When trying to setup a new linux pool which mounts home dirs from remote by
using cifs, i noticed that there seems to be a bug in the handling of the
permissions when changing them.

In particular it seems that samba enforces permission not to be more than the
create mask, even when changing it. If i have the "create mask" set to 0600 in
samba.conf (which is a reasonable value), a user can not set the executable flag
of the file. He can set and remove the read and write flags, and can remove an
executable flag from a file which has already one - but can not set it again.

When setting "create mask" to 0700, the user can modify all three flags (read,
write, executable) without problems, but every new file created would be
automatically 0700 which is not what i want.

I tried playing with "security mask" and other options but found no solution. It
seems i'm not the only one, who has notices this problems, on google i found the
following report which is the same problem:
http://lists.samba.org/archive/samba/2004-July/089533.html

I think this is a bug, because the "create mask" value should not make any
difference when modifying an already existing file.