On Feb 24, 2011, at 5:36 AM, Shiraz Hashim wrote: > On Thu, Feb 10, 2011 at 05:26:16AM +0800, Chuck Lever wrote: >> >> On Feb 9, 2011, at 3:58 PM, Brian Downing wrote: >> >>> On Wed, Feb 09, 2011 at 03:12:22PM -0500, Chuck Lever wrote: >>>> Based on your console logs, I see that the working case uses UDP to >>>> contact the server's mountd, but the failing case uses TCP. You can >>>> try explicitly specifying "proto=udp" to force the use of UDP, to test >>>> this theory. >>> >>> This does indeed make it work again for me, thanks! >>> >>>> Meanwhile, the patch description explicitly states that the default >>>> mount option settings have changed. Does it make sense to change the >>>> default behavior of NFSROOT mounts to use UDP again? I don't see >>>> another way to make this process more reliable across NIC >>>> initialization. If this is considered a regression, we can make a >>>> patch for 2.6.38-rc and 2.6.37. >>> >>> I only use nfsroot for development, so I don't have a terribly strong >>> opinion. I would point out though that the default u-boot parameters >>> for nfsrooting a lot of boards will no longer work at this point, so if >>> it's not patched to work again without specifying nfs options I think >>> there should at least be a note in the documentation and possibly a >>> "maybe try proto=udp?" console message on failure. >>> >>> I assume it's not feasable to either wait until the chosen interface's >>> link is ready before trying to mount nfsroot, or retrying TCP-based >>> connections a little bit more aggressively/at all? >> >> Our goal is to use the same mount logic for both normal user >> space mounts and for NFSROOT (that was the purpose of the patch >> series this particular patch comes from). It's >> exceptionally difficult to add a special case for retrying TCP >> connections here, as that would change the behavior of user >> space mounts, which often want to fail quickly, and don't need >> to worry about NIC initialization. >> >> Sounds like the right thing to do is restore the default UDP behavior. I'll cook up a patch. > > Is there some patch available for this now. Yes, it was posted a couple of weeks ago (sorry, I don't have an exact reference). I will ping Trond again about getting this upstream. > There is one more observation (on 2.6.37), when I pass > nfsroot=$(ip):$(rootpath),udp , then it works fine. > If I pass proto=udp then it doesn't work. Is there any difference > between the two methods ? It may be that proto=udp has an effect only on the transport used for NFS requests, but not for the MNT request. "udp" means "proto=udp,mountproto=udp." -- Chuck Lever chuck[dot]lever[at]oracle[dot]com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
