nfs4: set source address when callback is generated

when callback is generated in NFSv4 server, it doesn't set the source
address. When an alias IP is utilized on NFSv4 server and suppose the
client is accessing via that alias IP (e.g. eth0:0), the client invokes
the callback to the IP address that is set on the original device (e.g.
eth0). This behavior results in timeout of xprt.
The patch sets the IP address that the client should invoke callback to.

Signed-off-by: Takuma Umeya <tumeya@redhat.com>
[bfields@redhat.com: Simplify gen_callback arguments, use helper function]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4callback.c

@@ -484,6 +484,7 @@ static int setup_callback_client(struct nfs4_client *clp,
 		.net		= &init_net,
 		.address	= (struct sockaddr *) &conn->cb_addr,
 		.addrsize	= conn->cb_addrlen,
+		.saddress	= (struct sockaddr *) &conn->cb_saddr,
 		.timeout	= &timeparms,
 		.program	= &cb_program,
 		.version	= 0,

fs/nfsd/nfs4state.c

@@ -1163,10 +1163,26 @@ find_unconfirmed_client_by_str(const char *dname, unsigned int hashval)
 	return NULL;
 }
 
+static void rpc_svcaddr2sockaddr(struct sockaddr *sa, unsigned short family, union svc_addr_u *svcaddr)
+{
+	switch (family) {
+	case AF_INET:
+		((struct sockaddr_in *)sa)->sin_family = AF_INET;
+		((struct sockaddr_in *)sa)->sin_addr = svcaddr->addr;
+		return;
+	case AF_INET6:
+		((struct sockaddr_in6 *)sa)->sin6_family = AF_INET6;
+		((struct sockaddr_in6 *)sa)->sin6_addr = svcaddr->addr6;
+		return;
+	}
+}
+
 static void
-gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, u32 scopeid)
+gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, struct svc_rqst *rqstp)
 {
 	struct nfs4_cb_conn *conn = &clp->cl_cb_conn;
+	struct sockaddr	*sa = svc_addr(rqstp);
+	u32 scopeid = rpc_get_scope_id(sa);
 	unsigned short expected_family;
 
 	/* Currently, we only support tcp and tcp6 for the callback channel */
@@ -1192,6 +1208,7 @@ gen_callback(struct nfs4_client *clp, struct nfsd4_setclientid *se, u32 scopeid)
 
 	conn->cb_prog = se->se_callback_prog;
 	conn->cb_ident = se->se_callback_ident;
+	rpc_svcaddr2sockaddr((struct sockaddr *)&conn->cb_saddr, expected_family, &rqstp->rq_daddr);
 	return;
 out_err:
 	conn->cb_addr.ss_family = AF_UNSPEC;
@@ -1768,7 +1785,6 @@ __be32
 nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		  struct nfsd4_setclientid *setclid)
 {
-	struct sockaddr		*sa = svc_addr(rqstp);
 	struct xdr_netobj 	clname = { 
 		.len = setclid->se_namelen,
 		.data = setclid->se_name,
@@ -1871,7 +1887,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	 * for consistent minorversion use throughout:
 	 */
 	new->cl_minorversion = 0;
-	gen_callback(new, setclid, rpc_get_scope_id(sa));
+	gen_callback(new, setclid, rqstp);
 	add_to_unconfirmed(new, strhashval);
 	setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
 	setclid->se_clientid.cl_id = new->cl_clientid.cl_id;

fs/nfsd/state.h

@@ -96,6 +96,7 @@ struct nfs4_delegation {
 struct nfs4_cb_conn {
 	/* SETCLIENTID info */
 	struct sockaddr_storage	cb_addr;
+	struct sockaddr_storage	cb_saddr;
 	size_t			cb_addrlen;
 	u32                     cb_prog; /* used only in 4.0 case;
 					    per-session otherwise */