[PATCH#3] fake data io module for samba

[Peter Somogyi]

Volker Lendecke <Volker.Lendecke at SerNet.DE> wrote on 12/27/2014 12:44:48 
PM:
> On Fri, Dec 26, 2014 at 12:41:32PM -0700, Christof Schmitt wrote:
> > Having a user explicitly set "fake_io:destroy data" to "yes", should 
be
> > a sufficient warning.
> 
> Sounds good.

Ok adding it on ToDo.

> 
> > For shares with async i/o enabled, you probably also need to intercept 
the
> > async calls (pread_send, pwrite_send).

I did not intend to support aio as I had concern being asys_pread_do not 
on the VFS:

     ret = pthreadpool_add_job(ctx->pool, jobid, asys_pread_do, job);

Maybe let me chose code duplication (although I fear of future breakage), 
seeing the VFS addition harder achieve.

> 
> Yep. One thing this module could test would be some
> arbitrary or random delay in the async pread/pwrite
> operations in order to test the for example our client-side
> crediting algorithm. If we hold back some requests
> server-side, the client should fill the pipe according to
> the available credits and continue when they become
> available.
> 
> Volker

Volker, did you mean adding the delay to the beginning of the whole 
vfswrap_pread_recv/send, or just the async parts 
[asys_pread_do/asys_pwrite_do] (which are not on the VFS) ?
I assume vfswrap_pread_recv/send VFS calls were designed to return 
immediately.
I'd add 'fake_io:read delay' and 'fake_io:write delay' if non-zero in 
microsec. usleep then, for both aio/non-aio pread/write.

--
Peter Somogyi
IBM Magyarországi Kft.
1117 Budapest
Infopark, Neumann János u. 1.
Hungary
Phone: +36 1 382 5469