Question on continuous EIOs in CIFS protocol

Richard Sharpe realrichardsharpe at
Thu Sep 18 11:17:12 MDT 2014

On Thu, Sep 18, 2014 at 10:08 AM, Volker Lendecke
<Volker.Lendecke at> wrote:
> Hi!
> Windows servers expect writes to succeed unless there's a
> real error like a full disk or permission denied or so.
> There won't be a retry. The retry logic needs to live within
> smbd completely.
> For a VFS that goes out to a socket and not to a local
> syscall, I would recommend that you look at our async I/O.
> With Samba 4.1 we have implemented very flexible VFS
> operations (pread_send/recv and pwrite_send/recv) that are
> able to handle this nicely. In case you're sitting on an
> earlier version, you need to take a look at
> aio_read/aio_write/aio_return. Not as flexibile, but you can
> also implement async retry logic there.
> It would be best if you would post your VFS module source
> somewhere (it's GPL in the end :-)) so that we can make
> recommendations.

What he didn't tell you is that it is Samba 3.5.15 or so and they are
using the Async IO stuff in that version.

Richard Sharpe

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