Ive got homes share: [homes] writable = yes browseable = yes create mask = 0600 directory mask = 0700 I put in this share file: -r--r--r-- 1 root root 444 Jan 14 00:12 rules.txt In this case users cannot delete or change the file, but they can rename it. I think it's serious bug. You can use chattr +i rules.txt to avoid this, however extensively using of immutable flag broke my ext3 partition recently (in begining I was unable to delete file with no "i" set, after I did chattr -R - i /home then all permission messed up badly (I use winbind also)
Samba relies on the underlying file system to enforce permissions. I duplicated the behavior you describe from windows explorer. But also from a shell prompt on the linux server as a normal user. If you think this is a bug, you'll apparently have to convince the file ext2/ext3 maintainers of it.
database cleanup