13 Jul 12:30] MySQL Verification Team
says "Verified as 5.7-only bug.", but

> Fixed as of the upcoming 8.0.31 release:

At last, is this affected both 5.7 and 8.0?