ais: fix node-join return values to avoid panic

Signed-off-by: Alex Aizman <[email protected]>

ais/htrun.go

@@ -1787,7 +1787,7 @@ func (h *htrun) extractRevokedTokenList(payload msPayload, caller string) (*toke
 //   - if these fails we try the candidates provided by the caller.
 //
 // ================================== Background =========================================
-func (h *htrun) join(query url.Values, htext htext, contactURLs ...string) (res *callResult) {
+func (h *htrun) join(query url.Values, htext htext, contactURLs ...string) (res *callResult, err error) {
 	var (
 		config                   = cmn.GCO.Get()
 		candidates               = make([]string, 0, 4+len(contactURLs))
@@ -1817,7 +1817,7 @@ func (h *htrun) join(query url.Values, htext htext, contactURLs ...string) (res
 	for range 4 { // retry
 		for _, candidateURL := range candidates {
 			if nlog.Stopping() {
-				return
+				return res, errors.New(h.String() + " is stopping")
 			}
 			if resPrev != nil {
 				freeCR(resPrev)
@@ -1837,20 +1837,23 @@ func (h *htrun) join(query url.Values, htext htext, contactURLs ...string) (res
 	}
 
 	smap := h.owner.smap.get()
-	if smap.validate() != nil {
-		return
+	if err := smap.validate(); err != nil {
+		return res, fmt.Errorf("%s: invalid Smap, err: %v", h.si, err)
 	}
 
 	// Failed to join cluster using config, try getting primary URL using existing smap.
 	nsti, _ := h.bcastHealth(smap, false /*checkAll*/)
-	if nsti == nil || nsti.Smap.Version < smap.version() {
-		return
+	if nsti == nil {
+		return res, fmt.Errorf("%s: failed to discover a new smap", h)
+	}
+	if nsti.Smap.Version < smap.version() {
+		return res, fmt.Errorf("%s: current %s version is newer than %d from the primary proxy (%s)", h, smap, nsti.Smap.Version, nsti.Smap.Primary.ID)
 	}
 	primaryURL = nsti.Smap.Primary.PubURL
 
 	// Daemon is stopping skip register
 	if nlog.Stopping() {
-		return
+		return res, errors.New(h.String() + " is stopping")
 	}
 	res = h.regTo(primaryURL, nil, apc.DefaultTimeout, query, htext, false /*keepalive*/)
 	if res.err == nil {

ais/proxy.go

@@ -261,11 +261,13 @@ func (p *proxy) joinCluster(action string, primaryURLs ...string) (status int, e
 	if cmn.GCO.Get().Proxy.NonElectable {
 		query = url.Values{apc.QparamNonElectable: []string{"true"}}
 	}
-	res := p.join(query, nil /*htext*/, primaryURLs...)
+	res, err := p.join(query, nil /*htext*/, primaryURLs...)
+	if err != nil {
+		return status, err
+	}
 	defer freeCR(res)
 	if res.err != nil {
-		status, err = res.status, res.err
-		return
+		return res.status, res.err
 	}
 	// not being sent at cluster startup and keepalive
 	if len(res.bytes) == 0 {

ais/tgtcp.go

@@ -48,11 +48,13 @@ type delb struct {
 }
 
 func (t *target) joinCluster(action string, primaryURLs ...string) (status int, err error) {
-	res := t.join(nil, t, primaryURLs...)
+	res, err := t.join(nil, t, primaryURLs...)
+	if err != nil {
+		return status, err
+	}
 	defer freeCR(res)
 	if res.err != nil {
-		status, err = res.status, res.err
-		return
+		return res.status, res.err
 	}
 	// not being sent at cluster startup and keepalive
 	if len(res.bytes) == 0 {