Dear all,

I found in all versions of Linux (at least for kernel version 4/5/6), the following bug exists: When a user is granted full access to a file of which he is not the owner, he can read/write/delete the file, but cannot "change only its last modification date". In particular, `touch -m` fails and Python's `os.utime()` also fails with "Operation not permitted", but `touch` without -m works.

This applies to both FACL extended permission as well as basic Linux file permission.

Thank you for fixing this in the future!

Cheers, Xuancong