On Jan 13, 2009, at Jan 13, 2009, 12:44 PM, Trond Myklebust wrote:
On Tue, 2009-01-13 at 12:31 -0500, Chuck Lever wrote:Detect the case where we sent an rpcbind v4 SET but user space doesn'tsupport rpcbind protocol version 4.When registering an AF_INET service, a warning is sent to the log once, and we down-shift to version 2. With AF_INET6, an error is always sentto the log, and the registration fails. This should help distributors and testers determine why their NFSD service won't start, but normal users/admins should really never see this message unless something very strange has happened. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/svc.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 files changed, 38 insertions(+), 6 deletions(-) diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index e93bc55..daed77f 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -736,6 +736,18 @@ static void __svc_rpcb_prog_mismatch_error(void) } }+static int __svc_rpcb_cant_register(const char *progname, const u32 version)+{ + printk(KERN_ERR + "svc: Could not register an IPv6 listener for %s v%u " + "with the local portmapper.\n" + "svc: The kernel tried an rpcbind version 4 request, " + "but your portmapper\n" + "svc: does not support rpcbind version 4.", + progname, version); + return -EAFNOSUPPORT; +}This is ___way___ too intrusive...
We already have stuff like the NFSv4 callback channel that automaticallyassumes that it should use an IPv6 registration as long as CONFIG_IPV6 or CONFIG_IPV6_MODULE are defined.
I believe the callback channel service does not register itself with the local portmapper. This function wouldn't be invoked in that case.
Compiling in IPv6 without having an IPv6-capable portmapper should certainly not be flagged as a kernel error.
It's an error if the kernel can't register an RPC service that asked to be registered, isn't it?
But the point I _think_ you're making is that enabling kernel IPv6 support (outside of RPC) shouldn't cause problems like this. If CONFIG_SUNRPC_REGISTER_V4 is not set, then IPv6 RPC listeners for lockd and NFSD aren't created at all, even if CONFIG_IPV6 is enabled, and this problem is avoided.
(I think proper dependencies exist to make this work right today, but it's pretty confusing. An additional CONFIG entry for explicitly enabling lockd and NFSD via IPv6 would make this better understood).
The other problem here is that when registering an IPv6 RPC service, the kernel uses an IPv6 loopback address to test whether the user space portmapper is actually IPv6 enabled. I expect this is why the new kernel running with the old user space never got "program version mismatch" -- the portmapper wasn't listening on IPv6 to reply to the request.
This was the reason I wanted to use a connected transport for registration upcalls -- then rpcb_v4_register could tell immediately that user space wasn't prepared for kernel IPv6 RPC services, instead of timing out after many seconds.
We can switch to always use IPv4 for the registration upcall to avoid this problem and retain backwards compatibility. However, this means that the kernel can't detect whether user space is really IPv6 enabled. It can only tell whether rpcbindv4 is supported. Do we think that is sufficient? (I'll hazard a guess that the answer is "yes").
/* * Register an "inet" protocol family netid with the local * rpcbind daemon via an rpcbind v4 SET request.@@ -811,10 +823,14 @@ static int __svc_rpcb_register6(const u32 program, const u32 version,/* * Register a kernel RPC service via rpcbind version 4. * + * This logic is complicated by the case where user space is not + * running a portmapper that can handle a verison 4 request. + * * Returns zero on success; a negative errno value is returned * if any error occurs. */ -static int __svc_register(const u32 program, const u32 version, +static int __svc_register(const char *progname, + const u32 program, const u32 version, const sa_family_t family, const unsigned short protocol, const unsigned short port)@@ -823,11 +839,25 @@ static int __svc_register(const u32 program, const u32 version,switch (family) { case AF_INET: - return __svc_rpcb_register4(program, version, - protocol, port); + if (__svc_register_version == 4) { + error = __svc_rpcb_register4(program, version, + protocol, port); + if (error != -EPROTONOSUPPORT) + return error; + } + + /* Down-shift. */ + __svc_rpcb_prog_mismatch_error(); + return rpcb_register(program, version, protocol, port); case AF_INET6: + /* This won't work if we don't have version 4. */ + if (__svc_register_version != 4) + return __svc_rpcb_cant_register(progname, version); + error = __svc_rpcb_register6(program, version, protocol, port); + if (error == -EPROTONOSUPPORT) + return __svc_rpcb_cant_register(progname, version); if (error < 0) return error;@@ -854,7 +884,8 @@ static int __svc_register(const u32 program, const u32 version,* Returns zero on success; a negative errno value is returned * if any error occurs. */ -static int __svc_register(const u32 program, const u32 version, +static int __svc_register(const char *progname, + const u32 program, const u32 version, sa_family_t family, const unsigned short protocol, const unsigned short port)@@ -901,8 +932,9 @@ int svc_register(const struct svc_serv *serv, const unsigned short proto,if (progp->pg_vers[i]->vs_hidden) continue; - error = __svc_register(progp->pg_prog, i, - serv->sv_family, proto, port); + error = __svc_register(progp->pg_name, progp->pg_prog, + i, serv->sv_family, + proto, port); if (error < 0) break; } --To unsubscribe from this list: send the line "unsubscribe linux- nfs" inthe body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
-- 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
