On Fri, Feb 21, 2014 at 02:26:41PM +1100, NeilBrown wrote: > On Thu, 20 Feb 2014 15:37:02 -0500 "J. Bruce Fields" <bfields@xxxxxxxxxxxx> > wrote: > > Any NFS server has to support either tcp or rpcbind. But it's OK for a > > server to support only of those two. So the only way to handle both > > cases while continuing to retry after ECONNREFUSED is to alternate > > between trying nfs4/tcp and rpcbind until you can connect to one or the > > other. > > > > If it's the rpcbind call that succeeds first then I think we want to do > > one more try of nfs4/tcp just to make sure it didn't just come up, > > before falling back to v3. > > > > The rpcbind call is done in userspace, if I understand right, so I think > > this is doable. Looking at utils/mount/ I don't understand the mount > > process well enough to understand exactly how to do it. Maybe > > everything but the final nfs_sys_mount needs to be moved out of > > nfs_do_mount_v3v2 into a new nfs_do_probe_v3v2 and nfs_autonegotiate > > should alternate between nfs_try_mount_v4 and nfs_do_probe_v3v2 as long > > as both return ECONNREFUSED, calling nfs_try_mount_v3v2 only if > > nfs_try_mount_v4 has failed after a succesful nfs_do_probe_v3v2? > > > > Except the v3v2 mount logic seems to actually modify the mount_options, > > so probably that doesn't quite work. > > I had come to much the same conclusion after reading Steve's mail: when TCP > fails we need rpcbind to be sure what to do. > I suspect it should be fairly straight forward to implement (I'm less > pessimistic than you). I'll have a go on Monday. OK, great! Yeah, the mount code looked like a maze for me but I probably spent less than an hour trying to trace through it, I'm sure it's not that bad. --b. -- 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
