How does Samba Solve this problem?

[zhangyfh at legend.com.cn]

As we know, in linux, there's no the concept of DENY MODE.
In M$ windows, when open a file, you use the API
CreateFile (LPCTSTR lpFileName,
     DWORD dwDesiredAccess,
     DWORD dwShareMode,
     LPSECURITY_ATTRIBUTES lpSecurityAttributes,
     DWORD dwCreationDistribution,
     DWORD dwFlagsAndAttributes,
     HANDLE hTemplateFile)

the parameter dwShareMode define the deny mode, fo example, if open a file
with DENY_WRITE, aother applications can't write this file.
When M$ WORD open a file, then other applications can't write the same
file.

But in Linux , when open a file you use open(char *fname, int mode),
there's no DENY MODE.

So my question is that, What does Samba do to propose an open request with
DENY MODE from a window client.