Re: PUFFS putpages/read race?

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Jul 20, 2012 at 03:24:03AM +0200, Emmanuel Dreyfus wrote:
> Hi
> 
> I suspect I have another possible race between putpages and read.
> 
> If page cache is used, VOP_PUTPAGES for PUFFS calls Fire-And-Forget
> write operations. That means the kernel sends the write request and does
> not wait for the reply.  The kernel therefore has no way to know when
> the operation completed.

If, nonetheless, the user processs returns inconsistent data for a
subsequent read, that is a bug.  In the user process, I would say.
The user process *must* preserve ordering of reads and writes to the
same underlying resource.