Mac OS X 10.4.6
Step1: On Mac OS X, click "Finder" and input "smb://10.10.1.44" to connect to Linux PC where the Samba service has already started.
Step2: Login as user "b", enter a public share and find there is a public file names "1.txt". (The owner of "1.txt" is user "a", by command "ls -l" in Linux).
Step3: User "b" open 1.txt, and modify it, then save it.
When I go back to Linux PC and execute "ls -l", I find the owner of 1.txt has been changed!! The owner is changed to user "b", not "a" any more!!
Sorry, there is a mistake in step1.
It should be: Click "connect to server", not "Finder"...
James, handing this one off to you.
This almost certainly depends on the application doing the save. If the application writes to a scratch file and then renames to the final filename, you will see this.