Openstack-suse virtual machine-deleted files are automatically restored

We opened a virtual machine running suse linux server 12 on the openstack platform, and it worked normally at the beginning.
later found a problem: some files and directories cannot be deleted even if they are deleted.
if / home/mysql/ has many files with the suffix "tar.gz", the files deleted today will be automatically restored tomorrow. Have you ever encountered this problem?

the file system is Ext4;

Mar.03,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-7b7503-1ed69.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-7b7503-1ed69.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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