On Sat, Dec 4, 2010 at 7:09 AM, Jeff Layton <jlayton@xxxxxxxxx> wrote: > On Sat, 4 Dec 2010 06:25:07 -0600 > Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote: > >> On Sat, Dec 4, 2010 at 5:44 AM, Jeff Layton <jlayton@xxxxxxxxx> wrote: >> >> > On Sat, 4 Dec 2010 09:13:21 +0100 >> > Volker Lendecke <Volker.Lendecke@xxxxxxxxx> wrote: >> > >> > > On Fri, Dec 03, 2010 at 09:54:13PM -0600, Christopher R. Hertel wrote: >> > > > That may seem to be in the "who cares" category, since those old >> > transports >> > > > are essentially dead (much more dead than NBT, or even NBF). >> > Unfortunately, >> > > > the code to handle the old transports is still there in Windows, so >> > there >> > > > are behaviors -- things like the timeouts you're talking about and the >> > weird >> > > > VC=0 shutdown behvior -- that exist because of these old disused >> > transports. >> > > >> > > VC=0, how does Windows treat this facing NAT (masquerading) >> > > networks? I've done tests in the past where Windows killed >> > > valid connections from behind a NAT box when a new client >> > > came in. >> > > >> > > Volker >> > >> > It seems like the best way to deal with this on the server side with >> > direct hosted TCP would be to treat VC=0 like any other VC number >> > (MS-CIFS says that this is allowed). >> > >> > Ideally any new connection event from a host however should make the >> > server check the validity of any other connection from the same host. >> > That way you could release resources held by dead connections in case >> > the new one is a reconnect and needs to reclaim state. >> > >> > The question is how to check that validity. Unfortunately, the best you >> > can probably do is rely on TCP keepalives. >> > >> > -- >> > Jeff Layton <jlayton@xxxxxxxxx> >> > -- >> > To unsubscribe from this list: send the line "unsubscribe linux-cifs" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> > >> >> >> Is SMB Echo command the only way to determine whether to reconnect or not? >> The assumption here is SMB server is unresponsive. >> There could be other circumstances on the server box (or even client box) >> that are >> slowing down the SMB server responses such as slow network, slow network >> stack, >> memory pressure etc. >> So server could be fine all along and yet client would ask for reconnection! > > I think it's the best mechanism that the protocol has. If we aren't > going to use SMB echoes to detect an unresponsive server, then what > would you suggest? I don't think we can make calls wait indefinitely > for a response without a mechanism to determine when the server is gone > and attempt to reestablish the connection to it. > > -- > Jeff Layton <jlayton@xxxxxxxxx> > I think we should use smb echo command as a means to let users know the state of mount/server and let them decide. If smb echo times out, cifs client should just log it and stop at that and a very next request that receives a response (if any does) should log that server is responding. -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
