MDEV-18200 MariaBackup full backup failed with InnoDB: Failing assertion: success

There are many filesystem related errors that can occur with
MariaBackup. These already outputed to stderr with a good description of
the error. Many of these are permission or resource (file descriptor)
limits where the assertion and resulting core crash doesn't offer
developers anything more than the log message. To the user, assertions
and core crashes come across as poor error handling.

As such we return an error and handle this all the way up the stack.

extra/mariabackup/xtrabackup.cc

@@ -4503,14 +4503,21 @@ bool Backup_datasinks::backup_low()
 
 		if (recv_find_max_checkpoint(&max_cp_field) == DB_SUCCESS
 		    && log_sys.log.format != 0) {
-			if (max_cp_field == LOG_CHECKPOINT_1) {
+			switch (max_cp_field) {
-				log_header_read(max_cp_field);
+			case LOG_CHECKPOINT_1:
+				if (log_header_read(max_cp_field)) {
+					/* metadata_to_lsn still 0 so error returns below */
+					msg("Error: recv_find_max_checkpoint() failed.");
+					break;
+				}
+				/* fallthrough */
+			default:
+				metadata_to_lsn = mach_read_from_8(
+					log_sys.checkpoint_buf + LOG_CHECKPOINT_LSN);
+				msg("mariabackup: The latest check point"
+				    " (for incremental): '" LSN_PF "'",
+				    metadata_to_lsn);
 			}
-			metadata_to_lsn = mach_read_from_8(
-				log_sys.checkpoint_buf + LOG_CHECKPOINT_LSN);
-			msg("mariabackup: The latest check point"
-			    " (for incremental): '" LSN_PF "'",
-			    metadata_to_lsn);
 		} else {
 			msg("Error: recv_find_max_checkpoint() failed.");
 		}
@@ -4721,7 +4728,11 @@ reread_log_header:
 	checkpoint_lsn_start = log_sys.log.get_lsn();
 	checkpoint_no_start = log_sys.next_checkpoint_no;
 
-	log_header_read(max_cp_field);
+	if (log_header_read(max_cp_field)) {
+		log_mutex_exit();
+		goto fail;
+	}
+
 
 	if (checkpoint_no_start != mach_read_from_8(buf + LOG_CHECKPOINT_NO)
 	    || checkpoint_lsn_start

mysql-test/suite/mariabackup/data_directory.result

@@ -11,3 +11,9 @@ SELECT * FROM t;
 a
 1
 DROP TABLE t;
+#
+# MDEV-18200 MariaBackup full backup failed with InnoDB: Failing assertion: success
+#
+#
+# End of 10.4 tests
+#

mysql-test/suite/mariabackup/data_directory.test

@@ -21,4 +21,19 @@ rmdir $table_data_dir;
 SELECT * FROM t;
 DROP TABLE t;
 rmdir $targetdir;
+
+--echo #
+--echo # MDEV-18200 MariaBackup full backup failed with InnoDB: Failing assertion: success
+--echo #
+let $DATADIR= `select @@datadir`;
+chmod 0000 $DATADIR/ibdata1;
+--disable_result_log
+--error 1
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir;
+--enable_result_log
+chmod 0755 $DATADIR/ibdata1;
 rmdir $table_data_dir;
+rmdir $targetdir;
+--echo #
+--echo # End of 10.4 tests
+--echo #

plugin/cracklib_password_check/CMakeLists.txt

@@ -1,3 +1,9 @@
+
+IF(PLUGIN_CRACKLIB_PASSWORD_CHECK STREQUAL "NO")
+  ADD_FEATURE_INFO(CRACKLIB_PASSWORD_CHECK "OFF" "CrackLib Password Validation Plugin")
+  RETURN()
+ENDIF()
+
 INCLUDE (CheckIncludeFiles)
 INCLUDE (CheckLibraryExists)
 

storage/innobase/fil/fil0fil.cc

@@ -557,7 +557,9 @@ fail:
 			&success);
 	}
 
-	ut_a(success);
+	if (!success)
+		return false;
+
 	ut_a(node->is_open());
 
 	fil_system.n_open++;
@@ -4062,8 +4064,10 @@ inline void IORequest::set_fil_node(fil_node_t* node)
 @param[in] message	message for aio handler if non-sync aio
 			used, else ignored
 @param[in] ignore_missing_space true=ignore missing space duging read
-@return DB_SUCCESS, or DB_TABLESPACE_DELETED
+@retval DB_SUCCESS, if successful; or
-	if we are trying to do i/o on a tablespace which does not exist */
+@retval DB_IO_ERROR, if unable to open file or the purpose==FIL_TYPE_IMPORT; or
+@retval DB_TABLESPACE_DELETED, if we are trying to do i/o on a tablespace which
+        does not exist */
 dberr_t
 fil_io(
 	const IORequest&	type,
@@ -4232,11 +4236,13 @@ fil_io(
 			return(DB_TABLESPACE_DELETED);
 		}
 
