middleware/file: reload on file mv (#365)

When a file is moved into position we should also reload the zones'
content.

This also fixes deadlock bug in the locking, a reload would block any
further lookups.

middleware/file/lookup.go

@@ -29,28 +29,36 @@ func (z *Zone) Lookup(qname string, qtype uint16, do bool) ([]dns.RR, []dns.RR,
 		if !z.NoReload {
 			z.reloadMu.RLock()
 		}
-		return z.lookupSOA(do)
+
+		r1, r2, r3, res := z.lookupSOA(do)
+
 		if !z.NoReload {
 			z.reloadMu.RUnlock()
 		}
+		return r1, r2, r3, res
 	}
 	if qtype == dns.TypeNS && qname == z.origin {
 		if !z.NoReload {
 			z.reloadMu.RLock()
 		}
-		return z.lookupNS(do)
+
+		r1, r2, r3, res := z.lookupNS(do)
+
 		if !z.NoReload {
 			z.reloadMu.RUnlock()
 		}
+		return r1, r2, r3, res
 	}
 
 	if !z.NoReload {
 		z.reloadMu.RLock()
 	}
+
 	elem, res := z.Tree.Search(qname, qtype)
 	if !z.NoReload {
 		z.reloadMu.RUnlock()
 	}
+
 	if elem == nil {
 		if res == tree.EmptyNonTerminal {
 			return z.emptyNonTerminal(qname, do)

middleware/file/zone.go

@@ -123,8 +123,10 @@ func (z *Zone) TransferAllowed(req request.Request) bool {
 // All returns all records from the zone, the first record will be the SOA record,
 // otionally followed by all RRSIG(SOA)s.
 func (z *Zone) All() []dns.RR {
-	z.reloadMu.RLock()
-	defer z.reloadMu.RUnlock()
+	if !z.NoReload {
+		z.reloadMu.RLock()
+		defer z.reloadMu.RUnlock()
+	}
 
 	records := []dns.RR{}
 	allNodes := z.Tree.All()
@@ -162,7 +164,9 @@ func (z *Zone) Reload() error {
 		for {
 			select {
 			case event := <-watcher.Events:
-				if event.Op == fsnotify.Write && path.Clean(event.Name) == z.file {
+				// Looks for Write and Create events. Write is obvious, Create is used when
+				// a file in mv-ed into this place.
+				if (event.Op == fsnotify.Write || event.Op == fsnotify.Create) && path.Clean(event.Name) == z.file {
 
 					reader, err := os.Open(z.file)
 					if err != nil {