Full text index runs out of storage

[Hor Kol]

I have a table with 1 MEDIUMTEXT column.
Table has 130,000 rows, size is about 3GB

When I try to add full text index:

ALTER TABLE `mydb`.`mytable`
ADD FULLTEXT INDEX `textfull` (`text`) VISIBLE;
;

I get error
Error Code: 1030. Got error 100 - 'InnoDB error' from storage engine

There is 13GB available disk space.

I have change tmpdir to my temp dir, but doesn't work.

Can you help me?