kernel support for open share modes

[Jeremy Allison]

On Fri, Feb 04, 2005 at 02:26:23PM -0500, J. Bruce Fields wrote:
> How does Samba currently handle deny share modes?  Are they coordinated
> with local access?  (Does a local open fail if the file is opened with a
> conflicting deny mode by a samba client?)
> 
> I'm interested because we'd like to support something similar for NFSv4,
> and it doesn't seem that existing kernel support is sufficient to do it
> correctly.
> 
> This looks like a hard problem, but I'd be curious whether anyone had
> thought about it and had any ideas.

In Linux Samba makes a kernel call to flock to tell the kernel about
Samba-related deny modes, but only on Linux. Look for the kernel_flock
code in smbd/open.c. Samba handles deny modes in memory, and they are
not coordinated with local access.

Jeremy.