diff --git a/cmd/syncthing/main.go b/cmd/syncthing/main.go
index 90ed07226..a6c344d87 100644
--- a/cmd/syncthing/main.go
+++ b/cmd/syncthing/main.go
@@ -18,6 +18,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"runtime/debug"
 	"runtime/pprof"
@@ -48,6 +49,14 @@ var (
 var l = logger.DefaultLogger
 
 func init() {
+	if Version != "unknown-dev" {
+		// If not a generic dev build, version string should come from git describe
+		exp := regexp.MustCompile(`^v\d+\.\d+\.\d+(-\d+-g[0-9a-f]+)?(-dirty)?$`)
+		if !exp.MatchString(Version) {
+			l.Fatalf("Invalid version string %q;\n\tdoes not match regexp %v", Version, exp)
+		}
+	}
+
 	stamp, _ := strconv.Atoi(BuildStamp)
 	BuildDate = time.Unix(int64(stamp), 0)
 
@@ -106,7 +115,9 @@ The following enviroment variables are interpreted by syncthing:
 
  STCPUPROFILE  Write CPU profile to the specified file.
 
- STGUIASSETS   Directory to load GUI assets from. Overrides compiled in assets.`
+ STGUIASSETS   Directory to load GUI assets from. Overrides compiled in assets.
+
+ STDEADLOCKTIMEOUT  Alter deadlock detection timeout (seconds; default 1200).`
 )
 
 func init() {
@@ -694,6 +705,9 @@ next:
 					wr = &limitedWriter{conn, rateBucket}
 				}
 				protoConn := protocol.NewConnection(remoteID, conn, wr, m)
+
+				l.Infof("Connection to %s established at %v", remoteID, conn.RemoteAddr())
+
 				m.AddConnection(conn, protoConn)
 				continue next
 			}
diff --git a/model/model.go b/model/model.go
index 6e78a30c9..ecb1ffab8 100644
--- a/model/model.go
+++ b/model/model.go
@@ -13,6 +13,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strconv"
 	"sync"
 	"time"
 
@@ -97,9 +98,16 @@ func NewModel(indexDir string, cfg *config.Configuration, clientName, clientVers
 		sup:           suppressor{threshold: int64(cfg.Options.MaxChangeKbps)},
 	}
 
-	deadlockDetect(&m.rmut, 60*time.Second)
-	deadlockDetect(&m.smut, 60*time.Second)
-	deadlockDetect(&m.pmut, 60*time.Second)
+	var timeout = 20 * 60 // seconds
+	if t := os.Getenv("STDEADLOCKTIMEOUT"); len(t) > 0 {
+		it, err := strconv.Atoi(t)
+		if err == nil {
+			timeout = it
+		}
+	}
+	deadlockDetect(&m.rmut, time.Duration(timeout)*time.Second)
+	deadlockDetect(&m.smut, time.Duration(timeout)*time.Second)
+	deadlockDetect(&m.pmut, time.Duration(timeout)*time.Second)
 	go m.broadcastIndexLoop()
 	return m
 }
@@ -366,15 +374,7 @@ func (m *Model) ClusterConfig(nodeID protocol.NodeID, config protocol.ClusterCon
 // Close removes the peer from the model and closes the underlying connection if possible.
 // Implements the protocol.Model interface.
 func (m *Model) Close(node protocol.NodeID, err error) {
-	if debug {
-		l.Debugf("%s: %v", node, err)
-	}
-
-	if err != io.EOF {
-		l.Warnf("Connection to %s closed: %v", node, err)
-	} else if _, ok := err.(ClusterConfigMismatch); ok {
-		l.Warnf("Connection to %s closed: %v", node, err)
-	}
+	l.Infof("Connection to %s closed: %v", node, err)
 
 	cid := m.cm.Get(node)
 	m.rmut.RLock()
@@ -857,8 +857,10 @@ func (m *Model) State(repo string) string {
 func (m *Model) Override(repo string) {
 	fs := m.NeedFilesRepo(repo)
 
-	m.rmut.Lock()
+	m.rmut.RLock()
 	r := m.repoFiles[repo]
+	m.rmut.RUnlock()
+
 	for i := range fs {
 		f := &fs[i]
 		h := r.Get(cid.LocalID, f.Name)
@@ -872,7 +874,6 @@ func (m *Model) Override(repo string) {
 		}
 		f.Version = lamport.Default.Tick(f.Version)
 	}
-	m.rmut.Unlock()
 
 	r.Update(cid.LocalID, fs)
 }
diff --git a/scanner/walk.go b/scanner/walk.go
index ec21f44e4..fff4ff359 100644
--- a/scanner/walk.go
+++ b/scanner/walk.go
@@ -106,7 +106,6 @@ func (w *Walker) loadIgnoreFiles(dir string, ign map[string][]string) filepath.W
 
 		if pn, sn := filepath.Split(rn); sn == w.IgnoreFile {
 			pn := filepath.Clean(pn)
-			l.Debugf("pn: %q", pn)
 			bs, _ := ioutil.ReadFile(p)
 			lines := bytes.Split(bs, []byte("\n"))
 			var patterns []string
@@ -287,7 +286,6 @@ func (w *Walker) ignoreFile(patterns map[string][]string, file string) bool {
 	for prefix, pats := range patterns {
 		if prefix == "." || prefix == first || strings.HasPrefix(first, fmt.Sprintf("%s%c", prefix, os.PathSeparator)) {
 			for _, pattern := range pats {
-				l.Debugf("%q %q", pattern, last)
 				if match, _ := filepath.Match(pattern, last); match {
 					return true
 				}