best strategy for preventing unnecessary oplock breaks on doubly open files

[Jeremy Allison]

On Wed, Oct 12, 2005 at 11:07:26AM +1000, tridge at samba.org wrote:
> Jeremy,
> 
>  > What about adding a reaquire oplock call into the UNIX extentions ?
> 
> It might be better just to support the existing FSTCL ntiocl calls for
> oplocks. These are supported by windows on local filesystems, but not
> on remote filesystems. We can easily support them on remote
> filesystems too. They are:
> 
> #define FSCTL_REQUEST_OPLOCK_LEVEL_1 (FSCTL_FILESYSTEM | (0<<2))
> #define FSCTL_REQUEST_OPLOCK_LEVEL_2 (FSCTL_FILESYSTEM | (1<<2))
> #define FSCTL_REQUEST_BATCH_OPLOCK   (FSCTL_FILESYSTEM | (2<<2))
> 
> w2k3 returns NT_STATUS_NOT_SUPPORTED on these, but at least their
> existance on local filesystems means that the numbers are reserved,
> and if windows ever does support this then its a pretty good bet they
> will use these same opcodes.

Ok, do we know what the data on the wire should look like ? The
only reason for not doing so would be if we can't figure out what
the actual bits should be (although it looks pretty simple - can't
see that they need any really).

Jeremy.