kernel support for open share modes

[Michael B Allen]

Jeremy Allison said:
> On Tue, Feb 15, 2005 at 04:30:28AM -0500, Michael B Allen wrote:
>>
>> I believe it's generally accepted that there are certain
>> incompatibilities
>> and limitations between the protocols and the POSIX APIs that prevent
>> proper coordination for many operations. POSIX simply isn't
>> sophisticated
>> enough to implement a full featured userspace network filesystem in a
>> way that can communicate consistent systemwide state. POSIX was designed
>> to be simple (I guess because it's more secure).
>
> Slightly off topic I suppose, but it always irks me to see
> people refer to concepts like deny modes as "sophisticated".
> Complex, yes. Sophisticated, no.

Well I don't believe I said that exactly. What I said was that POSIX isn't
sophisticated enough to properly implement a userspace network filesystem.

Specifically, when using only the POSIX APIs, there is a race condition
between examining ACLs, share modes, or other file meta data, and acting
on that information such as opening or deleting the target file.

Mike