mariabackup incorrectly tries to open ibdata1 if custom undo tablespace is defined

[mariadb-10.2]

log_error=mysqld.err

datadir=/datadir

innodb_data_home_dir=/datadir/data

innodb_data_file_path = ib_mysql2_01:1G:autoextend

innodb_log_group_home_dir = /datadir/logs

innodb_undo_directory = /datadir/undologs

innodb_undo_log_truncate = 1

innodb_undo_logs = 128

innodb_undo_tablespaces = 32

mariabackup --backup --databases=mysql --no-lock --parallel=10 --compress --compress-threads=10 --user=root --target-dir=/home/ec2-user/backup

180918 18:26:12 Connecting to MySQL server host: localhost, user: root, password: not set, port: not set, socket: not set

Using server version 10.2.16-MariaDB

Loading encryption plugin

         Encryption plugin parameter :  '--aws_key_management_key_spec=AES_128'

         Encryption plugin parameter :  '--aws_key_management_log_level=Off'

         Encryption plugin parameter :  '--aws_key_management_master_key_id='

         Encryption plugin parameter :  '--aws_key_management_region='

         Encryption plugin parameter :  '--aws_key_management_request_timeout=0'

         Encryption plugin parameter :  '--aws_key_management_rotate_key=0'

mariabackup based on MariaDB server 10.2.16-MariaDB Linux (x86_64)

mariabackup: uses posix_fadvise().

mariabackup: cd to /datadir/data/

mariabackup: open files limit requested 0, set to 1024

mariabackup: using the following InnoDB configuration:

mariabackup:   innodb_data_home_dir = /datadir/data

mariabackup:   innodb_data_file_path = ib_mysql2_01:1G:autoextend

mariabackup:   innodb_log_group_home_dir = /datadir/logs

2018-09-18 18:26:12 139964570237056 [Note] InnoDB: Number of pools: 1

2018-09-18 18:26:12 139964570237056 [ERROR] InnoDB: Operating system error number 2 in a file operation.

2018-09-18 18:26:12 139964570237056 [ERROR] InnoDB: The error means the system cannot find the path specified.

2018-09-18 18:26:12 139964570237056 [ERROR] InnoDB: If you are installing InnoDB, remember that you must create directories yourself, InnoDB does not create them.

2018-09-18 18:26:12 139964570237056 [ERROR] InnoDB: File /datadir/data/ibdata1: 'open' returned OS error 71. Cannot continue operation

180918 18:26:12 [ERROR] mysqld got signal 6 ;

This could be because you hit a bug. It is also possible that this binary

or one of the libraries it was linked against is corrupt, improperly built,

or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help

diagnose the problem, but since we have already crashed,

something is definitely wrong and this may fail.

Server version: 10.2.16-MariaDB

key_buffer_size=0

read_buffer_size=131072

max_used_connections=0

max_threads=1

thread_count=0

It is possible that mysqld could use up to

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 5422 K  bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x0

Attempting backtrace. You can use the following information to find out

where mysqld died. If you see no messages after this, something went

terribly wrong...

stack_bottom = 0x0 thread_stack 0x49000

addr2line: 'mariabackup': No such file

mariabackup(my_print_stacktrace+0x2e)[0x7f4c0b43391e]

mariabackup(handle_fatal_signal+0x355)[0x7f4c0af1ffb5]

sigaction.c:0(__restore_rt)[0x7f4c0a3ea370]

:0(__GI_raise)[0x7f4c089741d7]

:0(__GI_abort)[0x7f4c089758c8]

addr2line: 'mariabackup': No such file

mariabackup(+0x9aeff5)[0x7f4c0b1c7ff5]

mariabackup(+0x423bcf)[0x7f4c0ac3cbcf]

mariabackup(+0x424142)[0x7f4c0ac3d142]

mariabackup(+0x45cc8a)[0x7f4c0ac75c8a]

mariabackup(main+0x185)[0x7f4c0ac53365]

/lib64/libc.so.6(__libc_start_main+0xf5)[0x7f4c08960b35]

addr2line: 'mariabackup': No such file

mariabackup(+0x4539cd)[0x7f4c0ac6c9cd]

The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains

information that should help you find out what is causing the crash.

stat("/datadir/data/ib_mysql2_01", {st_mode=S_IFREG|0660, st_size=1073741824, ...}) = 0

access("/datadir/data/ib_mysql2_01", R_OK) = 0

open("/datadir/data/ib_mysql2_01", O_RDONLY|O_CLOEXEC) = 6

fstat(6, {st_mode=S_IFREG|0660, st_size=1073741824, ...}) = 0

mmap(NULL, 135168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4c0a61d000

pread64(6, "\230\267R\365\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\27\200\300\0\10\0\0\0\0\0\27"..., 65536, 0) = 65536

close(6)                                = 0

open("/datadir/data/ibdata1", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)