-		/* The tablespace is for log. Currently, we just assert here
+		/* The tablespace is for log. We used to asssert here
 		to prevent handling errors along the way fil_io returns.
 		Also, if the log files are missing, it would be hard to
-		promise the server can continue running. */
+		promise the server can continue running. However this
-		ut_a(0);
+		is also used by MariaDB-backup, so we need to handle it. */
+		mutex_exit(&fil_system.mutex);
+		return(DB_IO_ERROR);
 	}
 
 	/* Check that at least the start offset is within the bounds of a

storage/innobase/include/log0log.h

@@ -209,8 +209,9 @@ void
 logs_empty_and_mark_files_at_shutdown(void);
 /*=======================================*/
 /** Read a log group header page to log_sys.checkpoint_buf.
-@param[in]	header	0 or LOG_CHECKPOINT_1 or LOG_CHECKPOINT2 */
+@param[in]	header	0 or LOG_CHECKPOINT_1 or LOG_CHECKPOINT2
-void log_header_read(ulint header);
+@return error code (from fil_io) or DB_SUCCESS */
+dberr_t log_header_read(ulint header);
 /** Write checkpoint info to the log header and invoke log_mutex_exit().
 @param[in]	sync	whether to wait for the write to complete
 @param[in]	end_lsn	start LSN of the MLOG_CHECKPOINT mini-transaction */

storage/innobase/log/log0log.cc

@@ -1355,20 +1355,21 @@ log_group_checkpoint(lsn_t end_lsn)
 }
 
 /** Read a log group header page to log_sys.checkpoint_buf.
-@param[in]	header	0 or LOG_CHECKPOINT_1 or LOG_CHECKPOINT2 */
+@param[in]	header	0 or LOG_CHECKPOINT_1 or LOG_CHECKPOINT2
-void log_header_read(ulint header)
+@return         DB_SUCCESS or error. */
+dberr_t log_header_read(ulint header)
 {
-	ut_ad(log_mutex_own());
+  ut_ad(log_mutex_own());
 
-	log_sys.n_log_ios++;
+  log_sys.n_log_ios++;
 
-	MONITOR_INC(MONITOR_LOG_IO);
+  MONITOR_INC(MONITOR_LOG_IO);
 
-	fil_io(IORequestLogRead, true,
+  return fil_io(IORequestLogRead, true,
-	       page_id_t(SRV_LOG_SPACE_FIRST_ID,
+                page_id_t(SRV_LOG_SPACE_FIRST_ID,
-			 header >> srv_page_size_shift),
+                          header >> srv_page_size_shift),
-	       0, header & (srv_page_size - 1),
+                0, header & (srv_page_size - 1),
-	       OS_FILE_LOG_BLOCK_SIZE, log_sys.checkpoint_buf, NULL);
+                OS_FILE_LOG_BLOCK_SIZE, log_sys.checkpoint_buf, NULL);
 }
 
 /** Write checkpoint info to the log header and invoke log_mutex_exit().

storage/innobase/log/log0recv.cc

@@ -1068,6 +1068,7 @@ recv_find_max_checkpoint_0(ulint* max_field)
 {
 	ib_uint64_t	max_no = 0;
 	ib_uint64_t	checkpoint_no;
+	dberr_t		err;
 	byte*		buf	= log_sys.checkpoint_buf;
 
 	ut_ad(log_sys.log.format == 0);
@@ -1085,7 +1086,8 @@ recv_find_max_checkpoint_0(ulint* max_field)
 
 	for (ulint field = LOG_CHECKPOINT_1; field <= LOG_CHECKPOINT_2;
 	     field += LOG_CHECKPOINT_2 - LOG_CHECKPOINT_1) {
-		log_header_read(field);
+		if ((err= log_header_read(field)))
+			return err;
 
 		if (static_cast<uint32_t>(ut_fold_binary(buf, CHECKSUM_1))
 		    != mach_read_from_4(buf + CHECKSUM_1)
@@ -1208,13 +1210,15 @@ recv_find_max_checkpoint(ulint* max_field)
 	ib_uint64_t	checkpoint_no;
 	ulint		field;
 	byte*		buf;
+	dberr_t		err;
 
 	max_no = 0;
 	*max_field = 0;
 
 	buf = log_sys.checkpoint_buf;
 
-	log_header_read(0);
+	if ((err= log_header_read(0)))
+		return err;
 	/* Check the header page checksum. There was no
 	checksum in the first redo log format (version 0). */
 	log_sys.log.format = mach_read_from_4(buf + LOG_HEADER_FORMAT);
@@ -1252,7 +1256,8 @@ recv_find_max_checkpoint(ulint* max_field)
 	for (field = LOG_CHECKPOINT_1; field <= LOG_CHECKPOINT_2;
 	     field += LOG_CHECKPOINT_2 - LOG_CHECKPOINT_1) {
 
-		log_header_read(field);
+		if ((err= log_header_read(field)))
+			return err;
 
 		const ulint crc32 = log_block_calc_checksum_crc32(buf);
 		const ulint cksum = log_block_get_checksum(buf);
@@ -3630,7 +3635,8 @@ recv_recovery_from_checkpoint_start(lsn_t flush_lsn)
 		return(err);
 	}
 
-	log_header_read(max_cp_field);
+	if ((err= log_header_read(max_cp_field)))
+		return err;
 
 	buf = log_sys.checkpoint_buf;