[linux-cifs-client] Re: [PATCH 6/6] cifs: don't retry on blocking sends

[Jeff Layton]

On Sun, 30 Nov 2008 15:39:17 -0600
"Steve French" <smfrench at gmail.com> wrote:

> We probably do need to retry, but closer to the 20 second range total which
> is only slightly longer than the large (non-blocking) send retry used to wait.
> 

I'm not sure I understand this. Why would we need to ever retry the
send? Why not just set the timeout to the value we want and let kernel_sendmsg
do the work?

The timeout value is certainly negotiable though...

> On Sun, Nov 30, 2008 at 7:57 AM, Jeff Layton <jlayton at redhat.com> wrote:
> > smb_send2 will attempt to send a message and retry if it doesn't work.
> > It's rather pointless to do this in the case of blocking sends. We can
> > just set the socket sndtimeo to a reasonable value and try the send
> > once.
> >
> > Why change the timeout to 30s? That seems like a reasonable amount of
> > time to wait for the send. It's also what sunrpc uses for sndtimeo
> > with TCP sockets. At some point we might consider making this
> > tunable, but a generic "timeo" setting similar to what NFS has is
> > probably more user friendly.
> >
> > Signed-off-by: Jeff Layton <jlayton at redhat.com>
> > ---
> >  fs/cifs/connect.c   |    4 ++--
> >  fs/cifs/transport.c |   12 ++++++++++++
> >  2 files changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> > index 25f7cba..16afe2d 100644
> > --- a/fs/cifs/connect.c
> > +++ b/fs/cifs/connect.c
> > @@ -1753,7 +1753,7 @@ ipv4_connect(struct TCP_Server_Info *server)
> >         *  user space buffer
> >         */
> >        socket->sk->sk_rcvtimeo = 7 * HZ;
> > -       socket->sk->sk_sndtimeo = 3 * HZ;
> > +       socket->sk->sk_sndtimeo = 30 * HZ;
> >
> >        /* make the bufsizes depend on wsize/rsize and max requests */
> >        if (server->noautotune) {
> > @@ -1904,7 +1904,7 @@ ipv6_connect(struct TCP_Server_Info *server)
> >         * user space buffer
> >         */
> >        socket->sk->sk_rcvtimeo = 7 * HZ;
> > -       socket->sk->sk_sndtimeo = 3 * HZ;
> > +       socket->sk->sk_sndtimeo = 30 * HZ;
> >        server->ssocket = socket;
> >
> >        return rc;
> > diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> > index 2d1bd28..e4bf0b4 100644
> > --- a/fs/cifs/transport.c
> > +++ b/fs/cifs/transport.c
> > @@ -197,6 +197,18 @@ smb_send2(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> >        while (total_len) {
> >                rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
> >                                    n_vec - first_vec, total_len);
> > +
> > +               /*
> > +                * blocking send -- just update total_len and break out of
> > +                * the loop. No sense in retrying since we've already given
> > +                * it a long timeout.
> > +                */
> > +               if (!server->noblocksnd) {
> > +                       if (rc >= 0)
> > +                               total_len -= rc;
> > +                       break;
> > +               }
> > +
> >                if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
> >                        i++;
> >                        if (i >= 14) {
> > --
> > 1.5.5.1
> >
> >
> 
> 
> 
> -- 
> Thanks,
> 
> Steve


-- 
Jeff Layton <jlayton at redhat.com>